Safety and immunogenicity of a Vi-DT typhoid conjugate vaccine: Phase I trial in Healthy Filipino adults and children.

PubMed

Capeding, Maria Rosario; Teshome, Samuel; Saluja, Tarun; Syed, Khalid Ali; Kim, Deok Ryun; Park, Ju Yeon; Yang, Jae Seung; Kim, Yang Hee; Park, Jiwook; Jo, Sue-Kyoung; Chon, Yun; Kothari, Sudeep; Yang, Seon-Young; Ham, Dong Soo; Ryu, Ji Hwa; Hwang, Hee-Seong; Mun, Ju-Hwan; Lynch, Julia A; Kim, Jerome H; Kim, Hun; Excler, Jean-Louis; Sahastrabuddhe, Sushant

2018-06-18

Typhoid fever remains a major public health problem in low- and middle-income countries where children aged 2-14 years bear the greatest burden. Vi polysaccharide is poorly immunogenic in children <2 years of age, and protection in adults is modest. The limitations of Vi polysaccharide vaccines can be overcome by conjugation of the Vi to a carrier protein. A typhoid conjugate vaccine composed of Vi polysaccharide conjugated to diphtheria toxoid (Vi-DT) has been developed. The Phase I study results are presented here. This was a randomized, observer-blinded Phase I study to assess the safety and immunogenicity of Vi-DT compared to Vi polysaccharide vaccine, conducted in Manila, Philippines. Participants enrolled in an age de-escalation manner (18-45, 6-17 and 2-5 years) were randomized between Test (Vi-DT, 25 µg) administered at 0 and 4 weeks and Comparator (Vi polysaccharide, Typhim Vi® and Vaxigrip®, Sanofi Pasteur) vaccines. A total of 144 participants were enrolled (48 by age strata, 24 in Test and Comparator groups each). No serious adverse event was reported in either group. Solicited and unsolicited adverse events were mild or moderate in both groups with the exception of a 4-year old girl in Test group with grade 3 fever which resolved without sequelae. All participants in Test group seroconverted after first and second doses of Vi-DT while the proportions in the Comparator group were 97.1% and 97.2%, after first dose of Typhim Vi® and second dose of Vaxigrip®, respectively. Vi-DT showed 4-fold higher Geometric Mean Titers (GMT) compared to Typhim Vi® (adjusted for age strata, p < 0.001). No further increase of GMT was detected after the second dose of Vi-DT. Anti-DT IgG seroresponse rates were 81.2% and 84.5% post first and second Vi-DT doses, respectively. Vi-DT vaccine was safe, well-tolerated and immunogenic in participants aged 2-45 years. ClinicalTrials.gov registration number: NCT02645032. Copyright © 2018 The Authors. Published

Analysis and characterization of the vertical wind profile in UAE

NASA Astrophysics Data System (ADS)

Lee, W.; Ghedira, H.; Ouarda, T.; Gherboudj, I.

2011-12-01

In this study, temporal and spatial analysis of the vertical wind profiles in the UAE has been performed to estimate wind resource potential. Due to the very limited number of wind masts (only two wind masts in the UAE, operational for less than three years), the wind potential analysis will be mainly derived from numerical-based models. Additional wind data will be derived from the UAE met stations network (at 10 m elevation) managed by the UAE National Center of Meteorology and Seismology. However, since wind turbines are generally installed at elevations higher than 80 m, it is vital to extrapolate wind speed correctly from low heights to wind turbine hub heights to predict potential wind energy properly. To do so, firstly two boundary layer based models, power law and logarithmic law, were tested to find the best fitting model. Power law is expressed as v/v0 =(H/H0)^α and logarithmic law is represented as v/v0 =[ln(H/Z0))/(ln(H0/Z0)], where V is the wind speed [m/s] at height H [m] and V0 is the known wind speed at a reference height H0. The exponent (α) coefficient is an empirically derived value depending on the atmospheric stability and z0 is the roughness coefficient length [m] that depends on topography, land roughness and spacing. After testing the two models, spatial and temporal analysis for wind profile was performed. Many studies about wind in different regions have shown that wind profile parameters have hourly, monthly and seasonal variations. Therefore, it can be examined whether UAE wind characteristics follow general wind characteristics observed in other regions or have specific wind features due to its regional condition. About 3 years data from August 2008 to February 2011 with 10-minutes resolution were used to derive monthly variation. The preliminary results(Fig.1) show that during that period, wind profile parameters like alpha from power law and roughness length from logarithmic law have monthly variation. Both alpha and roughness have

The United Arab Emirates (UAE): Issues for U.S. Policy

DTIC Science & Technology

2010-12-07

tallest building, on January 4, 2010. Dubai metro has begun operations and is expanding service. Burj al Arab hotel in Dubai bills itself as “world’s...CRS Report for Congress Prepared for Members and Committees of Congress The United Arab Emirates (UAE): Issues for U.S. Policy Kenneth...3. DATES COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE The United Arab Emirates (UAE): Issues for U.S. Policy 5a. CONTRACT NUMBER

Tropospheric Enhancement of Ozone over the UAE

NASA Astrophysics Data System (ADS)

Abbasi, Naveed Ali; Majeed, Tariq; Iqbal, Mazhar; Kaminski, Jacek; Struzewska, Joanna; Durka, Pawel; Tarasick, David; Davies, Jonathan

2015-04-01

We use the Global Environmental Multiscale - Air Quality (GEM-AQ) model to interpret the vertical profiles of ozone acquired with ozone sounding experiments at the meteorological site located at the Abu Dhabi airport. The purpose of this study is to gain insight into the chemical and dynamical structures in the atmosphere of this unique subtropical location (latitude 24.45N; longitude 54.22E). Ozone observations for years 2012 - 2013 reveal elevated ozone abundances in the range from 70 ppbv to 120 ppbv near 500-400 hPa during summer. The ozone abundances in other seasons are much lower than these values. The preliminary results indicate that summertime enhancement in ozone is associated with the Arabian anticyclones centered over the Zagros Mountains in Iran and the Asir and Hijaz Mountain ranges in Saudi Arabia, and is consistent with TES observations of deuterated water. The model also shows considerable seasonal variation in the tropospheric ozone which is transported from the stratosphere by dynamical processes. The domestic production of ozone in the middle troposphere is estimated and compared GEM-AQ model. It is estimated that about 40-50% of ozone in the UAE is transported from the neighbouring petrochemical industries in the Gulf region. We will present ozone sounding data and GEM-AQ results including a discussion on the high levels of the tropospheric ozone responsible for contaminating the air quality in the UAE. This work is supported by National Research Foundation, UAE.

Rheology of water ices V and VI

USGS Publications Warehouse

Durham, W.B.; Stern, L.A.; Kirby, S.H.

1996-01-01

We have measured the mechanical strength (??) of pure water ices V and VI under steady state deformation conditions. Constant displacement rate compressional tests were conducted in a gas apparatus at confining pressures from 400 250 K. Ices V and VI are thus Theologically distinct but by coincidence have approximately the same strength under the conditions chosen for these experiments. To avoid misidentification, these tests are therefore accompanied by careful observations of the occurrences and characteristics of phase changes. One sample each of ice V and VI was quenched at pressure to metastably retain the high-pressure phase and the acquired deformation microstructures; X ray diffraction analysis of these samples confirmed the phase identification. Surface replicas of the deformed and quenched samples suggest that ice V probably deforms largely by dislocation creep, while ice VI deforms by a more complicated process involving substantial grain size reduction through recrystallization.

What Makes the UAE a Knowledge Society?

ERIC Educational Resources Information Center

Assaf, Mohammad Ahmad

2011-01-01

This paper starts with the idea that knowledge has become one of the most important factors to determine human development and explore the different requirements that need to be met by the government and the citizens of the UAE to succeed in building a knowledge society (KS). An explanation and examination of the five pillars of establishing a KS…

Microstructural analyses of Cr(VI) speciation in chromite ore processing Residue (COPR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

CHRYSOCHOOU, MARIA; FAKRA, SIRINE C .; Marcus, Matthew A.

2010-03-01

The speciation and distribution of Cr(VI) in the solid phase was investigated for two types of chromite ore processing residue (COPR) found at two deposition sites in the United States: gray-black (GB) granular and hard brown (HB) cemented COPR. COPR chemistry and mineralogy were investigated using micro-X-ray absorption spectroscopy and micro-X-ray diffraction, complemented by laboratory analyses. GB COPR contained 30percent of its total Cr(VI) (6000 mg/kg) as large crystals(>20 ?m diameter) of a previously unreported Na-rich analog of calcium aluminum chromate hydrates. These Cr(VI)-rich phases are thought to be vulnerable to reductive and pH treatments. More than 50percent of themore » Cr(VI) was located within nodules, not easily accessible to dissolved reductants, and bound to Fe-rich hydrogarnet, hydrotalcite, and possibly brucite. These phases are stable over a large pH range, thus harder to dissolve. Brownmilleritewasalso likely associated with physical entrapment of Cr(VI) in the interior of nodules. HB COPR contained no Cr(VI)-rich phases; all Cr(VI) was diffuse within the nodules and absent from the cementing matrix, with hydrogarnet and hydrotalcite being the main Cr(VI) binding phases. Treatment ofHBCOPRis challenging in terms of dissolving the acidity-resistant, inaccessible Cr(VI) compounds; the same applies to ~;;50percent of Cr(VI) in GB COPR.« less

Vapour phase growth and characterization of II-VI mixed crystals

NASA Astrophysics Data System (ADS)

Reddy, D. R.; Reddy, B. K.

1992-02-01

All II-VI semiconductors with melting temperatures well above 1000 degree(s)C and with appreciable congruent vaporization well below their melting temperatures leave little scope for any growth technique except for the slow but efficient vaporphase growth method. Theoretical flaw in diffusion models of vapor phase growth was corrected by Factor and Garrett by incorporating the flow velocity term which otherwise would lead to segregation of constituents. An additional degree of freedom arising from the presence of two components was well utilized to finely control the stoichiometry in binaries. In mixed II-VI systems the components are either three or four, depending on whether the system is a ternary or a quaternary. The added degrees of freedom make it very difficult to control stoichiometry. However, Igaki et al. demonstrated the feasibility of control of stoichiometry in CdSxSe1-x. In this paper, a self-sealing vaporphase growth technique used for both ternary and quaternary system is described. The systems studied are CdSxSe1-x, (ZnSe)x(CdTe)1-x and (ZnTe)x(CdSe)1-x. Results on growth mechanism, miscibility, structure, band gap variation, conductivity type variation with 'x' and transport properties are presented in a comparative way and discussed. CdSxSe1-x system in the entire 'X' has the same crystal structure and type of conductivity. The second system has the same zincblend structure but the type of conductivity is very sensitive to thermal treatment. In the last system both structure and types of conductivity are different. The discontinuities in properties associated with this divergent end compound are presented and discussed. Among the physical properties/parameters studied crystal structure, bandgap and nature of conductivity are tailorable, and magnitudes of conductivity and dielectric properties are very difficult to control in the crystals grown by this vapor phase method.

Estimation of fluoride concentration in drinking water and common beverages in United Arab Emirates (UAE).

PubMed

Walia, Tarun; Abu Fanas, Salem; Akbar, Madiha; Eddin, Jamal; Adnan, Mohamad

2017-07-01

To assess fluoride concentration in drinking water which include tap water of 4 emirates - Abu Dhabi, Dubai, Sharjah and Ajman plus bottled water, commonly available soft drinks & juices in United Arab Emirates. Five different samples of tap water collected from each of the four emirates of UAE: Ajman, Sharjah, Abu Dhabi and Dubai; twenty-two brands of bottled water and fifteen brands of popular cold beverages, purchased from different supermarkets in U.A.E were tested using ion selective electrode method and the fluoride concentration was determined. The mean fluoride content of tap water samples was 0.14 mg F/L with a range of 0.04-0.3 mg F/L; with Ajman tap water samples showing the highest mean fluoride content of 0.3 mg F/L. The mean fluoride content for both bottled drinking water and beverages was 0.07 mg F/L with a range of 0.02-0.50 mg F/L and 0.04-0.1 mg F/L respectively. Majority (68.2%) of the bottled water are produced locally within U.A.E while a few (31.8%) are imported. The tap water, bottled water and beverages available in U.A.E show varying concentrations of fluoride, however none showed the optimal level necessary to prevent dental caries. Dental professionals in U.A.E should be aware of the fluoride concentrations before prescribing fluoride supplements to children.

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

PubMed

Pfützner, Andreas; Pesach, Gidi; Nagar, Ron

2017-06-01

Injectable life-saving drugs should not be exposed to temperatures <4°C/39°F or >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 < 29°C/84.2°F for a minimum of 12 h without external power requirement, even when constantly exposed to an outside temperature of 37.8°C/100°F. Bringing the device into an ambient temperature < 26°C/78.8°F reverses the 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.

IV-VI semiconductor lasers for gas phase biomarker detection

NASA Astrophysics Data System (ADS)

McCann, Patrick; Namjou, Khosrow; Roller, Chad; McMillen, Gina; Kamat, Pratyuma

2007-09-01

A promising absorption spectroscopy application for mid-IR lasers is exhaled breath analysis where sensitive, selective, and speedy measurement of small gas phase biomarker molecules can be used to diagnose disease and monitor therapies. Many molecules such as nitric oxide, ethane, formaldehyde, acetaldehyde, acetone, carbonyl sulfide, and carbon disulfide have been connected to diseases or conditions such as asthma, oxidative stress, breast cancer, lung cancer, diabetes, organ transplant rejection, and schizophrenia. Measuring these and other, yet to be discovered, biomarker molecules in exhaled breath with mid-IR lasers offers great potential for improving health care since such tests are non-invasive, real-time, and do not require expensive consumables or chemical reagents. Motivated by these potential benefits, mid-IR laser spectrometers equipped with presently available cryogenically-cooled IV-VI lasers mounted in compact Stirling coolers have been developed for clinical research applications. This paper will begin with a description of the development of mid-IR laser instruments and their use in the largest known exhaled breath clinical study ever performed. It will then shift to a description of recent work on the development of new IV-VI semiconductor quantum well materials and laser fabrication methods that offer the promise of low power consumption (i.e. efficient) continuous wave emission at room temperature. Taken together, the demonstration of compelling clinical applications with large market opportunities and the clear identification of a viable pathway to develop low cost mid-IR laser instrumentation can create a renewed focus for future research and development efforts within the mid-IR materials and devices area.

Human rights and health disparities for migrant workers in the UAE.

PubMed

Sönmez, Sevil; Apostolopoulos, Yorghos; Tran, Diane; Rentrope, Shantyana

2011-12-15

Systematic violations of migrant workers' human rights and striking health disparities among these populations in the United Arab Emirates (UAE) are the norm in member countries of the Gulf Cooperation Council (GCC). Migrant laborers comprise about 90 percent of the UAE workforce and include approximately 500,000 construction workers and 450,000 domestic workers. Like many other GCC members countries, the UAE witnessed an unprecedented construction boom during the early 2000s, attracting large numbers of Western expatriates and increasing demand for cheap migrant labor. Elite Emiratis' and Western expatriates' dependence on household staff further promoted labor migration. This paper offers a summary of existing literature on migrant workers and human rights in the UAE, focusing on their impact on related health ramifications and disparities, with specific attention to construction workers, domestic workers, and trafficked women and children. Construction workers and domestic laborers are victims of debt bondage and face severe wage exploitation, and experience serious health and safety problems resulting from inhumane work and living conditions. High rates of physical, sexual, and psychological abuse impact the health of domestic workers. Through a review of available literature, including official reports, scientific papers, and media reports, the paper discusses the responsibility of employers, governments, and the global community in mitigating these problems and reveals the paucity of systematic data on the health of migrant workers in the Gulf. Copyright © 2011 Sonmez, Apostolopoulos, Tran, and Rentrope. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited.

Use of a Ferrous Sulfate - Sodium Dithionite Blend to Treat a Dissolved Phase Cr(VI) Plume

EPA Science Inventory

A field study was conducted to evaluate the use of a combination of sodium dithionite and ferrous sulfate in creating an in situ redox zone for treatment of a dissolved phase Cr(VI) plume at a former industrial site. The reductant blend was injected into the path of a dissolved ...

Resistance, bioaccumulation and solid phase extraction of uranium (VI) by Bacillus vallismortis and its UV-vis spectrophotometric determination.

PubMed

Ozdemir, Sadin; Oduncu, M Kadir; Kilinc, Ersin; Soylak, Mustafa

2017-05-01

Bioaccumulation, resistance and preconcentration of uranium(VI) by thermotolerant Bacillus vallismortis were investigated in details. The minimum inhibition concentration of (MIC) value of U(VI) was found as 85 mg/L and 15 mg/L in liquid and solid medium, respectively. Furthermore, the effect of various U(VI) concentrations on the growth of bacteria and bioaccumulation on B. vallismortis was examined in the liquid culture media. The growth was not significantly affected in the presence of 1.0, 2.5 and 5.0 mg/L U(VI) up to 72 h. The highest bioaccumulation value at 1 mg/L U(VI) concentration was detected at the 72nd hour (10 mg/g metal/dry bacteria), while the maximum bioaccumulation value at 5 mg/L U(VI) concentration was determined at the 48th hour (50 mg metal/dry bacteria). In addition to these, various concentration of U(VI) on α-amylase production was studied. The α-amylase activities at 0, 1, 2.5 and 5 mg/L U(VI) were found as 3313.2, 3845.2, 3687.1 and 3060.8 U/mg, respectively at 48th. Besides, uranium (VI) ions were preconcentrated with immobilized B. vallismortis onto multiwalled carbon nanotube (MWCNT) and were determined by UV-vis spectrophotometry. The surface macro structure and functionalities of B. vallismortis immobilized onto multiwalled carbon nanotube with and without U(VI) were examined by FT-IR and SEM. The optimum pH and flow rate for the biosorption of U(VI) were 4.0-5.0 and 1.0 mL/min, respectively. The quantitative elution occurred with 5.0 mL of 1 mol/L HCl. The loading capacity of immobilized B. vallismortis was determined as 23.6 mg/g. The certified reference sample was employed for the validation of developed solid phase extraction method. The new validated method was applied to the determination of U(VI) in water samples from Van Lake-Turkey. Copyright © 2017 Elsevier Ltd. All rights reserved.

Recovery Of Chromium Metal (VI) Using Supported Liquid Membrane (SLM) Method, A study of Influence of NaCl and pH in Receiving Phase on Transport

NASA Astrophysics Data System (ADS)

Cholid Djunaidi, Muhammad; Lusiana, Retno A.; Rahayu, Maya D.

2017-06-01

Chromium metal(VI) is a valuable metal but in contrary has high toxicity, so the separation and recovery from waste are very important. One method that can be used for the separation and recovery of chromium (VI) is a Supported Liquid Membrane (SLM). SLM system contains of three main components: a supporting membrane, organic solvents and carrier compounds. The supported Membrane used in this research is Polytetrafluoroethylene (PTFE), organic solvent is kerosene, and the carrier compound used is aliquat 336. The supported liquid membrane is placed between two phases, namely, feed phase as the source of analyte (Cr(VI)) and the receiving phase as the result of separation. Feed phase is the electroplating waste which contains of chromium metal with pH variation about 4, 6 and 9. Whereas the receiving phase are the solution of HCl, NaOH, HCl-NaCl and NaOH-NaCl with pH variation about 1, 3, 5 and 7. The efficiency separation is determined by measurement of chromium in the feed and the receiving phase using AAS (Atomic Absorption Spectrophotometry). The experiment results show that transport of Chrom (VI) by Supported Liquid membrane (SLM) is influenced by pH solution in feed phase and receiving phase as well as NaCl in receiving phase. The highest chromium metal is transported from feed phase about 97,78%, whereas in receiving phase shows about 58,09%. The highest chromium metal transport happens on pH 6 in feed phase, pH 7 in receiving phase with the mixture of NaOH and NaCl using carrier compound aliquat 336.

Localising Content for an XMOOC in the UAE

ERIC Educational Resources Information Center

Eppard, Jenny; Reddy, Preeya

2017-01-01

Universities in the UAE are entering the age of virtual and open access education. This paper describes the evolution of a MOOC at a state-funded university in Dubai. We will describe the challenges as well as a reflection of our experiences as creating virtual learning spaces in this culture differs somewhat from Western models. [For the complete…

Ranking of priorities in employees' reward and recognition schemes: from the perspective of UAE health care employees.

PubMed

Younies, Hassan; Barhem, Belal; Younis, Mustafa Z

2008-01-01

A reward and recognition (RR) system is a tool widely applied by organizations to motivate their employees. Outstanding employees expect their effort to be acknowledged by the organization. However, the variety of rewards and recognitions systems used by organizations may be perceived differently by different employees. The diverse workforce structure in the United Arab Emirates (UAE) poses various challenges for organization managers. Managers need to implement the shrewd RR system which best fits their diverse workforce. This research studied how medical sector employees in the private and public health sector view the RR systems in the UAE. Two lists, comprising 26 major approaches to RR, were prepared and its items prioritized by taking inputs from 250 employees working in more than 30 varied public and private health care organizations in the UAE. The findings of the research are expected to provide guidelines for developing appropriate RR systems for organizations in general, and UAE health care organizations in particular.

Bis(tetra­methyl­ammonium) tetra­chlorido­zincate(II), phase VI

PubMed Central

Curtiss, Ashley B. S.; Musie, Ghezai T.; Powell, Douglas R.

2008-01-01

Phase VI of bis­(tetra­methyl­ammonium) tetra­chloro­zincate(II), (C4H12N)2[ZnCl4], contains three formula units per asymmetric unit. Several short C—H⋯Cl contacts [2.70 (3) and 2.72 (4) Å] are observed, but they are believed to participate only in van der Waals inter­actions. The crystal studied exhibited inversion twinning. PMID:21200531

Building a Sustainable Higher Education Sector in the UAE

ERIC Educational Resources Information Center

Jose, Saju; Chacko, Jacob

2017-01-01

Purpose: The purpose of this paper is to examine the relevant economic aspects that could affect the sustainability of the HE sector in the UAE. Design/methodology/approach: Data are collected mainly through secondary sources and based on the relevant information. Two constructs, namely, market factors and educational governance are identified…

Electro-enhanced hollow fiber membrane liquid phase microextraction of Cr(VI) oxoanions in drinking water samples.

PubMed

Chanthasakda, Nattaporn; Nitiyanontakit, Sira; Varanusupakul, Pakorn

2016-02-01

Hollow fiber membrane liquid phase microextraction (HF-LPME) of metal oxoanions was studied using an ionic carrier enhanced by the application of an electric field (electro-enhanced HF-LPME). The Cr(VI) oxoanion was used as the model. The transportation of Cr(VI) oxoanions across the supported liquid membrane (SLM) was explored via the ion-exchange process and electrokinetic migration. The type of SLM, type of acceptor solution, extraction time, electric potential, and stirring rate were investigated and optimized using MilliQ water. Electro-enhanced HF-LPME provided a much higher enrichment factor compared to conventional HF-LPME (no electric potential) for the same extraction time. A mixture of an anion exchange carrier (methyltrialkyl-ammonium chloride, Aliquat 336) in the SLM facilitated the transportation of Cr(VI) oxoanions. The SLM that gave the best performance was 1-heptanol mixed with 5% Aliquat 336 with 1M NaOH as the acceptor. Linearity was obtained in the working range of 3-15 µg L(-1) Cr(VI) (R(2)>0.99) at 30 V with a 5 min extraction time. The limit of detection was below 5 µg L(-1). The relative standard deviation was less than 12%. The method was applied to drinking water samples. The recoveries of spiked Cr(VI) in drinking water samples were in the range of 96-101% based on the matrix-matched calibration curves. The method was limited to samples containing low levels of ions due to the occurrence of electrolysis. The type of SLM, particularly regarding its resistance, should be tuned to control this problematic phenomenon. Copyright © 2015 Elsevier B.V. All rights reserved.

The Path to Development: Expatriate Faculty Retention in the UAE

ERIC Educational Resources Information Center

Schoepp, Kevin W.

2011-01-01

Given the rapid development and large expatriate majority within the United Arab Emirates, the country is extremely reliant upon expatriate faculty to educate its people. Through the lens provided by Social Exchange Theory, this study examined the motivations of expatriate faculty to remain or leave their positions at institutions within the UAE.…

US-UAE Relations: A Partnership Threatened by Differences Regarding Human Rights

DTIC Science & Technology

2010-03-01

Furthermore, UAE‟s approach to opening its markets to foreign companies continues to attract US investors and businesses alike. Over 750 US...companies to include Microsoft, Exxon Mobil, Lockeed Martin, United Airlines, and Starbucks currently maintain a presence in the UAE. 19 An additional

Understanding Student Satisfaction and Loyalty in the UAE HE Sector

ERIC Educational Resources Information Center

Fernandes, Cedwyn; Ross, Kieran; Meraj, Mohammad

2013-01-01

Purpose: The purpose of this paper is to verify and estimate the impact of the antecedents of Programme satisfaction and to explore its link with student loyalty in the higher education (HE) sector in the United Arab Emirates (UAE). Design/methodology/approach: A Programme Experience Questionnaire (PEQ) was developed, based on the National Student…

The United Arab Emirates (UAE): Issues for U.S. Policy

DTIC Science & Technology

2013-10-17

foot section of the Zayid Port for use by the French navy ; (2) an installation at Dhafra Air Base to be used by France’s air force; and (3) a barracks...York Times report that the UAE had hired the firm, which is run by Eric Prince, who founded the Blackwater security contractor, to a $529 million

Specialty preferences and motivating factors: A national survey on medical students from five uae medical schools.

PubMed

Abdulrahman, Mahera; Makki, Maryam; Shaaban, Sami; Al Shamsi, Maryam; Venkatramana, Manda; Sulaiman, Nabil; Sami, Manal M; Abdelmannan, Dima K; Salih, AbdulJabbar M A; AlShaer, Laila

2016-01-01

Workforce planning is critical for being able to deliver appropriate health service and thus is relevant to medical education. It is, therefore, important to understand medical students' future specialty choices and the factors that influence them. This study was conducted to identify, explore, and analyze the factors influencing specialty preferences among medical students of the United Arab Emirates (UAE). A multiyear, multicenter survey of medical student career choice was conducted with all five UAE medical schools. The questionnaire consisted of five sections. Chi-squared tests, regression analysis, and stepwise logistic regression were performed. The overall response rate was 46% (956/2079). Factors that students reported to be extremely important when considering their future career preferences were intellectual satisfaction (87%), work-life balance (71%), having the required talent (70%), and having a stable and secure future (69%). The majority of students (60%) preferred internal medicine, surgery, emergency medicine, or family Medicine. The most common reason given for choosing a particular specialty was personal interest (21%), followed by flexibility of working hours (17%). The data show that a variety of factors inspires medical students in the UAE in their choice of a future medical specialty. These factors can be used by health policymakers, university mentors, and directors of residency training programs to motivate students to choose specialties that are scarce in the UAE and therefore better serve the health-care system and the national community.

Tolerance and bioaccumulation of U(VI) by Bacillus mojavensis and its solid phase preconcentration by Bacillus mojavensis immobilized multiwalled carbon nanotube.

PubMed

Özdemir, Sadin; Oduncu, M Kadir; Kilinc, Ersin; Soylak, Mustafa

2017-02-01

In this study, uranium(VI) tolerance and bioaccumulation were investigated by using thermo -tolerant Bacillus mojavensis. The level of U(VI) was measured by UV-VIS spectrophotometry. The minimum inhibition concentration (MIC) value of U(VI) was experimented. Bacterial growth was not affected in the presence of 1.0 and 2.5 mg/L U(VI) at 36 h and the growth was partially affected in the presence of 5 mg/L U(VI) at 24 h. What was obtained from this study is that there was diversity in the various periods of the growth phases of metal bioaccumulation capacity, which was shown by B. mojavensis. The maximum bioaccumulation capacities were found to be 12.8, 22.7, and 48.2 mg/g dried bacteria, at 24th hours at concentration of 1.0, 2.5 and 5 mg/L U(VI), respectively. In addition to these, U(VI) has been preconcentrated on B. mojavensis immobilized MWCNT. Several factors such as pH, flow rate of solution, amount of biosorbent and support materials, eluent type, concentration and volume, the matrix interference effect on retention have been studied, and extraction conditions were optimized. Preconcentration factor was achieved as 60. Under the optimized conditions, the limit of detection (LOD) and quantification (LOQ) were calculated as 0.74 and 2.47 μg/L. The biosorption capacity of immobilized B. mojavensis was calculated for U(VI) as 25.8 mg/g. The results demonstrated that the immobilized biosorbent column could be reused at least 30 cycles of biosorption and desorption with the higher than 95% recovery. FT-IR and SEM analysis were performed to understand the surface properties of B. mojavensis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Incidence and prevalence of systemic lupus erythematosus among the native Arab population in UAE.

