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  1. Metal-on-metal total hip arthroplasty: the concerns.

    PubMed

    MacDonald, S J

    2004-12-01

    The metal-on-metal bearing couple is having a resurgence in clinical applications seen in total hip and hip resurfacing technologies. The most noteworthy advantage of a metal-on-metal implant is the improved wear characteristics seen in vitro on wear simulators and in vivo with retrieved implants. All bearings have disadvantages, and a metal-on-metal bearing is no exception. Concerns exist regarding the generation of metal ions seen in the blood and urine of patients with metal-on-metal implants. These elevated metal ions have theoretical, although not proven, risks related to carcinogenic and biologic concerns. Additionally, concerns exist regarding hypersensitivity, increased incidence of instability and increased costs. Specific patient selection issues arise with metal-on-metal implants. The current generation of implants has only early and mid-term results available, with no long-term series yet published. Therefore, although a metal-on-metal bearing may be considered a viable alternative to either polyethylene or ceramic implants, outstanding and unresolved issues continue to exist with this bearing, as they do with the alternatives. PMID:15577471

  2. Metal-on-Metal Total Hip Resurfacing Arthroplasty

    PubMed Central

    2006-01-01

    Executive Summary Objective 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. Clinical Need 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. The Technology 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

  3. TOTAL DISSOLVED AND BIOAVAILABLE METALS AT LAKE TEXOMA MARINAS

    EPA Science Inventory

    Dissolved metals in water and total metals in sediments have been measured at marina areas in Lake Texoma during June 1999 to October 2001, and October 2001, respectively. The metals most often found in the highest concentrations in marina water were Na and Ca, followed by Mg an...

  4. Total omnidirectional reflection by sub-wavelength gradient metallic gratings

    NASA Astrophysics Data System (ADS)

    Qian, Erting; Fu, Yangyang; Xu, Yadong; Chen, Huanyang

    2016-05-01

    In this letter, we find that nearly total omnidirectional reflection could be achieved in a metallic grating structure with gradient index materials, regardless of the polarization of the incident wave. By bending the straight structure into a metallic grating ring, we design a metacage that can well shield the electromagnetic wave. All the phenomena are well demonstrated from theoretical analysis and numerical simulations.

  5. Total Knee Arthroplasty Failure Induced by Metal Hypersensitivity

    PubMed Central

    Gupta, Ryan; Phan, Duy; Schwarzkopf, Ran

    2015-01-01

    Patient: Female, 70 Final Diagnosis: Metal hypersensitivity Symptoms: Joint pain • swelling • instability Medication: — Clinical Procedure: Revision total knee arthroplasty Specialty: Orthopedics and Traumatology Objective: Unusual clinical course Background: Metal hypersensitivity is an uncommon complication after total knee arthroplasty (TKA) that can lead to significant functional impairment and aseptic prosthesis failure. Case Report: We describe a 70-year-old patient who presented with persistent pain, swelling, and instability 2 years after a primary TKA. The patient had a history of metal hypersensitivity following bilateral metal-on-metal total hip arthroplasty (THA) that was revised to ceramic-on-polyethylene implants. Knee radiographs showed severe osteolysis with implant loosening. Serum cobalt was elevated and serum chromium was significantly elevated, while joint aspiration and inflammatory marker levels ruled out a periprosthetic infection. Revision TKA was performed, with intraoperative tissue pathology and postoperative leukocyte transformation testing confirming metal hypersensitivity as the cause for aseptic implant failure. Conclusions: This case report demonstrates the clinical and laboratory signs that suggest metal hypersensitivity in total knee arthroplasty and the potential for joint function restoration with revision surgery. PMID:26278890

  6. Metallic debris from metal-on-metal total hip arthroplasty regulates periprosthetic tissues

    PubMed Central

    Lohmann, Christoph H; Singh, Gurpal; Willert, Hans-Georg; Buchhorn, Gottfried H

    2014-01-01

    The era of metal-on-metal (MoM) total hip arthroplasty has left the orthopaedic community with valuable insights and lessons on periprosthetic tissue reactions to metallic debris. Various terms have been used to describe the tissue reactions. Sometimes the nomenclature can be confusing. We present a review of the concepts introduced by Willert and Semlitsch in 1977, along with further developments made in the understanding of periprosthetic tissue reactions to metallic debris. We propose that periprosthetic tissue reactions be thought of as (1) gross (metallosis, necrosis, cyst formation and pseudotumour); (2) histological (macrophage-dominated, lymphocyte-dominated or mixed); and (3) molecular (expression of inflammatory mediators and cytokines such as interleukin-6 and tumor necrosis factor-alpha). Taper corrosion and modularity are discussed, along with future research directions to elucidate the antigen-presenting pathways and material-specific biomarkers which may allow early detection and intervention in a patient with adverse periprosthetic tissue reactions to metal wear debris. PMID:25405095

  7. The Clinical Performance of Metal-on-Metal as an Articulation Surface in Total Hip Replacement

    PubMed Central

    Long, William T

    2005-01-01

    The metal-on-metal articulations in total hip arthroplasty (THA) were widely used between 1960 and 1975. The McKee-Farrar and other first-generation prostheses failed at a high rate because impingement caused early component loosening. The problem of early component loosening was corrected by improved component design and better manufacturing quality. Second-generation metal-on-metal total hip replacements have experienced short and medium-term success as assessed by Harris Hip Scores and patient selfassessment. The combined annual linear wear of the metal-on-metal femoral head and acetabular insert is less than 10 mm and osteolysis has only rarely been observed in association with well-fixed metal-on-metal total hip replacements. Hypersensitivity is not a common cause of loosening with second-generation hip replacements and remains to be proven as a definitive diagnosis in unusual cases of unexplained pain. More than 40 years of use has demonstrated no increase in the incidence of renal failure or cancer in patients with metal-on-metal total hip replacements. The scientific evidence of the results using the metal-on-metal articulations would recommend its continued use in any patient who does not have compromised renal function. PMID:16089065

  8. Clean Air Act requirements for trace-metals information

    SciTech Connect

    Pahl, D.; Hunt, W.; Evans, G.

    1992-01-01

    The Clean Air Act Amendments of 1990 have expanded the requirements for trace metal and air toxics information in urban areas and added new requirements for this information in rural areas and ecosystems. Specific provisions germane to trace metals and other air toxics compounds are found in Title III, Section 112 and in Title IX, Section 901. In response to these provisions, the United States Environmental Protection Agency (EPA) plans to conduct research in atmospheric monitoring networks in urban areas, in the Great Lakes watershed, and in regional components of a national Clean Air Act status and trends network.

  9. Metal sensitivity before and after total hip arthroplasty.

    PubMed

    Deutman, R; Mulder, T J; Brian, R; Nater, J P

    1977-10-01

    Of 212 patients undergoing total hip replacement who were tested preoperatively for sensitivity to nickel, chromium, and cobalt, fourteen showed sensitivity. No sensitivity to the bone cement was recorded. Of 173 patients who had never had a metal implant before, 5.8 per cent showed a positive reaction. Two patients out of fifteen with a failed McKee-Farrar prosthesis were found to be sensitive. Of six patients who had a stable McKee-Farrar prosthesis in the other hip, none showed sensitivity to the metal. In four of sixty-six patients, sensitivity to nickel or cobalt developed after the implantation of a metal-to-plastic prosthesis. No patients were sensitized to the cement. The consequences of proved hypersensitivity in patients with metal-to-plastic prostheses, either present prior to insertion of the prosthesis or evoked by the implant material, are not known. PMID:908716

  10. Complications Related to Metal-on-Metal Articulation in Trapeziometacarpal Joint Total Joint Arthroplasty

    PubMed Central

    Frølich, Christina; Hansen, Torben Bæk

    2015-01-01

    Adverse reactions to metal-on-metal (MoM) prostheses are well known from total hip joint resurfacing arthroplasty with elevated serum chrome or cobalt, pain and pseudo tumor formation. It may, however, also be seen after total joint replacement of the trapeziometacarpal joint using MoM articulation, and we present two cases of failure of MoM prostheses due to elevated metal-serum levels in one case and pseudo tumor formation in another case. Furthermore, we suggest a diagnostic algorithm for joint pain after MoM trapeziometacarpal joint replacement based on published experiences from MoM hip prostheses and adverse reactions to metal. PMID:26020592

  11. The characterization of total and leachable metals in foundry molding sands.

    PubMed

    Dungan, Robert S; Dees, Nikki H

    2009-01-01

    Waste molding sands from the foundry industry have been successfully used as a component in manufactured soils, but concern over metal contamination must be addressed before many states will consider this beneficial use. Since there is little data available on this topic, the purpose of this study was to characterize total and leachable metals from waste molding sands. A total elemental analysis for Ag, Al, As, B, Ba, Be, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sb, V, and Zn was conducted on 36 clay-bonded and seven chemically bonded molding sands. Total metal concentrations in the molding sands were similar to those found in agricultural soils. The leaching of metals (i.e. Ag, As, Ba, Be, Cd, Cr, Cu, Ni, Pb, Sb, and Zn) was assessed via the toxicity characteristic leaching procedure (TCLP), synthetic precipitation leaching procedure (SPLP), and ASTM water leach test. Based on the TCLP data, none of the 43 molding sands would meet the Resource Conservation and Recovery Act (RCRA) characteristic for toxicity due to high Ag, As, Ba, Cd, Cr, and Pb. Compared to the TCLP results, the metal concentrations were generally lower in the SPLP and ASTM extracts, which is likely related to the buffering capacity of the extraction fluids. PMID:18194836

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

    NASA Astrophysics Data System (ADS)

    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.

  13. Correlation between the limiting pH of metal ion solubility and total metal concentration

    SciTech Connect

    Apak, R.; Hizal, J.; Ustaer, C.

    1999-03-15

    As an alternative to species distribution diagrams (pM vs pH curves in aqueous solution) drawn for a fixed total metal concentration, this work has developed simple linear models for correlating the limiting pH of metal ion solubility -- in equilibrium with the least soluble amorphous metal hydroxide solid phase -- to the total metal concentration. Thus adsorptive metal removal processes in complex systems can be better designed once the limiting pH of heavy metal solubility (i.e., pH{sup *}) in such a complex environment can be envisaged by simple linear equations. pH{sup *} vs pM{sub t} (M{sub t} = total metal concentration that can exist in aqueous solution in equilibrium with M(OH){sub 2(s)}) linear curves for uranyl-hydroxide, uranyl-carbonate-hydroxide, and mercuric-chloride-hydroxide simple and mixed-ligand systems and cupric-carbonate-hydroxide complexes in equilibrium with mixed hydroxide solid phases may enable the experimental chemist to distinguish true adsorption (e.g., onto hydrous oxide sorbents) from bulk precipitation removal of the metal and to interpret some anomalous metal fixation data -- usually attributed to pure adsorption in the literature -- with precipitation if the pM{sub t} at the studied pH is lower than that tolerated by pH{sup *} vs pM{sub t} curves. This easily predictable pH{sup *} corresponding to a given pM{sub t} may aid the design of desorptive mobilization experiments for certain metals as well as their adsorptive removal with the purpose of simulating metal adsorption and desorption cycles in real complex environments with changing groundwater pH.

  14. Early surveillance of ceramic-on-metal total hip arthroplasty.

    PubMed

    Hill, J C; Diamond, O J; O'Brien, S; Boldt, J G; Stevenson, M; Beverland, D E

    2015-03-01

    Ceramic-on-metal (CoM) is a relatively new bearing combination for total hip arthroplasty (THA) with few reported outcomes. A total of 287 CoM THAs were carried out in 271 patients (mean age 55.6 years (20 to 77), 150 THAs in female patients, 137 in male) under the care of a single surgeon between October 2007 and October 2009. With the issues surrounding metal-on-metal bearings the decision was taken to review these patients between March and November 2011, at a mean follow-up of 34 months (23 to 45) and to record pain, outcome scores, radiological analysis and blood ion levels. The mean Oxford Hip Score was 19.2 (12 to 53), 254 patients with 268 hips (95%) had mild/very mild/no pain, the mean angle of inclination of the acetabular component was 44.8(o) (28(o) to 63(o)), 82 stems (29%) had evidence of radiolucent lines of > 1 mm in at least one Gruen zone and the median levels of cobalt and chromium ions in the blood were 0.83 μg/L (0.24 μg/L to 27.56 μg/L) and 0.78 μg/L (0.21 μg/L to 8.84 μg/L), respectively. The five-year survival rate is 96.9% (95% confidence interval 94.7% to 99%). Due to the presence of radiolucent lines and the higher than expected levels of metal ions in the blood, we would not recommend the use of CoM THA without further long-term follow-up. We plan to monitor all these patients regularly. PMID:25737511

  15. Does bearing size influence metal ion levels in large-head metal-on-metal total hip arthroplasty? A comparison of three total hip systems

    PubMed Central

    2014-01-01

    Background The purpose of the study was twofold: first, to determine whether there is a statistically significant difference in the metal ion levels among three different large-head metal-on-metal (MOM) total hip systems. The second objective was to assess whether position of the implanted prostheses, patient demographics or factors such as activity levels influence overall blood metal ion levels and whether there is a difference in the functional outcomes between the systems. Methods In a cross-sectional cohort study, three different metal-on-metal total hip systems were assessed: two monoblock heads, the Durom socket (Zimmer, Warsaw, IN, USA) and the Birmingham socket (Smith and Nephew, Memphis, TN, USA), and one modular metal-on-metal total hip system (Pinnacle, Depuy Orthopedics, Warsaw, IN, USA). Fifty-four patients were recruited, with a mean age of 59.7 years and a mean follow-up time of 41 months (12 to 60). Patients were evaluated clinically, radiologically and biochemically. Statistical analysis was performed on all collected data to assess any differences between the three groups in terms of overall blood metal ion levels and also to identify whether there was any other factor within the group demographics and outcomes that could influence the mean levels of Co and Cr. Results Although the functional outcome scores were similar in all three groups, the blood metal ion levels in the larger monoblock large heads (Durom, Birmingham sockets) were significantly raised compared with those of the Pinnacle group. In addition, the metal ion levels were not found to have a statistically significant relationship to the anteversion or abduction angles as measured on the radiographs. Conclusions When considering a MOM THR, the use of a monoblock large-head system leads to higher elevations in whole blood metal ions and offers no advantage over a smaller head modular system. PMID:24472283

  16. Metal release and metal allergy after total hip replacement with resurfacing versus conventional hybrid prosthesis

    PubMed Central

    Gustafson, Klas; Jakobsen, Stig S; Lorenzen, Nina D; Thyssen, Jacob P; Johansen, Jeanne D; Bonefeld, Charlotte M; Stilling, Maiken; Baad-Hansen, Thomas; Søballe, Kjeld

    2014-01-01

    Background Metal-on-metal (MOM) total hip arthroplasties were reintroduced because of the problems with osteolysis and aseptic loosening related to polyethylene wear of early metal-on-polyethylene (MOP) arthroplasties. The volumetric wear rate has been greatly reduced with MOM arthroplasties; however, because of nano-size wear particles, the absolute number has been greatly increased. Thus, a source of metal ion exposure with the potential to sensitize patients is present. We hypothesized that higher amounts of wear particles result in increased release of metal ions and ultimately lead 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 3 months, and after 1, 2, and 5 years and tested with inductively coupled plasma-sector field mass spectrometry. After 5 years, hypersensitivity to metals was evaluated by patch testing and lymphocyte transformation assay. In addition, the patients answered a questionnaire about hypersensitivity. 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 in the urine during the entire follow-up period, no difference in prevalence of metal allergy was observed in the MOM group. However, the effect of long-term metal exposure remains uncertain. PMID:24930546

  17. Determination of total metal pollutants in water with optical detection

    NASA Astrophysics Data System (ADS)

    Chudy, Michal; Prokaryn, Piotr; Dybko, Artur; Wroblewski, Wojciech; Brzozka, Zbigniew

    2003-09-01

    The total concentration of heavy metal ions was measured with the use of a highly sensitive reagent (4-(2-pyridylzo)-resorcinol (PAR)). Because of PAR chelates are slightly soluble in water and their forming is not selective, the analytical procedure for Cd, Cu, Hg, Pb, Zn determination was developed to perform the analysis in an aqueous environment without the need of inconvenient and time-consuming extraction. A proposed analysis method is more useful in comparison with classical FIA analysis what is crucial during fast classification of various natural water samples. To minimize the chemicals consumption such a classification can be performed in a specially designed microsystem. The Y- shape microchannel structure with a mixing area was made by fine engraving in PMMA plate and sealed with the PDMS one. The M2+-PAR complex forming conditions were determined for each of the chosen metal ions. The solubility of formed complexes was better when a micellar environment was created by the addition of a non-ionic surfactant (Triton X100). Next the synthetic mixtures of Cd, Cu, Hg, Pb, Zn ions were prepared to obtain total molar metal ions concentration in the range from 10-6 to 10-4 M and measured after on-chip reaction. A tap water and HAC-sample (Highest Allowable Concentration, ΣMe=1,2•10-5 M) were also measured. The detection was performed in a special flow cuvette and spectra measurements were carried out using diode array spectrophotometer and CCD detector.

  18. Survivorship of Trabecular Metal Anchored Glenoid Total Shoulder Arthroplasties.

    PubMed

    Styron, Joseph F; Marinello, Patrick G; Peers, Sebastian; Seitz, William H

    2016-09-01

    Trabecular metal anchored glenoids (TMAGs) were developed to counter the pervasive problem of component loosening at the bone-cement interface in total shoulder arthroplasty. Increased failure rates associated with the glenoid component have been previously reported due to increased rates of glenoid failures. Our hypothesis was that in our patients, the failure rate of TMAG implants is similar to or less than reported failure rates of traditional all polyethylene glenoid components. A medical chart review of 66 consecutive patients treated with a TMAG total shoulder replacement was conducted including clinical and radiographic follow-up. Paired t test analyses were used to compare the patients' preoperative and postoperative shoulder range of motion. Patients on average had 50.2 months of clinical follow-up available. Although the radiographs of several patients demonstrated focal areas of lucency, none of the patients demonstrated evidence of glenoid loosening. Glenoid component failure was a rare occurrence, happening only once in the 66 patients (1.5%). The patient with a glenoid fracture sustained that complication 6 years after her index total shoulder replacement. She was the only patient in the series who required revision surgery. Most patients experienced significant improvements in their shoulder range of motion, improving forward flexion from 73.7 to 144.2 degrees (P<0.0001), internal rotation from L5 to T8 (P<0.0001), and external rotation 12.8 to 48.9 degrees (P<0.0001). With improved implant design and meticulous surgical technique, recent iterations of TMAG components do not produce excessive failure rates but result in significant functional improvements. PMID:27328424

  19. Short-term results with the Zweymueller-SL metal-on-metal total hip arthroplasty.

    PubMed

    Korovessis, Panagiotis; Petsinis, Georgios; Repanti, Maria; Papazisis, Zisis; Iliopoulos, Panagiotis; Soucacos, Panagiotis N

    2002-01-01

    In a prospective study we followed 266 consecutive patients who received 350 Zweymueller-SL uncemented total hip replacements with metal-on-metal articulation for osteoarthritis. Mean follow-up was 52 (range 37-92) months. Patient age at the time of surgery was 55±9 (25-70) years. Pre-operative Harris score of 45±19 was increased post-operatively to 96±4. Pre-operative invalidity was significantly improved post-operatively (P<0.001), and 97% of the patients were either satisfied or very satisfied with the results. There was no aseptic loosening of either component. Revision was made in six hips (1.8%) because of either septic loosening (five, 1.5%) or technical error (one, 0.3%). At revision, surgical microscopic evidence for metalosis (Mirra grades 1 and 2) was shown in all revised hips. The reasons for early loosening were unrelated to the metal-on-metal bearing but rather were the result of either low-grade deep infection or inadequate surgical technique. Survival rate for Zweymueller screw socket and stem 7.6 years after implantation was 99.4% and 96.8% respectively. There was no evidence that metal-on-metal articulation gives rise to new problems or complications. PMID:24570158

  20. Metal-on-metal total hip arthroplasty: is there still a role in 2016?

    PubMed

    Silverman, Edward J; Ashley, Blair; Sheth, Neil P

    2016-03-01

    The use of metal-on-metal (MoM) bearings in total hip arthroplasty (THA) was popularized due to its enhanced wear profile and the ability to use large femoral heads to reduce post-operative instability. However, enthusiasm for the bearing declined following serious complications encountered at the primary articulation. This review discusses the development of MoM and the subsequent unexpected downstream challenges, most notably elevated serum metal ion levels, aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL), pseudotumor formation, and subsequent soft tissue and bone destruction. Both patient centered risk factors as well as component design led to high early failure rates resulting in product recalls and an overall decline in the use of MoM. In 2016, there is not a role for large-head MoM bearing in THA. Alternatively, the bearing has shown promise in hip resurfacing procedures for carefully selected patients. PMID:26791173

  1. 76 FR 72495 - Alabama Metal Coil Securement Act; Petition for Determination of Preemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-23

    ... TRANSPORTATION Federal Motor Carrier Safety Administration Alabama Metal Coil Securement Act; Petition for... determination that the State of Alabama's Metal Coil Securement Act is preempted by Federal law. FMCSA requests comments on what effect, if any, Alabama's metal coil load securement certification requirements may...

  2. No association between serum metal ions and implant fixation in large-head metal-on-metal total hip arthroplasty

    PubMed Central

    Søballe, Kjeld; Jakobsen, Stig Storgaard; Lorenzen, Nina Dyrberg; Mechlenburg, Inger; Stilling, Maiken

    2014-01-01

    Background The mechanism of failure of metal-on-metal (MoM) total hip arthroplasty (THA) has been related to a high rate of metal wear debris, which is partly generated from the head-trunnion interface. However, it is not known whether implant fixation is affected by metal wear debris. Patients and methods 49 cases of MoM THA in 41 patients (10 women) with a mean age of 52 (28–68) years were followed with stereoradiographs after surgery and at 1, 2, and 5 years to analyze implant migration by radiostereometric analysis (RSA). Patients also participated in a 5- to 7-year follow-up with measurement of serum metal ions, questionnaires (Oxford hip score (OHS) and Harris hip score (HHS)), and measurement of cup and stem positions and systemic bone mineral density. Results At 1–2 years, mean total translation (TT) was 0.04 mm (95% CI: –0.07 to 0.14; p = 0.5) for the stems; at 2–5 years, mean TT was 0.13 mm (95% CI: –0.25 to –0.01; p = 0.03), but within the precision limit of the method. For the cups, there was no statistically significant TT or total rotation (TR) at 1–2 and 2–5 years. At 2–5 years, we found 4 cups and 5 stems with TT migrations exceeding the precision limit of the method. There was an association between cup migration and total OHS < 40 (4 patients, 4 hips; p = 0.04), but there were no statistically significant associations between cup or stem migration and T-scores < –1 (n = 10), cup and stem positions, or elevated serum metal ion levels (> 7µg/L (4 patients, 6 hips)). Interpretation Most cups and stems were well-fixed at 1–5 years. However, at 2–5 years, 4 cups and 5 stems had TT migrations above the precision limits, but these patients had serum metal ion levels similar to those of patients without measurable migrations, and they were pain-free. Patients with serum metal ion levels > 7 µg/L had migrations similar to those in patients with serum metal ion levels < 7 µg/L. Metal wear debris does not appear to influence the

  3. Friction in metal-on-metal total disc arthroplasty: effect of ball radius.

    PubMed

    Moghadas, Parshia; Mahomed, Aziza; Hukins, David W L; Shepherd, Duncan E T

    2012-02-01

    Total disc arthroplasty (TDA) can be used to replace a degenerated intervertebral disc in the spine. There are different designs of prosthetic discs, but one of the most common is a ball-and-socket combination. Contact between the bearing surfaces can result in high frictional torque, which can then result in wear and implant loosening. This study was designed to determine the effects of ball radius on friction. Generic models of metal-on-metal TDA were manufactured with ball radii of 10, 12, 14 and 16 mm, with a radial clearance of 0.015 mm. A simulator was used to test each sample in flexion-extension, lateral bending and axial rotation at frequencies of 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75 and 2 Hz under loads of 50, 600, 1200 and 2000 N, in new born calf serum. Frictional torque was measured and Stribeck curves were plotted to illustrate the lubrication regime in each case. It was observed that implants with a smaller ball radius showed lower friction and showed boundary and mixed lubrication regimes, whereas implants with larger ball radius showed boundary lubrication only. This study suggests designing metal-on-metal TDAs with ball radius of 10 or 12 mm, in order to reduce wear and implant loosening. PMID:22177670

  4. High Re-Operation Rates Using Conserve Metal-On-Metal Total Hip Articulations

    PubMed Central

    Mogensen, S.L.; Jakobsen, T.; Christoffersen, H.; Krarup, N.

    2016-01-01

    Introduction: Metal-on-metal hip articulations have been intensely debated after reports of adverse reactions and high failure rates. The aim of this study was to retrospectively evaluate the implant of a metal-on.metal total hip articulation (MOM THA) from a single manufacture in a two-center study. Materials and Methods: 108 CONSERVE® MOM THA were implanted in 92 patients between November 2005 and December 2010. Patients had at time of retrospective evaluation their journals reviewed for re-operations and adverse reactions. Results: 20 hips were re-operated (18.4%) at a mean follow up of 53 months. 4 pseudotumors were diagnosed at time of follow up but no substantiated link was made between adverse reactions and re-operations. Conclusion: The high re-operation rates found in this study raised concern about the usage of the MOM THA and subsequently lead to the termination of implantation of this MOM THA at the two orthopaedic departments. PMID:27099640

  5. Midterm results of 36 mm metal-on-metal total hip arthroplasty

    PubMed Central

    Akrawi, Hawar; Hossain, Fahad S; Niculescu, Stefan; Hashim, Zaid; Ng, Arron Biing; Shetty, Ajit

    2016-01-01

    Background: Despite the many perceived benefits of metal-on-metal (MoM) articulation in total hip arthroplasty (THA), there have been growing concerns about metallosis and adverse reaction to metal debris (ARMD). Analysis of size 36 mm MoM articulation THAs is presented. These patients were evaluated for patient characteristics, relationship between blood metal ions levels and the inclination as well as the version of acetabular component, cumulative survival probability at final followup and functional outcome at final followup. Materials and Methods: 288, size 36 mm MoM THAs implanted in 269 patients at our institution from 2004 to 2010 were included in this retrospective study. These patients were assessed clinically for hip symptoms, perioperative complications and causes of revision arthroplasty were analysed. Biochemically, blood cobalt and chromium metal ions level were recorded and measurements of acetabular inclination and version were examined. Radiological evaluation utilizing Metal Artefact Reduction Sequence (MARS) MRI was undertaken and implant cumulative survivorship was evaluated. Results: The mean followup was 5 years (range 2–7 years), mean age was 73 years and the mean Oxford hip score was 36.9 (range 5–48). Revision arthroplasty was executed in 20 (7.4%) patients, of which 15 patients underwent single-stage revision THA. The causes of revision arthroplasty were: ARMD changes in 6 (2.2%) patients, infection in 5 (1.9%) patients and aseptic loosening in 5 (1.9%) patients. Three (1.1%) patients had their hips revised for instability, 1 (0.3%) for raised blood metal ions levels. The implant cumulative survival rate, with revision for any reason, was 68.9% at 7 years. Conclusions: Although medium-sized MoM THA with a 36 mm head has a marginally better survivorship at midterm followup, compared to larger size head MoM articulating THA, our findings nonetheless are still worryingly poor in comparison to what has been quoted in the literature

  6. The temporal nature of forces acting on metal drops in gas metal arc welding

    SciTech Connect

    Jones, L.A.; Eagar, T.W.; Lang, J.H.

    1996-12-31

    At moderate and high welding currents, the most important forces in gas metal arc welding acting on the molten electrode are magnetic forces arising from the interaction between the welding current and its own magnetic field. These forces drive the dynamic evolution of the drop and also depend on the instantaneous shape of the drop. In this paper, experimentally observed manifestations of magnetic forces are shown, and a technique for approximating the temporal evolution of these forces from experimentally measured drop shapes is reported. The technique provides quantitative data illustrating the large increase in the magnetic forces as a drop detaches from the electrode.

  7. Understanding the differences between the wear of metal-on-metal and ceramic-on-metal total hip replacements.

    PubMed

    Figueiredo-Pina, C G; Yan, Y; Neville, A; Fisher, J

    2008-04-01

    Hip simulator studies have been carried out extensively to understand and test artificial hip implants in vitro as an efficient alternative to obtaining long-term results in vivo. Recent studies have shown that a ceramic-on-metal material combination lowers the wear by up to 100 times in comparison with a typical metal-on-metal design. The reason for this reduction remains unclear and for this reason this study has undertaken simple tribometer tests to understand the fundamental material loss mechanisms in two material combinations: metal-on-metal and ceramic-on-ceramic. A simple-configuration reciprocating pin-on-plate wear study was performed under open-circuit potential (OCP) and with applied cathodic protection (CP) in a serum solution using two tribological couples: firstly, cobalt-chromium (Co-Cr) pins against Co-Cr plates; secondly, Co-Cr pins against alumina (Al2O3) plates. The pin and plate surfaces prior to and after testing were examined by profilometry and scanning electron microscopy. The results showed a marked reduction in wear when CP was applied, indicating that total material degradation under the OCP condition was attributed to corrosion processes. The substitution of the Co-Cr pin with an Al2O3 plate also resulted in a dramatic reduction in wear, probably due to the reduction in the corrosion-wear interactions between the tribological pair. PMID:18491698

  8. 78 FR 14403 - Alabama Metal Coil Securement Act; Petition for Determination of Preemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-05

    ... System (FDMS) published in the Federal Register on December 29, 2010 (75 FR 82132). Background The Metal... Register on November 23, 2011 (76 FR 72495) seeking comment on whether the Act is preempted by Federal law... Federal Motor Carrier Safety Administration Alabama Metal Coil Securement Act; Petition for...

  9. Comparison of dissolved and total metals concentrations from acute tests with saltwater organisms

    SciTech Connect

    Lussier, S.M.; Boothman, W.S.; Champlin, D.; Poucher, S.; Helmstetten, A.

    1999-05-01

    Aquatic life criteria (ALC) have traditionally been expressed for meals in terms of total-recoverable or acid-soluble concentrations. Recent US Environmental protection Agency policy recommended use of dissolved metal concentrations for setting water quality standards. Criteria derived from previous tests could be expressed in terms of dissolved metals if ratios of dissolved-to-total concentrations in those tests were consistent. Using those metals with insufficient dissolved metals data to directly derive criteria (arsenic (III), cadmium, chromium (VI), lead, nickel, selenium (IV), and zinc), the authors measured both total and dissolved metal concentrations in acute saltwater static and flow-through tests. Exposure conditions simulated those of original tests used to derive ALC. Partitioning of metals between dissolved and particulate forms was very consistent. Dissolved metal concentrations were greater than 90% of total concentrations in all tests, exceeding 95% in 10 of 13 tests. Dissolved-to-total metal ratios did not vary significantly with concentration, time, or type of test. Biological responses were consistent with historical data. Results implied that in acute saltwater toxicity tests used to establish ALC, metals were primarily dissolved. Thus criteria developed for metals based on total concentrations should be equally valid when expressed in terms of dissolved concentrations.

  10. Poor short term outcome with a metal-on-metal total hip arthroplasty.

    PubMed

    Levy, Yadin D; Ezzet, Kace A

    2013-08-01

    Metal-on-metal (MoM) bearings for total hip arthroplasty (THA) have come under scrutiny with reports of high failure rates. Clinical outcome studies with several commercially available MoM THA bearings remain unreported. We evaluated 78 consecutive MoM THAs from a single manufacturer in 68 patients. Sixty-six received cobalt-chrome (CoCr) monoblock and 12 received modular titanium acetabular cups with internal CoCr liners. Femoral components were titanium with modular necks. At average 2.1 years postoperatively, 12 THAs (15.4%) demonstrated aseptic failure (10 revisions, 2 revision recommended). All revised hips demonstrated capsular necrosis with positive histology reaction for aseptic lymphocytic vasculitis-associated lesions/adverse local tissue reactions. Prosthetic instability following revision surgery was relatively common. Female gender was a strong risk factor for failure, though smaller cups were not. Both monoblock and modular components fared poorly. Corrosion was frequently observed around the proximal and distal end of the modular femoral necks. PMID:23538122

  11. Acute delayed infection: increased risk in failed metal on metal total hip arthroplasty.

    PubMed

    Prieto, Hernan A; Berbari, Elie F; Sierra, Rafael J

    2014-09-01

    Adverse local tissue reactions occurring in metal-on-metal total hip arthroplasty (MoM THA) could potentially lead to secondary failure modes such as dislocation or infection. The authors report a series of 124 patients treated with MoM hip arthroplasty between 2006 and 2010 with a minimum follow-up of 3 years. Eight hips presented with acute delayed or late periprosthetic joint infection (PJI) (defined as an infection occurring after 3 months in an otherwise well functioning implant). The rate of infection observed was higher than expected, almost 4 times higher (5.6%) compared to previous historical cohorts from our institution (1.3%). This high risk of infection in patients with DePuy ASR implants requires further study but we theorize that the increased prevalence of infection could be due to a combination of particulate debris, molecular (rather than particulate) effects of Co and Cr ions on soft tissues, and/or products of corrosion that may change the local environment predisposing to infection. PMID:24851788

  12. Dissolved:total metals concentrations in marine acute toxicity test simulations

    SciTech Connect

    Lussier, S.M.; Boothman, W.S.; Champlin, D.; Poucher, S.; Helmstetter, A.

    1995-12-31

    Use of water quality criteria expressed as dissolved metal is recommended by the US EPA, Office of Water, because ``dissolved metal more closely approximates the bioavailable fraction of metal in the water column than does total recoverable metal.`` Water quality criteria (WQC) are expressed in terms of total recoverable or acid-soluble metals concentrations; in part because few toxicity tests with aquatic organisms include measurement of dissolved metals. Therefore, if WQC are to be expressed as dissolved, complete retesting or derivation of dissolved:total (D:T) metals relationships to adjust existing criteria were required. To derive D:T ratios, simulated tests were conducted using concentrations and species similar to those used to derive original criteria. Dissolved (<0.45/{micro}) and total recoverable metals were measured to determine the partitioning relationship under these experimental conditions and convert criteria to reflect dissolved metals concentrations. Simulations were conducted with arsenic (III), cadmium, chromium (VI), lead, nickel, selenium, and zinc. In all simulations, average dissolved metals comprised 93--100% of total metals measured. Dissolved:total ratios did not significantly differ for a given metal throughout each test among test type or treatment concentration. Biological results, while insufficient to derive criteria directly, were generally consistent with results of historical biological response data. These results demonstrate that, under the conditions employed, i.e, short exposure periods (2--4 days) and low particulate load typical of these tests, metals are essentially not removed from solution onto particles. This does not imply that such partitioning is representative of conditions in natural waters, but rather that in the historical acute toxicity tests used to establish water quality criteria, metals were primarily dissolved.

  13. Perfusion MRI in hips with metal-on-metal and metal-on-polyethylene total hip arthroplasty

    PubMed Central

    Anwander, H.; Cron, G. O.; Rakhra, K.

    2016-01-01

    Objectives Hips with metal-on-metal total hip arthroplasty (MoM THA) have a high rate of adverse local tissue reactions (ALTR), often associated with hypersensitivity reactions. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) measures tissue perfusion with the parameter Ktrans (volume transfer constant of contrast agent). Our purpose was 1) to evaluate the feasibility of DCE-MRI in patients with THA and 2) to compare DCE-MRI in patients with MoM bearings with metal-on-polyethylene (MoP) bearings, hypothesising that the perfusion index Ktrans in hips with MoM THA is higher than in hips with MoP THA. Methods In this pilot study, 16 patients with primary THA were recruited (eight MoM, eight MoP). DCE-MRI of the hip was performed at 1.5 Tesla (T). For each patient, Ktrans was computed voxel-by-voxel in all tissue lateral to the bladder. The mean Ktrans for all voxels was then calculated. These values were compared with respect to implant type and gender, and further correlated with clinical parameters. Results There was no significant difference between the two bearing types with both genders combined. However, dividing patients by THA bearing and gender, women with MoM bearings had the highest Ktrans values, exceeding those of women with MoP bearings (0.067 min−1 versus 0.053 min−1; p-value < 0.05) and men with MoM bearings (0.067 min−1 versus 0.034 min−1; p-value < 0.001). Considering only the men, patients with MoM bearings had lower Ktrans than those with MoP bearings (0.034 min−1 versus 0.046 min−1; p < 0.05). Conclusion DCE-MRI is feasible to perform in tissues surrounding THA. Females with MoM THA show high Ktrans values in DCE-MRI, suggesting altered tissue perfusion kinematics which may reflect relatively greater inflammation. Cite this article: Dr P. E. Beaule. Perfusion MRI in hips with metal-on-metal and metal-on-polyethylene total hip arthroplasty: A pilot stud. Bone Joint Res 2016;5:73–79. DOI: 10

  14. Femoral Nerve Block Versus Long-Acting Wound Infiltration in Total Knee Arthroplasty.

    PubMed

    Emerson, Roger H; Barrington, John W; Olugbode, Oluseun; Lovald, Scott; Watson, Heather; Ong, Kevin

    2016-05-01

    Multimodal wound infiltration analgesic techniques have attracted growing interest for applications in total knee arthroplasty (TKA). A benefit of using wound infiltration instead of femoral nerve block (FNB) in a multimodal pain control regimen is the limitation of muscle strength impairment to the surgical area, which will focus the pain control effort and may provide the opportunity for easier rehabilitation and earlier discharge from the hospital. The current study directly compares patients undergoing TKA who are given a continuous FNB with those who were administered an injection of liposomal bupivacaine infiltration. The study cohort included 36 patients with osteoarthritis who were treated with a continuous FNB (OnQ pump; I-Flow, Lake Forest, California), and 36 patients who were administered an injection for liposome bupivacaine infiltration (EXPAREL; Pacira Pharmaceuticals, Inc, Parsippany, New Jersey) for postoperative pain analgesia. The average number of narcotic doses and the total number of narcotics consumed was greater in the FNB group (P<.001). Average visual analog scale pain scores trended higher for patients in the FNB group (2.29 vs 1.93) overall and for each day postoperatively up to day 5, although the overall difference was not significant in this study sample (P=.115). The results of the current study support the conclusion that long-acting liposome bupivacaine infiltration gives comparable postoperative analgesia compared with a continuous FNB, but with significantly less narcotic medication. [Orthopedics. 2016; 39(3):e449-e455.]. PMID:27018607

  15. Long-duration metal-on-metal total hip arthroplasties with low wear of the articulating surfaces.

    PubMed

    Schmalzried, T P; Peters, P C; Maurer, B T; Bragdon, C R; Harris, W H

    1996-04-01

    The 20-year performance of metal-on-metal hip articulations has not been reported. Five McKee-Farrar total hip prostheses and one Sivash prosthesis were obtained at revision surgery after a mean implantation time of 21.3 years. A radiographic, histologic, implant, and wear analysis was performed on these total hip implants with cobalt-chrome metal-on-metal articulations. All cases were associated with femoral component loosening, but the bearing surfaces performed remarkably well. The worst case estimate of combined femoral and acetabular linear wear was 4.2 microns per year, about 25 times less than that typically seen with polyethylene. Metal particles and foreign-body inflammation were seen in all cases, but the volume of reactive tissue was small compared with what is generally seen at revision of hips with a polyethylene acetabular bearing. This may be due to a reduced particle burden or a decreased inflammatory reaction to particulate metal, or both. In addition to articular wear, other sources of metal particles included femoral neck impingement on the acetabular rim, stem burnishing, and corrosion. Prosthetic hip reconstructions can fail for many reasons, including suboptimal femoral stem and/or acetabular cup design and/or fixation. By today's standards, the McKee-Farrar and Sivash stem and acetabular component designs are suboptimal; however, after more than 20 years of use, the metal-on-metal bearing surfaces in these cases demonstrated low wear and do not appear to be the cause of failure. Recent advances in total hip arthroplasty, which include improved implant design, materials, manufacturing, and fixation, combined with a better understanding of the mechanisms of implant loosening and failure, suggest that the cobalt-chrome metal-on-metal bearing be reexamined as an alternative to polyethylene when exceptional durability is required. PMID:8713913

  16. Cutaneous manifestation of metallosis in a metal-on-metal total hip arthroplasty after acetabular liner dissociation.

    PubMed

    Sporer, Scott M; Chalmers, Peter N

    2012-09-01

    In this case report, we describe a cutaneous manifestation of extensive metallosis in a patient 4 months post-metal-on-metal total hip arthroplasty with a Pinnacle cup with dissociation of the liner from the shell and resultant stripe burnishing of the shell and notch wear of the femoral neck. Dissociation of a metal liner has not been previously reported with this implant. Cutaneous metallosis has only been reported once in the literature. Clinicians should heighten their suspicion for metallosis secondary to hardware failure when encountering patients with skin discoloration in the setting of a painful and poorly functioning hip arthroplasty. In patients with failure of a metal-on-metal prosthesis with a modular metal liner in the acetabular component, liner dissociation must be considered. PMID:22397858

  17. Permeability of precious metals to hydrogen at 2kb total pressure and elevated temperatures.

    USGS Publications Warehouse

    Chou, I.-Ming

    1986-01-01

    Permeabilities of several commonly used precious metals to hydrogen have been measured at 2kb total pressure and between 450o and 812oC by using the double-capsule oxygen buffer technique.- from Author

  18. Effect of [Fe 2+/total metal] on treatment of heavy metals from laboratory wasteliquid by ferrite process

    NASA Astrophysics Data System (ADS)

    Huang, Yuh-Jeen; Tu, Chiu-Hui; Chien, Yi-Chi; Chen, Hung-Ta

    2006-11-01

    In this study, the X-ray absorption near-edge structure shows that poisonous Cr 6+ in the laboratory wasteliquid were reduced to Cr 3+ by adding Fe 2+ at [Fe 2+/total metal, mole ratio higher than 4:1. The X-ray diffraction analysis shows that greater the [Fe 2+/total metal] mole ratios used (such as 6:1, 10:1, 20:1 and 30:1), the more spinel-structured ferrites were formed (0.26, 0.30, 0.48 and 0.59). When [Fe 2+/total metal] mole ratio was larger than 20:1, the saturation magnetization and coercive field were about 5.21 emu/g and 6.2 kOe, respectively. The ferrite precipitates could be recovered as magnitude materials. However, the TCLP test result was beyond the standard of EPA when the [Fe 2+/total metal] mole ratio was 30:1. The optimum operation for the laboratory wasteliquid by ferrite process in the [Fe 2+/total metal] mole ratio was 20:1.

  19. 50 CFR 648.231 - Spiny dogfish Annual Catch Target (ACT) and Total Allowable Level of Landings (TAL).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) and Total Allowable Level of Landings (TAL). 648.231 Section 648.231 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES... dogfish Annual Catch Target (ACT) and Total Allowable Level of Landings (TAL). (a) The Spiny...

  20. 50 CFR 648.231 - Spiny dogfish Annual Catch Target (ACT) and Total Allowable Level of Landings (TAL).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) and Total Allowable Level of Landings (TAL). 648.231 Section 648.231 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES... dogfish Annual Catch Target (ACT) and Total Allowable Level of Landings (TAL). (a) The Spiny...

  1. Removal of trabecular metal osteonecrosis intervention implant and conversion to primary total hip arthroplasty.

    PubMed

    Owens, Joshua B; Ely, Erin E; Guilliani, Nathania M Figueroa; Suarez, Juan C; Patel, Preetesh D

    2012-06-01

    Core decompression and placement of the Trabecular Metal Osteonecrosis Intervention Implant have shown to be initially successful in treating early osteonecrosis. When treatment fails, however, patients often undergo primary total hip arthroplasty (THA) requiring removal of a previously inserted trabecular metal implant. We describe a technical tip for removal of a well-ingrown trabecular metal screw. A metal-cutting trephine placed over the screw allows for removal in an efficient manner while minimizing additional dissection and bone loss during conversion to THA. PMID:22425306

  2. Fast-acting self-healing metallic fuse.

    NASA Technical Reports Server (NTRS)

    Schwartz, F. C.; Renton, C. A.; Rabinovici, B.

    1971-01-01

    Description of a fast-acting nonmechanical self-healing mercury fuse capable of protecting a high current circuit or device from overcurrent fault damages. Basically the self-healing fuse consists of two enclosed mercury reservoirs connected by a fine capillary tube filled with mercury that serves as the fusing element. It is pointed out that a better understanding of the energy conversion process involved in the operation of the device could help explore other device configurations (such as a tapering geometry and use of magnetic field to drive the arc into the fuse wall on inductive loads, etc.) and thus extend the range of capabilities for this type of protective device.

  3. Metal block augmentation for bone defects of the medial tibia during primary total knee arthroplasty

    PubMed Central

    2013-01-01

    Background Stable and well-aligned placement of tibial components during primary total knee arthroplasty is challenging in patients with bone defects. Although rectangular block-shaped augmentations are widely used to reduce the shearing force between the tibial tray and bone compared with wedge-shaped augmentations, the clinical result remains unclear. This study aimed to evaluate the outcome of primary total knee arthroplasty with metal block augmentation. Methods We retrospectively reviewed the 3- to 6-year follow-up results of 33 knees that underwent total knee arthroplasty with metal block augmentation (metal-augmented group) for bone defects of the medial tibia and 132 varus knees without bone defects as the control group. All surgeries were performed using posterior-stabilized cemented prostheses in both groups. Cemented stems were routinely augmented when the metal block was used. Results There were no differences in implant survival rates (100% in metal-augmented and 99.2% in control) or knee function scores (82 points in metal-augmented and 84 points in control) between the two groups at the final follow-up examination (P = 0.60 and P = 0.09, respectively). No subsidence or loosening of the tibial tray was observed. Of 33 metal-augmented total knee arthroplasties, a nonprogressive radiolucent line beneath the metal was detected in 10 knees (30.3%), and rounding of the medial edge of the tibia was observed in 17 knees (51.5%). Conclusions The clinical results of total knee arthroplasty with metal augmentation were not inferior to those in patients without bone defects. However, radiolucent lines were observed in 30.3%. PMID:24139483

  4. Gender is a significant factor for failure of metal-on-metal total hip arthroplasty.

    PubMed

    Latteier, Michael J; Berend, Keith R; Lombardi, Adolph V; Ajluni, Andrew F; Seng, Brian E; Adams, Joanne B

    2011-09-01

    Metal-on-metal (MoM) articulations offers low wear, larger head size, and increased stability. Reports of early failure are troubling and include failure of ingrowth and metal articulation problems such as metallosis, hypersensitivity, pseudotumor, and unexplained pain. This study investigates the survivorship of modern MoM articulations by gender. We reviewed 1589 primary MoM THA in 1363 patients, with minimum 2-year follow-up for 1212 hips. Follow-up averaged 60 months. There were 643 female patients and 719 male patients. The incidence of cup revision was significantly higher in women than in men (8.2% vs 2.7%; P = .0000), as was incidence of aseptic loosening (4.3% vs 1.1%; P = .0006), and failure for metal-bearing complications (2.2% vs 0.6%; P = .0126). There appear to be gender factors influencing the success of MoM THA, which may include hormonal, anatomic, or functional differences. PMID:21641761

  5. Serum Metal Ion Concentrations in Paediatric Patients following Total Knee Arthroplasty Using Megaprostheses

    PubMed Central

    Friesenbichler, Jörg; Sadoghi, Patrick; Maurer-Ertl, Werner; Szkandera, Joanna; Glehr, Mathias; Ogris, Kathrin; Wolf, Matthias; Weger, Christian; Leithner, Andreas

    2014-01-01

    The purpose of this study was to determine the concentrations of cobalt, chromium, and molybdenum in the serum of paediatric tumour patients after fixed hinge total knee arthroplasty. Further, these metal ion levels were compared with serum metal ion levels of patients with other orthopaedic devices such as hip and knee prostheses with metal-on-metal or metal-on-polyethylene articulation to find differences between anatomical locations, abrasion characteristics, and bearing surfaces. After an average follow-up of 108 months (range: 67 to 163) of 11 paediatric patients with fixed hinge total knee arthroplasty, the mean concentrations for Co and Cr were significantly increased while Mo was within the limits compared to the upper values from the reference laboratory. Furthermore, these serum concentrations were significantly higher compared to patients with a standard rotating hinge device (P = 0.002 and P < 0.001) and preoperative controls (P < 0.001). On the other hand, the serum levels of patients following MoM THA or rotating hinge arthroplasty using megaprostheses were higher. Therefore, periodic long-term follow-ups are recommended due to the rising concerns about systemic metal ion exposure in the literature. Upon the occurrence of adverse reactions to metal debris the revision of the fixed hinge implant should be considered. PMID:25276819

  6. Screening for symptomatic metal sensitivity: a prospective study of 92 patients undergoing total knee arthroplasty.

    PubMed

    Niki, Yasuo; Matsumoto, Hideo; Otani, Toshiro; Yatabe, Taku; Kondo, Makoto; Yoshimine, Fumihiro; Toyama, Yoshiaki

    2005-03-01

    Metal sensitivity (MS) reactions to implant metals represent a rare but well-documented complication following total joint arthroplasty (TJA). Although 20-25% of post-TJA patients develop MS, only a few highly susceptible patients (< 1%) exhibit symptoms. Whether surgeons should perform screening for MS is currently a matter of debate. The present study investigated the clinical importance of screening for patients predisposed to symptomatic MS, and the specific metals causing symptomatic MS following total knee arthroplasty (TKA). Between 2000 and 2002, a total of 108 primary TKAs were performed on 92 patients. Preoperatively, all patients underwent modified lymphocyte stimulation test (mLST) to Ni, Co, Cr, and Fe. Of the 92 patients, 24 (26%) displayed positive preoperative responses to at least one metal. Five patients displayed implant metal-related eczema and were all mLST-positive preoperatively, suggesting that screening for symptomatic MS is clinically useful. Two of these underwent revision TKA and thereafter, eczema healed and mLST results changed from positive to negative. All mLST-positive patients were divided into three groups: Group I, patients with eczema; Group II, patients with clear history of MS; and Group III, patients neither eczema nor history of MS. When the type of sensitive metals were compared among the three groups, a significant association between presence of Cr-sensitivity and development of eczema (P < 0.05) was identified. No significant association was observed between other metals and development of eczema or history of MS. This indicates that Cr is a potential candidate metal for causing eczema in our TKA series, and Cr-sensitivity may offer a potential predictor for symptomatic MS. The present study indicates that the surgeons should undertake routine preoperative screening for MS, particularly to Cr. PMID:15369690

  7. Exposure assessment of metal intakes from drinking water relative to those from total diet in Japan.

    PubMed

    Ohno, Koichi; Ishikawa, Kohei; Kurosawa, Yuki; Matsui, Yoshihiko; Matsushita, Taku; Magara, Yasumoto

    2010-01-01

    Daily intakes of 17 metals (boron, aluminium, chromium, manganese, nickel, copper, zinc, arsenic, selenium, molybdenum, cadmium, antimony, lead, uranium, magnesium, calcium, and iron) via drinking water and total diet were investigated in six cities in Japan. The daily metal intakes were estimated and compared with tolerable daily intake (TDI) values proposed by the WHO or Joint FAO/WHO Expert Committee on Food Additives for toxic metals and with recommended dietary allowances (RDAs) or adequate intake (AI) values proposed for essential metals by the Japanese Ministry of Health, Labour and Welfare. Among the 13 toxic metals, mean dietary intakes of 10 (except arsenic, selenium, and molybdenum) were less than 50% of TDI, suggesting that for these 10 metals the allocation of intake to drinking water in establishing guidelines or standards could possibly be increased from the normal allocation of 10-20% of TDI. For the 13 toxic metals, the contribution of drinking water to TDI was 2% or less in all six cities. Mean dietary intakes of the essential elements magnesium, calcium, and iron were less than the RDA or AI values. Drinking water did not contribute much to essential metal intake, accounting for less than 10% of RDA or AI. PMID:21099058

  8. A hydrometallurgical process for recovering total metal values from waste monolithic ceramic capacitors.

    PubMed

    Prabaharan, G; Barik, S P; Kumar, B

    2016-06-01

    A hydrometallurgical process for recovering the total metal values from waste monolithic ceramic capacitors was investigated. The process parameters such as time, temperature, acid concentration, hydrogen peroxide concentration and other reagents (amount of zinc dust and sodium formate) were optimized. Base metals such as Ba, Ti, Sn, Cu and Ni are leached out in two stages using HCl in stage 1 and HCl with H2O2 in stage 2. More than 99% of leaching efficiency for base metals (Cu, Ni, Ba, Ti and Sn) was achieved. Precious metals such as Au and Pd are leached out using aquaregia and nitric acid was used for the leaching of Ag. Base metals (Ba, Ti, Sn, Cu and Ni) are recovered by selective precipitation using H2SO4 and NaOH solution. In case of precious metals, Au and Pd from the leach solution were precipitated out using sodium metabisulphite and sodium formate, respectively. Sodium chloride was used for the precipitation of Ag from leach solution. Overall recovery for base metals and precious metals are 95% and 92%, respectively. Based on the results of the present study, a process flow diagram was proposed for commercial application. PMID:27084106

  9. 50 CFR 648.231 - Spiny dogfish Annual Catch Target (ACT) and Total Allowable Level of Landings (TAL).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Spiny dogfish Annual Catch Target (ACT) and Total Allowable Level of Landings (TAL). 648.231 Section 648.231 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE NORTHEASTERN UNITED...

