Microwave tomography enhanced GPR surveys in Centaur’s Domus, Regio VI of Pompeii, Italy

International Nuclear Information System (INIS)

Catapano, I; Crocco, L; Napoli, R Di; Soldovieri, F; Brancaccio, A; Pesando, F; Aiello, A

2012-01-01

The archaeological area of Pompeii (Naples, Italy) is known worldwide as one of the most remarkable examples of a Roman Empire town, but its origins are prior to the Roman age and there is a huge archeological interest in discovering the history of the forma urbis. With respect to this framework, the paper presents results from microwave tomography enhanced ground penetrating radar (GPR) surveys carried out in the Centaur’s Domus, Regio VI, one of the most ancient housing areas of Pompeii. The GPR prospections aimed at addressing and driving the archeological excavation campaign performed in this area in October 2010. The results of stratigraphic assays are used to assess the reliability of the tomographic images obtained. (paper)

STAR FORMATION FEEDBACK AND METAL-ENRICHMENT HISTORY OF THE INTERGALACTIC MEDIUM

International Nuclear Information System (INIS)

Cen Renyue; Chisari, Nora Elisa

2011-01-01

Using the state-of-the-art cosmological hydrodynamic simulations of the standard cold dark matter model with star formation feedback strength normalized to match the observed star formation history of the universe at z= 0-6, we compute the metal-enrichment history of the intergalactic medium (IGM). Overall we show that galactic superwind (GSW) feedback from star formation can transport metals to the IGM and that the properties of simulated metal absorbers match current observations. The distance of influence of GSW from galaxies is typically limited to about ≤0.5 Mpc and within regions of overdensity δ ≥ 10. Most C IV and O VI absorbers are located within shocked regions of elevated temperature (T ≥ 2 x 10 4 K), overdensity (δ ≥ 10), and metallicity ([Z/Z sun ] = [ - 2.5, - 0.5]), enclosed by double shocks propagating outward. O VI absorbers have typically higher metallicity, lower density, and higher temperature than C IV absorbers. For O VI absorbers, collisional ionization dominates over the entire redshift range z= 0-6, whereas for C IV absorbers the transition occurs at moderate redshift z ∼ 3 from collisionally dominated to photoionization dominated. We find that the observed column density distributions for C IV and O VI in the range log N cm 2 =12-15 are reasonably reproduced by the simulations. The evolution of mass densities contained in C IV and O VI lines, Ω CIV and Ω OVI , is also in good agreement with observations, which shows a near constancy at low redshifts and an exponential drop beyond redshift z= 3-4. For both C IV and O VI, most absorbers are transient and the amount of metals probed by C IV and O VI lines of column log N cm 2 =12-15 is only ∼2% of total metal density at any epoch. While gravitational shocks from large-scale structure formation dominate the energy budget (80%-90%) for turning about 50% of the IGM to the warm-hot intergalactic medium (WHIM) by z = 0, GSW feedback shocks are energetically dominant over

Survey on multisensory feedback virtual reality dental training systems.

Science.gov (United States)

Wang, D; Li, T; Zhang, Y; Hou, J

2016-11-01

Compared with traditional dental training methods, virtual reality training systems integrated with multisensory feedback possess potentials advantages. However, there exist many technical challenges in developing a satisfactory simulator. In this manuscript, we systematically survey several current dental training systems to identify the gaps between the capabilities of these systems and the clinical training requirements. After briefly summarising the components, functions and unique features of each system, we discuss the technical challenges behind these systems including the software, hardware and user evaluation methods. Finally, the clinical requirements of an ideal dental training system are proposed. Future research/development areas are identified based on an analysis of the gaps between current systems and clinical training requirements. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A Pharmaceutical Bioethics Consultation Service: Six-Year Descriptive Characteristics and Results of a Feedback Survey.

Science.gov (United States)

Van Campen, Luann E; Allen, Albert J; Watson, Susan B; Therasse, Donald G

2015-04-03

Background : Bioethics consultations are conducted in varied settings, including hospitals, universities, and other research institutions, but there is sparse information about bioethics consultations conducted in corporate settings such as pharmaceutical companies. The purpose of this article is to describe a bioethics consultation service at a pharmaceutical company, to report characteristics of consultations completed by the service over a 6-year period, and to share results of a consultation feedback survey. Methods : Data on the descriptive characteristics of bioethics consultations were collected from 2008 to 2013 and analyzed in Excel 2007. Categorical data were analyzed via the pivot table function, and time-based variables were analyzed via formulas. The feedback survey was administered to consultation requesters from 2009 to 2012 and also analyzed in Excel 2007. Results : Over the 6-year period, 189 bioethics consultations were conducted. The number of consultations increased from five per year in 2008 to approximately one per week in 2013. During this time, the format of the consultation service was changed from a committee-only approach to a tiered approach (tailored to the needs of the case). The five most frequent topics were informed consent, early termination of a clinical trial, benefits and risks, human biological samples, and patient rights. The feedback survey results suggest the consultation service is well regarded overall and viewed as approachable, helpful, and responsive. Conclusions : Pharmaceutical bioethics consultation is a unique category of bioethics consultation that primarily focuses on pharmaceutical research and development but also touches on aspects of clinical ethics, business ethics, and organizational ethics. Results indicate there is a demand for a tiered bioethics consultation service within this pharmaceutical company and that advice was valued. This company's experience indicates that a bioethics consultation service

"Are You Listening Please?" The Advantages of Electronic Audio Feedback Compared to Written Feedback

Science.gov (United States)

Lunt, Tom; Curran, John

2010-01-01

Feedback on students' work is, probably, one of the most important aspects of learning, yet students' report, according to the National Union of Students (NUS) Survey of 2008, unhappiness with the feedback process. Students were unhappy with the quality, detail and timing of feedback. This paper examines the benefits of using audio, as opposed to…

Feedback to Managers, Volume II: A Review and Comparison of Sixteen Multi-Rater Feedback Instruments.

Science.gov (United States)

Van Velsor, Ellen; Leslie, Jean Brittain

"Feedback to Managers" is a two-volume report. Volume 2 compares 16 of the better feedback instruments available. The following are the instruments: (1) ACUMEN Group Feedback; (2) BENCHMARKS; (3) the Campbell Leadership Index; (4) COMPASS: the Managerial Practices Survey; (5) the Executive Success Profile; (6) Leader Behavior Analysis…

A Survey of Metal Lines at High Redshift. II. SDSS Absorption Line Studies—O VI Line Density, Space Density, and Gas Metallicity at z abs ~ 3.0

Science.gov (United States)

Frank, S.; Mathur, S.; Pieri, M.; York, D. G.

2010-09-01

We have analyzed a large data set of O VI absorber candidates found in the spectra of 3702 Sloan Digital Sky Survey (SDSS) quasars, focusing on a subsample of 387 active galactic nuclei sight lines with an average S/N >=5.0, allowing for the detection of absorbers above a rest-frame equivalent width limit of W r >= 0.19 Å for the O VI 1032 Å component. Accounting for random interlopers mimicking an O VI doublet, we derive for the first time a secure lower limit for the redshift number density ΔN/Δz for redshifts z abs >= 2.8. With extensive Monte Carlo simulations, we quantify the losses of absorbers due to blending with the ubiquitous Lyα forest lines and estimate the success rate of retrieving each individual candidate as a function of its redshift, the emission redshift of the quasar, the strength of the absorber, and the measured signal-to-noise ratio (S/N) of the spectrum by modeling typical Lyman forest spectra. These correction factors allow us to derive the "incompleteness and S/N-corrected" redshift number densities of O VI absorbers: ΔN O VI,c /Δzc (2.8 secure lower limit for the contribution of O VI to the closure mass density at the redshifts probed here: ΩO VI (2.8 = 1.9 × 10-8 h -1. We show that the strong lines we probe account for over 65% of the mass in the O VI absorbers; the weak absorbers, while dominant in line number density, do not contribute significantly to the mass density. Making a conservative assumption about the ionization fraction, {O VI}/{O}, and adopting the Anders & Grevesse solar abundance values, we derive the mean metallicity of the gas probed in our search: ζ(2.8 = 3.6 × 10-4 h, in good agreement with other studies. These results demonstrate that large spectroscopic data sets such as SDSS can play an important role in QSO absorption line studies, in spite of the relatively low resolution.

Customer Feedback: A Framework for Action.

Science.gov (United States)

Micceri, Ted; Takalkar, Pradnya; Waugh, Gordon

This paper is designed to identify effective methods and to lay out steps that can be used in a customer feedback survey process. In order for the results of any customer survey to stimulate useful changes in an organization, it is essential that the support of key players be present from the beginning. Developing a customer feedback process is a…

An electrochemical study of U(VI) and Cr(VI) in molten borates

International Nuclear Information System (INIS)

Brigaudeau, M.; Gregori de Pinochet, I. de

1977-01-01

The electrochemical reduction of U(VI) and Cr(VI), in molten Na 2 B 4 O 7 at 800 deg C was studied by means of linear sweep voltammetry, and chronopotentiometry. The reduction of U(VI) to U(V) proceeded reversibly at a platinum electrode. The diffusion coefficient for the U(VI) species at 800 deg C was 4.10 -7 cm 2 .s -1 . The activation energy of diffusion was (34,8 +- 0,8) kcal. mole -1 . Electrochemical studies of Cr(VI) at 800 0 C reveal a two-step reduction process at a platinum electrode. Only the voltammogram for the first step charge transfer process was studied. Analysis indicated that Cr(VI) is reversibly reduced to Cr(III) at a platinum electrode. The diffusion coefficient for Cr(VI) at 800 0 C is 1,9.10 -7 cm 2 .s -1 [fr

Perceiving haptic feedback in virtual reality simulators.

Science.gov (United States)

Våpenstad, Cecilie; Hofstad, Erlend Fagertun; Langø, Thomas; Mårvik, Ronald; Chmarra, Magdalena Karolina

2013-07-01

To improve patient safety, training of psychomotor laparoscopic skills is often done on virtual reality (VR) simulators outside the operating room. Haptic sensations have been found to influence psychomotor performance in laparoscopy. The emulation of haptic feedback is thus an important aspect of VR simulation. Some VR simulators try to simulate these sensations with handles equipped with haptic feedback. We conducted a survey on how laparoscopic surgeons perceive handles with and without haptic feedback. Surgeons with different levels of experience in laparoscopy were asked to test two handles: Xitact IHP with haptic feedback and Xitact ITP without haptic feedback (Mentice AB, Gothenburg, Sweden), connected to the LapSim (Surgical Science AB, Sweden) VR simulator. They performed two tasks on the simulator before answering 12 questions regarding the two handles. The surgeons were not informed about the differences in the handles. A total of 85 % of the 20 surgeons who participated in the survey claimed that it is important that handles with haptic feedback feel realistic. Ninety percent of the surgeons preferred the handles without haptic feedback. The friction in the handles with haptic feedback was perceived to be as in reality (5 %) or too high (95 %). Regarding the handles without haptic feedback, the friction was perceived as in reality (45 %), too low (50 %), or too high (5 %). A total of 85 % of the surgeons thought that the handle with haptic feedback attempts to simulate the resistance offered by tissue to deformation. Ten percent thought that the handle succeeds in doing so. The surveyed surgeons believe that haptic feedback is an important feature on VR simulators; however, they preferred the handles without haptic feedback because they perceived the handles with haptic feedback to add additional friction, making them unrealistic and not mechanically transparent.

Chromium(VI) release from leather and metals can be detected with a diphenylcarbazide spot test.

Science.gov (United States)

Bregnbak, David; Johansen, Jeanne D; Jellesen, Morten S; Zachariae, Claus; Thyssen, Jacob P

2015-11-01

Along with chromium, nickel and cobalt are the clinically most important metal allergens. However, unlike for nickel and cobalt, there is no validated colorimetric spot test that detects chromium. Such a test could help both clinicians and their patients with chromium dermatitis to identify culprit exposures. To evaluate the use of diphenylcarbazide (DPC) as a spot test reagent for the identification of chromium(VI) release. A colorimetric chromium(VI) spot test based on DPC was prepared and used on different items from small market surveys. The DPC spot test was able to identify chromium(VI) release at 0.5 ppm without interference from other pure metals, alloys, or leather. A market survey using the test showed no chromium(VI) release from work tools (0/100). However, chromium(VI) release from metal screws (7/60), one earring (1/50), leather shoes (4/100) and leather gloves (6/11) was observed. We found no false-positive test reactions. Confirmatory testing was performed with X-ray fluorescence (XRF) and spectrophotometrically on extraction fluids. The use of DPC as a colorimetric spot test reagent appears to be a good and valid test method for detecting the release of chromium(VI) ions from leather and metal articles. The spot test has the potential to become a valuable screening tool. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Patterns in the form of formative feedback and student response

DEFF Research Database (Denmark)

Ellegaard, Marianne; Damsgaard, Linn; Bruun, Jesper

2018-01-01

Formativ feedback modtager i øjeblikket opmærksomhed som et effektivt middel til at øge studerendes læring. Men hvordan man sætter rammerne for at opnå den bedste effekt er løbende til debat. I denne undersøgelse analyserer vi et skriftligt datasæt med 174 segmenter af lærerfeedback og studerende...

Brazil Geological Basic Survey Program - Lima Duarte - Sheet SF.23-X-C-VI - Minas Gerais State

International Nuclear Information System (INIS)

Pinto, C.P.

1991-01-01

The present report refers to the Lima Duarte sheet (SF.23-X-C-VI) systematic geological mapping, on the 1:100.000 scale. The surveyed area, localized in the Zona da Mata, Juiz de Fora micro-region, in South Minas Gerais, is dominantly composed by metamorphic rocks of the granulite and amphibolite facies and presents important diphtheritic process. An analysis of the Crustal Evolution Patterns based mostly on geological mapping, and gravimetric, air magneto metric and geochronologic data is given in the Chapter 6, Part II, of the text. Geophysical information is in the Chapter 5, Part II. Seventy two samples were analysed for oxides, trace-elements and REE, to provide litho environment and metallogenesis definition subsidies. Were studied 174 petrographic thin section, and 48 samples of quartzite and schist residual materials were analysed for heavy metals. Seven hundred and fifty outcrops were described. A geochemical survey, based on 81 pan concentrated samples and 277 stream sediments was carried out throughout the Sheet. The anomalies found in the stream sediments reflect the geochemical signature of the analysed elements for the litho types of the investigated terrains. (author)

Perceived Insider Status and Feedback Reactions: A Dual Path of Feedback Motivation Attribution

Directory of Open Access Journals (Sweden)

Weijiong Wu

2017-05-01

Full Text Available Many studies have evaluated how the characteristics of feedback receiver, feedback deliverer and feedback information influence psychological feedback reactions of the feedback receiver while largely neglecting that feedback intervention is a kind of social interaction process. To address this issue, this study proposes that employees’ perceived insider status (PIS, as a kind of employee-organization relationship, could also influence employees’ reactions to supervisory feedback. In particular, this study investigates the influence of PIS focusing on affective and cognitive feedback reactions, namely feedback satisfaction and feedback utility. Surveys were conducted in a machinery manufacturing company in the Guangdong province of China. Samples were collected from 192 employees. Data analysis demonstrated that PIS and feedback utility possessed a U-shaped relationship, whereas PIS and feedback satisfaction exhibited positively linear relationships. The analysis identified two kinds of mediating mechanisms related to feedback satisfaction and feedback utility. Internal feedback motivation attribution partially mediated the relationship between PIS and feedback satisfaction but failed to do the same with respect to the relationship between PIS and feedback utility. In contrast, external feedback motivation attribution partially mediated the relationship between PIS and feedback utility while failing to mediate the relationship between PIS and feedback satisfaction. Theoretical contributions and practical implications of the findings are discussed at the end of the paper.

Useful but Different: Resident Physician Perceptions of Interprofessional Feedback.

Science.gov (United States)

Vesel, Travis P; O'Brien, Bridget C; Henry, Duncan M; van Schaik, Sandrijn M

2016-01-01

Phenomenon: Based on recently formulated interprofessional core competencies, physicians are expected to incorporate feedback from other healthcare professionals. Based on social identity theory, physicians likely differentiate between feedback from members of their own profession and others. The current study examined residents' experiences with, and perceptions of, interprofessional feedback. In 2013, Anesthesia, Obstetrics-Gynecology, Pediatrics, and Psychiatry residents completed a survey including questions about frequency of feedback from different professionals and its perceived value (5-point scale). The authors performed an analysis of variance to examine interactions between residency program and profession of feedback provider. They conducted follow-up interviews with a subset of residents to explore reasons for residents' survey ratings. Fifty-two percent (131/254) of residents completed the survey, and 15 participated in interviews. Eighty percent of residents reported receiving written feedback from physicians, 26% from nurses, and less than 10% from other professions. There was a significant interaction between residency program and feedback provider profession, F(21, 847) = 3.82, p feedback provider profession, F(7, 847) = 73.7, p feedback from attending physicians higher than feedback from others, and anesthesia residents rated feedback from other professionals significantly lower than other residents. Ten major themes arose from qualitative data analysis, which revealed an overall positive attitude toward interprofessional feedback and clarified reasons behind residents' perceptions and identified barriers. Insights: Residents in our study reported limited exposure to interprofessional feedback and valued such feedback less than intraprofessional feedback. However, our data suggest opportunities exist for effective utilization of interprofessional feedback.

Vi, de civiliserede

DEFF Research Database (Denmark)

Nyemann, Dorthe

2016-01-01

Vi har i årtier troet på, at mennesker under de rette omstændigheder kan lykkes med at leve i fred og fordragelighed med hinanden. Skal vi til at erkende, at også vores samfundsstrukturer kun er en tynd fernis ovenpå et utæmmeligt voldspotentiale og egoisme?......Vi har i årtier troet på, at mennesker under de rette omstændigheder kan lykkes med at leve i fred og fordragelighed med hinanden. Skal vi til at erkende, at også vores samfundsstrukturer kun er en tynd fernis ovenpå et utæmmeligt voldspotentiale og egoisme?...

Physician performance feedback in a Canadian academic center.

Science.gov (United States)

Garvin, Dennis; Worthington, James; McGuire, Shaun; Burgetz, Stephanie; Forster, Alan J; Patey, Andrea; Gerin-Lajoie, Caroline; Turnbull, Jeffrey; Roth, Virginia

2017-10-02

Purpose This paper aims at the implementation and early evaluation of a comprehensive, formative annual physician performance feedback process in a large academic health-care organization. Design/methodology/approach A mixed methods approach was used to introduce a formative feedback process to provide physicians with comprehensive feedback on performance and to support professional development. This initiative responded to organization-wide engagement surveys through which physicians identified effective performance feedback as a priority. In 2013, physicians primarily affiliated with the organization participated in a performance feedback process, and physician satisfaction and participant perceptions were explored through participant survey responses and physician leader focus groups. Training was required for physician leaders prior to conducting performance feedback discussions. Findings This process was completed by 98 per cent of eligible physicians, and 30 per cent completed an evaluation survey. While physicians endorsed the concept of a formative feedback process, process improvement opportunities were identified. Qualitative analysis revealed the following process improvement themes: simplify the tool, ensure leaders follow process, eliminate redundancies in data collection (through academic or licensing requirements) and provide objective quality metrics. Following physician leader training on performance feedback, 98 per cent of leaders who completed an evaluation questionnaire agreed or strongly agreed that the performance feedback process was useful and that training objectives were met. Originality/value This paper introduces a physician performance feedback model, leadership training approach and first-year implementation outcomes. The results of this study will be useful to health administrators and physician leaders interested in implementing physician performance feedback or improving physician engagement.

Plutonium(VI) accumulation and reduction by lichen biomass: correlation with U(VI)

International Nuclear Information System (INIS)

Ohnuki, Toshihiko; Aoyagi, Hisao; Kitatsuji, Yoshihiro; Samadfam, Mohammad; Kimura, Yasuhiko; William Purvis, O.

2004-01-01

The uptake of plutonium(VI) and uranium(VI) by lichen biomass was studied in the foliose lichen Parmotrema tinctorum to elucidate the migration behavior of Pu and U in the terrestrial environment. Pu and U uptake by P. tinctorum averaged 0.040±0.010 and 0.055±0.015 g g dry -1 , respectively, after 96 h incubation with 4.0x10 -4 mol l -1 Pu solutions of pH 3, 4 and 5. SEM observations showed that the accumulated Pu is evenly distributed on the upper and lower surfaces of P. tinctorum, in contrast to U(VI), which accumulated in both cortical and medullary layers. UV/VIS absorption spectroscopy demonstrates that a fraction of Pu(VI) in the solution is reduced to Pu(V) by the organic substances released from P. tinctorum, and the accumulated Pu on the surface is reduced to Pu(IV), while U(VI) keeps the oxidation state of VI. Since the solubility of Pu(IV) hydroxides is very low, reduced Pu(VI) does not penetrate to the medullary layers, but is probably precipitated as Pu(IV) hydroxides on the cortical lichen surface. It is concluded that the uptake and reduction of Pu(VI) by lichens is important to determine the mobilization and oxidation states of Pu in the terrestrial environment

Anaerobic bio-removal of uranium (VI) and chromium (VI): Comparison of microbial community structure

International Nuclear Information System (INIS)

Martins, Monica; Faleiro, Maria Leonor; Chaves, Sandra; Tenreiro, Rogerio; Santos, Erika; Costa, Maria Clara

2010-01-01

Several microbial communities, obtained from uranium contaminated and non-contaminated samples, were investigated for their ability to remove uranium (VI) and the cultures capable for this removal were further assessed on their efficiency for chromium (VI) removal. The highest efficiency for removal of both metals was observed on a consortium from a non-contaminated soil collected in Monchique thermal place, which was capable to remove 91% of 22 mg L -1 U(VI) and 99% of 13 mg L -1 Cr(VI). This study revealed that uranium (VI) removing communities have also ability to remove chromium (VI), but when uranium (VI) was replaced by chromium (VI) several differences in the structure of all bacterial communities were observed. TGGE and phylogenetic analysis of 16S rRNA gene showed that the uranium (VI) removing bacterial consortia are mainly composed by members of Rhodocyclaceae family and Clostridium genus. On the other hand, bacteria from Enterobacteriaceae family were detected in the community with ability for chromium (VI) removal. The existence of members of Enterobacteriaceae and Rhodocyclaceae families never reported as chromium or uranium removing bacteria, respectively, is also a relevant finding, encouraging the exploitation of microorganisms with new abilities that can be useful for bioremediation.

Anaerobic bio-removal of uranium (VI) and chromium (VI): Comparison of microbial community structure

Energy Technology Data Exchange (ETDEWEB)

Martins, Monica [Centro de Ciencias do Mar, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Faleiro, Maria Leonor [IBB - Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Chaves, Sandra; Tenreiro, Rogerio [Universidade de Lisboa, Faculdade de Ciencias, Centro de Biodiversidade, Genomica Integrativa e Funcional (BioFIG), Campus de FCUL, Campo Grande 1749-016 Lisboa (Portugal); Santos, Erika [Centro de Ciencias do Mar, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Costa, Maria Clara, E-mail: mcorada@ualg.pt [Centro de Ciencias do Mar, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal)

2010-04-15

Several microbial communities, obtained from uranium contaminated and non-contaminated samples, were investigated for their ability to remove uranium (VI) and the cultures capable for this removal were further assessed on their efficiency for chromium (VI) removal. The highest efficiency for removal of both metals was observed on a consortium from a non-contaminated soil collected in Monchique thermal place, which was capable to remove 91% of 22 mg L{sup -1} U(VI) and 99% of 13 mg L{sup -1} Cr(VI). This study revealed that uranium (VI) removing communities have also ability to remove chromium (VI), but when uranium (VI) was replaced by chromium (VI) several differences in the structure of all bacterial communities were observed. TGGE and phylogenetic analysis of 16S rRNA gene showed that the uranium (VI) removing bacterial consortia are mainly composed by members of Rhodocyclaceae family and Clostridium genus. On the other hand, bacteria from Enterobacteriaceae family were detected in the community with ability for chromium (VI) removal. The existence of members of Enterobacteriaceae and Rhodocyclaceae families never reported as chromium or uranium removing bacteria, respectively, is also a relevant finding, encouraging the exploitation of microorganisms with new abilities that can be useful for bioremediation.

The new WMO RA VI Regional Climate Centre on Climate Monitoring

Science.gov (United States)

Rapp, J.; Nitsche, H.

2010-09-01

Regional Climate Centres (RCCs) are institutions with the capacity and mandate by WMO to develop high quality regional-scale products using global products and incorporating regional information. Recently a pilot network of three RCC consortia was established for the WMO region RA VI (Europe and Middle East): • RCC node on climate data, • RCC node on climate monitoring, • RCC node on long-range forecasting. DWD/Germany has taken the responsibility of the RCC node on climate monitoring (RRC-CM). Further consortium members are Armstatehydromet/Armenia, Météo-France/France, KNMI/The Netherlands, RHMS/Serbia, and TSMS/Turkey. RCCs provide online access to their products and services to national meteorological and hydrological services and to other regional users. Vice versa, RCCs receive data, products, know-how and feedbacks from the meteorological services as a main source for regional information. By the same time, they provide regional data, products and feedbacks to Global Production Centres and Lead Centres for respective verification and product optimisation of the global-scale information. The RCC-CM will perform basic functions covering the domain of climate monitoring: • Annual and monthly climate diagnostic bulletins, • Monthly monitoring maps: global, RAVI, Eastern Mediterranean, South Caucasus, • Reference climatologies and trend maps, • RA VI climate monitoring WebPortal, • Climate watches, • Training; Research and Development (R&D). The poster shows the current stage of development of the RCC-CM by means of example products.

Enhanced control and sensing for the REMOTEC ANDROS Mk VI robot. CRADA final report

International Nuclear Information System (INIS)

Spelt, P.F.; Harvey, H.W.

1998-01-01

This Cooperative Research and Development Agreement (CRADA) between Lockheed Martin Energy Systems, Inc., and REMOTEC, Inc., explored methods of providing operator feedback for various work actions of the ANDROS Mk VI teleoperated robot. In a hazardous environment, an extremely heavy workload seriously degrades the productivity of teleoperated robot operators. This CRADA involved the addition of computer power to the robot along with a variety of sensors and encoders to provide information about the robot's performance in and relationship to its environment. Software was developed to integrate the sensor and encoder information and provide control input to the robot. ANDROS Mk VI robots are presently used by numerous electric utilities to perform tasks in reactors where substantial exposure to radiation exists, as well as in a variety of other hazardous environments. Further, this platform has potential for use in a number of environmental restoration tasks, such as site survey and detection of hazardous waste materials. The addition of sensors and encoders serves to make the robot easier to manage and permits tasks to be done more safely and inexpensively (due to time saved in the completion of complex remote tasks). Prior research on the automation of mobile platforms with manipulators at Oak Ridge National Laboratory's Center for Engineering Systems Advanced Research (CESAR, B ampersand R code KC0401030) Laboratory, a BES-supported facility, indicated that this type of enhancement is effective. This CRADA provided such enhancements to a successful working teleoperated robot for the first time. Performance of this CRADA used the CESAR laboratory facilities and expertise developed under BES funding

II-VI semiconductor compounds

CERN Document Server

1993-01-01

For condensed matter physicists and electronic engineers, this volume deals with aspects of II-VI semiconductor compounds. Areas covered include devices and applications of II-VI compounds; Co-based II-IV semi-magnetic semiconductors; and electronic structure of strained II-VI superlattices.

Leadership development in a professional medical society using 360-degree survey feedback to assess emotional intelligence.

Science.gov (United States)

Gregory, Paul J; Robbins, Benjamin; Schwaitzberg, Steven D; Harmon, Larry

2017-09-01

The current research evaluated the potential utility of a 360-degree survey feedback program for measuring leadership quality in potential committee leaders of a professional medical association (PMA). Emotional intelligence as measured by the extent to which self-other agreement existed in the 360-degree survey ratings was explored as a key predictor of leadership quality in the potential leaders. A non-experimental correlational survey design was implemented to assess the variation in leadership quality scores across the sample of potential leaders. A total of 63 of 86 (76%) of those invited to participate did so. All potential leaders received feedback from PMA Leadership, PMA Colleagues, and PMA Staff and were asked to complete self-ratings regarding their behavior. Analyses of variance revealed a consistent pattern of results as Under-Estimators and Accurate Estimators-Favorable were rated significantly higher than Over-Estimators in several leadership behaviors. Emotional intelligence as conceptualized in this study was positively related to overall performance ratings of potential leaders. The ever-increasing roles and potential responsibilities for PMAs suggest that these organizations should consider multisource performance reviews as these potential future PMA executives rise through their organizations to assume leadership positions with profound potential impact on healthcare. The current findings support the notion that potential leaders who demonstrated a humble pattern or an accurate pattern of self-rating scored significantly higher in their leadership, teamwork, and interpersonal/communication skills than those with an aggrandizing self-rating.

Cinética e equilíbrio de adsorção dos oxiânions Cr (VI, Mo (VI e Se (VI pelo sal de amônio quaternário de quitosana Kinetics and equilibrium of adsorption of oxyanions Cr (VI, Mo (VI and Se (VI by quaternary ammonium chitosan salt

Directory of Open Access Journals (Sweden)

Viviane A. Spinelli

2005-07-01

Full Text Available O sal quaternário de quitosana foi sintetizado com cloreto de glicidil trimetil amônio. A modificação química foi caracterizada por espectrometria no IV, RMN de 13C e ¹H, e mmol/g de grupos quaternários presentes na matriz polimérica por condutimetria. A remoção de Cr (VI, Mo (VI e Se (VI, em meio aquoso, foi investigada em processo de batelada. A adsorção mostrou ser dependente do pH para o Cr (VI e Se (VI, com um pH ótimo de adsorção, entre 4,0 a 6,0. Para o Mo (VI a adsorção manteve-se quase constante no intervalo de pH entre 4,0 e 11,5. O modelo de isoterma de Langmuir descreveu melhor os dados de equilíbrio na faixa de concentração investigada. No presente estudo, um grama do sal quaternário de quitosana reticulado com glutaraldeído adsorveu 68,3 mg de Cr, 63,4 mg de Mo e 90,0 mg de Se. A velocidade de adsorção, no processo, segue a equação cinética de pseudo segunda-ordem, sendo que o equilíbrio para os três íons foi alcançado próximo aos 200 minutos. A análise dispersiva de raios-X para o Cr (VI mostrou que o principal mecanismo de adsorção é a troca iônica entre os íons Cl- da superfície do polímero pelos oxiânions. O trocador aniônico apresentou a seguinte ordem de seletividade: Cr (VI > Mo (VI > Se (VI.Quaternary chitosan salt was synthesized in the presence of glycidyl trimetyl ammonium chloride. The polymer was characterized by spectroscopic techniques: infrared, 13C and ¹H NMR, while the amount of quaternary ammonium groups was obtained by condutimetry. The removal of Cr (VI, Mo (VI and Se (VI from aqueous solutions was carried out in batch adsorption processes. The process seemed to be pH dependent for Cr (VI and Se (VI with an optimum pH ranging from 4.0 to 6.0; while for Mo (VI the adsorption remained almost constant within the range between 4.0 and 11.5. The Langmuir isotherm model provided the best fit of the equilibrium data over the whole concentration investigated. In the experiment

U(VI) sorption on kaolinite. Effects of pH, U(VI) concentration and oxyanions

International Nuclear Information System (INIS)

Liang Gao; Ziqian Yang; Keliang Shi; Xuefeng Wang; Zhijun Guo; Wangsuo Wu

2010-01-01

U(VI) sorption on kaolinite was studied as functions of contact time, pH, U(VI) concentration, solid-to-liquid ratio (m/V) by using a batch experimental method. The effects of sulfate and phosphate on U(VI) sorption were also investigated. It was found that the sorption kinetics of U(VI) can be described by a pseudo-second-order model. Potentiometric titrations at variable ionic strengths indicated that the titration curves of kaolinite were not sensitive to ionic strength, and that the pH of the zero net proton charge (pH PZNPC ) was at 6.9. The sorption of U(VI) on kaolinite increased with pH up to 6.5 and reached a plateau at pH >6.5. The presence of phosphate strongly increased U(VI) sorption especially at pH <5.5, which may be due to formation of ternary surface complexes involving phosphate. In contrast, the presence of sulfate did not cause any apparent effect on U(VI) sorption. A double layer model was used to interpret both results of potentiometric titrations and U(VI) sorption on kaolinite. (author)

Galactic and Circumgalactic O VI and its Impact on the Cosmological Metal and Baryon Budgets at 2 < z <~ 3.5

Science.gov (United States)

Lehner, N.; O'Meara, J. M.; Fox, A. J.; Howk, J. C.; Prochaska, J. X.; Burns, V.; Armstrong, A. A.

2014-06-01

We present the first results from our NASA Keck Observatory Database of Ionized Absorbers toward Quasars (KODIAQ) survey which aims to characterize the properties of the highly ionized gas of galaxies and their circumgalactic medium (CGM) at 2 1, log N_{H\\,\\scriptsize{I}} \\textgreater 17.3) as probes of these galaxies and their CGM where both transitions of the O VI doublet have little contamination from the Lyα, β forests. We found 20 absorbers that satisfy these rules: 7 Lyman limit systems (LLSs), 8 super-LLSs (SLLSs) and 5 damped Lyα (DLAs). The O VI detection rate is 100% for the DLAs, 71% for the LLSs, and 63% for the SLLSs. When O VI is detected, log \\langle N_{O\\,\\scriptsize{VI}} \\rangle = 14.9 +/- 0.3, an average O VI column density substantially larger and with a smaller dispersion than found in blind O VI surveys at similar redshifts. Strong O VI absorption is therefore nearly ubiquitous in the CGM of z ~ 2-3 galaxies. The total velocity widths of the O VI profiles are also large (200 \\le \\Delta v_{O\\,\\scriptsize{VI}} \\le 400 km s-1). These properties are quite similar to those seen for O VI in low-z star-forming galaxies, and therefore we hypothesize that these strong CGM O VI absorbers (with τLL > 1) at 2 account, we determine that the τLL > 1 absorbers could contain as much as 3%-14% of the cosmic baryon budget at z ~ 2-3, only second to the Lyα forest. We conservatively show that 5%-20% of the metals ever produced at z ~ 2-3 are in form of highly ionized metals ejected in the CGM of galaxies. We dedicate this paper and the KODIAQ project to the memory and families of Wal Sargent and Arthur M. Wolfe. Without the vision and terrific efforts of these two scientists, this survey would not exist. Their careers have greatly inspired and influenced our own, and we hope that their work continues to flourish with this archival data set.

Chromium(VI) release from leather and metals can be detected with a diphenylcarbazide spot test

DEFF Research Database (Denmark)

Bregnbak, David; Johansen, Jeanne D.; Jellesen, Morten Stendahl

2015-01-01

Along with chromium, nickel and cobalt are the clinically most important metal allergens. However, unlike for nickel and cobalt, there is no validated colorimetric spot test that detects chromium. Such a test could help both clinicians and their patients with chromium dermatitis to identify culprit...... exposures. To evaluate the use of diphenylcarbazide (DPC) as a spot test reagent for the identification of chromium(VI) release. A colorimetric chromium(VI) spot test based on DPC was prepared and used on different items from small market surveys. The DPC spot test was able to identify chromium(VI) release...

Managers' Feedback Seeking Propensities on their Intra- Personal ...

African Journals Online (AJOL)

Based on the idea that feedback seeking enhances job performance, the study was aimed at investigating managers' feedback seeking tendencies on their intra personal, interpersonal and leadership skills, and their preferred feedback sources: subordinates, peers and superiors. Using cross-sectional survey design, 156 ...

KENO-VI Primer: A Primer for Criticality Calculations with SCALE/KENO-VI Using GeeWiz

International Nuclear Information System (INIS)

Bowman, Stephen M.

2008-01-01

The SCALE (Standardized Computer Analyses for Licensing Evaluation) computer software system developed at Oak Ridge National Laboratory is widely used and accepted around the world for criticality safety analyses. The well-known KENO-VI three-dimensional Monte Carlo criticality computer code is one of the primary criticality safety analysis tools in SCALE. The KENO-VI primer is designed to help a new user understand and use the SCALE/KENO-VI Monte Carlo code for nuclear criticality safety analyses. It assumes that the user has a college education in a technical field. There is no assumption of familiarity with Monte Carlo codes in general or with SCALE/KENO-VI in particular. The primer is designed to teach by example, with each example illustrating two or three features of SCALE/KENO-VI that are useful in criticality analyses. The primer is based on SCALE 6, which includes the Graphically Enhanced Editing Wizard (GeeWiz) Windows user interface. Each example uses GeeWiz to provide the framework for preparing input data and viewing output results. Starting with a Quickstart section, the primer gives an overview of the basic requirements for SCALE/KENO-VI input and allows the user to quickly run a simple criticality problem with SCALE/KENO-VI. The sections that follow Quickstart include a list of basic objectives at the beginning that identifies the goal of the section and the individual SCALE/KENO-VI features that are covered in detail in the sample problems in that section. Upon completion of the primer, a new user should be comfortable using GeeWiz to set up criticality problems in SCALE/KENO-VI. The primer provides a starting point for the criticality safety analyst who uses SCALE/KENO-VI. Complete descriptions are provided in the SCALE/KENO-VI manual. Although the primer is self-contained, it is intended as a companion volume to the SCALE/KENO-VI documentation. (The SCALE manual is provided on the SCALE installation DVD.) The primer provides specific examples of

Cranial mononeuropathy VI

Science.gov (United States)

... Abducens palsy; Lateral rectus palsy; VIth nerve palsy; Cranial nerve VI palsy; Sixth nerve palsy; Neuropathy - sixth nerve ... Cranial mononeuropathy VI is damage to the sixth cranial nerve. This nerve is also called the abducens nerve. ...

Chromium(VI) generation in vadose zone soils and alluvial sediments of the southwestern Sacramento Valley, California: a potential source of geogenic Cr(VI) to groundwater

Science.gov (United States)

Mills, Christopher T.; Morrison, Jean M.; Goldhaber, Martin B.; Ellefsen, Karl J.

2011-01-01

Concentrations of geogenic Cr(VI) in groundwater that exceed the World Health Organization’s maximum contaminant level for drinking water (50 μg L−1) occur in several locations globally. The major mechanism for mobilization of this Cr(VI) at these sites is the weathering of Cr(III) from ultramafic rocks and its subsequent oxidation on Mn oxides. This process may be occurring in the southern Sacramento Valley of California where Cr(VI) concentrations in groundwater can approach or exceed 50 μg L−1. To characterize Cr geochemistry in the area, samples from several soil auger cores (approximately 4 m deep) and drill cores (approximately 25 m deep) were analyzed for total concentrations of 44 major, minor and trace elements, Cr associated with labile Mn and Fe oxides, and Cr(VI). Total concentrations of Cr in these samples ranged from 140 to 2220 mg per kg soil. Between 9 and 70 mg per kg soil was released by selective extractions that target Fe oxides, but essentially no Cr was associated with the abundant reactive Mn oxides (up to ~1000 mg hydroxylamine-reducible Mn per kg soil was present). Both borehole magnetic susceptibility surveys performed at some of the drill core sites and relative differences between Cr released in a 4-acid digestion versus total Cr (lithium metaborate fusion digestion) suggest that the majority of total Cr in the samples is present in refractory chromite minerals transported from ultramafic exposures in the Coast Range Mountains. Chromium(VI) in the samples studied ranged from 0 to 42 μg kg−1, representing a minute fraction of total Cr. Chromium(VI) content was typically below detection in surface soils (top 10 cm) where soil organic matter was high, and increased with increasing depth in the soil auger cores as organic matter decreased. Maximum concentrations of Cr(VI) were up to 3 times greater in the deeper drill core samples than the shallow auger cores. Although Cr(VI) in these vadose zone soils and sediments was only a

A survey of Cr(VI) contamination of surface water in the proximity of ...

African Journals Online (AJOL)

2013-07-30

Jul 30, 2013 ... In this study, Cr(VI) levels present in surface water within the vicinity of ferrochrome smelters located in .... flict in literature pertaining to the toxicity or carcinogenicity ..... Due to the potential human health risks associated with.

Natural and man-made hexavalent chromium, Cr(VI), in groundwater near a mapped plume, Hinkley, California—study progress as of May 2017, and a summative-scale approach to estimate background Cr(VI) concentrations

Science.gov (United States)

Izbicki, John A.; Groover, Krishangi D.

2018-03-22

This report describes (1) work done between January 2015 and May 2017 as part of the U.S. Geological Survey (USGS) hexavalent chromium, Cr(VI), background study and (2) the summative-scale approach to be used to estimate the extent of anthropogenic (man-made) Cr(VI) and background Cr(VI) concentrations near the Pacific Gas and Electric Company (PG&E) natural gas compressor station in Hinkley, California. Most of the field work for the study was completed by May 2017. The summative-scale approach and calculation of Cr(VI) background were not well-defined at the time the USGS proposal for the background Cr(VI) study was prepared but have since been refined as a result of data collected as part of this study. The proposed summative scale consists of multiple items, formulated as questions to be answered at each sampled well. Questions that compose the summative scale were developed to address geologic, hydrologic, and geochemical constraints on Cr(VI) within the study area. Each question requires a binary (yes or no) answer. A score of 1 will be assigned for an answer that represents data consistent with anthropogenic Cr(VI); a score of –1 will be assigned for an answer that represents data inconsistent with anthropogenic Cr(VI). The areal extent of anthropogenic Cr(VI) estimated from the summative-scale analyses will be compared with the areal extent of anthropogenic Cr(VI) estimated on the basis of numerical groundwater flow model results, along with particle-tracking analyses. On the basis of these combined results, background Cr(VI) values will be estimated for “Mojave-type” deposits, and other deposits, in different parts of the study area outside the summative-scale mapped extent of anthropogenic Cr(VI).

Chromium(VI) generation in vadose zone soils and alluvial sediments of the southwestern Sacramento Valley, California: A potential source of geogenic Cr(VI) to groundwater

International Nuclear Information System (INIS)

Mills, Christopher T.; Morrison, Jean M.; Goldhaber, Martin B.; Ellefsen, Karl J.

2011-01-01

Highlights: → Southern Sacramento Valley soil and sediment has abundant naturally-occurring Cr(III). → Cr(III) resides mainly in chromite but some is associated with clays and Fe oxides. → Cr(VI) is mostly absent in surface soil but ubiquitous in deeper soil and sediment. → Cr(VI) increased linearly with time during lab soil incubations with no additions. → Cation exchange processes resulted in greater Cr(VI) generation rates. - Abstract: Concentrations of geogenic Cr(VI) in groundwater that exceed the World Health Organization's maximum contaminant level for drinking water (50 μg L -1 ) occur in several locations globally. The major mechanism for mobilization of this Cr(VI) at these sites is the weathering of Cr(III) from ultramafic rocks and its subsequent oxidation on Mn oxides. This process may be occurring in the southern Sacramento Valley of California where Cr(VI) concentrations in groundwater can approach or exceed 50 μg L -1 . To characterize Cr geochemistry in the area, samples from several soil auger cores (approximately 4 m deep) and drill cores (approximately 25 m deep) were analyzed for total concentrations of 44 major, minor and trace elements, Cr associated with labile Mn and Fe oxides, and Cr(VI). Total concentrations of Cr in these samples ranged from 140 to 2220 mg per kg soil. Between 9 and 70 mg per kg soil was released by selective extractions that target Fe oxides, but essentially no Cr was associated with the abundant reactive Mn oxides (up to ∼1000 mg hydroxylamine-reducible Mn per kg soil was present). Both borehole magnetic susceptibility surveys performed at some of the drill core sites and relative differences between Cr released in a 4-acid digestion versus total Cr (lithium metaborate fusion digestion) suggest that the majority of total Cr in the samples is present in refractory chromite minerals transported from ultramafic exposures in the Coast Range Mountains. Chromium(VI) in the samples studied ranged from 0 to 42 �

Chromium(VI) generation in vadose zone soils and alluvial sediments of the southwestern Sacramento Valley, California: A potential source of geogenic Cr(VI) to groundwater

Energy Technology Data Exchange (ETDEWEB)

Mills, Christopher T., E-mail: cmills@usgs.gov [United States Geological Survey, Crustal Geophysics and Geochemistry Science Center, Denver Federal Center, MS 964D, Denver, CO 80225 (United States); Morrison, Jean M.; Goldhaber, Martin B.; Ellefsen, Karl J. [United States Geological Survey, Crustal Geophysics and Geochemistry Science Center, Denver Federal Center, MS 964D, Denver, CO 80225 (United States)

2011-08-15

Highlights: > Southern Sacramento Valley soil and sediment has abundant naturally-occurring Cr(III). > Cr(III) resides mainly in chromite but some is associated with clays and Fe oxides. > Cr(VI) is mostly absent in surface soil but ubiquitous in deeper soil and sediment. > Cr(VI) increased linearly with time during lab soil incubations with no additions. > Cation exchange processes resulted in greater Cr(VI) generation rates. - Abstract: Concentrations of geogenic Cr(VI) in groundwater that exceed the World Health Organization's maximum contaminant level for drinking water (50 {mu}g L{sup -1}) occur in several locations globally. The major mechanism for mobilization of this Cr(VI) at these sites is the weathering of Cr(III) from ultramafic rocks and its subsequent oxidation on Mn oxides. This process may be occurring in the southern Sacramento Valley of California where Cr(VI) concentrations in groundwater can approach or exceed 50 {mu}g L{sup -1}. To characterize Cr geochemistry in the area, samples from several soil auger cores (approximately 4 m deep) and drill cores (approximately 25 m deep) were analyzed for total concentrations of 44 major, minor and trace elements, Cr associated with labile Mn and Fe oxides, and Cr(VI). Total concentrations of Cr in these samples ranged from 140 to 2220 mg per kg soil. Between 9 and 70 mg per kg soil was released by selective extractions that target Fe oxides, but essentially no Cr was associated with the abundant reactive Mn oxides (up to {approx}1000 mg hydroxylamine-reducible Mn per kg soil was present). Both borehole magnetic susceptibility surveys performed at some of the drill core sites and relative differences between Cr released in a 4-acid digestion versus total Cr (lithium metaborate fusion digestion) suggest that the majority of total Cr in the samples is present in refractory chromite minerals transported from ultramafic exposures in the Coast Range Mountains. Chromium(VI) in the samples studied ranged

Enzymatic reduction of U(VI) in groundwaters; Reduction enzymatique de U(VI) dans des eaux souterraines

Energy Technology Data Exchange (ETDEWEB)

Addelouas, A.; Gong, W. [Center for Radioactive Waste Management, Advanced Materials Laboratory, 1001 University, Albuquerque (United States); Lutze, W.; Nuttall, E. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering; Fritz, B.; Crovisier, J.L. [Centre National de la Recherche Scientifique (CNRS), 67 - Strasbourg (France). Centre de Sedimentologie et Geochimie de la Surface

1999-03-01

The use of enzymatic reduction of U(VI) in remediation of groundwater contaminated with U(VI) is receiving considerable attention. Certain strains of bacteria can combine the oxidation of an organic compound to the reduction of U(VI) to U(IV), which precipitates as uraninite. In the present study, we tested the reduction of U(VI) in groundwaters with various origins and compositions. In all groundwaters u(VI) was reduced by sulfate reducing bacteria that had been activated by ethanol and tri-metaphosphate. The reduction rate of U(VI) depends on sulfate concentration in water and the abundance of bacteria in the system. This work shows that bacteria capable of U(VI) reduction are ubiquitous in nature, and suggests the possibility of a large application of the enzymatic reduction of U(VI) for in situ clean up of groundwaters contaminated with uranium. (authors) 12 refs.

A SURVEY OF METAL LINES AT HIGH REDSHIFT. II. SDSS ABSORPTION LINE STUDIES-O VI LINE DENSITY, SPACE DENSITY, AND GAS METALLICITY AT zabs ∼ 3.0

International Nuclear Information System (INIS)

Frank, S.; Mathur, S.; Pieri, M.; York, D. G.

2010-01-01

We have analyzed a large data set of O VI absorber candidates found in the spectra of 3702 Sloan Digital Sky Survey (SDSS) quasars, focusing on a subsample of 387 active galactic nuclei sight lines with an average S/N ≥5.0, allowing for the detection of absorbers above a rest-frame equivalent width limit of W r ≥ 0.19 A for the O VI 1032 A component. Accounting for random interlopers mimicking an O VI doublet, we derive for the first time a secure lower limit for the redshift number density ΔN/Δz for redshifts z abs ≥ 2.8. With extensive Monte Carlo simulations, we quantify the losses of absorbers due to blending with the ubiquitous Lyα forest lines and estimate the success rate of retrieving each individual candidate as a function of its redshift, the emission redshift of the quasar, the strength of the absorber, and the measured signal-to-noise ratio (S/N) of the spectrum by modeling typical Lyman forest spectra. These correction factors allow us to derive the 'incompleteness and S/N-corrected' redshift number densities of O VI absorbers: ΔN O V I,c /Δz c (2.8 O V I,c /Δz c (3.2 O V I,c /Δz c (3.6 O V I (2.8 -8 h -1 . We show that the strong lines we probe account for over 65% of the mass in the O VI absorbers; the weak absorbers, while dominant in line number density, do not contribute significantly to the mass density. Making a conservative assumption about the ionization fraction, O VI /O, and adopting the Anders and Grevesse solar abundance values, we derive the mean metallicity of the gas probed in our search: ζ(2.8 -4 h, in good agreement with other studies. These results demonstrate that large spectroscopic data sets such as SDSS can play an important role in QSO absorption line studies, in spite of the relatively low resolution.

Constructing a survey over time: Audio-visual feedback and theatre sketches in rural Mali

Directory of Open Access Journals (Sweden)

Véronique Hertrich

2011-10-01

Full Text Available Knowledge dissemination is an emerging issue in population studies, both in terms of ethics and data quality. The challenge is especially important in long term follow-up surveys and it requires methodological imagination when the population is illiterate. The paper presents the dissemination project developed in a demographic surveillance system implemented in rural Mali over the last 20 years. After basic experience of document transfer, the feedback strategy was developed through audiovisual shows and theatre sketches. The advantages and drawbacks of these media are discussed, in terms of scientific communication and the construction of dialogue with the target population.

Groundwater contaminated with hexavalent chromium [Cr (VI)]: a health survey and clinical examination of community inhabitants (Kanpur, India).

Science.gov (United States)

Sharma, Priti; Bihari, Vipin; Agarwal, Sudhir K; Verma, Vipin; Kesavachandran, Chandrasekharan N; Pangtey, Balram S; Mathur, Neeraj; Singh, Kunwar Pal; Srivastava, Mithlesh; Goel, Sudhir K

2012-01-01

We assessed the health effects of hexavalent chromium groundwater contamination (from tanneries and chrome sulfate manufacturing) in Kanpur, India. The health status of residents living in areas with high Cr (VI) groundwater contamination (N = 186) were compared to residents with similar social and demographic features living in communities having no elevated Cr (VI) levels (N = 230). Subjects were recruited at health camps in both the areas. Health status was evaluated with health questionnaires, spirometry and blood hematology measures. Cr (VI) was measured in groundwater samples by diphenylcarbazide reagent method. Residents from communities with known Cr (VI) contamination had more self-reports of digestive and dermatological disorders and hematological abnormalities. GI distress was reported in 39.2% vs. 17.2% males (AOR = 3.1) and 39.3% vs. 21% females (AOR = 2.44); skin abnormalities in 24.5% vs. 9.2% males (AOR = 3.48) and 25% vs. 4.9% females (AOR = 6.57). Residents from affected communities had greater RBCs (among 30.7% males and 46.1% females), lower MCVs (among 62.8% males) and less platelets (among 68% males and 72% females) than matched controls. There were no differences in leucocytes count and spirometry parameters. Living in communities with Cr (VI) groundwater is associated with gastrointestinal and dermatological complaints and abnormal hematological function. Limitations of this study include small sample size and the lack of long term follow-up.

Assessing Feedback in a Mobile Videogame.

Science.gov (United States)

Brand, Leah; Beltran, Alicia; Hughes, Sheryl; O'Connor, Teresia; Baranowski, Janice; Nicklas, Theresa; Chen, Tzu-An; Dadabhoy, Hafza R; Diep, Cassandra S; Buday, Richard; Baranowski, Tom

2016-06-01

Player feedback is an important part of serious games, although there is no consensus regarding its delivery or optimal content. "Mommio" is a serious game designed to help mothers motivate their preschoolers to eat vegetables. The purpose of this study was to assess optimal format and content of player feedback for use in "Mommio." The current study posed 36 potential "Mommio" gameplay feedback statements to 20 mothers using a Web survey and interview. Mothers were asked about the meaning and helpfulness of each feedback statement. Several themes emerged upon thematic analysis, including identifying an effective alternative in the case of corrective feedback, avoiding vague wording, using succinct and correct grammar, avoiding provocation of guilt, and clearly identifying why players' game choice was correct or incorrect. Guidelines are proposed for future feedback statements.

Unregulated provider perceptions of audit and feedback reports in long-term care: cross-sectional survey findings from a quality improvement intervention.

Science.gov (United States)

Fraser, Kimberly D; O'Rourke, Hannah M; Baylon, Melba Andrea B; Boström, Anne-Marie; Sales, Anne E

2013-02-13

Audit with feedback is a moderately effective approach for improving professional practice in other health care settings. Although unregulated caregivers give the majority of direct care in long-term care settings, little is known about how they understand and perceive feedback reports because unregulated providers have not been directly targeted to receive audit with feedback in quality improvement interventions in long-term care. The purpose of this paper is to describe unregulated care providers' perceptions of usefulness of a feedback report in four Canadian long-term care facilities. We delivered monthly feedback reports to unregulated care providers for 13 months in 2009-2010. The feedback reports described a unit's performance in relation to falls, depression, and pain as compared to eight other units in the study. Follow-up surveys captured participant perceptions of the feedback report. We conducted descriptive analyses of the variables related to participant perceptions and multivariable logistic regression to assess the association between perceived usefulness of the feedback report and a set of independent variables. The vast majority (80%) of unregulated care providers (n = 171) who responded said they understood the reports. Those who discussed the report with others and were interested in other forms of data were more likely to find the feedback report useful for making changes in resident care. This work suggests that unregulated care providers can understand and feel positively about using audit with feedback reports to make changes to resident care. Further research should explore ways to promote fuller engagement of unregulated care providers in decision-making to improve quality of care in long-term care settings.

Force Modeling, Identification, and Feedback Control of Robot-Assisted Needle Insertion: A Survey of the Literature

Directory of Open Access Journals (Sweden)

Chongjun Yang

2018-02-01

Full Text Available Robot-assisted surgery is of growing interest in the surgical and engineering communities. The use of robots allows surgery to be performed with precision using smaller instruments and incisions, resulting in shorter healing times. However, using current technology, an operator cannot directly feel the operation because the surgeon-instrument and instrument-tissue interaction force feedbacks are lost during needle insertion. Advancements in force feedback and control not only help reduce tissue deformation and needle deflection but also provide the surgeon with better control over the surgical instruments. The goal of this review is to summarize the key components surrounding the force feedback and control during robot-assisted needle insertion. The literature search was conducted during the middle months of 2017 using mainstream academic search engines with a combination of keywords relevant to the field. In total, 166 articles with valuable contents were analyzed and grouped into five related topics. This survey systemically summarizes the state-of-the-art force control technologies for robot-assisted needle insertion, such as force modeling, measurement, the factors that influence the interaction force, parameter identification, and force control algorithms. All studies show force control is still at its initial stage. The influence factors, needle deflection or planning remain open for investigation in future.

Force Modeling, Identification, and Feedback Control of Robot-Assisted Needle Insertion: A Survey of the Literature.

Science.gov (United States)

Yang, Chongjun; Xie, Yu; Liu, Shuang; Sun, Dong

2018-02-12

Robot-assisted surgery is of growing interest in the surgical and engineering communities. The use of robots allows surgery to be performed with precision using smaller instruments and incisions, resulting in shorter healing times. However, using current technology, an operator cannot directly feel the operation because the surgeon-instrument and instrument-tissue interaction force feedbacks are lost during needle insertion. Advancements in force feedback and control not only help reduce tissue deformation and needle deflection but also provide the surgeon with better control over the surgical instruments. The goal of this review is to summarize the key components surrounding the force feedback and control during robot-assisted needle insertion. The literature search was conducted during the middle months of 2017 using mainstream academic search engines with a combination of keywords relevant to the field. In total, 166 articles with valuable contents were analyzed and grouped into five related topics. This survey systemically summarizes the state-of-the-art force control technologies for robot-assisted needle insertion, such as force modeling, measurement, the factors that influence the interaction force, parameter identification, and force control algorithms. All studies show force control is still at its initial stage. The influence factors, needle deflection or planning remain open for investigation in future.

Using Screencasts to Enhance Assessment Feedback: Students' Perceptions and Preferences

Science.gov (United States)

Marriott, Pru; Teoh, Lim Keong

2012-01-01

In the UK, assessment and feedback have been regularly highlighted by the National Student Survey as critical aspects that require improvement. An innovative approach to delivering feedback that has proved successful in non-business-related disciplines is the delivery of audio and visual feedback using screencast technology. The feedback on…

Uranium(VI) speciation by spectroscopy

International Nuclear Information System (INIS)

Meinrath, G.

1997-01-01

The application of UV-Vis and time-resolved laser-induced fluorescence (TRLF) spectroscopies to direct of uranium(VI) in environmental samples offers various prospects that have, however, serious limitations. While UV-Vis spectroscopy is probably not sensitive enough to detect uranium(VI) species in the majority of environmental samples, TRLFS is principially able to speciate uranium(VI) at very low concentration levels in the nanomol range. Speciation by TRLFS can be based on three parameters: excitation spectrum, emission spectrum and lifetime of the fluorescence emission process. Due to quenching effects, the lifetime may not be expected to be as characteristics as, e.g., the emission spectrum. Quenching of U(VI) fluorescence by reaction with organic substances, inorganic ions and formation of carbonate radicals is one important limiting factor in the application of U(VI) fluorescence spectroscopy. Fundamental photophysical criteria are illustrated using UV-Vis and fluorescence spectra of U(VI) hydrolysis and carbonato species as examples. (author)

Developing 360 degree feedback system for KINS

Energy Technology Data Exchange (ETDEWEB)

Han, In Soo; Cheon, B. M.; Kim, T. H.; Ryu, J. H. [Chungman National Univ., Daejeon (Korea, Republic of)

2003-12-15

This project aims to investigate the feasibility of a 360 degree feedback systems for KINS and to design guiding rules and structures in implementing that systems. Literature survey, environmental analysis and questionnaire survey were made to ensure that 360 degree feedback is the right tool to improve performance in KINS. That review leads to conclusion that more readiness and careful feasibility review are needed before implementation of 360 degree feedback in KINS. Further the project suggests some guiding rules that can be helpful for successful implementation of that system in KINS. Those include : start with development, experiment with one department, tie it to a clear organization's goal, train everyone involve, make sure to try that system in an atmosphere of trust.

Developing 360 degree feedback system for KINS

International Nuclear Information System (INIS)

Han, In Soo; Cheon, B. M.; Kim, T. H.; Ryu, J. H.

2003-12-01

This project aims to investigate the feasibility of a 360 degree feedback systems for KINS and to design guiding rules and structures in implementing that systems. Literature survey, environmental analysis and questionnaire survey were made to ensure that 360 degree feedback is the right tool to improve performance in KINS. That review leads to conclusion that more readiness and careful feasibility review are needed before implementation of 360 degree feedback in KINS. Further the project suggests some guiding rules that can be helpful for successful implementation of that system in KINS. Those include : start with development, experiment with one department, tie it to a clear organization's goal, train everyone involve, make sure to try that system in an atmosphere of trust

Groundwater contaminated with hexavalent chromium [Cr (VI]: a health survey and clinical examination of community inhabitants (Kanpur, India.

Directory of Open Access Journals (Sweden)

Priti Sharma

Full Text Available BACKGROUND: We assessed the health effects of hexavalent chromium groundwater contamination (from tanneries and chrome sulfate manufacturing in Kanpur, India. METHODS: The health status of residents living in areas with high Cr (VI groundwater contamination (N = 186 were compared to residents with similar social and demographic features living in communities having no elevated Cr (VI levels (N = 230. Subjects were recruited at health camps in both the areas. Health status was evaluated with health questionnaires, spirometry and blood hematology measures. Cr (VI was measured in groundwater samples by diphenylcarbazide reagent method. RESULTS: Residents from communities with known Cr (VI contamination had more self-reports of digestive and dermatological disorders and hematological abnormalities. GI distress was reported in 39.2% vs. 17.2% males (AOR = 3.1 and 39.3% vs. 21% females (AOR = 2.44; skin abnormalities in 24.5% vs. 9.2% males (AOR = 3.48 and 25% vs. 4.9% females (AOR = 6.57. Residents from affected communities had greater RBCs (among 30.7% males and 46.1% females, lower MCVs (among 62.8% males and less platelets (among 68% males and 72% females than matched controls. There were no differences in leucocytes count and spirometry parameters. CONCLUSIONS: Living in communities with Cr (VI groundwater is associated with gastrointestinal and dermatological complaints and abnormal hematological function. Limitations of this study include small sample size and the lack of long term follow-up.

Diverse anaerobic Cr(VI) tolerant bacteria from Cr(VI)-contaminated 100H site at Hanford

Science.gov (United States)

Chakraborty, R.; Phan, R.; Lam, S.; Leung, C.; Brodie, E. L.; Hazen, T. C.