PubMed

Al Dhanhani, A M; Agarwal, M; Othman, Y S; Bakoush, O

2017-05-01

Background and objectives There is a paucity of information about the epidemiology of systemic lupus erythematosus (SLE) amongst Arabs. The objective of this study was to determine the incidence and prevalence of SLE among the native Arab population of United Arab Emirates (UAE). Methods Patients with SLE were identified from three sources: medical records of two local tertiary hospitals (four years; 2009 to 2012), laboratory requests for serum double stranded deoxyribonucleic acid and serum anti-nuclear antibody and confirmed histopathologic diagnosis of SLE (skin and kidney biopsy specimens). All the patients identified with SLE met the criteria of the American College of Rheumatology. Incidence and prevalence were calculated using the state records of the UAE native population as the denominator. The age-adjusted incidence was calculated by direct standardization using the World Health Organization world standard population 2000-2025. Results Sixteen new cases (13 females and three males) fulfilled the American College of Rheumatology SLE criteria. The mean (±SD) age at time of diagnosis was 28.6 ± 12.4 years. The crude incidence ratio (per 100,000 population) was 3.5, 1.1, 2.1 and 2.1 in years 2009, 2010, 2011, 2012, respectively. The age-standardized incidence per 100,000 population for the four years was 8.6 (95% confidence interval 4.2-15.9). The age-standardized prevalence of SLE among the native population according to the 2012 population consensus was 103/100,000 population (95% confidence interval 84.5-124.4). Conclusion The age-adjusted incidence and prevalence among UAE Arabs is higher than has been reported among most other Caucasian populations. Furthermore, the prevalence of SLE in UAE seems much higher than other similar Arab countries in the Gulf region.

Reporting child abuse cases by dentists working in the United Arab Emirates (UAE).

PubMed

Al-Amad, Suhail H; Awad, Manal A; Al-Farsi, Laila H; Elkhaled, Rawan H

2016-05-01

Reporting of suspicious cases of child abuse is a sensitive issue that is often hindered by uncertainty of diagnosis. This cross sectional study aimed to assess the UAE dentists' experiences in child abuse recognition, the factors that prevent them from reporting suspicious cases to authorities and their perceived training needs. A closed-ended, self-administered questionnaire was distributed to 350 dentists working in the UAE. Chi Square test was used to determine association between training needs on child abuse and its reporting rate. Logistic regression was used to determine the association between perceived training needs and other covariates. One hundred and ninety three respondents satisfied the inclusion criteria. Forty seven (25%) dentists reported encountering a suspicious child abuse case at least once in their career, but only 15 (32%) of those reported their suspicion. Fear of making the wrong diagnosis was the most frequent challenge hindering reporting and dentists who demonstrated a need for specialized training were more likely to express this fear (OR = 5.88, 95% CI: 0.07, 0.45; P = 0.00). The majority of UAE dentists do not report their suspicion to authorities and specialized training should be offered to build dentists' capacity in diagnosing and appropriately reporting suspicious child abuse cases. Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Public Perception on Disaster Management Using Volunteered Geographic Information (vgi): Case of Uae

NASA Astrophysics Data System (ADS)

Yagoub, M. M.

2015-10-01

The number of smart phones that are supported by location facility like Global Positioning System (GPS), Camera and connected to the internet has increased sharply in UAE during the last five years. This increase offers a chance to capitalize on using these devices as resources for data collection, therefore reducing cost. In many cases specific events may happen in areas or at time where there may be no governmental departments to collect such unrepeated events. The current research will showcase various studies that had been conducted on Volunteered Geographic Information (VGI) debating various aspects such as accuracy, legal issues, and privacy. This research will also integrate Geographic Information System (GIS), VGI, social media tools, data mining, and mobile technology to design a conceptual framework for promoting public participation in UAE. The data gathered through survey will be helpful in correlating various aspects of VGI. Since there are diverse views about these aspects, policy makers are left undecided in many countries about how to deal with VGI. The assessment of the UAE case will contribute to the age-long debate by examining the willingness of the public to participate. The result will show the public perception to be as sensors for data collection. Additionally, the potential of citizen involvement in the risk and disaster management process by providing voluntary data collected for VGI applications will also be explored in the paper.

Prevalence of overweight and obesity in United Arab Emirates Expatriates: the UAE National Diabetes and Lifestyle Study.

PubMed

Sulaiman, Nabil; Elbadawi, Salah; Hussein, Amal; Abusnana, Salah; Madani, Abdulrazzag; Mairghani, Maisoon; Alawadi, Fatheya; Sulaiman, Ahmad; Zimmet, Paul; Huse, Oliver; Shaw, Jonathan; Peeters, Anna

2017-01-01

To describe current prevalence of obesity and related non-communicable diseases (NCDs) in expatriates living in the United Arab Emirates (UAE). We used data from the cross-sectional UAE National Diabetes and Lifestyle Study (UAEDIAB), which surveyed adult expatriates living in the UAE for at least 4 years. We report crude prevalence of overweight and obesity, indicated by gender and ethnicity-specific body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) cut-offs, by lifestyle and biomedical characteristics, as well as age and sex-adjusted odds ratios. Out of a total of 3064 recruited expatriates (response rate 68%), 2724 had completed all stages of the UAEDIAB study. Expatriates were; 81% men, mean age 38 years (range 18-80), 71% South East Asians, and 36% university graduates. In this sample, the prevalence of overweight and obesity, by BMI, were 43.0 and 32.3%, respectively. 52.4 and 56.5% of participants were at a substantially increased risk according to WC and WHR, respectively. The prevalence of diabetes, hypertension and hypercholesterolemia were 15.5, 31.8, and 51.7%, respectively, with the prevalence of each being higher in those with obesity. Prevalence of obesity and associated NCDs are extremely high in UAE expatriates. Without comprehensive prevention and management, levels of disease will continue to increase and productivity will fall.

Ultrasound-assisted extraction (UAE) and solvent extraction of papaya seed oil: yield, fatty acid composition and triacylglycerol profile.

PubMed

Samaram, Shadi; Mirhosseini, Hamed; Tan, Chin Ping; Ghazali, Hasanah Mohd

2013-10-10

The main objective of the current work was to evaluate the suitability of ultrasound-assisted extraction (UAE) for the recovery of oil from papaya seed as compared to conventional extraction techniques (i.e., Soxhlet extraction (SXE) and solvent extraction (SE)). In the present study, the recovery yield, fatty acid composition and triacylglycerol profile of papaya seed oil obtained from different extraction methods and conditions were compared. Results indicated that both solvent extraction (SE, 12 h/25 °C) and ultrasound-assisted extraction (UAE) methods recovered relatively high yields (79.1% and 76.1% of total oil content, respectively). Analysis of fatty acid composition revealed that the predominant fatty acids in papaya seed oil were oleic (18:1, 70.5%-74.7%), palmitic (16:0, 14.9%-17.9%), stearic (18:0, 4.50%-5.25%), and linoleic acid (18:2, 3.63%-4.6%). Moreover, the most abundant triacylglycerols of papaya seed oil were triolein (OOO), palmitoyl diolein (POO) and stearoyl oleoyl linolein (SOL). In this study, ultrasound-assisted extraction (UAE) significantly (p < 0.05) influenced the triacylglycerol profile of papaya seed oil, but no significant differences were observed in the fatty acid composition of papaya seed oil extracted by different extraction methods (SXE, SE and UAE) and conditions.

Feeding the fire: tracing the mass-loading of 107 K galactic outflows with O VI absorption

NASA Astrophysics Data System (ADS)

Chisholm, J.; Bordoloi, R.; Rigby, J. R.; Bayliss, M.

2018-02-01

Galactic outflows regulate the amount of gas galaxies convert into stars. However, it is difficult to measure the mass outflows remove because they span a large range of temperatures and phases. Here, we study the rest-frame ultraviolet spectrum of a lensed galaxy at z ˜ 2.9 with prominent interstellar absorption lines from O I, tracing neutral gas, up to O VI, tracing transitional phase gas. The O VI profile mimics weak low-ionization profiles at low velocities, and strong saturated profiles at high velocities. These trends indicate that O VI gas is co-spatial with the low-ionization gas. Further, at velocities blueward of -200 km s-1 the column density of the low-ionization outflow rapidly drops while the O VI column density rises, suggesting that O VI is created as the low-ionization gas is destroyed. Photoionization models do not reproduce the observed O VI, but adequately match the low-ionization gas, indicating that the phases have different formation mechanisms. Photoionized outflows are more massive than O VI outflows for most of the observed velocities, although the O VI mass outflow rate exceeds the photoionized outflow at velocities above the galaxy's escape velocity. Therefore, most gas capable of escaping the galaxy is in a hot outflow phase. We suggest that the O VI absorption is a temporary by-product of conduction transferring mass from the photoionized phase to an unobserved hot wind, and discuss how this mass-loading impacts the observed circum-galactic medium.

Effect of phosphate on U(VI) sorption to montmorillonite: Ternary complexation and precipitation barriers

NASA Astrophysics Data System (ADS)

Troyer, Lyndsay D.; Maillot, Fabien; Wang, Zheming; Wang, Zimeng; Mehta, Vrajesh S.; Giammar, Daniel E.; Catalano, Jeffrey G.

2016-02-01

Phosphate addition is a potential treatment method to lower the solubility of U(VI) in soil and groundwater systems by causing U(VI) phosphate precipitation as well as enhancing adsorption. Previous work has shown that iron oxide surfaces may facilitate the nucleation of U(VI) phosphate minerals and, that under weakly acidic conditions, phosphate also enhances U(VI) adsorption to such phases. Like iron oxides, clays are important reactive phases in the subsurface but little is known about the interaction of U(VI) and phosphate with these minerals. The effect of aqueous phosphate on U(VI) binding to Wyoming montmorillonite (SWy-2) in air-equilibrated systems was investigated. Equilibrium U(VI) uptake to montmorillonite was determined at pH 4, 6 and 8 at discrete initial phosphate concentrations between 0 and 100 μM. The observed behavior of U(VI) indicates a transition from adsorption to precipitation with increasing total uranium and phosphate concentrations at all pH values. At the highest phosphate concentration examined at each pH value, a barrier to U(VI) phosphate nucleation is observed. At lower concentrations, phosphate has no effect on macroscopic U(VI) adsorption. To assess the mechanisms of U(VI)-phosphate interactions on smectite surfaces, U(VI) speciation was investigated under selected conditions using laser-induced fluorescence spectroscopy (LIFS) and extended X-ray absorption fine-structure (EXAFS) spectroscopy. Samples above the precipitation threshold display EXAFS and LIFS spectral signatures consistent with the autunite family of U(VI) phosphate minerals. However, at lower U(VI) concentrations, changes in LIFS spectra upon phosphate addition suggest that U(VI)-phosphate ternary surface complexes form on the montmorillonite surface at pH 4 and 6 despite the lack of a macroscopic effect on adsorption. The speciation of solid-associated U(VI) below the precipitation threshold at pH 8 is dominated by U(VI)-carbonate surface complexes. This work

Effect of Phosphate on U(VI) Sorption to Montmorillonite: Ternary Complexation and Precipitation Barriers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Troyer, Lyndsay D.; Maillot, Fabien; Wang, Zheming

Phosphate addition is a potential treatment method to lower the solubility of U(VI) in soil and groundwater systems by causing U(VI) phosphate precipitation as well as enhancing adsorption. Previous work has shown that iron oxide surfaces may facilitate the nucleation of U(VI) phosphate minerals and, that under weakly acidic conditions, phosphate also enhances U(VI) adsorption to such phases. Like iron oxides, clays are important reactive phases in the subsurface but little is known about the interaction of U(VI) and phosphate with these minerals. The effect of aqueous phosphate on U(VI) binding to Wyoming montmorillonite (SWy-2) in air-equilibrated systems was investigated.more » Equilibrium U(VI) uptake to montmorillonite was determined at pH 4, 6 and 8 at discrete initial phosphate concentrations between 0 and 100 μM. The observed behavior of U(VI) indicates a transition from adsorption to precipitation with increasing total uranium and phosphate concentrations at all pH values. At the highest phosphate concentration examined at each pH value, a barrier to U(VI) phosphate nucleation is observed. At lower concentrations, phosphate has no effect on macroscopic U(VI) adsorption. To assess the mechanisms of U(VI)-phosphate interactions on smectite surfaces, U(VI) speciation was investigated under selected conditions using laser-induced fluorescence spectroscopy (LIFS) and extended X-ray absorption fine-structure (EXAFS) spectroscopy. Samples above the precipitation threshold display EXAFS and LIFS spectral signatures consistent with the autunite family of U(VI) phosphate minerals. However, at lower U(VI) concentrations, changes in LIFS spectra upon phosphate addition suggest that U(VI)-phosphate ternary surface complexes form on the montmorillonite surface at pH 4 and 6 despite the lack of a macroscopic effect on adsorption. The speciation of solid-associated U(VI) below the precipitation threshold at pH 8 is dominated by U(VI)-carbonate surface complexes. This

Replication profile of Saccharomyces cerevisiae chromosome VI.

PubMed

Friedman, K L; Brewer, B J; Fangman, W L

1997-11-01

An understanding of the replication programme at the genome level will require the identification and characterization of origins of replication through large, contiguous regions of DNA. As a step toward this goal, origin efficiencies and replication times were determined for 10 ARSs spanning most of the 270 kilobase (kb) chromosome VI of Saccharomyces cerevisiae. Chromosome VI shows a wide variation in the percentage of cell cycles in which different replication origins are utilized. Most of the origins are activated in only a fraction of cells, suggesting that the pattern of origin usage on chromosome VI varies greatly within the cell population. The replication times of fragments containing chromosome VI origins show a temporal pattern that has been recognized on other chromosomes--the telomeres replicate late in S phase, while the central region of the chromosome replicates early. As demonstrated here for chromosome VI, analysis of the direction of replication fork movement along a chromosome and determination of replication time by measuring a period of hemimethylation may provide an efficient means of surveying origin activity over large regions of the genome.

An Empirical Investigation of Smart Board Innovations in Teaching in UAE University

ERIC Educational Resources Information Center

Al-Qirim, Nabeel

2016-01-01

This research investigates Teaching Faculty's (TF) adoption and usage of the Interactive or Smart White Board Technology (SB) in UAE University (UAEU). The developed theoretical framework is based on the technological innovation theories and is made of different socio-technical factors. Using survey research targeting UAEU's TF, the research…

Effect of uranium(VI) speciation on simultaneous microbial reduction of uranium(VI) and iron(III).

PubMed

Stewart, Brandy D; Amos, Richard T; Fendorf, Scott

2011-01-01

Uranium is a pollutant of concern to both human and ecosystem health. Uranium's redox state often dictates whether it will reside in the aqueous or solid phase and thus plays an integral role in the mobility of uranium within the environment. In anaerobic environments, the more oxidized and mobile form of uranium (UO2(2+) and associated species) may be reduced, directly or indirectly, by microorganisms to U(IV) with subsequent precipitation of UO. However, various factors within soils and sediments, such as U(VI) speciation and the presence of competitive electron acceptors, may limit biological reduction of U(VI). Here we examine simultaneous dissimilatory reduction of Fe(III) and U(VI) in batch systems containing dissolved uranyl acetate and ferrihydrite-coated sand. Varying amounts of calcium were added to induce changes in aqueous U(VI) speciation. The amount of uranium removed from solution during 100 h of incubation with S. putrefaciens was 77% in absence of Ca or ferrihydrite, but only 24% (with ferrihydrite) and 14% (without ferrihydrite) were removed for systems with 0.8 mM Ca. Dissimilatory reduction of Fe(III) and U(VI) proceed through different enzyme pathways within one type of organism. We quantified the rate coefficients for simultaneous dissimilatory reduction of Fe(III) and U(VI) in systems varying in Ca concecentration (0-0.8 mM). The mathematical construct, implemented with the reactive transport code MIN3P, reveals predominant factors controlling rates and extent of uranium reduction in complex geochemical systems.

A survey with Copernicus of interstellar O VI absorption

NASA Technical Reports Server (NTRS)

Jenkins, E. B.; Meloy, D. A.

1974-01-01

The presence of broad, shallow absorptions caused by O VI ions were revealed from UV spectra observations recorded by the Copernicus satellite for thirty-two stars. A table lists survey data on the stars observed for which values of the O VI column densities or their upper limits are extracted. Interstellar rather than circumstellar origin is evident from observation of the lack of correspondence between radical velocities of the stars and those of the O VI profiles. The presence of a low-density high-temperature phase of interstellar gas produced by supernova explosions is suggested.

Exploratory study into awareness of heart disease and health care seeking behavior among Emirati women (UAE) - Cross sectional descriptive study.

PubMed

Khan, Sarah; Ali, Syed Adnan

2017-09-26

Cardiovascular disease was the leading cause of death among women in the United Arab Emirates (UAE) in 2010. Heart attacks usually happen in older women thus symptoms of heart disease may be masked by symptoms of chronic diseases, which could explain the delay in seeking health care and higher mortality following an ischaemic episode among women. This study seeks to a) highlight the awareness of heart diseases among Emirati women and b) to understand Emirati women's health care seeking behaviour in UAE. A cross sectional, descriptive study was conducted using a survey instrument adapted from the American Heart Association National survey. A convenience sample of 676 Emirati women between the ages of 18-55 years completed the questionnaire. The study showed low levels of awareness of heart disease and associated risk factors in Emirati women; only 19.4% participants were found to be aware of heart diseases. Awareness levels were highest in Dubai (OR 2.18, p < 0.05) among all the other emirates and in the 18-45 years age group (OR 2.74, p < 0.05). Despite low awareness levels, women paradoxically perceived themselves to be self-efficacious in seeking health care. Interestingly, just 49.1% Emirati women believed that good quality and affordable health care was available in the UAE. Only 28.8% of the participants believed there were sufficient female doctors to respond to health needs of women in UAE. Furthermore, only 36.7% Emirati women chose to be treated in the UAE over treatment in other countries. Emirati women clearly lack the knowledge on severity and vulnerability to heart disease in the region that is essential to improve cardiovascular related health outcomes. This study has identified the need for wider outreach that focuses on gender and age specific awareness on heart disease risks and symptoms. The study has also highlighted potential modifiable barriers in seeking health care that should be overcome to reduce morbidity and mortality due to heart

IN SITU CR(VI) TREATMENT USING A FERROUS IRON-BASED REDUCTANT

EPA Science Inventory

Laboratory and field studies were conducted to evaluate the performance of a ferrous sulfate/ sodium hydrosulfite (dithionite) reductant blend in treating a hexavalent chromium (Cr(VI)) source area and Cr(VI) dissolved phase plume at a former industrial site in Charleston, South ...

The adsorption behavior of U(VI) on granite.

PubMed

Fan, Q H; Hao, L M; Wang, C L; Zheng, Z; Liu, C L; Wu, W S

2014-03-01

The effects of pH, counter ions and temperature on the adsorption of U(VI) on Beishan granite (BsG) were investigated in the presence and absence of fulvic acid (FA) and humic acid (HA). The adsorption edge of U(VI) on BsG suggested that U(VI) adsorption was mainly controlled by ion exchange and outer-sphere complexation at low pH, whereas inner-sphere complex was the dominant adsorption species in the pH range of 4.0-9.0. Above pH 9.0, Na2U2O7 might play an important role in the rise of U(VI) adsorption again. Counter ions such as Cl(-), SO4(2-) and PO4(3-) can provoke U(VI) adsorption on BsG to some extent, which was directly correlated to the complexing ability of U(VI)-ligand. More noticeably, the large enhancement of U(VI) adsorption in the presence of phosphate can be attributed to the ternary complex formation (BsG-PO4-UO2), precipitation ((UO2)3(PO4)2(s)) and secondary phase (Na-autunite). Both FA and HA can slightly increase U(VI) adsorption at low pH, whereas they strongly inhibited U(VI) adsorption at high pH range. Artificial synthesized granite (AsG) prepared in the laboratory is impossible to use as an analogue of natural granite because of the large difference in the adsorption and surface properties.

Remote sensing of mineral dust aerosol using AERI during the UAE2: A modeling and sensitivity study

NASA Astrophysics Data System (ADS)

Hansell, R. A.; Liou, K. N.; Ou, S. C.; Tsay, S. C.; Ji, Q.; Reid, J. S.

2008-09-01

Numerical simulations and sensitivity studies have been performed to assess the potential for using brightness temperature spectra from a ground-based Atmospheric Emitted Radiance Interferometer (AERI) during the United Arab Emirates Unified Aerosol Experiment (UAE2) for detecting/retrieving mineral dust aerosol. A methodology for separating dust from clouds and retrieving the dust IR optical depths was developed by exploiting differences between their spectral absorptive powers in prescribed thermal IR window subbands. Dust microphysical models were constructed using in situ data from the UAE2 and prior field studies while composition was modeled using refractive index data sets for minerals commonly observed around the UAE region including quartz, kaolinite, and calcium carbonate. The T-matrix, finite difference time domain (FDTD), and Lorenz-Mie light scattering programs were employed to calculate the single scattering properties for three dust shapes: oblate spheroids, hexagonal plates, and spheres. We used the Code for High-resolution Accelerated Radiative Transfer with Scattering (CHARTS) radiative transfer program to investigate sensitivity of the modeled AERI spectra to key dust and atmospheric parameters. Sensitivity studies show that characterization of the thermodynamic boundary layer is crucial for accurate AERI dust detection/retrieval. Furthermore, AERI sensitivity to dust optical depth is manifested in the strong subband slope dependence of the window region. Two daytime UAE2 cases were examined to demonstrate the present detection/retrieval technique, and we show that the results compare reasonably well to collocated AERONET Sun photometer/MPLNET micropulse lidar measurements. Finally, sensitivity of the developed methodology to the AERI's estimated MgCdTe detector nonlinearity was evaluated.

Enhanced abiotic reduction of Cr(VI) in a soil slurry system by natural biomaterial addition.

PubMed

Park, Donghee; Ahn, Chi Kyu; Kim, Young Mi; Yun, Yeoung-Sang; Park, Jong Moon

2008-12-30

Among various plant-based natural biomaterials, pine bark was chosen as an efficient biomaterial capable of removing toxic Cr(VI) from aqueous solution. XPS spectra indicated that Cr(VI) was abiotically reduced to Cr(III) in both liquid and solid phases. The Cr(VI)-reducing capacity of pine bark was determined as 545 (+/-1.3)mg-Cr(VI)g(-1) of it, which was 8.7 times higher than that of a common chemical Cr(VI)-reductant, FeSO4 x 7H2O. Because pine bark could completely reduce toxic Cr(VI) to less toxic or nontoxic Cr(III) even at neutral pH, it was used as an organic reductant to remediate Cr(VI)-contaminated soil in this study. Soil slurry system using a bottle roller was applied to ex situ slurry-phase remediation experiments. In the soil slurry system, pine bark completely reduced Cr(VI) to Cr(III) and adsorbed the reduced-Cr(III) on its surface. Abiotic remediation rate of Cr(VI)-contaminated soil increased with the increase of pine bark dosage and with the decreases of Cr(VI) and water contents. In conclusion, pine bark can be used to remediate Cr(VI)-contaminated soil efficiently and environmentally friendly.

The UAE healthy future study: a pilot for a prospective cohort study of 20,000 United Arab Emirates nationals.

PubMed

Abdulle, Abdishakur; Alnaeemi, Abdullah; Aljunaibi, Abdullah; Al Ali, Abdulrahman; Al Saedi, Khaled; Al Zaabi, Eiman; Oumeziane, Naima; Al Bastaki, Marina; Al-Houqani, Mohammed; Al Maskari, Fatma; Al Dhaheri, Ayesha; Shah, Syed M; Loney, Tom; El-Sadig, Mohamed; Oulhaj, Abderrahim; Wareth, Leila Abdel; Al Mahmeed, Wael; Alsafar, Habiba; Hirsch, Benjamin; Al Anouti, Fatme; Yaaqoub, Jamila; Inman, Claire K; Al Hamiz, Aisha; Al Hosani, Ayesha; Haji, Muna; Alsharid, Teeb; Al Zaabi, Thekra; Al Maisary, Fatima; Galani, Divya; Sprosen, Tim; El Shahawy, Omar; Ahn, Jiyoung; Kirchhoff, Tomas; Ramasamy, Ravichandran; Schmidt, Ann Marie; Hayes, Richard; Sherman, Scott; Ali, Raghib

2018-01-05

The United Arab Emirates (UAE) is faced with a rapidly increasing burden of non-communicable diseases including obesity, diabetes, and cardiovascular disease. The UAE Healthy Future study is a prospective cohort designed to identify associations between risk factors and these diseases amongst Emiratis. The study will enroll 20,000 UAE nationals aged ≥18 years. Environmental and genetic risk factors will be characterized and participants will be followed for future disease events. As this was the first time a prospective cohort study was being planned in the UAE, a pilot study was conducted in 2015 with the primary aim of establishing the feasibility of conducting the study. Other objectives were to evaluate the implementation of the main study protocols, and to build adequate capacity to conduct advanced clinical laboratory analyses. Seven hundred sixty nine UAE nationals aged ≥18 years were invited to participate voluntarily in the pilot study. Participants signed an informed consent, completed a detailed questionnaire, provided random blood, urine, and mouthwash samples and were assessed for a series of clinical measures. All specimens were transported to the New York University Abu Dhabi laboratories where samples were processed and analyzed for routine chemistry and hematology. Plasma, serum, and a small whole blood sample for DNA extraction were aliquoted and stored at -80 °C for future analyses. Overall, 517 Emirati men and women agreed to participate (68% response rate). Of the total participants, 495 (95.0%), 430 (82.2%), and 492 (94.4%), completed the questionnaire, physical measurements, and provided biological samples, respectively. The pilot study demonstrated the feasibility of recruitment and completion of the study protocols for the first large-scale cohort study designed to identify emerging risk factors for the major non-communicable diseases in the region.

Site specific probabilistic seismic hazard analysis at Dubai Creek on the west coast of UAE

NASA Astrophysics Data System (ADS)

Shama, Ayman A.

2011-03-01

A probabilistic seismic hazard analysis (PSHA) was conducted to establish the hazard spectra for a site located at Dubai Creek on the west coast of the United Arab Emirates (UAE). The PSHA considered all the seismogenic sources that affect the site, including plate boundaries such as the Makran subduction zone, the Zagros fold-thrust region and the transition fault system between them; and local crustal faults in UAE. PSHA indicated that local faults dominate the hazard. The peak ground acceleration (PGA) for the 475-year return period spectrum is 0.17 g and 0.33 g for the 2,475-year return period spectrum. The hazard spectra are then employed to establish rock ground motions using the spectral matching technique.

Modeling of the UAE Wind Turbine for Refinement of FAST{_}AD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jonkman, J. M.

The Unsteady Aerodynamics Experiment (UAE) research wind turbine was modeled both aerodynamically and structurally in the FAST{_}AD wind turbine design code, and its response to wind inflows was simulated for a sample of test cases. A study was conducted to determine why wind turbine load magnitude discrepancies-inconsistencies in aerodynamic force coefficients, rotor shaft torque, and out-of-plane bending moments at the blade root across a range of operating conditions-exist between load predictions made by FAST{_}AD and other modeling tools and measured loads taken from the actual UAE wind turbine during the NASA-Ames wind tunnel tests. The acquired experimental test data representmore » the finest, most accurate set of wind turbine aerodynamic and induced flow field data available today. A sample of the FAST{_}AD model input parameters most critical to the aerodynamics computations was also systematically perturbed to determine their effect on load and performance predictions. Attention was focused on the simpler upwind rotor configuration, zero yaw error test cases. Inconsistencies in input file parameters, such as aerodynamic performance characteristics, explain a noteworthy fraction of the load prediction discrepancies of the various modeling tools.« less

Characterization of U(VI) reduction in contaminated sediments with slow-degrading electron donor source

NASA Astrophysics Data System (ADS)

Wu, W.; Watson, D. B.; Zhang, G.; Mehlhorn, T.; Lowe, K.; Earles, J.; Phillips, J.; Kelly, S. D.; Boyanov, M.; Kemner, K. M.; Schadt, C.; Criddle, C. S.; Jardine, P. M.; Brooks, S. C.

2011-12-01

In order to select sustainable, high efficiency and cost effective electron donor source, oleate and emulsified vegetable oil (EVO) were tested uranium (VI) reduction in comparison with ethanol in microcosms using uranium contaminated sediments and groundwater from the US DOE Oak Ridge Integrated Field Research Challenge (ORIFRC) site. The effect of initial sulfate concentration on U(VI) reduction was also tested. Both oleate and EVO were effective electron donor sources for U(VI) reduction. Accumulation of acetate as a major product and the removal of aqueous U(VI) were observed and were associated with sulfate reduction. Both oleate and EVO supported U(VI) reduction but at slower rates with a comparable but slightly lower extent of reduction than ethanol. X-ray absorption near-edge spectroscopy (XANES) analysis confirmed reduction of U(VI) to U(IV). The extent of U(VI) reduction in solid phase was negatively influenced by aqueous calcium concentration. The majority of electrons of the three substrates were consumed by sulfate reduction, Fe(III) reduction, and methanogenesis. Initial U(VI) concentration in the aqueous phase increased with increased sulfate concentration (1 versus 5 mM), likely due to U(VI) desorption from the solid phase. At the higher initial sulfate concentration more U(VI) was reduced and fewer electrons were used in methanogenesis. Analysis of bacterial and archeal populations using 16S rRNA gene libraries showed a significant increase in Deltaproteobacteria after biostimulation. The microbial community structures developed with oleate and EVO were significantly distinct from those developed with ethanol. Bacteria similar to Desulforegula spp. was predominant for oleate and EVO degradation but were not observed in ethanol-amended microcosms. Known U(VI)-reducing bacteria in the microcosms amended with the three electron donor sources included iron(III) reducing Geobacter spp. but in lower abundances than sulfate-reducing Desulfovibrio spp. The

Phase transitions in Group III-V and II-VI semiconductors at high pressure

NASA Technical Reports Server (NTRS)

Yu, S. C.; Liu, C. Y.; Spain, I. L.; Skelton, E. F.

