WorldWideScience

Sample records for highly contaminated preparations

  1. Initial characterization of a highly contaminated high explosives outfall in preparation for in situ bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Betty A. Strietelmeier; Patrick J. Coyne; Patricia A. Leonard; W. Lamar Miller; Jerry R. Brian

    1999-12-01

    In situ bioremediation is a viable, cost-effective treatment for environmental contamination of many kinds. The feasibility of using biological techniques to remediate soils contaminated with high explosives (HE) requires laboratory evaluation before proceeding to a larger scale field operation. Laboratory investigations have been conducted at pilot scale which indicate that an anaerobic process could be successful at reducing levels of HE, primarily HMX, RDX and TNT, in contaminated soils. A field demonstration project has been designed to create an anaerobic environment for the degradation of HE materials. The first step in this project, initial characterization of the test area, was conducted and is the subject of this report. The levels of HE compounds found in the samples from the test area were higher than the EPA Method 8330 was able to extract without subsequent re-precipitation; therefore, a new method was developed using a superior extractant system. The test area sampling design was relatively simple as one might expect in an initial characterization. A total of 60 samples were each removed to a depth of 4 inches using a 1 inch diameter corer. The samples were spaced at relatively even intervals across a 20 foot cross-section through the middle of four 7-foot-long adjacent plots which are designed to be a part of an in situ bioremediation experiment. Duplicate cores were taken from each location for HE extraction and analysis in order to demonstrate and measure the heterogeneity of the contamination. Each soil sample was air dried and ball-milled to provide a homogeneous solid for extraction and analysis. Several samples had large consolidated pieces of what appeared to be solid HE. These were not ball-milled due to safety concerns, but were dissolved and the solutions were analyzed. The new extraction method was superior in that results obtained for several of the contaminants were up to 20 times those obtained with the EPA extraction method. The

  2. Environmental contamination, product contamination and workers exposure using a robotic system for antineoplastic drug preparation.

    Science.gov (United States)

    Sessink, Paul J M; Leclercq, Gisèle M; Wouters, Dominique-Marie; Halbardier, Loïc; Hammad, Chaïma; Kassoul, Nassima

    2015-04-01

    Environmental contamination, product contamination and technicians exposure were measured following preparation of iv bags with cyclophosphamide using the robotic system CytoCare. Wipe samples were taken inside CytoCare, in the clean room environment, from vials, and prepared iv bags including ports and analysed for contamination with cyclophosphamide. Contamination with cyclophosphamide was also measured in environmental air and on the technicians hands and gloves used for handling the drugs. Exposure of the technicians to cyclophosphamide was measured by analysis of cyclophosphamide in urine. Contamination with cyclophosphamide was mainly observed inside CytoCare, before preparation, after preparation and after daily routine cleaning. Contamination outside CytoCare was incidentally found. All vials with reconstituted cyclophosphamide entering CytoCare were contaminated on the outside but vials with powdered cyclophosphamide were not contaminated on the outside. Contaminated bags entering CytoCare were also contaminated after preparation but non-contaminated bags were not contaminated after preparation. Cyclophosphamide was detected on the ports of all prepared bags. Almost all outer pairs of gloves used for preparation and daily routine cleaning were contaminated with cyclophosphamide. Cyclophosphamide was not found on the inner pairs of gloves and on the hands of the technicians. Cyclophosphamide was not detected in the stationary and personal air samples and in the urine samples of the technicians. CytoCare enables the preparation of cyclophosphamide with low levels of environmental contamination and product contamination and no measurable exposure of the technicians.

  3. Simultaneous extraction and cleanup of high-lipid organs from white sturgeon (Acipenser transmontanus) for multiple legacy and emerging organic contaminants using QuEChERS sample preparation.

    Science.gov (United States)

    Morrison, Shane A; Sieve, Kristal K; Ratajczak, Robert E; Bringolf, Robert B; Belden, Jason B

    2016-01-01

    The objective of this research was to utilize the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method to extract a broad range of persistent organic pollutants from sturgeon organs (liver and gonad) as indicators of exposure. The analyte list was prioritized to include carcinogenic polyaromatic hydrocarbons (PAHs), the most commonly occurring polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs), persistent bioaccumulative and toxic chemicals (PBTs), and emergent contaminants of concern (ECCs) as indicators of human sewage exposure. White sturgeon (Acipenser transmontanus) were selected for this study to support a larger ecotoxicological study to monitor contaminants as an assessment of fish health. Organ tissues contained high lipid content with percentages of 15% and 34% for liver and gonad, respectively. Overall recoveries from fortified sturgeon tissues were high, 71-98% for PAHs, 60-107% for PBDEs and PCBs, 86-107% for PBT chemicals, and 88-107% for ECCs with the exception of octinoxate (28%) from liver tissues. Analyte recovery trends decreased as analyte lipophilicity and molecular weight increased. These recoveries demonstrate that extraction using QuEChERS can be used for screening of the most common bioaccumulating organic compounds in high lipid fish tissue using a single extraction and analysis.

  4. Standard Practice for Preparation of Aerospace Contamination Control Plans

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This practice is intended to assist in the preparation of formal plans for contamination control, especially of aerospace critical surfaces. Requirements may be established at the systems level, either by the customer or the systems integrator, or at the subsystem level. Subsystem requirements may be imposed by the responsible subsystem supplier or they may be flowed down from the systems organization (4.7). The extent of detail and level of cleanliness required can vary with the particular application and type of hardware being built, but all aspects of contamination control must be included in a final plan. Therefore, each of the following elements must be considered for inclusion in a contamination control plan (CCP): 1.1.1 Cleanliness requirements for deliverable hardware addressing particulate, molecular, or biological contaminants or combination thereof. Specify contamination limits and any budget allocations. 1.1.2 Implementation plans to achieve, verify, and maintain the specified cleanliness re...

  5. Bacterial contamination of hospital-prepared enteral tube feeding formulas in Isfahan, Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Jalali

    2009-05-01

    Full Text Available

    • BACKGROUND: Hospital-prepared tube feedings from three intensive care units of two hospitals in Isfahan, Iran were analyzed for microbial contamination.
    • METHODS: A total number of 152 samples (76 samples each at the time of preparation and 18 hours following preparation were collected. Standard plate count, coliform count and Staphylococcus aureus count for all samples were conducted. Samples were analyzed also for the presence of Salmonella spp. and Listeria spp.
    • RESULTS: At the time of food preparation, out of 76 samples, 53 samples (70% had coliform contamination and 87% of these contaminated samples had counts greater than 101 cfu/g. Also, 68  amples (90% had S. aureus contamination greater than 101 cfu/g. In standard plate count, 74 samples (97% had counts greater than 103 cfu/g, while 54 samples (71% had counts greater than 104 cfu/g. In second sampling occasion, out of 76 samples, 68 samples (90% had coliform contamination and 84% of these contaminated samples had counts greater than 101 cfu/g. Also, 72 samples (95% had S. aureus contamination, 98.6% of these contaminated samples had counts greater than 102 cfu/g. In standard plate count, 74 samples (97% had counts greater than 104 cfu/g. No Salmonella or Listeria was detected from samples.
    • CONCLUSION: The results indicated that a majority of the blenderized enteral tube feedings in those hospitals are not safe. In comparison to the standard limits, these enteral tube feedings are highly  ontaminated and posed substantial risk for developing a foodborne disease or nosocomial infection.
    • KEYWORDS: Enteral Feeding, Microbial Contamination, Nosocomial Infection, Standard Plate Count, Coliform.

  6. Microfluidic Sample Preparation Methods for the Analysis of Milk Contaminants

    Directory of Open Access Journals (Sweden)

    Andrea Adami

    2016-01-01

    Full Text Available In systems for food analysis, one of the major challenges is related to the quantification of specific species into the complex chemical and physical composition of foods, that is, the effect of “matrix”; the sample preparation is often the key to a successful application of biosensors to real measurements but little attention is traditionally paid to such aspects in sensor research. In this critical review, we discuss several microfluidic concepts that can play a significant role in sample preparation, highlighting the importance of sample preparation for efficient detection of food contamination. As a case study, we focus on the challenges related to the detection of aflatoxin M1 in milk and we evaluate possible approaches based on inertial microfluidics, electrophoresis, and acoustic separation, compared with traditional laboratory and industrial methods for phase separation as a baseline of thrust and well-established techniques.

  7. Toxic element contamination of natural health products and pharmaceutical preparations.

    Directory of Open Access Journals (Sweden)

    Stephen J Genuis

    Full Text Available BACKGROUND: Concern has recently emerged regarding the safety of natural health products (NHPs-therapies that are increasingly recommended by various health providers, including conventional physicians. Recognizing that most individuals in the Western world now consume vitamins and many take herbal agents, this study endeavored to determine levels of toxic element contamination within a range of NHPs. METHODS: Toxic element testing was performed on 121 NHPs (including Ayurvedic, traditional Chinese, and various marine-source products as well as 49 routinely prescribed pharmaceutical preparations. Testing was also performed on several batches of one prenatal supplement, with multiple samples tested within each batch. Results were compared to existing toxicant regulatory limits. RESULTS: Toxic element contamination was found in many supplements and pharmaceuticals; levels exceeding established limits were only found in a small percentage of the NHPs tested and none of the drugs tested. Some NHPs demonstrated contamination levels above preferred daily endpoints for mercury, cadmium, lead, arsenic or aluminum. NHPs manufactured in China generally had higher levels of mercury and aluminum. CONCLUSIONS: Exposure to toxic elements is occurring regularly as a result of some contaminated NHPs. Best practices for quality control-developed and implemented by the NHP industry with government oversight-is recommended to guard the safety of unsuspecting consumers.

  8. Preparation of High Shrinkage Polypropylene

    Institute of Scientific and Technical Information of China (English)

    吕文军; 王华平; 李建梅; 张玉梅

    2001-01-01

    The common PP chips have been used to prepare high shrinkage PP fibers with shrinkage in boiling water higher than 50%. Meanwhile, the process conditions on fiber structure and properties have been discussed in detail. With the increase of drawing temperature, the shrinkage in boiling water of the fiber increases at first,and then decreases in the temperature range from 70℃ to 100℃. The better drawing temperature is from 75℃ to 85℃ according to the melt index of the PP material. The shrinkage in boiling water of PP fiber increases with the increase of pump delivery. The orientation factor and crystallinity increase with the increase of drawing temperature. With an increase in drawing temperature,unit-cell numbers and monomer unit numbers in every crystal nucleus tend to increase, but unit volume crystal nucleus tend to reduce.

  9. Contamination and Surface Preparation Effects on Composite Bonding

    Science.gov (United States)

    Kutscha, Eileen O.; Vahey, Paul G.; Belcher, Marcus A.; VanVoast, Peter J.; Grace, William B.; Blohowiak, Kay Y.; Palmieri, Frank L.; Connell, John W.

    2017-01-01

    Results presented here demonstrate the effect of several prebond surface contaminants (hydrocarbon, machining fluid, latex, silicone, peel ply residue, release film) on bond quality, as measured by fracture toughness and failure modes of carbon fiber reinforced epoxy substrates bonded in secondary and co-bond configurations with paste and film adhesives. Additionally, the capability of various prebond surface property measurement tools to detect contaminants and potentially predict subsequent bond performance of three different adhesives is also shown. Surface measurement methods included water contact angle, Dyne solution wettability, optically stimulated electron emission spectroscopy, surface free energy, inverse gas chromatography, and Fourier transform infrared spectroscopy with chemometrics analysis. Information will also be provided on the effectiveness of mechanical and energetic surface treatments to recover a bondable surface after contamination. The benefits and drawbacks of the various surface analysis tools to detect contaminants and evaluate prebond surfaces after surface treatment were assessed as well as their ability to correlate to bond performance. Surface analysis tools were also evaluated for their potential use as in-line quality control of adhesive bonding parameters in the manufacturing environment.

  10. Removal of tetracycline from contaminated water by Moringa oleifera seed preparations.

    Science.gov (United States)

    Santos, Andréa F S; Matos, Maria; Sousa, Ângela; Costa, Cátia; Nogueira, Regina; Teixeira, José A; Paiva, Patrícia M G; Parpot, Pier; Coelho, Luana C B B; Brito, António G

    2016-01-01

    The aim of this study was to evaluate tetracycline antibiotic (TA) removal from contaminated water by Moringa oleifera seed preparations. The composition of synthetic water approximate river natural contaminated water and TA simulated its presence as an emerging pollutant. Interactions between TA and protein preparations (extract; fraction and lectin) were also evaluated. TA was determined by solid-phase extraction followed by high-performance liquid chromatography-mass spectrometry. Moringa extract and flour removed TA from water. The extract removed TA in all concentrations, and better removal (40%) was obtained with 40 mg L(-1); seed flour (particles  5 mm (0.50 g L(-1)) removed 55% of antibiotic. Interactions between TA and seed preparations were assayed by haemagglutinating activity (HA). Specific HA (SHA) of extract (pH 7) was abolished with tetracycline (5 mg L(-1)); fraction (75%) and lectin HA (97%) were inhibited with TA. Extract SHA decreased by 75% at pH 8. Zeta potential (ZP) of extract 700 mg L(-1) and tetracycline 50 mg L(-1) , pH range 5-8, showed different results. Extract ZP was more negative (-10.73 to -16.00 mV) than tetracycline ZP (-0.27 to -20.15 mV); ZP difference was greater in pH 8. The focus of this study was achieved since Moringa preparations removed TA from water and compounds interacting with tetracycline involved at least lectin-binding sites. This is a natural process, which do not promote environmental damage.

  11. Performance of food safety management systems in poultry meat preparation processing plants in relation to Campylobacter spp. contamination.

    Science.gov (United States)

    Sampers, Imca; Jacxsens, Liesbeth; Luning, Pieternel A; Marcelis, Willem J; Dumoulin, Ann; Uyttendaele, Mieke

    2010-08-01

    A diagnostic instrument comprising a combined assessment of core control and assurance activities and a microbial assessment instrument were used to measure the performance of current food safety management systems (FSMSs) of two poultry meat preparation companies. The high risk status of the company's contextual factors, i.e., starting from raw materials (poultry carcasses) with possible high numbers and prevalence of pathogens such as Campylobacter spp., requires advanced core control and assurance activities in the FSMS to guarantee food safety. The level of the core FSMS activities differed between the companies, and this difference was reflected in overall microbial quality (mesophilic aerobic count), presence of hygiene indicators (Enterobacteriaceae, Staphylococcus aureus, and Escherichia coli), and contamination with pathogens such as Salmonella, Listeria monocytogenes, and Campylobacter spp. The food safety output expressed as a microbial safety profile was related to the variability in the prevalence and contamination levels of Campylobacter spp. in poultry meat preparations found in a Belgian nationwide study. Although a poultry meat processing company could have an advanced FSMS in place and a good microbial profile (i.e., lower prevalence of pathogens, lower microbial numbers, and less variability in microbial contamination), these positive factors might not guarantee pathogen-free products. Contamination could be attributed to the inability to apply effective interventions to reduce or eliminate pathogens in the production chain of (raw) poultry meat preparations.

  12. Quantification of Campylobacter jejuni Cross-Contamination via Hands, Cutlery, and Cutting Board during Preparation of a Chicken Fruit Salad

    National Research Council Canada - National Science Library

    Verhoeff-Bakkenes, L; Beumer, R.R; de Jonge, R; van Leusden, F.M; de Jong, A.E.I

    2008-01-01

    ... of a chicken salad was tested to identify the most critical transfer route. The end contamination level of salads prepared according to different scenarios, with or without cross-contamination, was compared...

  13. Examination of background contamination levels for gas counting and AMS target preparation in Trondheim

    DEFF Research Database (Denmark)

    Gulliksen, S.; Thomsen, M.S.

    1992-01-01

    conventional gas proportional counting (GPC) system. We have also studied contamination levels of our target preparation for C-14 accelerator mass spectrometry (AMS) dating in Uppsala. A significant lower background is obtained for Icelandic double spar than for marbles, probably due to a crystal structure...... of the double spar that is more insensitive to contaminating processes. The background for combusted samples is at the same level as for samples of double spar, indicating that additional C-14 contamination due to combustion is negligible. Dates obtained on interstadial samples (T >30 ka BP) by both GPC and AMS...

  14. Immunostimulatory Potential of β-Lactoglobulin Preparations: Effects Caused by Endotoxin Contamination

    DEFF Research Database (Denmark)

    Pedersen, Susanne Brix; Bovetto, L.; Fritsche, R.

    2003-01-01

    the immunomodulatory activity. Eventually, the immunostimulatory effect was found to be caused by endotoxin contamination.Conclusion: These results identify endotoxin as the main immunostimulatory component present in some commercial beta-lactoglobulin preparations. Moreover, the present study makes it evident...

  15. Activated carbon prepared from coffee pulp: potential adsorbent of organic contaminants in aqueous solution.

    Science.gov (United States)

    Gonçalves, Maraisa; Guerreiro, Mário César; Ramos, Paulize Honorato; de Oliveira, Luiz Carlos Alves; Sapag, Karim

    2013-01-01

    The processing of coffee beans generates large amounts of solid and liquid residues. The solid residues (pulp, husk and parchment) represent a serious environmental problem and do not have an adequate disposal mechanism. In this work, activated carbons (ACs) for adsorption of organic compounds were prepared from coffee pulp by controlled temperature at different pulp/Na2HPO4 ratios (4:1, 2:1, 5:4 and 1:1). The N2 adsorption/desorption isotherms showed ACs with high quantities of mesopores and micropores and specific surface areas of 140, 150, 450 and 440 m(2)g(-1) for AC 4:1, AC 2:1, AC 5:4 and AC 1:1, respectively. The prepared material AC 5:4 showed a higher removal capacity of the organic contaminants methylene blue (MB), direct red (DR) and phenol than did a Merck AC. The maximum capacities for this AC are approximately 150, 120 and 120 mg g(-1) for MB, DR and phenol, respectively. Thus, a good adsorbent was obtained from coffee pulp, an abundant Brazilian residue.

  16. HIGH VELOCITY THERMAL GUN FOR SURFACE PREPARATION AND TREATMENT

    Directory of Open Access Journals (Sweden)

    I.A. Gorlach

    2012-01-01

    Full Text Available Many surface preparation and treatment processes utilise compressed air to propel particles against surfaces in order to clean and treat them. The effectiveness of the processes depends on the velocity of the particles, which in turn depends on the pressure of the compressed air. This paper describes a thermal gun built on the principles of High Velocity Air Fuel (HVAF and High Velocity Oxy Fuel (HVOF processes. The designed apparatus can be used for abrasive blasting, coating of surfaces, cutting of rocks, removing rubber from mining equipment, cleaning of contaminations etc.

  17. High-pressure saline washing of allografts reduces bacterial contamination.

    Science.gov (United States)

    Hirn, M Y; Salmela, P M; Vuento, R E

    2001-02-01

    60 fresh-frozen bone allografts were contaminated on the operating room floor. No bacterial growth was detected in 5 of them after contamination. The remaining 55 grafts had positive bacterial cultures and were processed with three methods: soaking in saline, soaking in antibiotic solution or washing by high-pressure saline. After high-pressure lavage, the cultures were negative in three fourths of the contaminated allografts. The corresponding figures after soaking grafts in saline and antibiotic solution were one tenth and two tenths, respectively. High-pressure saline cleansing of allografts can be recommended because it improves safety by reducing the superficial bacterial bioburden.

  18. Pleasure Boatyard Soils are Often Highly Contaminated

    OpenAIRE

    Eklund, Britta; Eklund, David

    2014-01-01

    The contamination in pleasure boatyards has been investigated. Measured concentrations of copper, zinc, lead, mercury, cadmium, tributyltin (TBT), the 16 most common polycyclic aromatic hydrocarbons (∑16 PAHs), and the seven most common polychlorinated biphenyls (∑7 PCBs) from investigations at 34 boatyards along the Swedish coast have been compiled. The maximum concentrations were 7,700 for Cu, 10,200, for Zn, 40,100 for Pb, 188 for Hg, 18 for Cd, 107 for TBT, 630 for carcinogenic PAHs, 1,48...

  19. Processing practices contributing to Campylobacter contamination in Belgian chicken meat preparations.

    Science.gov (United States)

    Sampers, Imca; Habib, Ihab; Berkvens, Dirk; Dumoulin, Ann; Zutter, Lieven De; Uyttendaele, Mieke

    2008-12-10

    The aim of this study was to obtain insight into processing practices in the poultry sector contributing to the variability in Campylobacter contamination in Belgian chicken meat preparations. This was achieved by company profiling of eleven food business operators, in order to evaluate variation of processing management, in addition to statistical modelling of microbiological testing results for Campylobacter spp. contamination in 656 end product samples. Almost half (48%) of chicken meat preparation samples were positive for Campylobacter spp. Results revealed a statistically significant variation in Campylobacter contamination between 11 chicken meat producers across Belgium at both quantitative and qualitative detection levels. All producers provided Campylobacter-positive samples, but prevalence ranged from 9% up to 85% at single producer level. The presence or addition of skin during production of chicken meat preparations resulted in almost 2.2-fold increase in the probability of a sample being positive for Campylobacter, while chicken meat preparations made from frozen meat, or partly containing pre-frozen meat, had a significant (Odds Ratio=0.41; CI 95% 0.18:0.98) lower probability of being positive for Campylobacter. However, the quantitative results indicated that the positive freezing effect on Campylobacter count was compromised by the presence and/or adding of skin.

  20. Preparation of Silica/Reduced Graphene Oxide Nanosheet Composites for Removal of Organic Contaminants from Water.

    Science.gov (United States)

    Li, Wen; Liu, Wei; Wang, Haifei; Lu, Wensheng

    2016-06-01

    Graphene-based composites open up new opportunities as effective adsorbents for the removal of organic contaminants from water. In this article, we report a novel and facile process to synthesize well-dispersed silica/reduced graphene oxide (SiO2/RGO) nanosheet composites. The SiO2/RGO nanosheet composites are prepared through a modified sol-gel process with in situ hydrolysis of tetraethoxysilane (TEOS) on graphene oxide (GO) nanosheet, followed by reduction of GO to graphene. In comparison with the RGO nanosheets, the as-prepared SiO2/RGO nanosheet composites have a larger surface area and good aqueous disperse ability. In addition, the application of SiO2/RGO nanosheet composites was demonstrated on removing organic dyes from water. The SiO2/RGO nanosheet composites show rapid and stable adsorption performance on removal of Methylene Blue (MB) and thionine (TH) from water. It is indicated that the resulting SiO2/RGO composites can be utilized as efficient adsorbents for the removal of organic contaminants from water.

  1. Alternative preparation of inclusion bodies excludes interfering non-protein contaminants and improves the yield of recombinant proinsulin.

    Science.gov (United States)

    Mackin, Robert B

    2014-01-01

    The goal of simple, high-yield expression and purification of recombinant human proinsulin has proven to be a considerable challenge. First, proinsulin forms inclusion bodies during bacterial expression. While this phenomenon can be exploited as a capture step, conventionally prepared inclusion bodies contain significant amounts of non-protein contaminants that interfere with subsequent chromatographic purification. Second, the proinsulin molecules within the inclusion bodies are incorrectly folded, and likely cross-linked to one another, making it difficult to quantify the amount of expressed proinsulin. Third, proinsulin is an intermediate between the initial product of ribosomal translation (preproinsulin) and the final product secreted by pancreatic beta cells (insulin). Therefore, to be efficiently produced in bacteria, it must be produced as an N-terminally extended fusion protein, which has to be converted to authentic proinsulin during the purification scheme. To address all three of these problems, while simultaneously streamlining the procedure and increasing the yield of recombinant proinsulin, we have made three substantive modifications to our previous method for producing proinsulin:.•Conditions for the preparation of inclusion bodies have been altered so contaminants that interfere with semi-preparative reversed-phase chromatography are excluded while the proinsulin fusion protein is retained at high yield.•Aliquots are taken following important steps in the procedure and the quantity of proinsulin-related polypeptide in the sample is compared to the amount present prior to that step.•Final purification is performed using a silica-based reversed-phase matrix in place of a polystyrene-divinylbenzene-based matrix.

  2. Injections through skin colonized with Staphylococcus aureus biofilm introduce contamination despite standard antimicrobial preparation procedures

    Science.gov (United States)

    Wang, Yi; Leng, Valery; Patel, Viraj; Phillips, K. Scott

    2017-01-01

    While surgical site preparation has been extensively studied, there is little information about resistance of skin microbiota in the biofilm form to antimicrobial decontamination, and there are no quantitative models to study how biofilm might be transferred into sterile tissue/implant materials during injections for joint spine and tendon, aspiration biopsies and dermal fillers (DF). In this work, we develop two in vitro models to simulate the process of skin preparation and DF injection using pig skin and SimSkin (silicone) materials, respectively. Using the pig skin model, we tested three of the most common skin preparation wipes (alcohol, chlorhexidine and povidone iodine) and found that during wiping they reduced the biofilm bacterial burden of S. aureus (CFU cm−2) by three logs with no statistically significant differences between wipes. Using the SimSkin model, we found that transfer of viable bacteria increased with needle diameter for 30G, 25G and 18G needles. Transfer incidence decreased as injection depth was increased from 1 mm to 3 mm. Serial puncture and linear threading injection styles had similar transfer incidence, whereas fanning significantly increased transfer incidence. The results show that contamination of DF during injection is a risk that can be reduced by modifying skin prep and injection practices. PMID:28332593

  3. Contamination of DNase Preparations Confounds Analysis of the Role of DNA in Alum-Adjuvanted Vaccines.

    Science.gov (United States)

    Noges, Laura E; White, Janice; Cambier, John C; Kappler, John W; Marrack, Philippa

    2016-08-15

    Aluminum salt (alum) adjuvants have been used for many years as adjuvants for human vaccines because they are safe and effective. Despite its widespread use, the means by which alum acts as an adjuvant remains poorly understood. Recently, it was shown that injected alum is rapidly coated with host chromatin within mice. Experiments suggested that the host DNA in the coating chromatin contributed to alum's adjuvant activity. Some of the experiments used commercially purchased DNase and showed that coinjection of these DNase preparations with alum and Ag reduced the host's immune response to the vaccine. In this study, we report that some commercial DNase preparations are contaminated with proteases. These proteases are responsible for most of the ability of DNase preparations to inhibit alum's adjuvant activity. Nevertheless, DNase somewhat reduces responses to some Ags with alum. The effect of DNase is independent of its ability to cleave DNA, suggesting that alum improves CD4 responses to Ag via a pathway other than host DNA sensing. Copyright © 2016 by The American Association of Immunologists, Inc.

  4. Principal Component Analysis with Contaminated Data: The High Dimensional Case

    CERN Document Server

    Xu, Huan; Mannor, Shie

    2010-01-01

    We consider the dimensionality-reduction problem (finding a subspace approximation of observed data) for contaminated data in the high dimensional regime, where the number of observations is of the same magnitude as the number of variables of each observation, and the data set contains some (arbitrarily) corrupted observations. We propose a High-dimensional Robust Principal Component Analysis (HR-PCA) algorithm that is tractable, robust to contaminated points, and easily kernelizable. The resulting subspace has a bounded deviation from the desired one, achieves maximal robustness -- a breakdown point of 50% while all existing algorithms have a breakdown point of zero, and unlike ordinary PCA algorithms, achieves optimality in the limit case where the proportion of corrupted points goes to zero.

  5. Preparation of High Purity Amorphous Boron Powder

    Directory of Open Access Journals (Sweden)

    K.V. Tilekar

    2005-10-01

    Full Text Available Amorphous boron powder of high purity (92-94 % with a particle size of l-2 mm is preferred as a fuel for fuel-rich propellants for integrated rocket ramjets and for igniter formulations. Thispaper describes the studies on process optimisation of two processes, ie, oxidative roasting of boron (roasting boron in air and roasting boron with zinc in an inert medium for preparing high purity boron. Experimental studies reveal that roasting boron with zinc at optimised process conditions yields boron of purity more than 93 per cent, whereas oxidative roasting method yields boron of purity - 92 per cent. Oxidative roasting has comparative edge over the other processes owing to its ease of scale-up and simplicity

  6. Arsenic in tree rings at a highly contaminated site.

    Science.gov (United States)

    Cheng, Zhongqi; Buckley, Brendan M; Katz, Beth; Wright, William; Bailey, Richard; Smith, Kevin T; Li, Jingbo; Curtis, Ashley; Geen, Alexander van

    2007-04-15

    Arsenic concentrations were measured in annual rings, pith, bark, and leaves of five tree species (four genera) from a site highly contaminated with As in Vineland, New Jersey, and two nearby uncontaminated areas. The highest As concentrations were found in bark (0.68+/-0.89 mg/kg, n=16) and leaves (1.9+/-1.8 mg/kg, n=4) from the contaminated area. Tree-ring As levels from the contaminated area (0.28+/-0.15 mg/kg, n=32) were low but still considerably higher than those from the control areas (0.06+/-0.06 mg/kg, n=30). There is a generally positive relationship between soil and tree-ring As levels. The overall low uptake of As by trees contrasts with that of P, a chemical analog for As(V) in aerated soils. Much higher P concentration in sapwood than in heartwood indicates that P is exported into more recently formed wood during the conversion from sapwood to heartwood; this again is drastically different than the behavior of As which is present in sapwood and heartwood at comparable levels. Variable sapwood As concentrations observed in detailed radial profiles of tree-ring chemistry of a pine and an oak from the contaminated site suggest that As is most likely transported among multiple rings within the sapwood. Therefore, tree species for which sapwood is thin (e.g., oak as in this study) should be preferred for reconstructing the history of contamination of a site. Due to the possibility of lateral translocation between growth rings, further studies are necessary to understand within-tree As transport and storage before dendrochemistry can be confidently accepted for such applications.

  7. Absence of TGF-β Receptor Activation by Highly Purified hCG Preparations.

    Science.gov (United States)

    Koistinen, Hannu; Hautala, Laura; Koli, Katri; Stenman, Ulf-Håkan

    2015-12-01

    Recently, several LH/human chorionic gonadotropin (hCG) receptor-independent activities for hCG have been described, including activation of the TGF-β receptor (TGFβR) by hyperglycosylated hCG and stimulation of trophoblast invasion. Because the hCG concentrations used in these studies have been rather high, reflecting physiological hCG levels in pregnancy, even a minor contamination with growth factors, which act at very low concentrations, may be significant. Several commercial hCG preparations have been found to contain significant amounts of epidermal growth factor (EGF), which we also confirmed here. Furthermore, we found that some hCG preparations also contain significant amounts of TGF-β1. These hCG preparations were able to activate ERK1/2 in JEG-3 choriocarcinoma cells or TGFβR in mink lung epithelial cells transfected with a reporter gene for TGFβR activation. No such activation was found with highly purified hCG or its free β-subunit (hCGβ), irrespective of whether they were hyperglycosylated or not. Taken together, our results suggest that the growth factor contaminations in the hCG preparations can cause activation of TGFβR and, at least in JEG-3 cells, MAPK signaling. This highlights the importance to carefully control for potential contaminations and that highly purified hCG preparations have to be used for biological studies.

  8. Preparation of Silicon Carbide with High Properties

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to prepare silicon carbide with high properties, three kinds of SiC powders A, B, and C with different composition and two kinds of additives, which were Y2O3-Al2O3 system and Y2O3-La2O3 system, were used in this experiment. The properties of hot-pressed SiC ceramics were measured. With the same additives, different SiC powder resulted in different properties. On the other hand, with the same SiC powder, increasing the amount of the additive Y2O3-Al2O3 improved properties of SiC ceramics at room temperature, and increasing the amount of the additive Y2O3-La2O3 improved property SiC ceramics at elevated temperature. In addition, the microstructure of SiC ceramics was studied by scanning electron microscopy.

  9. Probiotic preparation reduces faecal water genotoxicity and cytotoxicity in chickens fed ochratoxin A contaminated feed (in vivo study).

    Science.gov (United States)

    Śliżewska, Katarzyna; Nowak, Adriana; Smulikowska, Stefania

    2016-01-01

    The aim of the present study was to assess the genotoxicity and cytotoxicity of the faecal water of chickens fed ochratoxin A (OTA) contaminated feed with and without probiotic preparation. The study was performed on 20 healthy female Ross broiler chickens divided into 4 groups: control chickens - fed with non-supplemented feed; PP chickens - fed feed supplemented with the probiotic preparation; OTA chickens - fed feed contaminated with 1 mg per kg of OTA; OTA + PP chickens - fed feed contaminated with 1 mg per kg of OTA and supplemented with the probiotic preparation. Faecal water samples were collected on the 35(th) day of life of chickens from each group. Genotoxicity was measured using the comet assay, and cytotoxicity by means of MTT tests. Mean DNA damage, measured as the percentage of DNA in the tails of the comets, was 8.50 ± 1.10 for chickens fed OTA at 1 mg/kg and 6.41 ± 0.67 in the controls. The supplementation of feed with the probiotic preparation decreased the extent of DNA damage to 4.74 ± 0.78. In the control group of chickens the average cytotoxicity was 38.5 ± 0.5 (in MTT), while in the probiotic preparation group (PP group) it was 31.8 ± 0.7 (in MTT). After supplementation of the feed with the probiotic preparation, the genotoxicity and cytotoxicity were decreased in a statistically significant manner.

  10. Recovery of Salmonella from internally and externally contaminated whole tomatoes using several different sample preparation procedures.

    Science.gov (United States)

    Wang, Hua; Gill, Vikas S; Irvin, Kari A; Byrd, Mindi; Bolger, Cathryn M; Zheng, Jie; Dickey, Erin E; Duvall, Robert E; Jacobson, Andrew P; Hammack, Thomas S

    2012-01-01

    Studies were conducted to determine the relative effectiveness of whole soak [current Bacteriological Analytical Manual-(BAM) Salmonella method], quarter, stomach, and blend methods for the recovery of Salmonella organisms from internally and externally contaminated tomatoes. Tomatoes were subjected to three inoculation methods: surface inoculation, internal inoculation by injection, and immersion with single Salmonella serovars. The inoculation levels ranged from 1 to 100 CFU/tomato for surface and injection inoculation or 1 to 100 CFU/mL for immersion inoculation. Tomatoes were held for 3 days after inoculation at 2-6 degrees C prior to initiation of analysis. Contaminated tomatoes were soaked, quartered, stomached, and blended in appropriate portions of Universal Pre-enrichment broth, and incubated for 24 h at 35 +/- 2 degrees C. The BAM Salmonella culture method was followed thereafter, and tomatoes were treated as a low-microbial-load food. The stomaching procedure was significantly (P < 0.05) more effective than the whole soak procedure for recovery of internalized Salmonella from tomatoes (by injection). The blending procedure was arithmetically superior to the stomaching procedure for detection of internalized Salmonella from tomatoes (by immersion). The blending procedure showed the same effectiveness as the whole soak procedure for the detection of Salmonella on tomato surfaces. Comparisons between test portion-to-broth ratios (weight to volume) showed that a 1:3 test portion-to-broth ratio had a better buffering capacity for blended tomatoes than a 1:1 test portion-to-broth ratio. It is recommended that the current whole soak BAM tomato sample preparation procedure be replaced with a blending procedure and a 1:3 test portion-to-broth ratio.

  11. Preparation of nano-TiO_2 photocatalysts and their decomposition activity in phenol-contaminated water

    Institute of Scientific and Technical Information of China (English)

    Xiao-yuan JIANG; Feng DU; Chun-xia GUO; Qiong YANG; Xiao-ming ZHENG

    2009-01-01

    TiO_2 was prepared by the hydrolyzation method in (NH_4)_2SO_4-modified TiCl4 solution, and TiO_2 photocatalysts were obtained by accelerating the precipitation of TiO_2 powder in a high-temperature water bath. The photocatalysts were characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Raman spectrum and UV-Vis (Ultraviolet-Visible) spectrometry techniques, and the photocatalytic activity in phenol-contaminated water was investigated. The results showed that photocatalysts calcined at 400 ℃ had a specific surface area of 138.2 m~2/g and an average particle size of 9 nm, and a significant increase in thermal stability of anatase phase. At the calcination temperature of 700 ℃, the crystal form of TiO_2 started to change into rutile (anatase: 97%, rutile: 3%). The activity of TiO_2 photocatalysts prepared with (NH_4)_2SO_4-modified TICl_4 solution was markedly stronger than that without (NH_4)_2SO_4-modified TiCl_4 solution. Maximal photocatalytic activity was observed at the mole ratio of Ti:(NH_4)_2SO_4=1:2, the water-bath temperature of 90 ℃ and the calcination temperature of 700 ℃.

  12. Evaluation of the Correct Use of Virkon Disinfectant in Reducing Bacterial Contamination of Platelets Components Prepared

    Directory of Open Access Journals (Sweden)

    M Sadeh

    2007-06-01

    Full Text Available Background: The purpose of the present study was to test the bactericidal effect of virkon on native species of bacteria seen in Iran by selecting a suitable concentration of virkon which would effectively reduce the level of environmental bacterial contamination including contamination of platelets components while following the exact instruction of the use of the disinfectant. Methods: This was an interferal -applied study. 160 samples were taken from laboratory benches, instruments and outer surface of blood component bags. The growing organisms were identified by using the McFarland constant standard protocols and the CFU/ml of bacteria was determined. Later all the laboratory benches and instruments involved in the preparation of platelet components were disinfected using (1% virkon solution. 101 samples were taken from disinfected areas and swabs were plated on to standard bacteriological media and plates were read. In addition, 1100 segments from platelet bags were separated and the platelet contents were plated and any bacterial growths were assessed using quality control department guidelines. Results: Out of 169 samples which were plated before disinfection by virkon following organisms were separated 56/8% gram positive b. (spore forming and without spores 96 samples, 59/8% gram positive cocci (staph. &strept. 101samples, 94/8% gram negative b. 159 samples, 82/2% gram negative cocci 139 samples. Post disinfection by virkon solution, out of 101 samples following organisms was separated: 24/8% gram positive b. 25 samples, 16/8% gram positive cocci 17 samples, 0% gram negative b. 5/9% gram negativ 6 samples, out of 1100 segment separated from platelets bags 4 samples (segments had bacterial growth (0036% 2 samples had gram positive b. growth and 2 samples had staph. Conclusion: By using correct concentration of virkon solution and following the exact manufactures instruction for use we were able to observe log reduction in bacterial

  13. Evaluation of environmental contaminations and occupational exposures involved in preparation of chemotherapeutic drugs.

    Science.gov (United States)

    Maeda, Shinichiro; Miyawaki, Koji; Matsumoto, Shoji; Oishi, Masako; Miwa, Yoshihiro; Kurokawa, Nobuo

    2010-06-01

    Many healthcare workers are concerned about the risk of occupational exposures to hazardous drugs. The Japanese Society of Hospital Pharmacists (JSHP) revised the "Guidelines for the Handling of Antineoplastic Drugs in Hospitals", however, the precautions and awareness of handling drugs varied in institutions. We assessed the levels of environmental contaminations in our hospital and urinary excretion of cyclophosphamide (CP) and ifosfamide (IF) in pharmacists and nurses. In environmental studies, we obtained samples by wiping the surfaces around two biological safety cabinets (BSCs) on eight days for four months. One BSC was equipped in hospital pharmacy and the other was equipped in an oncology ward, and used for preparing chemotherapeutic drugs for outpatients and for inpatients, respectively. We obtained the urine samples from 6 pharmacists and 2 nurses. We used solid phase extraction (SPE) as a convenient extraction procedure and liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) for the analysis of the samples. CP was detected on the working surfaces inside both BSCs, and detected at low levels on the back surfaces of the BSCs and at the working tables around the BSCs. IF over the LLOQ was not detected in both BSCs. CP and IF were not detected in all urine samples of pharmacists and nurses. Detection frequencies and amounts of these drugs were low levels, compared with previous reports in Japan, and our results showed that improving awareness about handling hazardous drugs could reduce the risk of the occupational exposures.

  14. Block containing contaminated ion exchange resins and preparation process. Bloc contenant des resines echangeuses d'ions contaminees et son procede de preparation

    Energy Technology Data Exchange (ETDEWEB)

    Kertesz, C.; Da Silva, P.

    1993-01-08

    The invention concerns a block containing contaminated ion exchange resins for storage in a repository. Ion exchange resins are incorporated, after water saturation, in a composite matrix made of hardened epoxide resin and cement chosen among Clinker slag cements and slag-ashes cements. The presence of cement in composite matrix allows to limit the temperature in such block below 63 degree C, during their preparation.

  15. PREPARATION OF HIGH PURITY MULLITE CERAMICS

    OpenAIRE

    Rodrigo, P.; Boch, P.

    1986-01-01

    Preparation of mullite ceramics by reaction-sintering of alumina silica shows the necessity of favoring densification over mullitisation. Different Al2O3/SiO2 ratios have been studied. The influence of additives, iron oxide and zirconium oxide, has been examined.

  16. Pulsed high voltage electric discharge disinfection of microbially contaminated liquids.

    Science.gov (United States)

    Anpilov, A M; Barkhudarov, E M; Christofi, N; Kop'ev, V A; Kossyi, I A; Taktakishvili, M I; Zadiraka, Y

    2002-01-01

    To examine the use of a novel multielectrode slipping surface discharge (SSD) treatment system, capable of pulsed plasma discharge directly in water, in killing micro-organisms. Potable water containing Escherichia coli and somatic coliphages was treated with pulsed electric discharges generated by the SSD. The SSD system was highly efficient in the microbial disinfection of water with a low energy utilization (eta approximately 10-4 kW h l-1). The SSD treatment was effective in the destruction of E. coli and its coliphages through the generation of u.v. radiation, ozone and free radicals. The non-thermal treatment method can be used for the eradication of micro-organisms in a range of contaminated liquids, including milk, negating the use of pasteurization. The method utilizes multipoint electric discharges capable of treating large volumes of liquid under static and flowing regimes.

  17. Stabilization of high mercury contaminated brine purification sludge.

    Science.gov (United States)

    Zhuang, J Ming; Lo, Tony; Walsh, Tony; Lam, Tak

    2004-09-10

    The highly leachable mercury contaminants of brine purification sludge (BPS) generated from the Hg-cell electrolysis process in chlorine production can be stabilized in the treatment procedure employing ferric-lignin derivatives (FLD) (Ligmet binder) and Portland cement (PC). The stabilization effectiveness has been examined by time-based multiple toxicity characteristic leaching procedure (TCLP) tests and sequential TCLP tests. In a period of 50 days, the multiple TCLP tests showed a variation of less than 90 microg l(-1) for the leachable mercury level, and the sequential TCLP tests for the same sample displayed a declining TCLP mercury level. Based on this study, the stabilization of approximately 2000 t of brine purification sludge has been successfully processed with the ferric-lignin derivatives treatment.

  18. A new method to prevent carry-over contaminations in two-step PCR NGS library preparations.

    Science.gov (United States)

    Seitz, Volkhard; Schaper, Sigrid; Dröge, Anja; Lenze, Dido; Hummel, Michael; Hennig, Steffen

    2015-11-16

    Two-step PCR procedures are an efficient and well established way to generate amplicon libraries for NGS sequencing. However, there is a high risk of cross-contamination by carry-over of amplicons from first to second amplification rounds, potentially leading to severe misinterpretation of results. Here we describe a new method able to prevent and/or to identify carry-over contaminations by introducing the K-box, a series of three synergistically acting short sequence elements. Our K-boxes are composed of (i) K1 sequences for suppression of contaminations, (ii) K2 sequences for detection of possible residual contaminations and (iii) S sequences acting as separators to avoid amplification bias. In order to demonstrate the effectiveness of our method we analyzed two-step PCR NGS libraries derived from a multiplex PCR system for detection of T-cell receptor beta gene rearrangements. We used this system since it is of high clinical relevance and may be affected by very low amounts of contaminations. Spike-in contaminations are effectively blocked by the K-box even at high rates as demonstrated by ultra-deep sequencing of the amplicons. Thus, we recommend implementation of the K-box in two-step PCR-based NGS systems for research and diagnostic applications demanding high sensitivity and accuracy.

  19. Preparation

    Directory of Open Access Journals (Sweden)

    M.M. Dardir

    2014-03-01

    Full Text Available Some hexanamide-mono and di-linoleniate esters were prepared by the reaction of linolenic acid and hexanamide (derived from the reaction of hexanoic acid and diethanolamine. The chemical structure for the newly prepared hexanamide-mono and di-linoleniate esters were elucidated using elemental analysis, (FTIR, H 1NMR and chemical ionization mass spectra (CI/Ms spectroscopic techniques. The results of the spectroscopic analysis indicated that they were prepared through the right method and they have high purity. The new prepared esters have high biodegradability and lower toxicity (environmentally friendly so they were evaluated as a synthetic-based mud (ester-based mud for oil-well drilling fluids. The evaluation included study of the rheological properties, filtration and thermal properties of the ester based-muds formulated with the newly prepared esters compared to the reference commercial synthetic-based mud.

  20. Use of on-site high performance liquid chromatography to evaluate the magnitude and extent of organic contaminants in aquifers

    Science.gov (United States)

    Goerlitz, D.F.; Franks, B.J.

    1989-01-01

    Appraisal of ground water contaminated by organic substances raises problems of difficult sample collection and timely chemical analysis. High-performance liquid chromatography was evaluated for on-site determination of specific organic contaminants in ground water samples and was used at three study sites. Organic solutes were determined directly in water samples, with little or no preparation, and usually in less than an hour after collection. This information improved sampling efficiency and was useful in screening for subsequent laboratory analysis. On two occasions, on-site analysis revealed that samples were undergoing rapid change, with major solutes being upgraded and alteration products being formed. In addition to sample stability, this technique proved valuable for monitoring other sampling factors such as compositional changes with respect to pumping, filtration, and cross contamination. -Authors

  1. Lead (II) detection and contamination routes in environmental sources, cookware and home-prepared foods from Zimatlán, Oaxaca, Mexico.

    Science.gov (United States)

    Villalobos, M; Merino-Sánchez, C; Hall, C; Grieshop, J; Gutiérrez-Ruiz, M E; Handley, M A

    2009-04-01

    An interdisciplinary investigation, involving environmental geochemists, epidemiologists, nurses, and anthropologists, was undertaken to determine the contamination source and pathway of an on-going outbreak of lead poisoning among migrants originating from Zimatlán, Oaxaca, Mexico and living in Seaside, California, and among their US-born children. An initial investigation in Seaside identified grasshopper foodstuff ("chapulines") imported from Mexico and consumed as snacks, as containing alarmingly high lead concentrations (up to 2300 mg/kg). The focus in the present work concentrates on the Oaxacan area of origin of the problem in Mexico, and two potential sources of contamination were investigated: wind-borne dusts from existing mine residues as potential contaminants of soil, plant, and fauna; and food preparation practices using lead-glazed ceramic cookware. Over a three year period, sampling was conducted in Oaxaca using community-level sampling and also targeted sampling with families of cases with lead poisoning in California. In addition to fresh field chapulines, we analyzed for total lead: soil, water, mine residues, and plant materials, both from areas adjacent to or at an abandoned waste site containing mine tailings, and from fields where chapulines are collected; foodstuffs gathered in community markets or in a food transport business; and foodstuffs and cookware gathered from relatives of case families in California. Also, selected new and used lead-glazed clay cookware was extracted for lead, using 0.02 M citric acid and with 4% acetic acid. The results indicated significant presence of lead in mine wastes, in specific foodstuffs, and in glazed cookware, but no extensive soil contamination was identified. In-situ experiments demonstrated that lead incorporation in food is made very efficient through grinding of spices in glazed cookware, with the combination of a harsh mechanical action and the frequent presence of acidic lime juice, but without

  2. Enviromental contaminants in Puget Sound fish - Histological Preparation and Chemical Analyses of Puget Sound Fish

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of a long-term contaminant-monitoring program of fish in Puget Sound and Georgia Basin, Washington Department of Fish and Wildlife (WDFW) and NWFSC have...

  3. Suppression of Cross Contamination in Multi-Layer Thin Film Prepared by Using Rotating Hexagonal Sputtering Cathode.

    Science.gov (United States)

    Park, Se Yeon; Choi, Bum Ho; Lee, Jong Ho

    2015-01-01

    In this study, single- and multi-layered thin films were prepared on a glass substrate using a newly developed rotating hexagonal sputtering cathode in a single chamber. The rotatinghexagonal sputtering cathode can install up to six different sputtering targets or six single targets in a cathode. Using the rotating hexagonal cathode, we prepared a single-layered AZO film and a multi-layer film to evaluate the performance of hexagonal gun. Cross-contamination, which is often observed in multi-layer thin film preparation, was suppressed to nearly zero by controlling process parameters and revising hardware. Energy-saving effects of five-layered glass were also verified by measuring the temperature.

  4. Measuring fuel contamination using high speed gas chromatography and cone penetration techniques

    Energy Technology Data Exchange (ETDEWEB)

    Farrington, S.P.; Bratton, W.L. [Applied Research Associates, Inc., South Royalton, VT (United States); Akard, M.L. [Chromatofast, Inc., Ann Arbor, MI (United States)] [and others

    1995-10-01

    Decision processes during characterization and cleanup of hazardous waste sites are greatly retarded by the turnaround time and expense incurred through the use of conventional sampling and laboratory analyses. Furthermore, conventional soil and groundwater sampling procedures present many opportunities for loss of volatile organic compounds (VOC) by exposing sample media to the atmosphere during transfers between and among sampling devices and containers. While on-site analysis by conventional gas chromatography can reduce analytical turnaround time, time-consuming sample preparation procedures are still often required, and the potential for loss of VOC is not reduced. This report describes the development of a high speed gas chromatography and cone penetration testing system which can detect and measure subsurface fuel contamination in situ during the cone penetration process.

  5. Biochar Preparation, Characterization, and Adsorptive Capacity and Its Effect on Bioavailability of Contaminants: An Overview

    Directory of Open Access Journals (Sweden)

    Obemah D. Nartey

    2014-01-01

    Full Text Available This paper provides an updated review on the subjects, the available alternative to produce biochar from biomass, quantification and characterization of biochar, the adsorptive capacity for the adsorption of contaminants, and the effect of biochar addition to agricultural soils on contaminant bioavailability. The property of biochar produced is much dependent upon the composition and type of biomass and the conditions at which biomass is carbonized. The physical and chemical characterizations are necessary to identify the basic structure and property of biochar and to predict its potential in various environmental application. Biochar is a promising alternative to remedy the soils contaminated with heavy metals and organic compounds through adsorption and immobilization due to its large surface area, charged surface, and functional groups. Overall, the bioavailability of heavy metals and organic compounds decreases when biochar is amended into soils.

  6. A novel method for sample preparation of fresh lung cancer tissue for proteomics analysis by tumor cell enrichment and removal of blood contaminants

    Directory of Open Access Journals (Sweden)

    Orre Lotta

    2010-02-01

    Full Text Available Abstract Background In-depth proteomics analyses of tumors are frequently biased by the presence of blood components and stromal contamination, which leads to large experimental variation and decreases the proteome coverage. We have established a reproducible method to prepare freshly collected lung tumors for proteomics analysis, aiming at tumor cell enrichment and reduction of plasma protein contamination. We obtained enriched tumor-cell suspensions (ETS from six lung cancer cases (two adenocarcinomas, two squamous-cell carcinomas, two large-cell carcinomas and from two normal lung samples. The cell content of resulting ETS was evaluated with immunocytological stainings and compared with the histologic pattern of the original specimens. By means of a quantitative mass spectrometry-based method we evaluated the reproducibility of the sample preparation protocol and we assessed the proteome coverage by comparing lysates from ETS samples with the direct lysate of corresponding fresh-frozen samples. Results Cytological analyses on cytospin specimens showed that the percentage of tumoral cells in the ETS samples ranged from 20% to 70%. In the normal lung samples the percentage of epithelial cells was less then 10%. The reproducibility of the sample preparation protocol was very good, with coefficient of variation at the peptide level and at the protein level of 13% and 7%, respectively. Proteomics analysis led to the identification of a significantly higher number of proteins in the ETS samples than in the FF samples (244 vs 109, respectively. Albumin and hemoglobin were among the top 5 most abundant proteins identified in the FF samples, showing a high contamination with blood and plasma proteins, whereas ubiquitin and the mitochondrial ATP synthase 5A1 where among the top 5 most abundant proteins in the ETS samples. Conclusion The method is feasible and reproducible. We could obtain a fair enrichment of cells but the major benefit of the method

  7. High risk of lead contamination for scavengers in an area with high moose hunting success.

    Science.gov (United States)

    Legagneux, Pierre; Suffice, Pauline; Messier, Jean-Sébastien; Lelievre, Frédérick; Tremblay, Junior A; Maisonneuve, Charles; Saint-Louis, Richard; Bêty, Joël

    2014-01-01

    Top predators and scavengers are vulnerable to pollutants, particularly those accumulated along the food chain. Lead accumulation can induce severe disorders and alter survival both in mammals (including humans) and in birds. A potential source of lead poisoning in wild animals, and especially in scavengers, results from the consumption of ammunition residues in the tissues of big game killed by hunters. For two consecutive years we quantified the level lead exposure in individuals of a sentinel scavenger species, the common raven (Corvus corax), captured during the moose (Alces alces) hunting season in eastern Quebec, Canada. The source of the lead contamination was also determined using stable isotope analyses. Finally, we identified the different scavenger species that could potentially be exposed to lead by installing automatic cameras targeting moose gut piles. Blood lead concentration in ravens increased over time, indicating lead accumulation over the moose-hunting season. Using a contamination threshold of 100 µg x L(-1), more than 50% of individuals were lead-contaminated during the moose hunting period. Lead concentration was twice as high in one year compared to the other, matching the number of rifle-shot moose in the area. Non-contaminated birds exhibited no ammunition isotope signatures. The isotope signature of the lead detected in contaminated ravens tended towards the signature from lead ammunition. We also found that black bears (Ursus americanus), golden eagles and bald eagles (Aquila chrysaetos and Haliaeetus leucocephalus, two species of conservation concern) scavenged heavily on moose viscera left by hunters. Our unequivocal results agree with other studies and further motivate the use of non-toxic ammunition for big game hunting.

  8. High risk of lead contamination for scavengers in an area with high moose hunting success.

    Directory of Open Access Journals (Sweden)

    Pierre Legagneux

    Full Text Available Top predators and scavengers are vulnerable to pollutants, particularly those accumulated along the food chain. Lead accumulation can induce severe disorders and alter survival both in mammals (including humans and in birds. A potential source of lead poisoning in wild animals, and especially in scavengers, results from the consumption of ammunition residues in the tissues of big game killed by hunters. For two consecutive years we quantified the level lead exposure in individuals of a sentinel scavenger species, the common raven (Corvus corax, captured during the moose (Alces alces hunting season in eastern Quebec, Canada. The source of the lead contamination was also determined using stable isotope analyses. Finally, we identified the different scavenger species that could potentially be exposed to lead by installing automatic cameras targeting moose gut piles. Blood lead concentration in ravens increased over time, indicating lead accumulation over the moose-hunting season. Using a contamination threshold of 100 µg x L(-1, more than 50% of individuals were lead-contaminated during the moose hunting period. Lead concentration was twice as high in one year compared to the other, matching the number of rifle-shot moose in the area. Non-contaminated birds exhibited no ammunition isotope signatures. The isotope signature of the lead detected in contaminated ravens tended towards the signature from lead ammunition. We also found that black bears (Ursus americanus, golden eagles and bald eagles (Aquila chrysaetos and Haliaeetus leucocephalus, two species of conservation concern scavenged heavily on moose viscera left by hunters. Our unequivocal results agree with other studies and further motivate the use of non-toxic ammunition for big game hunting.

  9. Remediation of a contaminated soil by Ni+2 after application of biochar prepared from de-inking paper sludge: Influence on enzyme activities

    Science.gov (United States)

    Gascó, G.; Paz-Ferreiro, J.; Araujo, F.; Guerrero, F.; Méndez, A.

    2012-04-01

    In recent years, an increasing proportion of recycled fibres are used in paper industries due to their important environmental and economical benefits. A ton of pulp produced from recycled paper requires 60% less energy to manufacture than a ton of bleached virgin kraft pulp [1]. However, removing the ink, clay, coatings and contaminants from waste paper in order to produce recycled paper creates large amounts of de-inking paper sludge (DPS). Nowadays, more than 200000 t of DPS were produced in Spain. DPS can be used as amendment due to their high organic matter [2] but the high C/N ratio and the heavy metal content can limit its use. For this reason, the preparation of biochar obtained from pyrolysis process for water remediation [3] and soil contaminated by heavy metal can be an valorisation alternative. The main objective of this work is to study the influence of the biochar application prepared from de-inking sewage sludge in the soil enzyme activities of a contaminated soil by Ni+2 at two different concentrations. For this reason, an incubation experiment was performed and several enzymatic activities (dehydrogenase, b-glucosidase, phosphomoesterase and arylsulphatase) were monitored. The study was completed studying the influence of the biochar application in plant-available metals from soil. [1] Thompson C.G. 1992. Recycled Papers. The Essential Guide, MIT Press, Cambridge. [2] Barriga S., Méndez A., Cámara J., Guerrero F., Gascó G. 2010. Agricultural valorisation of de-inking paper sludge as organic amendment in different soils: Thermal study. Journal of Thermal Analysis and Calorimetry 99: 981-986 [3] Méndez A., Barriga S., Fidalgo J.M., Gascó G. 2009. Adsorbent materials from paper industry waste materials and their use in Cu(II) removal from water. Journal of Hazardous Materials 165: 736-743.

  10. Preparation of petroleum-degrading bacterial agent and its application in remediation of contaminated soil in Shengli Oil Field, China.

    Science.gov (United States)

    Yu, Yang; Zhang, Wen; Chen, Guanhong; Gao, Yongchao; Wang, Jianing

    2014-01-01

    Two petroleum-degrading strains were screened from oil fields and denoted as SWH-1 (Bacillus subtilis) and SWH-2 (Sphingobacterium multivorum), which were used to ferment and prepare bacterial agent to remediate petroleum-contaminated sites in Shengli Oil Field in China. The optimal liquid fermentation medium and conditions were MgSO₄·7H₂O (0.5%), NaCl (0.5%), soybean dregs (3%), pH 7.0, culturing at 30 °C, and 220 r/min for 16 h. Peat was chosen as the bacterial carrier due to its ability of keeping microbial activity. Mixed fermented liquid was added into peat (1:2) and air-dried, and the bacterial agent was obtained. It was applied to the petroleum-contaminated soil, which was irrigated, tilled, and fertilized. The removal rate reached 67.7% after 2 months of remediation. During remediation, the quantity of indigenous bacteria varied a lot, while the inoculated bacteria remained stable; the dehydrogenase activity was at high levels and then decreased. Indigenous microorganisms, inoculated bacterial agent, nutrients, water, and soil permeability all played important roles. The study prepared an environment-friendly bacterial agent and established a set of bioremediation technique, which provided further insights into integration of fermentation engineering and soil remediation engineering.

  11. Polyacrylamide preparations for protection of water quality threatened by agricultural runoff contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Entry, J.A.; Sojka, R.E.; Watwood, Maribeth; Ross, Craig

    2002-12-01

    Polyacrylamide preparations show promise in reducing flow of sediments, nutrients and microorganisms from animal production facilities. - Waste streams associated with a variety of agricultural runoff sources are major contributors of nutrients, pesticides and enteric microorganisms to surface and ground waters. Water soluble anionic polyacrylamide (PAM) was found to be a highly effective erosion-preventing and infiltration-enhancing polymer, when applied at rates of 1-10 g m{sup -3} in furrow irrigation water. Water flowing from PAM treated irrigation furrows show large reductions in sediment, nutrients and pesticides. Recently PAM and PAM+CaO and PAM+Al(SO{sub 4}){sub 3} mixtures have been shown to filter bacteria, fungi and nutrients from animal wastewater. Low concentrations of PAM [175-350 g PAM ha{sup -1} as PAM or as PAM+CaO and PAM+Al(SO{sub 4}) mixture] applied to the soil surface, resulted in dramatic decreases (10 fold) of total, coliform and fecal streptococci bacteria in cattle, fish and swine wastewater leachate and surface runoff. PAM treatment also filtered significant amounts of NH{sub 4}, PO{sub 4} and total P in cattle and swine wastewater. This points to the potential of developing PAM as a water quality protection measure in combination with large-scale animal feeding operations. Potential benefits of PAM treatment of animal facility waste streams include: (1) low cost, (2) easy and quick application, (3) suitability for use with other pollution reduction techniques. Research on the efficacy of PAM for removal of protozoan parasites and viruses and more thorough assessment of PAM degradation in different soils is still needed to completely evaluate PAM treatment as an effective waste water treatment. We will present analysis and feasibility of using PAM, PAM+Al(SO{sub 4}){sub 3}, and PAM+CaO application for specific applications. Our results demonstrate their potential efficacy in reducing sediment, nutrients and microorganisms from animal

  12. High Yield Preparation Method of Thermally Stable Cellulose Nanofibers

    Directory of Open Access Journals (Sweden)

    Hongli Zhu

    2014-02-01

    Full Text Available The preparation of nanocellulose fibers (NFs is achieved through pretreating cellulose in a NaOH/urea/thiourea solution, and then defibrillating the fibers through ultrasonication, resulting in a high yield of 85.4%. Extensive work has been done to optimize the preparation parameters. The obtained NFs are about 30 nm in diameter with cellulose II crystal structure. They possess high thermal stability with an onset of thermal degradation at 270 °C and a maximum degradation temperature of 370 °C. Such NFs have potential applications in transistors and batteries with high thermal stability. NFs-H were obtained by homogenizing undefibrillated fibers separated from the preparation of NFs. NFs-H were also in cellulose II crystal form but with lower thermal stability due to low crystallinity. They can be applied to make highly transparent paper.

  13. Metal availability in a highly contaminated, dredged-sediment disposal site: Field measurements and geochemical modeling

    Energy Technology Data Exchange (ETDEWEB)

    Lions, Julie, E-mail: j.lions@brgm.f [BRGM, 3 Avenue Claude Guillemin, 45060 Orleans Cedex 2 (France); Centre National de Recherche sur les Sites et Sols Pollues, BP 537, 59505 Douai cedex (France); Guerin, Valerie; Bataillard, Philippe [BRGM, 3 Avenue Claude Guillemin, 45060 Orleans Cedex 2 (France); Centre National de Recherche sur les Sites et Sols Pollues, BP 537, 59505 Douai cedex (France); Lee, Jan van der [Mines ParisTech, Centre de Geosciences, 77305 Fontainebleau Cedex (France); Laboudigue, Agnes [Univ Lille Nord de France, F-59000 Lille (France); EMDouai, MPE-GCE, F-59500 Douai (France); Centre National de Recherche sur les Sites et Sols Pollues, BP 537, 59505 Douai cedex (France)

    2010-09-15

    Two complementary approaches were used to characterize arsenic and metal mobilizations from a dredged-sediment disposal site: a detailed field study combined with hydrogeochemical modeling. Contaminants in sediments were found to be mainly present as sulfides subject to oxidation. Secondary phases (carbonates, sulfates, (hydr)oxides) were also observed. Oxidative processes occurred at different rates depending on physicochemical conditions and contaminant contents in the sediment. Two distinct areas were identified on the site, each corresponding to a specific contaminant mobility behavior. In a reducing area, Fe and As were highly soluble and illustrated anoxic behavior. In well-oxygenated material, groundwater was highly contaminated in Zn, Cd and Pb. A third zone in which sediments and groundwater were less contaminated was also characterized. This study enabled us to prioritize remediation work, which should aim to limit infiltration and long-term environmental impact. - A detailed case study of metal behavior in a dredged-sediment disposal site combined with geochemical modeling.

  14. Preparing polished crystal slices with high precision orientation

    DEFF Research Database (Denmark)

    Mathiesen, S. Ipsen; Gerward, Leif; Pedersen, O.

    1974-01-01

    A polishing procedure is described which utilizes a high precision Laue technique for crystal orientation. Crystal slices with their final polished surfaces parallel to a crystallographic plane within 0.02° can be prepared. ©1974 The American Institute of Physics......A polishing procedure is described which utilizes a high precision Laue technique for crystal orientation. Crystal slices with their final polished surfaces parallel to a crystallographic plane within 0.02° can be prepared. ©1974 The American Institute of Physics...

  15. Preparation of spherical cobalt carbonate powder with high tap density

    Institute of Scientific and Technical Information of China (English)

    XIAO Jin; WANG Jian-feng; LIU Yong-dong; LI Jie; LIU Ye-xiang

    2006-01-01

    Spherical cobalt carbonate with high tap density, good crystallization and uniform particle size was prepared by controlled chemical crystal method using cobalt chloride and ammonium bicarbonate as cobalt source and precipitator. The effects of pH value and reaction time on crystallization and physical properties of cobalt carbonate were studied. The results show that the key factors influencing the preparation process of spherical cobalt carbonate with high tap density and good crystallization are how to control pH value (7.25 ± 0.05) and keep some reaction time (about 10 h). Co4O3 was prepared by sintering spherical morphology CoCO3 samples at varied temperatures. The results show that as the decomposition temperature increases, the as-obtained Co4O3 products with porous structure transform into polyhedral structure with glazed surface, and simultaneously the cobalt content and tap density increase. However, the specific surface area shows a trend of decrease.

  16. A novel method for sample preparation of fresh lung cancer tissue for proteomics analysis by tumor cell enrichment and removal of blood contaminants

    OpenAIRE

    Orre Lotta; Bergman Per; Elmberger Göran; Pernemalm Maria; De Petris Luigi; Lewensohn Rolf; Lehtiö Janne

    2010-01-01

    Abstract Background In-depth proteomics analyses of tumors are frequently biased by the presence of blood components and stromal contamination, which leads to large experimental variation and decreases the proteome coverage. We have established a reproducible method to prepare freshly collected lung tumors for proteomics analysis, aiming at tumor cell enrichment and reduction of plasma protein contamination. We obtained enriched tumor-cell suspensions (ETS) from six lung cancer cases (two ade...

  17. Preparation to the CMB Planck analysis : contamination due to the polarized galactic emission

    CERN Document Server

    Fauvet, L

    2010-01-01

    The Planck satellite experiment, which was launched the 14th of may 2009, will give an accurate measurement of the anisotropies of the Cosmic Microwave Background (CMB) in temperature and polarization. This measurement is polluted by the presence of diffuse galactic polarized foreground emissions. In order to obtain the level of accuracy required for the Planck mission it is necessary to deal with these foregrounds. In order to do this, have develloped and implemented coherent 3D models of the two main galactic polarized emissions : the synchrotron and thermal dust emissions. We have optimized these models by comparing them to preexisting data : the K-band of the WMAP data, the ARCHEOPS data at 353 GHz and the 408 MHz all-sky continuum survey. By extrapolation of these models at the frequencies where the CMB is dominant, we are able to estimate the contamination to the CMB Planck signal due to these polarized galactic emissions.

  18. Spectroscopic Determination of Trace Contaminants in High-Purity Oxygen

    Science.gov (United States)

    Hornung, Steven

    2013-01-01

    Oxygen used for extravehicular activities (EVAs) must be free of contaminants because a difference in a few tenths of a percent of argon or nitrogen content can mean significant reduction in available EVA time. These inert gases build up in the extravehicular mobility unit because they are not metabolized or scrubbed from the atmosphere. A prototype optical emission technique capable of detecting argon and nitrogen below 0.1% in oxygen has been developed. This instrument uses a glow discharge in reduced-pressure gas to produce atomic emission from the species present. Because the atomic emission lines from oxygen, nitrogen, and argon are discrete, and in many cases well-separated, trace amounts of argon and nitrogen can be detected in the ultraviolet and visible spectrum. This is a straightforward, direct measurement of the target contaminants, and may lend itself to a device capable of on-orbit verification of oxygen purity. A glow discharge is a plasma formed in a low-pressure (1 to 10 Torr) gas cell between two electrodes. Depending on the configuration, voltages ranging from 200 V and above are required to sustain the discharge. In the discharge region, the gas is ionized and a certain population is in the excited state. Light is produced by the transitions from the excited states formed in the plasma to the ground state. The spectrum consists of discrete, narrow emission lines for the atomic species, and broader peaks that may appear as a manifold for molecular species such as O2 and N2, the wavelengths and intensities of which are a characteristic of each atom. The oxygen emission is dominated by two peaks at 777 and 844 nm.

  19. Preparation of free-standing high quality mesoporous carbon membranes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiqing [ORNL; Liang, Chengdu [ORNL; Dai, Sheng [ORNL; Mahurin, Shannon Mark [ORNL; Zhu, Qing [ORNL

    2010-01-01

    Flat-sheet mesoporous carbon membranes with uniform pore size (e.g., 6.4 nm) and controllable thickness were prepared by pyrolysis of polymeric composite films, which were formed by self-assembly of phenolic resin and block copolymer under acidic conditions. Hexamethylenetetramine was selected as a solid cross-linker to control the rheology of polymeric carbon precursors so that the flat-sheet polymeric films could undergo carbonization without deformation, ensuring the preparation of mesoporous carbon membranes on a large scale with high quality. Gas transport properties through these mesoporous carbon membranes are also reported.

  20. Ultra-high vacuum compatible preparation chain for intermetallic compounds

    Science.gov (United States)

    Bauer, A.; Benka, G.; Regnat, A.; Franz, C.; Pfleiderer, C.

    2016-11-01

    We report the development of a versatile material preparation chain for intermetallic compounds, which focuses on the realization of a high-purity growth environment. The preparation chain comprises an argon glovebox, an inductively heated horizontal cold boat furnace, an arc melting furnace, an inductively heated rod casting furnace, an optically heated floating-zone furnace, a resistively heated annealing furnace, and an inductively heated annealing furnace. The cold boat furnace and the arc melting furnace may be loaded from the glovebox by means of a load-lock permitting to synthesize compounds starting with air-sensitive elements while handling the constituents exclusively in an inert gas atmosphere. All furnaces are all-metal sealed, bakeable, and may be pumped to ultra-high vacuum. We find that the latter represents an important prerequisite for handling compounds with high vapor pressure under high-purity argon atmosphere. We illustrate the operational aspects of the preparation chain in terms of the single-crystal growth of the heavy-fermion compound CeNi2Ge2.

  1. Characterization and Modeling of Contamination for Lyman Break Galaxy Samples at High Redshift

    Science.gov (United States)

    Vulcani, Benedetta; Trenti, Michele; Calvi, Valentina; Bouwens, Rychard; Oesch, Pascal; Stiavelli, Massimo; Franx, Marijn

    2017-02-01

    The selection of high-redshift sources from broadband photometry using the Lyman-break galaxy (LBG) technique is a well established methodology, but the characterization of its contamination for the faintest sources is still incomplete. We use the optical and near-IR data from four (ultra)deep Hubble Space Telescope legacy fields to investigate the contamination fraction of LBG samples at z∼ 5{--}8 selected using a color–color method. Our approach is based on characterizing the number count distribution of interloper sources, that is, galaxies with colors similar to those of LBGs, but showing detection at wavelengths shorter than the spectral break. Without sufficient sensitivity at bluer wavelengths, a subset of interlopers may not be properly classified, and contaminate the LBG selection. The surface density of interlopers in the sky gets steeper with increasing redshift of LBG selections. Since the intrinsic number of dropouts decreases significantly with increasing redshift, this implies increasing contamination from misclassified interlopers with increasing redshift, primarily by intermediate redshift sources with unremarkable properties (intermediate ages, lack of ongoing star formation and low/moderate dust content). Using Monte-Carlo simulations, we estimate that the CANDELS deep data have contamination induced by photometric scatter increasing from ∼ 2 % at z∼ 5 to ∼ 6 % at z∼ 8 for a typical dropout color ≥slant 1 mag, with contamination naturally decreasing for a more stringent dropout selection. Contaminants are expected to be located preferentially near the detection limit of surveys, ranging from 0.1 to 0.4 contaminants per arcmin2 at {J}125 = 30, depending on the field considered. This analysis suggests that the impact of contamination in future studies of z> 10 galaxies needs to be carefully considered.

  2. Production of highly pure einsteinium and fermium preparations

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, O.I.; Tarasov, V.A.; Zotov, E.A.; Baranov, A.Yu. [Federal State Unitary Enterprise ' ' State Scientific Center of Russian Federation Research Institute of Atomic Reactors' ' (Russian Federation)

    2004-07-01

    Highly pure einsteinium and fermium preparations are in increased demand due to the progress of the following fields of modern sciences: Fundamental and applied nuclear physics. Heavy actinides are necessary for detailed study of structure and decay of a nucleus, as well as initial material both for nuclear synthesis of new superheavy elements and for manufacturing radioactive radiation sources. Fundamental and applied radiochemistry. Einsteinium and fermium preparations are required to investigate chemical properties of these hard-to-obtain elements and to improve technology of their recovery and purification. Nuclear medicine. Biologically active compounds labeled with alpha- emitting einsteinium and fermium may be applied in prospect for a radioimmunotherapy of oncological diseases. The principal method of einsteinium and fermium production is irradiation of curium or californium isotopes in a high-flux nuclear reactor. Large-scale production of transplutonium elements at RIAR enables also to produce regularly significant quantities of einsteinium and fermium. (orig.)

  3. Controllable preparation of high-yield magnetic polymer latex.

    Science.gov (United States)

    Wu, Chun-Chao; Kong, Xiang-Ming; Yang, Hai-Long

    2011-09-01

    In order to overcome the low conversion and complex post-treatment, four different polymerization procedures were adopted to prepare the magnetic polymer latexes. The results clearly show that the strategy using magnetic emulsion template-dosage is the most effective and feasible. Based on the optimized procedure, various factors including the type of initiators such as oil soluble initiator, water soluble initiator, redox initiator system, crosslinking agent, functional monomers etc. were systematically studied. Magnetic polymer latex with high monomer conversion of 83% and high magnet content of 31.8% was successfully obtained. Besides, core-shell structured magnetic polymer latex with good film forming property was also prepared, which is promising for potential applications such as magnetic coatings and modification of cementitious materials with controlled polymer location.

  4. Advanced sample preparation for the molecular quantification of Staphylococcus aureus in artificially and naturally contaminated milk.