2007-12-01

Hexavalent Chromium [Cr(VI)] is a widespread contaminant found in soil, sediment, and ground water. Cr(VI) is more soluble, toxic, carcinogenic, and mutagenic compared to its reduced form Cr(III). In order to stimulate microbially mediated reduction of Cr(VI), a poly-lactate compound HRC was injected into the chromium contaminated aquifers at site 100H at Hanford. Based on the results of the bacterial community composition using high-density DNA microarray analysis of 16S rRNA gene products, we recently investigated the diversity of the dominant anaerobic culturable microbial population present at this site and their role in Cr(VI) reduction. Positive enrichments set up at 30°C using specific defined anaerobic media resulted in the isolation of an iron reducing isolate strain HAF, a sulfate reducing isolate strain HBLS and a nitrate reducing isolate, strain HLN among several others. Preliminary 16S rDNA sequence analysis identifies strain HAF as Geobacter metallireducens, strain HLN as Pseudomonas stutzeri and strain HBLS as a member of Desulfovibrio species. Strain HAF isolated with acetate as the electron donor utilized propionate, glycerol and pyruvate as alternative carbon sources, and reduced metals like Mn(IV) and Cr(VI). Growth was optimal at 37°C, pH of 6.5 and 0% salinity. Strain HLN isolated with lactate as electron donor utilized acetate, glycerol and pyruvate as alternative carbon sources, and reduced metals like Mn(IV) and Cr(VI). Optimal growth was observed at 37°C, at a pH of 7.5 and 0.3% salinity. Anaerobic active washed cell suspension of strain HLN reduced almost 95 micromolar Cr(VI) within 4 hours relative to controls. Further, with 100 micromolar Cr(VI) as the sole electron acceptor, cells of strain HLN grew to cell numbers of 4.05X 107/ml over a period of 24hrs after an initial lag, demonstrating direct enzymatic Cr(VI) reduction by this species. 10mM lactate served as the sole electron donor. These results demonstrate that Cr(VI

Survey of Digital Feedback Systems in High Current Storage Rings

International Nuclear Information System (INIS)

Teytelman, Dmitry

2003-01-01

In the last decade demand for brightness in synchrotron light sources and luminosity in circular colliders led to construction of multiple high current storage rings. Many of these new machines require feedback systems to achieve design stored beam currents. In the same time frame the rapid advances in the technology of digital signal processing allowed the implementation of these complex feedback systems. In this paper I concentrate on three applications of feedback to storage rings: orbit control in light sources, coupled-bunch instability control, and low-level RF control. Each of these applications is challenging in areas of processing bandwidth, algorithm complexity, and control of time-varying beam and system dynamics. I will review existing implementations as well as comment on promising future directions

Feedback authoring possibilities in web-based learning systems

NARCIS (Netherlands)

Vasilyeva, E.; De Bra, P.M.E.; Pechenizkiy, M.; Bonk, C.J.; et al., xx

2008-01-01

This paper surveys and analyses the feedback authoring possibilities in online assessment modules of the most popular Learning Management Systems (LMS) including Moodle, Sakai, and Blackboard. We consider the problem of authoring and support of tailored and personalized feedback and demonstrate how

Enzymatic reduction of U(VI) in groundwaters

International Nuclear Information System (INIS)

Addelouas, A.; Gong, W.; Lutze, W.; Nuttall, E.; Fritz, B.; Crovisier, J.L.

1999-01-01

The use of enzymatic reduction of U(VI) in remediation of groundwater contaminated with U(VI) is receiving considerable attention. Certain strains of bacteria can combine the oxidation of an organic compound to the reduction of U(VI) to U(IV), which precipitates as uraninite. In the present study, we tested the reduction of U(VI) in groundwaters with various origins and compositions. In all groundwaters u(VI) was reduced by sulfate reducing bacteria that had been activated by ethanol and tri-metaphosphate. The reduction rate of U(VI) depends on sulfate concentration in water and the abundance of bacteria in the system. This work shows that bacteria capable of U(VI) reduction are ubiquitous in nature, and suggests the possibility of a large application of the enzymatic reduction of U(VI) for in situ clean up of groundwaters contaminated with uranium. (authors)

Brugbar peer feedback: Instruktion og træning før vi slipper de studerende løs

DEFF Research Database (Denmark)

Hvass, Helle; Heger, Stine

2018-01-01

Om den rammesætning og instruktion som studerende har behov for, hvis peer feedback skal fungere som læringsaktivitet i praksis.......Om den rammesætning og instruktion som studerende har behov for, hvis peer feedback skal fungere som læringsaktivitet i praksis....

Enzymatic U(VI) reduction by Desulfosporosinus species

International Nuclear Information System (INIS)

Suzuki, Y.; Kelly, S.D.; Kemner, K.M.; Banfield, J.F.

2004-01-01

Here we tested U(VI) reduction by a Desulfosporosinus species (sp.) isolate and type strain (DSM 765) in cell suspensions (pH 7) containing 1 mM U(VI) and lactate, under an atmosphere containing N 2 -CO 2 -H 2 (90: 5: 5). Although neither Desulfosporosinus species (spp.) reduced U(VI) in cell suspensions with 0.25% Na-bicarbonate or 0.85% NaCl, U(VI) was reduced in these solutions by a control strain, desulfovibrio desulfuricans (ATCC 642). However, both Desulfosporosinus strains reduced U(VI) in cell suspensions depleted in bicarbonate and NaCl. No U(VI) reduction was observed without lactate and H 2 electron donors or with heat-killed cells, indicating enzymatic U(VI) reduction. Uranium(VI) reduction by both strains was inhibited when 1 mM CuCl 2 was added to the cell suspensions. Because the Desulfosporosinus DSM 765 does not contain cytochrome c 3 used by Desulfovibrio spp. to reduce U(VI), Desulfosporosinus species reduce uranium via a different enzymatic pathway. (orig.)

Kiintoainehäviöselvitys

OpenAIRE

Ylimys, Jussi

2014-01-01

Teoriaosassa käydään läpi yleisesti pyörrepuhdistuslaitoksen toimintaa sekä kiintoainehäviöitä paperi- ja kartonkitehtailla. Tämän opinnäytetyön tarkoituksena oli tutkia Metsä Boardin Kyröskosken tehtaan kiintoainehäviötä. Työssä selvitettiin, minkälaista kiintoainetta jätevesilaitokselle päätyy ja miksi. Selvityksen kohteena oli myös, missä kohteissa kiintoainehäviöt tarkalleen syntyvät ja kuinka paljon häviötä tapahtuu. Kahden edellä mainitun tiedon perusteella selvitettiin, kuinka palj...

Inspiring Teachers to Reflect and Ask for Feedback: An Interplay of Teachers' Self-Efficacy, Principals' Feedback, and Servant Leadership Characteristics

Science.gov (United States)

Birringer-Haig, Joan I.

2014-01-01

The goal of the study was to investigate how teachers' reflection and asking for feedback--critical aspects of teachers' professional growth--can be explained and stimulated by teachers' self-efficacy, principals' feedback, and servant leadership characteristics. A mixed-method study was conducted with data collected from surveys and interviews…

Peroxo complexes of molybdenum(VI), tungsten(VI), uranium(VI), zirconium(IV) and thorium(IV) ions containing tridentate Schiff bases derived from salicylaldehyde and amino acids

International Nuclear Information System (INIS)

Tarafder, M.T.H.; Khan, A.R.

1997-01-01

The synthesis of peroxo complexes of molybdenum(VI), tungsten(VI), uranium(VI), zirconium(IV), thorium(IV) and their possible oxygen transfer reactions is presented. An attempt has also been made to study the size of the metal ions and the electronic effect derived from the tridentate Schiff bases on the v 1 (O-O) mode of the complexes in their IR spectra

Observational Signatures Of Agn Feedback Across Cosmic Time

Science.gov (United States)

Wylezalek, Dominika

2017-06-01

While many compelling models of AGN feedback exist, there is no clear data-driven picture of how winds are launched, how they propagate through the galaxy and what impact they have on the galactic gas. Recent work suggests that AGN luminosity plays an important role. The following described projects focus on understanding the power, reach and impact of feedback processes exerted by AGN of different power. I first describe recent efforts in our group of relating feedback signatures in powerful quasars to the specific star formation rate in their host galaxies, where our results are consistent with the AGN having a `negative' impact through feedback on the galaxies' star formation history. Feedback signatures seem to be best observable in gas-rich galaxies where the coupling of the AGN-driven wind to the gas is strongest, in agreement with recent simulations. But how and where does this quenching happen? Is it accomplished through the mechanical action of jets or through nuclear winds driven by radiation pressure? Finally, I show that AGN signatures and AGN-driven winds can be easily hidden and not be apparent in the integrated spectrum of a galaxy hosting a low/intermediate-luminosity AGN. Using data from the new SDSS-IV MaNGA survey, we have developed a new AGN selection algorithm tailored to IFU data and we are uncovering a much more nuanced picture of AGN activity allowing us to discover AGN signatures at large distances from the galaxy center. This implies that large IFU surveys, such as the SDSS-IV MaNGA survey, might uncover many previously unknown AGN and feedback signatures related to them. Outflows and feedback from low- and intermediate-luminosity AGN might have been underestimated in the past but can potentially significantly contribute to the AGN/host-galaxy self-regulation.

Effective Instructor Feedback: Perceptions of Online Graduate Students

Directory of Open Access Journals (Sweden)

Beverley Getzlaf

2009-07-01

Full Text Available This descriptive study explored online graduate students' perceptions of effective instructor feedback. The objectives of the study were to determine the students’ perceptions of the content of effective instructor feedback (“what should be included in effective feedback?” and the process of effective instructor feedback (“how should effective feedback be provided?”. The participants were students completing health-related graduate courses offered exclusively online. Data were collected via a survey that included open ended questions inviting participants to share their perspectives regarding effective online instructor feedback. Thematic analysis revealed five major themes: student involvement/individualization, gentle guidance, being positively constructive, timeliness and future orientation. We conclude that effective instructor feedback has positive outcomes for the students. Future studies are warranted to investigate strategies to make feedback a mutual process between instructor and student that supports an effective feedback cycle.

ENDF-201, ENDF/B-VI summary documentation supplement 1, ENDF/HE-VI summary documentation

International Nuclear Information System (INIS)

McLane, V.

1996-12-01

The National Nuclear Data Center (NNDC) provides coordination for and serves as the secretariat to the Cross Section Evaluation Working Group (CSWEG). CSEWG is responsible for the oversight of the ENDF/B Evaluated Nuclear Data File. All data are checked and reviewed by CSEWG, and the file is maintained at the NNDC. For a description of the ENDF/B-VI file, see the ENDF-102 Data Formats and Procedures for the Evaluated Nuclear Data File ENDF-6. The purpose of this addendum to the ENDF/B-VI Summary Documentation is to provide documentation of Releases 1, 2, 3, and 4 for the ENDF/B-VI and ENDF/HE-VI evaluated nuclear data libraries. These releases contain many new and revised evaluations for the neutron, photo-atomic interaction, radioactive decay data, spontaneous fission product yield, neutron-induced fission product yield, thermal neutron scattering, proton, deuteron, and triton sublibraries. The summaries have been extracted mainly from the ENDF/B-VI File 1 comments (MT = 451), which have been checked, edited, and may also include supplementary information. Some summaries have been provided by the evaluators in electronic format, while others are extracted from reports on the evaluations. All references have been checked and corrected, or updated where appropriate. A list of the laboratories which have contributed evaluations used in ENDF/B-VI is given

ENDF-201, ENDF/B-VI summary documentation supplement 1, ENDF/HE-VI summary documentation

Energy Technology Data Exchange (ETDEWEB)

McLane, V.

1996-12-01

The National Nuclear Data Center (NNDC) provides coordination for and serves as the secretariat to the Cross Section Evaluation Working Group (CSWEG). CSEWG is responsible for the oversight of the ENDF/B Evaluated Nuclear Data File. All data are checked and reviewed by CSEWG, and the file is maintained at the NNDC. For a description of the ENDF/B-VI file, see the ENDF-102 Data Formats and Procedures for the Evaluated Nuclear Data File ENDF-6. The purpose of this addendum to the ENDF/B-VI Summary Documentation is to provide documentation of Releases 1, 2, 3, and 4 for the ENDF/B-VI and ENDF/HE-VI evaluated nuclear data libraries. These releases contain many new and revised evaluations for the neutron, photo-atomic interaction, radioactive decay data, spontaneous fission product yield, neutron-induced fission product yield, thermal neutron scattering, proton, deuteron, and triton sublibraries. The summaries have been extracted mainly from the ENDF/B-VI File 1 comments (MT = 451), which have been checked, edited, and may also include supplementary information. Some summaries have been provided by the evaluators in electronic format, while others are extracted from reports on the evaluations. All references have been checked and corrected, or updated where appropriate. A list of the laboratories which have contributed evaluations used in ENDF/B-VI is given.

24 CFR 971.11 - HOPE VI developments.

Science.gov (United States)

2010-04-01

... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false HOPE VI developments. 971.11... § 971.11 HOPE VI developments. Developments with HOPE VI implementation grants that have approved HOPE... with reasonable revitalization plans. Future HUD actions to approve or deny proposed HOPE VI...

Does source matter? Nurses' and Physicians' perceptions of interprofessional feedback.

Science.gov (United States)

van Schaik, Sandrijn M; O'Sullivan, Patricia S; Eva, Kevin W; Irby, David M; Regehr, Glenn

2016-02-01

Receptiveness to interprofessional feedback, which is important for optimal collaboration, may be influenced by 'in-group or out-group' categorisation, as suggested by social identity theory. We used an experimental design to explore how nurses and resident physicians perceive feedback from people within and outside their own professional group. Paediatric residents and nurses participated in a simulation-based team exercise. Two nurses and two physicians wrote anonymous performance feedback for each participant. Participants each received a survey containing these feedback comments with prompts to rate (i) the usefulness (ii) the positivity and (iii) their agreement with each comment. Half of the participants received feedback labelled with the feedback provider's profession (two comments correctly labelled and two incorrectly labelled). Half received unlabelled feedback and were asked to guess the provider's profession. For each group, we performed separate three-way anovas on usefulness, positivity and agreement ratings to examine interactions between the recipient's profession, actual provider profession and perceived provider profession. Forty-five out of 50 participants completed the survey. There were no significant interactions between profession of the recipient and the actual profession of the feedback provider for any of the 3 variables. Among participants who guessed the source of the feedback, we found significant interactions between the profession of the feedback recipient and the guessed source of the feedback for both usefulness (F1,48 = 25.6; p feedback they guessed to be from nurses were higher than ratings of feedback they guessed to be from physicians, and vice versa. Among participants who received labelled feedback, we noted a similar interaction between the profession of the feedback recipient and labelled source of feedback for usefulness ratings (F1,92 = 4.72; p feedback to the in-group than to the out-group. This finding has potential

Technology-derived storage solutions for stabilizing insulin in extreme weather conditions I: the ViViCap-1 device.

Science.gov (United States)

Pfützner, Andreas; Pesach, Gidi; Nagar, Ron

2017-06-01

Injectable life-saving drugs should not be exposed to temperatures 30°C/86°F. Frequently, weather conditions exceed these temperature thresholds in many countries. Insulin is to be kept at 4-8°C/~ 39-47°F until use and once opened, is supposed to be stable for up to 31 days at room temperature (exception: 42 days for insulin levemir). Extremely hot or cold external temperature can lead to insulin degradation in a very short time with loss of its glucose-lowering efficacy. Combined chemical and engineering solutions for heat protection are employed in ViViCap-1 for disposable insulin pens. The device works based on vacuum insulation and heat consumption by phase-change material. Laboratory studies with exposure of ViViCap-1 to hot outside conditions were performed to evaluate the device performance. ViViCap-1 keeps insulin at an internal temperature phase-change process and 'recharges' the device for further use. ViViCap-1 performed within its specifications. The small and convenient device maintains the efficacy and safety of using insulin even when carried under hot weather conditions.

Ensuring consistency and persistence to the Quality Information Model - The role of the GeoViQua Broker

Science.gov (United States)

Bigagli, Lorenzo; Papeschi, Fabrizio; Nativi, Stefano; Bastin, Lucy; Masó, Joan

2013-04-01

GeoViQua (QUAlity aware VIsualisation for the Global Earth Observation System of Systems) is an FP7 project aiming at complementing the Global Earth Observation System of Systems (GEOSS) with rigorous data quality specifications and quality-aware capabilities, in order to improve reliability in scientific studies and policy decision-making. GeoViQua main scientific and technical objective is to enhance the GEOSS Common Infrastructure (GCI) providing the user community with innovative quality-aware search and visualization tools, which will be integrated in the GEOPortal, as well as made available to other end-user interfaces. To this end, GeoViQua will promote the extension of the current standard metadata for geographic information with accurate and expressive quality indicators. The project will also contribute to the definition of a quality label, the GEOLabel, reflecting scientific relevance, quality, acceptance and societal needs. The concept of Quality Information is very broad. When talking about the quality of a product, this is not limited to geophysical quality but also includes concepts like mission quality (e.g. data coverage with respect to planning). In general, it provides an indication of the overall fitness for use of a specific type of product. Employing and extending several ISO standards such as 19115, 19157 and 19139, a common set of data quality indicators has been selected to be used within the project. The resulting work, in the form of a data model, is expressed in XML Schema Language and encoded in XML. Quality information can be stated both by data producers and by data users, actually resulting in two conceptually distinct data models, the Producer Quality model and the User Quality model (or User Feedback model). A very important issue concerns the association between the quality reports and the affected products that are target of the report. This association is usually achieved by means of a Product Identifier (PID), but actually just

Measuring Galactic Feedback with the Origins Space Telescope

Science.gov (United States)

Armus, Lee; Bolatto, Alberto; Pope, Alexandra; Bradford, Charles Matt; Origins Space Telescope Science and Technology Definition Team

2018-01-01

Since a significant fraction of star formation and black hole growth occurs behind dust, our understanding of how and why galaxies evolve will remain incomplete until deep, wide area spectroscopic surveys in the FIRcan be carried out from space. The Origins Space Telescope (OST), a mission concept being studied for presentation to the 2020 Decadal Survey, represents an enormous leap over any existing infrared mission, and will uniquely measure black hole growth and star formation in dusty galaxies over more than 95% of cosmic history. Energetic feedback from AGN, young stars, and supernovae can regulate galaxy growth over a wide range in mass and be important for the enrichment of the interstellar and circumgalactic medium, yet the existence and type of feedback as a function of redshift, luminosity, and environment is poorly constrained. With wide wavelength coverage (5-600 microns), a large primary mirror actively cooled to ~4K, and a capable suite of imagers and spectrometers, OST will be an extremely sensitive probe of the effects of feedback on the multi-phase ISM in galaxies, through measurement of key feedback tracers such as OH and H2O absorption lines, fine structure emission lines, and PAH dust features. With OST we can directly observe the role of feedback in quenching galaxies, derive the wind kinetic energy and mass outflow rates, and correlate these with key galaxy properties (AGN or starburst power, environment, mass, age). In this poster we will explain how blind and targeted surveys with OST will have an enormous impact on our understanding of the duty cycle and basic physical properties of feedback in AGN and starburst galaxies over the last 12 Gyr.

Reduction of ferrate(VI) and oxidation of cyanate in a Fe(VI)-TiO2-UV-NCO- system.

Science.gov (United States)

Winkelmann, Kurt; Sharma, Virender K; Lin, Yekaterina; Shreve, Katherine A; Winkelmann, Catherine; Hoisington, Laura J; Yngard, Ria A

2008-08-01

The aqueous photocatalytic degradation of cyanate (NCO(-)), which is a long-lived neurotoxin formed during the remediation of cyanide in industrial waste streams, was studied in the ferrate(VI)-UV-TiO2-NCO(-) system. Kinetics measurements of the photocatalytic reduction of ferrate(VI) were carried out as a function of [NCO(-)], [ferrate(VI)], [O(2)], light intensity (I(o)), and amount of TiO2 in suspensions at pH 9.0. The photocatalytic reduction rate of ferrate(VI) in the studied system can be expressed as -d[Fe(VI)]/dt=kI(o)(0.5) [NCO(-)] [TiO2]. The rate of photocatalytic oxidation of cyanate with ferrate(VI) was greater than the rate in the analogous system without ferrate(VI). The possibility of involvement of reactive ferrate(V) species for this enhancement was determined by studying the reactivity of ferrate(V) with NCO(-) in a homogeneous solution using a premix pulse radiolysis technique. The rate constant for the reaction of ferrate(V) and NCO(-) in alkaline medium was estimated to be (9.60+/-0.07) x 10(2) M(-1) s(-1), which is much slower than the ferrate(VI) self-decomposition reaction (k approximately 10(7) M(-1) s(-1)). An analysis of the kinetic data in the Fe(VI)-UV-TiO2-NCO(-) system suggests that ferrate(V) is not directly participating in the oxidation of cyanate. Possible reactions in the system are presented to explain results of ferrate(VI) reduction and oxidation of cyanate.

Vi har intet lært - hvornår lærer vi det?

DEFF Research Database (Denmark)

Sodemann, Morten

2016-01-01

WHO anså fra i går ikke længere ebola for at være en trussel mod global folkesundhed, så fra i dag er kameraerne slukket i Vestafrika og vi er tilbage hvor vi startede. SDG målene skal have et dansk udtryk, men hvad er de danske kompetencer på globalt plan når sundhed ikke længere er en kerneakti......WHO anså fra i går ikke længere ebola for at være en trussel mod global folkesundhed, så fra i dag er kameraerne slukket i Vestafrika og vi er tilbage hvor vi startede. SDG målene skal have et dansk udtryk, men hvad er de danske kompetencer på globalt plan når sundhed ikke længere er en...

The new geographic information system in ETVA VI.PE.

Science.gov (United States)

Xagoraris, Zafiris; Soulis, George

2016-08-01

ETVA VI.PE. S.A. is a member of the Piraeus Bank Group of Companies and its activities include designing, developing, exploiting and managing Industrial Areas throughout Greece. Inside ETVA VI.PE.'s thirty-one Industrial Parks there are currently 2,500 manufacturing companies established, with 40,000 employees and € 2.5 billion of invested funds. In each one of the industrial areas ETVA VI.PE guarantees the companies industrial lots of land (sites) with propitious building codes and complete infrastructure networks of water supply, sewerage, paved roads, power supply, communications, cleansing services, etc. The development of Geographical Information System for ETVA VI.PE.'s Industrial Parks started at the beginning of 1992 and consists of three subsystems: Cadastre, that manages the information for the land acquisition of Industrial Areas; Street Layout - Sites, that manages the sites sold to manufacturing companies; Networks, that manages the infrastructure networks (roads, water supply, sewerage etc). The mapping of each Industrial Park is made incorporating state-of-the-art photogrammetric, cartographic and surveying methods and techniques. Passing through the phases of initial design (hybrid GIS) and system upgrade (integrated Gis solution with spatial database), the system is currently operating on a new upgrade (integrated gIS solution with spatial database) that includes redesigning and merging the system's database schemas, along with the creation of central security policies, and the development of a new web GIS application for advanced data entry, highly customisable and standard reports, and dynamic interactive maps. The new GIS bring the company to advanced levels of productivity and introduce the new era for decision making and business management.

Peer observation and feedback of resident teaching.

Science.gov (United States)

Snydman, Laura; Chandler, Daniel; Rencic, Joseph; Sung, Yung-Chi

2013-02-01

Resident doctors (residents) play a significant role in the education of medical students. Morning work rounds provide an optimal venue to assess resident teaching. The purpose of this study was to assess the feasibility of peer observation of resident work rounds, to evaluate resident perceptions of peer observation and to evaluate resident perceptions of peer feedback.   Twenty-four internal medicine residents were simultaneously observed by an attending physician and a peer while teaching during work rounds (between August2008 and May 2009). At year-end, residents received a survey to characterise their attitudes towards peer observation and feedback. Twenty-one residents (87.5%) completed the survey. Half (52.4%) felt that participating in the peer observation study stimulated their interest in teaching during work rounds. Prior to participation in the study, fewer than half (42.9%) felt comfortable being observed by their peers, compared with 71.4 percent after participation (p=0.02). The proportion of residents who felt comfortable giving feedback to peers increased from 26.3 to 65.0percent (p=0.004), and the proportion of residents who felt comfortable receiving feedback from peers increased from 76.2 to 95.2 percent (p=0.02). Peer observation and feedback of resident teaching during work rounds is feasible and rewarding for the residents involved. Comfort with regards to being observed by peers, with receiving feedback from peers and with giving feedback to peers significantly increased after the study. Most residents reported changes in their teaching behaviour resulting from feedback. Residents felt that observing a peer teach on work rounds was one of the most useful activities to improve their own teaching on work rounds. © Blackwell Publishing Ltd 2013.

Simultaneous Feedback Models with Macro-Comparative Cross-Sectional Data

Directory of Open Access Journals (Sweden)

Nate Breznau

2018-06-01

Full Text Available Social scientists often work with theories of reciprocal causality. Sometimes theories suggest that reciprocal causes work simultaneously, or work on a time-scale small enough to make them appear simultaneous. Researchers may employ simultaneous feedback models to investigate such theories, although the practice is rare in cross-sectional survey research. This paper discusses the certain conditions that make these models possible if not desirable using such data. This methodological excursus covers the construction of simultaneous feedback models using a structural equation modeling perspective. This allows the researcher to test if a simultaneous feedback theory fits survey data, test competing hypotheses and engage in macro-comparisons. This paper presents methods in a manner and language amenable to the practicing social scientist who is not a statistician or matrix mathematician. It demonstrates how to run models using three popular software programs (MPlus, Stata and R, and an empirical example using International Social Survey Program data.

Effect of uranium (VI) on the growth of yeast and influence of metabolism of yeast on adsorption of U (VI)

International Nuclear Information System (INIS)

Sakamoto, Fuminori; Ohnuki, Toshihiko; Kozai, Naofumi; Wakai, Eiichi; Francis, A.J.

2005-01-01

We have carried out the growth experiments of 3 strains of yeast in a medium containing uranium (VI) to elucidate the effect of U (VI) on the growth of microorganisms. Hansenula fabianii J640 grew in the liquid medium containing 0.1 mM U (VI) at lower rate than the control, but Saccharomyces cerevisiae did not grow under this condition. The H. fabianii J640 pre-cultured for 21 h in the liquid medium without U (VI) grew even after the exposure to 1 mM U (VI), but did not grow without pre-cultivation. For the pre-cultured H. fabianii J640, radioactivity of U in the medium was the same as the initial one for 110 h, and then gradually decreased. TEM-EDS analysis of H. fabianii J640 exposed to 1 mM U (VI) for 165 h showed accumulation of U (VI) on the cells. When H. fabianii J640 was not pre-cultured, radioactivity of U in the medium was lower than the initial one. These results indicated that U (VI) inhibits the growth of yeast, and that the adsorption of U (VI) by the cells depends on the metabolism of yeast. (author)

Preparation and properties of N-Phenylbutyrohydroxamic acid and N-p-Chlorophenylbutyrohydroxamic acid and their uses as extracting agents for Chromium (VI), Molybdenum (VI), Titanium (IV) and Uranium (VI)

Energy Technology Data Exchange (ETDEWEB)

Abu Elnour, Sawsan Hassan [Department of Chemistry, Faculty of Science, University of Khartoum, Khartoum (Sudan)

1993-05-01

Two lignads, N-phenylbutyrohydroxamic acid (1), N-p-chlorophenylbutyryl chloride with {beta} phenyl-hydroylamine and N-p-chlorophenylhydroxylamine, respectively. The acids prepared were identified and characterised through their reactions with Vanadiun (V) and iron (III), their melting points, infra-red spectra and nitrogen content. The extractive properties of these acids towards the metals Cr (VI), Mo (VI), Ti (IV) and U (VI) were examined at different PH values. The percentage of maximum extraction with the two acids was found to be as follows : for Cr (VI) at PH 1, (100%) for both acids, Mo (VI) at PH 2 (33.34%) with acid (I) and (16.67%) with acid (II) and U (VI) at PH 6 (72%) with acid (I) and (76%) with acid (II). The metal: Ligand complexes ratios were determined by using the continuous variation method, the ratio of the two ligands with four metals was found to be 1:2. Finally the suitability of the two acids for spectrophotometric determination of four metals was examined.(Author) 90 refs. , 24 tabs. , 24 figs

Preparation and properties of N-Phenylbutyrohydroxamic acid and N-p-Chlorophenylbutyrohydroxamic acid and their uses as extracting agents for Chromium (VI), Molybdenum (VI), Titanium (IV) and Uranium (VI)

International Nuclear Information System (INIS)

Abu Elnour, Sawsan Hassan

1993-05-01

Two lignads, N-phenylbutyrohydroxamic acid (1), N-p-chlorophenylbutyryl chloride with β phenyl-hydroylamine and N-p-chlorophenylhydroxylamine, respectively. The acids prepared were identified and characterised through their reactions with Vanadiun (V) and iron (III), their melting points, infra-red spectra and nitrogen content. The extractive properties of these acids towards the metals Cr (VI), Mo (VI), Ti (IV) and U (VI) were examined at different PH values. The percentage of maximum extraction with the two acids was found to be as follows : for Cr (VI) at PH 1, (100%) for both acids, Mo (VI) at PH 2 (33.34%) with acid (I) and (16.67%) with acid (II) and U (VI) at PH 6 (72%) with acid (I) and (76%) with acid (II). The metal: Ligand complexes ratios were determined by using the continuous variation method, the ratio of the two ligands with four metals was found to be 1:2. Finally the suitability of the two acids for spectrophotometric determination of four metals was examined.(Author)

Lizards and Amphisbaenians, municipality of Viçosa, state of Minas Gerais, southeastern Brazil

Directory of Open Access Journals (Sweden)

Rodrigues, A. C.

2009-01-01

Full Text Available We performed a survey of lizards and amphisbaenians from municipality of Viçosa, in Atlantic Forest from state ofMinas Gerais, southeastern Brazil, based on data of the herpetological collections of Museu de Zoologia João Moojen,Universidade Federal de Viçosa, and Museu de Zoologia, Universidade de São Paulo. One hundred and forty sixspecimens of 14 species were analyzed, belonging to the following families: Amphisbaenidae, Anguidae, Gekkonidae,Gymnophthalmidae, Leiosauridae, Polychrotidae, Scincidae, Teiidae and Tropiduridae. We hope to supply basicinformation that helps to understand species distribution of this group in the Atlantic Forest of Minas Gerais andsoutheastern Brazil.

Nursing home administrators’ perspectives on a study feedback report: a cross sectional survey

Directory of Open Access Journals (Sweden)

Boström Anne-Marie

2012-09-01

Full Text Available Abstract Background This project is part of the Translating Research in Elder Care (TREC program of research, a multi-level and longitudinal research program being conducted in 36 nursing homes in three Canadian Prairie Provinces. The overall goal of TREC is to improve the quality of care for older persons living in nursing homes and the quality of work life for care providers. The purpose of this paper is to report on development and evaluation of facility annual reports (FARs from facility administrators’ perspectives on the usefulness, meaningfulness, and understandability of selected data from the TREC survey. Methods A cross sectional survey design was used in this study. The feedback reports were developed in collaboration with participating facility administrators. FARs presented results in four contextual areas: workplace culture, feedback processes, job satisfaction, and staff burnout. Six weeks after FARs were mailed to each administrator, we conducted structured telephone interviews with administrators to elicit their evaluation of the FARs. Administrators were also asked if they had taken any actions as a result of the FAR. Descriptive and inferential statistics, as well as content analysis for open-ended questions, were used to summarize findings. Results Thirty-one facility administrators (representing thirty-two facilities participated in the interviews. Six administrators had taken action and 18 were planning on taking action as a result of FARs. The majority found the four contextual areas addressed in FAR to be useful, meaningful, and understandable. They liked the comparisons made between data from years one and two and between their facility and other TREC study sites in their province. Twenty-two indicated that they would like to receive information on additional areas such as aggressive behaviours of residents and information sharing. Twenty-four administrators indicated that FARs contained enough information, while eight

Use of Video-Projected Structured Clinical Examination (ViPSCE) instead of the traditional oral (Viva) examination in the assessment of final year medical students.

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El Shallaly, Gamal; Ali, Eltayeb

2004-03-01

Assessment of medical students using the traditional oral (viva) system has been marred by being highly subjective, non-structured, and biased. The use of the objective structured clinical examination (OSCE) would circumvent these disadvantages. The OSCE is, however, costly and time-consuming particularly if used for assessment of large numbers of students. The need for another form of examination that enjoys the advantages of the OSCE while avoiding its disadvantages in the face of limited resources has been the inspiration behind this innovative approach. (1) To identify the characteristics of the new Video-Projected Structured Clinical Examination (ViPSCE). (2) To compare the acceptability of ViPSCE and OSCE by students and tutors. (3) To compare the time-effectiveness of ViPSCE and OSCE. We used a slide video projection to assess the surgical knowledge, problem solving and management abilities of 112 final year medical students at Alazhari University, Khartoum, Sudan. Students completed evaluation forms at the end of the examination. The administration of the ViPSCE was smooth and straightforward. Feedback of the students showed that they preferred the ViPSCE to both traditional oral (viva) examination and OSCE. The examination time was 2 hours using video projection compared to the 6 hours that it used to take a class of 112 students to complete a classical OSCE. The ViPSCE is a better replacement for the traditional oral exam. It is much less time- consuming than traditional OSCE.

Different roles of ROS and Nrf2 in Cr(VI)-induced inflammatory responses in normal and Cr(VI)-transformed cells

Energy Technology Data Exchange (ETDEWEB)

Roy, Ram Vinod; Pratheeshkumar, Poyil; Son, Yong-Ok; Wang, Lei [Center for Research on Environmental Disease, University of Kentucky, 1095 VA Drive, Lexington, KY 40536 (United States); Department of Toxicology and Cancer Biology, College of Medicine, University of Kentucky, 1095 VA Drive, Lexington, KY 40536 (United States); Hitron, John Andrew [Center for Research on Environmental Disease, University of Kentucky, 1095 VA Drive, Lexington, KY 40536 (United States); Divya, Sasidharan Padmaja; Zhang, Zhuo [Department of Toxicology and Cancer Biology, College of Medicine, University of Kentucky, 1095 VA Drive, Lexington, KY 40536 (United States); Shi, Xianglin, E-mail: xshi5@email.uky.edu [Center for Research on Environmental Disease, University of Kentucky, 1095 VA Drive, Lexington, KY 40536 (United States)

2016-09-15

Hexavalent chromium (Cr(VI)) is classified as a human carcinogen. Cr(VI) has been associated with adenocarcinomas and squamous cell carcinoma of the lung. The present study shows that acute Cr(VI) treatment in human bronchial epithelial cells (BEAS-2B) increased inflammatory responses (TNF-α, COX-2, and NF-кB/p65) and expression of Nrf2. Cr(VI)-induced generation of reactive oxygen species (ROS) are responsible for increased inflammation. Despite the fact that Nrf2 is a master regulator of response to oxidative stress, silencing of Nrf2 in the acute Cr(VI) treatment had no effect on Cr(VI)-induced inflammation. In contrast, in Cr(VI)-transformed (CrT) cells, Nrf2 is constitutively activated. Knock-down of this protein resulted in decreased inflammation, while silencing of SOD2 and CAT had no effect in the expression of these inflammatory proteins. Results obtained from the knock-down of Nrf2 in CrT cells are very different from the results obtained in the acute Cr(VI) treatment. In BEAS-2B cells, knock-down of Nrf2 had no effect in the inflammation levels, while in CrT cells a decrease in the expression of inflammation markers was observed. These results indicate that before transformation, ROS plays a critical role while Nrf2 not in Cr(VI)-induced inflammation, whereas after transformation (CrT cells), Nrf2 is constitutively activated and this protein maintains inflammation while ROS not. Constitutively high levels of Nrf2 in CrT binds to the promoter regions of COX-2 and TNF-α, leading to increased inflammation. Collectively, our results demonstrate that before cell transformation ROS are important in Cr(VI)-induced inflammation and after transformation a constitutively high level of Nrf2 is important. - Highlights: • Cr(VI)-induced ROS increased inflammation, while Nrf2 had no effect. • In the CrT cells knock-down of Nrf2 resulted in decreased inflammation. • Mechanistic differences in regulating Cr(VI)-induced inflammation.

Kinetic investigations of quinoline oxidation by ferrate(VI).

Science.gov (United States)

Luo, Zhiyong; Li, Xueming; Zhai, Jun

2016-01-01

Quinoline is considered as one of the most toxic and carcinogenic compounds and is commonly found in industrial wastewaters, which require treatment before being discharged. Removal of quinoline by the use of an environmentally friendly oxidant, potassium ferrate(VI) (K2FeO4), was assessed by studying the kinetics of the oxidation of quinoline by ferrate(VI) (Fe(VI)) as a function of pH (8.53-10.53) and temperature (21-36°C) in this work. The reaction of quinoline with Fe(VI) was found to be first order in Fe(VI), half order in quinoline, and 1.5 order overall. The observed rate constant at 28°C decreased non-linearly from 0.5334 to 0.2365 M(-0.5) min(-1) with an increase in pH from 8.53 to 10.03. Considering the equilibria of Fe(VI) and quinoline, the reaction between quinoline and Fe(VI) contained two parallel reactions under the given pH conditions. The individual rate constants of these two reactions were determined. The results indicate that the protonated species of Fe(VI) reacts more quickly with quinoline than the deprotonated form of Fe(VI). The reaction activation energy Ea was obtained to be 51.44 kJ·mol(-1), and it was slightly lower than that of conventional chemical reaction. It reveals that the oxidation of quinoline by Fe(VI) is feasible in the routine water treatment.

Immunization with the conjugate vaccine Vi-CRM₁₉₇ against Salmonella typhi induces Vi-specific mucosal and systemic immune responses in mice.

Science.gov (United States)

Fiorino, Fabio; Ciabattini, Annalisa; Rondini, Simona; Pozzi, Gianni; Martin, Laura B; Medaglini, Donata

2012-09-21

Typhoid fever is a public health problem, especially among young children in developing countries. To address this need, a glycoconjugate vaccine Vi-CRM₁₉₇, composed of the polysaccharide antigen Vi covalently conjugated to the non-toxic mutant of diphtheria toxin CRM₁₉₇, is under development. Here, we assessed the antibody and cellular responses, both local and systemic, following subcutaneous injection of Vi-CRM₁₉₇. The glycoconjugate elicited Vi-specific serum IgG titers significantly higher than unconjugated Vi, with prevalence of IgG1 that persisted for at least 60 days after immunization. Vi-specific IgG, but not IgA, were present in intestinal washes. Lymphocytes proliferation after restimulation with Vi-CRM₁₉₇ was observed in spleen and mesenteric lymph nodes. These data confirm the immunogenicity of Vi-CRM₁₉₇ and demonstrate that the vaccine-specific antibody and cellular immune responses are present also in the intestinal tract, thus strengthening the suitability of Vi-CRM₁₉₇ as a promising candidate vaccine against Salmonella Typhi. Copyright © 2012 Elsevier Ltd. All rights reserved.

Electrochemical alkaline Fe(VI) water purification and remediation.

Science.gov (United States)

Licht, Stuart; Yu, Xingwen

2005-10-15

Fe(VI) is an unusual and strongly oxidizing form of iron, which provides a potentially less hazardous water-purifying agent than chlorine. A novel on-line electrochemical Fe(VI) water purification methodology is introduced. Fe(VI) addition had been a barrier to its effective use in water remediation, because solid Fe(VI) salts require complex (costly) syntheses steps and solutions of Fe(VI) decompose. Online electrochemical Fe(VI) water purification avoids these limitations, in which Fe(VI) is directly prepared in solution from an iron anode as the FeO42- ion, and is added to the contaminant stream. Added FeO42- decomposes, by oxidizing a wide range of water contaminants including sulfides (demonstrated in this study) and other sulfur-containing compounds, cyanides (demonstrated in this study), arsenic (demonstrated in this study), ammonia and other nitrogen-containing compounds (previously demonstrated), a wide range of organics (phenol demonstrated in this study), algae, and viruses (each previously demonstrated).

Electronic structure, fluorescence and photochemistry of the uranyl ion, and comparison with octahedral uranium (VI), ruthenyl (VI), rhenium (V) and osmium (VI) complexes

Energy Technology Data Exchange (ETDEWEB)

Joergensen, C K [Geneva Univ. (Switzerland)

1977-01-01

The highly anisotropic uranyl complexes (with very short U-O distances and very long distances to the ligating atoms in the equatorial plane) are compared with trans-dioxo complexes of 4d/sup 2/Ru(VI) and 5d/sup 2/Re(V) and Os(VI). A major difference is the low-lying empty 5f orbitals, and the first excited state is highly oxidizing, and sufficiently long-lived to abstract hydrogen atoms from most organic molecules. It is argued that even the low concentrations of uranyl carbonate present in sea water is excited by solar radiation roughly every 10 minutes. Octahedral U(VI)O/sub 6/ in perovskites and UF/sub 6/ are also discussed, as well as trans-lawrencium chemistry.

Biosorption of Cr(VI) by coconut coir: Spectroscopic investigation on the reaction mechanism of Cr(VI) with lignocellulosic material

International Nuclear Information System (INIS)

Shen, Ying-Shuian; Wang, Shan-Li; Huang, Shiuh-Tsuen; Tzou, Yu-Min; Huang, Jang-Hung

2010-01-01

In this study, the removal mechanism of Cr(VI) from water by coconut coir (CC) was investigated using X-ray photoelectron spectroscopy (XPS), Cr K-edge X-ray absorption near edge structure (XANES) and FTIR spectroscopy. The results showed that, upon reaction with CC at pH 3, Cr(VI) was reduced to Cr(III), which was either bound to CC or released back into solution. As revealed by the FTIR spectra of CC before and after reacting with Cr(VI), the phenolic methoxyl and hydroxyl groups of lignin in CC are the dominant drivers of Cr(VI) reduction, giving rise to carbonyl and carboxyl groups on CC. These functional groups can subsequently provide binding sites for Cr(III) resulting from Cr(VI) reduction. In conjunction with forming complexes with carbonyl and carboxyl groups, the formation of Cr(III) hydroxide precipitate could also readily occur as revealed by the linear combination fitting of the Cr K-edge XANES spectrum using a set of reference compounds. The phenolic groups in lignin are responsible for initiating Cr(VI) reduction, so lignocellulosic materials containing a higher amount of phenolic groups are expected to be more effective scavengers for removal of Cr(VI) from the environment.

Biosorption of Cr(VI) by coconut coir: Spectroscopic investigation on the reaction mechanism of Cr(VI) with lignocellulosic material

Energy Technology Data Exchange (ETDEWEB)

Shen, Ying-Shuian [Department of Soil and Environmental Sciences, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 40227, Taiwan (China); Wang, Shan-Li, E-mail: slwang@nchu.edu.tw [Department of Soil and Environmental Sciences, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 40227, Taiwan (China); Huang, Shiuh-Tsuen [Department of Soil and Environmental Sciences, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 40227, Taiwan (China); Department of Science Application and Dissemination, National Taichung University, Taichung, Taiwan (China); Tzou, Yu-Min; Huang, Jang-Hung [Department of Soil and Environmental Sciences, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 40227, Taiwan (China)

2010-07-15

In this study, the removal mechanism of Cr(VI) from water by coconut coir (CC) was investigated using X-ray photoelectron spectroscopy (XPS), Cr K-edge X-ray absorption near edge structure (XANES) and FTIR spectroscopy. The results showed that, upon reaction with CC at pH 3, Cr(VI) was reduced to Cr(III), which was either bound to CC or released back into solution. As revealed by the FTIR spectra of CC before and after reacting with Cr(VI), the phenolic methoxyl and hydroxyl groups of lignin in CC are the dominant drivers of Cr(VI) reduction, giving rise to carbonyl and carboxyl groups on CC. These functional groups can subsequently provide binding sites for Cr(III) resulting from Cr(VI) reduction. In conjunction with forming complexes with carbonyl and carboxyl groups, the formation of Cr(III) hydroxide precipitate could also readily occur as revealed by the linear combination fitting of the Cr K-edge XANES spectrum using a set of reference compounds. The phenolic groups in lignin are responsible for initiating Cr(VI) reduction, so lignocellulosic materials containing a higher amount of phenolic groups are expected to be more effective scavengers for removal of Cr(VI) from the environment.

Biosorption of Cr(VI) by coconut coir: spectroscopic investigation on the reaction mechanism of Cr(VI) with lignocellulosic material.

Science.gov (United States)

Shen, Ying-Shuian; Wang, Shan-Li; Huang, Shiuh-Tsuen; Tzou, Yu-Min; Huang, Jang-Hung

2010-07-15

In this study, the removal mechanism of Cr(VI) from water by coconut coir (CC) was investigated using X-ray photoelectron spectroscopy (XPS), Cr K-edge X-ray absorption near edge structure (XANES) and FTIR spectroscopy. The results showed that, upon reaction with CC at pH 3, Cr(VI) was reduced to Cr(III), which was either bound to CC or released back into solution. As revealed by the FTIR spectra of CC before and after reacting with Cr(VI), the phenolic methoxyl and hydroxyl groups of lignin in CC are the dominant drivers of Cr(VI) reduction, giving rise to carbonyl and carboxyl groups on CC. These functional groups can subsequently provide binding sites for Cr(III) resulting from Cr(VI) reduction. In conjunction with forming complexes with carbonyl and carboxyl groups, the formation of Cr(III) hydroxide precipitate could also readily occur as revealed by the linear combination fitting of the Cr K-edge XANES spectrum using a set of reference compounds. The phenolic groups in lignin are responsible for initiating Cr(VI) reduction, so lignocellulosic materials containing a higher amount of phenolic groups are expected to be more effective scavengers for removal of Cr(VI) from the environment. 2010 Elsevier B.V. All rights reserved.

Effects of feedback reliability on feedback-related brain activity: A feedback valuation account.

Science.gov (United States)

Ernst, Benjamin; Steinhauser, Marco

2018-04-06

Adaptive decision making relies on learning from feedback. Because feedback sometimes can be misleading, optimal learning requires that knowledge about the feedback's reliability be utilized to adjust feedback processing. Although previous research has shown that feedback reliability indeed influences feedback processing, the underlying mechanisms through which this is accomplished remain unclear. Here we propose that feedback processing is adjusted by the adaptive, top-down valuation of feedback. We assume that unreliable feedback is devalued relative to reliable feedback, thus reducing the reward prediction errors that underlie feedback-related brain activity and learning. A crucial prediction of this account is that the effects of feedback reliability are susceptible to contrast effects. That is, the effects of feedback reliability should be enhanced when both reliable and unreliable feedback are experienced within the same context, as compared to when only one level of feedback reliability is experienced. To evaluate this prediction, we measured the event-related potentials elicited by feedback in two experiments in which feedback reliability was varied either within or between blocks. We found that the fronto-central valence effect, a correlate of reward prediction errors during reinforcement learning, was reduced for unreliable feedback. But this result was obtained only when feedback reliability was varied within blocks, thus indicating a contrast effect. This suggests that the adaptive valuation of feedback is one mechanism underlying the effects of feedback reliability on feedback processing.

Isolation of a star-shaped uranium(V/VI) cluster from the anaerobic photochemical reduction of uranyl(VI)

International Nuclear Information System (INIS)

Chatelain, Lucile; White, Sarah; Scopelliti, Rosario; Mazzanti, Marinella

2016-01-01

Actinide oxo clusters are an important class of compounds due to their impact on actinide migration in the environment. The photolytic reduction of uranyl(VI) has potential application in catalysis and spent nuclear fuel reprocessing, but the intermediate species involved in this reduction have not yet been elucidated. Here we show that the photolysis of partially hydrated uranyl(VI) in anaerobic conditions leads to the reduction of uranyl(VI), and to the incorporation of the resulting U V species into the stable mixed-valent star-shaped U VI /U V oxo cluster [U(UO 2 ) 5 (μ 3 -O) 5 (PhCOO) 5 (Py) 7 ]. This cluster is only the second example of a U VI /U V cluster and the first one associating uranyl groups to a non-uranyl(V) center. The U V center in 1 is stable, while the reaction of uranyl(V) iodide with potassium benzoate leads to immediate disproportionation and formation of the U 12 IV U 4 V O 24 cluster {[K(Py) 2 ] 2 [K(Py)] 2 [U 16 O 24 (PhCOO) 24 (Py) 2 ]}.

Comparison of U(VI) adsorption onto nanoscale zero-valent iron and red soil in the presence of U(VI)–CO_3/Ca–U(VI)–CO_3 complexes

International Nuclear Information System (INIS)

Zhang, Zhibin; Liu, Jun; Cao, Xiaohong; Luo, Xuanping; Hua, Rong; Liu, Yan; Yu, Xiaofeng; He, Likai

2015-01-01

Highlights: • NZVI can be used for adsorbing U(VI)–CO_3 complexes. • Use of NZVI is feasible for remediation of uranium-contaminated soils. • The mechanism of U(VI)–CO_3 complexes adsorbing onto NZVI has been explained. - Abstract: The influence of U(VI)–CO_3 and Ca–U(VI)–CO_3 complexes on U(VI) adsorption onto red soil and nanoscale zero-valent iron (NZVI) was investigated using batch adsorption and fixed-bed column experiments to simulate the feasibility of NZVI as the reactive medium in permeable- reactive barriers (PRB) for in situ remediation of uranium-contaminated red soils. The adsorption capacity (q_e) and distribution constant (K_d) of NZVI and red soil decreased with increasing pH, dissolved carbonate and calcium concentrations, but the q_e and K_d values of NZVI were 5–10 times higher than those of red soil. The breakthrough pore volume (PV) values increased with the decrease of pH, dissolved carbonate and calcium concentration; however, the breakthrough PV values of the PRB column filled with 5% NZVI were 2.0–3.5 times higher than the 100% red soil column. The U(VI)–CO_3 complexes adsorbed onto the surface of red soil/NZVI (≡SOH) to form SO–UO_2CO_3"− or SO–UO_2 (CO_3)_2"3"−. XPS and XRD analysis further confirmed the reduction of U(VI) to U(IV) and the formation of FeOOH on NZVI surfaces. The findings of this study are significant to the remediation of uranium-contaminated red soils and the consideration of practical U(VI) species in the natural environment.

Audio Feedback to Physiotherapy Students for Viva Voce: How Effective Is "The Living Voice"?

Science.gov (United States)

Munro, Wendy; Hollingworth, Linda

2014-01-01

Assessment and feedback remains one of the categories that students are least satisfied with within the United Kingdom National Student Survey. The Student Charter promotes the use of various formats of feedback to enhance student learning. This study evaluates the use of audio MP3 as an alternative feedback mechanism to written feedback for…

Reactivity of nitrido complexes of ruthenium(VI), osmium(VI), and manganese(V) bearing Schiff base and simple anionic ligands.

Science.gov (United States)

Man, Wai-Lun; Lam, William W Y; Lau, Tai-Chu

2014-02-18

Nitrido complexes (M≡N) may be key intermediates in chemical and biological nitrogen fixation and serve as useful reagents for nitrogenation of organic compounds. Osmium(VI) nitrido complexes bearing 2,2':6',2″-terpyridine (terpy), 2,2'-bipyridine (bpy), or hydrotris(1-pyrazolyl)borate anion (Tp) ligands are highly electrophilic: they can react with a variety of nucleophiles to generate novel osmium(IV)/(V) complexes. This Account describes our recent results studying the reactivity of nitridocomplexes of ruthenium(VI), osmium(VI), and manganese(V) that bear Schiff bases and other simple anionic ligands. We demonstrate that these nitrido complexes exhibit rich chemical reactivity. They react with various nucleophiles, activate C-H bonds, undergo N···N coupling, catalyze the oxidation of organic compounds, and show anticancer activities. Ruthenium(VI) nitrido complexes bearing Schiff base ligands, such as [Ru(VI)(N)(salchda)(CH3OH)](+) (salchda = N,N'-bis(salicylidene)o-cyclohexyldiamine dianion), are highly electrophilic. This complex reacts readily at ambient conditions with a variety of nucleophiles at rates that are much faster than similar reactions using Os(VI)≡N. This complex also carries out unique reactions, including the direct aziridination of alkenes, C-H bond activation of alkanes and C-N bond cleavage of anilines. The addition of ligands such as pyridine can enhance the reactivity of [Ru(VI)(N)(salchda)(CH3OH)](+). Therefore researchers can tune the reactivity of Ru≡N by adding a ligand L trans to nitride: L-Ru≡N. Moreover, the addition of various nucleophiles (Nu) to Ru(VI)≡N initially generate the ruthenium(IV) imido species Ru(IV)-N(Nu), a new class of hydrogen-atom transfer (HAT) reagents. Nucleophiles also readily add to coordinated Schiff base ligands in Os(VI)≡N and Ru(VI)≡N complexes. These additions are often stereospecific, suggesting that the nitrido ligand has a directing effect on the incoming nucleophile. M≡N is also

Addition to the analysis of the Sr VI and Sr VII spectra

International Nuclear Information System (INIS)

Wyart, J.F.

1989-01-01

Fifty-six lines of multicharged strontium are measured with an improved wavelength accuracy, or interpreted for the first time. They are 4p-4s, 4p-5s and 4p-4d transitions in Sr VII and 4p-5s transitions in Sr VI. The revision of the singlet-triplet connection in Sr VII is supported by theoretical survey of the ground configuration in Ge-like ions. (orig.)

Volunteer feedback and perceptions after participation in a phase I, first-in-human Ebola vaccine trial: An anonymous survey.

Directory of Open Access Journals (Sweden)

Julie-Anne Dayer

Full Text Available The continued participation of volunteers in clinical trials is crucial to advances in healthcare. Few data are available regarding the satisfaction and impressions of healthy volunteers after participation in phase I trials, many of which lead to unexpected adverse events. We report feedback from over 100 adult volunteers who took part in a first-in-human trial conducted in a high-income country testing an experimental Ebola vaccine causing significant reactogenicity, as well as unexpected arthritis in one fifth of participants. The anonymous, internet-based satisfaction survey was sent by email to all participants upon their completion of this one-year trial; it asked 24 questions concerning volunteers' motivations, impressions of the trial experience, and overall satisfaction. Answers were summarized using descriptive statistics. Of the 115 trial participants, 103 (90% filled out the survey. Fifty-five respondents (53% were male. Thirty-five respondents (34% were healthcare workers, many of whom would deploy to Ebola-affected countries. All respondents cited scientific advancement as their chief motivation for participation, while 100/103 (97% and 61/103 (59% reported additional "humanitarian reasons" and potential protection from Ebolavirus, respectively. Although investigators had documented adverse events in 97% of trial participants, only 74 of 103 respondents (72% recalled experiencing an adverse event. All reported an overall positive experience, and 93/103 (90% a willingness to participate in future trials. Given the high level of satisfaction, no significant associations could be detected between trial experiences and satisfaction, even among respondents reporting adverse events lasting weeks or months. Despite considerable reactogenicity and unexpected vaccine-related arthritis, all survey respondents reported overall satisfaction. While this trial's context was unique, the positive feedback is likely due at least in part to the

Mechanisms of chromium (VI)-induced apoptosis in anterior pituitary cells.

Science.gov (United States)

Quinteros, Fernanda A; Machiavelli, Leticia I; Miler, Eliana A; Cabilla, Jimena P; Duvilanski, Beatriz H

2008-07-30

Hexavalent chromium (Cr (VI)) is a highly toxic metal. Exposure to Cr (VI) compounds may affect reproductive functions. Due to the importance of anterior pituitary hormones on reproductive physiology we have studied the effects of Cr (VI) on anterior pituitary. We previously demonstrated that, after in vivo Cr (VI) administration, Cr accumulates in the pituitary gland and affects prolactin secretion. In vitro, Cr (VI) causes apoptosis in anterior pituitary cells due to oxidative stress generation. To better understand the mechanisms involved in Cr (VI)-induced apoptosis we studied: (a) whether Cr (VI) affects the intracellular antioxidant response and (b) which of the apoptotic factors participates in Cr (VI) effect. Our results show that Cr (VI) treatment induces a decrease in catalase and glutathione peroxidase (GPx) activity but does not modify glutathione reductase (GR) activity. Cr (VI) exposure causes an increase of GSH levels. p53 and Bax mRNA are also upregulated by the metal. Pifithrin alpha, a p53 transcriptional inhibitor, increases Cr (VI) cytotoxicity, suggesting a role of p53 as a survival molecule. The antioxidant N-acetyl-cysteine (NAC) could prevent Bax mRNA increase and caspase 3 activation, confirming that Cr (VI)-induced apoptosis involves oxidative stress generation.

Multisource feedback to graduate nurses: a multimethod study.

Science.gov (United States)

McPhee, Samantha; Phillips, Nicole M; Ockerby, Cherene; Hutchinson, Alison M

2017-11-01

(1) To explore graduate nurses' perceptions of the influence of multisource feedback on their performance and (2) to explore perceptions of Clinical Nurse Educators involved in providing feedback regarding feasibility and benefit of the approach. Graduate registered nurses are expected to provide high-quality care for patients in demanding and unpredictable clinical environments. Receiving feedback is essential to their development. Performance appraisals are a common method used to provide feedback and typically involve a single source of feedback. Alternatively, multisource feedback allows the learner to gain insight into performance from a variety of perspectives. This study explores multisource feedback in an Australian setting within the graduate nurse context. Multimethod study. Eleven graduates were given structured performance feedback from four raters: Nurse Unit Manager, Clinical Nurse Educator, preceptor and a self-appraisal. Thirteen graduates received standard single-rater appraisals. Data regarding perceptions of feedback for both groups were obtained using a questionnaire. Semistructured interviews were conducted with nurses who received multisource feedback and the educators. In total, 94% (n = 15) of survey respondents perceived feedback was important during the graduate year. Four themes emerged from interviews: informal feedback, appropriateness of raters, elements of delivery and creating an appraisal process that is 'more real'. Multisource feedback was perceived as more beneficial compared to single-rater feedback. Educators saw value in multisource feedback; however, perceived barriers were engaging raters and collating feedback. Some evidence exists to indicate that feedback from multiple sources is valued by graduates. Further research in a larger sample and with more experienced nurses is required. Evidence resulting from this study indicates that multisource feedback is valued by both graduates and educators and informs graduates

Emissions of chromium (VI) from arc welding.

Science.gov (United States)

Heung, William; Yun, Myoung-Jin; Chang, Daniel P Y; Green, Peter G; Halm, Chris

2007-02-01

The presence of Cr in the +6 oxidation state (Cr[VI]) is still observed in ambient air samples in California despite steps taken to reduce emissions from plating operations. One known source of emission of Cr(VI) is welding, especially with high Cr-content materials, such as stainless steels. An experimental effort was undertaken to expand and update Cr(VI) emission factors by conducting tests on four types of arc-welding operations: gas-metal arc welding (GMAW), shielded metal arc welding (SMAW), fluxcore arc welding, and pulsed GMAW. Standard American Welding Society hood results were compared with a total enclosure method that permitted isokinetic sampling for particle size-cut measurement, as well as total collection of the aerosol. The fraction of Cr(VI) emitted per unit mass of Cr electrode consumed was determined. Consistent with AP-42 data, initial results indicate that a significant fraction of the total Cr in the aerosol is in the +6 oxidation state. The fraction of Cr(VI) and total aerosol mass produced by the different arc welding methods varies with the type of welding process used. Self-shielded electrodes that do not use a shield gas, for example, SMAW, produce greater amounts of Cr(VI) per unit mass of electrode consumed. The formation of Cr(VI) from standard electrode wires used for welding mild steel was below the method detection limit after eliminating an artifact in the analytical method used.

Vi-da: vitiligo diagnostic assistance mobile application

Science.gov (United States)

Nugraha, G. A.; Nurhudatiana, A.; Bahana, R.

2018-03-01

Vitiligo is a skin disorder in which white patches of depigmentation appear on different parts of the body. Usually, patients come to hospitals or clinics to have their vitiligo conditions assessed. This can be very tiring to the patients, as vitiligo treatments usually take a relatively long period of time, which can range from months to years. To address this challenge, we present in this paper a prototype of an Android-based mobile application called Vi-DA, which stands for Vitiligo Diagnostic Assistance. Vi-DA consists of three subsystems, which are user sign-up subsystem, camera and image analysis subsystem, and progress report subsystem. The mobile application was developed in Java programming language and uses MySQL as the database system. Vi-DA adopts a vitiligo segmentation algorithm to segment input image into normal skin area, vitiligo skin area, and non-skin area. Results showed that Vi-DA gave comparable results to the previous system implemented in Matlab. User acceptance testing results also showed that all respondents agreed on the usefulness of the system and agreed to use Vi-DA again in the future. Vi-DA benefits both dermatologists and patients as not only a computer-aided diagnosis (CAD) tool but also as a smart application that can be used for self-assessment at home.

ViA: a perceptual visualization assistant

Science.gov (United States)

Healey, Chris G.; St. Amant, Robert; Elhaddad, Mahmoud S.

2000-05-01

This paper describes an automated visualized assistant called ViA. ViA is designed to help users construct perceptually optical visualizations to represent, explore, and analyze large, complex, multidimensional datasets. We have approached this problem by studying what is known about the control of human visual attention. By harnessing the low-level human visual system, we can support our dual goals of rapid and accurate visualization. Perceptual guidelines that we have built using psychophysical experiments form the basis for ViA. ViA uses modified mixed-initiative planning algorithms from artificial intelligence to search of perceptually optical data attribute to visual feature mappings. Our perceptual guidelines are integrated into evaluation engines that provide evaluation weights for a given data-feature mapping, and hints on how that mapping might be improved. ViA begins by asking users a set of simple questions about their dataset and the analysis tasks they want to perform. Answers to these questions are used in combination with the evaluation engines to identify and intelligently pursue promising data-feature mappings. The result is an automatically-generated set of mappings that are perceptually salient, but that also respect the context of the dataset and users' preferences about how they want to visualize their data.

Comparison of U(VI) adsorption onto nanoscale zero-valent iron and red soil in the presence of U(VI)–CO{sub 3}/Ca–U(VI)–CO{sub 3} complexes

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhibin [Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Nanchang 330013 (China); State Key Laboratory Breeding Base of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang 330013 (China); Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Nanchang 330013 (China); Liu, Jun [State Key Laboratory Breeding Base of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang 330013 (China); Cao, Xiaohong, E-mail: xhcao@ecit.cn [Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Nanchang 330013 (China); State Key Laboratory Breeding Base of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang 330013 (China); Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Nanchang 330013 (China); Luo, Xuanping [Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Nanchang 330013 (China); Hua, Rong; Liu, Yan [Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Nanchang 330013 (China); State Key Laboratory Breeding Base of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang 330013 (China); Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Nanchang 330013 (China); Yu, Xiaofeng; He, Likai [Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Nanchang 330013 (China); and others

2015-12-30

Highlights: • NZVI can be used for adsorbing U(VI)–CO{sub 3} complexes. • Use of NZVI is feasible for remediation of uranium-contaminated soils. • The mechanism of U(VI)–CO{sub 3} complexes adsorbing onto NZVI has been explained. - Abstract: The influence of U(VI)–CO{sub 3} and Ca–U(VI)–CO{sub 3} complexes on U(VI) adsorption onto red soil and nanoscale zero-valent iron (NZVI) was investigated using batch adsorption and fixed-bed column experiments to simulate the feasibility of NZVI as the reactive medium in permeable- reactive barriers (PRB) for in situ remediation of uranium-contaminated red soils. The adsorption capacity (q{sub e}) and distribution constant (K{sub d}) of NZVI and red soil decreased with increasing pH, dissolved carbonate and calcium concentrations, but the q{sub e} and K{sub d} values of NZVI were 5–10 times higher than those of red soil. The breakthrough pore volume (PV) values increased with the decrease of pH, dissolved carbonate and calcium concentration; however, the breakthrough PV values of the PRB column filled with 5% NZVI were 2.0–3.5 times higher than the 100% red soil column. The U(VI)–CO{sub 3} complexes adsorbed onto the surface of red soil/NZVI (≡SOH) to form SO–UO{sub 2}CO{sub 3}{sup −} or SO–UO{sub 2} (CO{sub 3}){sub 2}{sup 3−}. XPS and XRD analysis further confirmed the reduction of U(VI) to U(IV) and the formation of FeOOH on NZVI surfaces. The findings of this study are significant to the remediation of uranium-contaminated red soils and the consideration of practical U(VI) species in the natural environment.