1979-01-01

The structures and transition pressures of Group III-V and II-VI semiconductors and of a pseudobinary system (Ga/x/In/1-x/Sb) have been investigated. Results indicate that GaP, InSb, GaSb, GaAs and possible AlP assume Metallic structures at high pressures; a tetragonal, beta-Sn-like structure is adopted by only InSb and GaSb. The rocksalt phase is preferred in InP, InAs, AlSb, ZnO and ZnS. The model of Van Vechten (1973) gives transition pressures which are in good agreement with measured values, but must be refined to account for the occurrence of the ionic rocksalt structure in some compounds. In addition, discrepancies between the theoretical scaling values for volume changes at the semiconductor-to-metal transitions are observed.

Digital Gender Divides and E-Empowerment in the UAE: A Critical Perspective

ERIC Educational Resources Information Center

Ben Moussa, Mohamed; Seraphim, Joanna

2017-01-01

The phenomenal diffusion and adoption of ICTs in the UAE is widely viewed as a game changer in the country's struggle to address continuous significant gender gaps in the country. The small body of research on this topic has been, however, inconclusive, overtly optimistic, and insufficiently theorized. Addressing these lacuna, the article uses a…

Zig-zag tape influence in NREL Phase VI wind turbine

NASA Astrophysics Data System (ADS)

Gomez-Iradi, Sugoi; Munduate, Xabier

2014-06-01

Two bladed 10 metre diameter wind turbine was tested in the 24.4m × 36.6m NASA-Ames wind tunnel (Phase VI). These experiments have been extensively used for validation purposes for CFD and other engineering tools. The free transition case (S), has been, and is, the most employed one for validation purposes, and consist in a 3° pitch case with a rotational speed of 72rpm upwind configuration with and without yaw misalignment. However, there is another less visited case (M) where identical configuration was tested but with the inclusion of a zig-zag tape. This was called transition fixed sequence. This paper shows the differences between the free and the fix transition cases, that should be more appropriate for comparison with fully turbulent simulations. Steady k-ω SST fully turbulent computations performed with WMB CFD method are compared with the experiments showing, better predictions in the attached flow region when it is compared with the transition fixed experiments. This work wants to prove the utility of M case (transition fixed) and show its differences respect the S case (free transition) for validation purposes.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2007-09-01

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 themore » 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).« less

Study of sorption-retarded U(VI) diffusion in Hanford silt/clay material.

PubMed

Bai, Jing; Liu, Chongxuan; Ball, William P

2009-10-15

A diffusion cell method was applied to measure the effective pore diffusion coefficient (Dp) for U(VI) under strictly controlled chemical conditions in a silt/clay sediment from the U.S. Department of Energy Hanford site, WA. "Inward-flux" diffusion studies were conducted in which [U(VI)] in both aqueous and solid phases was measured as a function of distance in the diffusion cell under conditions of constant concentration at the cell boundaries. A sequential extraction method was developed to measure sorbed contaminant U(VI) in the solid phase containing extractable background U(VI). The effect of sorption kinetics on U(VI) interparticle diffusion was evaluated by comparing sorption-retarded diffusion models with sorption described either as equilibrium or intraparticle diffusion-limited processes. Both experimental and modeling results indicated that (1) a single pore diffusion coefficient can simulate the diffusion of total aqueous U(VI), and (2) the local equilibrium assumption (LEA) is appropriate for modeling sorption-retarded diffusion under the given experimental conditions. Dp of 1.6-1.7 x 10(-6) cm2/s was estimated in aqueous solution at pH 8.0 and saturated with respect to calcite, as relevant to some subsurface regions of the Hanford site.

Nonisovalent Si-III-V and Si-II-VI alloys: Covalent, ionic, and mixed phases

NASA Astrophysics Data System (ADS)

Kang, Joongoo; Park, Ji-Sang; Stradins, Pauls; Wei, Su-Huai

2017-07-01

Nonequilibrium growth of Si-III-V or Si-II-VI alloys is a promising approach to obtaining optically more active Si-based materials. We propose a new class of nonisovalent S i2AlP (or S i2ZnS ) alloys in which the Al-P (or Zn-S) atomic chains are as densely packed as possible in the host Si matrix. As a hybrid of the lattice-matched parent phases, S i2AlP (or S i2ZnS ) provides an ideal material system with tunable local chemical orders around Si atoms within the same composition and structural motif. Here, using first-principles hybrid functional calculations, we discuss how the local chemical orders affect the electronic and optical properties of the nonisovalent alloys.

UAE University Male Students' Interests Impact on Reading and Writing Performance and Improvement

ERIC Educational Resources Information Center

Al Murshidi, Ghadah

2014-01-01

The study examined the impact of the conjunction of structured journal writing and reading for pleasure on students' reading and writing skills. Forty male students from UAE University participated in the study. The participants are of different academic abilities, majors and nationalities. Many of them have little experience with reading for…

Smart Board Technology Success in Tertiary Institutions: The Case of the UAE University

ERIC Educational Resources Information Center

Al-Qirim, Nabeel

2016-01-01

This research explores teaching-faculty's adoption and usage of the Interactive White Board Technology (IWBT) in UAE University (UAEU). The research findings suggested two perspectives concerning IWBT usage by teaching-faculty in UAEU. The first theme is concerned with IWBT's basic features where the IWBT proved its superiority when compared to…

Dynamics of Chromium(VI) Removal from Drinking Water by Iron Electrocoagulation.

PubMed

Pan, Chao; Troyer, Lyndsay D; Catalano, Jeffrey G; Giammar, Daniel E

2016-12-20

The potential for new U.S. regulations for Cr(VI) in drinking water have spurred strong interests in improving technologies for Cr(VI) removal. This study examined iron electrocoagulation for Cr(VI) removal at conditions directly relevant to drinking water treatment. Cr(VI) is chemically reduced to less soluble Cr(III) species by the Fe(II) produced from an iron anode, and XANES spectra indicate that the Cr is entirely Cr(III) in solid-phases produced in electrocoagulation. The dynamics of Cr(VI) removal in electrocoagulation at pH 6 and pH 8 at both oxic and anoxic conditions can be described by a new model that incorporates Fe(II) release from the anode and heterogeneous and homogeneous reduction of Cr(VI) by Fe(II). Heterogeneous Cr(VI) reduction by adsorbed Fe(II) was critical to interpreting Cr(VI) removal at pH 6, and the Fe- and Cr-containing EC product was found to catalyze the redox reaction. Dissolved oxygen (DO) did not observably inhibit Cr(VI) removal because Fe(II) reacts with DO more slowly than it does with Cr(VI), and Cr(VI) removal was faster at higher pH. Even in the presence of common groundwater solutes, iron electrocoagulation lowered Cr(VI) concentrations to levels well below California's 10 μg/L.

Osmium(VI) complexes as a new class of potential anti-cancer agents.

PubMed

Ni, Wen-Xiu; Man, Wai-Lun; Cheung, Myra Ting-Wai; Sun, Raymond Wai-Yin; Shu, Yuan-Lan; Lam, Yun-Wah; Che, Chi-Ming; Lau, Tai-Chu

2011-02-21

A nitridoosmium(VI) complex [Os(VI)(N)(sap)(OH(2))Cl] (H(2)sap = N-salicylidene-2-aminophenol) displays prominent in vitro and in vivo anti-cancer properties, induces S- and G2/M-phase arrest and forms a stable adduct with dianionic 5'-guanosine monophosphate.

Obesity and Sleep-Related Breathing Disorders in Middle East and UAE.

PubMed

Vats, Mayank G; Mahboub, Bassam H; Al Hariri, Hassan; Al Zaabi, Ashraf; Vats, Deepa

2016-01-01

A pandemic of obesity is sweeping all across the globe and the Middle East region also does not remain untouched by this prevailing pandemic. In fact, as per WHO report, Kuwait has the second highest obesity prevalence followed closely by other Middle East (ME) countries, namely, Qatar, Saudi Arabia, and United Arab Emirates (UAE). Apart from direct medical, psychological, and quality of life related adverse effects of obesity, many indirect medical comorbidities, namely, obstructive sleep apnea (OSA), obesity hypoventilation syndrome (OHS), diabetes mellitus (DM), hypertension (HTN), and metabolic syndrome, imposes a significant health burden on the individual and community with consequent morbidity and mortality. The purpose of this review is to shed light on the very high prevalence of obesity, undiagnosed sleep apnea, and other obesity related disorders with discussion of the contributing factors specific to the region including the fair insight into the current status of sleep medicine services in Middle East and UAE despite huge number of patients having undiagnosed sleep disorders. We will also suggest to control this epidemic of obesity and OSA so that the corrective measure could be taken at health ministry level to help people of this region to fight against obesity and related disorders, primarily OSA.

Obesity and Sleep-Related Breathing Disorders in Middle East and UAE

PubMed Central

Mahboub, Bassam H.; Al Hariri, Hassan; Al Zaabi, Ashraf; Vats, Deepa

2016-01-01

A pandemic of obesity is sweeping all across the globe and the Middle East region also does not remain untouched by this prevailing pandemic. In fact, as per WHO report, Kuwait has the second highest obesity prevalence followed closely by other Middle East (ME) countries, namely, Qatar, Saudi Arabia, and United Arab Emirates (UAE). Apart from direct medical, psychological, and quality of life related adverse effects of obesity, many indirect medical comorbidities, namely, obstructive sleep apnea (OSA), obesity hypoventilation syndrome (OHS), diabetes mellitus (DM), hypertension (HTN), and metabolic syndrome, imposes a significant health burden on the individual and community with consequent morbidity and mortality. The purpose of this review is to shed light on the very high prevalence of obesity, undiagnosed sleep apnea, and other obesity related disorders with discussion of the contributing factors specific to the region including the fair insight into the current status of sleep medicine services in Middle East and UAE despite huge number of patients having undiagnosed sleep disorders. We will also suggest to control this epidemic of obesity and OSA so that the corrective measure could be taken at health ministry level to help people of this region to fight against obesity and related disorders, primarily OSA. PMID:28070158

Magnetic solid-phase extraction combined with graphite furnace atomic absorption spectrometry for speciation of Cr(III) and Cr(VI) in environmental waters.

PubMed

Jiang, Hong-mei; Yang, Ting; Wang, Yan-hong; Lian, Hong-zhen; Hu, Xin

2013-11-15

A new approach of magnetic solid phase extraction (MSPE) coupled with graphite furnace atomic absorption spectrometry (GFAAS) has been developed for the speciation of Cr(III) and Cr(VI) using zincon-immobilized silica-coated magnetic Fe3O4 nanoparticles (Zincon-Si-MNPs) as the MSPE absorbent. Cr(III) was quantitatively reserved on the absorbent at pH 9.1 while total Cr was reserved at pH 6.5. The absorbed Cr species were eluted by using 2 mol/L HCl and detected by GFAAS. The concentration of Cr(VI) could be calculated by subtracting Cr(III) from total Cr. All the parameters affecting the separation and extraction efficiency of Cr species such as pH, extraction time, concentration and volume of eluent, sample volume and influence of co-existing ions were systematically examined and the optimized conditions were established accordingly. The detection limit (LOD) of the method was 0.016 and 0.011 ng mL(-1) for Cr(III) and Cr(VI), respectively, with the enrichment factor of 100 and 150. The precisions of this method (Relative standard deviation, RSD, n=7) for Cr(III) and Cr(VI) at 0.1 ng mL(-1) were 6.0% and 6.2%, respectively. In order to validate the proposed method, a certified reference material of environmental water was analyzed, and the result of Cr speciation was in good agreement with the certified value. This MSPE-GFAAS method has been successfully applied for the speciation of Cr(III) and Cr(VI) in lake and tap waters with the recoveries of 88-109% for the spiked samples. Moreover, the MSPE separation mechanism of Cr(III) and Cr(VI) based on their adsorption-desorption on Zincon-Si-MNPs has been explained through various spectroscopic characterization. © 2013 Elsevier B.V. All rights reserved.

Acute coronary syndrome registry from four large centres in United Arab Emirates (UAE-ACS Registry)

PubMed Central

Yusufali, Afzalhussein M; AlMahmeed, Wael; Tabatabai, Sadeq; Rao, Kabad; Binbrek, Azan

2010-01-01

Objective To identify the characteristics, treatments and hospital outcomes of patients diagnosed as having acute coronary syndrome (ACS) in the United Arab Emirates (UAE). Design A 3-year prospective registry. Setting Four tertiary care hospitals in three major cities of UAE from December 2003 to December 2006. Patients 1842 eligible consecutive patients with suspected ACS. Interventions None. Main outcome measures Characteristics, treatments and in-hospital outcomes were recorded. Results The mean age was 50.8±10.0 years, and 93.1% were male. More than half (51%) had ST elevation myocardial infarction (STEMI). The smoking rate was 46.4%, and diabetes was present in 38.9%. Only a minority (17.3%) used the ambulance services. For patients with STEMI, the median symptom to hospital time was 127 (IQR 60–256) min, and the median diagnostic ECG to thrombolysis time was 28 (IQR 16–50) min. Reperfusion in STEMI was in 81.4% (64.8% thrombolysis and 16.6% primary percutaneous coronary intervention). During hospitalisation, only a minority of the patients did not receive antiplatelets, anticoagulants, beta-blockers, ACE inhibitors and statin therapy. In-hospital complications were not common in our registry cohort. In-hospital mortality was 1.68%. Conclusions ACS patients in UAE are young but have higher risk factors such as smoking and diabetes. Almost half present as STEMI. Only a minority use ambulance services. PMID:27325958

Nonisovalent Si-III-V and Si-II-VI alloys: Covalent, ionic, and mixed phases

DOE PAGES

Kang, Joongoo; Park, Ji -Sang; Stradins, Pauls; ...

2017-07-13

In this paper, nonequilibrium growth of Si-III-V or Si-II-VI alloys is a promising approach to obtaining optically more active Si-based materials. We propose a new class of nonisovalent Si 2AlP (or Si 2ZnS) alloys in which the Al-P (or Zn-S) atomic chains are as densely packed as possible in the host Si matrix. As a hybrid of the lattice-matched parent phases, Si2AlP (or Si2ZnS) provides an ideal material system with tunable local chemical orders around Si atoms within the same composition and structural motif. Here, using first-principles hybrid functional calculations, we discuss how the local chemical orders affect the electronicmore » and optical properties of the nonisovalent alloys.« less

One Corner at a Time: Collaborating for Educational Change in the UAE

ERIC Educational Resources Information Center

Sowa, Patience A.; De La Vega, Esperanza

2008-01-01

Education has been one of the highest priorities in the United Arab Emirates (UAE) since it became a country in 1971 under the leadership of the late Sheikh Zayed Bin Sultan Al Nahyan. In 1962, when oil production started in Abu Dhabi, the country had just 20 schools for less than 4,000 students, most of them boys. The discovery of oil became the…

Cr(VI) removal by FeS-coated alumina, silica, and natural sand

NASA Astrophysics Data System (ADS)

Park, M.; Lee, S.; Jeong, H. Y.

2014-12-01

Removal of Cr(VI) was investigated using mackinawite (FeS)-coated mineral sorbents under anoxic conditions. The sorbents included alumina (Al), silica (WS), and natural sand (NS). By analysis of both solution and solid phases, all FeS-coated sorbents were found to reduce Cr(VI) into Cr(III). The sorption extent and mechanism of Cr(VI) strongly depended on the pH conditions. Only at pH 4.5, significant amounts of the dissolved Cr remained in the solution. Titration of dissolved Cr(III) and Fe(III) by NaOH solutions indicated that no bulk-phase precipitation occurred at pH 4.5. Also, the removal of Cr(VI) at pH 4.5 was the greatest by FeS-coated NS. Consistent with these, Cr-K edge EXAFS revealed that Cr was removed by FeS-coated NS via surface precipitation, and that it was immobilized by FeS-coated WS and Al by forming surface clusters. Regardless of FeS-coated sorbents, at pH 7.0 and pH 9.5, the initially added Cr(VI) was quantitatively removed from the solution phase. By EXAFS analysis, the Cr sorption by FeS-coated Al was mainly due to the bulk-phase precipitation of Cr(OH)3(s) or [Cr, Fe](OH)3(s). In case of FeS-coated WS and NS, the short Cr-Cr distance (~2.6 Å) at pH 7.0 and pH 9.5 was not simply accounted for by the bulk precipitation as either hydroxide (rCr-Cr ~ 3.0 Å), and it would rather result from the surface precipitation. Such a difference in the coordination structure among FeS-coated sorbents was likely due to in the lower surface area of the former available for the surface precipitation.

Using Mobile Technology in the Classroom: A Reflection Based on Teaching Experience in UAE

ERIC Educational Resources Information Center

Halaweh, Mohanad

2017-01-01

Smartphones are developing rapidly and continually with new features that make them widely used in many contexts. This paper is to reflect on students' behaviours of using smartphones spontaneously (unplanned use) in the classroom, in a university in Dubai city in UAE. This reflection shall address the following questions: How can the instructors…

Predictors of Academic Performance for Finance Students: Women at Higher Education in the UAE

ERIC Educational Resources Information Center

El Massah, Suzanna Sobhy; Fadly, Dalia

2017-01-01

Purpose: The study uses data drawn from a senior finance major cohort of 78 female undergraduates at Zayed University (ZU)-UAE to investigate factors, which increase the likelihood of achieving better academic performance in an Islamic finance course based on information about socioeconomic background of female students. The paper aims to discuss…

Streptomyces globosus UAE1, a Potential Effective Biocontrol Agent for Black Scorch Disease in Date Palm Plantations.

PubMed

Saeed, Esam E; Sham, Arjun; Salmin, Zeinab; Abdelmowla, Yasmeen; Iratni, Rabah; El-Tarabily, Khaled; AbuQamar, Synan

2017-01-01

Many fungal diseases affect date palm causing considerable losses in date production worldwide. We found that the fungicide Cidely ® Top inhibited the mycelial growth of the soil-borne pathogenic fungus Thielaviopsis punctulata , the causal agent of black scorch disease of date palm, both in vitro and in vivo . Because the use of biocontrol agents (BCAs) can minimize the impact of pathogen control on economic and environmental concerns related to chemical control, we aimed at testing local actinomycete strains isolated from the rhizosphere soil of healthy date palm cultivated in the United Arab Emirates (UAE) against T. punctulata . The selected isolate can thus be used as a potential agent for integrated disease management programs. In general, the BCA showed antagonism in vitro and in greenhouse experiments against this pathogen. The most promising actinomycete isolate screened showed the highest efficacy against the black scorch disease when applied before or at the same time of inoculation with T. punctulata , compared with BCA or fungicide application after inoculation. The nucleotide sequence and phylogenetic analyses using the 16 S ribosomal RNA gene with other Streptomyces spp. in addition to morphological and cultural characteristics revealed that the isolated UAE strain belongs to Streptomyces globosus UAE1. The antagonistic activity of S. globosus against T. punctulata , was associated with the production by this strain of diffusible antifungal metabolites i.e., metabolites that can inhibit mycelial growth of the pathogen. This was evident in the responses of the vegetative growth of pure cultures of the pathogen when exposed to the culture filtrates of the BCA. Altogether, the pathogenicity tests, disease severity indices and mode of action tests confirmed that the BCA was not only capable of suppressing black scorch disease symptoms, but also could prevent the spread of the pathogen, as a potential practical method to improve disease management in the

Inhibition of nitrate reduction by chromium (VI) in anaerobic soil microcosms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kourtev, P. S.; Nakatsu, C. H.; Konopka, Allan

2009-10-01

Chromium (VI) is often found as a co-contaminant at sites polluted with organic compounds. We used microcosms amended with glucose or protein, nitrate and increasing concentrations of chromium to study nitrate reduction in Cr(VI) polluted soils. Organic carbon stimulated bacterial activity, but the addition of Cr(VI) caused a lag and then slower rates 5 of CO2 accumulation. Nitrate reduction only occurred after Cr(VI) had been reduced. Bacterial activity was again inhibited when Cr(VI) was added a second time; thus not all Cr-sensitive bacteria were removed in the first phase. Glucose and protein selected for relatively similar bacterial communities, as assayedmore » by PCR-DGGE of the 16S rRNA gene; this selection was modified by the addition of 10 Cr(VI). Cr-resistant bacteria isolated from microcosms were closely related to members of Bacillus, Enterococcus and Propionibacterium sp. Our results indicate that carbon utilization and nitrate reduction in these soils in the presence of Cr(VI) are contingent upon the reduction of the added heavy metal by a limited subset of the bacterial community. The amount of Cr(VI) required to inhibit nitrate reduction was 10-fold less than for aerobic catabolism of the same 15 substrate. We hypothesize that the resistance level of a microbial process is directly related to the diversity of microbes capable of conducting it.« less

Towards a Personality Understanding of Information Technology Students and Their IT Learning in UAE University

ERIC Educational Resources Information Center

Al-Qirim, Nabeel; Rouibah, Kamel; Tarhini, Ali; Serhani, Mohamed Adel; Yammahi, Aishah Rashid; Yammahi, Maraim Ahmed

2018-01-01

This research investigates the personality characteristics of Information Technology students (CIT) in UAE University (UAEU) and how such features impact their IT learning. To achieve this objective, this research attempts to explain the impact of the Big-5 factors on learning using survey research. Results from 179 respondents suggested that…

The UAE Rainfall Enhancement Assessment Program: Implications of Thermodynamic Profiles on the Development of Precipitation in Convective Clouds over the Oman Mountains

NASA Astrophysics Data System (ADS)

Breed, D.; Bruintjes, R.; Jensen, T.; Salazar, V.; Fowler, T.

2005-12-01

During the winter and summer seasons of 2001 and 2002, data were collected to assess the efficacy of cloud seeding to enhance precipitation in the United Arab Emirates (UAE). The results of the feasibility study concluded: 1) that winter clouds in the UAE rarely produced conditions amenable to hygroscopic cloud seeding; 2) that summer convective clouds developed often enough, particularly over the Oman Mountains (e.g., the Hajar Mountains along the eastern UAE border and into Oman) to justify a randomized seeding experiment; 3) that collecting quantitative radar observations continues to be a complex but essential part of evaluating a cloud seeding experiment; 4) that successful flight operations would require solving several logistical issues; and 5) that several scientific questions would need to be studied in order to fully evaluate the efficacy and feasibility of hygroscopic cloud seeding, including cloud physical responses, radar-derived rainfall estimates as related to rainfall at the ground, and hydrological impacts. Based on these results, the UAE program proceeded through the design and implemention of a randomized hygroscopic cloud seeding experiment during the summer seasons to statistically quantify the potential for cloud seeding to enhance rainfall, specifically over the UAE and Oman Mountains, while collecting concurrent and separate physical measurements to support the statistical results and provide substantiation for the physical hypothesis. The randomized seeding experiment was carried out over the summers of 2003 and 2004, and a total of 134 cases were treated over the two summer seasons, of which 96 met the analysis criteria established in the experimental design of the program. The statistical evaluation of these cases yielded largely inconclusive results. Evidence will show that the thermodynamic profile had a large influence on storm characteristics and on precipitation development. This in turn provided a confounding factor in the conduct

Bioreduction of U(VI) and stability of immobilized uranium under suboxic conditions.

PubMed

Hu, Nan; Ding, De-xin; Li, Shi-mi; Tan, Xiang; Li, Guang-yue; Wang, Yong-dong; Xu, Fei

2016-04-01

In order to study the bioreduction of U(VI) and stability of immobilized uranium under suboxic conditions, microcosm were amended with ethanol, lactate and glucose, and incubated under suboxic conditions. During the incubation, total dissolved U in amended microcosms decreased from 0.95 mg/L to 0.03 mg/L. Pyrosequencing results showed that, the proportion of anaerobic microorganisms capable of reducing U(VI) under suboxic conditions was small compared with that under anoxic conditions; the proportion of aerobic and facultative anaerobic microorganisms capable of consuming the dissolved oxygen was large; and some of the facultative anaerobic microorganisms could reduce U(VI). These results indicated that different microbial communities were responsible for the bioreduction of U(VI) under suboxic and anoxic conditions. After the electron donors were exhausted, total dissolved U in the amended microcosms remained unchanged, while the U(VI)/U(IV) ratio in the solid phase of sediments increased obviously. This implied that the performance of bioreduction of the U(VI) can be maintained under suboxic condition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gis-Based Wind Farm Site Selection Model Offshore Abu Dhabi Emirate, Uae

NASA Astrophysics Data System (ADS)

Saleous, N.; Issa, S.; Mazrouei, J. Al

2016-06-01

The United Arab Emirates (UAE) government has declared the increased use of alternative energy a strategic goal and has invested in identifying and developing various sources of such energy. This study aimed at assessing the viability of establishing wind farms offshore the Emirate of Abu Dhabi, UAE and to identify favourable sites for such farms using Geographic Information Systems (GIS) procedures and algorithms. Based on previous studies and on local requirements, a set of suitability criteria was developed including ocean currents, reserved areas, seabed topography, and wind speed. GIS layers were created and a weighted overlay GIS model based on the above mentioned criteria was built to identify suitable sites for hosting a new offshore wind energy farm. Results showed that most of Abu Dhabi offshore areas were unsuitable, largely due to the presence of restricted zones (marine protected areas, oil extraction platforms and oil pipelines in particular). However, some suitable sites could be identified, especially around Delma Island and North of Jabal Barakah in the Western Region. The environmental impact of potential wind farm locations and associated cables on the marine ecology was examined to ensure minimal disturbance to marine life. Further research is needed to specify wind mills characteristics that suit the study area especially with the presence of heavy traffic due to many oil production and shipping activities in the Arabian Gulf most of the year.

RANS Simulation (Actuator Disk Model[ADM]) of the NREL Phase VI wind turbine modeled as MHK Turbine

DOE Data Explorer

Javaherchi, Teymour

2016-06-08

Attached are the .cas and .dat files for the Reynolds Averaged Navier-Stokes (RANS) simulation of a single lab-scaled DOE RM1 turbine implemented in ANSYS FLUENT CFD-package. In this case study the flow field around and in the wake of the NREL Phase VI wind turbine, modeled is MHK turbine, is simulated using Actuator Disk Model (a.k.a Porous Media) by solving RANS equations coupled with a turbulence closure model. It should be highlighted that in this simulation the actual geometry of the rotor blade is not modeled. The effect of turbine rotating blades are modeled using the Actuator Disk Theory (see the stated section of attached M.Sc. thesis for more details).

Design of a new concentrated photovoltaic system under UAE conditions

NASA Astrophysics Data System (ADS)

Hachicha, Ahmed Amine; Tawalbeh, Muahammad

2017-06-01

Concentrated Photovoltaic Systems (CPVs) are considered one of the innovative designs for concentrated solar power applications. By concentrating the incident radiation, the solar cells will be able to produce much more electricity compared to conventional PV systems. However, the temperature of the solar cells increases significantly with concentration. Therefore, cooling of the solar cells will be needed to maintain high conversion efficiency. In this work, a novel design of CPV system is proposed and implemented under UAE conditions for electricity generation and hot water production. The proposed design integrates a water cooling system and PV system to optimize both the electrical and thermal performances of the CPV system.

Understanding the strong intervening O VI absorber at zabs ˜ 0.93 towards PG1206+459

NASA Astrophysics Data System (ADS)

Rosenwasser, B.; Muzahid, S.; Charlton, J. C.; Kacprzak, G. G.; Wakker, B. P.; Churchill, C. W.