    Science.gov (United States)

    Aprodu, Iuliana; Walcher, Georg; Schelin, Jenny; Hein, Ingeborg; Norling, Börje; Rådström, Peter; Nicolau, Anca; Wagner, Martin

    2011-03-01

    Sample treatment is an essential element when using real-time PCR for quantification of pathogens directly on food samples. This study comparatively evaluated three different principles of sample treatment, i.e. immunomagnetic separation based on phage-derived cell wall binding molecules, matrix solubilization and flotation, in order to establish their suitability for quantifying low numbers of Staphylococcus aureus in milk. All three procedures succeeded to remove S. aureus from the milk matrix, either raw or pasteurized, and, as a result of the concentration of the target cells, minimized the effect of milk associated PCR inhibitors. Sample preparation based on immunomagnetic separation albeit of being user friendly, specific and rapid, failed to allow quantification of low and medium numbers (<10(4)CFU) of S. aureus. In a mastitic milk model cell wall binding domain (CBD)-based target cell extraction revealed results most closely matching those derived from culture-based quantification. Both matrix lysis and flotation allowed quantification of S. aureus at a level of 1-10 cells per ml. Both methods resulted in higher numbers of bacterial cell equivalents (bce) than plating could reveal. Since both methods harvest cells that have been subjected to either mechanical and chemical stresses before quantification, we concluded that the higher bce numbers resulted from a disaggregation of S. aureus clusters initially present in the inoculum. Conclusively, since likely each S. aureus cell of a toxigenic strain contributes to enterotoxin production, molecular quantification could provide an even more realistic impact assessment in outbreak investigations than plating does.

  5. Impact of drying surface and raking frequencies on mold incidence, ochratoxin A contamination, and cup quality during preparation of arabica and robusta cherries at the farm level.

    Science.gov (United States)

    Velmourougane, Kulandaivelu; Bhat, Rajeev; Gopinandhan, Thirukonda Nannier

    2010-11-01

    The aim of this study was to evaluate the impact and contribution of various drying surfaces (soil, cement, and tarpaulin) and raking frequencies (1 and 4/day) on the incidence of toxigenic molds, ochratoxin A (OTA) production, and on the overall cup quality during preparation of arabica and robusta coffee cherry in India. Two individual experimental batches (run 1 at the begin of harvest and run 2 at the end of harvest) were set up for the study. Results showed high incidence of molds in coffee dried on soil surface compared with that on cement and tarpaulin surfaces. In both arabica and robusta, OTA could be detected in Aspergillus ochraceus contaminated samples at the end of harvest. Raking of the cherries 4 times/day showed lower fungal incidence with no OTA levels detected. Overall, coffee cherry prepared by drying on tarpaulin surface with 4 rakings/day showed lower OTA and fungal incidence with good and acceptable cup quality, and this is recommended to be practiced at the farm level.

  6. Microwave-Assisted Preparation of High Entropy Alloys

    Directory of Open Access Journals (Sweden)

    Paolo Veronesi

    2015-10-01

    Full Text Available Microwaves at the ISM (Industrial, Scientific and Medical, reserved internationally frequency of 2450 or 5800 MHz have been used to prepare FeCoNiCuAl, FeCrNiTiAl and FeCoCrNiAl2.5 high entropy alloys by direct heating of pressed mixtures of metal powders. The aim of this work is to explore a new microwave-assisted near-net-shape technology, using a powder metallurgy approach for the preparation of high entropy alloys, able to overcome the limits of current melting technologies (defects formation or solid state ones (time demanding. High entropy alloy compositions have been selected so as to comprise at least one ferromagnetic element and one highly reactive couple, like Ni-Al, Ti-Al, Co-Al or Fe-Al. Results show that direct microwave heating of the powder precursors occurs, and further heating generation is favored by the ignition of exothermal reactions in the load. Microwaves have been applied both for the ignition and sustaining of such reactions, showing that by the proposed technique, it is possible to control the cooling rate of the newly-synthesized high entropy alloys. Results showed also that microwave heating in predominant magnetic field regions of the microwave applicator is more effective at controlling the cooling rate. The herein proposed microwave-assisted powder metallurgy approach is suitable to retain the shape of the load imparted during forming by uniaxial pressing. The homogeneity of the prepared high entropy alloys in all cases was good, without the dendritic segregation typical of arc melting, even if some partially-unreacted powders were detected in the samples.

  7. High-resolution radiation mapping to investigate FDNPP derived contaminant migration.

    Science.gov (United States)

    Martin, P G; Payton, O D; Yamashiki, Y; Richards, D A; Scott, T B

    2016-11-01

    As of March 2016, five years will have passed since the earthquake and ensuing tsunami that crippled the Fukushima Daiichi Nuclear Power Plant on Japan's eastern coast, resulting in the explosive release of significant quantities of radioactive material. Over this period, significant time and resource has been expended on both the study of the contamination as well as its remediation from the affected environments. Presented in this work is a high-spatial resolution foot-based radiation mapping study using gamma-spectrometry at a site in the contaminated Iitate Village; conducted at different times, seventeen months apart. The specific site selected for this work was one in which consistent uniform agriculture was observed across its entire extent. From these surveys, obtained from along the main northwest trending line of the fallout plume, it was possible to determine the rate of reduction in the levels of contamination around the site attributable to the natural decay of the radiocesium, remediation efforts or material transport. Results from the work suggest that neither the natural decay of radiocesium nor its downward migration through the soil horizons were responsible for the decline in measured activity levels across the site, with the mobilisation of contaminant species likely adhered to soil particulate and the subsequent fluvial transport responsible for the measurable reduction in activity. This transport of contaminant via fluvial methods has already well studied implications for the input of contaminant material entering the neighbouring Pacific Ocean, as well as the deposition of material along rivers within previously decontaminated areas.

  8. Energetic neutral contamination in modern high-current implanters

    Science.gov (United States)

    Cherekdjian, S.; Weisenberger, W.

    1991-04-01

    The presence of energetic neutrals in a high-current, high-energy implant can result in nonuniformities on a silicon wafer. A larger concern is when the energetic neutrals are not of the desired energy. This is a major consideration when designing ion implanters with pre- and post-acceleration stages. This paper investigates the levels of pre-accelerated boron neutrals present in a 180 kV boron implant. The machines investigated were a Nova 20A and an Applied Materials PI9000. A comparison of their vacuum systems and their ability to cope with photoresist batches and argon backfill are presented. Silicon wafers were mapped by four-point probe resistivity measurements and the levels of pre-accelerated neutrals were quantified by spreading resistance profiles (SRPs). It is clearly demonstrated that good uniformity on a bare silicon wafer is not an indicator of a clean ion beam. Even though it is well understood that this problem is vacuum-related, modern high-current implanters are still being built and marketed with improper vacuum isolation and insufficient pumping capability.

  9. Quantification of Campylobacter jejuni cross-contamination via hands, cutlery, and cutting board during preparation of a chicken fruit salad

    NARCIS (Netherlands)

    Verhoeff-Bakkenes, L.; Beumer, R.R.; Jonge, de R.; Leusden, van F.M.; Jong, de A.E.I.

    2008-01-01

    Using artificially contaminated chicken, the quantitative overall effect of Campylobacter jejuni cross-contamination, either via cutlery, cutting board, or hands, on the microbiological quality of a chicken salad was tested to identify the most critical transfer route. The end contamination level of

  10. Quantification of Campylobacter jejuni cross-contamination via hands, cutlery, and cutting board during preparation of a chicken fruit salad

    NARCIS (Netherlands)

    Verhoeff-Bakkenes, L.; Beumer, R.R.; Jonge, de R.; Leusden, van F.M.; Jong, de A.E.I.

    2008-01-01

    Using artificially contaminated chicken, the quantitative overall effect of Campylobacter jejuni cross-contamination, either via cutlery, cutting board, or hands, on the microbiological quality of a chicken salad was tested to identify the most critical transfer route. The end contamination level of

  11. Contamination Effects on Improving the Hydrogenation/Dehydrogenation Kinetics of Binary Magnesium Hydride/Titanium Carbide Systems Prepared by Reactive Ball Milling.

    Science.gov (United States)

    El-Eskandarany, M Sherif; Shaban, Ehab

    2015-10-10

    Ultrafine MgH₂ nanocrystalline powders were prepared by reactive ball milling of elemental Mg powders after 200 h of high-energy ball milling under a hydrogen gas pressure of 50 bar. The as-prepared metal hydride powders were contaminated with 2.2 wt. % of FeCr-stainless steel that was introduced to the powders upon using stainless steel milling tools made of the same alloy. The as-synthesized MgH₂ was doped with previously prepared TiC nanopowders, which were contaminated with 2.4 wt. % FeCr (materials of the milling media), and then ball milled under hydrogen gas atmosphere for 50 h. The results related to the morphological examinations of the fabricated nanocomposite powders beyond the micro-and nano-levels showed excellent distributions of 5.2 wt. % TiC/4.6 wt. % FeCr dispersoids embedded into the fine host matrix of MgH₂ powders. The as-fabricated nanocomposite MgH₂/5.2 wt. % TiC/4.6 wt. % FeCr powders possessed superior hydrogenation/dehydrogenation characteristics, suggested by the low value of the activation energy (97.74 kJ/mol), and the short time required for achieving a complete absorption (6.6 min) and desorption (8.4 min) of 5.51 wt. % H₂ at a moderate temperature of 275 °C under a hydrogen gas pressure ranging from 100 mbar to 8 bar. van't Hoff approach was used to calculate the enthalpy (DH) and entropy (DS) of hydrogenation for MgH₂, which was found to be -72.74 kJ/mol and 112.79 J/mol H₂/K, respectively. Moreover, van't Hoff method was employed to calculate the DH and DS of dehydrogenation, which was found to be 76.76 kJ/mol and 119.15 J/mol H₂/K, respectively. This new nanocomposite system possessed excellent absorption/desorption cyclability of 696 complete cycles, achieved in a cyclic-life-time of 682 h.

  12. Contamination Effects on Improving the Hydrogenation/Dehydrogenation Kinetics of Binary Magnesium Hydride/Titanium Carbide Systems Prepared by Reactive Ball Milling

    Science.gov (United States)

    El-Eskandarany, M. Sherif; Shaban, Ehab

    2015-01-01

    Ultrafine MgH2 nanocrystalline powders were prepared by reactive ball milling of elemental Mg powders after 200 h of high-energy ball milling under a hydrogen gas pressure of 50 bar. The as-prepared metal hydride powders were contaminated with 2.2 wt. % of FeCr-stainless steel that was introduced to the powders upon using stainless steel milling tools made of the same alloy. The as-synthesized MgH2 was doped with previously prepared TiC nanopowders, which were contaminated with 2.4 wt. % FeCr (materials of the milling media), and then ball milled under hydrogen gas atmosphere for 50 h. The results related to the morphological examinations of the fabricated nanocomposite powders beyond the micro-and nano-levels showed excellent distributions of 5.2 wt. % TiC/4.6 wt. % FeCr dispersoids embedded into the fine host matrix of MgH2 powders. The as-fabricated nanocomposite MgH2/5.2 wt. % TiC/4.6 wt. % FeCr powders possessed superior hydrogenation/dehydrogenation characteristics, suggested by the low value of the activation energy (97.74 kJ/mol), and the short time required for achieving a complete absorption (6.6 min) and desorption (8.4 min) of 5.51 wt. % H2 at a moderate temperature of 275 °C under a hydrogen gas pressure ranging from 100 mbar to 8 bar. van’t Hoff approach was used to calculate the enthalpy (∆H) and entropy (∆S) of hydrogenation for MgH2, which was found to be −72.74 kJ/mol and 112.79 J/mol H2/K, respectively. Moreover, van’t Hoff method was employed to calculate the ΔH and ΔS of dehydrogenation, which was found to be 76.76 kJ/mol and 119.15 J/mol H2/K, respectively. This new nanocomposite system possessed excellent absorption/desorption cyclability of 696 complete cycles, achieved in a cyclic-life-time of 682 h. PMID:28793606

  13. Contamination Effects on Improving the Hydrogenation/Dehydrogenation Kinetics of Binary Magnesium Hydride/Titanium Carbide Systems Prepared by Reactive Ball Milling

    Directory of Open Access Journals (Sweden)

    M. Sherif El-Eskandarany

    2015-10-01

    Full Text Available Ultrafine MgH2 nanocrystalline powders were prepared by reactive ball milling of elemental Mg powders after 200 h of high-energy ball milling under a hydrogen gas pressure of 50 bar. The as-prepared metal hydride powders were contaminated with 2.2 wt. % of FeCr-stainless steel that was introduced to the powders upon using stainless steel milling tools made of the same alloy. The as-synthesized MgH2 was doped with previously prepared TiC nanopowders, which were contaminated with 2.4 wt. % FeCr (materials of the milling media, and then ball milled under hydrogen gas atmosphere for 50 h. The results related to the morphological examinations of the fabricated nanocomposite powders beyond the micro-and nano-levels showed excellent distributions of 5.2 wt. % TiC/4.6 wt. % FeCr dispersoids embedded into the fine host matrix of MgH2 powders. The as-fabricated nanocomposite MgH2/5.2 wt. % TiC/4.6 wt. % FeCr powders possessed superior hydrogenation/dehydrogenation characteristics, suggested by the low value of the activation energy (97.74 kJ/mol, and the short time required for achieving a complete absorption (6.6 min and desorption (8.4 min of 5.51 wt. % H2 at a moderate temperature of 275 C under a hydrogen gas pressure ranging from 100 mbar to 8 bar. van’t Hoff approach was used to calculate the enthalpy (DH and entropy (DS of hydrogenation for MgH2, which was found to be 72.74 kJ/mol and 112.79 J/mol H2/K, respectively. Moreover, van’t Hoff method was employed to calculate the DH and DS of dehydrogenation, which was found to be 76.76 kJ/mol and 119.15 J/mol H2/K, respectively. This new nanocomposite system possessed excellent absorption/desorption cyclability of 696 complete cycles, achieved in a cyclic-life-time of 682 h.

  14. Multi-Channel High-Tc SQUID Detection System for Metallic Contaminants

    Science.gov (United States)

    Kitamura, Yoshihiro; Hatsukade, Yoshimi; Tanaka, Saburo; Ohtani, Takeyoshi; Suzuki, Shuichi

    Finding ultra-small metallic contaminants is a big issue for manufacturers of lithium-ion batteries nowadays. Therefore, we have developed high-Tc SQUID systems for detection of such fine magnetic metallic contaminants. In this paper, we constructed an eight channel high-Tc SQUID gradiometer system for inspection of a sheet electrode of a lithium ion battery with width of about 70 mm. By this system, a small iron ball of about 30 μm in diameter was successfully detected. It is shown that this system has a detectable range of 70 mm in width. These results suggest that the system is a promising tool for the detection of the contaminants in lithium ion batteries.

  15. Comparison of preparative HPLC/MS and preparative SFC techniques for the high-throughput purification of compound libraries.

    Science.gov (United States)

    Searle, Philip A; Glass, Keithney A; Hochlowski, Jill E

    2004-01-01

    A diverse set of 16 high-throughput organic synthesis libraries, consisting of 48 samples per library, has been purified by both preparative supercritical fluid chromatography (SFC) and preparative high-performance liquid chromatography (HPLC). This paper details the relative effectiveness of these two purification techniques in terms of success, yield, and purity of final product.

  16. High pressure processing as an intervention for raw virus-contaminated shellfish

    Science.gov (United States)

    Over the past 7 years, the USDA ARS Seafood Safety Laboratory has evaluated the potential use of high pressure processing (HPP) as a processing strategy for virus-contaminated shellfish. HPP can inactivate hepatitis A virus, (HAV), the human norovirus surrogates feline calicivirus and murine norovi...

  17. Preparation for football competition at moderate to high altitude.

    Science.gov (United States)

    Gore, C J; McSharry, P E; Hewitt, A J; Saunders, P U

    2008-08-01

    Analysis of approximately 100 years of home-and-away South American World Cup matches illustrate that football competition at moderate/high altitude (>2000 m) favors the home team, although this is more than compensated by the likelihood of sea-level teams winning at home against the same opponents who have descended from altitude. Nevertheless, the home team advantage at altitudes above approximately 2000 m may reflect that traditionally, teams from sea level or low altitude have not spent 1-2 weeks acclimatizing at altitude. Despite large differences between individuals, in the first few days at high altitude (e.g. La Paz, 3600 m) some players experience symptoms of acute mountain sickness (AMS) such as headache and disrupted sleep, and their maximum aerobic power (VO2max) is approximately 25% reduced while their ventilation, heart rate and blood lactate during submaximal exercise are elevated. Simulated altitude for a few weeks before competition at altitude can be used to attain partial ventilatory acclimation and ameliorated symptoms of AMS. The variety of simulated altitude exposures usually created with enriched nitrogen mixtures of air include resting or exercising for a few hours per day or sleeping approximately 8 h/night in hypoxia. Preparation for competition at moderate/high altitude by training at altitude is probably superior to simulated exposure; however, the optimal duration at moderate/high altitude is unclear. Preparing for 1-2 weeks at moderate/high altitude is a reasonable compromise between the benefits associated with overcoming AMS and partial restoration of VO2max vs the likelihood of detraining.

  18. Highly Efficient Enzymatic Preparation of Daidzein in Deep Eutectic Solvents

    Directory of Open Access Journals (Sweden)

    Qi-Bin Cheng

    2017-01-01

    Full Text Available Daidzein, which is scarce in nature, has gained significant attention due to its superior biological activity and bioavailability compared with daidzin. So far, it has been widely used in the medicine and health care products industries. The enzymatic approach for the preparation of daidzein has prevailed, benefitted by its high efficiency and eco-friendly nature. Our present research aimed at providing a preparation method of daidzein by enzymatic hydrolysis of daidzin in a new “green” reaction medium-deep eutectic solvents (DESs. Herein, the DESs were screened via evaluating enzyme activity, enzyme stability and the substrate solubility, and the DES (ChCl/EG 2:1, 30 vol % was believed to be the most appropriate co-solvent to improve the bioconversion efficiency. Based on the yield of daidzein, response surface methodology (RSM was employed to model and optimize the reaction parameters. Under these optimum process conditions, the maximum yield of 97.53% was achieved and the purity of daidzein crude product reached more than 70%, which is more efficient than conversions in DESs-free buffer. Importantly, it has been shown that DESs medium could be reused for six batches of the process with a final conversion of above 50%. The results indicated that this procedure could be considered a mild, environmentally friendly, highly efficient approach to the economical production of daidzein, with a simple operation process and without any harmful reagents being involved.

  19. Community-based risk assessment of water contamination from high-volume horizontal hydraulic fracturing.

    Science.gov (United States)

    Penningroth, Stephen M; Yarrow, Matthew M; Figueroa, Abner X; Bowen, Rebecca J; Delgado, Soraya

    2013-01-01

    The risk of contaminating surface and groundwater as a result of shale gas extraction using high-volume horizontal hydraulic fracturing (fracking) has not been assessed using conventional risk assessment methodologies. Baseline (pre-fracking) data on relevant water quality indicators, needed for meaningful risk assessment, are largely lacking. To fill this gap, the nonprofit Community Science Institute (CSI) partners with community volunteers who perform regular sampling of more than 50 streams in the Marcellus and Utica Shale regions of upstate New York; samples are analyzed for parameters associated with HVHHF. Similar baseline data on regional groundwater comes from CSI's testing of private drinking water wells. Analytic results for groundwater (with permission) and surface water are made publicly available in an interactive, searchable database. Baseline concentrations of potential contaminants from shale gas operations are found to be low, suggesting that early community-based monitoring is an effective foundation for assessing later contamination due to fracking.

  20. Library preparation for highly accurate population sequencing of RNA viruses

    Science.gov (United States)

    Acevedo, Ashley; Andino, Raul

    2015-01-01

    Circular resequencing (CirSeq) is a novel technique for efficient and highly accurate next-generation sequencing (NGS) of RNA virus populations. The foundation of this approach is the circularization of fragmented viral RNAs, which are then redundantly encoded into tandem repeats by ‘rolling-circle’ reverse transcription. When sequenced, the redundant copies within each read are aligned to derive a consensus sequence of their initial RNA template. This process yields sequencing data with error rates far below the variant frequencies observed for RNA viruses, facilitating ultra-rare variant detection and accurate measurement of low-frequency variants. Although library preparation takes ~5 d, the high-quality data generated by CirSeq simplifies downstream data analysis, making this approach substantially more tractable for experimentalists. PMID:24967624

  1. Preparation of Highly Purified Stearidonic Acid from Echium Oil via an Enzymatic Method Combined with Preparative High Performance Liquid Chromatography.

    Science.gov (United States)

    Baik, Ji Yeon; Kim, Nam Ho; Oh, Se-Wook; Kim, In-Hwan

    2015-01-01

    Stearidonic acid (SDA), an n-3 polyunsaturated fatty acid (PUFA), can be obtained from plant origin oils and it can be a good source of PUFA for vegetarians. SDA can be easily converted to longer PUFA such as docosahexaenoic acid and eicosapentaenoic acid. Highly purified stearidonic acid (SDA) was prepared successfully from echium oil via an enzymatic method combined with preparative high performance liquid chromatography. In the 1(st) step, SDA enrichment was accomplished using Candida rugosa lipase and 39.5% of SDA was obtained in the fatty acid fraction. Subsequently, the 1(st) reaction mixture was used for the 2(nd) enzymatic esterification without any separation process. The 2(nd) esterification was conducted for further SDA enrichment in a packed-bed reactor using Lipozyme RM IM from Rhizomucor miehei and the SDA content increased in a very short residence time. Ethanol was selected as an appropriate alcohol to react as an acyl receptor, and the other conditions for SDA enrichment were optimized at 20°C of temperature, and 1:4 of molar ratio (i.e., fatty acid to ethanol). Under these conditions, 51.6% of SDA was obtained in the fatty acid fraction after a residence time of 15 min. Finally, highly purified SDA (purity, >99%) was obtained by prep-HPLC using the SDA-rich fraction obtained from the two-step lipase-catalyzed esterification.

  2. Tissue contaminants and associated transcriptional response in trout liver from high elevation lakes of Washington

    Science.gov (United States)

    Moran, P.W.; Aluru, N.; Black, R.W.; Vijayan, M.M.

    2007-01-01

    The consistent cold temperatures and large amount of precipitation in the Olympic and Cascade ranges of Washington State are thought to enhance atmospheric deposition of contaminants. However, little is known about contaminant levels in organisms residing in these remote high elevation lakes. We measured total mercury and 28 organochlorine compounds in trout collected from 14 remote lakes in the Olympic, Mt. Rainer, and North Cascades National Parks. Mercury was detected in trout from all lakes sampled (15 to 262 ??g/kg ww), while two organochlorines, total polychlorinated biphenyls (tPCB) and dichlorodiphenyldichloroethylene (DDE), were also detected in these fish tissues (<25 ??g/kg ww). In sediments, organochlorine levels were below detection, while median total and methyl mercury were 30.4 and 0.34 ??g/ kg dry weight (ww), respectively. Using fish from two lakes, representing different contaminant loading levels (Wilcox lake: high; Skymo lake: low), we examined transcriptional response in the liver using a custom-made low-density targeted rainbow trout cDNA microarray. We detected significant differences in liver transcriptional response, including significant changes in metabolic, endocrine, and immune-related genes, in fish collected from Wilcox Lake compared to Skymo Lake. Overall, our results suggest that local urban areas contribute to the observed contaminant patterns in these high elevation lakes, while the transcriptional changes point to a biological response associated with exposure to these contaminants in fish. Specifically, the gene expression pattern leads us to hypothesize a role for mercury in disrupting the metabolic and reproductive pathways in fish from high elevation lakes in western Washington. ?? 2007 American Chemical Society.

  3. Recovery and Growth Potential of Listeria monocytogenes in Temperature Abused Milkshakes Prepared from Naturally Contaminated Ice Cream Linked to a Listeriosis Outbreak.

    Science.gov (United States)

    Chen, Yi; Allard, Emma; Wooten, Anna; Hur, Minji; Sheth, Ishani; Laasri, Anna; Hammack, Thomas S; Macarisin, Dumitru

    2016-01-01

    The recovery and growth potential of Listeria monocytogenes was evaluated in three flavors of milkshakes (vanilla, strawberry, and chocolate) that were prepared from naturally contaminated ice cream linked to a listeriosis outbreak in the U.S. in 2015, and were subsequently held at room temperature for 14 h. The average lag phase duration of L. monocytogenes was 9.05 h; the average generation time was 1.67 h; and the average population level increase per sample at 14 h was 1.14 log CFU/g. Milkshake flavors did not significantly affect these parameters. The average lag phase duration of L. monocytogenes in milkshakes with initial contamination levels ≤ 3 CFU/g (9.50 h) was significantly longer (P 3 CFU/g (8.60 h). The results highlight the value of using samples that are contaminated with very low levels of L. monocytogenes for recovery and growth evaluations. The behavior of L. monocytogenes populations in milkshakes prepared from naturally contaminated ice cream linked to the listeriosis outbreak should be taken into account when performing risk based analysis using this outbreak as a case study.

  4. Recovery and growth potential of Listeria monocytogenes in temperature abused milkshakes prepared from naturally contaminated ice cream linked to a listeriosis outbreak

    Directory of Open Access Journals (Sweden)

    Yi eChen

    2016-05-01

    Full Text Available The recovery and growth potential of Listeria monocytogenes was evaluated in three flavors of milkshakes (vanilla, strawberry, and chocolate that were prepared from naturally contaminated ice cream linked to a listeriosis outbreak in the U.S. in 2015, and were subsequently held at room temperature for 14 hours. The average lag phase duration of L. monocytogenes was 9.05 h; the average generation time was 1.67 h; and the average level increase per sample at 14 h was 1.15 log CFU/g. Milkshake flavors did not significantly affect these parameters. The average lag phase duration of L. monocytogenes in milkshakes with initial contamination levels ≤ 3 CFU/g (9.50 h was significantly longer (P 3 CFU/g (8.60 h. The results highlight the value of using samples that are contaminated with very low levels of L. monocytogenes for recovery and growth evaluations. The behavior of L. monocytogenes populations in milkshakes prepared from naturally contaminated ice cream linked to the listeriosis outbreak should be taken into account when performing risk based analysis using this outbreak as a case-study.

  5. Semisolid Slurry Preparation of Die Steel with High Chromium Content

    Institute of Scientific and Technical Information of China (English)

    MAO Wei-min; ZHAO Ai-min; ZHANG Li-juan; ZHONG Xue-you

    2004-01-01

    The semisolid slurry preparation of die steels Cr12 and Cr12MoV with high chromium content was studied. The results show that the semisolid slurry of both steels with solid of 40 %-60 % can be made by electromagnetic stirring method and is easy to be discharged from the bottom little hole of the stirring chamber. The sizes of the spherical primary austenite in the slurry of die steels Cr12 and Cr12MoV are 50-100 μm and 80-150 μm, respectively. The homogeneous temperature field and solute field for both steel melts are obtained. The strong temperature fluctuation in the melt with many fine primary austenite grains occurs and the remelting of the secondary arm roots at the same time is accelerated because of the electromagnetic stirring. These are the most important reasons for deposition of spherical primary austenite grains.

  6. Preparation of Garlic Powder with High Allicin Content

    Institute of Scientific and Technical Information of China (English)

    LI Yu; XU Shi-ying

    2007-01-01

    Garlic powder with high allicin content was prepared using microwave-vacuum and vacuum drying as well as microencapsulation to protect alliinase activity throughout the stomach and improve the ratio of alliin transforming into allicin. The results showed that the optimal drying condition was 376.1 W for 3 min, 282.1 W for 3 min, 188 W for 9 min, and 94 W for 3 min. The thiosulfinates retention after drying was 90.2%. Following drying, the garlic powder was microencapsulated by modified fluidized bed technique. Scanning electron microscope revealed good integrity and core materials that were embedded in the microcapsules. Studies on the release kinetics of microencapsulated garlic granulates in vitro using simulated intestinal fluid indicated that release of garlic powder could be controlled in the intestine by passing stomach conditions.

  7. The risk of river pollution due to washout from contaminated floodplain water bodies during high floods

    Science.gov (United States)

    Lyubimova, Tatyana; Lepikhin, Anatoly; Parshakova, Yanina; Tiunov, Alexey

    2016-04-01

    Today, the potential impact of extremely high floods, which in the last years have become a rather frequent weather-related disaster, is the problem of primary concern. In studies of the potential impact of floods the emphasis is placed first of all on the estimation of possible flood zones and the analysis of the flow regimes in these zones. However, in some cases the hydrochemical parameters related to changes in the chemical composition of water are more important than the hydraulic parameters. It is generally believed that the higher is the flow rate, the more intensive is the process of dissolution, i.e. the lower is the concentration of limiting contaminants in water. However, this statement is valid provided that flooding does not activate new sources of water pollution such as contaminated floodplain water bodies located in the vicinity of water supply systems. Being quite reliable and safe at small and moderate discharges, in the case of extremely high level of river waters they become intensive sources of water pollution, essentially limiting the water consumption schedule for downstream water consumers. It should be noted that compared to the well-studied mechanisms of waste discharge due to failure of hydraulic engineering structures by flood waves, the mechanisms of pollutant washout from the contaminated floodplain water bodies by the flood waves is still poorly understood. We analyze the impacts of such weather-related events on the quality of water in the water intake system, taking as an example, the section of the Vyatka River located in the Prikamskaya lowland of the Russian Federation. The risk of river pollution due to washout from the contaminated floodplain water bodies during high floods is studied by hydrodynamical modeling in the framework of combined approach using one-, two- and three-dimensional hydrodynamic models are implemented and by in situ measurements. It is shown that during high floods the removal of pollutants from the

  8. PREPARATION OF HIGH THERMAL EXPANSION COEFFICIENT PORCELAINS FUSED TO METALS

    Institute of Scientific and Technical Information of China (English)

    J.P. Yang; J.Q. Wu

    2003-01-01

    Usually the thermal expansion coefficients (TEC) of metals are higher than that of porcelains. In order to match the TECs in the case of coating porcelains on metals, high TEC porcelains are needed. In this research, the high TEC phase leucite(KAlSi2 O6) in the high TEC porcelain was prepared by sol-gel method. The crystal size of leucite made by sol-gel is about 77nm through controlling the process parameters. The process from xerogel to leucite was investigated by means of DSC (differential scanning calorimetry), TG (thermogravimetry), XRD ( X-ray diffraction) and IR(infrared absorption spectrum). Leucite had been detected after the gel was treated at 900°C, this formation temperature is about 250°C lower than that of melting method.The porcelain made from 50% of the leucite powder and 50%o of low fused temperature frit has an average TEC of 19.2× 10-6/° C from room temperature to 450°C, which is much higher than the common porcelains.

  9. High spatial resolution image object classification for terrestrial oil spill contamination mapping in West Siberia

    Science.gov (United States)

    Hese, S.; Schmullius, C.

    2009-04-01

    This work is a part of the OSCaR pilot study (Oil Spill Contamination mapping in Russia). A synergetic concept for an object based and multi temporal mapping and classification system for terrestrial oil spill pollution using a test area in West Siberia is presented. An object oriented image classification system is created to map contaminated soils, vegetation and changes in the oil exploration well infrastructure in high resolution data. Due to the limited spectral resolution of Quickbird data context information and image object structure are used as additional features building a structural object knowledge base for the area. The distance of potentially polluted areas to industrial land use and infrastructure objects is utilized to classify crude oil contaminated surfaces. Additionally the potential of Landsat data for dating of oil spill events using change indicators is tested with multi temporal Landsat data from 1987, 1995 and 2001. OSCaR defined three sub-projects: (1) high resolution mapping of crude oil contaminated surfaces, (2) mapping of industrial infrastructure change, (3) dating of oil spill events using multi temporal Landsat data. Validation of the contamination mapping results has been done with field data from Russian experts provided by the Yugra State University in Khanty-Mansiyskiy. The developed image object structure classification system has shown good results for the severely polluted areas with good overall classification accuracy. However it has also revealed the need for direct mapping of hydrocarbon substances. Oil spill event dating with Landsat data was very much limited by the low spatial resolution of Landsat TM 5 data, small scale character of oil spilled surfaces and limited information about oil spill dates.

  10. Mercury speciation in highly contaminated soils from chlor-alkali plants using chemical extractions.

    Science.gov (United States)

    Neculita, Carmen-Mihaela; Zagury, Gérald J; Deschênes, Louise

    2005-01-01

    A four-step novel sequential extraction procedure (SEP) was developed to assess Hg fractionation and mobility in three highly contaminated soils from chlor-alkali plants (CAPs). The SEP was validated using a certified reference material (CRM) and pure Hg compounds. Total, volatile, and methyl Hg concentrations were also determined using single extractions. Mercury was separated into four fractions defined as water-soluble (F1), exchangeable (F2) (0.5 M NH4Ac-EDTA and 1 M CaCl2 were tested), organic (F3) (successive extractions with 0.2 M NaOH and CH3COOH 4% [v/v]), and residual (F4) (HNO3 + H2SO4 + HClO4). The soil characterization revealed extremely contaminated (295 +/- 18 to 11 500 +/- 500 mg Hg kg(-1)) coarse-grained sandy soils having an alkaline pH (7.9-9.1), high chloride concentrations (5-35 mg kg(-1)), and very low organic carbon content (0.00-18.2 g kg(-1)). Methyl Hg concentrations were low (0.2-19.3 microg kg(-1)) in all soils. Sequential extractions indicated that the majority of the Hg was associated with the residual fraction (F4). In Soils 1 and 3, however, high percentages (88-98%) of the total Hg were present as volatile Hg. Therefore, in these two soils, a high proportion of volatile Hg was present in the residual fraction. The nonresidual fraction (F1 + F2 + F3) was most abundant in Soil 1 (14-42%), suggesting a higher availability of Hg in this soil. The developed and validated SEP was reproducible and efficient for highly contaminated samples. Recovery ranged between 93 and 98% for the CRM and 70 and 130% for the CAP-contaminated soils.

  11. Influence of the contaminant size on the thermal damage of optical mirrors used in high energy laser system

    Science.gov (United States)

    Han, Kai; Song, Rui; Xu, Xiaojun; Liu, Zejin

    2016-09-01

    The laser induced damage is a troublesome issue in the application of optical mirrors, which is related to the robustness of the whole laser system. There are two types of mechanisms about the damage of optical mirrors: thermal effect and field effect, which are responsible for the high energy continuous wave (cw) laser induced damage and the high power pulsed laser induced damage, respectively. Under the irradiation of high energy laser, the contaminant on the mirror surface absorbs the laser energy and converts the laser energy to heat. With the heat accumulating, the optical mirror is likely to fuse and even be totally destroyed. The temperature of the contaminant was measured when it was irradiated by a cw high energy laser with power intensity 3.3kW/cm2. It is found that the contaminant achieves thermal equilibrium in a few seconds and then the temperature stays at 1700K. A physical model was established to describe the process of the thermal equilibrium. The influence of the contaminant size on the thermal damage of the optical mirror was studied theoretically. The results show that the contaminant size plays an important role in the thermal damage of the optical mirror. Only when the contaminant size is smaller than a critical size ( 10μm), the contaminant may reach thermal equilibrium and the optical mirror works well in the high energy laser system. If the contaminant size is quite large (mirror will damage under the irradiation of high energy laser.

  12. Preparation of an Ultrafine Rebamipide Ophthalmic Suspension with High Transparency.

    Science.gov (United States)

    Matsuda, Takakuni; Hiraoka, Shogo; Urashima, Hiroki; Ogura, Ako; Ishida, Tatsuhiro

    2017-01-01

    A 2% commercially available, milky-white, rebamipide micro-particle suspension is used to treat dry eyes, and it causes short-term blurring of the patient's vision. In the current study, to improve the transparency of a rebamipide suspension, we attempted to obtain a clear rebamipide suspension by transforming the rebamipide particles to an ultrafine state. In the initial few efforts, various rebamipide suspensions were prepared using a neutralizing crystallization method with additives, but the suspensions retained their opaque quality. However, as a consequence of several critical improvements in the neutralizing crystallization methods such as selection of additives for crystallization, process parameters during crystallization, the dispersion method, and dialysis, we obtained an ultrafine rebamipide suspension (2%) that was highly transparent (transmittance at 640 nm: 59%). The particle size and transparency demonstrated the fewest level of changes at 25°C after 3 years, compared to initial levels. During that period, no obvious particle sedimentation was observed. The administration of this ultrafine rebamipide suspension (2%) increased the conjunctival mucin, which was comparable to the commercially available micro-particle suspension (2%). The corneal and conjunctival concentration of rebamipide following ocular administration of the ultrafine suspension was slightly higher than that of the micro-particle suspension. The ultrafine rebamipide suspension (eye-drop formulation) with a highly transparent ophthalmic clearness should improve a patient's QOL by preventing even a shortened period of blurred vision.

  13. Method validation for 243 pesticides and environmental contaminants in meats and poultry by tandem mass spectrometry coupled to low-pressure gas chromatography and ultra high-performance liquid chromatography

    Science.gov (United States)

    An easy and reliable high-throughput analysis method was developed and validated for 192 diverse pesticides and 51 environmental contaminants (13 PCB congeners, 14 PAHs, 7 PBDE congeners, and 17 novel flame retardants) in cattle, swine, and poultry muscle. Sample preparation was based on the “quick,...

  14. Metagenomic Approach Reveals Variation of Microbes with Arsenic and Antimony Metabolism Genes from Highly Contaminated Soil

    Science.gov (United States)

    Luo, Jinming; Bai, Yaohui; Liang, Jinsong; Qu, Jiuhui

    2014-01-01

    Microbes have great potential for arsenic (As) and antimony (Sb) bioremediation in heavily contaminated soil because they have the ability to biotransform As and Sb to species that have less toxicity or are more easily removed. In this study, we integrated a metagenomic method with physicochemical characterization to elucidate the composition of microbial community and functional genes (related to As and Sb) in a high As (range from 34.11 to 821.23 mg kg−1) and Sb (range from 226.67 to 3923.07 mg kg−1) contaminated mine field. Metagenomic analysis revealed that microbes from 18 phyla were present in the 5 samples of soil contaminated with high As and Sb. Moreover, redundancy analysis (RDA) of the relationship between the 18 phyla and the concentration of As and Sb demonstrated that 5 phyla of microbes, i.e. Actinobacteria, Firmicutes, Nitrospirae, Tenericutes and Gemmatimonadetes were positively correlated with As and Sb concentration. The distribution, diversity and abundance of functional genes (including arsC, arrA, aioA, arsB and ACR3) were much higher for the samples containing higher As and Sb concentrations. Based on correlation analysis, the results showed a positive relationship between arsC-like (R2 = 0.871) and aioA-like (R2 = 0.675) gene abundance and As concentration, and indicated that intracellular As(V) reduction and As(III) oxidation could be the dominant As detoxification mechanism enabling the microbes to survive in the environment. This study provides a direct and reliable reference on the diversity of microbial community and functional genes in an extremely high concentration As- and Sb-contaminated environment. PMID:25299175

  15. Metagenomic approach reveals variation of microbes with arsenic and antimony metabolism genes from highly contaminated soil.

    Science.gov (United States)

    Luo, Jinming; Bai, Yaohui; Liang, Jinsong; Qu, Jiuhui

    2014-01-01

    Microbes have great potential for arsenic (As) and antimony (Sb) bioremediation in heavily contaminated soil because they have the ability to biotransform As and Sb to species that have less toxicity or are more easily removed. In this study, we integrated a metagenomic method with physicochemical characterization to elucidate the composition of microbial community and functional genes (related to As and Sb) in a high As (range from 34.11 to 821.23 mg kg-1) and Sb (range from 226.67 to 3923.07 mg kg-1) contaminated mine field. Metagenomic analysis revealed that microbes from 18 phyla were present in the 5 samples of soil contaminated with high As and Sb. Moreover, redundancy analysis (RDA) of the relationship between the 18 phyla and the concentration of As and Sb demonstrated that 5 phyla of microbes, i.e. Actinobacteria, Firmicutes, Nitrospirae, Tenericutes and Gemmatimonadetes were positively correlated with As and Sb concentration. The distribution, diversity and abundance of functional genes (including arsC, arrA, aioA, arsB and ACR3) were much higher for the samples containing higher As and Sb concentrations. Based on correlation analysis, the results showed a positive relationship between arsC-like (R2 = 0.871) and aioA-like (R2 = 0.675) gene abundance and As concentration, and indicated that intracellular As(V) reduction and As(III) oxidation could be the dominant As detoxification mechanism enabling the microbes to survive in the environment. This study provides a direct and reliable reference on the diversity of microbial community and functional genes in an extremely high concentration As- and Sb-contaminated environment.

  16. Circumstances associated with the contamination of food by aflatoxin in a high primary liver cancer area.

    Science.gov (United States)

    Van Rensburg, S J; Kirsipuu, A; Coutinho, L P; Van Der Watt, J J

    1975-05-24

    The variable incidence of primary liver cancer has been shown to be related to the average daily intake of aflatoxin in various parts of the world. This study was made to detect and report strategic points of contamination of foodstuffs in the region with the highest known incidence of liver cancer. Methods of food production, harvesting, storage and preparation were examined, and defects which promote fungus growth on food were found at each stage. Most meals consisted of a single dish with three basic ingredients -- a protein, bulk carbohydrate and green vegetables. Groundnuts were the main source of protein, but were also the main cause of aflatoxin contamination, since casual traditional methods of agriculture are not suited to the production of this exotic crop. Aflatoxin production appears to occur in the main sources of carbohydrate, such as cassava and maize, during storage. Leaves of various kinds provide substitutes for green vegetables and common methods of handling the crop promote fungal growth. Western-type foods had a particularly low aflatoxin content, or were free of it. Education and economic opportunities external to the subsistence economy structure are contributing to the westerisation of some living habits, a process believed to be responsible for the observed decrease in the incidence of primary liver cancer. Current knowledge indicates that a pertinent but simple educational programme could further markedly reduce the incidence of the disease.

  17. Reversible Electrochemical Sensor for Detection of High-Charge Density Polyanion Contaminants in Heparin.

    Science.gov (United States)

    Lester, Jacob; Chandler, Timothy; Gemene, Kebede L

    2015-11-17

    We present a simple, rapid, and inexpensive electrochemical sensor based on a reversible pulsed chronopotentiometric polyanion-selective membrane electrode for the detection and quantification of oversulfated chondroitin sulfate (OSCS) and other high charge-density polyanions that could potentially be used to adulterate heparin. The membrane is free of ion exchanger and is formulated with plasticized poly(vinyl chloride) (PVC) and an inert lipophilic salt, tridodecylmethylammonium-dinonylnaphthaline sulfonate (TDMA-DNNS). The neutral salt is used to reduce membrane resistance and to ensure reversibility of the sensor. More importantly, TDMA(+) is used as the recognition element for the polyanions. Here an anodic galvanostatic current pulse is applied across the membrane to cause the extraction of the polyanions from the sample into the membrane and potential is measured at the sample-membrane interface. The measured electromotive force (emf) is proportional to the concentration and the charge density of the polyanions. High charge-density polyanion contaminants and impurities in heparin can be detected using this method since the overall equilibrium potential response of polyions increases with increasing charge density of the polyions. Here, first the potential response of pure heparin is measured at a saturation concentration, the concentration beyond which further addition of heparin does not produce a change in potential response. Then the potential response of heparin tainted with different quantities of the high charge-density contaminant is measured at a fixed total polyion concentration (heparin concentration + contaminant concentration). The latter gives a greater negative potential response due to the presence of the high charge-density contaminant. The increase in the negative potential response can be used for detection and quantification of high charge-density contaminants in heparin. We demonstrate here that 0.3% (w/w) OSCS as well as 0.1% (w

  18. High-Throughput Preparation of New Photoactive Nanocomposites.

    Science.gov (United States)

    Conterosito, Eleonora; Benesperi, Iacopo; Toson, Valentina; Saccone, Davide; Barbero, Nadia; Palin, Luca; Barolo, Claudia; Gianotti, Valentina; Milanesio, Marco

    2016-06-08

    New low-cost photoactive hybrid materials based on organic luminescent molecules inserted into hydrotalcite (layered double hydroxides; LDH) were produced, which exploit the high-throughput liquid-assisted grinding (LAG) method. These materials are conceived for applications in dye-sensitized solar cells (DSSCs) as a co-absorbers and in silicon photovoltaic (PV) panels to improve their efficiency as they are able to emit where PV modules show the maximum efficiency. A molecule that shows a large Stokes' shift was designed, synthesized, and intercalated into LDH. Two dyes already used in DSSCs were also intercalated to produce two new nanocomposites. LDH intercalation allows the stability of organic dyes to be improved and their direct use in polymer melt blending. The prepared nanocomposites absorb sunlight from UV to visible and emit from blue to near-IR and thus can be exploited for light-energy management. Finally one nanocomposite was dispersed by melt blending into a poly(methyl methacrylate)-block-poly(n-butyl acrylate) copolymer to obtain a photoactive film.

  19. Surface Sampling Collection and Culture Methods for Escherichia coli in Household Environments with High Fecal Contamination.

    Science.gov (United States)

    Exum, Natalie G; Kosek, Margaret N; Davis, Meghan F; Schwab, Kellogg J

    2017-08-22

    Empiric quantification of environmental fecal contamination is an important step toward understanding the impact that water, sanitation, and hygiene interventions have on reducing enteric infections. There is a need to standardize the methods used for surface sampling in field studies that examine fecal contamination in low-income settings. The dry cloth method presented in this manuscript improves upon the more commonly used swabbing technique that has been shown in the literature to have a low sampling efficiency. The recovery efficiency of a dry electrostatic cloth sampling method was evaluated using Escherichia coli and then applied to household surfaces in Iquitos, Peru, where there is high fecal contamination and enteric infection. Side-by-side measurements were taken from various floor locations within a household at the same time over a three-month period to compare for consistency of quantification of E. coli bacteria. The dry cloth sampling method in the laboratory setting showed 105% (95% Confidence Interval: 98%, 113%) E. coli recovery efficiency off of the cloths. The field application demonstrated strong agreement of side-by-side results (Pearson correlation coefficient for dirt surfaces was 0.83 (p samples (Pearson (0.53, p method can be utilized in households with high bacterial loads using either continuous (quantitative) or categorical (semi-quantitative) data. The standardization of this low-cost, dry electrostatic cloth sampling method can be used to measure differences between households in intervention and non-intervention arms of randomized trials.

  20. High bacterial biodiversity increases degradation performance of hydrocarbons during bioremediation of contaminated harbor marine sediments.

    Science.gov (United States)

    Dell'Anno, Antonio; Beolchini, Francesca; Rocchetti, Laura; Luna, Gian Marco; Danovaro, Roberto

    2012-08-01

    We investigated changes of bacterial abundance and biodiversity during bioremediation experiments carried out on oxic and anoxic marine harbor sediments contaminated with hydrocarbons. Oxic sediments, supplied with inorganic nutrients, were incubated in aerobic conditions at 20 °C and 35 °C for 30 days, whereas anoxic sediments, amended with organic substrates, were incubated in anaerobic conditions at the same temperatures for 60 days. Results reported here indicate that temperature exerted the main effect on bacterial abundance, diversity and assemblage composition. At higher temperature bacterial diversity and evenness increased significantly in aerobic conditions, whilst decreased in anaerobic conditions. In both aerobic and anaerobic conditions, biodegradation efficiencies of hydrocarbons were significantly and positively related with bacterial richness and evenness. Overall results presented here suggest that bioremediation strategies, which can sustain high levels of bacterial diversity rather than the selection of specific taxa, may significantly increase the efficiency of hydrocarbon degradation in contaminated marine sediments.

  1. Special Physical Preparation of High Schoolers for Performing Parkour Exercises

    Directory of Open Access Journals (Sweden)

    Т. М. Кравчук

    2017-03-01

    Full Text Available The objective is to ground and develop a methodology of special physical preparation of high schoolers for performing parkour elements, and to experimentally verify its effectiveness. Materials and methods: Kharkiv secondary school No. 84 served as the grounds for the study. The participants in the study were boys aged 15-17: 10 persons – in the reference group, and 10 persons – in the experimental group. The methods of the study: theoretical analysis and collation of scientific and methodological literature; pedagogical observation; video recording; biomechanical analysis; talks with experts; pedagogical experiment; mathematical and statistical methods of research materials processing. Results: The experimental group showed positive improvement in the balancing technique from 3.5 points before the experiment to 6.3 after the experiment (p < 0.05; a considerable increase in points in the jumping technique, including jumps onto the wall bars hand-gripping its edge, jumps into landing with a roll, and jumps over obstacle – from 2.9, 4.2 and 4.6 points respectively at the beginning of the experiment to 5.9, 6.7 and 7.8 points respectively after the experiment (p < 0.05; positive significant improvement in the wall bars running results – from 3.2 points at the beginning of the experiment to 6.7 after the experiment (p < 0.05. Conclusions: special sets of exercises have been designed to develop and improve these abilities in parkour, and the effectiveness of the designed methodology has been experimentally verified. The study has proved that, when used in physical training of high schoolers, the special sets of exercises intended to develop parkourists’ speed, strength and coordination abilities contribute to a significant increase in the level of the technique of execution of the main parkour elements.

  2. Fowl play? Forensic environmental assessment of alleged discharge of highly contaminated effluent from a chicken slaughterhouse

    Science.gov (United States)

    Harvey, P.; Taylor, M. P.; Handley, H. K.

    2016-12-01

    Multiple lines of geochemical and biological evidence are applied to identify and fingerprint the nature and source of alleged contamination emanating from a chicken slaughterhouse on the urban fringe of Sydney, Australia. The slaughterhouse has a long history of alleged environmental misconduct. The impact of the facility on catchment source waters by the slaughterhouse has been the subject of controversy. The facility owner has persistently denied breach of their licence condition and maintains it is `a very environmentally conscious operation'. The disputed nature of the possible sources of discharges and its contaminants required a detailed forensic environmental assessment. Water samples collected from off-site discharge points associated with the facility show highly elevated concentrations of faecal coliforms (max 68,000 cfu), ammonia-N (51,000 µg/L), total nitrogen (98,000 µg/L) and phosphorous (32,000 µg/L). Upstream and adjacent watercourses were markedly less contaminated. Water discharge points associated with the slaughterhouse and natural catchment runoff were sampled for arsenic speciation, including assessment for the organoarsenic compound Roxarsone. Roxarsone is used as a chicken growth promoter. Water draining the slaughterhouse facility contained concentrations around 10 times local background levels. The Roxarsone compound was not detected in any waters, but inorganic arsenic, As(V), was present in all waters with the greatest concentrations in waters draining from the slaughterhouse. The environmental evidence was compiled over a series of discharges events and presented to the NSW EPA. Subsequent to receipt of the data supported by their own investigations, the NSW EPA mandated that the slaughterhouse be subject to a pollution reduction program. The efficacy of the pollution reduction program to stem the release of highly contaminated effluent is currently subject to ongoing investigation using a suite of water chemistry measures including

  3. One step preparation of spherical drug particles by contamination-free dry milling technique with corn starch beads.

    Science.gov (United States)

    Niwa, Toshiyuki; Yoshida, Maria; Hayashi, Naoko; Kondo, Keita

    2017-08-07

    The novel dry milling technique has been developed by using a mechanical powder processor for improving the dissolution properties of poorly water-soluble drugs. It was found that the drug crystals were well pulverized by co-processing with fine particles of corn starch (CS). The morphological observation and particle size evaluation revealed that the processed products formed the composite particles with ordered-mixed structure, having double-layered particles with a core of CS and a coating layer of phenytoin (Phe), as a model drug. This result suggested that the drug crystals were selectively micronized and the resultant miniaturized Phe particles were adhered/fixed on the surface of un-milled CS particles. The mechanical characteristics detected by the indentation test assumed that the brittle Phe crystals sandwiched between elastic CS particles would be successfully crushed down by high shearing stress in the processor. The newly-established dispersion-sedimentation test indicated that the fine Phe particles were immediately detached from the composite particles in aqueous phase, constructing the suspension. The dissolution behavior from the processed particles was found to be improved and strongly dependent on the size and amount of detached Phe particles. Such milling and ordered-mixturization have been also successfully done by using recrystallized larger Phe particles than 100μm. These results would propose the contamination-free dry milling technique without using hard milling balls or beads. The mechanism of the current milling and ordered-mixing phenomena is also provided in this report. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Method for the preparation of high surface area high permeability carbons

    Science.gov (United States)

    Lagasse, R.R.; Schroeder, J.L.

    1999-05-11

    A method for preparing carbon materials having high surface area and high macropore volume to provide high permeability. These carbon materials are prepared by dissolving a carbonizable polymer precursor, in a solvent. The solution is cooled to form a gel. The solvent is extracted from the gel by employing a non-solvent for the polymer. The non-solvent is removed by critical point drying in CO{sub 2} at an elevated pressure and temperature or evaporation in a vacuum oven. The dried product is heated in an inert atmosphere in a first heating step to a first temperature and maintained there for a time sufficient to substantially cross-link the polymer material. The cross-linked polymer material is then carbonized in an inert atmosphere. 3 figs.

  5. Method for the preparation of high surface area high permeability carbons

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, Robert R. (Albuquerque, NM); Schroeder, John L. (Albuquerque, NM)

    1999-05-11

    A method for preparing carbon materials having high surface area and high macropore volume to provide high permeability. These carbon materials are prepared by dissolving a carbonizable polymer precursor, in a solvent. The solution is cooled to form a gel. The solvent is extracted from the gel by employing a non-solvent for the polymer. The non-solvent is removed by critical point drying in CO.sub.2 at an elevated pressure and temperature or evaporation in a vacuum oven. The dried product is heated in an inert atmosphere in a first heating step to a first temperature and maintained there for a time sufficient to substantially cross-link the polymer material. The cross-linked polymer material is then carbonized in an inert atmosphere.

  6. Surface preparation for ALD of High-k dielectrics on indium gallium arsenide

    Science.gov (United States)

    Melitz, Wilhelm

    The key for a successful gate-first process is when subsequent processing steps cannot degrade the semiconductor, the dielectric, or the oxide-semiconductor interfaces. For silicon, the only commercial ALD high-k fabrication process, which avoids processing induced damage, is a replacement gate process (a type of gate-last process). While preparing silicon for gate-last processing is straightforward, the key to a gate-last process for III-V semiconductors is the order and cleanliness of the III-V channel prior to dielectric deposition. Aggressive oxide thickness reduction (equivalent oxide thickness, or EOT, scaling) is needed to fabricate small gate length devices with small subthreshold swings. Furthermore, aggressive EOT scaling requires a very high uniform ALD nucleation density, with no pinholes due to surface contaminants. The key barrier to solving a very practical problem is a surface chemistry challenge: develop a chemical process which removes nearly all air induced defects and contaminants and leaves the III-V surface flat and electrically active for high nucleation density ALD gate oxide deposition, which unpins the Fermi level. The following study uses scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) to observe the removal of the oxide layer and restoration of the clean InGaAs surface reconstruction with atomic hydrogen cleaning, allowing for a gate-last or replacement-gate process. Along with surface cleaning STM and STS was used to characterize the initial passivation of InGaAs surfaces via ALD of trimethyl aluminum (TMA). The substrate temperature and initial surface reconstruction was critical to forming an unpinned passivation layer with a high nucleation density. A method was developed to use Kelvin probe force microscopy (KPFM) as a tool for insightful feedback on the electrostatics of scaled MOSFET devices. KPFM is a unique technique for providing two-dimensional potential profiles inside a working device. A

  7. Measurement of radioactive contamination in the high-resistivity silicon CCDs of the DAMIC experiment

    CERN Document Server

    Aguilar-Arevalo, A; Bertou, X; Bole, D; Butner, M; Cancelo, G; Vázquez, A Castañeda; Chavarria, A E; Neto, J R T de Mello; Dixon, S; D'Olivo, J C; Estrada, J; Moroni, G Fernandez; Torres, K P Hernández; Izraelevitch, F; Kavner, A; Kilminster, B; Lawson, I; Liao, J; López, M; Molina, J; Moreno-Granados, G; Pena, J; Privitera, P; Sarkis, Y; Scarpine, V; Schwarz, T; Haro, M Sofo; Tiffenberg, J; Machado, D Torres; Trillaud, F; You, X; Zhou, J

    2015-01-01

    We present measurements of radioactive contamination in the high-resistivity silicon charge-coupled devices (CCDs) used by the DAMIC experiment to search for dark matter particles. Novel analysis methods, which exploit the unique spatial resolution of CCDs, were developed to identify $\\alpha$ and $\\beta$ particles. Uranium and thorium contamination in the CCD bulk was measured through $\\alpha$ spectroscopy, with an upper limit on the $^{238}$U ($^{232}$Th) decay rate of 5 (15) kg$^{-1}$ d$^{-1}$ at 95% CL. We also searched for pairs of spatially correlated electron tracks separated in time by up to tens of days, as expected from $^{32}$Si-$^{32}$P or $^{210}$Pb-$^{210}$Bi sequences of $\\beta$ decays. The decay rate of $^{32}$Si was found to be $80^{+110}_{-65}$ kg$^{-1}$ d$^{-1}$ (95% CI). An upper limit of $\\sim$35 kg$^{-1}$ d$^{-1}$ (95% CL) on the $^{210}$Pb decay rate was obtained independently by $\\alpha$ spectroscopy and the $\\beta$ decay sequence search. These levels of radioactive contamination are su...

  8. Extensive arsenic contamination in high-pH unconfined aquifers in the Indus Valley

    Science.gov (United States)

    Podgorski, Joel E.; Eqani, Syed Ali Musstjab Akber Shah; Khanam, Tasawar; Ullah, Rizwan; Shen, Heqing; Berg, Michael

    2017-01-01

    Arsenic-contaminated aquifers are currently estimated to affect ~150 million people around the world. However, the full extent of the problem remains elusive. This is also the case in Pakistan, where previous studies focused on isolated areas. Using a new data set of nearly 1200 groundwater quality samples throughout Pakistan, we have created state-of-the-art hazard and risk maps of arsenic-contaminated groundwater for thresholds of 10 and 50 μg/liter. Logistic regression analysis was used with 1000 iterations, where surface slope, geology, and soil parameters were major predictor variables. The hazard model indicates that much of the Indus Plain is likely to have elevated arsenic concentrations, although the rest of the country is mostly safe. Unlike other arsenic-contaminated areas of Asia, the arsenic release process in the arid Indus Plain appears to be dominated by elevated-pH dissolution, resulting from alkaline topsoil and extensive irrigation of unconfined aquifers, although pockets of reductive dissolution are also present. We estimate that approximately 50 million to 60 million people use groundwater within the area at risk, with hot spots around Lahore and Hyderabad. This number is alarmingly high and demonstrates the urgent need for verification and testing of all drinking water wells in the Indus Plain, followed by appropriate mitigation measures. PMID:28845451

  9. Polychaete richness and abundance enhanced in anthropogenically modified estuaries despite high concentrations of toxic contaminants.

    Directory of Open Access Journals (Sweden)

    Katherine A Dafforn

    Full Text Available Ecological communities are increasingly exposed to multiple chemical and physical stressors, but distinguishing anthropogenic impacts from other environmental drivers remains challenging. Rarely are multiple stressors investigated in replicated studies over large spatial scales (>1000 kms or supported with manipulations that are necessary to interpret ecological patterns. We measured the composition of sediment infaunal communities in relation to anthropogenic and natural stressors at multiple sites within seven estuaries. We observed increases in the richness and abundance of polychaete worms in heavily modified estuaries with severe metal contamination, but no changes in the diversity or abundance of other taxa. Estuaries in which toxic contaminants were elevated also showed evidence of organic enrichment. We hypothesised that the observed response of polychaetes was not a 'positive' response to toxic contamination or a reduction in biotic competition, but due to high levels of nutrients in heavily modified estuaries driving productivity in the water column and enriching the sediment over large spatial scales. We deployed defaunated field-collected sediments from the surveyed estuaries in a small scale experiment, but observed no effects of sediment characteristics (toxic or enriching. Furthermore, invertebrate recruitment instead reflected the low diversity and abundance observed during field surveys of this relatively 'pristine' estuary. This suggests that differences observed in the survey are not a direct consequence of sediment characteristics (even severe metal contamination but are related to parameters that covary with estuary modification such as enhanced productivity from nutrient inputs and the diversity of the local species pool. This has implications for the interpretation of diversity measures in large-scale monitoring studies in which the observed patterns may be strongly influenced by many factors that covary with anthropogenic

  10. Sources, pathways, and relative risks of contaminants in surface water and groundwater: a perspective prepared for the Walkerton inquiry.

    Science.gov (United States)

    Ritter, Len; Solomon, Keith; Sibley, Paul; Hall, Ken; Keen, Patricia; Mattu, Gevan; Linton, Beth

    2002-01-11

    On a global scale, pathogenic contamination of drinking water poses the most significant health risk to humans, and there have been countless numbers of disease outbreaks and poisonings throughout history resulting from exposure to untreated or poorly treated drinking water. However, significant risks to human health may also result from exposure to nonpathogenic, toxic contaminants that are often globally ubiquitous in waters from which drinking water is derived. With this latter point in mind, the objective of this commission paper is to discuss the primary sources of toxic contaminants in surface waters and groundwater, the pathways through which they move in aquatic environments, factors that affect their concentration and structure along the many transport flow paths, and the relative risks that these contaminants pose to human and environmental health. In assessing the relative risk of toxic contaminants in drinking water to humans, we have organized our discussion to follow the classical risk assessment paradigm, with emphasis placed on risk characterization. In doing so, we have focused predominantly on toxic contaminants that have had a demonstrated or potential effect on human health via exposure through drinking water. In the risk assessment process, understanding the sources and pathways for contaminants in the environment is a crucial step in addressing (and reducing) uncertainty associated with estimating the likelihood of exposure to contaminants in drinking water. More importantly, understanding the sources and pathways of contaminants strengthens our ability to quantify effects through accurate measurement and testing, or to predict the likelihood of effects based on empirical models. Understanding the sources, fate, and concentrations of chemicals in water, in conjunction with assessment of effects, not only forms the basis of risk characterization, but also provides critical information required to render decisions regarding regulatory

  11. Development of high-level radioactive waste treatment and conversion technologies 'Dry decontamination technology development for highly radioactive contaminants'

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Won Zin; Lee, K. W.; Won, H. J.; Jung, C. J.; Choi, W. K.; Kim, G. N.; Moon, J. K

    2001-04-01

    The followings were studied through the project entitled 'Dry Decontamination Technology Development for Highly Radioactive Contaminants'. 1.Contaminant Characteristics Analysis of Domestic Nuclear Fuel Cycle Projects(NFCP) and Applicability Study of the Unit Dry-Decontamination Techniques A. Classification of contaminated equipments and characteristics analysis of contaminants B. Applicability study of the unit dry-decontamination techniques 2.Performance Evaluation of Unit Dry Decontamination Technique A. PFC decontamination technique B. CO2 decontamination technique C. Plasma decontamination technique 3.Development of Residual Radiation Assessment Methodology for High Radioactive Facility Decontamination A. Development of radioactive nuclide diffusion model on highly radioactive facility structure B. Obtainment of the procedure for assessment of residual radiation dose 4.Establishment of the Design Concept of Dry Decontamination Process Equipment Applicable to Highly Radioactive Contaminants 5.TRIGA soil unit decontamination technology development A. Development of soil washing and flushing technologies B. Development of electrokinetic soil decontamination technology.

  12. Geospatial modeling of widespread arsenic contamination in unconfined, high-pH aquifers in Pakistan

    Science.gov (United States)

    Podgorski, J. E.; Eqani, S. A. M. A. S.; Heqing, S.; Berg, M.

    2016-12-01

    Arsenic-contaminated aquifers are presently estimated to affect approximately 150 million people worldwide. However, the full extent of the problem remains unknown. This is the case also in Pakistan, where previously conducted studies have focused only on individual areas of limited extent. Using a new dataset of nearly 1,200 groundwater quality samples throughout Pakistan along with existing measurements, we have created statistically based hazard and risk models of arsenic contamination in groundwater for thresholds of 10 and 50 µg/L, corresponding to the WHO and local guidelines, respectively. Logistic regression analysis was conducted using a variety of environmental indicators selected for their potential association with arsenic release and accumulation. The best logistic regression was achieved using the predictor variables of slope, Holocene geology, fluvisols, soil pH and soil organic carbon. The resultant hazard model (attached figure) shows that much of the flat, arid Indus Plain has a high probability of elevated arsenic concentrations. Other indicators that are highly correlated with elevated arsenic are aridity and proportion of land under irrigation. Unlike other known arsenic-contaminated areas of Asia, the arsenic release process in the arid Indus Plain appears to be dominated by elevated-pH dissolution, which is a consequence of alkaline topsoil and unconfined aquifers. However, pockets of reductive dissolution may also occur, primarily as a result of local groundwater contamination from municipal and agricultural sewage. Although the average pH of surface soil in the Indus Plain generally ranges between 8.0-8.5, the average pH of groundwater samples with high arsenic from this area is only 7.6. A likely scenario is that pH-induced arsenic release is occurring in the surface sediments and migrating downward into the underlying unconfined aquifer. The role of irrigation in arsenic release is unclear, although it could have a significant influence

  13. Aflatoxin Contamination of Red Chili Pepper From Bolivia and Peru, Countries with High Gallbladder Cancer Incidence Rates

    OpenAIRE

    2015-01-01

    Chilean red chili peppers contaminated with aflatoxins were reported in a previous study. If the development of gallbladder cancer (GBC) in Chile is associated with a high level of consumption of aflatoxin-contaminated red chili peppers, such peppers from other countries having a high GBC incidence rate may also be contaminated with aflatoxins. We aimed to determine whether this might be the case for red chili peppers from Bolivia and Peru. A total of 7 samples (3 from Bolivia, 4 from Peru) a...

  14. Miniaturized, High Flow, Low Dead Volume Pre-Concentrator for Trace Contaminants in Water under Microgravity Conditions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Thorleaf Research, Inc. proposes to develop a miniaturized high flow, low dead-volume pre-concentrator for monitoring trace levels of contaminants in water under...

  15. Pedagogical content knowledge and preparation of high school physics teachers

    Directory of Open Access Journals (Sweden)

    Eugenia Etkina

    2010-08-01

    Full Text Available This paper contains a scholarly description of pedagogical practices of the Rutgers Physics/Physical Science Teacher Preparation program. The program focuses on three aspects of teacher preparation: knowledge of physics, knowledge of pedagogy, and knowledge of how to teach physics (pedagogical content knowledge—PCK. The program has been in place for 7 years and has a steady production rate of an average of six teachers per year who remain in the profession. The main purpose of the paper is to provide information about a possible structure, organization, and individual elements of a program that prepares physics teachers. The philosophy of the program and the coursework can be implemented either in a physics department or in a school of education. The paper provides details about the program course work and teaching experiences and suggests ways to adapt it to other local conditions.

  16. A simple and highly effective process for the preparation of activated carbons with high surface area

    Energy Technology Data Exchange (ETDEWEB)

    Li Ying, E-mail: liyingjlu@163.com [College of Chemistry, Jilin University, Changchun 130012 (China); Ding Xuefeng; Guo Yupeng; Wang Lili; Rong Chunguang; Qu Yuning; Ma Xiaoyu [College of Chemistry, Jilin University, Changchun 130012 (China); Wang Zichen, E-mail: wangzc@jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130012 (China)

    2011-06-15

    Highlights: {yields} High surface area activated carbon can be prepared by rice husk H{sub 3}PO{sub 4} without pretreatment. {yields} The characteristics of the activated carbon were greatly influenced by post-processing method. {yields} The lower SiO{sub 2} content of the activated carbons, the higher pore volume the carbons had. {yields} Some silica in rice husk reacted with H{sub 3}PO{sub 4} to form SiP{sub 2}O{sub 7} which could be removed by post-process. - Abstract: Activated carbons with high surface area were prepared by phosphoric acid as activation agent and rice husks as precursors. It was found that the characteristics of the activated carbons were influenced not only by the preparation but also by the post-processing method. The high surface area of the activated carbons was prepared under the optimum condition (50% H{sub 3}PO{sub 4} with impregnation ratio of 5:1, activation temperature of 500 deg. C, activation time of 0.5 h, wash water temperature of 100 deg. C). SiO{sub 2} content could affect the surface area of activated carbons, either. The lower SiO{sub 2} content of the activated carbons, the higher pore volume the carbons had. The SiO{sub 2} content was 11.2% when used the optimum condition. The explanation was that silicon element in rice husks reacted with H{sub 3}PO{sub 4} to form silicon phosphate (SiP{sub 2}O{sub 7}), and it could be proved further by X-ray diffraction analysis, SiP{sub 2}O{sub 7} could be removed by post-process.

  17. High Arsenic contamination in drinking water Hand-Pumps in Khap Tola, West Champaran, Bihar, India

    Directory of Open Access Journals (Sweden)

    Siddharth eBhatia

    2014-11-01

    Full Text Available This study tests the drinking water supply of a marginalized village community of Khap Tola in the state of Bihar, a state in Northern India. Based on hand pump drinking water sample testing and analysis, we found that there was high levels of arsenic (maximum value being 397 ppb , in excess of the WHO limits of 10ppb. Analysis showed 57% of the samples from private hand-pumps in the shallow aquifer zone of 15-35m have arsenic greater than 200 ppb. Using GIS overlay analysis technique it was calculated that 25% of the residential area in the village is under high risk of arsenic contamination. Further using USEPA guidelines, it was calculated that children age group 5-10 years are under high risk of getting cancer. The Hazard Quotient calculated for 21 children taken for study, indicated that children may have adverse non-carcinogenic health impacts, in the future, with continued exposure. Since the area adds a new arsenic contaminated place in India, further geochemical analysis and health assessment needs to be done in this district of West Champaran in, Bihar.

  18. Mercury fractionation, bioavailability, and ecotoxicity in highly contaminated soils from chlor-alkali plants.

    Science.gov (United States)

    Zagury, Gerald J; Neculita, Carmen-Mihaela; Bastien, Christian; Deschênes, Louise

    2006-04-01

    Mercury (Hg) fractionation, speciation, bioavailability, and ecotoxicity were investigated in three highly contaminated soils from chlor-alkali plants. Single extractions and a validated four-step sequential extraction scheme were used. Total, volatile, and methyl-Hg concentrations were determined. Mercury was then separated in fractions defined as water-soluble (F1), exchangeable (F2), organic (F3), and residual (F4). Germination and growth inhibition of barley (Hordeum vulgare) and mortality of earthworms (Eisenia andrei) were assessed, and tissue-Hg concentrations of exposed organisms were determined. Results revealed highly (295 +/- 18-11,500 +/- 500 microg Hg/g) contaminated soils, but extracted fractions indicated relatively low mobility of Hg. Nevertheless, the water-soluble and the CaCl2-extractable fractions represented significant Hg concentrations (299 +/- 18 microg/g in soil 3, 67.4 +/- 2.3 microg/g in soil 1, and 9.5 +/- 0.3 microg/g in soil 2), and volatile Hg ranged between 14 and 98% of total Hg. Overall, Hg concentrations reached 6,560 +/- 240 microg/g in roots, 4,200 +/- 1,070 microg/g in aerial plants, and 1,410 +/- 120 microg/g in E. andrei. Earthworm mortality was 100% after exposure to the soil with the highest concentration of mobile Hg. In the latter soil, earthworm fragmentation and chlorotic plants were observed. Bioconcentration factors (BCFs) were higher in barley compared to earthworms, but BCFs yielded misleading values after exposure to the extremely contaminated soil. This study shows that Hg accumulated primarily in the roots, but results also indicate uptake of gaseous Hg by the aerial plants of barley. Tissue-Hg concentrations of both exposed organisms were correlated with water-soluble and CaCl2-extractable Hg, and growth inhibition was in agreement with Hg fractionation.

  19. Skin and surface lead contamination, hygiene programs, and work practices of bridge surface preparation and painting contractors.

    Science.gov (United States)

    Virji, M Abbas; Woskie, Susan R; Pepper, Lewis D

    2009-02-01

    A 2005 regulatory review of the lead in construction standard by the Occupational Safety and Health Administration (OSHA) noted that alternative pathways of exposure can be as significant as inhalation exposure and that noncompliance with the standard pertaining to hygiene facilities and practices was the second most commonly violated section of the standard. Noncompliance with provisions of the standard and unhealthy work and hygiene practices likely increase the likelihood of take-home lead via contaminated clothing, automobiles, and skin, thus contributing to elevated blood lead levels (BLL) among construction workers and their family members. We performed a cross-sectional study of bridge painters working for small contractors in Massachusetts to investigate causes of persistent elevated BLLs and to assess lead exposures. Thirteen work sites were evaluated for a 2-week period during which surface and skin wipe samples were collected and qualitative information was obtained on personal hygiene practices, decontamination and hand wash facilities, and respiratory protection programs. Results showed lead contamination on workers' skin, respirators, personal automobiles, and the decontamination unit, indicating a significant potential for take-home lead exposure. Overall, the geometric mean (GM) skin lead levels ranged from 373 microg on workers' faces at end of shift to 814 microg on hands at break time. The overall GM lead level inside respirators was 143 microg before work and 286 microg after work. Lead contamination was also present inside workers' personal vehicles as well as on surfaces inside the clean side of the decontamination unit. Review of the respiratory protection programs, work site decontamination and hand wash facilities, and personal hygiene practices indicated that these factors had significant impact on skin and surface contamination levels and identified significant opportunities for improving work site facilities and personal practices

  20. Perspectives of humic substances application in remediation of highly heavy metals contaminated soils in Kola Subarctic

    Science.gov (United States)

    Tregubova, Polina; Turbaevskaya, Valeria; Zakharenko, Andrey; Kadulin, Maksim; Smirnova, Irina; Stepanov, Andrey; Koptsik, Galina

    2016-04-01

    increasing of HMs mobility in the conditions of 6-weeks field experiment. Peat-humate application causes insignificant enrichment of soil by organic matter, has low influence on pH and microbiological activity. Nevertheless, in combination with lime, it raises pH and immobilizes Ni and Cu and shows best results by vegetation state. Ni and Cu mean concentrations in soil water extract of control sites are 3.7 μg kg-1 and 12.3 μg kg-1, and of sites with combination of peat-humate and lime - 0.2 μg kg-1 and 1.1 μg kg-1 respectively. Coal-humate application attended with high enrichment of soil by organic matter and it's soluble forms, changes in molecular-mass distribution, decreasing of acidity, and growth of microbe biomass (also due to using of biomates). That involves relatively HM soluble forms mobilization in variants with highest concentration of coal-humate (1%). Ni and Cu mean concentrations of those variants are 2.1 μg kg-1and 10.2 μg kg-1. Promising results obtained in short-term experiments should be supported by further investigations. Proper evaluation of humates efficiency and selection their optimal doses for remediation of contaminated soils require long-term field experiments under the influence of multicomponent contamination and diverse physical, chemical, and biological factors.