Study of new U(VI) and Pu(VI) coprecipitation methods for the preparation of (U,Pu)O2

International Nuclear Information System (INIS)

Sanoit, J. de.

1990-01-01

Two U(VI) and Pu(VI) coprecipitation methods have been studied, for the definition of new processes to prepare (U,Pu)O 2 mixed oxides suitable for making MoX fuels or fast breeder reactor fuels. The first system is based on the coprecipitation of a new U(VI), Pu(VI) compound; ammonium uranoplutonate, where as a second system is related to the precipitation of uranyl plutonyl monocarbonate. Experimental conditions to optimize the precipitation and the filtration steps of these two systems have been determined. After calcination under reducing conditions, the mixed oxides obtained are characterized according to different techniques: granulometry, thermogravimetry, solubility in boiling HNO 3 solutions. The properties of such oxides are excellent. The possible processes for preparing (U, Pu)O 2 using these new routes are compared with those actually exploited [fr

Cr(VI) removal from aqueous solution by dried activated sludge biomass

International Nuclear Information System (INIS)

Wu Jun; Zhang Hua; He Pinjing; Yao Qian; Shao Liming

2010-01-01

Batch experiments were conducted to remove Cr(VI) from aqueous solution using activated sludge biomass. The effects of acid pretreatment of the biomass, initial pH, biomass and Cr(VI) concentrations on Cr(VI) removal efficiency were investigated. Proton consumption during the removal process and the reducing capacity of sludge biomass were studied. The results show that acid pretreatment could significantly improve Cr(VI) removal efficiency and increase Cr(VI) reducing capacity by 20.4%. Cr(VI) removal was remarkably pH-dependent; lower pH (pH = 1, 2) facilitated Cr(VI) reduction while higher pH (pH = 3, 4) favored sorption of the converted Cr(III). Lower Cr(VI) concentration as well as higher biomass concentration could accelerate Cr(VI) removal. Cr(VI) reduction was not the only reason for proton consumption in the removal process. Pseudo-second-order adsorption kinetic model could successfully simulate Cr(VI) removal except under higher pH conditions (pH = 3, 4).

Behaviour of chromium(VI) in stormwater soil infiltration systems

DEFF Research Database (Denmark)

Cederkvist, Karin; Ingvertsen, Simon T.; Jensen, Marina B.

2013-01-01

mm in 2 h) and extreme (100 mm in 3 h) rain events. The objectives were to understand the behaviour of the anionic and toxic Cr(VI) in soil at neutral pH and to asses treatment efficiency towards Cr(VI). During normal rain events Cr(VI) was largely retained (more than 50, even though pH was neutral......The ability of stormwater infiltration systems to retain Cr(VI) was tested by applying a synthetic stormwater runoff solution with a neutral pH and high Cr(VI) concentrations to four intact soil columns excavated from two roadside infiltration swales in Germany. Inlet flow rates mimicked normal (10......, while under extreme rain events approximately 20% of Cr(VI) was retained. In both cases effluent concentrations of Cr(VI) would exceed the threshold value of 3.4 mu g/L if the infiltrated water were introduced to freshwater environments. More knowledge on the composition of the stormwater runoff...

Isolation of a star-shaped uranium(V/VI) cluster from the anaerobic photochemical reduction of uranyl(VI)

Energy Technology Data Exchange (ETDEWEB)

Chatelain, Lucile; White, Sarah; Scopelliti, Rosario; Mazzanti, Marinella [Ecole Polytechnique Federale de Lausanne (EPFL) (Switzerland). Inst. de Sciences et Ingenierie Chimiques

2016-11-07

Actinide oxo clusters are an important class of compounds due to their impact on actinide migration in the environment. The photolytic reduction of uranyl(VI) has potential application in catalysis and spent nuclear fuel reprocessing, but the intermediate species involved in this reduction have not yet been elucidated. Here we show that the photolysis of partially hydrated uranyl(VI) in anaerobic conditions leads to the reduction of uranyl(VI), and to the incorporation of the resulting U{sup V} species into the stable mixed-valent star-shaped U{sup VI}/U{sup V} oxo cluster [U(UO{sub 2}){sub 5}(μ{sub 3}-O){sub 5}(PhCOO){sub 5}(Py){sub 7}]. This cluster is only the second example of a U{sup VI}/U{sup V} cluster and the first one associating uranyl groups to a non-uranyl(V) center. The U{sup V} center in 1 is stable, while the reaction of uranyl(V) iodide with potassium benzoate leads to immediate disproportionation and formation of the U{sub 12}{sup IV}U{sub 4}{sup V}O{sub 24} cluster {[K(Py)_2]_2[K(Py)]_2[U_1_6O_2_4(PhCOO)_2_4(Py)_2]}.

Microbial Precipitation of Cr(III)-Hydroxide and Se(0) Nanoparticles During Anoxic Bioreduction of Cr(VI)- and Se(VI)-Contaminated Water.

Science.gov (United States)

Kim, Yumi; Oh, Jong-Min; Roh, Yul

2017-04-01

This study examined the microbial precipitations of Cr(III)-hydroxide and Se(0) nanoparticles during anoxic bioreductions of Cr(VI) and Se(VI) using metal-reducing bacteria enriched from groundwater. Metal-reducing bacteria enriched from groundwater at the Korea Atomic Energy Research Institute (KAERI) Underground Research Tunnel (KURT), Daejeon, S. Korea were used. Metal reduction and precipitation experiments with the metal-reducing bacteria were conducted using Cr(VI)- and Se(VI)-contaminated water and glucose as a carbon source under an anaerobic environment at room temperature. XRD, SEM-EDX, and TEM-EDX analyses were used to characterize the mineralogy, crystal structure, chemistry, shape, and size distribution of the precipitates. The metal-reducing bacteria reduced Cr(VI) of potassium chromate (K₂CrO₄) to Cr(III) of chromium hydroxide [Cr(OH)3], and Se(VI) of sodium selenate (Na₂SeO₄) to selenium Se(0), with changes of color and turbidity. XRD, SEM-EDX, and TEM-EDX analyses revealed that the chromium hydroxide [Cr(OH)₃] was formed extracellularly with nanoparticles of 20–30 nm in size, and elemental selenium Se(0) nanoparticles had a sphere shape of 50–250 nm in size. These results show that metal-reducing bacteria in groundwater can aid or accelerate precipitation of heavy metals such as Cr(VI) and Se(VI) via bioreduction processes under anoxic environments. These results may also be useful for the recovery of Cr and Se nanoparticles in natural environments.

Nitrate Enhanced Microbial Cr(VI) Reduction-Final Report

Energy Technology Data Exchange (ETDEWEB)

John F. Stolz

2011-06-15

A major challenge for the bioremediation of radionuclides (i.e., uranium, technetium) and metals (i.e., Cr(VI), Hg) is the co-occurrence of nitrate as it can inhibit metal transformation. Denitrification (nitrate reduction to dinitrogen gas) is considered the most important ecological process. For many metal and metalloid reducing bacteria, however, ammonia is the end product through respiratory nitrate reduction (RNRA). The focus of this work was to determine how RNRA impacts Cr(VI) transformation. The goal was to elucidate the specific mechanism(s) that limits Cr(VI) reduction in the presence of nitrate and to use this information to develop strategies that enhance Cr(VI) reduction (and thus detoxification). Our central hypothesis is that nitrate impacts the biotransformation of metals and metalloids in three ways 1) as a competitive alternative electron acceptor (inhibiting transformation), 2) as a co-metabolite (i.e., concomitant reduction, stimulating transformation), and 3) as an inducer of specific proteins and pathways involved in oxidation/reduction reactions (stimulating transformation). We have identified three model organisms, Geobacter metallireducens (mechanism 1), Sulfurospirillum barnesii, (mechasism 2), and Desulfovibrio desulfuricans (mechanisms 3). Our specific aims were to 1) investigate the role of Cr(VI) concentration on the kinetics of both growth and reduction of nitrate, nitrite, and Cr(VI) in these three organisms; 2) develop a profile of bacterial enzymes involved in nitrate transformation (e.g., oxidoreductases) using a proteomic approach; 3) investigate the function of periplasmic nitrite reductase (Nrf) as a chromate reductase; and 4) develop a strategy to maximize microbial chromium reduction in the presence of nitrate. We found that growth on nitrate by G. metallireducens was inhibited by Cr(VI). Over 240 proteins were identified by LC/MS-MS. Redox active proteins, outer membrane heavy metal efflux proteins, and chemotaxis sensory

Follower-Centered Perspective on Feedback: Effects of Feedback Seeking on Identification and Feedback Environment

OpenAIRE

Gong, Zhenxing; Li, Miaomiao; Qi, Yaoyuan; Zhang, Na

2017-01-01

In the formation mechanism of the feedback environment, the existing research pays attention to external feedback sources and regards individuals as objects passively accepting feedback. Thus, the external source fails to realize the individuals’ need for feedback, and the feedback environment cannot provide them with useful information, leading to a feedback vacuum. The aim of this study is to examine the effect of feedback-seeking by different strategies on the supervisor-feedback environme...

ACTIVE GALACTIC NUCLEUS FEEDBACK AND ENTROPY INJECTION IN GALAXY CLUSTER CORES

International Nuclear Information System (INIS)

Chaudhuri, Anya; Majumdar, Subhabrata; Nath, Biman B.

2013-01-01

We make the first estimate of non-gravitational energy profiles in galaxy cluster cores (and beyond) based on observational data. Comparing the observed entropy profiles within r 500 , from the Representative XMM-Newton Cluster Structure Survey to simulated base entropy profiles without feedback from both adaptive mesh refinement (AMR) and smoothed particle hydrodynamic (SPH) non-radiative simulations, we estimate the amount of additional non-gravitational energy, E ICM , contained in the intracluster medium (ICM), as well as the total energy feedback, E Feedback , from active galactic nuclei (AGNs; the central AGNs in most cases) into the clusters. The total feedback energy scales with the mean spectroscopic temperature as E Feedback ∝T sp 2.52±0.08 and E Feedback ∝T sp 2.17±0.11 for the SPH and AMR baseline profiles. The mean non-gravitational energy per particle within r 500 remaining in the ICM after energy lost during cooling is ε ICM = 2.8 ± 0.8 keV for the SPH theoretical relation and ε ICM = 1.7 ± 0.9 keV for the AMR theoretical relation. We use the NRAO/VLA Sky Survey source catalog to determine the radio luminosity, L R , at 1.4 GHz of the central source(s) of our sample. For T sp > 3 keV, the E Feedback correlates with L R , although with different normalization for cool-core and non-cool-core clusters. We show that AGNs could provide a significant portion of the feedback

Learning the vi and Vim Editor

CERN Document Server

Robbins, Arnold; Hannah, Elbert

2008-01-01

There's nothing that hard-core Unix and Linux users are more fanatical about than their text editor. Editors are the subject of adoration and worship, or of scorn and ridicule, depending upon whether the topic of discussion is your editor or someone else's. vi has been the standard editor for close to 30 years. Popular on Unix and Linux, it has a growing following on Windows systems, too. Most experienced system administrators cite vi as their tool of choice. And since 1986, this book has been the guide for vi. However, Unix systems are not what they were 30 years ago, and neither is this

Chromium(VI) bioremediation by probiotics.

Science.gov (United States)

Younan, Soraia; Sakita, Gabriel Z; Albuquerque, Talita R; Keller, Rogéria; Bremer-Neto, Hermann

2016-09-01

Chromium is a common mineral in the earth's crust and can be released into the environment from anthropogenic sources. Intake of hexavalent chromium (Cr(VI)) through drinking water and food causes toxic effects, leading to serious diseases, and is a commonly reported environmental problem. Microorganisms can mitigate or prevent the toxic effects caused by heavy metals in addition to having effective resistance mechanisms to prevent cell damage and bind to these metals, sequestering them from the cell surface and removing them from the body. Species of Lactobacillus, Streptococcus, Bacillus and Bifidobacterium present in the human mouth and gut and in fermented foods have the ability to bind and detoxify some of these substances. This review address the primary topics related to Cr(VI) poisoning in animals and humans and the use of probiotics as a way to mitigate or prevent the toxic effects caused by Cr(VI). Further advances in the genetic knowledge of such microorganisms may lead to discoveries which will clarify the most active microorganisms that act as bioprotectants in bodies exposed to Cr(VI) and are an affordable option for people and animals intoxicated by the oral route. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

National Youth Survey US: Wave VI (NYS-1983)

Data.gov (United States)

U.S. Department of Health & Human Services — Youth data for the sixth wave of the National Youth Survey are contained in this collection. This research project, which was designed to gain a better understanding...

GDOT employee survey.

Science.gov (United States)

2017-07-04

The research team worked in collaboration with GDOT to conduct the 2016 GDOT Employee Survey. This research study aimed to increase the response rate and the usefulness of the feedback from the GDOT employee survey to support organizational decisions...

Evaluating a web-based health risk assessment with tailored feedback: what does an expert focus group yield compared to a web-based end-user survey?

Science.gov (United States)

Vosbergen, Sandra; Mahieu, Guy R; Laan, Eva K; Kraaijenhagen, Roderik A; Jaspers, Monique Wm; Peek, Niels

2014-01-02

Increasingly, Web-based health applications are developed for the prevention and management of chronic diseases. However, their reach and utilization is often disappointing. Qualitative evaluations post-implementation can be used to inform the optimization process and ultimately enhance their adoption. In current practice, such evaluations are mainly performed with end-user surveys. However, a review approach by experts in a focus group may be easier to administer and might provide similar results. The aim of this study was to assess whether industrial design engineers in a focus group would address the same issues as end users in a Web-based survey when evaluating a commercial Web-based health risk assessment (HRA) with tailored feedback. Seven Dutch companies used the HRA as part of their corporate health management strategy. Employees using the HRA (N=2289) and 10 independent industrial designers were invited to participate in the study. The HRA consisted of four components: (1) an electronic health questionnaire, (2) biometric measurements, (3) laboratory evaluation, and (4) individually tailored feedback generated by decision support software. After participating in the HRA as end users, both end users and designers evaluated the program. End users completed an evaluation questionnaire that included a free-text field. Designers participated in a focus group discussion. Constructs from user satisfaction and technology acceptance theories were used to categorize and compare the remarks from both evaluations. We assessed and qualitatively analyzed 294 remarks of 189 end users and 337 remarks of 6 industrial designers, pertaining to 295 issues in total. Of those, 137 issues were addressed in the end-user survey and 148 issues in the designer focus group. Only 7.3% (10/137) of the issues addressed in the survey were also addressed in the focus group. End users made more remarks about the usefulness of the HRA and prior expectations that were not met. Designers made

Titanium dioxide-based DGT for measuring dissolved As(V), V(V), Sb(V), Mo(VI) and W(VI) in water

DEFF Research Database (Denmark)

Panther, Jared G.; Stewart, Ryan R.; Teasdale, Peter R.

2013-01-01

A titanium dioxide-based DGT method (Metsorb-DGT) was evaluated for the measurement of As(V), V(V), Sb(V), Mo(VI), W(VI) and dissolved reactive phosphorus (DRP) in synthetic waters. Mass vs. time DGT deployments at pH 6.06 (0.01 mol L-1 NaNO3) demonstrated linear uptake of all analytes (R2...... for deployment times >4 h (CDGT=0.27-0.72). For ferrihydrite-DGT, CDGT/CSol values in the range 0.92-1.16 were obtained for As(V), V(V) and DRP, however, Mo(VI), Sb(V) and W(VI) could not be measured to within 15% of the solution concentration (C DGT/CSol 0.02-0.83)....

ERRORS AND CORRECTIVE FEEDBACK IN WRITING: IMPLICATIONS TO OUR CLASSROOM PRACTICES

Directory of Open Access Journals (Sweden)

Maria Corazon Saturnina A Castro

2017-10-01

Full Text Available Error correction is one of the most contentious and misunderstood issues in both foreign and second language teaching. Despite varying positions on the effectiveness of error correction or the lack of it, corrective feedback remains an institution in the writing classes. Given this context, this action research endeavors to survey prevalent attitudes of teachers and students toward corrective feedback and examine their implications to classroom practices.  This paper poses the major problem:  How do teachers’ perspectives on corrective feedback match the students’ views and expectations about error treatment in their writing? Professors of the University of the Philippines who teach composition classes and over a hundred students enrolled in their classes were surveyed.  Results showed that there are differing perceptions of teachers and students regarding corrective feedback. These oppositions must be addressed as they have implications to current pedagogical practices which include constructing and establishing appropriate lesson goals, using alternative corrective strategies, teaching grammar points in class even in the tertiary level, and further understanding the learning process.

Når vi taler om 68

DEFF Research Database (Denmark)

Jensen, Henrik; Metz, Georg

Når vi taler om 68 er en intellektuel samtale mellem to ligeværdige gentlemen og skallesmækkere. En essayistisk dyst om porno, RAF, Pittelkow og livsfilosofi......Når vi taler om 68 er en intellektuel samtale mellem to ligeværdige gentlemen og skallesmækkere. En essayistisk dyst om porno, RAF, Pittelkow og livsfilosofi...

Research progress in the electrochemical synthesis of ferrate(VI)

International Nuclear Information System (INIS)

Macova, Zuzana; Bouzek, Karel; Hives, Jan; Sharma, Virender K.; Terryn, Raymond J.; Baum, J. Clayton

2009-01-01

There is renewed interest in the +6 oxidation state of iron, ferrate (VI) (Fe VI O 4 2- ), because of its potential as a benign oxidant for organic synthesis, as a chemical in developing cleaner ('greener') technology for remediation processes, and as an alternative for environment-friendly battery cathodes. This interest has led many researchers to focus their attention on the synthesis of ferrate(VI). Of the three synthesis methods, electrochemical, wet chemical and thermal, electrochemical synthesis has received the most attention due to its ease and the high purity of the product. Moreover, electrochemical processes use an electron as a so-called clean chemical, thus avoiding the use of any harmful chemicals to oxidize iron to the +6 oxidation state. This paper reviews the development of electrochemical methods to synthesize ferrate(VI). The approaches chosen by different laboratories to overcome some of the difficulties associated with the electrochemical synthesis of ferrate(VI) are summarized. Special attention is paid to parameters such as temperature, anolyte, and anode material composition. Spectroscopic work to understand the mechanism of ferrate(VI) synthesis is included. Recent advances in two new approaches, the use of an inert electrode and molten hydroxide salts, in the synthesis of ferrate(VI) are also reviewed. Progress made in the commercialization of ferrate(VI) continuous production is briefly discussed as well

Synthesis, characterization and oxidative behaviour of dioxoruthenium(VI) complexes

International Nuclear Information System (INIS)

Agarwal, D.D.; Rastogi, Rachana

1995-01-01

Dioxoruthenium(VI) complexes are found to give low yield of epoxide but good yield of cyclohexanone. The complexes are electro active giving metal centered Ru VI /Ru V couple. Cis-stilbene gives trans epoxide and benzaldehyde. Norbornene gives exo epoxy norbornene. The selectivity for allylic oxidation is high. In the present note the synthesis of dioxoruthenium(VI) complexes and their oxidation behaviour is reported. The dioxoruthenium(VI) complexes have been stoichiometrically found to be good oxidants. (author). 21 refs., 1 tab

Inhibition of bacterial U(VI) reduction by calcium

International Nuclear Information System (INIS)

Brooks, Scott C.; Fredrickson, Jim K.; Carroll, S. L.; Kennedy, David W.; Zachara, John M.; Plymale, Andrew E.; Kelly, S. D.; Kemner, K. M.; Fendorf, S.

2003-01-01

The rapid kinetics of bacterial U(VI) reduction and low solubility of uraninite (UO2,cr) make this process an attractive option for removing uranium from groundwater. Nevertheless, conditions that may promote or inhibit U(VI) reduction are not well-defined. Recent descriptions of Ca-UO2-CO3 complexes indicate that these species may dominate the aqueous speciation of U(VI) in many environments. We monitored the bacterial reduction of U(VI) in bicarbonate-buffered solution in the presence and absence of Ca. XAFS measurements confirmed the presence of a Ca-U(VI)-CO3 complex in the initial solutions containing calcium. Calcium, at millimolar concentrations (0.45-5 mM), caused a significant decrease in the rate and extent of bacterial U(VI) reduction. Both facultative (Shewanella putrefaciens strain CN32) and obligate (Desulfovibrio desulfuricans, Geobacter sulfurreducens) anaerobic bacteria were affected by the presence of calcium. Reduction of U(VI) ceased when the calculated system Eh re ached -0.046+/- 0.001 V, based on the Ca2UO2(CO3)(3) -- > UO2,cr couple. The results are consistent with the hypothesis that U is a less energetically favorable electron acceptor when the Ca-UO2-CO3 complexes are present. The results do not support Ca inhibition caused by direct interactions with the cells or with the electron donor as the reduction of fumarate or Tc(VII)O-4(-) under identical conditions was unaffected by the presence of Ca

Role of combined tactile and kinesthetic feedback in minimally invasive surgery.

Science.gov (United States)

Lim, Soo-Chul; Lee, Hyung-Kew; Park, Joonah

2014-10-18

Haptic feedback is of critical importance in surgical tasks. However, conventional surgical robots do not provide haptic feedback to surgeons during surgery. Thus, in this study, a combined tactile and kinesthetic feedback system was developed to provide haptic feedback to surgeons during robotic surgery. To assess haptic feasibility, the effects of two types of haptic feedback were examined empirically - kinesthetic and tactile feedback - to measure object-pulling force with a telesurgery robotics system at two desired pulling forces (1 N and 2 N). Participants answered a set of questionnaires after experiments. The experimental results reveal reductions in force error (39.1% and 40.9%) when using haptic feedback during 1 N and 2 N pulling tasks. Moreover, survey analyses show the effectiveness of the haptic feedback during teleoperation. The combined tactile and kinesthetic feedback of the master device in robotic surgery improves the surgeon's ability to control the interaction force applied to the tissue. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

New generation ion-imprinted nanocarrier for removal of Cr(VI) from wastewater

International Nuclear Information System (INIS)

Uygun, Murat; Feyzioğlu, Esra; Özçalışkan, Emir; Caka, Müşerref; Ergen, Aygen; Akgöl, Sinan; Denizli, Adil

2013-01-01

The purpose of this study was to prepare a novel ion-imprinted nanoparticle to remove Cr(VI) ions from waste water. For this, Cr(VI) ions were complexed with 2-methacryloylamido histidine (MAH) and then Cr(VI)-imprinted poly(HEMAH) nanoparticles were synthesized by surfactant-free emulsion polymerization technique. The templates, Cr(VI) ions, were removed from the nanoparticles using 0.1 M of HNO 3 solution. The specific surface area of the Cr(VI)-imprinted poly(HEMAH) nanoparticles was found to be 1,397.85 m 2 /g, and the particle size was calculated as 155.3 nm. These Cr(VI)-imprinted nanoparticles were used for the adsorption/desorption of Cr(VI) ions from its aqueous solutions. The effects of initial Cr(VI) concentration and medium pH on the Cr(VI) adsorption capacity were also studied. The maximum adsorbed amount of Cr(VI) on the imprinted nanoparticles was found to be 3,830.58 mg/g nanoparticle in pH 4.0. In order to investigate the selectivity of the imprinted nanoparticle, adsorption studies were repeated using Cr(III) ions. The selectivity results demonstrated that Cr(VI)-imprinted poly(HEMAH) nanoparticles showed high affinity for the Cr(VI) ions than Cr(III). The Cr(VI)-imprinted nanoparticles were used several times without decreasing their Cr(VI) adsorption capacities

New generation ion-imprinted nanocarrier for removal of Cr(VI) from wastewater

Science.gov (United States)

Uygun, Murat; Feyzioğlu, Esra; Özçalışkan, Emir; Caka, Müşerref; Ergen, Aygen; Akgöl, Sinan; Denizli, Adil

2013-08-01

The purpose of this study was to prepare a novel ion-imprinted nanoparticle to remove Cr(VI) ions from waste water. For this, Cr(VI) ions were complexed with 2-methacryloylamido histidine (MAH) and then Cr(VI)-imprinted poly(HEMAH) nanoparticles were synthesized by surfactant-free emulsion polymerization technique. The templates, Cr(VI) ions, were removed from the nanoparticles using 0.1 M of HNO3 solution. The specific surface area of the Cr(VI)-imprinted poly(HEMAH) nanoparticles was found to be 1,397.85 m2/g, and the particle size was calculated as 155.3 nm. These Cr(VI)-imprinted nanoparticles were used for the adsorption/desorption of Cr(VI) ions from its aqueous solutions. The effects of initial Cr(VI) concentration and medium pH on the Cr(VI) adsorption capacity were also studied. The maximum adsorbed amount of Cr(VI) on the imprinted nanoparticles was found to be 3,830.58 mg/g nanoparticle in pH 4.0. In order to investigate the selectivity of the imprinted nanoparticle, adsorption studies were repeated using Cr(III) ions. The selectivity results demonstrated that Cr(VI)-imprinted poly(HEMAH) nanoparticles showed high affinity for the Cr(VI) ions than Cr(III). The Cr(VI)-imprinted nanoparticles were used several times without decreasing their Cr(VI) adsorption capacities.

New generation ion-imprinted nanocarrier for removal of Cr(VI) from wastewater

Energy Technology Data Exchange (ETDEWEB)

Uygun, Murat, E-mail: muygun@adu.edu.tr [Adnan Menderes University, Kocarl Latin-Small-Letter-Dotless-I Vocational and Training School (Turkey); Feyzioglu, Esra; Oezcal Latin-Small-Letter-Dotless-I skan, Emir; Caka, Mueserref; Ergen, Aygen; Akgoel, Sinan [Ege University, Department of Biochemistry, Faculty of Science (Turkey); Denizli, Adil [Hacettepe University, Department of Chemistry, Faculty of Science (Turkey)

2013-08-15

The purpose of this study was to prepare a novel ion-imprinted nanoparticle to remove Cr(VI) ions from waste water. For this, Cr(VI) ions were complexed with 2-methacryloylamido histidine (MAH) and then Cr(VI)-imprinted poly(HEMAH) nanoparticles were synthesized by surfactant-free emulsion polymerization technique. The templates, Cr(VI) ions, were removed from the nanoparticles using 0.1 M of HNO{sub 3} solution. The specific surface area of the Cr(VI)-imprinted poly(HEMAH) nanoparticles was found to be 1,397.85 m{sup 2}/g, and the particle size was calculated as 155.3 nm. These Cr(VI)-imprinted nanoparticles were used for the adsorption/desorption of Cr(VI) ions from its aqueous solutions. The effects of initial Cr(VI) concentration and medium pH on the Cr(VI) adsorption capacity were also studied. The maximum adsorbed amount of Cr(VI) on the imprinted nanoparticles was found to be 3,830.58 mg/g nanoparticle in pH 4.0. In order to investigate the selectivity of the imprinted nanoparticle, adsorption studies were repeated using Cr(III) ions. The selectivity results demonstrated that Cr(VI)-imprinted poly(HEMAH) nanoparticles showed high affinity for the Cr(VI) ions than Cr(III). The Cr(VI)-imprinted nanoparticles were used several times without decreasing their Cr(VI) adsorption capacities.

ALTERATION OF U(VI)-PHASES UNDER OXIDIZING CONDITIONS

Energy Technology Data Exchange (ETDEWEB)

A.P. Deditius; S. Utsunomiya; R.C. Ewing

2006-02-21

Uranium-(VI) phases are the primary alteration products of the UO{sub 2} in spent nuclear fuel and the UO{sub 2+x}, in natural uranium deposits. The U(VI)-phases generally form sheet structures of edge-sharing UO{sub 2}{sup 2+} polyhedra. The complexity of these structures offers numerous possibilities for coupled-substitutions of trace metals and radionuclides. The incorporation of radionuclides into U(VI)-structures provides a potential barrier to their release and transport in a geologic repository that experiences oxidizing conditions. In this study, we have used natural samples of UO{sub 2+x}, to study the U(VI)-phases that form during alteration and to determine the fate of the associated trace elements.

ALTERATION OF U(VI)-PHASES UNDER OXIDIZING CONDITIONS

International Nuclear Information System (INIS)

A.P. Deditius; S. Utsunomiya; R.C. Ewing

2006-01-01

Uranium-(VI) phases are the primary alteration products of the UO 2 in spent nuclear fuel and the UO 2+x , in natural uranium deposits. The U(VI)-phases generally form sheet structures of edge-sharing UO 2 2+ polyhedra. The complexity of these structures offers numerous possibilities for coupled-substitutions of trace metals and radionuclides. The incorporation of radionuclides into U(VI)-structures provides a potential barrier to their release and transport in a geologic repository that experiences oxidizing conditions. In this study, we have used natural samples of UO 2+x , to study the U(VI)-phases that form during alteration and to determine the fate of the associated trace elements

Physician Perceptions of Performance Feedback in a Quality Improvement Activity.

Science.gov (United States)

Eden, Aimee R; Hansen, Elizabeth; Hagen, Michael D; Peterson, Lars E

2017-10-01

Physician performance and peer comparison feedback can affect physician care quality and patient outcomes. This study aimed to understand family physician perspectives of the value of performance feedback in quality improvement (QI) activities. This study analyzed American Board of Family Medicine open-ended survey data collected between 2004 and 2014 from physicians who completed a QI module that provided pre- and post-QI project individual performance data and peer comparisons. Physicians made 3480 comments in response to a question about this performance feedback, which were generally positive in nature (86%). Main themes that emerged were importance of accurate feedback data, enhanced detail in the content of feedback, and ability to customize peer comparison groups to compare performance to peers with similar patient populations or practice characteristics. Meaningful and tailored performance feedback may be an important tool for physicians to improve their care quality and should be considered an integral part of QI project design.

Oxidation of trimethoprim by ferrate(VI): kinetics, products, and antibacterial activity.

Science.gov (United States)

Anquandah, George A K; Sharma, Virender K; Knight, D Andrew; Batchu, Sudha Rani; Gardinali, Piero R

2011-12-15

Kinetics, stoichiometry, and products of the oxidation of trimethoprim (TMP), one of the most commonly detected antibacterial agents in surface waters and municipal wastewaters, by ferrate(VI) (Fe(VI)) were determined. The pH dependent second-order rate constants of the reactions of Fe(VI) with TMP were examined using acid-base properties of Fe(VI) and TMP. The kinetics of reactions of diaminopyrimidine (DAP) and trimethoxytoluene (TMT) with Fe(VI) were also determined to understand the reactivity of Fe(VI) with TMP. Oxidation products of the reactions of Fe(VI) with TMP and DAP were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Reaction pathways of oxidation of TMP by Fe(VI) are proposed to demonstrate the cleavage of the TMP molecule to ultimately result in 3,4,5,-trimethoxybenzaldehyde and 2,4-dinitropyrimidine as among the final identified products. The oxidized products mixture exhibited no antibacterial activity against E. coli after complete consumption of TMP. Removal of TMP in the secondary effluent by Fe(VI) was achieved.

Social Set Visualizer (SoSeVi) II

DEFF Research Database (Denmark)

Flesch, Benjamin; Vatrapu, Ravi

2016-01-01

This paper reports the second iteration of the Social Set Visualizer (SoSeVi), a set theoretical visual analytics dashboard of big social data. In order to further demonstrate its usefulness in large-scale visual analytics tasks of individual and collective behavior of actors in social networks......, the current iteration of the Social Set Visualizer (SoSeVi) in version II builds on recent advancements in visualizing set intersections. The development of the SoSeVi dashboard involved cutting-edge open source visual analytics libraries (D3.js) and creation of new visualizations such as of actor mobility...

Pilot study of a 'RIME'-based tool for giving feedback in a multi-specialty longitudinal clerkship.

Science.gov (United States)

DeWitt, Dawn; Carline, Jan; Paauw, Douglas; Pangaro, Louis

2008-12-01

The Reporter-Interpreter-Manager-Educator (RIME) evaluation framework is intuitive and reliable. Our preceptors' frustration with using summative tools for formative feedback and the hypothesis that the RIME vocabulary might improve students' and preceptors' experiences with feedback prompted us to develop and pilot a RIME-based feedback tool. The tool was based on the RIME vocabulary, which has previously been used for evaluation. As interpersonal skills and professionalism are difficult areas in which to give feedback, we added these as explicit categories. We piloted the tool in a longitudinal, 5-month, multi-specialty clerkship. Preceptors completed pre- and post-introductory workshop surveys. Students completed post-workshop and post-clerkship surveys. Preceptors (n = 14) and students (n = 8) preferred RIME-based feedback to 'usual feedback' (previously given using end-of-clerkship evaluation forms). After the initial workshop, preceptors expected that giving feedback, including critical feedback, would be easier. After the 5-month clerkship, students reported receiving more feedback than in previous clerkships and rated feedback given using this tool more highly (P = 0.002; effect size 1.2). Students also felt it helped them understand specifically how to improve their performance (P = 0.003; effect size 1.2). In this pilot study, preceptors and students preferred feedback with a specific RIME-based tool. Students felt such feedback was more useful and helped them identify specifically how to improve. Whether this method can improve student performance through improved feedback remains an area for further research.

Fremtidens lavenergibyggeri - kan vi gøre som vi plejer?

DEFF Research Database (Denmark)

Larsen, Tine Steen

2011-01-01

Stramninger af kravene til energiforbruget i vores boliger medfører stor fokus på energiberegningen, men erfaringer fra lavenergiboliger opført i dag viser, at vi, for at sikre succes for fremtidens boliger, også skal inddrage dokumentation af indeklimaet og forbedre samarbejdet mellem arkitekter...

Modelling biological Cr(VI) reduction in aquifer microcosm column systems.

Science.gov (United States)

Molokwane, Pulane E; Chirwa, Evans M N

2013-01-01

Several chrome processing facilities in South Africa release hexavalent chromium (Cr(VI)) into groundwater resources. Pump-and-treat remediation processes have been implemented at some of the sites but have not been successful in reducing contamination levels. The current study is aimed at developing an environmentally friendly, cost-effective and self-sustained biological method to curb the spread of chromium at the contaminated sites. An indigenous Cr(VI)-reducing mixed culture of bacteria was demonstrated to reduce high levels of Cr(VI) in laboratory samples. The effect of Cr(VI) on the removal rate was evaluated at concentrations up to 400 mg/L. Following the detailed evaluation of fundamental processes for biological Cr(VI) reduction, a predictive model for Cr(VI) breakthrough through aquifer microcosm reactors was developed. The reaction rate in batch followed non-competitive rate kinetics with a Cr(VI) inhibition threshold concentration of approximately 99 mg/L. This study evaluates the application of the kinetic parameters determined in the batch reactors to the continuous flow process. The model developed from advection-reaction rate kinetics in a porous media fitted best the effluent Cr(VI) concentration. The model was also used to elucidate the logistic nature of biomass growth in the reactor systems.

Diverse functions of myosin VI elucidated by an isoform-specific α-helix domain.

Science.gov (United States)

Wollscheid, Hans-Peter; Biancospino, Matteo; He, Fahu; Magistrati, Elisa; Molteni, Erika; Lupia, Michela; Soffientini, Paolo; Rottner, Klemens; Cavallaro, Ugo; Pozzoli, Uberto; Mapelli, Marina; Walters, Kylie J; Polo, Simona

2016-04-01

Myosin VI functions in endocytosis and cell motility. Alternative splicing of myosin VI mRNA generates two distinct isoform types, myosin VI(short) and myosin VI(long), which differ in the C-terminal region. Their physiological and pathological roles remain unknown. Here we identified an isoform-specific regulatory helix, named the α2-linker, that defines specific conformations and hence determines the target selectivity of human myosin VI. The presence of the α2-linker structurally defines a new clathrin-binding domain that is unique to myosin VI(long) and masks the known RRL interaction motif. This finding is relevant to ovarian cancer, in which alternative myosin VI splicing is aberrantly regulated, and exon skipping dictates cell addiction to myosin VI(short) in tumor-cell migration. The RRL interactor optineurin contributes to this process by selectively binding myosin VI(short). Thus, the α2-linker acts like a molecular switch that assigns myosin VI to distinct endocytic (myosin VI(long)) or migratory (myosin VI(short)) functional roles.

The reduction of Np(VI) and Pu(VI) by organic chelating agents

International Nuclear Information System (INIS)

Reed, D.T.; Aase, S.B.; Banaszak, J.E.

1998-01-01

The reduction of NpO 2+ and PuO 2 2+ by oxalate. citrate, and ethylenediaminetetraacetic acid (EDTA) was investigated in low ionic strength media and brines. This was done to help establish the stability of the An(VI) oxidation state in the presence of organic complexants. The stability of the An(VI) oxidation state depended on the pH and relative strength of the various oxidation state-specific complexes. At low ionic strength and pH 6, NpO 2 O 2+ was rapidly reduced to form NpO 2 + organic complexes. At longer times, Np(IV) organic complexes were observed in the presence of citrate. PuO 2 2+ was predominantly reduced to Pu 4+ , resulting in the formation of organic complexes or polymeric/hydrolytic precipitates. The relative rates of reduction to the An(V) complex were EDTA > citrate > oxalate. Subsequent reduction to An(IV) complexes, however, occurred in the following order: citrate > EDTA > oxalate because of the stability of the An(V)-EDTA complex. The presence of organic complexants led to the rapid reduction of NpO 2 2+ and PuO 2 P 2+ in G-seep brine at pHs 5 and 7. At pHs 8 and 10 in ERDA-6 brine, carbonate and hydrolytic complexes predominated and slowed down or prevented the reduction of An(VI) by the organics present

Interns reflect: the effect of formative assessment with feedback during pre-internship.

Science.gov (United States)

McKenzie, Susan; Burgess, Annette; Mellis, Craig

2017-01-01

It is widely known that the opportunity for medical students to be observed and to receive feedback on their procedural skills performance is variable in the senior years. To address this problem, we provided our Pre-Intern (PrInt) students with "one-to-one" formative feedback on their ability to perform urethral catheterization (U/C) and hypothesized that their future practice of U/C as interns would benefit. This study sought to evaluate the performance and practice of interns in U/C 4-5 months after having received feedback on their performance of U/C as PrInt students. Between 2013 and 2014, two cohorts of interns, (total n=66) who had received recent formative feedback on their U/C performance as PrInt students at Central Clinical School, were invited to complete an anonymous survey. The survey contained nine closed unvalidated questions and one open-ended question, designed to allow interns to report on their current practice of U/C. Forty-one out of 66 interns (62%) completed the survey. Thirty-five out of 41 respondents (85%) reported that the assessment with feedback during their PrInt term was beneficial to their practice. Thirty of 41 (73%) reported being confident to perform U/C independently. Eleven out of 41 respondents (27%) reported that they had received additional training at intern orientation. Nine of the 11 interns (82%) reported that they had a small, but a significant, increase in confidence to perform U/C when compared with the 30 of the 41 respondents (73%) who had not ( p =0.03). Our results substantiate our hypothesis that further education by assessment with feedback in U/C during PrInt was of benefit to interns' performance. Additional educational reinforcement in U/C during intern orientation further improved intern confidence. Our results indicate that extra pre- and post-graduation procedural skills training, with feedback, should be universal.

Contribution to the study of the redox couple Np(VI)/Np(V) in the presence of uranium(VI) in solutions of nitric acid and nitrous acid; Contribution a l'etude du comportement redox du couple Np(VI)/Np(V) en presence d'uranium VI dans les solutions constituees d'acide nitrique et d'acide nitreux

Energy Technology Data Exchange (ETDEWEB)

Arpigny, S. [CEA Marcoule, Dept. de Radiochimie et Procedes, DRP, 30 (France)

2001-07-01

The redox behavior of the Np(VI)/Np(V) couple was the subject of a spectrometric study of the Np(VI) reduction reaction in nitric acid solutions (4 to 5 M) containing variable concentrations (1.5 to 3.5 x 10{sup -3} M) of nitrous acid. A low nitrous acid concentration and a high nitric acid concentration were found to favor the stabilization of Np(VI). The stoichiometric coefficients of nitrous acid and nitric acid in the Np(VI) reduction reaction were determined thermodynamically, although only the reaction order with respect to HNO{sub 2} could be calculated from a kinetic analysis. Adding nitrate ions to a HNO{sub 3}/HNO{sub 2} solution enhanced the stability of neptunium at oxidation state +VI, but also increased the reduction rate. When uranium(VI) was added to the HNO{sub 3}/HNO{sub 2} solutions, the total quantity of neptunium at oxidation state +V (either free or as a Np(V)-U(VI) complex) remained practically unchanged, as did the Np(VI) reduction rate. The electrochemical behavior of the Np(VI)/Np(V) couple was investigated in a weak acidic medium by voltammetry with an ultra-micro-electrode (UME). The oxidation wave limiting current variation was a linear function of the Np(V) concentration when a gold UME was used, but not with a platinum UME; the reduction wave limiting current variation versus the Np(V) concentration was linear with either gold or platinum UMEs. The presence of the Np(V)-U(VI) complex in the neptunium solutions was characterized by a shift in the normal apparent potential of the Np(VI)/Np(V) couple toward anodic potentials consistent with the previously determined values of the complexation constants. (author)

The impact of informational feedback on energy consumption - A survey of the experimental evidence

International Nuclear Information System (INIS)

Faruqui, Ahmad; Sergici, Sanem; Sharif, Ahmed

2010-01-01

In theory, In-Home Displays (IHDs) can revolutionize the way utilities communicate information to customers because they can induce changes in customer behavior even when they are not accompanied by a change in electric prices or rebates for purchasing efficient equipment. IHDs provide consumers with direct feedback - real-time information on energy consumption and costs - and turn a once opaque and static electric bill into a transparent, dynamic, and controllable process. However, to what extent do consumers actually respond to the direct feedback provided by IHDs? In this paper, we seek to empirically answer this question by reviewing a dozen utility pilot programs in North America and abroad that focus on the energy conservation impact of IHDs. We also review overall customer opinions and attitudes towards IHDs and direct feedback to the extent that this information is available from the pilot studies. Our review indicates that the direct feedback provided by IHDs encourages consumers to make more efficient use of energy. We find that consumers who actively use an IHD can reduce their consumption of electricity on average by about 7 percent when prepayment of electricity is not involved. When consumers both use an IHD and are on an electricity prepayment system, they can reduce their electricity consumption by about twice that amount. In regard to demand response impacts, we find that the impact of time-of-use rates is augmented by direct feedback from IHDs. (author)

Vi behøver innovation

DEFF Research Database (Denmark)

McAloone, Tim C.

2007-01-01

-Produktion og Maskiner. Innovation og bæredygtighed er to områder som vi i Skandinavien giver meget stor opmærksomhed for at kunne vedligeholde vores globale konkurrencekraft og stærke velfærdssamfund. Gennem årene har mange brancher bidraget til skabelsen af vidensbaserede innovationer, og det faktum, at de......Analyse: Vi behøver innovation En ny miljøbølge ruller, og danske virksomheder bør ride med Af Tim McAloone, fredag 02. feb 2007 kl. 04:50 Tim McAloone Lektor og ph.d. ved Institut for mekanik, energi og konstruktion ved DTU. Tim McAloone skriver fremover jævnligt kommentarer i Ingeniøren...... skandinaviske lande er relativt små, har ledt til en interessant evne til at etablere og derefter samarbejde inden for tætte netværk, som strækker sig over både faglige og geografiske grænser. Samtidig har vi set miljøhensyn vinde og tabe samfundsmæssig og industriel opmærksomhed på en nærmest periodisk basis...

Thermodynamic analysis of Cr(VI) extraction using TOPO impregnated membranes

Energy Technology Data Exchange (ETDEWEB)

Praveen, Prashant; Loh, Kai-Chee, E-mail: chelohkc@nus.edu.sg

2016-08-15

Highlights: • Cr(VI) extraction by extractant impregnated membranes (EIM) was investigated. • EIM exhibited high extraction efficiency, mass transfer rate and stability. • Mass transfer mechanism was proposed based on kinetics and equilibrium data. • Uptake of Cr(VI) by EIMs was endothermic and spontaneous. • Cr(VI) extraction by EIMs was dominated by physical interactions. - Abstract: Solid/liquid extraction of Cr(VI) was accomplished using trioctylphosphine oxide impregnated polypropylene hollow fiber membranes. Extraction of 100–500 mg/L Cr(VI) by the extractant impregnated membranes (EIM) was characterized by high uptake rate and capacity, and equilibrium was attained within 45 min of contact. Extraction equilibrium was pH-dependent (at an optimal pH 2), whereas stripping using 0.2 M sodium hydroxide yielded the highest recovery of 98% within 60 min. The distribution coefficient was independent of initial Cr(VI) concentration, and the linear distribution equilibrium isotherm could be modeled using Freundlich isotherm. The mass transfer kinetics of Cr(VI) was examined using pseudo-second-order and intraparticle diffusion models and a mass transfer mechanism was deduced. The distribution coefficient increased with temperature, which indicated endothermic nature of the reaction. Enthalpy and entropy change during Cr(VI) extraction were positive and varied in the range of 37–49 kJ/mol and 114–155 J/mol, respectively. The free energy change was negative, confirming the feasibility and spontaneity of the mass transfer process. Results obtained suggest that EIMs are efficient and sustainable for extraction of Cr(VI) from wastewater.

Closing the Loop on Student Feedback: The Case of Australian and Scottish Universities

Science.gov (United States)

Shah, Mahsood; Cheng, Ming; Fitzgerald, Robert

2017-01-01

Universities have a long history of collecting student feedback using surveys and other mechanisms. The last decade has witnessed a significant shift in how student feedback is systematically collected, analysed, reported, and used by governments and institutions. This shift is due to a number of factors, including changes in government policy…

Interns reflect: the effect of formative assessment with feedback during pre-internship

Directory of Open Access Journals (Sweden)

McKenzie S

2017-01-01

Full Text Available Susan McKenzie,1 Annette Burgess,2 Craig Mellis1 1Central Clinical School, 2Education Office, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia Background: It is widely known that the opportunity for medical students to be observed and to receive feedback on their procedural skills performance is variable in the senior years. To address this problem, we provided our Pre-Intern (PrInt students with “one-to-one” formative feedback on their ability to perform urethral catheterization (U/C and hypothesized that their future practice of U/C as interns would benefit. This study sought to evaluate the performance and practice of interns in U/C 4–5 months after having received feedback on their performance of U/C as PrInt students.Methods: Between 2013 and 2014, two cohorts of interns, (total n=66 who had received recent formative feedback on their U/C performance as PrInt students at Central Clinical School, were invited to complete an anonymous survey. The survey contained nine closed unvalidated questions and one open-ended question, designed to allow interns to report on their current practice of U/C.Results: Forty-one out of 66 interns (62% completed the survey. Thirty-five out of 41 respondents (85% reported that the assessment with feedback during their PrInt term was beneficial to their practice. Thirty of 41 (73% reported being confident to perform U/C independently. Eleven out of 41 respondents (27% reported that they had received additional training at intern orientation. Nine of the 11 interns (82% reported that they had a small, but a significant, increase in confidence to perform U/C when compared with the 30 of the 41 respondents (73% who had not (p=0.03.Conclusion: Our results substantiate our hypothesis that further education by assessment with feedback in U/C during PrInt was of benefit to interns’ performance. Additional educational reinforcement in U/C during intern orientation further improved intern

A better understanding of ambulance personnel's attitude towards real-time resuscitation feedback.

Science.gov (United States)

Brinkrolf, Peter; Lukas, Roman; Harding, Ulf; Thies, Sebastian; Gerss, Joachim; Van Aken, Hugo; Lemke, Hans; Schniedermeier, Udo; Bohn, Andreas

2018-03-01

High-quality chest compressions during cardiopulmonary resuscitation (CPR) play a significant role in surviving cardiac arrest. Chest-compression quality can be measured and corrected by real-time CPR feedback devices, which are not yet commonly used. This article looks at the acceptance of such systems in comparison of equipped and unequipped personnel. Two groups of emergency medical services' (EMS) personnel were interviewed using standardized questionnaires. The survey was conducted in the German cities Dortmund and Münster. Overall, 205 persons participated in the survey: 103 paramedics and emergency physicians from the Dortmund fire service and 102 personnel from the Münster service. The staff of the Dortmund service were not equipped with real-time feedback systems. The test group of equipped personnel of the ambulance service of Münster Fire brigade uses real-time feedback systems since 2007. What is the acceptance level of real-time feedback systems? Are there differences between equipped and unequipped personnel? The total sample is receptive towards real-time feedback systems. More than 80% deem the system useful. However, this study revealed concerns and prejudices by unequipped personnel. Negative ratings are significantly lower at the Münster site that is experienced with the use of the real-time feedback system in contrast to the Dortmund site where no such experience exists-the system's use in daily routine results in better evaluation than the expectations of unequipped personnel. Real-time feedback systems receive overall positive ratings. Prejudices and concerns seem to decrease with continued use of the system.

Feedback Valence Affects Auditory Perceptual Learning Independently of Feedback Probability

Science.gov (United States)

Amitay, Sygal; Moore, David R.; Molloy, Katharine; Halliday, Lorna F.

2015-01-01

Previous studies have suggested that negative feedback is more effective in driving learning than positive feedback. We investigated the effect on learning of providing varying amounts of negative and positive feedback while listeners attempted to discriminate between three identical tones; an impossible task that nevertheless produces robust learning. Four feedback conditions were compared during training: 90% positive feedback or 10% negative feedback informed the participants that they were doing equally well, while 10% positive or 90% negative feedback informed them they were doing equally badly. In all conditions the feedback was random in relation to the listeners’ responses (because the task was to discriminate three identical tones), yet both the valence (negative vs. positive) and the probability of feedback (10% vs. 90%) affected learning. Feedback that informed listeners they were doing badly resulted in better post-training performance than feedback that informed them they were doing well, independent of valence. In addition, positive feedback during training resulted in better post-training performance than negative feedback, but only positive feedback indicating listeners were doing badly on the task resulted in learning. As we have previously speculated, feedback that better reflected the difficulty of the task was more effective in driving learning than feedback that suggested performance was better than it should have been given perceived task difficulty. But contrary to expectations, positive feedback was more effective than negative feedback in driving learning. Feedback thus had two separable effects on learning: feedback valence affected motivation on a subjectively difficult task, and learning occurred only when feedback probability reflected the subjective difficulty. To optimize learning, training programs need to take into consideration both feedback valence and probability. PMID:25946173

Influence of Calcium on Microbial Reduction of Solid Phase Uranium (VI)

International Nuclear Information System (INIS)

Liu, Chongxuan; Jeon, Byong-Hun; Zachara, John M.; Wang, Zheming

2007-01-01

The effect of calcium on microbial reduction of a solid phase U(VI), sodium boltwoodite (NaUO2SiO3OH · 1.5H2O), was evaluated in a culture of a dissimilatory metal-reducing bacterium (DMRB), Shewanella oneidensis strain MR-1. Batch experiments were performed in a non-growth bicarbonate medium with lactate as electron donor at pH 7 buffered with PIPES. Calcium increased both the rate and extent of Na-boltwoodite dissolution by increasing its solubility through the formation of a ternary aqueous calcium-uranyl-carbonate species. The ternary species, however, decreased the rates of microbial reduction of aqueous U(VI). Laser-induced fluorescence spectroscopy (LIFS) and transmission electron microscopy (TEM) revealed that microbial reduction of solid phase U(VI) is a sequentially coupled process of Na-boltwoodite dissolution, U(VI) aqueous speciation, and microbial reduction of dissolved U(VI) to U(IV) that accumulated on bacterial surfaces/periplasm. The overall rates of microbial reduction of solid phase U(VI) can be described by the coupled rates of dissolution and microbial reduction that were both influenced by calcium. The results demonstrated that dissolved U(VI) concentration during microbial reduction was a complex function of solid phase U(VI) dissolution kinetics, aqueous U(VI) speciation, and microbial activity

A simple Cr(VI)–S(IV)–O{sub 2} system for rapid and simultaneous reduction of Cr(VI) and oxidative degradation of organic pollutants

Energy Technology Data Exchange (ETDEWEB)

Yuan, Yanan; Yang, Shaojie [Department of Environmental Science, Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, 430079 (China); Zhou, Danna, E-mail: zdncug@163.com [Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Wu, Feng [Department of Environmental Science, Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, 430079 (China)

2016-04-15

Highlights: • Rapid and simultaneous reduction of Cr(VI) and degradation of organic pollutants occur. • Oxysulfur radicals generated in Cr(VI)–S(IV)–O{sub 2} system oxidize the organic pollutants. • Acidic pH facilitates the reactions from both directions of reduction and oxidation. • Degradation potential of aromatic amines depends on the substituted groups. • Cr(VI)–S(IV)–O{sub 2} system is promising for “waste control by waste”. - Abstract: Hexavalent chromium (Cr(VI)), a heavy-metal contaminant, can be easily reduced to less toxic trivalent chromium (Cr(III)) by sulfite ions (S(IV)). However, S(IV) has not drawn as much attention as the ferrous ion has. We report herein a novel Cr(VI)–S(IV)–O{sub 2} system containing sulfite ions that rapidly and simultaneously reduces Cr(VI) and oxidize organic pollutants in the presence of oxygen in aqueous solutions. This Cr(VI)–S(IV)-O{sub 2} system contains the initiator Cr(VI), the reductant S(IV), and the oxidant O{sub 2}, which produce oxysulfur radicals (mainly SO{sub 4}·{sup −} and SO{sub 5}·{sup −}) and hydroxyl radicals (OH·). The Cr(VI)/S(IV) molar ratio, pH, and oxygen content play important roles in the entire reaction system. Acidic conditions (pH 3.0) facilitated degradation of organic compounds and reduction of Cr(VI) as well. In addition, experiments of rapid degradation of several kinds of organic pollutants such as azo dye (acid orange 7, AO7), aniline, phenol, bisphenol A etc were also conducted. Preliminary results show that the removal rates of the analogs of phenols or aromatic amines in this Cr(VI)–S(IV)–O{sub 2} system have a relationship with the electronic parameters (Hammett constant, σ) of the substituted groups. Thus, the Cr(VI)–S(IV)–O{sub 2} system, provides an excellent strategy of “waste control by waste” for removing multiple industrial contaminants.

77 FR 64399 - Order of Succession for HUD Region VI

Science.gov (United States)

2012-10-19

... Region VI AGENCY: Office of Field Policy and Management, HUD. ACTION: Notice of Order of Succession... its Field Offices (Region VI). This Order of Succession supersedes all previous Orders of Succession for HUD Region VI. DATES: Effective Date: October 9, 2012. FOR FURTHER INFORMATION CONTACT: Lawrence D...

Extraction behavior of uranium(VI) with polyurethane foam

International Nuclear Information System (INIS)

Tingchia Huang; Donghwang Chen; Muchang Shieh; Chingtsven Huang

1992-01-01

The extraction of uranium(VI) from aqueous solution with polyether-based polyurethane (PU) foam was studied. The effects of the kinds and concentrations of nitrate salts, uranium(VI) concentration, temperature, nitric acid concentration, pH, the content of poly(ethylene oxide) in the polyurethane foam, and the ratio of PU foam weight and solution volume on the extraction of uranium(VI) were investigated. The interferences of fluoride and carbonate ions on the extraction of uranium(VI) were also examined, and methods to overcome both interferences were suggested. It was found that no uranium was extracted in the absence of a nitrate salting-out agent, and the extraction behaviors of uranium(IV) with polyurethane foam could be explained in terms of an etherlike solvent extraction mechanism. In addition, the percentage extraction of a multiple stage was also estimated theoretically

Impact Analysis of Customized Feedback Interventions on Residential Electricity Load Consumption Behavior for Demand Response

Directory of Open Access Journals (Sweden)

Fei Wang

2018-03-01

Full Text Available Considering the limitations of traditional energy-saving policies, a kind of energy conservation method called the Information Feedback to Residential Electricity Load Customers, which could impact the demand response capacity, has increasingly received more attention. However, most of the current feedback programs provide the same feedback information to all customers regardless of their diverse characteristics, which may reduce the energy-saving effects or even backfire. This paper attempts to investigate how different types of customers may change their behaviors under a set of customized feedback. We conducted a field survey study in Qinhuangdao (QHD, China. First, we conducted semi-structured interviews to classify four groups of customers of different energy-saving awareness, energy-saving potential, and behavioral variability. Then, 156 QHD households were surveyed using scenarios to collect feedback of different scenarios. Social science theories were used to guide the discussion on the behavior changes as a result of different feedback strategies and reveal the reasons for customers’ behaviors. Using the Chi-Square test of independence, the variables that have strong correlations with the categories of residents are extracted to provide references for residents’ classification. Finally, the practical implications and needs for future research are discussed.

Vi-CRM 197 as a new conjugate vaccine against Salmonella Typhi.

Science.gov (United States)

Micoli, F; Rondini, S; Pisoni, I; Proietti, D; Berti, F; Costantino, P; Rappuoli, R; Szu, S; Saul, A; Martin, L B

2011-01-17

An efficacious, low cost vaccine against typhoid fever, especially for young children, would make a major impact on disease burden in developing countries. The virulence capsular polysaccharide of Salmonella Typhi (Vi) coupled to recombinant mutant Pseudomonas aeruginosa exoprotein A (Vi-rEPA) has been shown to be highly efficacious. We investigated the use of carrier proteins included in infant vaccines, standardized the conjugation process and developed key assays required for routine lot release at production scale. Vi from a BSL1 organism, Citrobacter freundii, strain WR7011, was used as an alternative to Vi from S. Typhi. We showed that Vi conjugated to CRM(197), a non-toxic mutant of diphtheria toxin, widely used in commercial vaccines, was produced at high yield. Vi-CRM(197) proved immunogenic in animal studies, even without adjuvant. Thus, Vi-CRM(197) appears to be a suitable candidate for the development of a commercially viable, effective typhoid vaccine for developing countries. Copyright © 2010 Elsevier Ltd. All rights reserved.

The adsorption ability of Cr(VI) on sawdust–polyaniline nanocomposite

International Nuclear Information System (INIS)

Binh Phan, Thi; Que Do, Ngoc; Thanh Thuy Mai, Thi

2010-01-01

The results of this study of sawdust–polyaniline nanocomposite synthesized by a chemical method for Cr(VI) treatment in the environment are presented. Cr(VI) adsorption on a composite was determined by colorimetry. The results showed that sawdust–polyaniline composite synthesized with an aniline:sawdust ratio equal to 0.5 had an adsorption degree of 21.4 mg g −1 and adsorbed nearly 99% of the Cr(VI) after 2 h. The composite could be used for the adsorption of Cr(VI) from waste water. The Cr(VI) adsorption ability of the composite slightly depends on the pH value of the medium. The adsorption is fast during the first half hour and then the rate decreases

Testing of ENDF/B-VI data for shielding applications

International Nuclear Information System (INIS)

Ingersoll, D.T.

1995-01-01

Version VI of the U.S. Evaluated Nuclear Data File (END/B-VI) was released for open distribution in 1990 after an extensive multiyear, multilaboratory evaluation effort coordinated by the Cross Section Evaluation Working Group (CSEWG). More than 75 of the 320 evaluations contained in the library are new for Version VI, including many relatively important nuclides and many with substantial changes to the cross-section data. Also, several important changes were made to the basic data formats for Version VI to permit better representation of the data and to allow additional types of data. Although these format changes yielded improved evaluations, they hindered processing of the data for use in applications codes and delayed the timely integral testing of the data. It has been only during the past year that significant integral testing of END/B-VI data has been achieved. The results and conclusions from some of these efforts are summarized in the following paragraphs

Photoreduction of chromium(VI) in the presence of algae, Chlorella vulgaris

International Nuclear Information System (INIS)

Deng Lin; Wang Hongli; Deng Nansheng

2006-01-01

In this thesis, the photochemical reduction of hexavalent chromium Cr(VI) in the presence of algae, Chlorella vulgaris, was investigated under the irradiation of metal halide lamps (λ=365nm, 250W). The affecting factors of photochemical reduction were studied in detail, such as exposure time, initial Cr(VI) concentration, initial algae concentration and pH. The rate of Cr(VI) photochemical reduction increased with algae concentration increasing, exposure time increasing, initial Cr(VI) concentration decreasing and the decrease of pH. When pH increased to 6, the rate of Cr(VI) photochemical reduction nearly vanished. When initial Cr(VI) concentration ranged from 0.4 to 1.0mgL -1 and initial algae concentration ranged from ABS algae (the absorbency of algae)=0.025 to ABS algae =0.180, According to the results of kinetic analyses, the kinetic equation of Cr(VI) photochemical reduction in aqueous solution with algae under 250W metal halide lamps was V 0 =kC 0 0.1718 A algae 0.5235 (C 0 was initial concentration of Cr(VI); A algae was initial concentration of algae) under the condition of pH 4

The National Map Customer Requirements: Findings from Interviews and Surveys

Science.gov (United States)

Sugarbaker, Larry; Coray, Kevin E.; Poore, Barbara

2009-01-01

The purpose of this study was to receive customer feedback and to understand data and information requirements for The National Map. This report provides results and findings from interviews and surveys and will guide policy and operations decisions about data and information requirements leading to the development of a 5-year strategic plan for the National Geospatial Program. These findings are based on feedback from approximately 2,200 customers between February and August 2008. The U.S. Geological Survey (USGS) conducted more than 160 interviews with 200 individuals. The American Society for Photogrammetry and Remote Sensing (ASPRS) and the International Map Trade Association (IMTA) surveyed their memberships and received feedback from over 400 members. The Environmental Systems Research Institute (ESRI) received feedback from over 1,600 of its U.S.-based software users through an online survey sent to customers attending the ESRI International User Conference in the summer of 2008. The results of these surveys were shared with the USGS and have been included in this report.