2018-05-01

We have obtained new observations of the partial Lyman limit absorber at zabs=0.93 towards quasar PG 1206+459, and revisit its chemical and physical conditions. The absorber, with N({H I})˜ 10^{17.0} cm-2 and absorption lines spread over ≳1000 km s-1 in velocity, is one of the strongest known O VI absorbers at \\log N({{O VI}})= 15.54 ± 0.17. Our analysis makes use of the previously known low- (e.g. Mg II), intermediate- (e.g. Si IV), and high-ionization (e.g. C IV, N V, Ne VIII) metal lines along with new Hubble Space Telescope (HST)/Cosmic Origins Spectrograph (COS) observations that cover O VI and an HST/ACS image of the quasar field. Consistent with previous studies, we find that the absorber has a multiphase structure. The low-ionization phase arises from gas with a density of \\log (n_H/cm^{-3})˜ -2.5 and a solar to supersolar metallicity. The high-ionization phase stems from gas with a significantly lower density, i.e. \\log (n_H/cm^{-3}) ˜ -3.8, and a near-solar to solar metallicity. The high-ionization phase accounts for all of the absorption seen in C IV, N V, and O VI. We find the the detected Ne VIII, reported by Tripp et al. (2011), is best explained as originating in a stand-alone collisionally ionized phase at T˜ 10^{5.85} K, except in one component in which both O VI and Ne VIII can be produced via photoionization. We demonstrate that such strong O VI absorption can easily arise from photoionization at z ≳ 1, but that, due to the decreasing extragalactic UV background radiation, only collisional ionization can produce large O VI features at z ˜ 0. The azimuthal angle of ˜88° of the disc of the nearest (68 kpc) luminous (1.3L*) galaxy at zgal = 0.9289, which shows signatures of recent merger, suggests that the bulk of the absorption arises from metal enriched outflows.

Non-enzymatic U(VI) interactions with biogenic mackinawite

NASA Astrophysics Data System (ADS)

Veeramani, H.; Qafoku, N. P.; Kukkadapu, R. K.; Murayama, M.; Hochella, M. F.

2011-12-01

Reductive immobilization of hexavalent uranium [U(VI)] by stimulation of dissimilatory metal and/or sulfate reducing bacteria (DMRB or DSRB) has been extensively researched as a remediation strategy for subsurface U(VI) contamination. These bacteria derive energy by reducing oxidized metals as terminal electron acceptors, often utilizing organic substrates as electron donors. Thus, when evaluating the potential for in-situ uranium remediation in heterogeneous subsurface media, it is important to understand how the presence of alternative electron acceptors such as Fe(III) and sulfate affect U(VI) remediation and the long term behavior and reactivity of reduced uranium. Iron, an abundant subsurface element, represents a substantial sink for electrons from DMRB, and the reduction of Fe(III) leads to the formation of dissolved Fe(II) or to reactive biogenic Fe(II)- and mixed Fe(II)/Fe(III)- mineral phases. Consequently, abiotic U(VI) reduction by reactive forms of biogenic Fe(II) minerals could be a potentially important process for uranium immobilization. In our study, the DMRB Shewanella putrefaciens CN32 was used to synthesize a biogenic Fe(II)-bearing sulfide mineral: mackinawite, that has been characterized by XRD, SEM, HRTEM and Mössbauer spectroscopy. Batch experiments involving treated biogenic mackinawite and uranium (50:1 molar ratio) were carried out at room temperature under strict anoxic conditions. Following complete removal of uranium from solution, the biogenic mackinawite was analyzed by a suite of analytical techniques including XAS, HRTEM and Mössbauer spectroscopy to determine the speciation of uranium and investigate concomitant Fe(II)-phase transformation. Determining the speciation of uranium is critical to success of a remediation strategy. The present work elucidates non-enzymatic/abiotic molecular scale redox interactions between biogenic mackinawite and uranium.

Chromium sorption and Cr(VI) reduction to Cr(III) by grape stalks and yohimbe bark.

PubMed

Fiol, Núria; Escudero, Carlos; Villaescusa, Isabel

2008-07-01

In this work, two low cost sorbents, grape stalks and yohimbe bark wastes were used to remove Cr(VI) and Cr(III) from aqueous solutions. Batch experiments were designed to obtain Cr(VI) and Cr(III) sorption data. The mechanism of Cr(III) and Cr(VI) removal and Cr(VI) reduction to Cr(III) by the two vegetable wastes, has been investigated. Fourier transform infrared rays (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis on solid phase were performed to determine the main functional groups that might be involved in metal uptake and to confirm the presence of Cr(III) on the sorbent, respectively. Results put into evidence that both sorbents are able to reduce Cr(VI) to its trivalent form.

VizieR Online Data Catalog: OGLE II. VI photometry of Galactic Bulge (Udalski+, 2002)

NASA Astrophysics Data System (ADS)

Udalski, A.; Szymanski, M.; Kubiak, M.; Pietrzynski, G.; Soszynski, I.; Wozniak, P.; Zebrun, K.; Szewczyk, O.; Wyrzykowski, L.

2003-09-01

We present the VI photometric maps of the Galactic bulge. They contain VI photometry and astrometry of about 30 million stars from 49 fields of 0.225 square degree each in the Galactic center region. The data were collected during the second phase of the OGLE microlensing project. We discuss the accuracy of data and present color-magnitude diagrams of selected fields observed by OGLE in the Galactic bulge. The VI maps of the Galactic bulge are accessible electronically for the astronomical community from the OGLE Internet archive (2 data files).

THE ATM-SMC1 PATHWAY IS ESSENTIAL FOR ACTIVATION OF THE CHROMIUM[VI]-INDUCED S-PHASE CHECKPOINT

EPA Science Inventory

Hexavalent chromium (Cr[VI] is a common industrial waste product, an environmental pollutant, and a recognized human carcinogen. Following cellular uptake, Cr[VI] can cause DNA damage, however, the mechanisims by which mammalian cells respond to Cr-induced DNA damage remain to b...

Evaluation of land capability and suitability for irrigated agriculture in the Emirate of Abu Dhabi, UAE, using an integrated AHP-GIS model

NASA Astrophysics Data System (ADS)

Aldababseh, A.; Temimi, M.; Maghelal, P.; Branch, O.; Wulfmeyer, V.

2017-12-01

The rapid economic development and high population growth in the United Arab Emirates (UAE) have impacted utilization and management of agricultural land. The development of large-scale agriculture in unsuitable areas can severely impact groundwater resources in the UAE. More than 60% of UAE's water resources are being utilized by the agriculture, forestry, and urban greenery sectors. However, the contribution of the agricultural sector to the national GDP is negligible. Several programs have been introduced by the government aimed at achieving sustainable agriculture whilst preserving valuable water resources. Local subsistence farming has declined considerably during the past few years, due to low soil moisture content, sandy soil texture, lack of arable land, natural climatic disruptions, water shortages, and declined rainfall. The limited production of food and the continuing rise in the food prices on a global and local level are expected to increase low-income households' vulnerability to food insecurity. This research aims at developing a suitability index for the evaluation and prioritization of areas in the UAE for large-scale agriculture. The AHP-GIS integrated model developed in this study facilitates a step by step aggregation of a large number of datasets representing the most important criteria, and the generation of agricultural suitability and land capability maps. To provide the necessary criteria to run the model, a comprehensive geospatial database was built, including climate conditions, water potential, soil capabilities, topography, and land management. A hieratical structure is built as a decomposition structure that includes all criteria and sub-criteria used to define land suitability based on literature review and experts' opinions. Pairwise comparisons matrix are used to calculate criteria' weights. The GIS Model Builder function is used to integrate all spatial processes to model land suitability. In order to preserve some flexibility

Evaluation of land capability and suitability for irrigated agriculture in the Emirate of Abu Dhabi, UAE, using an integrated AHP-GIS model

NASA Astrophysics Data System (ADS)

Aldababseh, Amal; Temimi, Marouane; Maghelal, Praveen; Branch, Oliver; Wulfmeyer, Volker

2017-12-01

The rapid economic development and high population growth in the United Arab Emirates (UAE) have impacted utilization and management of agricultural land. The development of large-scale agriculture in unsuitable areas can severely impact groundwater resources in the UAE. More than 60% of UAE's water resources are being utilized by the agriculture, forestry, and urban greenery sectors. However, the contribution of the agricultural sector to the national GDP is negligible. Several programs have been introduced by the government aimed at achieving sustainable agriculture whilst preserving valuable water resources. Local subsistence farming has declined considerably during the past few years, due to low soil moisture content, sandy soil texture, lack of arable land, natural climatic disruptions, water shortages, and declined rainfall. The limited production of food and the continuing rise in the food prices on a global and local level are expected to increase low-income households' vulnerability to food insecurity. This research aims at developing a suitability index for the evaluation and prioritization of areas in the UAE for large-scale agriculture. The AHP-GIS integrated model developed in this study facilitates a step by step aggregation of a large number of datasets representing the most important criteria, and the generation of agricultural suitability and land capability maps. To provide the necessary criteria to run the model, a comprehensive geospatial database was built, including climate conditions, water potential, soil capabilities, topography, and land management. A hierarchical structure is built as a decomposition structure that includes all criteria and sub-criteria used to define land suitability based on literature review and experts' opinions. Pairwise comparisons matrix are used to calculate criteria' weights. The GIS Model Builder function is used to integrate all spatial processes to model land suitability. In order to preserve some flexibility

Economic risk and efficiency assessment of fisheries in Abu-Dhabi, United Arab Emirates (UAE): A stochastic approach

USDA-ARS?s Scientific Manuscript database

The fishing industry in Abu-Dhabi, United Arab Emirates (UAE) plays an important role in diversifying food sources in order to enhance national food security. The fishing industry is facing increasing risk that may impact the sustainability (i.e., quantity and quality) of the fish caught and consume...

Ferrrate(VI) and freeze-thaw treatment for oxidation of hormones and inactivation of fecal coliforms in sludge.

PubMed

Diak, James; Örmeci, Banu

2017-04-01

This study examined the individual and combined effects of potassium ferrate(VI) additions and freeze-thaw conditioning for the treatment and dewatering of wastewater sludge in cold climates, with particular focus on the inactivation of fecal coliforms and oxidation of estrogens, androgens, and progestogens. The first phase of the study evaluated the effects of potassium ferrate(VI) pre-treatment followed by freeze-thaw at -20 °C using a low (0.5 g/L) and high (5.0 g/L) dose of potassium ferrate(VI). The results showed that pre-treatment of anaerobically digested sludge with 5 g/L of potassium ferrate(VI) reduced the concentration of fecal coliforms in the sludge cake to below 100 MPN/g DS. The second phase evaluated the ability of ferrate(VI) to oxidise selected hormones in sludge. Anaerobically digested sludge samples were spiked with 10 different hormones: estrone (E1), 17α-estradiol, 17β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2), equilin, mestranol, testosterone, norethindrone and norgestrel in two groups of low (3-75 ng/mL) and high (12-300 ng/L) concentration ranges of hormones. The samples were treated with either 0.5 or 1.0 g/L of potassium ferrate(VI), and hormone concentrations were measured again after treatment. Potassium ferrate(VI) additions as low as 1.0 g/L reduced the concentration of estrogens in sludge. Potassium ferrate(VI) additions of 0.5 and 1.0 g/L were less effective at reducing the concentrations of androgens and progestogens. Increasing ferrate(VI) dose would likely result in more substantial decreases in the concentrations of fecal coliforms and hormones. The results of this study indicate that the combined use of freeze-thaw and ferrate(VI) has the potential to provide a complete sludge treatment solution in cold regions.

Higher Education and Development in Arab Oil Exporters: The UAE [United Arab Emirates] in Comparative Perspective.

ERIC Educational Resources Information Center

Vandewalle, Diederik

As exporters of oil in the Middle East and throughout the world, the United Arab Emirates (UAE) must address the following challenges in the area of development and economic growth: (1) an increasingly integrated world economy in which technology and knowledge will be paramount; (2) the need to diversify its economy from a natural resource-based…

Exploratory study into the awareness of heart diseases among Emirati women (UAE) and their health seeking behaviour- a qualitative study.

PubMed

Khan, Sarah; Khoory, Ayesha; Al Zaffin, Dhabia; Al Suwaidi, Meera

2016-11-07

Cardiovascular diseases were the leading cause of death in women in the United Arab Emirates (UAE) in 2010. The UAE is expected to experience a tripling of heart diseases in the next two decades as risk factors for heart diseases increase. Research shows that first year survival rates of younger women suffering from a heart attack are lower than in men. Women present with a wider range of symptoms for heart diseases than men; non-recognition of atypical symptoms may explain the delay in seeking treatment and poor prognosis following heart diseases in women. No known study on awareness of heart diseases among women has been carried out in the Middle Eastern region. Social constructionist and interpretivist epistemological approaches have been considered in this qualitative study to explore the awareness of heart diseases and the health seeking behavior of Emirati women. Convenience sampling was used to recruit 41 Emirati women. Three focus groups and six in-depth semi-structured interviews were conducted to obtain data. Thematic content analysis was applied to the data following transcription and translation of recordings. Emirati women had limited knowledge on heart diseases. Women were generally unaware of the atypical symptoms, commonly experienced by women however they identified most risk factors associated with heart diseases. Lack of awareness of disease severity and symptoms, sociocultural influences and distrust in the healthcare system were considered the main barriers to seeking prompt treatment. This study clearly identified gaps and inaccuracies in knowledge of heart diseases, which could contribute to delayed health seeking action and possibly poorer prognosis among Emirati women. Absence of initiatives to educate women on cardiovascular diseases in UAE has erroneously deemed it a less serious concern among Emirati women. The findings from this study provide clear indications of the need to increase accountability of the healthcare system and to

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowman, Stephen M

2008-09-01

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-VImore » 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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schreck, S. J.; Schepers, J. G.

Continued inquiry into rotor and blade aerodynamics remains crucial for achieving accurate, reliable prediction of wind turbine power performance under yawed conditions. To exploit key advantages conferred by controlled inflow conditions, we used EU-JOULE DATA Project and UAE Phase VI experimental data to characterize rotor power production under yawed conditions. Anomalies in rotor power variation with yaw error were observed, and the underlying fluid dynamic interactions were isolated. Unlike currently recognized influences caused by angled inflow and skewed wake, which may be considered potential flow interactions, these anomalies were linked to pronounced viscous and unsteady effects.

Unconventional Rotor Power Response to Yaw Error Variations

DOE PAGES

Schreck, S. J.; Schepers, J. G.

2014-12-16

Continued inquiry into rotor and blade aerodynamics remains crucial for achieving accurate, reliable prediction of wind turbine power performance under yawed conditions. To exploit key advantages conferred by controlled inflow conditions, we used EU-JOULE DATA Project and UAE Phase VI experimental data to characterize rotor power production under yawed conditions. Anomalies in rotor power variation with yaw error were observed, and the underlying fluid dynamic interactions were isolated. Unlike currently recognized influences caused by angled inflow and skewed wake, which may be considered potential flow interactions, these anomalies were linked to pronounced viscous and unsteady effects.

Am(VI) Extraction Final Report: FY16

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mincher, Bruce Jay; Grimes, Travis Shane; Tillotson, Richard Dean

This report summarizes activities related to hexavalent Am extraction for FY16, in completion of FCR&D Milestone M3FT-16IN030103027. Activities concentrated on three areas of research: 1) centrifugal contactor hot testing, 2) Am(VI) stability studies, and 3) alternative oxidant studies. A brief summary of each task follows. Hot Testing: A new engineering-scale oxidation and solvent extraction test bed was built at Idaho National Laboratory to allow for solvent extraction testing of minor actinide separation concepts. The test bed consists of an oxidation vessel, filtration apparatus, four, 3D printed, 2-cm diameter centrifugal contactors, feed/product vessels, and sample ports. This system replaced the previousmore » 3 stage, 5-cm contactor test bed that was used for the initial testing in FY14. In the FY16 hot test, a feed simulant was spiked with 243Am and 139Ce and treated with 60 g/L sodium bismuthate for two hours to oxidize the Am(III) to Am(VI). This solution was then pumped through a filter and into the four-stage centrifugal contactor setup. The organic phase solvent formulation was 1 M diethylhexylbutyramide (DEHBA)/dodecane. The test showed that Am(VI) was produced by bismuthate oxidation and the residual oxidant was successfully filtered without back pressure buildup. Sixty-four percent of Am was extracted in the contactors using DEHBA. Both Am and Ce were quantitatively stripped by 0.1 M H2O2. Successful demonstration of the utility of small, printable contactors suggests that hot testing of separations concepts can now be conducted more often, since it is cheaper, generates less waste, and entails much less radcon risk than previous testing. Am(VI) stability: A rigorous examination of reagents was conducted to determine if contaminants could interfere with Am oxidation and extraction. An series of DAm measurements showed that bismuthate particle size, water source, acid quality, and DAAP batch or pre-treatment had little effect on extraction

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

USGS Publications Warehouse

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

2011-01-01

very small fraction of the total solid phase Cr, they are a potentially important source for Cr(VI) to groundwater. Enhanced groundwater recharge through the vadose zone due to irrigation could carry Cr(VI) from the vadose zone to the groundwater and may be the mechanism responsible for the correlation observed between elevated Cr(VI) and NO3- source concentrations in previously published data for valley groundwaters. Incubation of a valley subsoil showed a Cr(VI) production rate of 24 μg kg−1 a−1 suggesting that field Cr(VI) concentrations could be regenerated annually. Increased Cr(VI) production rates in H+-amended soil incubations indicate that soil acidification processes such as nitrification of ammonium in fertilizers could potentially increase the occurrence of geogenic Cr(VI) in groundwater. Thus, despite the natural origin of the Cr, Cr(VI) generation in the Sacramento Valley soils and sediments has the potential to be influenced by human activities.

Kinetics and mechanisms of the oxidation of iodide and bromide in aqueous solutions by a trans-dioxoruthenium(VI) complex.

PubMed

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

2008-08-04

The kinetics and mechanisms of the oxidation of I (-) and Br (-) by trans-[Ru (VI)(N 2O 2)(O) 2] (2+) have been investigated in aqueous solutions. The reactions have the following stoichiometry: trans-[Ru (VI)(N 2O 2)(O) 2] (2+) + 3X (-) + 2H (+) --> trans-[Ru (IV)(N 2O 2)(O)(OH 2)] (2+) + X 3 (-) (X = Br, I). In the oxidation of I (-) the I 3 (-)is produced in two distinct phases. The first phase produces 45% of I 3 (-) with the rate law d[I 3 (-)]/dt = ( k a + k b[H (+)])[Ru (VI)][I (-)]. The remaining I 3 (-) is produced in the second phase which is much slower, and it follows first-order kinetics but the rate constant is independent of [I (-)], [H (+)], and ionic strength. In the proposed mechanism the first phase involves formation of a charge-transfer complex between Ru (VI) and I (-), which then undergoes a parallel acid-catalyzed oxygen atom transfer to produce [Ru (IV)(N 2O 2)(O)(OHI)] (2+), and a one electron transfer to give [Ru (V)(N 2O 2)(O)(OH)] (2+) and I (*). [Ru (V)(N 2O 2)(O)(OH)] (2+) is a stronger oxidant than [Ru (VI)(N 2O 2)(O) 2] (2+) and will rapidly oxidize another I (-) to I (*). In the second phase the [Ru (IV)(N 2O 2)(O)(OHI)] (2+) undergoes rate-limiting aquation to produce HOI which reacts rapidly with I (-) to produce I 2. In the oxidation of Br (-) the rate law is -d[Ru (VI)]/d t = {( k a2 + k b2[H (+)]) + ( k a3 + k b3[H (+)]) [Br (-)]}[Ru (VI)][Br (-)]. At 298.0 K and I = 0.1 M, k a2 = (2.03 +/- 0.03) x 10 (-2) M (-1) s (-1), k b2 = (1.50 +/- 0.07) x 10 (-1) M (-2) s (-1), k a3 = (7.22 +/- 2.19) x 10 (-1) M (-2) s (-1) and k b3 = (4.85 +/- 0.04) x 10 (2) M (-3) s (-1). The proposed mechanism involves initial oxygen atom transfer from trans-[Ru (VI)(N 2O 2)(O) 2] (2+) to Br (-) to give trans-[Ru (IV)(N 2O 2)(O)(OBr)] (+), which then undergoes parallel aquation and oxidation of Br (-), and both reactions are acid-catalyzed.

Mixture distributions of wind speed in the UAE

NASA Astrophysics Data System (ADS)

Shin, J.; Ouarda, T.; Lee, T. S.

2013-12-01

Wind speed probability distribution is commonly used to estimate potential wind energy. The 2-parameter Weibull distribution has been most widely used to characterize the distribution of wind speed. However, it is unable to properly model wind speed regimes when wind speed distribution presents bimodal and kurtotic shapes. Several studies have concluded that the Weibull distribution should not be used for frequency analysis of wind speed without investigation of wind speed distribution. Due to these mixture distributional characteristics of wind speed data, the application of mixture distributions should be further investigated in the frequency analysis of wind speed. A number of studies have investigated the potential wind energy in different parts of the Arabian Peninsula. Mixture distributional characteristics of wind speed were detected from some of these studies. Nevertheless, mixture distributions have not been employed for wind speed modeling in the Arabian Peninsula. In order to improve our understanding of wind energy potential in Arabian Peninsula, mixture distributions should be tested for the frequency analysis of wind speed. The aim of the current study is to assess the suitability of mixture distributions for the frequency analysis of wind speed in the UAE. Hourly mean wind speed data at 10-m height from 7 stations were used in the current study. The Weibull and Kappa distributions were employed as representatives of the conventional non-mixture distributions. 10 mixture distributions are used and constructed by mixing four probability distributions such as Normal, Gamma, Weibull and Extreme value type-one (EV-1) distributions. Three parameter estimation methods such as Expectation Maximization algorithm, Least Squares method and Meta-Heuristic Maximum Likelihood (MHML) method were employed to estimate the parameters of the mixture distributions. In order to compare the goodness-of-fit of tested distributions and parameter estimation methods for

Study of Cr(VI) adsorption onto magnetite nanoparticles using synchrotron-based X-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

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.

Mobilization of Cr(VI) from chromite ore processing residue through acid treatment.

PubMed

Tinjum, James M; Benson, Craig H; Edil, Tuncer B

2008-02-25

Batch leaching studies on chromite ore processing residue (COPR) were performed using acids to investigate leaching of hexavalent chromium, Cr(VI), with respect to particle size, reaction time, and type of acid (HNO(3) and H(2)SO(4)). Aqueous Cr(VI) is maximized at approximately 0.04 mol Cr(VI) per kg of dry COPR at pH 7.6-8.1. Cr(VI) mobilized more slowly for larger particles, and the pH increased with time and increased more rapidly for smaller particles, suggesting that rate limitations occur in the solid phase. With H(2)SO(4), the pH stabilized at a higher value (8.8 for H(2)SO(4) vs. 8.0 for HNO(3)) and more rapidly (16 h vs. 30 h), and the differences in pH for different particle sizes were smaller. The acid neutralization capacity (ANC) of COPR is very large (8 mol HNO(3) per kg of dry COPR for a stable eluate pH of 7.5). Changes to the elemental and mineralogical composition and distribution in COPR particles after mixing with acid indicate that Cr(VI)-bearing solids dissolved. However, concentrations of Cr(VI) >2800 mg kg(-1) (>50% of the pre-treatment concentration) were still found after mixing with acid, regardless of the particle size, reaction time, or type of acid used. The residual Cr(VI) appears to be partially associated with poorly-ordered Fe and Al oxyhydroxides that precipitated in the interstitial areas of COPR particles. Remediation strategies that use HNO(3) or H(2)SO(4) to neutralize COPR or to maximize Cr(VI) in solution are likely to require extensive amounts of acid, may not mobilize all of the Cr(VI), and may require extended contact time, even under well-mixed conditions.

Injury Risk Assessment of Extravehicular Mobility Unit (EMU) Phase VI and Series 4000 Gloves During Extravehicular Activity (EVA) Hand Manipulation Tasks

NASA Technical Reports Server (NTRS)

Kilby, Melissa

2015-01-01

Functional Extravehicular Mobility Units (EMUs) with high precision gloves are essential for the success of Extravehicular Activity (EVA). Previous research done at NASA has shown that total strength capabilities and performance are reduced when wearing a pressurized EMU. The goal of this project was to characterize the human-space suit glove interaction and assess the risk of injury during common EVA hand manipulation tasks, including pushing, pinching and gripping objects. A custom third generation sensor garment was designed to incorporate a combination of sensors, including force sensitive resistors, strain gauge sensors, and shear force sensors. The combination of sensors was used to measure the forces acting on the finger nails, finger pads, finger tips, as well as the knuckle joints. In addition to measuring the forces, data was collected on the temperature, humidity, skin conductance, and blood perfusion of the hands. Testing compared both the Phase VI and Series 4000 glove against an ungloved condition. The ungloved test was performed wearing the sensor garment only. The project outcomes identified critical landmarks that experienced higher workloads and are more likely to suffer injuries. These critical landmarks varied as a function of space suit glove and task performed. The results showed that less forces were acting on the hands while wearing the Phase VI glove as compared to wearing the Series 4000 glove. Based on our findings, the engineering division can utilize these methods for optimizing the current space suit glove and designing next generation gloves to prevent injuries and optimize hand mobility and comfort.

Efficacy and immunogenicity of a Vi-tetanus toxoid conjugate vaccine in the prevention of typhoid fever using a controlled human infection model of Salmonella Typhi: a randomised controlled, phase 2b trial.

PubMed

Jin, Celina; Gibani, Malick M; Moore, Maria; Juel, Helene B; Jones, Elizabeth; Meiring, James; Harris, Victoria; Gardner, Jonathan; Nebykova, Anna; Kerridge, Simon A; Hill, Jennifer; Thomaides-Brears, Helena; Blohmke, Christoph J; Yu, Ly-Mee; Angus, Brian; Pollard, Andrew J

2017-12-02

Salmonella enterica serovar Typhi (S Typhi) is responsible for an estimated 20 million infections and 200 000 deaths each year in resource poor regions of the world. Capsular Vi-polysaccharide-protein conjugate vaccines (Vi-conjugate vaccines) are immunogenic and can be used from infancy but there are no efficacy data for the leading candidate vaccine being considered for widespread use. To address this knowledge gap, we assessed the efficacy of a Vi-tetanus toxoid conjugate vaccine using an established human infection model of S Typhi. In this single-centre, randomised controlled, phase 2b study, using an established outpatient-based human typhoid infection model, we recruited healthy adult volunteers aged between 18 and 60 years, with no previous history of typhoid vaccination, infection, or prolonged residency in a typhoid-endemic region. Participants were randomly assigned (1:1:1) to receive a single dose of Vi-conjugate (Vi-TT), Vi-polysaccharide (Vi-PS), or control meningococcal vaccine with a computer-generated randomisation schedule (block size 6). Investigators and participants were masked to treatment allocation, and an unmasked team of nurses administered the vaccines. Following oral ingestion of S Typhi, participants were assessed with daily blood culture over a 2-week period and diagnosed with typhoid infection when meeting pre-defined criteria. The primary endpoint was the proportion of participants diagnosed with typhoid infection (ie, attack rate), defined as persistent fever of 38°C or higher for 12 h or longer or S Typhi bacteraemia, following oral challenge administered 1 month after Vi-vaccination (Vi-TT or Vi-PS) compared with control vaccination. Analysis was per protocol. This trial is registered with ClinicalTrials.gov, number NCT02324751, and is ongoing. Between Aug 18, 2015, and Nov 4, 2016, 112 participants were enrolled and randomly assigned; 34 to the control group, 37 to the Vi-PS group, and 41 to the Vi-TT group. 103 participants

Reflections on the Reggio Emilia Approach as Inspiration for Early Childhood Teacher Education in Abu Dhabi, UAE

ERIC Educational Resources Information Center

Baker, Fiona S.

2015-01-01

This article discusses a teacher educator's reflections on her participation in an international study group and visits to the infant-toddler and pre-schools of Reggio Emilia, Italy, as inspiration for early childhood teacher education in Abu Dhabi, UAE. The following five themes are reflected on, for teacher education in the context of Abu Dhabi:…

Attitude towards, and Awareness of Using ICT in Classrooms: A Case of Expatriate Indian Teachers in UAE

ERIC Educational Resources Information Center

Bindu, C. N.

2017-01-01

It is a widely accepted fact that ICT integration in education offers a wider opportunity for both teachers and students to fulfill the increasing demand of the contemporary world. The current paper explores the awareness of, and attitude towards, using ICT in teaching by the Indian teachers in UAE based on their gender and age. The data were…

Perspectives on cervical cancer screening among educated Muslim women in Dubai (the UAE): a qualitative study.

PubMed

Khan, Sarah; Woolhead, Gillian

2015-10-24

Cervical cancer (CC) is the seventh leading cause of death among women in the United Arab Emirates (UAE), with most deaths attributed to late detection of this cancer. The UAE lacks a national CC screening programme. Thus, cervical screening is only performed opportunistically during women's visits to health facilities. CC screening rates in the UAE are as low as 16.9 %, and little is known about the perspectives of the nation's educated Muslim women regarding screening. Consequently, the aim of this study is to explore Muslim women's perspectives towards cervical screening in Dubai to promote strategies for increasing its uptake, thereby leading to a decrease in morbidity and mortality associated with CC. Interpretivist and social constructivist epistemological approaches were applied for this qualitative study. Data were obtained through 13 in-depth interviews. Purposive and snowballing methods were used to recruit six South Asian women and seven Emirati women living in Dubai. Thematic content analysis was concurrently applied with comparative analysis to the data. Four themes regarding women's perceptions of CC emerged from the data. First, CC was considered a 'silent disease' that could be detected with early screening. However, it was also associated with extramarital sexual relations, which negatively influenced screening uptake. Second, women's fear, pain and embarrassment, along with cultural influences, deterred them from undergoing screening. Third, a growing mistrust of allopathic medicine and impersonal healthcare promoted a negative view of screening. Last, women became aware of screening mainly when they were pregnant or receiving fertility treatment. The study highlighted a number of important factors relating to cultural, religious and sexual behaviour that shaped educated Muslim women's perspectives on CC screening. Evidently, the current opportunistic approach to screening is flawed. A national awareness programme on CC screening should be

Accurate critical pressures for structural phase transitions of group IV, III-V, and II-VI compounds from the SCAN density functional

NASA Astrophysics Data System (ADS)

Shahi, Chandra; Sun, Jianwei; Perdew, John P.