  1. Eradication of high viable loads of Listeria monocytogenes contaminating food-contact surfaces

    Directory of Open Access Journals (Sweden)

    Silvia ede Candia

    2015-07-01

    Full Text Available This study demonstrates the efficacy of cold gaseous ozone treatments at low concentrations in the eradication of high Listeria monocytogenes viable cell loads from glass, polypropylene, stainless steel and expanded polystyrene food-contact surfaces. Using a step by step approach, involving the selection of the most resistant strain-surface combinations, 11 Listeria spp. strains resulted inactivated by a continuous ozone flow at 1.07 mg m-3 after 24 or 48 h of cold incubation, depending on both strain and surface evaluated. Increasing the inoculum level to 9 log CFU coupon-1, the best inactivation rate was obtained after 48h of treatment at 3.21 mg m-3 ozone concentration when cells were deposited onto stainless steel and expanded polystyrene coupons, resulted the most resistant food-contact surfaces in the previous assays.The addition of naturally microbiologically contaminated meat extract to a high load of L. monocytogenes LMG 23775 cells, the most resistant strain out of the 11 assayed Listeria spp. strains, led to its complete inactivation after four days of treatment.To the best of our knowledge, this is the first report describing the survival of L. monocytogenes and the effect of ozone treatment under cold storage conditions on expanded polystyrene, a commonly-used material in food packaging. These results could be useful for reducing pathogen cross-contamination phenomena during cold food storage.

  2. Fabrication and characterization of thermoplastic elastomer dry adhesives with high strength and low contamination.

    Science.gov (United States)

    Bin Khaled, Walid; Sameoto, Dan

    2014-05-14

    Polydimethylsiloxane (PDMS) and polyurethane elastomers have commonly been used to manufacture mushroom shaped gecko-inspired dry adhesives with high normal adhesion strength. However, the thermosetting nature of these two materials severely limits the commercial viability of their manufacturing due to long curing times and high material costs. In this work, we introduce poly(styrene-ethylene/butylene-styrene) (SEBS) thermoplastic elastomers as an alternative for the manufacture of mushroom shaped dry adhesives with both directional and nondirectional performance. These materials are attractive for their potential to be less contaminating via oligomer transfer than thermoset elastomers, as well as being more suited to mass manufacturing. Low material transfer properties are attractive for adhesives that could potentially be used in cleanroom environments for microscale assembly and handling in which device contamination is a serious concern. We characterized a thermoplastic elastomer in terms of oligomer transfer using X-ray photoelectron spectroscopy and found that the SEBS transfers negligible amounts of its own oligomers, during contact with a gold-coated silicon surface, which may be representative of the metallic bond pads found in micro-electro-mechanical systems devices. We also demonstrate the fabrication of mushroom shaped isotropic and anisotropic adhesive fibers with two different SEBS elastomer grades using thermocompression molding and characterize the adhesives in terms of their shear-enhanced normal adhesion strength. The overall adhesion of one of the thermoplastic elastomer adhesives was found to be stronger or comparable to their polyurethane counterparts with identical dimensions.

  3. Arsenic species extraction of biological marine samples (Periwinkles, Littorina littorea) from a highly contaminated site.

    Science.gov (United States)

    Whaley-Martin, K J; Koch, I; Reimer, K J

    2012-01-15

    Arsenic is ubiquitous in the tissues of marine organisms and in uncontaminated environments it is dominantly present as the highly soluble and easily extractable non-toxic arsenical, arsenobetaine. However in contaminated environments, higher proportions of inorganic arsenic, which is much less soluble, are accumulated into the tissues of marine organisms, resulting in lower extraction efficiencies (defined as the percent extracted arsenic of the total arsenic). This study carried out a comparative analysis between three different two-step arsenic extraction methods based on Foster et al. [27] from highly contaminated tissue of the marine periwinkle, Littorina littorea. The first extraction step used 100% water, 1:1 methanol-water, or a 9:1 methanol-water as the extraction solvent and the second step consisted of a gently heated dilute nitric acid extraction. The optimized two step extraction method was 1:1 methanol-water extraction followed by a 2% HNO(3) extraction, based on maximum amounts of extracted species, including organoarsenic species.

  4. Democritos: preparing demonstrators for high power nuclear electric space propulsion

    OpenAIRE

    Masson, Frederic; Ruault, Jean-Marc; WORMS, Jean-Claude; Detsis, Emmanouil; Beaurain, André; Lassoudiere, Francois; Gaia, Enrico; Tosi, Maria -Christina; Jansen, Frank; Bauer, Waldemar; Semenkin, Alexander; Tinsley, Tim; Hodgson, Zara

    2015-01-01

    The Democritos project aims at preparing demonstrators for a megawatt class nuclearelectric space propulsion. It is funded by Horizon 2020, the R&T program of the European Community. It is a new European and Russian project, including as partners: Nuclear National Laboratory (U.K.), DLR (Germany), The Keldysh Research Center (Russia), Thales Alenia Space Italia (Italy), Snecma (France), ESF (France) and CNES (France). IEAV (Brazil) will join as an observer. Democritos is the follo...

  5. Recharge heterogeneity and high intensity rainfall events increase contamination risk for Mediterranean groundwater resources

    Science.gov (United States)

    Hartmann, Andreas; Jasechko, Scott; Gleeson, Tom; Wada, Yoshihide; Andreo, Bartolomé; Barberá, Juan Antonio; Brielmann, Heike; Charlier, Jean-Baptiste; Darling, George; Filippini, Maria; Garvelmann, Jakob; Goldscheider, Nico; Kralik, Martin; Kunstmann, Harald; Ladouche, Bernard; Lange, Jens; Mudarra, Matías; Francisco Martín, José; Rimmer, Alon; Sanchez, Damián; Stumpp, Christine; Wagener, Thorsten

    2017-04-01

    Karst develops through the dissolution of carbonate rock and results in pronounced spatiotemporal heterogeneity of hydrological processes. Karst groundwater in Europe is a major source of fresh water contributing up to half of the total drinking water supply in some countries like Austria or Slovenia. Previous work showed that karstic recharge processes enhance and alter the sensitivity of recharge to climate variability. The enhanced preferential flow from the surface to the aquifer may be followed by enhanced risk of groundwater contamination. In this study we assess the contamination risk of karst aquifers over Europe and the Mediterranean using simulated transit time distributions. Using a new type of semi-distributed model that considers the spatial heterogeneity of karst hydraulic properties, we were able to simulate karstic groundwater recharge including its heterogeneous spatiotemporal dynamics. The model is driven by gridded daily climate data from the Global Land Data Assimilation System (GLDAS). Transit time distributions are calculated using virtual tracer experiments. We evaluated our simulations by independent information on transit times derived from observed time series of water isotopes of >70 karst springs over Europe. The simulations indicate that, compared to humid, mountain and desert regions, the Mediterranean region shows a stronger risk of contamination in Europe because preferential flow processes are most pronounced given thin soil layers and the seasonal abundance of high intensity rainfall events in autumn and winter. Our modelling approach includes strong simplifications and its results cannot easily be generalized but it still highlights that the combined effects of variable climate and heterogeneous catchment properties constitute a strong risk on water quality.

  6. Diffused sunlight driven highly synergistic pathway for complete mineralization of organic contaminants using reduced graphene oxide supported photocatalyst.

    Science.gov (United States)

    Babu, Sundaram Ganesh; Ramalingam Vinoth; Neppolian, Bernaurdshaw; Dionysiou, Dionysios D; Ashokkumar, Muthupandian

    2015-06-30

    Diffused sunlight is found to be an effective light source for the efficient degradation and mineralization of organic pollutant (methyl orange as a probe) by sono-photocatalytic degradation using reduced graphene oxide (rGO) supported CuO-TiO2 photocatalyst. The prepared catalysts are characterized by XRD, XPS, UV-vis DRS, PL, photoelectrochemical, SEM-EDS and TEM. A 10 fold synergy is achieved for the first time by combining sonochemical and photocatalytic degradation under diffused sunlight. rGO loading augments the activity of bare CuO-TiO2 more than two fold. The ability of rGO in storing, transferring, and shuttling electrons at the heterojunction between TiO2 and CuO facilitates the separation of photogenerated electron-hole pairs, as evidenced by the photoluminescence results. The complete mineralization of MO and the by-products within a short span of time is confirmed by TOC analysis. Further, hydroxyl radical mediated degradation under diffused sunlight is confirmed by LC-MS. This system shows similar activity for the degradation of methylene blue and 4-chlorophenol indicating the versatility of the catalyst for the degradation of various pollutants. This investigation is likely to open new possibilities for the development of highly efficient diffused sunlight driven TiO2 based photocatalysts for the complete mineralization of organic contaminants.

  7. Superconducting Properties of MgB2 Prepared by High and Ambient Pressures

    Institute of Scientific and Technical Information of China (English)

    REN Zhi-An; CHE Guang-Can; ZHAO Zhong-Xian; CHEN Hong; DONG Cheng; NI Yong-Ming; JIA Shun-Lian; WEN Hai-Hu

    2001-01-01

    The new superconductor MgB2 has been prepared in two ways, by high pressure and ambient pressure synthesis.The superconducting properties were measured and compared. It is found that the sample prepared by highpressure is much denser than that prepared under ambient pressure. Accordingly the high pressure sample has avery narrow transition width and a much higher bulk critical current densityC

  8. High index of refraction films for dielectric mirrors prepared by metal-organic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Brusasco, R.M.

    1989-01-01

    A wide variety of metal oxides with high index of refraction can be prepared by Metal-Organic Chemical Vapor Deposition. We present some recent optical and laser damage results on oxide films prepared by MOCVD which could be used in a multilayer structure for highly reflecting (HR) dielectric mirror applications. The method of preparation affects both optical properties and laser damage threshold. 10 refs., 8 figs., 4 tabs.

  9. Corrosion Behaviour of a Highly Alloyed Austenitic Alloy UB6 in Contaminated Phosphoric Acid

    Directory of Open Access Journals (Sweden)

    M. Boudalia

    2013-01-01

    Full Text Available The influence of temperature (20–80°C on the electrochemical behaviour of passive films anodically formed on UB6 stainless steel in phosphoric acid solution (5.5 M H3PO4 has been examined by using potentiodynamic curves, electrochemical impedance spectroscopy, and Mott-Schottky analysis. UB6 stainless steel in contaminated phosphoric acid is characterised by high interfacial impedance, thereby, illustrating its high corrosion resistance. The obtained results show that the films behave as n-type and p-type semiconductors in the potential range above and below the flat band potential, respectively. This behaviour is assumed to be the consequence of the semiconducting properties of the iron oxide and chromium oxide regions which compose the passive film.

  10. Presence of a highly efficient binding to bacterial contamination can distort data from binding studies

    Energy Technology Data Exchange (ETDEWEB)

    Balcar, V.J. (Department of Anatomy, University of Sydney, N.S.W. (Australia))

    1990-12-01

    {sup 3}HGABA at low concentrations (5-10 nM) was bound by what appeared to be a GABA receptor binding site in bacterial contamination originating from a batch of distilled water. Under experimental conditions similar to those usually employed in {sup 3}HGABA binding studies, the apparent binding displayed a very high specific component and a high efficiency in terms of {sup 3}HGABA bound per mg of protein. The binding was blocked by muscimol but not by isoguvacine, SR95531 and nipecotic acid. These characteristics suggest that the presence of such spurious binding in the experiments using 3H-labeled ligands in brain homogenates may not always be very obvious and, moreover, it can result in subtle, but serious, distortions of data from such studies, which may not be immediately recognized.

  11. High levels of inorganic arsenic in rice in areas where arsenic-contaminated water is used for irrigation and cooking

    OpenAIRE

    Rahman, M. Azizur; Hasegawa, Hiroshi

    2011-01-01

    Rice is the staple food for the people of arsenic endemic South (S) and South-East (SE) Asian countries. In this region, arsenic contaminated groundwater has been used not only for drinking and cooking purposes but also for rice cultivation during dry season. Irrigation of arsenic-contaminated groundwater for rice cultivation has resulted high deposition of arsenic in topsoil and uptake in rice grain posing a serious threat to the sustainable agriculture in this region. In addition, cooking r...

  12. Highly branched dextrin prepared from high-amylose maize starch using waxy rice branching enzyme (WRBE).

    Science.gov (United States)

    Tian, Yaoqi; Chen, Huangli; Zhang, Xiwen; Zhan, Jinling; Jin, Zhengyu; Wang, Jinpeng

    2016-07-15

    Branching enzyme (BE, EC 2.4.1.18) was isolated from the developing waxy rice endosperm and used to prepare a highly branched dextrin based on high-amylose maize starch (HAMS) as a substrate. The molecular mass of the starch initially degraded quickly from 2.5 × 10(7) to 4.1 × 10(5)Da, and then stabilized, with a minimal increase during the BE treatment. The resultant branched dextrin had a narrow size distribution, with a mean molecular weight of 5.1 × 10(5)Da and a polydispersity index (PI) of 1.567. The results of high-performance anion exchange chromatography indicated that the degree of polymerization (DP) of the branched chains ranged from 3 to 27; approximately 75.26% of these chains were short (DPhighly branched dextrins with a narrow size distribution and short side chains. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Earthworm populations of highly metal-contaminated soils restored by fly ash-aided phytostabilisation.

    Science.gov (United States)

    Grumiaux, Fabien; Demuynck, Sylvain; Pernin, Céline; Leprêtre, Alain

    2015-03-01

    Highly metal contaminated soils found in the North of France are the result of intense industrial past. These soils are now unfit for the cultivation of agricultural products for human consumption. Solutions have to be found to improve the quality of these soils, and especially to reduce the availability of trace elements (TEs). Phytostabilisation and ash-aided phytostabilisation applied since 2000 to an experimental site located near a former metallurgical site (Metaleurop-Nord) was shown previously as efficacious in reducing TEs mobility in soils. The aim of the study was to check whether this ten years trial had influenced earthworm communities. This experimental site was compared to plots located in the surroundings and differing by the use of soils. Main results are that: (1) whatever the use of soils, earthworm communities are composed of few species with moderate abundance in comparison with communities found in similar habitats outside the TEs-contaminated area, (2) the highest abundance and specific richness (4-5 species) were observed in afforested plots with various tree species, (3) ash amendments in afforested plots did not increase the species richness and modified the communities favoring anecic worms but disfavoring epigeic ones. These findings raised the questions of when and how to perform the addition of ashes firstly, to avoid negative effects on soil fauna and secondly, to keep positive effects on metal immobilization.

  14. Assessment of the degree of contamination of rat germ cell preparations using specific cDNA probes

    Directory of Open Access Journals (Sweden)

    Savaris R.F.

    1997-01-01

    Full Text Available Recent reports showing a decrease in sperm count in men have brought new concerns about male infertility. Animal models have been widely used to provide some relevant information about the human male gamete, and extrapolations are made to men and to the clinical context. The present study assesses one of the methods used for separation of germ cells of the adult rat testis, namely centrifugal elutriation followed by density gradients (Percoll®. This method was chosen since it presents the best results for cell purity in separating germ cells from the rat testis. A comparison between continuous and discontinuous Percoll® gradients was performed in order to identify the best type of gradient to separate the cells. Maximal cell purity was obtained for spermatocytes (81 ± 8.2%, mean ± SEM and spermatids (84 ± 2.6% using centrifugal elutriation followed by continuous Percoll® gradients. A significant difference in purity was observed between elongating spermatids harvested from continuous Percoll® gradients and from discontinuous gradients. Molecular analysis was used to assess cell contamination by employing specific probes, namely transition protein 2 (TP2, mitochondrial cytochrome C oxidase II (COX II, and sulfated glycoprotein 1 (SGP1. Molecular analysis of the samples demonstrated that morphological criteria are efficient in characterizing the main composition of the cell suspension, but are not reliable for identifying minimal contamination from other cells. Reliable cell purity data should be established using molecular analysis

  15. Effect of contaminations and surface preparation on the work function of single layer MoS2.

    Science.gov (United States)

    Ochedowski, Oliver; Marinov, Kolyo; Scheuschner, Nils; Poloczek, Artur; Bussmann, Benedict Kleine; Maultzsch, Janina; Schleberger, Marika

    2014-01-01

    Thinning out MoS2 crystals to atomically thin layers results in the transition from an indirect to a direct bandgap material. This makes single layer MoS2 an exciting new material for electronic devices. In MoS2 devices it has been observed that the choice of materials, in particular for contact and gate, is crucial for their performance. This makes it very important to study the interaction between ultrathin MoS2 layers and materials employed in electronic devices in order to optimize their performance. In this work we used NC-AFM in combination with quantitative KPFM to study the influence of the substrate material and the processing on single layer MoS2 during device fabrication. We find a strong influence of contaminations caused by the processing on the surface potential of MoS2. It is shown that the charge transfer from the substrate is able to change the work function of MoS2 by about 40 meV. Our findings suggest two things. First, the necessity to properly clean devices after processing as contaminations have a great impact on the surface potential. Second, that by choosing appropriate materials the work function can be modified to reduce contact resistance.

  16. Coliform contamination of vegetables obtained from popular restaurants in Guadalajara, Mexico, and Houston, Texas.

    Science.gov (United States)

    Koo, Hoonmo L; Jiang, Zhi-Dong; Brown, Eric; Garcia, Coralith; Qi, Huibin; Dupont, Herbert L

    2008-07-15

    Food is the primary vehicle of transmission for traveler's diarrhea. We evaluated coliform contamination of vegetables from popular restaurants in Guadalajara, Mexico, and Houston, Texas. Contamination of vegetables in Guadalajara restaurants was widespread. Prevention of traveler's diarrhea by avoidance of "high-risk" foods may be unsuccessful, because contamination of foods may occur regardless of how they are prepared.

  17. Assessment of Potential Location of High Arsenic Contamination Using Fuzzy Overlay and Spatial Anisotropy Approach in Iron Mine Surrounding Area

    Directory of Open Access Journals (Sweden)

    Thanes Weerasiri

    2014-01-01

    Full Text Available Fuzzy overlay approach on three raster maps including land slope, soil type, and distance to stream can be used to identify the most potential locations of high arsenic contamination in soils. Verification of high arsenic contamination was made by collection samples and analysis of arsenic content and interpolation surface by spatial anisotropic method. A total of 51 soil samples were collected at the potential contaminated location clarified by fuzzy overlay approach. At each location, soil samples were taken at the depth of 0.00-1.00 m from the surface ground level. Interpolation surface of the analysed arsenic content using spatial anisotropic would verify the potential arsenic contamination location obtained from fuzzy overlay outputs. Both outputs of the spatial surface anisotropic and the fuzzy overlay mapping were significantly spatially conformed. Three contaminated areas with arsenic concentrations of 7.19±2.86, 6.60±3.04, and 4.90±2.67 mg/kg exceeded the arsenic content of 3.9 mg/kg, the maximum concentration level (MCL for agricultural soils as designated by Office of National Environment Board of Thailand. It is concluded that fuzzy overlay mapping could be employed for identification of potential contamination area with the verification by surface anisotropic approach including intensive sampling and analysis of the substances of interest.

  18. Assessment of potential location of high arsenic contamination using fuzzy overlay and spatial anisotropy approach in iron mine surrounding area.

    Science.gov (United States)

    Weerasiri, Thanes; Wirojanagud, Wanpen; Srisatit, Thares

    2014-01-01

    Fuzzy overlay approach on three raster maps including land slope, soil type, and distance to stream can be used to identify the most potential locations of high arsenic contamination in soils. Verification of high arsenic contamination was made by collection samples and analysis of arsenic content and interpolation surface by spatial anisotropic method. A total of 51 soil samples were collected at the potential contaminated location clarified by fuzzy overlay approach. At each location, soil samples were taken at the depth of 0.00-1.00 m from the surface ground level. Interpolation surface of the analysed arsenic content using spatial anisotropic would verify the potential arsenic contamination location obtained from fuzzy overlay outputs. Both outputs of the spatial surface anisotropic and the fuzzy overlay mapping were significantly spatially conformed. Three contaminated areas with arsenic concentrations of 7.19 ± 2.86, 6.60 ± 3.04, and 4.90 ± 2.67 mg/kg exceeded the arsenic content of 3.9 mg/kg, the maximum concentration level (MCL) for agricultural soils as designated by Office of National Environment Board of Thailand. It is concluded that fuzzy overlay mapping could be employed for identification of potential contamination area with the verification by surface anisotropic approach including intensive sampling and analysis of the substances of interest.

  19. Potassium vapor assisted preparation of highly graphitized hierarchical porous carbon for high rate performance supercapacitors

    Science.gov (United States)

    Liu, Zheng; Zeng, Ying; Tang, Qunli; Hu, Aiping; Xiao, Kuikui; Zhang, Shiying; Deng, Weina; Fan, Binbin; Zhu, Yanfei; Chen, Xiaohua

    2017-09-01

    Ultrahigh graphitized carbon microspheres with rich hierarchical pores (AGHPCM-1) have been successfully synthesized through the one-step activation-carbonization strategy (OACS) with porous sulfonated poly-divinylbenzene as the carbon precursor, iron as the hard template and catalyst, and potassium hydroxide (KOH) as activation agent. Through the XRD, TEM, Raman and BET analysis, AGHPCM-1 shows very high graphitization degree and rich micro-, meso- and macro-pores. More importantly, the mechanism for KOH to improve the graphitization degree of carbon materials in OACS has been illustrated by the thermodynamical theory. The tremendous heat releasing from the reaction between the catalyst precursor of Fe2O3 and potassium vapor plays a key role in the formation of graphitized carbon. It may provide a general direction to prepare highly graphitized porous carbon at a moderate temperature. Integrating the advantages of high graphitization degree and rich hierarchical porous structure, the AGHPCM-1 exhibits an excellent rate performance with a response to up to the high current density of 150 A g-1 and high scan rate of 2000 mV s-1. No obvious capacitance decay can be observed after 10000 charge/discharge cycles even at the high current density of 20 A g-1.

  20. Preparation and Characterization of Highly Spherical Silica-titania Aerogel Beads with High Surface Area

    Directory of Open Access Journals (Sweden)

    YU Yu-xi

    2017-02-01

    Full Text Available The silica-titania aerogel beads were synthesized through sol-gel reaction followed by supercritical drying, in which TEOS and TBT as co-precursors, EtOH as solvents, HAC and NH3·H2O as catalysts. The as-prepared aerogel beads were characterized by SEM,TEM,XRD,FT-IR,TG-DTA and nitrogen adsorption-desorption. The results indicate that the diameter distribution of beads are between 1-8mm, the average diameter of beads is 3.5mm. The aerogel beads have nanoporous network structure with high specific surface area of 914.5m2/g, and the TiO2 particles are distributed in the aerogel uniformly, which keep the anatase crystal under high temperature.

  1. Measurement of metallic contaminants in food with a high-T{sub c} SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Saburo; Natsume, Miyuki; Uchida, Masashi; Hotta, Naoki; Matsuda, Takemasa; Spanut, Zarina A; Hatsukade, Yoshimi [Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi Aichi 441-8580 (Japan)

    2004-04-01

    We have proposed and demonstrated a high-T{sub c} SQUID system for detecting metallic contaminants in foodstuffs. There is a demand for the development of systems for detecting not only magnetic materials but also non-magnetic materials such as Cu and aluminium in foodstuffs to ensure food safety. The system consists of a SQUID magnetometer, an excitation coil and a permanent magnet. For a non-magnetic sample, an AC magnetic field is applied during detection to induce an eddy current in the sample. For a magnetizable sample, a strong magnetic field is applied to the sample prior to the detection attempt. We were able to detect a stainless steel ball with a diameter of 0.1 mm and a Cu ball less than 1 mm in diameter, for example.

  2. Plutonium Decontamination Using CBI Decon Gel 1101 in Highly Contaminated and Unique Areas at LLNL

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, M; Fischer, R P; Thoet, M M; O' Neill, M; Edgington, G

    2008-06-09

    A highly contaminated glove-box at LLNL containing plutonium was decontaminated using a strippable decontamination gel. 6 x 12 inch quadrants were mapped out on each of the surfaces. The gel was applied to various surfaces inside the glove-box and was allowed to cure. The radioactivity in each quadrant was measured using a LLNL Blue Alpha meter with a 1.5 inch standoff distance. The results showed decontamination factors of 130 and 210 on cast steel and Lexan{reg_sign} surfaces respectively after several applications. The gel also absorbed more than 91% of the radiation emitted from the surfaces during gel curing. The removed strippable film was analyzed by neutron multiplicity counting and gamma spectroscopy, yielding relative mass information and radioisotopic composition respectively.

  3. REMEDIATION OF SOILS CONTAMINATED WITH MOTOR OIL BY HIGHLY BIODEGRADABLE SURFACTANTS

    Directory of Open Access Journals (Sweden)

    Ignacio Moya-Ramírez

    2014-06-01

    Full Text Available The remediation of a sandy soil contaminated with motor oil was studied by applying two different washing procedures: one discontinuous and the other continuous. In addition the capacity of three highly biodegradable surfactants, two synthetic (Glucopon 600 and Findet 1214N/23 and a biosurfactant from Bacillus subtilis, to enhance oil removal was tested. The results obtained with the continuous procedure were much better than those achieved with the discontinuous one, even in experiments conducted with distilled water. Both the addition of surfactants and the rise in temperature significantly increased the removal of the pollutant in experiments conducted with the discontinuous procedure, but the biosurfactant showed a higher capacity for soil remediation than the synthetic surfactants at concentrations close to its CMC. Conversely, when the continuous method was used, surfactant concentration seems to have a lower effect on motor oil removal, at least below the CMC.

  4. Preparation and characterization of a biochar from pistachio hull biomass and its catalytic potential for ozonation of water recalcitrant contaminants.

    Science.gov (United States)

    Moussavi, Gholamreza; Khosravi, Rasoul

    2012-09-01

    This work introduces a biochar as novel catalyst prepared from the pistachio hull, and demonstrates its catalytic potential for degrading the reactive red 198 (RR198) dye in catalytic ozonation processes (COPs). The prepared pistachio hull biochar (PHB) was a macroporous, basic material with low specific surface area. PHB had the greatest catalytic potential at an optimal alkaline pH of 10. Significant catalytic potential was observed when PHB was added to the ozonation reactor; a 58.4% catalytic potential was obtained in the decolorization of RR198 in the COP with 0.2g of catalyst after a reaction time of 60 min. A 71% mineralization (TOC reduction) of the dye solution was observed in the COP after a reaction time of 60 min. Overall, it can be concluded from the experimental results that the PHB is a promising and affordable catalyst for use in COPs for treatment of resistant organic compounds.

  5. The risk of river pollution due to washout from contaminated floodplain water bodies during periods of high magnitude floods

    Science.gov (United States)

    Lyubimova, T.; Lepikhin, A.; Parshakova, Ya.; Tiunov, A.

    2016-03-01

    The risk of river pollution due to washout (removal of pollutants) from contaminated floodplain water bodies (floodplain lakes and quarries whose origin is related to the large-scale mining of nonmetallic building materials in the floodplain zone) during high magnitude flood periods is analyzed using a combination of one-, two- and three-dimensional hydrodynamic modeling and in situ measurements. The modeling performed for the floodplain water bodies contaminated by N compounds shows that during large magnitude floods washout occurs. The washout process consists of two stages: an initial rapid stage lasting about two hours during which the upper (3-4 m thick) layer is washed out, followed by a second stage when the concentration of NH4-N in the floodplain water body remains nearly constant. The maximum contaminant concentration in the river in the vicinity of a water intake for drinking water located 21 km downstream is attained about 9 h from the beginning of the flood; concentration of NH4-N can reach values several times larger than acceptable concentration guidelines. The initial primary peak in contaminant concentration at the water intake is followed by a slight decrease in contaminant concentration; a second peak related to the contaminant transport through the inundated floodplain subsequently occurs, after which the concentration slowly decreases, reaching acceptable values after 30-40 h. Contaminated floodplain water bodies located near drinking water supply systems are not significant sources of contamination during small and moderate floods, but during high magnitude floods, they can become sources of water pollution. Operational measures that can decrease potential health risks are discussed.

  6. Preparation of Zirconia-Ceria Powders with High Specific Surface Area

    Institute of Scientific and Technical Information of China (English)

    Wang Enguo; Mei Fang

    2004-01-01

    Zirconia-ceria mixed oxide powders were prepared by high temperature aging method.The effects of the temperature and the time of aging, cerium content and calcination on powder performance were studied.The result shows that high temperature aging is an efficient way of preparation of ZrO2-CeO2 mixed oxide powders with high specific surface area and good thermal stability, and that addition of a small amount of cerium to hydrous zirconia can promote the preparation of high specific surface area powders.

  7. Daily disinfection of high-touch surfaces in isolation rooms to reduce contamination of healthcare workers' hands.

    Science.gov (United States)

    Kundrapu, Sirisha; Sunkesula, Venkata; Jury, Lucy A; Sitzlar, Brett M; Donskey, Curtis J

    2012-10-01

    In a randomized nonblinded trial, we demonstrated that daily disinfection of high-touch surfaces in rooms of patients with Clostridium difficile infection and methicillin-resistant Staphylococcus aureus colonization reduced acquisition of the pathogens on hands after contacting high-touch surfaces and reduced contamination of hands of healthcare workers caring for the patients.

  8. A cleaner two-step synthesis of high purity diallyldimethylammonium chloride monomers for flocculant preparation

    Institute of Scientific and Technical Information of China (English)

    TIAN Bing-hui; FAN Bin; PENG Xian-jia; LUAN Zhao-kun

    2005-01-01

    In order to improve the flocculation efficiency of polydiallyldimethylammonium chloride (PDADMAC), high molecular weight PDADMAC should be prepared from high purity diallyldimethylammonium chloride(DADMAC) monomers. In this paper, a cleaner method with microwave irradiation and alkali solidification was proposed for preparing high pure DADMAC by selective heating under low temperature, and the prepared high purity DADMAC is characterized using FTIR and atomic absorption spectrometry. The new method provides a solution to the key technical problem of PDADMAC synthesis. Comparing with the conventional methods, the results showed that the advantages of the novel synthesis include: (a) high purity DADMAC is improved from 57% to 71%; (b) reaction time of tertiary amine preparation is shortened from 6 h to 7 min; (c) water instead of acetone was used as reaction medium; (d) toxic by-products,wastewater and waste gas are eliminated. Flocculant made from the synthesized high purity DADMAC monomers was proved more efficient in flocculation tests.

  9. Preparation of highly preferred orientation TiB2 coatings

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper focuses on the preparation of titanium diboride (TiB2) coatings on the graphite substrate by continuous current plating (CCP) and pulse current plating (PIC) electrochemical techniques in fluoride electrolytes (LiF-NaF-KF)containing K2TiF6 and KBF4 as the electrochemically-active components at 700℃. Thick leveled and uniform coatings were obtained and were composed of relatively pure TiB2. The effect of the experimental parameters on the microstructure of the coatings was studied. The results showed the electrodeposition with PIC produced coatings with better quality, when compared with those obtained by CCP, under the conditions of the current density i = 0.6 A/cm2, frequency = 100 Hz, and ton/toff = 4/1. XRD analysis indicated that the preferred orientation of coatings is (110) plane, which is in accordance with the prediction of the two-dimensional crystal nuclei theory. The effect of a ratio of ton/toff and frequency on the crystal size, texture coefficient and microstress was also investigated.

  10. Preparation of Ultra-High-Speed Casein Trade Mark Adhesive

    Institute of Scientific and Technical Information of China (English)

    Xiong-Zhi Wu; Yu-Jiao Li

    2005-01-01

    @@ 1Introduction In present trade mark adhesives for beer bottle labeling are mostly prepared based on starch[1] ,polyvinyl formal[2] and their derivants[3-5] ,but they can only be applied to the labeling speed of 20 000 bottle/h and their water proofness are not satisfactory, especially when the water temperature is 0℃ below. The application of metal foil requires that sealing and labeling must be finished at the same time, but different penetrating speed of water in metal foil and paper label causes different drying speed, and also, the labeling speed and need of iced beer are increasing now, so these changes result in more strict requirements for adhesive.In this paper the chelating casein adhesive was obtained with casein as main moldings, urea as dispersing agent, starch as auxiliary, and ZnSO4 as cross-linked agent. The effects of dispersing agent, cross-linked agent and starch on the performances of adhesive were investigated.

  11. Extractive process for preparing high purity magnesium chloride hexahydrate

    Directory of Open Access Journals (Sweden)

    Fezei Radouanne

    2012-01-01

    Full Text Available This paper refers a method for the preparation of magnesium chloride hexahydrate (bischofite from Sebkha el Melah of Zarzis Tunisian natural brine. It is a five-stage process essentially based on crystallization by isothermal evaporation and chemical precipitation. The two first steps were dedicated to the crystallization of sodium chloride and potassiummagnesium double salts, respectively. Then, the resulting liquor was desulfated using calcium chloride solution. After that another isothermal evaporation stage was implemented in order to eliminate potassium ions in the form of carnallite, KCl.MgCl2.6H2O. At the end of this step, the recovered solution primarily composed of magnesium and chloride ions was treated by dioxan in order to precipitate magnesium chloride as MgCl2.6H2O.C4H8O2. This compound dried at constant temperature of 100°C gave good quality magnesium chloride hexahydrate. Besides this salt, the various by-products obtained from the different treatment stages are also useful.

  12. Preparation of electrochemically active silicon nanotubes in highly ordered arrays

    Directory of Open Access Journals (Sweden)

    Tobias Grünzel

    2013-10-01

    Full Text Available Silicon as the negative electrode material of lithium ion batteries has a very large capacity, the exploitation of which is impeded by the volume changes taking place upon electrochemical cycling. A Si electrode displaying a controlled porosity could circumvent the difficulty. In this perspective, we present a preparative method that yields ordered arrays of electrochemically competent silicon nanotubes. The method is based on the atomic layer deposition of silicon dioxide onto the pore walls of an anodic alumina template, followed by a thermal reduction with lithium vapor. This thermal reduction is quantitative, homogeneous over macroscopic samples, and it yields amorphous silicon and lithium oxide, at the exclusion of any lithium silicides. The reaction is characterized by spectroscopic ellipsometry for thin silica films, and by nuclear magnetic resonance and X-ray photoelectron spectroscopy for nanoporous samples. After removal of the lithium oxide byproduct, the silicon nanotubes can be contacted electrically. In a lithium ion electrolyte, they then display the electrochemical waves also observed for other bulk or nanostructured silicon systems. The method established here paves the way for systematic investigations of how the electrochemical properties (capacity, charge/discharge rates, cyclability of nanoporous silicon negative lithium ion battery electrode materials depend on the geometry.

  13. Innovative Noyce Program for Preparing High School Physics Teachers.

    Science.gov (United States)

    Hagedorn, Eric; Kosheleva, Olga; Wagler, Amy; Wagler, Ron

    2011-10-01

    The ``Robert Noyce Scholarships for Teaching Miners'' program at the University of Texas at El Paso currently consists of 14 mathematics majors minoring in secondary education, most of whom are preparing for the Mathematics-Physics Certification. From the time of their selection (junior year), till after they begin teaching, participants in this program will have financial support consisting of a 10,000 per year scholarship during the last two years in college. Programmatic support during these two years consists of four, half-day workshops emphasizing: 1) inquiry-based teaching, 2) mathematics & science integration, and 3) actual inquiry in the form of a senior research project. The workshops are facilitated by a team of university faculty and school district partners (EPISD and YISD). These district partners help with the workshops, but also mentor the scholars when placed at their classroom observation and student teacher sites. Once the scholars graduate and receive certification, they will experience unique induction year support: being hired in pairs or small groups and placed together in the same school. This placement with classmates combined with the mentoring of the same district personnel with whom they are familiar is hypothesized to be uniquely effective.

  14. High Tolerance to Iron Contamination in Lead Halide Perovskite Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Poindexter, Jeremy R. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Hoye, Robert L. Z. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Nienhaus, Lea [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Kurchin, Rachel C. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Morishige, Ashley E. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Looney, Erin E. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Osherov, Anna [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Correa-Baena, Juan-Pablo [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Lai, Barry [Advanced; Bulović, Vladimir [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Stevanović, Vladan [Colorado School of Mines, 1500; National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States; Bawendi, Moungi G. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Buonassisi, Tonio [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States

    2017-07-05

    The relationship between charge-carrier lifetime and the tolerance of lead halide perovskite (LHP) solar cells to intrinsic point defects has drawn much attention by helping to explain rapid improvements in device efficiencies. However, little is known about how charge-carrier lifetime and solar cell performance in LHPs are affected by extrinsic defects (i.e., impurities), including those that are common in manufacturing environments and known to introduce deep levels in other semiconductors. Here, we evaluate the tolerance of LHP solar cells to iron introduced via intentional contamination of the feedstock and examine the root causes of the resulting efficiency losses. We find that comparable efficiency losses occur in LHPs at feedstock iron concentrations approximately 100 times higher than those in p-type silicon devices. Photoluminescence measurements correlate iron concentration with nonradiative recombination, which we attribute to the presence of deep-level iron interstitials, as calculated from first-principles, as well as iron-rich particles detected by synchrotron-based X-ray fluorescence microscopy. At moderate contamination levels, we witness prominent recovery of device efficiencies to near-baseline values after biasing at 1.4 V for 60 s in the dark. We theorize that this temporary effect arises from improved charge-carrier collection enhanced by electric fields strengthened from ion migration toward interfaces. Our results demonstrate that extrinsic defect tolerance contributes to high efficiencies in LHP solar cells, which inspires further investigation into potential large-scale manufacturing cost savings as well as the degree of overlap between intrinsic and extrinsic defect tolerance in LHPs and 'perovskite-inspired' lead-free stable alternatives.

  15. Heat and hazardous contaminant transports in ventilated high-rise industrial halls

    Institute of Scientific and Technical Information of China (English)

    王沨枫; 刘志强; Christoph van Treeck; 王汉青; 唐文武; 寇广孝

    2015-01-01

    Performances and efficiencies of displacement ventilation (DV) and partial ventilation (PV) for industrial halls of different configurations as well as the heat and mass transports within the industrial halls were numerically investigated. Three levels of Rayleigh number(5.8´1010, 1.0´1012 and 2.1´1012) and two values of source contaminant flux (5 mg/s and 50 mg/s) were considered. The inlet Reynolds numbers were 2´104, 5´104, 1.5´105 and 4.5´105 for DV and 5´105, 1´106, 2´106 and 4´106 for PV, respectively. From the results, it is concluded that the above parameters have very complex impacts on the conjugated heat and mass transports. From points of view of acceptable indoor air quality and ventilation efficiency, PV atRe=1´106with side-located sources and 65% of the supply air extracted through floor level outlets is the best choice whenRa=5.8´1010. However, DVs atRe=5´104andRe=1.5´105 with center-located sources and floor-mounted air suppliers are the best choices forRa=1.0´1012 andRa=2.1´1012, respectively. When source contaminant flux reaches 50 mg/s, local extraction as a supplement of general ventilation is recommended. The results can be a first approximation to 3D numerical investigation and preliminary ventilation system design guidelines for high-rise industrial halls.

  16. Higher Education Faculty versus High School Teacher: Does Pedagogical Preparation Make a Difference?

    Science.gov (United States)

    Jensen, Jamie L.

    2011-01-01

    Higher education faculty are not held to the same standard of pedagogical preparation as primary and secondary teachers. This perspectives essay points out the difference in pedagogical preparations between higher education faculty and high school teachers. The essay highlights research indicating the importance of pedagogical training, offers…

  17. Bioremediation of weathered petroleum hydrocarbon soil contamination in the Canadian High Arctic: laboratory and field studies.

    Science.gov (United States)

    Sanscartier, David; Laing, Tamsin; Reimer, Ken; Zeeb, Barbara

    2009-11-01

    The bioremediation of weathered medium- to high-molecular weight petroleum hydrocarbons (HCs) in the High Arctic was investigated. The polar desert climate, contaminant characteristics, and logistical constraints can make bioremediation of persistent HCs in the High Arctic challenging. Landfarming (0.3 m(3) plots) was tested in the field for three consecutive years with plots receiving very little maintenance. Application of surfactant and fertilizers, and passive warming using a greenhouse were investigated. The field study was complemented by a laboratory experiment to better understand HC removal mechanisms and limiting factors affecting bioremediation on site. Significant reduction of total petroleum HCs (TPH) was observed in both experiments. Preferential removal of compounds nC16 occurred, whereas in the field, TPH reduction was mainly limited to removal of compounds nC16 was observed in the fertilized field plots only. The greenhouse increased average soil temperatures and extended the treatment season but did not enhance bioremediation. Findings suggest that temperature and low moisture content affected biodegradation of HCs in the field. Little volatilization was measured in the laboratory, but this process may have been predominant in the field. Low-maintenance landfarming may be best suited for remediation of HCs compounds

  18. On-line coupled high performance liquid chromatography-gas chromatography for the analysis of contamination by mineral oil. Part 1: method of analysis.

    Science.gov (United States)

    Biedermann, Maurus; Grob, Koni

    2012-09-14

    For the analysis of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH), on-line coupled high performance liquid chromatography-gas chromatography-flame ionization detection (HPLC-GC-FID) offers important advantages: it separates MOSH and MOAH in robust manner, enables direct injection of large aliquots of raw extracts (resulting in a low detection limit), avoids contamination of the sample during preparation and is fully automated. This review starts with an overview of the technology, particularly the fundamentals of introducing large volumes of solvent into GC, and their implementation into various transfer techniques. The main part deals with the concepts of MOSH and MOAH analysis, with a thorough discussion of the choices made. It is followed by a description of the method. Finally auxiliary tools are summarized to remove interfering components, enrich the sample in case of a high fat content and obtain additional information about the MOSH and MOAH composition.

  19. Preparation of cold molecules for high-precision measurements

    Science.gov (United States)

    Wall, T. E.

    2016-12-01

    Molecules can be used to test fundamental physics. Such tests often require cold molecules for detailed spectroscopic analysis. Cooling internal degrees of freedom provides a high level of state-selectivity, with large populations in the molecular states of interest. Cold translational motion allows slow, bright beams to be created, allowing long interaction times. In this tutorial article we describe the common techniques for producing cold molecules for high-precision spectroscopy experiments. For each technique we give examples of its application in experiments that use molecular structure to probe fundamental physics, choosing one experiment in particular as a case study. We then discuss a number of new techniques, some currently under development, others proposed, that promise high flux sources of cold molecules applicable to precise spectroscopic tests of fundamental physics.

  20. Thermal Conductivity of Foam Glasses Prepared using High Pressure Sintering

    DEFF Research Database (Denmark)

    Østergaard, Martin Bonderup; Petersen, Rasmus Rosenlund; König, Jakob

    with open or closed pores. If only open pores exist, air is the dominating medium for the insulating effect. However, closed pores make it possible to trap gases inside the foam. The gas can be introduced either chemically, through foaming agents, or physically, by gas compression-decompression at high...... using helium, nitrogen, or argon. The sintering result in closed-porous body with high pressure bubbles. Subsequent reheating above the glass transition temperature resulted in an expansion of the bubbles. The entrapped gas composition was analysed by gas chromatography. Furthermore, we investigated how...

  1. High sensitivity detection and characterization of the chemical state of trace element contamination on silicon wafers

    CERN Document Server

    Pianetta, Piero A; Baur, K; Brennan, S; Homma, T; Kubo, N

    2003-01-01

    Increasing the speed and complexity of semiconductor integrated circuits requires advanced processes that put extreme constraints on the level of metal contamination allowed on the surfaces of silicon wafers. Such contamination degrades the performance of the ultrathin SiO sub 2 gate dielectrics that form the heart of the individual transistors. Ultimately, reliability and yield are reduced to levels that must be improved before new processes can be put into production. It should be noted that much of this metal contamination occurs during the wet chemical etching and rinsing steps required for the manufacture of integrated circuits and industry is actively developing new processes that have already brought the metal contamination to levels beyond the measurement capabilities of conventional analytical techniques. The measurement of these extremely low contamination levels has required the use of synchrotron radiation total reflection X-ray fluorescence (SR-TXRF) where sensitivities 100 times better than conv...

  2. High-level expression, purification, polyclonal antibody preparation ...

    African Journals Online (AJOL)

    user

    2011-02-14

    Feb 14, 2011 ... Full Length Research Paper. High-level expression ... resistance severely compromises effective therapeutic options. ... In the present study, we first report the expression of the oprD ... databases of National Center for Biotechnology Information (NCBI) ..... assembly of the head of bacteriophage T4. Nature.

  3. Preparation, characterization and biocompatibility studies on risperidone-loaded solid lipid nanoparticles (SLN): high pressure homogenization versus ultrasound.

    Science.gov (United States)

    Silva, A C; González-Mira, E; García, M L; Egea, M A; Fonseca, J; Silva, R; Santos, D; Souto, E B; Ferreira, D

    2011-08-01

    The suitability of solid lipid nanoparticles (SLN) for the encapsulation of risperidone (RISP), an antipsychotic lipophilic drug, was assessed for oral administration. The hot high pressure homogenization (HPH) and the ultrasound (US) technique were used as production methods for SLN. All the studies on the SLN formulations were done in parallel, in order to compare the results and conclude about the advantages and limitations of both techniques. The particle sizes were in the nanometer range for all prepared SLN formulations and the zeta potential absolute values were high, predicting good long-term stability. Optical analyses demonstrated the achievement of stable colloidal dispersions. Physicochemical characterization of dispersions and bulk lipids, performed by differential scanning calorimetry (DSC) and X-ray assays, support prediction of occurrence of drug incorporation in the SLN and good long term stability of the systems. The toxicity of SLN with Caco-2 cells and the existence of contaminations derived from the production equipments were assessed by the (4,5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide (MTT) assay. The results showed 90% of cell viability after SLN exposure, with no significant differences within all prepared formulations (p > 0.05). From this study, we conclude that SLN can be considered as efficient carriers for RISP encapsulation. Moreover, HPH and US revealed to be both effective methods for SLN production.

  4. High resolution modeling of agricultural nitrogen to identify private wells susceptible to nitrate contamination.

    Science.gov (United States)

    Hoppe, Brendalynn; White, Denis; Harding, Anna; Mueller-Warrant, George; Hope, Bruce; Main, Eric

    2014-12-01

    Given the lack of data on private wells, public health and water quality specialists must explore alternative datasets for understanding associated exposures and health risks. Characterizing agricultural nitrogen inputs would be valuable for identifying areas where well water safety may be compromised. This study incorporated existing methods for estimating nutrient loading at the county level with datasets derived from a state permitting program for confined animal feeding operations and agricultural enterprise budget worksheets to produce a high resolution agricultural nitrogen raster map. This map was combined with data on soil leachability and new well locations. An algorithm was developed to calculate nitrogen loading and leachability within 1,000 meters of each well. Wells with a nonzero nitrogen total linked to soils with high leachability were categorized and displayed on maps communicating well susceptibility across the state of Oregon. Results suggest that 4% of recently drilled wells may be susceptible to nitrate contamination, while areas identified for mitigation are too restrictive to include all susceptible wells. Predicted increases in population density and the steady addition of approximately 3,800 new wells annually may lead to a large number of residents, especially those in rural areas, experiencing long-term exposures to nitrate in drinking water.

  5. Pyrosequencing of antibiotic-contaminated river sediments reveals high levels of resistance and gene transfer elements.

    Directory of Open Access Journals (Sweden)

    Erik Kristiansson

    Full Text Available The high and sometimes inappropriate use of antibiotics has accelerated the development of antibiotic resistance, creating a major challenge for the sustainable treatment of infections world-wide. Bacterial communities often respond to antibiotic selection pressure by acquiring resistance genes, i.e. mobile genetic elements that can be shared horizontally between species. Environmental microbial communities maintain diverse collections of resistance genes, which can be mobilized into pathogenic bacteria. Recently, exceptional environmental releases of antibiotics have been documented, but the effects on the promotion of resistance genes and the potential for horizontal gene transfer have yet received limited attention. In this study, we have used culture-independent shotgun metagenomics to investigate microbial communities in river sediments exposed to waste water from the production of antibiotics in India. Our analysis identified very high levels of several classes of resistance genes as well as elements for horizontal gene transfer, including integrons, transposons and plasmids. In addition, two abundant previously uncharacterized resistance plasmids were identified. The results suggest that antibiotic contamination plays a role in the promotion of resistance genes and their mobilization from environmental microbes to other species and eventually to human pathogens. The entire life-cycle of antibiotic substances, both before, under and after usage, should therefore be considered to fully evaluate their role in the promotion of resistance.

  6. Antimicrobial activity of filamentous fungi isolated from highly antibiotic-contaminated river sediment

    Directory of Open Access Journals (Sweden)

    K. Stefan Svahn

    2012-05-01

    Full Text Available Background: Filamentous fungi are well known for their production of substances with antimicrobial activities, several of which have formed the basis for the development of new clinically important antimicrobial agents. Recently, environments polluted with extraordinarily high levels of antibiotics have been documented, leading to strong selection pressure on local sentinel bacterial communities. In such microbial ecosystems, where multidrug-resistant bacteria are likely to thrive, it is possible that certain fungal antibiotics have become less efficient, thus encouraging alternative strategies for fungi to compete with bacteria. Methods: In this study, sediment of a highly antibiotic-contaminated Indian river was sampled in order to investigate the presence of cultivable filamentous fungi and their ability to produce substances with antimicrobial activity. Results: Sixty one strains of filamentous fungi, predominantly various Aspergillus spp. were identified. The majority of the Aspergillus strains displayed antimicrobial activity against methicillin-resistant Staphylococcus aureus, extended-spectrum beta-lactamase-producing Escherichia coli, vancomycin-resistant Enterococcus faecalis and Candida albicans. Bioassay-guided isolation of the secondary metabolites of A. fumigatus led to the identification of gliotoxin. Conclusion: This study demonstrated proof of principle of using bioassay-guided isolation for finding bioactive molecules.

  7. Turbulent Flame Speeds and NOx Kinetics of HHC Fuels with Contaminants and High Dilution Levels

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Eric [Texas A & M Univ., College Station, TX (United States); Krejci, Michael [Texas A & M Univ., College Station, TX (United States); Mathieu, Olivier [Texas A & M Univ., College Station, TX (United States); Vissotski, Andrew [Texas A & M Univ., College Station, TX (United States); Ravi, Sankat [Texas A & M Univ., College Station, TX (United States); Plichta, Drew [Texas A & M Univ., College Station, TX (United States); Sikes, Travis [Texas A & M Univ., College Station, TX (United States); Levacque, Anthony [Texas A & M Univ., College Station, TX (United States); Camou, Alejandro [Texas A & M Univ., College Station, TX (United States); Aul, Christopher [Texas A & M Univ., College Station, TX (United States)

    2014-01-24

    This final report documents the technical results of the 3-year project entitled, “Turbulent Flame Speeds and NOx Kinetics of HHC Fuels with Contaminants and High Dilution Levels,” funded under the NETL of DOE. The research was conducted under six main tasks: 1) program management and planning; 2) turbulent flame speed measurements of syngas mixtures; 3) laminar flame speed measurements with diluents; 4) NOx mechanism validation experiments; 5) fundamental NOx kinetics; and 6) the effect of impurities on NOx kinetics. Experiments were performed using primary constant-volume vessels for laminar and turbulent flame speeds and shock tubes for ignition delay times and species concentrations. In addition to the existing shock- tube and flame speed facilities, a new capability in measuring turbulent flame speeds was developed under this grant. Other highlights include an improved NOx kinetics mechanism; a database on syngas blends for real fuel mixtures with and without impurities; an improved hydrogen sulfide mechanism; an improved ammonia kintics mechanism; laminar flame speed data at high pressures with water addition; and the development of an inexpensive absorption spectroscopy diagnostic for shock-tube measurements of OH time histories. The Project Results for this work can be divided into 13 major sections, which form the basis of this report. These 13 topics are divided into the five areas: 1) laminar flame speeds; 2) Nitrogen Oxide and Ammonia chemical kinetics; 3) syngas impurities chemical kinetics; 4) turbulent flame speeds; and 5) OH absorption measurements for chemical kinetics.

  8. High-mobility ultrathin semiconducting films prepared by spin coating.

    Science.gov (United States)

    Mitzi, David B; Kosbar, Laura L; Murray, Conal E; Copel, Matthew; Afzali, Ali

    2004-03-18

    The ability to deposit and tailor reliable semiconducting films (with a particular recent emphasis on ultrathin systems) is indispensable for contemporary solid-state electronics. The search for thin-film semiconductors that provide simultaneously high carrier mobility and convenient solution-based deposition is also an important research direction, with the resulting expectations of new technologies (such as flexible or wearable computers, large-area high-resolution displays and electronic paper) and lower-cost device fabrication. Here we demonstrate a technique for spin coating ultrathin (approximately 50 A), crystalline and continuous metal chalcogenide films, based on the low-temperature decomposition of highly soluble hydrazinium precursors. We fabricate thin-film field-effect transistors (TFTs) based on semiconducting SnS(2-x)Se(x) films, which exhibit n-type transport, large current densities (>10(5) A cm(-2)) and mobilities greater than 10 cm2 V(-1) s(-1)--an order of magnitude higher than previously reported values for spin-coated semiconductors. The spin-coating technique is expected to be applicable to a range of metal chalcogenides, particularly those based on main group metals, as well as for the fabrication of a variety of thin-film-based devices (for example, solar cells, thermoelectrics and memory devices).

  9. Conception of PIPERADE: A high-capacity Penning-trap mass separator for high isobaric contamination at DESIR

    Energy Technology Data Exchange (ETDEWEB)

    Minaya Ramirez, E., E-mail: minaya@ipno.in2p3.fr [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Alfaurt, P.; Aouadi, M.; Ascher, P.; Blank, B. [Centre d’Etudes Nucléaires de Bordeaux-Gradignan (France); Blaum, K. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Cam, J.-F. [Laboratoire de Physique Corpusculaire, Caen (France); Chauveau, P. [Grand Accélérateur National d’Ions Lourds CEA/DSM-CNRS-IN2P3, Caen (France); Daudin, L. [Centre d’Etudes Nucléaires de Bordeaux-Gradignan (France); Delahaye, P. [Grand Accélérateur National d’Ions Lourds CEA/DSM-CNRS-IN2P3, Caen (France); Delalee, F. [Centre d’Etudes Nucléaires de Bordeaux-Gradignan (France); Dupré, P. [Centre de Sciences Nucléaires et de Sciences de la Matière, Orsay (France); El Abbeir, S.; Gerbaux, M.; Grévy, S.; Guérin, H. [Centre d’Etudes Nucléaires de Bordeaux-Gradignan (France); Lunney, D. [Centre de Sciences Nucléaires et de Sciences de la Matière, Orsay (France); Metz, F. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Naimi, S. [Riken, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Perrot, L. [Institut de Physique Nucléaire, Orsay (France); and others

    2016-06-01

    The DESIR (decay, excitation and storage of radioactive ions) facility at GANIL-SPIRAL2 will receive a large variety of exotic nuclei at low energy (up to 60 keV) with high intensities. However, the production methods of radioactive beams are non selective, limiting the purity of the beams of interest. Moreover, the high precision needed for nuclear structure and astrophysics studies using beta decay spectroscopy, laser spectroscopy and trap-based experiments at DESIR requires highly pure samples of exotic nuclei. The aim of the double-Pennig-trap mass separator PIPERADE is to deliver large and very pure samples of exotic nuclei to the different experiments in DESIR. New excitation schemes and a large inner diameter of the first trap will mitigate space charge effects to attempt trapping of up to 10{sup 5} ions per pulse. The purification cycle will be performed in a few milliseconds so that short-lived nuclei can be purified. To extract the nuclides of interest from the large amount of isobaric contaminants, a resolving power of 10{sup 5} is mandatory. Afterwards the ions of interest will be accumulated in the second trap until they constitute a sufficiently pure sample for the measurements. The status of the project is presented.

  10. Diffused sunlight driven highly synergistic pathway for complete mineralization of organic contaminants using reduced graphene oxide supported photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Babu, Sundaram Ganesh; Ramalingam Vinoth [SRM Research Institute, SRM University, Kattankulathur 603203, Chennai, Tamilnadu (India); Neppolian, Bernaurdshaw, E-mail: neppolian.b@res.srmuniv.ac.in [SRM Research Institute, SRM University, Kattankulathur 603203, Chennai, Tamilnadu (India); Dionysiou, Dionysios D. [Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Ashokkumar, Muthupandian [The School of Chemistry, University of Melbourne, Parkville, Melbourne, Victoria 3010 (Australia)

    2015-06-30

    Highlights: • Diffused sunlight is firstly used as an effective source for the degradation of organics. • More than 10 fold synergistic effect is achieved by sono-photocatalysis. • rGO enhances the degradation efficiency up to 54% as compared with CuO–TiO{sub 2} alone. • Plausible mechanism and intermediates formed are supported with experimental studies. - Abstract: Diffused sunlight is found to be an effective light source for the efficient degradation and mineralization of organic pollutant (methyl orange as a probe) by sono-photocatalytic degradation using reduced graphene oxide (rGO) supported CuO–TiO{sub 2} photocatalyst. The prepared catalysts are characterized by XRD, XPS, UV–vis DRS, PL, photoelectrochemical, SEM-EDS and TEM. A 10 fold synergy is achieved for the first time by combining sonochemical and photocatalytic degradation under diffused sunlight. rGO loading augments the activity of bare CuO–TiO{sub 2} more than two fold. The ability of rGO in storing, transferring, and shuttling electrons at the heterojunction between TiO{sub 2} and CuO facilitates the separation of photogenerated electron–hole pairs, as evidenced by the photoluminescence results. The complete mineralization of MO and the by-products within a short span of time is confirmed by TOC analysis. Further, hydroxyl radical mediated degradation under diffused sunlight is confirmed by LC–MS. This system shows similar activity for the degradation of methylene blue and 4-chlorophenol indicating the versatility of the catalyst for the degradation of various pollutants. This investigation is likely to open new possibilities for the development of highly efficient diffused sunlight driven TiO{sub 2} based photocatalysts for the complete mineralization of organic contaminants.

  11. Nanocrystalline silicon prepared at high growth rate using helium dilution

    Indian Academy of Sciences (India)

    Koyel Bhattacharya; Debajyoti Das

    2008-06-01

    Growth and optimization of the nanocrystalline silicon (nc-Si : H) films have been studied by varying the electrical power applied to the helium diluted silane plasma in RF glow discharge. Wide optical gap and conducting intrinsic nanocrystalline silicon network of controlled crystalline volume fraction and oriented crystallographic lattice planes have been obtained at a reasonably high growth rate from helium diluted silane plasma, without using hydrogen. Improving crystallinity in the network comprising ∼ 10 nm Si-nanocrystallites and contributing optical gap widening, conductivity ascending and that obtained during simultaneous escalation of the deposition rate, promises significant technological impact.

  12. Preparation for Ultra High Pure Indium Metal for Optoelectronic Applications

    Directory of Open Access Journals (Sweden)

    Shashwat V. Joshi

    2014-11-01

    Full Text Available Ultra high pure Indium metal is extensively used in optoelectronic devices. Indium and its alloys become potential candidates in aerospace, defense and communication sectors. Purification of Indium has been done by Instrolec-200 Refiner followed by Directional Melting/ Freezing and Solidification Systems. Major targeted impurities are Metallic impurities Ag, Al, As, Bi, Ca, Cu, Fe, Ga, Ge, Mg, Pb, Sb, Si, Sn, and Zn. Purified Indium is characterized by analytical techniques Inductively Coupled Plasma- Optical Emission Spectrophotometry and Inductively Coupled Plasma- Mass Spectrometry.

  13. Preparation of iron sulphides by high energy ball milling

    DEFF Research Database (Denmark)

    Lin, R.; Jiang, Jianzhong; Larsen, R.K.;

    1998-01-01

    The reaction of a powder mixture consisting of 50 a.% Fe and 50 a.% S during high energy ball milling has been studied by x-ray diffraction and Mossbauer spectroscopy. After around 19 h of milling FeS2 and FeS havebeen formed. By further milling the FeS compound becomes dominating and only Fe......S with an average crystallite size of about 10 nm was observed after milling times longer than 67 h. Mossbauer spectra obtained with applied fields show that the particles are antiferromagnetic or have a strongly canted spin structure....

  14. Influence of professional preparation and class structure on sexuality topics taught in middle and high schools.

    Science.gov (United States)

    Rhodes, Darson L; Kirchofer, Gregg; Hammig, Bart J; Ogletree, Roberta J

    2013-05-01

    This study examined the impact of professional preparation and class structure on sexuality topics taught and use of practice-based instructional strategies in US middle and high school health classes. Data from the classroom-level file of the 2006 School Health Policies and Programs were used. A series of multivariable logistic regression models were employed to determine if sexuality content taught was dependent on professional preparation and /or class structure (HE only versus HE/another subject combined). Additional multivariable logistic regression models were employed to determine if use of practice-based instructional strategies was dependent upon professional preparation and/or class structure. Years of teaching health topics and size of the school district were included as covariates in the multivariable logistic regression models. Findings indicated professionally prepared health educators were significantly more likely to teach 7 of the 13 sexuality topics as compared to nonprofessionally prepared health educators. There was no statistically significant difference in the instructional strategies used by professionally prepared and nonprofessionally prepared health educators. Exclusively health education classes versus combined classes were significantly more likely to have included 6 of the 13 topics and to have incorporated practice-based instructional strategies in the curricula. This study indicated professional preparation and class structure impacted sexuality content taught. Class structure also impacted whether opportunities for students to practice skills were made available. Results support the need for continued advocacy for professionally prepared health educators and health only courses. © 2013, American School Health Association.

  15. High Sodium Simulant Testing To Support SB8 Sludge Preparation

    Energy Technology Data Exchange (ETDEWEB)

    Newell, J. D.

    2012-09-19

    Scoping studies were completed for high sodium simulant SRAT/SME cycles to determine any impact to CPC processing. Two SRAT/SME cycles were performed with simulant having sodium supernate concentration of 1.9M at 130% and 100% of the Koopman Minimum Acid requirement. Both of these failed to meet DWPF processing objectives related to nitrite destruction and hydrogen generation. Another set of SRAT/SME cycles were performed with simulant having a sodium supernate concentration of 1.6M at 130%, 125%, 110%, and 100% of the Koopman Minimum Acid requirement. Only the run at 110% met DWPF processing objectives. Neither simulant had a stoichiometric factor window of 30% between nitrite destruction and excessive hydrogen generation. Based on the 2M-110 results it was anticipated that the 2.5M stoichiometric window for processing would likely be smaller than from 110-130%, since it appeared that it would be necessary to increase the KMA factor by at least 10% above the minimum calculated requirement to achieve nitrite destruction due to the high oxalate content. The 2.5M-130 run exceeded the DWPF hydrogen limits in both the SRAT and SME cycle. Therefore, testing of this wash endpoint was halted. This wash endpoint with this minimum acid requirement and mercury-noble metal concentration profile appears to be something DWPF should not process due to an overly narrow window of stoichiometry. The 2M case was potentially processable in DWPF, but modifications would likely be needed in DWPF such as occasionally accepting SRAT batches with undestroyed nitrite for further acid addition and reprocessing, running near the bottom of the as yet ill-defined window of allowable stoichiometric factors, potentially extending the SRAT cycle to burn off unreacted formic acid before transferring to the SME cycle, and eliminating formic acid additions in the frit slurry.

  16. Biofilm formation and sanitizer resistance of Escherichia coli 0157:H7 strains isolated from "High Event Period" meat contamination

    Science.gov (United States)

    In the meat industry, a “High Event Period” (HEP) is defined as a time period during which commercial meat plants experience a higher than usual rate of E. coli O157:H7 contamination. Genetic analysis indicated that within a HEP, most of the E. coli O157:H7 strains belong to a singular dominant str...

  17. High-Iron Biosolids Compost-Induced Changes in Lead and Arsenic Speciation and Bioaccessibility in Co-contaminated Soils

    Science.gov (United States)

    The safety of urban farming has been questioned due to the potential for contamination in urban soils. A laboratory incubation, a field trial, and a second laboratory incubation were conducted to test the ability of high-Fe biosolids–based composts to reduce the bioaccessibil...

  18. High-Iron Biosolids Compost-Induced Changes in Lead and Arsenic Speciation and Bioaccessibility in Co-contaminated Soils

    Science.gov (United States)

    The safety of urban farming has been questioned due to the potential for contamination in urban soils. A laboratory incubation, a field trial, and a second laboratory incubation were conducted to test the ability of high-Fe biosolids–based composts to reduce the bioaccessibil...

  19. Preparation and properties of highly porous, biomorphic YSZ ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Rambo, C.R.; Cao, J.; Sieber, H

    2004-10-15

    Highly porous, biomorphic YSZ (yttria-stabilized zirconia) ceramics were manufactured by infiltration of zirconium-oxychloride (ZrOCl{sub 2}{center_dot}8H{sub 2}O) sol into biological template structures derived from rattan and pine wood. 3-5 mol% yttrium nitrate (Y(NO{sub 3}){sub 3}{center_dot}5H{sub 2}O) was added to the sol to stabilize the tetragonal ZrO{sub 2} phase. After vacuum-assisted infiltration, the specimens were pyrolysed at 800 deg. C in N{sub 2} atmosphere. Repeated infiltrations and subsequent annealing in air at temperatures up to 1550 deg. C yields the burn out of the biocarbon template and resulted in the formation of biomorphous YSZ ceramics, which maintained the microstructural features of the biological preform. Depending on the type of the biological template as well as the processing parameters, biomorphic ZrO{sub 2} ceramics with an unidirected pore morphology and a large variety of microstructures can be obtained.

  20. Preparing the ATLAS Jet Trigger for High Luminosity

    CERN Document Server

    Kasieczka, G; The ATLAS collaboration

    2011-01-01

    Poster for PLHC 2011 Conference The performance of jet finding in the ATLAS trigger is presented. Results from early-2011 LHC runs are reviewed and enhancements aimed at improving performance are evaluated. The fast and precise measurement of hadronic jets with high transverse momenta in the trigger is essential to the physics goals of the ATLAS experiment. The ATLAS trigger finds jets in three stages with increasingly more complex algorithms and tighter selection criteria. Jets are found in the first stage, Level 1, from coarse granularity calorimeter towers using a sliding windows algorithm. Jets are reconstructed in the second stage, Level 2, from calorimeter cells with a cone algorithm seeded by the Level 1 jets. In the final stage - the Event Filter - topological clusters of calorimeter cells are input into the anti-kT algorithm for jet finding. This is similar to the methodology adopted by the offline analyses and improves the jet energy and angular resolution. The calorimeter is also read-out in a sing...

  1. Identification of As accumulation plant species growing on highly contaminated soils.

    Science.gov (United States)

    Gisbert, Carmina; Almela, Concepción; Vélez, Dinoraz; López-Moya, J Rafael; de Haro, Antonio; Serrano, Ramón; Montoro, Rosa; Navarro-Aviñó, Juan

    2008-01-01

    Soils from the alluvial flats of the Turia River, Valencia, Spain, which were highly contaminated by decades of industrial activity, were surveyed for native plant species that could be candidates useful in phytoremediation. Concentrations of heavy metals and arsenic (As) in soils reached 25,000 mg Kg(-1) Pb, 12,000 mg Kg(-1) Zn, 70 mg Kg(-1) Cd, and 13500 mg Kg(-1) As. The predominant vegetation was collected and species identified. Soil samples and the corresponding plant shoots were analyzed to determine the amount of As accumulated by the various plant species. Several were able to tolerate more than 1000 mg Kg(-1) As in the soil. Bassia scoparia (Chenopodiaceae) survive in soil with 8375 mg Kg(-1) As. Arsenic accumulation in shoots of the various plant species investigated ranged from 0.1 to 107 mg Kg(-1) dw. Bassia scoparia (Chenopodiaceae), Inula viscosa (Asteraceae), Solanum nigrum (Solanaceae), and Hirschfeldia incana (Brassicaceae) had the highest values for As accumulation.

  2. A study on high-speed rolling contact between a wheel and a contaminated rail

    Science.gov (United States)

    Zhao, Xin; Wen, Zefeng; Zhu, Minhao; Jin, Xuesong

    2014-10-01

    A 3-D explicit finite element model is developed to investigate the transient wheel-rail rolling contact in the presence of rail contamination or short low adhesion zones (LAZs). A transient analysis is required because the wheel passes by a short LAZ very quickly, especially at high speeds. A surface-to-surface contact algorithm (by the penalty method) is employed to solve the frictional rolling contact between the wheel and the rail meshed by solid elements. The LAZ is simulated by a varying coefficient of friction along the rail. Different traction efforts and action of the traction control system triggered by the LAZ are simulated by applying a time-dependent driving torque to the wheel axle. Structural flexibilities of the vehicle-track system are considered properly. Analysis focuses on the contact forces, creepage, contact stresses and the derived frictional work and plastic deformation. It is found that the longitudinal contact force and the maximum surface shear stress in the contact patch become obviously lower in the LAZ and much higher as the wheel re-enters the dry rail section. Consequently, a higher wear rate and larger plastic flow are expected at the location where the dry contact starts to be rebuilt. In other words, contact surface damages such as wheel flats and rail burns may come into being because of the LAZ. Length of the LAZ, the traction level, etc. are varied. The results also show that local contact surface damages may still occur as the traction control system acts.

  3. Cleanup and Dismantling of Highly Contaminated Ventilation Systems Using Robotic Tools - 13162

    Energy Technology Data Exchange (ETDEWEB)

    Chambon, Frederic [AREVA FEDERAL SERVICES, Columbia MD (United States); CIZEL, Jean-Pierre [AREVA BE/NV, Marcoule (France); Blanchard, Samuel [CEA DEN/DPAD, Marcoule (France)

    2013-07-01

    The UP1 plant reprocessed nearly 20,000 tons of used natural uranium gas cooled reactor fuel coming from the first generation of civil nuclear reactors in France. Following operating incidents in the eighties, the ventilation system of the continuous dissolution line facility was shut down and replaced. Two types of remote controlled tool carriers were developed to perform the decontamination and dismantling operations of the highly contaminated ventilation duct network. The first one, a dedicated small robot, was designed from scratch to retrieve a thick powder deposit within a duct. The robot, managed and confined by two dedicated glove boxes, was equipped for intervention inside the ventilation duct and used for carrying various cleanup and inspection tools. The second type, consisting of robotic tools developed on the base of an industrial platform, was used for the clean-up and dismantling of the ventilation duct system. Depending on the type of work to be performed, on the shape constraints of the rooms and any equipment to be dismantled, different kinds of robotic tools were developed and installed on a Brokk 40 carrier. After more than ten years of ventilation duct D and D operations at the UP1 plant, a lot of experience was acquired about remote operations. The three main important lessons learned in terms of remote controlled operation are: characterizing the initial conditions as much as reasonably possible, performing non-radioactive full scale testing and making it as simple and modular as possible. (authors)

  4. Bioremediation potential of a highly mercury resistant bacterial strain Sphingobium SA2 isolated from contaminated soil.

    Science.gov (United States)

    Mahbub, Khandaker Rayhan; Krishnan, Kannan; Megharaj, Mallavarapu; Naidu, Ravi

    2016-02-01

    A mercury resistant bacterial strain, SA2, was isolated from soil contaminated with mercury. The 16S rRNA gene sequence of this isolate showed 99% sequence similarity to the genera Sphingobium and Sphingomonas of α-proteobacteria group. However, the isolate formed a distinct phyletic line with the genus Sphingobium suggesting the strain belongs to Sphingobium sp. Toxicity studies indicated resistance to high levels of mercury with estimated EC50 values 4.5 mg L(-1) and 44.15 mg L(-1) and MIC values 5.1 mg L(-1) and 48.48 mg L(-1) in minimal and rich media, respectively. The strain SA2 was able to volatilize mercury by producing mercuric reductase enzyme which makes it potential candidate for remediating mercury. ICP-QQQ-MS analysis of Hg supplemented culture solutions confirmed that almost 79% mercury in the culture suspension was volatilized in 6 h. A very small amount of mercury was observed to accumulate in cell pellets which was also evident according to ESEM-EDX analysis. The mercuric reductase gene merA was amplified and sequenced. The deduced amino acid sequence demonstrated sequence homology with α-proteobacteria and Ascomycota group.

  5. Redox oscillation affecting mercury mobility from highly contaminated coastal sediments: a mesocosm incubation experiment

    Directory of Open Access Journals (Sweden)

    Emili A.

    2013-04-01

    Full Text Available Mercury (Hg mobility at the sediment-water interface was investigated during a laboratory incubation experiment on highly contaminated sediments (up to 23 μg g−1 of the Gulf of Trieste. Undisturbed sediment was collected in front of the Isonzo River mouth, which inflows Hg-rich suspended material originating from the Idrija (NW Slovenia mining district. Since hypoxic and anoxic conditions at the bottom are frequently observed, a redox oscillation was simulated in the laboratory at in situ temperature, using a dark flux chamber. Temporal variations of several parameters were monitored simultaneously: dissolved Hg and methylmercury (MeHg, O2, NH4+, NO3−+NO2−, PO43−, H2S, dissolved Fe and Mn, dissolved inorganic and organic carbon (DIC and DOC. Benthic fluxes of Hg and MeHg were higher under anoxic conditions while re-oxygenation caused concentrations of MeHg and Hg to rapidly drop, probably due to re-adsorption onto Fe/Mn oxyhydroxides and enhanced demethylation. Hence, during anoxic events, sediments of the Gulf of Trieste may be considered as an important source of dissolved Hg species for the water column. However, re-oxygenation of the bottom compartment mitigates Hg and MeHg release from the sediment, thus acting as a natural “defence” from possible interaction between the metal and the aquatic organisms.

  6. MICROBIAL COMMUNITY STRUCTURE IN A SHALLOW HYDROCARBON-CONTAMINATED AQUIFER ASSOCIATED WITH HIGH ELECTRICAL CONDUCTIVITY

    Science.gov (United States)

    Little is known about the complex interactions between microbial communities and electrical properties in contaminated aquifers. In order to investigate possible connections between these parameters a study was undertaken to investigate the hypothesis that the degradation of hydr...

  7. Aflatoxin contamination of red chili pepper from Bolivia and Peru, countries with high gallbladder cancer incidence rates.