Learners’ preferences towards Corrective feedback in writing assignments in tertiary education

Directory of Open Access Journals (Sweden)

Horbacauskiene Jolita

2015-12-01

Full Text Available For several decades, there has been a heated debate about the value of providing corrective feedback in writing assignments in English as a foreign language (EFL classes. Despite the fact that corrective feedback in writing has been analysed from various angles, learners’ expectations regarding feedback given by language instructors are still to be considered, especially in different learning settings. Student attitudes have been found to be associated with motivation, proficiency, learner anxiety, autonomous learning, etc. (Elwood & Bode, 2014. Thus, the aim of this paper was to compare EFL learners’ attitudes towards corrective feedback and self-evaluation of writing skills in different learning settings. Students at two technological universities in France and Lithuania were surveyed and asked to complete an anonymous questionnaire combining the Likert scale and rank order questions. The results indicate that frequency of writing assignments seems to have little or no impact on students’ self-evaluation of writing skills. Moreover, although the two groups of students showed preference for feedback on different error types (e.g., feedback on structure vs. feedback on grammar, nevertheless, indirect corrective feedback with a clue was favoured by all the respondents.

A Case for Direct and Indirect Feedback: The Other Side of Coin

Science.gov (United States)

Hashemnezhad, Hossein; Mohammadnejad, Saeed

2012-01-01

The use of WCF is a striking necessity in learning of English as a foreign language. If teachers and students can manipulate well the use of written feedback, both parties will benefit. This research looked at the types of feedback given to EFL students during a 16-week study. For the purpose of the current survey eighty students enrolled freely…

Importance of c-Type cytochromes for U(VI reduction by Geobacter sulfurreducens

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Leang Ching

2007-03-01

Full Text Available Abstract Background In order to study the mechanism of U(VI reduction, the effect of deleting c-type cytochrome genes on the capacity of Geobacter sulfurreducens to reduce U(VI with acetate serving as the electron donor was investigated. Results The ability of several c-type cytochrome deficient mutants to reduce U(VI was lower than that of the wild type strain. Elimination of two confirmed outer membrane cytochromes and two putative outer membrane cytochromes significantly decreased (ca. 50–60% the ability of G. sulfurreducens to reduce U(VI. Involvement in U(VI reduction did not appear to be a general property of outer membrane cytochromes, as elimination of two other confirmed outer membrane cytochromes, OmcB and OmcC, had very little impact on U(VI reduction. Among the periplasmic cytochromes, only MacA, proposed to transfer electrons from the inner membrane to the periplasm, appeared to play a significant role in U(VI reduction. A subpopulation of both wild type and U(VI reduction-impaired cells, 24–30%, accumulated amorphous uranium in the periplasm. Comparison of uranium-accumulating cells demonstrated a similar amount of periplasmic uranium accumulation in U(VI reduction-impaired and wild type G. sulfurreducens. Assessment of the ability of the various suspensions to reduce Fe(III revealed no correlation between the impact of cytochrome deletion on U(VI reduction and reduction of Fe(III hydroxide and chelated Fe(III. Conclusion This study indicates that c-type cytochromes are involved in U(VI reduction by Geobacter sulfurreducens. The data provide new evidence for extracellular uranium reduction by G. sulfurreducens but do not rule out the possibility of periplasmic uranium reduction. Occurrence of U(VI reduction at the cell surface is supported by the significant impact of elimination of outer membrane cytochromes on U(VI reduction and the lack of correlation between periplasmic uranium accumulation and the capacity for uranium

Cr(III) reactivity and foot dermatitis in Cr(VI) positive patients

DEFF Research Database (Denmark)

Hansen, Malene Barré; Menné, Torkil; Johansen, Jeanne Duus

2006-01-01

Chromium allergy has become synonymous with Cr(VI) allergy. However, real exposure to chromium from leather products may include both Cr(III) and Cr(VI). In this study, we investigate the reactivity to both Cr(VI) and Cr(III) in consecutive patients to analyse the relation between foot eczema/leather...... to Cr(III). The increased risk was not due to a higher degree of sensitivity to Cr(VI). Leather was reported most frequently as the suspected cause of chromium dermatitis (54%). However, Cr(VI) allergics having foot eczema and positive or doubtful Cr(III) reactions often had positive reactions to other...

Automatisk formativ feedback kan gi god motivasjon og læring

Directory of Open Access Journals (Sweden)

Bernt Arne Bertheussen

2014-11-01

Full Text Available I artikkelen presenterer vi et konsept der en student løser tradisjonelle finansoppgaver i regneark i stedet for på papir. Oppgavene er interaktive. Dette betyr at studentene kan få formative tilbakemeldinger automatisk når de selv ønsker det. Målet med tilbakemeldingene er å hjelpe studentene til å komme et skritt videre med problemløsingen sin. Den innovative algoritmen som evaluerer studentenes arbeid gir tilbakemeldinger ikke bare på løsningsresultatet, men også på deloppgavene som fører frem til dette. Algoritmen gir tips og kommentarer som studentene kan bruke i arbeidet med å forbedre løsningene sin. En evaluering viser at interaktive oppgaver med formative tilbakemeldinger tilpasset den enkelte engasjerer og motiverer til oppgaveløsing. Studentene opplever også et godt læringsutbytte av å bruke interaktive oppgaver.AbstractThis article presents a concept where business students solve problem-solving tasks using a spreadsheet instead of paper. The tasks are interactive, which means that students can get academic formative feedback on their own request. The feedback focuses both on the process and the final result of the problem-solving. The aim is to guide the student in the right direction. An evaluation reveals that individual formative feedback provided automatically engages students and motivates to problem-solving. The students are also pleased with the learning outcomes from using the digital learning objects.

An experimental study on the sorption of U(VI) onto granite

International Nuclear Information System (INIS)

Baik, Min Hoon; Hahn, Pil Soo

2002-01-01

The sorption of U(VI) on a domestic granite is studied as a function of experimental conditions such as contact time, solution-solid ratio, ionic strength, and pH using a batch procedure. The distribution coefficients, K d 's, of U(VI) are about 1-100mL/g depending on the experimental conditions. The sorption of U(VI) onto granite particles is greatly dependent upon the contact time, solution-solid ratio, and pH, but very little is dependent on the ionic strength. It is noticed that an U(VI)-carbonato ternary surface complex can be formed in the neutral range of pH. In the alkaline range of pH above 7, U(VI) sorption onto granite particles is greatly decreased due to the formation of anionic U(VI)-carbonato aqueous complexes

Simultaneous Cr(VI) bio-reduction and methane production by anaerobic granular sludge.

Science.gov (United States)

Hu, Qian; Sun, Jiaji; Sun, Dezhi; Tian, Lan; Ji, Yanan; Qiu, Bin

2018-08-01

Wastewater containing toxic hexavalent chromium (Cr(VI)) were treated with well-organized anaerobic granular sludge in this study. Results showed that the anaerobic granular sludge rapidly removed Cr(VI), and 2000 µg·L -1 Cr(VI) was completely eliminated within 6 min, which was much faster than the reported duration of removal by reported artificial materials. Sucrose added as a carbon source acted as an initial electron donor to reduce Cr(VI) to Cr(III). This process was considered as the main mechanism of Cr(VI) removal. Methane production by anaerobic granular sludge was improved by the addition of Cr(VI) at a concentration lower than 500 µg·L -1 . Anaerobic granular sludge had a well-organized structure, which presented good resistance against toxic Cr(VI). Trichoccus accelerated the degradation of organic substances to generate acetates with a low Cr(VI) concentration, thereby enhancing methane production by acetotrophic methanogens. Copyright © 2018 Elsevier Ltd. All rights reserved.

Re-examination of immune response and estimation of anti-Vi IgG protective threshold against typhoid fever-based on the efficacy trial of Vi conjugate in young children.

Science.gov (United States)

Szu, Shousun C; Klugman, Keith P; Hunt, Steven

2014-04-25

The capsular polysaccharide of Salmonella enterica serovar Typhi, Vi antigen, is an essential virulence factor and a protective antigen. Similar to other polysaccharide vaccines, the protective action of Vi, both to the polysaccharide alone or when presented as a conjugate, is mediated by serum IgG Vi antibodies. The evaluation of Vi capsular polysaccharide based vaccines to prevent typhoid fever would be significantly facilitated by the identification of a "protective level" of serum antibodies to Vi antigen. The protective level of anti-Vi IgG against typhoid fever was derived from the protective efficacy and immune response of a Vi-rEPA conjugate vaccine efficacy trial. The estimation was derived by two methods: correlation of the percent efficacy and the antibody distribution profile in the vaccine group at a given period of observation, and use of the relative ratio of anti-Vi IgG levels between the vaccine and placebo groups greater or equal to the Relative Risk of typhoid fever used in the efficacy determination. Both methods predicted a similar range of a minimum protective level of anti-Vi IgG between 1.4 and 2.0μg/ml (short term threshold). When applying a protective threshold of 10μg/ml at 6 months post immunization, an IgG level in excess of 1.4μg/ml was achieved by 90% of children at 46 months post immunization, consistent with an 89% level of protection over the duration of the study. We thus suggest that the proportion of children with Vi IgG>10μg/ml (long term threshold) 6 months after immunization may reflect the proportion protected over at least a 4 year period. The current assignment of an anti-Vi IgG protective level may be of value when evaluating vaccine performance of future Vi conjugate vaccines. Published by Elsevier Ltd.

Factors affecting the adsorption of chromium (VI) on activated carbon

Energy Technology Data Exchange (ETDEWEB)

Yavuz, R.; Orbak, I.; Karatepe, N. [Istanbul Technical University, Istanbul (Turkey)

2006-09-15

The aim of this investigation was to determine the adsorption behavior of chromium (VI) on two different activated carbon samples produced from Tuncbilek lignite. The effects of the initial chromium (VI) concentration (250-1000 mg/L), temperature (297-323 K) and pH (2.0-9.5) on adsorption were investigated systematically. The effectiveness of the parameters on chromium adsorption was found to be in the order of pH, the initial Cr(VI) concentration and the temperature. Increasing the pH from 2.0 to 9.5 caused a decrease in adsorption. However, the adsorption was increased by increasing the initial Cr(VI) concentration and temperature. The multilinear mathematical model was also developed to predict the Cr(VI) adsorption on activated carbon samples within the experimental conditions.

Analytical applications of N-phenyl-n-butyro hydroxamic and N-p-tolyl-n-butyro hydroxamic acids towards chromium (VI), copper (II), iron (III) and uranium (VI)

International Nuclear Information System (INIS)

Elkhadir, A. Y. F.

2001-05-01

Two aliphatic hydroxamic acids were prepared; N-phenyl-n-butyro hydroxamic acid and N-p-tolyl-n-butyro hydroxamic acid, by the reaction of β-phenylhydroxylamine and p-tolyl hydroxylamine with n-butyryl chloride. The acids were identified by: their melting points, characteristic reactions with acidic solutions of vanadium (V) and iron (III), infrared spectroscopy, nitrogen content and molecular weight determination. The extractability of these acids towards Cr (VI), Cu (II), Fe (III) and U (VI) were investigated at different pH values and molar acid concentrations. N-phenyl-n- butyro hydroxamic acid has a maximum extraction (98.80%) for Cr (VI) at 4 M H 2 SO 4 , (83.25%) for Cu (II) at pH 6, (99.17%) for Fe (III) at pH 5 and (99.76%) at 4 M HNO 3 for U (VI) respectively. N-p-tolyl-n-butyro hydroxamic acid has a maximum extraction (98.40%) for Cr (VI)at 4 M H 2 SO 4 , (81.30%) for Cu (II) at pH 6, (92.80%) for Fe (III) at pH 5 and (99.64%) for U (VI) at 4 M HNO 3 , respectively. The ratios of the metal to ligands were determined by job method (continuous variation method) and were found to be 1:2 for Cr (VI) and U (VI). (Author)

Analytical applications of N-phenyl-n-butyro hydroxamic and N-p-tolyl-n-butyro hydroxamic acids towards chromium (VI), copper (II), iron (III) and uranium (VI)

Energy Technology Data Exchange (ETDEWEB)

Elkhadir, A Y. F. [Department of Chemistry, Faculty of Science, University of Khartoum, Khartoum (Sudan)

2001-05-01

Two aliphatic hydroxamic acids were prepared; N-phenyl-n-butyro hydroxamic acid and N-p-tolyl-n-butyro hydroxamic acid, by the reaction of {beta}-phenylhydroxylamine and p-tolyl hydroxylamine with n-butyryl chloride. The acids were identified by: their melting points, characteristic reactions with acidic solutions of vanadium (V) and iron (III), infrared spectroscopy, nitrogen content and molecular weight determination. The extractability of these acids towards Cr (VI), Cu (II), Fe (III) and U (VI) were investigated at different pH values and molar acid concentrations. N-phenyl-n- butyro hydroxamic acid has a maximum extraction (98.80%) for Cr (VI) at 4 M H{sub 2}SO{sub 4}, (83.25%) for Cu (II) at pH 6, (99.17%) for Fe (III) at pH 5 and (99.76%) at 4 M HNO{sub 3} for U (VI) respectively. N-p-tolyl-n-butyro hydroxamic acid has a maximum extraction (98.40%) for Cr (VI)at 4 M H{sub 2} SO{sub 4}, (81.30%) for Cu (II) at pH 6, (92.80%) for Fe (III) at pH 5 and (99.64%) for U (VI) at 4 M HNO{sub 3}, respectively. The ratios of the metal to ligands were determined by job method (continuous variation method) and were found to be 1:2 for Cr (VI) and U (VI). (Author)

Photoreduction of chromium(VI) in the presence of algae, Chlorella vulgaris

Energy Technology Data Exchange (ETDEWEB)

Deng Lin [School of Resources and Environmental Science, Wuhan University, Wuhan 430072 (China); Wang Hongli [School of Resources and Environmental Science, Wuhan University, Wuhan 430072 (China); Deng Nansheng [School of Resources and Environmental Science, Wuhan University, Wuhan 430072 (China)]. E-mail: nsdengwhu@163.com

2006-11-16

In this thesis, the photochemical reduction of hexavalent chromium Cr(VI) in the presence of algae, Chlorella vulgaris, was investigated under the irradiation of metal halide lamps ({lambda}=365nm, 250W). The affecting factors of photochemical reduction were studied in detail, such as exposure time, initial Cr(VI) concentration, initial algae concentration and pH. The rate of Cr(VI) photochemical reduction increased with algae concentration increasing, exposure time increasing, initial Cr(VI) concentration decreasing and the decrease of pH. When pH increased to 6, the rate of Cr(VI) photochemical reduction nearly vanished. When initial Cr(VI) concentration ranged from 0.4 to 1.0mgL{sup -1} and initial algae concentration ranged from ABS{sub algae} (the absorbency of algae)=0.025 to ABS{sub algae}=0.180, According to the results of kinetic analyses, the kinetic equation of Cr(VI) photochemical reduction in aqueous solution with algae under 250W metal halide lamps was V{sub 0}=kC{sub 0}{sup 0.1718}A{sub algae}{sup 0.5235} (C{sub 0} was initial concentration of Cr(VI); A{sub algae} was initial concentration of algae) under the condition of pH 4.

Enhancing Healthcare Provider Feedback and Personal Health Literacy

DEFF Research Database (Denmark)

Kaltoft, Mette Kjer; Nielsen, Jesper Bo; Salkeld, Glenn

2015-01-01

In this protocol for a pilot study we seek to establish the feasibility of using a web-based survey to simultaneously supply healthcare organisations and agencies with feedback on a key aspect of the care experience they provide and increase the generic health decision literacy of the individuals...

CoQ10 Deficiency May Indicate Mitochondrial Dysfunction in Cr(VI Toxicity

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Xiali Zhong

2017-04-01

Full Text Available To investigate the toxic mechanism of hexavalent chromium Cr(VI and search for an antidote for Cr(VI-induced cytotoxicity, a study of mitochondrial dysfunction induced by Cr(VI and cell survival by recovering mitochondrial function was performed. In the present study, we found that the gene expression of electron transfer flavoprotein dehydrogenase (ETFDH was strongly downregulated by Cr(VI exposure. The levels of coenzyme 10 (CoQ10 and mitochondrial biogenesis presented by mitochondrial mass and mitochondrial DNA copy number were also significantly reduced after Cr(VI exposure. The subsequent, Cr(VI-induced mitochondrial damage and apoptosis were characterized by reactive oxygen species (ROS accumulation, caspase-3 and caspase-9 activation, decreased superoxide dismutase (SOD and ATP production, increased methane dicarboxylic aldehyde (MDA content, mitochondrial membrane depolarization and mitochondrial permeability transition pore (MPTP opening, increased Ca2+ levels, Cyt c release, decreased Bcl-2 expression, and significantly elevated Bax expression. The Cr(VI-induced deleterious changes were attenuated by pretreatment with CoQ10 in L-02 hepatocytes. These data suggest that Cr(VI induces CoQ10 deficiency in L-02 hepatocytes, indicating that this deficiency may be a biomarker of mitochondrial dysfunction in Cr(VI poisoning and that exogenous administration of CoQ10 may restore mitochondrial function and protect the liver from Cr(VI exposure.

As duas naturezas de Lévi-Strauss

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Philippe Descola

2011-11-01

Full Text Available Aborda-se aqui a complexidade do status do par conceitual natureza e cultura no pensamento de Lévi-Strauss. Ao mesmo tempo ferramenta de análise, cena filosófica dos primórdios e antinomia a superar, revisita-se os diferentes usos e significados na obra de Lévi-Strauss do conceito de natureza e sua relação com o de cultura. Mostra-se como é possível reconhecer na obra de Lévi-Strauss dois conceitos de natureza: por um lado, uma natureza que se opõe à cultura num programa científico formulado em termos classicamente dualistas e, por outro, uma teoria do conhecimento decididamente monista que considera o espírito como parte e produto desse mesmo mundo. Argumenta-se que se o dualismo entre cultura e natureza fundou o pensamento estruturalista de Lévi-Strauss, é na própria obra deste que encontramos os argumentos e meios de superá-lo. A vocação do estruturalismo na antropologia de hoje, no entanto, é de ir mais longe neste caminho do que foi o próprio fundador.

Procedure for plutonium determination using Pu(VI) spectra

International Nuclear Information System (INIS)

Walker, L.F.; Temer, D.J.; Jackson, D.D.

1996-01-01

This document describes a simple spectrophotometric method for determining total plutonium in nitric acid solutions based on the spectrum of Pu(VI). Plutonium samples in nitric acid are oxidized to Pu(VI) with Ce(IV) and the net absorbance at the 830 nm peak is measured

Public Health Climate Change Adaptation Planning Using Stakeholder Feedback.

Science.gov (United States)

Eidson, Millicent; Clancy, Kathleen A; Birkhead, Guthrie S

2016-01-01

Public health climate change adaptation planning is an urgent priority requiring stakeholder feedback. The 10 Essential Public Health Services can be applied to adaptation activities. To develop a state health department climate and health adaptation plan as informed by stakeholder feedback. With Centers for Disease Control and Prevention (CDC) funding, the New York State Department of Health (NYSDOH) implemented a 2010-2013 climate and health planning process, including 7 surveys on perceptions and adaptation priorities. New York State Department of Health program managers participated in initial (n = 41, denominator unknown) and follow-up (72.2%) needs assessments. Surveillance system information was collected from 98.1% of surveillance system managers. For adaptation prioritization surveys, participants included 75.4% of NYSDOH leaders; 60.3% of local health departments (LHDs); and 53.7% of other stakeholders representing environmental, governmental, health, community, policy, academic, and business organizations. Interviews were also completed with 38.9% of other stakeholders. In 2011 surveys, 34.1% of state health program directors believed that climate change would impact their program priorities. However, 84.6% of state health surveillance system managers provided ideas for using databases for climate and health monitoring/surveillance. In 2012 surveys, 46.5% of state health leaders agreed they had sufficient information about climate and health compared to 17.1% of LHDs (P = .0046) and 40.9% of other stakeholders (nonsignificant difference). Significantly fewer (P climate and health into planning compared to state health leaders (55.8%) and other stakeholders (68.2%). Stakeholder groups agreed on the 4 highest priority adaptation categories including core public health activities such as surveillance, coordination/collaboration, education, and policy development. Feedback from diverse stakeholders was utilized by NYSDOH to develop its Climate and Health

78 FR 20119 - Broad Stakeholder Survey

Science.gov (United States)

2013-04-03

... DEPARTMENT OF HOMELAND SECURITY [Docket No. DHS-2012-0042] Broad Stakeholder Survey AGENCY... concerning the Broad Stakeholder Survey. DHS previously published this ICR in the Federal Register on August... across the Nation. The Broad Stakeholder Survey is designed to gather stakeholder feedback on the...

Synthesis of surface Cr (VI)-imprinted magnetic nanoparticles for selective dispersive solid-phase extraction and determination of Cr (VI) in water samples.

Science.gov (United States)

Qi, Xue; Gao, Shuang; Ding, Guosheng; Tang, An-Na

2017-01-01

A facile, rapid and selective magnetic dispersed solid-phase extraction (dSPE) method for the extraction and enrichment of Cr (VI) prior to flame atomic absorption spectrometry (AAS) was introduced. For highly selective and efficient extraction, magnetic Cr (VI)-imprinted nanoparticles (Fe 3 O 4 @ Cr (VI) IIPs) were prepared by hyphenating surface ion-imprinted with sol-gel techniques. In the preparation process, chromate (Cr(VI)) was used as the template ion; vinylimidazole and 3-aminopropyltriethoxysilane were selected as organic functional monomer and co-monomer respectively. Another reagent, methacryloxypropyltrimethoxysilane was adopted as coupling agent to form the stable covalent bonding between organic and inorganic phases. The effects of various parameters on the extraction efficiency, such as pH of sample solution, the amount of adsorbent, extraction time, the type and concentration of eluent were systematically investigated. Furthermore, the thermodynamic and kinetic properties of the adsorption process were studied to explore the internal adsorption mechanism. Under optimized conditions, the preconcentration factor, limit of detection and linear range of the established dSPE-AAS method for Cr (VI) were found to be 98, 0.29μgL -1 and 4-140μgL -1 , respectively. The developed method was also successfully applied to the analysis of Cr (VI) in different water samples with satisfactory results, proving its reliability and feasibility in real sample analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

ICT and Feedback Practices in the Lower-Secondary Foreign Language Classroom

DEFF Research Database (Denmark)

Kjærgaard, Hanne Wacher

2017-01-01

A central part of language teachers’ work consists in providing written corrective feedback for their students using wellknown pen-and-paper practices, and they are often unsure of the return on their investment of time in this task. This article will describe the results of a survey among close ....... The article also presents and discusses some of the advantages that may result from increasing the adequate uses of ICT in this aspect of (foreign) language teaching.......A central part of language teachers’ work consists in providing written corrective feedback for their students using wellknown pen-and-paper practices, and they are often unsure of the return on their investment of time in this task. This article will describe the results of a survey among close...

Patients' use and views of real-time feedback technology in general practice.

Science.gov (United States)

Wright, Christine; Davey, Antoinette; Elmore, Natasha; Carter, Mary; Mounce, Luke; Wilson, Ed; Burt, Jenni; Roland, Martin; Campbell, John

2017-06-01

There is growing interest in real-time feedback (RTF), which involves collecting and summarizing information about patient experience at the point of care with the aim of informing service improvement. To investigate the feasibility and acceptability of RTF in UK general practice. Exploratory randomized trial. Ten general practices in south-west England and Cambridgeshire. All patients attending surgeries were eligible to provide RTF. Touch screens were installed in waiting areas for 12 weeks with practice staff responsible for encouraging patients to provide RTF. All practices received fortnightly feedback summaries. Four teams attended a facilitated reflection session. RTF 'response rates' among consulting patients were estimated, and the representativeness of touch screen users were assessed. The frequency of staff-patient interactions about RTF (direct observation) and patient views of RTF (exit survey) were summarized. Associated costs were collated. About 2.5% consulting patients provided RTF (range 0.7-8.0% across practices), representing a mean of 194 responses per practice. Patients aged above 65 were under-represented among touch screen users. Receptionists rarely encouraged RTF but, when this did occur, 60% patients participated. Patients were largely positive about RTF but identified some barriers. Costs per practice for the twelve-week period ranged from £1125 (unfacilitated team-level feedback) to £1887 (facilitated team ± practitioner-level feedback). The main cost was the provision of touch screens. Response rates for RTF were lower than those of other survey modes, although the numbers of patients providing feedback to each practice were comparable to those achieved in the English national GP patient survey. More patients might engage with RTF if the opportunity were consistently highlighted to them. © 2016 The Authors. Health Expectations Published by John Wiley & Sons Ltd.

Integrating sentiment analysis and term associations with geo-temporal visualizations on customer feedback streams

Science.gov (United States)

Hao, Ming; Rohrdantz, Christian; Janetzko, Halldór; Keim, Daniel; Dayal, Umeshwar; Haug, Lars-Erik; Hsu, Mei-Chun

2012-01-01

Twitter currently receives over 190 million tweets (small text-based Web posts) and manufacturing companies receive over 10 thousand web product surveys a day, in which people share their thoughts regarding a wide range of products and their features. A large number of tweets and customer surveys include opinions about products and services. However, with Twitter being a relatively new phenomenon, these tweets are underutilized as a source for determining customer sentiments. To explore high-volume customer feedback streams, we integrate three time series-based visual analysis techniques: (1) feature-based sentiment analysis that extracts, measures, and maps customer feedback; (2) a novel idea of term associations that identify attributes, verbs, and adjectives frequently occurring together; and (3) new pixel cell-based sentiment calendars, geo-temporal map visualizations and self-organizing maps to identify co-occurring and influential opinions. We have combined these techniques into a well-fitted solution for an effective analysis of large customer feedback streams such as for movie reviews (e.g., Kung-Fu Panda) or web surveys (buyers).

Feedback Conversations: Creating Feedback Dialogues with a New Textual Tool for Industrial Design Student Feedback

Science.gov (United States)

Funk, Mathias; van Diggelen, Migchiel

2017-01-01

In this paper, the authors describe how a study of a large database of written university teacher feedback in the department of Industrial Design led to the development of a new conceptual framework for feedback and the design of a new feedback tool. This paper focuses on the translation of related work in the area of feedback mechanisms for…

Feedback on Feedback: Eliciting Learners' Responses to Written Feedback through Student-Generated Screencasts

Science.gov (United States)

Fernández-Toro, María; Furnborough, Concha

2014-01-01

Despite the potential benefits of assignment feedback, learners often fail to use it effectively. This study examines the ways in which adult distance learners engage with written feedback on one of their assignments. Participants were 10 undergraduates studying Spanish at the Open University, UK. Their responses to feedback were elicited by means…

Modelling Cr(VI) removal by a combined carbon-activated sludge system

International Nuclear Information System (INIS)

Orozco, A. Micaela Ferro; Contreras, Edgardo M.; Zaritzky, Noemi E.

2008-01-01

The combined carbon-activated sludge process has been proposed as an alternative to protect the biomass against toxic substances in wastewaters; however, the information about the effect of powdered-activated carbon (PAC) addition in activated sludge reactors for the treatment of wastewaters containing Cr(VI) is limited. The objectives of the present study were: (a) to evaluate the removal of hexavalent chromium by (i) activated sludge microorganisms in aerobic batch reactors, (ii) powdered-activated carbon, and (iii) the combined action of powdered-activated carbon and biomass; (b) to propose mathematical models that interpret the experimental results. Different Cr(VI) removal systems were tested: (S1) biomass (activated sludge), (S2) PAC, and (S3) the combined activated carbon-biomass system. A Monod-based mathematical model was used to describe the kinetics of Cr(VI) removal in the system S1. A first-order kinetics with respect to Cr(VI) and PAC respectively, was proposed to model the removal of Cr(VI) in the system S2. Cr(VI) removal in the combined carbon-biomass system (S3) was faster than both Cr(VI) removal using PAC or activated sludge individually. Results showed that the removal of Cr(VI) using the activated carbon-biomass system (S3) was adequately described by combining the kinetic equations proposed for the systems S1 and S2

A CMOS rail-to-rail linear VI-converter

NARCIS (Netherlands)

Vervoort, P.P.; Vervoort, P.P.; Wassenaar, R.F.

1995-01-01

A linear CMOS VI-converter operating in strong inversion with a common-mode input range from the negative to the positive supply rail is presented. The circuit consists of three linear VI-converters based on the difference of squares principle. Two of these perform the actual V to I conversion,

Ternary uranium(VI) carbonato humate complex studied by cryo-TRLFS

International Nuclear Information System (INIS)

Steudtner, R.; Sachs, S.; Schmeide, K.; Brendler, V.; Bernhard, G.

2011-01-01

The complex formation of U(VI) with humic acid (HA) in the presence of carbonate was studied by time-resolved laser-induced fluorescence spectroscopy at low temperature (cryo-TRLFS) at pH 8.5. In the presence of HA, a decrease of the luminescence intensity of U(VI) and no shift of the emission band maxima in comparison to the luminescence spectrum of the UO 2 (CO 3 ) 3 4- complex, the dominating U(VI) species under the applied experimental conditions in the absence of HA, was observed. The formation of a ternary U(VI) carbonato humate complex of the type UO 2 (CO 3 ) 2 HA(II) 4- starting from UO 2 (CO 3 ) 3 4- was concluded from the luminescence data. For this complex a complex stability constant of log K=2.83 ± 0.17 was determined. Slope analysis resulted in a slope of 1.12 ± 0.11, which verifies the postulated complexation reaction. The results agree very well with literature data. Speciation calculations show that the formation of the ternary U(VI) carbonato humate complex can significantly influence the U(VI) speciation under environmental conditions. (orig.)

THE SURPRISINGLY CONSTANT STRENGTH OF O VI ABSORBERS OVER COSMIC TIME

International Nuclear Information System (INIS)

Fox, Andrew J.

2011-01-01

O VI absorption is observed in a wide range of astrophysical environments, including the local interstellar medium, the disk and halo of the Milky Way, high-velocity clouds, the Magellanic Clouds, starburst galaxies, the intergalactic medium (IGM), damped Lyα systems, and gamma-ray-burst host galaxies. Here, a new compilation of 775 O VI absorbers drawn from the literature is presented, all observed at high resolution (instrumental FWHM ≤ 20 km s -1 ) and covering the redshift range z = 0-3. In galactic environments [log N(H I) ∼> 20], the mean O VI column density is shown to be insensitive to metallicity, taking a value log N(O VI) ∼ 14.5 for galaxies covering the range -1.6 ∼ 4 K) clouds and hot (∼10 6 K) plasma, although many such layers would have to be intersected by a typical galaxy-halo sight line to build up the characteristic galactic N(O VI). The alternative, widely used model of single-phase photoionization for intergalactic O VI is ruled out by kinematic evidence in the majority of IGM O VI components at low and high redshift.

Reduction of trace quantities of chromium(VI by strong acids

Directory of Open Access Journals (Sweden)

Pezzin Sérgio H

2004-01-01

Full Text Available The chemical behavior of Cr(VI at low concentrations (10-4 to 10-7 mol L-1 in several strong acids was studied using high specific activity 51Cr(VI as a tracer. The speciation of the products from these systems was carried out by ion exchange chromatography with stepwise elution. The results show that trace quantities of Cr(VI, monitored by means of radiochromium (51Cr, are reduced in the presence of mineral acids such as perchloric, hydrochloric, hydrofluoric, sulfuric, nitric and trifluoromethanesulfonic acids, even in the absence of conventional reducing agents, producing different measureable Cr(III species, depending on the acid anion. Detailed studies of the reduction of low concentrations of Cr(VI with nitric acid have shown that the relative rate of reduction increases as the concentration of the acid increases or as the concentration of the Cr(VI decreases.

Estudio de inmunogenicidad de la vacuna antitifoídica cubana de polisacárido Vi vax-TyVi® en ratones

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Juan Carlos Ramírez

2006-08-01

Full Text Available Salmonella enterica serovar Typhi es un microorganismo que provoca más de 16 millones de casos de fiebre tifoidea con aproximadamente 600 000 muertes al año en todo el mundo. Dentro de las vacunas antitifoídicas la de polisacárido capsular Vi ha encontrado, gracias a sus incuestionables ventajas, una gran aceptación entre productores y consumidores. El presente trabajo aborda el estudio de inmunogenicidad de la vacuna antitifoídica cubana de polisacárido Vi vax-TyViâ en ratones. El estudio estuvo conformado por un grupo control no inoculado y un segundo grupo que recibió 0,05 mL de la vacuna por vía intramuscular. Se tomaron muestras de sangre a los -3, 7, 14, 21, 28, 42, 56 y 84 días. La actividad de anticuerpos IgG antipolisacárido Vi de los sueros individuales fue determinada por ELISA. Los datos fueron analizados por grupo y por sexo y se calculó el porcentaje de seroconversión, considerándose respondedor aquel animal que al menos aumentara en cuatro veces su título inicial. La respuesta de anticuerpos inducida por la vacuna mostró un aumento notable de los títulos de IgG antipolisacárido Vi en el grupo vacunado (100% de seroconversión, mientras que el grupo control no incrementó sus niveles mínimos iniciales (0% de respondedores. Aunque más dispersa, la respuesta de anticuerpos antiVi fue significativamente mayor en las hembras que en los machos.

Synthesis, structure and properties of oxo- and dioxochloride complexes of molybdenum(VI) and tungsten(VI) with 8-oxyquinoline

International Nuclear Information System (INIS)

Abramenko, V.L.; Sergienko, V.S.; Egorova, O.A.

2005-01-01

Complexes of oxo- and dioxochlorides of molybdenum(VI) and tungsten(VI) with 8-oxyquinoline of molecular and intracomplex type are synthesized and studied by the method of IR spectroscopy. The complexes have octahedral structure. It is proposed that 8-oxyquinoline in molecular complexes is coordinated by central atom through nitrogen atom of heterocycle, but in intracomplex compounds - through heterocyclic nitrogen atom and oxygen atom of deprotonated OH-group. Thermal stability of the complexes is studied [ru

Quantifying Cr(VI) Production and Export from Serpentine Soil of the California Coast Range.

Science.gov (United States)

McClain, Cynthia N; Fendorf, Scott; Webb, Samuel M; Maher, Kate

2017-01-03

Hexavalent chromium (Cr(VI)) is generated in serpentine soils and exported to surface and groundwaters at levels above health-based drinking water standards. Although Cr(VI) concentrations are elevated in serpentine soil pore water, few studies have reported field evidence documenting Cr(VI) production rates and fluxes that govern Cr(VI) transport from soil to water sources. We report Cr speciation (i) in four serpentine soil depth profiles derived from the California Coast Range serpentinite belt and (ii) in local surface waters. Within soils, we detected Cr(VI) in the same horizons where Cr(III)-minerals are colocated with biogenic Mn(III/IV)-oxides, suggesting Cr(VI) generation through oxidation by Mn-oxides. Water-extractable Cr(VI) concentrations increase with depth constituting a 7.8 to 12 kg/km 2 reservoir of Cr(VI) in soil. Here, Cr(VI) is produced at a rate of 0.3 to 4.8 kg Cr(VI)/km 2 /yr and subsequently flushed from soil during water infiltration, exporting 0.01 to 3.9 kg Cr(VI)/km 2 /yr at concentrations ranging from 25 to 172 μg/L. Although soil-derived Cr(VI) is leached from soil at concentrations exceeding 10 μg/L, due to reduction and dilution during transport to streams, Cr(VI) levels measured in local surface waters largely remain below California's drinking water limit.

Chromium (VI) biosorption properties of multiple resistant bacteria isolated from industrial sewerage.

Science.gov (United States)

Oyetibo, Ganiyu Oladunjoye; Ilori, Matthew Olusoji; Obayori, Oluwafemi Sunday; Amund, Olukayode Oladipo

2013-08-01

Chromium (VI) [Cr (VI)] biosorption by four resistant autochthonous bacterial strains was investigated to determine their potential for use in sustainable marine water-pollution control. Maximum exchange between Cr (VI) ions and protons on the cells surfaces were at 30-35 °C, pH 2.0 and 350-450 mg/L. The bacterial strains effectively removed 79.0-90.5 % Cr (VI) ions from solution. Furthermore, 85.3-93.0 % of Cr (VI) ions were regenerated from the biomasses, and 83.4-91.7 % of the metal was adsorbed when the biomasses was reused. Langmuir isotherm performed better than Freundlich isotherm, depicting that Cr (VI) affinity was in the sequence Rhodococcus sp. AL03Ni > Burkholderia cepacia AL96Co > Corynebacterium kutscheri FL108Hg > Pseudomonas aeruginosa CA207Ni. Biosorption isotherms confirmed that Rhodococcus sp. AL03Ni was a better biosorbent with a maximum uptake of 107.46 mg of Cr (VI) per g (dry weight) of biomass. The results highlight the high potential of the organisms for bacteria-based detoxification of Cr (VI) via biosorption.

Mucopolysaccharidosis VI

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Harmatz Paul

2010-04-01

Full Text Available Abstract Mucopolysaccharidosis VI (MPS VI is a lysosomal storage disease with progressive multisystem involvement, associated with a deficiency of arylsulfatase B leading to the accumulation of dermatan sulfate. Birth prevalence is between 1 in 43,261 and 1 in 1,505,160 live births. The disorder shows a wide spectrum of symptoms from slowly to rapidly progressing forms. The characteristic skeletal dysplasia includes short stature, dysostosis multiplex and degenerative joint disease. Rapidly progressing forms may have onset from birth, elevated urinary glycosaminoglycans (generally >100 μg/mg creatinine, severe dysostosis multiplex, short stature, and death before the 2nd or 3rd decades. A more slowly progressing form has been described as having later onset, mildly elevated glycosaminoglycans (generally ARSB gene, located in chromosome 5 (5q13-5q14. Over 130 ARSB mutations have been reported, causing absent or reduced arylsulfatase B (N-acetylgalactosamine 4-sulfatase activity and interrupted dermatan sulfate and chondroitin sulfate degradation. Diagnosis generally requires evidence of clinical phenotype, arylsulfatase B enzyme activity ®, clinical management was limited to supportive care and hematopoietic stem cell transplantation. Galsulfase is now widely available and is a specific therapy providing improved endurance with an acceptable safety profile. Prognosis is variable depending on the age of onset, rate of disease progression, age at initiation of ERT and on the quality of the medical care provided.

Integrated Cr(VI) removal using constructed wetlands and composting.

Science.gov (United States)

Sultana, Mar-Yam; Chowdhury, Abu Khayer Md Muktadirul Bari; Michailides, Michail K; Akratos, Christos S; Tekerlekopoulou, Athanasia G; Vayenas, Dimitrios V

2015-01-08

The present work was conducted to study integrated chromium removal from aqueous solutions in horizontal subsurface (HSF) constructed wetlands. Two pilot-scale HSF constructed wetlands (CWs) units were built and operated. One unit was planted with common reeds (Phragmites australis) and one was kept unplanted. Influent concentrations of Cr(VI) ranged from 0.5 to 10mg/L. The effect of temperature and hydraulic residence time (8-0.5 days) on Cr(VI) removal were studied. Temperature was proved to affect Cr(VI) removal in both units. In the planted unit maximum Cr(VI) removal efficiencies of 100% were recorded at HRT's of 1 day with Cr(VI) concentrations of 5, 2.5 and 1mg/L, while a significantly lower removal rate was recorded in the unplanted unit. Harvested reed biomass from the CWs was co-composted with olive mill wastes. The final product had excellent physicochemical characteristics (C/N: 14.1-14.7, germination index (GI): 145-157%, Cr: 8-10mg/kg dry mass), fulfills EU requirements and can be used as a fertilizer in organic farming. Copyright © 2014 Elsevier B.V. All rights reserved.

About Politeness, Face, and Feedback: Exploring Resident and Faculty Perceptions of How Institutional Feedback Culture Influences Feedback Practices.

Science.gov (United States)

Ramani, Subha; Könings, Karen D; Mann, Karen V; Pisarski, Emily E; van der Vleuten, Cees P M

2018-03-06

To explore resident and faculty perspectives on what constitutes feedback culture, their perceptions of how institutional feedback culture (including politeness concepts) might influence the quality and impact of feedback, feedback seeking, receptivity, and readiness to engage in bidirectional feedback. Using a constructivist grounded theory approach, five focus group discussions with internal medicine residents, three focus group discussions with general medicine faculty, and eight individual interviews with subspecialist faculty were conducted at Brigham and Women's Hospital between April and December 2016. Discussions and interviews were audiotaped and transcribed verbatim; concurrent data collection and analysis were performed using the constant comparative approach. Analysis was considered through the lens of politeness theory and organizational culture. Twenty-nine residents and twenty-two general medicine faculty participated in focus group discussions, and eight subspecialty faculty participated in interviews. The institutional feedback culture was described by participants as: (1) a culture of politeness, in which language potentially damaging to residents' self-esteem was discouraged, and (2) a culture of excellence, in which the institution's outstanding reputation and pedigree of trainees inhibited constructive feedback. Three key themes situated within this broader cultural context were discovered: normalizing constructive feedback to promote a culture of growth, overcoming the mental block to feedback seeking, and hierarchical culture impeding bidirectional feedback. An institutional feedback culture of excellence and politeness may impede honest, meaningful feedback and may impact feedback seeking, receptivity, and bidirectional feedback exchanges. It is essential to understand the institutional feedback culture before it can be successfully changed.

Retention of U(VI) onto silica in presence of model organic molecules

International Nuclear Information System (INIS)

Pham, T.T.H.; Mercier-Bion, F.; Drot, R.; Lagarde, G.; Simoni, E.; Lambert, J.

2008-01-01

It is well-known that the organic matter influences the retention of ions onto mineral surfaces. However, the major part of concerned studies implies humic substances and complex solids. Another approach for identifying the sorption mechanisms is possible by studying simpler solids than those present in natural medium. So, silica is chosen as mineral surface because of its abundance in soils and of the presence of Si-O groups in clayey minerals. Uranium (VI) is selected as cation. Simple organic molecules like acetic (one carboxylic group) and oxalic (two carboxylic functions) acids are considered as models of the natural organic matter for understanding their role in the retention of U(VI) onto powders and slides of silica. Binary (organics/silica, U(VI)/silica) and ternary systems (organics/silica/U(VI)) are studied by complementary approaches. Sorption edges as function of pH are obtained by liquid scintillation methods and capillary electrophoresis. Different spectroscopic techniques are used to deduce the interactions between the organic matter and U(VI) sorbed onto the silica whose: Time-Resolved Laser induced Fluorescence Spectroscopy (TRLFS), X-ray Photoelectron Spectroscopy (XPS), Nuclear Microprobe Analysis (NMA). The results of the effect of these model organic molecules onto the U(VI) retention showed a good agreement between the different techniques. Concerning the acetic acid, there are not differences in the sorption percentages of uranyl (see the figure). All these results indicate that the uranyl-acetate complexes stay in the aqueous solution rather than sorbing onto the silica. On the contrary, oxalic acid influences the sorption of U(VI) onto the silica surface. The sorption percentage of U(VI) in the ternary system (oxalic acid/silica/U(VI)) is lower than the binary system (U(VI)/silica) (see the figure). So, the presence of oxalic acid decreases the sorption of U(VI) onto the silica surface. (authors)

Experimental Monitoring of Cr(VI) Bio-reduction Using Electrochemical Geophysics

International Nuclear Information System (INIS)

Birsen Canan; Gary R. Olhoeft; William A. Smith

2007-01-01

Many Department of Energy (DOE) sites are contaminated with highly carcinogenic hexavalent chromium (Cr(VI)). In this research, we explore the feasibility of applying complex resistivity to the detection and monitoring of microbially-induced reduction of hexavalent chromium (Cr(VI)) to a less toxic form (Cr(III)). We hope to measure the change in ionic concentration that occurs during this reduction reaction. This form of reduction promises to be an attractive alternative to more expensive remedial treatment methods. The specific goal of this research is to define the minimum and maximum concentration of the chemical and biological compounds in contaminated samples for which the Cr(VI) - Cr(III) reduction processes could be detected via complex resistivity. There are three sets of experiments, each comprised of three sample columns. The first experiment compares three concentrations of Cr(VI) at the same bacterial cell concentration. The second experiment establishes background samples with, and without, Cr(VI) and bacterial cells. The third experiment examines the influence of three different bacterial cell counts on the same concentration of Cr(VI). A polarization relaxation mechanism was observed between 10 and 50 Hz. The polarization mechanism, unfortunately, was not unique to bio-chemically active samples. Spectral analysis of complex resistivity data, however, showed that the frequency where the phase minimum occurred was not constant for bio-chemically active samples throughout the experiment. A significant shifts in phase minima occurred between 10 to 20 Hz from the initiation to completion of Cr(VI) reduction. This phenomena was quantified using the Cole-Cole model and the Marquardt-Levenberg nonlinear least square minimization method. The data suggests that the relaxation time and the time constant of this relaxation are the Cole-Cole parameters most sensitive to changes in biologically-induced reduction of Cr(VI)

Paisaje del viñedo: patrimonio y recurso

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Luis Vicente Elías

2008-01-01

Full Text Available La propuesta de que el paisaje del viñedo sea el complemento a la visita a la bodega, siendo esta el eje del turismo del vino, es el objetivo de este trabajo. Repasando los conceptos variables de patrimonio, llegamos al paisaje del viñedo como recurso, formando parte del patrimonio natural. Pero este no se puede desvincular de los otros aspectos patrimoniales, por lo que la cultura tradicional es el soporte de la tipología de paisaje que queremos proponer y que va contrastar con los nuevos paisajes del viñedo que surgen de las recientes técnicas en los cultivos y de la actual vitivicultura, emparejada con una moderna “cultura del vino”. El análisis de las diversas normativas, que salvaguardan el paisaje y la comprobación del escaso valor legal del paisaje del viñedo, es otro puntal de este trabajo que trata de unir paisaje con cultura tradicional como recursos del Turismo del Vino, integrados en las Rutas del Vino.

How Attributes of the Feedback Message affect Subsequent Feedback Seeking: The interactive effects of feedback sign and type

OpenAIRE

Medvedeff, Megan; Gregory, Jane Brodie; Levy, Paul E

2008-01-01

In the current study, we examined the interactive effects of feedback type and sign on feedback-seeking behaviour, as well as the moderating role of regulatory focus. Using a behavioural measure of feedback seeking, we demonstrated a strong interaction between feedback type and sign, such that individuals subsequently sought the most feedback after they were provided with negative process feedback. Additionally, results suggested that an individual's chronic regulatory focus has implications ...

Delineation and Diagnostic Criteria of Oral-Facial-Digital Syndrome Type VI

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Poretti Andrea

2012-01-01

Full Text Available Abstract Oral-Facial-Digital Syndrome type VI (OFD VI represents a rare phenotypic subtype of Joubert syndrome and related disorders (JSRD. In the original report polydactyly, oral findings, intellectual disability, and absence of the cerebellar vermis at post-mortem characterized the syndrome. Subsequently, the molar tooth sign (MTS has been found in patients with OFD VI, prompting the inclusion of OFD VI in JSRD. We studied the clinical, neurodevelopmental, neuroimaging, and genetic findings in a cohort of 16 patients with OFD VI. We derived the following inclusion criteria from the literature: 1 MTS and one oral finding and polydactyly, or 2 MTS and more than one typical oral finding. The OFD VI neuroimaging pattern was found to be more severe than in other JSRD subgroups and includes severe hypoplasia of the cerebellar vermis, hypoplastic and dysplastic cerebellar hemispheres, marked enlargement of the posterior fossa, increased retrocerebellar collection of cerebrospinal fluid, abnormal brainstem, and frequently supratentorial abnormalities that occasionally include characteristic hypothalamic hamartomas. Additionally, two new JSRD neuroimaging findings (ascending superior cerebellar peduncles and fused thalami have been identified. Tongue hamartomas, additional frenula, upper lip notch, and mesoaxial polydactyly are specific findings in OFD VI, while cleft lip/palate and other types of polydactyly of hands and feet are not specific. Involvement of other organs may include ocular findings, particularly colobomas. The majority of the patients have absent motor development and profound cognitive impairment. In OFD VI, normal cognitive functions are possible, but exceptional. Sequencing of known JSRD genes in most patients failed to detect pathogenetic mutations, therefore the genetic basis of OFD VI remains unknown. Compared with other JSRD subgroups, the neurological findings and impairment of motor development and cognitive functions in OFD

New approach in modeling Cr(VI) sorption onto biomass from metal binary mixtures solutions

Energy Technology Data Exchange (ETDEWEB)

Liu, Chang [College of Environmental Science and Engineering, Anhui Normal University, South Jiuhua Road, 189, 241002 Wuhu (China); Chemical Engineering Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain); Fiol, Núria [Chemical Engineering Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain); Villaescusa, Isabel, E-mail: Isabel.Villaescusa@udg.edu [Chemical Engineering Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain); Poch, Jordi [Applied Mathematics Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain)

2016-01-15

In the last decades Cr(VI) sorption equilibrium and kinetic studies have been carried out using several types of biomasses. However there are few researchers that consider all the simultaneous processes that take place during Cr(VI) sorption (i.e., sorption/reduction of Cr(VI) and simultaneous formation and binding of reduced Cr(III)) when formulating a model that describes the overall sorption process. On the other hand Cr(VI) scarcely exists alone in wastewaters, it is usually found in mixtures with divalent metals. Therefore, the simultaneous removal of Cr(VI) and divalent metals in binary mixtures and the interactive mechanism governing Cr(VI) elimination have gained more and more attention. In the present work, kinetics of Cr(VI) sorption onto exhausted coffee from Cr(VI)–Cu(II) binary mixtures has been studied in a stirred batch reactor. A model including Cr(VI) sorption and reduction, Cr(III) sorption and the effect of the presence of Cu(II) in these processes has been developed and validated. This study constitutes an important advance in modeling Cr(VI) sorption kinetics especially when chromium sorption is in part based on the sorbent capacity of reducing hexavalent chromium and a metal cation is present in the binary mixture. - Highlights: • A kinetic model including Cr(VI) reduction, Cr(VI) and Cr(III) sorption/desorption • Synergistic effect of Cu(II) on Cr(VI) elimination included in the model • Model validation by checking it against independent sets of data.

New approach in modeling Cr(VI) sorption onto biomass from metal binary mixtures solutions

International Nuclear Information System (INIS)

Liu, Chang; Fiol, Núria; Villaescusa, Isabel; Poch, Jordi

2016-01-01

In the last decades Cr(VI) sorption equilibrium and kinetic studies have been carried out using several types of biomasses. However there are few researchers that consider all the simultaneous processes that take place during Cr(VI) sorption (i.e., sorption/reduction of Cr(VI) and simultaneous formation and binding of reduced Cr(III)) when formulating a model that describes the overall sorption process. On the other hand Cr(VI) scarcely exists alone in wastewaters, it is usually found in mixtures with divalent metals. Therefore, the simultaneous removal of Cr(VI) and divalent metals in binary mixtures and the interactive mechanism governing Cr(VI) elimination have gained more and more attention. In the present work, kinetics of Cr(VI) sorption onto exhausted coffee from Cr(VI)–Cu(II) binary mixtures has been studied in a stirred batch reactor. A model including Cr(VI) sorption and reduction, Cr(III) sorption and the effect of the presence of Cu(II) in these processes has been developed and validated. This study constitutes an important advance in modeling Cr(VI) sorption kinetics especially when chromium sorption is in part based on the sorbent capacity of reducing hexavalent chromium and a metal cation is present in the binary mixture. - Highlights: • A kinetic model including Cr(VI) reduction, Cr(VI) and Cr(III) sorption/desorption • Synergistic effect of Cu(II) on Cr(VI) elimination included in the model • Model validation by checking it against independent sets of data

Cr(VI) retention and transport through Fe(III)-coated natural zeolite

Energy Technology Data Exchange (ETDEWEB)

Du, Gaoxiang [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Li, Zhaohui, E-mail: li@uwp.edu [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144 (United States); Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Liao, Libing [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Hanson, Renee; Leick, Samantha; Hoeppner, Nicole [Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144 (United States); Jiang, Wei-Teh [Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

2012-06-30

Graphical abstract: Breakthrough curves of Cr(VI) from columns packed with raw zeolite (a) and Fe(III)-zeolite (b). The solid line in (b) is the HYDRUS-1D fit to the observed data with adsorption term only, while the dashed line in (b) includes a reduction term in the HYDRUS-1D fit. Highlights: Black-Right-Pointing-Pointer Zeolite modified with Fe(III) could be used for adsorption and retention of Cr(VI). Black-Right-Pointing-Pointer The Fe present on zeolite was in an amorphous Fe(OH){sub 3} form. Black-Right-Pointing-Pointer A Cr(VI) adsorption capacity of 82 mg/kg was found on Fe(III)-zeolite. Black-Right-Pointing-Pointer A Cr(VI) retardation factor of 3 or 5 was determined from column and batch studies. - Abstract: Cr(VI) is a group A chemical based on the weight of evidence of carcinogenicity. Its transport and retention in soils and groundwater have been studied extensively. Zeolite is a major component in deposits originated from volcanic ash and tuff after alteration. In this study, zeolite aggregates with the particle size of 1.4-2.4 mm were preloaded with Fe(III). The influence of present Fe(III) on Cr(VI) retention by and transport through zeolite was studied under batch and column experiments. The added Fe(III) resulted in an enhanced Cr(VI) retention by the zeolite with a capacity of 82 mg/kg. The Cr(VI) adsorption on Fe(III)-zeolite followed a pseudo-second order kinetically and the Freundlich adsorption isotherm thermodynamically. Fitting the column experimental data to HYDRUS-1D resulted in a retardation factor of 3 in comparison to 5 calculated from batch tests at an initial Cr(VI) concentration of 3 mg/L. The results from this study showed that enhanced adsorption and retention of Cr(VI) may happen in soils derived from volcanic ash and tuff that contains significant amounts of zeolite with extensive Fe(III) coating.

Simultaneous Treatment of Agro-Industrial and Industrial Wastewaters: Case Studies of Cr(VI/Second Cheese Whey and Cr(VI/Winery Effluents

Directory of Open Access Journals (Sweden)

Triantafyllos I. Tatoulis

2018-03-01

Full Text Available Hexavalent chromium (Cr(VI was co-treated either with second cheese whey (SCW or winery effluents (WE using pilot-scale biological trickling filters in series under different operating conditions. Two pilot-scale filters in series using plastic support media were used in each case. The first filter (i.e., Cr-SCW-filter or Cr-WE-filter aimed at Cr(VI reduction and the partial removal of dissolved chemical oxygen demand (d-COD from SCW or WE and was inoculated with indigenous microorganisms originating from industrial sludge. The second filter in series (i.e., SCW-filter or WE-filter aimed at further d-COD removal and was inoculated with indigenous microorganisms that were isolated from SCW or WE. Various Cr(VI (5–100 mg L−1 and SCW or WE (d-COD, 1000–25,000 mg L−1 feed concentrations were tested. Based on the experimental results, the sequencing batch reactor operating mode with recirculation of 0.5 L min−1 proved very efficient since it led to complete Cr(VI reduction in the first filter in series and achieved high Cr(VI reduction rates (up to 36 and 43 mg L−1 d−1, for SCW and WW, respectively. Percentage d-COD removal for SCW and WE in the first filter was rather low, ranging from 14 to 42.5% and from 4 to 29% in the Cr-SCW-filter and Cr-WE-filter, respectively. However, the addition of the second filter in series enhanced total d-COD removal to above 97% and 90.5% for SCW and WE, respectively. The above results indicate that agro-industrial wastewater could be used as a carbon source for Cr(VI reduction, while the use of two trickling filters in series could effectively treat both industrial and agro-industrial wastewaters with very low installation and operational costs.

Imaging AGN Feedback in NGC 3393 with CHEERS

Science.gov (United States)

Paggi, Alessandro; Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Wang, Junfeng; Storchi-Bergmann, Thaisa

2016-04-01

The CHandra Extended Emission-line Region Survey (CHEERS) is the 'ultimate' resolution X-ray imaging survey of nearby far-IR selected AGN. By comparing deep Chandra observations with complementary HST and radio data, we investigate the morphology of the extended narrow-line region on scales of <100 pc. We present new results on the gas surrounding the compton-thick AGN NGC 3393. The luminous extended narrow-line X-ray emission from this gas allows us to study the role and extent of AGN feedback as sub-kpc jets interact with the surrounding ISM.

Ternary uranium(VI) carbonato humate complex studied by cryo-TRLFS

Energy Technology Data Exchange (ETDEWEB)

Steudtner, R.; Sachs, S.; Schmeide, K.; Brendler, V.; Bernhard, G. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany). Inst. of Radiochemistry

2011-07-01

The complex formation of U(VI) with humic acid (HA) in the presence of carbonate was studied by time-resolved laser-induced fluorescence spectroscopy at low temperature (cryo-TRLFS) at pH 8.5. In the presence of HA, a decrease of the luminescence intensity of U(VI) and no shift of the emission band maxima in comparison to the luminescence spectrum of the UO{sub 2}(CO{sub 3}){sub 3}{sup 4-} complex, the dominating U(VI) species under the applied experimental conditions in the absence of HA, was observed. The formation of a ternary U(VI) carbonato humate complex of the type UO{sub 2}(CO{sub 3}){sub 2}HA(II){sup 4-} starting from UO{sub 2}(CO{sub 3}){sub 3}{sup 4-} was concluded from the luminescence data. For this complex a complex stability constant of log K=2.83 {+-} 0.17 was determined. Slope analysis resulted in a slope of 1.12 {+-} 0.11, which verifies the postulated complexation reaction. The results agree very well with literature data. Speciation calculations show that the formation of the ternary U(VI) carbonato humate complex can significantly influence the U(VI) speciation under environmental conditions. (orig.)

Recovery of uranium (VI) from low level aqueous radioactive waste

International Nuclear Information System (INIS)

Kulshrestha, Mukul

1996-01-01

Investigation was undertaken to evaluate the uranium (VI) removal and recovery potential of a naturally occurring, nonviable macrofungus, Ganoderma Lucidum from the simulated low level aqueous nuclear waste. These low level waste waters discharged from nuclear mine tailings and nuclear power reactors have a typical U(VI) concentration of 10-100 mg/L. It is possible to recover this uranium economically with the advent of biosorption as a viable technology. Extensive laboratory studies have revealed Ganoderma Lucidum to be a potential biosorbent with a specific uptake of 2.75 mg/g at an equilibrium U(VI) concentration of 10 mg/L at pH 4.5. To recover the sorbed U(VI), the studies indicated 0.2N Na 2 CO 3 to be an effective elutant. The kinetics of U(VI) desorption from loaded Ganoderma Lucidum with 0.2N Na 2 CO 3 as elutant, was found to be rapid with more than 75% recovery occurring in the first five minutes, the specific metal release rate being 0.102 mg/g/min. The equilibrium data fitted to a linearised Freundlich plot and exhibited a near 100% recovery of sorbed U(VI), clearly revealing a cost-effective method of recovery of precious uranium from low level wastewater. (author). 7 refs., 3 figs., 1 tab

Solvent impregnated resin for isolation of U(VI) from industrial wastes

International Nuclear Information System (INIS)

Karve, M.; Rajgor, R.V.

2008-01-01

A solid-phase extraction method based upon impregnation of Cyanex 302 (bis(2,4,4- trimethylpentyl)mono-thio-phosphinic acid) on Amberlite XAD-2 resin is proposed for isolation of U(VI) from uranmicrolite ore tailing samples and industrial effluent samples. U(VI) was sorbed from nitric acid media on the solvent-impregnated resin (SIR) and was recovered completely with 1.0 M HCl. Based upon sorption behavior of U(VI) with Cyanex 302, it was quantitatively sorbed on the SIR in a dynamic method, while the other metal ions were not sorbed by the modified resin. The preparation of impregnated resin is simple, based upon physical interaction of the extractant and solid support, has good sorption capacity for U(VI), and is also reliable for detection of traces of U(VI). (authors)

Cr (VI) remediation by indigenous bacteria in soils contaminated by chromium-containing slag

International Nuclear Information System (INIS)

Chai Liyuan; Huang Shunhong; Yang Zhihui; Peng Bing; Huang Yan; Chen Yuehui

2009-01-01

Hexavalent chromium (Cr) is a toxic element causing serious environmental threat. Recently, more and more attention is paid to the bio-remediation of Cr (VI) in the contaminated soils. Cr (VI) remediation by indigenous bacteria in soils contaminated by chromium-containing slag at a steel-alloy factory in Hunan Province, China, was investigated in the present study. The results showed that when sufficient nutrients were amended into the contaminated soils, total Cr (VI) concentration declined from the initial value of 462.8 to 10 mg kg -1 at 10 days and the removal rate was 97.8%. Water soluble Cr (VI) decreased from the initial concentration of 383.8 to 1.7 mg kg -1 . Exchangeable Cr (VI) and carbonates-bound Cr (VI) were removed by 92.6% and 82.4%, respectively. Meanwhile, four Cr (VI) resistant bacterial strains were isolated from the soil under the chromium-containing slag. Only one strain showed a high ability for Cr (VI) reduction in liquid culture. This strain was identified as Pannonibacter phragmitetus sp. by gene sequencing of 16S rRNA. X-ray photoelectron spectroscope (XPS) analysis indicated that Cr (VI) was reduced into trivalent chromium. The results suggest that indigenous bacterial strains have potential application for Cr (VI) remediation in the soils contaminated by chromium-containing slag.

Impact of water quality parameters on the sorption of U(VI) onto hematite

International Nuclear Information System (INIS)

Zhao Donglin; Wang Xianbiao; Yang Shitong; Guo Zhiqiang; Sheng Guodong

2012-01-01

In this study, the sorption of U(VI) from aqueous solution on hematite was studied as a function of various water quality parameters such as contact time, pH, ionic strength, soil humic acid (HA) or fulvic acid (FA), solid content and temperature by using a batch technique. The results demonstrated that the sorption of U(VI) was strongly dependent on ionic strength at pH 6.0 and the sorption was mainly dominated by inner-sphere surface complexation. The presence of HA/FA increases U(VI) sorption at low pH, whereas decreases U(VI) sorption at high pH. The thermodynamic parameters (ΔH 0 , ΔS 0 , and ΔG 0 ) were calculated from the temperature dependent sorption isotherms, and the results suggested that U(VI) sorption was a spontaneous and endothermic process. The results might be important for the application of hematite in U(VI) pollution management. Highlights: ► The sorption of U(VI) was strongly dependent on ionic strength at pH 6.0. ► A positive effect of HA/FA on U(VI) sorption was found at low pH, whereas a negative effect was observed at high pH. ► U(VI) sorption was a spontaneous and endothermic process. ► The results are quite important for the application of hematite in U(VI) pollution management.