  10. 77 FR 30280 - Clean Water Act Section 303(d): Withdrawal of Nine Total Maximum Daily Loads (TMDLs)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-22

    ... AGENCY Clean Water Act Section 303(d): Withdrawal of Nine Total Maximum Daily Loads (TMDLs) AGENCY... (see 76 FR 52947) which pertain to segments 08040203-010, 08040204-006, and 08040206-015, -016, -716... comments on the draft TMDLs, was published on December 17, 2007 (see 72 FR 71409). Public comments...

  11. 75 FR 8698 - Clean Water Act Section 303(d): Availability of Ten Total Maximum Daily Loads (TMDLs) in Louisiana

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-25

    ... AGENCY Clean Water Act Section 303(d): Availability of Ten Total Maximum Daily Loads (TMDLs) in Louisiana..., Water Quality Protection Division, U.S. Environmental Protection Agency Region 6, 1445 Ross Ave., Dallas... State three-mile limit. EPA requests the public provide to EPA any water quality related data...

  12. 76 FR 77226 - Clean Water Act Section 303(d): Availability of 28 Total Maximum Daily Loads (TMDLs) in Louisiana

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-12

    ... AGENCY Clean Water Act Section 303(d): Availability of 28 Total Maximum Daily Loads (TMDLs) in Louisiana... that published on November 14, 2011, 76 FR 70442 (FRL-9491-1). Specifically, comments will be accepted... 28 TMDLs should be sent to Diane Smith, Environmental Protection Specialist, Water Quality...

  13. 77 FR 18809 - Clean Water Act Section 303(d): Proposed Withdrawal of Nine Total Maximum Daily Loads (TMDLs)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... AGENCY Clean Water Act Section 303(d): Proposed Withdrawal of Nine Total Maximum Daily Loads (TMDLs... not affect seven final TMDLs published under the same Federal Register notice (see 76 FR 52947) which... availability, seeking public comments on the draft TMDLs, was published on December 17, 2007 (see 72 FR...

  14. Metal-backed and all-polyethylene tibial components in total knee replacement.

    PubMed

    Rodriguez, J A; Baez, N; Rasquinha, V; Ranawat, C S

    2001-11-01

    One hundred seventy-five patients with 243 consecutive primary Press Fit Condylar cruciate-substituting total knee replacements were evaluated at a mean of 5.5 years. One hundred thirteen knees had modular metal-backed tibial components and 130 had all-polyethylene tibial components. The mean knee score and functional score for the patients with unrevised components was not significantly different. The incidence of osteolysis and synovitis was higher in patients in the modular metal-backed tibia group (5%; five patients, six knees). No patients in the all-polyethylene tibia group had osteolysis or synovitis. Five revision operations were necessary: four for osteolytic defects and one for synovitis, all in patients in the modular metal-backed tibia group. All of the retrieved polyethylene inserts had evident backside wear. The best case rate of survival of the all-polyethylene tibial components was 96%+/-0.8% at 7 years and for the modular metal-backed components it was 75%+/-10% at 7 years. Metal backing and modularity were added to the Press Fit Condylar total knee replacement design to improve fixation durability. However, the superiority of the modular metal-backed implants remains in question. PMID:11716380

  15. Mid-term results of a metal-backed glenoid component in total shoulder replacement.

    PubMed

    Castagna, A; Randelli, M; Garofalo, R; Maradei, L; Giardella, A; Borroni, M

    2010-10-01

    Total shoulder replacement is a successful procedure for degenerative or some inflammatory diseases of the shoulder. However, fixation of the glenoid seems to be the main weakness with a high rate of loosening. The results using all-polyethylene components have been better than those using metal-backed components. We describe our experience with 35 consecutive total shoulder replacements using a new metal-backed glenoid component with a mean follow-up of 75.4 months (48 to 154). Our implant differs from others because of its mechanism of fixation. It has a convex metal-backed bone interface and the main stabilising factor is a large hollow central peg. The patients were evaluated with standard radiographs and with the Constant Score, the Simple Shoulder Test and a visual analogue scale. All the scores improved and there was no loosening, no polyethylene-glenoid disassembly and no other implant-related complications. We conclude that a metal-backed glenoid component is a good option in total shoulder replacement with no worse results than of those using a cemented all-polyethylene prosthesis. PMID:20884980

  16. Size of metallic and polyethylene debris particles in failed cemented total hip replacements

    NASA Technical Reports Server (NTRS)

    Lee, J. M.; Salvati, E. A.; Betts, F.; DiCarlo, E. F.; Doty, S. B.; Bullough, P. G.

    1992-01-01

    Reports of differing failure rates of total hip prostheses made of various metals prompted us to measure the size of metallic and polyethylene particulate debris around failed cemented arthroplasties. We used an isolation method, in which metallic debris was extracted from the tissues, and a non-isolation method of routine preparation for light and electron microscopy. Specimens were taken from 30 cases in which the femoral component was of titanium alloy (10), cobalt-chrome alloy (10), or stainless steel (10). The mean size of metallic particles with the isolation method was 0.8 to 1.0 microns by 1.5 to 1.8 microns. The non-isolation method gave a significantly smaller mean size of 0.3 to 0.4 microns by 0.6 to 0.7 microns. For each technique the particle sizes of the three metals were similar. The mean size of polyethylene particles was 2 to 4 microns by 8 to 13 microns. They were larger in tissue retrieved from failed titanium-alloy implants than from cobalt-chrome and stainless-steel implants. Our results suggest that factors other than the size of the metal particles, such as the constituents of the alloy, and the amount and speed of generation of debris, may be more important in the failure of hip replacements.

  17. The Use of Trabecular Metal Cones in Complex Primary and Revision Total Knee Arthroplasty.

    PubMed

    Brown, Nicholas M; Bell, Joshua A; Jung, Edward K; Sporer, Scott M; Paprosky, Wayne G; Levine, Brett R

    2015-09-01

    Trabecular metal cones are one option for treating osseous defects during TKA. A total of 83 consecutive TKAs utilizing cones with an average of 40 months follow-up were reviewed. There were 24 males and 59 females, with an average age of 69 years old. Four were complex primary and 79 were revision procedures. Of 83 patients, 10 (12%) required repeat revision surgery (8 infections, one periprosthetic fracture, one aseptic loosening) and overall, 37 of 83 patients (45%) experienced at least one complication. Of 73 unrevised knees, 72 (99%) demonstrated radiographic evidence of osseointegration. Despite a high complication rate in this population, trabecular metal cones represent an attractive option for managing bone loss in complex primary and revision TKA with a high rate of osseointegration. PMID:26100475

  18. Particle characterisation and cytokine expression in failed small-diameter metal-on-metal total hip arthroplasties.

    PubMed

    Singh, G; Nuechtern, J V; Meyer, H; Fiedler, G M; Awiszus, F; Junk-Jantsch, S; Bruegel, M; Pflueger, G; Lohmann, C H

    2015-07-01

    The peri-prosthetic tissue response to wear debris is complex and influenced by various factors including the size, area and number of particles. We hypothesised that the 'biologically active area' of all metal wear particles may predict the type of peri-prosthetic tissue response. Peri-prosthetic tissue was sampled from 21 patients undergoing revision of a small diameter metal-on-metal (MoM) total hip arthroplasty (THA) for aseptic loosening. An enzymatic protocol was used for tissue digestion and scanning electron microscope was used to characterise particles. Equivalent circle diameters and particle areas were calculated. Histomorphometric analyses were performed on all tissue specimens. Aspirates of synovial fluid were collected for analysis of the cytokine profile analysis, and compared with a control group of patients undergoing primary THA (n = 11) and revision of a failed ceramic-on-polyethylene arthroplasty (n = 6). The overall distribution of the size and area of the particles in both lymphocyte and non-lymphocyte-dominated responses were similar; however, the subgroup with lymphocyte-dominated peri-prosthetic tissue responses had a significantly larger total number of particles. 14 cytokines (interleukin (IL)-1ß, IL-2, IL-4, IL-5, IL-6, IL-10, IL-13, IL-17, interferon (IFN)-γ, and IFN-gamma-inducible protein 10), chemokines (macrophage inflammatory protein (MIP)-1α and MIP-1ß), and growth factors (granulocyte macrophage colony stimulating factor (GM-CSF) and platelet derived growth factor) were detected at significantly higher levels in patients with metal wear debris compared with the control group. Significantly higher levels for IL-1ß, IL-5, IL-10 and GM-CSF were found in the subgroup of tissues from failed MoM THAs with a lymphocyte-dominated peri-prosthetic response compared with those without this response. These results suggest that the 'biologically active area' predicts the type of peri-prosthetic tissue response. The cytokines IL-1ß, IL-5

  19. Mortality rates at 10 years after metal-on-metal hip resurfacing compared with total hip replacement in England: retrospective cohort analysis of hospital episode statistics

    PubMed Central

    Kendal, Adrian R; Prieto-Alhambra, Daniel; Arden, Nigel K; Judge, Andrew

    2013-01-01

    Objectives To compare 10 year mortality rates among patients undergoing metal-on-metal hip resurfacing and total hip replacement in England. Design Retrospective cohort study. Setting English hospital episode statistics database linked to mortality records from the Office for National Statistics. Population All adults who underwent primary elective hip replacement for osteoarthritis from April 1999 to March 2012. The exposure of interest was prosthesis type: cemented total hip replacement, uncemented total hip replacement, and metal-on-metal hip resurfacing. Confounding variables included age, sex, Charlson comorbidity index, rurality, area deprivation, surgical volume, and year of operation. Main outcome measures All cause mortality. Propensity score matching was used to minimise confounding by indication. Kaplan-Meier plots estimated the probability of survival up to 10 years after surgery. Multilevel Cox regression modelling, stratified on matched sets, described the association between prosthesis type and time to death, accounting for variation across hospital trusts. Results 7437 patients undergoing metal-on-metal hip resurfacing were matched to 22 311 undergoing cemented total hip replacement; 8101 patients undergoing metal-on-metal hip resurfacing were matched to 24 303 undergoing uncemented total hip replacement. 10 year rates of cumulative mortality were 271 (3.6%) for metal-on-metal hip resurfacing versus 1363 (6.1%) for cemented total hip replacement, and 239 (3.0%) for metal-on-metal hip resurfacing versus 999 (4.1%) for uncemented total hip replacement. Patients undergoing metal-on-metal hip resurfacing had an increased survival probability (hazard ratio 0.51 (95% confidence interval 0.45 to 0.59) for cemented hip replacement; 0.55 (0.47 to 0.65) for uncemented hip replacement). There was no evidence for an interaction with age or sex. Conclusions Patients with hip osteoarthritis undergoing metal-on-metal hip resurfacing have reduced mortality in

  20. Metal release and corrosion effects of modular neck total hip arthroplasty

    PubMed Central

    Jakubowitz, Eike; Krachler, Michael; Thomsen, Marc; Heisel, Christian

    2009-01-01

    Modular neck implants are an attractive treatment tool in total hip replacement. Concerns remain about the mechanical stability and metal ion release caused by the modular connection. Five different implant designs were investigated in an experimental set-up. In vivo conditions were simulated and the long-term titanium release was measured. Finally, the modular connections were inspected for corrosion processes and signs of fretting. No mechanical failure or excessive corrosion could be identified for the implants tested. The titanium releases measured were extremely low compared to in vivo and in vitro studies and were not in a critical range. PMID:19219434

  1. Relationship between elemental carbon, total carbon, and diesel particulate matter in several underground metal/non-metal mines.

    PubMed

    Noll, J D; Bugarski, A D; Patts, L D; Mischler, S E; McWilliams, L

    2007-02-01

    Elemental carbon (EC) is currently used as a surrogate for diesel particulate matter (DPM) in underground mines since it can be accurately measured at low concentrations and diesels are the only source of submicrometer EC in underground mines. A disadvantage of using EC as a surrogate for DPM is that the fraction of EC in DPM is a function of various engine parameters and fuel formulations, etc. In order to evaluate how EC predicts DPM in the underground mining atmosphere, measurements of total carbon (TC; representing over 80% of the DPM) and EC were taken away from potential interferences in four underground metal/non-metal mines during actual production. In a controlled atmosphere, DPM mass, TC, and EC measurements were also collected while several different types of vehicles simulated production with and without different types of control technologies. When diesel particulate filters (DPFs) were not used, both studies showed that EC could be used to predict DPM mass or TC. The variability of the data started to increase at TC concentrations below 230 microg/m3 and was high (> +/- 20%) at TC concentrations below 160 microg/m3, probably due to the problem with sampling organic carbon (OC) at these concentrations. It was also discovered that when certain DPFs were used, the relationship between DPM and EC changed at lower DPM concentrations. PMID:17333567

  2. Measurements of Total Hemispherical Emissivity of Several Stably Oxidized Metals and Some Refractory Oxide Coatings

    NASA Technical Reports Server (NTRS)

    Wade, William R.

    1959-01-01

    A description of the apparatus and methods used for obtaining total hemispherical emissivity is presented, and data for several stably oxidized metals are included. The metals which were tested included type 347 stainless steel, tungsten, and Haynes alloys B, C, X, and 25. No values of emissivity were obtained for tungsten or Haynes alloy B because of the nature of the oxides produced. The refractory oxide coatings tested were flame-sprayed alumina and zirconia. The results of the investigation indicate that strongly adherent, oxidized surfaces of a high stable emissivity can be produced on type 347 stainless steel for which the total hemispherical emissivity varied from 0.87 to 0.91 for temperatures from 600 F to 2,000 F. For this same temperature range, the Haynes alloys tested showed values of total hemispherical emissivity from 0.90 to 0.96 for alloy C, from 0.85 to 0.88 for alloy X, and from 0.85 to 0.89 for alloy 25. Haynes alloy B and tungsten formed nonadherent oxides at elevated temperatures and, therefore, stable emissivities were not obtained. The results obtained for the flame-sprayed ceramics (alumina and zirconia) showed considerably higher values of total emissivity than those measured for coatings applied by other methods. Emissivity values ranging from 0.69 to 0.44 for aluminum oxide and from 0.62 to 0.44 for zirconium oxide were measured for temperatures from 800 F to 2,000 F.

  3. Comparison of synovial fluid, urine, and serum ion levels in metal-on-metal total hip arthroplasty at a minimum follow-up of 18 years.

    PubMed

    Lass, Richard; Grübl, Alexander; Kolb, Alexander; Stelzeneder, David; Pilger, Alexander; Kubista, Bernd; Giurea, Alexander; Windhager, Reinhard

    2014-09-01

    Diagnosis of adverse reactions to metal debris in metal-on-metal hip arthroplasty is a multifactorial process. Systemic ion levels are just one factor in the evaluation and should not be relied upon solely to determine the need for revision surgery. Furthermore, the correlation between cobalt or chromium serum, urine, or synovial fluid levels and adverse local tissue reactions is still incompletely understood. The hypothesis was that elevated serum and urine metal-ion concentrations are associated with elevated local metal-ion concentrations in primary total hip arthroplasties (THA) and with failure of metal-on-metal articulations in the long-term. In our present study, we evaluated these concentrations in 105 cementless THA with metal-on-metal articulating surfaces with small head diameter at a minimum of 18 years postoperatively. Spearman correlation showed a high correlation between the joint fluid aspirate concentration of cobalt and chromium with the serum cobalt (r = 0.81) and chromium level (r = 0.77) in patients with the THA as the only source of metal-ions. In these patients serum metal-ion analysis is a valuable method for screening. In patients with more than one source of metal or renal insufficiency additional investigations, like joint aspirations are an important tool for evaluation of wear and adverse tissue reactions in metal-on-metal THA. PMID:24841922

  4. Heavy metals and acidic components in total deposited matter in Sibenik and National Park Kornati, Croatia.

    PubMed

    Cacković, Mirjana; Kalinić, Natasa; Vadjić, Vladimira; Pehnec, Gordana

    2009-01-01

    This article presents the results of 6 years (1999-2004) of monitoring acidic components (fluoride, chloride, nitrate, sulfate) and heavy metals (lead, cadmium, thallium) in total deposited matter (TDM) in the town of Sibenik and the National Park Kornati, Croatia, in order to determine their levels, spatial and temporal variations, and possible emission source. Bulk deposition samples were collected using the Bergerhoff samplers. TDM matter was determined gravimetrically. Acidic anions were analyzed using ion chromatography. Metallic components were determined by atomic absorption spectrometry. Results show that the levels of measured pollutants were relatively low compared to those reported in other investigations. Statistical analysis indicates that the measured pollutants originate from several sources such as resuspended soil, industry, road dust, traffic, and secondary aerosols as the most important. The levels of TDM show a slightly increasing trend at all sampling sites. A significant increasing trend in the levels of nitrate and sulfate in TDM could be the consequence of increasing traffic activity and urbanization. The significant increasing trend in the ratio between nitrate and sulfate in TDM indicates that the nitrate and sulfate relative contribution to acidification is increasing. The level of heavy metals in TDM was in order of lead > thallium > cadmium at all sampling sites with slightly decreasing trend. PMID:18414927

  5. Spectral and total temperature-dependent emissivities of few-layer structures on a metallic substrate.

    PubMed

    Blandre, Etienne; Chapuis, Pierre-Olivier; Vaillon, Rodolphe

    2016-01-25

    We investigate the thermal radiative emission of few-layer structures deposited on a metallic substrate and its dependence on temperature with the Fluctuational Electrodynamics approach. We highlight the impact of the variations of the optical properties of metallic layers on their temperature-dependent emissivity. Fabry-Pérot spectral selection involving at most two transparent layers and one thin reflective layer leads to well-defined peaks and to the amplification of the substrate emission. For a single Fabry-Pérot layer on a reflective substrate, an optimal thickness that maximizes the emissivity of the structure can be determined at each temperature. A thin lossy layer deposited on the previous structure can enhance interference phenomena, and the analysis of the participation of each layer to the emission shows that the thin layer is the main source of emission. Eventually, we investigate a system with two Fabry-Pérot layers and a metallic thin layer, and we show that an optimal architecture can be found. The total hemispherical emissivity can be increased by one order of magnitude compared to the substrate emissivity. PMID:26832589

  6. Trace metal determination in total atmospheric deposition in rural and urban areas.

    PubMed

    Azimi, Sam; Ludwig, Alexandre; Thévenot, Daniel R; Colin, Jean-Louis

    2003-06-01

    The wet, dry and total atmospheric depositions of some metals (Al, Cd, Cr, Cu, Fe, Na, Pb and Zn) were sampled at two sites and atmospheric fallout fluxes were determined for these locations. This work, led by two different research groups, allowed to reach two main goals: to define a simple analytical procedure to secure accurate shipboard sampling and analysis of atmospheric deposition, and to assess anthropogenic impacts of heavy metals to the environment. The first step about the validation step showed that the prevalent deposition type was dry deposition which represents 40, 60 and 80% for Cd, Cu and Pb, respectively. This prevalence of dry deposition in total atmospheric fallout supported the necessity of funnel wall rinsing which contains 30, 50 and 40% of collected Cd, Cu and Pb, respectively. Moreover, the reproducibility of atmospheric deposition collection was determined. The second step was performed by comparing two sampling sites. A rural sampling site, situated in Morvan's regional park (250 km south-east of Paris), was chosen for its isolation from any local and regional contamination sources. Fluxes obtained in this area were compared with those obtained at an urban site (Créteil, suburb of Paris) allowing comparison between urban and rural areas and demonstrating the impact of anthropogenic activities on atmospheric deposition of Cr, Cu and Pb. PMID:12738217

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

    PubMed

    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. PMID:25980556

  8. Radiological Stability after Revision of Infected Total Knee Arthroplasty Using Modular Metal Augments

    PubMed Central

    Lee, Kyung-Jae; Cho, Chul-Hyun; Son, Eun-Seok; Jung, Jae-Won

    2016-01-01

    Purpose To evaluate the radiological stability according to the number of modular augments after revision of infected total knee arthroplasty (TKA). Materials and Methods Between February 2006 and September 2013, 37 patients (39 knees) followed ≥2 years after revision of infected TKA using modular metal augments for bone defects were reviewed retrospectively. We divided the patients into 3 groups according to the number of augments into group A (≤2 augments, 14 knees), group B (3–4 augments, 18 knees), and group C (5≥ augments, 7 knees) and evaluated the width of radiolucent zones around the implant at the last follow-up. Results There were 3 Anderson Orthopedic Research Institute type I, 33 type II, and 3 type III bone defects. The mean number of radiolucent zones of group A was 3 and the sum of width averaged 4.4 mm. In group B, the values were 4.8 and 6.2 mm, respectively. In group C, the values were 8.1 and 12.9 mm, respectively. The differences between the three groups were statistically significant. Conclusions In revision TKA with modular metal augmentation caused by infected TKA, increased modularity can result in radiological instability. PMID:26955613

  9. Exposures to inhalable and "total" oil mist aerosol by metal machining shop workers.

    PubMed

    Wilsey, P W; Vincent, J H; Bishop, M J; Brosseau, L M; Greaves, I A

    1996-12-01

    Several recent studies have compared worker personal aerosol exposures as measured by the current method with those obtained by a new approach based on collecting the inhalable fraction, intended to represent all the particles that are capable of entering through the nose and/or mouth during breathing. The present study investigated this relationship for a metal machining facility where aerosols were generated from severely refined, nonaqueous ("straight") cutting oils used during the lathe working of metal rod stock. Workers (n = 23) wore two personal aerosol samplers simulataneously, one of the 37-mm type (for "total" aerosol exposure, E37) and the other of the Institute of Occupational Medicine (IOM) type (for inhalable aerosol exposure, EIOM). The data were analyzed by weighted least squares linear regression to determine the coefficient S in the relation EIOM = S.E37. It was found that S = 2.96 +/- 0.60. This ratio-in which exposure to inhalable aerosol was greater than to "total" aerosol-is consistent with previous observations in other industries. The relative coarsenss of the oil mist aerosol, as estimated by cascade impactor measurements, probably explains the difference between the sampling methods. The collection of large "splash" droplets, may also contribute. Future occupational aerosol standards for metalworking fluids will be based on the new, health-related criteria, and exposures will be assessed on the basis of the inhalable fraction. Results of studies like that described here will enable assessment of the impact on future workplace aerosol exposure assessments of introducing new standards. PMID:8976589

  10. Adverse reaction to metal debris after ReCap-M2A-Magnum large-diameter-head metal-on-metal total hip arthroplasty

    PubMed Central

    2013-01-01

    Background and purpose The clinical findings of adverse reaction to metal debris (ARMD) following large-diameter-head metal-on-metal total hip arthroplasty (LDH MoM THA) may include periarticular fluid collections, soft tissue masses, and gluteal muscle necrosis. The ReCap-M2a-Magnum LDH MoM THA was the most commonly used hip device at our institution from 2005 to 2012. We assessed the prevalence of and risk factors for ARMD with this device. Methods 74 patients (80 hips) had a ReCap-M2a-Magnum LDH MoM THA during the period August 2005 to December 2006. These patients were studied with hip MRI, serum chromium and cobalt ion measurements, the Oxford hip score questionnaire, and by clinical examination. The prevalence of ARMD was recorded and risk factors for ARMD were assessed using logistic regression models. The mean follow-up time was 6.0 (5.5–6.7) years. Results A revision operation due to ARMD was needed by 3 of 74 patients (3 of 80 hips). 8 additional patients (8 hips) had definite ARMD, but revision was not performed. 29 patients (32 hips) were considered to have a probable or possible ARMD. Altogether, 43 of 80 hips had a definite, probable, or possible ARMD and 34 patients (37 hips) were considered not to have ARMD. In 46 of 78 hips, MRI revealed a soft tissue mass or a collection of fluid (of any size). The symptoms clicking in the hip, local hip swelling, and a feeling of subluxation were associated with ARMD. Interpretation ARMD is common after ReCap-M2a-Magnum total hip arthroplasty, and we discourage the use of this device. Asymptomatic patients with a small fluid collection on MRI may not need instant revision surgery but must be followed up closely. PMID:24171688

  11. Effect of acanthocephalan infection on metal, total protein and metallothionein concentrations in European chub from a Sava River section with low metal contamination.

    PubMed

    Filipović Marijić, Vlatka; Vardić Smrzlić, Irena; Raspor, Biserka

    2013-10-01

    In the present study, the importance of considering fish intestinal parasites i.e. the acanthocephalans in metal exposure assessment was estimated under low metal contamination conditions. Two acanthocephalan species, Pomphorhynchus laevis and Acanthocephalus anguillae were examined in 59 specimens of European chub (Squalius cephalus L.) sampled at 5 locations along the Sava River, Croatia. Concentrations of essential (Cu, Mn) and non-essential (Ag, Cd, Pb) metals were higher in intestinal parasites than chub gastrointestinal tissue, but levels of essential metals Fe and Zn were comparable or lower in parasites, respectively. The highest accumulation in both acanthocephalan species was found for non-essential metals and followed the order: Ag>Pb>Cd. Higher infection intensity with P. laevis allowed us to present their spatial metal distribution and evaluate the influence of P. laevis on metal levels and sub-cellular biological responses (total protein and metallothionein levels) in the host infected with P. laevis. Even in the river section with low metal contamination, parasitism affected metal levels, resulting in lower Cu, Cd and Pb concentrations in chub infected with P. laevis than in uninfected chub. Although total protein and metallothionein levels remained constant in infected and uninfected chub, acanthocephalans should be considered a potential confounding factor in metal exposure assessments. Moreover, P. laevis-chub system can be suggested as an appropriate tool in biomonitoring, since in both species increased Cu and Cd concentrations towards the downstream locations were found. Higher Cu and Cd levels in P. laevis suggest acanthocephalans to be sensitive bioindicators if low metal levels have to be detected. PMID:23856403

  12. Feasibility of a nickel-metal hydride battery for totally implantable artificial hearts.

    PubMed

    Okamoto, E; Yoshida, T; Fujiyoshi, M; Shimanaka, M; Takeuchi, A; Mitamura, Y; Mikami, T

    1996-01-01

    An implantable rechargeable battery is one of the key technologies for totally implantable artificial hearts. The nickel-metal hydride (Ni-MH) battery is promising for its high energy density of 1.5-2.0 times that of a nickel-cadmium battery. In this study, the effects of pulsatile discharge loads on the operating time and cycle life of Ni-MH batteries at 39 degrees C were studied. Two battery cells (TH-3M, 1,200 mAh, phi 14.5 x 49 mm; Toshiba, Tokyo, Japan) in series were charge/discharge cycled at 39 degrees C using a charge current of 1CA (1,200 mA) and then were fully discharged to 1.0 V/cell under either pulsatile discharge loads, which mimicked a systole (1 A for 0.3 sec) and a diastole (0.4 A for 0.3 sec), or a non pulsatile discharge load equivalent to the average of the pulsatile loads (0.7 A). Each cycle life test was interrupted on the 482nd cycle under pulsatile load, and on the 423rd cycle under non pulsatile load, because of malfunction of each battery charger. The tests showed that the pulsatile discharge cells had significantly (p < 0.001) less operating time (74.0 +/- 7.15 min) throughout the test period (up to 482 days) compared to the cells under equivalent non pulsatile discharge loads (93.7 +/- 7.74 min). The pulsatile-discharged Ni-MH cells provide significantly less operating time than the constantly discharged cells; the Ni-MH battery has an operating time of over 78 min and a cycle life of almost 500 cycles at 39 degrees C. In conclusion, the Ni-MH battery is feasible as an implantable back-up battery for a totally implantable artificial heart system. PMID:8944901

  13. Contact mechanics of modular metal-on-polyethylene total hip replacement under adverse edge loading conditions.

    PubMed

    Hua, Xijin; Li, Junyan; Wang, Ling; Jin, Zhongmin; Wilcox, Ruth; Fisher, John

    2014-10-17

    Edge loading can negatively impact the biomechanics and long-term performance of hip replacements. Although edge loading has been widely investigated for hard-on-hard articulations, limited work has been conducted for hard-on-soft combinations. The aim of the present study was to investigate edge loading and its effect on the contact mechanics of a modular metal-on-polyethylene (MoP) total hip replacement (THR). A three-dimensional finite element model was developed based on a modular MoP bearing. Different cup inclination angles and head lateral microseparation were modelled and their effect on the contact mechanics of the modular MoP hip replacement were examined. The results showed that lateral microseparation caused loading of the head on the rim of the cup, which produced substantial increases in the maximum von Mises stress in the polyethylene liner and the maximum contact pressure on both the articulating surface and backside surface of the liner. Plastic deformation of the liner was observed under both standard conditions and microseparation conditions, however, the maximum equivalent plastic strain in the liner under microseparation conditions of 2000 µm was predicted to be approximately six times that under standard conditions. The study has indicated that correct positioning the components to avoid edge loading is likely to be important clinically even for hard-on-soft bearings for THR. PMID:25218504

  14. Midterm Follow-Up of Metal-Backed Glenoid Components in Anatomical Total Shoulder Arthroplasties.

    PubMed

    Obermeyer, Thomas; Cagle, Paul J; Parsons, Bradford O; Flatow, Evan L

    2015-09-01

    Loosening of the glenoid remains one of the most common complications of total shoulder arthroplasty (TSA) and is the most cited reason for performing revision arthroplasty. Ingrowth metal-backed glenoid components offer the theoretical advantage of bone growth directly into the prosthesis with a single host-prosthesis interface. In the study reported here, we retrospectively reviewed the charts of patients who had TSAs performed by 2 fellowship-trained shoulder surgeons using glenoid components with porous tantalum anchors. Standard radiographs were analyzed for lucency surrounding the anchors. Before and after surgery, American Shoulder and Elbow Surgeons (ASES) scores and active forward elevation (AFE) and active external rotation (AER) measurements were recorded. Twelve shoulders (11 patients) were examined. Mean follow-up was 20 months. In all cases, radiographs showed no glenoid lucency. Mean AFE and mean AER both increased significantly (P < .01), as did postoperative ASES scores (P < .01). Porous tantalum ingrowth glenoid components show no radiographic or clinical evidence of loosening at midterm follow-up. Long-term studies are needed to determine if these midterm outcomes are maintained and provide benefit over conventional cemented polyethylene designs. PMID:26372761

  15. Metal-backed versus all-polyethylene tibial components in primary total knee arthroplasty

    PubMed Central

    2011-01-01

    Background and purpose The choice of either all-polyethylene (AP) tibial components or metal-backed (MB) tibial components in total knee arthroplasty (TKA) remains controversial. We therefore performed a meta-analysis and systematic review of randomized controlled trials that have evaluated MB and AP tibial components in primary TKA. Methods The search strategy included a computerized literature search (Medline, EMBASE, Scopus, and the Cochrane Central Register of Controlled Trials) and a manual search of major orthopedic journals. A meta-analysis and systematic review of randomized or quasi-randomized trials that compared the performance of tibial components in primary TKA was performed using a fixed or random effects model. We assessed the methodological quality of studies using Detsky quality scale. Results 9 randomized controlled trials (RCTs) published between 2000 and 2009 met the inclusion quality standards for the systematic review. The mean standardized Detsky score was 14 (SD 3). We found that the frequency of radiolucent lines in the MB group was significantly higher than that in the AP group. There were no statistically significant differences between the MB and AP tibial components regarding component positioning, knee score, knee range of motion, quality of life, and postoperative complications. Interpretation Based on evidence obtained from this study, the AP tibial component was comparable with or better than the MB tibial component in TKA. However, high-quality RCTs are required to validate the results. PMID:21895503

  16. Contact mechanics of modular metal-on-polyethylene total hip replacement under adverse edge loading conditions

    PubMed Central

    Hua, Xijin; Li, Junyan; Wang, Ling; Jin, Zhongmin; Wilcox, Ruth; Fisher, John

    2014-01-01

    Edge loading can negatively impact the biomechanics and long-term performance of hip replacements. Although edge loading has been widely investigated for hard-on-hard articulations, limited work has been conducted for hard-on-soft combinations. The aim of the present study was to investigate edge loading and its effect on the contact mechanics of a modular metal-on-polyethylene (MoP) total hip replacement (THR). A three-dimensional finite element model was developed based on a modular MoP bearing. Different cup inclination angles and head lateral microseparation were modelled and their effect on the contact mechanics of the modular MoP hip replacement were examined. The results showed that lateral microseparation caused loading of the head on the rim of the cup, which produced substantial increases in the maximum von Mises stress in the polyethylene liner and the maximum contact pressure on both the articulating surface and backside surface of the liner. Plastic deformation of the liner was observed under both standard conditions and microseparation conditions, however, the maximum equivalent plastic strain in the liner under microseparation conditions of 2000 µm was predicted to be approximately six times that under standard conditions. The study has indicated that correct positioning the components to avoid edge loading is likely to be important clinically even for hard-on-soft bearings for THR. PMID:25218504

  17. Prospective analysis of the incidence of metal allergy in patients listed for total replacement of the temporomandibular joint.

    PubMed

    Sidebottom, A J; Mistry, K

    2014-01-01

    We prospectively analysed the incidence of metal allergies in patients listed for total replacement of the temporomandibular joint (TMJ) and the efficacy of patch testing to prevent rejection phenomena. All patients (n=101) that required a prosthetic TMJ between March 2004 and August 2012 were tested preoperatively. A total of 39% had an allergy to one or more metals and they were given all-titanium prostheses. Following the introduction of this protocol no patients have shown signs of an allergic rejection within 6 months of operation. We suggest that all patients listed for total TMJ replacement should have patch tests for metal allergies and that all-titanium prostheses are used when allergy is detected. PMID:23850381

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

    PubMed Central

    Mihalko, William M.; Grupp, Thomas M.; Manning, Blaine T.; Dennis, Douglas A.; Goodman, Stuart B.; Saleh, Khaled J.

    2015-01-01

    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. PMID:25883940

  19. Biomaterial hypersensitivity: is it real? Supportive evidence and approach considerations for metal allergic patients following total knee arthroplasty.

    PubMed

    Mitchelson, Andrew J; Wilson, Craig J; Mihalko, William M; Grupp, Thomas M; Manning, Blaine T; Dennis, Douglas A; Goodman, Stuart B; Tzeng, Tony H; Vasdev, Sonia; Saleh, Khaled J

    2015-01-01

    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. PMID:25883940

  20. Analysis of trace metals in thin silicon nitride films by total-reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Vereecke, G.; Arnauts, S.; Van Doorne, P.; Kenis, K.; Onsia, B.; Verstraeten, K.; Schaekers, M.; Van Hoeymissen, J. A. B.; Heyns, M. M.

    2001-11-01

    The validity of a matrix withdrawal method for the analysis of trace metals in silicon nitride films on silicon wafers by total-reflection X-ray fluorescence has been evaluated with samples contaminated with diluted standard solutions of eight metals (Ca, V, Cr, Fe, Ni, Cu, Ta, W). The nitride matrix was removed by a decomposition step with HF vapor at ambient conditions followed by the vaporization of the product at a temperature higher than 240°C. The recovery of added metals was determined first directly after vaporization and secondly after preconcentration by the droplet collection (DC) method. The recovery of metals after vaporization at a temperature of 300±50°C was generally close to 100%, except for Cu whose recovery was approximately 40%. The efficiency of the DC step was approximately 50% for most metals but only 10-20% for Cu and Cr. Thus for most metals the total recovery was close to 50%, which is acceptable for analytical purpose. The recovery of Cu and Cr was studied in more detail considering the influence of the thickness of the nitride film, the vaporization temperature, and the composition of the DC solution. The total recovery of Cu increased from approximately 10 to 40% by lowering the temperature of the vaporization step and using a more concentrated DC solution. The recovery of Cr by DC was markedly influenced by the thickness of the nitride film with no great benefit of using a more concentrated DC solution.

  1. 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.

    PubMed

    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. PMID:24952252

  2. Modeling of Total Ionizing Dose Effects in Advanced Complementary Metal-Oxide-Semiconductor Technologies

    NASA Astrophysics Data System (ADS)

    Sanchez Esqueda, Ivan

    2011-12-01

    The increased use of commercial complementary metal-oxide-semiconductor (CMOS) technologies in harsh radiation environments has resulted in a new approach to radiation effects mitigation. This approach utilizes simulation to support the design of integrated circuits (ICs) to meet targeted tolerance specifications. Modeling the deleterious impact of ionizing radiation on ICs fabricated in advanced CMOS technologies requires understanding and analyzing the basic mechanisms that result in buildup of radiation-induced defects in specific sensitive regions. Extensive experimental studies have demonstrated that the sensitive regions are shallow trench isolation (STI) oxides. Nevertheless, very little work has been done to model the physical mechanisms that result in the buildup of radiation-induced defects and the radiation response of devices fabricated in these technologies. A comprehensive study of the physical mechanisms contributing to the buildup of radiation-induced oxide trapped charges and the generation of interface traps in advanced CMOS devices is presented in this dissertation. The basic mechanisms contributing to the buildup of radiation-induced defects are explored using a physical model that utilizes kinetic equations that captures total ionizing dose (TID) and dose rate effects in silicon dioxide (SiO2). These mechanisms are formulated into analytical models that calculate oxide trapped charge density (Not) and interface trap density (Nit) in sensitive regions of deep-submicron devices. Experiments performed on field-oxide-field-effect-transistors (FOXFETs) and metal-oxide-semiconductor (MOS) capacitors permit investigating TID effects and provide a comparison for the radiation response of advanced CMOS devices. When used in conjunction with closed-form expressions for surface potential, the analytical models enable an accurate description of radiation-induced degradation of transistor electrical characteristics. In this dissertation, the incorporation

  3. Determination of heavy metals in macrozoobenthos from the rivers Tisza and Szamos by total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Woelfl, S.; Mages, M.; Óvári, M.; Geller, W.

    2006-11-01

    In 2000, accidents in the Romanian mining industry in key catchment areas led to heavy metal contamination of the Hungarian rivers Tisza and Szamos resulting in substantial heavy metal loads in several sediments of the upper river basins. This enhanced metal content might have been bioaccumulated in benthic organisms during the following years. Therefore, the aim of this study was to test, whether the zoobenthic fauna showed an enhanced metal content 3 years after the industrial accident. Macrozoobenthic insect larvae (chironomids) were sampled 100 m below and above the confluent site of the rivers Tisza and Szamos during summer 2003 and for comparison purpose also in the river Maros, a tributary of the Tisza river, during 2005. In order to determine their heavy metal content, single specimens were prepared and analysed by Total Reflection X-ray Fluorescence Spectrometry (TRXF) according to the modified dry method. Fe was much lower and Mn and Zn much higher concentrated in benthos from the more contaminated Szamos river compared to the Tisza and Maros rivers. In this sense, the benthic organisms reflected very well the enhanced metal concentrations in the contaminated rivers being suitable as bioindicators of metal contamination. However, the sediment bioaccumulation factor was low at all sampling sites indicating a low bioavailability of trace metals for benthic organisms.

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

    SciTech Connect

    Jing, Chengbin; Guo, Hong; Hu, Zhigao; Yang, Pingxiong; Chu, Junhao; Liu, Aiyun; Shi, Yiwei

    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).

  5. Total fume and metal concentrations during welding in selected factories in Jeddah, Saudi Arabia.

    PubMed

    Balkhyour, Mansour Ahmed; Goknil, Mohammad Khalid

    2010-07-01

    Welding is a major industrial process used for joining metals. Occupational exposure to welding fumes is a serious occupational health problem all over the world. The degree of risk to welder's health from fumes depends on composition, concentration, and the length of exposure. The aim of this study was to investigate workers' welding fume exposure levels in some industries in Jeddah, Saudi Arabia. In each factory, the air in the breathing zone within 0.5 m from welders was sampled during 8-hour shifts. Total particulates, manganese, copper, and molybdenum concentrations of welding fumes were determined. Mean values of eight-hour average particulate concentrations measured during welding at the welders breathing zone were 6.3 mg/m(3) (Factory 1), 5.3 mg/m(3) (Factory 2), 11.3 mg/m(3) (Factory 3), 6.8 mg/m(3) (Factory 4), 4.7 mg/m(3) (Factory 5), and 3.0 mg/m(3) (Factory 6). Mean values of airborne manganese, copper, and molybdenum levels measured during welding were in the range of 0.010 mg/m(3)-0.477 mg/m(3), 0.001 mg/m(3)-0.080 mg/m(3) and 0.001 mg/m(3)-0.058 mg/m(3) respectively. Mean values of calculated equivalent exposure values were: 1.50 (Factory 1), 1.56 (Factory 2), 5.14 (Factory 3), 2.21 (Factory 4), 2.89 (Factory 5), and 1.20 (Factory 6). The welders in factories 1, 2, 3, and 4 were exposed to welding fume concentration above the SASO limit value, which may increase the risk of respiratory health problems. PMID:20717553

  6. Determination of the toxicity characteristic for metals in soil: A comparison of the toxicity characteristic leaching procedure and total metal determination

    SciTech Connect

    Bass, D.A.; Taylor, J.D.

    1994-12-01

    A comparison is made of the concentrations of metals extracted from soils using the Toxicity Characteristic Leaching Procedure (TCLP) and a total determination method. This information is of interest in two ways. First, it is hoped that a relationship might be established between the amount of each metal determined after extraction by the TCLP and the amount determined using a total determination method. And second, data are also presented which indicate the general extractability of various metals in soil samples using the TCLP. This study looks specifically at inorganic elements (Sb, As, Ba, Cd, Cu, Cr, Pb, Mg, Hg, Se, Ag, Sn, and Zn) in soils from a firing range. Results show that total determination methods for metals can not generally be used for heterogeneous samples, such as soil samples from a firing range. Some correlation between a total determination method and TCLP was observed when Ba and Cd were present in the samples at lower concentrations (less than 80 mg/kg for Ba and less than 25 mg/kg for Cd); however, additional data are necessary to verify this correlation.

  7. Attosecond Electro-Magnetic Forces Acting on Metal Nanospheres Induced By Relativistic Electrons

    NASA Astrophysics Data System (ADS)

    Lagos, M. J.; Batson, P. E.; Reyes-Coronado, A.; Echenique, P. M.; Aizpurua, J.

    2014-03-01

    Swift electron scattering near nanoscale materials provides information about light-matter behavior, including induced forces. We calculate time-dependent electromagnetic forces acting on 1-1.5 nm metal nanospheres induced by passing swift electrons, finding both impulse-like and oscillatory response forces. Initially, impulse-like forces are generated by a competition between attractive electric forces and repulsive magnetic forces, lasting a few attoseconds (5-10 as). Oscillatory, plasmonic response forces take place later in time, last a few femtoseconds (1- 5 fs), and apparently rely on photon emission by decay of the electron-induced surface plasmons. A comparison of the strength of these two forces suggests that the impulse-like behavior dominates the process, and can transfer significant linear momentum to the sphere. Our results advance understanding of the physics behind the observation of both attractive and repulsive behavior of gold nano-particles induced by electron beams in aberration-corrected electron microscopy. Work supported under DOE, Award # DE-SC0005132, Basque Gov. project ETORTEK inano, Spanish Ministerio de Ciencia e Innovacion, No. FIS2010-19609-C02-01.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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. PMID:23315152

  10. Evaluation of the wear properties of a metal-on-metal total joint replacement system and in vitro macrophage response to resultant wear particles

    NASA Astrophysics Data System (ADS)

    St. John, Kenneth Raymond

    The wear of the polyethylene in total joint prostheses has been a source of morbidity and early device failure which has been extensively reported in the last ten to twelve years. While research continues to attempt to reduce the wear of polyethylene joint bearing surfaces by modifications in polymer processing, there is a renewed interest in the use of metal-on-metal bearing couples for hip replacement devices. This study investigated the in vitro wear resistance of two cobalt/chromium/molybdenum alloys, which differed primarily in the carbon content, as potential alloys for use in such a metal-on-metal hip bearing couple. The results showed that the alloy with the higher (0.25%) carbon content was more wear resistant and this alloy was chosen for testing in a hip simulator system which modeled the loads and motions which might be exerted on a clinically implanted hip replacement. Comparison of the results of metal-on-polyethylene specimens to metal-on-metal specimens showed that the volumetric wear of the metal-on-polyethylene bearing couple over 5,000,000 cycles was 110--180 times as great as that for the metal bearing couple. Polyethylene and metal particles retrieved from either pin-on-disk testing lubricant or hip simulator testing lubricant were cleaned and examined for consistency with the particles reported by other laboratories for particles from periprosthetic tissues and found to be similar. The particles were then added to macrophage (J774a) cell cultures and the release of Prostaglandin E2, Interleukin-6, and Tumor Necrosis Factor alpha measured for each experiment in response to the particles. The cell mediators released by the cells was found to correlate with the dosage of particles and the chemical identity of the particles. Most of the cellular response to the polyethylene particles seemed to be as a result of phagocytosis of the particles while most of the response to metal particles seemed to be related to cytotoxicity of the particles. Based

  11. Spatio-temporal variability of solid, total dissolved and labile metal: passive vs. discrete sampling evaluation in river metal monitoring.

    PubMed

    Priadi, Cindy; Bourgeault, Adeline; Ayrault, Sophie; Gourlay-Francé, Catherine; Tusseau-Vuillemin, Marie-Hélène; Bonté, Philippe; Mouchel, Jean-Marie

    2011-05-01

    In order to obtain representative dissolved and solid samples from the aquatic environment, a spectrum of sampling methods are available, each one with different advantages and drawbacks. This article evaluates the use of discrete sampling and time-integrated sampling in illustrating medium-term spatial and temporal variation. Discrete concentration index (CI) calculated as the ratio between dissolved and solid metal concentrations in grab samples are compared with time-integrated concentration index (CI) calculated from suspended particulate matter (SPM) collected in sediment traps and labile metals measured by the diffusive gel in thin films (DGT) method, collected once a month during one year at the Seine River, upstream and downstream of the Greater Paris Region. Discrete CI at Bougival was found to be significantly higher than at Triel for Co, Cu, Mn, Ni and Zn, while discrete metal partitioning at Marnay was found to be similar to Bougival and Triel. However, when using time-integrated CI, not only was Bougival CI significantly higher than Triel CI, CI at Marnay was also found to be significantly higher than CI at Triel which was not observed for discrete CI values. Since values are time-averaged, dramatic fluctuations were smoothed out and significant medium-term trends were enhanced. As a result, time-integrated concentration index (CI) was able to better illustrate urbanization impact between sites when compared to discrete CI. The impact of significant seasonal phenomenon such as winter flood, low flow and redox cycles was also, to a certain extent, visible in time-integrated CI values at the upstream site. The use of time-integrated concentration index may be useful for medium- to long-term metal studies in the aquatic environment. PMID:21468423

  12. Surface and Subsurface Analyses of Metal-on-Polyethylene Total Hip Replacement Retrievals.

    PubMed

    Vuong, Vicky; Pettersson, Maria; Persson, Cecilia; Larsson, Sune; Grandfield, Kathryn; Engqvist, Håkan

    2016-05-01

    Metal-on-polyethylene (MoP) articulations are one of the most reliable implanted hip prostheses. Unfortunately, long-term failure remains an obstacle to the service life. There is a lack of higher resolution research investigating the metallic surface component of MoP hip implants. This study investigates the surface and subsurface features of metallic cobalt chromium molybdenum alloy (CoCrMo) femoral head components from failed MoP retrievals. Unused prostheses were used for comparison to differentiate between wear-induced defects and imperfections incurred during implant manufacturing. The predominant scratch morphology observed on the non-implanted references was shallow and linear, whereas the scratches on the retrievals consisted of largely nonlinear, irregular scratches of varying depth (up to 150 nm in retrievals and up to 60 nm in reference samples). Characteristic hard phases were observed on the surface and subsurface material of the cast samples. Across all samples, a 100-400 nm thick nanocrystalline layer was visible in the immediate subsurface microstructure. Although observation of the nanocrystalline layer has been reported in metal-on-metal articulations, its presence in MoP retrievals and unimplanted prostheses has not been extensively examined. The results suggest that manufacturing-induced surface and subsurface microstructural features are present in MoP hip prostheses prior to implantation and naturally, these imperfections may influence the in vivo wear processes after implantation. PMID:26399989

  13. 75 FR 43160 - Clean Water Act Section 303(d): Final Agency Action on One Arkansas Total Maximum Daily Load (TMDL)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-23

    .../region6/water/npdes/tmdl/index.htm . FOR FURTHER INFORMATION CONTACT: Diane Smith at (214) 665-2145. EPA... Final TMDL may be found at http://www.epa.gov/region6/water/npdes/tmdl/index.htm . Dated: July 15, 2010. Claudia V. Hosch, Acting Director, Water Quality Protection Division, EPA Region 6. BILLING CODE 6560-50-P...

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

    PubMed

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

    2006-11-01

    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. PMID:16530310

  15. The influence of metallic shell deformation on the contact mechanics of a ceramic-on-ceramic total hip arthroplasty.

    PubMed

    Qiu, Changdong; Wang, Ling; Li, Dichen; Jin, Zhongmin

    2016-01-01

    Total hip arthroplasty of ceramic-on-ceramic bearing combinations is increasingly used clinically. The majority of these implants are used with cementless fixation that a metal-backing shell is press-fitted into the pelvic bone. This usually results in the deformation of the metallic shell, which may also influence the ceramic liner deformation and consequently the contact mechanics between the liner and the femoral head under loading. The explicit dynamic finite element method was applied to model the implantation of a cementless ceramic-on-ceramic with a titanium shell and subsequently to investigate the effect of the metallic shell deformation on the contact mechanics. A total of three impacts were found to be necessary to seat the titanium alloy shell into the pelvic bone cavity with a 1 mm diameter interference and a 1.3 kg impactor at 4500 mm s(-1) velocity. The maximum deformation of the metallic shell was found to be 160 µm in the antero-superior and postero-inferior direction and 97 µm in the antero-inferior and postero-superior direction after the press-fit. The corresponding values were slightly reduced to 67 and 45 µm after the ceramic liner was inserted and then modified to 74 and 43 µm under loading, respectively. The maximum deformation and the maximum principal stress of the ceramic liner were 31 µm and 144 MPa (tensile stress), respectively, after it was inserted into the shell and further increased to 52 µm and 245 MPa under loading. This research highlights the importance of the press-fit of the metallic shell on the contact mechanics of the ceramic liner for ceramic-on-ceramic total hip arthroplasties and potential clinical performances. PMID:26511269

  16. Combined effect of smoking habits and occupational exposure to hard metal on total IgE antibodies

    SciTech Connect

    Shirakawa, T.; Kusaka, Y.; Morimoto, K. )

    1992-06-01

    A survey was made within a population of workers (n = 706) exposed to hard metal dust (an alloy including cobalt), an agent known to cause occupational allergy. Twenty-seven (4 percent) of 733 workers were eliminated from consideration in this study because of atopic status identified prior to starting work in the plant. Using a Phadebas PRIST, the subjects' total IgE levels were determined and related to their smoking and exposure status. Nonexposed male smokers (n = 135) had a higher geometric mean IgE level (39.7 IU/ml) than did nonexposed subjects who had never smoked (33.1 IU/ml; n = 99); those with a higher Brinkman index (greater than 300), a smoking index obtained by multiplying the number of cigarettes per day by the duration of smoking in years, had significantly (p less than 0.05) decreased IgE levels. Although ex-smokers (n = 72) had a higher geometric mean IgE level (73.3 IU/ml) than did those who had never smoked, their serum IgE level declined with age since the time they quit smoking, regardless of their hard metal exposure status. Hard metal (cobalt) exposure may play a significant role as an adjuvant in the production of total IgE. A multivariate analysis demonstrated that hard metal exposure and a smoking habit together arithmetically (p less than 0.05) increased total IgE levels. These two factors may be preventable risk factors for occupational allergy in hard metal workers.

  17. The Characterization of Total and Leachable Metals in Foundry Molding Sands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Waste molding sands from the foundry industry have been successfully used as a component in manufactured soils, but concern over metal contamination must be addressed before many states will consider this beneficial use. Since there is little data available on this topic, the purpose of this study ...

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

    PubMed

    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 <0.001 to 2.9mg/m(3), and, in all but one case, resulted in concentrations below the current U.S. Occupational Safety and Health Administration's Permissible Exposure Limits and the American Conference of Governmental Industrial Hygienists' Threshold Limit Values. The arithmetic mean total dust concentration resulting from long-term personal samples was 0.31mg/m(3). The data presented here are the most complete set of its kind in the open literature, and are useful for understanding the potential exposures during solid catalyst handling activities at this petroleum refinery and perhaps other modern refineries during the timeframe examined. PMID:22177528

  19. Cancer incidence and causes of death among total hip replacement patients: a review based on Nordic cohorts with a special emphasis on metal-on-metal bearings.