    Science.gov (United States)

    Asai, Takao; Tsuchiya, Yasuo; Okano, Kiyoshi; Piscoya, Alejandro; Nishi, Carlos Yoshito; Ikoma, Toshikazu; Oyama, Tomizo; Ikegami, Kikuo; Yamamoto, Masaharu

    2012-01-01

    Chilean red chili peppers contaminated with aflatoxins were reported in a previous study. If the development of gallbladder cancer (GBC) in Chile is associated with a high level of consumption of aflatoxin-contaminated red chili peppers, such peppers from other countries having a high GBC incidence rate may also be contaminated with aflatoxins. We aimed to determine whether this might be the case for red chili peppers from Bolivia and Peru. A total of 7 samples (3 from Bolivia, 4 from Peru) and 3 controls (2 from China, 1 from Japan) were evaluated. Aflatoxins were extracted with acetonitrile:water (9:1, v/v) and eluted through an immuno-affinity column. The concentrations of aflatoxins B1, B2, G1, and G2 were measured using high-performance liquid chromatography (HPLC), and then the detected aflatoxins were identified using HPLC-mass spectrometry. In some but not all of the samples from Bolivia and Peru, aflatoxin B1 or aflatoxins B1 and B2 were detected. In particular, aflatoxin B1 or total aflatoxin concentrations in a Bolivian samples were above the maximum levels for aflatoxins in spices proposed by the European Commission. Red chili peppers from Bolivia and Peru consumed by populations having high GBC incidence rates would appear to be contaminated with aflatoxins. These data suggest the possibility that a high level of consumption of aflatoxin-contaminated red chili peppers is related to the development of GBC, and the association between the two should be confirmed by a case-control study.

  8. Using rank-order geostatistics for spatial interpolation of highly skewed data in a heavy-metal contaminated site.

    Science.gov (United States)

    Juang, K W; Lee, D Y; Ellsworth, T R

    2001-01-01

    The spatial distribution of a pollutant in contaminated soils is usually highly skewed. As a result, the sample variogram often differs considerably from its regional counterpart and the geostatistical interpolation is hindered. In this study, rank-order geostatistics with standardized rank transformation was used for the spatial interpolation of pollutants with a highly skewed distribution in contaminated soils when commonly used nonlinear methods, such as logarithmic and normal-scored transformations, are not suitable. A real data set of soil Cd concentrations with great variation and high skewness in a contaminated site of Taiwan was used for illustration. The spatial dependence of ranks transformed from Cd concentrations was identified and kriging estimation was readily performed in the standardized-rank space. The estimated standardized rank was back-transformed into the concentration space using the middle point model within a standardized-rank interval of the empirical distribution function (EDF). The spatial distribution of Cd concentrations was then obtained. The probability of Cd concentration being higher than a given cutoff value also can be estimated by using the estimated distribution of standardized ranks. The contour maps of Cd concentrations and the probabilities of Cd concentrations being higher than the cutoff value can be simultaneously used for delineation of hazardous areas of contaminated soils.

  9. Desorption electrospray ionization-high resolution mass spectrometry for the screening of veterinary drugs in cross-contaminated feedstuffs.

    Science.gov (United States)

    Seró, Raquel; Núñez, Oscar; Bosch, Jaume; Grases, José M; Rodríguez, Pilar; Moyano, Encarnacion; Galceran, Martia Teresa

    2015-09-01

    In this study, a desorption electrospray ionization-high resolution mass spectrometry (DESI-HRMS) screening method was developed for fast identification of veterinary drugs in cross-contaminated feedstuffs. The reliable detection was performed working at high resolution (70,000 full width half maximum, FWHM) using an orbitrap mass analyzer. Among the optimized DESI parameters, the solvent (acetonitrile/water, 80:20, v/v) and the sample substrate (poly-tetrafluoroethylene, PTFE) were critical to obtain the best sensitivity. To analyze the solid feed samples, different approaches were tested and a simple solid-liquid extraction and the direct analysis of an aliquot (2 μL) of the extract after letting it dry on the PTFE printed spot provided the best results. The identification of the veterinary drugs (target and non-target) in the cross-contaminated feedstuffs based on the accurate mass measurement and the isotopic pattern fit was performed automatically using a custom-made database. The positive cross-contaminated feed samples were quantified by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The results obtained demonstrate that DESI-HRMS can be proposed as a fast and suitable screening method to identify positive cross-contaminated feedstuffs reducing the number of samples to be subsequently quantified by UHPLC-MS/MS, thus improving the productivity in quality control laboratories.

  10. Characterization of Laboratory Prepared Concrete Pastes Exposed to High Alkaline and High Sodium Salt Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-06-30

    The objective of this study was to identify potential chemical degradation mechanisms for the Saltstone Disposal Unit (SDU) concretes, which over the performance life of the structures may be exposed to highly alkaline sodium salt solutions containing sulfate, hydroxide, and other potentially corrosive chemicals in salt solution and saltstone flush water, drain water, leachate and / or pore solution. The samples analyzed in this study were cement pastes prepared in the SIMCO Technologies, Inc. concrete laboratory. They were based on the paste fractions of the concretes used to construct the Saltstone Disposal Units (SDUs). SDU 1 and 4 concrete pastes were represented by the PV1 test specimens. The paste in the SDU 2, 3, 5, and 6 concrete was represented by the PV2 test specimens. SIMCO Technologies, Inc. selected the chemicals and proportions in the aggressive solutions to approximate proportions in the saltstone pore solution [2, 3, 5, and 6]. These test specimens were cured for 56 days in curing chamber before being immersed in aggressive solutions. After exposure, the samples were frozen to prevent additional chemical transport and reaction. Selected archived (retrieved from the freezer) samples were sent to the Savannah River National Laboratory (SRNL) for additional characterization using x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray (EDX) spectroscopy. Characterization results are summarized in this report. In addition, a correlation between the oxide composition of the pastes and their chemical durability in the alkaline salt solutions is provided.

  11. High risk HPV contamination of endocavity vaginal ultrasound probes: an underestimated route of nosocomial infection?

    Directory of Open Access Journals (Sweden)

    Jean-sebastien Casalegno

    Full Text Available BACKGROUND: Endocavity ultrasound is seen as a harmless procedure and has become a common gynaecological procedure. However without correct disinfection, it may result in nosocomial transmission of genito-urinary pathogens, such as high-risk Human Papillomavirus (HR-HPV. We aimed to evaluate the currently recommended disinfection procedure for covered endocavity ultrasound probes, which consists of "Low Level Disinfection" (LLD with "quaternary ammonium compounds" containing wipes. METHODS: From May to October 2011 swabs were taken from endovaginal ultrasound probes at the Gynecology Department of the Lyon University Hospital. During the first phase (May-June 2011 samples were taken after the ultrasound examination and after the LLD procedure. In a second phase (July-October 2011 swab samples were collected just before the probe was used. All samples were tested for the presence of human DNA (as a marker for a possible transmission of infectious pathogens from the genital tract and HPV DNA with the Genomica DNA microarray (35 different HPV genotypes. RESULTS: We collected 217 samples before and 200 samples after the ultrasound examination. The PCR was inhibited in two cases. Human DNA was detected in 36 (18% post-examination samples and 61 (28% pre-examination samples. After the ultrasound LLD procedure, 6 (3.0% samples contained HR-HPV types (16, 31, 2×53 and 58. Similarly, HPV was detected in 6 pre-examination samples (2.7%. Amongst these 4 (1.9% contained HR-HPV (types 53 and 70. CONCLUSION: Our study reveals that a considerable number of ultrasound probes are contaminated with human and HR-HPV DNA, despite LLD disinfection and probe cover. In all hospitals, where LLD is performed, the endovaginal ultrasound procedure must therefore be considered a source for nosocomial HR-HPV infections. We recommend the stringent use of high-level disinfectants, such as glutaraldehyde or hydrogen peroxide solutions.

  12. Preparative separation of grape skin polyphenols by high-speed counter-current chromatography.

    Science.gov (United States)

    Luo, Lanxin; Cui, Yan; Zhang, Shuting; Li, Lingxi; Li, Yuanyuan; Zhou, Peiyu; Sun, Baoshan

    2016-12-01

    To develop an efficient method for large preparation of various individual polyphenols from white grape skins (Fernão Pires; Vitis vinifera) by preparative high-speed counter-current chromatography (HSCCC) and preparative-HPLC, an optimized preparative HSCCC condition with two-phase solvent system composed of Hex-EtOAc-H2O (1:50:50, v/v) was used to separate grape skin polyphenols into various fractions. Both the tail-head and head-tail elution modes were used with a flow rate of 3.0ml/min and a rotary speed of 950rpm. Afterwards, a preparative-HPLC separation was applied to isolate individual polyphenols in each of the fractions from HSCCC. Total of 7 fractions (Fraction A to G) were obtained from grape skin extract by HSCCC. After preparative-HPLC isolation, fifteen individual compounds were obtained, most of which presented high yields and purity (all over 90%). The HSCCC method followed with preparative-HPLC appeared to be convenient and economical, constituting an efficient strategy for the isolation of grape skin polyphenols.

  13. Preparation and structural properties of thin carbon films by very-high-frequency magnetron sputtering

    Institute of Scientific and Technical Information of China (English)

    高明伟; 叶超; 王响英; 何一松; 郭佳敏; 杨培芳

    2016-01-01

    Growth and structural properties of thin a-C films prepared by the 60 MHz very-high-frequency (VHF) magnetron sputtering were investigated. The energy and flux of ions impinging the substrate were also analyzed. It is found that the thin a-C films prepared by the 60 MHz sputtering have a lower growth rate, a smooth surface, and more sp3 contents. These features are related to the higher ion energy and the lower ions flux onto the substrate. Therefore, the 60 MHz VHF sputtering is more suitable for the preparation of thin a-C film with more sp3 contents.

  14. A longitudinal examination of career preparation and adjustment during the transition from high school.

    Science.gov (United States)

    Stringer, Kate; Kerpelman, Jennifer; Skorikov, Vladimir

    2012-09-01

    Preparing for an adult career and incorporating a career into one's identity is a key task during the transition to adulthood (Erikson, 1968), and completing developmental tasks is considered a major factor in adjustment (Havinghurst, 1972). Previous research has established associations between overall career preparation in high school and adjustment soon after high school graduation. Differences in the developmental patterns of career preparation dimensions (indecision, planning, and confidence) following high school graduation also have been found. The current study builds on that prior work by examining associations between changes in the dimensions of career preparation and changes in 3 aspects of adjustment (emotional stability, social adaptation, and self-actualization) from 12th grade in high school to 4.5 years after high school graduation in a sample of 454 youths, using latent growth curve analysis. Results showed that career preparation both predicts and is predicted by adjustment. Career confidence was a particularly important predictor of adjustment. Both 12th grade career confidence and changes in confidence over time predicted changes in adjustment and adjustment 4.5 years post-high school. In an alternative model, an increase in emotional stability was predictive of higher career confidence and lower indecision. Results are discussed in the context of developmental theories and the notion that adjustment and career are interrelated processes.

  15. Biofilm formation and sanitizer resistance of Escherichia coli O157:H7 strains isolated from "high event period" meat contamination.

    Science.gov (United States)

    Wang, Rong; Kalchayanand, Norasak; King, David A; Luedtke, Brandon E; Bosilevac, Joseph M; Arthur, Terrance M

    2014-11-01

    In the meat industry, a "high event period" (HEP) is defined as a time period during which commercial meat plants experience a higher than usual rate of Escherichia coli O157:H7 contamination. Genetic analysis indicated that within a HEP, most of the E. coli O157:H7 strains belong to a singular dominant strain type. This was in disagreement with the current beef contamination model stating that contamination occurs when incoming pathogen load on animal hides, which consists of diverse strain types of E. coli O157:H7, exceeds the intervention capacity. Thus, we hypothesize that the HEP contamination may be due to certain in-plant colonized E. coli O157:H7 strains that are better able to survive sanitization through biofilm formation. To test our hypothesis, a collection of 45 E. coli O157:H7 strains isolated from HEP beef contamination incidents and a panel of 47 E. coli O157:H7 strains of diverse genetic backgrounds were compared for biofilm formation and sanitizer resistance. Biofilm formation was tested on 96-well polystyrene plates for 1 to 6 days. Biofilm cell survival and recovery growth after sanitization were compared between the two strain collections using common sanitizers, including quaternary ammonium chloride, chlorine, and sodium chlorite. No difference in "early stage" biofilms was observed between the two strain collections after incubation at 22 to 25°C for 1 or 2 days. However, the HEP strains demonstrated significantly higher potency of "mature" biofilm formation after incubation for 4 to 6 days. Biofilms of the HEP strains also exhibited significantly stronger resistance to sanitization. These data suggest that biofilm formation and sanitization resistance could have a role in HEP beef contamination by E. coli O157:H7, which highlights the importance of proper and complete sanitization of food contact surfaces and food processing equipment in commercial meat plants.

  16. Lambda-Cyhalothrin Nanosuspension Prepared by the Melt Emulsification-High Pressure Homogenization Method

    OpenAIRE

    Zhenzhong Pan; Bo Cui; Zhanghua Zeng; Lei Feng; Guoqiang Liu; Haixin Cui; Hongyu Pan

    2015-01-01

    The nanosuspension of 5% lambda-cyhalothrin with 0.2% surfactants was prepared by the melt emulsification-high pressure homogenization method. The surfactants composition, content, and homogenization process were optimized. The anionic surfactant (1-dodecanesulfonic acid sodium salt) and polymeric surfactant (maleic rosin-polyoxypropylene-polyoxyethylene ether sulfonate) screened from 12 types of commercially common-used surfactants were used to prepare lambda-cyhalothrin nanosuspension with ...

  17. A validated high performance thin layer chromatography method for determination of yohimbine hydrochloride in pharmaceutical preparations

    OpenAIRE

    Badr, Jihan M.

    2013-01-01

    Background: Yohimbine is an indole alkaloid used as a promising therapy for erectile dysfunction. A number of methods were reported for the analysis of yohimbine in the bark or in pharmaceutical preparations. Materials and Method: In the present work, a simple and sensitive high performance thin layer chromatographic method is developed for determination of yohimbine (occurring as yohimbine hydrochloride) in pharmaceutical preparations and validated according to International Conference of Ha...

  18. Synthetic process for preparation of high surface area electroactive compounds for battery applications

    Energy Technology Data Exchange (ETDEWEB)

    Evenson, Carl; Mackay, Richard

    2013-07-23

    A process is disclosed for the preparation of electroactive cathode compounds useful in lithium-ion batteries, comprising exothermic mixing of low-cost precursors and calcination under appropriate conditions. The exothermic step may be a spontaneous flameless combustion reaction. The disclosed process can be used to prepare any lithium metal phosphate or lithium mixed metal phosphate as a high surface area single phase compound.

  19. Reclamation of zinc-contaminated soil using a dissolved organic carbon solution prepared using liquid fertilizer from food-waste composting.

    Science.gov (United States)

    Chiang, Po-Neng; Tong, Ou-Yang; Chiou, Chyow-San; Lin, Yu-An; Wang, Ming-Kuang; Liu, Cheng-Chung

    2016-01-15

    A liquid fertilizer obtained through food-waste composting can be used for the preparation of a dissolved organic carbon (DOC) solution. In this study, we used the DOC solutions for the remediation of a Zn-contaminated soil (with Zn concentrations up to 992 and 757 mg kg(-1) in topsoil and subsoil, respectively). We then determined the factors that affect Zn removal, such as pH, initial concentration of DOC solution, and washing frequency. Measurements using a Fourier Transform infrared spectrometer (FT-IR) revealed that carboxyl and amide were the major functional groups in the DOC solution obtained from the liquid fertilizer. Two soil washes using 1,500 mg L(-1) DOC solution with a of pH 2.0 at 25°C removed about 43% and 21% of the initial Zn from the topsoil and subsoil, respectively. Following this treatment, the pH of the soil declined from 5.4 to 4.1; organic matter content slightly increased from 6.2 to 6.5%; available ammonium (NH4(+)-N) content increased to 2.4 times the original level; and in the topsoil, the available phosphorus content and the exchangeable potassium content increased by 1.65 and 2.53 times their initial levels, respectively.

  20. Analysis and discussion of different methods of artificial ice-high specimen preparation

    Institute of Scientific and Technical Information of China (English)

    ShuJuan Zhang; Wei Ma; ZhiZhong Sun; HaiMin Du

    2014-01-01

    Because ice-high foundation soil is widely distributed in permafrost regions, the correct preparation of ice-high specimens is of critical interest in engineering design for foundation stability. Past research has shown that the uniaxial compression strength of ice-high frozen soils changes as the ice or total water content increases;the differences of different methods of specimen preparation are analyzed here and the advantages and disadvantages of them are presented. It is confirmed that the role of crushed ice is significantly different from that of naturally frozen ice in frozen soils, and the size and amount of crushed ice will influence the strength and deformation mechanism of frozen soils. Therefore, it is strongly recommended that when a ice-high specimen is artificially prepared, the ice should be frozen through natural means and not be replaced with crushed ice.

  1. Detection of lead (pb and aluminum (Al metal as contaminant in food prepared by using locally manufactured cooked pots (Hala in Kosti City, Sudan

    Directory of Open Access Journals (Sweden)

    EI Salah

    2015-06-01

    Full Text Available The objectives of this study are to assess the quantities of Aluminu m; lead released into the food from locally manufactured cooked pots (Aluminium pots in Kosti market. Seven types of pots (Pistons, Cartels, Kettles, Kettles + trays, Pepsi cans, Atmonia and Steel which is locally manufactured cooked pots (Hala were used. Amount of Al and Pb that leaked into the food from locally manufactured cooked pots were assessed by using Atomic Absorption Spectroscopy. The results were indicated that highly significance amount of Aluminum and lead which were leaked into the food that prepared by locally manufactured cooked pots (Hala.The analysis of urine for 10 selected randomly individuals that used locally manufactured cooked pots (Hala for preparation their food were indicated highly amount of Aluminum and Lead in their urine. DOI: http://dx.doi.org/10.3126/ije.v4i2.12621 International Journal of Environment Vol.4(2 2015: 19-26

  2. Experimental investigations of the neutron contamination in high-energy photon fields at medical linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Brunckhorst, Elin

    2009-02-26

    The scope of this thesis was to develop a device for the detection of the photoneutron dose inside the high-energy photon field. The photoneutron contamination of a Siemens PRIMUS linear accelerator was investigated in detail in its 15 MV photon mode. The experimental examinations were performed with three ionisation chambers (a tissue equivalent chamber, a magnesium chamber and a {sup 10}B-coated magnesium chamber) and two types of thermoluminescence detectors (enriched with {sup 6}Li and {sup 7}Li, respectively). The detectors have different sensitivities to photons and neutrons and their combination allows the dose separation in a mixed neutron/photon field. The application of the ionisation chamber system, as well as the present TLD system for photoneutron detection in high-energy photon beams is a new approach. The TLD neutron sensitivity was found to be too low for a measurement inside the open photon field and the further investigation focused on the ionisation chambers. The three ionisation chambers were calibrated at different photon and neutron sources and a the borated magnesium chamber showed a very high response to thermal neutrons. For a cross check of the calibration, the three chambers were also used for dose separation of a boron neutron capture therapy beam where the exact determination of the thermal neutron dose is essential. Very accurate results were achieved for the thermal neutron dose component. At the linear accelerator the chamber system was reduced to a paired chamber system utilising the two magnesium chambers, since the fast neutron component was to small to be separated. The neutron calibration of the three chambers could not be applied, instead a conversion of measured thermal neutron signal by the borated chamber to Monte Carlo simulated total neutron dose was performed. Measurements for open fields in solid water and liquid water were performed with the paired chamber system. In larger depths the neutron dose could be determined

  3. Pollution of soil and groundwater from infiltration of highly contaminated stormwater - a case study

    DEFF Research Database (Denmark)

    Mikkelsen, P.S.; Häfliger, M.; Ochs, M.

    1997-01-01

    A surface and a sub-surface infiltration system that received runoff water from trafficked roads for several decades was dug up and the contamination with heavy metals, PAH and AOX was investigated. Most measured solid phase concentrations exceeded background concentrations in nearby surface soils...... and subsurface sediments and some even exceeded guidelines fixed to preserve the fertility of soil. However, the contamination decreased rapidly with depth. None of the measured metal concentrations in simulated soil solutions exceeded defined drinking water quality standards. Surprisingly, the surface...... and the sub-surface infiltration system seemed to be equally good at retaining pollution. This indicates that the runoff sludge found in such infiltration systems plays an important role both as a source and a sorbent for stormwater contaminants. The study does not point at a considerable risk for groundwater...

  4. Effect of Air Pollution, Contamination and High Altitude on Bronchial Asthma

    Directory of Open Access Journals (Sweden)

    Nesriene El margoushy*, Mohamad El Nashar**, Hatem Khairy*, Nihad El Nashar*, Hala Mohamad

    2013-01-01

    Full Text Available Epidemiological studies have shown that the prevalence of asthma has risen dramatically worldwide and evidence suggests that environmental factors have an important role in the etiology of the disease. Most respiratory diseases are caused by airborne agents. Our lungs are uniquely vulnerable to contamination from the air we breathe. Air pollution exposure is associated with increased asthma and allergy morbidity and is a suspected contributor to the increasing prevalence of allergic conditions. Observational studies continue to strengthen the association between air pollution and allergic respiratory disease. The effects of air pollution should be viewed in two different groups: healthy people and people with chronic heart or lung disease. Although the fundamental causes of asthma are not completely understood, the strongest risk factors for developing asthma are inhaled asthma triggers. These include: indoor allergens (for example house dust mites in bedding, carpets and stuffed furniture, pollution and pet dander, outdoor allergens (such as pollens and moulds, tobacco smoke and chemical irritants in the workplace. Other triggers can include cold air, extreme emotional arousal such as anger or fear, and physical exercise. Even certain medications can trigger asthma such as aspirin and other non-steroid anti-inflammatory drugs, and beta-blockers. Urbanization has also been associated with an increase in asthma; however the exact nature of this relationship is unclear. Medication is not the only way to control asthma. It is also important to avoid asthma triggers - stimuli that irritate and inflame the airways. Prevalence of asthma is generally low within the Middle East, although high rates have been recorded in the Kingdom of Saudi Arabia, Kuwait, Lebanon, and Israel. The prevalence of asthma and asthma-related symptoms is high among 16- to 18-year-old adolescents in Saudi Arabia, and the symptoms are more common in boys than in girls

  5. Preparing Students for College: The Implementation and Impact of the Early College High School Model

    Science.gov (United States)

    Edmunds, Julie A.; Bernstein, Lawrence; Glennie, Elizabeth; Willse, John; Arshavsky, Nina; Unlu, Fatih; Bartz, Deborah; Silberman, Todd; Scales, W. David; Dallas, Andrew

    2010-01-01

    As implemented in North Carolina, Early College High Schools are small, autonomous schools designed to increase the number of students who graduate from high school and are prepared for postsecondary education. Targeted at students who are underrepresented in college, these schools are most frequently located on college campuses and are intended…

  6. Extraction and Purification of Glucoraphanin by Preparative High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Lee, Iris; Boyce, Mary C.

    2011-01-01

    A student activity that focuses on the isolation of glucoraphanin from broccoli using preparative high-performance liquid chromatography (HPLC) is presented here. Glucoraphanin is a glucosinolate, whose byproducts are known to possess anticancer properties. It is present naturally at high levels in broccoli and other "Brassica" vegetables. This…

  7. Preparing Students for College: The Implementation and Impact of the Early College High School Model

    Science.gov (United States)

    Edmunds, Julie A.; Bernstein, Lawrence; Glennie, Elizabeth; Willse, John; Arshavsky, Nina; Unlu, Fatih; Bartz, Deborah; Silberman, Todd; Scales, W. David; Dallas, Andrew

    2010-01-01

    As implemented in North Carolina, Early College High Schools are small, autonomous schools designed to increase the number of students who graduate from high school and are prepared for postsecondary education. Targeted at students who are underrepresented in college, these schools are most frequently located on college campuses and are intended…

  8. Extraction and Purification of Glucoraphanin by Preparative High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Lee, Iris; Boyce, Mary C.

    2011-01-01

    A student activity that focuses on the isolation of glucoraphanin from broccoli using preparative high-performance liquid chromatography (HPLC) is presented here. Glucoraphanin is a glucosinolate, whose byproducts are known to possess anticancer properties. It is present naturally at high levels in broccoli and other "Brassica" vegetables. This…

  9. Highly conductive free standing polypyrrole films prepared by freezing interfacial polymerization.

    Science.gov (United States)

    Qi, Guijin; Huang, Liyan; Wang, Huiliang

    2012-08-25

    Highly conductive free standing polypyrrole (PPy) films were prepared by a novel freezing interfacial polymerization method. The films exhibit metallic luster and electrical conductivity up to 2000 S cm(-1). By characterizing with SEM, FTIR, Raman and XRD, the high conductivity is attributed to the smooth surface, higher conjugation length and more ordered molecular structure of PPy.

  10. Use of biological meshes for abdominal wall reconstruction in highly contaminated fields

    Institute of Scientific and Technical Information of China (English)

    Andrea; Cavallaro; Emanuele; Lo; Menzo; Maria; Di; Vita; Antonio; Zanghì; Vincenzo; Cavallaro; Pier; Francesco; Veroux; Alessandro; Cappellani

    2010-01-01

    Abdominal wall defects and incisional hernias represent a challenging problem. In particular, when a synthetic mesh is applied to contaminated wounds, its removal is required in 50%-90% of cases. Biosynthetic meshes are the newest tool available to surgeons and they could have a role in ventral hernia repair in a potential-ly contaminated field. We describe the use of a sheet of bovine pericardium graft in the reconstruction of abdominal wall defect in two patients. Bovine pericardium graft was placed in th...

  11. Denitrifying bacteria from the genus Rhodanobacter dominate bacterial communities in the highly contaminated subsurface of a nuclear legacy waste site.

    Science.gov (United States)

    Green, Stefan J; Prakash, Om; Jasrotia, Puja; Overholt, Will A; Cardenas, Erick; Hubbard, Daniela; Tiedje, James M; Watson, David B; Schadt, Christopher W; Brooks, Scott C; Kostka, Joel E

    2012-02-01

    The effect of long-term mixed-waste contamination, particularly uranium and nitrate, on the microbial community in the terrestrial subsurface was investigated at the field scale at the Oak Ridge Integrated Field Research Challenge (ORIFRC) site in Oak Ridge, TN. The abundance, community composition, and distribution of groundwater microorganisms were examined across the site during two seasonal sampling events. At representative locations, subsurface sediment was also examined from two boreholes, one sampled from the most heavily contaminated area of the site and another from an area with low contamination. A suite of DNA- and RNA-based molecular tools were employed for community characterization, including quantitative PCR of rRNA and nitrite reductase genes, community composition fingerprinting analysis, and high-throughput pyrotag sequencing of rRNA genes. The results demonstrate that pH is a major driver of the subsurface microbial community structure and that denitrifying bacteria from the genus Rhodanobacter (class Gammaproteobacteria) dominate at low pH. The relative abundance of bacteria from this genus was positively correlated with lower-pH conditions, and these bacteria were abundant and active in the most highly contaminated areas. Other factors, such as the concentration of nitrogen species, oxygen level, and sampling season, did not appear to strongly influence the distribution of Rhodanobacter bacteria. The results indicate that these organisms are acid-tolerant denitrifiers, well suited to the acidic, nitrate-rich subsurface conditions, and pH is confirmed as a dominant driver of bacterial community structure in this contaminated subsurface environment.

  12. Targeting Safer Aquifer At A Highly Arsenic Contaminated Community; South-Western Bangladesh

    Science.gov (United States)

    Tauhid-Ur-Rahman, Md.

    2010-05-01

    The depositional pattern, geochemistry and mineralogy of the Arsenic (As) contaminated sediments along with the chemistry of groundwaters extracted from the Holocene deposit of an As hotspot, Kalaroa, Southwestern Bangladesh have been investigated in this study. These were done to elucidate a unified view that could explain the accumulation and distribution of As on the sediment surface and its subsequent release into the groundwater. Such view of As distribution mainly helped to find out eventually the possible existence of any safer aquifer that could provide adequate potable water to that targeted community. Two key geochemical parameters, the reaction rate Kr and the partition coefficient, Kd were found to be very promising in explaining the As release mechanism. Showing the realistic natural biotite dissolution process, the in-situ Kr that was derived by applying inverse mass balance model (2.72 × 10-16 /sec), was found to be slower by only three orders of magnitude than that was determined with the laboratory study (3.19×10-13 /sec). A parametric predictor equation, that can calculate the partition coefficient Kd based on the aquifer sediment's minerals such as Fe and Al contents along with pore-water pH was developed in this study. Another Kd model based on the diffuse double layer surface complexation theory has also been developed to compare the appropriateness of the parametric Kd model. These two models were compared with the in-situ based field Kd data and were found in a good agreement. Integrating those two essential geochemical parameters (Kd and Kr), a 1D-Finite Difference numerical model was applied to observe and evaluate the As pollution scenario for the studied Holocene aquifer. The simulation showed very promising results introducing the idea that the deeper aquifer's groundwaters would be remained safe against being contaminated with high As in future, due to the presence of a number of encouraging factors. The most significant among such

  13. Highly porous activated carbons prepared from carbon rich Mongolian anthracite by direct NaOH activation

    Science.gov (United States)

    Byamba-Ochir, Narandalai; Shim, Wang Geun; Balathanigaimani, M. S.; Moon, Hee

    2016-08-01

    Highly porous activated carbons (ACs) were prepared from Mongolian raw anthracite (MRA) using sodium hydroxide as an activation agent by varying the mass ratio (powdered MRA/NaOH) as well as the mixing method of chemical agent and powdered MRA. The specific BET surface area and total pore volume of the prepared MRA-based activated carbons (MACs) are in the range of 816-2063 m2/g and of 0.55-1.61 cm3/g, respectively. The pore size distribution of MACs show that most of the pores are in the range from large micropores to small mesopores and their distribution can be controlled by the mass ratio and mixing method of the activating agent. As expected from the intrinsic property of the MRA, the highly graphitic surface morphology of prepared carbons was confirmed from Raman spectra and transmission electron microscopy (TEM) studies. Furthermore the FTIR and XPS results reveal that the preparation of MACs with hydrophobic in nature is highly possible by controlling the mixing conditions of activating agent and powdered MRA. Based on all the results, it is suggested that the prepared MACs could be used for many specific applications, requiring high surface area, optimal pore size distribution, proper surface hydrophobicity as well as strong physical strength.

  14. Simple room-temperature preparation of high-yield large-area graphene oxide.

    Science.gov (United States)

    Huang, N M; Lim, H N; Chia, C H; Yarmo, M A; Muhamad, M R

    2011-01-01

    Graphene has attracted much attention from researchers due to its interesting mechanical, electrochemical, and electronic properties. It has many potential applications such as polymer filler, sensor, energy conversion, and energy storage devices. Graphene-based nanocomposites are under an intense spotlight amongst researchers. A large amount of graphene is required for preparation of such samples. Lately, graphene-based materials have been the target for fundamental life science investigations. Despite graphene being a much sought-after raw material, the drawbacks in the preparation of graphene are that it is a challenge amongst researchers to produce this material in a scalable quantity and that there is a concern about its safety. Thus, a simple and efficient method for the preparation of graphene oxide (GO) is greatly desired to address these problems. In this work, one-pot chemical oxidation of graphite was carried out at room temperature for the preparation of large-area GO with ~100% conversion. This high-conversion preparation of large-area GO was achieved using a simplified Hummer's method from large graphite flakes (an average flake size of 500 μm). It was found that a high degree of oxidation of graphite could be realized by stirring graphite in a mixture of acids and potassium permanganate, resulting in GO with large lateral dimension and area, which could reach up to 120 μm and ~8000 μm(2), respectively. The simplified Hummer's method provides a facile approach for the preparation of large-area GO.

  15. Remote Methodology used at B Plant Hanford to Map High Radiation and Contamination Fields and Document Remaining Hazards

    Energy Technology Data Exchange (ETDEWEB)

    SIMMONS, F.M.

    2000-01-01

    A remote radiation mapping system using the Gammacam{trademark} (AIL Systems Inc. Trademark) with real-time response was used in deactivating the B Plant at Hanford to produce digitized images showing actual radiation fields and dose rates. Deployment of this technology has significantly reduced labor requirements, decreased personnel exposure, and increased the accuracy of the measurements. Personnel entries into the high radiation/contamination areas was minimized for a dose savings of 30 Rem (.3 Seivert) and a cost savings of $640K. In addition, the data gathered was utilized along with historical information to estimate the amount of remaining hazardous waste in the process cells. The B Plant facility is a canyon facility containing 40 process cells which were used to separate cesium and strontium from high level waste. The cells and vessels are contaminated with chemicals used in the separation and purification processes. Most of the contaminants have been removed but the residual contamination from spills in the cells and heels in the tanks contribute to the localized high radioactivity. The Gammacam{trademark} system consists of a high density terbium-activated scintillating glass detector coupled with a digitized video camera. Composite images generated by the system are presented in pseudo color over a black and white image. Exposure times can be set from 10 milliseconds to 1 hour depending on the field intensity. This information coupled with process knowledge is then used to document the hazardous waste remaining in each cell. Additional uses for this radiation mapping system would be in support of facilities stabilization and deactivation activities at Hanford or other DOE sites. The system is currently scheduled for installation and mapping of the U Plant in 1999. This system is unique due to its portability and its suitability for use in high dose rate areas.

  16. Preparation of high dispersion and high performance PtRu/CNTs catalyst by an organic colloid method

    Institute of Scientific and Technical Information of China (English)

    王宁卡特; 刘军民; 廖世军; V.Birss

    2006-01-01

    A high dispersion and high performance PtRu catalyst supported on carbon nanotubes was prepared by an organic colloid method. The particle size of the active components could be as small as 1.0 nm,the active surface area was about 466 m2/g(Pt). The catalytic activity toward anodic oxidation of methanol was about 3 ~ 4 times higher than that of Johnson Matthey PtRu/XC-72R catalyst. The single testing showed that the performance of the prepared catalyst was higher than that of the commercial one.

  17. [Contaminated heparins].

    Science.gov (United States)

    Monneret, C

    2008-08-01

    In January 2008, following the detection of severe allergic reaction, several batches of heparins were removed from the United-States market. Although less dramatic, comparable side effects were also reported in Germany but not in France despite the fact that low-weight heparins, obtained from contaminated batches of unfractionated heparins, were used to limit shortage. So far, tainted injectable heparin has been linked to over 80 deaths in the USA. Analyses demonstrated that such tainted heparins were contaminated by high levels of chondroïtin persulfate (5-20%), a cheaper hemi-synthetic product. All batches were furnished by several Chinese chemical industries, China representing 50% of all heparins produced worldwide. Thus, contamination of the heparin supply is a worldwide problem. Following this event, the efficiency of the quality insurance, particularly analytical controls before proceeding, remains questionable. The strict respect of the pharmaceutical chain is urgently required to avoid any kind of quality problem in the future.

  18. High-temperature treatment for efficient drying of bread rye and reduction of fungal contaminants

    DEFF Research Database (Denmark)

    Kristensen, E.F.; Elmholt, S.; Thrane, Ulf

    2005-01-01

    Mycotoxin-producing fungi are natural contaminants of cereals and their toxins are harmful to humans and animals. Ochratoxin A (OTA) is among the most important. Heat treatment by drum drying does not eliminate already formed mycotoxins but the technique can reduce the number of viable fungi on t...

  19. Exploring the Behaviour of Emerging Contaminants in the Water Cycle using the Capabilities of High Resolution Mass Spectrometry.

    Science.gov (United States)

    Hollender, Juliane; Bourgin, Marc; Fenner, Kathrin B; Longrée, Philipp; Mcardell, Christa S; Moschet, Christoph; Ruff, Matthias; Schymanski, Emma L; Singer, Heinz P

    2014-11-01

    To characterize a broad range of organic contaminants and their transformation products (TPs) as well as their loads, input pathways and fate in the water cycle, the Department of Environmental Chemistry (Uchem) at Eawag applies and develops high-performance liquid chromatography (LC) methods combined with high-resolution tandem mass spectrometry (HRMS/MS). In this article, the background and state-of-the-art of LC-HRMS/MS for detection of i) known targets, ii) suspected compounds like TPs, and iii) unknown emerging compounds are introduced briefly. Examples for each approach are taken from recent research projects conducted within the department. These include the detection of trace organic contaminants and their TPs in wastewater, pesticides and their TPs in surface water, identification of new TPs in laboratory degradation studies and ozonation experiments and finally the screening for unknown compounds in the catchment of the river Rhine.

  20. Bayesian based design of real-time sensor systems for high-risk indoor contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Sreedharan, Priya [Univ. of California, Berkeley, CA (United States)

    2007-01-01

    The sudden release of toxic contaminants that reach indoor spaces can be hazardousto building occupants. To respond effectively, the contaminant release must be quicklydetected and characterized to determine unobserved parameters, such as release locationand strength. Characterizing the release requires solving an inverse problem. Designinga robust real-time sensor system that solves the inverse problem is challenging becausethe fate and transport of contaminants is complex, sensor information is limited andimperfect, and real-time estimation is computationally constrained.This dissertation uses a system-level approach, based on a Bayes Monte Carloframework, to develop sensor-system design concepts and methods. I describe threeinvestigations that explore complex relationships among sensors, network architecture,interpretation algorithms, and system performance. The investigations use data obtainedfrom tracer gas experiments conducted in a real building. The influence of individual sensor characteristics on the sensor-system performance for binary-type contaminant sensors is analyzed. Performance tradeoffs among sensor accuracy, threshold level and response time are identified; these attributes could not be inferred without a system-level analysis. For example, more accurate but slower sensors are found to outperform less accurate but faster sensors. Secondly, I investigate how the sensor-system performance can be understood in terms of contaminant transport processes and the model representation that is used to solve the inverse problem. The determination of release location and mass are shown to be related to and constrained by transport and mixing time scales. These time scales explain performance differences among different sensor networks. For example, the effect of longer sensor response times is comparably less for releases with longer mixing time scales. The third investigation explores how information fusion from heterogeneous sensors may improve the sensor

  1. An analysis of high-performing science students' preparation for collegiate science courses

    Science.gov (United States)

    Walter, Karen

    This mixed-method study surveyed first year high-performing science students who participated in high-level courses such as International Baccalaureate (IB), Advanced Placement (AP), and honors science courses in high school to determine their perception of preparation for academic success at the collegiate level. The study used 52 students from an honors college campus and surveyed the students and their professors. The students reported that they felt better prepared for academic success at the collegiate level by taking these courses in high school (pstudent GPA with honors science courses (n=55 and Pearson's r=-0.336), while AP courses (n=47 and Pearson's r=0.0016) and IB courses (n=17 and Pearson's r=-0.2716) demonstrated no correlation between perception of preparation and GPA. Students reported various themes that helped or hindered their perception of academic success once at the collegiate level. Those themes that reportedly helped students were preparedness, different types of learning, and teacher qualities. Students reported in a post-hoc experience that more lab time, rigorous coursework, better teachers, and better study techniques helped prepare them for academic success at the collegiate level. Students further reported on qualities of teachers and teaching that helped foster their academic abilities at the collegiate level, including teacher knowledge, caring, teaching style, and expectations. Some reasons for taking high-level science courses in high school include boosting GPA, college credit, challenge, and getting into better colleges.

  2. Isolation and purification of heroin from heroin street samples by preparative high performance liquid chromatography.

    Science.gov (United States)

    Guo, Zhen; Zheng, Hui; Lu, Yanzhen; Wei, Yun

    2012-09-10

    The present study established a novel method using preparative high performance liquid chromatography to isolate and purify heroin·HCl from heroin street samples to be used as a reference standard. Different kinds of mobile phases and columns were used, ultimately the mobile phase consisting of hexane-isopropanol-methanol (65:28:7, v/v) and the SIL preparative column prepared in laboratory were selected as the final condition. Heroin was further purified by the drowning-out crystallization method using isopropanol-methanol (50:1, v/v) and hexane as drowning-out anti-solvents and salting-out agents, respectively. The purity was assessed by analytical high performance liquid chromatography and the confirmation of the chemical structure was performed by IR and NMR. About 110.7mg of heroin·HCl at a purity of over 99.52% was obtained from 180mg of heroin street samples which contained 156.15mg of heroin·HCl component by preparative high performance liquid chromatography. This method is suitable for preparing heroin standards in forensic science area.

  3. Novel technique to suppress hydrocarbon contamination for high accuracy determination of carbon content in steel by FE-EPMA

    Science.gov (United States)

    Yamashita, Takako; Tanaka, Yuji; Yagoshi, Masayasu; Ishida, Kiyohito

    2016-07-01

    In multiphase steels, control of the carbon contents in the respective phases is the most important factor in alloy design for achieving high strength and high ductility. However, it is unusually difficult to determine the carbon contents in multiphase structures with high accuracy by electron probe microanalysis (EPMA) due to the unavoidable effect of hydrocarbon contamination during measurements. We have investigated new methods for suppressing hydrocarbon contamination during field emission (FE) EPMA measurements as well as a conventional liquid nitrogen trap. Plasma cleaner inside the specimen chamber results in a improvement of carbon-content determination by point analysis, increasing precision tenfold from the previous 0.1 mass%C to 0.01 mass%C. Stage heating at about 100 °C dramatically suppresses contamination growth during continuous point measurement and mapping. By the combination of above two techniques, we successfully visualized the two-dimensional carbon distribution in a dual-phase steel. It was also noted that the carbon concentrations at the ferrite/martensite interfaces were not the same across all interfaces, and local variation was observed. The developed technique is expected to be a powerful tool for understanding the mechanisms of mechanical properties and microstructural evolution, thereby contributing to the design of new steel products with superior properties.

  4. Reduction of Cadmium Uptake of Rice Plants Using Soil Amendments in High Cadmium Contaminated Soil: A Pot Experiment

    Directory of Open Access Journals (Sweden)

    Dian Siswanto

    2013-05-01

    Full Text Available The aims of this study were to investigate the effect of agricultural residues on reducing cadmium uptake in rice plants. The rice plants growing on no cadmium/free cadmium soils (N, Cd soils (Cds, and Cd soils each amended with 1% w/w of coir pith (CP, coir pith modified with sodium hydroxide (CPm and corncob (CC under high cadmium contaminated soil with an average 145 mg Cd kg-1 soil were investigated. The results showed that the cumulative transpiration of rice grown in various treatments under high cadmium contaminated soil followed the order: Cds > CPm ≥ CP ≥ CC. These transpirations directly influenced cadmium accumulation in shoots and husks of rice plants. The CC and CP seemed to work to reduce the cadmium uptake by rice plants indicated by accumulated cadmium in the husk that were 2.47 and 7.38 mg Cd kg-1 dry weight, respectively. Overall, transpiration tended to drive cadmium accumulation in plants for rice grown in high cadmium contaminated soil. The more that plants uptake cadmium, the lower cadmium that remains in the soil.

  5. Novel technique to suppress hydrocarbon contamination for high accuracy determination of carbon content in steel by FE-EPMA.

    Science.gov (United States)

    Yamashita, Takako; Tanaka, Yuji; Yagoshi, Masayasu; Ishida, Kiyohito

    2016-07-19

    In multiphase steels, control of the carbon contents in the respective phases is the most important factor in alloy design for achieving high strength and high ductility. However, it is unusually difficult to determine the carbon contents in multiphase structures with high accuracy by electron probe microanalysis (EPMA) due to the unavoidable effect of hydrocarbon contamination during measurements. We have investigated new methods for suppressing hydrocarbon contamination during field emission (FE) EPMA measurements as well as a conventional liquid nitrogen trap. Plasma cleaner inside the specimen chamber results in a improvement of carbon-content determination by point analysis, increasing precision tenfold from the previous 0.1 mass%C to 0.01 mass%C. Stage heating at about 100 °C dramatically suppresses contamination growth during continuous point measurement and mapping. By the combination of above two techniques, we successfully visualized the two-dimensional carbon distribution in a dual-phase steel. It was also noted that the carbon concentrations at the ferrite/martensite interfaces were not the same across all interfaces, and local variation was observed. The developed technique is expected to be a powerful tool for understanding the mechanisms of mechanical properties and microstructural evolution, thereby contributing to the design of new steel products with superior properties.

  6. Accumulation of heavy metals in oil-contaminated peat soils

    Science.gov (United States)

    Vodyanitskii, Yu. N.; Savichev, A. T.; Trofimov, S. Ya.; Shishkonakova, E. A.

    2012-10-01

    X-ray fluorescence and X-ray radiometry represent easy and simple methods to determine concentrations of heavy metals in the ash of peat soils contaminated with oil and can be applied for soil monitoring purposes. Oil spills on peat bogs produce two contamination zones differing in the composition of heavy metals. In the zone of primary contamination, the peat surface is covered by a bitumen crust with V, Ni, Sr, Ba, Ce, and La accumulating there. This zone adjoins the zone of secondary peat contamination, where heavy alkaline-earth metals (Sr, Ba) and lanthanides (Ce and La) are accumulated to a lesser extent. Biological preparations recommended for remediation of oil-contaminated peat soils should be tolerant to high concentrations of heavy metals, particularly, V, Ni, and Ba that are present in the oil contaminated soils in relatively high amounts.

  7. Methodological bases of modern theory of physical preparation of sportsmen of high class

    Directory of Open Access Journals (Sweden)

    Osipov V.M.

    2012-08-01

    Full Text Available Modern presentations and walkthrough of theory of physical preparation of sportsmen of high class are considered. It is well-proven that the empiric way of development of theory of the sporting training lost the theoretical and practical meaningfulness already a long ago. Achievements of soviet and Russian scientific school are selected. Found out contradiction in the looks of modern specialists to the problem of method of the sporting training. It is set that development of modern theory of physical preparation must be interlinked with the design of the systems of organism. Marked on the necessity of creation of general model on the basis of combination of knowledges of biochemistry, physicists, biomechanics, physiology, psychology, sport theories. Directions of development of innovative technologies of control of physical preparedness, facilities and methods of physical development, plans of physical preparation of sportsmen of high class are recommended.

  8. Preparation methodology and possible treatments for improved ceramics for high voltage vacuum applications

    CERN Document Server

    Tan, J

    1998-01-01

    The flashover characteristics of an insulator bridged high voltage vacuum gap can play an important role in the overall performance of a high voltage device, for example in the extreme environments of high energy particle accelerators. The detailed preparation of the insulators is, at present, governed by the commercial production methods and by standard bulk cleaning processes, which for a particular application may be far from optimum. The influence of the mechanical preparation, thermal history and particular cleaning technique have been investigated for commercially available alumina samples, with measurement of surface characteristics by scanning electron microscopy and laser diffraction, measurement of the secondary electron emission curve and analysis of the high voltage performance with the possibility of applied fields up to 200kV/cm. The results of the different measurements are discussed in the overall context of the problems encountered in the full sized high voltage devices, and suggestions are m...

  9. Reclamation of zinc-contaminated soil using a dissolved organic carbon solution prepared using liquid fertilizer from food-waste composting

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Po-Neng [Experimental Forest, National Taiwan University, Chushan, Nantou County, 55750, Taiwan (China); Tong, Ou-Yang [Department of Environment Engineering, College of the Environment and Ecology, and The Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, Xiamen University, Xiamen (China); Chiou, Chyow-San; Lin, Yu-An [Department of Environmental Engineering, National Ilan University, Ilan 26047, Taiwan (China); Wang, Ming-Kuang [Department of Animal Science, National Ilan University, Ilan 26047, Taiwan (China); Liu, Cheng-Chung, E-mail: ccliu@niu.edu.tw [Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan (China)

    2016-01-15

    Highlights: • Nitrogen, phosphorus, and potassium contents in soil are substantially increased after the DOC washing. • The removal of Zn is dominated by proton replacement at pH 2.0, rather than by complexation with DOC. • The removal of Zn is dominated by DOC complexation between pH 3.0 and pH 5.0. - Abstract: A liquid fertilizer obtained through food-waste composting can be used for the preparation of a dissolved organic carbon (DOC) solution. In this study, we used the DOC solutions for the remediation of a Zn-contaminated soil (with Zn concentrations up to 992 and 757 mg kg{sup −1} in topsoil and subsoil, respectively). We then determined the factors that affect Zn removal, such as pH, initial concentration of DOC solution, and washing frequency. Measurements using a Fourier Transform infrared spectrometer (FT-IR) revealed that carboxyl and amide were the major functional groups in the DOC solution obtained from the liquid fertilizer. Two soil washes using 1,500 mg L{sup −1} DOC solution with a of pH 2.0 at 25 °C removed about 43% and 21% of the initial Zn from the topsoil and subsoil, respectively. Following this treatment, the pH of the soil declined from 5.4 to 4.1; organic matter content slightly increased from 6.2 to 6.5%; available ammonium (NH{sub 4}{sup +}-N) content increased to 2.4 times the original level; and in the topsoil, the available phosphorus content and the exchangeable potassium content increased by 1.65 and 2.53 times their initial levels, respectively.

  10. Preparation and optimization of glyceryl behenate-based highly porous pellets containing cilostazol.

    Science.gov (United States)

    Hwang, Kyu-Mok; Byun, Woojin; Cho, Cheol-Hee; Park, Eun-Seok

    2016-11-03

    The aim of this study was to prepare a highly porous multiparticulate dosage form containing cilostazol for gastroretentive drug delivery. The floating pellets were prepared with glyceryl behenate as a matrix former and camphor as a sublimating agent by extrusion/spheronization and sublimation under vacuum. Granules prepared with sublimation at 60 °C displayed a slower dissolution rate and smoother surface morphology than those prepared at lower temperatures. This was unexpected as the reported melting point of glyceryl behenate is higher than 69 °C. The DSC study revealed that melting began at a lower temperature owing to the multicomponent property of glyceryl behenate, which led to a sintering effect. The prepared pellets were spherical with unimodal size distribution. They also had porous structures with increased porosity, which led to immediate buoyancy. As cilostazol is a hydrophobic drug that has an erosion-based release mechanism, drug release profile was highly correlated with the percentage of disintegrated pellets. Various excipients were added to the glyceryl behenate-based formulation to increase the floating duration. When hydroxyethyl cellulose was added to the glyceryl behenate-based pellets, acceptable dissolution rate and buoyancy were acquired. This system could potentially be used for gastroretentive delivery of various hydrophobic drugs, which was generally considered difficult.

  11. Preparation of high selective molecularly imprinted polymers for tetracycline by precipitation polymerization

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    High selective molecularly imprinted polymers (MIPs) for tetracycline have been prepared by precipitation polymerization.Effects of monomer and solvent, the ratio of monomer and template and the characterization of the polymer were investigated by frontal chromatography and selectivity experiment. The results clearly indicated that the polymer, which had the highest molecular recognition abilities for tetracycline antibiotics, had been received.

  12. The Preparation of Highly Motivated and Professionally Competent Teachers in Initial Teacher Education

    Science.gov (United States)

    Tang, Sylvia Y. F.; Wong, Angel K. Y.; Cheng, May M. H.

    2015-01-01

    Education systems around the world need to recruit highly motivated individuals to become teachers and prepare professionally competent teacher education graduates to take up these broadened and deepened roles and responsibilities with a deep and lasting engagement to the profession. This article reports on a mixed-methods study that examines…

  13. Malthematical Preparation versus Career Aspirations: A Study of Wyoming's 1978 High School Seniors.

    Science.gov (United States)

    Kansky, Bob; Olson, Melfried

    This report provides a general description of the mathematical programs pursued by students in Wyoming's public schools, an evaluation of the adequacy of the high school mathematical preparation of college-bound students relative to the occupational aspirations of those students, and a measure of the extent to which students are aware of the…

  14. Employment Preparation and Life Skill Development Initiatives for High School Students with Emotional and Behavioral Disabilities

    Science.gov (United States)

    Swank, Jacqueline M.; Huber, Peter

    2013-01-01

    Employment preparation and life skill development are crucial in assisting students identified as having emotional and behavioral disabilities with successfully transitioning to adulthood following high school. This article outlines four initiatives that a school counselor developed with other school personnel to promote work skills, life skills,…

  15. Success in Introductory College Physics: The Role of High School Preparation.

    Science.gov (United States)

    Sadler, Philip M.; Tai, Robert H.

    2001-01-01

    Examines the extent to which a high school physics course prepares students for college physics success. In this study of 1,933 introductory college physics students, demographic and schooling factors account for a large fraction of the variation in college physics grades at 18 colleges and universities from around the nation. (Author/SAH)

  16. Extruded foams prepared from high amylose starch with sodium stearate to form amylose inclusion complexes

    Science.gov (United States)

    Starch foams were prepared from high amylose corn starch in the presence and absence of sodium stearate and PVOH to determine how the formation of amylose-sodium stearate inclusion complexes and the addition of PVOH would affect foam properties. Low extrusion temperatures were used, and X-ray diffra...

  17. Starch aerogel beads obtained from inclusion complexes prepared from high amylose starch and sodium palmitate

    Science.gov (United States)

    Starch aerogels are a class of low density highly porous renewable materials currently prepared from retrograded starch gels and are of interest for their good surface area, porosity, biocompatibility, and biodegradability. Recently, we have reported on starches containing amylose-fatty acid salt h...

  18. Surfactant-free Preparation of Highly Stable Zwitterionic Poly(amido amine) Nanogels with Minimal Cytotoxicity

    NARCIS (Netherlands)

    Ekkelenkamp, A.E.; Jansman, M.M.T.; Roelofs-Haarhuis, H.M.; Engbersen, J.F.J.; Paulusse, J.M.J.

    2016-01-01

    Narrowly dispersed zwitterionic poly(amido amine) (PAA) nanogels with a diameter of approximately 100 nm were prepared by a high-yielding and surfactant-free, inverse nanoprecipitation of PAA polymers. The resulting, negatively charged, nanogels (PAA-NG1) were functionalized with N,N-dimethylethylen

  19. High-Pressure Preparation of High-Density Cu2ZnSnS4 Materials

    Science.gov (United States)

    Yi-Ming, Li; Li-Xia, Qiu; Zhan-Hui, Ding; Yong-Feng, Li; Bin, Yao; Zhen-Yu, Xiao; Pin-Wen, Zhu

    2016-07-01

    Not Available Supported by the National Natural Science Foundation of China under Grant Nos 10874178, 11074093, 61205038 and 11274135, the National Found for Fostering Talents of Basic Science under Grant No J1103202, the Ph.D. Programs Foundation of Ministry of Education of China under Grant No 20120061120011, the Open Project of State Key Laboratory of Superhard Materials of Jilin University, and the State Key Laboratory of Inorganic Synthesis and Preparative Chemistry of Jilin University.

  20. Highly porous activated carbons prepared from carbon rich Mongolian anthracite by direct NaOH activation

    Energy Technology Data Exchange (ETDEWEB)

    Byamba-Ochir, Narandalai [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of); Shim, Wang Geun [Department of Polymer Science and Engineering, Sunchon National University, 255 Jungang-Ro, Suncheon, Jeollanam-Do 57922 (Korea, Republic of); Balathanigaimani, M.S., E-mail: msbala@rgipt.ac.in [Department of Chemical Engineering, Rajiv Gandhi Institute of Petroleum Technology, Ratapur Chowk, Rae Bareli, 229316 Uttar Pradesh (India); Moon, Hee, E-mail: hmoon@jnu.ac.kr [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of)

    2016-08-30

    Highlights: • Highly porous carbon materials from Mongolian anthracite by chemical activation. • Cheaper and eco-friendly activation process has been employed. • Activated carbons with graphitic structure and energetically heterogeneous surface. • Surface hydrophobicity and porosity of the activated carbons can be controlled. - Abstract: Highly porous activated carbons (ACs) were prepared from Mongolian raw anthracite (MRA) using sodium hydroxide as an activation agent by varying the mass ratio (powdered MRA/NaOH) as well as the mixing method of chemical agent and powdered MRA. The specific BET surface area and total pore volume of the prepared MRA-based activated carbons (MACs) are in the range of 816–2063 m{sup 2}/g and of 0.55–1.61 cm{sup 3}/g, respectively. The pore size distribution of MACs show that most of the pores are in the range from large micropores to small mesopores and their distribution can be controlled by the mass ratio and mixing method of the activating agent. As expected from the intrinsic property of the MRA, the highly graphitic surface morphology of prepared carbons was confirmed from Raman spectra and transmission electron microscopy (TEM) studies. Furthermore the FTIR and XPS results reveal that the preparation of MACs with hydrophobic in nature is highly possible by controlling the mixing conditions of activating agent and powdered MRA. Based on all the results, it is suggested that the prepared MACs could be used for many specific applications, requiring high surface area, optimal pore size distribution, proper surface hydrophobicity as well as strong physical strength.

  1. Facile preparation of superhydrophobic surface with high adhesive forces based carbon/silica composite films

    Indian Academy of Sciences (India)

    Ruanbing Hu; Guohua Jiang; Xiaohong Wang; Xiaoguang Xi; Rijing Wang

    2013-11-01

    Glass substrates modified by carbon/silica composites are fabricated through a two-step process for the preparation of a superhydrophobic surface (water contact angle ≥ 150°). Carbon nanoparticles were first prepared through a deposition process on glass using a hydrothermal synthesis route, then the glass was modified by SiO2 using the hydrolysis reaction of tetraethylorthosilicate at room temperature. It is not only a facile method to create a superhydrophobic surface, but also helps to form a multi-functional surface with high adhesive forces.

  2. Magnetic properties of nanocrystalline pyrrhotite prepared by high-energy milling

    DEFF Research Database (Denmark)

    Balaz, P.; Godocikova, E.; Alacova, A.;

    2004-01-01

    The nanocrystalline pyrrhotite was prepared by high-energy milling of lead sulphide with elemental Fe acting as reducing element. X-ray diffractometry, Mossbauer spectroscopy and VSM magnetometry were used to determine the properties of nanocrystalline iron sulphide prepared by the corresponding...... mechanochemical reaction. Pyrrhotite Fe1-xS together with the residual Fe metal were identified by the X-ray diffractometry. The kinetic studies performed by Mossbauer spectroscopy and VSM magnetometry allowed us to follow in more details the progress of the nanocrystalline magnetic phase formation during...... the milling....

  3. High Pressure Air Jet in the Endoscopic Preparation Room: Risk of Noise Exposure on Occupational Health

    OpenAIRE

    King-Wah Chiu; Lung-Sheng Lu; Cheng-Kun Wu

    2015-01-01

    After high-level disinfection of gastrointestinal endoscopes, they are hung to dry in order to prevent residual water droplets impact on patient health. To allow for quick drying and clinical reuse, some endoscopic units use a high pressure air jet (HPAJ) to remove the water droplets on the endoscopes. The purpose of this study was to evaluate the excessive noise exposure with the use of HPAJ in endoscopic preparation room and to investigate the risk to occupational health. Noise assessment w...

  4. Preparation of Multiwall Carbon Nanotubes-supported High Loading Platinum for Vehicular PEMFC Application

    Institute of Scientific and Technical Information of China (English)

    Bing ZHANG; Li Juan CHEN; Kai Yong GE; Yan Chuan GUO; Bi Xian PENG

    2005-01-01

    Multiwall carbon nanotube-supported Pt (Pt/MWNTs) catalysts with high dispersion and high loading of Pt were prepared by chemical reduction method and the loading of Pt got to 40wt%. The average diameter of Pt nanoparticles on MWNTs was about 3.5 nm. When the hydrogen and air were used as reactant gases for PEMFC, Pt/MWNTs catalysts showed significantly higher performance than the Pt/XC-72 (carbon black) catalysts.

  5. Preparation and Characterization of High-Purity Metal Fluorides for Photonic Applications

    Science.gov (United States)

    2011-01-01

    Photonics Technol. Lett., 4 446–8 (1992). 8D. F. Anderson, “ Cerium Fluoride – A Scintillator for High-Rate Applica- tions,” Nucl. Instrum. Meth. Phys... Cerium Doped Heavy Metal Fluoride Glasses, a Possible Alternative for Electromagnetic Calorimetry,” Instrum. Meth. Phys. Res. A, 380, 524–36 (1996). 10J...Preparation and Characterization of High-Purity Metal Fluorides for Photonic Applications* Wendy M. Patterson,‡,† Peter C. Stark,§ Thomas M. Yoshida

  6. NUMERICAL SIMULATION OF EXTRUSION OF COMPOSITE POWDERS PREPARED BY HIGH ENERGY MILLING

    Institute of Scientific and Technical Information of China (English)

    X.Q. Li; W.P. Chen; W. Xia; Q.L. Zhu; Y.Y. Li; E.D. Wang

    2004-01-01

    Based on the characteristic of high energy milling and the micromechanics of composite material, a plastic constitutive equation is implemented for milled composite powders. To check the equation, the extrusion of Ti/Al composite powders prepared by high energy milling was simulated. It was from the numerical analysis that the predicted extrusion pressure mounted up with milling time and extrusion ratio increasing,which was perfect agreement with experimental results.

  7. Preparation and investigation of ultrafine-grained tungsten carbide with high hardness and fracture toughness

    Science.gov (United States)

    Chuvil'deev, V. N.; Blagoveshchenskii, Yu. V.; Sakharov, N. V.; Boldin, M. S.; Nokhrin, A. V.; Isaeva, N. V.; Shotin, S. V.; Lopatin, Yu. G.; Smirnova, E. S.

    2015-07-01

    High-density samples of ultrafine-grained tungsten carbide with high hardness (up to 31-34 GPa) and increased fracture toughness (up to 5.2-6.4 MPa m1/2) are obtained using the technology of electropulse plasma sintering. The influence of the initial size of nanoparticles of α-WC prepared by plasmachemical synthesis on the density, structural parameters, and mechanical properties of tungsten carbide is investigated.

  8. Systematic approach to preparing ceramic-glass composites with high translucency for dental restorations.

    Science.gov (United States)

    Yoshimura, Humberto N; Chimanski, Afonso; Cesar, Paulo F

    2015-10-01

    Ceramic composites are promising materials for dental restorations. However, it is difficult to prepare highly translucent composites due to the light scattering that occurs in multiphase ceramics. The objective of this work was to verify the effectiveness of a systematic approach in designing specific glass compositions with target properties in order to prepare glass infiltrated ceramic composites with high translucency. First it was necessary to calculate from literature data the viscosity of glass at the infiltration temperature using the SciGlass software. Then, a glass composition was designed for targeted viscosity and refractive index. The glass of the system SiO2-B2O3-Al2O3-La2O3-TiO2 prepared by melting the oxide raw materials was spontaneously infiltrated into porous alumina preforms at 1200°C. The optical properties were evaluated using a refractometer and a spectrophotometer. The absorption and scattering coefficients were calculated using the Kubelka-Munk model. The light transmittance of prepared composite was significantly higher than a commercial ceramic-glass composite, due to the matching of glass and preform refractive indexes which decreased the scattering, and also to the decrease in absorption coefficient. The proposed systematic approach was efficient for development of glass infiltrated ceramic composites with high translucency, which benefits include the better aesthetic performance of the final prosthesis. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  9. Success in introductory college physics: The role of high school preparation

    Science.gov (United States)

    Sadler, Philip M.; Tai, Robert H.

    2001-03-01

    High school teachers and college physics professors differ in their beliefs concerning the extent to which a high school physics course prepares students for college physics success. In this study of 1,933 introductory college physics students, demographic and schooling factors account for a large fraction of the variation in college physics grades at 18 colleges and universities from around the nation. Controlling for student backgrounds, taking a high school physics course has a modestly positive relationship with the grade earned in introductory college physics. More rigorous preparation, including calculus and 2 years of high school physics, predicts higher grades. Students who had high school courses that spent more time on fewer topics, concepts, problems, and labs performed much better in college than those who raced through more content in a textbook-centered course. College professors should recognize that a substantial fraction of the variation observed in the performance of students they teach can be explained by the range in effectiveness of their pre-college preparation, not simply innate ability. Although students without a high school physics course often do well in college physics, they are more likely to be academically stronger, with more educated parents, having previously taken calculus, and taking physics in their sophomore or junior year in college.

  10. Preparation of high-performance ultrafine-grained AISI 304L stainless steel under high temperature and pressure

    Directory of Open Access Journals (Sweden)

    Peng Wang

    2016-08-01

    Full Text Available Bulk ultra-fine grained (UFG AISI 304L stainless steel with excellent mechanical properties was prepared by a high-temperature and high-pressure (HTHP method using nanocrystalline AISI 304L stainless steel powders obtained from ball milling. Samples were sintered in high-pressure conditions using the highest martensite content of AISI 304L stainless steel powders milled for 25 h. Analyses of phase composition and grain size were accomplished by X-ray diffraction and Rietveld refinement. By comparing the reverse martensite transformation under vacuum and HTHP treat, we consider that pressure can effectively promote the change in the process of transformation. Compared with the solid-solution-treated 304L, the hardness and yield strength of the samples sintered under HTHP are considerably higher. This method of preparation of UFG bulk stainless steel may be widely popularised and used to obtain UFG metallic materials with good comprehensive performance.

  11. Success in introductory college physics: The role of gender, high school preparation, and student learning perceptions

    Science.gov (United States)

    Chen, Jean Chi-Jen

    Physics is fundamental for science, engineering, medicine, and for understanding many phenomena encountered in people's daily lives. The purpose of this study was to investigate the relationships between student success in college-level introductory physics courses and various educational and background characteristics. The primary variables of this study were gender, high school mathematics and science preparation, preference and perceptions of learning physics, and performance in introductory physics courses. Demographic characteristics considered were age, student grade level, parents' occupation and level of education, high school senior grade point average, and educational goals. A Survey of Learning Preference and Perceptions was developed to collect the information for this study. A total of 267 subjects enrolled in six introductory physics courses, four algebra-based and two calculus-based, participated in the study conducted during Spring Semester 2002. The findings from the algebra-based physics courses indicated that participant's educational goal, high school senior GPA, father's educational level, mother's educational level, and mother's occupation in the area of science, engineering, or computer technology were positively related to performance while participant age was negatively related. Biology preparation, mathematics preparation, and additional mathematics and science preparation in high school were also positively related to performance. The relationships between the primary variables and performance in calculus-based physics courses were limited to high school senior year GPA and high school physics preparation. Findings from all six courses indicated that participant's educational goal, high school senior GPA, father's educational level, and mother's occupation in the area of science, engineering, or computer technology, high school preparation in mathematics, biology, and the completion of additional mathematics and science courses were

  12. An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions

    Energy Technology Data Exchange (ETDEWEB)

    Ruan, Guihua, E-mail: guihuaruan@hotmail.com [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004 (China); Wu, Zhenwei; Huang, Yipeng; Wei, Meiping; Su, Rihui [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Du, Fuyou, E-mail: dufu2005@126.com [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004 (China)

    2016-04-22

    A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of N{sub α}-benzoyl-L-arginine ethyl ester to N{sub α}-benzoyl-L-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast and easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas. - Graphical abstract: Schematic illustration of preparation of hypercrosslinking polyHIPE immobilized enzyme reactor for on-column protein digestion. - Highlights: • A reactor was prepared and used for enzyme immobilization and continuous on-column protein digestion. • The new polyHIPE IMER was quite suit for protein digestion with good properties. • On-column digestion revealed that the IMER was easy regenerated by HCl without any structure destruction.

  13. Adaptation of the bivalve embryotoxicity assay for the high throughput screening of emerging contaminants in Mytilus galloprovincialis.

    Science.gov (United States)

    Fabbri, Rita; Montagna, Michele; Balbi, Teresa; Raffo, Enrico; Palumbo, Franca; Canesi, Laura

    2014-08-01

    Emerging contaminants (such as Endocrine disrupting chemicals-EDCs, brominated and perfluorinated compounds-BFRs and PFCs, pharmaceuticals) are chemicals currently not included in regulatory monitoring programs, and whose fate and biological impacts are poorly understood. Assessment of ecosystem health with respect to these chemicals is of particular concern also in the marine environment: in this respect, data on the effects on early life stages are important to establish the sensitivity of marine species. In this work, the acute (48 h) bivalve embryo toxicity test was applied for screening the developmental effects of different emerging contaminants in the Mediterranean mussel Mytilus galloprovincialis. The assay was adapted to 96-microwell plates, and standardized in order to obtain to normal D-shaped larvae with acceptability of test results based on negative control and positive control (copper) comparable with those reported in literature for Mytilus spp. The effects of different model compounds representative of EDCs (Nonylphenol-NP and Bisphenol A-BPA), BFRs (Tetrabromobisphenol A-TBBPA), PFCs (perfluorooctanoid acid-PFOA and perfluorooctane sulphonate-PFOAS) and pharmaceuticals (Ibuprofen-IBU, Diclofenac-DCF, Bezafibrate-BEZA) in a wide concentration range (0.01-0.1-1-10-100-1000 μg/L) were evaluated. The assay proved as a sensitive tool for high throughput screening of emerging contaminants in a marine species, leading to production of significant amounts of data that may be useful for regulatory purposes.

  14. High levels of inorganic arsenic in rice in areas where arsenic-contaminated water is used for irrigation and cooking.

    Science.gov (United States)

    Rahman, M Azizur; Hasegawa, H

    2011-10-15

    Rice is the staple food for the people of arsenic endemic South (S) and South-East (SE) Asian countries. In this region, arsenic contaminated groundwater has been used not only for drinking and cooking purposes but also for rice cultivation during dry season. Irrigation of arsenic-contaminated groundwater for rice cultivation has resulted high deposition of arsenic in topsoil and uptake in rice grain posing a serious threat to the sustainable agriculture in this region. In addition, cooking rice with arsenic-contaminated water also increases arsenic burden in cooked rice. Inorganic arsenic is the main species of S and SE Asian rice (80 to 91% of the total arsenic), and the concentration of this toxic species is increased in cooked rice from inorganic arsenic-rich cooking water. The people of Bangladesh and West Bengal (India), the arsenic hot spots in the world, eat an average of 450g rice a day. Therefore, in addition to drinking water, dietary intake of arsenic from rice is supposed to be another potential source of exposure, and to be a new disaster for the population of S and SE Asian countries. Arsenic speciation in raw and cooked rice, its bioavailability and the possible health hazard of inorganic arsenic in rice for the population of S and SE Asia have been discussed in this review. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Interpretation of high-resolution low-altitude helicopter magnetometer surveys over sites contaminated with unexploded ordnance

    Science.gov (United States)

    Billings, Stephen; Wright, David

    2010-12-01

    Throughout the world, millions of acres of potentially productive land are contaminated with unexploded ordnance due to either past conflicts or to military training activities. Low-level helicopter magnetometry (HeliMag) is currently being used to rapidly survey large areas and identify regions that are potentially clear of hazardous munitions. One configuration currently in use comprises seven cesium vapor magnetometers, horizontally spaced 1.5 m apart and mounted on a boom several meters in front of a Bell 206L helicopter. Magnetometer data are collected at 400 Hz at altitudes as low as 1.5 m above the ground along transects spaced 7 meters apart. From this dense, high-resolution data, potential metallic targets as small as a 60 mm mortar are identified using manual and/or automatic target picking methods. The target picks are then used to estimate densities of potential contamination. 100% detection is generally not feasible, so that HeliMag is usually applied in a characterization rather than in a clearance mode. We describe a HeliMag survey collected over a UXO contaminated site at Yekau Lake, near Edmonton, Canada. The objective was to identify the location and extent of an 11.5 pound bomb target area at a former training range. The target density estimates derived from manual picks were strongly influenced by geology and clutter and did not reflect the underlying density of ordnance and ordnance related clutter. By fitting a dipole model to each target pick, and comparing it to the expected response of the target item, we could estimate the density of objects with similar size/shape to an 11.5 pound bomb. This analysis clearly identified an area of elevated contamination in the same region where 11.5 pound bombs were found during ground reconnaissance. In summary, the new methodology significantly improves the interpretability of HeliMag data when used for UXO site assessment.

  16. Assessment of fly ash-aided phytostabilisation of highly contaminated soils after an 8-year field trial

    Energy Technology Data Exchange (ETDEWEB)

    Lopareva-Pohu, Alena [Universite Lille Nord de France, Lille (France); Groupe ISA, Equipe Sols et Environnement, Laboratoire Genie Civil et geoEnvironnement Lille Nord de France EA 4515, 48 boulevard Vauban, 59046 Lille Cedex (France); Universite du Littoral-Cote d' Opale, Unite de Chimie Environnementale et Interactions sur le Vivant (UCEIV), EA4492, Maison de la Recherche en Environnement Industriel de Dunkerque 2, Avenue Maurice Schumann, 59140 Dunkerque (France); Pourrut, Bertrand; Waterlot, Christophe [Universite Lille Nord de France, Lille (France); Groupe ISA, Equipe Sols et Environnement, Laboratoire Genie Civil et geoEnvironnement Lille Nord de France EA 4515, 48 boulevard Vauban, 59046 Lille Cedex (France); Garcon, Guillaume [Universite Lille Nord de France, Lille (France); Universite du Littoral-Cote d' Opale, Unite de Chimie Environnementale et Interactions sur le Vivant (UCEIV), EA4492, Maison de la Recherche en Environnement Industriel de Dunkerque 2, Avenue Maurice Schumann, 59140 Dunkerque (France); Bidar, Geraldine; Pruvot, Christelle [Universite Lille Nord de France, Lille (France); Groupe ISA, Equipe Sols et Environnement, Laboratoire Genie Civil et geoEnvironnement Lille Nord de France EA 4515, 48 boulevard Vauban, 59046 Lille Cedex (France); Shirali, Pirouz [Universite Lille Nord de France, Lille (France); Universite du Littoral-Cote d' Opale, Unite de Chimie Environnementale et Interactions sur le Vivant (UCEIV), EA4492, Maison de la Recherche en Environnement Industriel de Dunkerque 2, Avenue Maurice Schumann, 59140 Dunkerque (France); Douay, Francis, E-mail: f.douay@isa-lille.fr [Universite Lille Nord de France, Lille (France); Groupe ISA, Equipe Sols et Environnement, Laboratoire Genie Civil et geoEnvironnement Lille Nord de France EA 4515, 48 boulevard Vauban, 59046 Lille Cedex (France)

    2011-01-01

    Sustainable management of large surface areas contaminated with trace elements is a real challenge, since currently applied remediation techniques are too expensive for these areas. Aided phytostabilisation appears to be a cost efficient technique to reduce metal mobility in contaminated soils and contaminated particle spread. In this context, this study aimed at evaluating the long-term efficiency of aided phytostabilisation on former agricultural soils highly contaminated with trace elements. The influence of afforestation and fly ash amendments to reduce metal mobility was investigated. Before being planted with a tree mix, the study site was divided into three plots: a reference plot with no amendment, the second amended with silico-aluminous fly ash and the third with sulfo-calcic fly ash. After eight years, some soil physico-chemical parameters, including cadmium (Cd), lead (Pb) and zinc (Zn) extractability were modified. In particular, pH decreased on the whole site while organic carbon content increased. The alteration of these parameters influencing trace element mobility is explained by afforestation. Over time, concentrations of CaCl{sub 2}-extractable metals increased and were correlated with the soil pH decrease. In the amended soils, extractable Cd, Pb and Zn concentrations were lower than in the reference soil. The results indicated that the two fly ashes buffered natural soil acidification due to vegetation development and limited trace element mobility and thus could limit their bioavailability. For long-term phytostabilisation, special attention should be focused on the soil pH, metal mobility and phytoavailability analysis. - Research Highlights: {yields} Afforestation leads to soil pH decrease and organic carbon content increase. {yields} Fly ashes buffered natural soil acidification. {yields} Fly ashes limited metal mobility.