2018-03-01

Most of the group IV, III-V, and II-VI compounds crystallize in semiconductor structures under ambient conditions. Upon application of pressure, they undergo structural phase transitions to more closely packed structures, sometimes metallic phases. We have performed density functional calculations using projector augmented wave (PAW) pseudopotentials to determine the transition pressures for these transitions within the local density approximation (LDA), the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA), and the strongly constrained and appropriately normed (SCAN) meta-GGA. LDA underestimates the transition pressure for most of the studied materials. PBE under- or overestimates in many cases. SCAN typically corrects the errors of LDA and PBE for the transition pressure. The accuracy of SCAN is comparable to that of computationally expensive methods like the hybrid functional HSE06, the random phase approximation (RPA), and quantum Monte Carlo (QMC), in cases where calculations with these methods have been reported, but at a more modest computational cost. The improvement from LDA to PBE to SCAN is especially clearcut and dramatic for covalent semiconductor-metal transitions, as for Si and Ge, where it reflects the increasing relative stabilization of the covalent semiconducting phases under increasing functional sophistication.

29 CFR 1926.1126 - Chromium (VI).

Code of Federal Regulations, 2014 CFR

2014-07-01

... activity involving chromium cannot release dusts, fumes, or mists of chromium (VI) in concentrations at or... 29 Labor 8 2014-07-01 2014-07-01 false Chromium (VI). 1926.1126 Section 1926.1126 Labor... Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI) in all forms...

29 CFR 1926.1126 - Chromium (VI).

Code of Federal Regulations, 2012 CFR

2012-07-01

... activity involving chromium cannot release dusts, fumes, or mists of chromium (VI) in concentrations at or... 29 Labor 8 2012-07-01 2012-07-01 false Chromium (VI). 1926.1126 Section 1926.1126 Labor... Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI) in all forms...

29 CFR 1926.1126 - Chromium (VI).

Code of Federal Regulations, 2011 CFR

2011-07-01

... activity involving chromium cannot release dusts, fumes, or mists of chromium (VI) in concentrations at or... 29 Labor 8 2011-07-01 2011-07-01 false Chromium (VI). 1926.1126 Section 1926.1126 Labor... Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI) in all forms...

29 CFR 1926.1126 - Chromium (VI).

Code of Federal Regulations, 2013 CFR

2013-07-01

... activity involving chromium cannot release dusts, fumes, or mists of chromium (VI) in concentrations at or... 29 Labor 8 2013-07-01 2013-07-01 false Chromium (VI). 1926.1126 Section 1926.1126 Labor... Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI) in all forms...

Reduction of toxic Cr(VI)-humic acid in an ionic liquid

NASA Astrophysics Data System (ADS)

Huang, Hsin-Liang; Huang, Hsin-Hung; Wei, Yu Jhe

2017-07-01

Remediation of soil contaminated by toxic hexavalent chromium species associated with humic acid (Cr(VI)-HA) and absorbed Cr(VI) in pores frequently experiences technical difficulties. In the present work, a feasibility study for extraction of the Cr(VI) species from a molecular sieve MCM-41 (Mobil Composition of Matter No. 41) that was used to simulate the pore system of soil, with a green solvent (ionic liquid), 1-butyl-3-methylimidazolium chloride ([C4mim][Cl]), was carried out. After a 30-min extraction, approximately 70% of the Cr(VI) species can be extracted. By component fitted X-ray absorption near edge structure (XANES) spectroscopy, about 48% of the Cr(VI)-HA are reduced to form less toxic species (Cr(III)-HA) during extraction with [C4mim][Cl]. Note that the Cr-O in the [C4mim][Cl] phase has a slightly greater bond distance (BD) (0.162 nm) possibly due to the fact of that the fraction of Cr(III) is increased in the extraction process. The non-extractable chromium remaining in MCM-41 has a much greater fraction of Cr(III) (78%) and its BD is further increased to 0.195 nm. The coordination numbers of chromium for the 1st shell Cr-O in the Cr(VI) and Cr(III) species are in the range of 2.4-2.9, suggesting that chromium is chelated with HA and adsorbed in MCM-41. The 1H NMR data also suggest that the enhanced reduction of the Cr(VI) species may be related to interactions between chromium species and electron-rich imidazole ring of the [C4mim]+. This work also exemplifies that the fate of toxic chromium species in the complicated remediation of contaminated soils can be revealed in a molecule-scale study by synchrotron X-ray absorption spectroscopy.

Nanowire Ice of Phase VI and Distorted VII in Mesoporous Silica Nanotorus Superlattice

NASA Astrophysics Data System (ADS)

Zhu, Jinlong; Zhang, Jianzhong; Zhao, Yusheng

2014-03-01

The motivation of nano H2O realization and characterization is the highly polarized nature of H2O molecules and the spatial hydrogen bonded networks both in liquid and solid form. The hydrogen bonding character of water molecules results in a remarkably rich phase diagram in the pressure-temperature space. Water/Ice confined in nanochannels showed novel structures and properties as results of hydrophobic and hydrophilic interactions and hydrogen bonding interaction between water molecule and the surface of nanochannel. Studies on nano H2O can provide potential pathway to understand the complicated structure evolutions of ice in the P- T space, because the interplay between nano-confinement and strong intermolecular hydrogen interactions can lead to even richer ice structures which were not found in the none-confined bulk form. The high pressure experiment indicated that the pressure of nanowire ice VI and VII shifted up to 1.7 GPa and 2.5 GPa, and about ~ 0.65 GPa and 0.4 GPa higher than that of normal ice. The nano size effect and the strength of mesoporous silica nanotorus are responsible for the pressure shifts of ice phase regions. More pronounced, the cubic ice VII changed into a tetragonal distorted ``psuedocubic'' structure of the nanowire ice when confined in the mesoporous tubes. The degree of tetragonality increased with increasing pressure, which is resulted from the uniaxial pressure nanowire ice felt, and the anisotropic hydrogen bonding interactions including the H2O-H2O hydrogen bonds in the bulk of the ice and the H2O-silica -OH hydrogen bonds between the interface of nanowire ice and mesoporous silica. The experimental work has benefited from the use of CHESS at Cornell University, which is supported by the NSF award DMR-0936384.

Microbial reduction of U(VI) under alkaline conditions: implications for radioactive waste geodisposal.

PubMed

Williamson, Adam J; Morris, Katherine; Law, Gareth T W; Rizoulis, Athanasios; Charnock, John M; Lloyd, Jonathan R

2014-11-18

Although there is consensus that microorganisms significantly influence uranium speciation and mobility in the subsurface under circumneutral conditions, microbiologically mediated U(VI) redox cycling under alkaline conditions relevant to the geological disposal of cementitious intermediate level radioactive waste, remains unexplored. Here, we describe microcosm experiments that investigate the biogeochemical fate of U(VI) at pH 10-10.5, using sediments from a legacy lime working site, stimulated with an added electron donor, and incubated in the presence and absence of added Fe(III) as ferrihydrite. In systems without added Fe(III), partial U(VI) reduction occurred, forming a U(IV)-bearing non-uraninite phase which underwent reoxidation in the presence of air (O2) and to some extent nitrate. By contrast, in the presence of added Fe(III), U(VI) was first removed from solution by sorption to the Fe(III) mineral, followed by bioreduction and (bio)magnetite formation coupled to formation of a complex U(IV)-bearing phase with uraninite present, which also underwent air (O2) and partial nitrate reoxidation. 16S rRNA gene pyrosequencing showed that Gram-positive bacteria affiliated with the Firmicutes and Bacteroidetes dominated in the post-reduction sediments. These data provide the first insights into uranium biogeochemistry at high pH and have significant implications for the long-term fate of uranium in geological disposal in both engineered barrier systems and the alkaline, chemically disturbed geosphere.

Deep crustal structure of the UAE-Oman mountain belt from seismic and gravity data

NASA Astrophysics Data System (ADS)

Pilia, S.; Tanveer, M.; Ali, M.; Watts, A. B.; Searle, M. P.; Keats, B. S.

2016-12-01

The UAE-Oman mountains constitute a 700 km long, 50 km wide compressional orogenic belt that developed during the Cenozoic on an underlying extensional Tethyan rifted margin. It contains the world's largest and best-exposed thrust sheet of oceanic crust and upper mantle (Semail Ophiolite), which was obducted onto the Arabian rifted continental margin during the Late Cretaceous. Although the shallow structure of the UAE-Oman mountain belt is reasonably well known through the exploitation of a diverse range of techniques, information on deeper structure remains little. Moreover, the mechanisms by which dense oceanic crustal and mantle rocks are emplaced onto less dense and more buoyant continental crust are still controversial and remain poorly understood. The focus here is on an active-source seismic and gravity E-W transect extending from the UAE-mountain belt to the offshore. Seismic refraction data were acquired using the survey ship M/V Hawk Explorer, which was equipped with a large-volume airgun array (116 liters). About 400 air gun shots at 50-second time interval were recorded on land by eight broadband seismometers. In addition, reflection data were acquired at 20 seconds interval and recorded by a 5-km-long multichannel streamer. Results presented here include an approximately 85 km long (stretching about 35 km onshore and 50 km offshore) P-wave velocity crustal profile derived by a combination of forward modelling and inversion of both diving and reflected wave traveltimes using RAYINVR software. We employ a new robust algorithm based on a Monte Carlo approach (VMONTECARLO) to address the velocity model uncertainties. We find ophiolite seismic velocities of about 5.5 km/s, underlain by a thin layer of slower material (about 4.5 km/s). Furthermore, the velocity model reveals a Moho depth that rises from ca 30 km in the west to ca 20 km in the east. A poststack depth-migrated profile (about 50 km long) coincident with the offshore part of the refraction

Electromagnetic mapping of buried paleochannels in eastern Abu Dhabi Emirate, U.A.E.

USGS Publications Warehouse

Fitterman, D.V.; Menges, C.M.; Al Kamali, A.M.; Essa, Jama F.

1991-01-01

Transient electromagnetic soundings and terrain conductivity meter measurements were used to map paleochannel geometry in the Al Jaww Plain of eastern Abu Dhabi Emirate, U.A.E. as part of an integrated hydrogeologic study of the Quaternary alluvial aquifer system. Initial interpretation of the data without benefit of well log information was able to map the depth to a conductive clay layer of Tertiary age that forms the base of the aquifer. Comparison of the results with induction logs reveals that a resistive zone exists that was incorporated into the interpretation and its lateral extent mapped with the transient electromagnetic sounding data. ?? 1991.

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

NASA Astrophysics Data System (ADS)

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

Controls on rheology of peridotite at a palaeosubduction interface: a transect across the base of the Oman-UAE ophiolite

NASA Astrophysics Data System (ADS)

Ambrose, T. K.; Wallis, D.; Hansen, L. N.; Waters, D. J.; Searle, M. P.

2017-12-01

Studies of experimentally deformed rocks and small-scale natural shear zones have demonstrated that volumetrically minor phases can control strain localisation by limiting grain growth and promoting grain-size sensitive deformation mechanisms. Such studies are often used to infer a critical role for minor phases in the development of plate boundaries. However, the role of of minor phases in strain localisation at plate boundaries remains to be tested by direct observation. To test the hypothesis that minor phases control strain localisation at plate boundaries, we conducted microstructural analyses of peridotite samples collected across the base of the Oman-UAE ophiolite. The base of the ophiolite is marked by the Semail thrust, which represents the now exhumed contact between subducted oceanic crust and the overlying mantle wedge. As such, the base of the ophiolite provides the opportunity to directly examine a former plate boundary. Our results demonstrate that the mean olivine grain size is inversely proportional to the abundance of minor phases (primarily pyroxene), consistent with suppression of grain growth by grain-boundary pinning. Our results also reveal that mean olivine grain size is proportional to CPO strength, suggesting that the fraction of strain accommodated by different deformation mechanisms varied spatially. Experimentally-derived flow laws indicate that under the inferred deformation conditions the viscosity of olivine was grain-size sensitive. As such, grain size, and thereby the abundance of minor phases, influenced viscosity during subduction-related deformation along the base of the mantle wedge. We calculate that viscosity and strain rate respectively decrease and increase by approximately an order of magnitude towards the base of the ophiolite. Our data indicate that this rheological weakening was primarily the result of more abundant secondary phases near the base of the ophiolite. Our interpretations are consistent with those of

Optical determination of crystal phase in semiconductor nanocrystals

PubMed Central

Lim, Sung Jun; Schleife, André; Smith, Andrew M.

2017-01-01

Optical, electronic and structural properties of nanocrystals fundamentally derive from crystal phase. This is especially important for polymorphic II–VI, III–V and I-III-VI2 semiconductor materials such as cadmium selenide, which exist as two stable phases, cubic and hexagonal, each with distinct properties. However, standard crystallographic characterization through diffraction yields ambiguous phase signatures when nanocrystals are small or polytypic. Moreover, diffraction methods are low-throughput, incompatible with solution samples and require large sample quantities. Here we report the identification of unambiguous optical signatures of cubic and hexagonal phases in II–VI nanocrystals using absorption spectroscopy and first-principles electronic-structure theory. High-energy spectral features allow rapid identification of phase, even in small nanocrystals (∼2 nm), and may help predict polytypic nanocrystals from differential phase contributions. These theoretical and experimental insights provide simple and accurate optical crystallographic analysis for liquid-dispersed nanomaterials, to improve the precision of nanocrystal engineering and improve our understanding of nanocrystal reactions. PMID:28513577

Extraction and separation of tungsten (VI) from aqueous media with Triton X-100-ammonium sulfate-water aqueous two-phase system without any extractant.

PubMed

Yongqiang Zhang; Tichang Sun; Tieqiang Lu; Chunhuan Yan

2016-11-25

An aqueous two-phase system composed of Triton X-100-(NH 4 ) 2 SO 4 -H 2 O was proposed for extraction and separation of tungsten(VI) from aqueous solution without using any extractant. The effects of aqueous pH, concentration of ammonium sulfate, Triton X-100 and tungsten, extracting temperature on the extraction of tungsten were investigated. The extraction of tungsten has remarkable relationship with aqueous pH and are to above 90% at pH=1.0-3.0 under studied pH range (pH=1.0-7.0) and increases gradually with increasing Triton X-100 concentration, but decreases slightly with increasing ammonium sulfate concentration. The extraction percentage of tungsten is hardly relevant to temperature but its distribution coefficient linearly increases with increasing temperature within 303.15-343.15K. The distribution coefficient of tungsten increases with the increase of initial tungsten concentration (0.1-3%) and temperature (303.15 K-333.15K). The solubilization capacity of tungsten in Triton X-100 micellar phase is independent of temperature. FT-IR analysis reveals that there is no evident interaction between polytungstate anion and ether oxygen unit in Triton X-100, and DLS analysis indicates that zeta potential of Triton X-100 micellar phase have a little change from positive to negative after extracting tungsten. Based on the above-mentioned results, it can be deduced that polytungstate anions are solubilized in hydrophilic outer shell of Triton X-100 micelles by electrostatic attraction depending on its relatively high hydrophobic nature. The stripping of tungsten is mainly influenced by temperature and can be easily achieved to 95% in single stage stripping. The tungsten (VI) is separated out from solution containing Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Al(III), Cr(III) and Mn(II) under the suitable conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Sero-efficacy of Vi-polysaccharide tetanus-toxoid typhoid conjugate vaccine (Typbar-TCV).

PubMed

Voysey, Merryn; Pollard, Andrew J

2018-01-17

Salmonella Typhi is the major cause of enteric fever in lower income countries. New conjugate vaccines show promise as public health interventions, however there are no efficacy data available from endemic areas. Data were obtained from a previously published phase 3 randomised controlled trial comparing Vi-polysaccharide tetanus-toxoid conjugate vaccine (Typbar-TCV; Bharat Biotech Intl Ltd, India): (Vi-TT) with Vi-polysaccharide (Typbar; Bharat Biotech Intl Ltd, India): (Vi-PS) in participants aged 2- 45 years. An additional open-label arm administered Vi-TT to children aged 6 months to 23 months. The proportion of participants with presumed clinical or subclinical infection ('seroincidence'), was determined using mixture models and compared using relative risks. 81/387 (21%) participants were classified as having presumed typhoid infection during the 2 year period post-vaccination. Seroincidence was lower in those randomised to Vi-TT than Vi-PS in those aged 2-45 years; 21/155 (13.5%) vs 47/129 (36.4%); RR 0.372 (95%CI 0.235-0.588), p<0.0001 and in those aged 2-15 years RR 0.424 (95%CI 0.231-0.778), p=0.0039. There was no difference in seroincidence in those receiving Vi-TT aged 2-45 years and those aged 6-23 months; 21/155 (13.5%) vs 13/103 (12.6%); RR 1.073 (0.563, 2.046), p=0.8293. Vaccine seroefficacy was 85% (95%CI 80-88%). This is the first field estimate of the seroefficacy of a Vi-TT vaccine and shows that Typbar TCV substantially reduces the number of serologically defined (sub)clinical infections in infants, children and adults. These results support the recent World Health Organisation recommendations for deployment of typhoid conjugate vaccines in high burden areas. © The Author(s) 2018. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Fate and transport of uranium (VI) in weathered saprolite

DOE PAGES

Kim, Young-Jin; Brooks, Scott C.; Zhang, Fan; ...

2014-11-09

We conducted batch and column experiments to investigate sorption and transport of uranium (U) in the presence of saprolite derived from interbedded shale, limestone, and sandstone sequences. Sorption kinetics were measured at two initial concentrations (C0; 1, 10 mM) and three soil:solution ratios (Rs/w; 0.005, 0.25, 2 kg/L) at pH 4.5 (pH of the saprolite). The rate of U loss from solution (mmole/L/h) increased with increasing Rs/w. Uranium sorption exhibited a fast phase with 80% sorption in the first eight hours for all C0 and Rs/w values and a slow phase during which the reaction slowly approached (pseudo) equilibrium overmore » the next seven days. The pH-dependency of U sorption was apparent in pH sorption edges. U(VI) sorption increased over the pH range 4e6, then decreased sharply at pH > 7.5. U(VI) sorption edges were well described by a surface complexation model using calibrated parameters and the reaction network proposed by Waite et al. (1994). Sorption isotherms measured using the same Rs/w and pH values showed a solids concentration effect where U(VI) sorption capacity and affinity decreased with increasing solids concentration. Moreover, this effect may have been due to either particle aggregation or competition between U(VI) and exchangeable cations for sorption sites. The surface complexation model with calibrated parameters was able to predict the general sorption behavior relatively well, but failed to reproduce solid concentration effects, implying the importance of appropriate design if batch experiments are to be utilized for dynamic systems. Transport of U(VI) through the packed column was significantly retarded. We also conducted transport simulations using the reactive transport model HydroGeoChem (HGC) v5.0 that incorporated the surface complexation reaction network used to model the batch data. Model parameters reported by Waite et al. (1994) provided a better prediction of U transport than optimized parameters derived from our

The effect of calcium on aqueous uranium(VI) speciation and adsorption to ferrihydrite and quartz

USGS Publications Warehouse

Fox, P.M.; Davis, J.A.; Zachara, J.M.

2006-01-01

Recent studies of uranium(VI) geochemistry have focused on the potentially important role of the aqueous species, CaUO2 (CO3)32- and Ca2 UO2(CO3)30(aq), on inhibition of microbial reduction and uranium(VI) aqueous speciation in contaminated groundwater. However, to our knowledge, there have been no direct studies of the effects of these species on U(VI) adsorption by mineral phases. The sorption of U(VI) on quartz and ferrihydrite was investigated in NaNO3 solutions equilibrated with either ambient air (430 ppm CO2) or 2% CO2 in the presence of 0, 1.8, or 8.9 mM Ca2+. Under conditions where the Ca2UO2(CO3)30 (aq) species predominates U(VI) aqueous speciation, the presence of Ca in solution lowered U(VI) adsorption on quartz from 77% in the absence of Ca to 42% and 10% at Ca concentrations of 1.8 and 8.9 mM, respectively. U(VI) adsorption to ferrihydrite decreased from 83% in the absence of Ca to 57% in the presence of 1.8 mM Ca. Surface complexation model predictions that included the formation constant for aqueous Ca2UO2(CO3)30(aq) accurately simulated the effect of Ca2+ on U(VI) sorption onto quartz and ferrihydrite within the thermodynamic uncertainty of the stability constant value. This study confirms that Ca2+ can have a significant impact on the aqueous speciation of U(VI), and consequently, on the sorption and mobility of U(VI) in aquifers. ?? 2005 Elsevier Inc. All rights reserved.

FANCD2 monoubiquitination and activation by hexavalent chromium [Cr(VI)] exposure

PubMed Central

Vilcheck, Susan K.; Ceryak, Susan; O’Brien, Travis J.; Patierno, Steven R.

2007-01-01

Fanconi anemia (FA) is a rare autosomal recessive disorder characterized by congenital abnormalities, progressive bone marrow failure, and cancer susceptibility. FA cells are hypersensitive to DNA crosslinking agents. FA is a genetically heterogeneous disease with at least 11 complementation groups. The eight cloned FA proteins interact in a common pathway with established DNA-damage-response proteins, including BRCA1 and ATM. Six FA proteins (A, C, E, F, G, and L) regulate the monoubiquitination of FANCD2 after DNA damage by crosslinking agents, which targets FANCD2 to BRCA1 nuclear foci containing BRCA2 (FANCD1) and RAD51. Some forms of hexavalent chromium [Cr(VI)] are implicated as respiratory carcinogens and induce several types of DNA lesions, including DNA interstrand crosslinks. We have shown that FA-A fibroblasts are hypersensitive to both Cr(VI)-induced apoptosis and clonogenic lethality. Here we show that Cr(VI) treatment induced monoubiquitination of FANCD2 in normal human fibroblasts, providing the first molecular evidence of Cr(VI)-induced activation of the FA pathway. FA-A fibroblasts demonstrated no FANCD2 monoubiquitination, in keeping with the requirement of FA-A for this modification. We also found that Cr(VI) treatment induced significantly more S-phase-dependent DNA double strand breaks (DSBs), as measured by γ-H2AX expression, in FA-A fibroblasts compared to normal cells. However, and notably, DSBs were repaired equally in both normal and FA-A fibroblasts during recovery from Cr(VI) treatment. While previous research on FA has defined the genetic causes of this disease, it is critical in terms of individual risk assessment to address how cells from FA patients respond to genotoxic insult. PMID:16893675

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schreck, S.; Sant, T.; Micallef, D.

Wind turbine structures and components suffer excessive loads and premature failures when key aerodynamic phenomena are not well characterized, fail to be understood, or are inaccurately predicted. Turbine blade rotational augmentation remains incompletely characterized and understood, thus limiting robust prediction for design. Pertinent rotational augmentation research including experimental, theoretical, and computational work has been pursued for some time, but large scale wind tunnel testing is a relatively recent development for investigating wind turbine blade aerodynamics. Because of their large scale and complementary nature, the MEXICO and UAE Phase VI wind tunnel experiments offer unprecedented synergies to better characterize and understandmore » rotational augmentation of blade aerodynamics.« less

The Effect of Student Teaching Experience on Preservice Elementary Teachers' Self-Efficacy Beliefs for Technology Integration in the UAE

ERIC Educational Resources Information Center

Al-Awidi, Hamed Mubarak; Alghazo, Iman Mohammad

2012-01-01

This study examines the effect of the student teaching experience on preservice elementary teachers' self-efficacy beliefs and the sources of their beliefs about technology integration in teaching in the UAE. The participants were 62 pre-service elementary teachers at the United Arab Emirates University. Pre- and post-survey was administered to…

In situ Bioreduction of Uranium (VI) in Groundwater and Sediments with Edible Oil as the Electron Donor

NASA Astrophysics Data System (ADS)

Wu, W.; Watson, D. B.; Mehlhorn, T.; Zhang, G.; Earles, J.; Lowe, K.; Phillips, J.; Boyanov, M.; Kemner, K. M.; Schadt, C. W.; Brooks, S. C.; Criddle, C.; Jardine, P.

2009-12-01

In situ bioremediation of a uranium-contaminated aquifer was conducted at the US DOE Environmental Remediation Sciences Program (ERSP) Integrated Field Research Challenge (IFRC) site, in Oak Ridge, TN. Edible oil was tested as a slow-release electron donor for microbially mediated U (VI) reduction. Uranium contaminated sediments from the site were used in laboratory microcosm tests to study the feasibility of using this electron donor under anaerobic, ambient temperature conditions. Parallel microcosms were established using ethanol as electron donor for comparison. The tests also examined the impact of sulfate concentrations on U (VI) reduction. The oil was degraded by indigenous microorganisms with acetate as a major product but at a much slower rate than ethanol. The rapid removal of U (VI) from the aqueous phase occurred concurrently with acetate production and sulfate reduction. Initial U(VI) concentration in the aqueous phase increased with increased sulfate concentration (1 vs. 5 mM), likely due to U(VI) desorption from the solid phase, but more U(VI) was reduced with higher initial sulfate level. Finally, the bioreaction in microcosms progressed to methanogenesis. Subsequently, a field test with the edible oil was conducted in a highly permeable gravelly layer (hydraulic conductivity 0.076 cm/sec). Groundwater at the site contained 5-6 μM U; 1.0-1.2 mM sulfate; 3-4 mM Ca; pH 6.8. Diluted emulsified oil (20% solution) was injected into three injection wells within 2 hrs. Geochemical analysis of site groundwater demonstrated the sequential reduction of nitrate, Mn, Fe(III) and sulfate. Transient accumulation of acetate was observed as an intermediate in the oil degradation. Reduction and removal of uranium from groundwater was observed in all wells connected to the injection wells after 2-4 weeks. Uranium concentrations in groundwater were reduced to below 0.126 μM (EPA drinking water standard), at some well locations. Rebound of U in groundwater was

Safety, immunogenicity and dose ranging of a new Vi-CRM₁₉₇ conjugate vaccine against typhoid fever: randomized clinical testing in healthy adults.

PubMed

van Damme, Pierre; Kafeja, Froukje; Anemona, Alessandra; Basile, Venere; Hilbert, Anne Katrin; De Coster, Ilse; Rondini, Simona; Micoli, Francesca; Qasim Khan, Rana M; Marchetti, Elisa; Di Cioccio, Vito; Saul, Allan; Martin, Laura B; Podda, Audino

2011-01-01

Typhoid fever causes more than 21 million cases of disease and 200,000 deaths yearly worldwide, with more than 90% of the disease burden being reported from Asia. Epidemiological data show high disease incidence in young children and suggest that immunization programs should target children below two years of age: this is not possible with available vaccines. The Novartis Vaccines Institute for Global Health developed a conjugate vaccine (Vi-CRM₁₉₇) for infant vaccination concomitantly with EPI vaccines, either starting at 6 weeks with DTP or at 9 months with measles vaccine. We report the results from a Phase 1 and a Phase 2 dose ranging trial with Vi-CRM₁₉₇ in European adults. Following randomized blinded comparison of single vaccination with either Vi-CRM₁₉₇ or licensed polysaccharide vaccines (both containing 25·0 µg of Vi antigen), a randomised observer blinded dose ranging trial was performed in the same center to compare three concentrations of Vi-CRM₁₉₇ (1·25 µg, 5·0 µg and 12·5 µg of Vi antigen) with the polysaccharide vaccine. All vaccines were well tolerated. Compared to the polysaccharide vaccine, Vi-CRM₁₉₇ induced a higher incidence of mild to moderate short lasting local pain. All Vi-CRM₁₉₇ formulations induced higher Vi antibody levels compared to licensed control, with clear dose response relationship. Vi-CRM₁₉₇ did not elicit safety concerns, was highly immunogenic and is therefore suitable for further clinical testing in endemic populations of South Asia. ClinicalTrials.gov NCT01123941 NCT01193907.

Ferrate(VI) oxidation of zinc-cyanide complex.