    PubMed

    Visuri, T I; Pukkala, E; Pulkkinen, P; Paavolainen, P

    2006-02-01

    All patients with total hip arthroplasty (THA) are exposed to soluble or particulate forms of Co and Cr. Adverse effects of these wear products are not known. Data from Nordic registries is used to estimate adverse effects on a large scale, based mostly on metal-on-polyethylene bearings. Cancer incidence was in line with the general population when the patients were operated on for all indications and significantly decreased when the indication was primary osteoarthritis. Stomach cancer and colorectal cancers were significantly reduced and prostate cancer and skin melanoma significantly increased. There was no significant excess of cancer in target organs, i.e. liver, kidney, or haematopoietic cancers. THA patients had reduced mortality and extended life expectancy compared with standard Nordic populations. All-site cancer incidence of the first-generation metal-on-metal McKee-Farrar patients operated on for primary osteoarthritis was in line with the general population after follow-up for up to 28 years. General mortality of these patients was also reduced and they also had an extended life expectancy. Temporary increases in haematopoietic cancers at different follow-up periods were seen in some cohorts. This malignancy deserves a special record linkage monitoring while large numbers of young patients are provided with the second generation of metal-on-metal prostheses. PMID:16669405

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

    NASA Astrophysics Data System (ADS)

    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.

  1. [Effect analysis on the two total load control methods for poisonous heavy metals].

    PubMed

    Fu, Guo-Wei

    2012-12-01

    Firstly it should be made clear that implementation of source total load control for the first type of pollutants is necessary for environmental pollution control legislation and economic structure regulation. This kind of surveillance method has been more practical to be implemented since the Manual of the Industry Discharge Coefficient of First National Pollution Sources Investigation was published. The source total load control and water environment total load control are independent of each other and none of them is redundant, on the other side they can be complementary to each other. In the present, some local planning managers are blurring and confusing the contents and styles of the two surveillance methods. They just use the water total load control to manage all the pollutants, and source total load control is discarded, which results in the loss of control for the first type of pollutants especially for the drinking water source surveillance. There is a big difference between the water quality standards and the water environmental background concentration values for the first type of pollutants in the Environmental quality standard for surface water (GB 3838-88), which means that there are problems such as "relaxing the pollutant discharge permit" and "risk induced by valence state change". Taking an enterprise with 10t electrolytic lead production capacity as an example, there is a big difference between the allowable lead discharged loads by the two total load surveillance methods. In summary, it will bring a lot of harmful effects if the water total load control is implemented for the two types of pollutants, so the source total load control and water environmental total load control should be implemented strictly at the same time. PMID:23379176

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

    NASA Astrophysics Data System (ADS)

    Marguí, Eva; Queralt, Ignasi; Hidalgo, Manuela

    2013-08-01

    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.

  3. [Evaluation of per- and postoperative bleeding in 250 poro-metal total hip prostheses without cement].

    PubMed

    Charhon, F; Dubost, T; Terville, J P; Pastéyer, J; Roulier, J P

    1977-01-01

    Arthroplasty of the hip without cement in poro-metal (JUDET type) represents real progress. However, per-operative bleeding is greater, 48 per cent of patients losing more than 2000 ml and 25 per cent more than 3000 ml. Various factors may influence the degree of haemorrhage: the operative indication, the time of the operation and the administration of Calcium heparinate are studied. Postoperatively, overall blood loss then in relation to per-operative bleeding were evaluated. PMID:23020

  4. Increased Mortality in Metal-on-Metal versus Non-Metal-on-Metal Primary Total Hip Arthroplasty at 10 Years and Longer Follow-Up: A Systematic Review and Meta-Analysis

    PubMed Central

    Meessen, J. M. T. A.; Fiocco, M.; van der Heide, H. J. L.; Sedrakyan, A.; Nelissen, R. G. H. H.

    2016-01-01

    Importance There are concerns about increased mortality in patients with metal-on-metal bearings in total hip arthroplasty (THA). Objective To determine the mortality and the morbidity in patients with metal-on-metal articulations (MOM THA) compared to patients with non-metal-on-metal articulations (non-MOM THA) after primary total hip arthroplasty. Data Sources Search of PubMed, MEDLINE, EMBASE, Web of Science, Cochrane, CINAHL, AcademicSearchPremier, ScienceDirect, Wiley and clinical trial registers through March 2015, augmented by a hand search of references from the included articles. No language restrictions were applied. Study Selection Two reviewers screened and identified randomised controlled trials and observational studies of primary total hip arthroplasty comparing MOM THA with non-MOM THA. Data Extraction and Synthesis Two reviewers independently extracted study data and assessed risk of bias. Risk differences (RD) were calculated with random effect models. Meta-regression was used to explore modifying factors. Main Outcomes and Measures Difference in mortality and difference in morbidity expressed as revisions and medical complications between patients with MOM THA and non-MOM THA. Results Forty-seven studies were included, comprising 4,000 THA in randomised trials and over 500,000 THA in observational studies. For mortality, random effects analysis revealed a higher pooled RD of 0.7%, 95%, confidence interval (CI) [0.0%, 2.3%], I-square 42%; the heterogeneity was explained by differences in follow-up. When restricted to studies with long term follow-up (i.e. 10 years or more), the RD for mortality was 8.5%, 95%, CI [5.8%, 11.2%]; number needed to treat was 12. Further subgroup analyses and meta-regression random effects models revealed no evidence for other moderator variables (study level covariates, e.g. resurfacing vs. non-resurfacing MOM) than follow-up duration. The quality of the evidence presented in this meta-analysis was characterized as

  5. Incomplete seating of a metal-backed alumina liner in ceramic-on-ceramic total hip arthroplasty.

    PubMed

    Carvajal Alba, Jaime A; Schiffman, Eric D; Scully, Sean P; Parvataneni, Hari K

    2010-01-01

    Metal-backed modular ceramic bearing systems using a recessed alumina liner in a titanium sleeve were developed to decrease ceramic chipping or fracture due to femoral neck impingement after total hip arthroplasty (THA). However, malseating of the metal-backed ceramic liner has recently been described. The goal of this study was to assess the prevalence, etiology, and clinical relevance of this event. Between 2005 and 2008, 51 consecutive patients (61 hips) underwent THA with a metal-backed alumina liner housed in a titanium shell. The metal-backed ceramic liner was aligned, seated, and impacted into the shell, and satisfaction in terms of liner stability and seating was confirmed intraoperatively. Postoperative assessment of seating was assessed with standard radiographs. Liner seating was classified as well seated, suspicious, or malseated. Seven liners (11.5%) were found to be malseated and 4 (6.5%) were considered suspicious. Radiographically, there was a gap between the liner and the shell located inferomedially in 4 patients and superolaterally in 3 patients. Two liners subsequently seated at 1 and 3 months postoperatively, respectively. No dislodgement, failures, or adverse events were identified. There were no revision surgeries. The significant percentage of malseated liners were potentially attributed to poor exposure, bony/soft tissue interposition, and surgeon learning curve. PMID:20055343

  6. Zirconia phase transformation, metal transfer, and surface roughness in retrieved ceramic composite femoral heads in total hip arthroplasty.

    PubMed

    Elpers, Marcella; Nam, Denis; Boydston-White, Susie; Ast, Michael P; Wright, Timothy M; Padgett, Douglas E

    2014-11-01

    Ceramic femoral heads have had promising results as a bearing surface in total hip arthroplasty. Our objective was to evaluate a series of retrieved alumina-zirconia composite ceramic femoral heads for evidence of the tetragonal to monoclinic zirconia phase transformation, metal transfer and articular surface roughness. Raman spectra showed evidence of the zirconia phase transformation in all retrieved specimens, with distinct monoclinic peaks at 183, 335, 383, and 479 cm(-1). All components displayed metal transfer. An increase in the zirconia phase transformation was seen with increasing time in vivo. No correlation between extent of zirconia phase transformation and the surface roughness was found. These short-term results suggest that the use of an alumina-zirconia composite ceramic is a viable option for femoral heads in THA. PMID:25212282

  7. Mercury Induced by Pressure to act as a Transition Metal in Mercury Fluorides

    NASA Astrophysics Data System (ADS)

    Botana, Jorge; Wang, Xiaoli; Hou, Chunju; Yan, Dadong; Lin, Haiqing; Ma, Yanming; Miao, Mao-Sheng

    The question of whether Hg is a transition metal remains open for stable solids. In our work we propose that high-pressure techniques will help prepare unusual oxidation states of Hg in Hg-F compounds. By means of ab initio calculations and an advanced structure-search algorithm we find that under high pressure charge is transferred from the Hg d orbitals to the F, and becomes a transition metal. HgF3 and HgF4 have been found to be stable compounds at high pressure. HgF4 consists of planar molecules, a typical geometry for d8 metallic centers. HgF3 is an example of metallic and ferromagnetic compound, with an electronic structure analogous to transparent conductors due to the Hg d9 configuration.

  8. Luminescent silver nanoclusters acting as a label-free photoswitch in metal ion sensing.

    PubMed

    Ghosh, Subhadip; Anand, Uttam; Mukherjee, Saptarshi

    2014-03-18

    In this work, we report the application of protein-templated Ag nanoclusters as a luminescent photoswitch for the detection of metal ions. Ag nanoclusters were synthesized using the circulatory protein human serum albumin (HSA) as a template, whose synthetic procedure can be tuned to make them toggle between blue-emitting (Ag9:HSA) and red-emitting (Ag14:HSA) nanoclusters. The photoluminescence (PL) intensity of Ag9:HSA was quenched significantly in the presence of 1 mM Co(II) ions. However, the PL of these quenched nanoclusters was completely restored in the presence of 3 mM Zn(II) ions. This enables them to be used as dual sensors and can serve as luminescent turn "on" and "off" metal switches. In contrast, the Ag14:HSA did not exhibit any photoswitchable properties but was able to detect Hg(II) selectively and to a high detection limit (10 nM). The luminescent-based sensing properties of these Ag:NCs were further supported by our time-resolved studies. The present study exhibits a promising step toward the application of luminescent metal nanoclusters as potential metal sensors since by tuning their luminescent properties we were able to detect and quantify metal ions selectively and simultaneously switch their sensing behaviors. PMID:24528116

  9. Wear simulation of a polyethylene-on-metal cervical total disc replacement under different concentrations of bovine serum lubricant.

    PubMed

    Hyde, P J; Fisher, J; Hall, R M

    2016-05-01

    Metal-on-polyethylene total disc replacements have been an alternative to spinal fusion in the lumbar spine under certain indications for more than a decade. Recently, cervical total disc replacement has also become an alternative to cervical fusion. Knowledge acquired from years of in vitro simulator studies on other joint replacements has highlighted the risks associated with premature wear due to unforeseen adverse clinical conditions and the effect of particulate debris on surrounding natural tissues. Having no evidence of the type and composition of the lubricating fluid that will result after spinal arthroplasty, a study on the effects of lubricant serum concentration was undertaken. The wear rate was shown to be inversely proportional to protein content of the serum over a range of 50%-3% bovine serum to water concentration. PMID:27160565

  10. A novel analytical approach for determining the frictional moments and torques acting on modular femoral components in total hip replacements.

    PubMed

    Farhoudi, H; Oskouei, R H; Jones, C F; Taylor, M

    2015-04-13

    A three dimensional analytical approach was developed to determine the frictional moment vector generated by the relative sliding of the head-cup bearing couple of a total hip replacement. The frictional moment projection onto the femoral neck was also determined over the loading cycle. Predicted frictional moments for nine combinations of bearing materials and diameters were in close agreement with existing in vitro data. The analytical method was then applied to simplified gait (lubrication conditions of dry and serum), ISO standard gait and physiological level gait loading cycles. ISO standard gait had a total contact force of about two fold of physiological level gait and there was a corresponding increase in the maximum frictional torque on neck from 0.66×BW%m to 0.88×BW%m. For the ISO standard gait, the maximum frictional torque occurred at the same instance of maximum frictional moment and the maximum contact force. In contrast, for the physiological level gait, the frictional torque did not occur at the same instance as the peak load. This suggests that the neck frictional torque is a function of other parameters, such as angle between neck axis and frictional moment vector, as well as the magnitude of the contact force and frictional moment. The developed methodology was able to predict the maximum magnitude and change of directions of moments and the variation of torque at the head neck interface. The data will be useful for experimental studies assessing the fretting behaviour of the head neck junction, by providing appropriate loading data. PMID:25721768

  11. Think regionally, act locally: metals in honeybee workers in the Netherlands (surveillance study 2008).

    PubMed

    van der Steen, J J M; Cornelissen, B; Blacquière, T; Pijnenburg, J E M L; Severijnen, M

    2016-08-01

    In June 2008, a surveillance study for metals in honeybees was performed in the Netherlands. Randomly, 150 apiaries were selected. In each apiary, five colonies were sampled. Per apiary, the hive samples were pooled. The apiary sample was analysed for Al, As, Ba, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Sb, Se, Sn, Sr, Ti, V and Zn. All metals could be detected in all apiaries. As, Li, Sb, Sn and V were detected in part of the apiaries. The overall picture showed a regional pattern. In apiaries in the east of the Netherlands, Al, Ba, Cr, Mn, Mo, Ni, Se and Ti are found in higher concentrations compared to the west. In-region variation was demonstrated, indicating local effects. The vicinity of the apiaries was mapped afterwards and characterised as land uses of >50 % agricultural area, >50 % wooded area, >50 % urban area and mixed land use within a circle of 28 km(2) around the apiary. The results indicated that in apiaries located in >50 % wooded areas, significantly higher concentrations of Al, Ba, Cd, Cr, Cu, Li, Mn, Mo, Ni, Sb, Sr, Ti and Zn were found compared to agricultural, urban and mixed land use areas. We conclude that (1) the ratio between metal concentrations varies per region, demonstrating spatial differences, and (2) there is in-region local variation per metal. The results indicate the impact of land use on metal concentrations in honeybees. For qualitative bioindication studies, regional, local and land use effects should be taken into account. PMID:27406208

  12. Trace metal determinations by total-reflection X-ray fluorescence analysis in the open Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Schmidt, Diether; Gerwinski, Wolfgang; Radke, Ina

    1993-02-01

    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. A first cruise with the RVMeteor to the eastern parts of the south and north Atlantic Ocean was successfully organized, in March and April 1990, from Cape Town (South Africa) to Funchal (Madeira, Portugal). Thirteen scientists from laboratories in Europe and North America participated with the first author as coordinator. 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. Additional methods applied, interalia, were anodic stripping voltammetry for lead and cadmium and graphite furnace atomic absorption spectrometry (GFAAS) for cadmium, using two different extraction procedures. 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 unaltered 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.

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

    NASA Astrophysics Data System (ADS)

    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 (< 0.7 μm). Similar trends were observed with most of the 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.

  14. Comparison of Whole-Blood Metal Ion Levels Among Four Types of Large-Head, Metal-on-Metal Total Hip Arthroplasty Implants: A Concise Follow-up, at Five Years, of a Previous Report.

    PubMed

    Hutt, Jonathan; Lavigne, Martin; Lungu, Eugen; Belzile, Etienne; Morin, François; Vendittoli, Pascal-André

    2016-02-17

    Few studies of total hip arthroplasty (THA) implants with a large-diameter femoral head and metal-on-metal design have directly compared the progression of metal ion levels over time and the relationship to complications. As we previously reported, 144 patients received one of four types of large-diameter-head, metal-on-metal THA designs (Durom, Birmingham, ASR XL, or Magnum implants). Cobalt, chromium, and titanium ion levels were measured over five years. We compared ion levels and clinical results over time. The Durom group showed the highest levels of cobalt (p ≤ 0.002) and titanium ions (p ≤ 0.03). Both the Durom and Birmingham groups demonstrated significant ongoing cobalt increases up to five years. Eight patients (seven with a Durom implant and one with a Birmingham implant) developed adverse local tissue reaction. Six Durom implants and one Birmingham implant required revision, with one pseudotumor under surveillance at the time of the most recent follow-up. We found that ion generation and related complications varied among designs. More concerning was that, for some designs, ion levels continued to increase. Coupling a cobalt-chromium adapter sleeve to an unmodified titanium femoral trunnion along with a large metal-on-metal bearing may explain the poor performances of two of the designs in the current study. PMID:26888673

  15. Impact of the Clean Water Act on the levels of toxic metals in urban estuaries: The Hudson River estuary revisited

    SciTech Connect

    Sanudo-Wilhelmy, S.A.; Gill, G.A.

    1999-10-15

    To establish the impact of the Clean Water Act on the water quality of urban estuaries, dissolved trace metals and phosphate concentrations were determined in surface waters collected along the Hudson River estuary between 1995 and 1997 and compared with samples collected in the mid-1970s by Klinkhammer and Bender. The median concentrations along the estuary have apparently declined 36--56% for Cu, 55--89% for Cd, 53--85% for Ni, and 53--90% for Zn over a period of 23 years. These reductions appear to reflect improvements in controlling discharges from municipal and industrial wastewater treatment plants since the Clean Water Act was enacted in 1972. In contrast, levels of dissolved nutrients (PO{sub 4}) have remained relatively constant during the same period of time, suggesting that wastewater treatment plant improvements in the New York/New Jersey Metropolitan area have not been as effective at reducing nutrient levels within the estuary. While more advanced wastewater treatment could potentially reduce the levels of Ag and PO{sub 4} along the estuary, these improvements would have a more limited effect on the levels of other trace metals.

  16. Total Hip Arthroplasty Using Metal Head on a Highly Cross-linked Polyethylene Liner

    PubMed Central

    Kim, Min-Yook; Park, Ji-Hoon; Lee, Jung-Ho

    2015-01-01

    Purpose This retrospective study was performed to evaluate the clinical results and measure polyethylene liner wear in total hip arthroplasty (THA) with highly cross-linked polyethylene. Materials and Methods Except for patients who had died or were unable to have follow-up at least 2 years, 60 of 78 hips that underwent THA were included this study. The mean age was 64.5 years (range, 25-81 years) and the mean body mass index (BMI) was 23.0 kg/m2 (18.1-32.3 kg/m2). Diagnosis at the time of the operation was osteonecrois of the femoral head in 28 hips, primary osteoarthritis in 14, hip fracture in 13, and other diseases in 5. The mean follow-up period was 3.8 years (2.1-7.1 years). Harris hip score (HHS) was reviewed before THA and at the last follow-up. On the anteroposterior pelvic radiographs, acetabular cup inclination and ante-version were also measured. The annual linear wear rate was measured using Livermore's method on the radiographs. Results The mean HHS was 60.1 (28-94) before operation and 90.4 (47-100) at the last follow-up. In the immediate post-operation, the average inclination and anteversion angles of the acetabular cups were 46.3° (standard deviation, ±6.7°) and, 21.4°(±10.1°) respectively. The mean of the annual linear polyethylene wear was 0.079 mm/year (0.001-0.291 mm/year). Age, gender and BMI were not statistically related to linear polyethylene wear but the period of follow-up and the acetabular cup's inclination showed significant negative and positive correlation respectively. Conclusion The wear rate of a highly cross-linked polyethylene was shown to correlate negatively with duration of follow-up. However, our study was based on a short-term follow-up, so a long-term follow-up study is necessary in the future. PMID:27536629

  17. Clinical outcome study and radiological findings of Zweymuller metal on metal total hip arthroplasty. a follow-up of 6 to 15 years.

    PubMed

    Paleochorlidis, Ilias S; Badras, Leonidas S; Skretas, Efstathios F; Georgaklis, Vasilios A; Karachalios, Theofilos S; Malizos, Konstantinos N

    2009-01-01

    We report the clinical and radiological outcome of 99 Zweymuller metal on metal total hip arthroplasties in 84 patients followed up prospectively for a mean period of 9.5 (range, 6-15) years. There were 29 (34.5%) male and 55 (65.5%) female patients with a mean age of 62.85 years (range, 50-70 years) at the time of surgery. All patients had osteoarthritis. One acetabular component and one stem were revised due to aseptic loosening. One femoral stem was revised due to a periprosthetic fracture. HHS score improved from a preoperative mean of 62.56 points (SD 8.87) to a final postoperative follow-up mean of 93.48 (SD 7.7). Cumulative success rate for both implants at 13 years, with aseptic loosening as the end point, was 97.05%, while for both implants at 13 years, with revision for any reason as the end point, it was 91.17%. Satisfactory results were observed with the use of this prosthesis. PMID:20041375

  18. The Latest Lessons Learned from Retrieval Analyses of Ultra-High Molecular Weight Polyethylene, Metal-on-Metal, and Alternative Bearing Total Disc Replacements

    PubMed Central

    Kurtz, Steven M.; Toth, Jeffrey M.; Siskey, Ryan; Ciccarelli, Lauren; MacDonald, Dan; Isaza, Jorge; Lanman, Todd; Punt, Ilona; Steinbeck, Marla; Goffin, Jan; van Ooij, André

    2012-01-01

    Knowledge regarding the in vivo performance and periposthetic tissue response of cervical and lumbar total disc replacements (TDRs) continues to expand. This review addresses the following four main questions: 1) What are the latest lessons learned from polyethylene in large joints and how are they relevant to current TDRs? 2) What are the latest lessons learned regarding adverse local tissue reactions from metal-on-metal, CoCr bearings in large joints and how are they relevant to current TDRs? 3) What advancements have been made in understanding the in vivo performance of alternative biomaterials, such as stainless steel and polycarbonate urethane, for TDRs in the past five years? 4) How has retrieval analysis of all these various artificial disc bearing technologies advanced the state of the art in preclinical testing of TDRs? The study of explanted artificial discs and their associated tissues can help inform bearing selection as well as the design of future generations of disc arthroplasty. Analyzing retrieved artificial discs is also essential for validating preclinical test methods. PMID:22904606

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

    PubMed Central

    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. PMID:23284597

  20. Effects of metals on the total lipid content in the gypsy moth (Lymantria dispar, Lymantriidae, Lepid.) and its hemolymph

    SciTech Connect

    Ortel, J.

    1995-08-01

    Previous work on the gypsy moth, Lymantria dispar, was focused on the influence of Cd, Pb, Cu and Zn on its life cycle (diverse vitality parameters), stage-specific accumulation potential and implications on one of its parasitoids Glyptapanteles liparidis. Results of these studies suggested that metal exposure of L. dispar at NOEC (No-Observed-Effect-concentration) levels may influence its hemolymph composition. We decided, therefore, to analyze the hemolymph composition for the main substance classes protein, lipids and carbohydrates of fourth instar larvae of L. dispar exposed to concentrations of Cd, Pb, Cu and Zn in the range of NOECs determined by Gintenreiter et al. (1993a). This study presents the first results of the determination of lipid concentration in the hemolymph of fourth instar larvae as well as of total lipid content of the corresponding larvae. 14 refs., 2 figs.

  1. Metal Ion Concentrations in Young, Active Patients Following Total Hip Arthroplasty with the Use of Modern Bearing Couples.

    PubMed

    Nam, Denis; Keeney, James A; Nunley, Ryan M; Johnson, Staci R; Clohisy, John C; Barrack, Robert L

    2015-12-01

    The purpose of this study was to compare whole blood metal ion levels in young, active patients undergoing primary total hip arthroplasty with the use of a cobalt-alloy (ten patients), ceramic (15 patients), or oxinium (11 patients) femoral head and highly crosslinked polyethylene acetabular liner. At 2 years postoperatively, mean cobalt concentrations were 3.0 times higher in the cobalt-alloy cohort versus the ceramic cohort, and 2.3 times higher versus the oxinium cohort (P=0.3-0.5). Titanium levels were consistently elevated at all postoperative time points versus preoperatively in all cohorts. Young, active patients following THA demonstrate elevated cobalt and titanium concentrations. Use of a ceramic or oxinium femoral head decreased the degree of cobalt elevation versus a cobalt-alloy femoral head, but did not reach statistical significance. PMID:26164561

  2. Intelligent Simultaneous Quantitative Online Analysis of Environmental Trace Heavy Metals with Total-Reflection X-Ray Fluorescence

    PubMed Central

    Ma, Junjie; Wang, Yeyao; Yang, Qi; Liu, Yubing; Shi, Ping

    2015-01-01

    Total-reflection X-ray fluorescence (TXRF) has achieved remarkable success with the advantages of simultaneous multi-element analysis capability, decreased background noise, no matrix effects, wide dynamic range, ease of operation, and potential of trace analysis. Simultaneous quantitative online analysis of trace heavy metals is urgently required by dynamic environmental monitoring and management, and TXRF has potential in this application domain. However, it calls for an online analysis scheme based on TXRF as well as a robust and rapid quantification method, which have not been well explored yet. Besides, spectral overlapping and background effects may lead to loss of accuracy or even faulty results during practical quantitative TXRF analysis. This paper proposes an intelligent, multi-element quantification method according to the established online TXRF analysis platform. In the intelligent quantification method, collected characteristic curves of all existing elements and a pre-estimated background curve in the whole spectrum scope are used to approximate the measured spectrum. A novel hybrid algorithm, PSO-RBFN-SA, is designed to solve the curve-fitting problem, with offline global optimization and fast online computing. Experimental results verify that simultaneous quantification of trace heavy metals, including Cr, Mn, Fe, Co, Ni, Cu and Zn, is realized on the online TXRF analysis platform, and both high measurement precision and computational efficiency are obtained. PMID:25954949

  3. Total neutron scattering investigation of the structure of a cobalt gallium oxide spinel prepared by solvothermal oxidation of gallium metal.

    PubMed

    Playford, Helen Y; Hannon, Alex C; Tucker, Matthew G; Lees, Martin R; Walton, Richard I

    2013-11-13

    A new solvothermal synthesis route to mixed-metal gallium oxides with the spinel structure has been developed for ternary oxides of ideal composition Ga(3-x)M(x)O(4-y) (M=Co, Zn, Ni). The structure of the novel cobalt gallate produced in this manner, Ga(1.767(8))Co(0.973(8))O(3.752(8)), has been determined from total neutron scattering to be a partially defective spinel with mixed-valent cobalt (approximately 25% Co(3+) and 75% Co(2+)) and with vacancies on approximately 6% of oxygen sites. Pair distribution function (PDF) analysis reveals significant local deviations from the average cubic structure, which are attributed to the conflicting coordination preferences of the Co(2+) (potential Jahn-Teller distortion) and Ga(3+) (Ga off-centring). Reverse Monte Carlo (RMC) modelling supports this conclusion since different metal-oxygen bond-distance distributions are found for the two cations in the refined configuration. An investigation of magnetic properties shows evidence of short-range magnetic order and spin-glass-like behaviour, consistent with the structural disorder of the material. PMID:24141264

  4. Intelligent simultaneous quantitative online analysis of environmental trace heavy metals with total-reflection X-ray fluorescence.

    PubMed

    Ma, Junjie; Wang, Yeyao; Yang, Qi; Liu, Yubing; Shi, Ping

    2015-01-01

    Total-reflection X-ray fluorescence (TXRF) has achieved remarkable success with the advantages of simultaneous multi-element analysis capability, decreased background noise, no matrix effects, wide dynamic range, ease of operation, and potential of trace analysis. Simultaneous quantitative online analysis of trace heavy metals is urgently required by dynamic environmental monitoring and management, and TXRF has potential in this application domain. However, it calls for an online analysis scheme based on TXRF as well as a robust and rapid quantification method, which have not been well explored yet. Besides, spectral overlapping and background effects may lead to loss of accuracy or even faulty results during practical quantitative TXRF analysis. This paper proposes an intelligent, multi-element quantification method according to the established online TXRF analysis platform. In the intelligent quantification method, collected characteristic curves of all existing elements and a pre-estimated background curve in the whole spectrum scope are used to approximate the measured spectrum. A novel hybrid algorithm, PSO-RBFN-SA, is designed to solve the curve-fitting problem, with offline global optimization and fast online computing. Experimental results verify that simultaneous quantification of trace heavy metals, including Cr, Mn, Fe, Co, Ni, Cu and Zn, is realized on the online TXRF analysis platform, and both high measurement precision and computational efficiency are obtained. PMID:25954949

  5. Predicting density functional theory total energies and enthalpies of formation of metal-nonmetal compounds by linear regression

    NASA Astrophysics Data System (ADS)

    Deml, Ann M.; O'Hayre, Ryan; Wolverton, Chris; Stevanović, Vladan

    2016-02-01

    The availability of quantitatively accurate total energies (Etot) of atoms, molecules, and solids, enabled by the development of density functional theory (DFT), has transformed solid state physics, quantum chemistry, and materials science by allowing direct calculations of measureable quantities, such as enthalpies of formation (Δ Hf ). Still, the ability to compute Etot and Δ Hf values does not, necessarily, provide insights into the physical mechanisms behind their magnitudes or chemical trends. Here, we examine a large set of calculated Etot and Δ Hf values obtained from the DFT+U -based fitted elemental-phase reference energies (FERE) approach [V. Stevanović, S. Lany, X. Zhang, and A. Zunger, Phys. Rev. B 85, 115104 (2012), 10.1103/PhysRevB.85.115104] to probe relationships between the Etot/Δ Hf of metal-nonmetal compounds in their ground-state crystal structures and properties describing the compound compositions and their elemental constituents. From a stepwise linear regression, we develop a linear model for Etot, and consequently Δ Hf , that reproduces calculated FERE values with a mean absolute error of ˜80 meV/atom. The most significant contributions to the model include calculated total energies of the constituent elements in their reference phases (e.g., metallic iron or gas phase O2), atomic ionization energies and electron affinities, Pauling electronegativity differences, and atomic electric polarizabilities. These contributions are discussed in the context of their connection to the underlying physics. We also demonstrate that our Etot/Δ Hf model can be directly extended to predict the Etot and Δ Hf of compounds outside the set used to develop the model.

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

    PubMed Central

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

    2016-01-01

    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. PMID:27345704

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2016-01-01

    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. PMID:27345704

  9. Metal bacteriochlorins which act as dual singlet oxygen and superoxide generators.

    PubMed

    Fukuzumi, Shunichi; Ohkubo, Kei; Zheng, Xiang; Chen, Yihui; Pandey, Ravindra K; Zhan, Riqiang; Kadish, Karl M

    2008-03-01

    A series of stable free-base, Zn(II) and Pd(II) bacteriochlorins containing a fused six- or five-member diketo- or imide ring have been synthesized as good candidates for photodynamic therapy sensitizers, and their electrochemical, photophysical, and photochemical properties were examined. Photoexcitation of the palladium bacteriochlorin affords the triplet excited state without fluorescence emission, resulting in formation of singlet oxygen with a high quantum yield due to the heavy atom effect of palladium. Electrochemical studies revealed that the zinc bacteriochlorin has the smallest HOMO-LUMO gap of the investigated compounds, and this value is significantly lower than the triplet excited-state energy of the compound in benzonitrile. Such a small HOMO-LUMO gap of the zinc bacteriochlorin enables intermolecular photoinduced electron transfer from the triplet excited state to the ground state to produce both the radical cation and the radical anion. The radical anion thus produced can transfer an electron to molecular oxygen to produce superoxide anion which was detected by electron spin resonance. The same photosensitizer can also act as an efficient singlet oxygen generator. Thus, the same zinc bacteriochlorin can function as a sensitizer with a dual role in that it produces both singlet oxygen and superoxide anion in an aprotic solvent (benzonitrile). PMID:18254618

  10. Controllable synthesis of metal selenide heterostructures mediated by Ag2Se nanocrystals acting as catalysts.

    PubMed

    Zhou, Jiangcong; Huang, Feng; Xu, Ju; Wang, Yuansheng

    2013-10-21

    Ag2Se nanocrystals were demonstrated to be novel semiconductor mediators, or in other word catalysts, for the growth of semiconductor heterostructures in solution. This is a result of the unique feature of Ag2Se as a fast ion conductor, allowing foreign cations to dissolve and then to heterogrow the second phase. Using Ag2Se nanocrystals as catalysts, dimeric metal selenide heterostructures such as Ag2Se-CdSe and Ag2Se-ZnSe, and even multi-segment heterostructures such as Ag2Se-CdSe-ZnSe and Ag2Se-ZnSe-CdSe, were successfully synthesized. Several interesting features were found in the Ag2Se based heterogrowth. At the initial stage of heterogrowth, a layer of the second phase forms on the surface of an Ag2Se nanosphere, with a curved junction interface between the two phases. With further growth of the second phase, the Ag2Se nanosphere tends to flatten the junction surface by modifying its shape from sphere to hemisphere in order to minimize the conjunct area and thus the interfacial energy. Notably, the crystallographic relationship of the two phases in the heterostructure varies with the lattice parameters of the second phase, in order to reduce the lattice mismatch at the interface. Furthermore, a small lattice mismatch at the interface results in a straight rod-like second phase, while a large lattice mismatch would induce a tortuous product. The reported results may provide a new route for developing novel selenide semiconductor heterostructures which are potentially applicable in optoelectronic, biomedical, photovoltaic and catalytic fields. PMID:24056899

  11. The contact mechanics and occurrence of edge loading in modular metal-on-polyethylene total hip replacement during daily activities.

    PubMed

    Hua, Xijin; Li, Junyan; Jin, Zhongmin; Fisher, John

    2016-06-01

    The occurrence of edge loading in hip joint replacement has been associated with many factors such as prosthetic design, component malposition and activities of daily living. The present study aimed to quantify the occurrence of edge loading/contact at the articulating surface and to evaluate the effect of cup angles and edge loading on the contact mechanics of a modular metal-on-polyethylene (MoP) total hip replacement (THR) during different daily activities. A three-dimensional finite element model was developed based on a modular MoP bearing system. Different cup inclination and anteversion angles were modelled and six daily activities were considered. The results showed that edge loading was predicted during normal walking, ascending and descending stairs activities under steep cup inclination conditions (≥55°) while no edge loading was observed during standing up, sitting down and knee bending activities. The duration of edge loading increased with increased cup inclination angles and was affected by the cup anteversion angles. Edge loading caused elevated contact pressure at the articulating surface and substantially increased equivalent plastic strain of the polyethylene liner. The present study suggested that correct positioning the component to avoid edge loading that may occur during daily activities is important for MoP THR in clinical practice. PMID:27056255

  12. A Finite-Element Study of Metal Backing and Tibial Resection Depth in a Composite Tibia Following Total Knee Arthroplasty.

    PubMed

    Tokunaga, Susumu; Rogge, Renee D; Small, Scott R; Berend, Michael E; Ritter, Merrill A

    2016-04-01

    Prosthetic alignment, patient characteristics, and implant design are all factors in long-term survival of total knee arthroplasty (TKA), yet the level at which each of these factors contribute to implant loosening has not been fully described. Prior clinical and biomechanical studies have indicated tibial overload as a cause of early TKA revision. The purpose of this study was to determine the relationship between tibial component design and bone resection on tibial loading. Finite-element analysis (FEA) was performed after simulated implantation of metal backed (MB) and all-polyethylene (AP) TKA components in 5 and 15 mm of tibial resection into a validated intact tibia model. Proximal tibial strains significantly increased between 13% and 199% when implanted with AP components (p < 0.05). Strain significantly increased between 12% and 209% in the posterior tibial compartment with increased bone resection (p < 0.05). This study indicates elevated strains in AP implanted tibias across the entirety of the proximal tibial cortex, as well as a posterior shift in tibial loading in instances of increased resection depth. These results are consistent with trends observed in prior biomechanical studies and may associate the documented device history of tibial collapse in AP components with increased bone strain and overload beneath the prosthesis. PMID:26810930

  13. Similar incidence of periprosthetic fluid collections after ceramic-on-polyethylene total hip arthroplasties and metal-on-metal resurfacing arthroplasties: results of a screening metal artefact reduction sequence-MRI study.

    PubMed

    Bisseling, P; de Wit, B W K; Hol, A M; van Gorp, M J; van Kampen, A; van Susante, J L C

    2015-09-01

    Patients from a randomised trial on resurfacing hip arthroplasty (RHA) (n = 36, 19 males; median age 57 years, 24 to 65) comparing a conventional 28 mm metal-on-metal total hip arthroplasty (MoM THA) (n = 28, 17 males; median age 59 years, 37 to 65) and a matched control group of asymptomatic patients with a 32 mm ceramic-on-polyethylene (CoP) THA (n = 33, 18 males; median age 63 years, 38 to 71) were cross-sectionally screened with metal artefact reducing sequence-MRI (MARS-MRI) for pseudotumour formation at a median of 55 months (23 to 72) post-operatively. MRIs were scored by consensus according to three different classification systems for pseudotumour formation. Clinical scores were available for all patients and metal ion levels for MoM bearing patients. Periprosthetic lesions with a median volume of 16 mL (1.5 to 35.9) were diagnosed in six patients in the RHA group (17%), one in the MoM THA group (4%) and six in the CoP group (18%). The classification systems revealed no clear differences between the groups. Solid lesions (n = 3) were exclusively encountered in the RHA group. Two patients in the RHA group and one in the MoM THA group underwent a revision for pseudotumour formation. There was no statistically significant relationship between clinical scoring, metal ion levels and periprosthetic lesions in any of the groups. Periprosthetic fluid collections are seen on MARS-MRI after conventional CoP THA and RHA and may reflect a soft-tissue collection or effusion. Currently available MRI classification systems seem to score these collections as pseudotumours, causing an-overestimatation of the incidence of pseudotumours. PMID:26330582

  14. Poor mid-term survival of the low-carbide metal-on-metal Zweymüller-plus total hip arthroplasty system: a concise follow-up, at a minimum of ten years, of a previous report*.

    PubMed

    Repantis, Thomas; Vitsas, Vasilis; Korovessis, Panagiotis

    2013-03-20

    Between 1994 and 1999, 217 metal-on-metal total hip arthroplasties with a low-carbide bearing surface were performed with use of the cementless Zweymüller SL-Plus stem and the Bicon-Plus threaded cup in 194 consecutive patients. After a minimum follow-up of ten years, 181 living patients (203 hips) were available for evaluation. The revision rate after an average of twelve years was 18% (thirty-six hips in thirty-six patients were revised). The main reason for revision was aseptic loosening of one or both components. The probability of survival of the stem at fifteen years was 77% (95% confidence interval [CI], 65% to 86%). The probability of survival of the cup was 80% (95% CI, 62% to 90%). These high failure rates at mid-term follow-up led us to abandon the use of low-carbide metal-on-metal total hip arthroplasty components. PMID:23515994

  15. USEPA METHOD STUDY 35 - SW-846 METHOD 3005, ACID DIGESTION OF WATERS FOR TOTAL RECOVERABLE OR DISSOLVED METALS FOR ANALYSES BY FLAME ATOMIC ABSORPTION SPECTROSCOPY

    EPA Science Inventory

    An interlaboratory collaborative study was conducted to determine the precision and bias (recovery) of Solid Waste (SW) Method 3005 for the analysis of 21 elements in ground water. SW Method 3005 is entitled, "Acid Digestion of Waters for Total Recoverable Metals for Analyses by ...

  16. Status of metal contamination in surface waters of the coastal ocean off Los Angeles, California since the implementation of the Clean Water Act.

    PubMed

    Smail, Emily A; Webb, Eric A; Franks, Robert P; Bruland, Kenneth W; Sañudo-Wilhelmy, Sergio A

    2012-04-17

    In order to establish the status of metal contamination in surface waters in the coastal ocean off Los Angeles, California, we determined their dissolved and particulate pools and compared them with levels reported in the 1970s prior the implementation of the Clean Water Act. These measurements revealed a significant reduction in particulate toxic metal concentrations in the last 33 years with decreases of ∼100-fold for Pb and ∼400-fold for Cu and Cd. Despite these reductions, the source of particulate metals appears to be primarily anthropogenic as enrichment factors were orders of magnitude above what is considered background crustal levels. Overall, dissolved trace metal concentrations in the Los Angeles coastal waters were remarkably low with values in the same range as those measured in a pristine coastal environment off Mexico's Baja California peninsula. In order to estimate the impact of metal contamination on regional phytoplankton, the internalization rate of trace metals in a locally isolated phytoplankton model organism (Synechococcus sp. CC9311) was also determined showing a rapid internalization (in the order of a few hours) for many trace metals (e.g., Ag, Cd, Cu, Pb) suggesting that those metals could potentially be incorporated into the local food webs. PMID:22420576

  17. Structural evolution across the insulator-metal transition in oxygen-deficient BaTiO3-δ studied using neutron total scattering and Rietveld analysis

    DOE PAGESBeta

    Jeong, I.-K.; Lee, Seunghun; Jeong, Se-Young; Won, C. J.; Hur, N.; Llobet, A.

    2011-08-29

    Oxygen-deficient BaTiO3-δ exhibits an insulator-metal transition with increasing δ. We performed neutron total scattering measurements to study structural evolution across an insulator-metal transition in BaTiO3-δ. Despite its significant impact on resistivity, slight oxygen reduction (δ=0.09) caused only a small disturbance on the local doublet splitting of Ti-O bond. This finding implies that local polarization is well preserved under marginal electric conduction. In the highly oxygen-deficient metallic state (δ=0.25), however, doublet splitting of the Ti-O bond became smeared. The smearing of the local Ti-O doublet is complemented with long-range structural analysis and demonstrates that the metallic conduction in the highly oxygen-reducedmore » BaTiO3-δ is due to the appearance of nonferroelectric cubic lattice.« less

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

    PubMed Central

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

    2010-01-01

    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. PMID:20948927

  19. Size Distribution and Estimated Respiratory Deposition of Total Chromium, Hexavalent Chromium, Manganese, and Nickel in Gas Metal Arc Welding Fume Aerosols

    PubMed Central

    Cena, Lorenzo G.; Chisholm, William P.; Keane, Michael J.; Cumpston, Amy; Chen, Bean T.

    2016-01-01

    A laboratory study was conducted to determine the mass of total Cr, Cr(VI), Mn, and Ni in 15 size fractions for mild and stainless steel gas-metal arc welding (GMAW) fumes. Samples were collected using a nano multi orifice uniform deposition impactor (MOUDI) with polyvinyl chloride filters on each stage. The filters were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and ion chromatography. Limits of detection (LODs) and quantitation (LOQs) were experimentally calculated and percent recoveries were measured from spiked metals in solution and dry, certified welding-fume reference material. The fraction of Cr(VI) in total Cr was estimated by calculating the ratio of Cr(VI) to total Cr mass for each particle size range. Expected, regional deposition of each metal was estimated according to respiratory-deposition models. The weight percent (standard deviation) of Mn in mild steel fumes was 9.2% (6.8%). For stainless steel fumes, the weight percentages were 8.4% (5.4%) for total Cr, 12.2% (6.5%) for Mn, 2.1% (1.5%) for Ni and 0.5% (0.4%) for Cr(VI). All metals presented a fraction between 0.04 and 0.6 μm. Total Cr and Ni presented an additional fraction <0.03 μm. On average 6% of the Cr was found in the Cr(VI) valence state. There was no statistical difference between the smallest and largest mean Cr(VI) to total Cr mass ratio (p-value D 0.19), hence our analysis does not show that particle size affects the contribution of Cr(VI) to total Cr. The predicted total respiratory deposition for the metal particles was ∼25%. The sites of principal deposition were the head airways (7–10%) and the alveolar region (11–14%). Estimated Cr(VI) deposition was highest in the alveolar region (14%). PMID:26848207

  20. Presence of corrosion products and hypersensitivity-associated reactions in periprosthetic tissue after aseptic loosening of total hip replacements with metal bearing surfaces.

    PubMed

    Huber, Monika; Reinisch, Georg; Trettenhahn, Günter; Zweymüller, Karl; Lintner, Felix

    2009-01-01

    Aseptic loosening of articular implants is frequently associated with tissue reactions to wear particles. Some patients, who had received metal-on-metal articulations, present early symptoms including persistent pain and implant failure. These symptoms raise the suspicion about the development of an immunological response. Furthermore, the generation of rare corrosion products in association with metallic implants has been observed. Corrosion products are known to enhance third-body wear and contribute to the loss of the implant. The purpose of this study was to investigate periprosthetic tissue containing solid corrosion products after aseptic loosening of second-generation metal-on-metal total hip replacements made of low-carbon cobalt-chromium-molybdenum alloy for the presence of immunologically determined tissue changes. Periprosthetic tissue of 11 cases containing uncommon solid deposits was investigated by light microscopy. In order to confirm the presence of corrosion products, additional methods including scanning electron microscopy (SEM) investigation, energy dispersive X-ray (EDX) and Fourier transform infrared microspectroscopy (FTIR) analysis were used. All investigated cases revealed solid chromium orthophosphate corrosion products as well as metallic wear particles to a various extent. Moreover, various intense tissue reactions characteristic of immune response were observed in all cases. The simultaneous presence of corrosion products and hypersensitivity-associated tissue reaction indicates that a relationship between corrosion development and implant-related hypersensitivity may exist. PMID:18725188

  1. 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.

    PubMed

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

    2015-11-01

    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 head (38 mm to 60 mm) cementless MoM THA with conventional head (28 mm) cementless MoP THA, 93 patients (96 THAs: 41 MoM (21 males, 20 females, mean age of 64 years, standard deviation (sd) 4) and 55 MoP (25 males, 30 females, mean age of 65 years, sd 5) were recruited after a mean follow-up of 50 months (36 to 64). The incidence of pseudotumours, measured using a standardised CT protocol was 22 (53.7%) after MoM THA and 12 (21.8%) after MoP THA. Women with a MoM THA were more likely to develop a pseudotumour than those with a MoP THA (15 vs 7, odds ratio (OR) = 13.4, p < 0.001). There was a similar incidence of pseudotumours in men with MoM THAs and those with MoP THAs (7 vs 5, OR = 2.1, p = 0.30). Elevated cobalt levels (≥ 5 microgram/L) were only associated with pseudotumours in women with a MoM THA. There was no difference in mean Oxford and Harris hip scores between patients with a pseudotumour and those without. Contrary to popular belief, pseudotumours occur frequently around MoP THAs. Women with a MoM THA and an elevated cobalt level are at greatest risk. In this study, pseudotumours had no effect on the functional outcome after either large head MoM or conventional MoP THA. PMID:26530649

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

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

    2015-11-14

    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 Au(100-x)Pd(x) (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. PMID:26463562

  4. ADSORPTION OF CADMIUM ONTO ORGANIC, TOTAL INORGANIC, AND METAL OXIDE FRACTIONS IN BIOSOLIDS AND BIOSOLID-AMENDED SOILS

    EPA Science Inventory

    The environmental impact and potential hazards of metals in biosolids to plants, animals and the human food chain from biosolids application on soils has been studied for decades. The early hypothesis known as "Time Bomb" has been questioned by recent research results which tend ...

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

    PubMed

    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 (<4%). According with the total metal concentrations, background levels and normalised enrichment factors (NEF) of the metals studied, the impact of the Peña Colorada iron mine on the Marabasco system is lower than expected when compared with other similar World systems influenced by mining activities. PMID:17997460

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

    SciTech Connect

    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.

  7. Application of patent bio-rack wetland system using Phragmites sp. for domestic wastewater treatment in the presence of high total dissolved solids (TDS) and heavy metal salts.

    PubMed

    Valipour, Alireza; Raman, V Kalyan; Ghole, V S

    2011-07-01

    The quality of water recourses is degrading due to improper wastewater management. The aim of this study is to examine the potential of bio-rack system for treatment of domestic wastewater in the presence of high total dissolved solids (TDS) and heavy metal salts. The bio-rack is a modified wetland system incorporated with the advantages of phytoremediation and attached growth microbial process. The bio-rack is void of the soil strata based root zone system and in lieu a support matrix is provided to enrich the micro flora. The studies indicate that, Phragmites sp. can tolerate TDS up to 9000 mg/L in the bio-rack. The heavy metal removal is a function of phytoaccumulation or phytoextraction, which can lead to morphological deformity if heavy metals exceed the saturation limit of 786 and 5760 mg/kg Cd, 854 and 9280 mg/kg Cu, 639 and 4720 mg/kg Ni, 1187 and 7516 mg/kg Zn, in shoots and roots respectively. The reduction in TDS is marginal (14%) at the highest tolerable limit whereas the heavy metal reduction is 68%, 69%, 67%, 71% for Cd, Cu, Ni and Zn respectively at the outlet of the treatment system. The sewage treatment performance of the bio-rack system for all other parameters is estimated as 75 % Chemical Oxygen Demand (COD), 86 % Biological Oxygen Demand (BOD5), 27% Total Dissolved Solids (TDS), 73% Total Suspended Solids (TSS), 9% chlorides, 70% ammonia nitrogen (NH3-N), 32% phosphate (PO4-P), 92% most probable number (MPN) and 93% total viable count (TVC) reduction. PMID:23029929

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

    SciTech Connect

    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

    2012-10-01

    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.

  9. Total synthesis of buckminsterfullerene (C60) and endohedral metal complexes. Final report, 1 March 1994-28 February 1997

    SciTech Connect

    Rubin, Y.F.

    1997-08-11

    A summary of our work aimed at the synthesis of a variety of endohedral metal complexes of fullerenes is presented. The completion of the synthesis of suitable highly unsaturated macrocyclic precursors containing 60 carbon atoms is described. These compounds were required to study their rearrangement to a fullerene framework in a process analogous to the gas-phase rearrangement of mono- and polycyclic polyynes (acetylenic rings) in the formation of C60 and higher fullerenes. Three types of synthetic acetylenic precursors were targeted, namely triply-linked bis-benzene-cyclophanes with octayne linking units, sextuply-linked bis-benzene-cyclophanes with tetrayne linkers, and deca-alkynylated metallocenes which include a metal in their structure early in the synthesis. The rearrangement to C60 of the first examples of these compounds has been studied in the gas phase by LDMS and in solution by various chemical reactions. Another aspect of our work was initiated by the successful opening of the largest orifice on the framework of C60 known to date in the form of a cobalt(III) complex of ethenobisfulleroid C64H4. This strategy is being applied in a double fashion on adjacent sites of the surface of C60 to form an even larger opening, aimed at eventual metal insertion inside the cage.

  10. Cross-shear implementation in sliding-distance-coupled finite element analysis of wear in metal-on-polyethylene total joint arthroplasty: intervertebral total disc replacement as an illustrative application.

    PubMed

    Goreham-Voss, Curtis M; Hyde, Philip J; Hall, Richard M; Fisher, John; Brown, Thomas D

    2010-06-18

    Computational simulations of wear of orthopaedic total joint replacement implants have proven to valuably complement laboratory physical simulators, for pre-clinical estimation of abrasive/adhesive wear propensity. This class of numerical formulations has primarily involved implementation of the Archard/Lancaster relationship, with local wear computed as the product of (finite element) contact stress, sliding speed, and a bearing-couple-dependent wear factor. The present study introduces an augmentation, whereby the influence of interface cross-shearing motion transverse to the prevailing molecular orientation of the polyethylene articular surface is taken into account in assigning the instantaneous local wear factor. The formulation augment is implemented within a widely utilized commercial finite element software environment (ABAQUS). Using a contemporary metal-on-polyethylene total disc replacement (ProDisc-L) as an illustrative implant, physically validated computational results are presented to document the role of cross-shearing effects in alternative laboratory consensus testing protocols. Going forward, this formulation permits systematically accounting for cross-shear effects in parametric computational wear studies of metal-on-polyethylene joint replacements, heretofore a substantial limitation of such analyses. PMID:20399432

  11. Cross-Shear Implementation in Sliding-Distance-Coupled Finite Element Analysis of Wear in Metal-on-Polyethylene Total Joint Arthroplasty: Intervertebral Total Disc Replacement as an Illustrative Application

    PubMed Central

    Goreham-Voss, Curtis M.; Hyde, Philip J.; Hall, Richard M.; Fisher, John; Brown, Thomas D.

    2010-01-01

    Computational simulations of wear of orthopaedic total joint replacement implants have proven to valuably complement laboratory physical simulators, for pre-clinical estimation of abrasive/adhesive wear propensity. This class of numerical formulations has primarily involved implementation of the Archard/Lancaster relationship, with local wear computed as the product of (finite element) contact stress, sliding speed, and a bearing-couple-dependent wear factor. The present study introduces an augmentation, whereby the influence of interface cross-shearing motion transverse to the prevailing molecular orientation of the polyethylene articular surface is taken into account in assigning the instantaneous local wear factor. The formulation augment is implemented within a widely-utilized commercial finite element software environment (ABAQUS). Using a contemporary metal-on-polyethylene total disc replacement (ProDisc-L) as an illustrative implant, physically validated computational results are presented to document the role of cross-shearing effects in alternative laboratory consensus testing protocols. Going forward, this formulation permits systematically accounting for cross-shear effects in parametric computational wear studies of metal-on-polyethylene joint replacements, heretofore a substantial limitation of such analyses. PMID:20399432

  12. Theoretical differential Raman scattering cross-sections of totally-symmetric vibrational modes of free pyridine and pyridine-metal cluster complexes

    NASA Astrophysics Data System (ADS)

    Wu, D. Y.; Hayashi, M.; Lin, S. H.; Tian, Z. Q.

    2004-01-01

    The differential Raman scattering cross-sections of totally-symmetric vibrational modes for pyridine and pyridine-metal clusters have been calculated by using ab initio and density functional methods. The results are compared with experimental data and a good agreement is obtained. In particular, we can theoretically reproduce the significant changes in the relative Raman intensities of the ν12 mode in pyridine-metal cluster complexes. We focus on two mechanisms for these Raman intensities changes: (1) the chemical interaction between the pyridine and the metal clusters; and (2) the charge transfer mechanism. For the pyridine-silver cluster complexes, we find that due to the weak bonding, the chemical interaction does not influence the relative intensities of the Raman peaks of the ν1 and ν12 modes. However, in the case where the copper or the gold clusters are attached to pyridine, the intensity of the band of the ν12 mode is weakened significantly. We also find that the charge transfer mechanism increases the asymmetry of the bands of the ν1 and ν12 modes on all three metals.

  13. Pseudotumour formation and subsequent resolution in metal-on-metal total hip arthroplasty following revision: Instructional review and an illustrative case report with revision using a dual mobility design.