  17. A galvanic replacement route to prepare strongly fluorescent and highly stable gold nanodots for cellular imaging.

    Science.gov (United States)

    Wang, Chuanxi; Wang, Yu; Xu, Lin; Shi, Xiaodong; Li, Xiangwei; Xu, Xiaowei; Sun, Hongchen; Yang, Bai; Lin, Quan

    2013-02-11

    Fluorescent gold nanodots (GNDs) are an important kind of nanoprobes. Herein, the application of galvanic replacement for the preparation of fluorescent GNDs is reported. Using presynthesized and size-controlled Ag nanodots (Ag NDs) as templates, the as-prepared GNDs have strong fluorescence (quantum yields ~10%) with high stability and surface bioactivity. The resultant GNDs show excellent photoluminescence properties with high photo-, time-, metal-, and pH-stability, which are attributed to the protective surface layer of glutathione (GSH) and the presence of Au(I)-S complexes on the surface of the gold core. GSH, a naturally occurring and readily available tripeptide with carboxyl and amino functional groups, allows good dispersion of the as-prepared GNDs in aqueous solution and favorable biocompatibility. These advantages, combined with their small size, mean that the as-prepared GNDs have potential application in biological labeling, especially as a DNA probe for the specific detection of nucleic acids. In this study, the CAL-27 cells are used as a model to evaluate the fluorescence imaging of GNDs.

  18. High Performance Protein-Coated Microcrystals of Rhizomucor miehei Lipase: Preparation and Application for Organic Synthesis.

    Science.gov (United States)

    Kazlauskas, Simas; Kiriliauskaitė, Vita; Kalėdienė, Lilija; Bendikienė, Vida

    2015-05-01

    The goal of obtaining enzyme forms with higher catalytic activity, greater stability, and improved reusability has been pursued for the last few decades. Various novel biocatalyst designs have been created, and protein-coated microcrystals (PCMCs) are one of them. PCMC is an enzyme immobilization method based on simultaneous precipitation of protein and carrier, forming micron-sized enzyme-coated crystals. Highly active Rhizomucor miehei lipase (RML) PCMCs were prepared by immobilizing the protein onto K2SO4 as a carrier salt in acetone as a precipitating solvent. The formation of RML PCMCs was confirmed by scanning electron microscopy. Preparation of RML PCMCs was optimized by response surface methodology (RSM). Obtained PCMCs were found to be more active and stable during p-nitrophenyl palmitate hydrolysis in n-hexane, compared to liquid RML. The enzymatic activity and temperature optimum increased from 0.011 U/mg(soluble) lipase to 8.70 U/mg(immobilized) lipase and from 30 to 37 °C, respectively. Additionally, the ability of RML PCMCs to catalyze flavor ester 2-phenethyl octanoate synthesis was investigated. Some reaction parameters were optimized, resulting in 80 % conversion within 1 h with an enhanced reusability, compared to commercial immobilized RML preparation. Thus, PCMCs offer a cheap and effective technology for obtaining highly active lipase preparations for biocatalysis in organic media.

  19. Fast-response high-resolution temperature sonde aimed at contamination-free profile observations

    Directory of Open Access Journals (Sweden)

    K. Shimizu

    2010-08-01

    Full Text Available An innovative temperature sonde, equipped with an ultra thin tungsten wire, has been developed to meet the scientific requirements suitable for climate change research. The response time, shorter than 40 ms achieved at the altitude of 30 km, enables the temperature observations with the radiation correction of less than 0.4 K in the whole observation range. Test flights during the development stage reveal significant artificial perturbations in the observed temperature profiles. They are identified as the thermal contamination arising primarily from radiosonde package box with some additional effect from the launching balloon. The modification of the sensor mount successfully removed the contribution from the former effect. On the other hand, some filtering procedure need to be applied to remove the latter, although the use of a long suspension line will be effective to reduce the noise. There remain unavoidable small fluctuations (less than 0.4 K that are brought about by the solid angle modulation of the illumination against the sensor body in the daytime. While conventional radiation correction may unintentionally have taken a part of such contaminations into account, they may not be properly corrected in existing radiosonde data, as the origin of errors has not been identified. Our tungsten sonde that scarcely relies on the ambiguous correction procedures is ideal for serving as an international reference.

  20. Ionic-liquid-based dispersive liquid-liquid microextraction for high-throughput multiple food contaminant screening.

    Science.gov (United States)

    Ho, Yee-Man; Tsoi, Yeuk-Ki; Leung, Kelvin Sze-Yin

    2013-12-01

    This paper describes an innovation of dispersive liquid-liquid microextraction enabling multiple-component analysis of eight high-priority food contaminants in two chemically distinctive families: Sudan dyes and phthalate plasticizers. To provide convenient sample handling for solid and solid-containing matrices, a modified dispersive liquid-liquid microextraction procedure used an extractant precoated frit to perform simultaneous filtration, solvent mixing, and phase dispersion in one simple step. A binary ionic liquid extractant system was carefully tuned to deliver high quality analysis based only on affordable LC with diode array detector instrumentation. The method is comprehensively validated for robust quantification with good precision (6.9-9.8% RSD) in a linear 2-1000 μg/L range. Having accomplished enrichment factors up to 451, the treatment enables sensitive detection at 0.09-1.01 μg/L levels. Analysis of six high-risk solid condiments and sauces further verified its practical applicability within a 70-120% recovery range. Compared to other approaches, the current dispersive liquid-liquid microextraction treatment offers major advantages in terms of minimal solvent (1.5 mL) and sample (0.1 g) consumption, ultra-high analytical throughput (6 min), and the ability to handle complex solid matrices. The idea of performing simultaneous analysis for multiple contaminants presented here fosters a more effective mode of operation in food control routines.

  1. The state of the art on the dry decontamination technologies applicable to highly radioactive contaminants and their needs for the national nuclear fuel cycle developent

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Won Zin; Lee, K.W.; Won, H.J.; Jung, C.H.; Chol, W.K.; Kim, G.N.; Moon, J.K

    2000-12-01

    This report is intended to establish their needs to support the dry decontamination activities applicable to highly radioactive contaminants based on the requirement of technologies development suggested from the national nuclear fuel cycle projects, such as DUPIC, advanced spent fuel management and long-lived radionuclides conversion. The technology needs associated with decontamination addressed the requirements associated with the efficiency of decontamination technology, the reduction of secondary wastes, applicabilities and the remote operation. And also, Characterization and decontamination technologies for various contaminants are reviewed and analysed. Based on the assessment, Unit dry decontamination processes are selected and the schematic flow diagram for decontamination of highly radioactive contaminants.

  2. Reduction of high levels of internal radio-contamination by dietary intervention in residents of areas affected by the Fukushima Daiichi nuclear plant disaster: a case series.

    Directory of Open Access Journals (Sweden)

    Masaharu Tsubokura

    Full Text Available Maintaining low levels of chronic internal contamination among residents in radiation-contaminated areas after a nuclear disaster is a great public health concern. However, the efficacy of reduction measures for individual internal contamination remains unknown. To reduce high levels of internal radiation exposure in a group of individuals exposed through environmental sources, we performed careful dietary intervention with identification of suspected contaminated foods, as part of mass voluntary radiation contamination screenings and counseling program in Minamisoma Municipal General Hospital and Hirata Central Hospital. From a total of 30,622 study participants, only 9 residents displayed internal cesium-137 (Cs-137 levels of more than 50 Bq/kg. The median level of internal Cs-137 contamination in these residents at the initial screening was 4,830 Bq/body (range: 2,130-15,918 Bq/body and 69.6 Bq/kg (range: 50.7-216.3 Bq/kg. All these residents with high levels of internal contamination consumed homegrown produce without radiation inspection, and often collected mushrooms in the wild or cultivated them on bed-logs in their homes. They were advised to consume distributed food mainly and to refrain from consuming potentially contaminated foods without radiation inspection and local produces under shipment restrictions such as mushrooms, mountain vegetables, and meat of wild life. A few months after the intervention, re-examination of Cs levels revealed remarkable reduction of internal contamination in all residents. Although the levels of internal radiation exposure appear to be minimal amongst most residents in Fukushima, a subset of the population, who unknowingly consumed highly contaminated foodstuffs, experienced high levels of internal contamination. There seem to be similarities in dietary preferences amongst residents with high internal contamination levels, and intervention based on pre- and post-test counseling and dietary advice from

  3. High-throughput preparation methods of crude extract for robust cell-free protein synthesis.

    Science.gov (United States)

    Kwon, Yong-Chan; Jewett, Michael C

    2015-03-02

    Crude extract based cell-free protein synthesis (CFPS) has emerged as a powerful technology platform for high-throughput protein production and genetic part characterization. Unfortunately, robust preparation of highly active extracts generally requires specialized and costly equipment and can be labor and time intensive. Moreover, cell lysis procedures can be hard to standardize, leading to different extract performance across laboratories. These challenges limit new entrants to the field and new applications, such as comprehensive genome engineering programs to improve extract performance. To address these challenges, we developed a generalizable and easily accessible high-throughput crude extract preparation method for CFPS based on sonication. To validate our approach, we investigated two Escherichia coli strains: BL21 Star™ (DE3) and a K12 MG1655 variant, achieving similar productivity (defined as CFPS yield in g/L) by varying only a few parameters. In addition, we observed identical productivity of cell extracts generated from culture volumes spanning three orders of magnitude (10 mL culture tubes to 10 L fermentation). We anticipate that our rapid and robust extract preparation method will speed-up screening of genomically engineered strains for CFPS applications, make possible highly active extracts from non-model organisms, and promote a more general use of CFPS in synthetic biology and biotechnology.

  4. An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions.

    Science.gov (United States)

    Ruan, Guihua; Wu, Zhenwei; Huang, Yipeng; Wei, Meiping; Su, Rihui; Du, Fuyou

    2016-04-22

    A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of Nα-benzoyl-l-arginine ethyl ester to Nα-benzoyl-l-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast and easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas.

  5. High-field 1H T1 and T2 NMR relaxation time measurements of H2O in homeopathic preparations of quartz, sulfur, and copper sulfate

    Science.gov (United States)

    Baumgartner, Stephan; Wolf, Martin; Skrabal, Peter; Bangerter, Felix; Heusser, Peter; Thurneysen, André; Wolf, Ursula

    2009-09-01

    Quantitative meta-analyses of randomized clinical trials investigating the specific therapeutic efficacy of homeopathic remedies yielded statistically significant differences compared to placebo. Since the remedies used contained mostly only very low concentrations of pharmacologically active compounds, these effects cannot be accounted for within the framework of current pharmacology. Theories to explain clinical effects of homeopathic remedies are partially based upon changes in diluent structure. To investigate the latter, we measured for the first time high-field (600/500 MHz) 1H T1 and T2 nuclear magnetic resonance relaxation times of H2O in homeopathic preparations with concurrent contamination control by inductively coupled plasma mass spectrometry (ICP-MS). Homeopathic preparations of quartz (10 c-30 c, n = 21, corresponding to iterative dilutions of 100-10-100-30), sulfur (13 x-30 x, n = 18, 10-13-10-30), and copper sulfate (11 c-30 c, n = 20, 100-11-100-30) were compared to n = 10 independent controls each (analogously agitated dilution medium) in randomized and blinded experiments. In none of the samples, the concentration of any element analyzed by ICP-MS exceeded 10 ppb. In the first measurement series (600 MHz), there was a significant increase in T1 for all samples as a function of time, and there were no significant differences between homeopathic potencies and controls. In the second measurement series (500 MHz) 1 year after preparation, we observed statistically significant increased T1 relaxation times for homeopathic sulfur preparations compared to controls. Fifteen out of 18 correlations between sample triplicates were higher for controls than for homeopathic preparations. No conclusive explanation for these phenomena can be given at present. Possible hypotheses involve differential leaching from the measurement vessel walls or a change in water molecule dynamics, i.e., in rotational correlation time and/or diffusion. Homeopathic preparations

  6. Decontamination Strategy for Large Area and/or Equipment Contaminated with Chemical and Biological Agents using a High Energy Arc Lamp (HEAL)

    Energy Technology Data Exchange (ETDEWEB)

    Schoske, Richard [ORNL; Kennedy, Patrick [ORNL; Duty, Chad E [ORNL; Smith, Rob R [ORNL; Huxford, Theodore J [ORNL; Bonavita, Angelo M [ORNL; Engleman, Greg [ORNL; Vass, Arpad Alexander [ORNL; Griest, Wayne H [ORNL; Ilgner, Ralph H [ORNL; Brown, Gilbert M [ORNL

    2009-04-01

    A strategy for the decontamination of large areas and or equipment contaminated with Biological Warfare Agents (BWAs) and Chemical Warfare Agents (CWAs) was demonstrated using a High Energy Arc Lamp (HEAL) photolysis system. This strategy offers an alternative that is potentially quicker, less hazardous, generates far less waste, and is easier to deploy than those currently fielded by the Department of Defense (DoD). For example, for large frame aircraft the United States Air Force still relies on the combination of weathering (stand alone in environment), air washing (fly aircraft) and finally washing the aircraft with Hot Soapy Water (HSW) in an attempt to remove any remaining contamination. This method is laborious, time consuming (upwards of 12+ hours not including decontamination site preparation), and requires large amounts of water (e.g., 1,600+ gallons for a single large frame aircraft), and generates large amounts of hazardous waste requiring disposal. The efficacy of the HEAL system was demonstrated using diisopropyl methyl phosphonate (DIMP) a G series CWA simulant, and Bacillus globigii (BG) a simulant of Bacillus anthracis. Experiments were designed to simulate the energy flux of a field deployable lamp system that could stand-off 17 meters from a 12m2 target area and uniformly expose a surface at 1360 W/m2. The HEAL system in the absence of a catalyst reduced the amount of B. globigii by five orders of magnitude at a starting concentration of 1.63 x 107 spores. In the case of CWA simulants, the HEAL system in the presence of the catalyst TiO2 effectively degraded DIMP sprayed onto a 100mm diameter Petri dish in 5 minutes.

  7. Preparing high-density polymer brushes by mechanically assisted polymer assembly (MAPA)

    Science.gov (United States)

    Wu, Tao; Efimenko, Kirill; Genzer, Jan

    2001-03-01

    We introduce a novel method of modifying the surface properties of materials. This technique, called MAPA (="mechanically assisted polymer assembly"), is based on: 1) chemically attaching polymerization initiators to the surface of an elastomeric network that has been previously stretched by a certain length, Δx, and 2) growing end-anchored macromolecules using surface initiated ("grafting from") atom transfer living radical polymerization. After the polymerization, the strain is removed from the substrate, which returns to its original size causing the grafted macromolecules to stretch away from the substrate and form a dense polymer brush. We demonstrate the feasibility of the MAPA method by preparing high-density polymer brushes of poly(acryl amide), PAAm. We show that, as expected, the grafting density of the PAAm brushes can be increased by increasing Δx. We demonstrate that polymer brushes with extremely high grafting densities can be successfully prepared by MAPA.

  8. Science Letters:Preparation of high-permeability NiCuZn ferrite

    Institute of Scientific and Technical Information of China (English)

    HU Jun; YAN Mi

    2005-01-01

    Appropriate addition of CuO/V2O5 and the reduction of the granularity of the raw materials particle decrease the sintering temperature ofNiZn ferrite from 1200 ℃ to 930 ℃. Furthermore, the magnetic properties of the NiZn ferrite prepared at low temperature of 930 ℃ is superior to that of the NiZn ferrite prepared by sintering at high temperature of 1200 ℃ because the microstructure of the NiZn ferrite sintered at 930 ℃ is more uniform and compact than that of the NiZn ferrite sintered at 1200 ℃.The high permeability of 1700 and relative loss coefficient tanδ//μi of 9.0×10-6 at 100 kHz was achieved in the (Ni0.17Zn0.63Cu0.20)Fe1.915O4 ferrite.

  9. Fe-Al2O3 nanocomposites prepared by high-energy ball milling

    DEFF Research Database (Denmark)

    Linderoth, Søren; Pedersen, M.S.

    1994-01-01

    Nanocomposites of alpha-Fe and alpha-Al2O3, prepared by high-energy ball milling, exhibit coercivities which are enhanced by about two orders of magnitude with respect to the bulk value. The degree of enhancement depends on the volume fraction (x(upsilon)) of Fe, with a maximum for x(upsilon) alm......Nanocomposites of alpha-Fe and alpha-Al2O3, prepared by high-energy ball milling, exhibit coercivities which are enhanced by about two orders of magnitude with respect to the bulk value. The degree of enhancement depends on the volume fraction (x(upsilon)) of Fe, with a maximum for x......(upsilon) almost-equal-to 0.25. The effect is ascribed to the production of single-domain magnetic grains. Mossbauer spectroscopy reveals the presence of iron oxide phases which could not be seen by x-ray and electron diffraction measurements....

  10. Reduction of Listeria innocua contamination in vacuum-packaged dry-cured Italian pork products after high hydrostatic pressure treatment

    Directory of Open Access Journals (Sweden)

    Giuseppe Merialdi

    2015-06-01

    Full Text Available The present work aims to present the results of the application of a treatment with high hydrostatic pressure (HHP on Italian fermented and dry-cured pork products. The products used in this study were portioned cured ham, portioned bacon and salami, vacuumpackaged and produced by a single processing company. Two studies were conducted on a single batch of the three products by means of an artificial contamination with Listeria innocua as a surrogate of L. monocytogenes. In the first trial a superficial contamination was obtained by immersion for 3 min in the culture broth with a concentration of approximately 9 log cfu/mL. At the end of the inoculum step, the pieces were dred at room temperature and vacuum packaged. In the second trial 50 kg of minced pork meat were contaminated before production of salami. In both cases the inoculum contained 5 strains of L. innocua. Subsequently, in both trials, 10 samples were randomly divided into two groups of 5 pieces each: i TH group, samples treated with HHP; ii group C, control samples, not subjected to any treatment. All samples were stored at refrigeration temperature at the end of HHP treatments (if applied, and analyzed for the determination of the surface (1st trial and deep (2nd trial quantitative contamination of L. innocua. pH and aW were also determined on 3 pieces of each products belonging to group C. The difference between the medians of the log cfu/cm2 or g established between controls and treated were compared using the non-parametric test (Kruskal-Wallis test with P<0.01. In all products and in both trials the level of contamination detected in treatment groups was always significantly lower than in controls (P<0.01. In particular, in vacuum-packaged ham, bacon and salami viability logarithmic viability reductions equal to -2.29, -2.54 and -2.51 were observed, respectively. This study aimed to evaluate a not-thermal treatment on Italian cured or fermented pork products. The results of

  11. Metagenomic analysis of the bioremediation of diesel-contaminated Canadian high arctic soils.

    Directory of Open Access Journals (Sweden)

    Etienne Yergeau

    Full Text Available As human activity in the Arctic increases, so does the risk of hydrocarbon pollution events. On site bioremediation of contaminated soil is the only feasible clean up solution in these remote areas, but degradation rates vary widely between bioremediation treatments. Most previous studies have focused on the feasibility of on site clean-up and very little attention has been given to the microbial and functional communities involved and their ecology. Here, we ask the question: which microorganisms and functional genes are abundant and active during hydrocarbon degradation at cold temperature? To answer this question, we sequenced the soil metagenome of an ongoing bioremediation project in Alert, Canada through a time course. We also used reverse-transcriptase real-time PCR (RT-qPCR to quantify the expression of several hydrocarbon-degrading genes. Pseudomonas species appeared as the most abundant organisms in Alert soils right after contamination with diesel and excavation (t = 0 and one month after the start of the bioremediation treatment (t = 1m, when degradation rates were at their highest, but decreased after one year (t = 1y, when residual soil hydrocarbons were almost depleted. This trend was also reflected in hydrocarbon degrading genes, which were mainly affiliated with Gammaproteobacteria at t = 0 and t = 1m and with Alphaproteobacteria and Actinobacteria at t = 1y. RT-qPCR assays confirmed that Pseudomonas and Rhodococcus species actively expressed hydrocarbon degradation genes in Arctic biopile soils. Taken together, these results indicated that biopile treatment leads to major shifts in soil microbial communities, favoring aerobic bacteria that can degrade hydrocarbons.

  12. Preparation, certification and interlaboratory analysis of workplace air filters spiked with high-fired beryllium oxide.

    Science.gov (United States)

    Oatts, Thomas J; Hicks, Cheryl E; Adams, Amy R; Brisson, Michael J; Youmans-McDonald, Linda D; Hoover, Mark D; Ashley, Kevin

    2012-02-01

    Occupational sampling and analysis for multiple elements is generally approached using various approved methods from authoritative government sources such as the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA), as well as consensus standards bodies such as ASTM International. The constituents of a sample can exist as unidentified compounds requiring sample preparation to be chosen appropriately, as in the case of beryllium in the form of beryllium oxide (BeO). An interlaboratory study was performed to collect analytical data from volunteer laboratories to examine the effectiveness of methods currently in use for preparation and analysis of samples containing calcined BeO powder. NIST SRM(®) 1877 high-fired BeO powder (1100 to 1200 °C calcining temperature; count median primary particle diameter 0.12 μm) was used to spike air filter media as a representative form of beryllium particulate matter present in workplace sampling that is known to be resistant to dissolution. The BeO powder standard reference material was gravimetrically prepared in a suspension and deposited onto 37 mm mixed cellulose ester air filters at five different levels between 0.5 μg and 25 μg of Be (as BeO). Sample sets consisting of five BeO-spiked filters (in duplicate) and two blank filters, for a total of twelve unique air filter samples per set, were submitted as blind samples to each of 27 participating laboratories. Participants were instructed to follow their current process for sample preparation and utilize their normal analytical methods for processing samples containing substances of this nature. Laboratories using more than one sample preparation and analysis method were provided with more than one sample set. Results from 34 data sets ultimately received from the 27 volunteer laboratories were subjected to applicable statistical analyses. The observed

  13. Distributed Mentoring: Preparing Preservice Resident Teachers for High Needs Urban High Schools

    Science.gov (United States)

    Leon, Marjorie Roth

    2014-01-01

    A distributed mentoring model was implemented to scaffold preservice teachers completing a residency in high needs urban turnaround high schools. In this situated learning context, expert faculty and peer mentors contributed confirmatory insights for promoting engaged evidence-based pedagogy, instructional differentiation, homework completion,…

  14. Preparation and characterization of highly photosensitive ZnO thin films

    Science.gov (United States)

    Jiménez González, Antonio E.; Nair, P. K.

    1996-07-01

    Highly photosensitive ZnO films were prepared by the chemical technique Successive Ion Layer Adsorption and Reaction (SILAR). The films posses high optical transmittance (>90%) in the VIS and IR ranges. The cristallinity, orientation of the crystallites and surface morphology undergo changes with annealing. The optical transmittance and reflectance measurements indicated changes in the position of the optical absorption edge: shifting from 353 nm to 366 nm when annealed at 450 °C for 2 hours. The films are highly photosensitive, offering photocurrent to dark current ratio of 105, in as prepared films under 900 Wm-2 illumination from a solar simulator. Annealing in oxygen, hydrogen and vacuum improved the dark conductivity and the photoconductivity of the films. This effect is related to the modification of the defect statistics of the films and involves cation interstitials and anion vacancies. The studies indicate that the ZnO films prepared by the SILAR process may be used, with appropriated postdeposition treatments, for specific applications.

  15. Fast high-throughput screening of temoporfin-loaded liposomal formulations prepared by ethanol injection method.

    Science.gov (United States)

    Yang, Kewei; Delaney, Joseph T; Schubert, Ulrich S; Fahr, Alfred

    2012-03-01

    A new strategy for fast, convenient high-throughput screening of liposomal formulations was developed, utilizing the automation of the so-called ethanol-injection method. This strategy was illustrated by the preparation and screening of the liposomal formulation library of a potent second-generation photosensitizer, temoporfin. Numerous liposomal formulations were efficiently prepared using a pipetting robot, followed by automated size characterization, using a dynamic light scattering plate reader. Incorporation efficiency of temoporfin and zeta potential were also detected in selected cases. To optimize the formulation, different parameters were investigated, including lipid types, lipid concentration in injected ethanol, ratio of ethanol to aqueous solution, ratio of drug to lipid, and the addition of functional phospholipid. Step-by-step small liposomes were prepared with high incorporation efficiency. At last, an optimized formulation was obtained for each lipid in the following condition: 36.4 mg·mL(-1) lipid, 13.1 mg·mL(-1) mPEG(2000)-DSPE, and 1:4 ethanol:buffer ratio. These liposomes were unilamellar spheres, with a diameter of approximately 50 nm, and were very stable for over 20 weeks. The results illustrate this approach to be promising for fast high-throughput screening of liposomal formulations.

  16. Lambda-Cyhalothrin Nanosuspension Prepared by the Melt Emulsification-High Pressure Homogenization Method

    Directory of Open Access Journals (Sweden)

    Zhenzhong Pan

    2015-01-01

    Full Text Available The nanosuspension of 5% lambda-cyhalothrin with 0.2% surfactants was prepared by the melt emulsification-high pressure homogenization method. The surfactants composition, content, and homogenization process were optimized. The anionic surfactant (1-dodecanesulfonic acid sodium salt and polymeric surfactant (maleic rosin-polyoxypropylene-polyoxyethylene ether sulfonate screened from 12 types of commercially common-used surfactants were used to prepare lambda-cyhalothrin nanosuspension with high dispersity and stability. The mean particle size and polydispersity index of the nanosuspension were 16.01 ± 0.11 nm and 0.266 ± 0.002, respectively. The high zeta potential value of −41.7 ± 1.3 mV and stable crystalline state of the nanoparticles indicated the excellent physical and chemical stability. The method could be widely used for preparing nanosuspension of various pesticides with melting points below boiling point of water. This formulation may avoid the use of organic solvents and reduce surfactants and is perspective for improving bioavailability and reducing residual pollution of pesticide in agricultural products and environment.

  17. Automation of Library Preparation for High-resolution ChIP-seq Profiling

    Science.gov (United States)

    Henry, Isabelle M.; Cotterman, Rebecca; Knoepfler, Paul; Comai, Luca; Kim, Ryan W.; O'Geen, Henriette

    2013-01-01

    The dynamic modification of DNA and histones plays a key role in transcriptional regulationthrough altering the packaging of DNA and modifying the nucleosome surface. These chromatin states, also referred to as the epigenome, are distinctive for different tissues, developmental stages, and disease states and can also be altered by environmental influences. New technologies allow the genome-wide visualization of the information encoded in theepigenome. For example, the chromatin immunoprecipitation (ChIP) assay allows investigators to characterize DNA–protein interactions in vivo. ChIP followed by high-throughput sequencing (ChIP-seq) is a powerful tool to identify genome-wide profiles of transcription factors, histone modifications, DNA methylation, and nucleosome positioning. The low yield of ChIP assays presents a challenge for reproducible and high quality library preparation for high throughput sequencing. Using the automated library preparation system from IntegenX, we prepared ChIP-seq libraries from as little as 1 ng ChIP DNA material. Sequencing of biological replicates on the Illumina platform confirmed a 95%-98% overlap of identified binding sites. Progress of ChIP experiments using limited tissue amounts from rice seedlings as well as other applications of the library automation system will be discussed.

  18. Preparation and characterization of a thermoresponsive gigaporous medium for high-speed protein chromatography.

    Science.gov (United States)

    Qu, Jian-Bo; Chen, Yan-Li; Huan, Guan-Sheng; Zhou, Wei-Qing; Liu, Jian-Guo; Zhu, Hu; Zhang, Xiao-Yun

    2015-01-01

    A high-speed thermoresponsive medium was developed by grafting poly(N-isopropylacrylamide-co-butyl methacrylate) (P(NIPAM-co-BMA)) brushes onto gigaporous polystyrene (PS) microspheres via surface-initiated atom transfer radical polymerization (ATRP) technique, which has strong mechanical strength, good chemical stability and high mass transfer rate for biomacromolecules. The gigaporous structure, surface chemical composition, static protein adsorption, and thermoresponsive chromatographic properties of prepared medium (PS-P(NIPAM-co-BMA)) were characterized in detail. Results showed that the PS microspheres were successfully grafted with P(NIPAM-co-BMA) brushes and that the gigaporous structure was robustly maintained. After grafting, the nonspecific adsorption of proteins on PS microspheres was greatly reduced. A column packed with PS-P(NIPAM-co-BMA) exhibited low backpressure and significant thermo-responsibility. By simply changing the column temperature, it was able to separate three model proteins at the mobile phase velocity up to 2167 cm h(-1). In conclusion, the thermoresponsive polymer brushes grafted gigaporous PS microspheres prepared by ATRP are very promising in 'green' high-speed preparative protein chromatography.

  19. Development of a high vacuum sample preparation system for helium mass spectrometer

    Science.gov (United States)

    Kumar, P.; Das, N. K.; Mallik, C.; Bhandari, R. K.

    2012-11-01

    A high vacuum sample preparation system for the 3He/4He ratio mass spectrometer (Helix SFT) has been developed to remove all the gaseous constituents excluding helium from the field gases. The sample preparation system comprises of turbo molecular pump, ion pump, zirconium getter, pipettes and vacuum gauges with controller. All these are fitted with cylindrical SS chamber using all metal valves. The field samples are initially treated with activated charcoal trap immersed in liquid nitrogen to cutoff major impurities and moisture present in the sample gas. A sample of 5 ml is collected out of this stage at a pressure of 10-2 mbar. This sample is subsequently purified at a reduced pressure of 10-7 mbar before it is injected into the ion source of the mass spectrometer. The sample pressure was maintained below 10-7 mbar with turbo molecular vacuum pumps and ion pumps. The sample gas passes through several getter elements and a cold finger with the help of manual high vacuum valves before it is fed to the mass spectrometer. Thus the high vacuum sample preparation system introduces completely clean, dry and refined helium sample to the mass spectrometer for best possible analysis of isotopic ratio of helium.

  20. Preparative separation of cacao bean procyanidins by high-speed counter-current chromatography.

    Science.gov (United States)

    Li, Lingxi; Zhang, Shuting; Cui, Yan; Li, Yuanyuan; Luo, Lanxin; Zhou, Peiyu; Sun, Baoshan

    2016-11-15

    In this work, an efficient method for preparative separation of procyanidins from raw cacao bean extract by high-speed counter-current chromatography (HSCCC) was developed. Under the optimized solvent system of n-hexane-ethyl acetate-water (1:50:50, v/v/v) with a combination of head-tail and tail-head elution modes, various procyanidins fractions with different polymerization degrees were successfully separated. UPLC, QTOF-MS and (1)H NMR analysis verified that these fractions contained monomer up to pentamer respectively. Dimeric procyanidin B2 (purity>86%) could be isolated by HSCCC in a single run. Other individual procyanidins in these fractions could be further isolated and purified by preparative HPLC. The developed HSCCC together with preparative HPLC techniques appeared to be a useful tool for large preparation of different procyanidins from cacao beans. Furthermore, by antioxidant activity assays, it was proved that both fractions and individual procyanidins possessed greater antioxidant activities compared to standard trolox. The antioxidant activities of procyanidins increase as the increase of their polymerization degree. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Assessment of fly ash-aided phytostabilisation of highly contaminated soils after an 8-year field trial

    Energy Technology Data Exchange (ETDEWEB)

    Pourrut, Bertrand [Universite Lille Nord de France, Lille (France); Groupe ISA, Equipe Sols et Environnement, Laboratoire Genie Civil et geoEnvironnement (LGCgE) Lille Nord de France EA 4515, 48 boulevard Vauban, 59046 Lille Cedex (France); Lopareva-Pohu, Alena [Universite Lille Nord de France, Lille (France); Groupe ISA, Equipe Sols et Environnement, Laboratoire Genie Civil et geoEnvironnement (LGCgE) Lille Nord de France EA 4515, 48 boulevard Vauban, 59046 Lille Cedex (France); Universite du Littoral-Cote d' Opale, Unite de Chimie Environnementale et Interaction sur le Vivant (UCEIV), EA 4492, Maison de la Recherche en Environnement Industriel de Dunkerque 2, avenue Maurice Schumann, 59140 Dunkerque (France); Pruvot, Christelle [Universite Lille Nord de France, Lille (France); Groupe ISA, Equipe Sols et Environnement, Laboratoire Genie Civil et geoEnvironnement (LGCgE) Lille Nord de France EA 4515, 48 boulevard Vauban, 59046 Lille Cedex (France); Garcon, Guillaume; Verdin, Anthony [Universite Lille Nord de France, Lille (France); Universite du Littoral-Cote d' Opale, Unite de Chimie Environnementale et Interaction sur le Vivant (UCEIV), EA 4492, Maison de la Recherche en Environnement Industriel de Dunkerque 2, avenue Maurice Schumann, 59140 Dunkerque (France); Waterlot, Christophe; Bidar, Geraldine [Universite Lille Nord de France, Lille (France); Groupe ISA, Equipe Sols et Environnement, Laboratoire Genie Civil et geoEnvironnement (LGCgE) Lille Nord de France EA 4515, 48 boulevard Vauban, 59046 Lille Cedex (France); Shirali, Pirouz [Universite Lille Nord de France, Lille (France); Universite du Littoral-Cote d' Opale, Unite de Chimie Environnementale et Interaction sur le Vivant (UCEIV), EA 4492, Maison de la Recherche en Environnement Industriel de Dunkerque 2, avenue Maurice Schumann, 59140 Dunkerque (France); and others

    2011-10-01

    Aided phytostabilisation is a cost-efficient technique to manage metal-contaminated areas, particularly in the presence of extensive pollution. Plant establishment and survival in highly metal-contaminated soils are crucial for phytostabilisation success, as metal toxicity for plants is widely reported. A relevant phytostabilisation solution must limit metal transfer through the food chain. Therefore, this study aimed at evaluating the long-term efficiency of aided phytostabilisation on former agricultural soils highly contaminated by cadmium, lead, and zinc. The influence of afforestation and fly ash amendments on reducing metal phytoavailability was investigated as were their effects on plant development. Before being planted with a tree mix, the site was divided into three plots: a reference plot with no amendment, a plot amended with silico-aluminous fly ash and one with sulfo-calcic fly ash. Unlike Salix alba and Quercus robur, Alnus glutinosa, Acer pseudoplatanus and Robinia pseudoacacia grew well on the site and accumulated, overall, quite low concentrations of metals in their leaves and young twigs. This suggests that these three species have an excluder phenotype for Cd, Zn and Pb. After 8 years, metal availability to A. glutinosa, A. pseudoplatanus and R. pseudoacacia, and translocation to their above-ground parts, strongly decreased in fly ash-amended soils. Such decreases fit well together with the depletion of CaCl{sub 2}-extractable metals in amended soils. Although both fly ashes were effective to decrease Cd, Pb and Zn concentrations in above-ground parts of trees, the sulfo-calcic ash was more efficient.

  2. Gender Differences in Introductory University Physics Performance: The Influence of High School Physics Preparation and Affect

    Science.gov (United States)

    Hazari, Zahra

    2006-12-01

    The attrition of females studying physics after high school has been a continuing concern for the physics education community. If females are well prepared, feel confident, and do well in introductory college physics, they may be inclined to study physics further. This quantitative study uses HLM to identify factors from high school physics preparation (content, pedagogy, and assessment) and the affective domain that predict female and male performance in introductory college physics. The study includes controls for student demographic and academic background characteristics, and the final dataset consists of 1973 surveys from 54 introductory college physics classes. The results highlight high school physics and affective experiences that differentially predict female and male performance. These experiences include: learning requirements, computer graphing/analysis, long written problems, everyday world examples, community projects cumulative tests/quizzes, father's encouragement, family's belief that science leads to a better career, and the length of time students believe that high school physics would help in university physics. There were also experiences that similarly predict female and male performance. The results paint a dynamic picture of the factors from high school physics and the affective domain that influence the future physics performance of females and males. The implication is that there are many aspects to the teaching of physics in high school that, although widely used and thought to be effective, need reform in their implementation in order to be fully beneficial to females and/or males in college.

  3. Preparation and characterization of coatings with a high reflectivity on planar substrates and inside silica tubes

    Science.gov (United States)

    Bartoň, Ivo; Matějec, Vlastimil; Mrázek, Jan; Podrazký, Ondřej

    2015-01-01

    The paper presents results on preparation and characterization of highly reflective coatings on planar substrates and inside silica tubes. Coatings are designed for a maximum reflectivity at a wavelength of 550 nm and consist of several pairs of oxide layers. Each pair is composed of one layer with a high refractive index and one layer with a low refractive index with a refractive-index contrast of about 1.1. The layers were prepared by the sol-gel method. High-index layers were applied from a sol based on titanium butoxide while a sol of tetramethoxysilane was use for low-index layers. The sols were deposited onto silica slides or onto walls of silica tubes by using the dip-coating technique. Applied gel layers were thermally treated at temperatures up to 450 °C in order to obtain densified layers with thicknesses 50-100 nm. Coatings with one to five pairs of layers were fabricated. Prepared coatings were characterized by transmission and reflection spectrometry in a wavelength range from 190 to- 1100 nm, by contact profilometry, and by spectral ellipsometry. Thicknesses and refractive indices of coatings were determined from these measurements. For normal light incidence a reflectivity higher than 99% in a wavelength range of 500-650 nm was measured by transmission spectrometry on coatings prepared from four or five pairs of layers. Similar reflectivity values were determined for angles of incidence of 15, 30, 45 and 60 degrees by using reflection spectrometry. Transmission spectra measured on the coated tubes which show interference bands are also presented in the paper.

  4. Bacterial Diversity and Bioremediation Potential of the Highly Contaminated Marine Sediments at El-Max District (Egypt, Mediterranean Sea).

    Science.gov (United States)

    Amer, Ranya A; Mapelli, Francesca; El Gendi, Hamada M; Barbato, Marta; Goda, Doaa A; Corsini, Anna; Cavalca, Lucia; Fusi, Marco; Borin, Sara; Daffonchio, Daniele; Abdel-Fattah, Yasser R

    2015-01-01

    Coastal environments worldwide are threatened by the effects of pollution, a risk particularly high in semienclosed basins like the Mediterranean Sea that is poorly studied from bioremediation potential perspective especially in the Southern coast. Here, we investigated the physical, chemical, and microbiological features of hydrocarbon and heavy metals contaminated sediments collected at El-Max bay (Egypt). Molecular and statistical approaches assessing the structure of the sediment-dwelling bacterial communities showed correlations between the composition of bacterial assemblages and the associated environmental parameters. Fifty strains were isolated on mineral media supplemented by 1% crude oil and identified as a diverse range of hydrocarbon-degrading bacteria involved in different successional stages of biodegradation. We screened the collection for biotechnological potential studying biosurfactant production, biofilm formation, and the capability to utilize different hydrocarbons. Some strains were able to grow on multiple hydrocarbons as unique carbon source and presented biosurfactant-like activities and/or capacity to form biofilm and owned genes involved in different detoxification/degradation processes. El-Max sediments represent a promising reservoir of novel bacterial strains adapted to high hydrocarbon contamination loads. The potential of the strains for exploitation for in situ intervention to combat pollution in coastal areas is discussed.

  5. High-throughput metagenomic analysis of petroleum-contaminated soil microbiome reveals the versatility in xenobiotic aromatics metabolism.

    Science.gov (United States)

    Bao, Yun-Juan; Xu, Zixiang; Li, Yang; Yao, Zhi; Sun, Jibin; Song, Hui

    2017-06-01

    The soil with petroleum contamination is one of the most studied soil ecosystems due to its rich microorganisms for hydrocarbon degradation and broad applications in bioremediation. However, our understanding of the genomic properties and functional traits of the soil microbiome is limited. In this study, we used high-throughput metagenomic sequencing to comprehensively study the microbial community from petroleum-contaminated soils near Tianjin Dagang oilfield in eastern China. The analysis reveals that the soil metagenome is characterized by high level of community diversity and metabolic versatility. The metageome community is predominated by γ-Proteobacteria and α-Proteobacteria, which are key players for petroleum hydrocarbon degradation. The functional study demonstrates over-represented enzyme groups and pathways involved in degradation of a broad set of xenobiotic aromatic compounds, including toluene, xylene, chlorobenzoate, aminobenzoate, DDT, methylnaphthalene, and bisphenol. A composite metabolic network is proposed for the identified pathways, thus consolidating our identification of the pathways. The overall data demonstrated the great potential of the studied soil microbiome in the xenobiotic aromatics degradation. The results not only establish a rich reservoir for novel enzyme discovery but also provide putative applications in bioremediation. Copyright © 2016. Published by Elsevier B.V.

  6. Bacterial Diversity and Bioremediation Potential of the Highly Contaminated Marine Sediments at El-Max District (Egypt, Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Ranya A. Amer

    2015-01-01

    Full Text Available Coastal environments worldwide are threatened by the effects of pollution, a risk particularly high in semienclosed basins like the Mediterranean Sea that is poorly studied from bioremediation potential perspective especially in the Southern coast. Here, we investigated the physical, chemical, and microbiological features of hydrocarbon and heavy metals contaminated sediments collected at El-Max bay (Egypt. Molecular and statistical approaches assessing the structure of the sediment-dwelling bacterial communities showed correlations between the composition of bacterial assemblages and the associated environmental parameters. Fifty strains were isolated on mineral media supplemented by 1% crude oil and identified as a diverse range of hydrocarbon-degrading bacteria involved in different successional stages of biodegradation. We screened the collection for biotechnological potential studying biosurfactant production, biofilm formation, and the capability to utilize different hydrocarbons. Some strains were able to grow on multiple hydrocarbons as unique carbon source and presented biosurfactant-like activities and/or capacity to form biofilm and owned genes involved in different detoxification/degradation processes. El-Max sediments represent a promising reservoir of novel bacterial strains adapted to high hydrocarbon contamination loads. The potential of the strains for exploitation for in situ intervention to combat pollution in coastal areas is discussed.

  7. Bacterial Diversity and Bioremediation Potential of the Highly Contaminated Marine Sediments at El-Max District (Egypt, Mediterranean Sea)

    KAUST Repository

    Amer, Ranya A.

    2015-02-01

    Coastal environments worldwide are threatened by the effects of pollution, a risk particularly high in semienclosed basins like the Mediterranean Sea that is poorly studied from bioremediation potential perspective especially in the Southern coast. Here, we investigated the physical, chemical, and microbiological features of hydrocarbon and heavy metals contaminated sediments collected at El-Max bay (Egypt). Molecular and statistical approaches assessing the structure of the sediment-dwelling bacterial communities showed correlations between the composition of bacterial assemblages and the associated environmental parameters. Fifty strains were isolated on mineral media supplemented by 1% crude oil and identified as a diverse range of hydrocarbon-degrading bacteria involved in different successional stages of biodegradation. We screened the collection for biotechnological potential studying biosurfactant production, biofilm formation, and the capability to utilize different hydrocarbons. Some strains were able to grow on multiple hydrocarbons as unique carbon source and presented biosurfactant-like activities and/or capacity to form biofilm and owned genes involved in different detoxification/degradation processes. El-Max sediments represent a promising reservoir of novel bacterial strains adapted to high hydrocarbon contamination loads. The potential of the strains for exploitation for in situ intervention to combat pollution in coastal areas is discussed.

  8. Studies on preparation and property of high-substitutional starch acetate hydrophode for the membrane material

    Institute of Scientific and Technical Information of China (English)

    ZUO Xiu-jin; DAI Xiao-min; MA Xiao-jun

    2005-01-01

    @@ Control-release technique is probably the most widely used,films control-release technique is the key of control-release technique,and film materials are the elements.The high-substitutional starch acetate was prepared by acetylation of starch with an acetic anhydride mixture.The best parameter of the technics (time of activation and reaction, reactant ratio) was obtained by orthogonal experiments.It was the hydrophode membrane material that property of the high-substitutional starch acetate was proofed.

  9. Preparation of high-performance optical coatings with fluoride nanoparticle films made from autoclaved sols.

    Science.gov (United States)

    Murata, Tsuyoshi; Ishizawa, Hitoshi; Motoyama, Izumi; Tanaka, Akira

    2006-03-01

    An ultralow refractive index is very advantageous when one designs antireflective coatings. We successfully obtained high-quality MgF2 thin films with ultralow refractive indices from autoclaved sols prepared from magnesium acetate and hydrofluoric acid. The MgF2 films consist of nanosized particles, and they have high laser-exposure durability at 193 nm. The reflectance of the antireflective coating with five layers, of which the top layer is formed by our method, is lower than 0.6% in the incident angle range of 0 degrees - 60 degrees at 193 nm.

  10. 四种石油污染土壤生物修复技术研究%Bioremediation on 4 Soils Contaminated by Petroleum Oils Using Prepared Bed Processes

    Institute of Scientific and Technical Information of China (English)

    张海荣; 李培军; 孙铁珩; 姜昌亮; 许华夏; 张春桂; 马学军; 姚德明

    2001-01-01

    In this investigation, the soils contaminated by crude oil fromLiaohe Oil Field were treated using prepared bed bioremediation technology. The results showed that degrading rate of TPHs were reached 38%—60% after 84 days treatment, when the concentrations of total petroleum hydrocarbons (TPHs) in soils were in a range of 25.8 g·kg-1 —77.2 g·kg-1. It was found that the composition of the oils greatly affected the degradation rate, having a degradation order of different oils as pollutants in soils with: thin oil > high condensed oil > thick oil > extremely thick oil. It has been indicated that the bioremediation of soil contaminated by oil is a practical technology.%在实验室小试和现场中试的基础上,采用预制床处理工艺对辽河油田4种不同类型石油污染土壤进行实用规模的生物处理技术研究。工程运行结果表明,当稀油、稠油、特稠油和高凝油污染土壤中石油烃总量(TPH)为25.8—77.2g.kg-1时,经过84d的运行,TPH去除率为38%—60%。TPH的降解速率除与微生物的生长环境有关外还与石油的理化性质密切相关。4种油污染土壤的降解速率依次为:稀油>高凝油>稠油>特稠油,TPH的组分对其降解速率有重要影响。本研究为大规模石油污染土壤异位生物修复提供了技术支持

  11. Low-volume plus ascorbic acid vs high-volume plus simethicone bowel preparation before colonoscopy

    Institute of Scientific and Technical Information of China (English)

    Stefano Pontone; Rita Angelini; Monica Standoli; Gregorio Patrizi; Franco Culasso; Paolo Pontone; Adriano Redler

    2011-01-01

    AIM: To investigate the effectiveness of low-volume plus ascorbic acid [polyethylene glycol plus ascorbic acid (PEG + Asc)] and high-volume plus simethicone [polyethylene glycol plus simethicone (PEG + Sim)] bowel preparations.METHODS: A total of one hundred and forty-four outpatients (76 males), aged from 20 to 84 years (me dian age 59.5 years), who attended our Department, were divided into two groups, age and sex matched, and underwent colonoscopy. Two questionnaires, one for patients reporting acceptability and the other for endoscopists evaluating bowel cleansing effectiveness according to validated scales, were completed. Indica tions, timing of examination and endoscopical findings were recorded. Biopsy forceps were used as a measur ing tool in order to determine polyp endoscopic sizeestimation. Difficulty in completing the preparation was rated in a 5-point Likert scale (1 = easy to 5 = un able). Adverse experiences (fullness, cramps, nausea, vomiting, abdominal pain, headache and insomnia), number of evacuations and types of activities per formed during preparation (walking or resting in bed) were also investigated.RESULTS: Seventy-two patients were selected for each group. The two groups were age and sex matched as well as being comparable in terms of medical history and drug therapies taken. Fourteen patients dropped out from the trial because they did not complete the preparation procedure. Ratings of global bowel cleans ing examinations were considered to be adequate in 91% of PEG + Asc and 88% of PEG + Sim patients. Residual Stool Score indicated similar levels of amount and consistency of residual stool; there was a signifi cant difference in the percentage of bowel wall visuali zation in favour of PEG + Sim patients. In the PEG + Sim group, 12 adenomas < 10 mm diameter (5/left co lon + 7/right colon) vs 9 (8/left colon + 1/right colon) in the PEG + Asc group were diagnosed. Visualization of small lesions seems to be one of the primary advan tages of

  12. Measuring fuel contamination using high speed gas chromotography and cone penetration techniques

    Energy Technology Data Exchange (ETDEWEB)

    Farrington, S.P.; Bratton, W.L.; Akard, M.L.; Klemp, M.

    1995-12-31

    Decision processes during characterization and cleanup of hazardous waste sites are greatly retarded by the turnaround time and expense incurred through the use of conventional sampling and laboratory analyses. Furthermore, conventional soil and groundwater sampling procedures present many opportunities for loss of volatile organic compounds (VOC) by exposing sample media to the atmosphere during transfers between and among sampling devices and containers. While on-site analysis by conventional gas chromatography (GC) can reduce analytical turnaround time, time-consuming sample preparation procedures are still often required, and the potential for loss of VOC is not reduced.

  13. Characteristics of cinnamaldehyde nanoemulsion prepared using APV-high pressure homogenizer and ultra turrax

    Science.gov (United States)

    Asmawati, Mustapha, Wan Aida Wan; Yusop, Salma Mohamad; Maskat, Mohamad Yusof; Shamsuddin, Ahmad Fuad

    2014-09-01

    This work aims at determining the optimized parameter to prepare cinnamaldehyde nanoemulsion by using high pressure homogenizer (2 passes at 900 bar) and ultra turrax T25 (12000 rpm for 5 min). Thirteen formulation of cinnamaldehyde nanoemulsion obtained by Design Expert software were prepared at a range of oil and surfactant concentration between of 5% and 10% (v/v). Commercial cinnamaldehyde was blended with deionized water and Tween 80 (emulsifier). The responses used in obtaining the optimized condition were droplet size, polydispersity index (PDI) and emulsion stability (ζ-potential). Result showed that nanoemulsion prepared using 5% (v/v) cinnamaldehyde and 5% (v/v) Tween 80 and homogenized using high pressure homogenizer (APV, Germany) has the smallest size of droplet. The response surface plots for droplet size showed that droplet size (diameter, nm) decreased as the concentration of cinnamaldehyde oil and Tween 80 decreased. However ζ-potential value (mV) showed an increment as the cinnamaldehyde oil concentration decreased and Tween 80 increased. The optimum formulation as predicted by response surface methodology in order to produce a stable cinnamaldehyde nanoemulsion was at 5% cinnamaldehyde oil and 7.11% Tween 80. At this optimized conditions the droplet size and ζ-potential values were 56.56 nm and -4.32 mV, respectively.

  14. Semi-Automated Library Preparation for High-Throughput DNA Sequencing Platforms

    Directory of Open Access Journals (Sweden)

    Eveline Farias-Hesson

    2010-01-01

    Full Text Available Next-generation sequencing platforms are powerful technologies, providing gigabases of genetic information in a single run. An important prerequisite for high-throughput DNA sequencing is the development of robust and cost-effective preprocessing protocols for DNA sample library construction. Here we report the development of a semi-automated sample preparation protocol to produce adaptor-ligated fragment libraries. Using a liquid-handling robot in conjunction with Carboxy Terminated Magnetic Beads, we labeled each library sample using a unique 6 bp DNA barcode, which allowed multiplex sample processing and sequencing of 32 libraries in a single run using Applied Biosystems' SOLiD sequencer. We applied our semi-automated pipeline to targeted medical resequencing of nuclear candidate genes in individuals affected by mitochondrial disorders. This novel method is capable of preparing as much as 32 DNA libraries in 2.01 days (8-hour workday for emulsion PCR/high throughput DNA sequencing, increasing sample preparation production by 8-fold.

  15. Preparative and structural extension of oxoborate chemistry through high-pressure/high-temperature syntheses

    Energy Technology Data Exchange (ETDEWEB)

    Huppertz, Hubert; Emme, Holger [Department Chemie, Ludwig-Maximilians-Universitaet Muenchen, Butenandtstrasse 5-13 (Haus D), D-81377 Munich (Germany)

    2004-04-14

    High-pressure/high-temperature conditions were used to synthesize the new rare earth oxoborates Ln{sub 4}B{sub 6}O{sub 15} (Ln = Dy, Ho; 8.0 GPa, 1000 deg. C) and {alpha}-Ln{sub 2}B{sub 4}O{sub 9} (Ln = Eu, Gd, Tb, Dy; 10.0 GPa, 1150 deg. C) in a Walker-type multianvil apparatus. In addition to their new compositions, which were unattainable under normal pressure conditions, the structures exhibit the new structural motif of edge sharing BO{sub 4} tetrahedra leading to a structural extension of oxoborate chemistry.

  16. An Efficient Protocol for Preparation of Gallic Acid from Terminalia bellirica (Gaertn.) Roxb by Combination of Macroporous Resin and Preparative High-Performance Liquid Chromatography.

    Science.gov (United States)

    Zou, Denglang; Chen, Tao; Chen, Chen; Li, Hongmei; Liu, Yongling; Li, Yulin

    2016-08-01

    In this article, macroporous resin column chromatography and preparative high-performance liquid chromatography were applied for preparation of gallic acid from Terminalia bellirica (Gaertn.) Roxb. In the first step, six kinds of resins were investigated by adsorption and desorption tests and AB-8 macroporous resin was selected for the enrichment of gallic acid. As a result, 20 g of gallic acid at a purity of 71% could be separated from 100 g of crude extract in which the content of gallic acid was 16.7% and the recovery of gallic acid reached 85.0%. In the second step, preparative high-performance liquid chromatography was selected to purify gallic acid. As a result, 640 mg of gallic acid at a purity of 99.1% was obtained from 1 g of sample in 35 min. The results demonstrated that macroporous resin coupled with preparative high-performance liquid chromatography was suitable for preparation of gallic acid from T. bellirica (Gaertn.) Roxb.

  17. Effect of additives on the properties of polyaniline nanofibers prepared by high gravity chemical oxidative polymerization.

    Science.gov (United States)

    Zhao, Yibo; Arowo, Moses; Wu, Wei; Chen, Jianfeng

    2015-05-12

    Polyaniline (PANI) nanofibers with improved properties were prepared by high gravity chemical oxidative polymerization in a rotating packed bed with the assistance of p-aminodiphenylamine (AD) and p-phenylenediamine (AP). The effects of reactor type, additive dosage, reaction temperature, and high-gravity level on the properties of products were investigated in detail. Three conclusions were made: (1) a small amount of additive can significantly improve some properties of the nanofibers such as uniformity, specific surface area, and specific capacitance; (2) in order to obtain high-quality nanofibers, the high-gravity level should coordinate with the reaction rate; (3) the molecular weight and conductivity of PANI decrease with the increase of additive dosage. The products have larger specific surface areas of up to 73.9 and 68.4 m(2)/g and consequently improved specific capacitance of up to 527.5 and 552 F/g for the PANI nanofibers prepared with AD and AP, respectively. However, the specific surface area and specific capacitance of pure PANI are only 49.1 m(2)/g and 333.3 F/g, respectively. This research provides a simple, reliable, and scalable method to produce PANI nanofibers of high performances.

  18. Ochratoxin A Contamination of Red Chili Peppers from Chile, Bolivia and Peru, Countries with a High Incidence of Gallbladder Cancer.

    Science.gov (United States)

    Ikoma, Toshikazu; Tsuchiya, Yasuo; Asai, Takao; Okano, Kiyoshi; Ito, Naoko; Endoh, Kazuo; Yamamoto, Masaharu; Nakamura, Kazutoshi

    2015-01-01

    Our previous study detected aflatoxins in red chili peppers from Chile, Bolivia, and Peru, each of which have a high incidence of gallbladder cancer (GBC). Since the aflatoxin B1 concentration was not so high in these peppers, it is important to clarify the presence of other mycotoxins. Here we attempted to determine any associations between the concentrations of aflatoxins and ochratoxin A (OTA) in red chili peppers, and the corresponding GBC incidences. We collected red chili peppers from three areas in Peru: Trujillo (a high GBC incidence area), Cusco (an intermediate GBC incidence area), and Lima (a low GBC incidence rate), and from Chile and Bolivia. Aflatoxins and OTA were extracted with organic solvents. The concentrations of aflatoxins B1, B2, G1, and G2, and OTA were measured by high-performance liquid chromatography. The values obtained were compared with the incidence of GBC in each area or country. All of the red chili peppers from the three areas showed contamination with aflatoxins below the Commission of the European Communities (EC) recommended limits (5 μg/kg), but the OTA contamination of two samples was above the EC recommended limit (15 μg/kg). The mean concentrations of OTA in the peppers from Chile (mean 355 μg/kg, range Bolivia (mean 207 μg/kg, range 0.8-628 μg/kg), which has a high incidence of GBC, were higher than that in Peru (14 μg/kg, range Bolivia, and Peru was stronger than that of aflatoxins. Our data suggest that OTA in red chili peppers may be associated with the development of GBC.

  19. Cadmium accumulation characteristics and removal potentials of high cadmium accumulating rice line grown in cadmium-contaminated soils.

    Science.gov (United States)

    Tang, Hao; Li, Tingxuan; Yu, Haiying; Zhang, Xizhou

    2016-08-01

    Phytoextraction is a promising technique to remove cadmium (Cd) from contaminated soils. In this research, the two different Cd accumulation rice lines of Lu527-8 (the high Cd accumulating rice line) and Lu527-4 (the normal rice line) were grown in soils with different Cd treatments (0, 5, 10, and 20 mg kg(-1) soil) to evaluate Cd accumulation characteristics and Cd removal potentials. When the concentration of Cd in soil increased, Lu527-8 showed less symptoms of phytotoxicity when compared to Lu527-4. Furthermore, Lu527-8 demonstrated greater shoot Cd accumulation (321.17-964.95 mg plant(-1)) than Lu527-4 (50.37-201.66 μg plant(-1)) at the jointing and filling stages. The soil available Cd content of Lu527-8 significantly decreased by 26.92-38.97 and 27.77-63.44 % at the jointing and filling stages, respectively. Meanwhile, the total Cd content in soil also reduced by 11.64-46.75 and 21.41-54.11 % at jointing and filling stages, respectively. When the Cd concentration in soil was 20 mg kg(-1), the Cd extraction rate in shoots of Lu527-8 reached 2.12 and 2.85 % which increased 10.60 and 6.48 times compared with that of Lu527-4 at the jointing and filling stages, respectively. In conclusion, this study demonstrates that Lu527-8 shows great abilities of Cd accumulation and Cd removal potential from contaminated soils with different Cd treatments and it is a promising species for phytoextraction of Cd-contaminated soils.

  20. Method of Preparation for High-Purity Nanocrystalline Anhydrous Cesium Perrhenate

    Directory of Open Access Journals (Sweden)

    Katarzyna Leszczyńska-Sejda

    2017-03-01

    Full Text Available This paper is devoted to the preparation of high-purity anhydrous nanocrystalline cesium perrhenate, which is applied in catalyst preparation. It was found that anhydrous cesium perrhenate with a crystal size <45 nm can be obtained using cesium ion sorption and elution using aqueous solutions of perrhenic acid with subsequent crystallisation, purification, and drying. The following composition of the as-obtained product was reported: 34.7% Cs; 48.6% Re and <2 ppm Bi; <3 ppm Zn; <2 ppm As; <10 ppm Ni; < 3 ppm Mg; <5 ppm Cu; <5 ppm Mo; <5 ppm Pb; <10 ppm K; <2 ppm Na; <5 ppm Ca; <3 ppm Fe.

  1. Preparation, characterization, and high performance of RuSe/C for direct methanol fuel cells

    Science.gov (United States)

    Serov, Alexey Alexandrovich; Min, Myoungki; Chai, Geunseok; Han, Sangil; Kang, Soonki; Kwak, Chan

    RuSe/C catalysts prepared by different methods have been tested for oxygen reduction and the results analyzed based on the active species and particle size distribution. Inorganic precursor methods exhibit higher catalytic performance than the carbonyl method. Selenious acid is an excellent inorganic precursor. X-ray photoelectron spectra indicate that selenium in a high oxidation state is more active than that with zero valence. The effect of operating conditions is analyzed for catalysts prepared by the inorganic precursor method. The optimum heat-treatment temperature for both active phase formation and particle size distribution is 300 °C. A performance of 62 mW cm -2 at 80 °C is obtained using 80 wt.% RuSe/C in the cathode.

  2. Preparation of Highly Squeezed States and Multi-component Entangled Coherent States via the Raman Interaction

    Institute of Scientific and Technical Information of China (English)

    ZHENG Sbi-Biao

    2002-01-01

    A method is presented for generating highly squeezed states of a cavity field via the atom-cavity field interaction of the Raman type. In the scheme a sequence of three-level A-type atoms interacts with a cavity field, displaced by a classical source, in a Rarman manner. Then the atomic states are measured. By this way the cavity field may collapse onto a superposition of several coherent states, which exhibits strong squeezing. The scheme can also be used to prepare superpositions of many two-mode coherent states for two cavity fields. The coherent states in each mode are on a straight line. This is the first way for preparing multi-component entangled coherent states of this type in cavity QED.

  3. Evaluation of phosphate fertilizers for the stabilization of cadmium in highly contaminated soils.

    Science.gov (United States)

    Thawornchaisit, Usarat; Polprasert, Chongrak

    2009-06-15

    The efficiency of three phosphate fertilizers including triple superphosphate (TSP), diammonium phosphate (DAP), and phosphate rock (PR) as stabilizing agents of cadmium-contaminated soils has been assessed in this study. Two types of assessment criteria, (a) the reduction of leachable cadmium concentration; and (b) the changes in Cd association with specific operational soil fraction based on the sequential extraction data, are used in the evaluation of stabilization performance of each fertilizer. Results of the study showed that after the 60-day stabilization, the leachable concentrations of Cd in PR-, DAP- and TSP- treated soils reduced from 306 mg/kg (the control) to 140, 34, and 12 mg/kg with the stabilization efficiency as TSP>DAP>PR. Results from the assessment of Cd speciation via sequential extraction procedure revealed that the soluble-exchangeable fraction and the surface adsorption fraction of Cd in the soils treated with PO(4) fertilizers, especially with TSP, have been reduced considerably. In addition, it is found that the reduction was correspondingly related with the increase of more stable forms of cadmium: the metal bound to manganese oxides and the metal bound to crystalline iron oxides. Treatment efficiency increased as the phosphate dose (based on the molar ratio of PO(4)/Cd) increased. In addition, it was observed that stabilization was most effective when using the molar ratio of PO(4)/Cd at 2:1 and at least 21-day and 28-day stabilization time for TSP and DAP, respectively.

  4. Mercury poisoning dentistry: high-level indoor air mercury contamination at selected dental sites.

    Science.gov (United States)

    Khwaja, Mahmood A; Abbasi, Maryam Shabbir

    2014-01-01

    Mercury (Hg), also known as quick silver, is an essential constituent of dental amalgam. It is a toxic substance of global concern. Children are more at risk from mercury poisoning which affects their neurological development and brain. In the past, a number of studies at dental sites in many countries have been carried out and reported. The present report briefly describes and discusses our recent investigations carried out at 34 dental sites (teaching institutions, hospitals and private clinics) in Pakistan. It is evident from the data that at many sites the indoor mercury vapor levels exceed far above the permissible limit recommended for safe physical and mental health. At these sites, public in general and the medical, paramedical staff and vulnerable population in particular, are at most serious risk to health resulting from exposure to toxic and hazardous mercury. To minimize such risk, some of the recommendations are, best in-house environmental practices for occupational health and safety, mercury contaminated waste reduction at source, mercury specific legislation and ratification of Minamata convention on mercury by Pakistan and other world governments at the earliest time possible.

  5. Recent study of nanomaterials prepared by inert gas condensation using ultra high vacuum chamber

    Indian Academy of Sciences (India)

    S Ramasamy; D J Smith; P Thangadurai; K Ravichandran; T Prakash; K Padmaprasad; V Sabarinathan

    2005-11-01

    The ultra high vacuum chamber was developed in the Department of Nuclear Physics, University of Madras with the funding from DST, India. This UHV chamber is used to prepare nanocrystalline materials by inert gas condensation technique (IGCT). Nanocrystalline materials such as PbF2, Mn2+-doped PbF2, Sn-doped In2O3 (ITO), ZnO, Al2O3, Ag2O, CdO, CuO, ZnSe:ZnO etc., were prepared by this technique and characterized. Results of some of these materials will be presented in this paper. In solid-state 207Pb NMR on PbF2 a separate signal due to the presence of grain boundary has been observed. The structural phase transition pressure during the phase transformation from the cubic phase to orthorhombic phase under high pressure shows an increase with the decrease in grain size. Presence of electronic centres in nanocrystalline PbF2 is observed from Raman studies and the same has been confirmed by photoluminescence studies. Al2O3 was prepared and 56Fe ions were implanted. After implantation segregation of 56Fe ions was examined by SEM. The oxidation properties of ITO were studied by HRTEM. As against the expectation of oxide coating on individual nanograins of In{Sn alloy, ITO nanograins grew into faceted nanograins on heat treatment in air and O2 atmosphere. The growth of ITO under O2 atmosphere showed pentagon symmetry. The PMN was initially prepared by solid-state reaction. Further, this PMN relaxor material will be used to convert into nanocrystalline PMN by IGCT with sputtering and will be studied.

  6. Yolk-shelled cathode materials with extremely high electrochemical performances prepared by spray pyrolysis

    Science.gov (United States)

    Choi, Seung Ho; Hong, Young Jun; Kang, Yun Chan

    2013-08-01

    A facile, continuous preparation process of yolk-shell-structured lithium-metal oxide powders without a template for use as cathode materials in lithium ion batteries is introduced for the first time. Single and double-shelled LiNi0.5Mn1.5O4 yolk-shell powders as the first target materials are prepared directly by spray pyrolysis from a spray solution with sucrose, at a short residence time of 4 s. Fast combustion and contraction of a carbon-mixed oxide composite intermediate, formed from a micro-sized droplet inside a hot wall reactor maintained at 700 °C, produces the yolk-shell powders. The yolk-shell structure of the precursor powders directly prepared by spray pyrolysis is well maintained even at a high post-treatment temperature of 750 °C. The yolk-shell LiNi0.5Mn1.5O4 powders delivered a 1000th high discharge capacity of 108 mA h g-1 at 10 C. The discharge capacities are as high as 103, 95, and 91 mA h g-1 at extremely high discharge rates of 100, 200, and 300 C and the corresponding specific energy densities are 420, 370, and 328 W h kg-1. The capacity retention at a constant discharge rate of 200 C is 90% after 500 cycles.A facile, continuous preparation process of yolk-shell-structured lithium-metal oxide powders without a template for use as cathode materials in lithium ion batteries is introduced for the first time. Single and double-shelled LiNi0.5Mn1.5O4 yolk-shell powders as the first target materials are prepared directly by spray pyrolysis from a spray solution with sucrose, at a short residence time of 4 s. Fast combustion and contraction of a carbon-mixed oxide composite intermediate, formed from a micro-sized droplet inside a hot wall reactor maintained at 700 °C, produces the yolk-shell powders. The yolk-shell structure of the precursor powders directly prepared by spray pyrolysis is well maintained even at a high post-treatment temperature of 750 °C. The yolk-shell LiNi0.5Mn1.5O4 powders delivered a 1000th high discharge capacity of 108 m

  7. Preparation of activated carbon with high surface area for high-capacity methane storage

    Institute of Scientific and Technical Information of China (English)

    Bingsi Liua; Wenshuo Wanga; Na Wanga; Peter Chak Tong Aub

    2014-01-01

    Activated carbon (AC) was fabricated from corncob, which is cheap and abundant. Experimental parameters such as particle size of corncob, KOH/char weight ratio, and activation temperature and time were optimized to generate AC, which shows high methane sorption capacity. AC has high specific surface area (3227 m2/g), with pore volume and pore size distribution equal to 1.829 cm3/g and ca. 1.7-2.2 nm, respectively. Under the condition of 2◦C and less than 7.8 MPa, methane sorption in the presence of water (Rw=1.4) was as high as 43.7 wt%methane per unit mass of dry AC. The result is significantly higher than those of coconut-derived AC (32 wt%) and ordered mesoporous carbon (41.2 wt%, Rw=4.07) under the same condition. The physical properties and amorphous chaotic structure of AC were characterized by N2 adsorption isotherms, XRD, SEM and HRTEM. Hence, the corncob-derived AC can be considered as a competitive methane-storage material for vehicles, which are run by natural gas.

  8. Preparation of 5N high purified indium by the method of chemical purification-electrolysis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The application of indium requires high purity indium as material. 5N high purity indium had been prepared by the method of a combination of chemically smelting and electrolysis. Smelting time was 10 min, the abstraction rate of cadmium was 80%-90% when used solution of I2-KI and glycerine to smelt indium. 4N metal indium was used as anode, high purity indium as cathode, In2(SO4)3-H2SO4 system as electrolyte, and In content is 100 g/L, pH 2-3 and current density 80-100 A/m2. The thallium was removed by smelting indium using 15% NH4Cl-glycerine solution for 20 min and tin by smelting indium using NaOH and NaNO3 for 20 min. The removed rate of tin was 60%.The product quality of indium reached national standard of 5N high purity indium.

  9. Highly reusability surface loaded metal particles magnetic catalyst microspheres (MCM-MPs) for treatment of dye-contaminated water

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ying; Zhang, Kun, E-mail: kun4219@njtech.edu.cn; Yin, Xiaoshuang; Yang, Wenzhong; Zhu, Hongjun

    2016-04-01

    The metal-deposited magnetic catalyst microspheres (MCM-MPs) were successfully synthesized by one facile, high yield and controllable approach. Here, the bare magnetic microspheres were firstly synthesized according to the solvothermal method. Then silica shell were coated on the surface of the magnetic microspheres via sol–gel method, and subsequently with surface modifying with amino in the purpose to form SiO{sub 2}–NH{sub 2} shell. Thus, metal particles were easily adsorbed into the SiO{sub 2}–NH{sub 2} shell and in-situ reduced by NaBH{sub 4} solution. All the obtained products (MCM-Cu, MCM-Ag, MCM-Pd) which were monodisperse and constitutionally stable were exhibited high magnetization and excellent catalytic activity towards dyes solution reduction. The catalytic rate ratio of MCM-Pd: MCM-Cu: MCM-Ag could be 10:3:1. Besides, some special coordination compound Cu{sub 2}(OH){sub 3}Br had been generated in the in-situ reduced process of MCM-Cu, which produced superior cyclical stability (>20 times) than that of MCM-Ag and MCM-Pd. In all, those highly reusability and great catalytic efficiency of MCM-MPs show promising and great potential for treatment of dye-contaminated water. - Graphical abstract: Surface loaded metal particles magnetic catalyst microspheres MCM-MPs for rapid decolorizing dye-contaminated water: Synthesis, characterization and possible mechanisms. - Highlights: • A simple and high yield synthetic method for fabricate multi MCM-MPs is proposed with adequately optimize. • The highest reusability of MCM-Cu is attribute to the coordination compounds Cu{sub 2}(OH){sub 3}Br. • MCM-MPs show excellent catalytic properties under different situations for various dyes • The catalytic mechanism of MCM-MPs is presented.

  10. Treatment of Perchlorate-Contaminated Groundwater Using Highly-Selective, Regenerable Anion-Exchange Resins at Edwards Air Force Base

    Energy Technology Data Exchange (ETDEWEB)

    Gu, B.

    2003-05-30

    Selective ion exchange is one of the most effective treatment technologies for removing low levels of perchlorate (ClO{sub 4}{sup -}) from contaminated water because of its high efficiency without adverse impacts on the water quality caused by adding or removing any chemicals or nutrients. This report summarizes both the laboratory and a field pilot-scale studies to determine the ability and efficiency of the bifunctional synthetic resins to remove ClO{sub 4}{sup -} from the contaminated groundwater at the Edwards Air Force Base in California. Regeneration of the resins after groundwater treatment was also evaluated using the FeCl{sub 3}-HCl regeneration technique recently developed at Oak Ridge National Laboratory. On the basis of this study, the bifunctional resin, D-3696 was found to be highly selective toward ClO{sub 4}{sup -} and performed much better than one of the best commercial nitrate-selective resins (Purolite A-520E) and more than an order of magnitude better than the Purolite A-500 resin (with a relatively low selectivity). At an influent concentration of {approx} 450 {micro}g/L ClO{sub 4}{sup -} in groundwater, the bifunctional resin bed treated {approx} 40,000 empty bed volumes of groundwater before a significant breakthrough of ClO{sub 4}{sup -} occurred. The presence of relatively high concentrations of chloride and sulfate in site groundwater did not appear to affect the ability of the bifunctional resin to remove ClO{sub 4}{sup -}. However, the presence of high iron or iron oxyhydroxides and/or biomass in groundwater caused a significant fouling of the resin beds and greatly influenced the effectiveness in regenerating the resins sorbed with ClO{sub 4}{sup -}. Under such circumstances, a prefilter ({approx} 0.5-1 {micro}m) was found to be necessary to remove these particulates and to reduce the risk of fouling of the resin beds. Without significant fouling, the resin bed could be effectively regenerated by the FeCl{sub 3} displacement technique

  11. Earthworm casts as a sampling medium – a case study from highly contaminated Hg roasting site Pšenk (Idrija area, Slovenia

    Directory of Open Access Journals (Sweden)

    Tamara Teršič

    2013-12-01

    Full Text Available In this study an interesting sampling medium - earthworm casts was examined in a highly Hg contaminated area. Enrichment factor (EF has been applied to assess elevated concentrations of analyzed elements in earthworm casts and to determine elevated concentrations of these elements in soils and casts with regard to European average concentrations in topsoil. In a previous study (Teršič & Gosar, 2012 it was shown that Hg contents and dispersion in casts from studied roasting site are comparable to those in soil, which indicates that soil contamination is substantially reflected in contamination of earthworm casts. Therefore the comparison between elemental concentrations in earthworm casts and soil was investigated with the intention to assess the reflection of possible soil contamination in casts. Besides Hg contamination, elevated concentrations of As, Ca, Cd, Mo, Pb and U were also determined in earthworm casts. The calculated EFs show moderate enrichment of casts with Ca, Sr and P and minimal enrichment with Mg, Zn and Cu. Cast, SOM (surface organic matter rich soil layer and soil enrichments with regard to the European averages show extreme enrichment of all studied media with Hg, followed by significant enrichment with Mo and Cd and moderate enrichment with As. Spatial distributions of analyzed elements in casts mostly show similar pattern as in soil, however, because of the different nature of different earthworm species and specific properties of different elements, the data about cast contamination can only serve as an approximate prediction about the dispersion and distribution of contaminant in soil.