Electrochemical processes for the environmental remediation of toxic Cr(VI): A review

International Nuclear Information System (INIS)

Jin, Wei; Du, Hao; Zheng, Shili; Zhang, Yi

2016-01-01

Highlights: • Recent advances in electrochemical technologies for practical Cr(VI) treatment applications was reviewed. • The mechanism and performance of electrocoagulation, electrochemical reduction, electrodialysis, electro-electrodialysis and electrodeionization were discussed and compared. • The remained challenges and future perspectives were commented. - Abstract: Hexavalent chromium Cr(VI) is extremely toxic and classified as one of the 17 chemicals posing the greatest threat to humans. Large amounts of Cr(VI) compounds are directly or indirectly discharged into the environment, therefore considerable efforts have been made to control the Cr(VI) concentration below the recommended level. It has been demonstrated that electrochemical technique is one of the most efficient and environmental benign approach for the Cr(VI) removal. This review aims at recent advances in electrochemical technology for practical Cr(VI) treatment applications. By using the “clean reagent” of electron, Cr(VI) can be completely eliminated or separated via different electrochemical techniques such as electrocoagulation, electrochemical reduction, electrodialysis, electro-electrodialysis and electrodeionization. Besides, the mechanism and performance of different strategies are commented and compared. The treatment process is largely dependent on variables such as pH, electrode materials, cell configuration and techniques integration. Furthermore, the remained limitation and challenges for the electrochemical Cr(VI) remediation are also discussed.

Bulk solubility and speciation of plutonium(VI) in phosphate-containing solutions

International Nuclear Information System (INIS)

Weger, H.T.; Okajima, S.; Cunnane, J.C.; Reed, D.T.

1992-01-01

The solubility and speciation of Pu(VI) with phosphate as a function of pH was investigated to determine the ability of phosphate to act as an actinide getter. The general properties were first investigated and are reported here with the goal of performing more quantitative experiments in the future. Solubility was approached from oversaturation at initial pH = 4, 10 and 13.4. Absorption spectra were recorded, the solution filtered and the filtrate counted. Absorption spectra were obtained at varying phosphate concentrations and at pH of 2.7 to 11.9. The effect of complexation on the 833 mn Pu(VI) band was characterized. Evidence for three phosphate complexes was obtained for pH -5 to 10 -6 M Pu(VI) was measured in the filtrate at pH ≤ 10 that were passed through a 50 mn filter. Pu(VI) complexes with phosphate over hydroxide at pH ≤ 11.6, but at pH ≥ 11.9, only hydrolyzed Pu(VI) was detected. At pH = 12, the concentration of Pu(VI) was as high as 10 -4 M

Bacillus lichenformis γ-glutamyl exopolymer: Physicochemical characterization and U(VI) interaction

International Nuclear Information System (INIS)

He, L.M.; Neu, M.P.; Vanderberg, L.A.

2000-01-01

Complexation by microbially produced exopolymers may significantly impact the environmental mobility and toxicity of metals. This study focused on the conformational structure of the bacterial exopolymer, γ-D-poly(glutamic acid) and its interactions with U(VI) examined using ATR-FTIR spectroscopy. Solution pH, polymer concentration, and ionic strength affected the conformation of the exopolymer, and U(VI) binding was monitored. At low pH, low concentration, or low ionic strength, this exopolymer exists in an α-helical conformation, while at high pH, concentration, or ionic strength the exopolymer exhibits a β-sheet structure. The change in exopolymer conformation is likely to influence the number and nature of exposed surface functional groups, sites most responsible for metal complexation. The authors found the polyglutamate capsule binds U(VI) in a binuclear, bidentate fashion; in contrast the glutamate monomer forms a mononuclear, bidentate complex with U(VI). The apparent polynuclear binding of U(VI) may induce β-sheet structure formation provided the U(VI) Concentration is sufficiently high

Selectivity enhancement of phosphate based functional polymeric gels towards Uranium(VI) using ion imprinting

International Nuclear Information System (INIS)

Chappa, Sankararao; Agarwal, Chhavi; Pandey, A.K.

2015-01-01

The imprinting of gel containing polymer chains of ethylene glycol methacrylate phosphate (EGMP) for U(VI) ions were carried out. The U(VI) imprinting has been carried out in pure EGMP and in EGMP: poly(ethylene glycol) methacrylate (PEGMA) = 1:9 composition. Complexation of the monomer with template (U(VI)) followed by polymerization have been used to imprint the U(VI) onto the polymer chains. The comparison of uptake studies of U(VI) and Pu(IV) at 3 M HNO 3 shows increased selectivity of U(VI) relative to Pu(IV) for both the gel compositions. The less uptake of U(VI) for imprinted EGMP:PEGMA gel relative to pure imprinted EGMP gel at tracer level can be possibly due to the requirement of two EGMP units in the vicinity for U(VI) complexation. (author)

Clinical evaluation of complete solo surgery with the "ViKY®" robotic laparoscope manipulator.

Science.gov (United States)

Takahashi, Masahiro; Takahashi, Masanori; Nishinari, Naoto; Matsuya, Hideki; Tosha, Tsutomu; Minagawa, Yukihiro; Shimooki, Osamu; Abe, Tadashi

2017-02-01

Advancement in both surgical technique and medical equipment has enabled solo surgery. ViKY ® Endoscope Positioning System (ViKY ® ) is a robotic system that remotely controls an endoscope and provides direct vision control to the surgeon. Here, we report our experience with ViKY ® -assisted solo surgery. We retrospectively examined 25 cases of solo surgery TAPP with ViKY ® . ViKY ® was setup by the surgeon alone, and the setup duration was determined as the time at which the side rail was positioned and that when the endoscope was installed. For assessing the control unit, the number of false movements was counted. We compared the operative results between ViKY ® -assisted solo surgery TAPP and the conventional method with an assistant. The average time to set up ViKY ® was 7.9 min. The average number of commands for ViKY ® during surgery was 98.3, and the average number of errors and no response of control unit was 7.9. The mean duration of surgery was 136 min for the ViKY ® group, including the setup time, and 117 min for the conventional method. No case required an assistant during the operation. There was also no difference between the two groups with regard to postoperative complications and the rate of recurrence. ViKY ® proved reliable in recognizing orders with very few failures, and the operations were performed safely and were comparable to the conventional operations with assistants. Solo surgery with ViKY ® was beneficial in this clinical evaluation.

Feedback and Incentives

DEFF Research Database (Denmark)

Eriksson, Tor Viking; Poulsen, Anders; Villeval, Marie Claire

2009-01-01

This paper experimentally investigates the impact of different pay schemes and relative performance feedback policies on employee effort. We explore three feedback rules: no feedback on relative performance, feedback given halfway through the production period, and continuously updated feedback. ...... behind, and front runners do not slack off. But in both pay schemes relative performance feedback reduces the quality of the low performers' work; we refer to this as a "negative quality peer effect"....

cis-dioxomolybdenum(VI)-(ONO)

Indian Academy of Sciences (India)

Various ONO type Schiff base ligands L(H)2 used for the preparation of ... and derivatives.6–33 Depending on the method of prepa- ration .... HCl. Scheme 6. Synthesis of a Mo(VI) Schiff base complexe by selective inversion at C–1 carbon of a ...

Multi-crystalline II-VI based multijunction solar cells and modules

Science.gov (United States)

Hardin, Brian E.; Connor, Stephen T.; Groves, James R.; Peters, Craig H.

2015-06-30

Multi-crystalline group II-VI solar cells and methods for fabrication of same are disclosed herein. A multi-crystalline group II-VI solar cell includes a first photovoltaic sub-cell comprising silicon, a tunnel junction, and a multi-crystalline second photovoltaic sub-cell. A plurality of the multi-crystalline group II-VI solar cells can be interconnected to form low cost, high throughput flat panel, low light concentration, and/or medium light concentration photovoltaic modules or devices.

Feedback in clinical education: untying the Gordian knot.

Science.gov (United States)

Weinstein, Debra F

2015-05-01

Feedback is essential to clinical education, especially in the era of competencies, milestones, and entrustable professional activities. It is, however, an area where medical educators often fall short. Although educational leaders and faculty supervisors provide feedback in a variety of clinical settings, surveys show important gaps in medical student and resident satisfaction with the feedback received, suggesting lost opportunities to identify performance problems as well as to help each learner reach his or her greatest potential.In this issue of Academic Medicine, Telio and colleagues extend the empirically validated concept of a "therapeutic alliance" to propose the "educational alliance" as a framework for enhancing feedback in medical education. They highlight the importance of source credibility, which depends on the teacher-learner relationship and alignment of values, the teacher's understanding of the learner's role and goals, the teacher's direct observation of the learner, and the learner's perception of the teacher's good intentions. The author of this Commentary suggests that the educational alliance framework should prompt medical educators to reconsider feedback and explore opportunities for optimizing it. Most medical schools and graduate medical education programs are not designed in a way that supports the education alliance model, but the Commentary author offers suggestions for cultivating educational alliances, including rethinking supervisor selection criteria. Such interventions should be combined with ongoing faculty development and efforts to improve coaching and mentoring for students, residents, and fellows. Untying the Gordian knot of effective feedback will require innovative approaches, exchange of successful strategies, and continued research.

Student Feedback of Career Development Workshops for Program Improvement

Science.gov (United States)

LeBeau, J. E.; Pressley, S. N.

2016-12-01

A number of techniques are employed each year to evaluate the effectiveness of and to identify opportunities for improvement in the Laboratory for Atmospheric Research (LAR) REU program at Washington State University. For example, information gathered from pre-/post-surveys and pre-/post-interviews provides information regarding students' perceptions and levels of experience with the scientific process, career and academic goals, and motivation for joining the REU program. Poster session rubrics assess students' abilities to summarize their experiences in a professional setting. Alumni surveys gauge former participants' perceptions of the REU experience. One seemingly simple and highly useful, but often less documented, component of the evaluation process for program improvement is the use of workshop feedback forms. Weekly workshops are designed to provide students with enhanced knowledge and skills in the area of atmospheric chemistry as well as research design skills, academic and career guidance, and presentation skills. According to previous years' evaluation reports, workshops are largely beneficial to students for learning new skills. Yet, students suggest a number of recommendations that may benefit any REU program, such as: providing slides beforehand to provide a framework for the upcoming workshop, having instructors speak in more student-friendly language, covering higher-level topics, and including more hands-on, instructor-guided practice during the workshops. Thus, workshop feedback forms provide meaningful feedback to increase learning outcomes and enhance the REU student experience. This presentation will offer ideas gathered from over five years of workshop feedback forms that, while somewhat specific to workshops offered for the LAR REU, can offer faculty and PIs insight into the student experience, enhancing their ability to improve programming and achieve greater learning outcomes.

24 CFR 972.115 - Relationship between required conversions and HOPE VI developments.

Science.gov (United States)

2010-04-01

... conversions and HOPE VI developments. 972.115 Section 972.115 Housing and Urban Development Regulations... Relationship between required conversions and HOPE VI developments. HUD actions to approve or deny proposed HOPE VI revitalization plans must be consistent with the requirements of this subpart. Developments...

Enhanced Cr(VI) removal by polyethylenimine- and phosphorus-codoped hierarchical porous carbons.

Science.gov (United States)

Chen, Shixia; Wang, Jun; Wu, Zeliang; Deng, Qiang; Tu, Wenfeng; Dai, Guiping; Zeng, Zheling; Deng, Shuguang

2018-08-01

The amino- and phosphorus-codoped (N,P-codoped) porous carbons derived from oil-tea shells were facilely fabricated through a combination of phosphoric acid (H 3 PO 4 ) activation and amino (polyethylenimine, PEI) modification method. The as-synthesized carbon adsorbents were systematically characterized and evaluated for Cr(VI) removal in aqueous solutions. The relationship between adsorbent properties and adsorption behaviors was illustrated. Moreover, the influences of contact time, initial Cr(VI) concentration, pH, coexisting anions and temperature were also investigated. The adsorption behavior of Cr(VI) could be perfectly described by the pseudo-second-order kinetic model and Sips adsorption model. The maximum adsorption capacity of Cr(VI) on the carbon adsorbents synthesized in this work was 355.0 mg/g, and this excellent Cr(VI) capacity could be sustained with other coexisting anions. In addition to high surface area and suitable pore size distribution, the high Cr(VI) removal capacity is induced by rich heteroatoms incorporation and the Cr(VI) removal mechanism was clearly illustrated. Furthermore, the continuous column breakthrough experiment on obtained N,P-codoped carbon was conducted and well fitted by the Thomas model. This work revealed that PEI modification and P-containing groups could significantly enhance Cr(VI) adsorption capacity and make these N,P-codoped biomass-derived carbons potent adsorbents in practical water treatment applications. Copyright © 2018 Elsevier Inc. All rights reserved.

ASD Customer Satisfaction Survey

Data.gov (United States)

Department of Veterans Affairs — ASD implemented a customer satisfaction survey for our products and services. This feedback will provide a better understanding of how ASD products and services can...

A combined wet chemistry and EXAFS study of U(VI) uptake by cementitious materials

International Nuclear Information System (INIS)

Wieland, E.; Harfouche, M.; Tits, J.; Kunz, D.; Daehn, R.; Fujita, T.; Tsukamoto, M.

2006-01-01

The sorption behaviour and speciation of U(VI) in cementitious systems was investigated by a combination of wet chemistry experiments and synchrotron-based X-ray absorption spectroscopy (XAS) measurements. Radiotracer studies using 233 U were carried out on hardened cement paste (HCP) and calcium silicate hydrates (C-S-H), which are the major constituents of HCP, to determine the uptake kinetics and sorption isotherms. C-S-H phases were synthesized using different methods for solid phase preparation, which enabled us to study the U(VI) uptake by different types of C-S-H phases and a wide range of Ca/Si compositions, and to distinguish U(VI) sorption on the surface of C-S-H from U(VI) incorporation into the structure. XAS measurements were performed using U(VI) loaded HCP and C-S-H materials (sorption and co-precipitation samples) to gain structural information on the U(VI) speciation in these systems, i.e., the type and number of neighbouring atoms, and bond distances. Examples of studies that have utilized XAS to characterize U(VI) speciation in cementitious systems are still rare, and to the best of our knowledge, detailed XAS investigations of the U(VI)/C-S-H system are lacking. The results obtained from the combined use of wet chemical and spectroscopic techniques allow mechanistic models of the immobilization process to be proposed for cementitious waste forms containing low and high U(VI) inventories. In the latter case U(VI) immobilization is controlled by a solubility-limiting process with the U(VI) mineral predominantly formed under the conditions prevailing in cementitious systems. At low U(VI) concentrations, however, U(VI) appears to be predominantly bound onto C-S-H phases. The coordination environment of U(VI) taken up by C-S-H was found to resemble that of U(VI) in uranophane. A mechanistic understanding of the U(VI) binding by cementitious materials will allow more detailed and scientifically well founded predictions of the retention of

Contribution of extracellular polymeric substances from Shewanella sp. HRCR-1 biofilms to U(VI) immobilization.

Science.gov (United States)

Cao, Bin; Ahmed, Bulbul; Kennedy, David W; Wang, Zheming; Shi, Liang; Marshall, Matthew J; Fredrickson, Jim K; Isern, Nancy G; Majors, Paul D; Beyenal, Haluk

2011-07-01

The goal of this study was to quantify the contribution of extracellular polymeric substances (EPS) to U(VI) immobilization by Shewanella sp. HRCR-1. Through comparison of U(VI) immobilization using cells with bound EPS (bEPS) and cells with minimal EPS, we show that (i) bEPS from Shewanella sp. HRCR-1 biofilms contribute significantly to U(VI) immobilization, especially at low initial U(VI) concentrations, through both sorption and reduction; (ii) bEPS can be considered a functional extension of the cells for U(VI) immobilization and they likely play more important roles at lower initial U(VI) concentrations; and (iii) the U(VI) reduction efficiency is dependent upon the initial U(VI) concentration and decreases at lower concentrations. To quantify the relative contributions of sorption and reduction to U(VI) immobilization by EPS fractions, we isolated loosely associated EPS (laEPS) and bEPS from Shewanella sp. HRCR-1 biofilms grown in a hollow fiber membrane biofilm reactor and tested their reactivity with U(VI). We found that, when reduced, the isolated cell-free EPS fractions could reduce U(VI). Polysaccharides in the EPS likely contributed to U(VI) sorption and dominated the reactivity of laEPS, while redox active components (e.g., outer membrane c-type cytochromes), especially in bEPS, possibly facilitated U(VI) reduction.

Sorption of chromium (VI) by Mg/Fe hydrotalcite type compunds

Energy Technology Data Exchange (ETDEWEB)

García-Sosa, I., E-mail: irma.garcia@inin.gob.mx; Cabral-Prieto, A., E-mail: agustin.cabral@inin.gob.mx [Instituto Nacional de Investigaciones Nucleares, Departamento de Química (Mexico); Nava, N., E-mail: tnava@imp.mx; Navarrete, J. [Instituto Mexicano del Petróleo (Mexico); Olguín, M. T., E-mail: teresa.olguin@inin.gob.mx [Instituto Nacional de Investigaciones Nucleares, Departamento de Química (Mexico); Escobar, Luis, E-mail: luis.escobar@inin.gob.mx [Instituto Nacional de Investigaciones Nucleares, Departamento de Física (Mexico); López-Castañares, R., E-mail: rlc@anuies.mx; Olea-Cardoso, O., E-mail: olc@anuies.mx [Universidad Autónoma del Edo. de México, Facultad de Química (Mexico)

2015-06-15

The synthesis by co-precipitation and characterization by X-ray diffraction, Raman and Mössbauer spectroscopies of Mg-Fe-hydrotalcite compounds, and their sorption capacities for Cr(VI) in aqueous media were carried out. The average sorption capacity of Cr(VI) for the non-thermal treated samples was of 6.2 mg/g. The ferrihydrite was omnipresent in all prepared hydrotalcite samples. A brief discussion is made on the role of both the hydrotalcite and ferrihydrite for removing such amount of Cr(VI)

Uranium(VI) retention on quartz and kaolinite. Experiments and modelling

International Nuclear Information System (INIS)

Mignot, G.

2001-01-01

The behaviour of uranium in the geosphere is an important issue for safety performance assessment of nuclear waste repositories, or in the context of contaminated sites due to mining activity related to nuclear field. Under aerobic conditions, the fate of uranium is mainly governed by the ability of minerals to sorb U(VI) aqueous species. Hence, a thorough understanding of U(VI) sorption processes on minerals is required to provide a valuable prediction of U(VI) migration in the environment. In this study, we performed sorption/desorption experiments of U(VI) on quartz and kaolinite, for systems favouring the formation in solution (i) of UO 2 2+ and monomeric hydrolysis products or (ii) of di-/tri-meric uranyl aqueous species, and / or U(VI)-colloids or UO 2 (OH) 2 precipitates, or (iii) of uranyl-carbonate complexes. Particular attention was paid to determine the surface characteristics of the solids and their modification due to dissolution/precipitation processes during experiments. A double layer surface complexation model was applied to our experimental data in order to derive surface complexation equilibria and intrinsic constants which allow a valuable description of U(VI) retention over a wide range of pH, ionic strength, initial concentration of uranium [0.1-10μM] and solid - solution equilibration time. U(VI) sorption on quartz was successfully modeled by using two sets of adsorption equilibria, assuming (i) the formation of the surface complexes SiOUO 2 + , SiOUO 2 OH and SiO(UO 2 ) 3 (OH) 5 , or (ii) the formation of the mono-dentate complex SiO(UO 2 ) 3 (OH) 5 and of the bidentate complex (SiO) 2 UO 2 . Assumptions on the density of each type of surface sites of kaolinite and on their acid-base properties were made from potentiometric titrations of kaolinite suspensions. We proposed on such a basis a set of surface complexation equilibria which accounts for U(VI) uptake on kaolinite over a wide range of chemical conditions, with aluminol edge sites as

strong>Hvad skal vi med en hjerne?strong>

DEFF Research Database (Denmark)

Hermansen, Judy

2009-01-01

neurologen Antonio Damasio, at sikre vores overlevelse og velbefindende (i nævnte rækkefølge). Vi ved, at der findes såkaldte belønningsstrukturer i hjernen på både dyr og mennesker, som aktiverer følelser af velbehag, når vi gør "det rigtige", dvs. noget der er godt for os. Men hvordan de mere konkret...

Reduction of Cr(VI) in aqueous solution with DC diaphragm glow discharge

International Nuclear Information System (INIS)

Wang, Xiaoyan; Jin, Xinglong; Zhou, Minghua; Chen, Zhenhai; Deng, Kai

2013-01-01

This paper investigated the reduction of Cr(VI) in aqueous solution with direct current diaphragm glow discharge (DGD). The glow discharge sustained around the hole on a quartz tube which divided the electrolyte cell into two parts. The reduction efficiencies of Cr(VI) under different applied voltages, initial conductivities, hole diameters, hole numbers, initial pH values and initial concentrations were systematically studied. The results showed that the reduction efficiency of Cr(VI) increased with the increase of applied voltage, initial conductivity, hole diameter and hole number. The different initial pH values showed less effects on the reduction of Cr(VI). The reduction efficiency decreased with the increasing initial concentration. In addition, the simultaneous reduction of Cr(VI) and decolorization of acid orange (AO) with DGD were also fulfilled. Furthermore, the energy efficiency for Cr(VI) reduction with DGD was calculated and compared with those in photocatalysis and other glow discharge reactor

Characterization of U(VI)-carbonato ternary complexes on hematite: EXAFS and electrophoretic mobility measurements

Science.gov (United States)

Bargar, John R.; Reitmeyer, Rebecca; Lenhart, John J.; Davis, James A.

2000-01-01

We have measured U(VI) adsorption on hematite using EXAFS spectroscopy and electrophoresis under conditions relevant to surface waters and aquifers (0.01 to 10 μM dissolved uranium concentrations, in equilibrium with air, pH 4.5 to 8.5). Both techniques suggest the existence of anionic U(VI)-carbonato ternary complexes. Fits to EXAFS spectra indicate that U(VI) is simultaneously coordinated to surface FeO6 octahedra and carbonate (or bicarbonate) ligands in bidentate fashions, leading to the conclusion that the ternary complexes have an inner-sphere metal bridging (hematite-U(VI)-carbonato) structure. Greater than or equal to 50% of adsorbed U(VI) was comprised of monomeric hematite-U(VI)-carbonato ternary complexes, even at pH 4.5. Multimeric U(VI) species were observed at pH ≥ 6.5 and aqueous U(VI) concentrations approximately an order of magnitude more dilute than the solubility of crystalline β-UO2(OH)2. Based on structural constraints, these complexes were interpreted as dimeric hematite-U(VI)-carbonato ternary complexes. These results suggest that Fe-oxide-U(VI)-carbonato complexes are likely to be important transport-limiting species in oxic aquifers throughout a wide range of pH values.

Extraction kinetics of uranium (VI) with polyurethane foam

International Nuclear Information System (INIS)

Huang, Ting-Chia; Chen, Dong-Hwang; Huang, Shius-Dong; Huang, Ching-Tsven; Shieh, Mu-Chang.

1993-01-01

The extraction kinetics of uranium(VI) from aqueous nitrate solution with polyether-based polyurethane foam was investigated in a batch reactor with automatic squeezing. The extraction curves of uranium(VI) concentration in solution vs. extraction time exhibited a rather rapid exponential decay within the first few minutes, followed by a slower exponential decay during the remaining period. This phenomenon can be attributed to the presence of two-phase structure, hard segment domains and soft segment matrix in the polyurethane foam. A two-stage rate model expressed by a superposition of two exponential curves was proposed, according to which the experimental data were fitted by an optimization method. The extraction rate of uranium (VI) was also found to increase with increasing temperature, nitrate concentration, and hydration of the cation of nitrate salt. (author)

Adsorption of Cr(VI and Speciation of Cr(VI and Cr(III in Aqueous Solutions Using Chemically Modified Chitosan

Directory of Open Access Journals (Sweden)

ChunYuan Tao

2012-05-01

Full Text Available A new type of grafting chitosan (CTS was synthesized using 2-hydroxyethyl- trimethyl ammonium chloride (HGCTS. The adsorption of Cr(VI on HGCTS was studied. The effect factors on adsorption and the adsorption mechanism were considered. The results indicated that the HGCTS could concentrate and separate Cr(VI at pH 4.0; the adsorption equilibrium time was 80 min; the maximum adsorption capacity was 205 mg/g. The adsorption isotherm and kinetics were investigated, equilibrium data agreed very well with the Langmuir model and the pseudo second-order model could describe the adsorption process better than the pseudo first-order model. A novel method for speciation of Cr(VI and Cr(III in environmental water samples has been developed using HGCTS as adsorbent and FAAS as determination means. The detection limit of this method was 20 ng/L, the relatively standard deviation was 1.2% and the recovery was 99%~105%.

Wavelengths and energy levels of I V and I VI

International Nuclear Information System (INIS)

Kaufman, V.; Sugar, J.; Joshi, Y.N.

1988-01-01

The spectra of iodine were photographed in the 139--1500-Aat;O region on various spectrographs. Earlier analyses of I V and I VI were revised and extended. For I V 26 lines were classified, and for I VI 35 lines were classified. Ionization energies have been estimated to be 415 510 atm≅ 300 cm -1 (51.52 atm≅ 0.04 eV) and 599 800 atm≅ 3 000 cm -1 (74.37 atm≅ 0.37 eV) for I V and I VI, respectively

Group ib organometallic chemistry. XXXIV. Thermal behaviour and chemical reactivity of tetranuclear Me2N-substituted diarypropenylcopper-copper anion (Vi2Cu4X2) and mixed diarylpropenyl/organocopper (Vi2Cu4R2) compounds

NARCIS (Netherlands)

Hoedt, R.W.M. ten; Koten, G. van; Noltes, J.G.

1980-01-01

Thermal decomposition of configurationally pure 1,2-diarylpropenylcopper compounds Z-Vi2CU4Br2 and Z-Vi2Cu4R2 [Vi = (2-Me2NC6H4)C=C(Me)-(C6H4Me-4), R = 2-Me2NC6H4 or 4-MeC6H4CC] predominantly results in the formation of ViH. In contrast, only dimers (ViVi) were formed on thermolysis of (Z-ViCu2OTf)η

Intervening O vi Quasar Absorption Systems at Low Redshift: A Significant Baryon Reservoir.

Science.gov (United States)

Tripp; Savage; Jenkins

2000-05-01

Far-UV echelle spectroscopy of the radio-quiet QSO H1821+643 (zem=0.297), obtained with the Space Telescope Imaging Spectrograph (STIS) at approximately 7 km s-1 resolution, reveals four definite O vi absorption-line systems and one probable O vi absorber at 0.15quasar in redshift; these are likely intervening systems unrelated to the background QSO. In the case of the strong O vi system at zabs=0.22497, multiple components are detected in Si iii and O vi as well as H i Lyman series lines, and the differing component velocity centroids and b-values firmly establish that this is a multiphase absorption system. A weak O vi absorber is detected at zabs=0.22637, i.e., offset by approximately 340 km s-1 from the zabs=0.22497 system. Lyalpha absorption is detected at zabs=0.22613, but no Lyalpha absorption is significantly detected at 0.22637. Other weak O vi absorbers at zabs=0.24531 and 0.26659 and the probable O vi system at 0.21326 have widely diverse O vi/H i column density ratios with N(O vi)/N(H i) ranging from vi absorbers with rest equivalent width greater than 30 mÅ in the H1821+643 spectrum is remarkably high, dN&solm0;dz approximately 48, which implies with a high (90%) confidence that it is greater than 17 in the low-redshift intergalactic medium. We conservatively estimate that the cosmological mass density of the O vi systems is Omegab(Ovi&parr0; greater, similar0.0008 h-175. With an assumed metallicity of 1/10 solar and a conservative assumption that the fraction of oxygen in the O vi ionization stage is 0.2, we obtain Omegab(Ovi&parr0; greater, similar0.004 h-175. This is comparable to the combined cosmological mass density of stars and cool gas in galaxies and X-ray-emitting gas in galaxy clusters at low redshift.

On halide derivatives of rare-earth metal(III) oxidomolybdates(VI) and -tungstates(VI)

International Nuclear Information System (INIS)

Schleid, Thomas; Hartenbach, Ingo

2016-01-01

Halide derivatives of rare-earth metal(III) oxidomolybdates(VI) have been investigated comprehensively over the last decade comprising the halogens fluorine, chlorine, and bromine. Iodide-containing compounds are so far unknown. The simple composition REXMoO 4 (RE=rare-earth element, X=halogen) is realized for X=F almost throughout the complete lanthanide series as well as for yttrium. While ytterbium and lutetium do not form any fluoride derivative, for lanthanum, only a fluoride-deprived compound with the formula La 3 FMo 4 O 16 is realized. Moreover, molybdenum-rich compounds with the formula REXMo 2 O 7 are also known for yttrium and the smaller lanthanoids. For X=Cl the composition REClMoO 4 is known for yttrium and the whole lanthanide series, although, four different structure types were identified. Almost the same holds for X=Br, however, only two different structure types are realized in this class of compounds. In the case of halide derivatives of rare-earth metal(III) oxidotungstates(VI) the composition REXWO 4 is found for chlorides and bromides only, so far. Due to the similar size of Mo 6+ and W 6+ cations, the structures found for the tungstates are basically the same as for the molybdates. With the larger lanthanides, the representatives for both chloride and bromide derivates exhibit similar structural motifs as seen in the molybdates, however, the crystal structure cannot be determined reliably. In case of the smaller lanthanoids, the chloride derivatives are isostructural with the respective molybdates, although the existence ranges differ slightly. The same is true for rare-earth metal(III) bromide oxidotungstates(VI).

Written Corrective Feedback: The Perception of Korean EFL Learners

Science.gov (United States)

Chung, Bohyon

2015-01-01

This paper reports on the perception of Korean EFL learners toward feedback types on their written errors. The survey was administered using an adopted questionnaire from previous studies (Ishii 2011; Leki, 1991). This further allows a comparison of Korean EFL learners' attitudes with the responses to an identical questionnaire by Japanese EFL…

How are things going. Obtaining feedback in a regulatory environment

International Nuclear Information System (INIS)

McGuire, J.V.; Walsh, M.E.; Boegel, A.J.; Morisseau, D.S.; Persendky, J.J.

1984-08-01

This study tested two procedures to gather feedback for a federal agency about its regulatory actions and its licensees' practices. The procedures, a workshop and a mailed survey, targeted a data source new to the agency. Results to date find the feedback workshop useful and the new data source cooperative and valuable. Participation in the workshops is surprising, given their historical backdrop, structure, and psychological literatures. These findings suggest that agencies may be ignoring important data sources for ill-informed reasons. Also, the findings suggest a possible need to restructure existing channels of communication between a regulatory agency and its licensees

Feedback on Feedback--Does It Work?

Science.gov (United States)

Speicher, Oranna; Stollhans, Sascha

2015-01-01

It is well documented that providing assessment feedback through the medium of screencasts is favourably received by students and encourages deeper engagement with the feedback given by the language teacher (inter alia Abdous & Yoshimura, 2010; Brick & Holmes, 2008; Cann, 2007; Stannard, 2007). In this short paper we will report the…

Uranium(VI) Reduction by Nanoscale Zerovalent Iron in Anoxic Batch Systems

International Nuclear Information System (INIS)

Yan, Sen; Hua, Bin; Bao, Zhengyu; Yang, John; Liu, Chongxuan; Deng, Baolin

2010-01-01

This study investigated the influences of pH, bicarbonate, and calcium on U(VI) adsorption and reduction by synthetic nanosize zero valent iron (nano Fe 0 ) particles under an anoxic condition. The results showed that about 87.1%, 82.7% and 78.3% of U(VI) could be reduced within 96 hours in the presence of 10 mM bicarbonate at pHs 6.92, 8.03 and 9.03, respectively. The rates of U(VI) reduction and adsorption by nano Fe 0 , however, varied significantly with increasing pH and concentrations of bicarbonate and/or calcium. Solid phase analysis by X-ray photoelectron spectroscopy confirmed the formation of UO 2 and iron (hydr)oxides as a result of the redox interactions between adsorbed U(VI) and nano Fe 0 . This study highlights the potential important role of groundwater chemical composition in controlling the rates of U(VI) reductive immobilization using nano Fe 0 in subsurface environments.

Extractive behavior of U(VI) in the paraffin soluble ionic liquid

International Nuclear Information System (INIS)

Rama, R.; Kumaresan, R.; Venkatesan, K.A.; Antony, M.P.; Vasudeva Rao, P.R.

2013-01-01

An Aliquat-336 based ionic liquid namely, tri-n-octylmethylammonium bis(2-ethylhexyl)phosphate ((A3636) + (DEHP) - ) was prepared and studied for the extraction of U(VI) from nitric acid medium. Since the ionic liquid, (A336) + (DEHP) - , was miscible in n-dodecane (n-DD), the extraction of U(VI) in the solution of tri-n-butylphosphate (TBP) in n-DD, was investigated in the presence of small concentrations of ionic liquid. The distribution ratio of U(VI) in 0.3 M (A336) + (DEHP) - /n-DD decreased with increase in the concentration of nitric acid. The effect of concentration of TBP, ionic liquid nitric acid and nitrate ion on the extraction of U(VI) in ionic liquid medium was studied. The mechanistic aspect of extraction was investigated by the slope analysis of the extraction data. The studies indicated the feasibility of modifying the extractive properties of U(VI) in TBP/n-DD using ionic liquid. (author)

Gravimetric determination of uranium(VI) and thorium(IV) with substituted pyrazolones

International Nuclear Information System (INIS)

Arora, H.C.; Rao, G.N.

1981-01-01

4-Acylpyrazolones like 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP), 1-phenyl-3-methyl-4-p-nitrobenzoyl-5-pyrazolone (PMNP) and 1-phenyl-3-methyl-4-(3,5 dinitrobenzoyl)-5-pyrazolone (PMDP) have been synthesized and developed as gravimetric reagents for the determination of U(VI) and Th(IV). Uranium(VI) is almost quantitatively precipitated with PMBP, PMNP, and PMDP at pH 2.20, 1.85 and 1.70 respectively. The pH values for the complete precipitation of thorium(IV) with PMBP, PMNP and PMDP are 2.90, 2.75 and 2.50 respectively. PMBP has proved to be an efficient ligand for gravimetric determination of U(VI) by direct weighing method after drying at 100 +- 10 deg C. The percentage relative error varies from 0.4 to 1.6 in the determination of U(VI) by this method. The effect of a number of interfering ions on the precipitation of U(VI) by PMBP has been reported. (author)

ViCTree: An automated framework for taxonomic classification from protein sequences.

Science.gov (United States)

Modha, Sejal; Thanki, Anil; Cotmore, Susan F; Davison, Andrew J; Hughes, Joseph

2018-02-20

The increasing rate of submission of genetic sequences into public databases is providing a growing resource for classifying the organisms that these sequences represent. To aid viral classification, we have developed ViCTree, which automatically integrates the relevant sets of sequences in NCBI GenBank and transforms them into an interactive maximum likelihood phylogenetic tree that can be updated automatically. ViCTree incorporates ViCTreeView, which is a JavaScript-based visualisation tool that enables the tree to be explored interactively in the context of pairwise distance data. To demonstrate utility, ViCTree was applied to subfamily Densovirinae of family Parvoviridae. This led to the identification of six new species of insect virus. ViCTree is open-source and can be run on any Linux- or Unix-based computer or cluster. A tutorial, the documentation and the source code are available under a GPL3 license, and can be accessed at http://bioinformatics.cvr.ac.uk/victree_web/. sejal.modha@glasgow.ac.uk.

Contribution of Extracellular Polymeric Substances from Shewanella sp. HRCR-1 Biofilms to U(VI) Immobilization

Energy Technology Data Exchange (ETDEWEB)

Cao, Bin; Ahmed, B.; Kennedy, David W.; Wang, Zheming; Shi, Liang; Marshall, Matthew J.; Fredrickson, Jim K.; Isern, Nancy G.; Majors, Paul D.; Beyenal, Haluk

2011-06-05

The goal of this study was to quantify the contribution of extracellular polymeric substances (EPS) in U(VI) immobilization by Shewanella sp. HRCR-1. Through comparison of U(VI) immobilization using cells with bound EPS (bEPS) and cells without EPS, we showed that i) bEPS from Shewanella sp. HRCR-1 biofilms contributed significantly to U(VI) immobilization, especially at low initial U(VI) concentrations, through both sorption and reduction; ii) bEPS could be considered as a functional extension of the cells for U(VI) immobilization and they likely play more important roles at initial U(VI) concentrations; and iii) U(VI) reduction efficiency was found to be dependent upon initial U(VI) concentration and the efficiency decreased at lower concentrations. To quantify relative contribution of sorption and reduction in U(VI) immobilization by EPS fractions, we isolated loosely associated EPS (laEPS) and bEPS from Shewanella sp. HRCR-1 biofilms grown in a hollow fiber membrane biofilm reactor and tested their reactivity with U(V). We found that, when in reduced form, the isolated cell-free EPS fractions could reduce U(VI). Polysaccharides in the EPS likely contributed to U(VI) sorption and dominated reactivity of laEPS while redox active components (e.g., outer membrane c-type cytochromes), especially in bEPS, might facilitate U(VI) reduction.

Differential Killing of Salmonella enterica Serovar Typhi by Antibodies Targeting Vi and Lipopolysaccharide O:9 Antigen.

Directory of Open Access Journals (Sweden)

Peter J Hart

Full Text Available Salmonella enterica serovar Typhi expresses a capsule of Vi polysaccharide, while most Salmonella serovars, including S. Enteritidis and S. Typhimurium, do not. Both S. Typhi and S. Enteritidis express the lipopolysaccharide O:9 antigen, yet there is little evidence of cross-protection from anti-O:9 antibodies. Vaccines based on Vi polysaccharide have efficacy against typhoid fever, indicating that antibodies against Vi confer protection. Here we investigate the role of Vi capsule and antibodies against Vi and O:9 in antibody-dependent complement- and phagocyte-mediated killing of Salmonella. Using isogenic Vi-expressing and non-Vi-expressing derivatives of S. Typhi and S. Typhimurium, we show that S. Typhi is inherently more sensitive to serum and blood than S. Typhimurium. Vi expression confers increased resistance to both complement- and phagocyte-mediated modalities of antibody-dependent killing in human blood. The Vi capsule is associated with reduced C3 and C5b-9 deposition, and decreased overall antibody binding to S. Typhi. However, purified human anti-Vi antibodies in the presence of complement are able to kill Vi-expressing Salmonella, while killing by anti-O:9 antibodies is inversely related to Vi expression. Human serum depleted of antibodies to antigens other than Vi retains the ability to kill Vi-expressing bacteria. Our findings support a protective role for Vi capsule in preventing complement and phagocyte killing of Salmonella that can be overcome by specific anti-Vi antibodies, but only to a limited extent by anti-O:9 antibodies.

Differential Killing of Salmonella enterica Serovar Typhi by Antibodies Targeting Vi and Lipopolysaccharide O:9 Antigen.

Science.gov (United States)

Hart, Peter J; O'Shaughnessy, Colette M; Siggins, Matthew K; Bobat, Saeeda; Kingsley, Robert A; Goulding, David A; Crump, John A; Reyburn, Hugh; Micoli, Francesca; Dougan, Gordon; Cunningham, Adam F; MacLennan, Calman A

2016-01-01

Salmonella enterica serovar Typhi expresses a capsule of Vi polysaccharide, while most Salmonella serovars, including S. Enteritidis and S. Typhimurium, do not. Both S. Typhi and S. Enteritidis express the lipopolysaccharide O:9 antigen, yet there is little evidence of cross-protection from anti-O:9 antibodies. Vaccines based on Vi polysaccharide have efficacy against typhoid fever, indicating that antibodies against Vi confer protection. Here we investigate the role of Vi capsule and antibodies against Vi and O:9 in antibody-dependent complement- and phagocyte-mediated killing of Salmonella. Using isogenic Vi-expressing and non-Vi-expressing derivatives of S. Typhi and S. Typhimurium, we show that S. Typhi is inherently more sensitive to serum and blood than S. Typhimurium. Vi expression confers increased resistance to both complement- and phagocyte-mediated modalities of antibody-dependent killing in human blood. The Vi capsule is associated with reduced C3 and C5b-9 deposition, and decreased overall antibody binding to S. Typhi. However, purified human anti-Vi antibodies in the presence of complement are able to kill Vi-expressing Salmonella, while killing by anti-O:9 antibodies is inversely related to Vi expression. Human serum depleted of antibodies to antigens other than Vi retains the ability to kill Vi-expressing bacteria. Our findings support a protective role for Vi capsule in preventing complement and phagocyte killing of Salmonella that can be overcome by specific anti-Vi antibodies, but only to a limited extent by anti-O:9 antibodies.

Spectroscopic confirmation of uranium(VI)-carbonato adsorption complexes on hematite

Science.gov (United States)

Bargar, John R.; Reitmeyer, Rebecca; Davis, James A.

1999-01-01

Evaluating societal risks posed by uranium contamination from waste management facilities, mining sites, and heavy industry requires knowledge about uranium transport in groundwater, often the most significant pathway of exposure to humans. It has been proposed that uranium mobility in aquifers may be controlled by adsorption of U(VI)−carbonato complexes on oxide minerals. The existence of such complexes has not been demonstrated, and little is known about their compositions and reaction stoichiometries. We have used attenuated total reflectance Fourier transform infrared (ATR-FTIR) and extended X-ray absorption fine structure (EXAFS) spectroscopies to probe the existence, structures, and compositions of ≡FeOsurface−U(VI)−carbonato complexes on hematite throughout the pH range of uranyl uptake under conditions relevant to aquifers. U(VI)−carbonato complexes were found to be the predominant adsorbed U(VI) species at all pH values examined, a much wider pH range than previously postulated based on analogy to aqueous U(VI)−carbonato complexes, which are trace constituents at pH carbonato complexes may be of major importance to the groundwater transport of similar actinide contaminants such as neptunium and plutonium.

Bicarbonate Impact on U(VI) Bioreduction in a Shallow Alluvial Aquifer

Energy Technology Data Exchange (ETDEWEB)

Long, Philip E.; Williams, Kenneth H.; Davis, James A.; Fox, Patricia M.; Wilkins, Michael J.; Yabusaki, Steven B.; Fang, Yilin; Waichler, Scott R.; Berman, Elena S.; Gupta, Manish; Chandler, Darrell P.; Murray, Christopher J.; Peacock, Aaron D.; Giloteaux, L.; Handley, Kim M.; Lovley, Derek R.; Banfield, Jillian F.

2015-02-01

Field-scale biostimulation and desorption tracer experiments conducted in a uranium (U) contaminated, shallow alluvial aquifer have provided insight into the coupling of microbiology, biogeochemistry, and hydrogeology that control U mobility in the subsurface. Initial experiments successfully tested the concept that Fe-reducing bacteria such as Geobacter sp. could enzymatically reduce soluble U(VI) to insoluble U(IV) during in situ electron donor amendment (Anderson et al. 2003, Williams et al. 2011). In parallel, in situ desorption tracer tests using bicarbonate amendment demonstrated rate-limited U(VI) desorption (Fox et al. 2012). These results and prior laboratory studies underscored the importance of enzymatic U(VI)-reduction and suggested the ability to combine desorption and bioreduction of U(VI). Here we report the results of a new field experiment in which bicarbonate-promoted uranium desorption and acetate amendment were combined and compared to an acetate amendment-only experiment in the same experimental plot. Results confirm that bicarbonate amendment to alluvial aquifer desorbs U(VI) and increases the abundance of Ca-uranyl-carbonato complexes. At the same time, that the rate of acetate-promoted enzymatic U(VI) reduction was greater in the presence of added bicarbonate in spite of the increased dominance of Ca-uranyl-carbonato aqueous complexes. A model-simulated peak rate of U(VI) reduction was ~3.8 times higher during acetate-bicarbonate treatment than under acetate-only conditions. Lack of consistent differences in microbial community structure between acetate-bicarbonate and acetate-only treatments suggest that a significantly higher rate of U(VI) reduction the bicarbonate-impacted sediment may be due to a higher intrinsic rate of microbial reduction induced by elevated concentrations of the bicarbonate oxyanion. The findings indicate that bicarbonate amendment may be useful in improving the engineered bioremediation of uranium in aquifers.

Bicarbonate impact on U(VI) bioreduction in a shallow alluvial aquifer

Science.gov (United States)

Long, Philip E.; Williams, Kenneth H.; Davis, James A.; Fox, Patricia M.; Wilkins, Michael J.; Yabusaki, Steven B.; Fang, Yilin; Waichler, Scott R.; Berman, Elena S. F.; Gupta, Manish; Chandler, Darrell P.; Murray, Chris; Peacock, Aaron D.; Giloteaux, Ludovic; Handley, Kim M.; Lovley, Derek R.; Banfield, Jillian F.

2015-02-01

Field-scale biostimulation and desorption tracer experiments conducted in a uranium (U) contaminated, shallow alluvial aquifer have provided insight into the coupling of microbiology, biogeochemistry, and hydrogeology that control U mobility in the subsurface. Initial experiments successfully tested the concept that Fe-reducing bacteria such as Geobacter sp. could enzymatically reduce soluble U(VI) to insoluble U(IV) during in situ electron donor amendment (Anderson et al., 2003; Williams et al., 2011). In parallel, in situ desorption tracer tests using bicarbonate amendment demonstrated rate-limited U(VI) desorption (Fox et al., 2012). These results and prior laboratory studies underscored the importance of enzymatic U(VI)-reduction and suggested the ability to combine desorption and bioreduction of U(VI). Here we report the results of a new field experiment in which bicarbonate-promoted uranium desorption and acetate amendment were combined and compared to an acetate amendment-only experiment in the same experimental plot. Results confirm that bicarbonate amendment to alluvial aquifer sediments desorbs U(VI) and increases the abundance of Ca-uranyl-carbonato complexes. At the same time, the rate of acetate-promoted enzymatic U(VI) reduction was greater in the presence of added bicarbonate in spite of the increased dominance of Ca-uranyl-carbonato aqueous complexes. A model-simulated peak rate of U(VI) reduction was ∼3.8 times higher during acetate-bicarbonate treatment than under acetate-only conditions. Lack of consistent differences in microbial community structure between acetate-bicarbonate and acetate-only treatments suggest that a significantly higher rate of U(VI) reduction in the bicarbonate-impacted sediment may be due to a higher intrinsic rate of microbial reduction induced by elevated concentrations of the bicarbonate oxyanion. The findings indicate that bicarbonate amendment may be useful in improving the engineered bioremediation of uranium in

Comparative Visual Analysis of Large Customer Feedback Based on Self-Organizing Sentiment Maps

OpenAIRE

Janetzko, Halldór; Jäckle, Dominik; Schreck, Tobias

2013-01-01

Textual customer feedback data, e.g., received by surveys or incoming customer email notifications, can be a rich source of information with many applications in Customer Relationship Management (CRM). Nevertheless, to date this valuable source of information is often neglected in practice, as service managers would have to read manually through potentially large amounts of feedback text documents to extract actionable information. As in many cases, a purely manual approach is not feasible, w...

Mechanism of uranium (VI) removal by two anaerobic bacterial communities

Energy Technology Data Exchange (ETDEWEB)

Martins, Monica [Centro de Ciencias do Mar, Universidade do Algarve, FCT-DQF (edificio 8), Campus de Gambelas, 8005-139 Faro (Portugal); Faleiro, Maria Leonor [IBB - Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, FCT, Campus de Gambelas, 8005-139 Faro (Portugal); Costa, Ana M. Rosa da [Centro de Investigacao em Quimica do Algarve, Universidade do Algarve, FCT, DQF, Campus de Gambelas, 8005-139 Faro (Portugal); Chaves, Sandra; Tenreiro, Rogerio [Universidade de Lisboa, Faculdade de Ciencias, Centro de Biodiversidade, Genomica Integrativa e Funcional (BioFIG), Campus de FCUL, Campo Grande, 1749-016 Lisboa (Portugal); Matos, Antonio Pedro [Servico de Anatomia Patologica, Hospital Curry Cabral, Lisboa (Portugal); Costa, Maria Clara, E-mail: mcorada@ualg.pt [Centro de Ciencias do Mar, Universidade do Algarve, FCT-DQF (edificio 8), Campus de Gambelas, 8005-139 Faro (Portugal)

2010-12-15

The mechanism of uranium (VI) removal by two anaerobic bacterial consortia, recovered from an uncontaminated site (consortium A) and other from an uranium mine (consortium U), was investigated. The highest efficiency of U (VI) removal by both consortia (97%) occurred at room temperature and at pH 7.2. Furthermore, it was found that U (VI) removal by consortium A occurred by enzymatic reduction and bioaccumulation, while the enzymatic process was the only mechanism involved in metal removal by consortium U. FTIR analysis suggested that after U (VI) reduction, U (IV) could be bound to carboxyl, phosphate and amide groups of bacterial cells. Phylogenetic analysis of 16S rRNA showed that community A was mainly composed by bacteria closely related to Sporotalea genus and Rhodocyclaceae family, while community U was mainly composed by bacteria related to Clostridium genus and Rhodocyclaceae family.

Mechanism of uranium (VI) removal by two anaerobic bacterial communities

International Nuclear Information System (INIS)

Martins, Monica; Faleiro, Maria Leonor; Costa, Ana M. Rosa da; Chaves, Sandra; Tenreiro, Rogerio; Matos, Antonio Pedro; Costa, Maria Clara

2010-01-01

The mechanism of uranium (VI) removal by two anaerobic bacterial consortia, recovered from an uncontaminated site (consortium A) and other from an uranium mine (consortium U), was investigated. The highest efficiency of U (VI) removal by both consortia (97%) occurred at room temperature and at pH 7.2. Furthermore, it was found that U (VI) removal by consortium A occurred by enzymatic reduction and bioaccumulation, while the enzymatic process was the only mechanism involved in metal removal by consortium U. FTIR analysis suggested that after U (VI) reduction, U (IV) could be bound to carboxyl, phosphate and amide groups of bacterial cells. Phylogenetic analysis of 16S rRNA showed that community A was mainly composed by bacteria closely related to Sporotalea genus and Rhodocyclaceae family, while community U was mainly composed by bacteria related to Clostridium genus and Rhodocyclaceae family.

Learning outcomes using video in supervision and peer feedback during clinical skills training

DEFF Research Database (Denmark)

Lauridsen, Henrik Hein; Toftgård, Rie Castella; Nørgaard, Cita

supervision of clinical skills (formative assessment). Demonstrations of these principles will be presented as video podcasts during the session. The learning outcomes of video supervision and peer-feedback were assessed in an online questionnaire survey. Results Results of the supervision showed large self......Objective New technology and learning principles were introduced in a clinical skills training laboratory (iLab). The intension was to move from apprenticeship to active learning principles including peer feedback and supervision using video. The objective of this study was to evaluate student...... learning outcomes in a manual skills training subject using video during feedback and supervision. Methods The iLab classroom was designed to fit four principles of teaching using video. Two of these principles were (a) group work using peer-feedback on videos produced by the students and, (b) video...

Cr(VI) occurrence and geochemistry in water from public-supply wells in California

Science.gov (United States)

Izbicki, John; Wright, Michael; Seymour, Whitney A.; McCleskey, R. Blaine; Fram, Miranda S.; Belitz, Kenneth; Esser, Bradley K.

2015-01-01

Hexavalent chromium, Cr(VI), in 918 wells sampled throughout California between 2004 and 2012 by the Groundwater Ambient Monitoring and Assessment-Priority Basin Project (GAMA-PBP) ranged from less than the study reporting limit of 1 microgram per liter (μg/L) to 32 μg/L. Statewide, Cr(VI) was reported in 31 percent of wells and equaled or exceeded the recently established (2014) California Maximum Contaminant Level (MCL) for Cr(VI) of 10 μg/L in 4 percent of wells. Cr(VI) data collected for regulatory purposes overestimated Cr(VI) occurrence compared to spatially-distributed GAMA-PBP data. Ninety percent of chromium was present as Cr(VI), which was detected more frequently and at higher concentrations in alkaline (pH ≥ 8), oxic water; and more frequently in agricultural and urban land uses compared to native land uses. Chemical, isotopic (tritium and carbon-14), and noble-gas data show high Cr(VI) in water from wells in alluvial aquifers in the southern California deserts result from long groundwater-residence times and geochemical reactions such as silicate weathering that increase pH, while oxic conditions persist. High Cr(VI) in water from wells in alluvial aquifers along the west-side of the Central Valley results from high-chromium in source rock eroded to form those aquifers, and areal recharge processes (including irrigation return) that can mobilize chromium from the unsaturated zone. Cr(VI) co-occurred with oxyanions having similar chemistry, including vanadium, selenium, and uranium. Cr(VI) was positively correlated with nitrate, consistent with increased concentrations in areas of agricultural land use and mobilization of chromium from the unsaturated zone by irrigation return.

Oxidation of ciprofloxacin and enrofloxacin by ferrate(VI): Products identification, and toxicity evaluation

International Nuclear Information System (INIS)

Yang, Bin; Kookana, Rai S.; Williams, Mike; Ying, Guang-Guo; Du, Jun; Doan, Hai; Kumar, Anupama

2016-01-01

Ferrate(VI) (Fe(VI)) has been known to react with emerging organic contaminants containing electron-rich organic moieties, such as phenols, anilines, olefins, reduced sulfur and deprotonated amines. Oxidation of fluoroquinolone antibiotics, ciprofloxacin (CIP) and enrofloxacin (ENR), by Fe(VI) were investigated for their reaction products and toxicity changes as well as biodegradability of these products. Ten products were identified for both CIP and ENR reactions with Fe(VI) using a high-resolution accurate-mass Orbitrap mass analyzer. Structural changes to the CIP and ENR molecule included dealkylation, formation of alcohols and amides in piperazine ring and oxygen transfer to the double bond in quinolone structure. An enamine formation mechanism was tentatively proposed to facilitate the interpretation of CIP and ENR oxidation pathways. Toxicity evaluation using Microbial Assay for toxicity Risk Assessment (MARA) bioassay indicated that Fe(VI) oxidation products of CIP and ENR contributed negligible antibacterial potency and Fe(VI) oxidation treatment can remove the residual toxicity of CIP and ENR impacted source waters. The Fe(VI) oxidation treatment resulted in formation of relatively more biodegradable products (based on in silico assessment) than their corresponding parent compounds. The results showed that Fe(VI) has a good potential to degrade fluoroquinolone antibiotics and their antimicrobial potency in natural waters.

Oxidation of ciprofloxacin and enrofloxacin by ferrate(VI): Products identification, and toxicity evaluation

Energy Technology Data Exchange (ETDEWEB)

Yang, Bin, E-mail: Bin.Yang@csiro.au [CSIRO Land and Water, Waite Campus, PMB 2, Glen Osmond, South Australia 5064 (Australia); Kookana, Rai S.; Williams, Mike [CSIRO Land and Water, Waite Campus, PMB 2, Glen Osmond, South Australia 5064 (Australia); Ying, Guang-Guo [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Du, Jun; Doan, Hai; Kumar, Anupama [CSIRO Land and Water, Waite Campus, PMB 2, Glen Osmond, South Australia 5064 (Australia)

2016-12-15

Ferrate(VI) (Fe(VI)) has been known to react with emerging organic contaminants containing electron-rich organic moieties, such as phenols, anilines, olefins, reduced sulfur and deprotonated amines. Oxidation of fluoroquinolone antibiotics, ciprofloxacin (CIP) and enrofloxacin (ENR), by Fe(VI) were investigated for their reaction products and toxicity changes as well as biodegradability of these products. Ten products were identified for both CIP and ENR reactions with Fe(VI) using a high-resolution accurate-mass Orbitrap mass analyzer. Structural changes to the CIP and ENR molecule included dealkylation, formation of alcohols and amides in piperazine ring and oxygen transfer to the double bond in quinolone structure. An enamine formation mechanism was tentatively proposed to facilitate the interpretation of CIP and ENR oxidation pathways. Toxicity evaluation using Microbial Assay for toxicity Risk Assessment (MARA) bioassay indicated that Fe(VI) oxidation products of CIP and ENR contributed negligible antibacterial potency and Fe(VI) oxidation treatment can remove the residual toxicity of CIP and ENR impacted source waters. The Fe(VI) oxidation treatment resulted in formation of relatively more biodegradable products (based on in silico assessment) than their corresponding parent compounds. The results showed that Fe(VI) has a good potential to degrade fluoroquinolone antibiotics and their antimicrobial potency in natural waters.

A Salmonella Typhimurium-Typhi genomic chimera: a model to study Vi polysaccharide capsule function in vivo.

Directory of Open Access Journals (Sweden)

Angela M Jansen

2011-07-01

Full Text Available The Vi capsular polysaccharide is a virulence-associated factor expressed by Salmonella enterica serotype Typhi but absent from virtually all other Salmonella serotypes. In order to study this determinant in vivo, we characterised a Vi-positive S. Typhimurium (C5.507 Vi(+, harbouring the Salmonella pathogenicity island (SPI-7, which encodes the Vi locus. S. Typhimurium C5.507 Vi(+ colonised and persisted in mice at similar levels compared to the parent strain, S. Typhimurium C5. However, the innate immune response to infection with C5.507 Vi(+ and SGB1, an isogenic derivative not expressing Vi, differed markedly. Infection with C5.507 Vi(+ resulted in a significant reduction in cellular trafficking of innate immune cells, including PMN and NK cells, compared to SGB1 Vi(- infected animals. C5.507 Vi(+ infection stimulated reduced numbers of TNF-α, MIP-2 and perforin producing cells compared to SGB1 Vi(-. The modulating effect associated with Vi was not observed in MyD88(-/- and was reduced in TLR4(-/- mice. The presence of the Vi capsule also correlated with induction of the anti-inflammatory cytokine IL-10 in vivo, a factor that impacted on chemotaxis and the activation of immune cells in vitro.

Uranium(VI) adsorption properties of a chelating resin containing polyamine-substituted methylphosphonic acid moiety

International Nuclear Information System (INIS)

Matsuda, Masaaki; Akiyoshi, Yoshirou

1991-01-01

Uranium(VI) adsorption and desorption properties of a chelating resin containing polyamine-substituted methylphosphonic acid moiety of 2.29 mmol/g-resin (APA) were examined. Uranium(VI) adsorption properties of several ion exchange resins and extractant agents which were known as excellent adsorbents for uranium(VI), were examined together for a comparison with those of APA. Uranium(VI) adsorption capacity of APA at the concentration of 100 mg·dm -3 -uranium(VI) in 100 g·dm -3 -H 2 SO 4 aq. soln., 190 g·dm -3 -H 3 PO 4 aq. soln. and uranium enriched sea water, was 0.2, 0.05 and 0.05 mmol·g -1 respectively. The adsorption capacity of APA for uranium(VI) in these solutions was larger than that of another adsorbents, except the adsorption of uranium(VI) in enriched sea water on ion exchange resin containing phosphoric acid moiety (adsorption capacity ; 0.2 mmol·g -1 ). Uranium(VI) adsorption rate on APA was high and the relation between treatment time (t : min) and uranium(VI) concentration (y : mg·dm -3 ) in 100 g·dm -3 H 2 SO 4 aq. soln. after treatment, was shown as following equation, y=20 0.048t+1.90 (0≤t≤30). The adsorbed uranium(VI) on APA was able to be eluted with a mixed aq. soln. of hydrogen peroxide and sodium hydroxide and also was able to be eluted with an aq. alkaline soln. dissolved reduction agents such as sodium sulfite and hydrazine. From these results, it was thought that uranium(VI) adsorbed on APA was eluted due to the reduction to uranium(VI) by these eluents. (author)

Group IB Organometallic Chemistry XXXIV: Thermal behavior and chemical reactivity of tetranuclear Me2N-substituted diarylpropenylcopper-copper anion (Vi2Cu4X2) and mixed diarylpropenyl/organocopper (Vi2Cu4R2) compounds

NARCIS (Netherlands)

Koten, G. van; Hoedt, R.W.M. ten; Noltes, J.G.

1980-01-01

Thermal decomposition of configurationally pure 1, 2-diarylpropenylcopper compounds Z-Vi{2}CU{4}Br{2} and Z-Vi{2}Cu{4}R{2} [Vi @? (2-Me{2}NC{6}H{4})C@?C(Me)-(C{6}H{4}Me-4), R @? 2-Me{2}NC{6}H{4} or 4-MeC{6}H{4}C@?C] predominantly results in the formation of ViH. In contrast, only dimers (ViVi) were

Oxidação de microcistinas-LR em águas pelo íon ferrato(VI Aqueous oxidation of microcystin-LR by ferrate(VI

Directory of Open Access Journals (Sweden)

Sérgio João de Luca

2010-03-01

Full Text Available Toxinas de cianobactérias têm se tornado um grave problema na produção segura de água para consumo humano e animal. Técnicas convencionais de tratamento falham em atingir padrões de potabilidade. O ferrato(VI de potássio, um composto oxidante e coagulante, mostra potencialidade no tratamento de águas contaminadas. Neste trabalho, são apresentados resultados da oxidação pelo ferrato(VI de uma toxina gerada por cianobactérias, a microcistina-LR. Ensaios de cinética de oxidação e de teste de jarros mostram um valor médio de 0,012 min-1 para a constante de taxa de reação de pseudoprimeira ordem, para concentrações de MC-LR de 100 a 200 µg.L-1 na água bruta. Dosagens de 1,6 a 5,0 mg.L-1 de ferrato(VI sugerem o atendimento ao padrão de potabilidade para microcistinas, mostrando que o oxidante poderá ser empregado como coadjuvante no tratamento de água.Algae toxins are becoming a severe problem in the water treatment industry, especially for human and animal consumption. Traditional treatment processes have failed in complying with water supply standards. Potassium ferrate(VI is a powerful oxidant, disinfectant and, also, a coagulant. In this paper, the results of microcystin-LR oxidation by ferrate(VI ion are presented. Kinetic and jar tests showed a average value of 0,012 min-1 for the pseudo first order reaction rate constant, for 100 and 200 µg.L-1 concentration of MC-LR. Ferrate(VI dosages between 1.6 and 5.0 mg.L-1 suggest that water supply standards for MC-LR can be reached, which means that the oxidant may be employed as coadjuvant in water treatment.

Retention of uranium(VI) by laumontite, a fracture-filling material of granite

International Nuclear Information System (INIS)

Baik, M.H.; Lee, S.Y.; Shon, W.J.