    PubMed

    Sassoon, A A; Barrack, R L

    2016-06-01

    The use of large-diameter metal-on-metal (MoM) components in total hip arthroplasty (THA) is associated with an increased risk of early failure due to adverse local tissue reaction to metal debris (ARMD) in response to the release of metal ions from the bearing couple and/or head-neck taper corrosion. The aim of this paper was to present a review of the incidence and natural history of ARMD and the forms of treatment, with a focus on the need for and extent of resection or debulking of the pseudotumour. An illustrative case report is presented of a patient with an intra-pelvic pseudotumour associated with a large diameter MoM THA, which was treated successfully with revision of the bearing surface to a dual mobility couple and retention of the well-fixed acetabular and femoral components. The pseudotumour was left in situ Resolution of the intra-pelvic mass and normalisation of metal ion levels was observed seven months post-operatively. Cite this article: Bone Joint J 2016;98-B:736-40. PMID:27235513

  14. On-site analysis of heavy metal contaminated areas by means of total reflection X-ray fluorescence analysis (TXRF)

    NASA Astrophysics Data System (ADS)

    Stosnach, Hagen

    2006-11-01

    In this paper the possibilities and restriction for applying the low power TXRF spectrometer PicoTAX for the one-site analysis of heavy metal contaminated soils and sediments are evaluated. Basis for this evaluation is the Superfund Innovative Technology Evaluation (SITE) program, conducted by the U.S. Environmental Protection Protection Agency (US EPA). During a measurement campaign, performed under realistic conditions, 320 soil and sediment samples were analyzed. The task was the fast analysis of the main target elements antimony, arsenic, cadmium, chromium, copper, iron, lead, mercury, nickel, selenium, silver, vanadium, and zinc. These elements were present in wide ranging concentrations. Out of a set of seven primary and five secondary objectives the method detection limits, accuracy and precision of the TXRF measurements are discussed. In addition to the on-site measurements, the application of TXRF analysis for the analysis of soil- and sediment samples after complete microwave assisted acid digestion is reported. Recent instrument improvements have distinctly increased the quality of measurement results. A detailed description of these new developments and new measurement results are discussed

  15. In-vivo 6 degrees-of-freedom kinematics of metal-on-polyethylene total hip arthroplasty during gait.

    PubMed

    Tsai, Tsung-Yuan; Li, Jing-Sheng; Wang, Shaobai; Scarborough, Donna; Kwon, Young-Min

    2014-05-01

    Knowledge of accurate in-vivo 6 degree-of-freedom (6-DOF) kinematics of total hip arthroplasty (THA) during daily activities is critical for improvement of longevity of the components. Previous studies assessed in-vivo THA kinematics using skin marker-based motion analysis. However, skin markers are prone to move with respect to the underlying bones. A non-invasive dual fluoroscopic imaging system (DFIS) based tracking technique has been used to avoid skin artifacts and provide accurate 6-DOF kinematic measurement. This study aimed to quantify in-vivo 6-DOF THA kinematics during gait using DFIS. Twenty eight well-functioning THAs were evaluated during treadmill gait under DFIS surveillance. The maximum translations of the femoral head were 0.46±0.10mm and 0.45±0.10mm during the stance and swing phases (p=0.57), respectively. The range of hip flexion was from 8.7° to 47.6°, adduction from 3.0° to 12.5° and external rotation from 19.2° to 29.7°. The THA was flexed, externally rotated and adducted throughout the gait. The magnitudes of the femoral head translations were found to be within the manufacture tolerance of the components, suggesting that in-vivo hip "pistoning" during gait cycle may be minimal in well-functioning THAs. The 6-DOF kinematics could be used as the baseline knowledge for further improvement of wear-testing of hip implant, implants manufacturing and implant positioning during surgery. PMID:24704170

  16. Risk of revision following total hip arthroplasty: metal-on-conventional polyethylene compared with metal-on-highly cross-linked polyethylene bearing surfaces: international results from six registries.

    PubMed

    Paxton, Elizabeth; Cafri, Guy; Havelin, Leif; Stea, Susanna; Pallisó, Francesc; Graves, Stephen; Hoeffel, Daniel; Sedrakyan, Art

    2014-12-17

    The results of randomized controlled trials and systematic reviews have suggested reduced radiographic wear in highly cross-linked polyethylene compared with conventional polyethylene in primary total hip arthroplasty. However, longer-term clinical results have not been thoroughly examined, to our knowledge. The purpose of this study was to compare the risk of revision for metal-on-conventional and metal-on-highly cross-linked total hip arthroplasty bearing surfaces with use of a distributed data network of six national and regional registries (Kaiser Permanente, HealthEast, the Emilia-Romagna region in Italy, the Catalan region in Spain, Norway, and Australia). Inclusion criteria were osteoarthritis as the primary diagnosis, cementless implant fixation, and a patient age of forty-five to sixty-four years. These criteria resulted in a sample of 16,571 primary total hip arthroplasties. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. The results of a fixed-effects model suggested that there was insufficient evidence of a difference in risk of revision between bearing surfaces (hazard ratio, 1.20 [95% confidence interval, 0.80 to 1.79]; p = 0.384). Highly cross-linked polyethylene does not appear to have a reduced risk of revision in this subgroup of total hip arthroplasty patients. Arthroplasties involving highly cross-linked polyethylene do not appear to have an increased risk of revision in this subgroup of total hip arthroplasty patients. PMID:25520415

  17. The Potential Impact of Increased Phosphorus Loads in Lakes Acting as Heavy Metal Reservoirs: A case study from west-central Indiana

    NASA Astrophysics Data System (ADS)

    McLennan, D. A.; Latimer, J. C.; Smith, E.; Stone, J.

    2015-12-01

    Green Valley Lake is a designated state fishing area in west-central Indiana. Prior to this designation, the lake was a water supply reservoir for the adjacent and now abandoned Green Valley Coal Mine (Operating from 1948-1963). The Green Valley Coal Mine property continues to produce excess acidity despite reclamation efforts. The former mine property and the lake are connected by a channel that discharges acidic drainage directly into Green Valley Lake. To evaluate temporal variability in metal and phosphorus (P) geochemistry, two short cores were collected in spring 2014 (38cm) and spring 2015 (39cm). Metal concentrations were determined by a hand-held X-ray fluorescence analyzer after the samples had been dried and crushed. Approximately 20% of these metal concentrations will be verified by ICP-OES following extraction in 50% aqua regia. Detailed P geochemistry was determined using a sequential extraction technique (SEDEX). The sediments in Green Valley Lake are characterized by heavy metal concentrations that are elevated above typical background levels. These metals tend to be concentrated near the sediment water interface, often 3-5 times greater than the average concentration for the rest of the core, which suggests that they are diagenetically mobile and possibly diffusing out of the sediments under dysoxic to anoxic conditions and returning to the sediments under oxic conditions. Total sedimentary P averages 57 umol/g, but oscillates between 20 - 110 umol/g. The most dramatic shift in the detailed P geochemistry is the significant reduction of mineral P at 15 cm and the increasing importance of oxide-associated and adsorbed P upcore. Diatom assemblages suggest that the lake has become increasingly more eutrophic over time. As nutrient loads continue to increase, the oxygen depleted zone may expand impacting fish populations and changing water geochemistry significantly, in particular, mobilizing heavy metals.

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    Zhang, Huyuan; Zhang, Qing; Yang, Bo; Wang, Jinfang

    2014-01-01

    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. PMID:24979755

  20. Compacted Sewage Sludge as a Barrier for Tailings: The Heavy Metal Speciation and Total Organic Carbon Content in the Compacted Sludge Specimen

    PubMed Central

    Zhang, Huyuan; Zhang, Qing; Yang, Bo; Wang, Jinfang

    2014-01-01

    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. PMID:24979755

  1. Synthesis-atomic structure-properties relationships in metallic nanoparticles by total scattering experiments and 3D computer simulations: case of Pt-Ru nanoalloy catalysts.

    PubMed

    Prasai, Binay; Ren, Yang; Shan, Shiyao; Zhao, Yinguang; Cronk, Hannah; Luo, Jin; Zhong, Chuan-Jian; Petkov, Valeri

    2015-05-01

    An approach to determining the 3D atomic structure of metallic nanoparticles (NPs) in fine detail and using the unique knowledge obtained for rationalizing their synthesis and properties targeted for optimization is described and exemplified on Pt-Ru alloy NPs of importance to the development of devices for clean energy conversion such as fuel cells. In particular, PtxRu100-x alloy NPs, where x = 31, 49 and 75, are synthesized by wet chemistry and activated catalytically by a post-synthesis treatment involving heating under controlled N2-H2 atmosphere. So-activated NPs are evaluated as catalysts for gas-phase CO oxidation and ethanol electro-oxidation reactions taking place in fuel cells. Both as-synthesized and activated NPs are characterized structurally by total scattering experiments involving high-energy synchrotron X-ray diffraction coupled to atomic pair distribution functions (PDFs) analysis. 3D structure models both for as-synthesized and activated NPs are built by molecular dynamics simulations based on the archetypal for current theoretical modelling Sutton-Chen method. Models are refined against the experimental PDF data by reverse Monte Carlo simulations and analysed in terms of prime structural characteristics such as metal-to-metal bond lengths, bond angles and first coordination numbers for Pt and Ru atoms. Analysis indicates that, though of a similar type, the atomic structure of as-synthesized and respective activated NPs differ in several details of importance to NP catalytic properties. Structural characteristics of activated NPs and data for their catalytic activity are compared side by side and strong evidence found that electronic effects, indicated by significant changes in Pt-Pt and Ru-Ru metal bond lengths at NP surface, and practically unrecognized so far atomic ensemble effects, indicated by distinct stacking of atomic layers near NP surface and prevalence of particular configurations of Pt and Ru atoms in these layers, contribute to the

  2. The nutrient, total petroleum hydrocarbon and heavy metal contents in the seawater of Bohai Bay, China: Temporal-spatial variations, sources, pollution statuses, and ecological risks.

    PubMed

    Peng, Shitao

    2015-06-15

    Seawater samples collected between 2007 and 2012 were determined the concentrations of nutrient (DIN and DIP), total petroleum hydrocarbon (TPH), and six different heavy metals (As, Cu, Zn, Pb, Cd and Hg). The DIN, DIP, TPH, Pb, and Cd concentrations decreased from 2007 to 2009 or 2010 and increased after 2010. However, the Hg and Cu concentrations increased from 2007 to 2012. In contrast, the As and Zn gradually decreased during the study period. All of the pollutant concentrations gradually decreased from the shoreline to the offshore sites. PCA result showed that urban and port areas, agriculture, and atmospheric deposition were the main sources of pollutants in the bay. Although most of the pollutants were present at concentrations bellow the highest seawater quality standards in China, eutrophication was a risk in Bohai Bay. In addition, DIN was the main pollutant and was responsible for the eutrophication risk in Bohai Bay. PMID:25840871

  3. Ultrasound-assisted single extraction tests for rapid assessment of metal extractability from soils by total reflection X-ray fluorescence.

    PubMed

    De La Calle, I; Cabaleiro, N; Lavilla, I; Bendicho, C

    2013-09-15

    In this work, ultrasound-assisted extraction (UAE) was employed for acceleration of metal extraction from soil samples. After extraction, multielemental analysis (Cr, Mn, Fe, Ni, Cu, Zn and Pb) of EDTA and acetic acid extracts was performed by total reflection X-ray fluorescence spectrometry (TXRF). High-intensity ultrasonic processors, i.e. the ultrasonic probe (50W) and the cup-horn sonoreactor (200W) were applied. Both ultrasonic procedures were compared with a miniaturized version of the single extraction scheme proposed by the Standards, Measurements and Testing program (SM&T). The extraction time with EDTA was reduced from 1h (conventional procedure) to 2 min (ultrasonic probe) or to 10 min (cup-horn sonoreactor). The time required for acetic acid extraction was also reduced from 16 h (conventional procedure) to 6 min (ultrasonic probe) or to 30 min (cup-horn sonoreactor). In addition, the amount of sample and extractants was drastically reduced as a result of the miniaturization implemented in the developed approaches. The combination of UAE and TXRF allows assessing the potential metal mobility and bioavailability in a simple way. PMID:23770487

  4. Measurements of Total Hemispherical Emissivity of Several Stably Oxidized Nickel-Titanium Carbide Cemented Hard Metals from 600 F to 1,600 F

    NASA Technical Reports Server (NTRS)

    Wade, William R.; Casey, F. W., Jr.

    1959-01-01

    The total hemispherical emissivity of several nickel-titanium carbide cemented hard metals have been measured over a temperature range from 600 F to l,600 F. A variety of cemented hard metals were obtained from the Kennametal Corporation. A brief discussion of the apparatus employed and the procedures used for this investigation is included. The results of the tests of specimens in the as-received and polished states indicate a nearly constant emissivity for each material tested over the temperature range considered and only slight differences in emissivity values for the different materials. Values obtained on the stably oxidized specimens range from 0.90 to 0.94 at 6000 F and o.88 to 0.92 at 1,600 F for the as-received specimens and from 0.82 to 0.89 at 600 F and 0.85 to 0.87 at 1,600 F for the polished specimens. The surface analysis of the oxidized materials as obtained by X-ray diffraction methods and metallographic techniques are presented as an aid to reproducing the surface on which these measurements were made.

  5. In situ induced metal-enhanced fluorescence: a new strategy for biosensing the total acetylcholinesterase activity in sub-microliter human whole blood.

    PubMed

    Ma, KeKe; Lu, Lu; Qi, Zongli; Feng, Jingjing; Zhuo, Caixia; Zhang, Yaodong

    2015-06-15

    Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities (i.e., total AChE) in human blood are biomarkers for theranostic monitoring of organophosphate neurotoxin-poisoned patients. We developed an ultra-sensitive method to detect the total AChE activity in sub-microliter human whole blood based on in situ induced metal-enhanced fluorescence (MEF). Both AChE and BChE can catalyze the hydrolysis of the acetylthiocholine (ATCh) substrate and produce positively-charged thiocholine (TCh). TCh can reverse the negatively-charged surface of core-shell Ag@SiO2 nanoparticles (NPs). The negatively-charged fluorescent dye (8-hydroxypyrene-1,3,6-trisulfonic acid, HPTS) is then confined to the surface of Ag@SiO2 NPs and generates an enhanced fluorescence signal in situ. Changes in the surface charge of Ag@SiO2 NPs are monitored by Zeta potential, and the MEF effect is confirmed by the measurements of fluorescence time decay. AChE activity has a dynamic range of 0 U/mL to 0.005 U/mL and a detection limit of 0.05 mU/mL. The total AChE activity in the sub-microliter human whole blood could be determined; the results were further validated. Therefore, combining the AChE catalytic reaction with MEF provides a simple, ultra-sensitive, and cost-effective "in situ MEF" approach to determine the total AChE activity in human whole blood sample down to sub-microliters without matrix interferences. The strategy also allows potential usage in other tissues and other fields. PMID:25660508

  6. Total Body Irradiation, Toward Optimal Individual Delivery: Dose Evaluation With Metal Oxide Field Effect Transistors, Thermoluminescence Detectors, and a Treatment Planning System

    SciTech Connect

    Bloemen-van Gurp, Esther J. Mijnheer, Ben J.; Verschueren, Tom A.M.; Lambin, Philippe

    2007-11-15

    Purpose: To predict the three-dimensional dose distribution of our total body irradiation technique, using a commercial treatment planning system (TPS). In vivo dosimetry, using metal oxide field effect transistors (MOSFETs) and thermoluminescence detectors (TLDs), was used to verify the calculated dose distributions. Methods and Materials: A total body computed tomography scan was performed and loaded into our TPS, and a three-dimensional-dose distribution was generated. In vivo dosimetry was performed at five locations on the patient. Entrance and exit dose values were converted to midline doses using conversion factors, previously determined with phantom measurements. The TPS-predicted dose values were compared with the MOSFET and TLD in vivo dose values. Results: The MOSFET and TLD dose values agreed within 3.0% and the MOSFET and TPS data within 0.5%. The convolution algorithm of the TPS, which is routinely applied in the clinic, overestimated the dose in the lung region. Using a superposition algorithm reduced the calculated lung dose by approximately 3%. The dose inhomogeneity, as predicted by the TPS, can be reduced using a simple intensity-modulated radiotherapy technique. Conclusions: The use of a TPS to calculate the dose distributions in individual patients during total body irradiation is strongly recommended. Using a TPS gives good insight of the over- and underdosage in a patient and the influence of patient positioning on dose homogeneity. MOSFETs are suitable for in vivo dosimetry purposes during total body irradiation, when using appropriate conversion factors. The MOSFET, TLD, and TPS results agreed within acceptable margins.

  7. A FUNCTIONAL AND ROENTGENOGRAPHIC PRELIMINARY COMPARATIVE STUDY USING METAL-BACKED AND ALL-POLYETHYLENE TIBIAL COMPONENTS IN TOTAL KNEE ARTHROPLASTY

    PubMed Central

    de Andrade, Marco Antônio Percope; dos Santos, Juliano Rodrigues; Gonzaga, Luiz Gustavo Alves; Silva, Guilherme Moreira Abreu e

    2015-01-01

    Objective: To describe and clinically and radiographically compare patients who underwent total knee arthroplasty (TKA) with all-polyethylene (ALP) and metal-backed (MTB) tibial implants. Methods: Patients who underwent TKA between January 1988 and December 2004 were grouped according to the type of implant received: all-polyethylene or metal-backed. Sixty patients came for evaluations, totaling 82 operated knees. Among these, 22 patients had undergone TKA only with ALP (12 unilateral and 10 bilateral cases), 33 patients only with MTB (26 unilateral and 7 bilateral cases) and five patients underwent TKA with ALP in one knee and MTB in the other. The knees were divided thus: group 1, 37 knees with ALP; and group 2, 45 knees with MTB. Results: There were no differences in clinical or functional evaluations between the groups. The mean radiolucency in the femur was 0.838 mm for the patients in group 1 and 0.356 mm for the patients in group 2 (p = 0.049). For the tibia, in the AP view, there was a mean value of 2.703 mm for group 1 and 0.733 mm for group 2 (p = 0.000). In the lateral view, the mean values for osteolysis was 0.405 mm for group 1 and 0.200 mm for group 2 (p = 0.074). Conclusions: There were no differences between the groups in the functional and clinical evaluations. However, greater radiolucency was observed in the arthroplasties with ALP, both in the femur in the lateral view and in the tibia in the AP view. Level of evidence IV – case series study. PMID:27022556

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

    SciTech Connect

    Hopkins, Philip F.

    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.

  9. Determination and chemometric evaluation of total aflatoxin, aflatoxin B1, ochratoxin A and heavy metals content in corn flours from Turkey.

    PubMed

    Algül, Işıl; Kara, Derya

    2014-08-15

    Concentrations of the total aflatoxin, aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, ochratoxin A, lead, cadmium, mercury, arsenic, copper, zinc and chromium in corn flour samples were determined. Eighteen corn flour samples that were obtained from different cities and villages in Turkey and 3 corn flour samples obtained from the UK. Determination of the different toxins was carried out using HPLC instrumentation after pre-separation using immunoaffinity columns that work through a mechanism of solid-phase extraction. An ICP-MS instrument was used for the heavy metal determinations. The results obtained from HPLC and ICP-MS analyses of the corn flour samples showed that these samples contain detectable levels of most of the analytes but the mercury was at undetectable levels. A very strong statistical relationship was observed between Cr and total Aflatoxin and Aflatoxin B1; whereas Ochratoxin A was related to Cu and Zn concentrations using correlation analyses and principal component analyses. PMID:24679753

  10. The Crucial Role of Divalent Metal Ions in the DNA-Acting Efficacy and Inhibition of the Transcription of Dimeric Chromomycin A3

    PubMed Central

    Hsu, Chun-Wei; Chuang, Show-Mei; Wu, Wen-Ling; Hou, Ming-Hon

    2012-01-01

    Chromomycin A3 (Chro) is capable of forming a stable dimeric complex via chelation with Ni(II), Fe(II) and Co(II). According to the circular dichroism study, the dimer conformations are significantly different among the Fe(II)-, Co(II)-, and Ni(II)-containing dimeric Chro complexes; however, the dimer conformations were preserved at high temperatures. Furthermore, we conducted a systematic study to determine the effects of these divalent metal ions on the DNA-acting efficacy of dimeric Chro, including its DNA-binding affinity, DNA stabilization capacity, DNA cleavage activity, and the inhibition of transcription both in vitro and within cells. Kinetic analyses using surface plasmon resonance (SPR) showed that NiII(Chro)2 exhibited the highest Ka with a value of 1.26×107 M−1, which is approximately 1.6- and 3.7-fold higher than the Ka values obtained for CoII(Chro)2 and FeII(Chro)2, respectively. The Tm and ΔG values for the DNA duplex increased after the addition of drug complexes in the following order: NiII(Chro)2>CoII(Chro)2>FeII(Chro)2. In the DNA integrity assays, the DNA cleavage rate of CoII(Chro)2 (1.2×10−3 s−1) is higher than those of FeII(Chro)2 and NiII(Chro)2, which were calculated to be 1×10−4 and 3.1×10−4 s−1, respectively. Consistent with the SPR and UV melting results, NiII(Chro)2 possesses the highest inhibitory effect on in vitro transcription and c-myc transcription within cells compared to CoII(Chro)2 and FeII(Chro)2. By comparing the cytotoxicity among CoII(Chro)2, FeII(Chro)2, and NiII(Chro)2 to several cancer cell lines, our studies concluded that NiII(Chro)2 displayed more potential antitumor activities than CoII(Chro)2 and FeII(Chro)2 did due to its higher DNA-acting efficacy. Changes to the divalent metal ions in the dimeric Chro complexes have been correlated with improved anticancer profiles. The availability of new metal derivatives of Chro may introduce new possibilities for exploiting the unique properties of this

  11. Synthesis-atomic structure-properties relationships in metallic nanoparticles by total scattering experiments and 3D computer simulations: case of Pt-Ru nanoalloy catalysts

    NASA Astrophysics Data System (ADS)

    Prasai, Binay; Ren, Yang; Shan, Shiyao; Zhao, Yinguang; Cronk, Hannah; Luo, Jin; Zhong, Chuan-Jian; Petkov, Valeri

    2015-04-01

    An approach to determining the 3D atomic structure of metallic nanoparticles (NPs) in fine detail and using the unique knowledge obtained for rationalizing their synthesis and properties targeted for optimization is described and exemplified on Pt-Ru alloy NPs of importance to the development of devices for clean energy conversion such as fuel cells. In particular, PtxRu100-x alloy NPs, where x = 31, 49 and 75, are synthesized by wet chemistry and activated catalytically by a post-synthesis treatment involving heating under controlled N2-H2 atmosphere. So-activated NPs are evaluated as catalysts for gas-phase CO oxidation and ethanol electro-oxidation reactions taking place in fuel cells. Both as-synthesized and activated NPs are characterized structurally by total scattering experiments involving high-energy synchrotron X-ray diffraction coupled to atomic pair distribution functions (PDFs) analysis. 3D structure models both for as-synthesized and activated NPs are built by molecular dynamics simulations based on the archetypal for current theoretical modelling Sutton-Chen method. Models are refined against the experimental PDF data by reverse Monte Carlo simulations and analysed in terms of prime structural characteristics such as metal-to-metal bond lengths, bond angles and first coordination numbers for Pt and Ru atoms. Analysis indicates that, though of a similar type, the atomic structure of as-synthesized and respective activated NPs differ in several details of importance to NP catalytic properties. Structural characteristics of activated NPs and data for their catalytic activity are compared side by side and strong evidence found that electronic effects, indicated by significant changes in Pt-Pt and Ru-Ru metal bond lengths at NP surface, and practically unrecognized so far atomic ensemble effects, indicated by distinct stacking of atomic layers near NP surface and prevalence of particular configurations of Pt and Ru atoms in these layers, contribute to the

  12. Analyses of heavy metals in sewage and sludge from treatment plants in the cities of Campinas and Jaguariúna, using synchrotron radiation total reflection X-rayfluorescence

    NASA Astrophysics Data System (ADS)

    Souza, L. C. F.; Canteras, F. B.; Moreira, S.

    2014-02-01

    A major consequence of accelerated urban and industrial development in the last decades is water pollution. In particular, metal contamination is a significant problem, causing serious changes to the environment and adversely affecting human health. The cities of Campinas and Jaguariúna are inserted in the Campinas Metropolitan Region (CMR), one of the most dynamic regions in the Brazilian economy, accounting for 2.7% of Gross National Product (GNP) and 7.83% of São Paulo State Product—or approximately $ 70.7 billion per year. Besides having a strong economy, the region also presents an infrastructure that provides the development of the entire metropolitan area. Therefore, to study the anthropogenic influences of the cities, the evaluation of the quality of raw and treated effluent and, the sludge generated in sewage treatment plants (STP), especially with regard to heavy metals was performed by Total Reflection X-Ray Fluorescence with Synchrotron Radiation technique. The results were compared with the allowed values established by Brazilian Legislation. For raw and treated effluents collected in Jaguariúna and Campinas city in the Stations of Treatment of Sewage (Camanducaia and Anhumas), Cr presented higher concentrations than the maximum allowed values established by CONAMA 357. However, it is necessary to do other studies to define the fraction of Cr+3 and Cr+6 to compare to the new legislation. The other elements were in agreement with established regulations. For sludge sampled in the same locations, the concentrations of Cr, Cu, Pb, Ni and Zn were compared with the CONAMA 375 and showed values smaller than the maximum allowed values, indicating the possibility to re-use the sludge.

  13. Adverse local tissue reaction (ALTR) associated with corrosion products in metal-on-metal and dual modular neck total hip replacements is associated with upregulation of interferon gamma-mediated chemokine signaling.

    PubMed

    Kolatat, Kritti; Perino, Giorgio; Wilner, Gabrielle; Kaplowitz, Elianna; Ricciardi, Benjamin F; Boettner, Friedrich; Westrich, Geoffrey H; Jerabek, Seth A; Goldring, Steven R; Purdue, P Edward

    2015-10-01

    Adverse local tissue reactions (ALTR) associated with tribocorrosion following total hip arthroplasty (THA) have become a significant clinical concern in recent years. In particular, implants featuring metal-on-metal bearing surfaces and modular femoral stems have been reported to result in elevated rates of ALTR. These tribocorrosion-related tissue reactions are characterized by marked necrosis and lymphocytic infiltration, which contrasts sharply with the macrophagic and foreign body giant cell inflammation associated with polyethylene wear particle induced peri-implant osteolysis. In this study, we characterize tribocorrosion-associated ALTR at a molecular level. Gene expression profiling of peri-implant tissue around failing implants identifies upregulation of numerous inflammatory mediators in ALTR, including several interferon gamma inducible factors, most notably the chemokines MIG/CXCL9 and IP-10/CXCL10. This expression profile is distinct from that associated with polyethylene wear induced osteolysis, which is characterized by induction of markers of alternative macrophage activation, such as chitotriosidase (CHIT-1). Importantly, MIG/CXCL9 and IP-10/CXCL10 are also elevated at the protein level in the synovial fluid and, albeit more moderately, the serum, of ALTR patients, raising the possibility that these factors may serve as circulating biomarkers for the early detection of ALTR in at-risk patients. PMID:25940887

  14. Total Hip Arthroplasty Using Modular Trabecular Metal Acetabular Components for Failed Treatment of Acetabular Fractures: A Mid-term Follow-up Study

    PubMed Central

    Huang, De-Yong; Zhang, Liang; Zhou, Yi-Xin; Zhang, Chun-Yu; Xu, Hui; Huang, Yong

    2016-01-01

    Background: Porous-coated cups have been widely used in acetabular reconstruction after failed treatment of acetabular fractures, and good results have been reported with the use of these cups; however, the durability and functionality of modular trabecular metal (TM) acetabular components in acetabular reconstruction after failed treatment of acetabular fractures remain unclear. This study aimed to examine the radiographic and clinical outcomes associated with the use of modular TM acetabular components for failed treatment of acetabular fractures to assess the durability and functionality of these components in acetabular reconstruction after failed treatment of acetabular fractures. Methods: A total of 41 patients (41 hips) underwent total hip arthroplasty (THA) using modular TM acetabular components for failed treatment of acetabular fractures at our hospital between January 2007 and December 2012. Among these patients, two were lost to follow-up. Therefore, 39 patients (39 hips) were finally included in this study. The Harris hip score before and after the surgery, satisfaction level of the patients, and radiographic results were assessed. Results: The mean Harris hip score increased from 34 (range, 8–52) before surgery to 91 (range, 22–100) at the latest follow-up examination (P < 0.001). The results were excellent for 28 hips, good for six, fair for three, and poor for two. Among the 39 patients, 25 (64%) and 10 (26%) were very satisfied and somewhat satisfied, respectively. All cups were found to be fully incorporated, and no evidence of cup migration or periacetabular osteolysis was noted. Conclusions: Despite the technically demanding nature of the procedure, THA using modular TM acetabular components showed good durability and functionality and may be an effective reconstruction option for failed treatment of acetabular fractures. PMID:27064033

  15. Dietary exposure to metals and other elements in the 2006 UK Total Diet Study and some trends over the last 30 years.

    PubMed

    Rose, M; Baxter, M; Brereton, N; Baskaran, C

    2010-10-01

    Concentrations of 24 elements including metals in the 2006 UK Total Diet Study (TDS) were measured and dietary exposures estimated. Composite samples for the 20 TDS food groups (bread, fish, fruit, etc.) were collected from 24 UK towns and analysed for their levels of aluminium, antimony, arsenic, barium, bismuth, cadmium, chromium, copper, germanium, indium, lead, manganese, mercury, molybdenum, nickel, palladium, platinum, rhodium, ruthenium, selenium, strontium, thallium, tin, and zinc. Concentrations of each of the elements in the food groups were lower than or similar to those reported in the previous TDS survey, conducted in 2000, with the exception of aluminium, barium, and manganese. Dietary exposures to the 24 elements were estimated for UK consumers and compared with previous estimates made over the last 30 years in order to examine any trends in exposure to these elements in the typical UK diet. Population exposures to the elements have generally declined over time, and exposures to most of these elements remain at low levels. The independent UK Government scientific Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) commented on the estimated dietary exposures, taking into account their previous evaluations (in 2003 and 2008), and identified no major concerns for the health of consumers, but did advise that there was a need for more information on aluminium and barium, and also commented that dietary exposure to inorganic arsenic and to lead should continue to be reduced. PMID:20628929

  16. Metal mining facilities. Section 313 of the Emergency Planning and Community Right-to-Know Act, toxic chemical release inventory: Industry guidance

    SciTech Connect

    1999-01-01

    This document is intended to assist establishments and facilities designated by the Standard Industrial Classification (SIC) Major Group 10 (except SIC codes 1011, 1081, and 1094) in making compliance determinations under the EPCRA Section 313 reporting requirements and preparing Form R(s) or the Form A certification statement(s) as required. Chapter 1 serves as an introduction to TRI reporting and provides a brief background on the Emergency Planning and Community Right-to-Know Act and information on where to obtain additional compliance assistance. Chapter 2 begins with how to determine if a facility must report. Chapter 2 concludes with a discussion on how to address trade secrets in reporting and the kinds of records that should be kept to support reporting. Chapter 3 discusses how to calculate the activity thresholds (manufacture, process, and otherwise use) for the EPCRA Section 313 chemicals. Chapter 3 concludes with a discussion of how to determine whether EPCRA Section 313 chemicals exceed a reporting threshold, including focused discussions on issues specific to metal mining facilities. Chapter 4 discusses how to calculate the release and other waste management amounts for those EPCRA Section 313 chemicals for which a report must be prepared. This chapter provides a step-by-step approach designed to minimize the risk of overlooking an activity involving an EPCRA Section 313 chemical and any potential sources or types of releases and other waste management activities that a facility may conduct.

  17. A Copper-Based Metal-Organic Framework Acts as a Bifunctional Catalyst for the Homocoupling of Arylboronic Acids and Epoxidation of Olefins.

    PubMed

    Parshamoni, Srinivasulu; Telangae, Jyothi; Sanda, Suresh; Konar, Sanjit

    2016-02-18

    A copper(I)-based metal-organic framework ({[Cu2 Br2 (pypz)]n ⋅nH2 O} (Cu-Br-MOF) [pypz=bis[3,5-dimethyl-4-(4'-pyridyl)pyrazol-1-yl] methane] has been synthesized by using an elongated and flexible bridging ligand. The structure analysis reveals that each pypz ligand acts as a tritopic ligand connected to two Cu2 Br2 dimeric units, forming a one-dimensional zig-zag chain, and these chains further connected by a Cu2 Br2 unit, give a two-dimensional framework on the bc-plane. In the Cu2 Br2 dimeric unit, the copper ions are four coordinated, thereby possessing a tetrahedral geometry; this proves to be an excellent heterogeneous catalyst for the aerobic homocoupling of arylboronic acids under mild reaction conditions. This method requires only 3 mol % of catalyst and it does not require any base or oxidant-compared to other conventional (Cu, Pd, Fe, and Au) catalysts-for the transformation of arylboronic acids in very good yields (98 %). The shape and size selectivity of the catalyst in the homocoupling was investigated. The use of the catalyst was further extended to the epoxidation of olefins. Moreover, the catalyst can be easily separated by simple filtration and reused efficiently up to 5 cycles without major loss of reactivity. PMID:26629650

  18. Comparison of the risk of revision in cementless total hip arthroplasty with ceramic-on-ceramic and metal-on-polyethylene bearings

    PubMed Central

    Varnum, Claus; Pedersen, Alma B; Kjærsgaard-Andersen, Per; Overgaard, Søren

    2015-01-01

    Background and purpose Ceramic-on-ceramic (CoC) bearings were introduced in total hip arthroplasty (THA) to reduce problems related to polyethylene wear. We compared the 9-year revision risk for cementless CoC THA and for cementless metal-on-polyethylene (MoP) THA. Patients and methods In this prospective, population-based study from the Danish Hip Arthroplasty Registry, we identified all the primary cementless THAs that had been performed from 2002 through 2009 (n = 25,656). Of these, 1,773 THAs with CoC bearings and 9,323 THAs with MoP bearings were included in the study. To estimate the relative risk (RR) of revision, we used regression with the pseudo-value approach and treated death as a competing risk. Results 444 revisions were identified: 4.0% for CoC THA (71 of 1,773) and 4.0% for MoP THA (373 of 9,323). No statistically significant difference in the risk of revision for any reason was found for CoC and MoP bearings after 9 years of follow-up (adjusted RR = 1.3, 95% CI: 0.72–2.4). Revision rates due to component failure were 0.5% (n = 8) for CoC bearings and 0.1% (n = 6) for MoP bearings (p < 0.001). 6 patients with CoC bearings (0.34%) underwent revision due to ceramic fracture. Interpretation When compared to the “standard” MoP bearings, CoC THA had a 33% higher (though not statistically significantly higher) risk of revision for any reason at 9 years. PMID:25637339

  19. Determination of metallic contaminants on Ge wafers using direct- and droplet sandwich etch-total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Hellin, D.; Bearda, T.; Zhao, C.; Raskin, G.; Mertens, P. W.; De Gendt, S.; Heyns, M. M.; Vinckier, C.

    2003-12-01

    An analysis methodology for the metallic contamination control of Ge wafer substrates has been developed and evaluated for six elements (K, Ca, Cr, Fe, Ni and Zn). Detection limits (DL) of Direct-total reflection X-ray fluorescence spectrometry (D-TXRF) analysis on Ge wafers have been determined and found to be at the E10 at/cm 2 level. The values have been found to be a factor between 1 and 3 higher than on Si wafers, exclusively caused by differences in the background intensity. Additionally, a preconcentration procedure based on the Droplet sandwich etch (DSE) method has been developed. This method relies on the transfer of the surface and subsurface contaminants from the wafer to the liquid phase by wet chemical etching. Application of the DSE method on reference Ge wafers followed by analysis of the etch liquid by TXRF resulted in recovery rates (RR) of 40%. In an optimization study, it was found that the main DSE method parameters had limited influence on the RR. However, a detection efficiency study clearly demonstrated an underestimation by the TXRF analysis. An independent analysis for Ca, Cr, Fe and Zn by GF-AAS resulted in RR varying at approximately 100%. By internal standardization with the element La for the TXRF analysis, recovery rates could be increased to the 60% level. This underestimation by TXRF may find an origin in a matrix effect caused by the Ge etch products. By application of the developed DSE-TXRF method, DL at the E9 at/cm 2 level could be realized, with values, which are at least one order of magnitude lower compared to the DL of D-TXRF on Ge wafers.

  20. Levels of direct-acting mutagens, total N-nitroso compounds in nitrosated fermented fish products, consumed in a high-risk area for gastric cancer in southern China.

    PubMed

    Chen, C S; Pignatelli, B; Malaveille, C; Bouvier, G; Shuker, D; Hautefeuille, A; Zhang, R F; Bartsch, H

    1992-02-01

    A high gastric cancer mortality in Fujian province (Peoples Republic of China) has been associated with the consumption of certain salted fermented fish products such as fish sauce (FS). We have investigated the levels and nature of N-nitroso compounds (NOC) and genotoxins present, before and after nitrosation, in 49 FS samples collected from villages in this high-risk area, pooled into six samples. The concentrations of total NOC before nitrosation ranged from 0.2 to 16 mumoles/l, and after nitrosation at pH 2 and pH 7, they rose by up to 4800- and 100-fold, respectively. In nitrosated samples, 40-50% of total NOC was not extractable into organic solvents; volatile N nitrosamines accounted for 1-2% and N-nitrosamino acids for 8-16% of total NOC. None of the FS samples exhibited genotoxic activity, but after nitrosation all were weakly active in the SOS chromotest. The highest SOS-inducing potency was observed with nitrosated ethyl acetate extracts of most samples. The formation of methylating agents was measured by incubation of nitrosated FS with DNA and subsequent analysis of 7-methylguanine adduct. 2 of the 6 nitrosated FS samples caused a slight increase in DNA methylation. 1 pooled home-made FS sample (the only one tested) contained tumour promoter-like substances, as measured by expression of certain EBV genes in Raji cells. HPLC fractionation of ethyl acetate extracts of FS samples allowed identification of three UV-absorbing peaks that, upon nitrosation, produced direct-acting genotoxins. This genotoxicity was partly ascribed to the formation of nitrite-derived arene diazonium cations that were characterized by a coupling reaction with N-ethyl-1-naphthylamine and thin-layer chromatography. PMID:1370720

  1. Total protein

    MedlinePlus

    The total protein test measures the total amount of two classes of proteins found in the fluid portion of your ... nutritional problems, kidney disease or liver disease . If total protein is abnormal, you will need to have more ...

  2. Total protein

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/003483.htm Total protein To use the sharing features on this page, please enable JavaScript. The total protein test measures the total amount of two classes ...

  3. Structural evolution across the insulator-metal transition in oxygen-deficient BaTiO3-δ studied using neutron total scattering and Rietveld analysis

    SciTech Connect

    Jeong, I.-K.; Lee, Seunghun; Jeong, Se-Young; Won, C. J.; Hur, N.; Llobet, A.

    2011-08-29

    Oxygen-deficient BaTiO3-δ exhibits an insulator-metal transition with increasing δ. We performed neutron total scattering measurements to study structural evolution across an insulator-metal transition in BaTiO3-δ. Despite its significant impact on resistivity, slight oxygen reduction (δ=0.09) caused only a small disturbance on the local doublet splitting of Ti-O bond. This finding implies that local polarization is well preserved under marginal electric conduction. In the highly oxygen-deficient metallic state (δ=0.25), however, doublet splitting of the Ti-O bond became smeared. The smearing of the local Ti-O doublet is complemented with long-range structural analysis and demonstrates that the metallic conduction in the highly oxygen-reduced BaTiO3-δ is due to the appearance of nonferroelectric cubic lattice.

  4. Study rationale and protocol: prospective randomized comparison of metal ion concentrations in the patient's plasma after implantation of coated and uncoated total knee prostheses

    PubMed Central

    Lützner, Jörg; Dinnebier, Gerd; Hartmann, Albrecht; Günther, Klaus-Peter; Kirschner, Stephan

    2009-01-01

    Background Any metal placed in a biological environment undergoes corrosion. Thus, with their large metallic surfaces, TKA implants are particularly prone to corrosion with subsequent release of metal ions into the human body which may cause local and systemic toxic effects and hypersensitivity reactions, and increase cancer risk. To address this problem, a new 7-layer zirconium coating developed especially for cobalt-chrome orthopaedic implants was tested biomechanically and found to lower metal ion release. The purpose of the proposed clinical trial is to compare the metal ion concentration in patients' plasma before and after implantation of a coated or uncoated TKA implant. Methods/Design In this randomised controlled trial, 120 patients undergoing primary TKA will be recruited at the Department of Orthopaedic Surgery of the University Hospital in Dresden, Germany, and randomised to either the coated or uncoated prosthesis. Outcome assessments will be conducted preoperatively and at 3 months, 12 months and 5 years postoperatively. The primary clinical endpoint will be the chromium ion concentration in the patient's plasma after 1 and 5 years. Secondary outcomes include cobalt, molybdenum and nickel ion concentrations after 1 and 5 years, allergy testing for hypersensitivity against one of these metals, the Knee Society Score to assess clinical and physical function of the knee joint, the self-assessment Oxford Score and the Short Form 36 quality of live questionnaire. Discussion The metal ion concentration in the patient's plasma has been shown to increase after TKA, its eventual adverse effects being widely debated. In the light of this discussion, ways to reduce metal ion release from orthopaedic implants should be studied in detail. The results of this investigation may lead to a new method to achieve this goal. Trials register Clinicaltrials registry NCT00862511 PMID:19828019

  5. Alumina-on-alumina ceramic versus metal-on-highly cross-linked polyethylene bearings in total hip arthroplasty: a comparative study.

    PubMed

    Bascarevic, Zoran; Vukasinovic, Zoran; Slavkovic, Nemanja; Dulic, Borislav; Trajkovic, Goran; Bascarevic, Violeta; Timotijevic, Sladjan

    2010-12-01

    The aim of the study was to evaluate the reliability and durability of alumina-on-alumina ceramic in comparison to metal-on-highly cross-linked polyethylene (CoCr/HXLPE) bearing couples. This prospective randomised study involved 150 patients (157 hips). All patients (mean age: 54.7 years) obtained an identical fibre metal midcoat femoral stem and fibre metal-coated acetabular shell. In 78 patients (82 hips) we used alumina, while in 72 patients (75 hips) metal-polyethylene bearing couples were used. During a mean 50.4-month follow-up period (51 ± 8 alumina and 50 ± 8.9 metal-polyethylene) no statistically significant changes in clinical and radiographic parameters were noted between the two groups. There was no ceramic breakage and no need for revision surgery due to the ceramic liner. The alumina bearing couples proved to be as reliable as CoCr/HXLPE. PMID:19882338

  6. Adhesive strength of total knee endoprostheses to bone cement - analysis of metallic and ceramic femoral components under worst-case conditions.

    PubMed

    Bergschmidt, Philipp; Dammer, Rebecca; Zietz, Carmen; Finze, Susanne; Mittelmeier, Wolfram; Bader, Rainer

    2016-06-01

    Evaluation of the adhesive strength of femoral components to the bone cement is a relevant parameter for predicting implant safety. In the present experimental study, three types of cemented femoral components (metallic, ceramic and silica/silane-layered ceramic) of the bicondylar Multigen Plus knee system, implanted on composite femora were analysed. A pull-off test with the femoral components was performed after different load and several cementing conditions (four groups and n=3 components of each metallic, ceramic and silica/silane-layered ceramic in each group). Pull-off forces were comparable for the metallic and the silica/silane-layered ceramic femoral components (mean 4769 N and 4298 N) under standard test condition, whereas uncoated ceramic femoral components showed reduced pull-off forces (mean 2322 N). Loading under worst-case conditions led to decreased adhesive strength by loosening of the interface implant and bone cement using uncoated metallic and ceramic femoral components, respectively. Silica/silane-coated ceramic components were stably fixed even under worst-case conditions. Loading under high flexion angles can induce interfacial tensile stress, which could promote early implant loosening. In conclusion, a silica/silane-coating layer on the femoral component increased their adhesive strength to bone cement. Thicker cement mantles (>2 mm) reduce adhesive strength of the femoral component and can increase the risk of cement break-off. PMID:25781660

  7. Evaluation of sample preparation methods for the detection of total metal content using inductively coupled plasma optical emission spectrometry (ICP-OES) in wastewater and sludge

    NASA Astrophysics Data System (ADS)

    Dimpe, K. M.; Ngila, J. C.; Mabuba, N.; Nomngongo, P. N.

    Heavy metal contamination exists in aqueous wastes and sludge of many industrial discharges and domestic wastewater, among other sources. Determination of metals in the wastewater and sludge requires sample pre-treatment prior to analysis because of certain challenges such as the complexity of the physical state of the sample, which may lead to wrong readings in the measurement. This is particularly the case with low analyte concentration to be detected by the instrument. The purpose of this work was to assess and validate the different sample preparation methods namely, hot plate and microwave-assisted digestion procedures for extraction of metal ions in wastewater and sludge samples prior to their inductively coupled plasma optical emission spectrometric (ICP-OES) determination. For the extraction of As, Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn, three acid mixtures, that is, HNO3/H2O2, HNO3/HClO4/H2O2 and aqua regia + H2O2, were evaluated. Influent wastewater spiked with the SRM (CWW-TM-B) was used for the optimization of acid mixtures affecting the extraction procedure. After sample digestion, the filtration capabilities of cellulose-acetate filter paper and the acrodisc syringe filter with the pore size of 0.45 μm were compared. In terms of performance, acrodisc syringe filter in terms of the improved recoveries obtained, was found to be the best filtration method compared to the filter paper. Based on the analytical results obtained, microwave-assisted digestion (MAD) using aqua regia + H2O2 mixture was found to be the most suitable method for extraction of heavy metals and major elements in all the sample matrices. Therefore, MAD using aqua regia + H2O2 mixture was used for further investigations. The precision of the developed MAD method expressed in terms of relative standard deviations (% RSD) for different metals was found to be <5%. The limits of detection (LOD) and limits of quantification (LOQ) ranged from 0.12% to 2.18 μg L-1 and 0.61% to 3.43 μg L-1

  8. Fate of metals in coastal sediments of a Mediterranean flood-dominated system: An approach based on total and labile fractions

    NASA Astrophysics Data System (ADS)

    Roussiez, Vincent; Ludwig, Wolfgang; Radakovitch, Olivier; Probst, Jean-Luc; Monaco, André; Charrière, Bruno; Buscail, Roselyne

    2011-05-01

    The dynamics of sediment-bound metals (Cs, Cu, Ni, Pb, Ti and Zn) were studied off the Têt River (western Gulf of Lion), a typical Mediterranean coastal river punctuated by short and violent flash-floods. Spatial and temporal sampling strategies were combined to elucidate the fate of these elements in response to both the riverine sediment input and the offshore transport of these sediments through hydrodynamics. Our results show the temporal entrapment of riverborne particles and associated metals, consecutively to a major flood event, in the nearshore sedimentary unit called prodelta. Here, deposition and resuspension mechanisms define a sedimentological cycle that could be followed completely in this study. In terms of speciation between reactive (labile) and residual fractions along the fluvio-deltaic continuum, our results show that Cu, Pb and Zn are the most labile (potentially mobile) metals in the river, in accordance with their contributions from anthropogenic sources. But in the marine surficial sediments, two main behaviours can be discriminated when compared to the riverine suspended particulate matter. While Pb and Zn depict rather a constant labile fraction, Cu is characterized by decreasing levels (up to 50% difference). In terms of environmental impact, these contrasting trends have direct repercussions for the contaminant dispersal in the coastal area. Whereas Pb and Zn conserve their enhanced levels because of their stronger affinity with fine sediments, Cu is marked by the entire loss of its anthropogenic component that is progressively transferred to the dissolved phase, likely mediated by organic ligands. We ascribe these behaviours to different post-depositional partition mechanisms with respect to oxidation of the particulate organic phase at the bottom sediment/water interface. Also, analysis of one sediment core from the prodelta indicates that these early diagenetic processes govern the chemical forms of land-derived contaminants

  9. Total-dose response of silicon-on-insulator (soi) metal-oxide- semiconductor field-effect transistor's (mosfet's). Master's thesis

    SciTech Connect

    Biwer, M.C.

    1988-06-01

    Total-dose response of both NMOS and PMOS FET's fabricated on SIMOX and ZMR substrates was studied. Two types of back-channel leakage currents were identified for the SIMOX devices. A back channel leakage due to MOSFET action uses the substrate bias as the gate bias. The other component is due to soft reverse characteristics of the body-drain junction. The back-channel leakage due to MOSFET action varies with the substrate bias and thus varies with irradiation due to threshold-voltage shift. The soft reverse current is a function of drain-body voltage and hence varies with substrate bias and irradiation. The threshold-voltage, I-V characteristics, and subthreshold currents of both front and back channels as a function of total dose were obtained.

  10. Hybrid alumina total hip arthroplasty using a press-fit metal-backed socket in patients younger than 55 years. A six- to 11-year evaluation.

    PubMed

    Bizot, P; Hannouche, D; Nizard, R; Witvoet, J; Sedel, L

    2004-03-01

    Between 1990 and 1992, we implanted 71 hybrid alumina-on-alumina hip arthroplasties in 62 consecutive patients under the age of 55 years, with a mean age of 46 years at surgery. There were 56 primary and 15 secondary procedures. The prostheses involved a cemented titanium alloy stem, a 32 mm alumina head, and a press-fit metal-backed socket with an alumina insert. Three patients (four hips) died from unrelated causes. Four hips had revision surgery for either deep infection, unexplained persistent pain, fracture of the alumina head, or aseptic loosening of the socket. The nine-year survival rate was 93.7% with revision for any cause as the end-point and 98.4% with revision for aseptic loosening as the end-point. The outcome in the surviving patients (50 patients, 57 hips) with a minimum five-year follow-up (mean eight years) was excellent in 47 hips (82.5%), very good in eight (14%), good in one and fair in one. A thin, partial, lucent line, mainly in zone III was present in 38% of the sockets and one socket had a complete lucency less than 1 mm thick. One stem had isolated femoral osteolysis. There was no detectable component migration nor acetabular osteolysis. This hybrid arthroplasty gave satisfactory medium-term results in active patients. The press-fit metal-backed socket appeared to have reliable fixation in alumina-on-alumina hip arthroplasty. The excellent results using cemented fixation of the stem may be related to the low production of wear debris. PMID:15046431

  11. Accumulations of total metal in dominant shrimp species (Palaemon adspersus, Palaemon serratus, Parapenaeus longirostris) and bottom surface sediments obtained from the Northern Inner Shelf of the Sea of Marmara.

    PubMed

    Kurun, A; Balkis, H; Balkis, N

    2007-12-01

    The aim of this study is to determine the total metal (aluminum, copper, manganese, nickel, lead, zinc, cadmium, iron, mercury) contents of dominant shrimp species and sediments present at 1-50 m depths of the Northern Inner Shelf of the Sea of Marmara. Shrimp and sediment samples were collected from four regions (Büyükçekmece, Silivri, Tekirdağ, Sarköy) and from different depths (1, 5, 10, 20, 30, 50 m) at each region in September and November of 2003. Three shrimp species [Palaemon adspersus (Rathke, 1937), Palaemon serratus (Pennant, 1777), Parapenaeus longirostris (H. Lucas, 1846)] were identified to be dominant as a result of the examination on the obtained samples. Heavy metal contents of these three species were determined and the results were compared with the acceptable treshold values of the Seafood Standards and also with available literatures. The Cu contents were found to be higher than the treshold limits in all samples except P. longirostris from Silivri, also the Cd contents in all samples except P. adspersus from Büyükçekmece, the Zn contents only in P. adspersus and P. longirostris from Tekirdağ, and the Pb contents in all species from all regions. These high values are the indicator of industrial pollution. There is not any data in the Seafood Standards about Mn, Ni, Fe and Al contents in shrimp species. The values of these metal contents were given in the present study. The examination of total metal distributions in bottom surface sediment samples in the Northern Inner Shelf of the Sea of Marmara showed that the determined values were higher than the shale average at some depths of examined stations. PMID:17406997

  12. Shorter, rough trunnion surfaces are associated with higher taper wear rates than longer, smooth trunnion surfaces in a contemporary large head metal-on-metal total hip arthroplasty system.