  12. Influence of soil and hydrocarbon properties on the solvent extraction of high-concentration weathered petroleum from contaminated soils.

    Science.gov (United States)

    Sui, Hong; Hua, Zhengtao; Li, Xingang; Li, Hong; Wu, Guozhong

    2014-05-01

    Petroleum ether was used to extract petroleum hydrocarbons from soils collected from six oil fields with different history of exploratory and contamination. It was capable of fast removing 76-94 % of the total petroleum hydrocarbons including 25 alkanes (C11-C35) and 16 US EPA priority polycyclic aromatic hydrocarbons from soils at room temperature. The partial least squares analysis indicated that the solvent extraction efficiencies were positively correlated with soil organic matter, cation exchange capacity, moisture, pH, and sand content of soils, while negative effects were observed in the properties reflecting the molecular size (e.g., molecular weight and number of carbon atoms) and hydrophobicity (e.g., water solubility, octanol-water partition coefficient, soil organic carbon partition coefficient) of hydrocarbons. The high concentration of weathered crude oil at the order of 10(5) mg kg(-1) in this study was demonstrated adverse for solvent extraction by providing an obvious nonaqueous phase liquid phase for hydrocarbon sinking and increasing the sequestration of soluble hydrocarbons in the insoluble oil fractions during weathering. A full picture of the mass distribution and transport mechanism of petroleum contaminants in soils will ultimately require a variety of studies to gain insights into the dynamic interactions between environmental indicator hydrocarbons and their host oil matrix.

  13. Radial metal concentration profiles in trees growing on highly contaminated soils.

    Science.gov (United States)

    Superville, Pierre-Jean; de Winter, Niels; Phung, Anh Tuan; Proix, Nicolas; Baeyens, Willy; Gao, Yue

    2017-04-01

    The soil around Metaleurop, a big smelter, is heavily contaminated by Zn, Pb, Cd and Cu. In order to compare the impact of different soil amendments on the metal availability to trees, the polluted soil section was divided in a reference parcel and two others with either sulfo-calcic or silico-aluminous ash amendments. Five different tree species were planted on the parcels and the uptake of heavy metals in these trees was studied. Total and labile metal fractions were assessed in each of the 3 parcels. The mobility and assimilation of the metals was highest in the non-amended, reference soil parcel which had the lowest pH, organic matter and carbonate content. In all soils, pH decreased while organic matter content and mobility of the metals increased over time. Highest bulk concentrations of trace metals were found in white willow trees (Salix alba L.). Laser ablation-ICPMS was used to study changes in metal accumulation over a period of 10 years after planting the trees. The radial metal profiles in the trunk core samples varied between elements and tree species, however, in all willow trees the radial Cd and Zn profiles were significantly correlated. Radial pollutant concentration patterns are discussed in terms of seasonal effects, health status, tree species and metal mobility in the soil. For Cd and Zn, the profiles were influenced by their mobility in the soils. In general, periodical patterns were observed for Pb. Cu concentration profiles were decreasing over time, with the strongest decrease in the initial growth period.

  14. Highly flexible magnetic composite aerogels prepared by using cellulose nanofibril networks as templates.

    Science.gov (United States)

    Liu, Shilin; Yan, Qiufang; Tao, Dandan; Yu, Tengfei; Liu, Xiaoya

    2012-06-20

    Nanostructured cellulose nanofibrils can form ductile or tough networks that are suitable templates for the creation of materials with functional properties. In this work, a facile method has been developed for the preparation of magnetic hybrid cellulose aerogels. The preparation processes followed by two steps, firstly, preparation of cellulose hydrogel films from LiOH/urea solvent, then CoFe2O4 nanoparticles were synthesized in the porous structured cellulose scaffolds. After being freeze-dried, CoFe2O4/cellulose magnetic aerogels were obtained. The porosity of the composite aerogels ranged from 78 to 52% with pore size distribution in a few tens of nanometers. The internal specific surface areas were around 300-320 m2/g, and the densities were in the range of 0.25-0.39 g/cm3. The hybrid aerogels showed improved mechanical strength, superparamagnetic properties. Unlike solvent-swollen gels and ferrogels, the magnetic composite aerogels were lightweight, flexibility, high porosity and with large specific surface area and could be expected to be used in many fields. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Preparation and Mechanical Properties of Glass Coats with High Temperature Radar Absorber

    Institute of Scientific and Technical Information of China (English)

    ZHU Dong-mei; LUO Fa; XIONG Liang-ming; ZHOU Wan-cheng

    2006-01-01

    BaO-La2O3-B2O3 (BLB) glass, suitable to be used as a sealing between metals, was chosen to be the binder in preparing glass coats on the Ti-alloy substrate. The SiCN nano-powder was introduced as the filler for the absorbing coat because it is considered to be a good high temperature absorber. The effect of the coating temperature and coating time on the tensile strength of the glass coat was investigated and the proper coating parameters to get good mechanical properties were determined. In addition, the effects of the SiCN content on the tensile strength of the absorbing coat were also discussed. Results show that it is possible to prepare the glass coat using the BLB glass as a binder. That the coat formed at 730 ℃ for 30 min has the best tensile strength witnesses 730 ℃, 30 min to be the proper parameter to prepare the glass coat. The BLB glass coat without SiCN powder possesses good tensile strength and the introduction of the SiCN absorber into the glass coat will lower the tensile strength. As the SiCN content increases, the tensile strength of the absorbing coat decreases, which could be attributed to the aggregation of SiCN in the coats.

  16. Graphene prepared by one-pot solvent exfoliation as a highly sensitive platform for electrochemical sensing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Can; Cheng, Qin [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Wu, Kangbing, E-mail: kbwu@hust.edu.cn [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Wu, Gang [Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Li, Qing, E-mail: qing_li_2@brown.edu [Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2014-05-01

    Highlights: • Graphene was prepared by one-step solvent exfoliation as superior electrode material. • Compared with RGO, prepared graphene exhibited stronger signal enhancement. • A widespread and highly-sensitive electrochemical sensing platform was constructed. - Abstract: Graphene was easily obtained via one-step ultrasonic exfoliation of graphite powder in N-methyl-2-pyrrolidone. Scanning electron microscopy, transmission electron microscopy, Raman and particle size measurements indicated that the exfoliation efficiency and the amount of produced graphene increased with ultrasonic time. The electrochemical properties and analytical applications of the resulting graphene were systematically studied. Compared with the predominantly-used reduced graphene oxides, the obtained graphene by one-step solvent exfoliation greatly enhanced the oxidation signals of various analytes, such as ascorbic acid (AA), dopamine (DA), uric acid (UA), xanthine (XA), hypoxanthine (HXA), bisphenol A (BPA), ponceau 4R, and sunset yellow. The detection limits of AA, DA, UA, XA, HXA, BPA, ponceau 4R, and sunset yellow were evaluated to be 0.8 μM, 7.5 nM, 2.5 nM, 4 nM, 10 nM, 20 nM, 2 nM, and 1 nM, which are much lower than the reported values. Thus, the prepared graphene via solvent exfoliation strategy displays strong signal amplification ability and holds great promise in constructing a universal and sensitive electrochemical sensing platform.

  17. Overview of the PREPARE WP3: management of contaminated goods in post-accidental situation – Synthesis of European stakeholders' panels

    NARCIS (Netherlands)

    Charron, S.; Lafage, S.; Asselt, Van E.; Baptista, M.; Bourgondiën, Van M.; Brandhoff, P.; Cabianca, T.; Camps, J.; Cessac, B.; Crouail, P.; Durand, V.; Gallego, E.; Gil, O.; Holmes, S.; Hourdakis, C.; Jones, K.; Kamenopoulou, V.; Lecomte, J.F.; Liland, A.; Lopes, I.; Madruga, M.J.; Martins, J.O.; McMahon, C.; Montero, M.; Murith, C.; Olyslaegers, G.; Organo, C.; Paiva, I.; Peltonen, T.; Portugal, L.; Potiriadis, C.; Prades, A.; Reis, M.; Rossignol, N.; Schneider, T.; Sala, R.; Smith, V.; Tafili, V.; Teles, P.; Tomkiv, Y.; Trueba, C.; Turcanu, C.; Turtiainen, T.; Twenhöfel, C.; Vaz, P.; Duranova, Tatiana; Raskob, Wolfgang; Schneider, Thierry

    2016-01-01

    Recommendations and requirements for the management of foodstuffs including drinking water and
    feedstuffs (but not other commodities) contaminated after a nuclear accident or a radiological event have been developed by
    international bodies such as Codex Alimentarius Commission or European Un

  18. Personal protective equipment for preventing highly infectious diseases due to exposure to contaminated body fluids in healthcare staff.

    Science.gov (United States)

    Verbeek, Jos H; Ijaz, Sharea; Mischke, Christina; Ruotsalainen, Jani H; Mäkelä, Erja; Neuvonen, Kaisa; Edmond, Michael B; Sauni, Riitta; Kilinc Balci, F Selcen; Mihalache, Raluca C

    2016-04-19

    In epidemics of highly infectious diseases, such as Ebola Virus Disease (EVD) or SARS, healthcare workers (HCW) are at much greater risk of infection than the general population, due to their contact with patients' contaminated body fluids. Contact precautions by means of personal protective equipment (PPE) can reduce the risk. It is unclear which type of PPE protects best, what is the best way to remove PPE, and how to make sure HCWs use PPE as instructed. To evaluate which type or component of full-body PPE and which method of donning or removing (doffing) PPE have the least risk of self-contamination or infection for HCWs, and which training methods most increase compliance with PPE protocols. We searched MEDLINE (PubMed up to 8 January 2016), Cochrane Central Register of Trials (CENTRAL up to 20 January 2016), EMBASE (embase.com up to 8 January 2016), CINAHL (EBSCOhost up to 20 January 2016), and OSH-Update up to 8 January 2016. We also screened reference lists of included trials and relevant reviews, and contacted NGOs and manufacturers of PPE. We included all eligible controlled studies that compared the effect of types or components of PPE in HCWs exposed to highly infectious diseases with serious consequences, such as EVD and SARS, on the risk of infection, contamination, or noncompliance with protocols. This included studies that simulated contamination with fluorescent markers or a non-pathogenic virus.We also included studies that compared the effect of various ways of donning or removing PPE, and the effects of various types of training in PPE use on the same outcomes. Two authors independently selected studies, extracted data and assessed risk of bias in included trials. We intended to perform meta-analyses but we did not find sufficiently similar studies to combine their results. We included nine studies with 1200 participants evaluating ten interventions. Of these, eight trials simulated the exposure with a fluorescent marker or virus or bacteria

  19. Groundwater resource vulnerability and spatial variability of nitrate contamination: Insights from high density tubewell monitoring in a hard rock aquifer.

    Science.gov (United States)

    Buvaneshwari, Sriramulu; Riotte, Jean; Sekhar, M; Mohan Kumar, M S; Sharma, Amit Kumar; Duprey, Jean Louis; Audry, Stephane; Giriraja, P R; Praveenkumarreddy, Yerabham; Moger, Hemanth; Durand, Patrick; Braun, Jean-Jacques; Ruiz, Laurent

    2017-02-01

    Agriculture has been increasingly relying on groundwater irrigation for the last decades, leading to severe groundwater depletion and/or nitrate contamination. Understanding the links between nitrate concentration and groundwater resource is a prerequisite for assessing the sustainability of irrigated systems. The Berambadi catchment (ORE-BVET/Kabini Critical Zone Observatory) in Southern India is a typical example of intensive irrigated agriculture and then an ideal site to study the relative influences of land use, management practices and aquifer properties on NO3 spatial distribution in groundwater. The monitoring of >200 tube wells revealed nitrate concentrations from 1 to 360mg/L. Three configurations of groundwater level and elevation gradient were identified: i) NO3 hot spots associated to deep groundwater levels (30-60m) and low groundwater elevation gradient suggest small groundwater reserve with absence of lateral flow, then degradation of groundwater quality due to recycling through pumping and return flow; ii) high groundwater elevation gradient, moderate NO3 concentrations suggest that significant lateral flow prevented NO3 enrichment; iii) low NO3 concentrations, low groundwater elevation gradient and shallow groundwater indicate a large reserve. We propose that mapping groundwater level and gradient could be used to delineate zones vulnerable to agriculture intensification in catchments where groundwater from low-yielding aquifers is the only source of irrigation. Then, wells located in low groundwater elevation gradient zones are likely to be suitable for assessing the impacts of local agricultural systems, while wells located in zones with high elevation gradient would reflect the average groundwater quality of the catchment, and hence should be used for regional mapping of groundwater quality. Irrigation with NO3 concentrated groundwater induces a "hidden" input of nitrogen to the crop which can reach 200kgN/ha/yr in hotspot areas, enhancing

  20. Lowering the environmental impact of high-kappa/ metal gate stack surface preparation processes

    Science.gov (United States)

    Zamani, Davoud

    . The second objective of this study is to develop new rinse methods to reduce water and energy usage during rinsing and cleaning of hafnium based high-κ materials in single wafer-cleaning tools. It is necessary to have a metrology method which can study the effect of all process parameters that affect the rinsing by knowing surface concentration of contaminants in patterned hafnium based oxides and silicate wafers. This has been achieved by the introduction of a metrology method at The University of Arizona which monitors the transport of contaminant concentrations inside micro- and nano- structures. This is the only metrology which will be able to provide surface concentration of contaminants inside hafnium based oxides and silicate micro-structures while the rinsing process is taking place. The goal of this research is to study the effect of various process parameters on rinsing of patterned hafnium based oxides and silicate wafers, and modify a metrology method for end point detection.

  1. Plasmonic photosensitization of polyaniline prepared by a novel process for high-performance flexible photodetector.

    Science.gov (United States)

    Barman, Tapan; Pal, Arup R

    2015-02-01

    We report the synthesis of a polyaniline (PAni)-gold nanoparticle (AuNP) composite thin film in a single step. A flexible high-performance visible photodetector is constructed using PAni-AuNP composite with low loading of AuNP, and optoelectronic properties of the device are evaluated. The present study demonstrates that a plasmonic hybrid nanocomposite prepared by a single-step novel plasma-based dry process could solve the low lifetime and performance-related issues of organic optoelectronic devices.

  2. Tenside-free preparation of nanogels with high functional β-cyclodextrin content.

    Science.gov (United States)

    Kettel, Markus J; Hildebrandt, Haika; Schaefer, Karola; Moeller, Martin; Groll, Juergen

    2012-09-25

    We present the preparation of ultrafine (R(h), 50 -150 nm) nanogels through tenside-free condensation of reactive prepolymers with β-cyclodextrin (β-CD) in water. These nanogels possess a maximum content of 60 wt % functional β-CD that can form inclusion complexes as demonstrated by dye sorption with phenolphthalein. Aside of this extremely high uptake capacity to hydrophobic molecules, the nanogels also show good adhesion to surfaces in homogeneous distribution with size of R(h) of 25 nm under dry conditions.

  3. An investigation of the preparation of high molecular weight perfluorocarbon polyethers

    Science.gov (United States)

    Watts, R. O.; Tarrant, P.

    1972-01-01

    High molecular weight perfluorocarbon polyether gums were obtained by photolysis of perfluorodienes and discyl fluorides containing a perfluorocarbon polyether backbond. The materials obtained are represented by chemical formulas. A method was developed whereby reactive acyl fluoride and trifluorovinyl end groups are converted into inert structures. In order to investigate the possible preparation of difunctional molecules which may be useful in polymer synthesis, the reactions of hexafluoropropene oxide (HFPO) with Grignard and organolithium reagents have been studied. Reactions of various nucleophilic reagents with HFPO were also investigated.

  4. Curating and Preparing High-Throughput Screening Data for Quantitative Structure-Activity Relationship Modeling.

    Science.gov (United States)

    Kim, Marlene T; Wang, Wenyi; Sedykh, Alexander; Zhu, Hao

    2016-01-01

    Publicly available bioassay data often contains errors. Curating massive bioassay data, especially high-throughput screening (HTS) data, for Quantitative Structure-Activity Relationship (QSAR) modeling requires the assistance of automated data curation tools. Using automated data curation tools are beneficial to users, especially ones without prior computer skills, because many platforms have been developed and optimized based on standardized requirements. As a result, the users do not need to extensively configure the curation tool prior to the application procedure. In this chapter, a freely available automatic tool to curate and prepare HTS data for QSAR modeling purposes will be described.

  5. Preparation and hydrogen 8as sensitive characteristics of highly ordered titania nanotube arrays

    Institute of Scientific and Technical Information of China (English)

    JI HuiMing; LU HuiXiang; MA DongFang; YU JianJun; MA ShiCai

    2008-01-01

    In this paper, we report the growth and characteristics of titania nanotube arrays prepared by anodic oxidation and then annealed in an oxygen atmosphere at 500℃. The titania nanotube arrays presented high sensitivity to hydrogen gas. The crystalline phase of the samples was checked by X-ray diffraction (XRD). The differences in the nanotubes morphology attributed to the etched samples due to anodiza-tion potential, reaction time and the electrolyte concentration were analyzed by scanning electron mi-croscopy (SEM). The gas sensitive parameters of the samples were obtained from resistance, the re-sponse time and the recovery time at different temperatures.

  6. [Depolymerization of high-molecular-weight chitosan by the enzyme preparation Celloviridine G20x].

    Science.gov (United States)

    Il'ina, A V; Tkacheva, Iu V; Varlamov, V P

    2002-01-01

    A low-molecular-weight water-soluble chitosan was obtained from high-molecular-weight crab chitosan using the enzyme preparation Celloviridine G20x. Optimum conditions for the enzymatic hydrolysis were designed. The reaction should be performed for 4 h in a sodium-acetate buffer (pH 5.2) at 55 degrees C and the enzyme to substrate ratio of 1:400. Fractional extraction of chitosan hydrolysate by aqueous ethanol (ethanol: distilled water) yielded fractions with molecular weights in the range 3.2-26.4 kDa.

  7. High-purity cobalt thin films with perpendicular magnetic anisotropy prepared by chemical vapor deposition

    Science.gov (United States)

    Ootera, Yasuaki; Shimada, Takuya; Kado, Masaki; Quinsat, Michael; Morise, Hirofumi; Nakamura, Shiho; Kondo, Tsuyoshi

    2015-11-01

    A study of the chemical vapor deposition (CVD) of high-purity cobalt thin films is described. The Co layer prepared by a thermal CVD technique with a Pt/Ta underlayer and a Pt cap layer shows a saturation magnetization (Ms) of ∼1.8 T and perpendicular magnetic anisotropy (PMA) with an anisotropy energy (Ku) of ∼105 J/m3. The cobalt thickness dependence of Ku reveals that the interfacial anisotropy at the Pt/Co interface is most likely the origin of the obtained PMA.

  8. Preparation of high-molecular weight DNA and metagenomic libraries from soils and hot springs.

    Science.gov (United States)

    Reigstad, Laila J; Bartossek, Rita; Schleper, Christa

    2011-01-01

    Metagenomics has become an important tool for the characterization of microorganisms, as it is independent of their enrichment or cultivation in the laboratory. Its application has led to the discovery of metabolisms from widespread, yet uncharacterized organisms such as the ammonia-oxidizing archaea. Different approaches ranging from the generation of short sequence reads by direct use of high-throughput sequencing technologies to the construction and sequencing of large-insert DNA libraries are being employed. For these purposes, DNA of high quality needs to be prepared from an environmental sample, which is a particular challenge for soils and sediments. Here we describe the methods used for the isolation of high-molecular weight (hmw) DNA from soil and hot spring samples, the subsequent production of large-insert metagenomic libraries, and the analysis of the resulting genomic fragments. Detailed step-by-step procedures include (1) how to isolate good-quality hmw DNA from soils and mud; (2) how to prepare the DNA for cloning; (3) how to efficiently establish, grow, pick, replicate, and store the large-insert metagenomic fosmid library; and finally, (4) how to screen the library for genes of interest.

  9. Preparation and Characterization of Highly Aligned Carbon Nanotubes/Polyacrylonitrile Composite Nanofibers

    Directory of Open Access Journals (Sweden)

    Yanhua Song

    2017-01-01

    Full Text Available In the electrospinning process, a modified parallel electrode method (MPEM, conducted by placing a positively charged ring between the needle and the parallel electrode collector, was used to fabricate highly aligned carbon nanotubes/polyacrylonitrile (CNTs/PAN composite nanofibers. Characterizations of the samples—such as morphology, the degree of alignment, and mechanical and conductive properties—were investigated by a combination of scanning electron microscopy (SEM, transmission electron microscopy (TEM, universal testing machine, high-resistance meter, and other methods. The results showed the MPEM could improve the alignment and uniformity of electrospun CNTs/PAN composite nanofibers, and enhance their mechanical and conductive properties. This meant the successful preparation of highly aligned CNT-reinforced PAN nanofibers with enhanced physical properties, suggesting their potential application in appliances and communication areas.

  10. Preparation and characterization of boron nitride/carbon fiber composite with high specific surface area

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yan; Fan, Mingwen [Wuhan Univ. (China). Key Laboratory for Oral Biomedical Engineering; Yuan, Songdong; Xiong, Kun; Hu, Kunpeng; Luo, Yi [Hubei Univ. of Technology, Wuhan (China). School of Chemistry and Chemical Engineering; Li, Dong [Hubei Univ. of Technology, Wuhan (China). School of Chemistry and Chemical Engineering; Oxford Univ. (United Kingdom). Chemistry Research Lab.

    2014-06-15

    Boron nitride can be used as a good catalyst carrier because of its high thermal conductivity and chemical stability. However, a high specific surface area of boron nitride is still desirable. In this work, a carbon fiber composite coated with boron nitride villous nano-film was prepared, and was also characterized by means of scanning electron microscopy, high resolution transmission electron microscopy, Fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller analysis. The results indicated that the carbon fibers were covered by uniform villous boron nitride films whose thickness was about 150 - 200 nm. The specific surface area of the boron nitride/carbon fiber composite material was 96 m{sup 2} g{sup -1}, which was markedly improved compared with conventional boron nitride materials. (orig.)

  11. Preparation of water-soluble graphene nanoplatelets and highly conductive films

    KAUST Repository

    Xu, Xuezhu

    2017-08-11

    This paper tackles the challenge of preparation stable, highly concentrated aqueous graphene dispersions. Despite tremendous recent interest, there has been limited success in developing a method that ensures the total dispersion of non-oxidized, defect-free graphene nanosheets in water. This study successfully demonstrates that few-layer graphene nanoplatelets (GNPs) can form highly concentrated aqueous colloidal solutions after they have been pretreated in a low-concentration inorganic sodium-hypochlorite and sodium-bromide salted aqueous solvent. This method retains the graphitic structure as evidenced by nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. Vacuum-filtrated freestanding films demonstrate an electrical conductivity as high as 3000 S m−1. This dispersion technique is believed to be applicable not only for GNPs, but also for dispersing other types of graphitic materials, including fullerenes, single/double/multi-walled carbon nanotubes, graphene nanoribbons and etc.

  12. High-field magnetization process of granular Co-Cu alloys prepared by melt spinning

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    High solid-solubility Co15Cu35 alloys have been prepared by melt spinning and submitted to isothermal and anisothermal annealing to obtain granular alloys.The X-ray diffraction(XRD) patterns were measured to invesugate the decomposition of supersaturated solid solution induced by annealing.The atomic diffusion and structural evolution during the heat treatment were investigated.In view of the problems limiting their appllcation.the high-field magneazation curves were measured.By a fit to the high-field magnetization curves,the granuiar alloys are found hard to be magnetically saturated at the early stage of nucleation and growth.The magnetization behavior was correlaced to the annealed-induced structureal evolution and also to the magnetoresistance effect.

  13. [Simultaneously preparation of grams of high purity tyrosol, crenulatin and salidroside from Rhodiola crenulata].

    Science.gov (United States)

    Luo, Xin; Wang, Xue-jing; Li, Shi-ping; Zhang, Qiao; Zhao, Yi-wu; Huang Wen-zhe; Wang, Zhen-zhong; Xiao, Wei

    2015-04-01

    Tyrosol, crenulatin and salidroside are the main active constituents of Rhodiola crenulata, with extensive pharmacological activities. In the study, grams of high purity tyrosol, crenulatin and salidroside were simultaneously separated from R. crenulata by the first time. Firstly, R. crenulata was extracted by 70% alcohol. Then, with the yields of three compounds as the index, the macroporous resin was optimized. At last, grams of high purity tyrosol, crenulatin and salidroside were isolated by D-101 macroporousresin, purified by column chromatography. Detected by HPLC, the purity of three compounds were higher than 98%. This method has the advantages of simple process and operation, less dosage of organic solvent, highly yield and reproducibility, suitable for the simultaneously preparation of tyrosol, crenulatin and salidroside.

  14. High quality thin films of thermoelectric misfit cobalt oxides prepared by a chemical solution method

    Science.gov (United States)

    Rivas-Murias, Beatriz; Manuel Vila-Fungueiriño, José; Rivadulla, Francisco

    2015-01-01

    Misfit cobaltates ([Bi/Ba/Sr/Ca/CoO]nRS[CoO2]q) constitute the most promising family of thermoelectric oxides for high temperature energy harvesting. However, their complex structure and chemical composition makes extremely challenging their deposition by high-vacuum physical techniques. Therefore, many of them have not been prepared as thin films until now. Here we report the synthesis of high-quality epitaxial thin films of the most representative members of this family of compounds by a water-based chemical solution deposition method. The films show an exceptional crystalline quality, with an electrical conductivity and thermopower comparable to single crystals. These properties are linked to the epitaxial matching of the rock-salt layers of the structure to the substrate, producing clean interfaces free of amorphous phases. This is an important step forward for the integration of these materials with complementary n-type thermoelectric oxides in multilayer nanostructures. PMID:26153533

  15. High quality thin films of thermoelectric misfit cobalt oxides prepared by a chemical solution method.

    Science.gov (United States)

    Rivas-Murias, Beatriz; Manuel Vila-Fungueiriño, José; Rivadulla, Francisco

    2015-07-08

    Misfit cobaltates ([Bi/Ba/Sr/Ca/CoO]n(RS)[CoO2]q) constitute the most promising family of thermoelectric oxides for high temperature energy harvesting. However, their complex structure and chemical composition makes extremely challenging their deposition by high-vacuum physical techniques. Therefore, many of them have not been prepared as thin films until now. Here we report the synthesis of high-quality epitaxial thin films of the most representative members of this family of compounds by a water-based chemical solution deposition method. The films show an exceptional crystalline quality, with an electrical conductivity and thermopower comparable to single crystals. These properties are linked to the epitaxial matching of the rock-salt layers of the structure to the substrate, producing clean interfaces free of amorphous phases. This is an important step forward for the integration of these materials with complementary n-type thermoelectric oxides in multilayer nanostructures.

  16. Preparation for high-acuity clinical placement: confidence levels of final-year nursing students

    Directory of Open Access Journals (Sweden)

    Porter J

    2013-04-01

    Full Text Available Joanne Porter, Julia Morphet, Karen Missen, Anita Raymond School of Nursing and Midwifery, Monash University, Churchill, VIC, Australia Aim: To measure final-year nursing students’ preparation for high-acuity placement with emphasis on clinical skill performance confidence. Background: Self-confidence has been reported as being a key component for effective clinical performance, and confident students are more likely to be more effective nurses. Clinical skill performance is reported to be the most influential source of self-confidence. Student preparation and skill acquisition are therefore important aspects in ensuring students have successful clinical placements, especially in areas of high acuity. Curriculum development should aim to assist students with their theoretical and clinical preparedness for the clinical environment. Method: A modified pretest/posttest survey design was used to measure the confidence of third-year undergraduate nursing students (n = 318 for placement into a high-acuity clinical setting. The survey comprised four questions related to clinical placement and prospect of participating in a cardiac arrest scenario, and confidence rating levels of skills related to practice in a high-acuity setting. Content and face validity were established by an expert panel (α = 0.90 and reliability was established by the pilot study in 2009. Comparisons were made between confidence levels at the beginning and end of semester. Results: Student confidence to perform individual clinical skills increased over the semester; however their feelings of preparedness for high-acuity clinical placement decreased over the same time period. Reported confidence levels improved with further exposure to clinical placement. Conclusion: There may be many external factors that influence students’ perceptions of confidence and preparedness for practice. Further research is recommended to identify causes of poor self-confidence in final-year nursing

  17. High-performance ion mobility spectrometry with direct electrospray ionization (ESI-HPIMS) for the detection of additives and contaminants in food

    Energy Technology Data Exchange (ETDEWEB)

    Midey, Anthony J., E-mail: anthony.midey@excellims.com; Camacho, Amanda; Sampathkumaran, Jayanthi; Krueger, Clinton A.; Osgood, Mark A.; Wu, Ching

    2013-12-04

    Graphical abstract: -- Highlights: •A new ESI source was built for direct ionization from syringe. •Phthalates, food dyes, and sweeteners detected with high-performance IMS. •Phthalates directly detected in cola, soy bubble tea matrices with simple treatment. -- Abstract: High-performance ion mobility spectrometry (HPIMS) with an electrospray ionization (ESI) source detected a series of food contaminants and additive compounds identified as critical to monitoring the safety of food samples. These compounds included twelve phthalate plasticizers, legal and illegal food and cosmetic dyes, and artificial sweeteners that were all denoted as detection priorities. HPIMS separated and detected the range of compounds with a resolving power better than 60 in both positive and negative ion modes, comparable to the commonly used high-performance liquid chromatography (HPLC) methods, but with most acquisition times under a minute. The reduced mobilities, K{sub 0}, have been determined, as have the linear response ranges for ESI-HPIMS, which are 1.5–2 orders of magnitude for concentrations down to sub-ng μL{sup −1} levels. At least one unique mobility peak was seen for two subsets of the phthalates grouped by the country where they were banned. Furthermore, ESI-HPIMS successfully detected low nanogram levels of a phthalate at up to 30 times lower concentration than international detection levels in both a cola matrix and a soy-based bubble tea beverage using only a simplified sample treatment. A newly developed direct ESI source (Directspray) was combined with HPIMS to detect food-grade dyes and industrial dye adulterants, as well as the sweeteners sodium saccharin and sodium cyclamate, with the same good performance as with the phthalates. However, the Directspray method eliminated sources of carryover and decreased the time between sample runs. Limits-of-detection (LOD) for the analyte standards were estimated to be sub-ng μL{sup −1} levels without extensive

  18. A Developmental Perspective on Workplace Readiness: Preparing High School Students for Success. Research Brief, Publication #2009-24

    Science.gov (United States)

    Lippman, Laura; Keith, Julie

    2009-01-01

    Attention has been focused for decades on the need to improve high school students' preparation for the workplace. Employers report that nearly half of their entry-level employees are inadequately prepared and lack basic communication and critical thinking skills as well as a work ethic. Although a postsecondary credential is considered necessary…

  19. Poly(vinyl alcohol) composite films with high percent elongation prepared from amylose-fatty ammonium salt inclusion complexes

    Science.gov (United States)

    Amylose inclusion complexes prepared from cationic fatty ammonium salts and jet-cooked high amylose starch were combined with poly(vinyl alcohol) (PVOH) to form glycerol-plasticized films. Their tensile properties were compared with similar films prepared previously with analogous anionic fatty acid...

  20. Biomagnification of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls in a highly contaminated freshwater food web from South China.

    Science.gov (United States)

    Wu, Jiang-Ping; Luo, Xiao-Jun; Zhang, Ying; Yu, Mei; Chen, She-Jun; Mai, Bi-Xian; Yang, Zhong-Yi

    2009-03-01

    To evaluate the biomagnification extent of polybrominated diphenyls ethers (PBDEs) and polychlorinated biphenyls (PCBs) in a highly contaminated freshwater food web from South China, trophic magnification factors (TMFs) for 18 PBDE congeners and 53 PCB congeners were calculated. The TMF values ranged 0.26-4.47 for PBDEs and 0.75-5.10 for PCBs. Forty-five of 53 PCBs and BDEs 47, 100 and 154 had TMFs greater than one, suggesting their biomagnification in the present food web. The TMFs for PBDEs were generally smaller than those for PCBs with the same degree of halogenation, indicating a lower biomagnification potential for PBDEs compared to PCBs. For PCBs, it followed a parabolic relationship between TMFs and logK(OW) (octanol-water partition coefficient). However, this relationship was not significant for PBDEs, possibly due to the more complex behaviors of PBDEs in the food web (e.g., metabolism), compared to that of PCBs.

  1. Transformation products of emerging contaminants in the environment and high-resolution mass spectrometry: a new horizon.

    Science.gov (United States)

    Picó, Yolanda; Barceló, Damià

    2015-08-01

    It is crucial to study the presence of transformation products (TPs) of emerging contaminants that can be potentially found in the environment after biological or chemical degradation. This review focuses on the potential and shortcomings of high-resolution mass spectrometry (HRMS) to identify these TPs, with emphasis on recent developments in mass analyzers, data evaluation, and compound identification workflows and applications. Advances in HRMS technologies, including direct introduction or in-line chromatographic separation modes, ionization techniques, mass analyzers, and detection methods, have led to powerful tools to assess the molecular changes and the opening of new horizons to identify unknown molecules. Advances in HRMS pertaining to the generation of analytical data for the main methods to identify TPs, including nontargeted and targeted approaches as they are applied to elucidate the structure of TPs, are also discussed.

  2. Understanding the paradox of selenium contamination in mercury mining areas: high soil content and low accumulation in rice.

    Science.gov (United States)

    Zhang, Hua; Feng, Xinbin; Jiang, Chengxin; Li, Qiuhua; Liu, Yi; Gu, Chunhao; Shang, Lihai; Li, Ping; Lin, Yan; Larssen, Thorjørn

    2014-05-01

    Rice is an important source of Se for billions of people throughout the world. The Wanshan area can be categorized as a seleniferous region due to its high soil Se content, but the Se content in the rice in Wanshan is much lower than that from typical seleniferous regions with an equivalent soil Se level. To investigate why the Se bioaccumulation in Wanshan is low, we measured the soil Se speciation using a sequential partial dissolution technique. The results demonstrated that the bioavailable species only accounted for a small proportion of the total Se in the soils from Wanshan, a much lower quantity than that found in the seleniferous regions. The potential mechanisms may be associated with the existence of Hg contamination, which is likely related to the formation of an inert Hg-Se insoluble precipitate in soils in Wanshan.

  3. Preparative separation of polyphenols from water-soluble fraction of Chinese propolis using macroporous absorptive resin coupled with preparative high performance liquid chromatography.

    Science.gov (United States)

    Li, Aifeng; Xuan, Hongzhuan; Sun, Ailing; Liu, Renmin; Cui, Jichun

    2016-02-15

    In this study, a preparative separation method was developed for isolation of eleven polyphenols from water-soluble fraction of Chinese propolis using macroporous absorptive resin (MAR) coupled with preparative high performance liquid chromatography (PHPLC). Water-soluble fraction of Chinese propolis was first "prefractioned" using MAR, which yielded four subfractions. The four subfractions were then isolated by PHPLC with an isocratic elution of methanol-water. Finally, eleven polyphenols were purified from Chinese propolis including caffeic acid, ferulic acid, isoferulic acid, 3,4-dimethoxy cinnamic acid, pinobanksin, caffeic acid benzyl ester, caffeic acid phenethyl ester, apigenin, pinocembrin, chrysin and galangin. The purities of the compounds were determined by HPLC and the chemical structures were confirmed by UV and NMR analysis. The method developed was simple, effective, rapid, scalable and economical, and it was a promising basis for large-scale preparation of multiple components from natural products.

  4. Preparing and Restoring Composite Resin Restorations. The Advantage of High Magnification Loupes or the Dental Surgical Operating Microscope.

    Science.gov (United States)

    Mamoun, John

    2015-01-01

    Use of magnification, such as 6x to 8x binocular surgical loupes or the surgical operating microscope, combined with co-axial illumination, may facilitate the creation of stable composite resin restorations that are less likely to develop caries, cracks or margin stains over years of service. Microscopes facilitate observation of clinically relevant microscopic visual details, such as microscopic amounts of demineralization or caries at preparation margins; microscopic areas of soft, decayed tooth structure; microscopic amounts of moisture contamination of the preparation during bonding; or microscopic marginal gaps in the composite. Preventing microscope-level errors in composite fabrication can result in a composite restoration that, at initial placement, appears perfect when viewed under 6x to 8x magnification and which also is free of secondary caries, marginal staining or cracks at multi-year follow-up visits.

  5. Preparation of chitosan/tripolyphosphate nanoparticles with highly tunable size and low polydispersity.

    Science.gov (United States)

    Sawtarie, Nader; Cai, Yuhang; Lapitsky, Yakov

    2017-09-01

    Nanoparticles prepared through the ionotropic gelation of chitosan with tripolyphosphate (TPP) have been extensively studied as vehicles for drug and gene delivery. Though a number of these works have focused on preparing particles with narrow size distributions, the monodisperse particles produced by these methods have been limited to narrow size ranges (where the average particle size was not varied by more than twofold). Here we show how, by tuning the NaCl concentration in the parent chitosan and TPP solutions, low-polydispersity particles with z-average diameters ranging between roughly 100 and 900nm can be prepared. Further, we explore how the size of these particles depends on the method by which the TPP is mixed into the chitosan solution, specifically comparing: (1) single-shot mixing; (2) dropwise addition; and (3) a dilution technique, where chitosan and TPP are codissolved at a high (gelation-inhibiting) ionic strength and then diluted to lower ionic strengths to trigger gelation. Though the particle size increases sigmoidally with the NaCl concentration for all three mixing methods, the dilution method delivers the most uniform/gradual size increase - i.e., it provides the most precise control. Also investigated are the effects of mixture composition and mixing procedure on the particle yield. These reveal the particle yield to increase with the chitosan/TPP concentration, decrease with the NaCl concentration, and vary only weakly with the mixing protocol; thus, at elevated NaCl concentrations, it may be beneficial to increase chitosan and TPP concentrations to ensure high particle yields. Finally, possible pitfalls of the salt-assisted size control strategy (and their solutions) are discussed. Taken together, these findings provide a simple and reliable method for extensively tuning chitosan/TPP particle size while maintaining narrow size distributions. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Facile preparation of nitrogen-doped hierarchical porous carbon with high performance in supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Kun [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Kong, Ling-Bin, E-mail: konglb@lut.cn [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Shen, Kui-Wen; Dai, Yan-Hua; Shi, Ming; Hu, Bing [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Luo, Yong-Chun; Kang, Long [School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China)

    2016-02-28

    Graphical abstract: Preparing and activating process of nitrogen-doped hierarchical porous carbon (NHPC). - Highlights: • The well-defined PAN-b-PMMA copolymer was synthesized by atom transfer radical polymerization with narrow molecular weight distribution. • Nitrogen-doped hierarchical porous structure (NHPC) was prepared through a simple carbonization procedure of PAN-b-PMMA precursor. • NHPC possessed hierarchical porous structure with high BET surface area of 257 m{sup 2} g{sup −1} and DFT mesopore size of 14.61 nm. • Effects of activation conditions on supercapacitive behavior were systematically studied. - Abstract: The nitrogen-doped hierarchical porous carbon (NHPC) material was successfully prepared through a simple carbonization procedure of well-defined diblock copolymer precursor containing nitrogen-enriched carbon source, i.e., polyacrylonitrile (PAN), and asacrificial block, i.e., polymethylmethacrylate (PMMA). PAN-b-PMMA diblock copolymer was synthesized by atom transfer radical polymeriation (ATRP) with narrow molecular weight distribution. The as-obtained NHPC possessed nitrogen-doped hierarchical porous structure with high BET surface area of 257 m{sup 2} g{sup −1} and Nonlocal density functional theory (NLDFT) mesopore size of 14.61 nm. Surface activated nitrogen-doped hierarchical porous carbon (A-NHPC) materials were obtained by subsequent surface activation with HNO{sub 3} solution. The effects of activation conditions on supercapacitive behavior were systematically studied, a maximum specific capacitance of 314 F g{sup −1} at a current density of 0.5 A g{sup −1} was achieved in 2 M KOH aqueous electrolyte. Simultaneously, it exhibited excellent rate capability of 67.8% capacitance retention as the current density increased from 0.5 to 20 A g{sup −1} and superior cycling performance of 90% capacitance retention after 10,000 cycles at the current density of 2 A g{sup −1}.

  7. Preparation and characterization of (10)B boric acid with high purity for nuclear industry.

    Science.gov (United States)

    Zhang, Weijiang; Liu, Tianyu; Xu, Jiao

    2016-01-01

    Boric acid is often added into coolant as neutron capture agent for pressurized water reactor, whose amount is influenced by its abundance and purity. Therefore, the preparation of enriched (10)B boric acid with high purity is beneficial to nuclear industry. (10)B is also used in developing tumor-specific boronated drugs in boron neutron capture therapy. The boronated drug can be administered to patient intravenously, intratumorally, or deposited at tumor site in surgical excision. Thus, enriched (10)B boric acid is of practical significance in the field of medicine. Self-made boron trifluoride-methanol-complex solution was selected as one of the experimental reagents, and the preparation of (10)B acid was realized by one-step reaction for the complexes with water and calcium chloride. The determination of electrical conductivity in reaction process proves that the optimum reaction time was 16-20 h. Furthermore, the effect of reaction time, ratio of calcium chloride to complex as well as the amount of water on the purity and yield of boric acid was investigated. Finally, the optimum reaction time was 20 h, the optimal solid-liquid ratio (molar ratio) was 3:1, and the amount of water was 1 L of deionized water for each mol of the complex. H2O2 was added in the reaction process to remove Fe(2+). After recrystallization, IR spectra of (10)B boric acid was measured and compared with standard to verify the product of boric acid. The feasibility of the preparation method was determined by the detection of XRD of boric acid. To observe the morphology by polarizing microscope, crystal structure was obtained. The purity of the final product is 99.95 %, and the yield is 96.47 %. The ion concentration of boric acid accords with the national standard of high purity, which was determined by ICP.

  8. Miniaturized, High Flow, Low Dead Volume Preconcentrator for Trace Contaminants in Water under Microgravity Conditions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Thorleaf Research, Inc. has demonstrated feasibility in Phase I and now proposes a Phase II effort to develop a miniaturized high flow, low dead-volume...

  9. Preparative separation of high-purity cordycepin from Cordyceps militaris(L.) Link by high-speed countercurrent chromatography

    Science.gov (United States)

    Zhu, Licai; Liang, Yong; Lao, Deqiang; Zhang, Tianyou; Ito, Yoichiro

    2009-01-01

    A high-speed counter-current chromatography (HSCCC) technique in a preparative scale has been applied to separate and purify cordycepin from the extract of Cordyceps militaris(L.) Link by a one-step separation. A high efficiency of HSCCC separation was achieved on a two-phase solvent system of n-hexane–n-butanol–methanol–water (23:80:30:155, v/v/v/v) by eluting the lower mobile phase at a flow rate of 2 ml/min under a revolution speed of 850 rpm. HSCCC separation of 216.2 mg crude sample (contained cordycepin at 44.7% purity after 732 cation-exchange resin clean-up) yielded 64.8 mg cordycepin with purity of 98.9% and 91.7% recovery. Identification of the target compound was performed by UV, IR, MS, 1H NMR and 13C NMR. PMID:21643461

  10. Module-assisted preparation of {sup 64}Cu with high specific activity

    Energy Technology Data Exchange (ETDEWEB)

    Thieme, S. [Institute of Radiopharmacy, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510 119, 01314 Dresden (Germany); Walther, M., E-mail: m.walther@hzdr.de [Institute of Radiopharmacy, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510 119, 01314 Dresden (Germany); Pietzsch, H.-J. [Institute of Radiopharmacy, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510 119, 01314 Dresden (Germany); Henniger, J. [Institute of Nuclear and Particle Physics, University of Technology Dresden, 01062 Dresden (Germany); Preusche, S.; Maeding, P.; Steinbach, J. [Institute of Radiopharmacy, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510 119, 01314 Dresden (Germany)

    2012-04-15

    In this work the production of {sup 64}Cu via the {sup 64}Ni(p,n){sup 64}Cu reaction with optimized conditions for low current irradiation is presented. Different target setups and cleaning steps for lowering metal contaminations in the product were applied. {sup 64}Cu with high specific activities up to 1685 GBq/{mu}mol was produced despite low overall activity ({approx}4.2 GBq per run). The module processing leads to a highly reproducible, reliable product quality (<1 {mu}g Cu and <7 {mu}g Ni). Besides its diagnostic value {sup 64}Cu may be of interest even for therapeutic purposes due to its decay characteristics. - Highlights: Black-Right-Pointing-Pointer Theoretical comparison of {sup 64}Cu and {sup 67}Cu for therapeutical use. Black-Right-Pointing-Pointer Evaluation of different target setups. Black-Right-Pointing-Pointer Different specific activity determination methods in comparison. Black-Right-Pointing-Pointer Detailed description of module operation. Black-Right-Pointing-Pointer Optimized {sup 64}Ni recycling and purification.

  11. Molecularly imprinted microspheres prepared by precipitation polymerization at high monomer concentrations

    Directory of Open Access Journals (Sweden)

    Renkecz Tibor

    2014-01-01

    Full Text Available Highly crosslinked polymer microparticles have been prepared by precipitation polymerization using high monomer loadings (≥25 v/v % which generally would lead to bulk monoliths. The microparticle format was achieved by the use of non-solvating diluents either alone or in combination with co-solvents. Two distinct morphologies were observed. Monodisperse smooth microspheres were obtained using a thermodynamically good co-solvent whereas segmented irregular particles were formed with poorer co-solvents. It has been found that during polymerization the forming polymer particles were enriched in the co-solvent and this effect was more pronounced when good co-solvents were used. The type of functional monomer, crosslinker and co-solvent, and the non-solvent/co-solvent ratio were identified as influential parameters on the microparticle morphology. With the proposed methodology molecularly imprinted microparticles have been prepared successfully for three different templates, naproxen, diclofenac and toltrazuril using various functional monomers, crosslinkers and polymerization solvent mixtures.

  12. Antimicrobial brass coatings prepared on poly(ethylene terephthalate) textile by high power impulse magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ying-Hung, E-mail: tieamo2002@gmail.com; Wu, Guo-Wei; He, Ju-Liang

    2015-03-01

    The goal of this work is to prepare antimicrobial, corrosion-resistant and low-cost Cu65Zn35 brass film on poly(ethylene terephthalate) (PET) fabric by high-power impulse magnetron sputtering (HIPIMS), which is known to provide high-density plasma, so as to generate a strongly adherent film at a reduced substrate temperature. The results reveal that the brass film grows in a layer-plus-island mode. Independent of their deposition time, the obtained films retain a Cu/Zn elemental composition ratio of 1.86 and exhibit primarily an α copper phase structure. Oxygen plasma pre-treatment for 1 min before coating can significantly increase film adhesion such that the brass-coated fabric of Grade 5 or Grade 4–5 can ultimately be obtained under dry and wet rubbing tests, respectively. However, a deposition time of 1 min suffices to provide effective antimicrobial properties for both Staphylococcus aureus and Escherichia coli. As a whole, the feasibility of using such advanced HIPIMS coating technique to develop durable antimicrobial textile was demonstrated. - Highlights: • Prepare antimicrobial, corrosion-resistant and low-cost Cu65Zn35 brass film on PET fabric by HIPIMS • Brass-coated fabric with excellent durability, even undergone rubbing and washing tests • Brass-coated fabric provides effective antimicrobial properties for E. coli and S. aureus. • After brass coating, PET fabric still retained its mechanical property.

  13. Construction of sputtering system and preparation of high temperature superconducting thin films

    CERN Document Server

    Kaynak, E

    2000-01-01

    The preparation of high T sub c superconducting thin film is important both for the understanding of fundamental behaviours of these materials and for the investigations on the usefulness of technological applications. High quality thin films can be prepared by various kinds of techniques being used today. Among these, sputtering is the most preferred one. The primary aim of this work is the construction of a r. f. and c. magnetron sputtering system. For this goal, a magnetron sputtering system was designed and constructed having powers up to 500W (r.f.) and 1KW (d.c.) that enables to deposit thin films of various kinds of materials: metals, ceramics and magnetic materials. The temperature dependence of the electrical resistance of the films was investigated by using four-point probe method. The zero resistance and the transition with of the films were measured as 80-85 K, and 2-9 K, respectively. The A.C. susceptibility experiments were done by utilising the system that was designed and constructed. The appl...

  14. High pressure air jet in the endoscopic preparation room: risk of noise exposure on occupational health.

    Science.gov (United States)

    Chiu, King-Wah; Lu, Lung-Sheng; Wu, Cheng-Kun

    2015-01-01

    After high-level disinfection of gastrointestinal endoscopes, they are hung to dry in order to prevent residual water droplets impact on patient health. To allow for quick drying and clinical reuse, some endoscopic units use a high pressure air jet (HPAJ) to remove the water droplets on the endoscopes. The purpose of this study was to evaluate the excessive noise exposure with the use of HPAJ in endoscopic preparation room and to investigate the risk to occupational health. Noise assessment was taken during 7 automatic endoscopic reprocessors (AERs) and combined with/without HPAJ use over an 8-hour time-weighted average (TWA). Analytical procedures of the NIOSH and the ISO for noise-induced hearing loss were estimated to develop analytic models. The peak of the noise spectrum of combined HPAJ and 7 AERs was significantly higher than that of the 7 AERs alone (108.3 ± 1.36 versus 69.3 ± 3.93 dBA, P risk of hearing loss (HL > 2.5 dB) was 2.15% at 90 dBA, 11.6% at 95 dBA, and 51.3% at 100 dBA. The odds ratio was 49.1 (95% CI: 11.9 to 203.6). The noise generated by the HPAJ to work over TWA seriously affected the occupational health and safety of those working in an endoscopic preparation room.

  15. High efficient preparation of carbon nanotube-grafted carbon fibers with the improved tensile strength

    Science.gov (United States)

    Fan, Wenxin; Wang, Yanxiang; Wang, Chengguo; Chen, Jiqiang; Wang, Qifen; Yuan, Yan; Niu, Fangxu

    2016-02-01

    An innovative technique has been developed to obtain the uniform catalyst coating on continuously moving carbon fibers. Carbon nanotube (CNT)-grafted carbon fibers with significantly improved tensile strength have been succeeded to produce by using chemical vapor deposition (CVD) when compared to the tensile strength of untreated carbon fibers. The critical requirements for preparation of CNT-grafted carbon fibers with high tensile strength have been found, mainly including (i) the obtainment of uniform coating of catalyst particles with small particle size, (ii) the low catalyst-induced and mechano-chemical degradation of carbon fibers, and (iii) the high catalyst activity which could facilitate the healing and strengthening of carbon fibers during the growth of CNTs. The optimum growth temperature was found to be about 500 °C, and the optimum catalyst is Ni due to its highest activity, there is a pronounced increase of 10% in tensile strength of carbon fibers after CNT growth at 500 °C by using Ni catalyst. Based on the observation from HRTEM images, a healing and crosslink model of neighboring carbon crystals by CNTs has been formulated to reveal the main reason that causes an increase in tensile strength of carbon fibers after the growth of CNTs. Such results have provided the theoretical and experimental foundation for the large-scale preparation of CNT-grafted carbon fibers with the improved tensile strength, significantly promoting the development of CNT-grafted carbon fiber reinforced polymer composites.

  16. Highly porous, low elastic modulus 316L stainless steel scaffold prepared by selective laser melting.

    Science.gov (United States)

    Čapek, Jaroslav; Machová, Markéta; Fousová, Michaela; Kubásek, Jiří; Vojtěch, Dalibor; Fojt, Jaroslav; Jablonská, Eva; Lipov, Jan; Ruml, Tomáš

    2016-12-01

    Recently, porous metallic materials have been extensively studied as candidates for use in the fabrication of scaffolds and augmentations to repair trabecular bone defects, e.g. in surroundings of joint replacements. Fabricating these complex structures by using common approaches (e.g., casting and machining) is very challenging. Therefore, rapid prototyping techniques, such as selective laser melting (SLM), have been investigated for these applications. In this study, we characterized a highly porous (87 vol.%) 316L stainless steel scaffold prepared by SLM. 316L steel was chosen because it presents a biomaterial still widely used for fabrication of joint replacements and, from the practical point of view, use of the same material for fabrication of an augmentation and a joint replacement is beneficial for corrosion prevention. The results are compared to the reported properties of two representative nonporous 316L stainless steels prepared either by SLM or casting and subsequent hot forging. The microstructural and mechanical properties and the surface chemical composition and interaction with the cells were investigated. The studied material exhibited mechanical properties that were similar to those of trabecular bone (compressive modulus of elasticity ~0.15GPa, compressive yield strength ~3MPa) and cytocompatibility after one day that was similar to that of wrought 316L stainless steel, which is a commonly used biomaterial. Based on the obtained results, SLM is a suitable method for the fabrication of porous 316L stainless steel scaffolds with highly porous structures.

  17. Strong and Stable Nanocomposites Prepared by High-Pressure Torsion of Cu-Coated Fe Powders

    Directory of Open Access Journals (Sweden)

    Timo Müller

    2016-09-01

    Full Text Available Segregation and chemical inhomogeneity are well-known problems in powder metallurgy and are also an issue for new applications of powder mixtures, for example as starting materials for severe plastic deformation. In this study, Cu-coated Fe powder was prepared via immersion deposition, inductively hot-pressed and subsequently deformed using high-pressure torsion. The homogeneity of the pressed material was found to be much better than that of powder mixtures that were prepared for comparison. During severe plastic deformation, higher hardness was observed for the coated powder as compared to powder mixtures even after low strains. In the saturation state, the coated powder was found to result in a hardness of about 600 HV, which is significantly harder than for the powder mixtures. This is attributed to the greater amount of impurities introduced by the coating process. It is shown that coated powders are promising starting materials for severe plastic deformation in order to reduce the amount of strain necessary to reach the saturation state and to obtain high strength and more homogeneous mechanical alloying.

  18. High efficiency and low cost preparation of size controlled starch nanoparticles through ultrasonic treatment and precipitation.

    Science.gov (United States)

    Chang, Yanjiao; Yan, Xiaoxia; Wang, Qian; Ren, Lili; Tong, Jin; Zhou, Jiang

    2017-07-15

    The purpose of this work was to develop an approach to produce size controlled starch nanoparticles (SNPs), via precipitation with high efficiency and low cost. High concentration starch aqueous pastes (up to 5wt.%) were treated by ultrasound. Viscosity measurements and size exclusion chromatography characterization revealed that, after 30min ultrasonic treatment, viscosity of the starch pastes decreased two orders of magnitude and the weight average molecular weight of the starch decreased from 8.4×10(7) to 2.7×10(6)g/mol. Dynamic light scattering measurements and scanning electron microscopy observations showed that the SNPs prepared from the starch pastes with ultrasonic treatments were smaller (∼75nm) and more uniform. Moreover, SNPs could be obtained using less non-solvents. X-ray diffraction results indicated that effect of the ultrasonic treatment on crystalline structure of the SNPs was negligible. Ultrasound can be utilized to prepare smaller SNPs through nanoprecipitation with higher efficiency and lower cost. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Preparation and properties of hexagonal boron nitride fibers used as high temperature membrane filter

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xinmei, E-mail: houxinmei@ustb.edu.cn; Yu, Ziyou; Li, Yang; Chou, Kuo-Chih

    2014-01-01

    Graphical abstract: - Highlights: • h-BN fibers were successfully fabricated using H{sub 3}BO{sub 3} and C{sub 3}H{sub 6}N{sub 6} as raw materials. • The obtained BN fibers were polycrystalline and uniform in morphology. • It exhibited good oxidation resistance and low thermal expansion coefficient. - Abstract: Hexagonal boron nitride fibers were synthesized via polymeric precursor method using boric acid (H{sub 3}BO{sub 3}) and melamine (C{sub 3}H{sub 6}N{sub 6}) as raw materials. The precursor fibers were synthesized by water bath and BN fibers were prepared from the precursor at 1873 K for 3 h in flowing nitrogen atmosphere. The crystalline phase and microstructures of BN fibers were examined by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and high resolution electron microscopy. The results showed that h-BN fibers with uniform morphology were successfully fabricated. The well-synthesized BN fibers were polycrystalline with 0.4–1.5 μm in diameter and 200–500 μm in length. The as-prepared samples exhibited good oxidation resistance and low thermal expansion coefficient at high temperature.

  20. Highly efficient preparation of lipophilic hydroxycinnamates by solvent-free lipase-catalyzed transesterification.

    Science.gov (United States)

    Weitkamp, Petra; Vosmann, Klaus; Weber, Nikolaus

    2006-09-20

    Various medium- or long-chain alkyl cinnamates and hydroxycinnamates, including oleyl p-coumarate as well as palmityl and oleyl ferulates, were prepared in high yield by lipase-catalyzed transesterification of an equimolar mixture of a short-chain alkyl cinnamate and a fatty alcohol such as lauryl, palmityl, and oleyl alcohol under partial vacuum at moderate temperature in the absence of solvents and drying agents in direct contact with the reaction mixture. Immobilized lipase B from Candida antarctica was the most effective biocatalyst for the various transesterification reactions. Transesterification activity of this enzyme was up to 56-fold higher than esterification activity for the preparation of medium- and long-chain alkyl ferulates. The relative transesterification activities found for C. antarctica lipase were of the following order: hydrocinnamate > cinnamate > 4-hydroxyhydrocinnamate > 3-methoxycinnamate > 2-methoxycinnamate approximately 4-methoxycinnamate approximately 3-hydroxycinnamate > hydrocaffeate approximately 4-hydroxycinnamate > ferulate > 2-hydroxycinnamate > caffeate approximately sinapate. With respect to the position of the hydroxy substituents at the phenyl moiety, the transesterification activity of C. antarctica lipase B increased in the order meta > para > ortho. The immobilized lipases from Rhizomucor miehei and Thermomyces lanuginosus demonstrated moderate and low transesterification activity, respectively. Compounds with inverse chemical structure, that is, 3-phenylpropyl alkanoates such as 3-(4-hydroxyphenyl)propyl oleate and 3-(3,4-dimethoxyphenyl)propyl oleate, were obtained by C. antarctica lipase-catalyzed transesterification of fatty acid methyl esters with the corresponding 3-phenylpropan-1-ols in high yield, as well.

  1. Preparation of lithium ferrite nanoparticles by high energy ball milling and characterizations

    Directory of Open Access Journals (Sweden)

    J. Touthang

    2016-11-01

    Full Text Available Ferrites are ferrimagnetic ceramic materials with inherent useful electromagnetic properties. Of them, spinelstructured ferrites are promising materials for microwave device applications; stress/torsion sensors and energy storage applications like anode materials in lithium batteries, fuel cells, solar cells etc. Nanostructured spinels further have high and wide scope of potential applications. In the present study, two different types of varied sized ferrimagnetic lithium ferrite spinel nanoparticles prepared using chemical sol-gel auto-combustion method were chosen. The prepared spinel particles were heated at 300°C for 1h. After heating the powders were milled using a High Energy Ball Mill for 30 minutes to further grind the particles and then subjected to various characterizations. Structural characterization was done using X-Ray Diffraction Method (XRD. The study revealed the spinel structure of these samples. Structural parameter such as lattice constant was determined using XRD data and found that the lattice parameter agrees with the standard data. DLS study found the agglomerations of the nanoparticles. The synthesized nanospinel particles were also characterized by the UVVis Spectroscopy, the Fourier Transform Infrared Spectroscopy (FTIR. Finally the magnetic hysteresis properties were studied using a Vibrating Sample Magnetometer (VSM.

  2. Facile preparation of graphene by high-temperature electrolysis and its application in supercapacitor.

    Science.gov (United States)

    Jiao, Chen-Xu; Xing, Bao-Yan; Zhao, Jian-Guo; Geng, Yu; Li, Zuo-Peng

    2014-01-01

    Graphene is well known owing to its astonishing properties: stronger than diamond, more conductive than copper and more flexible than rubber. Because of its potential uses in industry, researchers have been searching for less toxicity ways to make graphene in large amount with lower cost. We demonstrated an efficient method to prepare graphene by high temperature electrolysis technique. High resolution scanning electron microscopy and raman spectroscopy were used to characterize the microstructure of graphene. Graphene was assembled into the supercapacitor and its performance of electrochemical capacitor was investigated by constant current charge and discharge, cyclic voltammetry and AC impedance. The results showed that the micro-morphology of the prepared graphene was multilayer and it was favorable when the electrolytic voltage was 1.5 V. When the current density is 1 mA/cm(2), the specific capacitance of the graphene supercapacitor can reach 78.01 F/g in 6 mol/L KOH electrolyte, which was an increase of 114% compared with 36.43 F/g of conventional KOH electrolyte.

  3. Solvent-Assisted Preparation of High-Performance Mesoporous CH₃NH₃Pbl₃ Perovskite Solar Cells.

    Science.gov (United States)

    Li, Zhi-Hua; Liu, Jie; Ma, Jing-Yuan; Jiang, Yan; Ge, Qian-Qing; Ding, Jie; Hu, Jin-Song; Wan, Li-Jun

    2016-01-01

    Organometal trihalide perovskite based solar cells have attracted great attention worldwide since their power conversion efficiency (PCE) have risen to over 15% within only 3 years of development. Comparing with other types of perovskite solar cells, mesostructured perovskite solar cells based on CH₃NH₃Pbl₃ as light harvesting material have already demonstrated remarkable advance in performance and reproducibility. Here, we reported a mesoscopic TiO₂/CH₃NH₃Pbl₃ heterojunction solar cell with uniform perovskite thin film prepared via solvent-assisted solution processing method. The best performing device delivered photocurrent density of 20.11 mA cm⁻², open-circuit voltage of 1.02 V, and fill factor of 0.70, leading to a PCE of 14.41%. A small anomalous hysteresis in the J-V curves was observed, where the PCE at forward scan was measured to be 84% of the PCE at reverse scan. Based on a statistical analysis, the perovskite solar cells prepared by the reported method exhibited reproducible and high PCE, indicating its promising application in the fabrication of low-cost and high-efficiency perovskite solar cells.

  4. DIFFERENCES IN THE PREPARATION OF STUDENT LEARNING OUTCOMES OF HIGH AND LOW IN DEALING WITH NATIONAL EXAM

    Directory of Open Access Journals (Sweden)

    Linda Fitria

    2016-06-01

    Full Text Available To pass the examination, the most important thing to be considered by the students is the examination preparation. There are so many kinds of examination faced by the students, one of it is national examination. Therefore, the national examination should be prepared well by the students, school, and parents since it is a tool to measure students competency of achievement which held by education unit in order to obtain learning confession and it is a requirement of finishing education level. This research is aimed to describe and differentiate the preparation of students with high learning achievement and the students with low learning achievement in facing national examination. This is a comparative quantitative descriptive approach supported with interview. The target of the research is students of SMA Adabiah Padang, with 327 students as the population. There are 80 students placed as sample. The research finding reveals that (1 physical preparation of students with high learning achievement and the students with low learning achievement in facing national examination is in well prepared category (2 psychology preparation for both students with high learning achievement and the students with low learning achievement is in well prepared category, (3 the preparation in mastering the learning material for both students with high learning achievement and the students with low learning achievement is in well prepared category,(4 the analysis of t test result reveals that there is a significant difference between students with high learning achievement and the students with low learning achievement of SMA Adabiah Padang.Keywords: Preparation National Examination, Students Learning Achievement.

  5. Mantle mixing and crustal contamination as the origin of the high-Sr radiogenic magmatism of Stromboli (Aeolian arc)

    Science.gov (United States)

    Luais, Béatrice

    1988-04-01

    The temporal evolution of the volcanic activity on Stromboli (Aeolian arc) is characterized by high-K calc-alkaline magmatism followed by shoshonitic magmatism. Rocks from the two series can be distinguished by their K and P concentrations, hygromagmaphile element concentrations, and Sr isotopic ratios, which are higher in the shoshonitic series than in high-K calc-alkaline series. The mantle oxygen isotopic ratios of the shoshonitic series (Javoy, 1976 [39]) suggest that these characteristics are generated in the upper mantle. The geochemical and isotopic characteristics of the magmatism on Stromboli are midway between those of calc-alkaline rocks from the Aeolian arc and potassic rocks from Central Italy (Campanian region). The similarity between the most radiogenic and LILE-enriched samples of the shoshonitic series and the low-K magmatism in Central Italy suggests that the volcanism on Stromboli is the result of mantle mixing between a calc-alkaline magma and a radiogenic Sr/hygromagmaphile element-enriched magma, such as the high-K magmatism in Central Italy (Alban Hills). The chemical and isotopic characteristics of the differentiated samples can be explained by crustal contamination during the differentiation of the basic liquid by fractional crystallization. An anorthose-bearing xenolith with high Sr isotopic composition of crustal origin (0.71300) is a likely candidate for this crustal component.

  6. Mantle mixing and crustal contamination as the origin of the high-Sr radiogenic magmatism of Stromboli (Aeolian arc)

    Energy Technology Data Exchange (ETDEWEB)

    Luais, B.

    1988-04-01

    The temporal evolution of the volcanic activity on Stromboli (Aeolian arc) is characterized by high-K calc-alkaline magmatism followed by shoshonitic magmatism. Rocks from the two series can be distinguished by their K and P concentrations, hygromagmaphile element concentrations, and Sr isotopic ratios, which are higher in the shoshonitic series than in high-K calc-alkaline series. The mantle oxygen isotopic ratios of the shoshonitic series suggest that these characteristics are generated in the upper mantle. The geometrical and isotopic characteristics of the magmatism on Stromboli are midway between those of calc-alkaline rocks from the Aeolian arc and potassic rocks from Central Italy (Campanian region). The similarity between the most radiogenic and LILE-enriched samples of the shoshonitic series and the low-K magmatism in Central Italy suggests that the volcanism on Stromboli is the result of mantle mixing between a calc-alkaline magma and a radiogenic Sr/hygromagmaphile element-enriched magma, such as the high-K magmatism in Central Italy (Alban Hills). The chemical and isotopic characteristics of the differentiated samples can be explained by crustal contamination during the differentiation of the basic liquid by fractional crystallization. An anorthose-bearing xenolith with high Sr isotopic composition of crustal origin (0.71300) is a likely candidate for thus crustal component.

  7. One-step preparation of nitrogen-doped graphene nanosheets for high-performance supercapacitors

    Science.gov (United States)

    Gao, Biaofeng; Zhou, Haitao; Yang, Jianhong

    2017-07-01

    Graphene nanosheets (GNs) have been successfully synthesized by one-step carbonization and simultaneous chemical activation of polyaniline (PANI) nanofibers, with large surface area (1759.5 m2 g-1), high pore volume (1.16 cm3 g-1) and a mesopore rich structure (volume in micropore/total ratio, 2.16%). The vital (NDs) become entrapped within a carbon lattice (to form GNs). GNs could be used as an outstanding electrode material for supercapacitors in EMIMBF4 with high cycling stability (more than 73% retention of the initial capacitance after 10,000 cycles). The symmetric supercapacitor has an excellent energy density of 170.2 Wh kg-1 (25 °C) at 0.5 A g-1, with an operating cell voltage of 4.0 V. Meanwhile, oriented activation with polymers of anisotropic geometry might be regarded as a novel process to prepare GNs.

  8. Preparation and Adsorption Performances of Phragmites australis Activated Carbon with High Acidity

    Directory of Open Access Journals (Sweden)

    FU Cheng-kai

    2017-03-01

    Full Text Available For removal of heavy metals from wastewater and recycling the wetland plants, the present study investigated the viability of using silage of Phragmites australis (PA to prepare activated carbons (ACs with high acidity. BET surface area, porous texture and surface functional characteristics of ACs were analyzed by N2 adsorption/desorption, elemental analysis and Boehm titration method. ACs presented well-developed micro-porosity and favorable surface acidity. The sorption equilibrium data for Ni (Ⅱ and Cd (Ⅱ sorption onto ACs were analyzed by the Langmuir and Freundlich models. The Langmuir model was fitted well to the adsorption behavior. The properties of high surface acidity promoted the adsorption of heavy metals by the silage-treated ACs and the chemical sorption played the key role in the sorption process.

  9. Preparation of Hard Coating Films with High Refractive Index from Titania Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nam Woo; Ahn, Chi Yong; Song, Ki Chang [Konyang University, 121 Daehak-ro, Nonsan (Korea, Republic of)

    2015-12-15

    The titania (TiO{sub 2}) nanoparticles with a diameter 2-3 nm were synthesized by controlling hydrolysis of titanium tetraisopropoxide (TTIP) in acid solution. Organic-inorganic hybrid coating solutions were prepared by reacting the titania nanoparticles with 3-glycidoxypropyl trimethoxysilane (GPTMS) by the sol-gel method. The hard coating films with high refractive index were obtained by curing thermally at 120 .deg. C after spin-coating the coating solutions on the polycarbonate (PC) sheets. The coating films showed high optical transparency of 90% in the visible range and exhibited a pencil hardness of 2H. Also, the refractive index at 633 nm wavelength of coating films enhanced from 1.502 to 1.584 as the weight content of titania nanoparticles in the coating solutions increased from 4% to 25%.

  10. High quality antireflective ZnS thin films prepared by chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Tec-Yam, S.; Rojas, J.; Rejon, V. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Merida, Departamento de Fisica Aplicada, Km. 6 Antigua Carretera a Progreso, AP 73-Cordemex, 97310 Merida Yucatan (Mexico); Oliva, A.I., E-mail: oliva@mda.cinvestav.mx [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Merida, Departamento de Fisica Aplicada, Km. 6 Antigua Carretera a Progreso, AP 73-Cordemex, 97310 Merida Yucatan (Mexico)

    2012-10-15

    Zinc sulfide (ZnS) thin films for antireflective applications were deposited on glass substrates by chemical bath deposition (CBD). Chemical analysis of the soluble species permits to predict the optimal pH conditions to obtain high quality ZnS films. For the CBD, the ZnCl{sub 2}, NH{sub 4}NO{sub 3}, and CS(NH{sub 2}){sub 2} were fixed components, whereas the KOH concentration was varied from 0.8 to 1.4 M. Groups of samples with deposition times from 60 to 120 min were prepared in a bath with magnetic agitation and heated at 90 Degree-Sign C. ZnS films obtained from optimal KOH concentrations of 0.9 M and 1.0 M exhibited high transparency, homogeneity, adherence, and crystalline. The ZnS films presented a band gap energy of 3.84 eV, an atomic Zn:S stoichiometry ratio of 49:51, a transmittance above 85% in the 300-800 nm wavelength range, and a reflectance below 25% in the UV-Vis range. X-ray diffraction analysis revealed a cubic structure in the (111) orientation for the films. The thickness of the films was tuned between 60 nm and 135 nm by controlling the deposition time and KOH concentration. The incorporation of the CBD-ZnS films into ITO/ZnS/CdS/CdTe and glass/Mo/ZnS heterostructures as antireflective layer confirms their high optical quality. -- Highlights: Black-Right-Pointing-Pointer High quality ZnS thin films were prepared by chemical bath deposition (CBD). Black-Right-Pointing-Pointer Better CBD-ZnS films were achieved by using 0.9 M-KOH concentration. Black-Right-Pointing-Pointer Reduction in the reflectance was obtained for ZnS films used as buffer layers.

  11. Preparation optimization and spectral properties of BCNO phosphors with high quantum efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Chunrong; Zhang, Xinghua, E-mail: xinghua146@126.com; Zhou, Liyu; Lu, Zunming; Lin, Jing; Xu, Xuewen; Li, Lanlan; Zhang, Xiao; Xue, Yanming; Meng, Fanbin; Zhao, Jianling; Tang, Chengchun, E-mail: tangcc@hebut.edu.cn

    2014-09-15

    BCNO phosphors with high quantum efficiency (QE) were synthesized using trimethyl borate, melamine and urotropine as raw materials. The effects of urotropine, starting materials ratio, sintering time and temperature on luminescence properties were systematically investigated and the preparation conditions were optimized. The BCNO phosphor has turbostratic boron nitride structure and its size in the range of several millimeters. The emission peak position was not influenced by the content of urotropine. However, the emission peak blue can be tuned from 475 nm to 535 nm with increasing B/N source ratios (R{sub B/N}=2–6), while the QE decreased from 65.2% to 15.8%. The emission peaks of BCNO phosphor with R{sub B/N}=4 were in the range of green light (495–540 nm) with high QE (20.8–51.4%) as sintering time increased (4–20 h). In addition, the emission peaks of BCNO phosphor with R{sub B/N}=4 blue-shifted from 525 nm to 460 nm and increased QE (16.1–56.7%) with increasing sintering temperature (650–750 °C). The formation mechanism of BCNO phosphors was investigated by means of ultraviolet visible absorption spectra and infrared spectra. The tunable emission spectra and high QE corresponded to the chemical composition, carbon concentration and crystallinity of BCNO phosphors. - Highlights: • We prepared BCNO phosphors with high quantum efficiency (65.2%). • The effects of raw materials, sintering condition on spectral properties were investigated. • The formation and luminescence mechanism of BCNO phosphors were investigated.

  12. An in situ method for the high resolution mapping of (137)Cs and estimation of vertical depth penetration in a highly contaminated environment.