2009-01-01

Retention of U(VI) by laumontite, a fracture-filling material of granite as investigated by conducting dynamic and batch sorption experiments in a love-box using a granite core with a natural fracture. The hydrodynamic properties of the granite core were obtained from the elution curve of a on-sorbing tracer, Br - . The elution curve of U(VI) showed a similar behavior to Br - . This reveals that the retention of U(VI) by the fracture-filling material was not significant when migrating through the fracture at a given condition. From the dynamic sorption experiment, the retardation factor R a and the distribution coefficient K a of U(VI) were obtained as about 2.9 and 0.16 cm, respectively. The distribution coefficient K d ) of U(VI) onto laumontite obtained by conducting a batch sorption experiment resulted in a small value of 2.3±0.5 mL/g. This low K d value greed with the result of the dynamic sorption experiment. For the distribution of uranium on the granite surface investigated by an X-ray image mapping, the fracture region filled with laumontite showed a relatively lower content of uranium compared to the surrounding granite surface. Thus, the low retention of U(VI) by the fracture-filling material can be explained by following two mechanisms. One is that U(VI) exists as anionic uranyl hydroxides or uranyl carbonates at a given groundwater condition and the other is the remarkably low sorption capacity of the laumontite for U(VI). author)

Fluorescent silver nanoclusters for ultrasensitive determination of chromium(VI) in aqueous solution

International Nuclear Information System (INIS)

Zhang, Jian Rong; Zeng, Ai Lian; Luo, Hong Qun; Li, Nian Bing

2016-01-01

Highlights: • Fluorescent Ag nanoclusters were first applied to Cr(VI) detection. • The proposed method is simple, rapid, and environmentally friendly. • The sensor shows a wide linear range, low detection limit, and good selectivity. • The system can also be used for the indirect assay of total chromium and Cr(III). • The analyses in real water samples are satisfactory. - Abstract: In this work, a simple and sensitive Cr(VI) sensor is proposed based on fluorescent polyethyleneimine-stabilized Ag nanoclusters, which allows the determination over a wide concentration range of 0.1 nM–3.0 μM and with a detection limit as low as 0.04 nΜ and a good selectivity. The quenching mechanism was discussed in terms of the absorption and fluorescence spectra, suggesting that Cr(VI) is connected to Ag nanoclusters by hydrogen bond between the oxygen atom at the vertex of tetrahedron structure of Cr(VI) and the amino nitrogen of polyethyleneimine that surrounded Ag nanoclusters and electron transfer from Ag nanoclusters to highly electron-deficient Cr(VI) results in fluorescence quenching. Despite the failure to quench the fluorescence efficiently, Cr(III) can also be measured using the proposed Ag nanoclusters by being oxidized to Cr(VI) in alkaline solution (pH ∼9) containing H 2 O 2 . Therefore, our approach could be used to detect Cr(VI), Cr(III) and the total chromium level in aqueous solution. In addition, Cr(VI) analysis in real water samples were satisfactory, indicating this method could be practically promising for chromium measurements.

Effect of Salicylic and Picolinic Acids on the Adsorption of U(VI) onto Oxides

International Nuclear Information System (INIS)

Park, Kyoung Kyun; Jung, Euo Chang; Cho, Hye Ryun; Song, Kyu Seok

2009-01-01

The effect of organic acids on the adsorption of U(VI) onto oxide surfaces (TiO 2 (anatase), SiO 2 (amorphous) and Al 2 O-3(amorphous)) has been investigated. Two different organic acids, salicylic and picolinic acids, were used. Changes of adsorption ratio of U(VI), which depend on the existence of organic acids in a sample, were measured as a function of pH. Quantities of adsorbed organic acids, which depend on the existence of U(VI) in a sample, were also measured as a function of pH. It is confirmed that the soluble complex formation of U(VI) with organic acids can deteriorate the adsorption of U(VI) onto TiO 2 surface. It is noteworthy that salicylic acid does not affect the adsorption of U(VI) onto SiO 2 surface, however, picolinic acid enhances the adsorption of U(VI) onto SiO 2 surface. The latter effect can be understood by considering the formation of a ternary surface complex on SiO 2 surface, which was confirmed by the co-adsorption of picolinic acid with U(VI) and the change in a fluorescence spectra of U(VI) on surface, In the case of Al 2 O-3, organic acids themselves were largely adsorbed onto a surface without deteriorating the adsorption of U(VI). This would support the possibility of a ternary surface complex formation on the Al 2 O-3 surface, and an additional spectroscopic study is required.

Role of paramagnetic chromium in chromium(VI)-induced damage in cultured mammalian cells.

OpenAIRE

Sugiyama, M

1994-01-01

Chromium(VI) compounds are known to be potent toxic and carcinogenic agents. Because chromium(VI) is easily taken up by cells and is subsequently reduced to chromium(III), the formation of paramagnetic chromium such as chromium(V) and chromium(III) is believed to play a role in the adverse biological effects of chromium(VI) compounds. The present report, uses electron spin resonance (ESR) spectroscopy; the importance of the role of paramagnetic chromium in chromium(VI)-induced damage in intac...

myTIPreport and Training for Independent Practice: A Tool for Real-Time Workplace Feedback for Milestones and Procedural Skills.

Science.gov (United States)

Connolly, AnnaMarie; Goepfert, Alice; Blanchard, Anita; Buys, Elizabeth; Donnellan, Nicole; Amundsen, Cindy L; Galvin, Shelley L; Kenton, Kimberly

2018-02-01

Few tools currently exist for effective, accessible delivery of real-time, workplace feedback in the clinical setting. We developed and implemented a real-time, web-based tool for performance-based feedback in the clinical environment. The tool (myTIPreport) was designed for performance-based feedback to learners on the Accreditation Council for Graduate Medical Education (ACGME) Milestones and procedural skills. "TIP" stands for "Training for Independent Practice." We implemented myTIPreport in obstetrics and gynecology (Ob-Gyn) and female pelvic medicine and reconstructive surgery (FPMRS) programs between November 2014 and May 2015. Residents, fellows, teachers, and program directors completed preimplementation and postimplementation surveys on their perceptions of feedback. Preimplementation surveys were completed by 656 participants of a total of 980 learners and teachers in 19 programs (12 Ob-Gyn and 7 FPMRS). This represented 72% (273 of 378) of learners and 64% (383 of 602) of teachers. Seventy percent of participants (381 of 546) reported having their own individual processes for real-time feedback; the majority (79%, 340 of 430) described these processes as informal discussions . Over 6 months, one-third of teachers and two-thirds of learners used the myTIPreport tool a total of 4311 times. Milestone feedback was recorded 944 times, and procedural feedback was recorded 3367 times. Feedback addressed all ACGME Milestones and procedures programmed into myTIPreport. Most program directors reported that tool implementation was successful. The majority of learners successfully received workplace feedback using myTIPreport. This web-based tool, incorporating procedures and ACGME Milestones, may be an important transition from other feedback formats.

Bayesian feedback versus Markovian feedback in a two-level atom

International Nuclear Information System (INIS)

Wiseman, H.M.; Mancini, Stefano; Wang Jin

2002-01-01

We compare two different approaches to the control of the dynamics of a continuously monitored open quantum system. The first is Markovian feedback, as introduced in quantum optics by Wiseman and Milburn [Phys. Rev. Lett. 70, 548 (1993)]. The second is feedback based on an estimate of the system state, developed recently by Doherty and Jacobs [Phys. Rev. A 60, 2700 (1999)]. Here we choose to call it, for brevity, Bayesian feedback. For systems with nonlinear dynamics, we expect these two methods of feedback control to give markedly different results. The simplest possible nonlinear system is a driven and damped two-level atom, so we choose this as our model system. The monitoring is taken to be homodyne detection of the atomic fluorescence, and the control is by modulating the driving. The aim of the feedback in both cases is to stabilize the internal state of the atom as close as possible to an arbitrarily chosen pure state, in the presence of inefficient detection and other forms of decoherence. Our results (obtained without recourse to stochastic simulations) prove that Bayesian feedback is never inferior, and is usually superior, to Markovian feedback. However, it would be far more difficult to implement than Markovian feedback and it loses its superiority when obvious simplifying approximations are made. It is thus not clear which form of feedback would be better in the face of inevitable experimental imperfections

Interpreting Feedback: A Discourse Analysis of Teacher Feedback and Student Identity

Science.gov (United States)

Torres, J. T.; Anguiano, Carlos J.

2016-01-01

Feedback has typically been studied as a means of improving academic performance. Few studies inquire into the processes by which feedback shapes student identity. The authors carry out a discourse analysis of written comments to explore how feedback is discursively constructed by both teachers and students. Analysis of written feedback,…

Biased Brownian motion mechanism for processivity and directionality of single-headed myosin-VI.

Science.gov (United States)

Iwaki, Mitsuhiro; Iwane, Atsuko Hikikoshi; Ikebe, Mitsuo; Yanagida, Toshio

2008-01-01

Conventional form to function as a vesicle transporter is not a 'single molecule' but a coordinated 'two molecules'. The coordinated two molecules make it complicated to reveal its mechanism. To overcome the difficulty, we adopted a single-headed myosin-VI as a model protein. Myosin-VI is an intracellular vesicle and organelle transporter that moves along actin filaments in a direction opposite to most other known myosin classes. The myosin-VI was expected to form a dimer to move processively along actin filaments with a hand-over-hand mechanism like other myosin organelle transporters. However, wild-type myosin-VI was demonstrated to be monomer and single-headed, casting doubt on its processivity. Using single molecule techniques, we show that green fluorescent protein (GFP)-fused single-headed myosin-VI does not move processively. However, when coupled to a 200 nm polystyrene bead (comparable to an intracellular vesicle in size) at a ratio of one head per bead, single-headed myosin-VI moves processively with large (40 nm) steps. Furthermore, we found that a single-headed myosin-VI-bead complex moved more processively in a high-viscous solution (40-fold higher than water) similar to cellular environment. Because diffusion of the bead is 60-fold slower than myosin-VI heads alone in water, we propose a model in which the bead acts as a diffusional anchor for the myosin-VI, enhancing the head's rebinding following detachment and supporting processive movement of the bead-monomer complex. This investigation will help us understand how molecular motors utilize Brownian motion in cells.

Molasses as an efficient low-cost carbon source for biological Cr(VI) removal

Energy Technology Data Exchange (ETDEWEB)

Michailides, Michail K. [Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio (Greece); Tekerlekopoulou, Athanasia G., E-mail: atekerle@upatras.gr [Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio (Greece); Akratos, Christos S.; Coles, Sandra [Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio (Greece); Pavlou, Stavros [Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Stadiou Str., Platani, P.O. Box 1414, GR-26504 Patras (Greece); Department of Chemical Engineering, University of Patras, GR-26504 Patras (Greece); Vayenas, Dimitrios V. [Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio (Greece); Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Stadiou Str., Platani, P.O. Box 1414, GR-26504 Patras (Greece)

2015-01-08

Highlights: • Suspended and attached growth reactors were examined for Cr(VI) bio-reduction. • Molasses was proved an efficient and very low cost carbon source. • Molasses was more efficient than sugar in enhancing Cr(VI) reduction. • SBR with recirculation was the most proper operating mode. - Abstract: In the present study, indigenous microorganisms from industrial sludge were used to reduce the activity of Cr(VI). Molasses, a by-product of sugar processing, was selected as the carbon source (instead of sugar used in a previous work) as it is a low-cost energy source for bioprocesses. Initially, experiments were carried out in suspended growth batch reactors for Cr(VI) concentrations of 1.5–110 mg/L. The time required for complete Cr(VI) reduction increased with initial Cr(VI) concentration. Initial molasses concentration was also found to influence the Cr(VI) reduction rate. The optimal concentration for all initial Cr(VI) concentrations tested was 0.8 gC/L. Experiments were also carried out in packed-bed reactors. Three different operating modes were used to investigate the optimal performance and efficiency of the filter, i.e. batch, continuous and SBR with recirculation. The latter mode with a recirculation rate of 0.5 L/min lead to significantly high Cr(VI) reduction rates (up to 135 g/m{sup 2} d). The results of this work were compared with those of a similar work using sugar as the carbon source and indicate that molasses could prove a feasible technological solution to a serious environmental problem.

Kinetic study of time-dependent fixation of U{sup VI} on biochar

Energy Technology Data Exchange (ETDEWEB)

Ashry, A. [Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, Leicestershire LE12 5RD (United Kingdom); Radiation Protection Department, Nuclear Research Centre, Egyptian Atomic Energy Authority, Cairo (Egypt); Bailey, E.H., E-mail: liz.bailey@nottingham.ac.uk [Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, Leicestershire LE12 5RD (United Kingdom); Chenery, S.R.N. [British Geological Survey, Nicker Hill, Keyworth, Nottingham NG12 5GG (United Kingdom); Young, S.D. [Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, Leicestershire LE12 5RD (United Kingdom)

2016-12-15

Biochar, a by-product from the production of biofuel and syngas by gasification, was tested as a material for adsorption and fixation of U{sup VI} from aqueous solutions. A batch experiment was conducted to study the factors that influence the adsorption and time-dependent fixation on biochar at 20 °C, including pH, initial concentration of U{sup VI} and contact time. Uranium (U{sup VI}) adsorption was highly dependent on pH but adsorption on biochar was high over a wide range of pH values, from 4.5 to 9.0, and adsorption strength was time-dependent over several days. The experimental data for pH > 7 were most effectively modelled using a Freundlich adsorption isotherm coupled to a reversible first order kinetic equation to describe the time-dependent fixation of U{sup VI} within the biochar structure. Desorption experiments showed that U{sup VI} was only sparingly desorbable from the biochar with time and isotopic dilution with {sup 233}U{sup VI} confirmed the low, or time-dependent, lability of adsorbed {sup 238}U{sup VI}. Below pH 7 the adsorption isotherm trend suggested precipitation, rather than true adsorption, may occur. However, across all pH values (4.5-9) measured saturation indices suggested precipitation was possible: autunite below pH 6.5 and either swartzite, liebigite or bayleyite above pH 6.5.

Raman spectrometric determination of Pu(VI) and Pu(V) in nitric acid solutions

International Nuclear Information System (INIS)

Gantner, E.; Freudenberger, M.; Steinert, D.; Ache, H.J.

1987-03-01

The determination of Pu(VI) in nitric acid solutions by spontaneous Laser Raman Spectrometry (LRS) was investigated and a calibration curve was established using U(VI) as internal standard. In addition, the concentrations of Pu(VI) and Pu(V) as a function of time were measured by this method in Pu(VI) solutions of different acidity containing H 2 O 2 as the reducing agent. In solutions which are intensely coloured by the presence of Ru(NO) complexes Pu(VI) can also be determined by LRS using a Kr + laser as excitation source. In future experiments, the study of the Pu(IV)-interaction with Ru using LRS and spectrophotometry as analytical techniques is therefore intended. (orig.) [de

28 CFR 42.405 - Public dissemination of title VI information.

Science.gov (United States)

2010-07-01

... Federally Assisted Programs § 42.405 Public dissemination of title VI information. (a) Federal agencies... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Public dissemination of title VI information. 42.405 Section 42.405 Judicial Administration DEPARTMENT OF JUSTICE NONDISCRIMINATION; EQUAL...

Optimizing personalized normative feedback: the use of gender-specific referents.

Science.gov (United States)

Lewis, Melissa A; Neighbors, Clayton

2007-03-01

Many brief interventions include personalized normative feedback (PNF) using gender-specific or gender-neutral referents. Several theories suggest that information pertaining to more socially proximal referents should have greater influence on one's behavior compared with more socially distal referents. The current research evaluated whether gender specificity of the normative referent employed in PNF related to intervention efficacy. Following baseline assessment, 185 college students (45.2% women) were randomly assigned to one of three intervention conditions: gender-specific feedback, gender-neutral feedback, or assessment-only control. Immediately after completing measures of perceived norms, alcohol consumption, and gender identity, participants in the gender-neutral and gender-specific intervention conditions were provided with computerized information detailing their own drinking behavior, their perceptions of student drinking, and actual student drinking. After a 1-month follow-up, the results indicated that normative feedback was effective in changing perceived norms and reducing alcohol consumption for both intervention groups for women and men. The results provide support, however, for changes in perceived gender-specific norms as a mediator of the effects of normative feedback on reduced drinking behavior for women only. Additionally, gender-specific feedback was found to be more effective for women higher in gender identity, relative to the gender-neutral feedback. A post-assessment follow-up telephone survey administered to assess potential demand characteristics corroborated the intervention effects. Results extend previous research documenting efficacy of computer delivered PNF. Gender specificity and gender identity appear to be important elements to consider for PNF intervention efficacy for women.

ENDF-201: ENDF/B-VI summary documentation

International Nuclear Information System (INIS)

Rose, P.F.

1991-10-01

Responsibility for oversight of the ENDF/B Evaluated Nuclear Data file lies with the Cross Section Evaluation Working Group (CSEWG), which is comprised of representatives from various governmental and industrial laboratories in the United States. Individual evaluations are provided by scientists at several US laboratories, including significant contributions by scientists from all over the world. In addition, ENDF/B-VI includes for the first time complete evaluations for three materials that were provided from laboratories outside the US. All data are checked and reviewed by CSEWG, and the data file is maintained and issued by the National Nuclear Data Center at Brookhaven National Laboratory. The previous version of the library, ENDF/B-V, was issued in 1979, and two revisions to the data file were provided in subsequent years, the latest occurring in 1981. A total of 75 new or extensively modified neutron sublibrary evaluations are included in ENDF/B-VI, and are summarized in this document. One incident proton sublibrary is described for Fe 56 . The remaining evaluations in ENDF/B-VI have been carried over from earlier versions of ENDF, and have been updated to reflect the new formats. The release of ENDF/B-VI was carried out between January and June of 1990, with groups of materials being released on ''tapes.'' Table 1 is an index to the evaluation summaries, and includes the material identification or MAT number, the responsible laboratory, and the ''tape'' number. These evaluations have been released without restrictions on their distribution or use

ENDF-201: ENDF/B-VI summary documentation

Energy Technology Data Exchange (ETDEWEB)

Rose, P.F. (comp.)

1991-10-01

Responsibility for oversight of the ENDF/B Evaluated Nuclear Data file lies with the Cross Section Evaluation Working Group (CSEWG), which is comprised of representatives from various governmental and industrial laboratories in the United States. Individual evaluations are provided by scientists at several US laboratories, including significant contributions by scientists from all over the world. In addition, ENDF/B-VI includes for the first time complete evaluations for three materials that were provided from laboratories outside the US. All data are checked and reviewed by CSEWG, and the data file is maintained and issued by the National Nuclear Data Center at Brookhaven National Laboratory. The previous version of the library, ENDF/B-V, was issued in 1979, and two revisions to the data file were provided in subsequent years, the latest occurring in 1981. A total of 75 new or extensively modified neutron sublibrary evaluations are included in ENDF/B-VI, and are summarized in this document. One incident proton sublibrary is described for Fe{sup 56}. The remaining evaluations in ENDF/B-VI have been carried over from earlier versions of ENDF, and have been updated to reflect the new formats. The release of ENDF/B-VI was carried out between January and June of 1990, with groups of materials being released on tapes.'' Table 1 is an index to the evaluation summaries, and includes the material identification or MAT number, the responsible laboratory, and the tape'' number. These evaluations have been released without restrictions on their distribution or use.

ENDF-201: ENDF/B-VI summary documentation

Energy Technology Data Exchange (ETDEWEB)

Rose, P.F. [comp.

1991-10-01

Responsibility for oversight of the ENDF/B Evaluated Nuclear Data file lies with the Cross Section Evaluation Working Group (CSEWG), which is comprised of representatives from various governmental and industrial laboratories in the United States. Individual evaluations are provided by scientists at several US laboratories, including significant contributions by scientists from all over the world. In addition, ENDF/B-VI includes for the first time complete evaluations for three materials that were provided from laboratories outside the US. All data are checked and reviewed by CSEWG, and the data file is maintained and issued by the National Nuclear Data Center at Brookhaven National Laboratory. The previous version of the library, ENDF/B-V, was issued in 1979, and two revisions to the data file were provided in subsequent years, the latest occurring in 1981. A total of 75 new or extensively modified neutron sublibrary evaluations are included in ENDF/B-VI, and are summarized in this document. One incident proton sublibrary is described for Fe{sup 56}. The remaining evaluations in ENDF/B-VI have been carried over from earlier versions of ENDF, and have been updated to reflect the new formats. The release of ENDF/B-VI was carried out between January and June of 1990, with groups of materials being released on ``tapes.`` Table 1 is an index to the evaluation summaries, and includes the material identification or MAT number, the responsible laboratory, and the ``tape`` number. These evaluations have been released without restrictions on their distribution or use.

Biological Cr(VI) removal using bio-filters and constructed wetlands.

Science.gov (United States)

Michailides, Michail K; Sultana, Mar-Yam; Tekerlekopoulou, Athanasia G; Akratos, Christos S; Vayenas, Dimitrios V

2013-01-01

The bioreduction of hexavalent chromium from aqueous solution was carried out using suspended growth and packed-bed reactors under a draw-fill operating mode, and horizontal subsurface constructed wetlands. Reactors were inoculated with industrial sludge from the Hellenic Aerospace Industry using sugar as substrate. In the suspended growth reactors, the maximum Cr(VI) reduction rate (about 2 mg/L h) was achieved for an initial concentration of 12.85 mg/L, while in the attached growth reactors, a similar reduction rate was achieved even with high initial concentrations (109 mg/L), thus confirming the advantage of these systems. Two horizontal subsurface constructed wetlands (CWs) pilot-scale units were also built and operated. The units contained fine gravel. One unit was planted with common reeds and one was kept unplanted. The mean influent concentrations of Cr(VI) were 5.61 and 5.47 mg/L for the planted and unplanted units, respectively. The performance of the planted CW units was very effective as mean Cr(VI) removal efficiency was 85% and efficiency maximum reached 100%. On the contrary, the unplanted CW achieved very low Cr(VI) removal with a mean value of 26%. Both attached growth reactors and CWs proved efficient and viable means for Cr(VI) reduction.

VI Tallinna arhitektuuritriennaal / Leonhard Lapin

Index Scriptorium Estoniae

Lapin, Leonhard, 1947-

2005-01-01

15.-17. IX Tallinnas Niguliste kirikus toimuval VI Tallinna arhitektuuritriennaalil esinevad inglise arhitektuurikriitik Peter Davey, šveitsi arhitekt Peter Zumthor, soome arhitekt Juha Leviskä, eesti arhitekt Vilen Künnapu, eesti kunstiajaloolane Juhan Maiste jt. Külastatakse KUMU, tutvutab autor Pekka Vapaavuori

Extraction of uranium (VI) sulphate complexes by Adogen amines

Energy Technology Data Exchange (ETDEWEB)

Elyamani, I S; Abd Elmessieh, E N [Nuclear chemistry department, hot laboratories center, atomic energy authority, Cairo, (Egypt)

1995-10-01

The distribution of U(VI) between aqueous H{sub 2} So{sub 4} solutions and organic phases of adogen-368 has been described. The dependence of extraction on acidity, diluent type, metal and extractant concentrations was investigated. The possible extraction mechanism is discussed in the light of results obtained. The separation of U(VI) from rare earths is suggested. 5 figs., 1 tab.

Reduction of chromium (VI by the indirect action of Thiobacillus thioparus

Directory of Open Access Journals (Sweden)

E. Donati

2003-03-01

Full Text Available The microbial reduction of chromium(VI to chromium(III has been one of the most widely studied forms of metal bioremediation. Recently, we have found that Thiobacillus ferrooxidans and Thiobacillus thiooxidans, growing on elemental sulphur, can indirectly promote chromium(VI reduction by producing reducing agents such as sulphite and thiosulphate, which abiotically reduce chromium(VI. Those species of Thiobacillus are acidophilic bacteria which grow optimally at pH values lower than 4. However, most of those reducing agents are stabilised at higher pH values. Thus, the present paper reports on the ability to reduce chromium(VI using another specie of Thiobacilli, Thiobacillus thioparus, which is able to grow at pH close to 7.0. T. thioparus cultures were carried out in a fermentation vessel containing medium and sulphur as the sole energy source and maintained at 30ºC and 400 rpm. The pH was adjusted to 6.0, 7.0 or 8.0 and maintained with the automatic addition of KOH. Our results show high chromium (VI reduction values (close to 100% at the end of bacterial growth at the three pH values. The results of these experiments are very promising for development of a microbiological process to be used in the detoxification of chromium(VI-polluted effluents.

CHROMIUM(VI REDUCTION BY A MIXED CULTURE OF SULFATE REDUCING BACTERIA DEVELOPED IN COLUMN REACTOR

Directory of Open Access Journals (Sweden)

Cynthia Henny

2008-03-01

Full Text Available A lactate enriched mixed sulfate reducing bacteria (SRB culture was examined for the reduction of Cr(VI in a continuous flow system. The influent was mineral salts media added with lactate and sulfate with amounts of 8 and 6 mM respectively as electron donor and electron acceptor. The SRB culture was allowed to stabilize in the column before adding the Cr(VI to the influent. Chromium and sulfate reduction and lactate oxidation were examined by measuring the concentrations of Cr(Vl, sulfate and lactate in the influent and the effluent over time. The experiment was discontinued when Cr(VI concentration in the effiuent was breakthrough. In the absence of Cr(VI, sulfate was not completely reduced in the column, although lactate was completely oxidized and acetate as an intermediate product was not often detected. Almost all of Cr(VI loaded was reduced in the column seeded with the SRB culture at influent Cr(VI concentrations of 192,385 and769 mM. There was no significant Cr(VI loss in the control column, indicating that Cr(VI removal was due to the reduction of Cr(VI to Cr (lll by the SRB culture. The instantaneous Cr(VI removal decreased to a minimum of 32%, 24 days after the influent Cr(VI concentration was increased to 1540 mM, ancl sulfate removal efficiency decreased to a minimum of 17%. The SRB population in the column decreased 100 days after C(VI was added to the column. The total mass of Cr(VI reduced was approximately 878 mmol out of 881 mmol of Cr(Vl loaded in 116 days. The results clearly show that our developed SRB culture could reduced Cr(Vl considerably.

Studies on the kinetics of uranium (VI) electro-reduction and reextraction: Pt. 2

International Nuclear Information System (INIS)

Tong Jihong; Ma Xuquan; Tai Derong; Sun Shiren

1992-01-01

The kinetics of U(VI) reextraction and U(IV) extraction in the process of U(VI) electro-reduction with the system of HNO 3 -N 2 H 5 NO 3 (H 2 O)/UO 2 (NO 3 ) 2 -HNO 3 (30% TBP-OK) is investigated with a constant interfacial area cell (Lewis cell) with cathode and anode in it. According to the experimental results and data processing, the apparent activation energy of the U(VI) reextraction process is 36.02 kJ/nol. The U(VI) reextraction rate increases when the stirring speed of two phases increases. This process is mainly diffusion controlled. For the U(VI) extraction process, the apparent activation energy is 21.13 kJ/mol. The U(IV) extraction rate also increases when the stirring speed of two phases increases. This process is mainly diffusion controlled. The lower the potential of cathode is, the higher the rates of U(VI) reextraction and U(IV) extraction are

Kinetics and Products of Chromium(VI) Reduction by Iron(II/III)-Bearing Clay Minerals.

Science.gov (United States)

Joe-Wong, Claresta; Brown, Gordon E; Maher, Kate

2017-09-05

Hexavalent chromium is a water-soluble pollutant, the mobility of which can be controlled by reduction of Cr(VI) to less soluble, environmentally benign Cr(III). Iron(II/III)-bearing clay minerals are widespread potential reductants of Cr(VI), but the kinetics and pathways of Cr(VI) reduction by such clay minerals are poorly understood. We reacted aqueous Cr(VI) with two abiotically reduced clay minerals: an Fe-poor montmorillonite and an Fe-rich nontronite. The effects of ionic strength, pH, total Fe content, and the fraction of reduced structural Fe(II) [Fe(II)/Fe(total)] were examined. The last variable had the largest effect on Cr(VI) reduction kinetics: for both clay minerals, the rate constant of Cr(VI) reduction varies by more than 3 orders of magnitude with Fe(II)/Fe(total) and is described by a linear free energy relationship. Under all conditions examined, Cr and Fe K-edge X-ray absorption near-edge structure spectra show that the main Cr-bearing product is a Cr(III)-hydroxide and that Fe remains in the clay structure after reacting with Cr(VI). This study helps to quantify our understanding of the kinetics of Cr(VI) reduction by Fe(II/III)-bearing clay minerals and may improve predictions of Cr(VI) behavior in subsurface environments.

Polyaniline (PANI) modified bentonite by plasma technique for U(VI) removal from aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Liu, Xinghao [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Intelligent Manufacturing Technology Research Institute, Hefei University of Technology, Hefei 230088 (China); Cheng, Cheng [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Xiao, Chengjian, E-mail: xiaocj@caep.cn [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Shao, Dadong, E-mail: shaodadong@126.com [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Xu, Zimu, E-mail: xzm@mail.ustc.edu.cn [Intelligent Manufacturing Technology Research Institute, Hefei University of Technology, Hefei 230088 (China); Wang, Jiaquan; Hu, Shuheng [Intelligent Manufacturing Technology Research Institute, Hefei University of Technology, Hefei 230088 (China); Li, Xiaolong; Wang, Weijuan [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China)

2017-07-31

Highlights: • PANI/bentonie can be synthesized by simple plasma technique. • PANI/bentonie has an excellent adsorption capacity for trace uranium in solution. • U(VI) adsorption on PANI/bentonite is a spontaneous and endothermic process. - Abstract: Polyaniline (PANI) modified bentonite (PANI/bentonie) was synthesized by plasma induced polymerization of aniline on bentonite surface, and applied to uptake of uranium(VI) ions from aqueous solution. The as-synthesized PANI/bentonie was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). Batch adsorption technique was utilized to investigate the adsorption of U(VI) on bentonite and PANI/bentonite. The adsorption of U(VI) (10 mg/L) on PANI/bentonite surface is fairly depend on solution pH, ionic strength, and temperature in solution. The modified PANI on PANI/bentonite surface significantly enhances its adsorption capability for U(VI). The presence of humic acid (HA) can sound enhance U(VI) adsorption on PANI/bentonite at pH < 6.5 because of the strong complexation, and inhibits U(VI) adsorption at pH > 6.5. According to the thermodynamic parameters, the adsorption of U(VI) on PANI/bentonite surface is a spontaneous and endothermic process. The results highlight the application of PANI/bentonite composites as candidate material for the uptake of trace U(VI) from aqueous solution.

Study on Cr(VI) Leaching from Cement and Cement Composites

Science.gov (United States)

Palascakova, Lenka; Kanuchova, Maria

2018-01-01

This paper reports an experimental study on hexavalent chromium leaching from cement samples and cement composites containing silica fume and zeolite additions that were subjected to various leaching agents. The water-soluble Cr(VI) concentrations in cements ranged from 0.2 to 3.2 mg/kg and represented only 1.8% of the total chromium content. The presence of chromium compounds with both chromium oxidation states of III and VI was detected in the cement samples by X-ray photoelectron spectroscopy (XPS). Leaching tests were performed in a Britton-Robinson buffer to simulate natural conditions and showed increased dissolution of Cr(VI) up to 6 mg/kg. The highest amount of leached hexavalent chromium was detected after leaching in HCl. The findings revealed that the leaching of chromium from cements was higher by 55–80% than that from the cement composites. A minimum concentration was observed for all cement samples when studying the relationship between the soluble Cr(VI) and the cement storage time. PMID:29690550

Remediation of U(VI)-contaminated water using zero-valent iron

International Nuclear Information System (INIS)

Abdelouas, A.; Gong, W.; Lutze, W.; Nuttall, E.

1999-01-01

We investigated the possibility of U(VI) reduction by zero-valent iron (Fe 0 ). We conducted batch experiments with granular iron and solutions containing 0.25 and 9.3 mg L -1 U(VI) at 24 deg C. The solution pH ranges between 2 and 9. In all experiments uranium removal was complete within several hours to several days regardless of the pH value. The reduced uranium precipitated as poorly crystallized hydrated uraninite, UO 2 .nH 2 O. The reduction of U(VI) to U(IV) by Fe 0 was found to be the principal mechanism of U removal from the solution. Other mechanisms such as U(VI) sorption on the newly formed Fe(III) hydroxides are insignificant. These results show that zero-valent iron can be used to remedy U-contaminated waters from uranium mines and mill tailings sites, the pH of which usually ranges between 2 and 9. (authors)

A critical review of ferrate(VI)-based remediation of soil and groundwater.

Science.gov (United States)

Rai, Prabhat Kumar; Lee, Jechan; Kailasa, Suresh Kumar; Kwon, Eilhann E; Tsang, Yiu Fai; Ok, Yong Sik; Kim, Ki-Hyun

2018-01-01

Over the past few decades, diverse chemicals and materials such as mono- and bimetallic nanoparticles, metal oxides, and zeolites have been used for soil and groundwater remediation. Ferrate (Fe VI O 4 2- ) has been widely employed due to its high-valent iron (VI) oxo compound with high oxidation/reduction potentials. Ferrate has received attention for wide environmental applications including water purification and sewage sludge treatment. Ferrate provides great potential for diverse environmental applications without any environmental problems. Therefore, this paper provides comprehensive information on the recent progress on the use of (Fe VI O 4 2- ) as a green material for use in sustainable treatment processes, especially for soil and water remediation. We reviewed diverse synthesis recipes for ferrates (Fe VI O 4 2- ) and their associated physicochemical properties as oxidants, coagulants, and disinfectants for the elimination of a diverse range of chemical and biological species from water/wastewater samples. A summary of the eco-sustainable performance of ferrate(VI) in water remediation is also provided and the future of ferrate(VI) is discussed in this review. Copyright © 2017 Elsevier Inc. All rights reserved.

Carbon-13 NMR characterization of actinyl(VI) carbonate complexes in aqueous solution

International Nuclear Information System (INIS)

Clark, D.L.; Hobart, D.E.; Palmer, P.D.; Sullivan, J.C.; Stout, B.E.

1992-01-01

The uranyl(VI) carbonate system has been re-examined using 13 C NMR of 99.9% 13 C-enriched U VI O 2 ( 13 CO 3 ) 3 4- in millimolar concentrations. By careful control of carbonate ion concentration, we have confirmed the existence of the trimer, and observed dynamic equilibrium between the monomer and the timer. In addition, the ligand exchange reaction between free and coordinated carbonate on Pu VI O 2 ( 13 CO 3 ) 3 4- and Am VI O 2 ( 13 CO 3 ) 3 4- systems has been examined by variable temperature 13 C NMR line-broadening techniques 13 C NMR line-broadening techniques. A modified Carr-Purcell-Meiboom-Gill NMR pulse sequence was written to allow for experimental determination of ligand exchange parameters for paramagnetic actinide complexes. Preliminary Eyring analysis has provided activation parameters of ΔG double-dagger 295 = 56 kJ/M, ΔH double-dagger = 38 kJ/M, and ΔS double-dagger = -60 J/M-K for the plutonyl triscarbonate system, suggesting an associative transition state for the plutonyl (VI) carbonate complex self-exchange reaction. Experiments for determination of the activation parameters for the americium (VI) carbonate system are in progress

Feedback på arbejdspladser

DEFF Research Database (Denmark)

Holdt Christensen, Peter

Feedback på arbejdspladser er vigtig. Men feedback er også et populært begreb mange taler med om uden dog at vide sig helt sikker på hvad det er. Formålet med denne bog er at bidrage til en bedre forståelse af hvad feedback er, hvordan det fungerer og dermed hvordan arbejdspladser bedst muligt bør...... understøtte feedback. Med udgangspunkt i forskningen identificeres centrale udfordringer ved feedback, bl.a. hvorfor det kan være svært at give præcis feedback, hvordan forholdet mellem lederen og den ansatte påvirker den feedback der gives, og hvad der kendetegner en feedback kultur. Bogen er skrevet til...... undervisere og studerende på videregående uddannelser samt praktikere der ønsker en systematisk og forskningsbaseret forståelse af feedback på arbejdspladser. Bogen er således ikke en kogebog til bedre feedback, men en analyse og diskussion af hvad forskningen ved om feedback, og bidrager med inspiration og...

Oral-facial-digital syndrome with mesoaxial polysyndactyly, common AV canal, hirschsprung disease and sacral dysgenesis: Probably a transitional type between II, VI, variant of type VI or a new type

Directory of Open Access Journals (Sweden)

Rabah M. Shawky

2014-07-01

Full Text Available We report a 4 month old male infant, the first in order of birth of healthy first cousin consanguineous parents who has many typical features of oral-facial-digital syndrome type VI (OFDS VI including hypertelorism, bilateral convergent squint, depressed nasal bridge, and wide upturned nares, low set posteriorly rotated ears, long philtrum, gum hyperplasia with notches of the alveolar borders, high arched palate, and hyperplastic oral frenula. He has mesoaxial and postaxial, polysyndactyly which is the specific feature of OFDS VI, however the cerebellum is normal on MRI brain. He has also some rare congenital anomalies including common atrioventricular canal, hirschsprung disease, and sacral dysgenesis. This patient may have a transitional type between II and VI, a variant of type VI or a new type.

Hvad skal vi med Trump-satire?

DEFF Research Database (Denmark)

Møller, Mette

2017-01-01

Trump-satire er et stort hit, og særligt en lang række satiriske videohilsner til Trump fra lande verden over får folk til at trække på smilebåndet. Men hvorfor er det så sjovt at gøre grin med Trump, og hvad kan vi bruge den politiske humor til?......Trump-satire er et stort hit, og særligt en lang række satiriske videohilsner til Trump fra lande verden over får folk til at trække på smilebåndet. Men hvorfor er det så sjovt at gøre grin med Trump, og hvad kan vi bruge den politiske humor til?...

Analysis of KROTOS KS-2 and KS-4 steam explosion experiments with TEXAS-VI

Energy Technology Data Exchange (ETDEWEB)

Chen, Ronghua, E-mail: rhchen@mail.xjtu.edu.cn [State Key Laboratory of Multiphase Flow in Power Engineering, School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Jun [Nuclear Engineering and Engineering Physics, College of Engineering, University of Wisconsin Madison, WI 53706 (United States); Su, G.H.; Qiu, Suizheng [State Key Laboratory of Multiphase Flow in Power Engineering, School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Corradini, M.L., E-mail: Corradini@engr.wisc.edu [Nuclear Engineering and Engineering Physics, College of Engineering, University of Wisconsin Madison, WI 53706 (United States)

2016-12-01

Highlights: • The KS-2 and KS-4 steam explosion experiments were analyzed by TEXAS-VI. • The coarse mixing status up to the explosion triggering time was well predicted by TEXAS-VI. • The predicted dynamic explosion pressure was in good agreement with the experimental results. - Abstract: TEXAS-VI is a transient, three-field, one-dimensional mechanistic model for the steam explosion phenomena. A fuel solidification model and associated fragmentation criteria of the solidifying particle for both the mixing phase and explosion phase were developed and incorporated into TEXAS-VI to account for solidification. In the present study, TEXAS-VI was used to analyze the KS-2 and KS-4 steam explosion experiments, which were performed in the KROTOS facility as part of the OECD-SERENA-2 program. In the simulation, the KROTOS experimental facility was modeled as Eulerian control volumes based on the facility geometry. The molten corium jet was divided up into a series of LaGrangian master particles equal to the initial jet diameter. Both the mixing phase and the explosion phase of the experiments were simulated by TEXAS-VI. Comparison to test data indicates that the fuel jet kinematics and the vapor volume during the mixing phase were well predicted by TEXAS-VI. The TEXAS-VI prediction of the dynamic explosion pressure at different axial locations in the test was also in good agreement with the experimental results. The maximum pressure of KS-2 and KS-4 predicted by TEXAS-VI were 16.7 MPa and 41.9 MPa, respectively. The KS-4 maximum steam explosion pressure predicted by TEXAS-VI was higher than that of KS-2, which was consistent with experiment observation. The observed differences of the dynamic explosion pressure between the KS-2 and KS-4 experiments were also successfully simulated by TEXAS-VI. This suggests that TEXAS-VI is able to analyze the effect of prototypic melt compositions on the steam explosion phenomena. Additional benchmarking and evaluations are ongoing.

Using Feedback to Promote Physical Activity: The Role of the Feedback Sign.

Science.gov (United States)

Kramer, Jan-Niklas; Kowatsch, Tobias

2017-06-02

Providing feedback is a technique to promote health behavior that is emphasized by behavior change theories. However, these theories make contradicting predictions regarding the effect of the feedback sign-that is, whether the feedback signals success or failure. Thus, it is unclear whether positive or negative feedback leads to more favorable behavior change in a health behavior intervention. The aim of this study was to examine the effect of the feedback sign in a health behavior change intervention. Data from participants (N=1623) of a 6-month physical activity intervention was used. Participants received a feedback email at the beginning of each month. Feedback was either positive or negative depending on the participants' physical activity in the previous month. In an exploratory analysis, change in monthly step count averages was used to evaluate the feedback effect. The feedback sign did not predict the change in monthly step count averages over the course of the intervention (b=-84.28, P=.28). Descriptive differences between positive and negative feedback can be explained by regression to the mean. The feedback sign might not influence the effect of monthly feedback emails sent out to participants of a large-scale physical activity intervention. However, randomized studies are needed to further support this conclusion. Limitations as well as opportunities for future research are discussed. ©Jan-Niklas Kramer, Tobias Kowatsch. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 02.06.2017.

KENO-VI: A Monte Carlo Criticality Program with generalized quadratic geometry

International Nuclear Information System (INIS)

Hollenbach, D.F.; Petrie, L.M.; Landers, N.F.

1993-01-01

This report discusses KENO-VI which is a new version of the KENO monte Carlo Criticality Safety developed at Oak Ridge National Laboratory. The purpose of KENO-VI is to provide a criticality safety code similar to KENO-V.a that possesses a more general and flexible geometry package. KENO-VI constructs and processes geometry data as sets of quadratic equations. A lengthy set of simple, easy-to-use geometric functions, similar to those provided in KENO-V.a., and the ability to build more complex geometric shapes represented by sets of quadratic equations are the heart of the geometry package in KENO-VI. The code's flexibility is increased by allowing intersecting geometry regions, hexagonal as well as cuboidal arrays, and the ability to specify an array boundary that intersects the array

Chemistry of the Colloidal Group II-VI Nanocrystal Synthesis

Energy Technology Data Exchange (ETDEWEB)

Liu, Haitao [Univ. of California, Berkeley, CA (United States)

2007-05-17

In the last two decades, the field of nanoscience andnanotechnology has witnessed tremendous advancement in the synthesis andapplication of group II-VI colloidal nanocrystals. The synthesis based onhigh temperature decomposition of organometallic precursors has becomeone of the most successful methods of making group II-VI colloidalnanocrystals. This methodis first demonstrated by Bawendi and coworkersin 1993 to prepare cadmium chalcogenide colloidal quantum dots and laterextended by others to prepare other group II-VI quantum dots as well asanisotropic shaped colloidal nanocrystals, such as nanorod and tetrapod.This dissertation focuses on the chemistry of this type of nanocrystalsynthesis. The synthesis of group II-VI nanocrystals was studied bycharacterizing the molecular structures of the precursors and productsand following their time evolution in the synthesis. Based on theseresults, a mechanism was proposed to account for the 2 reaction betweenthe precursors that presumably produces monomer for the growth ofnanocrystals. Theoretical study based on density functional theorycalculations revealed the detailed free energy landscape of the precursordecomposition and monomerformation pathway. Based on the proposedreaction mechanism, a new synthetic method was designed that uses wateras a novel reagent to control the diameter and the aspect ratio of CdSeand CdS nanorods.

Kinetics of U(VI) reduction by a dissimilatory Fe(III)-reducing bacterium under non-growth conditions

International Nuclear Information System (INIS)

Truex, M.J.; Peyton, B.M.; Valentine, N.B.; Gorby, Y.A.

1997-01-01

Dissimilatory metal-reducing microorganisms may be useful in processes designed for selective removal of uranium from aqueous streams. These bacteria can use U(VI) as an electron acceptor and thereby reduce soluble U(VI) to insoluble U(IV). While significant research has been devoted to demonstrating and describing the mechanism of dissimilatory metal reduction, the reaction kinetics necessary to apply this for remediation processes have not been adequately defined. In this study, pure culture Shewanella alga strain BrY reduced U(VI) under non-growth conditions in the presence of excess lactate as the electron donor. Initial U(VI) concentrations ranged from 13 to 1,680microM. A maximum specific U(VI) reduction rate of 2.37 micromole-U(VI)/(mg-biomass h) and Monod half-saturation coefficient of 132 microM-U(VI) were calculated from measured U(VI) reduction rates. U(VI) reduction activity was sustained at 60% of this rate for at least 80 h. The initial presence of oxygen at a concentration equal to atmospheric saturation at 22 C delays but does not prevent U(VI) reduction. The rate of U(VI) reduction by BrY is comparable or better than rates reported for other metal reducing species. BrY reduces U(VI) at a rate that is 30% of its Fe(III) reduction rate

Towards a consistent geochemical model for prediction of uranium(VI) removal from groundwater by ferrihydrite

International Nuclear Information System (INIS)

Gustafsson, Jon Petter; Daessman, Ellinor; Baeckstroem, Mattias

2009-01-01

Uranium(VI), which is often elevated in granitoidic groundwaters, is known to adsorb strongly to Fe (hydr)oxides under certain conditions. This process can be used in water treatment to remove U(VI). To develop a consistent geochemical model for U(VI) adsorption to ferrihydrite, batch experiments were performed and previous data sets reviewed to optimize a set of surface complexation constants using the 3-plane CD-MUSIC model. To consider the effect of dissolved organic matter (DOM) on U(VI) speciation, new parameters for the Stockholm Humic Model (SHM) were optimized using previously published data. The model, which was constrained from available X-ray absorption fine structure (EXAFS) spectroscopy evidence, fitted the data well when the surface sites were divided into low- and high-affinity binding sites. Application of the model concept to other published data sets revealed differences in the reactivity of different ferrihydrites towards U(VI). Use of the optimized SHM parameters for U(VI)-DOM complexation showed that this process is important for U(VI) speciation at low pH. However in neutral to alkaline waters with substantial carbonate present, Ca-U-CO 3 complexes predominate. The calibrated geochemical model was used to simulate U(VI) adsorption to ferrihydrite for a hypothetical groundwater in the presence of several competitive ions. The results showed that U(VI) adsorption was strong between pH 5 and 8. Also near the calcite saturation limit, where U(VI) adsorption was weakest according to the model, the adsorption percentage was predicted to be >80%. Hence U(VI) adsorption to ferrihydrite-containing sorbents may be used as a method to bring down U(VI) concentrations to acceptable levels in groundwater

Predicting chromium (VI) adsorption rate in the treatment of liquid ...

African Journals Online (AJOL)

Administrator

The adsorption rate of chromium (VI) on commercial activated carbon during the ... time and initial chromium (VI) ion concentration. .... model, the separation factor r, according to Calvo et al (2001) cited .... Lead (II) and nickel (II) adsorption kinetics .... heavy metal by Talaromyces helicus: a trained fungus for copper and.

Cloning and expression of a Vi mimotope of Salmonella enterica ...

African Journals Online (AJOL)

STORAGESEVER

2009-09-15

Sep 15, 2009 ... A recombinant His-Vi protein of Salmonella enterica serovar Typhi was successfully constructed and cloned into ... mainly through consumption of food or water contami- nated with .... and healthy individuals (double arrows) followed by the detection using recombinant His-Vi protein as the primary antibody ...

Uranium(VI) sorption on iron oxides in Hanford Site sediment: Application of a surface complexation model

International Nuclear Information System (INIS)

Um, Wooyong; Serne, R. Jeffrey; Brown, Christopher F.; Rod, Kenton A.

2008-01-01

Sorption of U(VI) on Hanford fine sand (HFS) with varying Fe-oxide (especially ferrihydrite) contents showed that U(VI) sorption increased with the incremental addition of synthetic ferrihydrite into HFS, consistent with ferrihydrite being one of the most reactive U(VI) sorbents present in natural sediments. Surface complexation model (SCM) calculations for U(VI) sorption, using only U(VI) surface-reaction constants obtained from U(VI) sorption data on freshly synthesized ferrihydrite at different pHs, were similar to the measured U(VI) sorption results on pure synthetic ferrihydrite and on HFS with high contents of ferrihydrite (5 wt%) added. However, the SCM prediction using only U(VI) sorption reactions and constants for synthetic ferrihydrite overestimated U(VI) sorption on the natural HFS or HFS with addition of low amounts of added ferrihydrite (1 wt% added). Over-predicted U(VI) sorption was attributed to reduced reactivity of natural ferrihydrite present in Hanford Site sediments, compared to freshly prepared synthetic ferrihydrite. Even though the SCM general composite (GC) approach is considered to be a semi-quantitative estimation technique for contaminant sorption, which requires systematic experimental data on the sorbent-sorbate system being studied to obtain credible SCM parameters, the general composite SCM model was still found to be a useful technique for describing U(VI) sorption on natural sediments. Based on U(VI) batch sorption results, two simple U(VI) monodentate surface species, SO U O 2 HCO 3 and SO U O 2 OH on ferrihydrite and phyllosillicate in HFS, respectively, can be successfully used to describe U(VI) sorption onto Hanford Site sediment contacting varying geochemical solutions

Effects of longitudinal small-group learning on delivery and receipt of communication skills feedback.

Science.gov (United States)

Chou, Calvin L; Masters, Dylan E; Chang, Anna; Kruidering, Marieke; Hauer, Karen E

2013-11-01

Although feedback is a critical component of learning, recent data suggest that learners may discount feedback they receive. The emotional threat inherent in feedback can contribute to its ineffectiveness, particularly for sensitive topics like communication skills. Longitudinal relationships among peers may increase their sense of safety and soften the perceived threat of feedback to allow students to give, receive and potentially more effectively incorporate feedback. We studied the effects of prior shared learning experiences among medical students in the delivery and receipt of feedback on clinical (communication) skills. During a formative clinical skills examination, we divided Year 3 students at a US medical school into two subgroups comprising, respectively, small-group classmates from a 2-year longitudinal pre-clerkship clinical skills course (with prior peer-learning relationships), and peers with no prior shared small-group coursework. Students in both subgroups observed peers in a simulated clinical case and then provided feedback, which was videotaped, transcribed and coded. Feedback recipients also completed a survey on their perceptions of the feedback. Students valued the feedback they received and intended to enact it, regardless of whether they had prior peer-learning relationships. Coding of feedback revealed high specificity. Feedback providers who had prior peer-learning relationships with recipients provided more specific corrective feedback on communication skills than those with no such relationships (p = 0.014); there was no significant difference between subgroups in the provision of reinforcing feedback on communication skills. Year 3 medical student peers can deliver specific feedback on clinical skills; prior peer-learning relationships in pre-clerkship clinical skills courses enrich the provision of specific corrective feedback about communication skills. Feedback between peers with pre-existing peer-learning relationships represents

Ferrate(VI) as a greener oxidant: Electrochemical generation and treatment of phenol.

Science.gov (United States)

Sun, Xuhui; Zhang, Qi; Liang, He; Ying, Li; Xiangxu, Meng; Sharma, Virender K

2016-12-05

Ferrate(VI) (Fe(VI)O4(2-), Fe(VI)) is a greener oxidant in the treatment of drinking water and wastewater. The electrochemical synthesis of Fe(VI) may be considered environmentally friendly because it involves one-step process to convert Fe(0) to Fe(VI) without using harmful chemicals. Electrolysis was performed by using a sponge iron as an anode in NaOH solution at different ionic strengths. The cyclic voltammetric (CV) curves showed that the sponge iron had higher electrical activity than the grey cast iron. The optimum current density was 0.054mAcm(-2) in 10M NaOH solution, which is much lower than the electrolyte concentrations used in other electrode materials. A comparison of current efficiency and energy consumption was conducted and is briefly discussed. The generated ferrate solution was applied to degrade phenol in water at two levels (2mgL(-1) and 5mgL(-1)). The maximum removal efficiency was ∼70% and the optimum pH for phenol treatment was 9.0. Experiments on phenol removal using conventional coagulants (ferric chloride (FeCl3) and polyaluminium chloride (PAC)) were performed independently to demonstrate that removal of phenol by Fe(VI) occurred mainly by oxidative transformation. A combination of Fe(VI) and coagulant may be advantageous in enhancing removal efficiency, adjusting pH, and facilitating flocculation. Copyright © 2015 Elsevier B.V. All rights reserved.

The O VI Mystery: Mismatch between X-Ray and UV Column Densities

Science.gov (United States)

Mathur, S.; Nicastro, F.; Gupta, A.; Krongold, Y.; McLaughlin, B. M.; Brickhouse, N.; Pradhan, A.

2017-12-01

The UV spectra of Galactic and extragalactic sightlines often show O VI absorption lines at a range of redshifts, and from a variety of sources from the Galactic circumgalactic medium to active galactic nuclei (AGN) outflows. Inner shell O VI absorption is also observed in X-ray spectra (at λ =22.03 Å), but the column density inferred from the X-ray line was consistently larger than that from the UV line. Here we present a solution to this discrepancy for the z = 0 systems. The O II Kβ line {}4{S}0\\to {(}3D)3{p}4P at 562.40 eV (≡22.04 Å) is blended with the O VI Kα line in X-ray spectra. We estimate the strength of this O II line in two different ways, and show that in most cases the O II line accounts for the entire blended line. The small amount of O VI equivalent width present in some cases has column density entirely consistent with the UV value. This solution to the O VI discrepancy, however, does not apply to high column-density systems like AGN outflows. We discuss other possible causes to explain their UV/X-ray mismatch. The O VI and O II lines will be resolved by gratings on board the proposed mission Arcus and the concept mission Lynx, and would allow the detection of weak O VI lines not just at z = 0, but also at higher redshift.

Sediment studies of the biological factors controlling the reduction of U(VI)

International Nuclear Information System (INIS)

Lovley, Derek R.

2004-01-01

Studies were conducted primarily with sediments, both in laboratory incubations and in a field experiment, with supporting studies with pure cultures. To our knowledge the sediment studies were the first on microbial U(VI) reduction in actual uranium-contaminated subsurface sediments, under conditions that mimic those found in situ. Important findings included: (1) U(VI) reduction is a biotic process in subsurface sediments. (2) U(VI) reduction can be stimulated most effectively with the addition of acetate. Although it had been speculated that microbial U(VI) reduction might be capable of this type of environmental remediation ever since the discovery of microbial U(VI) reduction, this had not been previously demonstrated under environmentally relevant conditions. (3) U(VI) is reduced concurrently with Fe(III) and prior to sulfate reduction. U(VI) and Fe(III) reduction proceeded concurrently, accompanied by a dramatic enrichment in organisms in the Geobacteraceae. Sulfate-reducing microorganisms do not appear to be important components of the microbial community reducing U(VI) in these subsurface sediments. (4) Nitrate has important influences on U(VI) reduction. Nitrate inhibits the reduction of metals until nitrate is depleted. Fe(III)-reducing microorganisms such as Geobacter metallireducens and Desulfitobacterium species can oxidize Fe(II) with the reduction of nitrate which is an important consideration because our previous studies have demonstrated that freshly precipitated Fe(III) oxides can reoxidize U(IV) to U(VI). The discovery that G. metallireducens can ''run backwards'' and oxidize U(IV) when nitrate is present reveals another mechanism preventing precipitation of U(IV) in the presence of nitrate as well as potential novel strategy for removing uranium from the subsurface after a site has been remediated. (5) Importance of understanding Fe(III) forms available for microbial reduction. Fe(III) is orders of magnitude more abundant than U(VI) as an

Chromium VI and stomach cancer: a meta-analysis of the current epidemiological evidence.

Science.gov (United States)

Welling, Roberta; Beaumont, James J; Petersen, Scott J; Alexeeff, George V; Steinmaus, Craig

2015-02-01

Chromium VI (hexavalent chromium, Cr(VI)) is an established cause of lung cancer, but its association with gastrointestinal cancer is less clear. The goal of this study was to examine whether the current human epidemiological research on occupationally inhaled Cr(VI) supports the hypothesis that Cr(VI) is associated with human stomach cancer. Following a thorough literature search and review of individual studies, we used meta-analysis to summarise the current epidemiological literature on inhaled Cr(VI) and stomach cancer, explore major sources of heterogeneity, and assess other elements of causal inference. We identified 56 cohort and case-control studies and 74 individual relative risk (RR) estimates on stomach cancer and Cr(VI) exposure or work in an occupation associated with high Cr(VI) exposure including chromium production, chrome plating, leather work and work with Portland cement. The summary RR for all studies combined was 1.27 (95% CI 1.18 to 1.38). In analyses limited to only those studies identifying increased risks of lung cancer, the summary RR for stomach cancer was higher (RR=1.41, 95% CI 1.18 to 1.69). Overall, these results suggest that Cr(VI) is a stomach carcinogen in humans, which is consistent with the tumour results reported in rodent studies. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

GeoViQua: quality-aware geospatial data discovery and evaluation

Science.gov (United States)

Bigagli, L.; Papeschi, F.; Mazzetti, P.; Nativi, S.

2012-04-01

GeoViQua (QUAlity aware VIsualization for the Global Earth Observation System of Systems) is a recently started FP7 project aiming at complementing the Global Earth Observation System of Systems (GEOSS) with rigorous data quality specifications and quality-aware capabilities, in order to improve reliability in scientific studies and policy decision-making. GeoViQua main scientific and technical objective is to enhance the GEOSS Common Infrastructure (GCI) providing the user community with innovative quality-aware search and evaluation tools, which will be integrated in the GEO-Portal, as well as made available to other end-user interfaces. To this end, GeoViQua will promote the extension of the current standard metadata for geographic information with accurate and expressive quality indicators, also contributing to the definition of a quality label (GEOLabel). GeoViQua proposed solutions will be assessed in several pilot case studies covering the whole Earth Observation chain, from remote sensing acquisition to data processing, to applications in the main GEOSS Societal Benefit Areas. This work presents the preliminary results of GeoViQua Work Package 4 "Enhanced geo-search tools" (WP4), started in January 2012. Its major anticipated technical innovations are search and evaluation tools that communicate and exploit data quality information from the GCI. In particular, GeoViQua will investigate a graphical search interface featuring a coherent and meaningful aggregation of statistics and metadata summaries (e.g. in the form of tables, charts), thus enabling end users to leverage quality constraints for data discovery and evaluation. Preparatory work on WP4 requirements indicated that users need the "best" data for their purpose, implying a high degree of subjectivity in judgment. This suggests that the GeoViQua system should exploit a combination of provider-generated metadata (objective indicators such as summary statistics), system-generated metadata (contextual

Immobilization of Cr(Vi) as a contaminant from soil by iron compounds; Inmovilizacion de Cr(VI) como contaminante del suelo por compuestos de hierro

Energy Technology Data Exchange (ETDEWEB)

Marin A, M. de J.; Romero G, E. T. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Reyes G, L. R. [Universidad Autonoma del Estado de Hidalgo, Centro de Investigacion en Ciencias de la Tierra, Carretera Pachuca-Tulancingo Km. 4.5, Pachuca 42184, Hidalgo (Mexico)], e-mail: elizabeth.romero@inin.gob.mx

2008-07-01

The objective of this research was to determine the physicochemical and surface properties of Fe{sup 0} and FeS to select the appropriate radioactive material for use in the design of artificial barriers or walls and remove Cr (Vi). The physicochemical characterization was carried out of iron: Fe{sup 0} and FeS, using scanning electron microscopy of high vacuum, X-ray diffraction and thermal gravimetric analysis techniques. As for the characterization of the surface, was used to determine the surface area, point of zero charge, density of active sites and kinetics of moisture. We obtained a solution of Cr (Vi) by elution of deionized water on the pollution land of Buenavista, Guanajuato. The concentration of Cr (Vi) from a stock solution was 55.56 mg / L determined by UV-Vis spectrophotometry. Stripping or maximum immobilization of Cr (Vi) with Fe{sup 0} (material chosen by their physicochemical and surface properties) was 68.25% using Fe{sup 0}, at a concentration less than 0.1, ph equal to 3 and a contact time of 24 hours. (Author)

Ferric chloride modified zeolite in wastewater on Cr (VI) adsorption characteristics

Science.gov (United States)

Wu, Xiaoqing; Zhang, Kang; Chen, Wen; Zhang, Hua

2018-03-01

Zeolite was modified by ferric chloride(Fe-Z) removal Cr (VI) ion from wastewater. The results showed that the effect of Cr(VI) adsorption on modified zeolite depended significantly on pH. It is favorable for the adsorption of Cr(VI) in acid condition. The Langmuir isotherm model has high fitting accuracy with experimental data, demonstrated that is monolayer adsorption and chemical adsorption.The pseudo-second-order equation provided the best correlation to the data. The model can describe the adsorption reaction process well.

29 CFR 1910.1026 - Chromium (VI).

Science.gov (United States)

2010-07-01

... allows employees to consume food or beverages at a worksite where chromium (VI) is present, the employer... effect on productivity. 2. Plating Bath Surface Tension Management and Fume Suppression • Lower surface...

Are All Competencies Equal in the Eyes of Residents? A Multicenter Study of Emergency Medicine Residents' Interest in Feedback.

Science.gov (United States)

Bentley, Suzanne; Hu, Kevin; Messman, Anne; Moadel, Tiffany; Khandelwal, Sorabh; Streich, Heather; Noelker, Joan

2017-01-01

Feedback, particularly real-time feedback, is critical to resident education. The emergency medicine (EM) milestones were developed in 2012 to enhance resident assessment, and many programs use them to provide focused resident feedback. The purpose of this study was to evaluate EM residents' level of interest in receiving real-time feedback on each of the 23 competencies/sub-competencies. This was a multicenter cross-sectional study of EM residents. We surveyed participants on their level of interest in receiving real-time on-shift feedback on each of the 23 competencies/sub-competencies. Anonymous paper or computerized surveys were distributed to residents at three four-year training programs and three three-year training programs with a total of 223 resident respondents. Residents rated their level of interest in each milestone on a six-point Likert-type response scale. We calculated average level of interest for each of the 23 sub-competencies, for all 223 respondents and separately by postgraduate year (PGY) levels of training. One-way analyses of variance were performed to determine if there were differences in ratings by level of training. The overall survey response rate across all institutions was 82%. Emergency stabilization had the highest mean rating (5.47/6), while technology had the lowest rating (3.24/6). However, we observed no differences between levels of training on any of the 23 competencies/sub-competencies. Residents seem to ascribe much more value in receiving feedback on domains involving high-risk, challenging procedural skills as compared to low-risk technical and communication skills. Further studies are necessary to determine whether residents' perceived importance of competencies/sub-competencies needs to be considered when developing an assessment or feedback program based on these 23 EM competencies/sub-competencies.