    PubMed

    Brock, Timothy M; Sidaginamale, Raghavendra; Rushton, Steven; Nargol, Antoni V F; Bowsher, John G; Savisaar, Christina; Joyce, Tom J; Deehan, David J; Lord, James K; Langton, David J

    2015-12-01

    Taper wear at the head-neck junction is a possible cause of early failure in large head metal-on-metal (LH-MoM) hip replacements. We hypothesized that: (i) taper wear may be more pronounced in certain product designs; and (ii) an increased abductor moment arm may be protective. The tapers of 104 explanted LH-MoM hip replacements revised for adverse reaction to metal debris (ARMD) from a single manufacturer were analyzed for linear and volumetric wear using a co-ordinate measuring machine. The mated stem was a shorter 12/14, threaded trunnion (n=72) or a longer, smooth 11/13 trunnion (n=32). The abductor moment arm was calculated from pre-revision radiographs. Independent predictors of linear and volumetric wear included taper angle, stem type, and the horizontal moment arm. Tapers mated with the threaded 12/14 trunnion had significantly higher rates of volumetric wear (0.402 mm3/yr vs. 0.123 mm3/yr [t=-2.145, p=0.035]). There was a trend to larger abductor moment arms being protective (p=0.055). Design variation appears to play an important role in taper-trunnion junction failure. We recommend that surgeons bear these findings in mind when considering the use of a short, threaded trunnion with a cobalt-chromium head. PMID:26135357

  13. Enhanced Total Ionizing Dose Hardness of Deep Sub-Micron Partially Depleted Silicon-on-Insulator n-Type Metal-Oxide-Semiconductor Field Effect Transistors by Applying Larger Back-Gate Voltage Stress

    NASA Astrophysics Data System (ADS)

    Zheng, Qi-Wen; Cui, Jiang-Wei; Yu, Xue-Feng; Guo, Qi; Zhou, Hang; Ren, Di-Yuan

    2014-12-01

    The larger back-gate voltage stress is applied on 130 nm partially depleted silicon-on-insulator n-type metal-oxide-semiconductor field-effect transistors isolated by shallow trench isolation. The experimental results show that the back-gate sub-threshold hump of the device is eliminated by stress. This observed behavior is caused by the high electric field in the oxide near the bottom corner of the silicon island. The total ionizing dose hardness of devices with pre back-gate stress is enhanced by the interface states induced by stress.

  14. Total Synthesis of K777: Successful Application of Transition-Metal-Catalyzed Alkyne Hydrothiolation toward the Modular Synthesis of a Potent Cysteine Protease Inhibitor.

    PubMed

    Kiemele, Erica R; Wathier, Matthew; Bichler, Paul; Love, Jennifer A

    2016-02-01

    We report the total synthesis of K777 and a series of analogues via alkyne hydrothiolation catalyzed by Wilkinson's complex (ClRh(PPh3)3). The alkyne hydrothiolation reactions proceeded with excellent regio- and diastereoselectivity to generate the desired E-linear vinyl sulfides in high yield. The use of Ellman's auxiliary generates the requisite propargyl amines in excellent enantiomeric excess (ee) and obviates the use of L-homophenylalanine, an expensive unnatural amino acid. The vinyl sulfone derivatives exhibit a large difference in rate toward Michael addition. Kinetic data are consistent with rate-limiting nucleophilic attack to generate the carbanion intermediate. PMID:26811991

  15. Retrospective cohort study of the performance of the Pinnacle metal on metal (MoM) total hip replacement: a single-centre investigation in combination with the findings of a national retrieval centre

    PubMed Central

    Langton, David John; Sidaginamale, Raghavendra Prasad; Avery, Peter; Waller, Sue; Tank, Ghanshyabhai; Lord, James; Joyce, Thomas; Cooke, Nick; Logishetty, Raj; Nargol, Antoni Viraf Francis

    2016-01-01

    Objectives To determine risk factors for revision in patients implanted with a commonly used metal on metal (MoM) hip replacement. Design Retrospective cohort study in combination with a prospective national retrieval study (Northern Retrieval Registry (NRR)). Setting Combined orthopaedic unit in combination with the NRR. Participants All patients implanted with a DePuy Pinnacle MoM hip prostheses by the 2 senior authors were invited to attend for a review which included clinical examination, blood metal ion measurements, radiographs and targeted imaging. Explanted components underwent wear analysis using validated methodology and these results were compared with those obtained from the NRR. Results 489 MoM Pinnacle hips were implanted into 434 patients (243 females and 191 males). Of these, 352 patients attended the MoM recall clinics. 64 patients had died during the study period. For the purposes of survival analysis, non-attendees were assumed to have well-functioning prostheses. The mean follow-up of the cohort as a whole was 89 months. 71 hips were revised. Prosthetic survival for the whole cohort was 83.6% (79.9–87.3) at 9 years. The majority of explanted devices exhibited signs of taper junction failure. Risk factors for revision were bilateral MoM prostheses, smaller Pinnacle liners, and implantation in 2006 and later years. A significant number of devices were found to be manufactured out of their specifications. This was confirmed with analysis of the wider data set from the NRR. Conclusions This device was found to have an unacceptably high revision rate. Bilateral prostheses, those implanted into female patients and devices implanted in later years were found to be at greater risk. A significant number of explanted components were found to be manufactured with bearing diameters outside of the manufacturer's stated tolerances. Our findings highlight the clinical importance of hitherto unrecognised variations in device production. PMID:27130159

  16. Balancing Acts

    MedlinePlus

    ... Current Issue Past Issues Special Section: Focus on Communication Balancing Acts Past Issues / Fall 2008 Table of ... from the National Institute on Deafness and Other Communication Disorders (NIDCD). It involves simulated trips down the ...

  17. Acting Atoms.

    ERIC Educational Resources Information Center

    Farin, Susan Archie

    1997-01-01

    Describes a fun game in which students act as electrons, protons, and neutrons. This activity is designed to help students develop a concrete understanding of the abstract concept of atomic structure. (DKM)

  18. ACT Test

    MedlinePlus

    ... this page helpful? Also known as: ACT; Activated Coagulation Time Formal name: Activated Clotting Time Related tests: ... in the blood called platelets and proteins called coagulation factors are activated in a sequence of steps ...

  19. Determination of total antioxidant capacity of humic acids using CUPRAC, Folin-Ciocalteu, noble metal nanoparticle- and solid-liquid extraction-based methods.

    PubMed

    Karadirek, Şeyda; Kanmaz, Nergis; Balta, Zeynep; Demirçivi, Pelin; Üzer, Ayşem; Hızal, Jülide; Apak, Reşat

    2016-06-01

    Total antioxidant capacity (TAC) of humic acid (HA) samples was determined using CUPRAC (CUPric Reducing Antioxidant Capacity), FC (Folin-Ciocalteu), QUENCHER-CUPRAC, QUENCHER-FC, Ag-NP (Silver nanoparticle)‒ and Au-NP (Gold nanoparticle)‒based methods. Conventional FC and modified FC (MFC) methods were applied to solid samples. Because of decreased solubility of Folin-Ciocalteu's phenol reagent in organic solvents, solvent effect on TAC measurement was investigated using QUENCHER-CUPRAC assay by using ethanol:distilled water and dimethyl sulfoxide:distilled water with varying ratios. To see the combined effect of solubilization (leaching) and TAC measurement of humic acids simultaneously, QUENCHER experiments were performed at 25°C and 50°C; QUENCHER-CUPRAC and QUENCHER-FC methods agreed well and had similar precision in F-statistics. Although the Gibbs free energy change (ΔG°) of the oxidation of HA dihydroxy phenols with the test reagents were negative, the ΔG° was positive only for the reaction of CUPRAC reagent with isolated monohydric phenols, showing CUPRAC selectivity toward polyphenolic antioxidants. This is the first work on the antioxidant capacity measurement of HA having a sparingly soluble matrix where enhanced solubilization of bound phenolics is achieved with coupled oxidation by TAC reagents. PMID:27130098

  20. Development of new in situ observation system for dynamic study of lubricant molecules on metal friction surfaces by two-dimensional fast-imaging Fourier-transform infrared-attenuated total reflection spectrometer.

    PubMed

    Sasaki, Keiji; Inayoshi, Naruhiko; Tashiro, Kohji

    2008-12-01

    To observe the time-dependent two-dimensional (2D) images of spatial distribution of chemically/physically modified lubricant molecules on the metal surface during friction motion, a new in situ technique has been developed by combining the 2D fast-imaging Fourier-transform infrared-attenuated total reflection spectrometer with the temperature-controlled friction equipment containing lubricant agent. Using this new instrument, the time-dependent changes in lubricant molecules, for example, cis-trans isomerization, stress-induced molecular deformation, etc., can be detected successfully. The characteristic features of this instrument have been demonstrated in a detailed and concrete manner by demonstrating the experimental data measured for oleic acid and tricresyl phosphate. PMID:19123564

  1. Green approach for ultratrace determination of divalent metal ions and arsenic species using total-reflection X-ray fluorescence spectrometry and mercapto-modified graphene oxide nanosheets as a novel adsorbent.

    PubMed

    Sitko, Rafal; Janik, Paulina; Zawisza, Beata; Talik, Ewa; Margui, Eva; Queralt, Ignasi

    2015-03-17

    A new method based on dispersive microsolid phase extraction (DMSPE) and total-reflection X-ray fluorescence spectrometry (TXRF) is proposed for multielemental ultratrace determination of heavy metal ions and arsenic species. In the developed methodology, the crucial issue is a novel adsorbent synthesized by grafting 3-mercaptopropyl trimethoxysilane on a graphene oxide (GO) surface. Mercapto-modified graphene oxide (GO-SH) can be applied in quantitative adsorption of cobalt, nickel, copper, cadmium, and lead ions. Moreover, GO-SH demonstrates selectivity toward arsenite in the presence of arsenate. Due to such features of GO-SH nanosheets as wrinkled structure and excellent dispersibility in water, GO-SH seems to be ideal for fast and simple preconcentration and determination of heavy metal ions using methodology based on DMSPE and TXRF measurement. The suspension of GO-SH was injected into an analyzed water sample; after filtration, the GO-SH nanosheets with adsorbed metal ions were redispersed in a small volume of internal standard solution and deposited onto a quartz reflector. The high enrichment factor of 150 allows obtaining detection limits of 0.11, 0.078, 0.079, 0.064, 0.054, and 0.083 ng mL(-1) for Co(II), Ni(II), Cu(II), As(III), Cd(II), and Pb(II), respectively. Such low detection limits can be obtained using a benchtop TXRF system without cooling media and gas consumption. The method is suitable for the analysis of water, including high salinity samples difficult to analyze using other spectroscopy techniques. Moreover, GO-SH can be applied to the arsenic speciation due to its selectivity toward arsenite. PMID:25707847

  2. Liquid metal cold trap

    DOEpatents

    Hundal, Rolv

    1976-01-01

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

  3. A frictional study of total hip joint replacements

    NASA Astrophysics Data System (ADS)

    Scholes, S. C.; Unsworth, A.; Goldsmith, A. A. J.

    2000-12-01

    Polymeric wear debris produced by articulation of the femoral head against the ultra-high-molecular-weight polyethylene socket of a total hip replacement has been implicated as the main cause of osteolysis and subsequent failure of these implants. Potential solutions to this problem are to employ hard bearing surface combinations such as metal-on-metal or ceramic-on-ceramic prostheses. The aim of this study was to investigate the difference in lubrication modes and friction of a range of material combinations using synthetic and biological fluids as the lubricants. The experimental results were compared with theoretical predictions of film thicknesses and lubrication modes. A strong correlation was observed between experiment and theory when employing carboxy methyl cellulose (CMC) fluids as the lubricant. Under these conditions the ceramic-on-ceramic joints showed full fluid film lubrication while the metal-on-metal, metal-on-plastic, diamond-like carbon-coated stainless steel (DLC)-on-plastic and ceramic-on-plastic prostheses operated under a mixed lubrication regime. With bovine serum as the lubricant in the all ceramic joints, however, the full fluid film lubrication was inhibited due to adsorbed proteins. In the metal-on-metal joints this adsorbed protein layer acted to reduce the friction while in the ceramic coupling the friction was increased. The use of bovine serum as the lubricant also significantly increased the friction in both the metal-on-plastic and ceramic-on-plastic joints. The friction produced by the DLC-on-plastic joints depended on the quality of the coating. Those joints with a less consistent coating and therefore a higher surface roughness gave significantly higher friction than the smoother, more consistently coated heads.

  4. Metal Preferences and Metallation*

    PubMed Central

    Foster, Andrew W.; Osman, Deenah; Robinson, Nigel J.

    2014-01-01

    The metal binding preferences of most metalloproteins do not match their metal requirements. Thus, metallation of an estimated 30% of metalloenzymes is aided by metal delivery systems, with ∼25% acquiring preassembled metal cofactors. The remaining ∼70% are presumed to compete for metals from buffered metal pools. Metallation is further aided by maintaining the relative concentrations of these pools as an inverse function of the stabilities of the respective metal complexes. For example, magnesium enzymes always prefer to bind zinc, and these metals dominate the metalloenzymes without metal delivery systems. Therefore, the buffered concentration of zinc is held at least a million-fold below magnesium inside most cells. PMID:25160626

  5. Act resilient.

    PubMed

    Joseph, Genie; Bice-Stephens, Wynona

    2014-01-01

    Attendees have reported changing from being fearful to serene, from listless to energized, from disengaged to connected, and becoming markedly less anxious in a few weeks. Anecdotally, self-reported stress levels have been reduced by over 50% after just one class. Attendees learn not to be afraid of their feelings by working with emotions in a playful manner. When a person can act angry, but separate himself from his personal story, the emotional energy exists in a separate form that is not attached to specific events, and can be more easily dealt with and neutralized. Attendees are taught to "take out the emotional trash" through expressive comedy. They become less intimated by their own emotional intensity and triggers as they learn how even metaphorical buckets of anger, shame, guilt and hurt can be emotionally emptied. The added benefit is that this is accomplished without the disclosure of personal information of the requirement to reexperience past pain which can trigger its own cascade of stress. PMID:24706248

  6. Taper junction failure in large-diameter metal-on-metal bearings

    PubMed Central

    Langton, D. J.; Sidaginamale, R.; Lord, J. K.; Nargol, A. V. F.; Joyce, T. J.

    2012-01-01

    Objectives An ongoing prospective study to investigate failing metal-on-metal hip prostheses was commenced at our centre in 2008. We report on the results of the analysis of the first consecutive 126 failed mated total hip prostheses from a single manufacturer. Methods Analysis was carried out using highly accurate coordinate measuring to calculate volumetric and linear rates of the articular bearing surfaces and also the surfaces of the taper junctions. The relationship between taper wear rates and a number of variables, including bearing diameter and orientation of the acetabular component, was investigated. Results The measured rates of wear and distribution of material loss from the taper surfaces appeared to show that the primary factor leading to taper failure is the increased lever arm acting on this junction in contemporary large-diameter metal-on-metal hip replacements. Conclusions Our analysis suggests that varus stems, laterally engaging taper systems and larger head diameters all contribute to taper failure. PMID:23610672

  7. Metal Theft Prevention Act of 2013

    THOMAS, 113th Congress

    Rep. Paulsen, Erik [R-MN-3

    2013-02-27

    04/08/2013 Referred to the Subcommittee on Crime, Terrorism, Homeland Security, And Investigations. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  8. National Activity Based Total Accountability Act of 2011

    THOMAS, 112th Congress

    Rep. Posey, Bill [R-FL-15

    2011-04-05

    04/08/2011 Referred to the Subcommittee on Technology, Information Policy, Intergovernmental Relations and Procurement Reform . (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  9. Bonding Elastomers To Metal Substrates

    NASA Technical Reports Server (NTRS)

    Dickerson, George E.; Kelley, Henry L.

    1990-01-01

    Improved, economical method for bonding elastomers to metals prevents failures caused by debonding. In new technique, vulcanization and curing occur simultaneously in specially designed mold that acts as form for desired shape of elastomer and as container that positions and supports metal parts. Increases interface adhesion between metal, adhesive, and elastomer.

  10. Total Energy CMR Production

    SciTech Connect

    Friedrich, S; Kolagani, R M

    2008-08-11

    The following outlines the optimized pulsed laser deposition (PLD) procedure used to prepare Nd{sub 0.67}Sr{sub 0.33}MnO{sub 3} (NSMO) temperature sensors at Towson University (Prof. Rajeswari Kolagani) for the LCLS XTOD Total Energy Monitor. The samples have a sharp metal/insulator transition at T {approx} 200 K and are optimized for operation at T {approx} 180 K, where their sensitivity is the highest. These samples are epitaxial multilayer structures of Si/YSZ/CeO/NSMO, where these abbreviations are defined in table 1. In this heterostructure, YSZ serves as a buffer layer to prevent deleterious chemical reactions, and also serves to de-oxygenate the amorphous SiO{sub 2} surface layer to generate a crystalline template for epitaxy. CeO and BTO serve as template layers to minimize the effects of thermal and lattice mismatch strains, respectively. More details on the buffer and template layer scheme are included in the attached manuscript accepted for publication in Sensor Letters (G. Yong et al., 2008).

  11. Metal-ligand cooperation.

    PubMed

    Khusnutdinova, Julia R; Milstein, David

    2015-10-12

    Metal-ligand cooperation (MLC) has become an important concept in catalysis by transition metal complexes both in synthetic and biological systems. MLC implies that both the metal and the ligand are directly involved in bond activation processes, by contrast to "classical" transition metal catalysis where the ligand (e.g. phosphine) acts as a spectator, while all key transformations occur at the metal center. In this Review, we will discuss examples of MLC in which 1) both the metal and the ligand are chemically modified during bond activation and 2) bond activation results in immediate changes in the 1st coordination sphere involving the cooperating ligand, even if the reactive center at the ligand is not directly bound to the metal (e.g. via tautomerization). The role of MLC in enabling effective catalysis as well as in catalyst deactivation reactions will be discussed. PMID:26436516

  12. Biomaterials in total joint replacement.

    PubMed

    Katti, Kalpana S

    2004-12-10

    The current state of materials systems used in total hip replacement is presented in this paper. An overview of the various material systems used in total hip replacement reported in literature is presented in this paper. Metals, polymers, ceramics and composites are used in the design of the different components of hip replacement implants. The merits and demerits of these material systems are evaluated in the context of mechanical properties most suitable for total joint replacement such as a hip implant. Current research on advanced polymeric nanocomposites and biomimetic composites as novel materials systems for bone replacement is also discussed. This paper examines the current research in the materials science and the critical issues and challenges in these materials systems that require further research before application in biomedical industry. PMID:15556342

  13. TETE: Total Education in the Total Environment.

    ERIC Educational Resources Information Center

    Eblen, William R.

    The Hudson River Museum's Environmental Arts and Science Division has published this booklet describing their model educational program, "TETE: Total Education in the Total Environment," a multidisciplinary approach to environmental education utilizing existing curricula. For conducting the program model communities strategically located along the…

  14. Virus templated metallic nanoparticles.

    PubMed

    Aljabali, Alaa A A; Barclay, J Elaine; Lomonossoff, George P; Evans, David J

    2010-12-01

    Plant viruses are considered as nanobuilding blocks that can be used as synthons or templates for novel materials. Cowpea mosaic virus (CPMV) particles have been shown to template the fabrication of metallic nanoparticles by an electroless deposition metallization process. Palladium ions were electrostatically bound to the virus capsid and, when reduced, acted as nucleation sites for the subsequent metal deposition from solution. The method, although simple, produced highly monodisperse metallic nanoparticles with a diameter of ca. ≤35 nm. CPMV-templated particles were prepared with cobalt, nickel, iron, platinum, cobalt-platinum and nickel-iron. PMID:20877898

  15. 20 CFR 410.422 - Determining total disability: General criteria.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Determining total disability: General... HEALTH AND SAFETY ACT OF 1969, TITLE IV-BLACK LUNG BENEFITS (1969- ) Total Disability or Death Due to Pneumoconiosis § 410.422 Determining total disability: General criteria. (a) A determination of total...

  16. 20 CFR 410.422 - Determining total disability: General criteria.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Determining total disability: General... HEALTH AND SAFETY ACT OF 1969, TITLE IV-BLACK LUNG BENEFITS (1969- ) Total Disability or Death Due to Pneumoconiosis § 410.422 Determining total disability: General criteria. (a) A determination of total...

  17. Virus templated metallic nanoparticles

    NASA Astrophysics Data System (ADS)

    Aljabali, Alaa A. A.; Barclay, J. Elaine; Lomonossoff, George P.; Evans, David J.

    2010-12-01

    Plant viruses are considered as nanobuilding blocks that can be used as synthons or templates for novel materials. Cowpea mosaic virus (CPMV) particles have been shown to template the fabrication of metallic nanoparticles by an electroless deposition metallization process. Palladium ions were electrostatically bound to the virus capsid and, when reduced, acted as nucleation sites for the subsequent metal deposition from solution. The method, although simple, produced highly monodisperse metallic nanoparticles with a diameter of ca. <=35 nm. CPMV-templated particles were prepared with cobalt, nickel, iron, platinum, cobalt-platinum and nickel-iron.Plant viruses are considered as nanobuilding blocks that can be used as synthons or templates for novel materials. Cowpea mosaic virus (CPMV) particles have been shown to template the fabrication of metallic nanoparticles by an electroless deposition metallization process. Palladium ions were electrostatically bound to the virus capsid and, when reduced, acted as nucleation sites for the subsequent metal deposition from solution. The method, although simple, produced highly monodisperse metallic nanoparticles with a diameter of ca. <=35 nm. CPMV-templated particles were prepared with cobalt, nickel, iron, platinum, cobalt-platinum and nickel-iron. Electronic supplementary information (ESI) available: Additional experimental detail, agarose gel electrophoresis results, energy dispersive X-ray spectra, ζ-potential measurements, dynamic light scattering data, nanoparticle tracking analysis and an atomic force microscopy image of Ni-CPMV. See DOI: 10.1039/c0nr00525h

  18. Letter to the Editor Re: Andrew Turner, Emily R. Kearl, Kevin R. Solman Lead and other toxic metals in playground paints from South West England Science of the Total Environment 544 (2016) 460-466.

    PubMed

    Gottesfeld, Perry; Jacobs, David E

    2016-08-15

    Turner's paper emphasizes "oral bioaccessibility" instead of focusing solely on total lead content. There is no evidence that solubility testing for lead levels in paint correlates with absorption or blood lead levels in exposed children. There are many considerations in determining exposure hazards to paint that are not evaluated in assessing solubility. Although we strongly support the conclusions and recommendations of the study, we are concerned that by reporting "oral bioaccessibility" others will focus on solubility in developing regulatory standards for lead levels in paint or in conducting exposure assessments. Standards for lead in paint should continue to be based on total lead content, not "oral bioaccessibility." PMID:27260620

  19. Technique for joining metal tubing

    NASA Technical Reports Server (NTRS)

    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.

  20. ACTS data center

    NASA Technical Reports Server (NTRS)

    Syed, Ali; Vogel, Wolfhard J.

    1993-01-01

    Viewgraphs on ACTS Data Center status report are included. Topics covered include: ACTS Data Center Functions; data flow overview; PPD flow; RAW data flow; data compression; PPD distribution; RAW Data Archival; PPD Audit; and data analysis.

  1. ACTS data center

    NASA Astrophysics Data System (ADS)

    Syed, Ali; Vogel, Wolfhard J.

    1993-08-01

    Viewgraphs on ACTS Data Center status report are included. Topics covered include: ACTS Data Center Functions; data flow overview; PPD flow; RAW data flow; data compression; PPD distribution; RAW Data Archival; PPD Audit; and data analysis.

  2. Recovery Act Milestones

    SciTech Connect

    Rogers, Matt

    2009-01-01

    Every 100 days, the Department of Energy is held accountable for a progress report on the American Recovery and Reinvestment Act. Update at 200 days, hosted by Matt Rogers, Senior Advisor to Secretary Steven Chu for Recovery Act Implementation.

  3. Recovery Act Milestones

    ScienceCinema

    Rogers, Matt

    2013-05-29

    Every 100 days, the Department of Energy is held accountable for a progress report on the American Recovery and Reinvestment Act. Update at 200 days, hosted by Matt Rogers, Senior Advisor to Secretary Steven Chu for Recovery Act Implementation.

  4. Leaching Properties of Naturally Occurring Heavy Metals from Soils

    NASA Astrophysics Data System (ADS)

    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

  5. Forgetting ACT UP

    ERIC Educational Resources Information Center

    Juhasz, Alexandra

    2012-01-01

    When ACT UP is remembered as the pinnacle of postmodern activism, other forms and forums of activism that were taking place during that time--practices that were linked, related, just modern, in dialogue or even opposition to ACT UP's "confrontational activism"--are forgotten. In its time, ACT UP was embedded in New York City, and a larger world,…

  6. Silicon metal-semiconductor-metal photodetector

    DOEpatents

    Brueck, Steven R. J.; Myers, David R.; Sharma, Ashwani K.

    1995-01-01

    Silicon MSM photodiodes sensitive to radiation in the visible to near infrared spectral range are produced by altering the absorption characteristics of crystalline Si by ion implantation. The implantation produces a defected region below the surface of the silicon with the highest concentration of defects at its base which acts to reduce the contribution of charge carriers formed below the defected layer. The charge carriers generated by the radiation in the upper regions of the defected layer are very quickly collected between biased Schottky barrier electrodes which form a metal-semiconductor-metal structure for the photodiode.

  7. Silicon metal-semiconductor-metal photodetector

    DOEpatents

    Brueck, Steven R. J.; Myers, David R.; Sharma, Ashwani K.

    1997-01-01

    Silicon MSM photodiodes sensitive to radiation in the visible to near infrared spectral range are produced by altering the absorption characteristics of crystalline Si by ion implantation. The implantation produces a defected region below the surface of the silicon with the highest concentration of defects at its base which acts to reduce the contribution of charge carriers formed below the defected layer. The charge carriers generated by the radiation in the upper regions of the defected layer are very quickly collected between biased Schottky barrier electrodes which form a metal-semiconductor-metal structure for the photodiode.

  8. Trace metal determination by total-reflection X-ray fluorescence (TXRF) for the differentiation between pure fuel oil (bunker oil) and waste oil (sludge) in maritime shipping legal cases

    NASA Astrophysics Data System (ADS)

    Schirmacher, Martina; Freimann, Peter; Schmidt, Diether; Dahlmann, Gerhard

    1993-02-01

    Using a simple sample preparation technique, the concentrations of Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn and Pb in several bunker and sludge oils have been measured simultaneously by total-reflection X-ray fluorescence analysis (TXRF) in the mg/kg range. As a result, five elements are suitable in distinguishing between both types of oil: Ca, V, Fe, Ni and Zn. This differentiation can be used in cases where shipping vessel captains or chiefs attempt to conceal illegal waste oil discharge at sea by wrongly declaring bunker oil as sludge.

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

    PubMed

    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. PMID:25106048

  10. No superiority of cemented metal-on-metal vs metal-on-polyethylene THA at 5-year follow-up.

    PubMed

    Zijlstra, Wierd P; Cheung, John; Sietsma, Maurits S; van Raay, Jos Jam; Deutman, Robert

    2009-07-01

    A randomized controlled trial was performed to compare the cemented Stanmore metal-on-metal (Biomet, Warsaw, Indiana) total hip arthroplasty (THA; 102 hips) to the cemented Stanmore metal-on-polyethylene (Biomet) THA (98 hips). The primary outcome was clinical performance. Radiological performance, serum cobalt analysis, and prosthetic survival were secondary outcome measures. At a mean follow-up of 5.6 years, 5 patients were lost to follow-up, 18 died, and 4 were revised (3 metal-on- metal, 1 metal-on-polyethylene). Harris Hip Scores improved from 48 to 90 in the metal-on-metal patients (P<.001) and from 46 to 87 in the metal-on-polyethylene patients (P<.001). Oxford Hip Scores changed from 40 to 19 in the metal-on-metal group (P<.001) and from 40 to 18 in the metal-on-polyethylene group (P<.001). For both Harris and Oxford Hip Scores, there was no significant difference between the 2 groups. Five-year survival with revision for any reason was 97% (95% CI 93%-100%) in the metal-on-metal group and 99% (95% CI 97%-100%) in the metal-on-polyethylene group. All revisions were indicated for aseptic loosening (metal-on-metal: 3 cup revisions; metal-on-polyethylene: 1 total revision). At 5-year follow-up, cemented metal-on-metal THA showed no clinical superiority over metal-on-polyethylene THA. PMID:19634856

  11. Parallel Total Energy

    2004-10-21

    This is a total energy electronic structure code using Local Density Approximation (LDA) of the density funtional theory. It uses the plane wave as the wave function basis set. It can sue both the norm conserving pseudopotentials and the ultra soft pseudopotentials. It can relax the atomic positions according to the total energy. It is a parallel code using MP1.

  12. Total Quality Leadership

    NASA Technical Reports Server (NTRS)

    1991-01-01

    More than 750 NASA, government, contractor, and academic representatives attended the Seventh Annual NASA/Contractors Conference on Quality and Productivity. The panel presentations and Keynote speeches revolving around the theme of total quality leadership provided a solid base of understanding of the importance, benefits, and principles of total quality management (TQM). The presentations from the conference are summarized.

  13. Act II of the Sunshine Act.

    PubMed

    Pham-Kanter, Genevieve

    2014-11-01

    To coincide with the introduction in the United States of the Sunshine Act, Genevieve Pham-Kanter discusses what we need to look for to fight hidden bias and deliberate or unconscious corruption. Please see later in the article for the Editors' Summary. PMID:25369363

  14. The Total Irradiance Monitors

    NASA Astrophysics Data System (ADS)

    Kopp, Greg

    2015-08-01

    The first Total Irradiance Monitor (TIM) launched on NASA’s Solar Radiation and Climate Experiment in 2003 and quickly proved to be the most accurate and stable instrument on orbit for measuring the total solar irradiance (TSI). The TIM’s design improvements over the older classical radiometers helped its selection on many subsequent missions, including NASA’s Glory, NOAA’s TSI Calibration Transfer Experiment, and the series of NASA’s Total and Spectral Solar Irradiance Sensor instruments currently underway. I will summarize the status of and differences between each of the TIMs currently on-orbit or in production.

  15. Total parenteral nutrition - infants

    MedlinePlus

    Total parenteral nutrition (TPN) is a method of feeding that bypasses the gastrointestinal tract. Fluids are given into a vein to ... babies. It can provide a better level of nutrition than regular intravenous (IV) feedings, which provide only ...

  16. Total parenteral nutrition

    MedlinePlus

    Total parenteral nutrition (TPN) will help you or your child get nutrition from a special formula through a vein in the ... you can also eat and drink while getting nutrition from TPN. Your nurse will teach you how ...

  17. Tourniquetless Total Knee Arthroplasty

    MedlinePlus Videos and Cool Tools

    Tourniquetless Total Knee Arthroplasty You must have Javascript enabled in your web browser. View Program Transcript Click Here to view the OR-Live, Inc. Privacy Policy and Legal Notice © 2010 OR- ...

  18. Total Water Management - slides

    EPA Science Inventory

    Total Water Management (TWM) examines urban water systems in an interconnected manner. It encompasses reducing water demands, increasing water recycling and reuse, creating water supply assets from stormwater management, matching water quality to end-use needs, and achieving envi...

  19. Wavelength-dispersive total-reflection X-ray fluorescence with an efficient Johansson spectrometer and an undulator X-ray source: detection of 10-16 g-level trace metals.

    PubMed

    Sakurai, Kenji; Eba, Hiromi; Inoue, Katsuaki; Yagi, Naoto

    2002-09-01

    The present paper reports significant enhancement of the detection power for total-reflection X-ray fluorescence (TXRF). The employment of an efficient wavelength-dispersive spectrometer rather than a conventional Si(Li) detector, as well as the use of a quasi-monochromatic undulator X-ray source, completely changed the quality of X-ray florescence spectra. The energy resolution is 20 times better, which effectively contributes to reducing the low-energy tail of the scattering background and to separating neighboring X-ray florescence peaks. Another advantage is its capability with respect to high-counting-rate measurements, which ensure the detection of weak signals from trace materials. The absolute and relative detection limit for nickel are 3.1 x 10(-16) g and 3.1 ppt (pg/g) for a 0.1-microL droplet of pure water, respectively, which is nearly 50 times better than the current best data achieved by conventional energy-dispersive TXRF using a Si(Li) detector system. PMID:12236366

  20. Total lymphoid irradiation

    SciTech Connect

    Sutherland, D.E.; Ferguson, R.M.; Simmons, R.L.; Kim, T.H.; Slavin, S.; Najarian, J.S.

    1983-05-01

    Total lymphoid irradiation by itself can produce sufficient immunosuppression to prolong the survival of a variety of organ allografts in experimental animals. The degree of prolongation is dose-dependent and is limited by the toxicity that occurs with higher doses. Total lymphoid irradiation is more effective before transplantation than after, but when used after transplantation can be combined with pharmacologic immunosuppression to achieve a positive effect. In some animal models, total lymphoid irradiation induces an environment in which fully allogeneic bone marrow will engraft and induce permanent chimerism in the recipients who are then tolerant to organ allografts from the donor strain. If total lymphoid irradiation is ever to have clinical applicability on a large scale, it would seem that it would have to be under circumstances in which tolerance can be induced. However, in some animal models graft-versus-host disease occurs following bone marrow transplantation, and methods to obviate its occurrence probably will be needed if this approach is to be applied clinically. In recent years, patient and graft survival rates in renal allograft recipients treated with conventional immunosuppression have improved considerably, and thus the impetus to utilize total lymphoid irradiation for its immunosuppressive effect alone is less compelling. The future of total lymphoid irradiation probably lies in devising protocols in which maintenance immunosuppression can be eliminated, or nearly eliminated, altogether. Such protocols are effective in rodents. Whether they can be applied to clinical transplantation remains to be seen.

  1. Alkali metal for ultraviolet band-pass filter

    NASA Technical Reports Server (NTRS)

    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.

  2. ACT and College Success

    ERIC Educational Resources Information Center

    Bleyaert, Barbara

    2010-01-01

    What is the relationship between ACT scores and success in college? For decades, admissions policies in colleges and universities across the country have required applicants to submit scores from a college entrance exam, most typically the ACT (American College Testing) or SAT (Scholastic Aptitude Test). This requirement suggests that high school…

  3. Metal aminoboranes

    DOEpatents

    Burrell, Anthony K.; Davis, Benjamin J.; Thorn, David L.; Gordon, John C.; Baker, R. Thomas; Semelsberger, Troy Allen; Tumas, William; Diyabalanage, Himashinie Vichalya Kaviraj; Shrestha, Roshan P.

    2010-05-11

    Metal aminoboranes of the formula M(NH.sub.2BH.sub.3).sub.n have been synthesized. Metal aminoboranes are hydrogen storage materials. Metal aminoboranes are also precursors for synthesizing other metal aminoboranes. Metal aminoboranes can be dehydrogenated to form hydrogen and a reaction product. The reaction product can react with hydrogen to form a hydrogen storage material. Metal aminoboranes can be included in a kit.

  4. ``Electric growth`` of metal overlayers on semiconductor substrates

    SciTech Connect

    Zhang, Z.; Cho, J.H. |; Niu, Q.; Shih, C.K.; Suo, Z.

    1998-02-01

    In this article, the authors present the main results from their recent studies of metal overlayer growth on semiconductor substrates. They show that a variety of novel phenomena can exist in such systems, resulting from several competing interactions. The confined motion of the conduction electrons within the metal overlayer can mediate a surprisingly long-range repulsive force between the metal-semiconductor interface and the growth front, acting to stabilize the overlayer. Electron transfer from the overlayer to the substrate leads to an attractive force between the two interfaces, acting to destabilize the overlayer. Interface-induced Friedel oscillations in electron density can further impose an oscillatory modulation onto the two previous interactions. These three competing factors, of all electronic nature, can make a flat metal overlayer critically, marginally, or magically stable, or totally unstable against roughening. The authors further show that, for many systems, these electronic effects can easily win over the effect of stress. First-principles studies of a few representative systems support the main features of the present electronic growth concept.

  5. Total Value of Phosphorus Recovery.

    PubMed

    Mayer, Brooke K; Baker, Lawrence A; Boyer, Treavor H; Drechsel, Pay; Gifford, Mac; Hanjra, Munir A; Parameswaran, Prathap; Stoltzfus, Jared; Westerhoff, Paul; Rittmann, Bruce E

    2016-07-01

    Phosphorus (P) is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (e.g., due to runoff or wastewater discharges), P is also a primary cause of eutrophication. To reconcile the simultaneous shortage and overabundance of P, lost P flows must be recovered and reused, alongside improvements in P-use efficiency. While this motivation is increasingly being recognized, little P recovery is practiced today, as recovered P generally cannot compete with the relatively low cost of mined P. Therefore, P is often captured to prevent its release into the environment without beneficial recovery and reuse. However, additional incentives for P recovery emerge when accounting for the total value of P recovery. This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovering P. This approach accounts for P products, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water. Additionally, P recovery provides valuable services to society and the environment by protecting and improving environmental quality, enhancing efficiency of waste treatment facilities, and improving food security and social equity. The needs to make P recovery a reality are also discussed, including business models, bottlenecks, and policy and education strategies. PMID:27214029

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

    PubMed

    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. PMID:26028168

  7. Total Energy Monitor

    SciTech Connect

    Friedrich, S

    2008-08-11

    The total energy monitor (TE) is a thermal sensor that determines the total energy of each FEL pulse based on the temperature rise induced in a silicon wafer upon absorption of the FEL. The TE provides a destructive measurement of the FEL pulse energy in real-time on a pulse-by-pulse basis. As a thermal detector, the TE is expected to suffer least from ultra-fast non-linear effects and to be easy to calibrate. It will therefore primarily be used to cross-calibrate other detectors such as the Gas Detector or the Direct Imager during LCLS commissioning. This document describes the design of the TE and summarizes the considerations and calculations that have led to it. This document summarizes the physics behind the operation of the Total Energy Monitor at LCLS and derives associated engineering specifications.

  8. Total colonoscopy in children.

    PubMed Central

    Williams, C. B.; Laage, N. J.; Campbell, C. A.; Douglas, J. R.; Walker-Smith, J. A.; Booth, I. W.; Harries, J. T.

    1982-01-01

    One hundred and twenty-three total colonoscopies were performed on 115 children with ages ranging from 3 months to 16 years. The major indications were suspected inflammatory bowel disease and unexplained rectal bleeding. Ninety-seven per cent of all procedures were carried out with sedation only. Adult colonoscopes were used in most of the patients but in babies and small children paediatric instruments were preferable. Total colonoscopy was possible in all patients with a patent colon. The terminal ileum was examined in 63 patients. Endoscopic snare polypectomy was successfully carried out in 8 children and multiple haemangiomas were electrocoagulated in one. Total colonoscopy in this paediatric series proved to be at least as easy, rapid, well-tolerated, and safe as in adults. In selected patients as single colonoscopy can give an accurate diagnosis with biopsy proof and sometimes the opportunity for definitive treatment. PMID:7065694

  9. Total Synthesis of (+)-Acutiphycin

    PubMed Central

    Moslin, Ryan M.; Jamison, Timothy F.

    2011-01-01

    Synthetic studies toward the total synthesis of (+)-acutiphycin (1) resulted in the discovery of additive-free, highly regioselective nickel-catalyzed reductive coupling reactions of aldehydes and 1,6-enynes and the construction of an advanced intermediate in studies directed toward the synthesis of 1. Ultimately, though not employing the nickel-catalyzed reaction, a highly convergent total synthesis of (+)-acutiphycin featuring an intermolecular SmI2-mediated Reformatsky coupling reaction and macrolactonization initiated by a retro-ene reaction of an alkoxyalkyne was achieved. The resulting synthesis was 18 steps in the longest linear sequence from either methyl acetoacetate or isobutyraldehyde. PMID:17985925

  10. Total Technology Immersion

    ERIC Educational Resources Information Center

    Vaughn, Sandy

    2010-01-01

    Total technology immersion doesn't happen overnight, but with vision and determination, transformation can take hold and start to grow. Floydada Independent School District (FISD), winner of the 2010 Sylvia Charp Award for District Innovation in Technology, is a great example of what a district can achieve when starting with a modest tech…

  11. Total synthesis of jiadifenolide.

    PubMed

    Paterson, Ian; Xuan, Mengyang; Dalby, Stephen M

    2014-07-01

    As a potent neurotrophic agent, the sesquiterpenoid jiadifenolide represents a valuable small-molecule lead for the potential therapeutic treatment of neurodegenerative diseases. A stereocontrolled total synthesis of this densely functionalized natural product is reported, central to which is an adventurous samarium-mediated cyclization reaction to establish the tricyclic core and the adjacent C5 and C6 quaternary stereocenters. PMID:24861364

  12. Total absorption Cherenkov spectrometers

    NASA Astrophysics Data System (ADS)

    Malinovski, E. I.

    2015-05-01

    A short review of 50 years of work done with Cherenkov detectors in laboratories at the Lebedev Physical Institute is presented. The report considers some issues concerning the use of Cherenkov total absorption counters based on lead glass and heavy crystals in accelerator experiments.

  13. Total Water Management

    EPA Science Inventory

    This project will investigate total water management (TWM) as a way of improving water resource management and reducing waste streams. This project will also improve management of potable water, wastewater and wet-weather flow through combined management, reuse and recycling wil...

  14. Total Synthesis of (-)-Cardiopetaline.

    PubMed

    Nishiyama, Yoshitake; Yokoshima, Satoshi; Fukuyama, Tohru

    2016-05-20

    The total synthesis of (-)-cardiopetaline, an aconitine-type natural product, has been accomplished. Our synthesis involved a Wagner-Meerwein rearrangement of a sulfonyloxirane that enabled, in a single step, the construction of the bicyclo[3.2.1] system in the aconitine skeleton and effective introduction of oxygen functional groups at the appropriate positions. PMID:27166640

  15. CSF total protein

    MedlinePlus

    CSF total protein is a test to determine the amount of protein in your spinal fluid, also called cerebrospinal fluid (CSF). ... The normal protein range varies from lab to lab, but is typically about 15 to 60 mg/dL. Note: mg/dL = ...

  16. "Total Deposition (TDEP) Maps"

    EPA Science Inventory

    The presentation provides an update on the use of a hybrid methodology that relies on measured values from national monitoring networks and modeled values from CMAQ to produce of maps of total deposition for use in critical loads and other ecological assessments. Additionally, c...

  17. Total Water Management - Report

    EPA Science Inventory

    There is a growing need for urban water managers to take a more holistic view of their water resource systems as population growth, urbanization, and current operations put different stresses on the environment and urban infrastructure. Total Water Management (TWM) is an approac...

  18. Estuarine Total Ecosystem Metabolism

    EPA Science Inventory

    Total ecosystem metabolism (TEM), both as discrete measurements and as a theoretical concept, has an important history in ecosystem ecology, particularly in estuaries. Some of the earliest ecological studies were developed to determine how energy flowed through an ecosystem and w...

  19. Total Synthesis of Jiadifenolide**

    PubMed Central

    Paterson, Ian; Xuan, Mengyang; Dalby, Stephen M

    2014-01-01

    As a potent neurotrophic agent, the sesquiterpenoid jiadifenolide represents a valuable small-molecule lead for the potential therapeutic treatment of neurodegenerative diseases. A stereocontrolled total synthesis of this densely functionalized natural product is reported, central to which is an adventurous samarium-mediated cyclization reaction to establish the tricyclic core and the adjacent C5 and C6 quaternary stereocenters. PMID:24861364

  20. TOTAL DIET STUDY

    EPA Science Inventory

    The Total Diet Study (TDS), sometimes called the Market Basket Study, is an ongoing FDA program that determines levels of various pesticide residues, contaminants, and nutrients in foods, for the purpose of estimating intakes of these substances in representative diets of specifi...

  1. Total Precipitable Water

    SciTech Connect

    2012-01-01

    The simulation was performed on 64K cores of Intrepid, running at 0.25 simulated-years-per-day and taking 25 million core-hours. This is the first simulation using both the CAM5 physics and the highly scalable spectral element dynamical core. The animation of Total Precipitable Water clearly shows hurricanes developing in the Atlantic and Pacific.

  2. Total Quality Management Seminar.

    ERIC Educational Resources Information Center

    Massachusetts Career Development Inst., Springfield.

    This booklet is one of six texts from a workplace literacy curriculum designed to assist learners in facing the increased demands of the workplace. The booklet contains seven sections that cover the following topics: (1) meaning of total quality management (TQM); (2) the customer; (3) the organization's culture; (4) comparison of management…

  3. Total Quality Management Simplified.

    ERIC Educational Resources Information Center

    Arias, Pam

    1995-01-01

    Maintains that Total Quality Management (TQM) is one method that helps to monitor and improve the quality of child care. Lists four steps for a child-care center to design and implement its own TQM program. Suggests that quality assurance in child-care settings is an ongoing process, and that TQM programs help in providing consistent, high-quality…

  4. Guidance for Total Development.

    ERIC Educational Resources Information Center

    Van Hoose, William H.

    Elementary guidance, deriving much of its content from the developmental phenomena of middle childhood, is viewed as the maximization of human potentiality in the total range of the population. Included in the list of elementary school guidance objectives are (1) aiding academic development, (2) helping children develop health self-concepts, (3)…

  5. Variation of metals in bed sediments of Qaraaoun Reservoir, Lebanon.

    PubMed

    Korfali, Samira Ibrahim; Jurdi, Mey; Davies, Brian E

    2006-04-01

    The Qaraaoun Reservoir (impoundment of the River Litani) is the only artificial surface water body in the country, Lebanon. Earlier study on the water quality of the Qaraaoun Reservoir identified three water quality zoning with a central distinct zone suitable for multipurpose water usage. The objective of this study was to extend the earlier work by considering the total metal content of reservoir bed sediments and hence to evaluate factors that control metal deposition or capture. Water samples were collected from 15 sampling sites and sediment samples were simultaneously collected from 9 sites. Water parameters analyzed were pH, Eh, DO and temperature. Sediment samples were dried and sieved and sediment < 75 microm was retained for analysis. Sediments were subjected to a stepwise heating process with aqua regia to extract the metals, and their content in sediments determined by ICP-MS. The sediment data revealed higher metal contents where the river entered the reservoir which matched higher concentrations of water parameters at the influx site. Regression analysis of total metals in sediments with distance from the river Litani influx point to the dam revealed a log trend for Fe, Cr and Ni, whereas, the concentrations of Cu, Zn, Cd, Pb were better described by a polynomial regression. Three sediment zones were identified: entrance, oxidation (central) and reducing (near dam) zones. Sediment contents of Zn, Cu and Pb correlated with organic content, whereas sediment Cr and Ni were associated with iron. It was concluded that sediments act as a sink for metals and the deposition of metals is primarily related to sediment organic content and the level of dissolved oxygen in water. PMID:16649137

  6. Assertive Community Treatment (ACT)

    MedlinePlus

    ... community treatment? Assertive community treatment (ACT) is a model of psychiatric care that can be very effective ... it the most. Similar to the “treatment team” model of an inpatient psychiatric unit, which includes nurses, ...

  7. The ACTS propagation program

    NASA Technical Reports Server (NTRS)

    Chakraborty, Dayamoy; Davarian, Faramaz

    1991-01-01

    The purpose of the Advanced Communications Technology Satellite (ACTS) is to demonstrate the feasibility of the Ka-band (20 and 30 GHz) spectrum for satellite communications, as well as to help maintain U.S. leadership in satellite communications. ACTS incorporates such innovative schemes as time division multiple access (TDMA), microwave and baseband switching, onboard regeneration, and adaptive application of coding during rain-fade conditions. The success or failure of the ACTS experiment will depend on how accurately the rain-fade statistics and fade dynamics can be predicted in order to derive an appropriate algorithm that will combat weather vagaries, specifically for links with small terminals, such as very small aperture terminals (VSAT's) where the power margin is a premium. This article describes the planning process and hardware development program that will comply with the recommendations of the ACTS propagation study groups.

  8. ACTS mobile SATCOM experiments

    NASA Technical Reports Server (NTRS)

    Abbe, Brian S.; Frye, Robert E.; Jedrey, Thomas C.

    1993-01-01

    Over the last decade, the demand for reliable mobile satellite communications (satcom) for voice, data, and video applications has increased dramatically. As consumer demand grows, the current spectrum allocation at L-band could become saturated. For this reason, NASA and the Jet Propulsion Laboratory are developing the Advanced Communications Technology Satellites (ACTS) mobile terminal (AMT) and are evaluating the feasibility of K/Ka-band (20/30 GHz) mobile satcom to meet these growing needs. U.S. industry and government, acting as co-partners, will evaluate K/Ka-band mobile satcom and develop new technologies by conducting a series of applications-oriented experiments. The ACTS and the AMT testbed will be used to conduct these mobile satcom experiments. The goals of the ACTS Mobile Experiments Program and the individual experiment configurations and objectives are further presented.

  9. Total Hip Joint Replacement Biotelemetry System

    NASA Technical Reports Server (NTRS)

    Boreham, J. F.; Postal, R. B.; Luntz, R. A.

    1981-01-01

    The development of a biotelemetry system that is hermetically sealed within a total hip replacement implant is reported. The telemetry system transmits six channels of stress data to reconstruct the major forces acting on the neck of the prosthesis and uses an induction power coupling technique to eliminate the need for internal batteries. The activities associated with the telemetry microminiaturization, data recovery console, hardware fabrications, power induction systems, electrical and mechanical testing and hermetic sealing test results are discussed.

  10. The ACTS propagation program

    NASA Technical Reports Server (NTRS)

    Chakraborty, D.; Davarian, Faramaz

    1992-01-01

    The success or failure of the ACTS experiment will depend on how accurately the rain-fade statistics and fade dynamics can be predicted in order to derive an appropriate algorithm that will combat weather vagaries, specifically for links with small terminals, such as very small aperture terminals (VSAT's) where the power margin is a premium. The planning process and hardware development program that will comply with the recommendations of the ACTS propagation study groups are described.

  11. Total synthesis of clostrubin

    PubMed Central

    Yang, Ming; Li, Jian; Li, Ang

    2015-01-01

    Clostrubin is a potent antibiotic against methicillin- and vancomycin-resistant bacteria that was isolated from a strictly anaerobic bacterium Clostridium beijerinckii in 2014. This polyphenol possesses a fully substituted arene moiety on its pentacyclic scaffold, which poses a considerable challenge for chemical synthesis. Here we report the first total synthesis of clostrubin in nine steps (the longest linear sequence). A desymmetrization strategy is exploited based on the inherent structural feature of the natural product. Barton–Kellogg olefination forges the two segments together to form a tetrasubstituted alkene. A photo-induced 6π electrocyclization followed by spontaneous aromatization constructs the hexasubstituted B ring at a late stage. In total, 200 mg of clostrubin are delivered through this approach. PMID:25759087

  12. Total Synthesis of Millingtonine.

    PubMed

    Brown, Patrick D; Lawrence, Andrew L

    2016-07-11

    Millingtonine is a glycosidic alkaloid that exists as a pair of pseudo-enantiomeric diastereomers. Consideration of the likely biosynthetic origins of this unusual natural product has resulted in the development of a seven-step total synthesis. Results from this synthetic work provide evidence in support of a proposed network of biosynthetic pathways that can account for the formation of several phenylethanoid natural products. PMID:27249628

  13. Total synthesis of teixobactin

    NASA Astrophysics Data System (ADS)

    Jin, Kang; Sam, Iek Hou; Po, Kathy Hiu Laam; Lin, Du'an; Ghazvini Zadeh, Ebrahim H.; Chen, Sheng; Yuan, Yu; Li, Xuechen

    2016-08-01

    To cope with the global bacterial multidrug resistance, scientific communities have devoted significant efforts to develop novel antibiotics, particularly those with new modes of actions. Teixobactin, recently isolated from uncultured bacteria, is considered as a promising first-in-class drug candidate for clinical development. Herein, we report its total synthesis by a highly convergent Ser ligation approach and this strategy allows us to prepare several analogues of the natural product.