PubMed

Yngard, Ria; Damrongsiri, Seelawut; Osathaphan, Khemarath; Sharma, Virender K

2007-10-01

Zinc-cyanide complexes are found in gold mining effluents and in metal finishing rinse water. The effect of Zn(II) on the oxidation of cyanide by ferrate(VI) (Fe(VI)O(4)(2-), Fe(VI)) was thus investigated by studying the kinetics of the reaction of Fe(VI) with cyanide present in a potassium salt of a zinc cyanide complex (K(2)Zn(CN)(4)) and in a mixture of Zn(II) and cyanide solutions as a function of pH (9.0-11.0). The rate-law for the oxidation of Zn(CN)(4)(2-) by Fe(VI) was found to be -d[Fe(VI)]/dt=k[Fe(VI)][Zn(CN)(4)(2-)](0.5). The rate constant, k, decreased with an increase in pH. The effect of temperature (15-45 degrees C) on the oxidation was studied at pH 9.0, which gave an activation energy of 45.7+/-1.5kJmol(-1). The cyanide oxidation rate decreased in the presence of the Zn(II) ions. However, Zn(II) ions had no effect on the cyanide removal efficiency by Fe(VI) and the stoichiometry of Fe(VI) to cyanide was approximately 1:1; similar to the stoichiometry in absence of Zn(II) ions. The destruction of cyanide by Fe(VI) resulted in cyanate. The experiments on removal of cyanide from rinse water using Fe(VI) demonstrated complete conversion of cyanide to cyanate.

76 FR 60593 - Title VI; Proposed Circular

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-29

... DEPARTMENT OF TRANSPORTATION Federal Transit Administration [Docket No. FTA-2011-0054] Title VI... complying with Title VI of the Civil Rights Act of 1964. The purpose of this Circular is to provide.... Department of Transportation's Title VI regulations (49 CFR part 21). FTA is updating its Title VI Circular...

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

PubMed

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.

29 CFR 1915.1026 - Chromium (VI).

Code of Federal Regulations, 2012 CFR

2012-07-01

... a specific process, operation, or activity involving chromium cannot release dusts, fumes, or mists... 29 Labor 7 2012-07-01 2012-07-01 false Chromium (VI). 1915.1026 Section 1915.1026 Labor... § 1915.1026 Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI...

29 CFR 1915.1026 - Chromium (VI).

Code of Federal Regulations, 2011 CFR

2011-07-01

... a specific process, operation, or activity involving chromium cannot release dusts, fumes, or mists... 29 Labor 7 2011-07-01 2011-07-01 false Chromium (VI). 1915.1026 Section 1915.1026 Labor... § 1915.1026 Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI...

29 CFR 1915.1026 - Chromium (VI).

Code of Federal Regulations, 2013 CFR

2013-07-01

... a specific process, operation, or activity involving chromium cannot release dusts, fumes, or mists... 29 Labor 7 2013-07-01 2013-07-01 false Chromium (VI). 1915.1026 Section 1915.1026 Labor... § 1915.1026 Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI...

29 CFR 1915.1026 - Chromium (VI).

Code of Federal Regulations, 2014 CFR

2014-07-01

... a specific process, operation, or activity involving chromium cannot release dusts, fumes, or mists... 29 Labor 7 2014-07-01 2014-07-01 false Chromium (VI). 1915.1026 Section 1915.1026 Labor... § 1915.1026 Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI...

Monolayer II-VI semiconductors: A first-principles prediction

NASA Astrophysics Data System (ADS)

Zheng, Hui; Chen, Nian-Ke; Zhang, S. B.; Li, Xian-Bin

A systematic study of 32 honeycomb monolayer II-VI semiconductors is carried out by first-principles methods. It appears that BeO, MgO, CaO, ZnO, CdO, CaS, SrS, SrSe, BaTe, and HgTe honeycomb monolayers have a good dynamic stability which is revealed by phonon calculations. In addition, from the molecular dynamic (MD) simulation of other unstable candidates, we also find two extra monolayers dynamically stable, which are tetragonal BaS and orthorhombic HgS. The honeycomb monolayers exist in form of either a planar perfect honeycomb or a low-buckled 2D layer, all of which possess a band gap and most of them are in the ultraviolet region. Interestingly, the dynamically stable SrSe has a gap near visible light, and displays exotic electronic properties with a flat top of the valence band, and hence has a strong spin polarization upon hole doping. The honeycomb HgTe has been reported to achieve a topological nontrivial phase under appropriate in-plane tensile strain and spin-orbital coupling (SOC). Some II-VI partners with less than 5% lattice mismatch may be used to design novel 2D heterojunction devices. If synthesized, potential applications of these 2D II-VI families could include optoelectronics, spintronics, and strong correlated electronics. Distinguished Student (DS) Program of APS FIP travel funds.

The Ecology of Al-Samaliah Island, U.A.E.

NASA Astrophysics Data System (ADS)

Zahran, M. A.; Al-Ansari, F. M.

1999-08-01

Al-Samaliah Island is one of the inshore islands of U.A.E. located at about 12 km north-east of Abu Dhabi in the Arabian Gulf. It has a flat undulating surface with neither sand dunes nor rocky hills. Its sandy soil is generally salt-affected with variable percentages of salts. The vegetation of Al-Samaliah Island is essentially halophytic and may be categorized as: seagrasses, mangal and littoral saltmarsh types. The main species include: Cymodocea ciliata, Halophila spp. and Halodula univervis (seagrasses), some algae, Avicennia marina (mangrove), Arthrocnemum macrostachyum, Seidlitzia rosmarinus, and Suaeda vermiculata (salt marsh). Other halophytes commonly present are: Anabasis setifera, Halocnemum strobilaeum, Halopeplis perfoliata, Salsola imbricata and Zygophyllum gatarense in addition to two annuals: Schangenia aegyptiaca and Zygophyllum simplex. Phoenix dactylifera is cultivated in local areas covered with sandy sheets. Between the date palm trees there is a thin growth of Cyperus conglomeratus. Some plant species have been analysed chemically to determine their main constituents. The relationships between the environmental factors and the plant life of the islands are discussed.

29 CFR 1926.1126 - Chromium (VI).

Code of Federal Regulations, 2010 CFR

2010-07-01

... is present or is likely to be present from skin or eye contact with chromium (VI), the employer shall... cleaned in a manner that minimizes skin or eye contact with chromium (VI) and effectively prevents the... CFR 1926.51 Where skin contact with chromium (VI) occurs, the employer shall provide washing...

Measurement of greenhouse gases in UAE by using Unmanned Aerial Vehicle (UAV)

NASA Astrophysics Data System (ADS)

Abou-Elnour, Ali; Odeh, Mohamed; Abdelrhman, Mohammed; Balkis, Ahmed; Amira, Abdelraouf

2017-04-01

In the present work, a reliable and low cost system has been designed and implemented to measure greenhouse gases (GHG) in United Arab Emirates (UAE) by using unmanned aerial vehicle (UAV). A set of accurate gas, temperature, pressure, humidity sensors are integrated together with a wireless communication system on a microcontroller based platform to continuously measure the required data. The system instantaneously sends the measured data to a center monitoring unit via the wireless communication system. In addition, the proposed system has the features that all measurements are recorded directly in a storage device to allow effective monitoring in regions with weak or no wireless coverage. The obtained data will be used in all further sophisticated calculations for environmental research and monitoring purposes.

Reduction of Cr(VI) under acidic conditions by the facultative Fe(III)-reducing bacterium Acidiphilium cryptum

DOE Office of Scientific and Technical Information (OSTI.GOV)

David E. Cummings; Scott Fendorf; Rajesh K. Sani

2007-01-01

The potential for biological reduction of Cr(VI) under acidic conditions was evaluated with the acidophilic, facultatively metal-reducing bacterium Acidiphilium cryptum strain JF-5 to explore the role of acidophilic microorganisms in the Cr cycle in low-pH environments. An anaerobic suspension of washed A. cryptum cells rapidly reduced 50 M Cr(VI) at pH 3.2; biological reduction was detected from pH 1.7-4.7. The reduction product, confirmed by XANES analysis, was entirely Cr(III) that was associated predominantly with the cell biomass (70-80%) with the residual residing in the aqueous phase. Reduction of Cr(VI) showed a pH optimum similar to that for growth and wasmore » inhibited by 5 mM HgCl2, suggesting that the reaction was enzyme-mediated. Introduction of O2 into the reaction medium slowed the reduction rate only slightly, whereas soluble Fe(III) (as ferric sulfate) increased the rate dramatically, presumably by the shuttling of electrons from bioreduced Fe(II) to Cr(VI) in a coupled biotic-abiotic cycle. Starved cells could not reduce Cr(VI) when provided as sole electron acceptor, indicating that Cr(VI) reduction is not an energy-conserving process in A. cryptum. We speculate, rather, that Cr(VI) reduction is used here as a detoxification mechanism.« less

Development of the Preverbal Visual Assessment (PreViAs) questionnaire.

PubMed

Pueyo, Victoria; García-Ormaechea, Inés; González, Inmaculada; Ferrer, Concepción; de la Mata, Guillermo; Duplá, María; Orós, Pedro; Andres, Eva

2014-04-01

Visual cognitive functions of preverbal infants are evaluated by means of a behavioral assessment. Parents or primary caregivers may be appropriate to certify the acquisition of certain abilities. To develop the PreViAs (Preverbal Visual Assessment) questionnaire to assess visual behavior of infants under 24 months of age and to assess the normative outcomes for each item at each age. The process was divided into three phases: scale development (items and domains generation), pilot testing, and exploratory analysis. The final version of the PreViAs questionnaire consisted of 30 items, each related to one or more of four domains (visual attention, visual communication, visual-motor coordination, and visual processing). For the exploratory analysis, 298 children (159 boys and 139 girls) were recruited. Their ages ranged from 0.1 to 24 months (mean, 11.2 months). Internal consistency of the questionnaire was high for all domains (Cronbach's α coefficients of 0.85-0.94). The PreViAs questionnaire is a useful scale for assessing visual cognitive abilities of infants under 24 months of age. It is easy and feasible to complete by primary caregivers. Copyright © 2014 Elsevier Ltd. All rights reserved.

Formation of stable uranium(VI) colloidal nanoparticles in conditions relevant to radioactive waste disposal.

PubMed

Bots, Pieter; Morris, Katherine; Hibberd, Rosemary; Law, Gareth T W; Mosselmans, J Frederick W; Brown, Andy P; Doutch, James; Smith, Andrew J; Shaw, Samuel

2014-12-09

The favored pathway for disposal of higher activity radioactive wastes is via deep geological disposal. Many geological disposal facility designs include cement in their engineering design. Over the long term, interaction of groundwater with the cement and waste will form a plume of a hyperalkaline leachate (pH 10-13), and the behavior of radionuclides needs to be constrained under these extreme conditions to minimize the environmental hazard from the wastes. For uranium, a key component of many radioactive wastes, thermodynamic modeling predicts that, at high pH, U(VI) solubility will be very low (nM or lower) and controlled by equilibrium with solid phase alkali and alkaline-earth uranates. However, the formation of U(VI) colloids could potentially enhance the mobility of U(VI) under these conditions, and characterizing the potential for formation and medium-term stability of U(VI) colloids is important in underpinning our understanding of U behavior in waste disposal. Reflecting this, we applied conventional geochemical and microscopy techniques combined with synchrotron based in situ and ex situ X-ray techniques (small-angle X-ray scattering and X-ray adsorption spectroscopy (XAS)) to characterize colloidal U(VI) nanoparticles in a synthetic cement leachate (pH > 13) containing 4.2-252 μM U(VI). The results show that in cement leachates with 42 μM U(VI), colloids formed within hours and remained stable for several years. The colloids consisted of 1.5-1.8 nm nanoparticles with a proportion forming 20-60 nm aggregates. Using XAS and electron microscopy, we were able to determine that the colloidal nanoparticles had a clarkeite (sodium-uranate)-type crystallographic structure. The presented results have clear and hitherto unrecognized implications for the mobility of U(VI) in cementitious environments, in particular those associated with the geological disposal of nuclear waste.

Cr(VI) removal on visible light active TiO2 nanotube arrays

NASA Astrophysics Data System (ADS)

Bashirom, Nurulhuda; Zulkifli, Muhammad Afiq; Subagja, Subagja; Kian, Tan Wai; Matsuda, Atsunori; Lockman, Zainovia

2018-05-01

Self-organized TiO2 nanotube (TNT) arrays were fabricated by anodic oxidation of titanium foil in three different fluoride electrolytes: ethylene glycol (EG), glycerol, and sodium sulfate (Na2SO4) at different voltage and anodization time. In these electrolytes, the TNTs were produced in ˜ 2 µm long, but at the different diameter. The size of inner diameter can be arranged from the largest to the smallest value in the order of glycerol > EG > Na2SO4. Crystallization of the TNTs by annealing was led to the formation of anatase-TiO2. The sample can be activated under natural sunlight for reduction of hexavalent chromium, Cr(VI) into trivalent chromium, Cr(III). The reduction was thought to occur via synergistic reactions between adsorption and photoreduction. The result demonstrates 100 % of Cr(VI) removal efficiency over the TNTs grown in EG after 120 min. Whereas, only 48 % and 45 % of Cr(VI) can be removed over the TNTs fabricated in glycerol and Na2SO4, respectively. High photocatalytic activity of the TNTs-EG can be attributed to high crystallinity of anatase phase, enhanced Cr(VI) adsorption, and less electron-hole recombination due to smoother tube walls.

Simultaneous determination of Cr(iii) and Cr(vi) using reversed-phased ion-pairing liquid chromatography with dynamic reaction cell inductively coupled plasma mass spectrometry

USGS Publications Warehouse

Wolf, R.E.; Morrison, J.M.; Goldhaber, M.B.

2007-01-01

A method for the simultaneous determination of Cr(iii) and Cr(vi) species in waters, soil leachates and synthetic bio-fluids is described. The method uses reversed-phase ion-pairing liquid chromatography to separate the chromium species and a dynamic reaction cell (DRC??) equipped ICP-MS for detection of chromium. Separation of the chromium species is carried out in less than 2 min. Cr(iii) is complexed with ethylenediaminetetraacetic acid (EDTA) prior to separation by mixing samples with the mobile phase containing 2.0 mM tetrabutylammonium hydroxide (TBAOH), 0.5 mM EDTA (dipotassium salt), and 5% (vol/vol) methanol, adjusted to pH 7.6. The interfering 40Ar 12C+ background peak at mass 52 was reduced by over four orders of magnitude to less than 200 cps by using 0.65 mL min-1 ammonia as a reaction gas and an RPq setting on the DRC of 0.75. Method detection limits (MDLs) of 0.09 ??g L-1 for Cr(iii) and 0.06 ??g L-1 for Cr(vi) were obtained based on peak areas at mass 52 for 50 ??L injections of low level spikes. Reproducibility at 2 ??g L-1 was 3% RSD for 5 replicate injections. The tolerance of the method to various levels of common cations and anions found in natural waters and to matrix constituents found in soil leachates and simulated gastric and lung fluids was tested by performing spike recovery calculations for a variety of samples. ?? The Royal Society of Chemistry.

Chromium(VI) Removal from Aqueous Solution by Magnetite Coated by a Polymeric Ionic Liquid-Based Adsorbent

PubMed Central

Ferreira, Thania Alexandra; Rodriguez, Jose Antonio; Paez-Hernandez, María Elena; Guevara-Lara, Alfredo; Barrado, Enrique; Hernandez, Prisciliano

2017-01-01

An evaluation of the chromium(VI) adsorption capacity of four magnetite sorbents coated with a polymer phase containing polymethacrylic acid or polyallyl-3-methylimidazolium is presented. Factors that influence the chromium(VI) removal such as solution pH and contact time were investigated in batch experiments and in stirred tank reactor mode. Affinity and rate constants increased with the molar ratio of the imidazolium. The highest adsorption was obtained at pH 2.0 due to the contribution of electrostatic interactions. PMID:28772865

Rare-earth element fractionation in uranium ore and its U(VI) alteration minerals

DOE PAGES

Balboni, Enrica; Spano, T; Cook, N; ...

2017-10-20

We developed a cation exchange chromatography method employing sulfonated polysterene cation resin (DOWEX AG50-X8) in order to separate rare-earth elements (REEs) from uranium-rich materials. The chemical separation scheme is designed to reduce matrix effects and consequently yield enhanced ionization efficiencies for concentration determinations of REEs without significant fractionation using solution mode-inductively coupled plasma mass spectrometry (ICP-MS) analysis. This method was then applied to determine REE abundances in four uraninite (ideally UO 2) samples and their associated U(VI) alteration minerals. In three of the samples analyzed, the concentration of REEs for primary uraninite are higher than those for their corresponding secondarymore » uranium alteration phases. The results for U(VI) alteration minerals of two samples indicate enrichment of the light REEs (LREEs) over the heavy REEs (HREEs). This differential mobilization is attributed to differences in the mineralogical composition of the U(VI) alteration. There is a lack of fractionation of the LREEs in the uraninite alteration rind that is composed of U(VI) minerals containing Ca 2+ as the interlayer cation (uranophane and bequerelite); contrarily, U(VI) alteration minerals containing K + and Pb 2+ as interlayer cations (fourmarierite, dumontite) indicate fractionation (enrichment) of the LREEs. Our results have implications for nuclear forensic analyses since a comparison is reported between the REE abundances for the CUP-2 (processed uranium ore) certified reference material and previously determined values for uranium ore concentrate (UOC) produced from the same U deposit (Blind River/Elliott Lake, Canada). UOCs represent the most common form of interdicted nuclear material and consequently is material frequently targeted for forensic analysis. The comparison reveals similar chondrite normalized REE signatures but variable absolute abundances. Based on the results reported here, the

Rare-earth element fractionation in uranium ore and its U(VI) alteration minerals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balboni, Enrica; Spano, T; Cook, N

We developed a cation exchange chromatography method employing sulfonated polysterene cation resin (DOWEX AG50-X8) in order to separate rare-earth elements (REEs) from uranium-rich materials. The chemical separation scheme is designed to reduce matrix effects and consequently yield enhanced ionization efficiencies for concentration determinations of REEs without significant fractionation using solution mode-inductively coupled plasma mass spectrometry (ICP-MS) analysis. This method was then applied to determine REE abundances in four uraninite (ideally UO 2) samples and their associated U(VI) alteration minerals. In three of the samples analyzed, the concentration of REEs for primary uraninite are higher than those for their corresponding secondarymore » uranium alteration phases. The results for U(VI) alteration minerals of two samples indicate enrichment of the light REEs (LREEs) over the heavy REEs (HREEs). This differential mobilization is attributed to differences in the mineralogical composition of the U(VI) alteration. There is a lack of fractionation of the LREEs in the uraninite alteration rind that is composed of U(VI) minerals containing Ca 2+ as the interlayer cation (uranophane and bequerelite); contrarily, U(VI) alteration minerals containing K + and Pb 2+ as interlayer cations (fourmarierite, dumontite) indicate fractionation (enrichment) of the LREEs. Our results have implications for nuclear forensic analyses since a comparison is reported between the REE abundances for the CUP-2 (processed uranium ore) certified reference material and previously determined values for uranium ore concentrate (UOC) produced from the same U deposit (Blind River/Elliott Lake, Canada). UOCs represent the most common form of interdicted nuclear material and consequently is material frequently targeted for forensic analysis. The comparison reveals similar chondrite normalized REE signatures but variable absolute abundances. Based on the results reported here, the

Oxidation of octylphenol by ferrate(VI).

PubMed

Anquandah, George A K; Sharma, Virender K

2009-01-01

The rates of the oxidation of octylphenols (OP) by potassium ferrate(VI) (K(2)FeO(4)) in water were determined as a function of pH (8.0-10.9) at 25 degrees C. The rate law for the oxidation of OP by Fe(VI) was found to be first order with each reactant. The observed second-order rate constants, k(obs), for the oxidation of alkylphenols decreased with an increase in pH. The speciation of Fe(VI) (HFeO(4)(-) and FeO(4)(2 -)) and OP (OP-OH and OP-O(-)) species were used to determine individual rate constants of the reactions. Comparison of rate constants and half-lives of oxidation of OP by Fe(VI) with nonylphenol (NP) and bisphenol-A (BPA) were conducted to demonstrate that Fe(VI) efficiently oxidizes environmentally relevant alkylphenols in water.

The biomineralization process of uranium(VI) by Saccharomyces cerevisiae - transformation from amorphous U(VI) to crystalline chernikovite.

PubMed

Shen, Yanghao; Zheng, Xinyan; Wang, Xiaoyu; Wang, Tieshan

2018-05-01

Microorganisms play a significant role in uranium(VI) biogeochemistry and influence U(VI) transformation through biomineralization. In the present work, the process of uranium mineralization was investigated by Saccharomyces cerevisiae. The toxicity experiments showed that the viability of cell was not significantly affected by 100 mg L -1 U(VI) under 4 days of exposure time. The batch experiments showed that the phosphate concentration and pH value increased over time during U(VI) adsorption. Meanwhile, thermodynamic calculations demonstrated that the adsorption system was supersaturated with respect to UO 2 HPO 4 . The X-ray powder diffraction spectroscopy (XRD), field emission scanning electron microscopy (FE-SEM) equipped with energy dispersive spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analyses indicated that the U(VI) was first attached onto the cell surface and reacted with hydroxyl, carboxyl, and phosphate groups through electrostatic interactions and complexation. As the immobilization of U(VI) transformed it from the ionic to the amorphous state, lamellar uranium precipitate was formed on the cell surface. With the prolongation of time, the amorphous uranium compound disappeared, and there were some crystalline substances observed extracellularly, which were well-characterized as tetragonal-chernikovite. Furthermore, the size of chernikovite was regulated at nano-level by cells, and the perfect crystal was formed finally. These findings provided an understanding of the non-reductive transformation process of U(VI) from the amorphous to crystalline state within microbe systems, which would be beneficial for the U(VI) treatment and reuse of nuclides and heavy metals.

Cervical Infection with Herpes simplex Virus, Chlamydia trachomatis, and Neisseria gonorrhoeae among Symptomatic Women, Dubai, UAE: A Molecular Approach

PubMed Central

Behzadi, Mohammad Amin; Azizi, Saeed; Payombarnia, Hamid; Vahdani, Ali; Namayandeh, Mandana; Ziyaeyan, Mazyar

2014-01-01

Tragically, genital tract infections are still a major public health problem in many regions. This study was undertaken to determine the prevalence of cervical infection with Herpes simplex virus (HSV), Chlamydia trachomatis (CT), and Neisseria gonorrhoeae (NG) among married women referring to Iranian Hospital, Dubai, UAE. In a retrospective cross-sectional survey, 201 female patients aged 16–80 years who referred to the Obstetrics and Gynecology Department of Iranian Hospital, Dubai, UAE, in 2010 were enrolled. The patients were categorized into three age groups: 15–30 (group I), 31–40 (group II), and ≥41 years old (group III). A cervical swab sample was collected from each woman and the prevalence of cervical infection with HSV, CT, and NG was determined by PCR method. HSV, CT, and NG were detected in 6.5%, 10.4%, and 5.5% of swab samples, respectively. Regarding age, a significant difference was noticed for prevalence of NG and HSV between groups I and III. Because of public health importance of sexual transmitted diseases (STDs), their long-lasting impact on quality of life, and their economic burden, preventing measures and education of women seem necessary. PMID:24982675

Negotiating weight and body image in the UAE: strategies among young Emirati women.

PubMed

Trainer, Sarah

2012-01-01

The goal of this study was to evaluate weight, nutritional status, and attitudes toward weight and health among a cohort of young women drawn from local populations in the United Arab Emirates. This sample was composed of 103 female Emiratis, aged 18-30. Eighty of the women were students at Zayed University (ZU) in Dubai and 23 were students at UAE University (UAEU) in Al Ain. Research was divided into two phases. Methods included the collection of weight and height measurements (to analyze BMIs) and body fat percentages; 24-h food and activity recalls; semistructured, structured, and unstructured interviews; and participant observation. The distribution of BMIs in this sample was skewed toward underweight and normal weight in the ZU sample and split evenly between underweight-to-normal and overweight-to-obese in the UAEU sample, a finding that stands in contrast to the high rates of overweight and obesity reported in other age cohorts in local populations. This lower distribution of BMIs was correlated with widely expressed concern over body image, whereas reported interest in nutrition was much lower. Dietary patterns reflected attempts to manage weight. There was a marked trend toward nutritionally poor diets and sedentary living. Obesity and overweight among young women in the Emirati population do not appear to be as significant a problem as they are in older populations. However, several other health-related causes for concern emerged in this study, including extreme dieting strategies, insufficient micronutrient and protein intake, and widespread inactivity. Copyright © 2012 Wiley Periodicals, Inc.

The new geographic information system in ETVA VI.PE.

NASA Astrophysics Data System (ADS)

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.

Cross-national study of attitudes towards seeking professional help: Jordan, United Arab Emirates (UAE) and Arabs in Israel.

PubMed

Al-Krenawi, Alean; Graham, John R; Dean, Yasmin Z; Eltaiba, Nada

2004-06-01

Help-seeking processes provide critical links between the onset of mental health problems and the provision of professional care. But little is known about these processes in the Arab world, and still less in transnational, comparative terms. This is the first study to compare help-seeking processes among Muslim Arab female students in Jordan, the United Arab Emirates and Israel. The present study compares the attitudes of Arab Muslim female students from Israel, Jordan and the United Arab Emirates (UAE) towards mental health treatment. A convenience sample of 262 female Muslim-Arab undergraduate university students from Jordan, United Arab Emirates (UAE) and Arab students in Israel completed a modified Orientation for Seeking Professional Help (OSPH) Questionnaire. Data revealed that nationality was not statistically significant as a variable in a positive attitude towards seeking professional help; year of study, marital status and age were found to be significant predictors of a positive attitude towards seeking help. High proportions of respondents among the nationalities referred to God through prayer during times of psychological distress. The discussion considers implications for professional service delivery and programme development. Future research could extrapolate findings to other Arab countries and to Arab peoples living in the non-Arab world.

The Vi conjugate typhoid vaccine is safe, elicits protective levels of IgG anti-Vi, and is compatible with routine infant vaccines.

PubMed

Thiem, Vu Dinh; Lin, Feng-Ying C; Canh, Do Gia; Son, Nguyen Hong; Anh, Dang Duc; Mao, Nguyen Duc; Chu, Chiayung; Hunt, Steven W; Robbins, John B; Schneerson, Rachel; Szu, Shousun C

2011-05-01

Typhoid fever remains a serious problem in developing countries. Current vaccines are licensed for individuals who are 5 years old or older. A conjugate of the capsular polysaccharide (CP) of Salmonella enterica serovar Typhi (Vi) bound to recombinant exoprotein A of Pseudomonas aeruginosa (Vi-rEPA) enhanced Vi immunogenicity and protected 2- to 5-year-olds in Vietnam. In this study, Vi-rEPA was evaluated for use in infants. A total of 301 full-term Vietnamese infants received Expanded Program on Immunization (EPI) vaccines alone or with Vi-rEPA or Haemophilus influenzae type b-tetanus toxoid conjugate (Hib-TT) at 2, 4, and 6 months and Vi-rEPA or Hib-TT alone at 12 months. Infants were visited 6, 24, and 48 h after each injection to monitor adverse reactions. Maternal, cord, and infant sera were assayed for IgG anti-Vi and for IgG antibodies to Hib CP and the diphtheria, tetanus, and pertussis toxins at 7, 12, and 13 months. No vaccine-related serious adverse reactions occurred. In the Vi-rEPA group, the IgG anti-Vi geometric mean (GM) increased from the cord level of 0.66 to 17.4 enzyme-linked immunosorbent assay units (EU) at 7 months, declined to 4.76 EU at 12 months, and increased to 50.1 EU 1 month after the 4th dose (95% of infants had levels of ≥ 3.5 EU, the estimated protective level). Controls had no increase of the IgG anti-Vi GM. Infants with cord anti-Vi levels of <3.5 EU responded with significantly higher IgG anti-Vi levels than those with levels of ≥ 3.5 EU. Anti-diphtheria, -tetanus, and -pertussis toxin levels were similar in all groups. Vi-rEPA was safe, induced protective anti-Vi levels, and was compatible with EPI vaccines, and it can be used in infants. High cord IgG anti-Vi levels partially suppressed infant responses to Vi-rEPA.

Research Priorities for School Nursing in the United Arab Emirates (UAE).

PubMed

Al-Yateem, Nabeel; Docherty, Charles; Brenner, Maria; Alhosany, Jameela; Altawil, Hanan; Al-Tamimi, Muna

2017-10-01

School nurses are challenged with more children having complex conditions, who are now surviving into school age. This is paralleled by a shift in focus of health systems toward primary care, and national efforts to develop the health-care services, especially those offered to vulnerable populations. Being at the forefront of this change, school nurses in United Arab Emirates (UAE) are finding themselves under pressure to adapt to and facilitate these changes both by improving their practice and by contributing to its underpinning evidence. A cross-sectional design was used in this study in which 370 school nurses participated, identifying 11 research priorities. The three most important, as ranked by participants, were management of children with complex health-care needs; nutrition, obesity, and lifestyle issues of schoolchildren; and managing illnesses, injuries, and emergencies in schools and provision of medical support. These priorities should direct future research activities in the field.

Factors Affecting Formation of Incomplete Vi Antibody in Mice

PubMed Central

Gaines, Sidney; Currie, Julius A.; Tully, Joseph G.