Are All Competencies Equal in the Eyes of Residents? A Multicenter Study of Emergency Medicine Residents’ Interest in Feedback

Science.gov (United States)

Bentley, Suzanne; Hu, Kevin; Messman, Anne; Moadel, Tiffany; Khandelwal, Sorabh; Streich, Heather; Noelker, Joan

2017-01-01

Introduction Feedback, particularly real-time feedback, is critical to resident education. The emergency medicine (EM) milestones were developed in 2012 to enhance resident assessment, and many programs use them to provide focused resident feedback. The purpose of this study was to evaluate EM residents’ level of interest in receiving real-time feedback on each of the 23 competencies/sub-competencies. Methods This was a multicenter cross-sectional study of EM residents. We surveyed participants on their level of interest in receiving real-time on-shift feedback on each of the 23 competencies/sub-competencies. Anonymous paper or computerized surveys were distributed to residents at three four-year training programs and three three-year training programs with a total of 223 resident respondents. Residents rated their level of interest in each milestone on a six-point Likert-type response scale. We calculated average level of interest for each of the 23 sub-competencies, for all 223 respondents and separately by postgraduate year (PGY) levels of training. One-way analyses of variance were performed to determine if there were differences in ratings by level of training. Results The overall survey response rate across all institutions was 82%. Emergency stabilization had the highest mean rating (5.47/6), while technology had the lowest rating (3.24/6). However, we observed no differences between levels of training on any of the 23 competencies/sub-competencies. Conclusion Residents seem to ascribe much more value in receiving feedback on domains involving high-risk, challenging procedural skills as compared to low-risk technical and communication skills. Further studies are necessary to determine whether residents’ perceived importance of competencies/sub-competencies needs to be considered when developing an assessment or feedback program based on these 23 EM competencies/sub-competencies. PMID:28116012

Validación de un ELISA tipo inhibición para cuantificar polisacárido Vi en la vacuna antitifoídica cubana vax-TyVi

Directory of Open Access Journals (Sweden)

Esther María Fajardo

2006-08-01

Full Text Available Se describe la validación de un ELISA tipo inhibición, reportado por primera vez en la literatura científica para cuantificar un antígeno vacunal: el polisacárido Vi de Salmonella Typhi, para ser empleado en el control de la calidad de la vacuna antitifoídica cubana vax- TyViâ. El ensayo consta de seis pasos: 1 Recubrimiento de placa de reacción con poli-L-lisina y posteriormente polisacárido Vi; 2 Bloqueo con leche descremada; 3 Inhibición o neutralización en tubos de suero anti-Vi de conejo, respectivamente, con polisacárido Vi de Curva de Calibración (concentraciones desde 1–32 μg/mL, control positivo y muestras de vacuna (3 diluciones; 4 Neutralización de anticuerpos anti-Vi libres, presentes en las mezclas anteriores, por el Polisacárido de Recubrimiento; 5 Reconocimiento de anticuerpos anti-Vi unidos a la placa (conjugado anti-IgG de conejo-fosfatasa alcalina y 6 Revelado por reacción enzima-sustrato. Los parámetros de validación estudiados y sus resultados fueron: 1 Precisión, expresada como coeficiente de variación a tres niveles de concentración de polisacárido, comprendidos en el rango de su especificación (35, 50 y 70 μg/mL y evaluada en términos de repetibilidad; precisión intraensayos (cuatro analistas y reproducibilidad (seis analistas: £ 20%; 2 Linealidad (100*R2: 99,68 %; 3 Límite de detección: 0,5 μg/mL; 4 Exactitud (recuperación para las tres diluciones de la muestra: entre 100 y 118%, y 5 Robustez: no influye 1,5 h de bloqueo (p = 0,52 ni ± 5 min para leer placa (p = 0,56; influye grandemente la calidad del agua (p = 0,026, a favor del agua para inyección. El ensayo es adecuado para los fines propuestos y es una medida de la inmunogenicidad in vitro del polisacárido Vi.

Effects of Informative and Confirmatory Feedback on Brain Activation During Negative Feedback Processing

Directory of Open Access Journals (Sweden)

Yeon-Kyoung eWoo

2015-06-01

Full Text Available The current study compared the effects of informative and confirmatory feedback on brain activation during negative feedback processing. For confirmatory feedback trials, participants were informed that they had failed the task, whereas informative feedback trials presented task relevant information along with the notification of their failure. Fourteen male undergraduates performed a series of spatial-perceptual tasks and received feedback while their brain activity was recorded. During confirmatory feedback trials, greater activations in the amygdala, dorsal anterior cingulate cortex, and the thalamus (including the habenular were observed in response to incorrect responses. These results suggest that confirmatory feedback induces negative emotional reactions to failure. In contrast, informative feedback trials elicited greater activity in the dorsolateral prefrontal cortex (DLPFC when participants experienced failure. Further psychophysiological interaction (PPI analysis revealed a negative coupling between the DLPFC and the amygdala during informative feedback relative to confirmatory feedback trials. These findings suggest that providing task-relevant information could facilitate implicit down-regulation of negative emotions following failure.

Ex-situ bioremediation of U(VI from contaminated mine water using Acidithiobacillus ferrooxidans strains

Directory of Open Access Journals (Sweden)

Maria eRomero-Gonzalez

2016-05-01

Full Text Available The ex-situ bioremoval of U(VI from contaminated water using Acidithiobacillus ferrooxidans strain 8455 and 13538 was studied under a range of pH and uranium concentrations. The effect of pH on the growth of bacteria was evaluated across the range 1.5 – 4.5 pH units. The respiration rate of At. ferrooxidans at different U(VI concentrations was quantified as a measure of the rate of metabolic activity over time using an oxygen electrode. The biosorption process was quantified using a uranyl nitrate solution, U-spiked growth media and U-contaminated mine water. The results showed that both strains of At. ferrooxidans are able to remove U(VI from solution at pH 2.5 – 4.5, exhibiting a buffering capacity at pH 3.5. The respiration rate of the micro-organism was affected at U(VI concentration of 30 mg L-1. The kinetics of the sorption fitted a pseudo-first order equation, and depended on the concentration of U(VI. The KD obtained from the biosorption experiments indicated that strain 8455 is more efficient for the removal of U(VI. A bioreactor designed to treat a solution of 100 mg U(VI L-1 removed at least 50% of the U(VI in water. The study demonstrated that At. ferrooxidans can be used for the ex-situ bioremediation of U(VI contaminated mine water.

Sensory feedback by peripheral nerve stimulation improves task performance in individuals with upper limb loss using a myoelectric prosthesis.

Science.gov (United States)

Schiefer, Matthew; Tan, Daniel; Sidek, Steven M; Tyler, Dustin J

2016-02-01

Tactile feedback is critical to grip and object manipulation. Its absence results in reliance on visual and auditory cues. Our objective was to assess the effect of sensory feedback on task performance in individuals with limb loss. Stimulation of the peripheral nerves using implanted cuff electrodes provided two subjects with sensory feedback with intensity proportional to forces on the thumb, index, and middle fingers of their prosthetic hand during object manipulation. Both subjects perceived the sensation on their phantom hand at locations corresponding to the locations of the forces on the prosthetic hand. A bend sensor measured prosthetic hand span. Hand span modulated the intensity of sensory feedback perceived on the thenar eminence for subject 1 and the middle finger for subject 2. We performed three functional tests with the blindfolded subjects. First, the subject tried to determine whether or not a wooden block had been placed in his prosthetic hand. Second, the subject had to locate and remove magnetic blocks from a metal table. Third, the subject performed the Southampton Hand Assessment Procedure (SHAP). We also measured the subject's sense of embodiment with a survey and his self-confidence. Blindfolded performance with sensory feedback was similar to sighted performance in the wooden block and magnetic block tasks. Performance on the SHAP, a measure of hand mechanical function and control, was similar with and without sensory feedback. An embodiment survey showed an improved sense of integration of the prosthesis in self body image with sensory feedback. Sensory feedback by peripheral nerve stimulation improved object discrimination and manipulation, embodiment, and confidence. With both forms of feedback, the blindfolded subjects tended toward results obtained with visual feedback.

Polyaniline (PANI) modified bentonite by plasma technique for U(VI) removal from aqueous solution

International Nuclear Information System (INIS)

Liu, Xinghao; Cheng, Cheng; Xiao, Chengjian; Shao, Dadong; Xu, Zimu; Wang, Jiaquan; Hu, Shuheng; Li, Xiaolong; Wang, Weijuan

2017-01-01

Highlights: • PANI/bentonie can be synthesized by simple plasma technique. • PANI/bentonie has an excellent adsorption capacity for trace uranium in solution. • U(VI) adsorption on PANI/bentonite is a spontaneous and endothermic process. - Abstract: Polyaniline (PANI) modified bentonite (PANI/bentonie) was synthesized by plasma induced polymerization of aniline on bentonite surface, and applied to uptake of uranium(VI) ions from aqueous solution. The as-synthesized PANI/bentonie was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). Batch adsorption technique was utilized to investigate the adsorption of U(VI) on bentonite and PANI/bentonite. The adsorption of U(VI) (10 mg/L) on PANI/bentonite surface is fairly depend on solution pH, ionic strength, and temperature in solution. The modified PANI on PANI/bentonite surface significantly enhances its adsorption capability for U(VI). The presence of humic acid (HA) can sound enhance U(VI) adsorption on PANI/bentonite at pH 6.5. According to the thermodynamic parameters, the adsorption of U(VI) on PANI/bentonite surface is a spontaneous and endothermic process. The results highlight the application of PANI/bentonite composites as candidate material for the uptake of trace U(VI) from aqueous solution.

Spectroscopic Confirmation of Uranium (VI)-Carbonato Adsorption Complexes on Hematite

International Nuclear Information System (INIS)

Bargar, John R

1999-01-01

Evaluating societal risks posed by uranium contamination from waste management facilities, mining sites, and heavy industry requires knowledge about uranium transport in groundwater, often the most significant pathway of exposure to humans. It has been proposed that uranium mobility in aquifers may be controlled by adsorption of U(VI)-carbonato complexes on oxide minerals. The existence of such complexes has not been demonstrated, and little is known about their compositions and reaction stoichiometries. We have used Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopies to probe the existence, structures, and compositions of FeO surface -U(VI)-carbonato complexes on hematite throughout the pH range of uranyl uptake under conditions relevant to aquifers. U(VI)-carbonato complexes were found to be the predominant adsorbed U(VI) species at all pH values examined, a much wider pH range than previously postulated based on analogy to aqueous U(VI)-carbonato complexes, which are trace constituents at pH < 6. This result indicates the inadequacy of the common modeling assumption that the compositions and predominance of adsorbed species can be inferred from aqueous species. By extension, adsorbed carbonato complexes may be of major importance to the groundwater transport of similar actinide contaminants such as neptunium and plutonium

Experiments indicating a second hydrogen ordered phase of ice VI.

Science.gov (United States)

Gasser, Tobias M; Thoeny, Alexander V; Plaga, Lucie J; Köster, Karsten W; Etter, Martin; Böhmer, Roland; Loerting, Thomas

2018-05-14

In the last twelve years five new ice phases were experimentally prepared. Two of them are empty clathrate hydrates and three of them represent hydrogen ordered counterparts of previously known disordered ice phases. Here, we report on hydrogen ordering in ice VI samples produced by cooling at pressures up to 2.00 GPa. Based on results from calorimetry, dielectric relaxation spectroscopy, Raman spectroscopy, and powder X-ray diffraction the existence of a second hydrogen ordered polymorph related to ice VI is suggested. Powder X-ray data show the oxygen network to be the one of ice VI. For the 1.80 GPa sample the activation energy from dielectric spectroscopy is 45 kJ mol -1 , which is much larger than for the known hydrogen ordered proxy of ice VI, ice XV. Raman spectroscopy indicates the 1.80 GPa sample to be more ordered than ice XV. It is further distinct from ice XV in that it experiences hydrogen disordering above ≈103 K which is 26 K below the ice XV to ice VI disordering transition. Consequently, below 103 K it is thermodynamically more stable than ice XV, adding a stability region to the phase diagram of water. For the time being we suggest to call this new phase ice β-XV and to relabel it ice XVIII once its crystal structure is known.

Cr(VI) reduction in wastewater using a bimetallic galvanic reactor

International Nuclear Information System (INIS)

Lugo-Lugo, Violeta; Barrera-Diaz, Carlos; Bilyeu, Bryan; Balderas-Hernandez, Patricia; Urena-Nunez, Fernando; Sanchez-Mendieta, Victor

2010-01-01

The electrochemical reduction of Cr(VI)-Cr(III) in wastewater by iron and copper-iron bimetallic plates was evaluated and optimized. Iron has been used as a reducing agent, but in this work a copper-iron galvanic system in the form of bimetallic plates is applied to reducing hexavalent chromium. The optimal pH (2) and ratio of copper to iron surface areas (3.5:1) were determined in batch studies, achieving a 100% reduction in about 25 min. The Cr(VI) reduction kinetics for the bimetallic system fit a first order mechanism with a correlation of 0.9935. Thermodynamic analysis shows that the Cr(VI) reduction is possible at any pH value. However, at pH values above 3.0 for iron and 5.5 for chromium insoluble species appear, indicating that the reaction will be hindered. Continuous column studies indicate that the bimetallic copper-iron galvanic system has a reduction capacity of 9.5890 mg Cr(VI) cm -2 iron, whereas iron alone only has a capacity of 0.1269 mg Cr(VI) cm -2 . The bimetallic copper-iron galvanic system is much more effective in reducing hexavalent chromium than iron alone. The exhausted plates were analyzed by SEM, EDS, and XRD to determine the mechanism and the surface effects, especially surface fouling.

Validation of the Preverbal Visual Assessment (PreViAs) questionnaire.

Science.gov (United States)

García-Ormaechea, Inés; González, Inmaculada; Duplá, María; Andres, Eva; Pueyo, Victoria

2014-10-01

Visual cognitive integrative functions need to be evaluated by a behavioral assessment, which requires an experienced evaluator. The Preverbal Visual Assessment (PreViAs) questionnaire was designed to evaluate these functions, both in general pediatric population or in children with high risk of visual cognitive problems, through primary caregivers' answers. We aimed to validate the PreViAs questionnaire by comparing caregiver reports with results from a comprehensive clinical protocol. A total of 220 infants (visual development, as determined by the clinical protocol. Their primary caregivers completed the PreViAs questionnaire, which consists of 30 questions related to one or more visual domains: visual attention, visual communication, visual-motor coordination, and visual processing. Questionnaire answers were compared with results of behavioral assessments performed by three pediatric ophthalmologists. Results of the clinical protocol classified 128 infants as having normal visual maturation, and 92 as having abnormal visual maturation. The specificity of PreViAs questionnaire was >80%, and sensitivity was 64%-79%. More than 80% of the infants were correctly classified, and test-retest reliability exceeded 0.9 for all domains. The PreViAs questionnaire is useful to detect abnormal visual maturation in infants from birth to 24months of age. It improves the anamnesis process in infants at risk of visual dysfunctions. Copyright © 2014. Published by Elsevier Ireland Ltd.

[Adsorptive Stabilization of Soil Cr (VI) Using HDTMA Modified Montmorillonite].

Science.gov (United States)

2016-03-15

A series of organo-montomorillonites were prepared using Na-montomorillonite and hexadecyl trimethyl ammonium bromide (HDTMA). The organo-montomorillonites were then investigated for the remediation of Cr(VI) contaminated soils. FT-IR, XRD, SEM and N2 -BET, CEC, Zeta potential measurement were conducted to understand the structural changes of montmorillonites as different amounts of HDTMAs were added as modifier. The characterization results indicated that the clay interlayer spacing distance increased from 1. 25 nm to 2. 13 nm, the clay surface roughness decreased, the clay surface area reduced from 38.91 m² · g⁻¹ to 0.42 m² · g⁻¹, the clay exchangeable cation amount reduced from 62 cmol · kg⁻¹ to 9.9 cmol · kg⁻¹ and the clay surface charge changed from -29.1 mV to 5.59 mV as the dosage of HDTMA in montmorillonite was increased. The TCLP (toxicity characteristic leaching procedure) was used to evaluate the leachate toxicity of Cr(VI). The effects of the initial soil Cr(VI) concentration, montmorillonites dosage, reaction time and HDTMA modification amount were investigated, respectively. The results revealed that modification of montmorillonites would manifest an attenuated physical adsorptive effect and an enhanced electrostatic adsorptive effect on Cr(VI), suggesting electrostatic effect was the major force that resulted in improved Cr(VI) adsorption onto HDTMA modified montmorillonites.

Polyaniline (PANI) modified bentonite by plasma technique for U(VI) removal from aqueous solution

Science.gov (United States)

Liu, Xinghao; Cheng, Cheng; Xiao, Chengjian; Shao, Dadong; Xu, Zimu; Wang, Jiaquan; Hu, Shuheng; Li, Xiaolong; Wang, Weijuan

2017-07-01

Polyaniline (PANI) modified bentonite (PANI/bentonie) was synthesized by plasma induced polymerization of aniline on bentonite surface, and applied to uptake of uranium(VI) ions from aqueous solution. The as-synthesized PANI/bentonie was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). Batch adsorption technique was utilized to investigate the adsorption of U(VI) on bentonite and PANI/bentonite. The adsorption of U(VI) (10 mg/L) on PANI/bentonite surface is fairly depend on solution pH, ionic strength, and temperature in solution. The modified PANI on PANI/bentonite surface significantly enhances its adsorption capability for U(VI). The presence of humic acid (HA) can sound enhance U(VI) adsorption on PANI/bentonite at pH 6.5. According to the thermodynamic parameters, the adsorption of U(VI) on PANI/bentonite surface is a spontaneous and endothermic process. The results highlight the application of PANI/bentonite composites as candidate material for the uptake of trace U(VI) from aqueous solution.

Adsorption equilibrium studies of uranium (VI) onto cross-linked chitosan-citric acid

International Nuclear Information System (INIS)

Ho Thi Yeu Ly; Nguyen Van Suc; Vo Quang Mai; Nguyen Mong Sinh

2011-01-01

Investigation of U(VI) adsorption by the cross- linked chitosan with citric acid was conduced by bath method. Effect of parameters such as pH, contact time, adsorbent dosage and other metal cations was determined. The maximum adsorption capacity of U(VI) at pH 4 was found to be 71.43 mg U(VI) / g cross-linked chitosan - citric acid after 300 min of contact time. The Langmuir and Freundlich isotherm models were used to describe adsorption equilibrium. The correction values, R 2 of two models were found to be 0.991 and 0.997, respectively. Therefore, it could be concluded that the adsorption equilibrium for U(VI) was followed the Langmuir and the Freundlich isotherm models. (author)

Removal of Cr(VI) from Aqueous Environments Using Micelle-Clay Adsorption

Science.gov (United States)

Qurie, Mohannad; Khamis, Mustafa; Manassra, Adnan; Ayyad, Ibrahim; Nir, Shlomo; Scrano, Laura; Bufo, Sabino A.; Karaman, Rafik

2013-01-01

Removal of Cr(VI) from aqueous solutions under different conditions was investigated using either clay (montmorillonite) or micelle-clay complex, the last obtained by adsorbing critical micelle concentration of octadecyltrimethylammonium ions onto montmorillonite. Batch experiments showed the effects of contact time, adsorbent dosage, and pH on the removal efficiency of Cr(VI) from aqueous solutions. Langmuir adsorption isotherm fitted the experimental data giving significant results. Filtration experiments using columns filled with micelle-clay complex mixed with sand were performed to assess Cr(VI) removal efficiency under continuous flow at different pH values. The micelle-clay complex used in this study was capable of removing Cr(VI) from aqueous solutions without any prior acidification of the sample. Results demonstrated that the removal effectiveness reached nearly 100% when using optimal conditions for both batch and continuous flow techniques. PMID:24222757

Rateless feedback codes

DEFF Research Database (Denmark)

Sørensen, Jesper Hemming; Koike-Akino, Toshiaki; Orlik, Philip

2012-01-01

This paper proposes a concept called rateless feedback coding. We redesign the existing LT and Raptor codes, by introducing new degree distributions for the case when a few feedback opportunities are available. We show that incorporating feedback to LT codes can significantly decrease both...... the coding overhead and the encoding/decoding complexity. Moreover, we show that, at the price of a slight increase in the coding overhead, linear complexity is achieved with Raptor feedback coding....

Predicting chromium (VI) adsorption rate in the treatment of liquid ...

African Journals Online (AJOL)

The adsorption rate of chromium (VI) on commercial activated carbon during the treatment of the flocculation effluent of liquid-phase oil-based drill-cuttings has been investigated in terms of contact time and initial chromium (VI) ion concentration. Homogenizing 1 g of the activated carbon with 100 ml of the flocculation ...

Effect of selected ligands on the U(VI) immobilization by zerovalent iron

International Nuclear Information System (INIS)

Noubactep, C.

2006-01-01

The effect of Cl - , CO 3 2- , EDTA, NO 2 - , NO 3 - , PO 4 3- , SO 4 2- , and humic substances (HS) on the U(VI) co-precipitation from aqueous solutions by zerovalent iron (ZVI) was investigated in the neutral pH range.Batch experiments without shaking were conducted for 14 days mostly with five different ZVI materials (15 g/l), selected ligands (10mM) and an U(VI) solution (20 mg/l, 0.084mM). Apart from Cl - , all tested ligands induced a decrease of U(VI) coprecipitation. This decrease is attributed to the surface adsorption and complexation of the ligands at the reactive sites on the surface of ZVI and their corrosion products. The decrease of U(VI) removal was not uniform with the five ZVI materials. Generally, groundwater with elevated EDTA concentration could not be remediated with the ZVI barrier technology. The response of the system on the pre-treating by two ZVI materials in 250mM HCl indicated that in situ generated corrosion products favor an irreversible U(VI) uptake. Thus for the long term performance of ZVI barrier, the iron dissolution should continue in such a way that fresh iron oxide be always available for U(VI) coprecipitation. (author)

Influence of U(VI) on the metabolism of plant cells studied by microcalorimetry and TRLFS

Energy Technology Data Exchange (ETDEWEB)

Sachs, Susanne; Geipel, Gerhard [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biogeochemistry; Fahmy, Karim; Oertel, Jana [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biophysics; Bok, Frank [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes

2017-06-01

Uranium(VI) shows a concentration-dependent influence on the metabolic activity of plant cells. With increasing U(VI) concentration, the predominant U(VI) species in medium R{sub red} changes from UO{sub 2}HPO{sub 4}(s) to (UO{sub 2}){sub 3}(OH){sub 5}{sup +}, which may affect the bioavailability of U(VI).

Adsorption of chromium(VI) on pomace-An olive oil industry waste: Batch and column studies

International Nuclear Information System (INIS)

Malkoc, Emine; Nuhoglu, Yasar; Dundar, Murat

2006-01-01

The waste pomace of olive oil factory (WPOOF) was tested for its ability to remove chromium(VI) from aqueous solution by batch and column experiments. Various thermodynamic parameters, such as ΔG o , ΔH o and ΔS o have been calculated. The thermodynamics of chromium(VI) ion onto WPOOF system indicates spontaneous and endothermic nature of the process. The ability of WPOOF to adsorb chromium(VI) in a fixed bed column was investigated, as well. The effect of operating parameters such as flow rate and inlet metal ion concentration on the sorption characteristics of WPOOF was investigated. The longest breakthrough time and maximum of Cr(VI) adsorption is obtained at pH 2.0. The total adsorbed quantities, equilibrium uptakes and total removal percents of chromium(VI) related to the effluent volumes were determined by evaluating the breakthrough curves obtained at different flow rates and different inlet chromium(VI) concentrations for adsorbent. The data confirmed that the total amount of sorbed chromium(VI) and equilibrium chromium(VI) uptake decreased with increasing flow rate and increased with increasing inlet chromium(VI) concentration. The Adams-Bohart model were used to analyze the experimental data and the model parameters were evaluated

Remediation of Cr(VI) contaminated soil using long-duration sodium thiosulfate supported by micro–nano networks

International Nuclear Information System (INIS)

He, Lulu; Wang, Min; Zhang, Guilong; Qiu, Guannan; Cai, Dongqing; Wu, Zhengyan; Zhang, Xin

2015-01-01

Highlights: • This work aims to develop a long-duration remediation agent (LRA). • LRA was obtained using Na 2 S 2 O 3 supported by attapulgite (ATP) micro–nano networks. • ATP micro–nano networks was induced by high-energy electron beam irradiation. • LRA can effectively control the migration of Cr(VI) and reducing Cr(VI) to Cr(III). • LRA displayed high performance on the remediation of heavy metal contaminated soil. - Abstract: In this work, a long-duration remediation agent (LRA) on hexavalent chromium (Cr(VI)) was developed using sodium thiosulfate (ST) supported by attapulgite (ATP) micro–nano networks induced through high-energy electron beam (HEEB) irradiation. The ATP networks could effectively reduce the leaching amount of Cr(VI) in soil. More importantly, the ATP networks could significantly control the leaching behavior of ST, and then prolong the duration and increase the reduction efficiency of ST on Cr(VI). As a result, LRA displayed high performance on controlling the migration of Cr(VI) and reducing Cr(VI) to Cr(III). Additionally, pot experiment indicated that LRA could effectively decrease the absorbed amount of Cr(VI) in corn, and reduce the inhibition effect of Cr(VI) on the growth of corn. Therefore, this work could provide a facile approach to remediate the Cr(VI)-contaminated soil and lower the harmful effect of Cr(VI) on crop

Remediation of Cr(VI) contaminated soil using long-duration sodium thiosulfate supported by micro–nano networks

Energy Technology Data Exchange (ETDEWEB)

He, Lulu [School of Life Sciences, Anhui Agricultural University, Hefei 230036 (China); Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Wang, Min; Zhang, Guilong [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Bioenergy Forest Research Center of State Forestry Administration, Hefei 230031 (China); Qiu, Guannan [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Cai, Dongqing, E-mail: dqcai@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Bioenergy Forest Research Center of State Forestry Administration, Hefei 230031 (China); Wu, Zhengyan, E-mail: zywu@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Bioenergy Forest Research Center of State Forestry Administration, Hefei 230031 (China); Zhang, Xin, E-mail: xinzhang@ahau.edu.cn [School of Life Sciences, Anhui Agricultural University, Hefei 230036 (China)

2015-08-30

Highlights: • This work aims to develop a long-duration remediation agent (LRA). • LRA was obtained using Na{sub 2}S{sub 2}O{sub 3} supported by attapulgite (ATP) micro–nano networks. • ATP micro–nano networks was induced by high-energy electron beam irradiation. • LRA can effectively control the migration of Cr(VI) and reducing Cr(VI) to Cr(III). • LRA displayed high performance on the remediation of heavy metal contaminated soil. - Abstract: In this work, a long-duration remediation agent (LRA) on hexavalent chromium (Cr(VI)) was developed using sodium thiosulfate (ST) supported by attapulgite (ATP) micro–nano networks induced through high-energy electron beam (HEEB) irradiation. The ATP networks could effectively reduce the leaching amount of Cr(VI) in soil. More importantly, the ATP networks could significantly control the leaching behavior of ST, and then prolong the duration and increase the reduction efficiency of ST on Cr(VI). As a result, LRA displayed high performance on controlling the migration of Cr(VI) and reducing Cr(VI) to Cr(III). Additionally, pot experiment indicated that LRA could effectively decrease the absorbed amount of Cr(VI) in corn, and reduce the inhibition effect of Cr(VI) on the growth of corn. Therefore, this work could provide a facile approach to remediate the Cr(VI)-contaminated soil and lower the harmful effect of Cr(VI) on crop.

Strain/size analysis in ternary compounds AgIn{sub 5} VI{sub 8} (Vi = S, Se, Te) by X-ray diffraction; Analisis de tension/tamano en compuestos ternarios AgIn{sub 5} VI{sub 8} (VI = S, Se, Te) mediante difraccion de rayos X

Energy Technology Data Exchange (ETDEWEB)

Fermin, J. R.; Salcedo, D. Y.; Durante R, C.; Castro, J. A. [Universidad del Zulia, Facultad Experimental de Ciencias, Departamento de Fisica, Maracaibo, Zulia (Venezuela, Bolivarian Republic of)

2017-11-01

In this work, we have study the microstructural properties of the ternary compounds AgIn{sub 5} VI{sub 8} (Vi = S, Se, Te) by X-ray diffraction technique (XRD). The linewidth of the XRD profile is measured as function of the diffraction angle. Structural parameters such as, average grain size, micro strains, and crystalline dislocation density, are obtained on the framework of a strain/size analysis based on the modified Scherrer equation for Gaussian profiles. The crystalline dislocation arrange according to a Gaussian distribution function, indicating that these dislocations are randomly distributed within the grains. (Author)

Modification of zirconium diphosphate with salicylic acid and its effect on the uranium (Vi) sorption; Modificacion del difosfato de circonio con acido salicilico y su efecto sobre la sorcion de uranio (VI)

Energy Technology Data Exchange (ETDEWEB)

Almazan T, M. G.; Garcia G, N. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Simoni, E., E-mail: guadalupe.almazan@inin.gob.mx [Universidad Paris Sud, Instituto de Fisica Nuclear, Georges Clemenceau No. 15, Orsay (France)

2014-10-15

The surface of zirconium diphosphate (ZrP{sub 2}O{sub 7}) was modified with salicylic acid and its effect was evaluated on the uranium (Vi) sorption. The modified surface of the material was analyzed with different analytical techniques among which are included the atomic force microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. This analysis allowed showing that the salicylic acid is being held on the surface of the zirconium diphosphate. The reactivity of modified zirconium diphosphate compared with uranium (Vi) was investigated using the classical method of batch sorption. The analysis of sorption isotherms shows that the salicylic acid has an important effect in the uranium (Vi) sorption. According to the study conducted, the interaction among the uranium (Vi) and the surface of zirconium diphosphate modified with the salicylic acid most likely leads to the complexes formation of binary (U(Vi)/ZrP{sub 2}O{sub 7}) and ternary (U(Vi)/salicylate/ZrP{sub 2}O{sub 7}) surface. (Author)

Delineation and Diagnostic Criteria of Oral-Facial-Digital Syndrome Type VI

NARCIS (Netherlands)

Poretti, Andrea; Vitiello, Giuseppina; Hennekam, Raoul C. M.; Arrigoni, Filippo; Bertini, Enrico; Borgatti, Renato; Brancati, Francesco; D'Arrigo, Stefano; Faravelli, Francesca; Giordano, Lucio; Huisman, Thierry A. G. M.; Iannicelli, Miriam; Kluger, Gerhard; Kyllerman, Marten; Landgren, Magnus; Lees, Melissa M.; Pinelli, Lorenzo; Romaniello, Romina; Scheer, Ianina; Schwarz, Christoph E.; Spiegel, Ronen; Tibussek, Daniel; Valente, Enza Maria; Boltshauser, Eugen

2012-01-01

Oral-Facial-Digital Syndrome type VI (OFD VI) represents a rare phenotypic subtype of Joubert syndrome and related disorders (JSRD). In the original report polydactyly, oral findings, intellectual disability, and absence of the cerebellar vermis at post-mortem characterized the syndrome.

Plutonium(IV) peroxide formation in nitric medium and kinetics Pu(VI) reduction by hydrogen peroxide

International Nuclear Information System (INIS)

Maillard, C.; Adnet, J.M.

2001-01-01

Reduction of plutonium (VI) to Pu(IV) with hydrogen peroxide is a step in industrial processes used to purify plutonium nitrate solutions. This operation must be carefully controlled, in order to avoid any formation of the Pu(IV) peroxide green precipitate and to obtain exclusively Pu(IV). This led us to study the acidity and Pu and H 2 O 2 concentrations influences on the precipitate appearance and to perform a Pu(VI) reduction kinetic study on a wide range of acidities ([HNO 3 ]: 0.5 to 8 M), plutonium concentrations ([Pu(VI)]: 0.1 to 0.8 M) and [H 2 O 2 ]/[Pu(VI)] ratio (from 1 to 8). Thus, the domain of Pu(IV) peroxide formation and the reactional paths were established. With the exception of 0.5 M nitric acid medium, the kinetic curves show two distinct regims: the first one corresponds to an induction period where the Pu(VI) concentration doesn't change, the second corresponds to a linear decrease of Pu(VI). An increase of the temperature greatly accelerates the Pu(VI) reduction rate while [H 2 O 2 ]/[Pu(VI)] has almost no influence. The Pu(VI) total reduction time decreases when initial concentration of plutonium increases. By increasing nitric acid concentration from 0.5 M to 6 M, the total Pu(VI) reduction time decreases. This time increases when [HNO 3 ] varies from 6 M to 8 M. (orig.)

Synthesis and application of magnetic hydrogel for Cr(VI) removal from contaminated water

KAUST Repository

Tang, Samuel C N; Wang, Peng; Yin, Ke; Lo., Irene Man Chi

2010-01-01

Many magnetic adsorbents reported in the literature, such as iron oxides, for Cr(VI) removal have been found effective only in low pH environments. Moreover, the application of polymeric hydrogels on heavy metal removal has been hindered by difficulties in separation by filtration. In this study, a magnetic cationic hydrogel was synthesized for Cr(VI) removal from contaminated water, making use of the advantages of magnetic adsorbents and polymeric hydrogels. The magnetic hydrogel was produced by imbedding 10-nm γ-Fe2O 3 nanoparticles into the polymeric matrix via radical polymerization. Characterization of the hydrogel was undertaken with Fourier transform infrared and vibrating sample magnetometer; swelling properties were tested and anionic adsorption capacity was evaluated. The magnetic hydrogel showed a superior Cr(VI) removal capacity compared to commercial products such as MIEX®. Cr(VI) removal was independent of solution pH. Results show that Cr(VI) removal kinetics was improved drastically by grinding the bulk hydrogel into powder form. At relevant concentrations, common water anions (e.g., Cl-, SO4 2-, PO4 3-) and natural organic matter did not exhibit significant inhibition of Cr(VI) adsorption onto the hydrogel. Results of vibrating sample magnetometer indicate that the magnetic hydrogel can be easily separated from treatment systems. Regeneration of the magnetic hydrogel can be easily achieved by washing the Cr(VI)-loaded hydrogel with 0.5 M NaCl solution, with a recovery rate of about 90% of Cr(VI). © Copyright 2010, Mary Ann Liebert, Inc. 2010.

Synthesis and application of magnetic hydrogel for Cr(VI) removal from contaminated water

KAUST Repository

Tang, Samuel C N

2010-11-01

Many magnetic adsorbents reported in the literature, such as iron oxides, for Cr(VI) removal have been found effective only in low pH environments. Moreover, the application of polymeric hydrogels on heavy metal removal has been hindered by difficulties in separation by filtration. In this study, a magnetic cationic hydrogel was synthesized for Cr(VI) removal from contaminated water, making use of the advantages of magnetic adsorbents and polymeric hydrogels. The magnetic hydrogel was produced by imbedding 10-nm γ-Fe2O 3 nanoparticles into the polymeric matrix via radical polymerization. Characterization of the hydrogel was undertaken with Fourier transform infrared and vibrating sample magnetometer; swelling properties were tested and anionic adsorption capacity was evaluated. The magnetic hydrogel showed a superior Cr(VI) removal capacity compared to commercial products such as MIEX®. Cr(VI) removal was independent of solution pH. Results show that Cr(VI) removal kinetics was improved drastically by grinding the bulk hydrogel into powder form. At relevant concentrations, common water anions (e.g., Cl-, SO4 2-, PO4 3-) and natural organic matter did not exhibit significant inhibition of Cr(VI) adsorption onto the hydrogel. Results of vibrating sample magnetometer indicate that the magnetic hydrogel can be easily separated from treatment systems. Regeneration of the magnetic hydrogel can be easily achieved by washing the Cr(VI)-loaded hydrogel with 0.5 M NaCl solution, with a recovery rate of about 90% of Cr(VI). © Copyright 2010, Mary Ann Liebert, Inc. 2010.

Modeling of Cr(VI) Bioreduction Under Fermentative and Denitrifying Conditions

Science.gov (United States)

Molins, S.; Steefel, C.; Yang, L.; Beller, H. R.

2011-12-01

The mechanisms of bioreductive immobilization of Cr(VI) were investigated by reactive transport modeling of a set of flow-through column experiments performed using natural Hanford 100H aquifer sediment. The columns were continuously eluted with 5 μM Cr(VI), 5 mM lactate as the electron donor, and selected electron acceptors (tested individually). Here we focus on the two separate experimental conditions that showed the most removal of Cr(VI) from solution: fermentation and denitrification. In each case, a network of enzymatic and abiotic reaction pathways was considered to interpret the rate of chromate reduction. The model included biomass growth and decay, and thermodynamic limitations on reaction rates, and was constrained by effluent concentrations measured by IC and ICP-MS and additional information from bacterial isolates from column effluent. Under denitrifying conditions, Cr(VI) reduction was modeled as co-metabolic with nitrate reduction based on experimental observations and previous studies on a denitrifying bacterium derived from the Hanford 100H aquifer. The reactive transport model results supported this interpretation of the reaction mechanism and were used to quantify the efficiency of the process. The models results also suggest that biomass growth likely relied on a nitrogen source other than ammonium (e.g. nitrate). Under fermentative conditions and based on cell suspension studies performed on a bacterial isolate from the columns, the model assumes that Cr(VI) reduction is carried out directly by fermentative bacteria that convert lactate into acetate and propionate. The evolution to complete lactate fermentation and Cr(VI) reduction took place over a week's time and simulations were used to determine an estimate for a lower limit of the rate of chromate reduction by calibration with the flow-through column experimental results. In spite of sulfate being added to these columns, sulfate reduction proceeded at a slow rate and was not well

Velocity Feedback Experiments

Directory of Open Access Journals (Sweden)

Chiu Choi

2017-02-01

Full Text Available Transient response such as ringing in a control system can be reduced or removed by velocity feedback. It is a useful control technique that should be covered in the relevant engineering laboratory courses. We developed velocity feedback experiments using two different low cost technologies, viz., operational amplifiers and microcontrollers. These experiments can be easily integrated into laboratory courses on feedback control systems or microcontroller applications. The intent of developing these experiments was to illustrate the ringing problem and to offer effective, low cost solutions for removing such problem. In this paper the pedagogical approach for these velocity feedback experiments was described. The advantages and disadvantages of the two different implementation of velocity feedback were discussed also.

Uranium(VI) retention by Ca-bentonite under (hyper)alkaline conditions

Energy Technology Data Exchange (ETDEWEB)

Philipp, Thimo; Schmeide, Katja [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes

2017-06-01

The sorption behavior of U(VI) on Ca-bentonite was studied in saline, (hyper)alkaline solution via batch experiments. At pH 8.5-9.5 sorption is low in the presence of CO{sub 2} due to the formation of weakly sorbing uranyl carbonate species, which have been observed to dominate speciation up to pH 10 by time-resolved laser-induced fluorescence spectroscopy (TRLFS). In the pH region 10-12, U(VI) retention is almost complete. The retention can either be attributed to strongly sorbing uranyl hydroxo complexes or to a partial precipitation of uranium due to an altered solubility of U(VI) induced by ions leached out of the bentonite.

Application of NKF-6 zeolite for the removal of U(VI) from aqueous solution

International Nuclear Information System (INIS)

Pengfei Zong; Hai Wang; Hui Pan; Yaolin Zhao; Chaohui He

2013-01-01

To better understand the application of NKF-6 zeolite as an adsorbent for the removal of U(VI) from radionuclides and heavy metal ions polluted water, herein, NKF-6 zeolite was employed to remove U(VI) at different experimental conditions. The influence of solid/liquid ratio, contact time, pH, ionic strength, humic substances and temperature on sorption of U(VI) to NKF-6 zeolite was investigated using batch technique under ambient conditions. The experimental results demonstrated that the sorption of U(VI) on NKF-6 zeolite was strongly dependent on pH. The sorption property of U(VI) was influenced by ionic strength at pH 7.0. The presence of fulvic acid or humic acid promoted the sorption of U(VI) on NKF-6 zeolite at low pH values while restrained the sorption at high pH values. The thermodynamic parameters (i.e., ΔS 0 , ΔH 0 , and ΔG 0 ) calculated from the temperature-dependent sorption isotherms demonstrated that the sorption process of U(VI) on NKF-6 zeolite was endothermic and spontaneous. At low pH values, the sorption of U(VI) was dominated by outer-sphere surface complexation and ion exchange with Na + /H + on NKF-6 zeolite surfaces, while inner-sphere surface complexation was the main sorption mechanism at high pH values. From the experimental results, one can conclude that NKF-6 zeolite can be used as a potential adsorbent for the preconcentration and solidification of U(VI) from large volumes of aqueous solutions. (author)

Remediation of uranium contaminated soils with bicarbonate extraction and microbial U(VI) reduction

Science.gov (United States)

Philips , Elizabeth J.P.; Landa, Edward R.; Lovely, Derek R.

1995-01-01

A process for concentrating uranium from contaminated soils in which the uranium is first extracted with bicarbonate and then the extracted uranium is precipitated with U(VI)-reducing microorganisms was evaluated for a variety of uranuum-contaminated soils. Bicarbonate (100 mM) extracted 20–94% of the uranium that was extracted with nitric acid. The U(VI)-reducing microorganism,Desulfovibrio desulfuricans reduced the U(VI) to U(IV) in the bicarbonate extracts. In some instances unidentified dissolved extracted components, presumably organics, gave the extract a yellow color and inhibited U(VI) reduction and/or the precipitation of U(IV). Removal of the dissolved yellow material with the addition of hydrogen peroxide alleviated this inhibition. These results demonstrate that bicarbonate extraction of uranium from soil followed by microbial U(VI) reduction might be an effective mechanism for concentrating uranium from some contaminated soils.

Remediation of uranium contaminated soils with bicarbonate extraction and microbial U(VI) reduction

International Nuclear Information System (INIS)

Phillips, E.J.P.; Landa, E.R.; Lovley, D.R.

1995-01-01

A process for concentrating uranium from contaminated soils in which the uranium is first extracted with bicarbonate and then the extracted uranium is precipitated with U(VI)-reducing microorganisms was evaluated for a variety of uranium-contaminated soils. Bicarbonate (100 mM) extracted 20-94% of the uranium that was extracted with nitric acid. The U(VI)-reducing microorganism, Desulfovibrio desulfuricans reduced the U(VI) to U(IV) in the bicarbonate extracts. In some instances unidentified dissolved extracted components, presumably organics, gave the extract a yellow color and inhibited U(VI) reduction and/or the precipitation of U(IV). Removal of the dissolved yellow material with the addition of hydrogen peroxide alleviated this inhibition. These results demonstrate that bicarbonate extraction of uranium from soil followed by microbial U(VI) reduction might be an effective mechanism for concentrating uranium from some contaminated soils. (author)

Osteogenesis Imperfecta Type VI in Individuals from Northern Canada.

Science.gov (United States)

Ward, Leanne; Bardai, Ghalib; Moffatt, Pierre; Al-Jallad, Hadil; Trejo, Pamela; Glorieux, Francis H; Rauch, Frank

2016-06-01

Osteogenesis imperfecta (OI) type VI is a recessively inherited form of OI that is caused by mutations in SERPINF1, the gene coding for pigment-epithelium derived factor (PEDF). Here, we report on two apparently unrelated children with OI type VI who had the same unusual homozygous variant in intron 6 of SERPINF1 (c.787-10C>G). This variant created a novel splice site that led to the in-frame addition of three amino acids to PEDF (p.Lys262_Ile263insLeuSerGln). Western blotting showed that skin fibroblasts with this mutation produced PEDF but failed to secrete it. Both children were treated with intravenous bisphosphonates, but the treatment of Individual 1 was switched to subcutaneous injections of denosumab (dose 1 mg per kg body weight, repeated every 3 months). An iliac bone sample obtained after 5 denosumab injections (and 3 months after the last injection) showed no change in the increased osteoid parameters that are typical of OI type VI, but the number of osteoclasts in trabecular bone was markedly increased. This suggests that the effect of denosumab on osteoclast suppression is of shorter duration in children with OI type VI than what has previously been reported on adults with osteoporosis.

Chemistry of the Colloidal Group II-VI Nanocrystal Synthesis

International Nuclear Information System (INIS)

Liu, Haitao

2007-01-01

In the last two decades, the field of nanoscience and nanotechnology has witnessed tremendous advancement in the synthesis and application of group II-VI colloidal nanocrystals. The synthesis based on high temperature decomposition of organometallic precursors has become one of the most successful methods of making group II-VI colloidal nanocrystals. This method is first demonstrated by Bawendi and coworkers in 1993 to prepare cadmium chalcogenide colloidal quantum dots and later extended by others to prepare other group II-VI quantum dots as well as anisotropic shaped colloidal nanocrystals, such as nanorod and tetrapod. This dissertation focuses on the chemistry of this type of nanocrystal synthesis. The synthesis of group II-VI nanocrystals was studied by characterizing the molecular structures of the precursors and products and following their time evolution in the synthesis. Based on these results, a mechanism was proposed to account for the 2 reaction between the precursors that presumably produces monomer for the growth of nanocrystals. Theoretical study based on density functional theory calculations revealed the detailed free energy landscape of the precursor decomposition and monomer formation pathway. Based on the proposed reaction mechanism, a new synthetic method was designed that uses water as a novel reagent to control the diameter and the aspect ratio of CdSe and CdS nanorods

Local orbit feedback

International Nuclear Information System (INIS)

Anon.

1991-01-01

Critically aligned experiments are sensitive to small changes in the electron beam orbit. At the NSLS storage rings, the electron beam and photon beam motions have been monitored over the past several years. In the survey conducted in 1986 by the NSLS Users Executive Committee, experimenters requested the vertical beam position variation and the vertical angle variation, within a given fill, remain within 10 μm and 10 μr, respectively. This requires improvement in the beam stability by about one order of magnitude. At the NSLS and SSRL storage rings, the beam that is originally centered on the position monitor by a dc orbit correction is observed to have two kinds of motion: a dc drift over a storage period of several hours and a beam bounce about its nominal position. These motions are a result of the equilibrium orbit not being held perfectly stable due to time-varying errors introduced into the magnetic guide field by power supplies, mechanical vibration of the magnets, cooling water temperature variations, etc. The approach to orbit stabilization includes (1) identifying and suppressing as many noise sources on the machine as possible, (2) correcting the beam position globally (see Section 6) by controlling a number of correctors around the circumference of the machine, and (3) correcting the beam position and angle at a given source location by position feedback using local detectors and local orbit bumps. The third approach, called Local Orbit Feedback will be discussed in this section

Kinetics of Cr(III) and Cr(VI) removal from water by two floating macrophytes.

Science.gov (United States)

Maine, M A; Hadad, H R; Sánchez, G; Caffaratti, S; Pedro, M C

2016-01-01

The aim of this work was to compare Cr(III) and Cr(VI) removal kinetics from water by Pistia stratiotes and Salvinia herzogii. The accumulation in plant tissues and the effects of both Cr forms on plant growth were also evaluated. Plants were exposed to 2 and 6 mg L(-1) of Cr(III) or Cr(VI) during 30 days. At the end of the experiment, Cr(VI) removal percentages were significantly lower than those obtained for Cr(III) for both macrophytes. Cr(III) removal kinetics involved a fast and a slow component. The fast component was primarily responsible for Cr(III) removal while Cr(VI) removal kinetics involved only a slow process. Cr accumulated principally in the roots. In the Cr(VI) treatments a higher translocation from roots to aerial parts than in Cr(III) treatments was observed. Both macrophytes demonstrated a high ability to remove Cr(III) but not Cr(VI). Cr(III) inhibited the growth at the highest studied concentration of both macrophytes while Cr(VI) caused senescence. These results have important implications in the use of constructed wetlands for secondary industrial wastewater treatment. Common primary treatments of effluents containing Cr(VI) consists in its reduction to Cr(III). Cr(III) concentrations in these effluents are normally below the highest studied concentrations in this work.

Box-Behnken experimental design for chromium(VI) ions removal by bacterial cellulose-magnetite composites.

Science.gov (United States)

Stoica-Guzun, Anicuta; Stroescu, Marta; Jinga, Sorin Ion; Mihalache, Nicoleta; Botez, Adriana; Matei, Cristian; Berger, Daniela; Damian, Celina Maria; Ionita, Valentin

2016-10-01

In this study bacterial cellulose-magnetite composites were synthesised for the removal of chromium(VI) from aqueous solutions. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis and X-ray Photoelectron Spectroscopy (XPS) were used to characterize the bacterial cellulose-magnetite composites and to reveal the uniform dispersion of nanomagnetite in the BC matrix. Magnetic properties were also measured to confirm the magnetite immobilization on bacterial cellulose membrane. The effects of initial Cr(VI) concentration, solution pH and solid/liquid ratio upon chromium removal were examined using the statistical Box-Behnken Design. Because of the possibility of magnetite dissolution during chromium(VI) adsorption, the degree of iron leaching was also analysed in the same conditions as Cr(VI) adsorption. From the factors affecting chromium(VI) adsorption the most important was solution pH. The highest Cr(VI) removal efficiency was observed at pH 4, accompanied by the lowest iron leaching in the solution. The adsorption experiments also indicated that the adsorption process of chromium(VI) is well described by Freundlich adsorption model. Our results proved that the BC-magnetite composites could be used for an efficient removal of chromium(VI) from diluted solutions with a minimum magnetite dissolution during operation. Copyright © 2016 Elsevier B.V. All rights reserved.

Reaction kinetics and oxidation products formation in the degradation of ciprofloxacin and ibuprofen by ferrate(VI).

Science.gov (United States)

Zhou, Zhengwei; Jiang, Jia-Qian

2015-01-01

The treatment of ciprofloxacin (CIP) and ibuprofen (IBU) in test solutions by ferrate(VI) was investigated in this study. A series of jar test was performed in bench-scale at pH 6-9 and ferrate(VI) dose of 1-5 mg L(-1). Results demonstrated that ferrate(VI) removed CIP from test solutions efficiently, with above 70% of reduction under study conditions. In contrary, the removal rates of IBU were very low, less than 25% in all conditions. Raising ferrate(VI) dose improved the treatment performance, while the influence of solution pH was not significant at pH 6-9 compared with that of ferrate(VI) dose. In addition, kinetic studies of ferrate(VI) with both compounds were carried out at pH 8 and pH 9 (20 °C). Ferrate(VI) had a much higher reactivity with CIP than IBU at pH 8 and pH 9, with CIP's apparent second-order rate constants of 113.7±6.3 M(-1) s(-1) and 64.1±1.0 M(-1) s(-1), respectively. The rate constants of ferrate(VI) with IBU were less than 0.2 M(-1) s(-1) at pH 8 and pH 9. Furthermore, seven oxidation products (OPs) were formed during CIP degradation by ferrate(VI). The attack on the piperazinyl ring of the CIP by ferrate(VI) appeared to lead to the cleavage or hydroxylation of the rings, and the attack on the quinolone moiety by ferrate(VI) might lead to the cleavage of the double bond at the six-member heterocyclic ring. No OPs of IBU were detected during ferrate(VI) oxidation due to very small part of IBU was degraded by ferrate(VI). Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of flavin compounds on uranium(VI) reduction- kinetic study using electrochemical methods with UV-vis spectroscopy

International Nuclear Information System (INIS)

Yamasaki, Shinya; Tanaka, Kazuya; Kozai, Naofumi; Ohnuki, Toshihiko

2017-01-01

The reduction of uranium hexavalent (U(VI)) to tetravalent (U(IV)) is an important reaction because of the change in its mobility in the natural environment. Although the flavin mononucleotide (FMN) has acted as an electron shuttle for the U(VI) reduction in vivo system, which is called an electron mediator, only the rate constant for the electron transfer from FMN to U(VI) has been determined. This study examined the rate constant for the U(VI) reduction process by three flavin analogues (riboflavin, flavin mononucleotide, flavin adenine dinucleotide) to elucidate their substituent group effect on the U(VI) reduction rate by electrochemical methods. The formation of the U(IV) was monitored by UV-vis spectrometry at 660 nm during the constant potential electrolysis of the U(VI) solution in the presence of the mediator. The cyclic voltammograms indicated that the three flavin analogues behaved as electron mediator to reduce U(VI). The logarithmic rate constant for the U(VI) reduction was related to the standard redox potential of the mediators. This linear relationship indicated that the redox-active group of the mediator and the substituent group of the mediator dominate capability of the U(VI) reduction and its rate, respectively. The apparent reduction potential of U(VI) increased about 0.2 V in the presence of the mediators, which strongly suggests that the biological electron mediator makes the U(VI) reduction possible even under more oxidative conditions. - Highlights: • The rate constant for the U(VI) reduction by flavin analogues was determined. • The flavins showed a mediator effect on the U(VI) reduction. • The logarithmic rate constants for the U(VI) reduction was proportional to redox potential of the mediator. • The presence of the mediator increased about 0.2 V apparent redox potential of U(VI) to U(IV).

Ryger troværdigheden ned, når vi taler læreruddannelsen op?

DEFF Research Database (Denmark)

Holm, Claus

2009-01-01

Nu er vi ved at få talt læreruddannelsen op af sin lavstatus. Resultatet er, at flere søger uddannelsen. Så må vi håbe, at talen er troværdig, for ellers vil frafaldet stige.......Nu er vi ved at få talt læreruddannelsen op af sin lavstatus. Resultatet er, at flere søger uddannelsen. Så må vi håbe, at talen er troværdig, for ellers vil frafaldet stige....

ColVI myopathies: where do we stand, where do we go?

Directory of Open Access Journals (Sweden)

Allamand Valérie

2011-09-01

Full Text Available Abstract Collagen VI myopathies, caused by mutations in the genes encoding collagen type VI (ColVI, represent a clinical continuum with Ullrich congenital muscular dystrophy (UCMD and Bethlem myopathy (BM at each end of the spectrum, and less well-defined intermediate phenotypes in between. ColVI myopathies also share common features with other disorders associated with prominent muscle contractures, making differential diagnosis difficult. This group of disorders, under-recognized for a long time, has aroused much interest over the past decade, with important advances made in understanding its molecular pathogenesis. Indeed, numerous mutations have now been reported in the COL6A1, COL6A2 and COL6A3 genes, a large proportion of which are de novo and exert dominant-negative effects. Genotype-phenotype correlations have also started to emerge, which reflect the various pathogenic mechanisms at play in these disorders: dominant de novo exon splicing that enables the synthesis and secretion of mutant tetramers and homozygous nonsense mutations that lead to premature termination of translation and complete loss of function are associated with early-onset, severe phenotypes. In this review, we present the current state of diagnosis and research in the field of ColVI myopathies. The past decade has provided significant advances, with the identification of altered cellular functions in animal models of ColVI myopathies and in patient samples. In particular, mitochondrial dysfunction and a defect in the autophagic clearance system of skeletal muscle have recently been reported, thereby opening potential therapeutic avenues.

Thermodynamics of U(VI) and Eu(III) complexation by unsaturated carboxylates

Energy Technology Data Exchange (ETDEWEB)

Rawat, Neetika; Bhattacharyya, A. [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Tomar, B.S., E-mail: bstomar@barc.gov.in [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Ghanty, T.K. [Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai 400085 (India); Manchanda, V.K. [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

2011-05-10

Highlights: {yields} {Delta}H and log K determined for U(VI) and Eu(III) complexes with maleate and fumarate. {yields} log K and coordination environment of Eu(III) complexes has been studied by TRFS. {yields} Higher log K of U(VI) complexes than Eu(III) complexes is due to higher entropy. {yields} Plot of log K vs log K{sub P} suggest charge polarization in fumarate complexes. {yields} Ab initio calculations support charge polarization in fumarate complexes. - Abstract: The thermodynamic parameters ({Delta}G, {Delta}H and {Delta}S) of complexation of U(VI) and Eu(III) by unsaturated dicarboxylic acids, namely, maleic and fumaric acid, has been determined by potentiometric and microcalorimetric titrations at fixed ionic strength (I = 1.0 M) and temperature (298 K). The results show formation of 1:1 complexes by both the ligands with Eu(III). In the case of U(VI), maleate forms both 1:1 and 1:2 complexes, while only 1:1 complex was formed with fumarate. The fluorescence emission spectra of Eu(III)-dicarboxylate solutions at varying ligand to metal ratio were also used to obtain their stability constants. In addition, the fluorescence lifetimes reveal higher dehydration of Eu(III)-maleate compared to Eu(III)-fumarate which corroborates the {Delta}S values. The thermodynamic quantities suggest charge polarization effects in the case of U(VI) and Eu(III) complexes of fumarate, which is further corroborated by theoretical calculations. For the same ligand, U(VI) complexes were found to be more stable which was mainly due to higher entropy term.

Graduate Students' Needs and Preferences for Written Feedback on Academic Writing

Science.gov (United States)

Singh, Manjet Kaur Mehar

2016-01-01

The aim of this research is to examine graduate students' needs and preferences for written feedback on academic writing from their lecturers and thesis supervisors. Quantitative method via survey questionnaire was used to collect data from 21 respondents. The data collection involved Master and Doctorate students at a tertiary level institution…

Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments

Science.gov (United States)

Yin, Jun; Haggerty, Roy; Stoliker, Deborah L.; Kent, Douglas B.; Istok, Jonathan D.; Greskowiak, Janek; Zachara, John M.

2011-01-01

In the 300 Area of a U(VI)-contaminated aquifer at Hanford, Washington, USA, inorganic carbon and major cations, which have large impacts on U(VI) transport, change on an hourly and seasonal basis near the Columbia River. Batch and column experiments were conducted to investigate the factors controlling U(VI) adsorption/desorption by changing chemical conditions over time. Low alkalinity and low Ca concentrations (Columbia River water) enhanced adsorption and reduced aqueous concentrations. Conversely, high alkalinity and high Ca concentrations (Hanford groundwater) reduced adsorption and increased aqueous concentrations of U(VI). An equilibrium surface complexation model calibrated using laboratory batch experiments accounted for the decrease in U(VI) adsorption observed with increasing (bi)carbonate concentrations and other aqueous chemical conditions. In the column experiment, alternating pulses of river and groundwater caused swings in aqueous U(VI) concentration. A multispecies multirate surface complexation reactive transport model simulated most of the major U(VI) changes in two column experiments. The modeling results also indicated that U(VI) transport in the studied sediment could be simulated by using a single kinetic rate without loss of accuracy in the simulations. Moreover, the capability of the model to predict U(VI) transport in Hanford groundwater under transient chemical conditions depends significantly on the knowledge of real-time change of local groundwater chemistry.

Nicomachean Ethics VI.9: good deliberation and phronesis [Ética a Nicômaco VI.9: boa deliberação e phronesis

Directory of Open Access Journals (Sweden)

Angelo Antonio Pires de Oliveira

2017-08-01

Full Text Available In this paper, I put under scrutiny the arguments put forward by Aristotle in Nicomachean Ethics (NE VI.9. The paper has two main parts. In the first, I examine the NE VI.9’s first part where Aristotle develops the concept of good deliberation, offering its definition in 1142b27-28. In the second, I examine the connection between good deliberation and phronesis, and, then, discuss the vexata quæstio about if the lines 1142b31-33 might be read as introducing the claim that phronesis provides moral ends. [Neste artigo, analiso pormenorizadamente os argumentos apresentados por Aristóteles em Ética a Nicômaco (EN VI.9. O artigo é dividido em duas partes principais. Na primeira, abordo a primeira parte de EN VI.9 onde Aristóteles desenvolve a noção de boa deliberação, culminando com a apresentação da sua definição em 1142b27-28. Na segunda, abordo a conexão entre boa deliberação e phronesis e discuto a vexata quaestio de se as linhas 1142b31-33 podem ser lidas como introduzindo a tese de que a phronesis fornece os fins morais

Urinary carbonic anhydrase VI as a biomarker for kidney disease in pigs.

Science.gov (United States)

Nishita, Toshiho; Yatsu, Juro; Watanabe, Kazuo; Ochiai, Hideharu; Ichihara, Nobutsune; Orito, Kensuke; Arishima, Kazuyoshi

2014-11-01

This study investigated whether carbonic anhydrase (CA)-VI has utility as a biomarker in swine kidney disease. Serum chemistry, histopathology, immunohistochemical staining and enzyme-linked immunosorbent assay (ELISA) analyses were performed. In the kidney of normal healthy pigs, CA-VI was localized in the epithelial cells of the renal distal straight tubules. CA-VI levels were 16 ± 35 ng/g wet tissue and 50 ± 66 ng/mL in normal pig kidney and urine, respectively, and 136 ± 173 ng/mL in the urine of pigs with kidney disease. CA-VI urinary concentration was not correlated with urinary urea nitrogen (UUN), urinary creatinine (Cre), or urinary albumin levels in pigs with kidney disease. However, UUN and Cre levels were positively correlated in the urine of pigs with kidney disease. These data suggest that urinary CA-VI may represent a biomarker for kidney disease in pigs, particularly for disorders affecting distal straight tubules. Copyright © 2014 Elsevier Ltd. All rights reserved.

Influence of Calcite and Dissolved Calcium on Uranium(VI) Sorption to a Hanford Subsurface Sediment

International Nuclear Information System (INIS)

Dong, Wenming; Ball, William P.; Liu, Chongxuan; Wang, Zheming; Stone, Alan T.; Bai, Jing; Zachara, John M.

2005-01-01

The influence of calcite and dissolved calcium on U(VI) adsorption was investigated using a calcite-containing sandy silt/clay sediment from the U. S. Department of Energy Hanford site. U(VI) adsorption to sediment, treated sediment, and sediment size fractions was studied in solutions that both had and had not been preequilibrated with calcite, at initial [U(VI)] ) 10-7-10-5 mol/L and final pH ) 6.0- 10.0. Kinetic and reversibility studies (pH 8.4) showed rapid sorption (30 min), with reasonable reversibility in the 3-day reaction time. Sorption from solutions equilibrated with calcite showed maximum U(VI) adsorption at pH 8.4 (0.1. In contrast, calcium-free systems showed the greatest adsorption at pH 6.0-7.2. At pH > 8.4, U(VI) adsorption was identical from calcium-free and calcium-containing solutions. For calcite-presaturated systems, both speciation calculations and laser-induced fluorescence spectroscopic analyses indicated that aqueous U(VI) was increasingly dominated by Ca2UO2(CO3)3 0(aq) at pH<8.4 and that formation of Ca2UO2(CO3)3 0(aq) is what suppresses U(VI) adsorption. Above pH 8.4, aqueous U(VI) speciation was dominated by UO2(CO3)3 4- in all solutions. Finally, results also showed that U(VI) adsorption was additive in regard to size fraction but not in regard to mineral mass: Carbonate minerals may have blocked U(VI) access to surfaces of higher sorption affinity

combined effect of polyaniline emeraldine salt for removal of Cr(VI)

Indian Academy of Sciences (India)

Cr(VI) ion is one of the major industrial wastes as dichromate and chromate ions are ... more [9–12]. For the toxic nature of Cr(VI) in aqueous medium, it becomes a ... techniques such as adsorption [13–15], chemical reduction. [16], reverse ...