  14. Total Syntheses of Perenniporides.

    PubMed

    Morita, Masao; Ohmori, Ken; Suzuki, Keisuke

    2015-11-20

    The total syntheses of perenniporide A (1) and related compounds have been achieved. Starting from 1,3,5-trifluorobenzene (9), difluorodienone 6 was obtained by oxidative dearomatization, which served as a platform for the high-pressure cycloaddition and for the introduction of the C3-methoxy group. The synthesis allowed access to the natural congeners 2 and 3, enabling assignment of the absolute structures of these natural products. PMID:26555442

  15. Total synthesis of teixobactin.

    PubMed

    Jin, Kang; Sam, Iek Hou; Po, Kathy Hiu Laam; Lin, Du'an; Ghazvini Zadeh, Ebrahim H; Chen, Sheng; Yuan, Yu; Li, Xuechen

    2016-01-01

    To cope with the global bacterial multidrug resistance, scientific communities have devoted significant efforts to develop novel antibiotics, particularly those with new modes of actions. Teixobactin, recently isolated from uncultured bacteria, is considered as a promising first-in-class drug candidate for clinical development. Herein, we report its total synthesis by a highly convergent Ser ligation approach and this strategy allows us to prepare several analogues of the natural product. PMID:27484680

  16. Total synthesis of teixobactin

    PubMed Central

    Jin, Kang; Sam, Iek Hou; Po, Kathy Hiu Laam; Lin, Du'an; Ghazvini Zadeh, Ebrahim H.; Chen, Sheng; Yuan, Yu; Li, Xuechen

    2016-01-01

    To cope with the global bacterial multidrug resistance, scientific communities have devoted significant efforts to develop novel antibiotics, particularly those with new modes of actions. Teixobactin, recently isolated from uncultured bacteria, is considered as a promising first-in-class drug candidate for clinical development. Herein, we report its total synthesis by a highly convergent Ser ligation approach and this strategy allows us to prepare several analogues of the natural product. PMID:27484680

  17. Cementless total hip arthroplasty.

    PubMed

    Morscher, E W

    1983-12-01

    The differences between prostheses fixed with and without cement are mainly in the design and nature of the surface implant. The shapes of the sockets to be implanted without cement show a wide variety: cylinder, square, conus, and ellipsoid with and without threads. The hemispheric shape, however, which was chosen for the acetabular component of the isoelastic hip joint, does not disturb the natural form and function of the hip joint since the outer surface is closely adapted to the original subchondral bone layer. The noncemented cup is secured by threads, pegs, screws, etc., and by ingrowth of bony tissue in the grooves of the surfaces. Most femoral stems are based on the self-locking principle. All prosthetic models incorporate attempts to increase the surface of the stem (ribs, wings, corrugations, rims, etc.). There is a tendency to use less rigid elastic implants instead of the well known rigid metallic prostheses. The aim is to overcome the problems of stress protection and stress concentration observed with rigid implants. For the biomechanical integration of an implant, the properties of the surface, especially macroporosity and microporosity, are important. Most European models of noncemented endoprostheses are based on macroporosity (porometal, madreporic, etc.). The increase in implant surface area achieved with macroscopic perforations and recesses is relatively minor compared with the possibilities offered by microporosity ("alumine fritée," Proplast, fiber-metal, etc.). The best indication for use of a cementless hip endoprosthesis is in revision arthroplasty. The lost bone stock is replaced by bone grafts, thereby creating a situation comparable with that of a primary arthroplasty. Clinical experience with noncemented hip endoprostheses is, to date, promising, although the observation time for most models is short. PMID:6357588

  18. Total Shoulder Arthroplasty

    PubMed Central

    Sanchez-Sotelo, Joaquin

    2011-01-01

    Shoulder arthroplasty has been the subject of marked advances over the last few years. Modern implants provide a wide range of options, including resurfacing of the humeral head, anatomic hemiarthroplasty, total shoulder arthroplasty, reverse shoulder arthroplasty and trauma-specific implants for fractures and nonunions. Most humeral components achieve successful long-term fixation without bone cement. Cemented all-polyethylene glenoid components remain the standard for anatomic total shoulder arthroplasty. The results of shoulder arthroplasty vary depending on the underlying diagnosis, the condition of the soft-tissues, and the type of reconstruction. Total shoulder arthroplasty seems to provide the best outcome for patients with osteoarthritis and inflammatory arthropathy. The outcome of hemiarthroplasty for proximal humerus fractures is somewhat unpredictable, though it seems to have improved with the use of fracture-specific designs, more attention to tuberosity repair, and the selective use of reverse arthroplasty, as well as a shift in indications towards internal fixation. Reverse shoulder arthroplasty has become extremely popular for patients with cuff-tear arthropathy, and its indications have been expanded to the field of revision surgery. Overall, shoulder arthroplasty is a very successful procedure with predictable pain relief and substantial improvements in motion and function. PMID:21584206

  19. Physician Update: Total Health

    PubMed Central

    Tuso, Phillip

    2014-01-01

    As an integrated prepaid health care system, Kaiser Permanente (KP) is in a unique position to demonstrate that affordability in health care can be achieved by disease prevention. During the past decade, KP has significantly improved the quality care outcomes of its members with preventable diseases. However, because of an increase in the incidence of preventable disease, and the potential long-term and short-term costs associated with the treatment of preventable disease, KP has developed a new strategy called Total Health to meet the current and future needs of its patients. Total Health means healthy people in healthy communities. KP’s strategic vision is to be a leader in Total Health by making lives better. KP hopes to make lives better by 1) measuring vital signs of health, 2) promoting healthy behaviors, 3) monitoring disease incidence, 4) spreading leading practices, and 5) creating healthy environments with our community partners. Best practices, spread to the communities we serve, will make health care more affordable, prevent preventable diseases, and save lives. PMID:24694316

  20. The interaction of a metal deactivator with metal surfaces

    SciTech Connect

    Schreifels, J.A. ); Morris, R.E.; Turner, N.H.; Mowery, R.L. )

    1990-01-01

    In modern aircraft fuel systems, the fuel is used as a heat transfer medium to dissipate heat from the avionics and hydraulic systems. Under these conditions, the fuel can undergo autooxidations. Autooxidations of net fuel can result in the formation of insoluble gum and sediment which can impair operation of the jet engine. Metal deactivator additives (MDA) were developed to counteract the catalytic activity of dissolved metals. The authors have directed their efforts at ascertaining the various mechanisms by which MDA can act, particularly in accelerated stability testing. One objective of this study was to determine to what extent interactions with metal surfaces of the test apparent govern the effectiveness of metal deactivators. This paper describes an examination of metal surfaces exposed to MDA solutions to determine under what, if any, conditions metal passivation can occur.

  1. The CEO's second act.

    PubMed

    Nadler, David A

    2007-01-01

    When a CEO leaves because of performance problems, the company typically recruits someone thought to be better equipped to fix what the departing executive couldn't--or wouldn't. The board places its confidence in the new person because of the present dilemma's similarity to some previous challenge that he or she dealt with successfully. But familiar problems are inevitably succeeded by less familiar ones, for which the specially selected CEO is not quite so qualified. More often than not, the experiences, skills, and temperament that yielded triumph in Act I turn out to be unequal to Act II's difficulties. In fact, the approaches that worked so brilliantly in Act I may be the very opposite of what is needed in Act II. The CEO has four choices: refuse to change, in which case he or she will be replaced; realize that the next act requires new skills and learn them; downsize or circumscribe his or her role to compensate for deficiencies; or line up a successor who is qualified to fill a role to which the incumbent's skills and interests are no longer suited. Hewlett-Packard's Carly Fiorina exemplifies the first alternative; Merrill Lynch's Stanley O'Neal the second; Google's Sergey Brin and Larry Page the third; and Quest Diagnostics' Ken Freeman the fourth. All but the first option are reasonable responses to the challenges presented in the second acts of most CEOs' tenures. And all but the first require a power of observation, a propensity for introspection, and a strain of humility that are rare in the ranks of the very people who need those qualities most. There are four essential steps executives can take to discern that they have entered new territory and to respond accordingly: recognition that their leadership style and approach are no longer working; acceptance of others' advice on why performance is faltering; analysis and understanding of the nature of the Act II shift; and, finally, decision and action. PMID:17286076

  2. Total hydrocarbon analyzer evaluation study

    SciTech Connect

    Shamat, N. ); Crumpler, E. ); Roddan, A. )

    1991-10-01

    Measuring and controlling organic emissions from incineration processes has become a major environmental concern in recent years. The US Environmental Protection Agency (EPA) recently proposed a regulation for sewage sludge incinerators under section 405(d) of the Clean Water Act that will require all sludge incinerators to monitor total hydrocarbon emissions (THCs) on a continuous basis. Such a requirement would be part of National Pollutant Discharge Elimination (NPDES) permits and site-specific THC limits would be established for facilities based on a risk assessment of organic emissions. Before EPA can finalize the proposed requirement, THC monitoring must be successfully conducted in a plant environment and the system required by any final regulation must be kept in operation so that facilities can comply with their permits. The Metropolitan Waste Control Commission (MWCC) in St. Paul, Minn., and Rosemount Analytical Division in La Habre, Calif., entered into a joint agreement with EPA to demonstrate a hot' THC monitoring system to detect THCs in stack gases. The objectives of the study are to determine the feasibility of THC monitoring of sludge incinerator emissions; evaluate the long term reliability, cost of operation, and consistency of a continuous THC monitoring system in an incinerator environment; and determine the correlation of THC stack concentration to incinerator and scrubber operating conditions, carbon monoxide concentration, and specific VOC emissions.

  3. Total photoabsorption in nuclei

    SciTech Connect

    Bianchi, N.

    1992-06-01

    The Frascati-Genova collaboration proposes to measure the total photonuclear cross section on a wide range of nuclei between 500 MeV and 2 GeV, to obtain informations on the interaction of baryon resonances with nucleons and on the onset of the shadowing effect. The experiment could be performed in the Hall B as soon as the tagging facility will be ready and before the end of the installation of the CLAS spectrometer. The requirements for the photon beam, like maximum energy, intensity and beam definition, are not so strong so that the experiment would also be a good first test of the tagged photon facility.

  4. Total Synthesis of Teixobactin.

    PubMed

    Giltrap, Andrew M; Dowman, Luke J; Nagalingam, Gayathri; Ochoa, Jessica L; Linington, Roger G; Britton, Warwick J; Payne, Richard J

    2016-06-01

    The first total synthesis of the cyclic depsipeptide natural product teixobactin is described. Synthesis was achieved by solid-phase peptide synthesis, incorporating the unusual l-allo-enduracididine as a suitably protected synthetic cassette and employing a key on-resin esterification and solution-phase macrolactamization. The synthetic natural product was shown to possess potent antibacterial activity against a range of Gram-positive pathogenic bacteria, including a virulent strain of Mycobacterium tuberculosis and methicillin-resistant Staphylococcus aureus (MRSA). PMID:27191730

  5. Cementless total knee arthroplasty

    PubMed Central

    Risitano, Salvatore; Sabatini, Luigi; Giachino, Matteo; Agati, Gabriele; Massè, Alessandro

    2016-01-01

    Interest for uncemented total knee arthroplasty (TKA) has greatly increased in recent years. This technique, less used than cemented knee replacement in the last decades, sees a revival thanks an advance in prosthetic design, instrumentation and operative technique. The related literature in some cases shows conflicting data on survival and on the revision’s rate, but in most cases a success rate comparable to cemented TKA is reported. The optimal fixation in TKA is a subject of debate with the majority of surgeons favouring cemented fixation. PMID:27162779

  6. Total Synthesis of Hyperforin.

    PubMed

    Ting, Chi P; Maimone, Thomas J

    2015-08-26

    A 10-step total synthesis of the polycyclic polyprenylated acylphloroglucinol (PPAP) natural product hyperforin from 2-methylcyclopent-2-en-1-one is reported. This route was enabled by a diketene annulation reaction and an oxidative ring expansion strategy designed to complement the presumed biosynthesis of this complex meroterpene. The described work enables the preparation of a highly substituted bicyclo[3.3.1]nonane-1,3,5-trione motif in only six steps and thus serves as a platform for the construction of easily synthesized, highly diverse PPAPs modifiable at every position. PMID:26252484

  7. Total Synthesis of (-)-Daphenylline.

    PubMed

    Yamada, Ryosuke; Adachi, Yohei; Yokoshima, Satoshi; Fukuyama, Tohru

    2016-05-10

    Total synthesis of (-)-daphenylline, a hexacyclic Daphniphyllum alkaloid, was achieved. Construction of the tricyclic DEF ring system was initiated by asymmetric Negishi coupling followed by an intramolecular Friedel-Crafts reaction. Installation of a side chain onto the tricyclic core was carried out through Sonogashira coupling, stereocontrolled Claisen rearrangement by taking advantage of the characteristic conformation of the tricyclic DEF core, and the stereoselective alkylation of a lactone. After the introduction of a glycine unit, the ABC ring system was stereoselectively constructed through intramolecular cycloaddition of the cyclic azomethine ylide. PMID:27062676

  8. Total Synthesis of (-)-Exiguolide.

    PubMed

    Zhang, Zhigao; Xie, Hengmu; Li, Hongze; Gao, Lu; Song, Zhenlei

    2015-10-01

    A concise total synthesis of (-)-exiguolide has been completed in an overall 2.8% yield over 20 steps in the longest linear path. The key strategies involve (1) Prins cyclization/homobromination of dienyl alcohol with the B ring-substituted aldehyde, prepared by Prins cyclization/bromination, to construct the A ring with excellent cis-Z stereochemical control and (2) an unusual side chain installation/macrocyclization strategy featuring Sonogashira cross-coupling followed by a ring-closing metathesis reaction to deliver the target. PMID:26371396

  9. Immediate total tooth replacement.

    PubMed

    Garber, D A; Salama, M A; Salama, H

    2001-03-01

    Successful implant placement at the time of extraction has been documented. Implant placement at the time of extraction was initially performed as a two-stage procedure often with barrier membranes and sophisticated second-stage surgical uncoverings. The authors describe the next generation of this technique, including atraumatic tooth removal with simultaneous root form, implant placement, and temporization at one appointment. This technique of "Immediate Total Tooth Replacement" allows for the maintenance of the bony housing and soft-tissue form that existed before extraction, while at the same time establishing a root form anchor in the bone for an esthetic restoration. PMID:11913258

  10. Metal speciation by Donnan dialysis

    SciTech Connect

    Cox, J.A.; Slonawska, K.; Gatchell, D.K.; Hiebert, A.G.

    1984-04-01

    In Donnan dialysis aqueous samples are separated from receiver electrolytes by an ion exchange membrane. The present work demonstrates that the dialysis of metals into salt solutions occurs in proportion to the sum of the concentrations of the free metal and the metal held in the form of labile complexes; however, with strongly acidic or chelating receivers, the dialysis occurs in proportion to the total soluble metal. Hence, Donnan dialysis provides the basis for a rapid estimation of the total soluble (i.e., free plus labile complexed) metal and nonlabile-complexed metal. The method is demonstrated with Pb, Zn, Cu, and Cd complexes of glycine, humic acid, and nitrilotriacetic acid and is applied to a lake water sample. The results are compared to values obtained from an established approach that utilizes stripping voltammetry and separations with a chelating ion exchange resin.

  11. Metal inks

    DOEpatents

    Ginley, David S; Curtis, Calvin J; Miedaner, Alex; van Hest, Marinus Franciscus Antonius Maria; Kaydanova, Tatiana

    2014-02-04

    Self-reducing metal inks and systems and methods for producing and using the same are disclosed. In an exemplary embodiment, a method may comprise selecting metal-organic (MO) precursor, selecting a reducing agent, and dissolving the MO precursor and the reducing agent in an organic solvent to produce a metal ink that remains in a liquid phase at room temperature. Metal inks, including self-reducing and fire-through metal inks, are also disclosed, as are various applications of the metal inks.

  12. Ototoxicity of Divalent Metals.

    PubMed

    Roth, Jerome A; Salvi, Richard

    2016-08-01

    Excess exposure to both essential and non-essential heavy metals can lead to a variety of adverse clinical conditions which selectively affect a variety of organs and cells in the body. The diverse, but highly specific nature of the symptoms produced by each metal indicates that they can interact with a restricted population of cellular targets ultimately resulting in unique clinical manifestations. The symptoms, which can be reversible or irreversible, often present with different patterns and outcomes depending on the net accumulated dose of any given metal. There are some common pathological conditions that result from excess exposure to heavy metals which unfortunately have not received widespread recognition and thus, have not been extensively investigated. For example, chronic exposure to several heavy metals such as Co, Mn, Cd, Pb, and Hg has the potential to affect hearing in humans and experimental animals based on previous studies including case reports and ex vivo studies. Understanding exactly how these metals induce hearing deficits is complicated by the fact that the inner ear is an extremely complex system that composed of a diverse collection of sensory, neural, and supporting cells which must act in synchrony to produce a neurophysiological signal terminating in the central auditory system. This review will focus on the anatomical, cellular, and functional changes that occur in the cochlea, the sensory organ for hearing, due to excessive exposure to manganese, cadmium, cobalt, lead, and mercury. PMID:27142062

  13. Anisotropic Total Variation Filtering

    SciTech Connect

    Grasmair, Markus; Lenzen, Frank

    2010-12-15

    Total variation regularization and anisotropic filtering have been established as standard methods for image denoising because of their ability to detect and keep prominent edges in the data. Both methods, however, introduce artifacts: In the case of anisotropic filtering, the preservation of edges comes at the cost of the creation of additional structures out of noise; total variation regularization, on the other hand, suffers from the stair-casing effect, which leads to gradual contrast changes in homogeneous objects, especially near curved edges and corners. In order to circumvent these drawbacks, we propose to combine the two regularization techniques. To that end we replace the isotropic TV semi-norm by an anisotropic term that mirrors the directional structure of either the noisy original data or the smoothed image. We provide a detailed existence theory for our regularization method by using the concept of relaxation. The numerical examples concluding the paper show that the proposed introduction of an anisotropy to TV regularization indeed leads to improved denoising: the stair-casing effect is reduced while at the same time the creation of artifacts is suppressed.

  14. TOTAL user manual

    NASA Technical Reports Server (NTRS)

    Johnson, Sally C.; Boerschlein, David P.

    1994-01-01

    Semi-Markov models can be used to analyze the reliability of virtually any fault-tolerant system. However, the process of delineating all of the states and transitions in the model of a complex system can be devastatingly tedious and error-prone. Even with tools such as the Abstract Semi-Markov Specification Interface to the SURE Tool (ASSIST), the user must describe a system by specifying the rules governing the behavior of the system in order to generate the model. With the Table Oriented Translator to the ASSIST Language (TOTAL), the user can specify the components of a typical system and their attributes in the form of a table. The conditions that lead to system failure are also listed in a tabular form. The user can also abstractly specify dependencies with causes and effects. The level of information required is appropriate for system designers with little or no background in the details of reliability calculations. A menu-driven interface guides the user through the system description process, and the program updates the tables as new information is entered. The TOTAL program automatically generates an ASSIST input description to match the system description.

  15. The ACTS multibeam antenna

    NASA Astrophysics Data System (ADS)

    Regier, Frank A.

    1992-06-01

    The Advanced Communications Technology Satellite (ACTS) to be launched in 1993 is briefly introduced. Its multibeam antenna, consisting of electrically similar 30 GHz receive and 20 GHz transmit offset Cassegrain systems, both utilizing orthogonal polarizations, is described. Dual polarization is achieved by using one feed assembly for each polarization in conjunction with nested front and back subreflectors, the gridded front subreflector acting as a window for one polarization and a reflector for the other. The antennas produce spot beams with approximately 0.3 degree beamwidth and gains of approximately 50 dbi. High surface accuracy and high edge taper produce low sidelobe levels and high cross-polarization isolation. A brief description is given of several Ka-band components fabricated for ACTS. These include multiflare antenna feedhorns, beam-forming networks utilizing latching ferrite waveguide switches, a 30 GHz HEMT low-noise amplifier and a 20 GHz TWT power amplifier.

  16. The ACTS multibeam antenna

    NASA Technical Reports Server (NTRS)

    Regier, Frank A.

    1992-01-01

    The Advanced Communications Technology Satellite (ACTS) to be launched in 1993 is briefly introduced. Its multibeam antenna, consisting of electrically similar 30 GHz receive and 20 GHz transmit offset Cassegrain systems, both utilizing orthogonal polarizations, is described. Dual polarization is achieved by using one feed assembly for each polarization in conjunction with nested front and back subreflectors, the gridded front subreflector acting as a window for one polarization and a reflector for the other. The antennas produce spot beams with approximately 0.3 degree beamwidth and gains of approximately 50 dbi. High surface accuracy and high edge taper produce low sidelobe levels and high cross-polarization isolation. A brief description is given of several Ka-band components fabricated for ACTS. These include multiflare antenna feedhorns, beam-forming networks utilizing latching ferrite waveguide switches, a 30 GHz HEMT low-noise amplifier and a 20 GHz TWT power amplifier.

  17. Affordable Care Act.

    PubMed

    Rak, Sofija; Coffin, Janis

    2013-01-01

    The Patient Protection and Affordable Care Act of 2010 (PPACA), although a subject of much debate in the Unites States, was enacted on March 23, 2010, and upheld by the Supreme Court on June 28, 2012. This act advocates that "healthcare is a right, not a privilege." The main goals of PPACA are to minimize the number of uninsured Americans and make healthcare available to everyone at an affordable price. The Congressional Budget Office has determined that 94% of Americans will have healthcare coverage while staying under the $900 billion limit that President Barack Obama established by bending the healthcare cost curve and reducing the deficit over the next 10 years. PMID:23767130

  18. BIOAVAILABILITY OF METALS IN CONTAMINATED SOIL AND DUST

    EPA Science Inventory

    Due to widespread metal contamination, it is necessary to characterize soils suspected of metal contamination and determine if the metal levels in these soils pose a hazard. Metal toxicity is often not directly related to the total concentration of metals present due to a numb...

  19. Total organic carbon analyzer

    NASA Technical Reports Server (NTRS)

    Godec, Richard G.; Kosenka, Paul P.; Smith, Brian D.; Hutte, Richard S.; Webb, Johanna V.; Sauer, Richard L.

    1991-01-01

    The development and testing of a breadboard version of a highly sensitive total-organic-carbon (TOC) analyzer are reported. Attention is given to the system components including the CO2 sensor, oxidation reactor, acidification module, and the sample-inlet system. Research is reported for an experimental reagentless oxidation reactor, and good results are reported for linearity, sensitivity, and selectivity in the CO2 sensor. The TOC analyzer is developed with gravity-independent components and is designed for minimal additions of chemical reagents. The reagentless oxidation reactor is based on electrolysis and UV photolysis and is shown to be potentially useful. The stability of the breadboard instrument is shown to be good on a day-to-day basis, and the analyzer is capable of 5 sample analyses per day for a period of about 80 days. The instrument can provide accurate TOC and TIC measurements over a concentration range of 20 ppb to 50 ppm C.

  20. Total synthesis of atropurpuran.

    PubMed

    Gong, Jing; Chen, Huan; Liu, Xiao-Yu; Wang, Zhi-Xiu; Nie, Wei; Qin, Yong

    2016-01-01

    Due to their architectural intricacy and biological significance, the synthesis of polycyclic diterpenes and their biogenetically related alkaloids have been the subject of considerable interest over the last few decades, with progress including the impressive synthesis of several elusive targets. Despite tremendous efforts, conquering the unique structural types of this large natural product family remains a long-term challenge. The arcutane diterpenes and related alkaloids, bearing a congested tetracyclo[5.3.3.0(4,9).0(4,12)]tridecane unit, are included in these unsolved enigmas. Here we report a concise approach to the construction of the core structure of these molecules and the first total synthesis of (±)-atropurpuran. Pivotal features of the synthesis include an oxidative dearomatization/intramolecular Diels-Alder cycloaddition cascade, sequential aldol and ketyl-olefin cyclizations to assemble the highly caged framework, and a chemoselective and stereoselective reduction to install the requisite allylic hydroxyl group in the target molecule. PMID:27387707

  1. Cervical Total Disc Arthroplasty

    PubMed Central

    Basho, Rahul; Hood, Kenneth A.

    2012-01-01

    Symptomatic adjacent segment degeneration of the cervical spine remains problematic for patients and surgeons alike. Despite advances in surgical techniques and instrumentation, the solution remains elusive. Spurred by the success of total joint arthroplasty in hips and knees, surgeons and industry have turned to motion preservation devices in the cervical spine. By preserving motion at the diseased level, the hope is that adjacent segment degeneration can be prevented. Multiple cervical disc arthroplasty devices have come onto the market and completed Food and Drug Administration Investigational Device Exemption trials. Though some of the early results demonstrate equivalency of arthroplasty to fusion, compelling evidence of benefits in terms of symptomatic adjacent segment degeneration are lacking. In addition, non-industry-sponsored studies indicate that these devices are equivalent to fusion in terms of adjacent segment degeneration. Longer-term studies will eventually provide the definitive answer. PMID:24353955

  2. Total synthesis of atropurpuran

    PubMed Central

    Gong, Jing; Chen, Huan; Liu, Xiao-Yu; Wang, Zhi-Xiu; Nie, Wei; Qin, Yong

    2016-01-01

    Due to their architectural intricacy and biological significance, the synthesis of polycyclic diterpenes and their biogenetically related alkaloids have been the subject of considerable interest over the last few decades, with progress including the impressive synthesis of several elusive targets. Despite tremendous efforts, conquering the unique structural types of this large natural product family remains a long-term challenge. The arcutane diterpenes and related alkaloids, bearing a congested tetracyclo[5.3.3.04,9.04,12]tridecane unit, are included in these unsolved enigmas. Here we report a concise approach to the construction of the core structure of these molecules and the first total synthesis of (±)-atropurpuran. Pivotal features of the synthesis include an oxidative dearomatization/intramolecular Diels-Alder cycloaddition cascade, sequential aldol and ketyl-olefin cyclizations to assemble the highly caged framework, and a chemoselective and stereoselective reduction to install the requisite allylic hydroxyl group in the target molecule. PMID:27387707

  3. Metallization failures

    NASA Technical Reports Server (NTRS)

    Beatty, R.

    1971-01-01

    Metallization-related failure mechanisms were shown to be a major cause of integrated circuit failures under accelerated stress conditions, as well as in actual use under field operation. The integrated circuit industry is aware of the problem and is attempting to solve it in one of two ways: (1) better understanding of the aluminum system, which is the most widely used metallization material for silicon integrated circuits both as a single level and multilevel metallization, or (2) evaluating alternative metal systems. Aluminum metallization offers many advantages, but also has limitations particularly at elevated temperatures and high current densities. As an alternative, multilayer systems of the general form, silicon device-metal-inorganic insulator-metal, are being considered to produce large scale integrated arrays. The merits and restrictions of metallization systems in current usage and systems under development are defined.

  4. On total disc replacement.

    PubMed

    Berg, Svante

    2011-02-01

    Low back pain consumes a large part of the community's resources dedicated to health care and sick leave. Back disorders also negatively affect the individual leading to pain suffering, decreased quality-of-life and disability. Chronic low back pain (CLBP) due to degenerative disc disease (DDD) is today often treated with fusion when conservative treatment has failed and symptoms are severe. This treatment is as successful as arthroplasty is for hip arthritis in restoring the patient's quality of life and reducing disability. Even so, there are some problems with this treatment, one of these being recurrent CLBP from an adjacent segment (ASD) after primarily successful surgery. This has led to the development of alternative surgical treatments and devices that maintain or restore mobility, in order to reduce the risk for ASD. Of these new devices, the most frequently used are the disc prostheses used in Total Disc Replacement (TDR). This thesis is based on four studies comparing total disc replacement with posterior fusion. The studies are all based on a material of 152 patients with DDD in one or two segments, aged 20-55 years that were randomly treated with either posterior fusion or TDR. The first study concerned clinical outcome and complications. Follow-up was 100% at both one and two years. It revealed that both treatment groups had a clear benefit from treatment and that patients with TDR were better in almost all outcome scores at one-year follow-up. Fusion patients continued to improve during the second year. At two-year follow-up there was a remaining difference in favour of TDR for back pain. 73% in the TDR group and 63% in the fusion group were much better or totally pain-free (n.s.), while twice as many patients in the TDR group were totally pain free (30%) compared to the fusion group (15%). Time of surgery and total time in hospital were shorter in the TDR group. There was no difference in complications and reoperations, except that seventeen of the

  5. METAL PHTHALOCYANINES

    DOEpatents

    Frigerio, N.A.

    1962-03-27

    A process is given for preparing heavy metal phthalocyanines, sulfonated or not. The process comprises mixing an inorganic metal salt with dimethyl formamide or methyl sulfoxide; separating the metal complex formed from the solution; mixing the complex with an equimolar amount of sodium, potassium, lithium, magnesium, or beryllium sulfonated or unsulfonated phthalocyanine whereby heavy-metal phthalocyanine crystals are formed; and separating the crystals from the solution. Uranyl, thorium, lead, hafnium, and lanthanide rare earth phthalocyanines can be produced by the process. (AEC)

  6. Acts of Endearment

    PubMed Central

    Stephens, G. Gayle

    1992-01-01

    Legitimate and clinically useful affection between physicians and patients can be nurtured by attending to duties enjoined by traditional codes of ethics. Three acts of endearment have special importance for today's family physicians: smoothing the bed of death; keeping patients' secrets; and not abandoning patients on account of incurability. PMID:20469528

  7. Respect for Acting.

    ERIC Educational Resources Information Center

    Hagen, Uta

    This book, based on the author's experience as a professional actress, is divided into three sections. The first part, "The Actor," deals with techniques the actor uses to function physically, verbally, and emotionally and discusses the actor's concept of himself and the art of acting. The second part, "The Object Exercises," consists of a series…

  8. Acting like a Pro

    ERIC Educational Resources Information Center

    Walker, Marlon A.

    2012-01-01

    The Saturday morning acting class in the Pearson Hall auditorium at Miles College boasts the school's highest attendance all year. The teacher, actress Robin Givens, was a lure few students--and others from surrounding areas--could resist. Some came to learn about their prospective field from a professional. Others were there for pointers to…

  9. Improving America's Schools Act

    NASA Technical Reports Server (NTRS)

    Cradler, John; Bridgforth, Elizabeth

    1995-01-01

    The Improving America's Schools ACT (IASA) emphasizes coherent systemic education reform, with Goals 2000 setting common standards for IASA and the recently authorized School-to-Work Program. IASA addresses the need to raise academic achievement, increase opportunities to learn, improve professional development, increase community involvement, utilize instructional applications of technology, and improve assessment, and allow more local flexibility in the use of funds.

  10. The USA PATRIOT Act.

    ERIC Educational Resources Information Center

    Minow, Mary; Coyle, Karen; Kaufman, Paula

    2002-01-01

    Explains the USA PATRIOT (Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism) Act, passed after the September 11 terrorist attacks, and its implications for libraries and patron records. Considers past dealings with the FBI; court orders; search warrants; wiretaps; and subpoenas. Includes:…

  11. ACTS Mobile Terminals

    NASA Technical Reports Server (NTRS)

    Abbe, Brian S.; Agan, Martin J.; Jedrey, Thomas C.

    1997-01-01

    The development of the Advanced Communications Technology Satellite (ACTS) Mobile Terminal (AMT) and its follow-on, the Broadband Aeronautical Terminal (BAT), have provided an excellent testbed for the evaluation of K- and Ka-band mobile satellite communications systems. An overview of both of these terminals is presented in this paper.

  12. Silicone metalization

    DOEpatents

    Maghribi, Mariam N.; Krulevitch, Peter; Hamilton, Julie

    2006-12-05

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  13. Silicone metalization

    DOEpatents

    Maghribi, Mariam N.; Krulevitch, Peter; Hamilton, Julie

    2008-12-09

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  14. Acts of kindness and acts of novelty affect life satisfaction.

    PubMed

    Buchanan, Kathryn E; Bardi, Anat

    2010-01-01

    The present experiment was designed to establish the effects of acts of kindness and acts of novelty on life satisfaction. Participants aged 18-60 took part on a voluntary basis. They were randomly assigned to perform either acts of kindness, acts of novelty, or no acts on a daily basis for 10 days. Their life satisfaction was measured before and after the 10-day experiment. As expected, performing acts of kindness or acts of novelty resulted in an increase in life satisfaction. PMID:20575332

  15. Primary total elbow arthroplasty

    PubMed Central

    Kumar, Suresh; Mahanta, Sunayan

    2013-01-01

    Background: Primary total elbow arthroplasty (TEA) is a challenging procedure for orthopedic surgeons. It is not performed as frequently as compared to hip or knee arthroplasty. The elbow is a nonweight-bearing joint; however, static loading can create forces up to three times the body weight and dynamic loading up to six times. For elderly patients with deformity and ankylosis of the elbow due to posttraumatic arthritis or rheumatoid arthritis or comminuted fracture distal humerus, arthroplasty is one of the option. The aim of this study is to analyze the role of primary total elbow arthroplasty in cases of crippling deformity of elbow. Materials and Methods: We analyzed 11 cases of TEA, between December 2002 and September 2012. There were 8 females and 3 males. The average age was 40 years (range 30-69 years). The indications for TEA were rheumatoid arthritis, comminuted fracture distal humerus with intraarticular extension, and posttraumatic bony ankylosis of elbow joint. The Baksi sloppy (semi constrained) hinge elbow prosthesis was used. Clinico-radiological followup was done at 1 month, 3 months, 6 months, 1 year, and then yearly basis. Results: In the present study, average supination was 70° (range 60-80°) and average pronation was 70° (range 60-80°). Average flexion was 135° (range 130-135°). However, in 5 cases, there was loss of 15 to 35° (average 25°) of extension (45°) out of 11 cases. The mean Mayo elbow performance score was 95.4 points (range 70-100). Arm length discrepancy was only in four patients which was 36% out of 11 cases. Clinico-radiologically all the elbows were stable except in one case and no immediate postoperative complication was noted. Radiolucency or loosening of ulnar stem was seen in 2 cases (18%) out of 11 cases, in 1 case it was noted after 5 years and in another after 10 years. In second case, revision arthroplasty was done, in which only ulnar hinge section, hinge screw and lock screw with hexagonal head were replaced

  16. ACT: A Benchmark for College Readiness, 2007-2011

    ERIC Educational Resources Information Center

    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…

  17. Implementing the Workforce Investment Act of 1998. A White Paper.

    ERIC Educational Resources Information Center

    Employment and Training Administration (DOL), Washington, DC.

    The Workforce Investment Act represents a total customer-driven overhaul of the U.S. job training system that will help employers obtain needed workers and empower job seekers to obtain the training needed for the jobs they want. The Department of Labor will implement the Workforce Investment Act in cooperation with the Department of Education.…

  18. The total artificial heart

    PubMed Central

    Cook, Jason A.; Shah, Keyur B.; Quader, Mohammed A.; Cooke, Richard H.; Kasirajan, Vigneshwar; Rao, Kris K.; Smallfield, Melissa C.; Tchoukina, Inna

    2015-01-01

    The total artificial heart (TAH) is a form of mechanical circulatory support in which the patient’s native ventricles and valves are explanted and replaced by a pneumatically powered artificial heart. Currently, the TAH is approved for use in end-stage biventricular heart failure as a bridge to heart transplantation. However, with an increasing global burden of cardiovascular disease and congestive heart failure, the number of patients with end-stage heart failure awaiting heart transplantation now far exceeds the number of available hearts. As a result, the use of mechanical circulatory support, including the TAH and left ventricular assist device (LVAD), is growing exponentially. The LVAD is already widely used as destination therapy, and destination therapy for the TAH is under investigation. While most patients requiring mechanical circulatory support are effectively treated with LVADs, there is a subset of patients with concurrent right ventricular failure or major structural barriers to LVAD placement in whom TAH may be more appropriate. The history, indications, surgical implantation, post device management, outcomes, complications, and future direction of the TAH are discussed in this review. PMID:26793338

  19. Endoscopic Total Thyroidectomy

    PubMed Central

    Duncan, Titus D.

    2009-01-01

    Background and Objective: Endoscopic neck surgery for the thyroid and parathyroid is being tested as an alternative to open thyroidectomy. The aim of this study was to determine the safety and feasibility of endoscopic transaxillary total thyroidectomy (ETTT). Methods and Results: Twenty-two consecutive patients from January 2006 to September 2008 underwent ETTT. No conversions to open were necessary. Mean age was 49.3±12.9 years, 20 were female, and 2 were male. Mean operating time was 238 minutes±72.7. Mean blood loss was 40mL±28.3mL. Mean weight of the gland was 137.05g±129.21g. The recurrent laryngeal nerve was identified with no permanent injury. Six patients developed hoarseness of the voice for a mean of 15.1±8.01 days. No patient developed tetany or hypocalcemia requiring treatment. Six patients experienced transient numbness in the anterior chest wall lasting 2 weeks in 5 patients and 2 months in one. All patients were discharged within 24 hours of admission. Conclusion: ETTT requires additional operative time compared with the open approach, but is cosmetically favorable. Visualization of the nerve and parathyroid is much better. Although the learning curve is steep, with experience the operative time will decrease. ETTT is different but safe and feasible. PMID:20202393

  20. Total disc replacement.

    PubMed

    Vital, J-M; Boissière, L

    2014-02-01

    Total disc replacement (TDR) (partial disc replacement will not be described) has been used in the lumbar spine since the 1980s, and more recently in the cervical spine. Although the biomechanical concepts are the same and both are inserted through an anterior approach, lumbar TDR is conventionally indicated for chronic low back pain, whereas cervical TDR is used for soft discal hernia resulting in cervicobrachial neuralgia. The insertion technique must be rigorous, with precise centering in the disc space, taking account of vascular anatomy, which is more complex in the lumbar region, particularly proximally to L5-S1. All of the numerous studies, including prospective randomized comparative trials, have demonstrated non-inferiority to fusion, or even short-term superiority regarding speed of improvement. The main implant-related complication is bridging heterotopic ossification with resulting loss of range of motion and increased rates of adjacent segment degeneration, although with an incidence lower than after arthrodesis. A sufficiently long follow-up, which has not yet been reached, will be necessary to establish definitively an advantage for TDR, particularly in the cervical spine. PMID:24412045

  1. Bioavailability of metals in fly ash and their bioaccumulation in naturally occurring vegetation: a pilot scale study.

    PubMed

    Maiti, Subodh Kumar; Nandhini, S

    2006-05-01

    A pilot scale study was conducted to find out the different forms of metals if fly ash (FA) and bioaccumulation of these metals in the naturally growing vegetation on FA dumps. The total, acid extractable, bioavailable and water soluble fraction of metals of Fe, Cu, Mn, Zn, Ni, Co and Pb, and their bioaccumulation coefficients (BAC) on naturally growing vegetation were determined. FA samples had a neutral pH, low electrical conductivity, low organic C and trace amounts of N and P. The relative abundance of total metals in FA were found in the order Fe >Mn >Zn >Ni >Co>Cu. The concentration of bioavailable (DTPA) metals depend on the type and nature of coal used in thermal power stations. In the water the extract solution, only Fe and Zn were found above detection limits. After one year only four species of naturally occurring herbaceous vegetation were found growing and Cynodon dactylon (grass) covered almost entire surface of the FA. Iron accumulated to the greatest extent in vegetation followed by Mn, Zn, Cu, Pb, Ni and Co. The sequence of BAC for different metals were Fe (202)>Mn(90)>Zn (63)>Pb(49)>Ni(41)>Cu(24). The experimental study revealed that Cynodon grass could be used for remediation of fly ash without any amendments, as this grass species act as metal excluder type. PMID:16779594

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

    SciTech Connect

    Smith, B.F.

    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.

  3. The total artificial heart.

    PubMed

    Meyer, A; Slaughter, M

    2011-09-01

    In the 1960s, cardiac surgeons and biomedical engineers pioneered the development of total artificial hearts (TAH) for the treatment of left and right heart failure. As we mark the 10th anniversary of the first implantation of the AbioCor device, the use of TAH has been limited, having failed to reach its envisioned potential and promise as an alternative therapy to heart transplantation. The Syncardia/CardioWest device, originally developed 30 years ago as the Jarvik TAH and later renamed the CardioWest TAH, continues to be used clinically in over 50 centers within the US and Europe having supported over 900 patients worldwide. Syncardia continues to develop TAH technology as evidenced by their recent introduction of a new portable pneumatic driver that enables patients to be discharged from the hospital. In contrast to TAH devices, continuous flow ventricular assist devices (VAD) have made tremendous technological strides and are rapidly gaining widespread clinical acceptance. The VAD technology has demonstrated extraordinary safety and reliability records through evolving technologies, advanced biocompatible materials, and improved patient management. Subsequently, the number of TAH implantations remains low compared to the growth in LVAD implants. Nonetheless, the Syncardia/CardioWest TAH remains an important and viable option for patients with severe biventricular failure and end organ dysfunction. Overall, a 79% survival rate has been achieved in patients supported with a Syncardia/CardioWest TAH as bridge-to-transplantation. In this review article, a brief history on the evolution of TAH devices, their current use and emerging use of evolving continuous flow VAD technology as chronic biventricular and TAH device systems are presented. PMID:21775941

  4. ACTS of Education

    NASA Technical Reports Server (NTRS)

    Bauer, Robert; Krawczyk, Richard; Gargione, Frank; Kruse, Hans; Vrotsos, Pete (Technical Monitor)

    2002-01-01

    Now in its ninth year of operations, the Advanced Communications Technology Satellite (ACTS) program has continued, although since May 2000 in a new operations arrangement involving a university based consortium, the Ohio Consortium for Advanced Communications Technology (OCACT), While NASA has concluded its experimental intentions of ACTS, the spacecraft's ongoing viability has permitted its further operations to provide educational opportunities to engineering and communications students interested in satellite operations, as well as a Ka-band test bed for commercial interests in utilizing Kaband space communications. The consortium has reached its first year of operations. This generous opportunity by NASA has already resulted in unique educational opportunities for students in obtaining "hands-on" experience, such as, in satellite attitude control. An update is presented on the spacecraft and consortium operations.

  5. ACTS TDMA network control

    NASA Astrophysics Data System (ADS)

    Inukai, T.; Campanella, S. J.

    This paper presents basic network control concepts for the Advanced Communications Technology Satellite (ACTS) System. Two experimental systems, called the low-burst-rate and high-burst-rate systems, along with ACTS ground system features, are described. The network control issues addressed include frame structures, acquisition and synchronization procedures, coordinated station burst-time plan and satellite-time plan changes, on-board clock control based on ground drift measurements, rain fade control by means of adaptive forward-error-correction (FEC) coding and transmit power augmentation, and reassignment of channel capacities on demand. The NASA ground system, which includes a primary station, diversity station, and master control station, is also described.

  6. [Patients' Rights Act].

    PubMed

    Haier, A J

    2016-09-01

    The new Patients' Rights Act does not reflect rights of patients as professional obligations of physicians for the first time. It adopted common longtime jurisdiction, but in some respects it is going beyond. This law clearly extended the documentation requirements of physicians, especially concerning the extent of documentation. In surgical fields the requirements for enlightening physicians were more strongly worded than in previous jurisdiction. In medical facilities it is now mandatory to establish an internal quality management system. PMID:27626814

  7. Toxic Substances Control Act

    SciTech Connect

    Not Available

    1992-05-15

    This Reference Book contains a current copy of the Toxic Substances Control Act and those regulations that implement the statute and appear to be most relevant to DOE activities. The document is provided to DOE and contractor staff for informational purposes only and should not be interpreted as legal guidance. Questions concerning this Reference Book may be directed to Mark Petts, EH-231 (202/586-2609).

  8. ACTE Wing Loads Analysis

    NASA Technical Reports Server (NTRS)

    Horn, Nicholas R.

    2015-01-01

    The Adaptive Compliant Trailing Edge (ACTE) project modified a Gulfstream III (GIII) aircraft with a new flexible flap that creates a seamless transition between the flap and the wing. As with any new modification, it is crucial to ensure that the aircraft will not become overstressed in flight. To test this, Star CCM a computational fluid dynamics (CFD) software program was used to calculate aerodynamic data for the aircraft at given flight conditions.

  9. Freedom of Information Act

    USGS Publications Warehouse

    Newman, D.J.

    2012-01-01

    The Freedom of Information Act( FOIA), 5 U.S.C.§ 552, as amended, generally provides that any person has a right to request access to Federal agency records. The USGS proactively promotes information disclosure as inherent to its mission of providing objective science to inform decisionmakers and the general public. USGS scientists disseminate up-to-date and historical scientific data that are critical to addressing national and global priorities.

  10. Directly susceptible, noncarbon metal ceramic composite crucible

    DOEpatents

    Holcombe, Jr., Cressie E.; Kiggans, Jr., James O.; Morrow, S. Marvin; Rexford, Donald

    1999-01-01

    A sintered metal ceramic crucible suitable for high temperature induction melting of reactive metals without appreciable carbon or silicon contamination of the melt. The crucible comprises a cast matrix of a thermally conductive ceramic material; a perforated metal sleeve, which serves as a susceptor for induction heating of the crucible, embedded within the ceramic cast matrix; and a thermal-shock-absorber barrier interposed between the metal sleeve and the ceramic cast matrix to allow for differential thermal expansions between the matrix and the metal sleeve and to act as a thermal-shock-absorber which moderates the effects of rapid changes of sleeve temperature on the matrix.

  11. The ACTS multibeam antenna

    NASA Astrophysics Data System (ADS)

    Regier, Frank A.

    1992-04-01

    The Advanced Communications Technology Satellite (ACTS) to be launched in 1993 introduces several new technologies including a multibeam antenna (MBA) operating at Ka-band. The satellite is introduced briefly, and then the MBA, consisting of electrically similar 30 GHz received and 20 GHz transmit offset Cassegrain systems utilizing orthogonal linear polarizations, is described. Dual polarization is achieved by using one feed assembly for each polarization in conjunction with nested front and back subreflectors, the gridded front subreflector acting as a window for one polarization and a reflector for the other. The antennas produce spot beams with approximately 0.3 deg beamwidth and gains of approximately 50 dbi. High surface accuracy and high edge taper produce low sidelobe levels and high cross-polarization isolation. A brief description is given of several Ka-band components fabricated for ACTS. These include multiflare antenna feedhorns, beam-forming networks utilizing latching ferrite waveguide switches, a 30 GHz high mobility electron transmitter (HEMT) low-noise amplifier and a 20 GHz TWT power amplifier.

  12. The ACTS multibeam antenna

    NASA Technical Reports Server (NTRS)

    Regier, Frank A.

    1992-01-01

    The Advanced Communications Technology Satellite (ACTS) to be launched in 1993 introduces several new technologies including a multibeam antenna (MBA) operating at Ka-band. The satellite is introduced briefly, and then the MBA, consisting of electrically similar 30 GHz received and 20 GHz transmit offset Cassegrain systems utilizing orthogonal linear polarizations, is described. Dual polarization is achieved by using one feed assembly for each polarization in conjunction with nested front and back subreflectors, the gridded front subreflector acting as a window for one polarization and a reflector for the other. The antennas produce spot beams with approximately 0.3 deg beamwidth and gains of approximately 50 dbi. High surface accuracy and high edge taper produce low sidelobe levels and high cross-polarization isolation. A brief description is given of several Ka-band components fabricated for ACTS. These include multiflare antenna feedhorns, beam-forming networks utilizing latching ferrite waveguide switches, a 30 GHz high mobility electron transmitter (HEMT) low-noise amplifier and a 20 GHz TWT power amplifier.

  13. Alternative bearing surfaces in total hip arthroplasty.

    PubMed

    Inzerillo, V Christopher; Garino, Jonathan P

    2003-01-01

    Polyethylene wear and extension of indications of total hip arthroplasty into younger and younger age groups have pushed manufacturers to develop more durable bearing surfaces. Standard polyethylene, the plastic used for the first 3 decades of hip replacement, virtually ceases to exist in its original form. Modifications of the processing, including sterlization in an inert environment and cross-linking, have demonstrated some improvements in wear. Hard-on-hard bearings such as ceramic-on-ceramic and metal-on-metal also have demonstrated extremely low wear. This article reviews the pros and cons of the alternative bearing options available to assist in the proper bearing selection for a particular patient. PMID:12882250

  14. Ceramic/ceramic total hip arthroplasty.

    PubMed

    Bizot, P; Nizard, R; Lerouge, S; Prudhommeaux, F; Sedel, L

    2000-01-01

    Alumina-on-alumina total hip arthroplasty has been used for 30 years, mainly in Europe. The theoretical advantages of this combination are represented by its remarkable sliding characteristics, its very low wear debris generation, and its sufficient fracture toughness. These advantages are achieved if the material is properly controlled with high density, high purity, and small grains. The authors summarize the results obtained with ceramic/ceramic total hip arthroplasty. Information is provided about in vivo behavior regarding wear debris characterization and quantification, and histological tissue examinations for inflammatory reactions, which were not encountered except when alumina debris was mixed with metal or cement. Modification of socket fixation resulted in improved clinical outcomes. With a press-fit metal shell and an alumina liner utilized for 10 years, the results are excellent especially in a young and active population. Alumina-on-alumina seems at the moment to be one of the best choices when a total hip arthroplasty has to be performed in young and active patients. PMID:11180930

  15. Determination of Total Petroleum Hydrocarbons (TPH) Using Total Carbon Analysis

    SciTech Connect

    Ekechukwu, A.A.

    2002-05-10

    Several methods have been proposed to replace the Freon(TM)-extraction method to determine total petroleum hydrocarbon (TPH) content. For reasons of cost, sensitivity, precision, or simplicity, none of the replacement methods are feasible for analysis of radioactive samples at our facility. We have developed a method to measure total petroleum hydrocarbon content in aqueous sample matrixes using total organic carbon (total carbon) determination. The total carbon content (TC1) of the sample is measured using a total organic carbon analyzer. The sample is then contacted with a small volume of non-pokar solvent to extract the total petroleum hydrocarbons. The total carbon content of the resultant aqueous phase of the extracted sample (TC2) is measured. Total petroleum hydrocarbon content is calculated (TPH = TC1-TC2). The resultant data are consistent with results obtained using Freon(TM) extraction followed by infrared absorbance.

  16. The Catalytic Enantioselective Total Synthesis of (+)-Liphagal**

    PubMed Central

    Day, Joshua J.; McFadden, Ryan M.; Virgil, Scott C.; Kolding, Helene; Alleva, Jennifer L.; Stoltz, Brian M.

    2012-01-01

    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, microwave-assisted metal catalysis, and an intramolecular aryne capture cyclization reaction. Pivotal to the successful completion of the synthesis was a sequence involving ring expansion from a [6-5-4] tricycle to a [6-7] bicyclic core followed by stereoselective hydrogenation of a sterically occluded tri-substituted olefin to establish the trans homodecalin system found in the natural product. PMID:21671325

  17. Fluxes and retention of trace metals in the Humber Estuary

    NASA Astrophysics Data System (ADS)

    Millward, G. E.; Glegg, G. A.

    1997-01-01

    The Humber Estuary is a physically dynamic system into which industrial wastes contaminated with heavy metals have been discharged for many years. The total fluxes of Cd, Cu, Fe, Ni, Pb and Zn from the Humber Estuary to the North Sea have been estimated for December 1988, May 1990 and August 1990. These fluxes have been compared to inputs into the estuary from rivers, sewage and industry as reported by the Paris Commission. A discrepancy exists between the estuarine inputs and the fluxes to the North Sea, which suggests that the estuary is acting as a trap for fine, metal-contaminated sediments. An alternative approach to flux assessment also indicates that metal retention by sediments is a major feature of the Humber Estuary. The results are discussed in the context of the recovery of the estuary from metal contamination and the consequences for the coastal zone. This critical review allows assessment of effectiveness of current management strategies and new directions for the future to be proposed.

  18. A Modern Approach to Total Wellbeing

    NASA Astrophysics Data System (ADS)

    Hadzic, Maja; Chen, Meifania; Brouwer, Rick; Dillon, Tharam

    The events of the last decades have impacted our lives and our health significantly. We expected that the technology boom will improve our lives. While this may be true in a specific context, generally speaking our societies are suffering from moral decays, terrorism fears, wars, financial crisis and unpredictable acts of nature that are increasing in frequency and in intensity. The complex nature of the world we live is impacting our health and wellbeing considerably. Our health is not only determined by our physical health but is the end product of the interplay of the physical, mental, emotional, financial, relational and spiritual events of a lifetime. In this paper we develop a framework that will help us define and measure total wellbeing of individuals in our volatile societies. This framework will help us better understand the complex nature of total wellbeing and develop effective prevention and intervention strategies.

  19. Gravitation experiments during the total solar eclipse

    SciTech Connect

    Kuusela, T.; Jaeykkae, J.; Kiukas, J.; Multamaeki, T.; Ropo, M.; Vilja, I.

    2006-12-15

    The variations of the apparent vertical direction of the gravity field were measured with horizontal gravimeters acting as tilt meters during the total solar eclipse in Turkey in March 29, 2006. Three separated locations within the path of totality were chosen for observations, two spaced apart along the center line, and one off the center line. No anomaly was observed at the furthest location from the center line. Aperiodic oscillations in tilt were recorded at the two locations on the center line. These may be related to the eclipse phenomenon. The average tilt amplitude deviation during the eclipse over all locations and in all directions was 150 nrad, which can be regarded as a mean upper limit for the eclipse related changes in the tilt.

  20. Quick acting gimbal joint

    NASA Technical Reports Server (NTRS)

    Wood, William B. (Inventor); Krch, Gary D. (Inventor)

    1993-01-01

    The present invention relates to an adjustable linkage assembly for selectively retaining the position of one member pivotable with respect to another member. More specifically, the invention relates to a linkage assembly commonly referred to as a gimbal joint, and particularly to a quick release or quick acting gimbal joint. The assembly is relatively simple in construction, compact in size, and has superior locking strength in any selected position. The device can be quickly and easily actuated, without separate tooling, by inexperienced personnel or by computer controlled equipment. It also is designed to prevent inadvertent actuation.

  1. 75 FR 63703 - Privacy Act of 1974; Privacy Act Regulation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-18

    ...The Board of Governors of the Federal Reserve System (Board) is issuing a final rule to amend its regulation implementing the Privacy Act of 1974 (Privacy Act). The primary changes concern the waiver of copying fees charged to current and former Board employees, and applicants for Board employment, for access to their records under the Privacy Act; the amendment of special procedures for the......

  2. Metallic nanoparticle synthesis within reverse micellar microemulsion systems

    NASA Astrophysics Data System (ADS)

    Kitchens, Christopher Lawrence

    The synthesis of metallic nanoparticles is integral for the advancement of the field of nanotechnology. Solution based nanomaterial synthesis is an effective method for the production of nanomaterials, particularly with the use of surfactants and other materials for directed assembly allowing control over the nanomaterials' physical properties. This dissertation presents research performed to study the synthesis of metallic nanoparticles within reverse micelle systems. A fundamental approach has been taken to carefully examine the role of each component of the reverse micelle system, specifically the surfactant, bulk solvent, and the aqueous micelle core. The role of the sodium bis(2-ethylhexyl) sulfosuccinate (AOT) surfactant is two fold. Initially, the surfactant forms reverse micelles, nano-sized water pools dispersed within the bulk organic solvent which act as nano-reactors for the chemical reduction of the metallic precursors and metallic nanoparticle synthesis. The surfactant also acts as a stabilizing agent, effectively dispersing synthesized particles in solution, preventing agglomeration. Previously it was thought that spherical reverse micelles acted as templates for nanoparticle synthesis despite the negligible effect of the initial micelle diameter on the on the diameter of nanoparticles synthesized. Rather the initial micelle diameter influences the nanoparticle growth rate. In contrast, the properties of the bulk organic solvent do influence the nanoparticle diameter. The nature of solvent interactions with the AOT surfactant tails in various liquid alkane solvents, compressed propane, and supercritical ethane demonstrates that steric stabilization of the metallic nanoparticles by the AOT surfactant determines the particle sizes synthesized, rather than the previously accepted templating effect. Time resolved UV-vis spectroscopy was used to study the kinetics of particle synthesis, Neutron Spin Echo spectroscopy and Small Angle Neutron Scattering

  3. ACTS broadband aeronautical experiment

    NASA Technical Reports Server (NTRS)

    Abbe, Brian S.; Jedrey, Thomas C.; Estabrook, Polly; Agan, Martin J.