1965-01-01

Gaines, Sidney (Walter Reed Army Institute of Research, Washington, D.C.), Julius A. Currie, and Joseph G. Tully. Factors affecting formation of incomplete Vi antibody in mice. J. Bacteriol. 90:635–642. 1965.—Single immunizing doses of purified Vi antigen elicited complete and incomplete Vi antibodies in BALB/c mice, but only incomplete antibody in Cinnamon mice. Three of six other mouse strains tested responded like BALB/c mice; the remaining three, like Cinnamon mice. Varying the quantity of antigen injected or the route of administration failed to stimulate the production of detectable complete Vi antibody in Cinnamon mice. Such antibody was evoked in these animals by multiple injections of Vi antigen or by inoculating them with Vi-containing bacilli or Vi-coated erythrocytes. The early protection afforded by serum from Vi-immunized BALB/c mice coincided with the appearance of incomplete Vi antibody, 1 day prior to the advent of complete antibody. Persistence of incomplete as well as complete antibody in the serum of immunized mice was demonstrated for at least 56 days after injection of 10 μg of Vi antigen. Incomplete Vi antibody was shown to have blocking ability, in vitro bactericidal activity, and the capability of protecting mice against intracerebral as well as intraperitoneal challenge with virulent typhoid bacilli. Production of incomplete and complete Vi antibodies was adversely affected by immunization with partially depolymerized Vi antigens. PMID:16562060

77 FR 52116 - Title VI; Final Circular

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-28

... DEPARTMENT OF TRANSPORTATION Federal Transit Administration [Docket No. FTA-2011-0054] Title VI... Web site, guidance in the form of a Circular to assist grantees in complying with Title VI of the... Title VI regulations (49 CFR part 21). DATES: Effective Date: The effective date of the Circular is...

Satellite-based retrieval of particulate matter concentrations over the United Arab Emirates (UAE)

NASA Astrophysics Data System (ADS)

Zhao, Jun; Temimi, Marouane; Hareb, Fahad; Eibedingil, Iyasu

2016-04-01

In this study, an empirical algorithm was established to retrieve particulate matter (PM) concentrations (PM2.5 and PM10) using satellite-derived aerosol optical depth (AOD) over the United Arab Emirates (UAE). Validation of the proposed algorithm using ground truth data demonstrates its good accuracy. Time series of in situ measured PM concentrations between 2014 and 2015 showed high values in summer and low values in winter. Estimated and in situ measured PM concentrations were higher in 2015 than 2014. Remote sensing is an essential tool to reveal and back track the seasonality and inter-annual variations of PM concentrations and provide valuable information on the protection of human health and the response of air quality to anthropogenic activities and climate change.

Kinetic investigations of quinoline oxidation by ferrate(VI).

PubMed

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.

Identifying the need for a multidisciplinary approach for early recognition of mucopolysaccharidosis VI (MPS VI).

PubMed

Choy, Yew Sing; Bhattacharya, Kaustuv; Balasubramaniam, Shanti; Fietz, Michael; Fu, Antony; Inwood, Anita; Jin, Dong-Kyu; Kim, Ok-Hwa; Kosuga, Motomichi; Kwun, Young Hee; Lin, Hsiang-Yu; Lin, Shuan-Pei; Mendelsohn, Nancy J; Okuyama, Torayuki; Samion, Hasri; Tan, Adeline; Tanaka, Akemi; Thamkunanon, Verasak; Thong, Meow-Keong; Toh, Teck-Hock; Yang, Albert D; McGill, Jim

2015-05-01

Mucopolysaccharidosis VI (MPS VI, Maroteaux-Lamy syndrome) is caused by deficient activity of the enzyme, N-acetylgalactosamine-4-sulfatase, resulting in impaired degradation of the glycosaminoglycan dermatan sulfate. Patients experience a range of manifestations including joint contractures, short stature, dysostosis multiplex, coarse facial features, decreased pulmonary function, cardiac abnormalities, corneal clouding and shortened life span. Recently, clinicians from institutions in the Asia-Pacific region met to discuss the occurrence and implications of delayed diagnosis and misdiagnosis of MPS VI in the patients they have managed. Eighteen patients (44% female) were diagnosed. The most common sign presented by the patients was bone deformities in 11 patients (65%). Delays to diagnosis occurred due to the lack of or distance to diagnostic facilities for four patients (31%), alternative diagnoses for two patients (15%), and misleading symptoms experienced by two patients (15%). Several patients experienced manifestations that were subtler than would be expected and were subsequently overlooked. Several cases highlighted the unique challenges associated with diagnosing MPS VI from the perspective of different specialties and provide insights into how these patients initially present, which may help to elucidate strategies to improve the diagnosis of MPS VI. Copyright © 2015 Elsevier Inc. All rights reserved.

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

PubMed

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.

Coronal O VI emission observed with UVCS/SOHO during solar flares: Comparison with soft X-ray observations

NASA Astrophysics Data System (ADS)

Mancuso, S.; Giordano, S.; Raymond, J. C.

2016-06-01

In this work, we derive the O VI 1032 Å luminosity profiles of 58 flares, during their impulsive phase, based on off-limb measurements by the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the SOlar and Heliospheric Observatory (SOHO). The O VI luminosities from the transition region plasma (here defined as the region with temperatures 5.0 ≤ log T (K) ≤ 6.0) were inferred from the analysis of the resonantly scattered radiation of the O VI coronal ions. The temperature of maximum ionization for O VI is log Tmax (K) = 5.47. By comparison with simultaneous soft X-ray measurements, we investigate the likely source (chromospheric evaporation, footpoint emission, or heated prominence ejecta) for the transition region emission observed during the impulsive phase. In our study, we find evidence of the main characteristics predicted by the evaporation scenario. Specifically, most O VI flares precede the X-ray peaks typically by several minutes with a mean of 3.2 ± 0.1 min, and clear correlations are found between the soft X-ray and transition region luminosities following power laws with indices ~ 0.7 ± 0.3. Overall, the results are consistent with transition region emission originating from chromospheric evaporation; the thermal X-ray emission peaks after the emission from the evaporation flow as the loops fill with hot plasma. Finally, we were able to infer flow speeds in the range ~20-100 km s-1 for one-third of the events, 14 of which showed speeds between 60 and 80 km s-1. These values are compatible with those found through direct spectroscopic observations at transition region temperatures by the EUV Imaging Spectrometer (EIS) on board Hinode.

Electrochemical alkaline Fe(VI) water purification and remediation.

PubMed

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).

Myosin VI facilitates connexin 43 gap junction accretion.

PubMed

Waxse, Bennett J; Sengupta, Prabuddha; Hesketh, Geoffrey G; Lippincott-Schwartz, Jennifer; Buss, Folma

2017-03-01

In this study, we demonstrate myosin VI enrichment at Cx43 (also known as GJA1)-containing gap junctions (GJs) in heart tissue, primary cardiomyocytes and cell culture models. In primary cardiac tissue and in fibroblasts from the myosin VI-null mouse as well as in tissue culture cells transfected with siRNA against myosin VI, we observe reduced GJ plaque size with a concomitant reduction in intercellular communication, as shown by fluorescence recovery after photobleaching (FRAP) and a new method of selective calcein administration. Analysis of the molecular role of myosin VI in Cx43 trafficking indicates that myosin VI is dispensable for the delivery of Cx43 to the cell surface and connexon movement in the plasma membrane. Furthermore, we cannot corroborate clathrin or Dab2 localization at gap junctions and we do not observe a function for the myosin-VI-Dab2 complex in clathrin-dependent endocytosis of annular gap junctions. Instead, we found that myosin VI was localized at the edge of Cx43 plaques by using total internal reflection fluorescence (TIRF) microscopy and use FRAP to identify a plaque accretion defect as the primary manifestation of myosin VI loss in Cx43 homeostasis. A fuller understanding of this derangement may explain the cardiomyopathy or gliosis associated with the loss of myosin VI. © 2017. Published by The Company of Biologists Ltd.

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

PubMed

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.

Spectroscopic studies of U(VI) sorption at the kaolinite-water interface. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, H.A.; Parks, G.A.; Brown, G.E. Jr.

Efficient use of U as a resource and safe handling, recycling and disposal of U-containing wastes require an understanding of the factors controlling the fate of U, where fate refers to the destination of U, typically expressed as an environmental medium or a process phase. The sorption process constitutes a change in elemental fate. Partitioning of an element from solution to a solid phase, or sorption, can be divided into three broad categories: adsorption, surface precipitation, and absorption. Extended X-ray absorption fine structure (EXAFS), a type of X-ray absorption spectroscopy (XAS), offers the possibility for distinguishing among different modes ofmore » sorption by characterizing the atomic environment of the sorbing element. In this study, the authors use EXAFS to determine the structure of U(VI) sorption complexes at the kaolinite-water interface. In Chapter One, they present an overview of selected aspects of U structural chemistry as a basis for considering the structural environment of U at the solid-water interface. To evaluate the utility of XAS for characterization of the structural environment of U(VI) at the solid-water interface, they have carried out an in-depth analysis of XAS data from U(VI)-containing solid and solution model compounds, which they describe in Chapter Two. In Chapter three, they consider sorption of U by kaolinite as a means of effecting the removal of U from surface collection pond waters on the Rocky Flats Plant site in northern Colorado.« less

United Arab Emirates (UAE): regional and global dimensions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Nabeh, N.A.

1984-01-01

The study traces the background and development of the United Arab Emirates as a federal entity in an essentially tribal culture. It also identifies and discusses the political dynamics that form the vital region in which the Union has emerged, the function played by major regional individuals in this emergence, and the importance of this part of the Middle East in the conception of foreign policy makers of the super powers. The issues of the regional economic policies resulted in formation of the Gulf Cooperation Council (GCC) in 1981 among six Arab Gulf countries: Bahrain, Kuwait, Oman, Qatar, Saudi Arabia,more » and the United Arab Emirates. Formation of the GCC was an essential step toward the comprehensive economic development of the region. One of the conclusions is that the attainment of socio-economic and political development is not a necessary condition for the emergence of a federal structure among highly authoritarian and formalistic political systems. The emergence of the UAE took place mainly as a consequence of the conception by pertinent political elites of the inability of the emirates to individually assume the responsibilities of statehood in a highly complicated world, and in light of the poor material and human resources each commanded after over a century of dependence on a foreign power.« less

Anion Exchange in II-VI Semiconducting Nanostructures via Atomic Templating.

PubMed

Agarwal, Rahul; Krook, Nadia M; Ren, Ming-Liang; Tan, Liang Z; Liu, Wenjing; Rappe, Andrew M; Agarwal, Ritesh

2018-03-14

Controlled chemical transformation of nanostructures is a promising technique to obtain precisely designed novel materials, which are difficult to synthesize otherwise. We report high-temperature vapor-phase anion-exchange reactions to chemically transform II-VI semiconductor nanostructures (100-300 nm length scale) while retaining the single crystallinity, crystal structure, morphology, and even defect distribution of the parent material via atomic templating. The concept of atomic templating is employed to obtain kinetically controlled, thermodynamically metastable structural phases such as zincblende CdSe and CdS from zincblende CdTe upon complete chemical replacement of Te with Se or S. The underlying transformation mechanisms are explained through first-principles density functional theory calculations. Atomic templating is a unique path to independently tune materials' phase and composition at the nanoscale, allowing the synthesis of novel materials.

Cast Aluminum Structures Technology (CAST) Phase VI. Technology Transfer.

DTIC Science & Technology

1980-04-01

and other aspects of the program was provided as follows: o Phase I--Preliminary Design Richard C. Jones o Phase il--Manufacturing Methods Richard G...Christner o Phase Ill--Detailed Design Richard C. Jones o Phase IV--Fabrication of Demonstration Richard G. Christner Articles and Production... Richard C. Jones, assisted by Carlos J. Romero, Christian K. Gunther, Cecil E. Parsons, and Donald D. Goehler; and by Walter Hyler of Battelle Columbus

Title VI Summary 2000-2001.

ERIC Educational Resources Information Center

Huskey, Barton

Title VI provides federal funds to states under the Elementary and Secondary Education Act of 1965. This document describes Title VI programs and the use of funds in the Austin Independent School District (AISD), Texas for 2000-2001. The AISD allocation of $481,559 was based on the May 2000 projected school enrollment, including projected…

Screening and correlates of depression and HbA1 C in United Arab Emirates (UAE) women with diabetes.

PubMed

Hawamdeh, Sana; Almakhzoomy, Ibtihal; Hayajneh, Yaseen

2013-10-01

The aim was to identify the relationship between socio-demographic characteristics of United Arab Emirates (UAE) women with diabetes and depression and to explore any differences between depressed and nondepressed patients in relation to glycemic control. One hundred eighty-two subjects completed the Beck Depression Inventory-II and a socio-demographic questionnaire (i.e., age, national status, economic status, level of education, and employment status). Glycemic control was assessed by glycosylated hemoglobin (HbA1C ). Ninety-two subjects were diagnosed with diabetes mellitus. A statistically significant higher incidence of depression was found in the subject group with diagnosed diabetes mellitus than in the nondiabetic subject group. A statistically significant relationship was found between depression status and type of diabetes (Type 1). A positive relationship between poor glycemic control and higher levels of depression was identified. A positively significant relationship was found between national status and level of depression among the diabetic sample, among whom at least half showed poor glycemic control (HbA1C levels > 7.5). Early detection of depression among women with diabetes is crucial to enhance treatment regimen adherence and glycemic control. As the UAE diabetic women are at even greater risk than other diabetic women, they need to be very carefully screened and evaluated for depression. © 2013 Wiley Periodicals, Inc.

O VI ABSORBERS TRACING HOT GAS ASSOCIATED WITH A PAIR OF GALAXIES AT z = 0.167

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savage, B. D.; Narayanan, A.; Wakker, B. P.

2010-08-20

High signal-to-noise observations of the QSO PKS 0405-123 (z {sub em} = 0.572) with the Cosmic Origins Spectrograph from 1134 to 1796 A with a resolution of {approx}17 km s{sup -1} are used to study the multi-phase partial Lyman limit system (LLS) at z = 0.16716, which has previously been studied using relatively low signal-to-noise spectra from STIS and FUSE. The LLS and an associated H I-free broad O VI absorber likely originate in the circumgalactic gas associated with a pair of galaxies at z = 0.1688 and 0.1670 with impact parameters of 116 h {sup -1} {sub 70} andmore » 99 h {sup -1} {sub 70}. The broad and symmetric O VI absorption is detected in the z = 0.16716 rest frame with v = -278 {+-} 3 km s{sup -1}, log N(O VI) = 13.90 {+-} 0.03, and b = 52 {+-} 2 km s{sup -1}. This absorber is not detected in H I or other species with the possible exception of N V. The broad, symmetric O VI profile and the absence of corresponding H I absorption indicate that the circumgalactic gas in which the collisionally ionized O VI arises is hot (log T {approx} 5.8-6.2). The absorber may represent a rare but important new class of low-z intergalactic medium absorbers. The LLS has strong asymmetrical O VI absorption with log N(O VI) = 14.72 {+-} 0.02 spanning a velocity range from -200 to +100 km s{sup -1}. The high and low ions in the LLS have properties resembling those found for Galactic highly ionized high-velocity clouds where the O VI is likely produced in the conductive and turbulent interfaces between cool and hot gas.« less

Preparation and application of sustained release microcapsules of potassium ferrate(VI) for dinitro butyl phenol (DNBP) wastewater treatment.

PubMed

Wang, Hui-Long; Liu, Shu-Qin; Zhang, Xiu-Yan

2009-09-30

The encapsulated potassium ferrate(VI) (K(2)FeO(4)) samples were successfully prepared by phase separation method in organic solvents. The ethyl cellulose and paraffin were selected for the microcapsule wall materials (WM). The as prepared microcapsules were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The stability can be enhanced greatly when ferrate(VI) was encapsulated in the microcapsules with a mass ratio of Fe(VI):WM in the range of 1:1-1:3 for the same conserved time in air compared for pure K(2)FeO(4). The sustained release behavior of the microcapsules with different Fe(VI):WM mass ratios in 8.0M KOH solution was also investigated. The results indicated that the Fe(VI) release was reduced with increase of Fe(VI):WM mass ratios from 1:1 to 1:3. The release kinetics of the microcapsules is found to obey Ritger-Peppas equation. The prepared Fe(VI) microcapsules has been used for the removal of a typical alkyl dinitro phenol compound, 2-sec-butyl-4,6-dinitrophenol (DNBP), from aqueous solution. The effect of pH, microcapsule concentration and reaction time was studied thoroughly. The optimal pH for DNBP degradation was 6.5, and at this pH and a microcapsule concentration of 1.2g/L, approximately 93% of the DNBP was degraded after 80 min. The encapsulated ferrate(VI) samples were found to be very effective in the decolorization and COD reduction of real wastewater from DNBP manufacturing. Thus, this study showed the feasible and potential use of encapsulated Fe(VI) samples in degradation of various toxic organic contaminants and industrial effluents.

Incorporation of zero valent iron nanoparticles in the matrix of cationic resin beads for the remediation of Cr(VI) contaminated waters.

PubMed

Toli, Aikaterini; Chalastara, Konstantina; Mystrioti, Christiana; Xenidis, Anthimos; Papassiopi, Nymphodora

2016-07-01

The objective of present study was to obtain the fixation of nano zero valent iron (nZVI) particles on a permeable matrix and evaluate the performance of this composite material for the removal of Cr(VI) from contaminated waters. The experiments were carried out using the cationic resin Dowex 50WX2 as porous support of the iron nanoparticles. The work was carried out in two phases. The first phase involved the fixation of nZVI on the resin matrix. The resin granules were initially mixed with a FeCl3 solution to obtain the adsorption of Fe(III). Then the Fe(III) loaded resin (RFe) was treated with polyphenol solutions to obtain the reduction of Fe(III) to the elemental state. Two polyphenol solutions were tested as reductants, i.e. green tea extract and gallic acid. Green tea was found to be inefficient, probably due to the relatively big size of the contained polyphenol molecules, but gallic acid molecules were able to reach adsorbed Fe(III) and reduce the cations to the elemental state. The second phase was focused on the investigation of Cr(VI) reduction kinetics using the nanoiron loaded resins (R-nFe). It was found that the reduction follows a kinetic law of first order with respect to Cr(VI) and to the embedded nanoiron. Compared to other similar products, this composite material was found to have comparable performance regarding reaction rates and higher degree of iron utilization. Namely the rate constant for the reduction of Cr(VI), in the presence of 1 mM nZVI, was equivalent to 1.4 h of half-life time at pH 3.2 and increased to 24 h at pH 8.5. The degree of iron utilization was as high as 0.8 mol of reduced Cr(VI) per mole of iron. It was also found that this composite material can be easily regenerated and reused for Cr(VI) reduction without significant loss of efficiency. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

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

Synthesis, characterization and application of Lagerstroemia speciosa embedded magnetic nanoparticle for Cr(VI) adsorption from aqueous solution.

PubMed

Srivastava, Shalini; Agrawal, Shashi Bhushan; Mondal, Monoj Kumar

2017-05-01

Lagerstroemia speciosa bark (LB) embedded magnetic nanoparticles were prepared by co-precipitation of Fe 2+ and Fe 3+ salt solution with ammonia and LB for Cr(VI) removal from aqueous solution. The native LB, magnetic nanoparticle (MNP), L. speciosa embedded magnetic nanoparticle (MNPLB) and Cr(VI) adsorbed MNPLB particles were characterized by SEM-EDX, TEM, BET-surface area, FT-IR, XRD and TGA methods. TEM analysis confirmed nearly spherical shape of MNP with an average diameter of 8.76nm and the surface modification did not result in the phase change of MNP as established by XRD analysis, while led to the formation of secondary particles of MNPLB with diameter of 18.54nm. Characterization results revealed covalent binding between the hydroxyl group of MNP and carboxyl group of LB particles and further confirmed its physico-chemical nature favorable for Cr(VI) adsorption. The Cr(VI) adsorption on to MNPLB particle as an adsorbent was tested under different contact time, initial Cr(VI) concentration, adsorbent dose, initial pH, temperature and agitation speed. The results of the equilibrium and kinetics of adsorption were well described by Langmuir isotherm and pseudo-second-order model, respectively. The thermodynamic parameters suggest spontaneous and endothermic nature of Cr(VI) adsorption onto MNPLB. The maximum adsorption capacity for MNPLB was calculated to be 434.78mg/g and these particles even after Cr(VI) adsorption were collected effortlessly from the aqueous solution by a magnet. The desorption of Cr(VI)-adsorbed MNPLB was found to be more than 93.72% with spent MNPLB depicting eleven successive adsorption-desorption cycles. Copyright © 2016. Published by Elsevier B.V.

Ferrate(VI) oxidation of cyanide in water.

PubMed

Costarramone, N; Kneip, A; Castetbon, A

2004-08-01

Experiments were conducted to test removal of cyanide (free cyanide and several cyanide complexes) in water, under alkaline medium (pH > or = 11), by a new potassium ferrate salt. The removal rate of free cyanide by oxidation with Fe(VI) was greater at pH 11.0 than at pH 12.0. A complete oxidation was obtained with a 2.67 Fe(VI)/CN ratio at pH 11.0. In these conditions, the rate of cyanide oxidation by Fe(VI) was slow, with a reaction rate constant estimated at 0.95 +/- 0.10 s(-1) l mol(-1) at pH 11.0 and 19.6 degrees C in this study. This study revealed that Fe(VI) did not decompose all cyanide complexes. Copper, cadmium and zinc complexes were removed efficiently by Fe(VI). Moreover, these metals were also removed from the solution by coagulation effect of Fe(OH)3, the Fe(VI) product of reaction. A particular behaviour was reported with copper, as a rapid oxidation of cyanide was observed in the presence of this metal. On the contrary, oxidation of nickel and silver complexes was incomplete.

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

PubMed

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.

Enzyme replacement therapy for mucopolysaccharidosis VI: Growth and pubertal development in patients treated with recombinant human N-acetylgalactosamine 4-sulfatase

PubMed Central

Decker, Celeste; Yu, Zi-Fan; Giugliani, Roberto; Schwartz, Ida Vanessa D.; Guffon, Nathalie; Teles, Elisa Leão; Miranda, M. Clara Sá; Wraith, J. Edmond; Beck, Michael; Arash, Laila; Scarpa, Maurizio; Ketteridge, David; Hopwood, John J.; Plecko, Barbara; Steiner, Robert; Whitley, Chester B.; Kaplan, Paige; Swiedler, Stuart J.; Conrad, Susan; Harmatz, Paul

2010-01-01

Background and Methods Growth failure is characteristic of untreated mucopolysaccharidosis type VI (MPS VI: Maroteaux-Lamy syndrome). Growth was studied in fifty-six MPS VI patients (5 to 29 years old) prior to and for up to 240 weeks of weekly infusions of recombinant human arylsulfatase B (rhASB) at 1 mg/kg during Phase 1/2, Phase 2, Phase 3 or Phase 3 Extension clinical trials. Height, weight, and Tanner stage data were collected. Pooled data were analyzed to determine mean height increase by treatment week, growth impacts of pubertal status, baseline urinary GAG, and age at treatment initiation. Growth rate for approximately 2 years prior to and following treatment initiation was analyzed using longitudinal modeling. Results Mean height increased by 2.9 cm after 48 weeks and 4.3 cm after 96 weeks on enzyme replacement therapy (ERT). Growth on ERT was not correlated with baseline urinary GAG. Patients under 16 years of age showed greatest increases in height on treatment. Model results based on pooled data showed significant improvement in growth rate during 96 weeks of ERT when compared to the equivalent pretreatment time period. Delayed pubertal onset or progression was noted in 10 patients entering the clinical trials; all of whom showed progression of at least one Tanner stage during 2 years on ERT, and 6 of whom (60%) completed puberty. Conclusion Analysis of mean height by treatment week and longitudinal modeling demonstrate significant increase in height and growth rate in MPS VI patients receiving long-term ERT. This impact was greatest in patients aged below 16 years. Height increase may result from bone growth and/or reduction in joint contractures. Bone growth and resolution of delayed puberty may be related to improvements in general health, bone cell health, nutrition, endocrine gland function and reduced inflammation. PMID:20634905

Emissions of chromium (VI) from arc welding.

PubMed

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.

The redox chemistry of neptunium in γ-irradiated aqueous nitric acid in the presence of an organic phase

DOE PAGES

Mincher, Bruce J.; Precek, Martin; Paulenova, Alena

2015-10-17

The radiolytic changes in oxidation state for solutions of initially Np(V) and/or Np(VI) were investigated by gamma-irradiation in conjunction with UV/Vis spectroscopy of the aqueous phase. Samples were irradiated in varying concentrations of nitric acid, and with or without the presence of 30% TBP in dodecane. At short irradiation times Np(V) was oxidized to Np(VI), even in the presence of the organic phase. Upon the radiolytic production of sufficient amounts of nitrous acid, reduction of Np(VI) to Np(V) occurred in both phases. This was accompanied by stripping of the previously extracted Np(VI). Nitric acid concentrations of 6 M mitigated thismore » reduction.« less

The redox chemistry of neptunium in γ-irradiated aqueous nitric acid in the presence of an organic phase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mincher, Bruce J.; Precek, Martin; Paulenova, Alena

The radiolytic changes in oxidation state for solutions of initially Np(V) and/or Np(VI) were investigated by gamma-irradiation in conjunction with UV/Vis spectroscopy of the aqueous phase. Samples were irradiated in varying concentrations of nitric acid, and with or without the presence of 30% TBP in dodecane. At short irradiation times Np(V) was oxidized to Np(VI), even in the presence of the organic phase. Upon the radiolytic production of sufficient amounts of nitrous acid, reduction of Np(VI) to Np(V) occurred in both phases. This was accompanied by stripping of the previously extracted Np(VI). Nitric acid concentrations of 6 M mitigated thismore » reduction.« less

Reduction of Fe(III), Cr(VI), U(VI), and Tc(VII) by Deinococcus radiodurans R1

PubMed Central

Fredrickson, J. K.; Kostandarithes, H. M.; Li, S. W.; Plymale, A. E.; Daly, M. J.

2000-01-01

Deinococcus radiodurans is an exceptionally radiation-resistant microorganism capable of surviving acute exposures to ionizing radiation doses of 15,000 Gy and previously described as having a strictly aerobic respiratory metabolism. Under strict anaerobic conditions, D. radiodurans R1 reduced Fe(III)-nitrilotriacetic acid coupled to the oxidation of lactate to CO2 and acetate but was unable to link this process to growth. D. radiodurans reduced the humic acid analog anthraquinone-2,6-disulfonate (AQDS) to its dihydroquinone form, AH2DS, which subsequently transferred electrons to the Fe(III) oxides hydrous ferric oxide and goethite via a previously described electron shuttle mechanism. D. radiodurans reduced the solid-phase Fe(III) oxides in the presence of either 0.1 mM AQDS or leonardite humic acids (2 mg ml−1) but not in their absence. D. radiodurans also reduced U(VI) and Tc(VII) in the presence of AQDS. In contrast, Cr(VI) was directly reduced in anaerobic cultures with lactate although the rate of reduction was higher in the presence of AQDS. The results are the first evidence that D. radiodurans can reduce Fe(III) coupled to the oxidation of lactate or other organic compounds. Also, D. radiodurans, in combination with humic acids or synthetic electron shuttle agents, can reduce U and Tc and thus has potential applications for remediation of metal- and radionuclide-contaminated sites where ionizing radiation or other DNA-damaging agents may restrict the activity of more sensitive organisms. PMID:10788374

ETS-VI multibeam satellite communications systems

NASA Astrophysics Data System (ADS)

Kawai, Makoto; Tanaka, Masayoshi; Ohtomo, Isao

1989-10-01

The fixed and mobile satellite communications systems of the Japanese Engineering Test Satellite-VI (ETS-VI) are described. The system requirements are outlined along with the system configuration. The ETS-VI multibeam system employs three frequency bands. When used for Ka-band fixed communications, it covers the Japanese main islands with thirteen 0.3-degree-wide spot beam. Four of the beams are active for ETS-VI. When used for S-band mobile communications, five beams cover the area within 200 nautical miles from the Japanese coast. The C-band beam for fixed communications covers the central area of the Japanese main islands with a single beam. The onboard antenna system is described along with the transponders and their associated onboard systems. A discussion of the system technology follows, covering the TDMA transmisssion system, the relay function, rainfall compensation, and the antenna and propagation performance.

Speciation and preservation of CrVI and CrIII in finished drinking water matrices using collision cell ion chromatography-inductively coupled plasma-mass spectrometry

EPA Science Inventory

The polyatomic background at the major isotope of Cr was evaluated as a function of collision cell gas flow rate using three different mobile phases. The stability of CrVI was evaluated as a function of solution pH using an enriched 53CrVI. The recovery was ≥ 95% at pH 7.8 but...