Probing uranyl(VI) speciation in the presence of amidoxime ligands using electrospray ionization mass spectrometry.

Science.gov (United States)

Mustapha, Adetayo M; Pasilis, Sofie P

2013-10-15

Extraction processes using poly(acrylamidoxime) resins are being developed to extract uranium from seawater. The main complexing agents in these resins are thought to be 2,6-dihydroxyiminopiperidine (DHIP) and N(1),N(5)-dihydroxypentanediimidamide (DHPD), which form strong complexes with uranyl(VI) at the pH of seawater. It is important to understand uranyl(VI) speciation in the presence of these and similar amidoxime ligands to understand factors affecting uranyl(VI) adsorption to the poly(acrylamidoxime) resins. Experiments were carried out in positive ion mode on a quadrupole ion trap mass spectrometer equipped with an electrospray ionization source. The ligands investigated were DHIP, DHPD, and N(1),N(2)-dihydroxyethanediimidamide (DHED). DHED and DHPD differ only in the number of carbons separating the oxime groups. The effects on the mass spectra of changes in uranyl(VI):ligand ratio, pH, and ligand type were examined. DHIP binds uranyl(VI) more effectively than DHPD or DHED in the pH range investigated, forming ions derived from solution-phase species with uranyl(VI):DHIP stoichiometries of 1:1, 1:2, and 2:3. The 2:3 uranyl(VI):DHIP complex appears to be a previously undescribed solution species. Ions related to uranyl(VI):DHPD complexes were detected in very low abundance. DHED is a more effective complexing agent for uranyl(VI) than DHPD, forming ions having uranyl(VI):DHED stoichiometries of 1:1, 1:2, 1:3, and 2:3. This study presents a first look at the solution chemistry of uranyl(VI)-amidoxime complexes using electrospray ionization mass spectrometry. The appearance of previously undescribed solution species suggests that the uranyl-amidoxime system is a rich and relatively complex one, requiring a more in-depth investigation. Copyright © 2013 John Wiley & Sons, Ltd.

Telephony user survey

CERN Multimedia

IT Department

2016-01-01

Let us know your needs to better plan the transition to a new CERN telephony system.   CERN is planning to upgrade its telephony network and replace the system with a new and modern VoIP infrastructure. We strive to make this transition as beneficial and smooth as possible for you. Please let us know more about your current working environment, expectations and suggestions by responding to this survey: https://cern.ch/tel-survey. The more answers we get, the better the new system will serve everyone in the future. The survey will take you about five minutes to complete; we are counting on your feedback!

Visual feedback alters force control and functional activity in the visuomotor network after stroke

Directory of Open Access Journals (Sweden)

Derek B. Archer

2018-01-01

Full Text Available Modulating visual feedback may be a viable option to improve motor function after stroke, but the neurophysiological basis for this improvement is not clear. Visual gain can be manipulated by increasing or decreasing the spatial amplitude of an error signal. Here, we combined a unilateral visually guided grip force task with functional MRI to understand how changes in the gain of visual feedback alter brain activity in the chronic phase after stroke. Analyses focused on brain activation when force was produced by the most impaired hand of the stroke group as compared to the non-dominant hand of the control group. Our experiment produced three novel results. First, gain-related improvements in force control were associated with an increase in activity in many regions within the visuomotor network in both the stroke and control groups. These regions include the extrastriate visual cortex, inferior parietal lobule, ventral premotor cortex, cerebellum, and supplementary motor area. Second, the stroke group showed gain-related increases in activity in additional regions of lobules VI and VIIb of the ipsilateral cerebellum. Third, relative to the control group, the stroke group showed increased activity in the ipsilateral primary motor cortex, and activity in this region did not vary as a function of visual feedback gain. The visuomotor network, cerebellum, and ipsilateral primary motor cortex have each been targeted in rehabilitation interventions after stroke. Our observations provide new insight into the role these regions play in processing visual gain during a precisely controlled visuomotor task in the chronic phase after stroke.

Fault Tolerant Feedback Control

DEFF Research Database (Denmark)

Stoustrup, Jakob; Niemann, H.

2001-01-01

An architecture for fault tolerant feedback controllers based on the Youla parameterization is suggested. It is shown that the Youla parameterization will give a residual vector directly in connection with the fault diagnosis part of the fault tolerant feedback controller. It turns out...... that there is a separation be-tween the feedback controller and the fault tolerant part. The closed loop feedback properties are handled by the nominal feedback controller and the fault tolerant part is handled by the design of the Youla parameter. The design of the fault tolerant part will not affect the design...... of the nominal feedback con-troller....

Sensory feedback by peripheral nerve stimulation improves task performance in individuals with upper limb loss using a myoelectric prosthesis

Science.gov (United States)

Schiefer, Matthew; Tan, Daniel; Sidek, Steven M.; Tyler, Dustin J.

2016-02-01

Objective. Tactile feedback is critical to grip and object manipulation. Its absence results in reliance on visual and auditory cues. Our objective was to assess the effect of sensory feedback on task performance in individuals with limb loss. Approach. Stimulation of the peripheral nerves using implanted cuff electrodes provided two subjects with sensory feedback with intensity proportional to forces on the thumb, index, and middle fingers of their prosthetic hand during object manipulation. Both subjects perceived the sensation on their phantom hand at locations corresponding to the locations of the forces on the prosthetic hand. A bend sensor measured prosthetic hand span. Hand span modulated the intensity of sensory feedback perceived on the thenar eminence for subject 1 and the middle finger for subject 2. We performed three functional tests with the blindfolded subjects. First, the subject tried to determine whether or not a wooden block had been placed in his prosthetic hand. Second, the subject had to locate and remove magnetic blocks from a metal table. Third, the subject performed the Southampton Hand Assessment Procedure (SHAP). We also measured the subject’s sense of embodiment with a survey and his self-confidence. Main results. Blindfolded performance with sensory feedback was similar to sighted performance in the wooden block and magnetic block tasks. Performance on the SHAP, a measure of hand mechanical function and control, was similar with and without sensory feedback. An embodiment survey showed an improved sense of integration of the prosthesis in self body image with sensory feedback. Significance. Sensory feedback by peripheral nerve stimulation improved object discrimination and manipulation, embodiment, and confidence. With both forms of feedback, the blindfolded subjects tended toward results obtained with visual feedback.

Surface complexation modeling of the effects of phosphate on uranium(VI) adsorption

Energy Technology Data Exchange (ETDEWEB)

Romero-Gonzalez, M.R.; Cheng, T.; Barnett, M.O. [Auburn Univ., AL (United States). Dept. of Civil Engeneering; Roden, E.E. [Wisconsin Univ., Madison, WI (United States). Dept. of Geology and Geophysics

2007-07-01

Previous published data for the adsorption of U(VI) and/or phosphate onto amorphous Fe(III) oxides (hydrous ferric oxide, HFO) and crystalline Fe(III) oxides (goethite) was examined. These data were then used to test the ability of a commonly-used surface complexation model (SCM) to describe the adsorption of U(VI) and phosphate onto pure amorphous and crystalline Fe(III) oxides and synthetic goethite-coated sand, a surrogate for a natural Fe(III)-coated material, using the component additivity (CA) approach. Our modeling results show that this model was able to describe U(VI) adsorption onto both amorphous and crystalline Fe(III) oxides and also goethite-coated sand quite well in the absence of phosphate. However, because phosphate adsorption exhibits a stronger dependence on Fe(III) oxide type than U(VI) adsorption, we could not use this model to consistently describe phosphate adsorption onto both amorphous and crystalline Fe(III) oxides and goethite-coated sand. However, the effects of phosphate on U(VI) adsorption could be incorporated into the model to describe U(VI) adsorption to both amorphous and crystalline Fe(III) oxides and goethite-coated sand, at least for an initial approximation. These results illustrate both the potential and limitations of using surface complexation models developed from pure systems to describe metal/radionuclide adsorption under more complex conditions. (orig.)

Surface complexation modeling of the effects of phosphate on uranium(VI) adsorption

International Nuclear Information System (INIS)

Romero-Gonzalez, M.R.; Cheng, T.; Barnett, M.O.; Roden, E.E.

2007-01-01

Previous published data for the adsorption of U(VI) and/or phosphate onto amorphous Fe(III) oxides (hydrous ferric oxide, HFO) and crystalline Fe(III) oxides (goethite) was examined. These data were then used to test the ability of a commonly-used surface complexation model (SCM) to describe the adsorption of U(VI) and phosphate onto pure amorphous and crystalline Fe(III) oxides and synthetic goethite-coated sand, a surrogate for a natural Fe(III)-coated material, using the component additivity (CA) approach. Our modeling results show that this model was able to describe U(VI) adsorption onto both amorphous and crystalline Fe(III) oxides and also goethite-coated sand quite well in the absence of phosphate. However, because phosphate adsorption exhibits a stronger dependence on Fe(III) oxide type than U(VI) adsorption, we could not use this model to consistently describe phosphate adsorption onto both amorphous and crystalline Fe(III) oxides and goethite-coated sand. However, the effects of phosphate on U(VI) adsorption could be incorporated into the model to describe U(VI) adsorption to both amorphous and crystalline Fe(III) oxides and goethite-coated sand, at least for an initial approximation. These results illustrate both the potential and limitations of using surface complexation models developed from pure systems to describe metal/radionuclide adsorption under more complex conditions. (orig.)

The Effects of Writing Anxiety and Motivation on EFL College Students' Self-Evaluative Judgments of Corrective Feedback.

Science.gov (United States)

Tsao, Jui-Jung; Tseng, Wen-Ta; Wang, Chaochang

2017-04-01

Feedback is regarded as a way to foster students' motivation and to ensure linguistic accuracy. However, mixed findings are reported in the research on written corrective feedback because of its multifaceted nature and its correlations with learners' individual differences. It is necessary, therefore, to conduct further research on corrective feedback from the student's perspective and to examine how individual differences in terms of factors such as writing anxiety and motivation predict learners' self-evaluative judgments of both teacher-corrected and peer-corrected feedback. For this study, 158 Taiwanese college sophomores participated in a survey that comprised three questionnaires. Results demonstrated that intrinsic motivation and different types of writing anxiety predicted English as foreign language learners' evaluative judgments of teacher and peer feedback. The findings have implications for English-writing instruction.

Individual energy use and feedback in an office setting: A field trial

International Nuclear Information System (INIS)

Murtagh, Niamh; Nati, Michele; Headley, William R.; Gatersleben, Birgitta; Gluhak, Alexander; Imran, Muhammad Ali; Uzzell, David

2013-01-01

Despite national plans to deploy smart meters in small and medium businesses in the UK, there is little knowledge of occupant energy use in offices. The objectives of the study were to investigate the effect of individual feedback on energy use at the workdesk, and to test the relationship between individual determinants, energy use and energy reduction. A field trial is presented, which monitored occupant energy use and provided individual feedback to 83 office workers in a university. The trial comprised pre- and post-intervention surveys, energy measurement and provision of feedback for 18 weeks post-baseline, and two participant focus groups. The main findings were: statistically significant energy reduction was found, but not for the entire measurement period; engagement with feedback diminished over time; no measured individual variables were related to energy reduction and only attitudes to energy conservation were related to energy use; an absence of motivation to undertake energy reduction actions was in evidence. The implications for energy use in offices are considered, including the need for motivations beyond energy reduction to be harnessed to realise the clear potential for reduced energy use at workdesks. -- Highlights: •First study on individual energy use and feedback in offices. •Field trial with 83 office workers, measuring plug load at desks over 18 weeks. •Feedback resulted in energy reduction although not consistently. •Sizeable minority did not engage with the feedback. •Lack of motivation to conserve energy evident in focus groups

Feedback-related brain activity predicts learning from feedback in multiple-choice testing.

Science.gov (United States)

Ernst, Benjamin; Steinhauser, Marco

2012-06-01

Different event-related potentials (ERPs) have been shown to correlate with learning from feedback in decision-making tasks and with learning in explicit memory tasks. In the present study, we investigated which ERPs predict learning from corrective feedback in a multiple-choice test, which combines elements from both paradigms. Participants worked through sets of multiple-choice items of a Swahili-German vocabulary task. Whereas the initial presentation of an item required the participants to guess the answer, corrective feedback could be used to learn the correct response. Initial analyses revealed that corrective feedback elicited components related to reinforcement learning (FRN), as well as to explicit memory processing (P300) and attention (early frontal positivity). However, only the P300 and early frontal positivity were positively correlated with successful learning from corrective feedback, whereas the FRN was even larger when learning failed. These results suggest that learning from corrective feedback crucially relies on explicit memory processing and attentional orienting to corrective feedback, rather than on reinforcement learning.

Modeling of kinetics of Cr(VI) sorption onto grape stalk waste in a stirred batch reactor

International Nuclear Information System (INIS)

Escudero, Carlos; Fiol, Nuria; Poch, Jordi; Villaescusa, Isabel

2009-01-01

Recently, Cr(VI) removal by grape stalks has been postulated to follow two mechanisms, adsorption and reduction to trivalent chromium. Nevertheless, the rate at which both processes take place and the possible simultaneity of both processes has not been investigated. In this work, kinetics of Cr(VI) sorption onto grape stalk waste has been studied. Experiments were carried out at different temperatures but at a constant pH (3 ± 0.1) in a stirred batch reactor. Results showed that three steps take place in the process of Cr(VI) sorption onto grape stalk waste: Cr(VI) sorption, Cr(VI) reduction to Cr(III) and the adsorption of the formed Cr(III). Taking into account the evidences above mentioned, a model has been developed to predict Cr(VI) sorption on grape stalks on the basis of (i) irreversible reduction of Cr(VI) to Cr(III) reaction, whose reaction rate is assumed to be proportional to the Cr(VI) concentration in solution and (ii) adsorption and desorption of Cr(VI) and formed Cr(III) assuming that all the processes follow Langmuir type kinetics. The proposed model fits successfully the kinetic data obtained at different temperatures and describes the kinetics profile of total, hexavalent and trivalent chromium. The proposed model would be helpful for researchers in the field of Cr(VI) biosorption to design and predict the performance of sorption processes.

Unpacking Student Feedback as a Basis for Metacognition and Mediated Learning Experiences: A Socio-cultural perspective

Directory of Open Access Journals (Sweden)

Edmore Mutekwe

2014-11-01

Full Text Available The study examines the effects of the feedback given to students by lecturers as learning support. It was conducted with undergraduates in an educational theory course in a South African university. The thesis was that although some of the feedback messages transmitted to students regarding strengths and weaknesses in learning get easily decoded and turned into action to improve performance, some messages are misconstrued by the students making the process of giving feedback complex. Data was collected through a cross-sectional feedback survey utilizing focus group interviews with 50 Bachelor of Education pre-service students conveniently sampled. The data analysis followed a thematic approach with superordinate themes used to structure the discussion of findings. The study found that student feedback needs to be culturally responsive for it to foster metacognition in them. The conclusion was that unless lecturers provide feedback that is simple, meaningful and clearly focused, students are unlikely to take much heed of it as there is a general tendency to focus more on the marks obtained than on the role of the feedback provided. This makes some students leave university under-prepared or half-baked in terms of providing student feedback on performance.

Biological detoxification of Cr(VI) using wood-husk immobilized Acinetobacter haemolyticus

International Nuclear Information System (INIS)

Zakaria, Zainul Akmar; Zakaria, Zainoha; Surif, Salmijah; Ahmad, Wan Azlina

2007-01-01

Acinetobacter haemolyticus, a Gram-negative aerobic locally isolated bacterium, immobilized on wood-husk showed the ability to detoxify Cr(VI) to Cr(III). Wood-husk, a natural cellulose-based support material, packed in an upward-flow column was used as support material for bacterial attachment. Around 97% of the Cr(VI) in wastewater containing 15 mg L -1 of Cr(VI) was reduced at a flow rate of 8.0 mL min -1 . The wastewater containing Cr(VI) was added with liquid pineapple wastewater as nutrient source for the bacteria. Electron microscopic examinations of the wood-husk after 42 days of column operation showed gradual colonization of the wood-husk by bacterial biofilm. The use of 0.1% (v/v) formaldehyde as a disinfecting agent inhibited growth of bacteria present in the final wastewater discharge. This finding is important in view of the ethical code regarding possible introduction of exogenous bacterial species into the environment

Biological detoxification of Cr(VI) using wood-husk immobilized Acinetobacter haemolyticus

Energy Technology Data Exchange (ETDEWEB)

Zakaria, Zainul Akmar; Zakaria, Zainoha [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Surif, Salmijah [Department of Environmental Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Ahmad, Wan Azlina [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia)], E-mail: azlina@kimia.fs.utm.my

2007-09-05

Acinetobacter haemolyticus, a Gram-negative aerobic locally isolated bacterium, immobilized on wood-husk showed the ability to detoxify Cr(VI) to Cr(III). Wood-husk, a natural cellulose-based support material, packed in an upward-flow column was used as support material for bacterial attachment. Around 97% of the Cr(VI) in wastewater containing 15 mg L{sup -1} of Cr(VI) was reduced at a flow rate of 8.0 mL min{sup -1}. The wastewater containing Cr(VI) was added with liquid pineapple wastewater as nutrient source for the bacteria. Electron microscopic examinations of the wood-husk after 42 days of column operation showed gradual colonization of the wood-husk by bacterial biofilm. The use of 0.1% (v/v) formaldehyde as a disinfecting agent inhibited growth of bacteria present in the final wastewater discharge. This finding is important in view of the ethical code regarding possible introduction of exogenous bacterial species into the environment.

Cr(VI) adsorption from electroplating plating wastewater by chemically modified coir pith.

Science.gov (United States)

Suksabye, Parinda; Thiravetyan, Paitip

2012-07-15

Coir pith samples were chemically modified by grafting with acrylic acid for the removal of Cr(VI) from electroplating wastewater. The presence of acrylic acid on the coir pith surface was verified by a scanning electron microscope with an electron dispersive x-ray spectrometer (SEM/EDX), Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TG). The carbonyl groups (C==O) from the carboxylic acids (COOH) increased on the coir pith surface after grafting with acrylic acid. In addition, the thermal stability of the acrylic acid-grafted coir pith also improved. The optimum conditions for grafting the acrylic acid on the coir pith consisted of 2 M acrylic acid and 0.00125 M ceric ammonium nitrate (CAN, as an initiator). The maximum Cr(VI) removal (99.99 ± 0.07%) was obtained with the following conditions: a 1.3% (w/v) dosage of acrylic acid-grafted coir pith, a system pH of 2, a contact time of 22 h, a temperature of 30 °C, a particle size of <150 μm and an initial Cr(VI) of 1,171 mg l(-1). At system pH of 2, Cr(VI) in the HCrO(4)(-) form can be adsorbed with acrylic acid-grafted coir pith via an electrostatic attraction. The adsorption isotherm of 2 M acrylic acid-grafted coir pith exhibited a good fit with the Langmuir isotherm. The maximum Cr(VI) adsorption capacity of the 2 M acrylic acid-grafted coir pith was 196.00 mg Cr(VI) g(-1) adsorbent, whereas for coir pith without grafting, the maximum Cr(VI) removal was 165.00 mg Cr(VI) g(-1) adsorbent. The adsorption capacity of the acrylic acid-grafted coir pith for Cr(VI) was higher compared to the original coir pith. This result was due to the enhancement of the carbonyl groups on the coir pith surface that may have involved the mechanism of chromium adsorption. The X-ray absorption near edged structure (XANES) and desorption studies suggested that most of the Cr(III) that presented on the acrylic acid-grafted coir pith was due to the Cr(VI) being reduced to Cr(III) on the adsorbent surface. FTIR

Formation of nitridotechnetium(VI) μ-oxo dimer complexes with EDTA and EDDA

International Nuclear Information System (INIS)

Takayama, T.; Kani, Y.; Sekine, T.; Kudo, H.; Yoshihara, K.

1995-01-01

Reactions of [ 99 TcNCl 4 ] - with ethylenediaminetetraacetic acid 4 (ETDA) and ethylenediamine-N,N'-diacetic acid (EDDA) in a mixture of water and acetone gave Tc VI N-EDTA and Tc VI N-EDTA complexes. The infrared spectra of both reaction products showed the existence of the Tc≡N and C=O groups. The elemental analysis indicated the 1:1 TcN-ligand ratio in the EDTA and EDDA complexes. Electrophoresis showed that the Tc VI -EDTA complex was an anionic species in a perchlorate solution. For the Tc VI N-EDDA complex, neutral and anionic species were formed, depending on the pH of the solution. Formation of the μ-oxo dimer complexes was suggested from the UV-Vis absorption spectra. (author) 11 refs.; 4 figs.; 1 tab

Study on Adsorption of Chromium (VI) by Activated Carbon from Cassava Sludge

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Yang, Jinhui; Li, Chuanshu; Yang, Bin; Kang, Sijun; Zhang, Zhen

2018-03-01

In this paper, a new type of adsorbent prepared by waste sludge from alcohol production industry was used to adsorb Cr (VI) in activated carbon from cassava sludge. A series of static adsorption experiments were carried out on the initial concentration of solution Cr (VI), pH value of solution, adsorption time and dosage of adsorbent. The results of single factor experiments show that the removal rate of Cr (VI) increases with the initial concentration of Cr(VI), while the adsorption amount is opposite. When the pH value of the solution is low, the adsorption effect of activated carbon is better.The adsorption time should be controlled within 40-60min. When the activated carbon dosage is increased, the removal rate increases but the adsorption capacity decreases.

An Analysis of School Principals' Listening Skills According to Teacher Feedback

Science.gov (United States)

Yavuz, Mustafa

2010-01-01

This study investigates school principals' listening skills according to teacher feedback in terms of a number of variables. The study is conducted according to a general survey model. The sample consists of 477 elementary, general and vocational secondary school teachers working in Konya, Turkey, in the 2007-2008 education year. The sample was…

Spectroscopic Studies on Complex Formation of U(VI)-thiosalicylate

Energy Technology Data Exchange (ETDEWEB)

Cha, Wan Sik; Cho, Hye Ryun; Park, Kyoung Kyun; Jung, Euo Chang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2011-05-15

The dynamic interaction between radionuclides and organic ligands is largely dependent on the composition of functional groups in a ligand chemical structure. Therefore, the structural mimics of natural ligands possessing specific functional groups, such as hydroxy, phenol, carboxyl, thiol and amine groups, have been studied to understand their influence on the migration of radionuclides including actinide species under geological groundwater conditions. In previous studies, we demonstrated that the fraction of hydrolyzed U(VI) species occurring in weak acidic solutions (pH {approx}4.5) is significantly influenced by the presence of salicylate (Sal) ligand due to the simultaneous participation of both phenol and carboxyl groups in the formation of U(VI)-complexes. Thiosalicylic acid (TSalH{sub 2}) is a good model compound for studying the effects of both carboxyl and thiol (-SH) groups. The fraction of di-anionic ligand form (TSal{sup 2-}) is higher at near neutral pH due to the lower pKa ({approx} 8) of the thiol group than the case of salicylic acid (pKa, {approx}13 for salicylic -OH), despite the structural similarity. In addition, the redox capability of the thiol group is expected to influence the reducible radiouclides and the chemical structures of natural ligands by creating cross-linkage (-S-S-) upon oxidation. The goal of the present study is to investigate aqueous U(VI)-TSal complexation equilibrium via laser-based spectroscopic techniques including time resolved laser-induced fluorescence spectroscopy (TRLFS). In this preliminary work, we report the results of spectroscopic studies using conventional UVVis absorbance and fluorescence (FL) measurement methods. The photo-stability of U(VI)-TSal complex or ligand itself upon exposure to a series of laser pulses is estimated by monitoring the change in their absorption bands. Additionally, TSal FL-quenching effect by U(VI) ions is discussed in comparison with that of Sal FL-quenching

Determination of chromium (VI) in primary and secondary fertilizer and their respective precursors.

Science.gov (United States)

Krüger, Oliver; Fiedler, Francesca; Adam, Christian; Vogel, Christian; Senz, Rainer

2017-09-01

Hexavalent chromium species (Cr(VI)) are often carcinogenic, of high acute toxicity, highly mobile, and thus pose a severe risk to health and environment. Fertilizers usually contain significant amounts of chromium. Therefore, a reliable analysis of chromium and the fraction of Cr(VI) are crucial for safe use of fertilizers. This problem is expected to increase in the future, since more and more recycled fertilizers emerge due to increasing fertilizer demand and respective supply risks. However, existing analytical methods have been developed for conventional fertilizers and have to be tested whether they are suitable for the new materials. Thus, we performed a wet-chemical extraction for Cr(VI) on several matrices as well as respective quality control experiments including spiking with Cr(III) and Cr(VI) compounds. We found the Cr(VI) amounts to be below 2 mg/kg except for a thermally post-treated sewage sludge ash (SSA) that showed 12.3 mg/kg. The presence of organic matter e.g. in sludge or precipitated struvite caused a reduction of spiked Cr(VI) and thus no satisfying recovery for quality control. Cr(VI) reduction was also observed for SSA, presumably due to the presence of Fe(II) compounds. Even though the tested procedure can be hampered in some recycled fertilizer matrices, it might be adapted to be applicable also for these complex samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Can iron oxides remove Cr(VI) from drinking water at sub-ppb levels?

Science.gov (United States)

Kaprara, Efthymia; Simeonidis, Konstantinos; Samaras, Petros; Zouboulis, Anastasios; Mitrakas, Manassis

2013-04-01

Hexavalent chromium [Cr(VI)] has long been recognized as a potential carcinogen via inhalation, in contrast to trivalent chromium [Cr(III)] which is 100 times less toxic and also a necessary nutrient, essential to human glucidic metabolism. Nowadays there is an increasing concern that Cr(VI) is also carcinogenic by the oral route of exposure, while an increased number of publications indicate that Cr(VI) is a common natural pollutant. Hexavalent chromium formation is attributed to natural oxidation of Cr(III) in ultramafic derived soils and ophiolithic rocks. To verify this theory, drinking water samples were collected from targeted areas of Greece e.g. areas in which the geological background is predominated by ultramafic minerals and the water supply depends mainly on groundwater resources. Valuable guide for the samples collection was the geological map of Greece and emphasis was given to regions where the natural occurrence of Cr(VI) is thought to be more possible. A wide range of Cr concentrations (2-100 μg/L) were detected in the areas studied, with most of them ranging below the current limit of 50 μg/L, and the Cr(VI) concentration being more than 90% of the total. Since the Cr(VI) affects significant part of population worldwide, a debate was established concerning the enforcement of stringent regulation, which also demands the drinking water treatment processes re-evaluation in view of Cr(VI) removal at sub-ppb level. In this regard, adsorption has evolved as the front line of defense for chromium removal. The motivation of this work was to investigate the efficiency of iron oxides for the adsorption of Cr(VI) from drinking water and its removal at sub-ppb levels. The adsorbents examined included iron oxy-hydroxides and magnetite prepared using common low cost iron salts. Their effectiveness as Cr(VI) adsorbents was evaluated through the decrease of a Cr(VI) concentration of 100μg/L prepared in NSF water at pH 7. Preliminary batch experiments did not

Does outcome feedback make you a better emergency physician? A systematic review and research framework proposal.

Science.gov (United States)

Lavoie, Curtis F; Schachter, Howard; Stewart, Aviva T; McGowan, Jessie

2009-11-01

The organization of emergency medical care limits the ability of emergency physicians to know the outcomes of most of their patients after the patients leave the emergency department. This lack of outcome feedback may hinder the practice of emergency medicine (EM) by preventing "calibration" of the decision tools of practitioners. We sought to determine what is currently known about outcome feedback in EM, including its incidence, impact and modifiers. We searched the following databases: PreMEDLINE, MEDLINE, EMBASE, CINAHL, CENTRAL, PsycINFO, DARE, Health Technology Assessment Database and AMED. We performed manual searches on abstract databases, reference lists, various health information and research websites, and nonindexed journals. Selection entailed a 2-step screening pro cess to exclude articles not pertaining to outcome feedback in EM. Our search yielded 1128 bibliographic records, from which screening identified 7 relevant reports: 5 surveys, 1 system level evaluation and 1 intervention trial. All studies were found to have "inadequate" or "unable to assess" reporting and study quality. Systems for outcome feedback to EM residents have been increasingly available since 1984, though they are perceived to be inadequate. Commonly used mechanisms for outcome feedback include automatic routing of discharge summaries, case conferences for admitted patients and telephone calls to patients or families for discharged patients. With respect to attending emergency physicians, no conclusions or clinical recommendations can be made given the level of available evidence. The potential importance of outcome feedback remains, at this time, underevaluated. We propose a research framework, and hypothesize that increasing outcome feedback would increase emergency physician diagnostic accuracy, therapeutic outcomes, clinical efficiency and job satisfaction. Future research in this area should include surveys and focus groups, as well as simulated or real-world intervention

Influence of chemical compositions and molecular weights of humic acids on Cr(VI) photo-reduction

International Nuclear Information System (INIS)

Chen, S.Y.; Huang, S.W.; Chiang, P.N.; Liu, J.C.; Kuan, W.H.; Huang, J.H.; Hung, J.T.; Tzou, Y.M.; Chen, C.C.; Wang, M.K.

2011-01-01

Highlights: ► Low molecular weights (M w ) of HA bear more polar and aromatic C in its structure. ► The polar sites of HA dominate the photo-reduction of Cr(VI). ► Low M w of HA exhibits greater photochemical efficiency for Cr(VI) reduction. ► Cr(VI) adsorption on HA is indiscernible, particularly on the small M w of HA. ► Upon Cr(VI) reduction by HA, most of Cr(III) are released into the solution. - Abstract: Humic acids (HA) strongly affect the fate of trace metals in soils and aquatic environments. One of the remarkable properties of HA is its ability to reduce Cr(VI), an extremely toxic anion. However, it is unclear which HA components are involved in Cr(VI) reduction and possess the photo-induced properties. In this study, an ultrafiltration technique was used to fractionate HAs into four fractions of different nominal molecular weights (M w ): >100, 50–100, 10–50 and w HA was enriched with polar and aromatic domains. These polar, including polar C in aliphatic region, and aromatic groups were the major sites for Cr(VI) reduction because they disappeared rapidly upon interaction with Cr(VI). As a result, low M w of HA exhibited greater efficiency of Cr(VI) reduction. Light induced the rapid transfer of electrons between chromate-phenol/carboxyl ester, or the formation of peroxide radicals or H 2 O 2 through the ready decay of peroxy radicals associated with polar substituents, explained the rapid scavenging of Cr(VI) on polar and aromatic groups of HAs under illumination.

Kinetics of Uranium(VI) Desorption from Contaminated Sediments: Effect of Geochemical Conditions and Model Evaluation

International Nuclear Information System (INIS)

Liu, Chongxuan; Shi, Zhenqing; Zachara, John M.

2009-01-01

Stirred-flow cell experiments were performed to investigate the kinetics of uranyl (U(VI)) desorption from a contaminated sediment collected from the Hanford 300 Area at the US Department of Energy (DOE) Hanford Site, Washington. Three influent solutions of variable pH, Ca and carbonate concentrations that affected U(VI) aqueous and surface speciation were used under dynamic flow conditions to evaluate the effect of geochemical conditions on the rate of U(VI) desorption. The measured rate of U(VI) desorption varied with solution chemical composition that evolved as a result of thermodynamic and kinetic interactions between the influent solutions and sediment. The solution chemical composition that led to a lower equilibrium U(VI) sorption to the solid phase yielded a faster desorption rate. The experimental results were used to evaluate a multi-rate, surface complexation model (SCM) that has been proposed to describe U(VI) desorption kinetics in the Hanford sediment that contained complex sorbed U(VI) species in mass transfer limited domains. The model was modified and supplemented by including multi-rate, ion exchange reactions to describe the geochemical interactions between the solutions and sediment. With the same set of model parameters, the modified model reasonably well described the evolution of major ions and the rates of U(VI) desorption under variable geochemical and flow conditions, implying that the multi-rate SCM is an effective way to describe U(VI) desorption kinetics in subsurface sediments

Characterization of Cr(VI) removal from aqueous solutions by a surplus agricultural waste-Rice straw

International Nuclear Information System (INIS)

Gao Hui; Liu Yunguo; Zeng Guangming; Xu Weihua; Li Ting; Xia Wenbin

2008-01-01

The removal of Cr(VI) from aqueous solution by rice straw, a surplus agricultural byproduct was investigated. The optimal pH was 2.0 and Cr(VI) removal rate increased with decreased Cr(VI) concentration and with increased temperature. Decrease in straw particle size led to an increase in Cr(VI) removal. Equilibrium was achieved in about 48 h under standard conditions, and Cr(III), which appeared in the solution and remained stable thereafter, indicating that both reduction and adsorption played a part in the Cr(VI) removal. The increase of the solution pH suggested that protons were needed for the Cr(VI) removal. A relatively high level of NO 3 - notably restrained the reduction of Cr(VI) to Cr(III), while high level of SO 4 2- supported it. The promotion of the tartaric acid modified rice straw (TARS) and the slight inhibition of the esterified rice straw (ERS) on Cr(VI) removal indicated that carboxyl groups present on the biomass played an important role in chromium remediation even though were not fully responsible for it. Isotherm tests showed that equilibrium sorption data were better represented by Langmuir model and the sorption capacity of rice straw was found to be 3.15 mg/g

Study of Cr(VI) adsorption onto magnetite nanoparticles using synchrotron-based X-ray absorption spectroscopy

Science.gov (United States)

Chen, Yen-Hua; Liu, Dian-Yu; Lee, Jyh-Fu

2018-04-01

In this study, the efficiency of Cr(VI) adsorption onto nano-magnetite was examined by batch experiments, and the Cr(VI) adsorption mechanism was investigated using synchrotron-based X-ray absorption spectroscopy. Magnetite nanoparticles with a mean diameter of 10 nm were synthesized using an inexpensive and simple co-precipitation method. It shows a saturation magnetization of 54.3 emu/g, which can be recovered with an external magnetic field. The adsorption data fitted the Langmuir adsorption isotherm well, implying a monolayer adsorption behavior of Cr(VI) onto nano-magnetite. X-ray absorption spectroscopy results indicate that the adsorption mechanism involves electron transfer between Fe(II) in nano-magnetite (Fe2+OFe3+ 2O3) and Cr(VI) to transform into Cr(III), which may exist as an Fe(III)-Cr(III) mixed solid phase. Moreover, the Cr(III)/Cr(VI) ratio in the final products can be determined by the characteristic pre-edge peak area of Cr(VI) in the Cr K-edge spectrum. These findings suggest that nano-magnetite is effective for Cr(VI) removal from wastewater because it can transform highly poisonous Cr(VI) species into nontoxic Cr(III) compounds, which are highly insoluble and immobile under environmental conditions.

Adsorption isotherm studies of chromium (VI) from aqueous solutions using sol-gel hydrotalcite-like compounds

Energy Technology Data Exchange (ETDEWEB)

Ramos-Ramirez, Esthela, E-mail: ramosre@quijote.ugto.mx [Centro de Investigaciones en Quimica Inorganica de la Universidad de Guanajuato, Noria Alta s/n, Col. Noria Alta, C.P. 36050, Guanajuato, Gto. (Mexico); Gutierrez Ortega, Norma L.; Conteras Soto, Cesar A. [Centro de Investigaciones en Quimica Inorganica de la Universidad de Guanajuato, Noria Alta s/n, Col. Noria Alta, C.P. 36050, Guanajuato, Gto. (Mexico); Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, km 36.5, La Marquesa, Coyoacan Mexico, C.P. 52750 (Mexico); Olguin Gutierrez, Maria T. [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, km 36.5, La Marquesa, Coyoacan Mexico, C.P. 52750 (Mexico)

2009-12-30

In under-developed countries, industries such as paint and pigment manufacturing, leather tanning, chrome plating and textile processing, usually discharge effluents containing Cr(VI) and Cr(III) into municipal sanitary sewers. It has been reported that Cr(VI) acts as a powerful epithelial irritant and as a human carcinogen. In the present work, hydrotalcite-like compounds with a Mg/Al ratio = 2 were synthesized by the sol-gel method. The hydrotalcite-like compounds and their corresponding thermally treated products were characterized by powder X-ray diffraction, infrared spectroscopy and N{sub 2} adsorption. The hydrotalcite-like compounds and the heated solids were used as adsorbents for Cr(VI) in aqueous solutions. Adsorption isotherm studies of Cr(VI) from aqueous solution are described. The adsorbent capacity was determined using the Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherm models. The Cr(VI) adsorption isotherm data fit best to the Langmuir isotherm model. The maximum Cr(VI) uptake by hydrotalcite and the heated solids was determined using the Langmuir equation and was found to range between 26 and 29 mg Cr(VI)/g adsorbent.

Adsorption isotherm studies of chromium (VI) from aqueous solutions using sol-gel hydrotalcite-like compounds

International Nuclear Information System (INIS)

Ramos-Ramirez, Esthela; Gutierrez Ortega, Norma L.; Conteras Soto, Cesar A.; Olguin Gutierrez, Maria T.

2009-01-01

In under-developed countries, industries such as paint and pigment manufacturing, leather tanning, chrome plating and textile processing, usually discharge effluents containing Cr(VI) and Cr(III) into municipal sanitary sewers. It has been reported that Cr(VI) acts as a powerful epithelial irritant and as a human carcinogen. In the present work, hydrotalcite-like compounds with a Mg/Al ratio = 2 were synthesized by the sol-gel method. The hydrotalcite-like compounds and their corresponding thermally treated products were characterized by powder X-ray diffraction, infrared spectroscopy and N 2 adsorption. The hydrotalcite-like compounds and the heated solids were used as adsorbents for Cr(VI) in aqueous solutions. Adsorption isotherm studies of Cr(VI) from aqueous solution are described. The adsorbent capacity was determined using the Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherm models. The Cr(VI) adsorption isotherm data fit best to the Langmuir isotherm model. The maximum Cr(VI) uptake by hydrotalcite and the heated solids was determined using the Langmuir equation and was found to range between 26 and 29 mg Cr(VI)/g adsorbent.

Adsorption isotherm studies of chromium (VI) from aqueous solutions using sol-gel hydrotalcite-like compounds.

Science.gov (United States)

Ramos-Ramírez, Esthela; Ortega, Norma L Gutiérrez; Soto, Cesar A Contreras; Gutiérrez, Maria T Olguín

2009-12-30

In under-developed countries, industries such as paint and pigment manufacturing, leather tanning, chrome plating and textile processing, usually discharge effluents containing Cr(VI) and Cr(III) into municipal sanitary sewers. It has been reported that Cr(VI) acts as a powerful epithelial irritant and as a human carcinogen. In the present work, hydrotalcite-like compounds with a Mg/Al ratio=2 were synthesized by the sol-gel method. The hydrotalcite-like compounds and their corresponding thermally treated products were characterized by powder X-ray diffraction, infrared spectroscopy and N(2) adsorption. The hydrotalcite-like compounds and the heated solids were used as adsorbents for Cr(VI) in aqueous solutions. Adsorption isotherm studies of Cr(VI) from aqueous solution are described. The adsorbent capacity was determined using the Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherm models. The Cr(VI) adsorption isotherm data fit best to the Langmuir isotherm model. The maximum Cr(VI) uptake by hydrotalcite and the heated solids was determined using the Langmuir equation and was found to range between 26 and 29 mg Cr(VI)/g adsorbent.

A kinetic study of biological Cr(VI) reduction in trickling filters with different filter media types

International Nuclear Information System (INIS)

Dermou, E.; Vayenas, D.V.

2007-01-01

Two pilot-scale trickling filters were used in order to estimate Cr(VI) reduction through biological mechanisms in biofilm reactors operated in SBR mode with recirculation using different filter media types, i.e. plastic media and calcitic gravel. The feed concentrations of Cr(VI) examined were about 5, 10, 20, 30, 50 and 100 mg/l, while the concentration of the organic carbon was constant at 400 mg/l, in order to avoid carbon limitations in the bulk liquid. Maximum reduction rates of 4.8 and 4.7 g Cr(VI)/d were observed for feed Cr(VI) concentration of about 5 mg Cr(VI)/l, for the filters with the plastic support material and the gravel media, respectively. The reduction rates were significantly affected by the feed Cr(VI) concentration in both bioreactors. A dual-enzyme kinetic model was used in order to describe Cr(VI) reduction by aerobically grown mixed cultures. Model predictions were found to correspond very closely to experimental quantitative observations of Cr(VI) reduction at both pilot-scale trickling filters used

Student Engagement with Feedback

Science.gov (United States)

Scott, Jon; Shields, Cathy; Gardner, James; Hancock, Alysoun; Nutt, Alex

2011-01-01

This report considers Biological Sciences students' perceptions of feedback, compared with those of the University as a whole, this includes what forms of feedback were considered most useful and how feedback used. Compared with data from previous studies, Biological Sciences students gave much greater recognition to oral feedback, placing it on a…

A Green Microbial Fuel Cell-Based Biosensor for In Situ Chromium (VI) Measurement in Electroplating Wastewater.

Science.gov (United States)

Wu, Li-Chun; Tsai, Teh-Hua; Liu, Man-Hai; Kuo, Jui-Ling; Chang, Yung-Chu; Chung, Ying-Chien

2017-10-27

The extensive use of Cr(VI) in many industries and the disposal of Cr(VI)-containing wastes have resulted in Cr(VI)-induced environmental contamination. Cr(VI) compounds are associated with increased cancer risks; hence, the detection of toxic Cr(VI) compounds is crucial. Various methods have been developed for Cr(VI) measurement, but they are often conducted offsite and cannot provide real-time toxicity monitoring. A microbial fuel cell (MFC) is an eco-friendly and self-sustaining device that has great potential as a biosensor for in situ Cr(VI) measurement, especially for wastewater generated from different electroplating units. In this study, Exiguobacterium aestuarii YC211, a facultatively anaerobic, Cr(VI)-reducing, salt-tolerant, and exoelectrogenic bacterium, was isolated and inoculated into an MFC to evaluate its feasibility as a Cr(VI) biosensor. The Cr(VI) removal efficiency of E. aestuarii YC211 was not affected by the surrounding environment (pH 5-9, 20-35 °C, coexisting ions, and salinity of 0-15 g/L). The maximum power density of the MFC biosensor was 98.3 ± 1.5 mW/m² at 1500 Ω. A good linear relationship ( r ² = 0.997) was observed between the Cr(VI) concentration (2.5-60 mg/L) and the voltage output. The developed MFC biosensor is a simple device that can accurately measure Cr(VI) concentrations in the actual electroplating wastewater that is generated from different electroplating units within 30 min with low deviations (-6.1% to 2.2%). After treating the actual electroplating wastewater with the MFC, the predominant family in the biofilm was found to be Bacillaceae (95.3%) and was further identified as the originally inoculated E. aestuarii YC211 by next generation sequencing (NGS). Thus, the MFC biosensor can measure Cr(VI) concentrations in situ in the effluents from different electroplating units, and it can potentially help in preventing the violation of effluent regulations.

Derivative spectrophotometric determination of trace amounts of Tungsten(VI) in real water samples

International Nuclear Information System (INIS)

Viswanatha, C.; Ramakrishna Reddy, K.; Devanna, N.; Praveen Kumar, M.D.

2012-01-01

2,4-Dimethoxybenzaldehydeisonicotinoylhydrazone (DMBHIH) has been synthesized and characterized with IR, NMR and Mass Spectroscopic methods. A simple and derivative spectrophotometric method has been developed for the determination of trace amounts of W(VI). The reagent forms a yellow coloured water soluble complex with W(VI) in basic medium (pH 8.0). The molar absorptivity and Sandell's sensitivity of coloured species are 3.43 x 10 4 L.mol -1 cm -1 and 0.0049 μg/cm 2 respectively. Beer's law is obeyed in the range 0.4113-6.2138 μg/ml of W(VI) at λ max 394 nm. W(VI) forms 1:1 complex with DMBHIH and stability constant of the complex was 5.22x10 6 . The first and second derivative amplitude was measured at 453 nm and 468 nm. The developed method applied for the determination of W(VI) in alloys and biological samples. (author)

Complex formation between glutamic acid and molybdenum (VI)

International Nuclear Information System (INIS)

Gharib, Farrokh; Khorrami, S.A.; Sharifi, Sasan

1997-01-01

Equilibria of the reaction of molybdenum (VI) with L-glutamic acid have been studied in aqueous solution in the pH range 2.5 to 9.5, using spectrophotometric and optical rotation methods at constant ionic strength (0.15 mol dm -3 sodium perchlorate) and temperature 25 ± 0.1 degC. Our studies have shown that glutamic acid forms a mononuclear complex with Mo(VI) of the type MoO 3 L 2- at pH 5.5. The stability constant of this complexation and the dissociation constants of L-glutamic acid have been determined. (author). 17 refs., 2 figs., 4 tabs

Thermophysical Properties of Selected II-VI Semiconducting Melts

Science.gov (United States)

Li, C.; Su, Ching-Hua; Lehoczky, S. L.; Scripa, R. N.; Ban, H.; Lin, B.

2004-01-01

Thermophysical properties are essential for the accurate predication of the crystal growth process by computational modeling. Currently, the temperature dependent thermophysical property data for the II-VI semiconductor melts are scarce. This paper reports the results of the temperature dependence of melt density, viscosity and electrical conductivity of selected II-VI compounds, including HgTe, HgCdTe and HgZnTe. The melt density was measured using a pycnometric method, and the viscosity and electrical conductivity were measured by a transient torque method. The results were compared with and showed good agreement with the existing data in the literature.

Negative Feedback for Small Capacitive Touchscreen Interfaces: A Usability Study for Data Entry Tasks.

Science.gov (United States)

Parikh, S P; Esposito, J M

2012-01-01

Touchscreen technology has become pervasive in the consumer product arena over the last decade, offering some distinct advantages such as software reconfigurable interfaces and the removal of space consuming mice and keyboards. However, there are significant drawbacks to these devices that have limited their adoption by some users. Most notably, standard touchscreens demand the user's visual attention and require them to look at the input device to avoid pressing the wrong button. This issue is particularly important for mobile, capacitive sensing, nonstylus devices, such as the iPhone where small button sizes can generate high error rates. While previous work has shown the benefits of augmenting such interfaces with audio or vibrotactile feedback, only positive feedback (confirmation of button presses) has been considered. In this paper, we present a simple prototype interface that provides negative vibrotactile feedback. By negative, we mean feedback is generated when an inactive or ambiguous part of the screen, such as the area between two buttons, is touched. First, we present a usability study comparing positive and negative vibrotactile feedback for a benchmark numerical data entry task. The difference in performance is not statistically significant, implying negative feedback provides comparable benefits. Next, based on the experimenter's observations and the users comments, we introduce a multimodal feedback strategy-combining complementary positive audio and negative vibrotactile signals. User tests on a text entry experiment show that, with multimodal feedback, users exhibit a (statistically significant) 24 percent reduction in corrective key presses, as compared to positive audio feedback alone. Exit survey comments indicate that users favor multimodal feedback.

Thermodynamic parameters and sorption of U(VI) on ACSD

International Nuclear Information System (INIS)

Donat, R.; Cilgi, G.K.; Cetisli, H.; Aytas, S.

2009-01-01

This paper discusses the sorption properties for U(VI) by alginate coated CaSO 4 x 2H 2 O sepiolite and calcined diatomite earth (Kieselguhr) (ACSD). The removal of U(VI) from aqueous solution by sorption onto ACSF in a single component system with various contact times, pH, temperatures, and initial concentrations of U(VI) was investigated. The sorption patterns of uranium on the composite adsorbent followed the Langmuir, Freundlich and Dubinin-Radushkhevic (D-R) isotherms. The Freundlich, Langmuir, and D-R models have been applied and the data correlated well with Freundlich model and that the sorption was physical in nature (sorption energy, E a = 17.05 kJ/mol). The thermodynamic parameters such as variation of enthalpy ΔH, variation of entropy ΔS and variation of Gibbs free energy ΔG were calculated from the slope and intercept of lnK 0 vs. 1/T plots. Thermodynamic parameters (ΔH ads = 31.83 kJ/mol, ΔS ads = 167 J/mol x K, ΔGdeg ads (293.15 K) = -17.94 kJ/mol) showed the endothermic heat of sorption and the feasibility of the process. The thermodynamics of U(VI) ion/ACSD system indicates the spontaneous and endothermic nature of the process. It was noted that an increase in temperature resulted in a higher uranium loading per unit weight of the adsorbent. (author)

Adsorption behavior and mechanism of Cr(VI) using Sakura waste from aqueous solution

International Nuclear Information System (INIS)

Qi, Wenfang; Zhao, Yingxin; Zheng, Xinyi; Ji, Min; Zhang, Zhenya

2016-01-01

Graphical abstract: The main chemical components of Sakura leaves are cellulose 16.6%, hemicellulose 10.4%, lignin 18.3%, ash 11.4%, and others 43.3%. The adsorption capacity of Cr(VI) onto Sakura leaves can achieve 435.25 mg g"−"1, much higher than other similar agroforestry wastes. - Highlights: • Sakura leaves were prepared to remove Cr(VI) from aqueous solution. • The maximum adsorption capacity of Cr(VI) reached 435.25 mg g"−"1. • Cr(VI) adsorption fitted pseudo-second-order kinetic model. • Isotherm models indicated Cr(VI) adsorption occurred on a monolayer surface. • The influence order of coexisting ions followed PO_4"3"− > SO_4"2"− > Cl"−. - Abstract: A forestall waste, Sakura leave, has been studied for the adsorption of Cr(VI) from aqueous solution. The materials before and after adsorption were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). To investigate the adsorption performance of Sakura waste, batch experiments were conducted under different adsorbent dosage, contact time, initial concentration of Cr(VI), and co-existing ions. Results showed the data fitted pseudo-second-order better than pseudo-first-order kinetic model. Equilibrium data was analyzed with Langmuir, Freundlich and Redlich–Peterson isotherm models at temperature ranges from 25 °C to 45 °C. The maximum adsorption capacity from the Langmuir model was 435.25 mg g"−"1 at pH 1.0. The presence of Cl"−, SO_4"2"− and PO_4"3"− would lead to an obvious negative effect on Cr(VI) adsorption, and their influence order follows PO_4"3"− > SO_4"2"− > Cl"−. The study developed a new way to reutilize wastes and showed a great potential for resource recycling.

Study on the DNA-protein crosslinks induced by chromium (VI) in SPC-A1

Science.gov (United States)

Liu, Yanqun; Ding, Jianjun; Lu, Xiongbing; You, Hao

2018-01-01

Objective: This study was designed to investigate the effect of chromium (VI) on DNA-protein crosslinks (DPC) of SPC-A1 cells. Methods: We exposed SPC-A1 cells were cultured in 1640 medium and treated with the SPC-A1 cells in vitro to different concentrations of Hexavalent chromium Cr(VI) for 2h, the KC1-SDS precipitation assay were used to measure the DNA-protein cross-linking effect. Results: All the different concentrations of Cr(VI) could cause the increase of DPC coefficient in SPC-A1 cells. But this effect was not significant (P>0.05) at low concentrations; while in high concentration Cr(VI) induced SPC-A1 cells could produce DNA-protein cross-linking effect significantly (P<0.05). Conclusions: chromium (VI) could induce DNA-protein crosslink.

Moving mesh finite element method for finite time extinction of distributed parameter systems with positive exponential feedback; Lokakarya Komputasi dalam Sains dan Teknologi Nuklir VI

Energy Technology Data Exchange (ETDEWEB)

Garnadi, A D [Department of Matematics, Bogor Institute of Agriculture, Bogor (Indonesia)

1997-07-01

In the distributed parameter systems with exponential feedback, non-global existence of solution is not always exist. For some positive initial values, there exist finite time T such that the solution goes to infinity, i.e. finite time extinction or blow-up. Here is present a numerical solution using Moving Mesh Finite Element to solve the distributed parameter systems with exponential feedback close to blow-up time. The numerical behavior of the mesh close to the time of extinction is the prime interest in this study.

Feedback i matematik

DEFF Research Database (Denmark)

Sortkær, Bent

2017-01-01

Feedback bliver i litteraturen igen og igen fremhævet som et af de mest effektive midler til at fremme elevers præstationer i skolen (Hartberg, Dobson, & Gran, 2012; Hattie & Timperley, 2007; Wiliam, 2015). Dette på trods af, at flere forskere påpeger, at feedback ikke altid er læringsfremmende...... (Hattie & Gan, 2011), og nogle endda viser, at feedback kan have en negativ virkning i forhold til præstationer (Kluger & DeNisi, 1996). Artiklen vil undersøge disse tilsyneladende modstridende resultater ved at stille spørgsmålet: Under hvilke forudsætninger virker feedback i matematik læringsfremmende......? Dette gøres ved at dykke ned i forskningslitteraturen omhandlende feedback ud fra en række temaer for på den måde at besvare ovenstående spørgsmål....

Inhibition of bone resorption by Tanshinone VI isolated from Salvia miltiorrhiza Bunge

Directory of Open Access Journals (Sweden)

V. Nicolin

2010-05-01

Full Text Available During the last decade, a more detailed knowledge of molecular mechanisms involved in osteoclastogenesis has driven research efforts in the development and screening of compound libraries of several small molecules that specifically inhibit the pathway involved in the commitment of the osteoclast precursor cells. Natural compounds that suppress osteoclast differentiation may have therapeutic value in treating osteoporosis and other bone erosive diseases such as rheumatoid arthritis or metastasis associated with bone loss. In ongoing investigation into anti-osteoporotic compounds from natural products we have analyzed the effect of Tanshinone VI on osteoclasts differentiation, using a physiologic three-dimensional osteoblast/bone marrow model of cell co-culture. Tanshinone VI is an abietane diterpene extracted from the root of Salvia miltiorrhiza Bunge (Labiatae, a Chinese traditional crude drug, ‘’Tan-Shen’’. Tashinone has been widely used in clinical practice for the prevention of cardiac diseases, arthritis and other inflammation-related disorders based on its pharmacological actions in multiple tissues. Although Tanshinone VI A has been used as a medicinal agent in the treatment of many diseases, its role in osteoclast-related bone diseases remains unknown. We showed previously that Tanshinone VI greatly inhibits osteoclast differentiation and suppresses bone resorption through disruption of the actin ring; subsequently, we intended to examine the precise inhibitory mechanism of Tanshinone VI on osteoclast differentiating factor. This study shows, for the first time, that Tanshinone VI prevents osteoclast differentiation by inhibiting RANKL expression and NFkB induction.

Oxidation of indometacin by ferrate (VI): kinetics, degradation pathways, and toxicity assessment.

Science.gov (United States)

Huang, Junlei; Wang, Yahui; Liu, Guoguang; Chen, Ping; Wang, Fengliang; Ma, Jingshuai; Li, Fuhua; Liu, Haijin; Lv, Wenying

2017-04-01

The oxidation of indometacin (IDM) by ferrate(VI) (Fe(VI)) was investigated to determine the reaction kinetics, transformation products, and changes in toxicity. The reaction between IDM and Fe(VI) followed first-order kinetics with respect to each reactant. The apparent second-order rate constants (k app ) decreased from 9.35 to 6.52 M -1  s -1 , as the pH of the solution increased from 7.0 to 10.0. The pH dependence of k app might be well explained by considering the species-specific rate constants of the reactions of IDM with Fe(VI). Detailed product studies using liquid chromatography-tandem mass spectrometry (LC-MS/MS) indicated that the oxidation products were primarily derived from the hydrolysis of amide linkages, the addition of hydroxyl groups, and electrophilic oxidation. The toxicity of the oxidation products was evaluated using the Microtox test, which indicated that transformation products exhibited less toxicity to the Vibrio fischeri bacteria. Quantitative structure-activity relationship (QSAR) analysis calculated by the ecological structure activity relationship (ECOSAR) revealed that all of the identified products exhibited lower acute and chronic toxicity than the parent pharmaceutical for fish, daphnid, and green algae. Furthermore, Fe(VI) was effective in the degradation IDM in water containing carbonate ions or fulvic acid (FA), and in lake water samples; however, higher Fe(VI) dosages would be required to completely remove IDM in lake water in contrast to deionized water.

Liquid-liquid extraction and separation studies of uranium(VI)

International Nuclear Information System (INIS)

Langade, A.D.; Shinde, V.M.

1980-01-01

Separation of uranium(VI) from iron(III), molybdenum(VI), vanadium(V), bismuth(III), zirconium(IV) and thorium(IV) is achieved by liquid-liquid extraction with 4-methyl-3-pentene-2-one (mesityl oxide; MeO) from sodium salicylate media (0.1M, pH 6.0). The extracted species is UO 2 (HO.C 6 H 4 COO) 2 .2MeO. A procedure for separating 50 μg of uranium from mg amounts of the other metals is described. (author)

Perceptions of Feedback One Year on: A Comparative Study of the Views of First and Second Year Biological Sciences Students

Science.gov (United States)

Scott, Jon; Badge, Jo; Cann, Alan

2009-01-01

The results are presented of a survey comparing the perceptions of first and second year bioscience students regarding their experience of feedback on coursework. The two cohorts displayed similar levels of satisfaction regarding the quantity and timing of feedback, even though changes in assessment format entailed different actual experiences. By…

Vi mangler endnu et panel

DEFF Research Database (Denmark)

Ritter, Thomas

2016-01-01

Vi mangler højtuddannede værdiskabere, som transformerer gode idéer og teknologier til indtjening og velstand. Først i mødet med markedet afgøres fremtiden. Troels Lund Poulsen bør nedsætte et kommercialiseringspanel, der byder ind med løsninger, hvordan Danmark bliver et land ikke kun med gode...

Spectrophotometric study of the complexation equilibria of uranium(VI) with 1,4-bis(4'-methylanilino)anthraquinone and determination of uranium(VI)

International Nuclear Information System (INIS)

Idriss, K.A.; Seleim, M.M.; Abu-Bakr, M.S.; Sedaira, H.

1985-01-01

The reaction of U(VI) with 1,4-bis(4'-methylanilino)anthraquinone (quinizarin green) in water-dimethylformamide medium was investigated spectrophotometrically. The complexation equilibria in solution were demonstrated. The study of the reaction in presence of equimolar concentrations or in solutions containing metal or ligand excess gave evidence for the formation of complexes with stoichiometric ratios of UO 2 :L = 1:1 and 1:2 in dependence on the pH of the medium. Their thermodynamic stabilities and the values of their molar absorption coefficients were determined. The optimum conditions for spectrophotometric determination of U(VI) with this reagent were found. (author)

Influence of radiolytic products on the chemistry of uranium VI in brines

International Nuclear Information System (INIS)

Lucchini, J-F.; Reed, D.T.; Borkowski, M.; Rafalski, A.; Conca, J.

2004-01-01

In the near field of a salt repository of nuclear waste, ionizing radiations can strongly affect the chemistry of concentrated saline solutions. Radiolysis can locally modify the redox conditions, speciation, solubility and mobility of the actinide compounds. In the case of uranium VI, radiolytic products can not only reduce U(VI), but also react with uranium species. The net effect on the speciation of uranyl depends on the relative kinetics of the reactions and the buildup of molecular products in brine solutions. The most important molecular products in brines are expected to be hypochlorite ion, hypochlorous acid and hydrogen peroxide. Although U(VI) is expected not to be significantly affected by radiolysis, the combined effects of the major molecular radiolytic products on the chemistry of U(VI) in brines have not been experimentally established previously. (authors)

Unconstrained steps of myosin VI appear longest among known molecular motors.

Science.gov (United States)

Ali, M Yusuf; Homma, Kazuaki; Iwane, Atsuko Hikikoshi; Adachi, Kengo; Itoh, Hiroyasu; Kinosita, Kazuhiko; Yanagida, Toshio; Ikebe, Mitsuo

2004-06-01

Myosin VI is a two-headed molecular motor that moves along an actin filament in the direction opposite to most other myosins. Previously, a single myosin VI molecule has been shown to proceed with steps that are large compared to its neck size: either it walks by somehow extending its neck or one head slides along actin for a long distance before the other head lands. To inquire into these and other possible mechanism of motility, we suspended an actin filament between two plastic beads, and let a single myosin VI molecule carrying a bead duplex move along the actin. This configuration, unlike previous studies, allows unconstrained rotation of myosin VI around the right-handed double helix of actin. Myosin VI moved almost straight or as a right-handed spiral with a pitch of several micrometers, indicating that the molecule walks with strides slightly longer than the actin helical repeat of 36 nm. The large steps without much rotation suggest kinesin-type walking with extended and flexible necks, but how to move forward with flexible necks, even under a backward load, is not clear. As an answer, we propose that a conformational change in the lifted head would facilitate landing on a forward, rather than backward, site. This mechanism may underlie stepping of all two-headed molecular motors including kinesin and myosin V.

Improving Teach Astronomy: A Survey of Instructors

Science.gov (United States)

Wenger, Matthew; Riabokin, Malanka; Impey, Chris David

2018-01-01

Teach Astronomy is a website that provides educational resources for introductory astronomy. The motivation behind constructing this site was to provide quality online educational tools for use as a primary or supplementary instructional resource for teachers and students. The website provides an online textbook, glossary, podcasts and video summaries of concepts. As the popularity of online courses steadily increases, so does the demand for robust online educational resources. In order to cater to our users, our team conducted a survey of the instructors that use Teach Astronomy site for feedback for use in updating and streamlining the website content. The survey collected feedback regarding functionality of each of the website tools, in which courses the site was being used, and the motivation of the instructors use of our site. The overwhelming majority of responses indicate that instructors use the website as a class textbook in introductory astronomy courses for non-science majors, and instructors also generally tended to agree that the site content was comprehensive and lucid. One interesting result of the survey is to cluster topics in a way that is consistent with different levels of instruction (i.e. grouping middle-school level content and university level content distinctly). Our team will use this feedback to improve the Teach Astronomy website and maintain it as a high-quality, free online resource. We will also continue to gather feedback from instructors to ensure that the Teach Astronomy website stays current and remains a valuable online resource for instructors around the country.