    1993-01-01

    In the last decade, the demand for reliable data, voice, and video satellite communication links between aircraft and ground to improve air traffic control, airline management, and to meet the growing demand for passenger communications has increased significantly. It is expected that in the near future, the spectrum required for aeronautical communication services will grow significantly beyond that currently available at L-band. In anticipation of this, JPL is developing an experimental broadband aeronautical satellite communications system that will utilize NASA's Advanced Communications Technology Satellite (ACTS) as a satellite of opportunity and the technology developed under JPL's ACTS Mobile Terminal (AMT) Task to evaluate the feasibility of using K/Ka-band for these applications. The application of K/Ka-band for aeronautical satellite communications at cruise altitudes is particularly promising for several reasons: (1) the minimal amount of signal attenuation due to rain; (2) the reduced drag due to the smaller K/Ka-band antennas (as compared to the current L-band systems); and (3) the large amount of available bandwidth. The increased bandwidth available at these frequencies is expected to lead to significantly improved passenger communications - including full-duplex compressed video and multiple channel voice. A description of the proposed broadband experimental system will be presented including: (1) applications of K/Ka-band aeronautical satellite technology to U.S. industry; (2) the experiment objectives; (3) the experiment set-up; (4) experimental equipment description; and (5) industrial participation in the experiment and the benefits.

  4. 77 FR 41790 - Agency Forms Undergoing Paperwork Reduction Act Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-16

    ... as the Fertility Clinic Success Rate and Certification Act of 1992 (FCSRCA)), 42 U.S.C. 263a-1(a... increase in the total estimated burden hours due to an increase in the estimated number of responding... are no costs to the respondents other than their time. The total estimated annualized burden hours...

  5. 77 FR 40361 - Agency Forms Undergoing Paperwork Reduction Act Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-09

    ... the Fertility Clinic Success Rate and Certification Act of 1992 (FCSRCA)), 42 U.S.C. 263a-1(a... increase in the total estimated burden hours due to an increase in the estimated number of ] responding... are no costs to the respondents other than their time. The total estimated annualized burden hours...

  6. Statistical evaluation of biogeochemical variables affecting spatiotemporal distributions of multiple free metal ion concentrationsin an urban estuary

    EPA Science Inventory

    Free metal ion concentrations have been recognized as a better indicator of metal bioavailability in aquatic environments than total dissolved metal concentrations. However, our understanding of the determinants of free ion concentrations, especially in a metal mixture, is limite...

  7. Metal interactions in carcinogenesis: enhancement, inhibition

    PubMed Central

    Nordberg, Gunnar F.; Andersen, Ole

    1981-01-01

    Metals constitute a fundamentally important part of the total human environment. Since human exposure often involves complex mixtures of metal compounds and, possibly, organic compounds which may be carcinogenic per se, interactions between these compounds may add significantly to human cancer risk. Our present knowledge about these kinds of interactions is very limited. The best investigated area is benzo(a)pyrene (BP)-metal oxide particle interactions in respiratory carcinogenesis in the hamster. Metal oxide particles were also shown to modify the carcinogenic effect of nitrosamines. Several reports describe experiments in which selenium compounds exerted a generally anticarcinogenic and antimutagenic activity. Inorganic arsenic compounds, which are accepted to be carcinogenic in man, have so far been negative in animal experiments except for one recent suggested report. Several authors have, however, suggested that these compounds may act as cocarcinogens due to their inhibition of DNA repair, although animal experiments to demonstrate a cocarcinogenic effect of arsenic compounds have been negative so far, except for one preliminary report. The concentration of zinc in the diet seemed to influence both transplanted tumor growth and the carcinogenicity of several organic compounds, and the possibility of a correlation between dietary zinc and certain cancer forms in man has been suggested. Protection against development of Leydigiomas usually induced by cadmium injection was afforded by simultaneous injection of zinc salts. Nickel carcinogenesis has been reported to be antagonized by manganese, and synergism between Ni and organic carcinogens, e.g. BP, has been demonstrated. There is no firm evidence that lead may be a cocarcinogen, although some limited experimental evidence is available. Oxidizing agents have been demonstrated to increase, and reducing agents to antagonize, the mutagenic effect of chromium compounds in vitro. The content of carcinogenic and

  8. The instability of wrist joint and total wrist replacement.

    PubMed

    Ma, Jin-Xing; Xu, Yong-Qing

    2016-02-01

    Total wrist arthroplasty are not used as widely as total knee and hip replacement. The functional hands are requiring surgeons to design a durable and functional satisfying prosthesis. This article will list the main reasons that cause the failure of the prosthesis. Some remarkable and representative prostheses are listed to show the devolvement of total wrist prosthesis and their individual special innovations to fix the problems. And the second part we will discuss the part that biomechanical elements act in the total wrist replacement (TWA). Summarize and find out what the real problem is and how we can find a way to fix it. PMID:27033274

  9. 75 FR 38543 - Patent, Trademark and Copyright Acts

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-02

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Geological Survey Patent, Trademark and Copyright Acts AGENCY: Geological Survey, Interior. ACTION: Notice of..., Bridgeville, PA 15017 on U.S. Patent No. 6,485,696 B1, entitled ``Recovery/Removal of Metallic Elements...

  10. Affordable Care Act and Women

    MedlinePlus

    ... Privacy Policy FOIA Plain Writing Act No Fear Act Disclaimers Viewers & Players Assistant Secretary for Planning and Evaluation, Room 415F U.S. Department of Health and Human Services 200 Independence Avenue, SW Washington, D.C. ...

  11. Metal Detectors.

    ERIC Educational Resources Information Center

    Harrington-Lueker, Donna

    1992-01-01

    Schools that count on metal detectors to stem the flow of weapons into the schools create a false sense of security. Recommendations include investing in personnel rather than hardware, cultivating the confidence of law-abiding students, and enforcing discipline. Metal detectors can be quite effective at afterschool events. (MLF)

  12. Thermohydraulics in liquid metals

    NASA Astrophysics Data System (ADS)

    Kottowski, H. M.

    Heat transfer problems in single-phase and two-phase liquid metal forced convection flow are reviewed. Liquid metal boiling heat transfer in pool flow; and dry out heat fluxes are considered. It is shown that in technological plants working with liquid metals, superheating up to 150 C occurs, and can lead to nonstationary hydraulic transition between the single-phase and established two-phase flows. Boiling phases relative to subcooled boiling and bubble boiling have no importance for technological processes. Piston, slug and annular flow patterns dominate. On the basis of the flow patterns observed during boiling, the separate flow model principle is the only one suitable for calculating the two-phase flow pressure drop. Using this model and total pressure drop measurements, a relationship for the two-phase frictional pressure characteristic, valid for tubular and annular geometry, can be determined.

  13. The Nurse Reinvestment Act revisited.

    PubMed

    Luther, Ann P

    2007-01-01

    The United States is in the midst of a widely recognized critical nursing shortage. In 2002 the "Nurse Reinvestment Act" was passed with overwhelming bipartisan support in an effort to address this serious public health threat. The Act is due for reauthorization of funding in 2007. This paper provides a brief overview of the programs contained within the Act and describes practical ways in which members of the nursing community can take action to insure renewed support for the Act. PMID:17691598

  14. Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Schertler, Ronald J.; Gedney, Richard T.

    1992-01-01

    An overview of the NASA ACTS program is presented. The key technologies of ACTS include spot beams, on-board baseband processing and routing, wide bandwidth (900 MHz), and Ka-band transponders. The discussion covers system description, current status of the spacecraft development, ACTS earth stations, NGS traffic terminal, USAT, land and aeronautical mobiles, high data rate and propagation receive only terminals, and ACTS experiments program.

  15. Radioactive materials in recycled metals.

    PubMed

    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. PMID:7883556

  16. Acetabular Reconstruction in Total Hip Arthroplasty

    PubMed Central

    Santhanam, Siva Swaminathan; Choi, Jung Woo

    2016-01-01

    The difficulties encountered in dealing with the bone deficient acetabulum are amongst the greatest challenges in hip surgery. Acetabular reconstruction in revision total hip arthroplasty can successfully be achieved with hemispherical components featuring a porous or roughened ingrowth surface and options for placement of multiple screws for minor acetabular defect. Acetabular component selection is mostly based on the amount of bone loss present. In the presence of combined cavitary and segmental defects without superior acetabular coverage, reconstructions with a structural acetabular allograft protected by a cage or a custom-made triflange cage have been one of preferred surgical options. The use of a cage or ring over structural allograft bone for massive uncontained defects in acetabular revision can restore host bone stock and facilitate subsequent rerevision surgery to a certain extent. But high complication rates have been reported including aseptic loosening, infection, dislocation and metal failure. On the other hand, recent literature is reporting satisfactory outcomes with the use of modular augments combined with a hemispherical shell for major acetabular defect. Highly porous metals have been introduced for clinical use in arthroplasty surgery over the last decade. Their higher porosity and surface friction are ideal for acetabular revision, optimizing biological fixation. The use of trabecular metal cups in acetabular revision has yielded excellent clinical results. This article summarizes author's experience regarding revision acetabular reconstruction options following failed hip surgery including arthroplasty. PMID:27536638

  17. Acetabular Reconstruction in Total Hip Arthroplasty.

    PubMed

    Shon, Won Yong; Santhanam, Siva Swaminathan; Choi, Jung Woo

    2016-03-01

    The difficulties encountered in dealing with the bone deficient acetabulum are amongst the greatest challenges in hip surgery. Acetabular reconstruction in revision total hip arthroplasty can successfully be achieved with hemispherical components featuring a porous or roughened ingrowth surface and options for placement of multiple screws for minor acetabular defect. Acetabular component selection is mostly based on the amount of bone loss present. In the presence of combined cavitary and segmental defects without superior acetabular coverage, reconstructions with a structural acetabular allograft protected by a cage or a custom-made triflange cage have been one of preferred surgical options. The use of a cage or ring over structural allograft bone for massive uncontained defects in acetabular revision can restore host bone stock and facilitate subsequent rerevision surgery to a certain extent. But high complication rates have been reported including aseptic loosening, infection, dislocation and metal failure. On the other hand, recent literature is reporting satisfactory outcomes with the use of modular augments combined with a hemispherical shell for major acetabular defect. Highly porous metals have been introduced for clinical use in arthroplasty surgery over the last decade. Their higher porosity and surface friction are ideal for acetabular revision, optimizing biological fixation. The use of trabecular metal cups in acetabular revision has yielded excellent clinical results. This article summarizes author's experience regarding revision acetabular reconstruction options following failed hip surgery including arthroplasty. PMID:27536638

  18. ACT/SAT College Survey.

    ERIC Educational Resources Information Center

    Stafford, John E.

    1998-01-01

    Reports on findings of a survey designed to discover whether higher education institutions' admission standards accept SAT I or ACT and if there is preference for either, and whether ACT could be submitted in lieu of SAT II subject tests. Eighty-six percent of the reporting schools indicated no preference; 28 schools indicated that the ACT was an…

  19. Defining Acts of Journalistic Deception.

    ERIC Educational Resources Information Center

    Elliott, Deni; Culver, Charles M.

    To determine when, if ever, deceptive acts can be morally justified in investigative reporting, it is important to distinguish a deceptive act that is morally justified from an act that is not deceptive in the first place. This paper seeks to provide an account of what counts as deception and identify the kinds of journalistic practice that are…

  20. ACTS mobile propagation campaign

    NASA Technical Reports Server (NTRS)

    Goldhirsh, Julius; Vogel, Wolfhard J.; Torrence, Geoffrey W.

    1994-01-01

    Preliminary results are presented for three propagation measurement campaigns involving a mobile receiving laboratory and 20 GHz transmissions from the Advanced Communications Technology Satellite (ACTS). Four 1994 campaigns were executed during weekly periods in and around Austin, Texas in February and May, in Central Maryland during March, and in Fairbanks, Alaska and environs in June. Measurements tested the following effects at 20 GHz: (1) attenuation due to roadside trees with and without foliage, (2) multipath effects for scenarios in which line-of-sight paths were unshadowed, (3) fades due to terrain and roadside obstacles, (4) fades due to structures in urban environs, (5) single tree attenuation, and (6) effects of fading at low elevation angles (8 deg in Fairbanks, Alaska) and high elevation angles (55 deg in Austin, Texas). Results presented here cover sampled measurements in Austin, Texas for foliage and non-foliage cases and in Central Maryland for non-foliage runs.

  1. FAST ACTING CURRENT SWITCH

    DOEpatents

    Batzer, T.H.; Cummings, D.B.; Ryan, J.F.

    1962-05-22

    A high-current, fast-acting switch is designed for utilization as a crowbar switch in a high-current circuit such as used to generate the magnetic confinement field of a plasma-confining and heat device, e.g., Pyrotron. The device particularly comprises a cylindrical housing containing two stationary, cylindrical contacts between which a movable contact is bridged to close the switch. The movable contact is actuated by a differential-pressure, airdriven piston assembly also within the housing. To absorb the acceleration (and the shock imparted to the device by the rapidly driven, movable contact), an adjustable air buffer assembly is provided, integrally connected to the movable contact and piston assembly. Various safety locks and circuit-synchronizing means are also provided to permit proper cooperation of the invention and the high-current circuit in which it is installed. (AEC)

  2. Triple acting radial seal

    DOEpatents

    Ebert, Todd A; Carella, John A

    2012-03-13

    A triple acting radial seal used as an interstage seal assembly in a gas turbine engine, where the seal assembly includes an interstage seal support extending from a stationary inner shroud of a vane ring, the interstage seal support includes a larger annular radial inward facing groove in which an outer annular floating seal assembly is secured for radial displacement, and the outer annular floating seal assembly includes a smaller annular radial inward facing groove in which an inner annular floating seal assembly is secured also for radial displacement. A compliant seal is secured to the inner annular floating seal assembly. The outer annular floating seal assembly encapsulates the inner annular floating seal assembly which is made from a very low alpha material in order to reduce thermal stress.

  3. Caught in the Act

    NASA Technical Reports Server (NTRS)

    2005-01-01

    5 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a dust devil caught in the act of creating a dark streak on the floor of the large, south mid-latitude crater, Mendel. Dozens of other dark streaks mark the paths of earlier dust devils. Dust devil streaks at southern middle and high latitudes are seasonal features; they are erased each winter by thin deposits of dust and frost, and they are re-created each spring and summer by new dust devils.

    Location near: 58.9oS, 199.4oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  4. Osteolysis around total knee arthroplasty: a review of pathogenetic mechanisms.

    PubMed

    Gallo, J; Goodman, S B; Konttinen, Y T; Wimmer, M A; Holinka, M

    2013-09-01

    Aseptic loosening and other wear-related complications are some of the most frequent late reasons for revision of total knee arthroplasty (TKA). Periprosthetic osteolysis (PPOL) pre-dates aseptic loosening in many cases, indicating the clinical significance of this pathogenic mechanism. A variety of implant-, surgery- and host-related factors have been delineated to explain the development of PPOL. These factors influence the development of PPOL because of changes in mechanical stresses within the vicinity of the prosthetic device, excessive wear of the polyethylene liner, and joint fluid pressure and flow acting on the peri-implant bone. The process of aseptic loosening is initially governed by factors such as implant/limb alignment, device fixation quality and muscle coordination/strength. Later, large numbers of wear particles detached from TKA trigger and perpetuate particle disease, as highlighted by progressive growth of inflammatory/granulomatous tissue around the joint cavity. An increased accumulation of osteoclasts at the bone-implant interface, impairment of osteoblast function, mechanical stresses and increased production of joint fluid contribute to bone resorption and subsequent loosening of the implant. In addition, hypersensitivity and adverse reactions to metal debris may contribute to aseptic TKA failure, but should be determined more precisely. Patient activity level appears to be the most important factor when the long-term development of PPOL is considered. Surgical technique, implant design and material factors are the most important preventative factors, because they influence both the generation of wear debris and excessive mechanical stresses. New generations of bearing surfaces and designs for TKA should carefully address these important issues in extensive preclinical studies. Currently, there is little evidence that PPOL can be prevented by pharmacological intervention. PMID:23669623

  5. OSTEOLYSIS AROUND TOTAL KNEE ARTHOPLASTY: A REVIEW OF PATHOGENETIC MECHANISMS

    PubMed Central

    Gallo, Jiri; Goodman, Stuart B.; Konttinen, Yrjö T.; Wimmer, Markus A.; Holinka, Martin

    2014-01-01

    Aseptic loosening and other wear-related complications are one of the most frequent late reasons for revision of total knee arthroplasty (TKA). Periprosthetic osteolysis (PPOL) predates aseptic loosening in many cases indicating the clinical significance of this pathogenic mechanism. A variety of implant-, surgery-, and host-related factors have been delineated to explain the development of PPOL. These factors influence the development of PPOL due to changes in mechanical stresses within the vicinity of the prosthetic device, excessive wear of the polyethylene liner, and joint fluid pressure and flow acting on the peri-implant bone. The process of aseptic loosening is initially governed by factors such as implant/limb alignment, device fixation quality, and muscle coordination/strength. Later large numbers of wear particles detached from TKAs trigger and perpetuate particle disease, as highlighted by progressive growth of inflammatory/granulomatous tissue around the joint cavity. An increased accumulation of osteoclasts at the bone-implant interface, an impairment of osteoblast function, mechanical stresses, and an increased production of joint fluid contribute to bone resorption and subsequent loosening of the implant. In addition, hypersensitivity and adverse reactions to metal debris may contribute to aseptic TKA failure but should be determined more precisely. Patient activity level appears to be the most important factor when the long-term development of PPOL is considered. Surgical technique, implant design, and material factors are the most important preventative factors because they influence both the generation of wear debris and excessive mechanical stresses. New generations of bearing surfaces and designs for TKA should carefully address these important issues in extensive preclinical studies. Currently, there is little evidence that PPOL can be prevented with pharmacological interventions. PMID:23669623

  6. Metal oxide films on metal

    DOEpatents

    Wu, Xin D.; Tiwari, Prabhat

    1995-01-01

    A structure including a thin film of a conductive alkaline earth metal oxide selected from the group consisting of strontium ruthenium trioxide, calcium ruthenium trioxide, barium ruthenium trioxide, lanthanum-strontium cobalt oxide or mixed alkaline earth ruthenium trioxides thereof upon a thin film of a noble metal such as platinum is provided.

  7. Dissimilar metals joint evaluation

    NASA Technical Reports Server (NTRS)

    Wakefield, M. E.; Apodaca, L. E.

    1974-01-01

    Dissimilar metals tubular joints between 2219-T851 aluminum alloy and 304L stainless steel were fabricated and tested to evaluate bonding processes. Joints were fabricated by four processes: (1) inertia (friction) weldings, where the metals are spun and forced together to create the weld; (2) explosive welding, where the metals are impacted together at high velocity; (3) co-extrusion, where the metals are extruded in contact at high temperature to promote diffusion; and (4) swaging, where residual stresses in the metals after a stretching operation maintain forced contact in mutual shear areas. Fifteen joints of each type were prepared and evaluated in a 6.35 cm (2.50 in.) O.D. size, with 0.32 cm (0.13 in.) wall thickness, and 7.6 cm (3.0 in) total length. The joints were tested to evaluate their ability to withstand pressure cycle, thermal cycle, galvanic corrosion and burst tests. Leakage tests and other non-destructive test techniques were used to evaluate the behavior of the joints, and the microstructure of the bond areas was analyzed.

  8. Metal Coatings

    NASA Technical Reports Server (NTRS)

    1994-01-01

    During the Apollo Program, General Magnaplate Corporation developed process techniques for bonding dry lubricant coatings to space metals. The coatings were not susceptible to outgassing and offered enhanced surface hardness and superior resistance to corrosion and wear. This development was necessary because conventional lubrication processes were inadequate for lightweight materials used in Apollo components. General Magnaplate built on the original technology and became a leader in development of high performance metallurgical surface enhancement coatings - "synergistic" coatings, - which are used in applications from pizza making to laser manufacture. Each of the coatings is designed to protect a specific metal or group of metals to solve problems encountered under operating conditions.

  9. Metals 2000

    SciTech Connect

    Allison, S.W.; Rogers, L.C.; Slaughter, G.; Boensch, F.D.; Claus, R.O.; de Vries, M.

    1993-05-01

    This strategic planning exercise identified and characterized new and emerging advanced metallic technologies in the context of the drastic changes in global politics and decreasing fiscal resources. In consideration of a hierarchy of technology thrusts stated by various Department of Defense (DOD) spokesmen, and the need to find new and creative ways to acquire and organize programs within an evolving Wright Laboratory, five major candidate programs identified are: C-17 Flap, Transport Fuselage, Mach 5 Aircraft, 4.Fighter Structures, and 5. Missile Structures. These results were formed by extensive discussion with selected major contractors and other experts, and a survey of advanced metallic structure materials. Candidate structural applications with detailed metal structure descriptions bracket a wide variety of uses which warrant consideration for the suggested programs. An analysis on implementing smart skins and structures concepts is given from a metal structures perspective.

  10. Registration of heavy metal ions and pesticides with ATR planar waveguide enzyme sensors

    NASA Astrophysics Data System (ADS)

    Nabok, Alexei; Haron, Saharudin; Ray, Asim

    2004-11-01

    The proposed novel type of enzyme optical sensors is based on a combination of SiO2/Si3N4/SiO2 planar waveguide ATR (attenuated total reflection) transducer, fabricated by standard silicon planar technology, with the composite polyelectrolyte self-assembled coating containing both organic chromophores and enzyme molecules. Such devices were deployed to monitor typical industrial and agricultural water pollutants, such as heavy metal ions and pesticides, acting as inhibitors of enzyme reactions. The sensitivity of registration of these pollutants in the range of 1 ppb was achieved. The use of different enzymes in the sensitive membrane provides a background for pattern recognition of the above pollutants.

  11. Metals content in surface waters of an upwelling system of the northern Humboldt Current (Mejillones Bay, Chile)

    NASA Astrophysics Data System (ADS)

    Valdés, Jorge; Román, Domingo; Alvarez, Gabriel; Ortlieb, Luc; Guiñez, Marcos

    Physical-chemical parameters (temperature, salinity, dissolved oxygen, nutrients, and chlorophyll concentration) of surface waters were used to evaluate the influence of biological and physical processes over the metal concentrations (Cd, Ni, V, Mo, Mn, and Fe) in different periods of a normal annual cycle (June 2002 and April 2003), in Mejillones Bay (23° S), one of northern Chile's strongest upwelling cells. Two points were sampled every 2 months, but statistical analysis of these parameters did not show any spatial differences in surface water composition (annual average) in this bay. The order of total and dissolved metals by abundance (annual mean) in the Mejillones Bay surface waters during the sampling period was Cd < Ni < Mn < Fe < V < Mo. The surface concentration of metals does not appear to be explained by anthropogenic inputs (at least not during the year of this work), and variability observed in this study appears to be natural. The lack of correlation between physical-chemical parameters and metals could indicate a more complex combination of factors acting on surface concentrations. Moreover, the mixture of water masses and the Oxygen Minimum Zone which characterizes the Mejillones bay should have an important influence on surface distribution of trace metals and can explain the high temporal variability observed in most of the metals analyzed in this work. A two-box conceptual model is proposed to suggest possible influences on metals in surface waters of this coastal ecosystem.

  12. Metal-on-Metal Hip Resurfacing Arthroplasty

    PubMed Central

    Sehatzadeh, S; Kaulback, K; Levin, L

    2012-01-01

    Background Metal-on-metal (MOM) hip resurfacing arthroplasty (HRA) is in clinical use as an appropriate alternative to total hip arthroplasty in young patients. In this technique, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the acetabulum. Objectives The primary objective of this analysis was to compare the revision rates of MOM HRA using different implants with the benchmark set by the National Institute of Clinical Excellence (NICE). The secondary objective of this analysis was to review the literature regarding adverse biological effects associated with implant material. Review Methods A literature search was performed on February 13, 2012, to identify studies published from January 1, 2009, to February 13, 2012. Results The revision rates for MOM HRA using 6 different implants were reviewed. The revision rates for MOM HRA with 3 implants met the NICE criteria, i.e., a revision rate of 10% or less at 10 years. Two implants had short-term follow-ups and MOM HRA with one of the implants failed to meet the NICE criteria. Adverse tissue reactions resulting in failure of the implants have been reported by several studies. With a better understanding of the factors that influence the wear rate of the implants, adverse tissue reactions and subsequent implant failure can be minimized. Many authors have suggested that patient selection and surgical technique affect the wear rate and the risk of tissue reactions. The biological effects of high metal ion levels in the blood and urine of patients with MOM HRA implants are not known. Studies have shown an increase in chromosomal aberrations in patients with MOM articulations, but the clinical implications and long-term consequences of this increase are still unknown. Epidemiological studies have shown that patients with MOM HRA implants did not have an overall increase in mortality or risk of cancer. There is insufficient clinical data to confirm the

  13. 24 CFR 266.650 - Items deducted from total loss.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Items deducted from total loss. 266.650 Section 266.650 Housing and Urban Development Regulations Relating to Housing and Urban... HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND...

  14. 24 CFR 266.648 - Items included in total loss.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Items included in total loss. 266.648 Section 266.648 Housing and Urban Development Regulations Relating to Housing and Urban... HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND...

  15. 24 CFR 266.650 - Items deducted from total loss.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Items deducted from total loss. 266.650 Section 266.650 Housing and Urban Development Regulations Relating to Housing and Urban... HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND...

  16. 24 CFR 266.648 - Items included in total loss.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Items included in total loss. 266.648 Section 266.648 Housing and Urban Development Regulations Relating to Housing and Urban... HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND...

  17. Fast-Acting Valve

    NASA Technical Reports Server (NTRS)

    Wojciechowski, Bogdan V. (Inventor); Pegg, Robert J. (Inventor)

    2003-01-01

    A fast-acting valve includes an annular valve seat that defines an annular valve orifice between the edges of the annular valve seat, an annular valve plug sized to cover the valve orifice when the valve is closed, and a valve-plug holder for moving the annular valve plug on and off the annular valve seat. The use of an annular orifice reduces the characteristic distance between the edges of the valve seat. Rather than this distance being equal to the diameter of the orifice, as it is for a conventional circular orifice, the characteristic distance equals the distance between the inner and outer radii (for a circular annulus). The reduced characteristic distance greatly reduces the gap required between the annular valve plug and the annular valve seat for the valve to be fully open, thereby greatly reducing the required stroke and corresponding speed and acceleration of the annular valve plug. The use of a valve-plug holder that is under independent control to move the annular valve plug between its open and closed positions is important for achieving controllable fast operation of the valve.

  18. Double acting bit holder

    DOEpatents

    Morrell, Roger J.; Larson, David A.; Ruzzi, Peter L.

    1994-01-01

    A double acting bit holder that permits bits held in it to be resharpened during cutting action to increase energy efficiency by reducing the amount of small chips produced. The holder consist of: a stationary base portion capable of being fixed to a cutter head of an excavation machine and having an integral extension therefrom with a bore hole therethrough to accommodate a pin shaft; a movable portion coextensive with the base having a pin shaft integrally extending therefrom that is insertable in the bore hole of the base member to permit the moveable portion to rotate about the axis of the pin shaft; a recess in the movable portion of the holder to accommodate a shank of a bit; and a biased spring disposed in adjoining openings in the base and moveable portions of the holder to permit the moveable portion to pivot around the pin shaft during cutting action of a bit fixed in a turret to allow front, mid and back positions of the bit during cutting to lessen creation of small chip amounts and resharpen the bit during excavation use.

  19. Acting to gain information

    NASA Technical Reports Server (NTRS)

    Rosenchein, Stanley J.; Burns, J. Brian; Chapman, David; Kaelbling, Leslie P.; Kahn, Philip; Nishihara, H. Keith; Turk, Matthew

    1993-01-01

    This report is concerned with agents that act to gain information. In previous work, we developed agent models combining qualitative modeling with real-time control. That work, however, focused primarily on actions that affect physical states of the environment. The current study extends that work by explicitly considering problems of active information-gathering and by exploring specialized aspects of information-gathering in computational perception, learning, and language. In our theoretical investigations, we analyzed agents into their perceptual and action components and identified these with elements of a state-machine model of control. The mathematical properties of each was developed in isolation and interactions were then studied. We considered the complexity dimension and the uncertainty dimension and related these to intelligent-agent design issues. We also explored active information gathering in visual processing. Working within the active vision paradigm, we developed a concept of 'minimal meaningful measurements' suitable for demand-driven vision. We then developed and tested an architecture for ongoing recognition and interpretation of visual information. In the area of information gathering through learning, we explored techniques for coping with combinatorial complexity. We also explored information gathering through explicit linguistic action by considering the nature of conversational rules, coordination, and situated communication behavior.

  20. Total Quality and Organization Development. Total Quality Series.

    ERIC Educational Resources Information Center

    Lindsay, William M.; Petrick, Joseph A.

    As the global business environment becomes more turbulent, quality management seems more indispensable. This book offers strategies for integrating the theory and practice of Total Quality Management (TQM) with organizational-development (OD) theory at all organizational levels. Chapter 1 answers the question "Why Total Quality Management and…

  1. Metal ion-containing epoxies

    NASA Technical Reports Server (NTRS)

    Stoakley, D. M.; St.clair, A. K.

    1982-01-01

    A variety of metallic and organometallic complexes to be used as potential additives for an epoxy used by the aerospace industry as a composite matrix resin were investigated. A total of 9 complexes were screened for compatibility and for their ability to accelerate or inhibit the cure of a highly crosslinkable epoxy resin. Methods for combining the metallic complexes with the resin were investigated, gel times recorded, and cure exotherms studied by differential scanning calorimetry. Glass transition temperatures of cured metal ion containing epoxy castings were determined by thermomechanical analysis. Thermal stabilities of the castings were determined by thermogravimetric analysis. Mechanical strength and stiffness of these doped epoxies were also measured.

  2. 40 CFR 721.10097 - Disubstituted benzenesulfonic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES... metal salt (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as disubstituted benzenesulfonic acid, alkali metal salt (PMN...

  3. METAL SPECIATION IN SOIL, SEDIMENT, AND WATER SYSTEMS VIA SYNCHROTRON RADIATION RESEARCH

    EPA Science Inventory

    Metal contaminated environmental systems (soils, sediments, and water) have challenged researchers for many years. Traditional methods of analysis have employed extraction methods to determine total metal content and define risk based on the premise that as metal concentration in...

  4. Total zinc in zinc battery plates by EDTA titration

    SciTech Connect

    Hammersley, V.L.

    1995-07-01

    At present, zinc battery plate electrodes are analyzed for zinc oxide, zinc chloride, zinc fluoride, zinc carbonate, zinc oxychloride, total zinc, zinc as the metal, and trace metals. A variety of methods are used to determine each of these components. The amount of zinc in each of the zinc compounds is determined by multiplying the percent of the compound by the ratio of the molecular weights of zinc to the zinc compound. This percent zinc is subtracted from percent total zinc and the operation is performed for every zinc compound determined. The remaining zinc value after these subtractions represents zinc as the metal. Zinc metal is the charged state on the anode. Percent total zinc is required in all these calculations. The importance of these components cannot be overemphasized. The presence, or absence, of certain components in the zinc electrode can influence its behavior in a zinc-silver oxide primary battery. Passivation layers, tendency to dendritic growth, corrosion rates, voltage rise times, current density, porosity, surface area, electrochemical capacity, and other considerations make it imperative that the chemical composition of the zinc electrode be known. The focus of this project was to evaluate the present method for total zinc and to develop a better method.

  5. [Euthanasia and medical act].

    PubMed

    2011-05-01

    Right to life -as the prohibition of intentionally and arbitrarily taking life, even with authorization of the concerned one- is an internationally recognized right. In many countries, debate regarding euthanasia is more centered in its convenience, social acceptability and how it is regulated, than in its substantial legitimacy. Some argue that euthanasia should be included as part of clinical practice of health professionals, grounded on individual's autonomy claims-everyone having the liberty to choose how to live and how to die. Against this, others sustain that life has a higher value than autonomy, exercising autonomy without respecting the right to life would become a serious moral and social problem. Likewise, euthanasia supporters some-times claim a 'right to live with dignity', which must be understood as a personal obligation, referred more to the ethical than to the strictly legal sphere. In countries where it is already legalized, euthanasia practice has extended to cases where it is not the patient who requests this but the family or some healthcare professional, or even the legal system-when they think that the patient is living in a condition which is not worthy to live. Generalization of euthanasia possibly will end in affecting those who need more care, such as elder, chronically ill or dying people, damaging severely personal basic rights. Nature, purpose and tradition of medicine rule out the practice of euthanasia, which ought not be considered a medical act or legitimately compulsory for physicians. Today's medicine counts with effective treatments for pain and suffering, such as palliative care, including sedative therapy, which best preserves persons dignity and keeps safe the ethos of the medical profession. PMID:22051717

  6. Metallic Hydrogen

    NASA Astrophysics Data System (ADS)

    Silvera, Isaac; Zaghoo, Mohamed; Salamat, Ashkan

    2015-03-01

    Hydrogen is the simplest and most abundant element in the Universe. At high pressure it is predicted to transform to a metal with remarkable properties: room temperature superconductivity, a metastable metal at ambient conditions, and a revolutionary rocket propellant. Both theory and experiment have been challenged for almost 80 years to determine its condensed matter phase diagram, in particular the insulator-metal transition. Hydrogen is predicted to dissociate to a liquid atomic metal at multi-megabar pressures and T =0 K, or at megabar pressures and very high temperatures. Thus, its predicted phase diagram has a broad field of liquid metallic hydrogen at high pressure, with temperatures ranging from thousands of degrees to zero Kelvin. In a bench top experiment using static compression in a diamond anvil cell and pulsed laser heating, we have conducted measurements on dense hydrogen in the region of 1.1-1.7 Mbar and up to 2200 K. We observe a first-order phase transition in the liquid phase, as well as sharp changes in optical transmission and reflectivity when this phase is entered. The optical signature is that of a metal. The mapping of the phase line of this transition is in excellent agreement with recent theoretical predictions for the long-sought plasma phase transition to metallic hydrogen. Research supported by the NSF, Grant DMR-1308641, the DOE Stockpile Stewardship Academic Alliance Program, Grant DE-FG52-10NA29656, and NASA Earth and Space Science Fellowship Program, Award NNX14AP17H.

  7. The total charm cross section

    SciTech Connect

    Vogt, R

    2007-09-14

    We assess the theoretical uncertainties on the total charm cross section. We discuss the importance of the quark mass, the scale choice and the parton densities on the estimate of the uncertainty. We conclude that the uncertainty on the total charm cross section is difficult to quantify.

  8. Moving belt metal detector

    NASA Astrophysics Data System (ADS)

    Nelson, Carl V.; Mendat, Deborah P.; Huynh, Toan B.

    2006-05-01

    The Johns Hopkins University Applied Physics Laboratory (APL) has developed a prototype metal detection survey system that will increase the search speed of conventional technology while maintaining high sensitivity. Higher search speeds will reduce the time to clear roads of landmines and improvised explosive devices (IED) and to locate unexploded ordnance (UXO) at Base Realignment and Closure (BRAC) sites, thus reducing remediation costs. The new survey sensor system is called the moving belt metal detector (MBMD) and operates by both increasing sensor speed over the ground while maintaining adequate sensor dwell time over the target for good signal-to-noise ratio (SNR) and reducing motion-induced sensor noise. The MBMD uses an array of metal detection sensors mounted on a flexible belt similar to a tank track. The belt motion is synchronized with the forward survey speed so individual sensor elements remain stationary relative to the ground. A single pulsed transmitter coil is configured to provide a uniform magnetic field along the length of the receivers in ground contact. Individual time-domain electromagnetic induction (EMI) receivers are designed to sense a single time-gate measurement of the total metal content. Each sensor module consists of a receiver coil, amplifier, digitizing electronics and a low power UHF wireless transmitter. This paper presents the survey system design concepts and metal detection data from various targets at several survey speeds. Although the laboratory prototype is designed to demonstrate metal detection survey speeds up to 10 m/s, higher speeds are achievable with a larger sensor array. In addition, the concept can be adapted to work with other sensor technologies not previously considered for moving platforms.

  9. Wall effects on the electrical manipulation of metal nanowires.

    PubMed

    Loucaides, Neophytos G; Ramos, Antonio

    2015-07-01

    The rotation induced by AC electric fields on metal nanowires has been studied theoretically and experimentally. In the experiments, the nanowires rotate close to the bottom of the device. The present work studies the effects of the wall on the electrorotation and electro-orientation of a metal nanowire numerically. The induced electrical rotation of a metal nanowire in solution is originated by both the electrical torque on the induced dipole and the induced charge EOF around the particle. The theoretical analysis presented here only considers the effects of the wall on the nanowire rotation originated by the torque on the induced dipole. Two methods are employed in the analysis in order to obtain the electrical and viscous torques acting on the nanowire: (i) the 3D electrical and hydrodynamic equations are simulated using the finite element method and (ii) hydrodynamic and electrical slender-body approximations are used to obtain, respectively, line distributions of Stokeslets and charge that take into account the proximity of a plane wall. The numerical results obtained from the two methods are totally in agreement. The main wall effects are that the electrical torque is reduced, the viscous torque is increased, and an electric repulsive force from the wall appears. PMID:25640250

  10. Alaska placer mining metals study, year two

    SciTech Connect

    Goulet, J.; Frank, D.; Ryding, K.; Edmond, L.

    1999-04-01

    EPA sampled four placer mines in Alaska during the summer of 1998. This was the second phase of a study of the distribution of metals in surface water at placer mines in surface water upstream of the mine site, downstream of the mine discharge, and in the effluent. The second phase examines temporal variations from eight rounds of measurements collected during 1998 from four placer mines located in three mining districts. During the second phase in 1998, EPA obtained field measurements of temperature, pH, electrical conductivity, dissolved oxygen, turbidity, and settleable solids. In addition, EPA analyzed samples for total suspended solids, total recoverable metals, dissolved metals, and hardness. The metals analyses included aluminium, antimony, arsenic, cadmium, calcium, chromium, copper, lead, magnesium, mercury, nickel, selenium, silver, and zinc. The 1998 data show typically large variations in total recoverable and dissolved metals concentrations through the course of the mining season. Consistent with 1997 results, turbidity was an effective indicator for some, but not all, total recoverable metals found in surface waters. In addition to turbidity, total suspended solids measurements showed similar variations with total recoverable metal content.

  11. ELECTROLYTIC PROCESS FOR PRODUCING METALS

    DOEpatents

    Kopelman, B.; Holden, R.B.

    1961-06-01

    A method is described for reducing beryllium halides to beryllium. The beryllfum halide fs placed in an eutectic mixture of alkali halides and alkaline earth halides. The constituents of this eutectic bath are so chosen that it has a melting point less than the boiling point of mercury, which acts as a cathode for the system. The beryllium metal is then deposited in the mercury upon electrolysis.

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

    PubMed

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

    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(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. PMID:22321900

  13. Metal nanoshells.

    PubMed

    Hirsch, Leon R; Gobin, Andre M; Lowery, Amanda R; Tam, Felicia; Drezek, Rebekah A; Halas, Naomi J; West, Jennifer L

    2006-01-01

    Metal nanoshells are a new class of nanoparticles with highly tunable optical properties. Metal nanoshells consist of a dielectric core nanoparticle such as silica surrounded by an ultrathin metal shell, often composed of gold for biomedical applications. Depending on the size and composition of each layer of the nanoshell, particles can be designed to either absorb or scatter light over much of the visible and infrared regions of the electromagnetic spectrum, including the near infrared region where penetration of light through tissue is maximal. These particles are also effective substrates for surface-enhanced Raman scattering (SERS) and are easily conjugated to antibodies and other biomolecules. One can envision a myriad of potential applications of such tunable particles. Several potential biomedical applications are under development, including immunoassays, modulated drug delivery, photothermal cancer therapy, and imaging contrast agents. PMID:16528617

  14. Future Bearing Surfaces in Total Hip Arthroplasty

    PubMed Central

    2014-01-01

    One of the most important issues in the modern total hip arthroplasty (THA) is the bearing surface. Extensive research on bearing surfaces is being conducted to seek an ideal bearing surface for THA. The ideal bearing surface for THA should have superior wear characteristics and should be durable, bio-inert, cost-effective, and easy to implant. However, bearing surfaces that are currently being implemented do not completely fulfill these requirements, especially for young individuals for whom implant longevity is paramount. Even though various new bearing surfaces have been investigated, research is still ongoing, and only short-term results have been reported from clinical trials. Future bearing surfaces can be developed in the following ways: (1) change in design, (2) further improvement of polyethylene, (3) surface modification of the metal, (4) improvement in the ceramic, and (5) use of alternative, new materials. One way to reduce wear and impingement in THA is to make changes in its design by using a large femoral head, a monobloc metal shell with preassembled ceramic liner, dual mobility cups, a combination of different bearing surfaces, etc. Polyethylene has improved over time with the development of highly crosslinked polyethylene. Further improvements can be made by reinforcing it with vitamin E or multiwalled carbon nanotubes and by performing a surface modification with a biomembrane. Surface modifications with titanium nitride or titanium niobium nitride are implemented to try to improve the metal bearings. The advance to the fourth generation ceramics has shown relatively promising results, even in young patients. Nevertheless, further improvement is required to reduce fragility and squeaking. Alternative materials like diamond coatings on surfaces, carbon based composite materials, oxidized zirconium, silicon nitride, and sapphire are being sought. However, long-term studies are necessary to confirm the efficacy of these surfaces after enhancements

  15. Future bearing surfaces in total hip arthroplasty.

    PubMed

    Chang, Jun-Dong

    2014-03-01

    One of the most important issues in the modern total hip arthroplasty (THA) is the bearing surface. Extensive research on bearing surfaces is being conducted to seek an ideal bearing surface for THA. The ideal bearing surface for THA should have superior wear characteristics and should be durable, bio-inert, cost-effective, and easy to implant. However, bearing surfaces that are currently being implemented do not completely fulfill these requirements, especially for young individuals for whom implant longevity is paramount. Even though various new bearing surfaces have been investigated, research is still ongoing, and only short-term results have been reported from clinical trials. Future bearing surfaces can be developed in the following ways: (1) change in design, (2) further improvement of polyethylene, (3) surface modification of the metal, (4) improvement in the ceramic, and (5) use of alternative, new materials. One way to reduce wear and impingement in THA is to make changes in its design by using a large femoral head, a monobloc metal shell with preassembled ceramic liner, dual mobility cups, a combination of different bearing surfaces, etc. Polyethylene has improved over time with the development of highly crosslinked polyethylene. Further improvements can be made by reinforcing it with vitamin E or multiwalled carbon nanotubes and by performing a surface modification with a biomembrane. Surface modifications with titanium nitride or titanium niobium nitride are implemented to try to improve the metal bearings. The advance to the fourth generation ceramics has shown relatively promising results, even in young patients. Nevertheless, further improvement is required to reduce fragility and squeaking. Alternative materials like diamond coatings on surfaces, carbon based composite materials, oxidized zirconium, silicon nitride, and sapphire are being sought. However, long-term studies are necessary to confirm the efficacy of these surfaces after enhancements

  16. 17 CFR 240.12g5-2 - Definition of “total assets”.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... under this section and prepared in accordance with the pertinent provisions of Regulation S-X (17 CFR... “total assets”. For the purpose of section 12(g)(1) of the Act, the term total assets shall mean the total assets as shown on the issuer's balance sheet or the balance sheet of the issuer and...

  17. Metallized Products

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Since the early 1960's, virtually all NASA spacecraft have used metallized films for a variety of purposes, principally thermal radiation insulation. King Seeley manufactures a broad line of industrial and consumer oriented metallized film, fabric, paper and foam in single layer sheets and multi-layer laminates. A few examples, commercialized by MPI Outdoor Safety Products, are the three ounce Thermos Emergency Blanket which reflects and retains up to 80 percent of the user's body heat helping prevent post accident shock or keeping a person warm for hours under emergency cold weather conditions.

  18. Surface protected lithium-metal-oxide electrodes

    DOEpatents

    Thackeray, Michael M.; Kang, Sun-Ho

    2016-04-05

    A lithium-metal-oxide positive electrode having a layered or spinel structure for a non-aqueous lithium electrochemical cell and battery is disclosed comprising electrode particles that are protected at the surface from undesirable effects, such as electrolyte oxidation, oxygen loss or dissolution by one or more lithium-metal-polyanionic compounds, such as a lithium-metal-phosphate or a lithium-metal-silicate material that can act as a solid electrolyte at or above the operating potential of the lithium-metal-oxide electrode. The surface protection significantly enhances the surface stability, rate capability and cycling stability of the lithium-metal-oxide electrodes, particularly when charged to high potentials.

  19. Scheme for total quantum teleportation

    PubMed

    DelRe; Crosignani; Di Porto P

    2000-03-27

    We address the issue of totally teleporting the quantum state of an external particle, as opposed to studies on partial teleportation of external single-particle states, total teleportation of coherent states and encoded single-particle states, and intramolecular teleportation of nuclear spin states. We find a set of commuting observables whose measurement directly projects onto the Bell basis and discuss a possible experiment, based on two-photon absorption, allowing, for the first time, total teleportation of the state of a single external photon through a direct projective measurement. PMID:11018993

  20. 7 CFR 63.1 - Act.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) NATIONAL SHEEP INDUSTRY IMPROVEMENT CENTER... Development Act, 7 U.S.C. 2008j, as amended by section 11009 of the Food, Conservation, and Energy Act of...

  1. 7 CFR 63.1 - Act.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) NATIONAL SHEEP INDUSTRY IMPROVEMENT CENTER... Development Act, 7 U.S.C. 2008j, as amended by section 11009 of the Food, Conservation, and Energy Act of...

  2. 7 CFR 63.1 - Act.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) NATIONAL SHEEP INDUSTRY IMPROVEMENT CENTER... Development Act, 7 U.S.C. 2008j, as amended by section 11009 of the Food, Conservation, and Energy Act of...

  3. 7 CFR 63.1 - Act.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) NATIONAL SHEEP INDUSTRY IMPROVEMENT CENTER... Development Act, 7 U.S.C. 2008j, as amended by section 11009 of the Food, Conservation, and Energy Act of...

  4. The Privacy Act of 1974.

    ERIC Educational Resources Information Center

    O'Reilly, James T.

    This report describes the possible impact of the comprehensive Privacy Act of 1974, which went into effect on 27 September 1975. Specifically, the implications of the act for limitation of disclosure, federal information collection, individual access, private suits; criminal provisions; and exceptions to the provisions of the law are detailed. In…

  5. Nurse Reinvestment Act. Public Law.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC.

    This document contains the text of the Nurse Reinvestment Act, which amends the Public Health Service Act to address the increasing shortage of registered nurses by instituting a series of policies to improve nurse recruitment and nurse retention. Title I details two initiatives to boost recruitment of nurses. The first initiative includes the…

  6. 76 FR 59073 - Privacy Act

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-23

    ... From the Federal Register Online via the Government Publishing Office CENTRAL INTELLIGENCE AGENCY 32 CFR Part 1901 Privacy Act AGENCY: Central Intelligence Agency. ACTION: Proposed rule. SUMMARY: Consistent with the Privacy Act (PA), the Central Intelligence Agency (CIA) has undertaken and completed...

  7. Biomass Program Recovery Act Factsheet

    SciTech Connect

    2010-03-01

    The Biomass Program has awarded about $718 million in American Recovery and Reinvestment Act (Recovery Act) funds. The projects the Program is supporting are intended to: Accelerate advanced biofuels research, development, and demonstration; Speed the deployment and commercialization of advanced biofuels and bioproducts; Further the U.S. bioindustry through market transformation and creating or saving a range of jobs.

  8. Education Leaders Applaud ATTAIN Act

    ERIC Educational Resources Information Center

    Curriculum Review, 2007

    2007-01-01

    This article talks about Achievement Through Technology and Innovation (ATTAIN) Act, a bill introduced by Senators Bingaman (D-NM), Burr (R-NC), and Murray (D-WA) and applauded by a coalition of education and industry groups. The proposed ATTAIN Act is similar to its companion in the House (HR 2449), and builds upon the Enhancing Education Through…

  9. Act of 13 March 1989.

    PubMed

    1989-01-01

    This document contains the text of a 1989 Act of Utah prohibiting surrogate parenthood agreements of any type. Surrogate mothers are the legal mothers of their children, and their husbands are the legal fathers. This Act has no impact on adoption laws. PMID:12344464

  10. Implementing the Amended FOI Act.

    ERIC Educational Resources Information Center

    McClain, Wallis

    The Freedom of Information Act amendments, which became effective in February 1975, have so far yielded mixed results. This report provides an account of how different federal agencies are implementing this amended statute. Among the topics discussed are modifications of the original 1966 Freedom of Information Act, which were made in the attempt…

  11. Acting to let someone die.

    PubMed

    McGee, Andrew

    2015-02-01

    This paper examines the recent prominent view in medical ethics that withdrawing life-sustaining treatment (LST) is an act of killing. I trace this view to the rejection of the traditional claim that withdrawing LST is an omission rather than an act. Although that traditional claim is not as problematic as this recent prominent view suggests, my main claim is that even if we accepted that withdrawing LST should be classified as an act rather than as an omission, it could still be classified as letting die rather than killing. Even though omissions are contrasted with acts, letting die need not be, for one can let die by means of acts. The remainder of the paper is devoted to establishing this claim and addresses certain objections to it. PMID:24320715

  12. Graphene-metal interfaces for biosensors devices

    NASA Astrophysics Data System (ADS)

    Zuppella, Paola; Gerlin, Francesca; Bacco, Davide; Corso, Alain J.; Tessarolo, Enrico; Nardello, Marco; Silvestrini, Simone; Maggini, Michele; Pelizzo, Maria G.

    2015-08-01

    Graphene-metals interfaces are investigated in many subject areas both applicative and speculative. The interest mainly stems from the possibility for CVD synthesis of large area graphene on metals. In this case the metal acts as a catalyst for complete dehydrogenetaion of hydrocarbon precursors that leaves carbon behind at the surface. Such bilayer are also very appealing for surface plasmon resonance devices, since graphene acts both as a protective layer and biorecognition element. Several pairs of graphene-metal interfaces have been studied in terms of SPR performance and physicalchemical properties at the interface. With regard to this last aspect, NEXAFS spectroscopy is a powerful method to study single-, double-, and few- layers graphene and to illustrate any evolution of the electronic states.

  13. Remobilization of trace metals from contaminated marine sediment in a simulated dynamic environment.

    PubMed

    Xu, Weihai; Li, Xiangdong; Wai, Onyx W H; Huang, Weilin; Yan, Wen

    2015-12-01

    In this study, release and redistribution of sediment bound trace metals due to resuspension were investigated by a lid-driven elongated annular flume (LEAF). The total suspended particulate matters (SPMs) increased significantly in quantity with the raised resuspension energies and varied distinctively in particle size and mineral composition. Except for Cu, Ni, Cd, Pb, and Zn showed an increase in dissolved phase as the resuspension energy increased. Relatively low Cu was observed in dissolved phase whereas it owned the highest original concentration in the sediment. This is primarily due to the very low solubility of Cu sulfide. In comparison to sediment, all metals were evidently enriched in SPMs which primarily contributed to the much more fine particles (silt/clay fraction) contained in the SPMs. Metals enrichment followed the Irving-Williams order of complex stability. However, metals content varied indistinctively in the SPMs among the three selected resuspension levels. The distribution coefficients (K d) exhibited opposite trend with the increasing resuspension level with the exception of Cu. It indicated that physical and chemical characters of sediment such as grain composition, Fe/Mn, and organic matter content may also act as major factors in the release of metals and control their phase distribution in the water column. PMID:26289335

  14. Electronic property and reactivity of (hydroperoxo)metal compounds.

    PubMed

    Nishida, Y; Nishino, S

    2001-01-01

    DFT calculations were done for the (hydroperoxo)metal complexes with eta1-coordination mode, where metal ions are Fe(III), Al(III), Cu(II) and Zn(II). Results shows that 1) the electron density at the two oxygen atoms of the hydroperoxide ion is highly dependent on the angle O-O-H in M-OOH species and the difference in electron density between the two oxygen atoms reaches a maximum at the angle O-O-H = 180 degrees, 2) total electron density at the two oxygen atoms of the peroxide ion increases by approach of methane to the (hydroperoxo)metal species in the cases of Fe(III) and Cu(II); on the other hand, significant decrease of the electron density on peroxide oxygen atoms was observed for the cases of Al(III) and Zn(II) compounds. These findings suggest that the (hydroperoxo)metal species acts as an electrophile in the former cases (M = Fe(III), Cu(II)) and as a nucleophile for the latter two compounds (M = Zn(II), Al(III)). The electrophilicity observed for the Fe(III) and Cu(II) complexes is attributed to the presence of unoccupied- or half-filled d-orbitals interacting with the hydroperoxide ion. 3) Two oxygen atoms of the (hydroperoxo)-compounds of Fe(III) and Cu(II) complexes exhibit quite different reactivity toward the substrate, such as methane. When methane approaches the oxygen atom which is coordinated to a metal ion, a strong decrease of electron density at the methane carbon atom occurs with concomitant increase of electron density at the peroxide oxygen atoms inducing its heterolytic O-O cleavage. When methane approaches the terminal oxygen atom, an oxidative coupling reaction occurs between peroxide ion and methane; at first a nucleophilic attack by the terminal electron-rich oxygen atom occurs at the carbon atom to induce C-O bond formation, and a subsequent oxidative electron transfer proceeds from substrate to the metal-peroxide species yielding CH3-OOH, CH3OH, or other oxidized products. These results clearly demonstrate that the (hydroperoxo)-metal

  15. Fracture After Total Hip Replacement

    MedlinePlus

    ... er Total Hip Replacement cont. • Dislocation • Limb length inequality • Poor fracture healing • Repeat fracture • Lack of in- ... Surgeons (AAOS). To learn more about your orthopaedic health, please visit orthoinfo.org. Page ( 5 ) AAOS does ...