    Science.gov (United States)

    Varley, Adam; Tyler, Andrew; Dowdall, Mark; Bondar, Yuri; Zabrotski, Viachaslau

    2017-12-15

    The Chernobyl nuclear power plant meltdown has to date been the single largest release of radioactivity into the environment. As a result, radioactive contamination that poses a significant threat to human health still persists across much of Europe with the highest concentrations associated with Belarus, Ukraine, and western Russia. Of the radionuclides still prevalent with these territories (137)Cs presents one of the most problematic remediation challenges. Principally, this is due to the localised spatial and vertical heterogeneity of contamination within the soil (~10's of meters), thus making it difficult to accurately characterise through conventional measurement techniques such as static in situ gamma-ray spectrometry or soil cores. Here, a practical solution has been explored, which utilises a large number of short-count time spectral measurements made using relatively inexpensive, lightweight, scintillators (sodium iodide and lanthanum bromide). This approach offers the added advantage of being able to estimate activity and burial depth of (137)Cs contamination in much higher spatial resolution compared to traditional approaches. During the course of this work, detectors were calibrated using the Monte Carlo Simulations and depth distribution was estimated using the peak-to-valley ratio. Activity and depth estimates were then compared to five reference sites characterised using soil cores. Estimates were in good agreement with the reference sites, differences of ~25% and ~50% in total inventory were found for the three higher and two lower activity sites, respectively. It was concluded that slightly longer count times would be required for the lower activity (<1MBqm(-2)) sites. Modelling and reference site results suggest little advantage would be gained through the use of the substantially more expensive lanthanum bromide detector over the sodium iodide detector. Finally, the potential of the approach was demonstrated by mapping one of the sites and its

  13. Mathematical Preparation versus Career Aspirations: Sex-Related Differences among College-Bound Wyoming High School Seniors.

    Science.gov (United States)

    Olson, Melfried; Kansky, Bob

    1981-01-01

    A statewide sampling of Wyoming's graduating senior-high pupils raised serious concerns regarding the preparation of many of these pupils for college mathematics courses. Future occupational choices available to most females were seen as severely limited. (MP)

  14. Comparison of oxalate contents and recovery from two green juices prepared using a masticating juicer or a high speed blender

    Directory of Open Access Journals (Sweden)

    Leo Vanhanen

    2015-06-01

    Conclusion: Green juices prepared using common vegetables can contain high levels of soluble oxalates, which will vary with the type and proportion of vegetables used and whether or not the pulp fraction was retained during processing.

  15. Bacterial contamination of traditional ice creams in Kermanshah in 2008

    Directory of Open Access Journals (Sweden)

    Sina Emami

    2013-09-01

    Full Text Available Background: Ice cream is a dairy product that is very popular during warm seasons. Ice cream can be contaminated with various microorganisms including pathogenic bacteria if hygienic procedures are not followed during preparation, distribution and preservation processes. This may put the health of people using ice cream at risk. Our study aimed to examine the bacterial contamination of traditional ice creams in Kermanshah city during 2008. Methods: During summer 2008, 80 samples of traditional ice creams were collected. The samples were examined according to the Iranian National Standard protocols for E. coli, Coliforms,  Salmonella,  Staphylococcus aureus and complete count of microorganisms. Results: Overall, 62 (77.5% samples had microbial contaminations more than the standard limit. Results showed 59 (73.75% and 54 (67.5 % of the samples contained a high number of microorganisms and coliform, respectively. Furthermore 30 (37.5% and 23 (28.75% of the samples were contaminated with E. coli and S. aureus, respectively. However, Salmonella spp. was not found in any of the ice cream samples. Conclusion: The traditional ice creams tested in Kermanshah were heavily contaminated with bacteria. It could be due to the inappropriate preparation and preservation procedures using unpasteurized milk and other materials.  Contaminations may also be induced by personals. So it is recommended to apply the hygienic procedures for preparation and preservation of ice cream including the use of pasteurized milk and other materials.

  16. Quantitative determination of gymnodimine-A by high performance liquid chromatography in contaminated clams from Tunisia coastline.

    Science.gov (United States)

    Marrouchi, Riadh; Dziri, Faten; Belayouni, Nawel; Hamza, Asma; Benoit, Evelyne; Molgó, Jordi; Kharrat, Riadh

    2010-10-01

    Quantitative determination by high performance liquid chromatography (HPLC) was performed for gymnodimine-A (GYM-A), a phycotoxin responsible for the contamination of Tunisian clams. This study demonstrates a rapid and reproducible HPLC-ultraviolet (UV) method for extraction, detection and quantification of GYM-A in toxic clams. The extraction of GYM-A from the digestive gland of clams in acetone, subsequent clean-up with diethyl ether and extraction with dichloromethane is the more valid protocol. Chromatography analyses were performed using a gradient of acetonitrile-water (10:90 to 90:10), containing trifluoroacetic acid (0.1%) for 20 min at 1 mL/min rate with a C18 column. Recovery rates exceeded 96%, and limits of detection and quantification were 5 ng/mL and 8 ng/g digestive gland, respectively. Repeatability and reproducibility were tested for various samples containing different levels of GYM-A. A significant correlation was observed between toxicity level of samples and the determined amount of GYM-A. Also, the persistence of GYM-A in contaminated clams from Boughrara lagoon was demonstrated. The kinetics discharge study of GYM-A in controlled medium, during 1 month, showed that the process of depuration was biphasic with an exponential discharge of 75% of the total amount of sequestered GYM-A during the first 12 days followed by a slow discharge (>10%) for the subsequent days up to the seventeenth day. This is the first time that a quantitative study of GYM-A in clams from Tunisian coasts is performed through the development of a new method for detection and quantify of this phycotoxin. We found HPLC-UV a reliable and suitable alternative to the mouse bioassay.

  17. Bench-scale optimization of bioaugmentation strategies for treatment of soils contaminated with high molecular weight polyaromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Straube, W.l.; Jones-Meehan, J.; Pritchard, P.H.; Jones, W.R. [University of Maryland Biotechnology Institute, Baltimore, MD (United States). Center of Marine Biotechnology

    1999-07-01

    The chemical composition of crude oil, creosote, and refined petroleum includes hundreds of different alkanes and aromatic hydrocarbons, among which are the carcinogenic polycyclic aromatic hydrocarbons (PAHs). Some compounds in hydrocarbon-contaminated soils are rapidly removed by the activities of autochthonous bacterial populations while other PAHs, especially those with four or more fused aromatic rings, are refractory to biodegradation. The persistence of high molecular weight of polyaromatic hydrocarbons (hPAHs) in soils implies either that their low solubility renders them poorly available to bacteria, or that autochthonous bacteria do not contain the metabolic or co-metabolic pathways required for their degradation or both. The rate and extent of PAH degradation in contaminated soil is not always predictable for standard biological treatment strategies. This study examines a matrix of treatments suitable for land farming in order to identify those that maximize the removal of hPAHs. The treatments include those intended to increase the bioavailability of hPAH, such as additions of biosurfactant-producing bacteria (i.e. Pseudomonas aeruginosa No. 64) and addition of light oils, as well as treatments intended to increase the metabolic potential of the bacterial community. The latter includes the addition of inorganic nutrients and bacterial strains capable of degrading hPAHs co-metabolically (i.e. Sphingomonas paucimobilis EPA 505). The efficacy of immobilizing PAH-degrading bacteria on vermiculite is also considered, as will be the monitoring of leachate for biodegradation of PAHs in a simulated land farming operation. 17 refs., 4 figs.

  18. Can field portable X-ray fluorescence (pXRF) produce high quality data for application in environmental contamination research?

    Science.gov (United States)

    Rouillon, Marek; Taylor, Mark P

    2016-07-01

    This research evaluates the analytical capabilities of a field portable X-ray fluorescence spectrometer (pXRF) for the measurement of contaminated soil samples using a matrix-matched calibration. The calibrated pXRF generated exceptional data quality from the measurement of ten soil reference materials. Elemental recoveries improved for all 11 elements post-calibration with reduced measurement variation and detection limits in most cases. Measurement repeatability of reference values ranged between 0.2 and 10% relative standard deviation, while the majority (82%) of reference recoveries were between 90 and 110%. Definitive data quality, the highest of the US EPA's three level quality ranking, was achieved for 15 of 19 elemental datasets. Measurement comparability against inductively coupled plasma atomic emission spectrometry (ICP-AES) values was excellent for most elements (e.g, r(2) 0.999 for Mn and Pb, r(2) > 0.995 for Cu, Zn and Cd). Parallel measurement of reference materials revealed ICP-AES and ICP-MS measured Ti and Cr poorly when compared to pXRF. Individual recoveries of soil reference materials by both ICP-AES and pXRF showed that pXRF was equivalent to or better than ICP-AES values for all but two elements (Ni, As). This study demonstrates pXRF as a suitable alternative to ICP-AES analysis in the measurement of Ti, Cr, Mn, Fe, Cu, Zn, Sr, Cd, and Pb in metal-contaminated soils. Where funds are limited, pXRF provides a low-cost, high quality solution to increasing sample density for a more complete geochemical investigation.

  19. Accuracy assessment of high frequency 3D ultrasound for digital impression-taking of prepared teeth

    Science.gov (United States)

    Heger, Stefan; Vollborn, Thorsten; Tinschert, Joachim; Wolfart, Stefan; Radermacher, Klaus

    2013-03-01

    Silicone based impression-taking of prepared teeth followed by plaster casting is well-established but potentially less reliable, error-prone and inefficient, particularly in combination with emerging techniques like computer aided design and manufacturing (CAD/CAM) of dental prosthesis. Intra-oral optical scanners for digital impression-taking have been introduced but until now some drawbacks still exist. Because optical waves can hardly penetrate liquids or soft-tissues, sub-gingival preparations still need to be uncovered invasively prior to scanning. High frequency ultrasound (HFUS) based micro-scanning has been recently investigated as an alternative to optical intra-oral scanning. Ultrasound is less sensitive against oral fluids and in principal able to penetrate gingiva without invasively exposing of sub-gingival preparations. Nevertheless, spatial resolution as well as digitization accuracy of an ultrasound based micro-scanning system remains a critical parameter because the ultrasound wavelength in water-like media such as gingiva is typically smaller than that of optical waves. In this contribution, the in-vitro accuracy of ultrasound based micro-scanning for tooth geometry reconstruction is being investigated and compared to its extra-oral optical counterpart. In order to increase the spatial resolution of the system, 2nd harmonic frequencies from a mechanically driven focused single element transducer were separated and corresponding 3D surface models were calculated for both fundamentals and 2nd harmonics. Measurements on phantoms, model teeth and human teeth were carried out for evaluation of spatial resolution and surface detection accuracy. Comparison of optical and ultrasound digital impression taking indicate that, in terms of accuracy, ultrasound based tooth digitization can be an alternative for optical impression-taking.

  20. Preparation of Inactivated Human Skin Using High Hydrostatic Pressurization for Full-Thickness Skin Reconstruction.

    Directory of Open Access Journals (Sweden)

    Pham Hieu Liem

    Full Text Available We have reported that high-hydrostatic-pressure (HHP technology is safe and useful for producing various kinds of decellularized tissue. However, the preparation of decellularized or inactivated skin using HHP has not been reported. The objective of this study was thus to prepare inactivated skin from human skin using HHP, and to explore the appropriate conditions of pressurization to inactivate skin that can be used for skin reconstruction. Human skin samples of 8 mm in diameter were packed in bags filled with normal saline solution (NSS or distilled water (DW, and then pressurized at 0, 100, 150, 200 and 1000 MPa for 10 minutes. The viability of skin after HHP was evaluated using WST-8 assay. Outgrowth cells from pressurized skin and the viability of pressurized skin after cultivation for 14 days were also evaluated. The pressurized skin was subjected to histological evaluation using hematoxylin and eosin staining, scanning electron microscopy (SEM, immunohistochemical staining of type IV collagen for the basement membrane of epidermis and capillaries, and immunohistochemical staining of von Willebrand factor (vWF for capillaries. Then, human cultured epidermis (CE was applied on the pressurized skin and implanted into the subcutis of nude mice; specimens were subsequently obtained 14 days after implantation. Skin samples pressurized at more than 200 MPa were inactivated in both NSS and DW. The basement membrane and capillaries remained intact in all groups according to histological and immunohistological evaluations, and collagen fibers showed no apparent damage by SEM. CE took on skin pressurized at 150 and 200 MPa after implantation, whereas it did not take on skin pressurized at 1000 MPa. These results indicate that human skin could be inactivated after pressurization at more than 200 MPa, but skin pressurized at 1000 MPa had some damage to the dermis that prevented the taking of CE. Therefore, pressurization at 200 MPa is optimal for

  1. Mixtures of endocrine disrupting contaminants modelled on human high end exposures

    DEFF Research Database (Denmark)

    Christiansen, Sofie; Kortenkamp, A.; Petersen, Marta Axelstad

    2012-01-01

    in vivo endocrine disrupting effects and information about human exposures was available, including phthalates, pesticides, UV‐filters, bisphenol A, parabens and the drug paracetamol. The mixture ratio was chosen to reflect high end human intakes. To make decisions about the dose levels for studies...... though each individual chemical is present at low, ineffective doses, but the effects of mixtures modelled based on human intakes have not previously been investigated. To address this issue for the first time, we selected 13 chemicals for a developmental mixture toxicity study in rats where data about...... in the rat, we employed the point of departure index (PODI) approach, which sums up ratios between estimated exposure levels and no‐observed‐adverse‐effect‐level (NOAEL) values of individual substances. For high end human exposures to the 13 selected chemicals, we calculated a PODI of 0.016. As only a PODI...

  2. Antimicrobial activity of filamentous fungi isolated from highly antibiotic-contaminated river sediment

    OpenAIRE

    2012-01-01

    Background: Filamentous fungi are well known for their production of substances with antimicrobial activities, several of which have formed the basis for the development of new clinically important antimicrobial agents. Recently, environments polluted with extraordinarily high levels of antibiotics have been documented, leading to strong selection pressure on local sentinel bacterial communities. In such microbial ecosystems, where multidrug-resistant bacteria are likely to thrive, it is poss...

  3. High metal reactivity and environmental risks at a site contaminated by glass waste.

    Science.gov (United States)

    Augustsson, A; Åström, M; Bergbäck, B; Elert, M; Höglund, L O; Kleja, D B

    2016-07-01

    This study addresses the reactivity and risks of metals (Ba, Cd, Co, Cr, Cu, Ni, Pb, Zn, As and Sb) at a Swedish site with large glass waste deposits. Old glassworks sites typically have high total metal concentrations, but as the metals are mainly bound within the glass waste and considered relatively inert, environmental investigations at these kinds of sites are limited. In this study, soil and landfill samples were subjected to a sequential chemical extraction procedure. Data from batch leaching tests and groundwater upstream and downstream of the waste deposits were also interpreted. The sequential extraction revealed that metals in metals are released from pristine glass and subsequently largely retained in the surrounding soil and/or on secondary mineral coatings on fine glass particles. From the approximately 12,000 m(3) of coarse glass waste at the site, almost 4000 kg of Pb is estimated to have been lost through corrosion, which, however, corresponds to only a small portion of the total amount of Pb in the waste. Metal sorption within the waste deposits or in underlying soil layers is supported by fairly low metal concentrations in groundwater. However, elevated concentrations in downstream groundwater and in leachates of batch leaching tests were observed for several metals, indicating on-going leaching. Taken together, the high metal concentrations in geochemically active forms and the high amounts of as yet uncorroded metal-rich glass, indicate considerable risks to human health and the environment.

  4. Three-Dimensional Vibration Isolator for Suppressing High-Frequency Responses for Sage III Contamination Monitoring Package (CMP)

    Science.gov (United States)

    Li, Y.; Cutright, S.; Dyke, R.; Templeton, J.; Gasbarre, J.; Novak, F.

    2015-01-01

    The Stratospheric Aerosol and Gas Experiment (SAGE) III - International Space Station (ISS) instrument will be used to study ozone, providing global, long-term measurements of key components of the Earth's atmosphere for the continued health of Earth and its inhabitants. SAGE III is launched into orbit in an inverted configuration on SpaceX;s Falcon 9 launch vehicle. As one of its four supporting elements, a Contamination Monitoring Package (CMP) mounted to the top panel of the Interface Adapter Module (IAM) box experiences high-frequency response due to structural coupling between the two structures during the SpaceX launch. These vibrations, which were initially observed in the IAM Engineering Development Unit (EDU) test and later verified through finite element analysis (FEA) for the SpaceX launch loads, may damage the internal electronic cards and the Thermoelectric Quartz Crystal Microbalance (TQCM) sensors mounted on the CMP. Three-dimensional (3D) vibration isolators were required to be inserted between the CMP and IAM interface in order to attenuate the high frequency vibrations without resulting in any major changes to the existing system. Wire rope isolators were proposed as the isolation system between the CMP and IAM due to the low impact to design. Most 3D isolation systems are designed for compression and roll, therefore little dynamic data was available for using wire rope isolators in an inverted or tension configuration. From the isolator FEA and test results, it is shown that by using the 3D wire rope isolators, the CMP high-frequency responses have been suppressed by several orders of magnitude over a wide excitation frequency range. Consequently, the TQCM sensor responses are well below their qualification environments. It is indicated that these high-frequency responses due to the typical instrument structural coupling can be significantly suppressed by a vibration passive control using the 3D vibration isolator. Thermal and contamination

  5. High resolution preparation of monocyte-derived macrophages (MDM protein fractions for clinical proteomics

    Directory of Open Access Journals (Sweden)

    Olivieri Oliviero

    2009-02-01

    Full Text Available Abstract Background Macrophages are involved in a number of key physiological processes and complex responses such as inflammatory, immunological, infectious diseases and iron homeostasis. These cells are specialised for iron storage and recycling from senescent erythrocytes so they play a central role in the fine tuning of iron balancing and distribution. The comprehension of the many physiological responses of macrophages implies the study of the related molecular events. To this regard, proteomic analysis, is one of the most powerful tools for the elucidation of the molecular mechanisms, in terms of changes in protein expression levels. Results Our aim was to optimize a protocol for protein fractionation and high resolution mapping using human macrophages for clinical studies. We exploited a fractionation protocol based on the neutral detergent Triton X-114. The 2D maps of the fractions obtained showed high resolution and a good level of purity. Western immunoblotting and mass spectrometry (MS/MS analysis indicated no fraction cross contamination. On 2D-PAGE mini gels (7 × 8 cm we could count more than five hundred protein spots, substantially increasing the resolution and the number of detectable proteins for the macrophage proteome. The fractions were also evaluated, with preliminary experiments, using Surface Enhanced Laser Desorption Ionization Time of Flight Mass Spectrometry (SELDI-TOF-MS. Conclusion This relatively simple method allows deep investigation into macrophages proteomics producing discrete and accurate protein fractions, especially membrane-associated and integral proteins. The adapted protocol seems highly suitable for further studies of clinical proteomics, especially for the elucidation of the molecular mechanisms controlling iron homeostasis in normal and disease conditions.

  6. Highly nitrogen-doped carbon capsules: scalable preparation and high-performance applications in fuel cells and lithium ion batteries.

    Science.gov (United States)

    Hu, Chuangang; Xiao, Ying; Zhao, Yang; Chen, Nan; Zhang, Zhipan; Cao, Minhua; Qu, Liangti

    2013-04-07

    Highly nitrogen-doped carbon capsules (hN-CCs) have been successfully prepared by using inexpensive melamine and glyoxal as precursors via solvothermal reaction and carbonization. With a great promise for large scale production, the hN-CCs, having large surface area and high-level nitrogen content (N/C atomic ration of ca. 13%), possess superior crossover resistance, selective activity and catalytic stability towards oxygen reduction reaction for fuel cells in alkaline medium. As a new anode material in lithium-ion battery, hN-CCs also exhibit excellent cycle performance and high rate capacity with a reversible capacity of as high as 1046 mA h g(-1) at a current density of 50 mA g(-1) after 50 cycles. These features make the hN-CCs developed in this study promising as suitable substitutes for the expensive noble metal catalysts in the next generation alkaline fuel cells, and as advanced electrode materials in lithium-ion batteries.

  7. Detailed stability investigation of amorphous solid dispersions prepared by single-needle and high speed electrospinning.

    Science.gov (United States)

    Démuth, B; Farkas, A; Pataki, H; Balogh, A; Szabó, B; Borbás, E; Sóti, P L; Vigh, T; Kiserdei, É; Farkas, B; Mensch, J; Verreck, G; Van Assche, I; Marosi, G; Nagy, Z K

    2016-02-10

    In this research the long-term stability (one year) of amorphous solid dispersions (ASDs) prepared by high speed electrospinning was investigated at 25 °C/60% relative humidity (RH) (closed conditions) and 40 °C/75% RH (open conditions). Single needle electrospinning and film casting were applied as reference technologies. Itraconazole (ITR) was used as the model API in 40% concentration and the ASDs consisted of either one of the following polymers as a comparison: polyvinylpyrrolidone-vinyl acetate 6:4 copolymer (no hydrogen bonds between API and polymer) and hydroxypropyl methylcellulose (possible hydrogen bonds between oxo or tertiary nitrogen function of API and hydroxyl moiety of polymer). DSC, XRPD and dissolution characteristics of samples at 0, 3 and 12 months were investigated. In addition, Raman maps of certain electrospun ASDs were assessed to investigate crystallinity. A new chemometric method, based on Multivariate Curve Resolution-Alternating Least Squares algorithm, was developed to calculate the spectrum of amorphous ITR in the matrices and to determine the crystalline/amorphous ratio of aged samples. As it was expected ITR in single needle electrospun SDs was totally amorphous at the beginning, in addition hydroxypropyl methylcellulose could keep ITR in this form at 40 °C/75% RH up to one year due to the hydrogen bonds and high glass transition temperature of the SD. In polyvinylpyrrolidone-vinyl acetate matrix ITR remained amorphous at 25 °C/60% RH throughout one year. Materials prepared by scaled-up, high throughput version of electrospinning, which is compatible with pharmaceutical industry, also gained the same quality. Therefore these ASDs are industrially applicable and with an appropriate downstream process it would be possible to bring them to the market.

  8. Preparation of highly porous gastroretentive metformin tablets using a sublimation method.

    Science.gov (United States)

    Oh, Tack-Oon; Kim, Ju-Young; Ha, Jung-Myung; Chi, Sang-Cheol; Rhee, Yun-Seok; Park, Chun-Woong; Park, Eun-Seok

    2013-04-01

    The present investigation is aimed to formulate floating gastroretentive tablets containing metformin using a sublimation material. In this study, the release of the drug from a matrix tablet was highly dependent on the polymer concentrations. In all formulations, initial rapid drug release was observed, possibly due to the properties of the drug and polymer. The effect of the amount of PEO on swelling and eroding of the tablets was determined. The water-uptake and erosion behavior of the gastroretentive (GR) tablets were highly dependent on the amount of PEO. The water-uptake increased with increasing PEO concentration in the tablet matrix. The weight loss from tablets decreased with increasing amounts of PEO. Camphor was used as the sublimation material to prepare GR tablets that are low-density and easily floatable. Camphor was changed to pores in the tablet during the sublimation process. SEM revealed that the GR tablets have a highly porous morphology. Floating properties of tablets and tablet density were affected by the sublimation of camphor. Prepared floating gastroretentive tablets floated for over 24 h and had no floating lag time. However, as the amount of camphor in the tablet matrix increased, the crushing strength of the tablet decreased after sublimation. Release profiles of the drug from the GR tablets were not affected by tablet density or porosity. In pharmacokinetic studies, the mean plasma concentration of the GR tablets after oral administration was greater than the concentration of glucophase XR. Also, the mean AUC(0-∞) values for the GR tablets were significantly greater than the plasma concentrations of glucophase XR.

  9. New highly fluorinated styrene-based materials with low surface energy prepared by ATRP

    DEFF Research Database (Denmark)

    Borkar, Sachin; Jankova Atanasova, Katja; Siesler, Heinz W

    2004-01-01

    2,3,5,6-Tetrafluoro-4-(2,2,3,3,3-pentafluoropropoxy)styrene (TF(F-5)S) and 2,3,5,6-tetrafluoro-4-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctaoxy)styrene (TF(F,5)S) are prepared by nucleophilic substitution of 2,3,4,5,6-pentafluorostyrene. The neat monomers are subjected to atom transfer...... radical polymerization (ATRP) at 110 degreesC to high conversions in relatively short times, 10-120 min; TF(F-5)S is additionally polymerized at 70 and 90 degreesC. Block copolymers with styrene are prepared by the macroinitiator approach. All polymers, in the number-average molecular weight range from...... than 10 mol %. The fluorinated side chains of P(TF(F-5)S) and P(TF(F-15)S) enrich the surface of thin films, which results in an advancing water contact angle of 117degrees and 122degrees, respectively. Both XPS analyses and contact angle measurements strongly imply that the fluorinated parts...

  10. A facile method for preparing highly conductive and reflective surface-silvered polyimide films

    Science.gov (United States)

    Liao, Yuan; Cao, Bing; Wang, Wen-Cai; Zhang, Liqun; Wu, Dezhen; Jin, Riguang

    2009-07-01

    A novel method was developed for the preparation of reflective and electrically conductive surface-silvered polyimide (PI) films. The polyimide films were functionalized with poly(dopamine), simply by dipping the PI films into aqueous dopamine solution and mildly stirring at room temperature. Electroless plating of silver was readily carried out on the poly(dopamine) deposited PI (PI-DOPA) surface. The surface compositions of the modified PI films were studied by X-ray photoelectron spectroscopy (XPS). XPS results show that the PI-DOPA surfaces were successfully deposited with ploy(dopamine) and were ready for electroless deposition of silver. The poly(dopamine) layer was used not only as the chemi-sorption sites for silver particles during the electroless plating of silver, but also as an adhesion promotion layer for the electrolessly deposited silver. The as-prepared silvered PI films show high conductivity and reflectivity, with a surface resistance of 1.5 Ω and a reflectivity of 95%, respectively.

  11. A facile method for preparing highly conductive and reflective surface-silvered polyimide films

    Energy Technology Data Exchange (ETDEWEB)

    Liao Yuan; Cao Bing [State Key Laboratory of Chemical Resource Engineering, and the Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Beijing 100029 (China); Wang Wencai, E-mail: wangw@mail.buct.edu.cn [State Key Laboratory of Chemical Resource Engineering, and Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Beijing 100029 (China); Zhang Liqun; Wu Dezhen; Jin Riguang [State Key Laboratory of Chemical Resource Engineering, and Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Beijing 100029 (China)

    2009-07-15

    A novel method was developed for the preparation of reflective and electrically conductive surface-silvered polyimide (PI) films. The polyimide films were functionalized with poly(dopamine), simply by dipping the PI films into aqueous dopamine solution and mildly stirring at room temperature. Electroless plating of silver was readily carried out on the poly(dopamine) deposited PI (PI-DOPA) surface. The surface compositions of the modified PI films were studied by X-ray photoelectron spectroscopy (XPS). XPS results show that the PI-DOPA surfaces were successfully deposited with ploy(dopamine) and were ready for electroless deposition of silver. The poly(dopamine) layer was used not only as the chemi-sorption sites for silver particles during the electroless plating of silver, but also as an adhesion promotion layer for the electrolessly deposited silver. The as-prepared silvered PI films show high conductivity and reflectivity, with a surface resistance of 1.5 {Omega} and a reflectivity of 95%, respectively.

  12. Thermoelectric Properties of Fe1+y Te Prepared by a High Pressure Sintering Method

    Science.gov (United States)

    Di, Jiaxin; Li, Hong-Tao; Xu, Gui-Ying

    2016-11-01

    Enhancing thermoelectric properties by utilizing topological properties of topological insulators has attracted increasing attention. Here, powder metallurgy technology combined with high pressure sintering (HPS) was used to prepare Fe1+y Te (y = 0.1, 0.15, 0.1978, 0.22) alloys at 1173 K. The prepared products were identified by x-ray diffraction, and their microstructures were examined by field-emission scanning electron microscopy (FE-SEM). Electric conductivities (σ) and Seebeck coefficient (S) were measured in the temperature range of 303-623 K. The influence of variation in Fe content on thermoelectric properties was studied. The experimental results show that all HPS samples are nanometer composites consisting of Fe3Te2 and FeTe2. Fe1+y Te have electrical charges on the boundaries of topological insulators, which have the potential to be studied in the future. The Fe1+y Te with y = 0.1 shows the best thermoelectric properties at room temperature.

  13. Vinyl Ester Oligomer Crosslinked Porous Polymers Prepared via Surfactant-Free High Internal Phase Emulsions

    Directory of Open Access Journals (Sweden)

    Yun Zhu

    2012-01-01

    Full Text Available Using vinyl ester resin (VER containing styrene (or methyl methacrylate and vinyl ester oligomer (VEO as external phase, Pickering high internal phase emulsions (Pickering HIPEs having internal phase volume fraction of up to 95 vol% were prepared with copolymer particles as sole stabilizer. Polymerizing the external phase of these Pickering HIPEs led to porous polymers (poly-Pickering-HIPEs. Compared to the polystyrene- (PS- based poly-Pickering-HIPEs which were prepared with mixture of styrene and divinylbenzene (DVB as crosslinker, the poly-Pickering-HIPEs herein showed much higher elastic modulus and toughness. The elastic modulus of these poly-Pickering-HIPEs increased with increasing the VEO concentration in the external phase, while it decreased with increasing internal phase volume fraction. Increasing VEO concentration in the external phase also resulted in a decrease in the average void diameter as well as a narrow void diameter distribution of the resulting poly-Pickering-HIPEs. In addition, there were many small pores in the voids surface caused by the volume contraction of VER during the polymerization, which suggests a new method to fabricate porous polymers having a well-defined hierarchical pore structure.

  14. Wheat bran stabilization and its use in the preparation of high-fiber pasta.

    Science.gov (United States)

    Sudha, M L; Ramasarma, P R; Venkateswara Rao, G

    2011-02-01

    Wheat bran was explored as a source of fiber in the preparation of high-fiber pasta. Ground raw wheat bran having an ash content 5.99%, crude protein 15.1% and fat content 5.83% was subjected to moist heat treatment (steam heat-treated bran) and dry heat treatment (dry heat-treated bran), wherein the lipase activity was reduced by 50%. Treated bran samples were stable for 3 months without developing any rancid flavor and bitterness. Pasta samples were prepared by substituting semolina with 40% and 50% of bran samples. There was no further significant inactivation of lipase activity upon extrusion followed by drying of pasta, irrespective of the type and the amount of bran sample used. The cooked weights of the pasta were in the range 257-268 g/100 g, whereas the cooking loss decreased from 12.8% to 9.3% for treated bran-incorporated pasta. Sensory scores for pasta containing treated bran samples were higher. The total dietary fiber increased by 5.2 times upon replacement of semolina by 40% of treated wheat bran. Sodium dodecyl sulfate polyacrylamide gel electrophoresis studies showed faint bands in treated bran samples as well as treated bran-incorporated pasta samples.

  15. Biosyngas Fischer. Tropsch conversion by high Fe loaded supported catalysts prepared with ultrasound and microwave

    Energy Technology Data Exchange (ETDEWEB)

    Pirola, C.; Di Fronzo, A.; Boffito, D.C.; Bianchi, C. [Milano Univ. (Italy). Dipt. di Chimica; Di Michele, A. [Perugia Univ. (Italy). Dipt. di Fisica

    2012-07-01

    Catalysts with iron high loading of 30 wt%, promoted with K (2.0 wt%) and Cu (3.75 wt%), have been synthesized according to three different methods: (1) the traditional impregnation method (TR); (2) Ultrasound (US) assisted TR method; (3) Microwave (MW) assisted TR method. All the samples have been fully characterized by BET, ICP/OES, XRPD, TG-DTA, FT-IR, TPR, SEM and TEM and tested in a laboratory pilot plant for Fischer-Tropsch synthesis working at 220 C and 20 bar. The results of the catalysts characterization indicated that the morphology of the samples strongly depends on the method of preparation. The best FTS results in term of C{sub 2+} yield (41%) has been obtained using MW with a good value of the selectivity towards heavy hydrocarbons, while in term of CO conversion (58%), using US. The samples prepared with non-traditional methods show FTS better results, probably due to a more wide and uniform distribution of Fe in the medium during the synthesis phase. (orig.)

  16. High performance liquid chromatographic determination of some guaiphenesin-containing cough-cold preparations

    Directory of Open Access Journals (Sweden)

    Mohamed A. Korany

    2011-04-01

    Full Text Available This paper presents different HPLC methods for the simultaneous determination of some guaiphenesin-containing cough-cold preparations. Three pharmaceutically available combinations were analyzed: salbutamol sulfate (SAL and guaiphenesin (GUA, combination I; ascorbic acid (ASC, paracetamol (PAR and guaiphenesin (GUA, combination II; and theophylline anhydrous (THE, guaiphenesin (GUA and ambroxol hydrochloride (AMB, combination III. A 250 × 4.6 mm C-18 column was used for all combinations. The mobile phase for the three combinations consisted of a mixture of methanol and 0.01 M aqueous phosphate buffer solution. The pH of the mobile phase was adjusted to 3.2, 6.2 and 3.8 for combinations I, II and III, respectively. The proposed HPLC methods were successfully applied to the determination of the investigated drugs, both in synthetic mixtures and in pharmaceutical preparations, without any matrix interference and with high precision and accuracy. Different aspects of analytical validation are presented in the text.

  17. Composite nanofibers for highly efficient photocatalytic degradation of organic dyes from contaminated water.

    Science.gov (United States)

    Mohamed, Alaa; El-Sayed, Ramy; Osman, T A; Toprak, M S; Muhammed, M; Uheida, A

    2016-02-01

    In this study highly efficient photocatalyst based on composite nanofibers containing polyacrylonitrile (PAN), carbon nanotubes (CNT), and surface functionalized TiO2 nanoparticles was developed. The composite nanofibers were fabricated using electrospinning technique followed by chemical crosslinking. The surface modification and morphology changes of the fabricated composite nanofibers were examined through SEM, TEM, and FTIR analysis. The photocatalytic performance of the composite nanofibers for the degradation of model molecules, methylene blue and indigo carmine, under UV irradiation in aqueous solutions was investigated. The results demonstrated that high photodegradation efficiency was obtained in a short time and at low power intensity compared to other reported studies. The effective factors on the degradation of the dyes, such as the amount of catalyst, solution pH and irradiation time were investigated. The experimental kinetic data were fitted using pseudo-first order model. The effect of the composite nanofibers as individual components on the degradation efficiency of MB and IC was evaluated in order to understand the overall photodegradation mechanism. The results obtained showed that all the components possess significant effect on the photodegradation activity of the composite nanofibers. The stability studies demonstrated that the photodegradation efficiency can remain constant at the level of 99% after five consecutive cycles.

  18. Arsenic Removal from Water by Adsorption on Iron-Contaminated Cryptocrystalline Graphite

    Science.gov (United States)

    Yang, Qiang; Yang, Lang; Song, Shaoxian; Xia, Ling

    This work aimed to study the feasibility of using iron-contaminated graphite as an adsorbent for As(V) removal from water. The adsorbent was prepared by grinding graphite concentrate with steel ball. The study was performed through the measurements of adsorption capacity, BET surface area and XPS analysis. The experimental results showed that the iron-contaminated graphite exhibited significantly high adsorption capacity of As(V). The higher the iron contaminated on the graphite surface, the higher the adsorption capacity of As(V) on the material obtained. It was suggested that the ion-contaminated graphite was a good adsorbent for As(V) removal.

  19. Enhancement of the microbial community biomass and diversity during air sparging bioremediation of a soil highly contaminated with kerosene and BTEX.

    Science.gov (United States)

    Kabelitz, Nadja; Machackova, Jirina; Imfeld, Gwenaël; Brennerova, Maria; Pieper, Dietmar H; Heipieper, Hermann J; Junca, Howard

    2009-03-01

    In order to obtain insights in complexity shifts taking place in natural microbial communities under strong selective pressure, soils from a former air force base in the Czech Republic, highly contaminated with jet fuel and at different stages of a bioremediation air sparging treatment, were analyzed. By tracking phospholipid fatty acids and 16S rRNA genes, a detailed monitoring of the changes in quantities and composition of the microbial communities developed at different stages of the bioventing treatment progress was performed. Depending on the length of the air sparging treatment that led to a significant reduction in the contamination level, we observed a clear shift in the soil microbial community being dominated by Pseudomonads under the harsh conditions of high aromatic contamination to a status of low aromatic concentrations, increased biomass content, and a complex composition with diverse bacterial taxonomical branches.

  20. Enhancement of the microbial community biomass and diversity during air sparging bioremediation of a soil highly contaminated with kerosene and BTEX

    Energy Technology Data Exchange (ETDEWEB)

    Kabelitz, Nadja; Heipieper, Hermann J. [Helmholtz Centre for Environmental Research (UFZ), Leipzig (Germany). Dept. of Bioremediation; Machackova, Jirina [Earth Tech CZ s.r.o., Prague (Czech Republic); Imfeld, Gwenael [Helmholtz Centre for Environmental Research (UFZ), Leipzig (Germany). Dept. of Isotope Biogeochemistry; Brennerova, Maria [Czech Academy of Sciences, Prague (CZ). Inst. of Microbiology (IMIC); Pieper, Dietmar H.; Junca, Howard [Helmholtz Centre for Infection Research (HZI), Braunschweig (Germany). Biodegradation Research Group

    2009-03-15

    In order to obtain insights in complexity shifts taking place in natural microbial communities under strong selective pressure, soils from a former air force base in the Czech Republic, highly contaminated with jet fuel and at different stages of a bioremediation air sparging treatment, were analyzed. By tracking phospholipid fatty acids and 16S rRNA genes, a detailed monitoring of the changes in quantities and composition of the microbial communities developed at different stages of the bioventing treatment progress was performed. Depending on the length of the air sparging treatment that led to a significant reduction in the contamination level, we observed a clear shift in the soil microbial community being dominated by Pseudomonads under the harsh conditions of high aromatic contamination to a status of low aromatic concentrations, increased biomass content, and a complex composition with diverse bacterial taxonomical branches. (orig.)

  1. Influence of fly ash aided phytostabilisation of Pb, Cd and Zn highly contaminated soils on Lolium perenne and Trifolium repens metal transfer and physiological stress

    Energy Technology Data Exchange (ETDEWEB)

    Lopareva-Pohu, A.; Verdin, A.; Garcon, G.; Sahraoui, A.L.H.; Pourrut, B.; Debiane, D.; Waterlot, C.; Laruelle, F.; Bidar, G.; Douay, F.; Shirali, P. [University of Lille Nord France, Lille (France)

    2011-06-15

    Due to anthropogenic activities, large extends of soils are highly contaminated by Metal Trace Element (MTE). Aided phytostabilisation aims to establish a vegetation cover in order to promote in situ immobilisation of trace elements by combining the use of metal-tolerant plants and inexpensive mineral or organic soil amendments. Eight years after Coal Fly Ash (CFA) soil amendment, MTE bioavailability and uptake by two plants, Lolium perenne and Trifolium repens, were evaluated, as some biological markers reflecting physiological stress. Results showed that the two plant species under study were suitable to reduce the mobility and the availability of these elements. Moreover, the plant growth was better on CFA amended MTE-contaminated soils, and the plant sensitivity to MTE-induced physiological stress, as studied through photosynthetic pigment contents and oxidative damage was lower or similar. In conclusion, these results supported the usefulness of aided phytostabilisation of MTE-highly contaminated soils.

  2. Preparation of solid silver nanoparticles for inkjet printed flexible electronics with high conductivity

    Science.gov (United States)

    Shen, Wenfeng; Zhang, Xianpeng; Huang, Qijin; Xu, Qingsong; Song, Weijie

    2014-01-01

    Silver nanoparticles (NPs) which could be kept in solid form and were easily stored without degeneration or oxidation at room temperature for a long period of time were synthesized by a simple and environmentally friendly wet chemistry method in an aqueous phase. Highly stable dispersions of aqueous silver NP inks, sintered at room temperature, for printing highly conductive tracks (~8.0 μΩ cm) were prepared simply by dispersing the synthesized silver NP powder in water. These inks are stable, fairly homogeneous and suitable for a wide range of patterning techniques. The inks were successfully printed on paper and polyethylene terephthalate (PET) substrates using a common color printer. Upon annealing at 180 °C, the resistivity of the printed silver patterns decreased to 3.7 μΩ cm, which is close to twice that of bulk silver. Various factors affecting the resistivity of the printed silver patterns, such as annealing temperature and the number of printing cycles, were investigated. The resulting high conductivity of the printed silver patterns reached over 20% of the bulk silver value under ambient conditions, which enabled the fabrication of flexible electronic devices, as demonstrated by the inkjet printing of conductive circuits of LED devices.Silver nanoparticles (NPs) which could be kept in solid form and were easily stored without degeneration or oxidation at room temperature for a long period of time were synthesized by a simple and environmentally friendly wet chemistry method in an aqueous phase. Highly stable dispersions of aqueous silver NP inks, sintered at room temperature, for printing highly conductive tracks (~8.0 μΩ cm) were prepared simply by dispersing the synthesized silver NP powder in water. These inks are stable, fairly homogeneous and suitable for a wide range of patterning techniques. The inks were successfully printed on paper and polyethylene terephthalate (PET) substrates using a common color printer. Upon annealing at 180 °C, the

  3. Preparation of High Impermeable and Crack-resistance Chemical Admixture and Its Mechanism

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A kind of high impermeable and crack-resistance chemical admixture (HICRCA) was prepared, which is a compound chemical admixture composed of an expansion ingredient,density ingredient, and organic hydrophobic poreblocking ingredient. The results of the experiments indicate that the addition of HICRCA improves mortar and concrete in the following performances:(1) perfect workability: slump is more than 22cm, the slump after 3h is about 16cm; (2)high impermeability:for the mortar,the pervious height under a water pressure of 1.5MPa is 1.5cm,for the concrete, the pervious height under a water pressure of 5.0MPa is 2.2cm;(3)high crack-resistance:there is a micro-expansion at the age of 90d;(4)high compressivestrength:compared with the controlled concrete,the compressive strengths at the age of 3d and 28d are improved by 66.4% and 62.0%, respectively.At the same time,the effects of different curing condition on mortar and concrete expansive and shrinkage performance were studied.In addition,the impermeable and crack-resistance mechanism was investigated in the present paper.

  4. Preparation and Characterization of Porous Yttrium Oxide Powders with High Specific Surface Area

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The porous cubic yttrium oxides with high specific surface area were prepared by the explosive decomposition of yttrium nitrate and its complex formed with methyl salicylate. The specific surface area and properties of powders synthesized at various temperatures were characterized using BET, X-ray diffraction (XRD), infrared spectra (IR), and scanning electron microscopy (SEM). The results indicate that the highest specific surface area is found to be 65.37 m2*g-1 at the calcination temperature of 600 ℃, and then decreases to 20.33 m2*g-1 with the calcination temperature rising from 600 to 900 ℃. The powders show strong surface activity for adsorping water and carbon dioxide in air, which also decreases with the rising calcination temperature. The drop both on the surface area and surface activity of samples at higher temperatures may be due to pore-narrowing(sintering) effects.

  5. The preparation of highly active antimicrobial silver nanoparticles by an organometallic approach

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Eduardo J; Garcia-Barrasa, Jorge; Lopez-de-Luzuriaga, Jose M; Monge, Miguel [Departamento de Quimica Grupo de SIntesis Quimica de La Rioja, UA-CSIC, Universidad de La Rioja, Complejo CientIfico-Tecnologico, E-26004 Logrono (Spain); Laguna, Antonio [Departamento de Quimica Inorganica, Instituto de Ciencia de Materiales de Aragon, Universidad de Zaragoza-CSIC, E-50009 Zaragoza (Spain); Torres, Carmen [Departamento de Agricultura y Alimentacion, Universidad de La Rioja, Complejo Cientifico-Tecnologico, E-26004 Logrono (Spain)], E-mail: eduardo.fernandez@unirioja.es

    2008-05-07

    Silver nanoparticles of small size with a high surface to volume ratio have been prepared using an organometallic approach. For this, the complex NBu{sub 4}[Ag(C{sub 6}F{sub 5}){sub 2}] has been treated with AgClO{sub 4} in a 1:1 molar ratio, giving rise to the nanoparticle precursor [Ag(C{sub 6}F{sub 5})] in solution. Addition of one equivalent of hexadecylamine (HDA) and 5 h of reflux in toluene leads to a deep yellow solution containing monodisperse silver nanoparticles (Ag NPs) of ca. 10 nm. This approach leads to nanoparticles with almost uncontaminated surfaces which make them very reactive. Antimicrobial studies show that these nanoparticles are very active as antimicrobial agents. Very low concentrations between 12 and 25 {mu}g ml{sup -1} of Ag NPs are enough to produce bacteriostatic and bactericidal effectiveness.

  6. Low-cost preparation of mesoporous silica with high pore volume

    Institute of Scientific and Technical Information of China (English)

    Shuling Shen; Wei Wu; Kai Guo; Jianfeng Chen

    2007-01-01

    Mesoporous silica materials with high pore volume were successfully prepared by the chemical precipitation method, with water glass and a biodegradable nonionic surfactant polyethylene glycol (PEG). The obtained materials were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermo gravimetric analyzer and differential scanning calorimetry (TG-DSC), nitrogen adsorption-desorption measurements, and X-ray diffraction (XRD). The results showed that the changes of the pore parameters depended on both the surfactant content and heat treatment temperature. When the content of PEG was 10wt% and the obtained PEG/SiO2 composite was heated at 600℃, the mesoporous silica with a pore volume of 2.2 cm3/g, a BET specific surface area of 361.55 m2/g, and a diameter of 2-4 μm could be obtained. The obtained mesoporous silica materials have potential applications in the fields of paint and plastic, as thickening, reinforcing, and flatting agents.

  7. Preparation of high grade YBCO powders and pellets through the glycerol route

    Science.gov (United States)

    Kamat, R. V.; Vittal Rao, T. V.; Pillai, K. T.; Vaidya, V. N.; Sood, D. D.

    1991-10-01

    Superconducting powders and pellets of Y-Ba-Cu-O were prepared by a new solution route. Nitrates of Y, Ba and Cu were heated with a controlled amount of glycerol to get a dry powder which on suitable heat treatment gave high grade YBCO powder/pellets. Characterisation was done by X-ray diffractometry, thermogravimetry, differential thermal analysis and also by measuring the surface area, carbon-content, bulk-density, transition temperature and the critical current. The pellets could be densified to 94% theoretical density (TD) and had a superconducting transition width of 1 K. The critical current densities were in the range of 200-500 A/cm 2.

  8. Preparation of highly dispersed antimony-doped tin oxide nanopowders by azeotropic drying with isoamyl acetate

    Institute of Scientific and Technical Information of China (English)

    YANG Fen; ZHANG Xue-jun; WU Xu; TIAN Fang; GAN Fu-xing

    2007-01-01

    Antimony-doped tin hydroxide colloid precipitates were prepared by hydrolysis of SnCl4-5H2O and SbCl3 ethanol solutions. Isoamyl acetate was selected as azeotropic drying solvent and was compared with the most commonly used n-butanol solvent on treating precipitate for low hard agglomeration precursor powders. The FT-IR, BET, XRD, and TEM results of the precursor powders and calcinated antimony-doped tin oxide powders were recorded. The results demonstrate that isoamyl acetate is an excellent azeotropic drying solvent that can effectively prevent the agglomeration of particles and greatly improve the fluffiness of the obtained dried powders. After these precursor powders are calcined, antimony-doped tin oxide nanopowders with tetragonal rutile structure and high dispersivity can be obtained.

  9. Design and preparation of Zn-based materials possessing both high damping and good mechanical properties

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new idea of design and manufacture of metal-based materials possessing both high damping and good mechanical properties was proposed. The key of the idea is the combination of fining restriction-damping structures, using all mechanisms and taking advantages of different materials. Based upon this idea a foam ZA27 was prepared by the technology of prefabricated salt-mass centrifugal seeping foundry, its tensile strength and compressive strength are 83~119 MPa and 100~189 MPa, respectively. The damping properties of the foam ZA27 increase remarkably after the carpenter pastern or rosin (the damping-increased materials) was immerged into it, which approaches to the level of viscous-elastic polymer materials (Q-1≥20×10-3).

  10. Photoluminescence studies on rare earth titanates prepared by self-propagating high temperature synthesis method.

    Science.gov (United States)

    Joseph, Lyjo K; Dayas, K R; Damodar, Soniya; Krishnan, Bindu; Krishnankutty, K; Nampoori, V P N; Radhakrishnan, P

    2008-12-15

    The laser-induced luminescence studies of the rare earth titanates (R2Ti2O7) (R=La, Nd and Gd) using 355 nm radiation from an Nd:YAG laser are presented. These samples with submicron or nanometer size are prepared by the self-propagating high temperature synthesis (SHS) method and there is no known fluorescence shown by these rare earths in the visible region. Hence, the luminescence transitions shown by the La2Ti2O7 near 610 nm and Gd2Ti2O7 near 767 nm are quite interesting. Though La3+ ions with no 4f electrons have no electronic energy levels that can induce excitation and luminescence processes in the visible region, the presence of the Ti3+ ions leads to luminescence in this region.

  11. Two-step protocol for preparing adherent cells for high-throughput flow cytometry.

    Science.gov (United States)

    Kaur, Mandeep; Esau, Luke

    2015-09-01

    We have developed a simple, cost-effective, and labor-efficient two-step protocol for preparing adherent cells for high-throughput flow cytometry. Adherent cells were grown on microplates, detached with 2.9 mM EDTA (pH 6.14) added directly to wells containing cell culture medium, stained, and then analyzed on a flow cytometer. This protocol bypasses washing, centrifugation, and transfer between plates, reducing the cell loss that occurs in standard multistep protocols. The method has been validated using six adherent cell lines, four commercially available dyes, and two antibodies; the results have been confirmed using two different flow cytometry (FC) instruments. Our approach has been used for estimating apoptosis, mitochondrial membrane potential, reactive oxygen species, and autophagy in response to exposure to pure compounds as well as plant and bacterial extracts.

  12. Preparation and Properties of High Hardness and Oxidation Resisting Coating Using Electric Arc Spray

    Institute of Scientific and Technical Information of China (English)

    LIZhuo-xin; CUILi; WANGJiang-ping; TANGChun-tian

    2004-01-01

    A coating with high hardness, wear and oxidation resistance was prepared by electric arc spray. The hardness, bonding strength, abrasive wear and values of porosity and oxidation resistance of the coating were investigated. The microstructures and function of Cr3C2 of the coating were analyzed. The results showed surface Rockness Hardness HR30 reached 72.5 and average bond strength reached 49.1Mpa. Also porosity value was less than 2%. In addition, it was found from the comparison between the coating and 45CT coating that, oxidation resistance of the coating was less than that of 45CT, but the abrasive wear of the coating was obvious better than that of 45CT.

  13. Preparation of silicon carbide nitride films on Si substrate by pulsed high-energy density plasma

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Thin films of silicon carbide nitride (SiCN) were prepared on (111) oriented silicon substrates by pulsed high-energy density plasma (PHEDP). The evolution of the chemical bonding states between silicon, nitrogen and carbon was investigated as a function of discharge voltage using X-ray photoelectron spectroscopy. With an increase in discharge voltage both the C1s and N 1s spectra shift to lower binding energy due to the formation of C-Si and N-Si bonds. The Si-C-N bonds were observed in the deconvolved C1s and N 1s spectra. The X-ray diffractometer (XRD) results show that there were no crystals in the films. The thickness of the films was approximately 1-2 μm with scanning electron microscopy (SEM).

  14. Preparation and Properties of High Hardness and Oxidation Resisting Coating Using Electric Arc Spray

    Institute of Scientific and Technical Information of China (English)

    LI Zhuo-xin; CUI Li; WANG Jiang-ping; TANG Chun-tian

    2004-01-01

    A coating with high hardness, wear and oxidation resistance was prepared by electric arc spray. The hardness,bonding strength, abrasive wear and values of porosity and oxidation resistance of the coating were investigated. The microstructures and function of Cr3C2 of the coating were analyzed. The results showed surface Rockness Hardness HR30 reached 72.5 and average bond strength reached 49.1Mpa. Also porosity value was less than 2%. In addition, it was found from the comparison between the coating and 45CT coating that, oxidation resistance of the coating was less than that of 45CT, but the abrasive wear of the coating was obvious better than that of 45CT.

  15. Turbulent Flame Speeds and NOx Kinetics of HHC Fuels with Contaminants and High Dilution Levels

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Eric; Krejci, Michael; Mathieu, Olivier; Vissotski, Andrew; Ravi, Sankar; Sikes, Travis; Levacque, Anthony; Aul, Christopher; Peterson, Eric

    2011-09-30

    This progress report documents the first year of the project, from October 1, 2010 through September 30, 2011. Laminar flame speeds and ignition delay times have been measured for hydrogen and various compositions of H2/CO (syngas) at elevated pressures and elevated temperatures. Two constant-volume cylindrical vessels were used to visualize the spherical growth of the flame through the use of a schlieren optical setup to measure the laminar flame speed of the mixture. Hydrogen experiments were performed at initial pressures up to 10 atm and initial temperatures up to 443 K. A syngas composition of 50/50 was chosen to demonstrate the effect of carbon monoxide on H2-O2 chemical kinetics at standard temperature and pressures up to 10 atm. All atmospheric mixtures were diluted with standard air, while all elevated-pressure experiments were diluted with a He:O2 of 7:1 to minimize hydrodynamic instabilities. The laminar flame speed measurements of hydrogen and syngas are compared to available literature data over a wide range of equivalence ratios where good agreement can be seen with several data sets. Additionally, an improved chemical kinetics model is shown for all conditions within the current study. The model and the data presented herein agree well, which demonstrates the continual, improved accuracy of the chemical kinetics model. A high-pressure shock tube was used to measure ignition delay times for several baseline compositions of syngas at three pressures across a wide range of temperatures. The compositions of syngas (H2/CO) presented in this study include 80/20, 50/50, 40/60, 20/80, and 10/90, all of which are compared to previously published ignition delay times from a hydrogen-oxygen mixture to demonstrate the effect of carbon monoxide addition. Generally, an increase in carbon monoxide increases the ignition delay time, but there does seem to be a pressure dependency. At low temperatures and

  16. Distribution of radioactive cesium and stable cesium in cattle kept on a highly contaminated area of Fukushima nuclear accident.

    Science.gov (United States)

    Sato, Itaru; Okada, Keiji; Sasaki, Jun; Chida, Hiroyuki; Satoh, Hiroshi; Miura, Kiyoshi; Kikuchi, Kaoru; Otani, Kumiko; Sato, Shusuke

    2015-07-01

    Radioactivity inspection of slaughtered cattle is generally conducted using a portion of the neck muscle; however, there is limited information about the distribution of radioactive cesium in cattle. In this study, therefore, we measured not only radioactive cesium but also stable cesium in various tissues of 19 cattle that had been kept in the area highly contaminated by the Fukushima nuclear accident. Skeletal muscles showed approximately 1.5-3.0 times higher concentration of radioactive cesium than internal organs. Radioactive cesium concentration in the tenderloin and top round was about 1.2 times as high as that in the neck muscle. The kidney showed the highest concentration of radioactive cesium among internal organs, whereas the liver was lowest. Radioactive cesium concentration in the blood was about 8% of that in the neck muscle. Characteristics of stable cesium distribution were almost the same as those of radioactive cesium. Correlation coefficient between radioactive cesium and stable cesium in tissues of individual cattle was 0.981 ± 0.012. When a suspicious level near 100 Bq/kg is detected in the neck of slaughtered cattle, re-inspection should be conducted using a different region of muscle, for example top round, to prevent marketing of beef that violates the Food Sanitation Act. © 2014 Japanese Society of Animal Science.

  17. Arsenic contamination of the soil-wheat system irrigated with high arsenic groundwater in the Hetao Basin, Inner Mongolia, China.

    Science.gov (United States)

    Tong, Junting; Guo, Huaming; Wei, Chao

    2014-10-15

    As one of the most important crop in the world, wheat (Triticum aestivum L.) was irrigated with low As water and high As water. However, little is known about As cycling in the soil-wheat-water system. Two wheat fields (site G and site Y), irrigated with high dissolved As (178 μg L(-1)) groundwater and low dissolved As (8.2 μg L(-1)) surface water, respectively, were systematically sampled in the Hetao Basin, including irrigation water, soils and plants. The annual As (including dissolved As and suspended As) input per m(2) was estimated at 140 and 36.7 mg in site G and site Y, respectively. Topsoils of site G contained relatively higher As content (average 18.8 mg kg(-1)) than those of site Y (13.8 mg kg(-1)). Arsenic content of wheat grains in site G is systematically higher than in the site Y, which were positively correlated with non-specifically sorbed-As and amorphous Fe/Al oxide-bound As in topsoils. Arsenic-contaminated groundwater led to As accumulation in irrigated soils and the increase in As bioavailability, and subsequently resulted in the increase in As content of wheat grain. It suggested that less problematic water resources should be used for wheat irrigation in order to avoid As accumulation in the soil-plant system. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Preparation and characterization of paclitaxel nanosuspension using novel emulsification method by combining high speed homogenizer and high pressure homogenization.

    Science.gov (United States)

    Li, Yong; Zhao, Xiuhua; Zu, Yuangang; Zhang, Yin

    2015-07-25

    The aim of this study was to develop an alternative, more bio-available, better tolerated paclitaxel nanosuspension (PTXNS) for intravenous injection in comparison with commercially available Taxol(®) formulation. In this study, PTXNS was prepared by emulsification method through combination of high speed homogenizer and high pressure homogenization, followed by lyophilization process for intravenous administration. The main production parameters including volume ratio of organic phase in water and organic phase (Vo:Vw+o), concentration of PTX, content of PTX and emulsification time (Et), homogenization pressure (HP) and passes (Ps) for high pressure homogenization were optimized and their effects on mean particle size (MPS) and particle size distribution (PSD) of PTXNS were investigated. The characteristics of PTXNS, such as, surface morphology, physical status of paclitaxel (PTX) in PTXNS, redispersibility of PTXNS in purified water, in vitro dissolution study and bioavailability in vivo were all investigated. The PTXNS obtained under optimum conditions had an MPS of 186.8 nm and a zeta potential (ZP) of -6.87 mV. The PTX content in PTXNS was approximately 3.42%. Moreover, the residual amount of chloroform was lower than the International Conference on Harmonization limit (60 ppm) for solvents. The dissolution study indicated PTXNS had merits including effect to fast at the side of raw PTX and sustained-dissolution character compared with Taxol(®) formulation. Moreover, the bioavailability of PTXNS increased 14.38 and 3.51 times respectively compared with raw PTX and Taxol(®) formulation.

  19. Ge Implantation to Improve Crystallinity and Productivity for Solid Phase Epitaxy Prepared by Atomic Mass Unit Cross Contamination-Free Technique

    Science.gov (United States)

    Lee, Kong-Soo; Yoo, Dae-Han; Han, Jae-Jong; Son, Gil-Hwan; Lee, Chang-Hun; Noh, Ju-Hee; Kim, Seok-Jae; Kim, Yong-Kwon; You, Young-Sub; Hyung, Yong-Woo; Lee, Hyeon-Deok

    2006-11-01

    Germanium (Ge) ion implantation was investigated for crystallinity enhancement during solid phase epitaxial (SPE) regrowth. Electron back-scatter diffraction (EBSD) measurement showed numerical increase of 19% of (100) signal, which might be due to the effect of pre-amorphization implantation (PAI) on silicon layer. On the other hand, electrical property such as off-leakage current of n-channel metal oxide semiconductor (NMOS) transistor degraded in specific regions of wafers. It was confirmed that arsenic (As) atoms were incorporated into channel area during Ge ion implantation. Since the equipment for Ge PAI was using several source gases such as BF3 and AsH3, atomic mass unit (AMU) contamination during PAI of Ge with AMU 74 caused the incorporation of As with AMU 75 which resided in arc-chamber and other parts of the equipment. It was effective to use Ge isotope of AMU 72 to suppress AMU contamination. It was effective to use enriched Ge source gas with AMU 72 in order to improve productivity.

  20. Bioleaching of arsenic from highly contaminated mine tailings using Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Lee, Eunseong; Han, Yosep; Park, Jeonghyun; Hong, Jeongsik; Silva, Rene A; Kim, Seungkon; Kim, Hyunjung

    2015-01-01

    The behavior of arsenic (As) bioleaching from mine tailings containing high amount of As (ca. 34,000 mg/kg) was investigated using Acidithiobacillus thiooxidans to get an insight on the optimal conditions that would be applied to practical heap and/or tank bioleaching tests. Initial pH (1.8-2.2), temperature (25-40 °C), and solid concentration (0.5-4.0%) were employed as experimental parameters. Complementary characterization experiments (e.g., XRD, SEM-EDS, electrophoretic mobility, cell density, and sulfate production) were also carried out to better understand the mechanism of As bioleaching. The results showed that final As leaching efficiency was similar regardless of initial pH. However, greater initial As leaching rate was observed at initial pH 1.8 than other conditions, which could be attributed to greater initial cell attachment to mine tailings. Unlike the trend observed when varying the initial pH, the final As leaching efficiency varied with the changes in temperature and solid concentration. Specifically, As leaching efficiency tended to decrease with increasing temperature due to the decrease in the bacterial growth rate at higher temperature. Meanwhile, As leaching efficiency tended to increase with decreasing solid concentration. The results for jarosite contents in mine tailings residue after bioleaching revealed that much greater amount of the jarosite was formed during the bioleaching reaction at higher solid concentration, suggesting that the coverage of the surface of the mine tailings by jarosite and/or the co-precipitation of the leached As with jarosite could be a dominant factor reducing As leaching efficiency. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. The method of production and modification of highly disperse silica for pharmaceutical and cosmetic preparations

    Directory of Open Access Journals (Sweden)

    Nina N. Mofa

    2015-12-01

    Full Text Available The change in the dispersity, morphology and state of amorphous silicon dioxide (silica powder depending on the conditions of mechanochemical treatment (MCT in the mill of dynamic action and ultrasonic treatment (UST in different aqueous solution is considered. Production of silicon dioxide in a highly disperse state is of importance, when using it in cosmetic and pharmaceutical preparations. Nanosilicic compositions are effective for delivering medicines to the connective tissues of the skin structure. When dispersing powder as surfactant and modifying additives, we used monoatomic and triatomic alcohols as well as succinic and acetylsalicylic acids, which provide a high level of grinding, modification of the particle surface and stabilization of a highly active state of silicon dioxide. Electron-microscopic investigations on the morphology of particles showed their capsulation into dense modifying films under the conditions of MCT and UST. The use of acid modifiers in the process of MCT and UST of silicon dioxide powder resulted in formation of complex composition systems consisting of an inorganic nucleus and organic capsulating film. The state of the obtained modified powders was evaluated by the change of electrical resistance as one of the most sensitive indices of structural changes of the system being treated. The use of triatomic alcohol glycerine, when treating the powder, noticeably decreased its specific electrical resistance after UST, due to formation of hydroxylic groups on the surface of particles and accumulation of charged particles, which provide a high chemical activity of the systems. An important role of the capsulating polymer component on the surface of highly disperse particles of silicon dioxide for stabilization of a highly active state of the powder is shown.

  2. High-Resolution Flow Logging for Hydraulic Characterization of Boreholes and Aquifer Flow Zones at Contaminated Bedrock Sites

    Science.gov (United States)

    Williams, J. H.; Johnson, C. D.; Paillet, F. L.

    2004-05-01

    In the past, flow logging was largely restricted to the application of spinner flowmeters to determine flow-zone contributions in large-diameter production wells screened in highly transmissive aquifers. Development and refinement of tool-measurement technology, field methods, and analysis techniques has greatly extended and enhanced flow logging to include the hydraulic characterization of boreholes and aquifer flow zones at contaminated bedrock sites. State-of-the-art in flow logging will be reviewed, and its application to bedrock-contamination investigations will be presented. In open bedrock boreholes, vertical flows are measured with high-resolution flowmeters equipped with flexible rubber-disk diverters fitted to the nominal borehole diameters to concentrate flow through the measurement throat of the tools. Heat-pulse flowmeters measure flows in the range of 0.05 to 5 liters per minute, and electromagnetic flowmeters measure flows in the range of 0.3 to 30 liters per minute. Under ambient and low-rate stressed (either extraction or injection) conditions, stationary flowmeter measurements are collected in competent sections of the borehole between fracture zones identified on borehole-wall images. Continuous flow, fluid-resistivity, and temperature logs are collected under both sets of conditions while trolling with a combination electromagnetic flowmeter and fluid tool. Electromagnetic flowmeters are used with underfit diverters to measure flow rates greater than 30 liters per minute and suppress effects of diameter variations while trolling. A series of corrections are applied to the flow-log data to account for the zero-flow response, bypass, trolling, and borehole-diameter biases and effects. The flow logs are quantitatively analyzed by matching simulated flows computed with a numerical model to measured flows by varying the hydraulic properties (transmissivity and hydraulic head) of the flow zones. Several case studies will be presented that demonstrate

  3. Short communication: Inactivation of microbial contaminants in raw milk La Serena cheese by high-pressure treatments.

    Science.gov (United States)

    Arqués, J L; Garde, S; Gaya, P; Medina, M; Nuñez, M

    2006-03-01

    La Serena cheese, a Spanish variety made from Merino ewes' raw milk, has a high pH value, low salt content, and high moisture, conditions that are all favorable for growth and survival of contaminating microorganisms, including pathogens. To improve its microbiological quality and safety, high-pressure treatments at 300 or 400 MPa for 10 min at 10 degrees C were applied to 2 batches of La Serena cheese on d 2 or 50 of ripening. Cheese treated on d 2 at 300 MPa showed viable aerobic counts that were 0.99 log units lower than those for control cheese on d 3 and showed counts of enterococci, coagulase-positive staphylococci, gram-negative bacteria, and coliforms that were 2.05, 0.49, 3.14, and 4.13 log units lower, respectively, than control cheese. For cheese treated on d 2 at 400 MPa, the respective reductions in counts were 2.02, 2.68, 1.45, 3.96, and 5.50 log units. On d 60, viable aerobic counts in cheese treated on d 50 at 300 MPa were 0.50 log units lower than those in control cheese, and counts of enterococci, gram-negative bacteria, and coliforms were 1.37, 2.30, and 4.85 log units lower, respectively. For cheese treated on d 50 at 400 MPa, the respective reductions in counts were 1.29, 1.98, 4.47, and > 5 log units. High-pressure treatments at 300 or 400 MPa on d 2 or 50 reduced significantly the counts of undesirable microorganisms, improving the microbiological quality and safety of La Serena cheese immediately after treatment and at the end of the ripening period.

  4. A Study of the Preparation and Properties of Antioxidative Copper Inks with High Electrical Conductivity.

    Science.gov (United States)

    Tsai, Chia-Yang; Chang, Wei-Chen; Chen, Guan-Lin; Chung, Cheng-Huan; Liang, Jun-Xiang; Ma, Wei-Yang; Yang, Tsun-Neng

    2015-12-01

    Conductive ink using copper nanoparticles has attracted much attention in the printed electronics industry because of its low cost and high electrical conductivity. However, the problem of easy oxidation under heat and humidity conditions for copper material limits the wide applications. In this study, antioxidative copper inks were prepared by dispersing the nanoparticles in the solution, and then conductive copper films can be obtained after calcining the copper ink at 250 °C in nitrogen atmosphere for 30 min. A low sheet resistance of 47.6 mΩ/□ for the copper film was measured by using the four-point probe method. Importantly, we experimentally demonstrate that the electrical conductivity of copper films can be improved by increasing the calcination temperature. In addition, these highly conductive copper films can be placed in an atmospheric environment for more than 6 months without the oxidation phenomenon, which was verified by energy-dispersive X-ray spectroscopy (EDS). These observations strongly show that our conductive copper ink features high antioxidant properties and long-term stability and has a great potential for many printed electronics applications, such as flexible display systems, sensors, photovoltaic cells, and radio frequency identification.

  5. Preparation of high nitrogen and nickel-free austenitic stainless steel by powder injection molding

    Institute of Scientific and Technical Information of China (English)

    Dawei Cui; Junsheng Jiang; Guangming Cao; Enzhong Xiao; Xuanhui Qu

    2008-01-01

    High nitrogen and nickel-free austenitic stainless steel has received much recognition worldwide because it can solve the problem of "nickel-allergy" and has outstanding mechanical and physical properties. In this article, 0Cr17Mn11Mo3N was prepared by powder injection molding (PIM) technique accompanied with solid-nitriding. The results show that the critical solid loading can achieve up to 64vo1% by use of gas-atomized powders with the average size of 17.4 μm. The optimized sintering conditions are de- termined to be 1300℃,2 h in flowing nitrogen atmosphere, at which the relative density reaches to 99% and the N content is as high as 0.78wt%. After solution annealing at 1150℃for 90 min and water quench, the 0.2% yield strength, ultimate tensile strength (UTS), elongation, reduction in area, and hardness can reach as high as 580 MPa, 885 MPa, 26.0%, 29.1%, and Hv 222, respectively. C 2008 University of Science and Technology Beijing. All rights reserved.

  6. Preparation of Vanadium Dioxide Films for Protection from High-energy Laser Hits

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Vanadium dioxide(VO2)thin films are used for protection from high-energy laser hits due to their semiconductor-to-metal phase transition experienced during heating at temperature of approximately 68℃,which followed by a abrupt change of optical behavior, namely from transparent semiconductor state below 68℃ to highly reflective metallic state beyond 68℃.The preparation and properties of the films are described as well as the primary principle of the device for protection from high energy laser hits. An ion-beam-sputtering system is used to deposit VO2 thin films.The technique is reactive ion beam sputtering of vanadium at temperature of 200℃ on Si, Ge and Si3N4 substrates in a well controlled atmosphere of argon with a partial pressure of O2, followed by a post annealing at 400-550℃ with argon gas.The optical transmittance changes from 60% to 4% are obtained within the temperature range from 50℃ to 70℃. X-ray diffraction (XRD) shows that the films are of single-phase VO2.

  7. Ultramicro molybdenum nitride powder prepared using high-energy mechanochemical method

    Institute of Scientific and Technical Information of China (English)

    AN Geng; LIU Gaojie

    2008-01-01

    Using the specially designed mechanochemical ball-mill equipment, ultramicro molybdenum nitride powders were prepared from pure molybdenum powders in ammonia atmosphere at room temperature by high-energy ball milling. The structure and the particle size of the powders were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that the mass ratio of grinding media to powder was 8:1, after milling for 30h the Mo2N of fcc structure was obtained, and the average particle size of the powders was around 100 nm. It is found that the chemisorption of ammonia onto the fresh molybdenum surfaces created by milling was the predominant process during solid-gas reaction, and the energy input due to introduction of highly dense grain boundaries and lattice defects offered the activation energy for the transition from Mo-N chemisorption to molybdenum nitride. In addition, the change of Mo electronic undersaturation induced by the grain refining accelerated the bonding between Mo and N. The mechanism model of whole nitriding reaction was given. During the high-energy ball milling processing, the rotational speed of milling played a critical role in determining the overall reaction speed.

  8. Preparation and characterization of highly active nanosized strontium-doped lanthanum cobaltate catalysts with high surface areas

    Institute of Scientific and Technical Information of China (English)

    NIU Jianrong; LIU Wei; DAI Hongxing; HE Hong; ZI Xuehong; LI Peiheng

    2006-01-01

    La1-xSrxCoO3-δ (x=0, 0.4) nanoparticles have been prepared using the citric acid complexing-hydrothermal synthesis coupled method and citric acid complexing method. The physico-chemical properties of these materials were characterized by means of X-ray diffraction (XRD), high resolution scanning electron microscopy (HRSEM), element analysis (EDX), X-ray photoelectron spectroscopic (XPS), oxygen temperature-programmed desorption (O2-TPD), hydrogen temperature-programmed reduction (H2-TPR) as well as surface area measurements and oxidation state titration. Their catalytic performance was examined for the total oxidation of ethylacetate (EA). It is found that the La1-xSrxCoO3-δ (x=0, 0.4) catalysts were single-phase and rhombohedrally-structured perovskites and their surface areas ranged from 16 to 26 m2/g. The Sr-doped sample derived from the coupled procedure was uniformly distributed nanoparticles with a short rod-shaped morphology. The doping of Sr (i) enhanced the concentrations of Co3+ and oxygen vacancies, (ii) increased the amount of oxygen adsorbed on the surface at low temperatures, (iii) promoted the mobility of lattice oxygen, and (iv) improved the properties of redox. The La0.6Sr0.4CoO2.78 catalyst prepared by the citric acid complexing-hydrothermal synthesis coupled strategy performed the best in the oxidation of EA, furthermore no partially oxidized products were formed. Based on the above results, we conclude that in addition to the surface area, the catalytic activity of the perovskite-type oxide nanoparticles was associated with the structural defect (oxygen vacancy)concentration and redox ability.

  9. Turbulent flame speeds and NOx kinetics of HHC fuels with contaminants and high dilution levels

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Eric; Krejci, Michael; Mathieu, Olivier; Vissotski, Andrew; Ravi, Sankar; Plichta, Drew; Sikes, Travis; Levacque, Anthony; Aul, Christopher; Petersen, Eric

    2012-09-30

    This progress report documents the second year of the project, from October 1, 2011 through September 30, 2012. Characterization of the new turbulent flame speed vessel design was completed. Turbulence statistics of three impellers with different geometric features were measured using particle image velocimetry inside a Plexiglas model (~1:1 scale) of a cylindrical flame speed vessel (30.5 cm ID × 35.6 cm L). With four impellers arranged in a central-symmetric configuration, turbulence intensities between 1.2 and 1.7 m/s with negligible mean flow (0.1u´) were attained at the lowest fan speeds. Acceptable ranges for homogeneity and isotropy ratios of the velocity fields were set within a narrow bandwidth near unity (0.9-1.1). Homogeneity ratios were unaffected by changes to the impeller geometry, and the prototype with the higher number of blades caused the flow to become anisotropic. The integral length scale of the flow fields varied between 27 and 20 mm, which correlates well with those typically observed inside a gas turbine combustor. The mechanism to independently vary the intensity level and the integral length scale was established, where turbulence intensity level was dependent on the rotational speed of the fan, and the integral length scale decreased with increasing blade pitch angle. Ignition delay times of H₂/O₂ mixtures highly diluted with Ar and doped with various amounts of N₂O (100, 400, 1600, 3200 ppm) were measured in a shock tube behind reflected shock waves over a wide range of temperatures (940-1675 K). The pressure range investigated during this work (around 1.6, 13, and 30 atm) allows studying the effect of N₂O on hydrogen ignition at pressure conditions that have never been heretofore investigated. Ignition delay times were decreased when N₂O was added to the mixture only for the higher nitrous oxide concentrations, and some changes in the activation energy were also observed at 1.5 and 30 atm. When it occurred, the decrease in

  10. Multicapillary SDS-gel electrophoresis for the analysis of fluorescently labeled mAb preparations: a high throughput quality control process for the production of QuantiPlasma and PlasmaScan mAb libraries.

    Science.gov (United States)

    Székely, Andrea; Szekrényes, Akos; Kerékgyártó, Márta; Balogh, Attila; Kádas, János; Lázár, József; Guttman, András; Kurucz, István; Takács, László

    2014-08-01

    Molecular heterogeneity of mAb preparations is the result of various co- and post-translational modifications and to contaminants related to the production process. Changes in molecular composition results in alterations of functional performance, therefore quality control and validation of therapeutic or diagnostic protein products is essential. A special case is the consistent production of mAb libraries (QuantiPlasma™ and PlasmaScan™) for proteome profiling, quality control of which represents a challenge because of high number of mAbs (>1000). Here, we devise a generally applicable multicapillary SDS-gel electrophoresis process for the analysis of fluorescently labeled mAb preparations for the high throughput quality control of mAbs of the QuantiPlasma™ and PlasmaScan™ libraries. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Complexity of Groundwater Contaminants at DOE Sites

    Energy Technology Data Exchange (ETDEWEB)

    Hazen, T.C.; Faybishenko, B.; Jordan, P.

    2010-12-03

    The U.S. Department of Energy (DOE) is responsible for the remediation and long-term stewardship of one of the world's largest groundwater contamination portfolios, with a significant number of plumes containing various contaminants, and considerable total mass and activity. As of 1999, the DOE's Office of Environmental Management was responsible for remediation, waste management, or nuclear materials and facility stabilization at 144 sites in 31 states and one U.S. territory, out of which 109 sites were expected to require long-term stewardship. Currently, 19 DOE sites are on the National Priority List. The total number of contaminated plumes on DOE lands is estimated to be 10,000. However, a significant number of DOE sites have not yet been fully characterized. The most prevalent contaminated media are groundwater and soil, although contaminated sediment, sludge, and surface water also are present. Groundwater, soil, and sediment contamination are present at 72% of all DOE sites. A proper characterization of the contaminant inventory at DOE sites is critical for accomplishing one of the primary DOE missions -- planning basic research to understand the complex physical, chemical, and biological properties of contaminated sites. Note that the definitions of the terms 'site' and 'facility' may differ from one publication to another. In this report, the terms 'site,' 'facility' or 'installation' are used to identify a contiguous land area within the borders of a property, which may contain more than one plume. The term 'plume' is used here to indicate an individual area of contamination, which can be small or large. Even though several publications and databases contain information on groundwater contamination and remediation technologies, no statistical analyses of the contaminant inventory at DOE sites has been prepared since the 1992 report by Riley and Zachara. The DOE Groundwater Data Base

  12. Complexity of Groundwater Contaminants at DOE Sites

    Energy Technology Data Exchange (ETDEWEB)

    Hazen, T.C.; Faybishenko, B.; Jordan, P.

    2010-12-03

    The U.S. Department of Energy (DOE) is responsible for the remediation and long-term stewardship of one of the world's largest groundwater contamination portfolios, with a significant number of plumes containing various contaminants, and considerable total mass and activity. As of 1999, the DOE's Office of Environmental Management was responsible for remediation, waste management, or nuclear materials and facility stabilization at 144 sites in 31 states and one U.S. territory, out of which 109 sites were expected to require long-term stewardship. Currently, 19 DOE sites are on the National Priority List. The total number of contaminated plumes on DOE lands is estimated to be 10,000. However, a significant number of DOE sites have not yet been fully characterized. The most prevalent contaminated media are groundwater and soil, although contaminated sediment, sludge, and surface water also are present. Groundwater, soil, and sediment contamination are present at 72% of all DOE sites. A proper characterization of the contaminant inventory at DOE sites is critical for accomplishing one of the primary DOE missions -- planning basic research to understand the complex physical, chemical, and biological properties of contaminated sites. Note that the definitions of the terms 'site' and 'facility' may differ from one publication to another. In this report, the terms 'site,' 'facility' or 'installation' are used to identify a contiguous land area within the borders of a property, which may contain more than one plume. The term 'plume' is used here to indicate an individual area of contamination, which can be small or large. Even though several publications and databases contain information on groundwater contamination and remediation technologies, no statistical analyses of the contaminant inventory at DOE sites has been prepared since the 1992 report by Riley and Zachara. The DOE Groundwater Data Base

  13. Immunocompromentation of persons from groups with high risk of parenteral contamination with hepatitis B and C viruses: mechanisms of development and clinical pathogenetical significance

    Directory of Open Access Journals (Sweden)

    M. K. Mamedov

    2012-01-01

    Full Text Available The paper contains data demonstrated that majority of persons belonged to groups with high risk of parenteral contamination with hepatitis B and C viruses yet before contamination with these viruses have complex of immunological disorders. In the article is presented the data reflecting main causes of these disorders development at different categories of such persons and main aspects of their pathogenetical and clinical significance are discussed.

  14. Ultra high strain properties of lanthanum substituted PZT electro-ceramics prepared via mechanical activation

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ajeet, E-mail: jkajeet@yahoo.co.in [Ceramics and Composites Group, Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); School of Physics, University of Hyderabad, Hyderabad 500046 (India); Bhanu Prasad, V.V., E-mail: bhanu@dmrl.drdo.in [Ceramics and Composites Group, Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); James Raju, K.C., E-mail: kcjrsp@yahoo.com [School of Physics, University of Hyderabad, Hyderabad 500046 (India); James, A.R., E-mail: james@dmrl.drdo.in [Ceramics and Composites Group, Defence Metallurgical Research Laboratory, Hyderabad 500058 (India)

    2014-06-25

    Highlights: • PLZT comparable with PMN–PT and their hot-pressed counterparts synthesized. • HEM applied for ceramic preparation at reduced sintering temperature. • Strain value (0.27%) comparable to previous reported values for PLZT 8/60/40. • The electric field induced (strain) hysteresis loss was also found to be very less. - Abstract: Substitution of lanthanum at the A sites of perovskite lead zirconate titanate ceramics shows an improvement in the structural and electrical properties. (Pb{sub 0.92}La{sub 0.08})(Zr{sub 0.60}Ti{sub 0.40})O{sub 3} (PLZT 8/60/40) was prepared using high energy mechano-chemical milling. The effect of milling on the microstructure and electrical properties of PLZT 8/60/40 has been studied. X-ray diffraction shows the phase formation after milling itself. TEM was used to measure the particle size. The SEM image of the sintered pellet shows a dense microstructure and the average grain size was found to be <1.5 μm. Electrical properties of the ceramics were characterized. Piezoelectric charge coefficient (d{sub 33}) was found to be 561 pC/N. Resonance studies were performed on poled ceramics and the electromechanical coupling factor was calculated by the resonance method. The PLZT 8/60/40 composition showed a well saturated and uniform P–E hysteresis loop with remanent polarization (P{sub r}) of 33.29 μC/cm{sup 2} and a coercive field (E{sub c}) of 10.57 kV/cm. Electric field induced strain (S–E loop) shows a value of ∼0.27% with minimum loss.

  15. Do new cellulolytic enzyme preparations affect the industrial strategies for high solids lignocellulosic ethanol production?

    Science.gov (United States)

    Cannella, David; Jørgensen, Henning

    2014-01-01

    Production of ethanol from lignocellulosic materials has a promising market potential, but the process is still only at pilot/demonstration scale due to the technical and economical difficulties of the process. Operating the process at very high solids concentrations (above 20% dry matter-DM) has proven essential for economic feasibility at industrial scale. Historically, simultaneous saccharification and fermentation (SSF) was found to give better ethanol yields compared to separate hydrolysis and fermentation (SHF), but data in literature are typically based on operating the process at low dry matter conditions. In this work the impact of selected enzyme preparation and processing strategy (SHF, presaccharification and simultaneous saccharification and fermentation-PSSF, and SSF) on final ethanol yield and overall performance was investigated with pretreated wheat straw up to 30% DM. The experiments revealed that an SSF strategy was indeed better than SHF when applying an older generation enzyme cocktail (Celluclast-Novozym 188). In case of the newer product Cellic CTec 2, SHF resulted in 20% higher final ethanol yield compared to SSF. It was possible to close the mass balance around cellulose to around 94%, revealing that the most relevant products could be accounted for. One observation was the presence of oxidized sugar (gluconic acid) upon enzymatic hydrolysis with the latest enzyme preparation. Experiments showed gluconic acid formation by recently discovered enzymatic class of lytic polysaccharides monoxygenases (LPMO's) to be depending on the processing strategy. The lowest concentration was achieved in SSF, which could be correlated with less available oxygen due to simultaneous oxygen consumption by the yeast. Quantity of glycerol and cell mass was also depending on the selected processing strategy.

  16. An effective method for the preparation of high temperature stable anatase TiO2 photocatalysts

    Science.gov (United States)

    Fagan, Rachel; Synnott, Damian W.; McCormack, Declan E.; Pillai, Suresh C.

    2016-05-01

    An efficient, rapid and straightforward method for the preparation of nitrogen and fluorine (N, F) codoped high temperature stable anatase using a microwave pre-treatment is reported. Using a single source, ammonium fluoride (NH4F) for both nitrogen and fluorine, effective doping of the precursor titanium isopropoxide (TTIP) was possible. These samples were characterised for their structural and optical properties using X-ray diffraction (XRD), Fourier Transform IR (FTIR), Raman spectroscopy and UV-vis spectroscopy. In terms of the anatase to rutile transition enhancement using a novel microwave assisted technique, the sample prepared in a composition of 1:8 TiO2: NH4F at 1200 °C was seen to be most effective, having stable anatase present at 57.1% compared to undoped TiO2 being 100% rutile from 900 °C. This method involves the production of ammonium oxofluorotitanates (NH4TiOF3) at low temperatures. The inclusion of these intermediates greatly reduces the particle size growth and delays the anatase to rutile transition. The photocatalytic activity of these materials was studied by analysing the degradation of an organic dye, rhodamine 6G as a model system and the rate constant was calculated by pseudo-first-order kinetics. These results showed that the doped sample (0.0225 min-1) was three times more active than the undoped sample (0.0076 min-1) and over seven times faster than the commercial TiO2 photocatalyst standard Degussa P-25 calcined at 1200 °C (0.0030 min-1). The formation of intermediate compounds, oxofluorotitanates, was identified as the major reason for a delay in the anatase to rutile transition.

  17. New Method to Prepare Mitomycin C Loaded PLA-Nanoparticles with High Drug Entrapment Efficiency

    Science.gov (United States)

    Hou, Zhenqing; Wei, Heng; Wang, Qian; Sun, Qian; Zhou, Chunxiao; Zhan, Chuanming; Tang, Xiaolong; Zhang, Qiqing

    2009-07-01

    The classical utilized double emulsion solvent diffusion technique for encapsulating water soluble Mitomycin C (MMC) in PLA nanoparticles suffers from low encapsulation efficiency because of the drug rapid partitioning to the external aqueous phase. In this paper, MMC loaded PLA nanoparticles were prepared by a new single emulsion solvent evaporation method, in which soybean phosphatidylcholine (SPC) was employed to improve the liposolubility of MMC by formation of MMC-SPC complex. Four main influential factors based on the results of a single-factor test, namely, PLA molecular weight, ratio of PLA to SPC (wt/wt) and MMC to SPC (wt/wt), volume ratio of oil phase to water phase, were evaluated using an orthogonal design with respect to drug entrapment efficiency. The drug release study was performed in pH 7.2 PBS at 37 °C with drug analysis using UV/vis spectrometer at 365 nm. MMC-PLA particles prepared by classical method were used as comparison. The formulated MMC-SPC-PLA nanoparticles under optimized condition are found to be relatively uniform in size (594 nm) with up to 94.8% of drug entrapment efficiency compared to 6.44 μm of PLA-MMC microparticles with 34.5% of drug entrapment efficiency. The release of MMC shows biphasic with an initial burst effect, followed by a cumulated drug release over 30 days is 50.17% for PLA-MMC-SPC nanoparticles, and 74.1% for PLA-MMC particles. The IR analysis of MMC-SPC complex shows that their high liposolubility may be attributed to some weak physical interaction between MMC and SPC during the formation of the complex. It is concluded that the new method is advantageous in terms of smaller size, lower size distribution, higher encapsulation yield, and longer sustained drug release in comparison to classical method.

  18. Food Safety and Bioavailability Evaluations of Four Vegetables Grown in the Highly Arsenic-Contaminated Soils on the Guandu Plain of Northern Taiwan

    Directory of Open Access Journals (Sweden)

    Shaw-Wei Su

    2014-04-01

    Full Text Available Arsenic contamination in a large area of agricultural fields on the Guandu Plain of northern Taiwan was confirmed in a survey conducted in 2006, but research concerning the relationship between bioavailable As concentrations in contaminated soils and crop production in Taiwan is not available. Pot experiments were conducted to examine the growth and accumulation of As in four vegetable crops grown in As-contaminated soils and to assess As intake through consumption. The phytotoxic effects of As in soils were not shown in the pot experiments in which vegetable crops were grown in soils contaminated with different As levels in situ collected from Guandu Plain (120–460 mg/kg or artificially spiked As-contaminated soils (50–170 mg/kg. Experimental results showed that the bioavailable As extracted with 0.5M NaHCO3 from soils can be used to estimate As concentrations in vegetables. The As concentrations in the vegetables were compared with data shown in the literature and As limits calculated from drinking water standards and the provisional tolerance weekly intake (PTWI of inorganic As established by the Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO. Although the As levels in the vegetables were not high and the bioavailability of As in the soils was quite low, long-term consumption may result in higher As intake in the human body.

  19. Food safety and bioavailability evaluations of four vegetables grown in the highly arsenic-contaminated soils on the Guandu Plain of northern Taiwan.

    Science.gov (United States)

    Su, Shaw-Wei; Tsui, Chun-Chih; Lai, Hung-Yu; Chen, Zueng-Sang

    2014-04-14

    Arsenic contamination in a large area of agricultural fields on the Guandu Plain of northern Taiwan was confirmed in a survey conducted in 2006, but research concerning the relationship between bioavailable As concentrations in contaminated soils and crop production in Taiwan is not available. Pot experiments were conducted to examine the growth and accumulation of As in four vegetable crops grown in As-contaminated soils and to assess As intake through consumption. The phytotoxic effects of As in soils were not shown in the pot experiments in which vegetable crops were grown in soils contaminated with different As levels in situ collected from Guandu Plain (120-460 mg/kg) or artificially spiked As-contaminated soils (50-170 mg/kg). Experimental results showed that the bioavailable As extracted with 0.5M NaHCO3 from soils can be used to estimate As concentrations in vegetables. The As concentrations in the vegetables were compared with data shown in the literature and As limits calculated from drinking water standards and the provisional tolerance weekly intake (PTWI) of inorganic As established by the Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO). Although the As levels in the vegetables were not high and the bioavailability of As in the soils was quite low, long-term consumption may result in higher As intake in the human body.

  20. Removal of As, Cd, Cu, Ni, Pb, and Zn from a highly contaminated industrial soil using surfactant enhanced soil washing

    Science.gov (United States)

    Torres, Luis G.; Lopez, Rosario B.; Beltran, Margarita

    Surfactant enhanced soil washing (SESW) was applied to an industrial contaminated soil. A preliminary characterization of the soil regarding the alkaline-earth metals, Na, K, Ca and Mg took values of 2866, 2036, 2783 and 4149 mg/kg. The heavy metals As, Cd, Cu, Pb, Ni and Zn, had values of 4019, 14, 35582, 70, 2603, and 261 mg/kg, respectively. When using different surfactants, high removal of Cu, Ni and Zn were found, and medium removals for Pb, As and Cd. In the case of these three metals, tap water removed more than the surfactant solutions, except for the case of As. There were surfactants with average removals (this is, the removal for all the metals studied) of 67.1% (Tween 80), 64.9% (Surfacpol 14104) and 61.2% (Emulgin W600). There were exceptional removals using Texapon N-40 (83.2%, 82.8% and 86.6% for Cu, Ni and Zn), Tween 80 (85.9, 85.4 and 81.5 for Cd, Zn and Cu), Polafix CAPB (79%, 83.2% and 49.7% for Ni, Zn and As). The worst results were obtained with POLAFIX LO with a global removal of 45%, well below of the average removal with tap water (50.2%).All removal efficiencies are reported for a one step washing using 0.5% surfactant solutions, except for the case of mezquite gum, where a 0.1% solution was employed.

  1. Gettering of diffused Au and of Cu and Ni contamination in silicon by cavities induced by high energy He implantation

    Energy Technology Data Exchange (ETDEWEB)

    Bouayadi, R. el; Regula, G.; Pichaud, B.; Lancin, M. [Faculte des Sciences et Techniques de St Jerome, Marseille (France). Lab. TECSEN; Dubois, C.; Ntsoenzok, E.

    2000-11-01

    Silicon samples were gold-diffused at different temperatures (870-950 C) and implanted with He ions at 1.6 MeV and fluences ranging from 2 x 10{sup 16} up to 10{sup 17} cm{sup -2}. The implantation induced defects observed by conventional and high resolution cross section electron microscopy were found to be essentially cavities 10 to 100 nm in size which are faceted mainly along {l_brace}111{r_brace}, but also along {l_brace}110{r_brace} and {l_brace}100{r_brace} planes. The cavities are located at the sample depth predicted by the transport range of ions in matter simulation. Secondary ion mass spectroscopy profiles exhibit a shouldered shape with a maximum at the projected range. They demonstrate that the cavities are very efficient sinks for Au atoms; the shoulder of the profile could be related to the presence of smaller cavities and dislocations in the vicinity of the projected range. Gold concentration in the cavity area was below the detection limit of the energy dispersive spectroscopy technique, but both Cu and Ni contamination gave rise to silicides and could be chemically analysed. Cu{sub 3}Si precipitates have grown in cavities as already reported in the literature, while NiSi{sub 2} precipitates were observed for the first time in cavities. (orig.)

  2. Influence of pH on the survival of Dictyosphaerium chlorelloides populations living in aquatic environments highly contaminated with chromium.

    Science.gov (United States)

    Pereira, María; Bartolomé, M Carmen; Sánchez-Fortún, Sebastián

    2013-12-01

    The accommodation of photosynthetic organisms to adverse conditions, such as pH changes in the aquatic environment, and their response to aquatic pollutants is essential to develop future biosensors. The present study reports the ability of both Cr(VI)-sensitive and tolerant Dyctiosphaerium chlorelloides strains to live in aqueous solutions highly contaminated with hexavalent chromium under varying ranges of pH, by the determination of chromium toxic effects on these strains. Studies of cell growth, photosynthetic quantum yield and gross photosynthesis rate show that both D. chlorelloides strains are able to survive in alkaline and moderately acidified (pH 4.25) aquatic environments. Below this pH value cell populations from both strains exposed for short periods of time to Cr(VI) showed alterations in the three parameters studied. There were no significant differences comparing the response of both strains at pH change in the culture medium. However, Cr(VI)-tolerant strain exhibits a better fit to maintain cell growth than Cr(VI)-sensitive strain when both were subjected to pH 4.25 in the culture medium. The absence of significant differences in photosynthetic activity results for both strains suggests that the lower sensitivity exhibited by Cr(VI)-tolerant strain would be due to cellular morphological changes rather than changes in cellular activity. © 2013 Published by Elsevier Inc.

  3. Assessment of nonpoint-source contamination of the High Plains Aquifer in south-central Kansas, 1987

    Science.gov (United States)

    Helgesen, John O.; Stullken, Lloyd E.; Rutledge, A.T.

    1994-01-01

    Ground-water quality was assessed in a 5,000-square-mile area of the High Plains aquifer in south-central Kansas that is susceptible to nonpoint-source contamination from agricultural and petroleum-production activities. Of particular interest was the presence of agricultural chemicals and petroleum-derived hydrocarbons that might have been associated with brines that formerly were disposed into unlined ponds. Random sampling of ground water was done within a framework of discrete land-use areas (irrigated cropland, petroleum-production land containing former brine-disposal ponds, and undeveloped rangeland) of 3-10 square miles. Although true baseline water-quality conditions probably are rare, in this region they are represented most closely by ground water in areas of undeveloped rangeland. The sampling design enabled statistical hypothesis testing, using nonparametric procedures, of the effects of land use, unsaturated-zone lithology, and type of well sampled. Results indicate that regional ground-water quality has been affected by prevailing land-use activities, as shown by increased concentrations of several inorganic constituents. Ground water beneath irrigated cropland was characterized by significantly larger concentrations of hardness, alkalinity, calcium, magnesium, potassium, fluofide, and nitrite plus nitrate than was water beneath undeveloped rangeland. Few nondegraded pesticides were detected in the aquifer, probably because of degradation and sorption. Atrazine was the most common, but only in small concentrations. round water beneath petroleum-production land was characterized by significantly larger concentrations of hardness, alkalinity, dissolved solids, sodium, and chloride than was water beneath undeveloped rangeland. Nonpoint-source contamination by oil-derived hydrocarbons was not discernible. The occurrences of trace organic compounds were similar between petroleum-production land and undeveloped rangeland, which indicates a natural origin

  4. Abundance, activity, and diversity of archaeal and bacterial communities in both uncontaminated and highly copper-contaminated marine sediments.

    Science.gov (United States)

    Besaury, Ludovic; Ghiglione, Jean-François; Quillet, Laurent

    2014-04-01

    We analyzed the impact of copper mine tailing discharges on benthic Archaea and Bacteria around the city of Chanaral in northern Chile. Quantitative PCR (Q-PCR) showed that the bacteria dominated the prokaryotic community at both sites, but only the bacteria showed a decrease in abundance in the copper-contaminated site. Q-PCR on reverse transcripts indicated a higher activity of both bacterial and archaeal communities in the contaminated site, suggesting an adaptation of the two communities to copper. This hypothesis was reinforced by the concomitant augmentation of the copper-resistant copA gene coding for a P-type ATP-ase pump in the contaminated site. The metabolically active bacterial community of the contaminated site was dominated by Gammaproteobacteria related to Ectothiorhodospiraceae and Chromatiaceae and by Alphaproteobacteria phylum related to Rhodobacteraceae. The metabolically active archaeal community was dominated by one lineage belonging to unclassified Euryarchaeota and to methanogenic Archaea.

  5. Percentage of probability of nonpoint-source nitrate contamination of recently recharged ground water in the High Plains aquifer

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents the percentage of probability of nonpoint-source nitrate contamination (greater than the proposed background concentration of 4...

  6. Preparation of free-standing diamond films for high frequency SAW devices

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-min; XIA Yi-ben; WANG Lin-jun; SU Qing-feng; ZHAO Ping; XU Run; PENG Hong-yan; SHI Wei-min

    2006-01-01

    Free-standing diamond films were prepared by hot filament chemical vapor deposition (HFCVD) method under different conditions. Inter-digital transducers (IDTs) were formed on the nucleation sides of free-standing diamond films by photolithography technique. Then piezoelectric ZnO films were deposited by radio-frequency(RF) reactive magnetron sputtering to obtain the ZnO/diamond film structures. Surface morphologies of the nucleation sides and the IDTs were characterized by means of scanning electron microscopy (SEM),atomic force microscope (AFM) and optical microscopy. The results indicate that the surfaces of nucleation sides are very smooth and the IDTs are of high quality without discontinuity and short circuit phenomenon. Raman spectra show the sharp diamond feature peak at about 1 334 cm-1 and the small amount of non-diamond carbon in the nucleation side. X-ray diffraction (XRD) patterns of the structure of ZnO/diamond films show a strong diffraction peak of ZnO (002),which indicates that as-sputtered ZnO films are highly c-axis oriented.

  7. Facile preparation of reduced graphene oxide - ruthenium oxide nanocomposite electrodes for high-performance supercapacitors

    Science.gov (United States)

    Amir, Fatima; Pham, Viet; Dickerson, James; Winthrop University Team; CFN-Brookhaven National Lab Team

    2015-03-01

    Herein we report a facile approach of synthesis of graphene oxide (GO) sheets modified with ruthenium oxide (RuO2) nanoparticles, followed by a reduction of graphene oxide in an alkaline medium. The as-prepared reduced graphene oxide (rGO)/ruthenium oxide (RuO2) nanocomposite was used for the fabrication of a symmetric supercapacitor. The specific capacitance and charge-discharge periods of the supercapacitor were found to be dependent on both the structural and morphological properties, and the electrolytes used. Surface morphology analysis using scanning electron microscopy (SEM) shows the RuO2 nanoparticles decorating rGO sheets, comprising a highly porous surface. Structural analysis obtained by x-ray diffraction (XRD) revealed an amorphous structure that is necessary to achieve a high cycling rate capability. The electrochemical properties of rGO/RuO2 were measured in a two electrodes system, using two different electrolytes: H2SO4andNa2SO4. The specific capacitance of rGO/RuO2 in H2SO4 was found to be 318 F/g, and is much higher than that of Na2SO4 (184 F/g).

  8. Characteristics of high-quality HfSiON gate dielectric prepared by physical vapour deposition

    Institute of Scientific and Technical Information of China (English)

    Xu Gao-Bo; Xu Qiu-Xia

    2009-01-01

    This paper presents a method using simple physical vapour deposition to form high-quality hafnium silicon oxyni-tride (HfSiON) on ultrathin SiO2 buffer layer. The gate dielectric with 10A (1/A = 0.1 nm) equivalent oxide thickness is obtained. The experimental results indicate that the prepared HfSiON gate dielectric exhibits good physical and electrical characteristics, including very good thermal stability up to 1000℃, excellent interface properties, high dielec-tric constant (k = 14) and low gate-leakage current (Ig= 1.9×10-3 A/cm2@Vg = Vfb-1V for EOT of 10A). TaN metal gate electrode is integrated with the HfSiON gate dielectric.The effective work function of TaN on HfSiON is 4.3eV, meeting the requirements of NMOS for the metal gate. And, the impacts of sputtering ambient and annealing temperature on the electrical properties of HfSiON gate dielectric are investigated.

  9. Antimicrobial brass coatings prepared on poly(ethylene terephthalate) textile by high power impulse magnetron sputtering.

    Science.gov (United States)

    Chen, Ying-Hung; Wu, Guo-Wei; He, Ju-Liang

    2015-03-01

    The goal of this work is to prepare antimicrobial, corrosion-resistant and low-cost Cu65Zn35 brass film on poly(ethylene terephthalate) (PET) fabric by high-power impulse magnetron sputtering (HIPIMS), which is known to provide high-density plasma, so as to generate a strongly adherent film at a reduced substrate temperature. The results reveal that the brass film grows in a layer-plus-island mode. Independent of their deposition time, the obtained films retain a Cu/Zn elemental composition ratio of 1.86 and exhibit primarily an α copper phase structure. Oxygen plasma pre-treatment for 1min before coating can significantly increase film adhesion such that the brass-coated fabric of Grade 5 or Grade 4-5 can ultimately be obtained under dry and wet rubbing tests, respectively. However, a deposition time of 1min suffices to provide effective antimicrobial properties for both Staphylococcus aureus and Escherichia coli. As a whole, the feasibility of using such advanced HIPIMS coating technique to develop durable antimicrobial textile was demonstrated.

  10. Preparative Separation of Phenolic Compounds from Halimodendron halodendron by High-Speed Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    Zhu Yu

    2010-08-01

    Full Text Available Three phenolic compounds, p-hydroxybenzoic acid (1, isorhamnetin-3-O-β-D-rutinoside (2, and 3,3'-di-O-methylquercetin (5, along with a phenolic mixture were successfully separated from the ethyl acetate crude extract of Halimodendron halodendron by high-speed counter-current chromatography (HSCCC with chloroform-methanol-water-acetic acid (4:3:2:0.05, v/v as the two-phase solvent system. The phenolic mixture from HSCCC was further separated by preparative HPLC and purified by Sephadex LH-20 to afford quercetin (3 and 3-O-methylquercetin (4. Seven hundred mg of ethyl acetate crude extract was separated by HSCCC to obtain six fractions which were then analyzed by high performance liquid chromatography (HPLC. The HSCCC separation obtained total of 80 mg of the mixture of quercetin (3 and 3-O-methylquercetin (4 (26.43% and 71.89%, respectively in fraction 2, 14 mg of 3,3'-di-O-methylquercetin (5 at 95.14% of purity in fraction 3, 15 mg of p-hydroxybenzoic acid (1 at 92.83% of purity in fraction 5, 12 mg of isorhamnetin-3-O-β-D-rutinoside (2 at 97.99% of purity in fraction 6. This is the first time these phenolic compounds have been obtained from H. halodendron, and their chemical structures identified by means of physicochemical and spectrometric analysis.

  11. Hydrogen in-situ refining method for preparing high purity gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guoling [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Li, Li [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Fu, Kai [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Wang, Chongyun [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Zheng, Jie [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Xu, Li [State Grid Smart Grid Research Institute, Future Science& Technology Park, Changping, Beijing 102211 (China); Tian, Wenhuai [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Li, Xingguo, E-mail: xgli@pku.edu.cn [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)

    2015-11-05

    The removal of non-metallic impurities, especially oxygen and nitrogen, from the rare-earth metal gadolinium (Gd) is challenging, due to their strong affinity to Gd metal. Herein we present an effective approach to prepare high purity Gd via a novel hydrogen in-situ refining method. The final concentrations of oxygen and nitrogen could be reduced to 30 and 19 mass ppm, respectively. The changes of lattice parameters were derived from XRD; enthalpy values and gaseous speciation associated with the gas–solid physiochemical reactions were determined through a combination of DSC/MS measurements and thermodynamic calculations. The results show that oxygen and nitrogen can be efficiently removed by degassing Gd with dissolved hydrogen. The underlying mechanism for the refinement is discussed systematically in this paper. - Highlights: • Hydrogen can shuttle gadolinium freely at high temperature. • The concentration of O and N dropped to 30 ppm and 19 ppm, respectively. • The hydrogen content could finally decrease to 17 ppm. • Hydrogen, water and ammonia signals can be detected successfully. • This method is environment friendly and no other recontaminations.

  12. Preparation and characterization of modified starch granules with high hydrophobicity and flowability.

    Science.gov (United States)

    Chang, Fengdan; He, Xiaowei; Fu, Xiong; Huang, Qiang; Qiu, Yaofang

    2014-01-01

    Normal cornstarch (NC) was chemically modified by octenylsuccinic anhydride (OSA) and Al2(SO4)3. The effects of the concentration of NaOH, OSA, and Al2(SO4)3 on the properties of modified starch(OS-starch-Al) were investigated. The OS-starch-Al was characterized by repose angle, activation index, inductively coupled plasma-atomic emission spectrometry (ICP-OES), light microscopy, SEM, FT-IR, and (27)Al NMR. The results showed that pH 4 was the optimum condition for Al(3+) cross-linking with OS-starch and for obtaining high flowability and hydrophobicity. When the concentration of OSA and Al2(SO4)3 was 2%, the OS-starch-Al was characterized by high flowability. A concentration of 4% OSA and Al2(SO4)3 yielded the highest activation index. The moisture content affected the flowability of native NC, but had a minor effect on OS-starch-Al. SEM and polarized microscopy revealed that the modification had slight effects on the crystalline structure and morphology of NC. During the preparation, some dust particles functioning as flow additives were produced on the surface of starch granules. The results of FT-IR, ICP-OES, and (27)Al NMR confirmed the formation of ester group and the cross-link with Al(3+). Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. A modified coaxial electrospinning for preparing fibers from a high concentration polymer solution

    Directory of Open Access Journals (Sweden)

    2011-08-01

    Full Text Available A new process technology modified from conventional coaxial electrospinning process has been developed to prepare polymer fibers from a high concentration solution. This process involves a pure solvent concentrically surrounding polymer fluid in the spinneret. The concentric spinneret was constructed simply by inserting a metal needle through a high elastic silica gel tube. Two syringe pumps were used to drive the core polymer solution and the sheath solvent. Using polyvinylpyrrolidone (PVP as the polymer model, which normally has an electrospinnable concentration of 10% w/v in ethanol, it was possible to electrospin 35% w/v of PVP in the same solvent, when pure N, N-dimethylacetamide (DMAc was used as sheath fluid. The resultant fibers have a smooth surface morphology and good structural uniformity. The diameter of the fibers was 2.0±0.25 µm when the DMAc-to-polymer-solution flow rate ratio was set as 0.1. The process technology reported here opens a new window to tune the polymer fibers obtained by the electrospinning, and is useful for improving productivity of the electrospinning process.

  14. Evaluation of sustained release suppositories prepared with fatty base including solid fats with high melting points.

    Science.gov (United States)

    Takatori, Toshihito; Shimono, Norihito; Higaki, Kazutaka; Kimura, Toshikiro

    2004-07-08

    To prepare the sustained release suppositories, solid fats such as polyglycerol ester of fatty acids (PGEFs) or beeswax were utilized with a fatty suppository base, Witepsol H15. PGEFs such as decaglycerol heptabehenate (HB750) and hexaglycerol pentastearate (PS500), and beeswax have relatively high melting points. The addition of PGEFs or beeswax to Witepsol H15 increased the apparent viscosity of suppository bases at 37 degrees C without any large change in the melting point of Witepsol H15. Moreover, the apparent viscosity of a mixed base with HB750, PS500 or beeswax at 37 degrees C was significantly correlated with the amount of each solid fat in a mixed base. The release of acetaminophen (AAP), a model drug, from suppositories was delayed by HB750, PS500 or beeswax, and an excellent correlation was observed between the apparent viscosity of these mixed bases and Higuchi's rate constants in each mixed base suppository, suggesting that these solid fats could regulate the drug release from the mixed base suppositories by changing their viscosity. In the in vivo absorption study in rats, several suppositories made from Witepsol H15-HB750 or Witepsol H15-beeswax mixed bases prolonged the rectal absorption of AAP without reducing AUC. In conclusion, by using solid fats such as HB750 and beeswax with relatively high melting points, it is possible to control the rate of drug release from fatty base suppositories for maintaining the plasma concentration of drugs for longer time periods.

  15. Purification of Ovine Respiratory Complex I Results in a Highly Active and Stable Preparation.

    Science.gov (United States)

    Letts, James A; Degliesposti, Gianluca; Fiedorczuk, Karol; Skehel, Mark; Sazanov, Leonid A

    2016-11-18

    NADH-ubiquinone oxidoreductase (complex I) is the largest (∼1 MDa) and the least characterized complex of the mitochondrial electron transport chain. Because of the ease of sample availability, previous work has focused almost exclusively on bovine complex I. However, only medium resolution structural analyses of this complex have been reported. Working with other mammalian complex I homologues is a potential approach for overcoming these limitations. Due to the inherent difficulty of expressing large membrane protein complexes, screening of complex I homologues is limited to large mammals reared for human consumption. The high sequence identity among these available sources may preclude the benefits of screening. Here, we report the characterization of complex I purified from Ovis aries (ovine) heart mitochondria. All 44 unique subunits of the intact complex were identified by mass spectrometry. We identified differences in the subunit composition of subcomplexes of ovine complex I as compared with bovine, suggesting differential stability of inter-subunit interactions within the complex. Furthermore, the 42-kDa subunit, which is easily lost from the bovine enzyme, remains tightly bound to ovine complex I. Additionally, we developed a novel purification protocol for highly active and stable mitochondrial complex I using the branched-chain detergent lauryl maltose neopentyl glycol. Our data demonstrate that, although closely related, significant differences exist between the biochemical properties of complex I prepared from ovine and bovine mitochondria and that ovine complex I represents a suitable alternative target for further structural studies.

  16. Experimental Preparation and Numerical Simulation of High Thermal Conductive Cu/CNTs Nanocomposites

    Directory of Open Access Journals (Sweden)

    Muhsan Ali Samer

    2014-07-01

    Full Text Available Due to the rapid growth of high performance electronics devices accompanied by overheating problem, heat dissipater nanocomposites material having ultra-high thermal conductivity and low coefficient of thermal expansion was proposed. In this work, a nanocomposite material made of copper (Cu reinforced by multi-walled carbon nanotubes (CNTs up to 10 vol. % was prepared and their thermal behaviour was measured experimentally and evaluated using numerical simulation. In order to numerically predict the thermal behaviour of Cu/CNTs composites, three different prediction methods were performed. The results showed that rules of mixture method records the highest thermal conductivity for all predicted composites. In contrast, the prediction model which takes into account the influence of the interface thermal resistance between CNTs and copper particles, has shown the lowest thermal conductivity which considered as the closest results to the experimental measurement. The experimentally measured thermal conductivities showed remarkable increase after adding 5 vol.% CNTs and higher than the thermal conductivities predicted via Nan models, indicating that the improved fabrication technique of powder injection molding that has been used to produced Cu/CNTs nanocomposites has overcome the challenges assumed in the mathematical models.

  17. Solvent-free preparation of high-toughness epoxy--SWNT composite materials.

    Science.gov (United States)

    González-Domínguez, Jose M; Ansón-Casaos, Alejandro; Díez-Pascual, Ana M; Ashrafi, Behnam; Naffakh, Mohammed; Backman, David; Stadler, Hartmut; Johnston, Andrew; Gómez, Marian; Martínez, M Teresa

    2011-05-01

    Multicomponent nanocomposite materials based on a high-performance epoxy system and single-walled carbon nanotubes (SWNTs) have been prepared. The noncovalent wrapping of nitric acid-treated SWNTs with a PEO-based amphiphilic block copolymer leads to a highly disaggregated filler with a boosted miscibility in the epoxy matrix, allowing its dispersion without organic solvents. Although direct dispersion of acid-treated SWNTs results in modestly improved epoxy matrix mechanical properties, the incorporation of wrapped SWNTs produces a huge increase in toughness (276% improvement at 0.5 wt % loading) and impact strength (193% at 0.5 wt % loading) with no detrimental effect on the elastic properties. A synergistic effect between SWNTs and the block copolymer is revealed on the basis of tensile and impact strength results. Atomic force microscopy has been applied, obtaining stiffness mappings that identify nanostructure features responsible of the dynamic mechanical behavior. The electrical percolation threshold is greatly reduced, from 0.31 to 0.03 wt % SWNTs when block copolymer-wrapped SWNTs are used, and all the measured conductivity values increased up to a maximum of 7 orders of magnitude with respect to the baseline matrix (1 wt % wrapped-SWNTs loading). This approach provides an efficient way to disperse barely dispersible SWNTs without solvents into an epoxy matrix, and to generate substantial improvements with small amounts of SWNTs.

  18. LLW disposal wasteform preparation in the UK: the role of high force compaction

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, L. F.; Fearnley, I. G. [British Nuclear Fuels Ltd., Sellafield (United Kingdom)

    1991-07-01

    British Nuclear Fuels plc (BNFL) owns and operates the principal UK solid low level radioactive waste (LLW) disposal site. The site is located at Drigg in West Cumbria some 6 km to the south east of BNFL's Sellafield reprocessing complex. Sellafield is the major UK generator of LLW, accounting for about 85% of estimated future arisings of raw (untreated, unpackaged) waste. Non-Sellafield consignors to the Drigg site include other BNFL production establishments, nuclear power stations, sites of UKAEA, Ministry of Defence facilities, hospitals, universities, radioisotope production sites and various other industrial organisations. In September 1987, BNFL announced a major upgrade of operations at the Drigg site aimed at improving management practices, the efficiency of space utilisation and enhancing the visual impact of disposal operations. During 1989 a review of plans for compaction and containerisation of Sellafield waste identified that residual voidage in ISO freight containers could be significant even after the introduction of compaction. Subsequent studies which examined a range of compaction and packaging options concluded that the preferred scheme centred on the use of high force compaction (HFC) of compactable waste, and grouting to take up readily accessible voidage in the wasteform. The paper describes the emergence of high force compaction as the preferred scheme for wasteform preparation and subsequent benefits against the background of the overall development of Low Level Waste disposal operations at Drigg.

  19. PREPARING NANO-CRYSTALLINE La DOPED WC/Co POWDER BY HIGH ENERGY BALL MILLING

    Institute of Scientific and Technical Information of China (English)

    S. Liu; D.Q. Yi; Y.X. Li; D. Zou

    2002-01-01

    The La doped WC/Co powder was prepared by high energy ball milling. The changesof crystal structure, micrograph and defect of the powder were investigated by means ofXRD (X-ray diffraction), SEM (scanning electron microscope) and DTA (differentialthermal analysis). The results show that adding trace La element into carbides iseffective to minish the grain size of WC/Co powder. The La doped carbides powderwith grain size of 30nm can be obtained after 1Oh ball milling. The XRD peak of Cophase disappeared after 20h ball milling, which indicated solid solution (or secondarysolid solution) of Co phase in WC phase. The La doped powder with grain size of1Ohm is obtained after 30h ball milling. A peak of heat release at the temperatureof 470℃ was emerged in DTA curve within the range of heating temperature, whichshowed that the crystal structure relaxation of the powder appeared in the process ofhigh energy ball milling. After consolidated the La doped WC/Co alloy by high energyball milling exhibits ultra-fine grain Sizes and better mechanical properties.

  20. Preparation and Characterization of High Surface Area Activated Carbon Fibers from Lignin

    Directory of Open Access Journals (Sweden)

    Jian Lin

    2016-10-01

    Full Text Available Activated carbon fibers (ACFs were successfully prepared from softwood lignin, which was isolated with polyethylene glycol 400 (PEG-400 as a solvolysis reagent, by water steam activation. The pore characterization and adsorption property of ACFs were investigated. The results showed that all the ACFs with more micropores exhibited high specific surface area and total pore volume which increased with the activation time prolonging; the highest ones were around 3100 m2/g and 1.5 mL/g, respectively. The specific surface area and total pore volume were much larger than those of other types of lignin-based ACFs and activated charcoal. Besides, with increasing activation time, the amount of graphitic carbon, which was the main compound on the surface of ACFs, decreased, while the amount of functional groups containing C–O slightly increased. In addition, the adsorption capacity of ACFs for methylene blue was highly increased as the activation time increased. Accordingly, lignin isolated with PEG is a promising precursor for ACF production.

  1. Optimized Expression and Purification for High-Activity Preparations of Algal [FeFe]-Hydrogenase

    Energy Technology Data Exchange (ETDEWEB)

    Yacoby, I.; Tegler, L. T.; Pochekailov, S.; Zhang, S.; King, P. W.

    2012-04-01

    Recombinant expression and purification of metallo-enzymes, including hydrogenases, at high-yields is challenging due to complex, and enzyme specific, post-translational maturation processes. Low fidelities of maturation result in preparations containing a significant fraction of inactive, apo-protein that are not suitable for biophysical or crystallographic studies. We describe the construction, overexpression and high-yield purification of a fusion protein consisting of the algal [2Fe2S]-ferredoxin PetF (Fd) and [FeFe]-hydrogenase HydA1. The maturation of Fd-HydA1 was optimized through improvements in culture conditions and media components used for expression. We also demonstrated that fusion of Fd to the N-terminus of HydA1, in comparison to the C-terminus, led to increased expression levels that were 4-fold higher. Together, these improvements led to enhanced HydA1 activity and improved yield after purification. The strong binding-affinity of Fd for DEAE allowed for two-step purification by ion exchange and StrepTactin affinity chromatography. In addition, the incorporation of a TEV protease site in the Fd-HydA1 linker allowed for the proteolytic removal of Fd after DEAE step, and purification of HydA1 alone by StrepTactin. In combination, this process resulted in HydA1 purification yields of 5 mg L{sup -1} of culture from E. coli with specific activities of 1000 U (U = 1 {micro}mol hydrogen evolved mg{sup -1} min{sup -1}). The [FeFe]-hydrogenases are highly efficient enzymes and their catalytic sites provide model structures for synthetic efforts to develop robust hydrogen activation catalysts. In order to characterize their structure-function properties in greater detail, and to use hydrogenases for biotechnological applications, reliable methods for rapid, high-yield expression and purification are required.

  2. Preparation of 2D crystals of membrane proteins for high-resolution electron crystallography data collection.

    Science.gov (United States)

    Abeyrathne, Priyanka D; Chami, Mohamed; Pantelic, Radosav S; Goldie, Kenneth N; Stahlberg, Henning

    2010-01-01

    Electron crystallography is a powerful technique for the structure determination of membrane proteins as well as soluble proteins. Sample preparation for 2D membrane protein crystals is a crucial step, as proteins have to be prepared for electron microscopy at close to native conditions. In this review, we discuss the factors of sample preparation that are key to elucidating the atomic structure of membrane proteins using electron crystallography.

  3. Remediation of highly contaminated soils from an industrial site by employing a combined treatment with exogeneous humic substances and oxidative biomimetic catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Sannino, Filomena, E-mail: fsannino@unina.it [Dipartimento di Agraria, Università di Napoli “Federico II”, Via Università 100, 80055 Portici (Italy); Spaccini, Riccardo [Dipartimento di Agraria, Università di Napoli “Federico II”, Via Università 100, 80055 Portici (Italy); Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l’Ambiente, l’Agro-Alimentare ed i Nuovi Materiali (CERMANU), Via Università 100, 80055 Portici (Italy); Savy, Davide [Dipartimento di Agraria, Università di Napoli “Federico II”, Via Università 100, 80055 Portici (Italy); Piccolo, Alessandro [Dipartimento di Agraria, Università di Napoli “Federico II”, Via Università 100, 80055 Portici (Italy); Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l’Ambiente, l’Agro-Alimentare ed i Nuovi Materiali (CERMANU), Via Università 100, 80055 Portici (Italy)

    2013-10-15

    Highlights: • Remediation of two polluted soils from a highly contaminated industrial site in Italy. • Restoration of soil quality by introducing additional carbon into polluted soil with humic matter amendments. • Detoxification of contaminants by covalent binding to humic molecules. • Prevention of environmental transport of pollutants. -- Abstract: Remediation of two polluted soils from a northern Italian industrial site heavily contaminated with organic contaminants was attempted here by subjecting soils first to addition with an exogenous humic acid (HA), and, then, to an oxidation reaction catalyzed by a water-soluble iron-porphyrin (FeP). An expected decrease of detectable organic pollutants (>50%) was already observed when soils were treated only with the H{sub 2}O{sub 2} oxidant. This reduction was substantially enhanced when oxidation was catalyzed by iron-porphyrin (FeP + H{sub 2}O{sub 2}) and the largest effect was observed for the most highly polluted soil. Even more significant was the decrease in detectable pollutants (70–90%) when soils were first amended with HA and then subjected to the FeP + H{sub 2}O{sub 2} treatment. This reduction in extractable pollutants after the combined HA + FeP + H{sub 2}O{sub 2} treatment was due to formation of covalent C-C and C-O-C bonds between soil contaminants and amended humic molecules. Moreover, the concomitant detection of condensation products in soil extracts following FeP addition confirmed the occurrence of free-radical coupling reactions catalyzed by FeP. These findings indicate that a combined technique based on the action of both humic matter and a metal-porhyrin catalyst, may become useful to quantitatively reduce the toxicity of heavily contaminated soils and prevent the environmental transport of pollutants.

  4. Recommendations for the hygienic preparation of infant formula in powder form

    OpenAIRE

    Federal Institute for Risk Assessment

    2012-01-01

    The hygienic requirements for infant formula are very high. For this reason, infections caused by pathogenic germs are rare. Nevertheless, in exceptional cases, contamination of the baby food may occur, because many types of germs survive the manufacturing process for food in powder form. They can then multiply in the prepared food. In addition, baby food can be contaminated with germs via spoons, teats or baby bottles when the formula is prepared. Against this background, the Federal Institu...

  5. Contaminated water treatment

    Science.gov (United States)

    Gormly, Sherwin J. (Inventor); Flynn, Michael T. (Inventor)

    2010-01-01

    Method and system for processing of a liquid ("contaminant liquid") containing water and containing urine and/or other contaminants in a two step process. Urine, or a contaminated liquid similar to and/or containing urine and thus having a relatively high salt and urea content is passed through an activated carbon filter to provide a resulting liquid, to remove most of the organic molecules. The resulting liquid is passed through a semipermeable membrane from a membrane first side to a membrane second side, where a fortified drink having a lower water concentration (higher osmotic potential) than the resulting liquid is positioned. Osmotic pressure differential causes the water, but not most of the remaining inorganic (salts) contaminant(s) to pass through the membrane to the fortified drink. Optionally, the resulting liquid is allowed to precipitate additional organic molecules before passage through the membrane.

  6. Associations between organohalogen concentrations and transcription of thyroid-related genes in a highly contaminated gull population.

    Science.gov (United States)

    Técher, Romy; Houde, Magali; Verreault, Jonathan

    2016-03-01

    A number of studies have reported altered circulating thyroid hormone levels in birds exposed either in controlled settings or in their natural habitat to ubiquitous organohalogen compounds including organochlorines (OCs) and polybrominated diphenyl ether (PBDE) flame retardants. However, limited attention has been paid to underlying homeostatic mechanisms in wild birds such as changes in the expression of genes in the hypothalamic-pituitary-thyroid (HPT) axis. The objective of the present study was to investigate the relationships between hepatic concentrations of major organohalogens (PBDEs and OCs), and circulating thyroid hormone (free and total thyroxine (T4) and triiodothyronine (T3)) levels and transcription of 14 thyroid-related genes in three tissues (thyroid, brain, and liver) of an urban-adapted bird exposed to high organohalogen concentrations in the Montreal area (QC, Canada), the ring-billed gull (Larus delawarensis). Positive correlations were found between liver concentrations of several polychlorinated biphenyls (PCBs), PBDEs as well as chlordanes and total plasma T4 levels. Hepatic concentrations of several PBDEs were negatively correlated with mRNA levels of deiodinase type 3, thyroid peroxidase, and thyroid hormone receptor β (TRβ) in the thyroid gland. Liver PCB (deca-CB) correlated positively with mRNA levels of sodium-iodide symporter and TRα. In brain, concentrations of most PBDEs were positively correlated with mRNA levels of organic anion transporter protein 1C1 and transthyretin, while PCBs positively correlated with expression of TRα and TRβ as well as deiodinase type 2. These multiple correlative linkages suggest that organohalogens operate through several mechanisms (direct or compensatory) involving gene transcription, thus potentially perturbing the HPT axis of this highly organohalogen-contaminated ring-billed gull population. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Are high energy proton beams ideal for AB-BNCT? A brief discussion from the viewpoint of fast neutron contamination control.

    Science.gov (United States)

    Lee, Pei-Yi; Liu, Yuan-Hao; Jiang, Shiang-Huei

    2014-06-01

    High energy proton beam (>8MeV) is favorable for producing neutrons with high yield. However, the produced neutrons are of high energies. These high energy neutrons can cause severe fast neutron contamination and degrade the BNCT treatment quality if they are not appropriately moderated. Hence, this study aims to briefly discuss the issue, from the viewpoint of fast neutron contamination control, whether high energy proton beam is ideal for AB-BNCT or not. In this study, D2O, PbF4, CaF2, and Fluental(™) were used standalone as moderator materials to slow down 1-, 6-, and 10-MeV parallelly incident neutrons. From the calculated results, we concluded that neutrons produced by high energy proton beam could not be easily moderated by a single moderator to an acceptable contamination level and still with reasonable epithermal neutron beam intensity. Hence, much more complicated and sophisticated designs of beam shaping assembly have to be developed when using high energy proton beams.

  8. Preparation and investigation of nano-AlN lubricant with high performance

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Yu; Tao, Yuxiao; Wang, Biaobing [School of Materials Science and Engineering, Changzhou University, Changzhou 201326 (China); Tai, Yanlong, E-mail: ytai@ucdavis.edu [Department of Biomedical Engineering, University of California Davis, Davis, CA 95616 (United States)

    2014-09-15

    A new kind of macromolecular coupling agent (LMW-a-PP-g-MAH) of maleic anhydride (MAH) onto low-molecular-weight atactic polypropylene (LMW-a-PP) was synthesized according to molecular design and was used as modifier for surface modification of nano-Aluminum nitride (AlN) by a high-pressure homogenization (HPH) process. IR was conducted to confirm the chemical structure of the step products of LMW-a-PP-g-MAH. The availability as a modifier for surface modification of nano-AlN was distinguished by Fourier transform infrared spectroscopy (FTIR), particle size analysis, transmission electron microscope (TEM), thermogravimetric analysis (TGA), contact angle experiments and the dispersion stability in dimethylbenzene and Greatwall lubrication oil. It can be inferred that the optimal loading is 10 wt. %–12 wt. % of LMW-a-PP-g-MAH to modify nano-AlN particles. Nano-AlN lubricating composite materials (LMW-a-PP-g-MAH-AlN) was used to improve the antifriction performance and the load capability of Greatwall lubrication oil, and maximum non-seizure load (P{sub B}) can increase highly from 1000 N to 1490 N when the loading is 0.3 wt. %. - Highlights: • Design and synthesis of macromolecular coupling agent (a-PP-g-MAH). • Surface modification and characterization of nano-AlN by HPH process. • Preparation and investigation of nano-AlN/lubricating oil with high performance.

  9. Highly hydrophilic ultra-high molecular weight polyethylene powder and film prepared by radiation grafting of acrylic acid

    Science.gov (United States)

    Wang, Honglong.; Xu, Lu.; Li, Rong.; Pang, Lijuan.; Hu, Jiangtao.; Wang, Mouhua.; Wu, Guozhong.

    2016-09-01

    The surface properties of ultra-high molecular weight polyethylene (UHMWPE) are very important for its use in engineering or composites. In this work, hydrophilic UHMWPE powder and film were prepared by γ-ray pre-irradiation grafting of acrylic acid (AA) and further neutralization with sodium hydroxide solution. Variations in the chemical structure, grafting yield and hydrophilicity were investigated and compared. FT-IR and XPS analysis results showed that AA was successfully grafted onto UHMWPE powder and film; the powder was more suitable for the grafting reaction in 1 wt% AA solution than the film. Given a dose of 300 kGy, the grafting yield of AA was ∼5.7% for the powder but ∼0.8% for the film under identical conditions. Radiation grafting of a small amount of AA significantly improved the hydrophilicity of UHMWPE. The water contact angle of the UHMWPE-g-PAA powder with a grafting yield of AA at ∼5.7% decreased from 110.2° to 68.2°. Moreover, the grafting powder (UHMWPE-g-PAA) exhibited good dispersion ability in water.

  10. Purification of six lignans from the stems of Schisandra chinensis by using high-speed counter-current chromatography combined with preparative high-performance liquid chromatography.

    Science.gov (United States)

    Zhu, Lijie; Li, Bin; Liu, Xiuying; Huang, Guohui; Meng, Xianjun

    2015-11-01

    A method for the preparative purification of lignans from Schisandra chinensis was established using a combination of high-speed counter-current chromatography (HSCCC) and preparative high-performance liquid chromatography (HPLC). The crude extracts obtained from S. chinensis by using 70% ethanol were separated on a macroporous resin column and then eluted with a graded ethanol series. A two-phase solvent system consisting of n-hexane-ethyl acetate-methanol-water (1:1:1:1, v/v) was used for HSCCC, and a mobile phase of acetonitrile-water (50:50, v/v) was used for preparative HPLC. The results obtained using HSCCC were compared with those obtained using preparative HPLC, and their advantages were further integrated to improve the separation efficiency. Six known lignans were identified by electrospray ionisation mass spectrometry and (1)H nuclear magnetic resonance (NMR) and (13)C NMR analyses; the purities of all the compounds were more than 91%.

  11. High velocity air microabrasion for conservative tooth preparation: the principle and the clinical procedure.

    Science.gov (United States)

    Feinman, R A

    1995-10-01

    Various technologies within the dental armamentarium are applied to achieve the precise tooth preparations required for the different types of restorations. This article reintroduces the air microabrasion technique, which was first presented in 1945. The popular use of this technique had been postponed, pending the decrease in cost and development of compatible restorative materials to repair the tooth structure. With increased patient demand for less invasive preparation techniques and the decrease of the equipment cost, the use of air microbrasion for tooth preparation has been recognized. The history of the technology, its function, indications, advantages, and limitations are discussed, and a step-by-step clinical procedure is presented. The learning objective of this article is to familiarize the readers with this preparation procedure, enhancing the knowledge of preparation options.

  12. Space-confined preparation of high surface area tungsten oxide and tungsten nitride inside the pores of mesoporous silica SBA-15

    DEFF Research Database (Denmark)

    Meyer, Simon; Beyer, Hans; Köhler, Klaus

    2015-01-01

    For the direct preparation of high surface area nitride materials, a lack of suitable precursors exists. Indirect preparation by gas phase nitridation (e.g. by ammonia) requires high temperatures and often results in sintering. The present work demonstrates that the space-confined preparation of ...

  13. CT colonography in a Korean population with a high residue diet: Comparison between wet and dry preparations

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.H. [Department of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of); Choi, B.I. [Department of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of)]. E-mail: choibi@radcom.snu.ac.kr; Han, J.K. [Department of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Hospital, Seoul (Korea, Republic of); Lee, J.M. [Department of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Hospital, Seoul (Korea, Republic of); Eun, H.W. [Ewha Woman' s University Hospital, Seoul (Korea, Republic of); Lee, J.Y. [Department of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of); Lee, K.H. [Seoul National University Bundang Hospital, Seoul (Korea, Republic of); Han, C.J. [Health Care System, Seoul National University Hospital, Seoul (Korea, Republic of); Choi, Y.H. [Department of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of); Shin, K.-S. [Chungnam National University Hospital, Seoul (Korea, Republic of)

    2006-06-15

    AIM: To compare wet and dry preparation methods for computed tomography colonography (CTC) in terms of preparation quality, interpretation time, and diagnostic performance for polyp detection in a population with a high residue diet. MATERIALS AND METHODS: Eighty-six patients were divided into two groups. Group 1 (n=24) received a wet preparation of 4 l polyethylene glycol (PEG) solution, and group 2 (n=62) received a dry preparation of phosphor-soda. Abnormal findings, including polyps, and the time required to interpret the CTC images in both groups were documented by a radiologist. CTC findings were compared to those of colonoscopy as a reference standard. Two radiologists evaluated the quality of CTC with regard to residual fluid, faeces, and colonic distension using a four-point scale in consensus. Statistical differences for residual fluid, faeces, distensibility on CTC, and interpretation time between the two groups were analysed. The diagnostic performance of CTC in both groups was also compared. RESULTS: One-hundred and ninety polyps in 70 patients were identified using colonoscopy. Regarding the quality of images produced the wet preparation was significantly better than the dry preparation (p<0.05). The average interpretation time was significantly shorter for the wet group (11.7 min) than the dry group (16.4 min) (p<0.05). For per-patient analysis, the positive predictive value (PPV) was significantly better for the wet (100%) than the dry group (79.6%; p=0.025). Sensitivities and PPV for {>=}10 mm polyps were comparable between two groups (p>0.05). CONCLUSION: In a population with a high-residue diet, CTC with wet preparation can be interpreted in a time-efficient manner and is comparable with CTC with dry preparation.

  14. Architectured morphologies of chemically prepared NiO/MWCNTs nanohybrid thin films for high performance supercapacitors.

    Science.gov (United States)

    Gund, Girish S; Dubal, Deepak P; Shinde, Sujata S; Lokhande, Chandrakant D

    2014-03-12

    The preparation of nanostructured metal oxide decorated on multiwalled carbon nanotubes (MWCNTs) nanohybrid films through simple, scalable, additive-free, binderless, and cost-effective route has fascinated significant attention not only in fundamental research areas but also its commercial applications, in order to reduce the growing environmental pollution and the cost of electrode fabrication. Here, we report the fabrication of highly flexible electrode with NiO/MWCNTs nanohybrid thin films directly on stainless steel substrate using successive ionic layer adsorption and reaction (SILAR) method. The impact of ratio of adsorption and reaction cycles on structural, surface areas and electrochemical properties of NiO/MWCNTs nanohybrids was investigated. X-ray diffraction measurements confirm the hybridization and face centered cubic (FCC) crystal structure of NiO in NiO/MWCNTs nanohybrids. In addition, these nanohybrids exhibit excellent surface properties such as uniform surface morphology, good surface area, pore volume, and uniform pore size distribution. The electrochemical tests demonstrate the highest specific capacitance of 1727 F g(-1) at 5 mA cm(-2) of current density with 91% capacitance retention after 2000 cycles. In addition, the Ragone plot confirms the better power and energy densities for all NiO/MWCNTs nanohybrids. The attractive electrochemical capacitive activity revealed by NiO/MWCNTs nanohybrid electrode proposes that it is an auspicious respondent for future energy storage application.

  15. Preparation and characterization of high salts polymer electrolyte based on poly(lithium acrylate)

    Institute of Scientific and Technical Information of China (English)

    TANG Ai-dong; HUANG Ke-long; PAN Chun-yue; LU Cui-hong

    2005-01-01

    Novel polymer electrolytes were prepared by highly mixing poly(lithium acrylate)(PPALi) with eutectic lithium salts of lithium acetate and lithium nitrate.Poly(lithium acrylate) was preparaed by inverse emulsion polymerization from crylic acid and LiOH.Phase transition temperatures were measured for all the eutectic lithium of binary system samples as a function of the concentration of Li(CH3 COO),and the mixtures exhibit the lowest phase transition temperatures of (448±2) K at about 50% (mass fraction) Li(CH3 COO).Thermogravimetry(TG)and X-ray diffraction(XRD) analysis indicate the formation of a novel polymer-salt complex.The highest conductivity(approximately 4.97 ×10-5S·cm-1) is found at room temperature with the electrolyte composition of eutectic mixture of about 80% (mass fraction),poly(lithium acrylate) 20% under quickly cooling condition,which is 150%higher than that under natural cooling condition.

  16. Characterization and Stability Evaluation of Thymoquinone Nanoemulsions Prepared by High-Pressure Homogenization

    Directory of Open Access Journals (Sweden)

    Zaki Tubesha

    2013-01-01

    Full Text Available Despite the pharmacological properties of thymoquinone (TQ, its administration in vivo remains problematic partly due to its poor water solubility, leading to low absorptivity and bioavailability. Hence, the objective of this study is to prepare, characterize, and evaluate the stability of TQ nanoemulsion (TQNE. Conventional emulsion from TQ (TQCE and empty nano- and conventional emulsions from Triolein (TRNE and TRCE are also produced for comparison purposes. The oil-in-water nanoemulsions of TQ and Triolein were produced by high-pressure homogenization. Emulsions were characterized physically by droplet size, polydispersity index, zeta potential, and refractive index. The changes of these parameters in TQNE samples stored for 6 months at 4 and 25°C were not statistically significant (P<0.05. In addition, the initial particle sizes of TQNE and TRNE were 119.6 and 119.5 nm, respectively. Stability studies were also performed for the period of 6 months. At the end of the experiment, the percent of remaining TQ in TQNE at 4, 25, and 40°C was 90.6, 89.1, and 87.4 % respectively. Slower degradation of TQ indicated the chemical stability of TQ in TQNE samples. These results indicated that TQNE is stable over a period of 6 months.

  17. Dispersion Performance of Methanol-Diesel Emulsiifed Fuel Prepared by High Gravity Technology

    Institute of Scientific and Technical Information of China (English)

    Jiao Weizhou; Li Jing; Liu Youzhi; Zhang Qiaoling; Liu Wenli; Xu Chengcheng; Guo Liang

    2014-01-01

    A new continuous process for preparing methanol-diesel emulsified fuel with an Impinging Stream-Rotating Packed Bed is proposed. The droplet size of dispersed phase (methanol) of the emulsiifed fuel has a signiifcant effect on the combustion of methanol-diesel emulsiifed fuel. In this paper, the methanol-diesel emulsiifed fuel uses diesel as the continu-ous phase and methanol as the dispersed phase. The Sauter mean diameter of the dispersed phase of methanol-diesel emulsi-ifed fuel was characterized with microphotography and arithmetic method. The experimental result showed that the Sauter mean diameter of the dispersed phase, which was decreased with the augmentation of the high gravity factor, liquid lfow rate and emulsiifer dosage, was inversely proportional to the methanol content. The Sauter mean diameter of the dispersed phase can be controlled and adjusted in the range of 12-40μm through the change of operating conditions. The correlative expressions of the Sauter mean diameter of emulsiifed fuel were obtained and the calculated values agreed well with the ex-perimental values.

  18. Correlation Between Microstructure and Corrosion Resistance of Magnesium Alloys Prepared by High Strain Rate Rolling

    Science.gov (United States)

    Chen, Jihua; Chen, Guanqing; Yan, Hongge; Su, Bin; Gong, Xiaole; Zhou, Bo

    2017-09-01

    Microstructure and corrosion resistance in Hank's solution of four magnesium alloys (pure Mg, ZK60, Mg-4Zn and Mg-4Zn-0.3Ca) prepared by high strain rate rolling (HSRR) and conventional rolling (CR) are comparatively investigated. The HSRR alloy exhibits better bio-corrosion resistance than the CR alloy. The HSRR ZK60 alloy has finer grains, higher dynamic recrystallization (DRX) extent, lower twin fraction, coarser residual second-phase particles, finer and denser nanometer β 1 precipitates, lower residual compressive stress and stronger basal texture than the CR alloy. The average corrosion rate of the HSRR ZK60 sheet after 90-day immersion in Hank's solution is 0.17 mg cm-2 d-1, about 19% lower than that of the CR sheet. Its corrosion current density is 30.9 μA/cm2, about 45% lower than that of the CR sheet. Bio-corrosion resistance enhancement by HSRR can be mainly ascribe to the reduced grain size, the relatively adequate DRX, non-twinning, the coarser residual second-phase particles, the finer and denser nanometer precipitates and the slightly stronger (0001) texture.

  19. Preparation and characterization of aqueous dispersions of high amylose starch and conjugated linoleic acid complex.

    Science.gov (United States)

    Seo, Tae-Rang; Kim, Hee-Young; Lim, Seung-Taik

    2016-11-15

    Crystalline starch-CLA complexes were prepared by blending an alcoholic solution of conjugated linoleic acid (CLA) in an aqueous high-amylose maize starch dispersion. Recovery yield of CLA in the precipitates obtained by centrifuging the dispersion was dependent on reaction conditions such as temperature, time and pH. The CLA recovery reached a maximum when the reaction was performed at 90°C for 6h at neutral pH, with 67.7% of the initial CLA being co-precipitated with starch. The precipitates contained amylose-CLA complex exhibiting a V6I-type crystalline structure under X-ray diffraction analysis and a type II polymorph under DSC analysis. Ultrasonic treatment for the re-dispersed starch-CLA complex in water resulted in the reduction of hydrodynamic diameter of the complex particles to 201.5nm. The dispersion exhibited a zeta potential of -27.0mV and remained stable in an ambient storage without forming precipitates for more than 4weeks. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Preparation of cellulose nanocrystals from Humulus japonicus stem and the influence of high temperature pretreatment.

    Science.gov (United States)

    Jiang, Yani; Zhou, Jiping; Zhang, Qi; Zhao, Guoqi; Heng, Lin; Chen, Dongdong; Liu, Dongfang

    2017-05-15

    As one of the most abundant wild herbs in nature, the Humulus japonicus stem (HJS) is a new low-cost source of cellulosic material. In this work, cellulose nanocrystals (CNCs) were isolated from HJS using acid hydrolysis. The influence of high temperature pretreatment (HT pretreatment) on the properties and yields of these HT-HJS (HJS fibers after HT pretreatment at different temperatures) and HT-CNCs (CNCs prepared from the HT-HJS) was studied. The results showed that there was no variation of the chemical structure among the HT-HJS and HT-CNCs. The thermal stabilities and crystallinities of the HT-HJS were higher than bleached HJS. The average diameters of the HT-CNCs were significantly smaller while the average aspect ratios of them were obviously bigger than the CNCs, and the biggest average aspect ratio of HT140-CNCs (63.40) was almost twice of CNCs (32.00). Compared with the CNCs (70.05%, 212.8°C), the crystallinity and initial degradation temperature also showed increase for the HT-CNCs and increased up to maximum of 86.93% and 227.5°C for the HT160-CNCs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Preparation of monodisperse aqueous microspheres containing high concentration of l-ascorbic acid by microchannel emulsification.

    Science.gov (United States)

    Khalid, Nauman; Kobayashi, Isao; Neves, Marcos A; Uemura, Kunihiko; Nakajima, Mitsutoshi; Nabetani, Hiroshi

    2015-01-01

    Monodisperse aqueous microspheres containing high concentrations of l-ascorbic acid with different concentrations of sodium alginate (Na-ALG) and magnesium sulfate (MgSO4) were prepared by using microchannel emulsification (MCE). The continuous phase was water-saturated decane containing a 5% (w/w) hydrophobic emulsifier. The flow rate of the continuous phase was maintained at 10 mL h(-1), whereas the pressure applied to the disperse phase was varied between 3 and 25 kPa. The disperse phase optimized for successfully generating aqueous microspheres included 2% (w/w) Na-ALG and 1% (w/w) MgSO4. At a higher MgSO4 concentration, the generated microspheres resulted in coalescence and subsequent bursting. At a lower MgSO4 concentration, unstable and polydisperse microspheres were obtained. The aqueous microspheres generated from the MCs under optimized conditions had a mean particle diameter (dav) of 14-16 µm and a coefficient of variation (CV) of less than 8% at the disperse phase pressures of 5-15 kPa.

  2. One-pot preparation of a novel monolith for high performance liquid chromatography applications.

    Science.gov (United States)

    Jiao, Xiaoyan; Shen, Shigang; Shi, Tiesheng

    2015-12-15

    Various novel porous organic-based monoliths with the mode of hydrophobicity were synthesized by in situ free-radical crosslinking copolymerization and optimized for the separations of small molecules and high-performance reversed-phase chromatography (RP-chromatography). These monoliths contained co-polymers based on glycidyl methacrylate (GMA)/ethylene glycol dimethacrylate (EDMA)/tripropylene glycol diacrylate (TPGDA) or EDMA/TPGDA. A mixture of cetanol, methanol and poly (ethylene glycol) (PEG) was used as the porogen, with the ratio of these solvents being varied along with the polymerization temperature to generate a library of monoliths. The conditions were optimized and the resulting poly (GMA-co-TPGDA-co-EDMA) monolith was investigated by infrared spectrometer (IR), field emission scanning electron microscope (FESEM), and mercury intrusion porosimetry (MIP), respectively. The column performance was assessed by the separation of a series of neutral solutes of benzene derivatives. The result demonstrated that the prepared monolith exhibited an RP-chromatographic behavior and relatively homogeneous structure, good permeability and separation performance. Moreover, the relative standard deviations (RSDs) of the retention factor values for benzene derivatives were less than 1.5% (n=7, column-to-column). The approach used in this study was extended to the separation of anilines.

  3. Preparation and Characterization of a New Quercetin-bonded Stationary Phase for High Performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    李来生; 方奕珊; 陈红; 张杨

    2012-01-01

    A quercetin-bonded silica gel stationary phase (QUSP) containing natural flavonoid ligand was first prepared via γ-glycidoxypropyltrimethoxysilane (KH-560) as a coupling reagent for high-performance liquid chromatography. Its chemical structure was characterized by Fourier infrared spectroscopy, elemental analysis, thermal thermogravimetry and 13C cross polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR). The chromatographic property of QUSP was systematically evaluated by using neutral, basic and acidic aromatic com- pounds as probes. In order to clarify its retention mechanism, a comparative study of QUSP with conventional oc- tadecylsilyl-bonded stationary phase (ODS) was also carried out under the same conditions. The results showed that the new quercetin-bonded phase exhibited an excellent reversed-phase chromatographic property with relatively weak hydrophobicity. However, it has an advantage over ODS in the fast separation of polar aromatic compounds because the quercetin ligand could provide various sites besides hydrophobicity, such as hydrogen bonding, dipole-dipole, n-n staking and charge transfer interactions. QUSP was performed in the baseline separations of ion- ized polar basic or acidic compounds, including pyridines, anilines, pyrimidines, purines and phenols with symmet- ric peak shape in common mobile phases without buffer salt within relatively short time. The natural ligands from herbs are readily available and contain a variety of active sites, which facilitate the exploration of industrial chromatographic separation materials for green products.

  4. Preparation of graphene oxide-silver nanoparticle nanohybrids with highly antibacterial capability.

    Science.gov (United States)

    Zhu, Zhijun; Su, Min; Ma, Lan; Ma, Lina; Liu, Dianjun; Wang, Zhenxin

    2013-12-15

    A simple method based on electrostatic interactions was utilized to assemble silver nanoparticles (AgNPs) to graphene oxide (GO) sheets. This method allows conjugation of AgNPs with desired morphologies (densities, sizes and shapes) onto GO. In this process, poly(diallyldimethylammonium chloride) (PDDA) was introduced as an adhesive agent. The as-prepared graphene oxide-AgNPs composites (GO-AgNPs) have enhanced colloid stability and photo-stability than that of AgNPs. After conjugating to GO sheets, the antibacterial activities of AgNPs against Gram negative (G-) bacterial strain (Escherichia coli, E. coli) and Gram positive (G+) bacterial strain (Bacillus subtilis, B. subtilis) have been improved significantly. The antibacterial activity of GO-AgNPs is dependent on the size of AgNPs, i.e. the small AgNPs modified GO sheets show more effective antibacterial capability than that of large AgNPs modified GO sheets. Compared with AgNPs, the enhanced antibacterial activity of GO-AgNPs might not only be due to high stability of AgNPs anchored on GO sheets, but also the positive charged surface of hybrids which increases the electrostatic interaction of bacterial cell membrane with nanohybrids.

  5. Preparation of self-crosslinked acrylate emulsion with high elasticity and its rheological properties

    Institute of Scientific and Technical Information of China (English)

    CHEN Li-jun; WU Feng-qin; LI Dong-shuang; YANG Jian; LI Rong-xian

    2008-01-01

    Using butyl acrylate (BA), methyl methacrylate (MMA), methacrylic acid (MAA) and mixed emulsifier as raw materials, the self-crosslinked emulsion was prepared via pre-emulsified and semi-continuous seeded emulsion polymerization technology in the presence of N-hydroxymethyl acrylamide and poly solidum maleate. The influence of mass ratio of BA to MMA, amount of N-hydroxymethyl acrylamide and poly solidum maleate on the rheological properties of the self-crosslinked emulsion was studied. Possible cross-linked mechanism of self-crosslinked monomer was investigated. And the relationship between emulsion viscosity and shear rate was investigated. The results show that the self-crosslinked acrylate emulsion with high elasticity can be synthesized when the mass fractions of BA is 60%, MMA is 40%, and added amount of N-hydroxymethyl acrylamide is 2.5%-3.0% and added amount of poly solidum maleate is 0.3%-0.4%. The self-crosslinkage process of N-hydroxymethyl acrylamide involves two steps. One is copolymer zation of N-hydroxymethyl acrylamide and acrylate, the other is cross-linkage among polymer molecules via condensation reaction of methylol. The emulsion is of rheological properties of pseudo-plastic fluid and belongs to non-Newtonian fluid.

  6. High T(sub c) thin film superconductors: Preparation, patterning and characterization