  16. A Choir for Total Communication.

    ERIC Educational Resources Information Center

    Knapp, Ruth Ann

    1980-01-01

    The Total Communication Choir of the Saginaw, Michigan, public schools integrates deaf and hearing elementary and junior high students in music performance. All students both sign and sing. Methods used to instruct the choir are described. (SJL)

  17. March 8 Solar Eclipse Totality

    NASA Video Gallery

    The moon passes in front of the sun, creating a total solar eclipse visible in parts of Southeast Asia. This video. taken from a live broadcast from the Exploratorium Science Center, shows the peri...

  18. Pyodermatitis vegetans after total colectomy

    PubMed Central

    Uzunçakmak, Tuğba Kevser; Akdeniz, Necmettin; Karadağ, Ayşe Serap; Çobanoğlu, Bengü

    2015-01-01

    Pyostomatitis–pyodermatitis vegetans (PPV) is a rare dermatological manifestation of inflammatory bowel disease, characterized by erythematous, vesiculopustular, exudative, annular, and/or vegetating plaques over the intertriginous regions that may precede or appear at the same time as the mucosal lesions. Systemic corticosteroids, dapsone, sulfasalazine, azathioprine, cyclosporine, and subtotal/total colectomy are the most common treatment options. A 16-year-old male patient presented to our outpatient clinic with a four months history of thickly crusted erosions on his trunk, back, and lower extremity. He had ulcerative colitis for four years and total colectomy was done seven months ago. Clinical and histopathological examination of his lesions were consistent with pyostomatitis vegetans. Although subtotal/total colectomy has been reported as a treatment option for PPV, lesions reappeared three months after total colectomy in our patient. PMID:26904460

  19. Total synthesis of (-)-spinosyn A.

    PubMed

    Mergott, Dustin J; Frank, Scott A; Roush, William R

    2004-08-17

    A convergent, highly stereoselective total synthesis of (-)-spinosyn A (1) is described. Key features of the synthesis include the transannular Diels-Alder reaction of macrocyclic pentaene 11 and the transannular Morita-Baylis-Hillman cyclization of 12 that generates tetracycle 26. The total synthesis of (-)-spinosyn A was completed by a sequence involving the highly beta-selective glycosidation reaction of 13 and glycosyl imidate 30. PMID:15173590

  20. 76 FR 14439 - No FEAR Act Notice

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-16

    ... TRANSPARENCY BOARD No FEAR Act Notice AGENCY: Recovery Accountability and Transparency Board. ACTION: Notice... and Retaliation Act (No FEAR Act or Act), as implemented by Office of Personnel Management (OPM... No FEAR Act. See Public Law 107-174, codified at 5 U.S.C. 2301 note. One purpose of the Act is...

  1. METAL COMPOSITIONS

    DOEpatents

    Seybolt, A.U.

    1959-02-01

    Alloys of uranium which are strong, hard, and machinable are presented, These alloys of uranium contain bctween 0.1 to 5.0% by weight of at least one noble metal such as rhodium, palladium, and gold. The alloys may be heat treated to obtain a product with iniproved tensile and compression strengths,

  2. Heavy Metal.

    ERIC Educational Resources Information Center

    Shoemaker, W. Lee

    1998-01-01

    Discusses the advantages, both functional and economic, of using a standing-seam metal roof in both new roof installations and reroofing projects of educational facilities. Structural versus non-structural standing-seam roofs are described as are the types of insulation that can be added and roof finishes used. (GR)

  3. Noble metal ionic catalysts.

    PubMed

    Hegde, M S; Madras, Giridhar; Patil, K C

    2009-06-16

    Because of growing environmental concerns and increasingly stringent regulations governing auto emissions, new more efficient exhaust catalysts are needed to reduce the amount of pollutants released from internal combustion engines. To accomplish this goal, the major pollutants in exhaust-CO, NO(x), and unburned hydrocarbons-need to be fully converted to CO(2), N(2), and H(2)O. Most exhaust catalysts contain nanocrystalline noble metals (Pt, Pd, Rh) dispersed on oxide supports such as Al(2)O(3) or SiO(2) promoted by CeO(2). However, in conventional catalysts, only the surface atoms of the noble metal particles serve as adsorption sites, and even in 4-6 nm metal particles, only 1/4 to 1/5 of the total noble metal atoms are utilized for catalytic conversion. The complete dispersion of noble metals can be achieved only as ions within an oxide support. In this Account, we describe a novel solution to this dispersion problem: a new solution combustion method for synthesizing dispersed noble metal ionic catalysts. We have synthesized nanocrystalline, single-phase Ce(1-x)M(x)O(2-delta) and Ce(1-x-y)Ti(y)M(x)O(2-delta) (M = Pt, Pd, Rh; x = 0.01-0.02, delta approximately x, y = 0.15-0.25) oxides in fluorite structure. In these oxide catalysts, Pt(2+), Pd(2+), or Rh(3+) ions are substituted only to the extent of 1-2% of Ce(4+) ion. Lower-valent noble metal ion substitution in CeO(2) creates oxygen vacancies. Reducing molecules (CO, H(2), NH(3)) are adsorbed onto electron-deficient noble metal ions, while oxidizing (O(2), NO) molecules are absorbed onto electron-rich oxide ion vacancy sites. The rates of CO and hydrocarbon oxidation and NO(x) reduction (with >80% N(2) selectivity) are 15-30 times higher in the presence of these ionic catalysts than when the same amount of noble metal loaded on an oxide support is used. Catalysts with palladium ion dispersed in CeO(2) or Ce(1-x)Ti(x)O(2) were far superior to Pt or Rh ionic catalysts. Therefore, we have demonstrated that the

  4. Trace metals in marine sediments of Kuwait

    SciTech Connect

    Anderlini, V.C.; Mohammad, O.S.; Zarba, M.A.; Fowler, S.W.; Miramand, P.

    1982-01-01

    The report presents the results of analyses for ten trace metals (Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn) in marine surface sediments from Kuwait and discusses the effect of grain size and total organic content on the observed concentrations of these metals. (JMT)

  5. Composite metal membrane

    DOEpatents

    Peachey, Nathaniel M.; Dye, Robert C.; Snow, Ronny C.; Birdsell, Stephan A.

    1998-01-01

    A composite metal membrane including a first metal layer of Group IVB met or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof is provided together with a process for the recovery of hydrogen from a gaseous mixture including contacting a hydrogen-containing gaseous mixture with a first side of a nonporous composite metal membrane including a first metal of Group IVB metals or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof, and, separating hydrogen from a second side of the nonporous composite metal membrane.

  6. Composite metal membrane

    DOEpatents

    Peachey, N.M.; Dye, R.C.; Snow, R.C.; Birdsell, S.A.

    1998-04-14

    A composite metal membrane including a first metal layer of Group IVB met or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof is provided together with a process for the recovery of hydrogen from a gaseous mixture including contacting a hydrogen-containing gaseous mixture with a first side of a nonporous composite metal membrane including a first metal of Group IVB metals or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof, and, separating hydrogen from a second side of the nonporous composite metal membrane.

  7. Assessment & Commitment Tracking System (ACTS)

    2004-12-20

    The ACTS computer code provides a centralized tool for planning and scheduling assessments, tracking and managing actions associated with assessments or that result from an event or condition, and "mining" data for reporting and analyzing information for improving performance. The ACTS application is designed to work with the MS SQL database management system. All database interfaces are written in SQL. The following software is used to develop and support the ACTS application: Cold Fusion HTMLmore » JavaScript Quest TOAD Microsoft Visual Source Safe (VSS) HTML Mailer for sending email Microsoft SQL Microsoft Internet Information Server« less

  8. Assessment & Commitment Tracking System (ACTS)

    SciTech Connect

    Bryant, Robert A.; Childs, Teresa A.; Miller, Michael A.; Sellars, Kevin J.

    2004-12-20

    The ACTS computer code provides a centralized tool for planning and scheduling assessments, tracking and managing actions associated with assessments or that result from an event or condition, and "mining" data for reporting and analyzing information for improving performance. The ACTS application is designed to work with the MS SQL database management system. All database interfaces are written in SQL. The following software is used to develop and support the ACTS application: Cold Fusion HTML JavaScript Quest TOAD Microsoft Visual Source Safe (VSS) HTML Mailer for sending email Microsoft SQL Microsoft Internet Information Server

  9. ACTS and OLYMPUS propagation experiments

    NASA Technical Reports Server (NTRS)

    Bostian, Charles W.; Baker, Kenneth R.

    1988-01-01

    The OLYMPUS and ACTS satellites both provide opportunities for 10 to 30 GHz propagation measurements. The spacecraft are sufficiently alike that OLYMPUS can be used to test some prototype ACTS equipment and experiments. Data are particularly needed on short term signal behavior and in support of uplink power control and adaptive forward error correction (FEC) techniques. The Virginia Tech Satellite Communications Group has proposed a set of OLYMPUS experiments including attenuation and fade rate measurements, data communications, uplink power control, rain scatter interference, and small-scale site diversity operation. A digital signal processing receiver for the OLYMPUS and ACTS beacon signals is being developed.

  10. Total Irradiance Monitor Observations of Total Solar Irradiance

    NASA Astrophysics Data System (ADS)

    Kopp, G.

    2007-12-01

    The Total Irradiance Monitor (TIM) is the most recent instrument launched to measure total solar irradiance (TSI) from space. This electrical substitution radiometer has on-orbit degradation tracking to provide very stable long- term measurements of the net solar radiation incident on the Earth, and the instrument continues the 29-year record of this natural driver of Earth climate. Currently flying on the SOlar Radiation and Climate Experiment (SORCE), the TIM has been providing stable, low-noise, and accurate measurements of TSI since early 2003. The TIM will next be flying on NASA's Glory climate mission and is one instrument of the Total Solar Irradiance Sensor (TSIS) selected to continue this important climate record well into the future. The SORCE/TIM has created renewed interest in the TSI absolute value and has acquired the first measurements of the total radiant energy released by large solar flares. Improvements in ground-based calibrations starting with the Glory/TIM will establish traceability linking current to upcoming measurements, solidifying the existing TSI climate data record in the undesirable event of a future data gap.

  11. Total Quality Management Is Total at Fox Valley Technical College.

    ERIC Educational Resources Information Center

    Tyler, Carol R.

    1993-01-01

    At Fox Valley Technical College (Wisconsin), application of Total Quality Management (TQM) brought positive outcomes and other effects. Areas in which TQM was used are considered, including admissions, employee safety, customer focus, policy formation, management performance appraisal, student services, creation of a self-managing class, TQM for…

  12. Total body water and total body potassium in anorexia nervosa

    SciTech Connect

    Dempsey, D.T.; Crosby, L.O.; Lusk, E.; Oberlander, J.L.; Pertschuk, M.J.; Mullen, J.L.

    1984-08-01

    In the ill hospitalized patient with clinically relevant malnutrition, there is a measurable decrease in the ratio of the total body potassium to total body water (TBK/TBW) and a detectable increase in the ratio of total exchangeable sodium to total exchangeable potassium (Nae/Ke). To evaluate body composition analyses in anorexia nervosa patients with chronic uncomplicated semistarvation, TBK and TBW were measured by whole body K40 counting and deuterium oxide dilution in 10 females with stable anorexia nervosa and 10 age-matched female controls. The ratio of TBK/TBW was significantly (p less than 0.05) higher in anorexia nervosa patients than controls. The close inverse correlation found in published studies between TBK/TBW and Nae/Ke together with our results suggest that in anorexia nervosa, Nae/Ke may be low or normal. A decreased TBK/TBW is not a good indicator of malnutrition in the anorexia nervosa patient. The use of a decreased TBK/TBW ratio or an elevated Nae/Ke ratio as a definition of malnutrition may result in inappropriate nutritional management in the patient with severe nonstressed chronic semistarvation.

  13. Pollution prevention in the fabricated metals products industry

    SciTech Connect

    Denny, D.; Frewerd, B.; Pava, T.H.; Appley, E.

    1995-09-01

    The US metal fabrication industry is an essential part of both domestic and international economies and plays a key support role in the appliance, automotive, defense, electronics, furniture, and other assembly industries. Identified as Standard Industrial Classification Code (SIC Code) 34, the industry processes and manufacturers a wide range of metal components including cans, cutlery, hand tools, general hardware, ordnance, forgings, stampings, and structural metal products. The industry`s environmental compliance problems arise from increasingly restrictive discharge limitations and from the product phaseout of ozone-depleting chemicals (ODCs) as mandated in the 1990 Clean Air Act Amendments. Hazardous raw materials in some metal fabrication operations are regulated under the Occupational Safety and Health Act (OSHA). Some facility discharges are regulated by the Resource Conservation and Recovery Act (RCRA). The major pollutants of concern are volatile organic compounds (VOCs), ozone-depleting compounds (ODCs), hazardous air pollutants, heavy metals, acids, and oils.

  14. Advances in total scattering analysis

    SciTech Connect

    Proffen, Thomas E; Kim, Hyunjeong

    2008-01-01

    In recent years the analysis of the total scattering pattern has become an invaluable tool to study disordered crystalline and nanocrystalline materials. Traditional crystallographic structure determination is based on Bragg intensities and yields the long range average atomic structure. By including diffuse scattering into the analysis, the local and medium range atomic structure can be unravelled. Here we give an overview of recent experimental advances, using X-rays as well as neutron scattering as well as current trends in modelling of total scattering data.

  15. Total Ozone Prediction: Stratospheric Dynamics

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Kawa, S. Ramdy; Douglass, Anne R.

    2003-01-01

    The correct prediction of total ozone as a function of latitude and season is extremely important for global models. This exercise tests the ability of a particular model to simulate ozone. The ozone production (P) and loss (L) will be specified from a well- established global model and will be used in all GCMs for subsequent prediction of ozone. This is the "B-3 Constrained Run" from M&MII. The exercise mostly tests a model stratospheric dynamics in the prediction of total ozone. The GCM predictions will be compared and contrasted with TOMS measurements.

  16. Total eclipses of the sun.

    PubMed

    Zirker, J B

    1980-12-19

    Total eclipses of the sun offer research opportunities in a variety of sciences. Some of the advances in solar physics resulting from eclipse observations are discussed. Experiments at the total eclipse of 16 February 1980 in India are also described. These included a test of general relativity, studies in coronal physics, investigations of solar prominences, diameter measurements, a search for interplanetary dust, a study of the gravity waves in the earth's atmosphere, and experiments on the biological effects on animals and humans. PMID:17817829

  17. The Metallicity of Giant Planets

    NASA Astrophysics Data System (ADS)

    Thorngren, Daniel P.; Fortney, Jonathan

    2015-12-01

    Unique clues about the formation processes of giant planets can be found in their bulk compositions. Transiting planets provide us with bulk density determinations that can then be compared to models of planetary structure and evolution, to deduce planet bulk metallicities. At a given mass, denser planets have a higher mass fraction of metals. However, the unknown hot Jupiter "radius inflation" mechanism leads to under-dense planets that severely biases this work. Here we look at cooler transiting gas giants (Teff < 1000 K), which do not exhibit the radius inflation effect seen in their warmer cousins. We identified 40 such planets between 20 M_Earth and 20 M_Jup from the literature and used evolution models to determine their bulk heavy-element ("metal") mass. Several important trends are apparent. We see that all planets have at least ~10 M_Earth of metals, and that the mass of metal correlates strongly with the total mass of the planet. The heavy-element mass goes as the square root of the total mass. Both findings are consistent with the core accretion model. We also examined the effect of the parent star metallicity [Fe/H], finding that planets around high-metallicity stars are more likely to have large amounts of metal, but the relation appears weaker than previous studies with smaller sample sizes had suggested. We also looked for connections between bulk composition and planetary orbital parameters and stellar parameters, but saw no pattern, which is also an important result. This work can be directly compared to current and future outputs from planet formation models, including population synthesis.

  18. Model Occupational Therapy Practice Act

    ERIC Educational Resources Information Center

    American Journal of Occupational Therapy, 1975

    1975-01-01

    The Model Occupational Therapy Practice Act has been assembled by the Government Affairs Department, American Occupational Therapy Association, for use as a guide for affiliate organizations concerned with developing legislation to regulate the practice of occupational therapy. (Author/JA)

  19. 78 FR 73466 - Privacy Act

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-06

    ... or qualifications for Federal civilian employment, military service, Federal contracts or access to... From the Federal Register Online via the Government Publishing Office OVERSEAS PRIVATE INVESTMENT CORPORATION 22 CFR Part 707 Privacy Act AGENCY: Overseas Private Investment Corporation. ACTION: Notice...

  20. Prelinguistic Vocalizations Distinguish Pointing Acts

    ERIC Educational Resources Information Center

    Grunloh, Thomas; Liszkowski, Ulf

    2015-01-01

    The current study investigated whether point-accompanying characteristics, like vocalizations and hand shape, differentiate infants' underlying motives of prelinguistic pointing. We elicited imperative (requestive) and declarative (expressive and informative) pointing acts in experimentally controlled situations, and analyzed accompanying…

  1. Monitoring EERE's Recovery Act Portfolio

    SciTech Connect

    2011-01-01

    Performance monitoring of Recovery Act projects within EERE has been an ongoing effort. Project recipients have been reporting technical and financial progress to project officers on a quarterly basis.

  2. Spatial distribution of metals in smelter-impacted soils of woody habitats: influence of landscape and soil properties, and risk for wildlife.

    PubMed

    Fritsch, Clémentine; Giraudoux, Patrick; Cœurdassier, Michaël; Douay, Francis; Raoul, Francis; Pruvot, Christelle; Waterlot, Christophe; de Vaufleury, Annette; Scheifler, Renaud

    2010-09-01

    The spatial distribution of total and CaCl(2)-extracted Cd, Pb and Zn concentrations in smelter-impacted soils was investigated over a polluted site (40 km(2)) in Northern France. The study was conducted on 262 soils sampled in woody habitats. Total and extracted concentrations of trace metals (TMs) rose up to 2402 and 59.5 mg kg(-1) for Cd, 41 960 and 13.7 mg kg(-1) for Pb, 38 760 and 143.0 mg kg(-1) for Zn, respectively. The spatial dependence of both total and extracted concentrations showed a high spatial auto-correlation and ordinary kriging was used to predict soil concentrations. Investigating which variables influenced metal concentrations and their spatial distribution, we found that total concentrations mostly depended on the distance from the smelter, the wind and the organic carbon, while extracted concentrations were mainly modulated by the pH. Conditionally to those variables, other soil properties and landscape characteristics influenced both total and extracted concentrations. We conclude that total and extracted TM concentrations are governed by different processes which act at various spatial ranges: total concentrations are mainly related to input and retention of metals (large scale) whereas extracted concentrations were mainly explained by factors controlling metal solubility in soils (local scale). Spatial distributions of total and extracted TMs differed over the area, which should be considered for risk assessment. Maps of risk based on the US EPA's Eco-SSLs (for plants, invertebrates and vertebrates) were realized, showing that wildlife may be at risk but that the relevance of Eco-SSL values is questionable. PMID:20673957

  3. Liquid metal ion source and alloy

    DOEpatents

    Clark, Jr., William M.; Utlaut, Mark W.; Behrens, Robert G.; Szklarz, Eugene G.; Storms, Edmund K.; Santandrea, Robert P.; Swanson, Lynwood W.

    1988-10-04

    A liquid metal ion source and alloy, wherein the species to be emitted from the ion source is contained in a congruently vaporizing alloy. In one embodiment, the liquid metal ion source acts as a source of arsenic, and in a source alloy the arsenic is combined with palladium, preferably in a liquid alloy having a range of compositions from about 24 to about 33 atomic percent arsenic. Such an alloy may be readily prepared by a combustion synthesis technique. Liquid metal ion sources thus prepared produce arsenic ions for implantation, have long lifetimes, and are highly stable in operation.

  4. 75 FR 29 - Privacy Act, Government in the Sunshine Act, Freedom of Information Act (“FOIA”), and Federal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-04

    ... the Sunshine Act, Freedom of Information Act (``FOIA''), and Federal Election Campaign Act (``FECA... of Information Act of 1966, as amended, 5 U.S.C. 552, and the Federal Election Campaign Act (``FECA... requirements. 11 CFR Part 104 Campaign funds, Political committees and parties, Reporting and...

  5. The Academic Senate Perspective on the Personal Responsibility and Work Opportunity Reconciliation Act of 1996 (HR 3734, The Welfare Reform Act).

    ERIC Educational Resources Information Center

    Academic Senate for California Community Colleges, Sacramento.

    The Welfare Reform Act of 1996, with its emphasis on mandatory work, will have a serious impact on communities throughout California. In 1995-96, a total of 760,000 people received Aid to Families with Dependent Children (AFDC), while 139,713 of these were community college students. To respond to the Act, the California Community Colleges should…

  6. Magnetic, electronic, and vibrational properties of metal and fluorinated metal phthalocyanines

    NASA Astrophysics Data System (ADS)

    Arillo-Flores, O. I.; Fadlallah, M. M.; Schuster, C.; Eckern, U.; Romero, A. H.

    2013-04-01

    The magnetic and electronic properties of metal phthalocyanines (MPc) and fluorinated metal phthalocyanines (F16MPc) are studied by means of spin density functional theory (SDFT). Several metals (M) such as Ca, all first d-row transition metals, and Ag are investigated. By considering different open shell transition metals it is possible to tune the electronic properties of MPc, in particular the electronic molecular gap and total magnetic moment. Besides determining the structural and electronic properties of MPc and F16MPc, the vibrational modes of the ScPc-ZnPc series have been studied.

  7. Gap Balanced Total Knee Arthroplasty

    MedlinePlus

    Gap Balanced Total Knee Arthroplasty – SIGMA® with AOX™ You must have Javascript enabled in your web browser. View Program Transcript Click Here to view the OR-Live, Inc. Privacy Policy and Legal Notice © 2010 OR-Live, Inc. All rights reserved.

  8. Energy Planning: A Total Concept.

    ERIC Educational Resources Information Center

    Hall, Stephen S. J.

    1975-01-01

    Harvard's energy conservation plan is presented in detail with the hope that it will suggest practical, cost-effective energy-saving ideas to other institutions, and to dispel frequently-expressed fears concerning the feasibility and acceptance problems of this type of program. The total energy plan incorporates numerous specific elements that…

  9. The Total Cost of Ownership.

    ERIC Educational Resources Information Center

    Day, C. William

    2000-01-01

    Examines what Total Cost of Ownership is regarding the purchase of technological resources for schools and the major expenses that are likely to occur after technological hardware and software have been installed. A list of best practices that can reduce costs approximately 15 percent and a checklist for technology budgeting are provided. (GR)

  10. Total Quality Management for Schools.

    ERIC Educational Resources Information Center

    Greenwood, Malcolm S.; Gaunt, Helen J.

    Education in the United Kingdom has been shaped by the advent of local school management and the rapid growth of grant-maintained schools. Total Quality Management (TQM) offers a new way of looking at management principles and structures by identifying the needs of both internal and external customers. This book applies principles of TQM…

  11. Total Quality Management in Education.

    ERIC Educational Resources Information Center

    Johnson, James H.

    1993-01-01

    Ways to apply the concepts and processes of Total Quality Management (TQM) to education are discussed in this document. Following the introduction and the preface, chapter 1 provides a historical overview and describes the four cornerstones of TQM--an understanding of systems, psychology, knowledge, and statistics. Chapter 2 describes some of the…

  12. Total Synthesis of Amphirionin-4.

    PubMed

    Holmes, Michael; Kwon, Daniel; Taron, Matthew; Britton, Robert

    2015-08-01

    The first total synthesis of amphirionin-4 has been achieved using a combination of cross-coupling strategies to access the polyene side chain and a chlorohydrin-based approach to construct the tetrahydrofuranol core. The remote C9-stereocenter was introduced through a Nozaki-Hiyama-Kishi coupling that proceeded with remote stereoinduction. PMID:26172382

  13. Endoscopic Transaxillary Near Total Thyroidectomy

    PubMed Central

    Ejeh, Ijeoma Acholonu; Speights, Fredne; Rashid, Qammar N.; Ideis, Mustafa

    2006-01-01

    Background: Since first reported in 1996, endoscopic minimally invasive surgery of the cervical region has been shown to be safe and effective in the treatment of benign thyroid and parathyroid disease. The endoscopic transaxillary technique uses a remote lateral approach to the thyroid gland. Because of the perceived difficulty in accessing the contralateral anatomy of the thyroid gland, this technique has typically been reserved for patients with unilateral disease. Objectives: The present study examines the safety and feasibility of the transaxillary technique in dissecting and assessment of both thyroid lobes in performing near total thyroidectomy. Methods: Prior to this study we successfully performed endoscopic transaxillary thyroid lobectomy in 32 patients between August 2003 and August 2005. Technical feasibility in performing total thyroidectomy using this approach was accomplished first utilizing a porcine model followed by three human cadaver models prior to proceeding to human surgery. After IRB approval three female patients with histories of enlarging multinodular goiter were selected to undergo endoscopic near total thyroidectomy. Results: The average operative time for all models was 142 minutes (range 57–327 min). The three patients in this study had clinically enlarging multinodular goiters with an average size of 4 cm. The contralateral recurrent laryngeal nerve and parathyroid glands were identified in all cases. There was no post-operative bleeding, hoarseness or subcutaneous emphysema. Conclusion: Endoscopic transaxillary near total thyroidectomy is feasible and can be performed safely in human patients with bilateral thyroid disease. PMID:16882421

  14. The Total Synthesis of Neoamphimedine

    PubMed Central

    LaBarbera, Daniel V.; Bugni, Tim S.; Ireland, Chris M.

    2008-01-01

    Neoamphimedine, a Pyridoacridine alkaloid from Xestospongia sp., is a potent antitumor agent both in vitro and in vivo. Neoamphimedine can efficiently induce topoisomerase II mediated catenation of plasmid DNA in vitro, and is the only member of more than one hundred pyridoacridines thus far to have this mechanism of action. Herein we report the first total synthesis of Neoamphimedine. PMID:17900144

  15. 50 CFR 648.161 - Bluefish Annual Catch Targets (ACTs).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE NORTHEASTERN UNITED STATES Management... commercial and recreational sector-specific ACTs shall be less than or equal to the fishery level ACL. The... uncertainty, consistent with paragraph (a) of this section. A total of 83 percent of the fishery-level...

  16. Higher Education Cooperation Act: Fiscal Year 1998 Grant Allocations.

    ERIC Educational Resources Information Center

    Illinois State Board of Higher Education, Springfield.

    This report describes fiscal year 1998 grant allocations made under the Illinois Higher Education Cooperation Act (HECA) to support programs and projects involving cooperation among higher education institutions. A total of $16.59 million was allocated. Projects recommended for grant funds include 3 new and 12 continuing interinstitutional…

  17. Silicon nanocrystal-noble metal hybrid nanoparticles.

    PubMed

    Sugimoto, H; Fujii, M; Imakita, K

    2016-06-01

    We report a novel and facile self-limiting synthesis route of silicon nanocrystal (Si NC)-based colloidally stable semiconductor-metal (gold, silver and platinum) hybrid nanoparticles (NPs). For the formation of hybrid NPs, we employ ligand-free colloidal Si NCs with heavily boron (B) and phosphorus (P) doped shells. By simply mixing B and P codoped colloidal Si NCs with metal salts, hybrid NPs consisting of metal cores and Si NC shells are spontaneously formed. We demonstrate the synthesis of highly uniform and size controllable hybrid NPs. It is shown that codoped Si NCs act as a reducing agent for metal salts and also as a protecting layer to stop metal NP growth. The process is thus self-limiting. The development of a variety of Si NC-based hybrid NPs is a promising first step for the design of biocompatible multifunctional NPs with broad material choices for biosensing, bioimaging and solar energy conversion. PMID:27121127

  18. Stress fracture of the proximal fibula after total knee arthroplasty.

    PubMed

    Vaish, Abhishek; Vaishya, Raju; Agarwal, Amit Kumar; Vijay, Vipul

    2016-01-01

    We report a rare case of proximal fibular fatigue fracture developing 14 years after total knee arthroplasty in a known case of rheumatoid arthritis. A valgus deformity of the knee can put abnormal stress on the upper fibula leading to its failure. We believe that, as the fibula acts as an important lateral strut, its disruption due to a fracture led to rapid progress of the valgus deformity of the knee in this patient. PMID:27107057

  19. 40 CFR 63.7507 - What are the health-based compliance alternatives for the hydrogen chloride (HCl) and total...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 14 2012-07-01 2011-07-01 true What are the health-based compliance alternatives for the hydrogen chloride (HCl) and total selected metals (TSM) standards? 63.7507 Section 63.7507... the hydrogen chloride (HCl) and total selected metals (TSM) standards? (a) As an alternative to...

  20. 40 CFR 63.7507 - What are the health-based compliance alternatives for the hydrogen chloride (HCl) and total...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 13 2011-07-01 2011-07-01 false What are the health-based compliance alternatives for the hydrogen chloride (HCl) and total selected metals (TSM) standards? 63.7507 Section 63.7507... the hydrogen chloride (HCl) and total selected metals (TSM) standards? (a) As an alternative to...

  1. 40 CFR 63.7507 - What are the health-based compliance alternatives for the hydrogen chloride (HCl) and total...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 13 2010-07-01 2010-07-01 false What are the health-based compliance alternatives for the hydrogen chloride (HCl) and total selected metals (TSM) standards? 63.7507 Section 63.7507... the hydrogen chloride (HCl) and total selected metals (TSM) standards? (a) As an alternative to...

  2. 7 CFR 33.1 - Act.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AUTHORITY OF THE EXPORT APPLE ACT Definitions § 33.1 Act. Act and Export Apple Act are synonymous and mean “An act to promote the foreign trade of the United States in apples to protect the reputation of American-grown apples in foreign markets, to prevent deception or misrepresentation as to the quality...

  3. 7 CFR 33.1 - Act.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AUTHORITY OF THE EXPORT APPLE ACT Definitions § 33.1 Act. Act and Export Apple Act are synonymous and mean “An act to promote the foreign trade of the United States in apples to protect the reputation of American-grown apples in foreign markets, to prevent deception or misrepresentation as to the quality...

  4. 7 CFR 33.1 - Act.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AUTHORITY OF THE EXPORT APPLE ACT Definitions § 33.1 Act. Act and Export Apple Act are synonymous and mean “An act to promote the foreign trade of the United States in apples to protect the reputation of American-grown apples in foreign markets, to prevent deception or misrepresentation as to the quality...

  5. 7 CFR 33.1 - Act.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AUTHORITY OF THE EXPORT APPLE ACT Definitions § 33.1 Act. Act and Export Apple Act are synonymous and mean “An act to promote the foreign trade of the United States in apples to protect the reputation of American-grown apples in foreign markets, to prevent deception or misrepresentation as to the quality...

  6. 7 CFR 33.1 - Act.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AUTHORITY OF THE EXPORT APPLE ACT Definitions § 33.1 Act. Act and Export Apple Act are synonymous and mean “An act to promote the foreign trade of the United States in apples to protect the reputation of American-grown apples in foreign markets, to prevent deception or misrepresentation as to the quality...

  7. 40 CFR 721.640 - Amine substituted metal salts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.640 Amine substituted metal salts. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified generically as amine substituted metal...

  8. 40 CFR 721.4594 - Substituted azo metal complex dye.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.4594 Substituted azo metal complex dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted azo metal...

  9. 40 CFR 721.10006 - Mixed metal oxide (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10006 Mixed metal oxide (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as mixed metal oxide (PMN...

  10. 40 CFR 721.10104 - Halophosphate mixed metal complex (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10104 Halophosphate mixed metal complex (generic). (a) Chemical... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halophosphate mixed metal...

  11. 40 CFR 721.2093 - Alkenyl carboxylate, metal salt (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.2093 Alkenyl carboxylate, metal salt (generic). (a) Chemical substance... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkenyl carboxylate, metal...

  12. 40 CFR 721.4596 - Diazo substituted carbomonocyclic metal complex.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... metal complex. 721.4596 Section 721.4596 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.4596 Diazo substituted carbomonocyclic metal complex. (a)...

  13. 40 CFR 721.4740 - Alkali metal nitrites.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in...

  14. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal alkyl...

  15. 40 CFR 721.5548 - Mixed metal oxide (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.5548 Mixed metal oxide (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a mixed metal oxide (PMN P-97-956)...

  16. Fate of biosolids trace metals in a dryland wheat agroecosystem

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biosolids land application for beneficial reuse applies varying amounts of trace metals to soils. Measuring plant-available or total soil metals is typically performed to ensure environmental protection, yet these techniques do not quantify which soil phases play important roles in terms of metal r...

  17. Total sternectomy for malignant disease.

    PubMed

    París, F; Blasco, E; Tarazona, V; Pastor, J; Zarza, A G; Padilla, J

    1980-09-01

    From 1972 to 1978, six total sternectomies for malignant disease of the sternum were carried out. The clinical data are summarized and the surgical technique is described. After sternectomy, the area of chest wall resection was repaired by suturing a sheet of silicone rubber to the edges of the defect and chest wall stability was assured by using one or two stainless steel struts. Finally the defect was covered with methylmethacrylate prepared and applied inthe operative field. The prosthetic material was shaped until curing by polymerization was complete. We discuss the advantages of this type of reconstruction, the technical details, the use of antibiotics, the surgical drainage, and the need for biopsy prior to carrying out a total sternectomy. PMID:7412352

  18. Formal total synthesis of platencin.

    PubMed

    Varseev, Georgy N; Maier, Martin E

    2009-01-01

    The right bicycle: A concise formal synthesis of platencin was based on an efficient oxygen-mediated palladium-catalyzed cycloalkenylation of 1 to form a bicyclo[3.2.1]octane, and a deoxygenative rearrangement of tosylhydrazone 2 to construct the bicyclo[2.2.2]octane 3. The total yield of the core structure 4 of platencin was 17.5% for 13 steps from a commercially available compound. Ts = p-toluenesulfonyl, TBS = tert-butyldimethylsilyl, Piv = pivaloyl. PMID:19353600

  19. A Total Synthesis of Paeoveitol.

    PubMed

    Xu, Lun; Liu, Fengyi; Xu, Li-Wen; Gao, Ziwei; Zhao, Yu-Ming

    2016-08-01

    A four-step total synthesis of paeoveitol (1), a recently disclosed norditerpene natural product from Paeonia vetchii, is reported. This highly concise synthetic route was guided by biosynthetic considerations and enabled by an unusual intermolecular ortho-quinone methide [4 + 2]-cycloaddition reaction, which proceeded with excellent regio- and diastereoselectivity. Density functional theory (DFT) calculations point to a crucial intermolecular hydrogen bond and π-π stacking interaction that govern selectivity in this process. PMID:27389027

  20. Diastereoselective Total Synthesis of (-)-Galiellalactone.

    PubMed

    Kim, Taewoo; Han, Young Taek; An, Hongchan; Kim, Kyeojin; Lee, Jeeyeon; Suh, Young-Ger

    2015-12-18

    An enantioselective total synthesis of (-)-galiellalactone has been accomplished. The key features of the synthesis involve the highly stereoselective construction of the cis-trisubstituted cyclopentane intermediate by a Pd(0)-catalyzed cyclization, the stereospecific introduction of an angular hydroxyl group by Riley oxidation, and the efficient construction of the tricyclic system of (-)-galiellalactone via a combination of diastereoselective Hosomi-Sakurai crotylation and ring-closing metathesis (RCM). PMID:26544529

  1. Enantioselective Total Synthesis of (-)-Pironetin

    PubMed Central

    Crimmins, Michael T.; Dechert, Anne-Marie R.

    2009-01-01

    The enantioselective total synthesis of pironetin has been achieved in 11 steps from known aldehyde 2. The synthesis relies on the formation of 5 out of 6 stereocenters through titanium mediated iterative aldol reactions. Key steps in this synthesis include an acetal aldol reaction to establish the stereochemistry at C8 and C9, an acetate aldol reaction, and “Evans” syn aldol reaction. PMID:19281219

  2. Total synthesis of (-)-uniflorine A.

    PubMed

    Parmeggiani, Camilla; Martella, Daniele; Cardona, Francesca; Goti, Andrea

    2009-11-01

    Total synthesis of (-)-uniflorine A (3) has been accomplished in nine steps and 11% overall yield from carbohydrate-based nitrone 5. The key steps of the synthetic strategy were a high regio- and complete stereoselective 1,3-dipolar cycloaddition of alkene 6 with nitrone 5, a Tamao-Fleming reaction for replacing the silicon substituent with a hydroxy group with retention of configuration, and a Mitsunobu reaction to establish the correct configuration of the target molecule at C-6. PMID:19835391

  3. Intrathoracic Hernia after Total Gastrectomy

    PubMed Central

    Tashiro, Yoshihiko; Murakami, Masahiko; Otsuka, Koji; Saito, Kazuhiko; Saito, Akira; Motegi, Kentaro; Date, Hiromi; Yamashita, Takeshi; Ariyoshi, Tomotake; Goto, Satoru; Yamazaki, Kimiyasu; Fujimori, Akira; Watanabe, Makoto; Aoki, Takeshi

    2016-01-01

    Intrathoracic hernias after total gastrectomy are rare. We report the case of a 78-year-old man who underwent total gastrectomy with antecolic Roux-Y reconstruction for residual gastric cancer. He had alcoholic liver cirrhosis and received radical laparoscopic proximal gastrectomy for gastric cancer 3 years ago. Early gastric cancer in the remnant stomach was found by routine upper gastrointestinal endoscopy. We initially performed endoscopic submucosal dissection, but the vertical margin was positive in a pathological result. We performed total gastrectomy with antecolic Roux-Y reconstruction by laparotomy. For adhesion of the esophageal hiatus, the left chest was connected with the abdominal cavity. A pleural defect was not repaired. Two days after the operation, the patient was suspected of having intrathoracic hernia by chest X-rays. Computed tomography showed that the transverse colon and Roux limb were incarcerated in the left thoracic cavity. He was diagnosed with intrathoracic hernia, and emergency reduction and repair were performed. Operative findings showed that the Roux limb and transverse colon were incarcerated in the thoracic cavity. After reduction, the orifice of the hernia was closed by suturing the crus of the diaphragm with the ligament of the jejunum and omentum. After the second operation, he experienced anastomotic leakage and left pyothorax. Anastomotic leakage was improved with conservative therapy and he was discharged 76 days after the second operation.

  4. Total Pancreatectomy With Islet Autotransplantation

    PubMed Central

    Bellin, Melena D.; Gelrud, Andres; Arreaza-Rubin, Guillermo; Dunn, Ty B.; Humar, Abhinav; Morgan, Katherine A.; Naziruddin, Bashoo; Rastellini, Cristiana; Rickels, Michael R.; Schwarzenberg, Sarah J.; Andersen, Dana K.

    2015-01-01

    A workshop sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases focused on research gaps and opportunities in total pancreatectomy with islet autotransplantation (TPIAT) for the management of chronic pancreatitis. The session was held on July 23, 2014 and structured into 5 sessions: (1) patient selection, indications, and timing; (2) technical aspects of TPIAT; (3) improving success of islet autotransplantation; (4) improving outcomes after total pancreatectomy; and (5) registry considerations for TPIAT. The current state of knowledge was reviewed; knowledge gaps and research needs were specifically highlighted. Common themes included the need to identify which patients best benefit from and when to intervene with TPIAT, current limitations of the surgical procedure, diabetes remission and the potential for improvement, opportunities to better address pain remission, GI complications in this population, and unique features of children with chronic pancreatitis considered for TPIAT. The need for a multicenter patient registry that specifically addresses the complexities of chronic pancreatitis and total pancreatectomy outcomes and postsurgical diabetes outcomes was repeatedly emphasized. PMID:25599324

  5. Fatigue evaluation of composite-reinforced, integrally stiffened metal panels

    NASA Technical Reports Server (NTRS)

    Dumesnil, C. E.

    1973-01-01

    The fatigue behavior of composite-reinforced, integrally stiffened metal panels was investigated in combined metal and composite materials subjected to fatigue loading. The systems investigated were aluminum-graphite/epoxy, and aluminum-S glass/epoxy. It was found that the composite material would support the total load at limit stress after the metal had completely failed, and the weight of the composite-metal system would be equal to that of an all metal system which would carry the same total load at limit stress.

  6. Chiral anomaly and transport in Weyl metals

    NASA Astrophysics Data System (ADS)

    Burkov, A. A.

    2015-03-01

    We present an overview of our recent work on transport phenomena in Weyl metals, which may be connected to their nontrivial topological properties, particularly to chiral anomaly. We argue that there are two basic phenomena, which are related to chiral anomaly in Weyl metals: anomalous Hall effect (AHE) and chiral magnetic effect (CME). While AHE is in principle present in any ferromagnetic metal, we demonstrate that a magnetic Weyl metal is distinguished from an ordinary ferromagnetic metal by the absence of the extrinsic and the Fermi surface part of the intrinsic contributions to the AHE, as long as the Fermi energy is sufficiently close to the Weyl nodes. The AHE in a Weyl metal is thus shown to be a purely intrinsic, universal property, fully determined by the location of the Weyl nodes in the first Brillouin zone. In other words, a ferromagnetic Weyl metal may be thought of as the only example of a ferromagnetic metal with a purely intrinsic AHE. We further develop a fully microscopic theory of diffusive magnetotransport in Weyl metals. We derive coupled diffusion equations for the total and axial (i.e. node-antisymmetric) charge densities and show that chiral anomaly manifests as a magnetic-field-induced coupling between them. We demonstrate that an experimentally-observable consequence of CME in magnetotransport in Weyl metals is a quadratic negative magnetoresistance, which will dominate all other contributions to magnetoresistance under certain conditions and may be regarded as a smoking-gun transport characteristic, unique to Weyl metals.

  7. Chiral anomaly and transport in Weyl metals.

    PubMed

    Burkov, A A

    2015-03-25

    We present an overview of our recent work on transport phenomena in Weyl metals, which may be connected to their nontrivial topological properties, particularly to chiral anomaly. We argue that there are two basic phenomena, which are related to chiral anomaly in Weyl metals: anomalous Hall effect (AHE) and chiral magnetic effect (CME). While AHE is in principle present in any ferromagnetic metal, we demonstrate that a magnetic Weyl metal is distinguished from an ordinary ferromagnetic metal by the absence of the extrinsic and the Fermi surface part of the intrinsic contributions to the AHE, as long as the Fermi energy is sufficiently close to the Weyl nodes. The AHE in a Weyl metal is thus shown to be a purely intrinsic, universal property, fully determined by the location of the Weyl nodes in the first Brillouin zone. In other words, a ferromagnetic Weyl metal may be thought of as the only example of a ferromagnetic metal with a purely intrinsic AHE. We further develop a fully microscopic theory of diffusive magnetotransport in Weyl metals. We derive coupled diffusion equations for the total and axial (i.e. node-antisymmetric) charge densities and show that chiral anomaly manifests as a magnetic-field-induced coupling between them. We demonstrate that an experimentally-observable consequence of CME in magnetotransport in Weyl metals is a quadratic negative magnetoresistance, which will dominate all other contributions to magnetoresistance under certain conditions and may be regarded as a smoking-gun transport characteristic, unique to Weyl metals. PMID:25712419

  8. Alkali metal sources for OLED devices

    NASA Astrophysics Data System (ADS)

    Cattaneo, Lorena; Longoni, Giorgio; Bonucci, Antonio; Tominetti, Stefano

    2005-07-01

    In OLED organic layers electron injection is improved by using alkali metals as cathodes, to lower work function or, as dopants of organic layer at cathode interface. The creation of an alkali metal layer can be accomplished through conventional physical vapor deposition from a heated dispenser. However alkali metals are very reactive and must be handled in inert atmosphere all through the entire process. If a contamination takes place, it reduces the lithium deposition rate and also the lithium total yield in a not controlled way. An innovative alkali metal dispensing technology has been developed to overcome these problems and ensure OLED alkali metal cathode reliability. The alkali Metal dispenser, called Alkamax, will be able to release up to a few grams of alkali metals (in particular Li and Cs) throughout the adoption of a very stable form of the alkali metal. Lithium, for example, can be evaporated "on demand": the evaporation could be stopped and re-activated without losing alkali metal yield because the metal not yet consumed remains in its stable form. A full characterization of dispensing material, dispenser configuration and dispensing process has been carried out in order to optimize the evaporation and deposition dynamics of alkali metals layers. The study has been performed applying also inside developed simulations tools.

  9. Impact of metals on the biodegradation of organic pollutants.

    PubMed Central

    Sandrin, Todd R; Maier, Raina M

    2003-01-01

    Forty percent of hazardous waste sites in the United States are co-contaminated with organic and metal pollutants. Data from both aerobic and anaerobic systems demonstrate that biodegradation of the organic component can be reduced by metal toxicity. Metal bioavailability, determined primarily by medium composition/soil type and pH, governs the extent to which metals affect biodegradation. Failure to consider bioavailability rather than total metal likely accounts for much of the enormous variability among reports of inhibitory concentrations of metals. Metals appear to affect organic biodegradation through impacting both the physiology and ecology of organic degrading microorganisms. Recent approaches to increasing organic biodegradation in the presence of metals involve reduction of metal bioavailability and include the use of metal-resistant bacteria, treatment additives, and clay minerals. The addition of divalent cations and adjustment of pH are additional strategies currently under investigation. PMID:12826480

  10. "Soft" metallic contact to isolated C60 molecules.

    PubMed

    Glowatzki, Hendrik; Bröker, Benjamin; Blum, Ralf-Peter; Hofmann, Oliver T; Vollmer, Antje; Rieger, Ralph; Müllen, Klaus; Zojer, Egbert; Rabe, Jürgen P; Koch, Norbert

    2008-11-01

    C60 adsorbed on a monolayer of hexaazatriphenylene-hexanitrile (HATCN) on Ag(111) is investigated by ultraviolet photoelectron spectroscopy (UPS) and scanning tunneling microscopy. UPS and quantum-mechanical modeling show that HATCN chemisorbed on Ag(111) displays metallic character. This metallic molecular layer decouples C60 electronically from the Ag substrate and simultaneously acts both as template for the stable adsorption of isolated C60 molecules at room temperature and as "soft" metallic contact for subsequently deposited molecules. PMID:18954123

  11. Mechanochemical processing for metals and metal alloys

    DOEpatents

    Froes, Francis H.; Eranezhuth, Baburaj G.; Prisbrey, Keith

    2001-01-01

    A set of processes for preparing metal powders, including metal alloy powders, by ambient temperature reduction of a reducible metal compound by a reactive metal or metal hydride through mechanochemical processing. The reduction process includes milling reactants to induce and complete the reduction reaction. The preferred reducing agents include magnesium and calcium hydride powders. A process of pre-milling magnesium as a reducing agent to increase the activity of the magnesium has been established as one part of the invention.

  12. Long-acting muscarinic antagonists.

    PubMed

    Melani, Andrea S

    2015-01-01

    Chronic obstructive pulmonary disease (COPD) is a major cause of death and disability worldwide. Inhaled bronchodilators are the mainstay of COPD pharmacological treatment. Long-acting muscarinic antagonists (LAMAs) are a major class of inhaled bronchodilators. Some LAMA/device systems with different characteristics and dosing schedules are currently approved for maintenance therapy of COPD and a range of other products are being developed. They improve lung function and patient-reported outcomes and reduce acute bronchial exacerbations with good safety. LAMAs are used either alone or associated with long-acting β₂-agonists, eventually in fixed dose combinations. Long-acting β₂-agonist/LAMA combinations assure additional benefits over the individual components alone. The reader will obtain a view of the safety and efficacy of the different LAMA/device systems in COPD patients. PMID:26109098

  13. 7 CFR 1150.101 - Act.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Orders; Milk), DEPARTMENT OF AGRICULTURE DAIRY PROMOTION PROGRAM Dairy Promotion and Research Order Definitions § 1150.101 Act. Act means Title I, Subtitle B, of the Dairy and Tobacco Adjustment Act of...

  14. 7 CFR 1150.101 - Act.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ORDERS; MILK), DEPARTMENT OF AGRICULTURE DAIRY PROMOTION PROGRAM Dairy Promotion and Research Order Definitions § 1150.101 Act. Act means Title I, Subtitle B, of the Dairy and Tobacco Adjustment Act of...

  15. 7 CFR 1150.101 - Act.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Orders; Milk), DEPARTMENT OF AGRICULTURE DAIRY PROMOTION PROGRAM Dairy Promotion and Research Order Definitions § 1150.101 Act. Act means Title I, Subtitle B, of the Dairy and Tobacco Adjustment Act of...

  16. 7 CFR 1150.101 - Act.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ORDERS; MILK), DEPARTMENT OF AGRICULTURE DAIRY PROMOTION PROGRAM Dairy Promotion and Research Order Definitions § 1150.101 Act. Act means Title I, Subtitle B, of the Dairy and Tobacco Adjustment Act of...

  17. [Suicide, a philosophical act or an act of depression?].

    PubMed

    Heslon, Christian

    2016-01-01

    Suicide is more frequent in people aged over 75 than in the rest of the population. Is it the fact of feeling too old or of being alone? Is the person fully lucid? The question of responsibility is raised, as is the meaning of the act: the ultimate living gesture or capitulation in the face of death? PMID:27173624

  18. Get Your ACT Together: A Resource Guide for ACT Preparation.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Education, Oklahoma City.

    This guide is designed as a resource for (1) Oklahoma teachers, counselors, and parents, to help them help their students prepare for the ACT assessment; and (2) students, to help dispel some common myths and misunderstandings as they prepare for the test. Section A, for administrators, teachers, counselors, Indian program staffs, and…

  19. Assessing metal bioavailability from cytosolic metal concentrations in natural populations of aquatic insects

    SciTech Connect

    Cain, D.J.; Luoma, S.N.; Hornberger, M.I.

    1995-12-31

    Metals occur in a variety of forms in aquatic insects. Some of these forms may be irrelevant to effects of metals on the animal, and might actually obscure links between tissue residues, metal bioavailability and toxicity (e.g. metals sorbed to external body parts, or associated with unpurged gut contents). Cytosolic metal may be a sensitive indicator of metal bioavailability and toxicity. The authors determined cytosolic metal concentrations in natural populations of the caddisfly (Trichoptera) Hydropsyche occidentalis. Cytosolic metal concentrations were compared to whole-body and sediment metal concentrations. Samples were collected along a contamination gradient over a 380 km reach of the Clark Fork River, Montana, in August of 1992 and 1993. Concentrations of cytosolic Cd, Cu, and Pb correlated with concentrations of these metals in the whole body within years. Cytosolic metals also correlated with levels of sediment contamination except at the most contaminated sites where metal concentrations in the cytosol were lower relative to sediments. The availability of Pb appeared to be low since the cytosolic Pb fraction represented less than 6% of the total Pb body burden. The cytosol contained appreciably higher proportions of the total Cd and Cu body burden than Pb. The cytosolic fraction of Cd and Cu also increased significantly between 1992 and 1993. This change reflected an increase in Cd and Cu exposure in 1993, apparently due to the mobilization of metals during higher river flows that year. The shift in cytosolic metal fractions demonstrates the dynamic nature of metal partitioning in animals in nature. These shifts can be influenced by hydrologic and geochemical conditions, as well as biological processes.

  20. Advanced Communications Technology Satellite (ACTS)

    NASA Astrophysics Data System (ADS)

    Gedney, Richard T.; Schertler, Ronald J.

    1989-06-01

    The NASA Advanced Communications Technology Satellite (ACTS) was conceived to help maintain U.S. leadership in the world's communications-satellite market. This experimental satellite is expected to be launched by NASA in 1992 and to furnish the technology necessary for establishing very small aperture terminal digital networks which provide on-demand full-mesh connectivity, and 1.544-MBPS services with only a single hop. Utilizing on-board switching and processing, each individual voice or data circuit can be separately routed to any location in the network. This paper provides an overview of the ACTS and discusses the value of the technology for future communications systems.