High pressure–low temperature phase diagram of barium: Simplicity versus complexity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Desgreniers, Serge; Tse, John S., E-mail: John.Tse@usask.ca; State Key Laboratory of Superhard Materials, Jilin University, 130012 Changchun

2015-11-30

Barium holds a distinctive position among all elements studied upon densification. Indeed, it was the first example shown to violate the long-standing notion that high compression of simple metals should preserve or yield close-packed structures. From modest pressure conditions at room temperature, barium transforms at higher pressures from its simple structures to the extraordinarily complex atomic arrangements of the incommensurate and self-hosting Ba-IV phases. By a detailed mapping of the pressure/temperature structures of barium, we demonstrate the existence of another crystalline arrangement of barium, Ba-VI, at low temperature and high pressure. The simple structure of Ba-VI is unlike that ofmore » complex Ba-IV, the phase encountered in a similar pressure range at room temperature. First-principles calculations predict Ba-VI to be stable at high pressure and superconductive. The results illustrate the complexity of the low temperature-high pressure phase diagram of barium and the significant effect of temperature on structural phase transformations.« less

Evaluation of activated carbon fiber supported nanoscale zero-valent iron for chromium (VI) removal from groundwater in a permeable reactive column.

PubMed

Qu, Guangzhou; Kou, Liqing; Wang, Tiecheng; Liang, Dongli; Hu, Shibin

2017-10-01

An activated carbon fiber supported nanoscale zero-valent iron (ACF-nZVI) composite for Cr(VI) removal from groundwater was synthesized according to the liquid phase reduction method. The techniques of N 2 adsorption/desorption, FESEM, EDX, XRD and XPS were used to characterize the ACF-nZVI composite and the interaction between the ACF-nZVI composite and Cr(VI) ions. Batch experiments were conducted to evaluate the effects of several factors, including the amount of nZVI on activated carbon fiber (ACF), pH value, initial Cr(VI) concentration, and co-existing ions on Cr(VI) removal. The results indicate that presence of ACF can inhibit the aggregation of nanoscale zero-valent iron (nZVI) particles and increase its reactivity, and the Cr(VI) removal efficiency increases with increasing amounts of nZVI on ACF and a decrease in the initial Cr(VI) concentration. In acidic conditions, almost 100% of Cr(VI) in solution can be removed after 60 min of reaction, and the removal efficiency decreases with increasing initial pH values. The Cr(VI) removal is also dependent on the co-existing ions. Reusability experiments on ACF-nZVI demonstrate that the ACF-nZVI composite can keep a high reactivity after five successive reduction cycles. The removal mechanisms are proposed as a two-step interaction including the physical adsorption of Cr(VI) on the surface or inner layers of the ACF-nZVI composite and the subsequent reduction of Cr(VI) to Cr(III) by nZVI. Copyright © 2017 Elsevier Ltd. All rights reserved.

Vi-da: vitiligo diagnostic assistance mobile application

NASA Astrophysics Data System (ADS)

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

NASA Astrophysics Data System (ADS)

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.

Biomineralization of U(VI) phosphate promoted by microbially-mediated phytate hydrolysis in contaminated soils

NASA Astrophysics Data System (ADS)

Salome, Kathleen R.; Beazley, Melanie J.; Webb, Samuel M.; Sobecky, Patricia A.; Taillefert, Martial

2017-01-01

The bioreduction of uranium may immobilize a significant fraction of this toxic contaminant in reduced environments at circumneutral pH. In oxic and low pH environments, however, the low solubility of U(VI)-phosphate minerals also makes them good candidates for the immobilization of U(VI) in the solid phase. As inorganic phosphate is generally scarce in soils, the biomineralization of U(VI)-phosphate minerals via microbially-mediated organophosphate hydrolysis may represent the main immobilization process of uranium in these environments. In this study, contaminated sediments were incubated aerobically in two pH conditions to examine whether phytate, a naturally-occurring and abundant organophosphate in soils, could represent a potential phosphorous source to promote U(VI)-phosphate biomineralization by natural microbial communities. While phytate hydrolysis was not evident at pH 7.0, nearly complete hydrolysis was observed both with and without electron donor at pH 5.5, suggesting indigenous microorganisms express acidic phytases in these sediments. While the rate of hydrolysis of phytate generally increased in the presence of uranium, the net rate of inorganic phosphate production in solution was decreased and inositol phosphate intermediates were generated in contrast to similar incubations conducted without uranium. These findings suggest uranium stress enhanced the phytate-metabolism of the microbial community, while simultaneously inhibiting phosphatase production and/or activity by the indigenous population. Finally, phytate hydrolysis drastically decreased uranium solubility, likely due to formation of ternary sorption complexes, U(VI)-phytate precipitates, and U(VI)-phosphate minerals. Overall, the results of this study provide evidence for the ability of natural microbial communities to liberate phosphate from phytate in acidic sediments, possibly as a detoxification mechanism, and demonstrate the potential utility of phytate-promoted uranium

Cranial mononeuropathy VI

MedlinePlus

... palsy; Cranial nerve VI palsy; Sixth nerve palsy; Neuropathy - sixth nerve ... with: Brain aneurysms Nerve damage from diabetes( diabetic neuropathy ) Gradenigo syndrome (which also causes discharge from the ...

Uranium(VI) Reduction by Anaeromyxobacter dehalogenans Strain 2CP-C

PubMed Central

Wu, Qingzhong; Sanford, Robert A.; Löffler, Frank E.

2006-01-01

Previous studies demonstrated growth of Anaeromyxobacter dehalogenans strain 2CP-C with acetate or hydrogen as the electron donor and Fe(III), nitrate, nitrite, fumarate, oxygen, or ortho-substituted halophenols as electron acceptors. In this study, we explored and characterized U(VI) reduction by strain 2CP-C. Cell suspensions of fumarate-grown 2CP-C cells reduced U(VI) to U(IV). More-detailed growth studies demonstrated that hydrogen was the required electron donor for U(VI) reduction and could not be replaced by acetate. The addition of nitrate to U(VI)-reducing cultures resulted in a transitory increase in U(VI) concentration, apparently caused by the reoxidation of reduced U(IV), but U(VI) reduction resumed following the consumption of N-oxyanions. Inhibition of U(VI) reduction occurred in cultures amended with Fe(III) citrate, or citrate. In the presence of amorphous Fe(III) oxide, U(VI) reduction proceeded to completion but the U(VI) reduction rates decreased threefold compared to control cultures. Fumarate and 2-chlorophenol had no inhibitory effects on U(VI) reduction, and both electron acceptors were consumed concomitantly with U(VI). Since cocontaminants (e.g., nitrate, halogenated compounds) and bioavailable ferric iron are often encountered at uranium-impacted sites, the metabolic versatility makes Anaeromyxobacter dehalogenans a promising model organism for studying the complex interaction of multiple electron acceptors in U(VI) reduction and immobilization. PMID:16672509

Simultaneous reduction of arsenic(V) and uranium(VI) by mackinawite: role of uranyl arsenate precipitate formation.

PubMed

Troyer, Lyndsay D; Tang, Yuanzhi; Borch, Thomas

2014-12-16

Uranium (U) and arsenic (As) often occur together naturally and, as a result, can be co-contaminants at sites of uranium mining and processing, yet few studies have examined the simultaneous redox dynamics of U and As. This study examines the influence of arsenate (As(V)) on the reduction of uranyl (U(VI)) by the redox-active mineral mackinawite (FeS). As(V) was added to systems containing 47 or 470 μM U(VI) at concentrations ranging from 0 to 640 μM. In the absence of As(V), U was completely removed from solution and fully reduced to nano-uraninite (nano-UO2). While the addition of As(V) did not reduce U uptake, at As(V) concentrations above 320 μM, the reduction of U(VI) was limited due to the formation of a trögerite-like uranyl arsenate precipitate. The presence of U also significantly inhibited As(V) reduction. While less U(VI) reduction to nano-UO2 may take place in systems with high As(V) concentrations, formation of trögerite-like mineral phases may be an acceptable reclamation end point due to their high stability under oxic conditions.

23 CFR 200.7 - FHWA Title VI policy.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false FHWA Title VI policy. 200.7 Section 200.7 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.7 FHWA Title VI policy. It is the policy of the FHWA to...

23 CFR 200.7 - FHWA Title VI policy.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false FHWA Title VI policy. 200.7 Section 200.7 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.7 FHWA Title VI policy. It is the policy of the FHWA to...

23 CFR 200.7 - FHWA Title VI policy.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false FHWA Title VI policy. 200.7 Section 200.7 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.7 FHWA Title VI policy. It is the policy of the FHWA to...

23 CFR 200.7 - FHWA Title VI policy.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false FHWA Title VI policy. 200.7 Section 200.7 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.7 FHWA Title VI policy. It is the policy of the FHWA to...

Approaches to surface complexation modeling of Uranium(VI) adsorption on aquifer sediments

NASA Astrophysics Data System (ADS)

Davis, James A.; Meece, David E.; Kohler, Matthias; Curtis, Gary P.

2004-09-01

surface functional groups available for adsorption in the surface coatings; 2) the electric field at the mineral-water interface; and 3) surface reactions of major ions in the aqueous phase, such as Ca 2+, Mg 2+, HCO 3-, SO 42-, H 4SiO 4, and organic acids. In contrast, a semi-empirical surface complexation modeling approach can be used to describe the U(VI) experimental data more precisely as a function of aqueous chemical conditions. This approach is useful as a tool to describe the variation in U(VI) retardation as a function of chemical conditions in field-scale reactive transport simulations, and the approach can be used at other field sites. However, the semi-empirical approach is limited by the site-specific nature of the model parameters.

Approaches to surface complexation modeling of Uranium(VI) adsorption on aquifer sediments

USGS Publications Warehouse

Davis, J.A.; Meece, D.E.; Kohler, M.; Curtis, G.P.

2004-01-01

surface functional groups available for adsorption in the surface coatings; 2) the electric field at the mineral-water interface; and 3) surface reactions of major ions in the aqueous phase, such as Ca2+, Mg2+, HCO3-, SO42-, H4SiO4, and organic acids. In contrast, a semi-empirical surface complexation modeling approach can be used to describe the U(VI) experimental data more precisely as a function of aqueous chemical conditions. This approach is useful as a tool to describe the variation in U(VI) retardation as a function of chemical conditions in field-scale reactive transport simulations, and the approach can be used at other field sites. However, the semi-empirical approach is limited by the site-specific nature of the model parameters. ?? 2004 Elsevier Ltd.

The fujairah united arab emirates (uae) (ml = 5.1) earthquake of march 11, 2002 a reminder for the immediate need to develop and implement a national hazard mitigation strategy

NASA Astrophysics Data System (ADS)

Al-Homoud, A.

2003-04-01

On March 11, 2002, at mid nigh, the Fujairah Masafi region in the UAE was shaken by an earthquake of shallow depth and local magnitude m = 5.1 on Richter Scale. The earthquake occurred on Dibba fault in the UAE with epicenter of the earthquake at 20 km NW of Fujairha city. The focal depth was just 10 km. The earthquake was felt in most parts of the northern emirates: Dubai, Sharjah, Ajman, Ras Al-Khaima, and Um-Qwain. The "main shock" was followed in the following weeks by more than twenty five earthquakes with local magnitude ranging from m = 4 to m = 4.8. The location of those earthquakes was along Zagros Reverse Faulting System in the Iranian side the Arabian Gulf, opposite to the Shores of the UAE. Most of these earthquakes were shallow too and were actually felt by the people. However, there was another strong earthquake in early April 2002 in the same Masafi region with local magnitude m = 5.1 and focal depth 30 km, therefore it was not felt by the northern emirates residents. No major structural damages to buildings and lifeline systems were reported in the several cities located in the vicinity of the earthquake epicenter. The very small values of ground accelerations were not enough to test the structural integrity of tall building and major infrastructures. Future major earthquakes anticipated in the region in close vicinity of northern emirates, once they occur, and considering the noticeable local site effect of the emirates sandy soils of high water table levels, will surely put these newly constructed building into the real test. Even though there were no casualties in the March 11th event, but there was major fear as a result of the loud sound of rock rupture heard in the mountains close to Maafi, the noticeable disturbance of animals and birds minutes before the earthquake incident and during the incident, cracks in the a good number of Masafi buildings and major damages that occurred in "old" buildings of Fujairah Masafi area, the closest city to

Influence of Reactive Transport on the Reduction of U(VI) in the Presence of Fe(III) and Nitrate: Implications for U(VI) Immobilization by Bioremediation / Biobarriers- Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

B.D. Wood

2007-01-01

Subsurface contamination by metals and radionuclides represent some of the most challenging remediation problems confronting the Department of Energy (DOE) complex. In situ remediation of these contaminants by dissimilatory metal reducing bacteria (DMRB) has been proposed as a potential cost effective remediation strategy. The primary focus of this research is to determine the mechanisms by which the fluxes of electron acceptors, electron donors, and other species can be controlled to maximize the transfer of reductive equivalents to the aqueous and solid phases. The proposed research is unique in the NABIR portfolio in that it focuses on (i) the role ofmore » flow and transport in the initiation of biostimulation and the successful sequestration of metals and radionuclides [specifically U(VI)], (ii) the subsequent reductive capacity and stability of the reduced sediments produced by the biostimulation process, and (iii) the potential for altering the growth of biomass in the subsurface by the addition of specific metabolic uncoupling compounds. A scientifically-based understanding of these phenomena are critical to the ability to design successful bioremediation schemes. The laboratory research will employ Shewanella putrefaciens (CN32), a facultative DMRB that can use Fe(III) oxides as a terminal electron acceptor. Sediment-packed columns will be inoculated with this organism, and the reduction of U(VI) by the DMRB will be stimulated by the addition of a carbon and energy source in the presence of Fe(III). Separate column experiments will be conducted to independently examine: (1) the importance of the abiotic reduction of U(VI) by biogenic Fe(II); (2) the influence of the transport process on Fe(III) reduction and U(VI) immobilization, with emphasis on methods for controlling the fluxes of aqueous species to maximize uranium reduction; (3) the reductive capacity of biologically-reduced sediments (with respect to re-oxidation by convective fluxes of O2 and NO3

Differential determination of chromium(VI) and total chromium in natural waters using flow injection on-line separation and preconcentration electrothermal atomic absorption spectrometry.

PubMed

Sperling, M; Yin, X; Welz, B

1992-03-01

A rapid, sensitive and selective method for the differential determination of CrIII and CrVI in natural waters is described. Chromium(vi) can be determined directly by flow injection on-line sorbent extraction preconcentration coupled with electrothermal atomic absorption spectrometry using sodium diethyldithiocarbamate as the complexing agent and C18 bonded silica reversed-phase sorbent as the column material. Total Cr can be determined after oxidation of CrIII to CrVI by potassium peroxydisulfate. Chromium(III) can be calculated by difference. The optimum conditions for sorbent extraction of CrVI and oxidation of CrIII to CrVI are evaluated. A 12-fold enhancement in sensitivity compared with direct introduction of 40 microliters samples was achieved after preconcentration for 60 s, giving detection limits of 16 ng l-1 for CrVI and 18 ng l-1 for total Cr (based on 3 sigma). Results obtained for sea-water and river water reference materials were all within the certified range for total Cr with a precision of better than 10% relative standard deviation in the range 100-200 ng l-1. The selectivity of the determination of CrVI was evaluated by analysing spiked reference materials in the presence of CrIII, resulting in quantitative recovery of CrVI.

Seismic wave attenuation and velocity dispersion in UAE carbonates

NASA Astrophysics Data System (ADS)

Ogunsami, Abdulwaheed Remi

Interpreting the seismic property of fluids in hydrocarbon reservoirs at low frequency scale has been a cherished goal of petroleum geophysics research for decades. Lately, there has been tremendous interest in understanding attenuation as a result of fluid flow in porous media. Although interesting, the emerging experimental and theoretical information still remain ambiguous and are practically not utilized for reasons not too obscure. Attenuation is frequency dependent and hard to measure in the laboratory at low frequency. This thesis describes and reports the results of an experimental study of low frequency attenuation and velocity dispersion on a selected carbonate reservoir samples in the United Arab Emirates (UAE). For the low frequency measurements, stress-strain method was used to measure the moduli from which the velocity is derived. Attenuation was measured as the phase difference between the applied stress and the strain. For the ultrasonic component, the pulse propagation method was employed. To study the fluid effect especially at reservoir in situ conditions, the measurements were made dry and saturated with liquid butane and brine at differential pressures of up to 5000 psi with pore pressure held constant at 500 psi. Similarly to what has been documented in the literatures for sandstone, attenuation of the bulk compressibility mode dominates the losses in these dry and somewhat partially saturated carbonate samples with butane and brine. Overall, the observed attenuation cannot be simply said to be frequency dependent within this low seismic band. While attenuation seems to be practically constant in the low frequency band for sample 3H, such conclusion cannot be made for sample 7H. For the velocities, significant dispersion is observed and Gassmann generally fails to match the measured velocities. Only the squirt model fairly fits the velocities, but not at all pressures. Although the observed dispersion is larger than Biot's prediction, the fact

1. COMPARISON OF PLANS, SHOWING KONGENSGADE 6 (see photograph VI50 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. COMPARISON OF PLANS, SHOWING KONGENSGADE 6 (see photograph VI-50 50-2 for elevation), KONGENSGADE 8 (see photograph VI-50-3 for elevation), KONGENSGADE 9 (see photograph VI-50-3 for elevation), KONGENSGADE 17 (see photograph VI-50-5 for elevation), KONGENSGADE 56 (see photograph VI-50-8 for elevation), & KONGENSGADE 57 (see photograph VI-50-9 for elevation) - King Street Area Study, Kongensgade 5-18, 36, 37B, 51-58 (Houses), 5-18, 36-37B, 51-58 King Street, Frederiksted, St. Croix, VI

29 CFR 1915.1026 - Chromium (VI).

Code of Federal Regulations, 2010 CFR

2010-07-01

... present from skin or eye contact with chromium (VI), the employer shall provide appropriate personal... clothing and equipment should be laundered or cleaned in a manner that minimizes skin or eye contact with... shall provide change rooms in conformance with 29 CFR 1910.141. Where skin contact with chromium (VI...

Characterization of Amoeba proteus myosin VI immunoanalog.

PubMed

Dominik, Magdalena; Kłopocka, Wanda; Pomorski, Paweł; Kocik, Elzbieta; Redowicz, Maria Jolanta

2005-07-01

Amoeba proteus, the highly motile free-living unicellular organism, has been widely used as a model to study cell motility. However, molecular mechanisms underlying its unique locomotion and intracellular actin-based-only trafficking remain poorly understood. A search for myosin motors responsible for vesicular transport in these giant cells resulted in detection of 130-kDa protein interacting with several polyclonal antibodies against different tail regions of human and chicken myosin VI. This protein was binding to actin in the ATP-dependent manner, and immunoprecipitated with anti-myosin VI antibodies. In order to characterize its possible functions in vivo, its cellular distribution and colocalization with actin filaments and dynamin II during migration and pinocytosis were examined. In migrating amoebae, myosin VI immunoanalog localized to vesicular structures, particularly within the perinuclear and sub-plasma membrane areas, and colocalized with dynamin II immunoanalog and actin filaments. The colocalization was even more evident in pinocytotic cells as proteins concentrated within pinocytotic pseudopodia. Moreover, dynamin II and myosin VI immunoanalogs cosedimented with actin filaments, and were found on the same isolated vesicles. Blocking endogenous myosin VI immunoanalog with anti-myosin VI antibodies inhibited the rate of pseudopodia protrusion (about 19% decrease) and uroidal retraction (about 28% decrease) but did not affect cell morphology and the manner of cell migration. Treatment with anti-human dynamin II antibodies led to changes in directionality of amebae migration and affected the rate of only uroidal translocation (about 30% inhibition). These results indicate that myosin VI immunoanalog is expressed in protist Amoeba proteus and may be involved in vesicle translocation and cell locomotion.

Chemical routes to nanocrystalline and thin-film III-VI and I-III-VI semiconductors

NASA Astrophysics Data System (ADS)

Hollingsworth, Jennifer Ann

1999-11-01

The work encompasses: (1) catalyzed low-temperature, solution-based routes to nano- and microcrystalline III-VI semiconductor powders and (2) spray chemical vapor deposition (spray CVD) of I-III-VI semiconductor thin films. Prior to this work, few, if any, examples existed of chemical catalysis applied to the synthesis of nonmolecular, covalent solids. New crystallization strategies employing catalysts were developed for the regioselective syntheses of orthorhombic InS (beta-InS), the thermodynamic phase, and rhombohedral InS (R-InS), a new, metastable structural isomer. Growth of beta-InS was facilitated by a solvent-suspended, molten-metal flux in a process similar to the SolutionLiquid-Solid (SLS) growth of InP and GaAs fibers and single-crystal whiskers. In contrast, metastable R-InS, having a pseudo-graphitic layered structure, was prepared selectively when the molecular catalyst, benzenethiol, was present in solution and the inorganic "catalyst" (metal flux) was not present. In the absence of any crystal-growth facilitator, metal flux or benzenethiol, amorphous product was obtained under the mild reaction conditions employed (T ≤ 203°C). The inorganic and organic catalysts permitted the regio-selective syntheses of InS and were also successfully applied to the growth of network and layered InxSey compounds, respectively, as well as nanocrystalline In2S3. Extensive microstructural characterization demonstrated that the layered compounds grew as fullerene-like nanostructures and large, colloidal single crystals. Films of the I-III-VI compounds, CuInS2, CuGaS2, and Cu(In,Ga)S 2, were deposited by spray CVD using the known single-source metalorganic precursor, (Ph3P)2CuIn(SEt)4, a new precursor, (Ph3P)2CuGa(SEt)3, and a mixture of the two precursors, respectively. The CulnS2 films exhibited a variety of microstructures from dense and faceted or platelet-like to porous and dendritic. Crystallographic orientations ranged from strongly [112] to strongly [220

Effect of compression rate on ice VI crystal growth using dDAC

NASA Astrophysics Data System (ADS)

Lee, Yun-Hee; Kim, Yong-Jae; Lee, Sooheyong; Cho, Yong Chan; Lee, Geun Woo; Frontier in Extreme Physics Team

It is well known that static and dynamic pressure give different results in many aspects. Understanding of crystal growth under such different pressure condition is one of the crucial issues for the formation of materials in the earth and planets. To figure out the crystal growth under the different pressure condition, we should control compression rate from static to dynamic pressurization. Here, we use a dynamic diamond anvil cell (dDAC) technique to study the effect of compression rate of ice VI crystal growth. Using dDAC with high speed camera, we monitored growth of a single crystal ice VI. A rounded ice crystal with rough surface was selected in the phase boundary of water and ice VI and then, its repetitive growth and melting has been carried out by dynamic operation of the pressure cell. The roughened crystal showed interesting growth transition with compression rate from three dimensional to two dimensional growth as well as faceting process. We will discuss possible mechanism of the growth change by compression rate with diffusion mechanism of water. This research was supported by the Converging Research Center Program through the Ministry of Science, ICT and Future Planning, Korea (NRF-2014M1A7A1A01030128).

Neptunium(V) and neptunium(VI) solubilities in synthetic brines of interest to the Waste Isolation Pilot Plant (WIPP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Novak, C.F.; Nitsche, H.; Silber, H.B.

1996-12-31

The solubility of Np(V) and Np(VI) has been measured in three synthetic Na-K-Mg-Cl brines in the presence of CO{sub 2}(g). Experiments were prepared from oversaturation by adding an excess of NpO{sub 2}{sup +} or NpO{sub 2}{sup 2+} to the brines and allowing the neptunium solids to precipitate. Vessels were maintained in contact with fixed CO{sub 2}(g) partial pressures at constant pH and 24 {+-} 1 C. Dissolved Np(V) concentrations decreased several orders of magnitude within the first 100 days of the experiment, while dissolved Np(VI) concentrations decreased initially but then remained relatively constant for more than 400 days. The solidmore » phases formed in all experiments were identified by X-ray powder diffraction as KNpO{sub 2}CO{sub 3}{center_dot}xH{sub 2}O(s). Steady state concentrations for Np(V) are similar to those observed for Pu(V) in the same brines under the same conditions, where Pu occurs predominantly as Pu(V). Similarly, steady state concentrations for Np(VI), which was not reduced over a two year period, compare well with measured Pu(VI) concentrations in the same brines before the Pu(VI) was reduced to Pu(V).« less

40 CFR Appendix Vi to Part 266 - Stack Plume Rise

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Stack Plume Rise VI Appendix VI to Part 266 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED... FACILITIES Pt. 266, App. VI Appendix VI to Part 266—Stack Plume Rise [Estimated Plume Rise (in Meters) Based...

19 CFR Annex Vi to Part 351 - Countervailing Investigations Timeline

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 3 2010-04-01 2010-04-01 false Countervailing Investigations Timeline VI Annex VI to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex VI Annex VI to Part 351—Countervailing Investigations Timeline ER19MY97.000 ...

19 CFR Annex Vi to Part 351 - Countervailing Investigations Timeline

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 3 2013-04-01 2013-04-01 false Countervailing Investigations Timeline VI Annex VI to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex VI Annex VI to Part 351—Countervailing Investigations Timeline ER19MY97.000 ...

19 CFR Annex Vi to Part 351 - Countervailing Investigations Timeline

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 3 2014-04-01 2014-04-01 false Countervailing Investigations Timeline VI Annex VI to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex VI Annex VI to Part 351—Countervailing Investigations Timeline ER19MY97.000 ...

19 CFR Annex Vi to Part 351 - Countervailing Investigations Timeline

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 3 2012-04-01 2012-04-01 false Countervailing Investigations Timeline VI Annex VI to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex VI Annex VI to Part 351—Countervailing Investigations Timeline ER19MY97.000 ...

19 CFR Annex Vi to Part 351 - Countervailing Investigations Timeline

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 3 2011-04-01 2011-04-01 false Countervailing Investigations Timeline VI Annex VI to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex VI Annex VI to Part 351—Countervailing Investigations Timeline ER19MY97.000 ...

40 CFR Appendix Vi to Part 266 - Stack Plume Rise

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Stack Plume Rise VI Appendix VI to Part 266 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED... FACILITIES Pt. 266, App. VI Appendix VI to Part 266—Stack Plume Rise [Estimated Plume Rise (in Meters) Based...

Decreased endometrial vascularity and receptivity in unexplained recurrent miscarriage patients during midluteal and early pregnancy phases.

PubMed

Tan, Shu-Yin; Hang, Fu; Purvarshi, Gowreesunkur; Li, Min-Qing; Meng, Da-Hua; Huang, Ling-Ling

2015-10-01

To evaluate the predictive value of three-dimensional (3D)-power Doppler sonography on recurrent miscarriage. The study patients were divided into a recurrent miscarriage group (30 cases) and a normal pregnancy group (21 cases). Measurement of endometrial thickness was performed using two-dimensional transvaginal ultrasound in the midluteal phase. The endometrial volume, vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) in midluteal and placenta volume, as well as the VI, FI, and VFI of early pregnancy were measured using Virtual Organ Computer-aided Analysis of 3D-power Doppler ultrasound. Endometrial thickness, endometrial volume, endometrial vascular data, VI, FI, and VFI of the midluteal phase were lower in the recurrent miscarriage group compared with the normal pregnancy group (p < 0.05). Placental volume, VI, and VFI during early pregnancy were lower in the miscarriage group compared with the normal pregnancy group (p < 0.05). There was no significant change in FI between the recurrent miscarriage and control groups during early pregnancy (p > 0.05). The predictive accuracy of endometrial thickness, endometrial volume, VI, FI, and VFI in the midluteal phase, and placenta volume, VI, FI, and VFI in early pregnancy as measured by the receiver operating characteristic curve to predict miscarriage before 12 gestational weeks in participants was 0.681, 0.876, 0.770, 0.720, 0.879, 0.771, 0.907, 0.592, respectively. The 3D-power Doppler ultrasound is a more comprehensive and sensitive method for evaluating endometrial receptivity. Endometrial volume, VI, FI, and VFI in the midluteal phase, as well as VI in early pregnancy, can be considered as predictive factors for recurrent miscarriage. Copyright © 2015. Published by Elsevier B.V.

Simulating adsorption of U(VI) under transient groundwater flow and hydrochemistry: Physical versus chemical nonequilibrium model

USGS Publications Warehouse

Greskowiak, J.; Hay, M.B.; Prommer, H.; Liu, C.; Post, V.E.A.; Ma, R.; Davis, J.A.; Zheng, C.; Zachara, J.M.

2011-01-01

Coupled intragrain diffusional mass transfer and nonlinear surface complexation processes play an important role in the transport behavior of U(VI) in contaminated aquifers. Two alternative model approaches for simulating these coupled processes were analyzed and compared: (1) the physical nonequilibrium approach that explicitly accounts for aqueous speciation and instantaneous surface complexation reactions in the intragrain regions and approximates the diffusive mass exchange between the immobile intragrain pore water and the advective pore water as multirate first-order mass transfer and (2) the chemical nonequilibrium approach that approximates the diffusion-limited intragrain surface complexation reactions by a set of multiple first-order surface complexation reaction kinetics, thereby eliminating the explicit treatment of aqueous speciation in the intragrain pore water. A model comparison has been carried out for column and field scale scenarios, representing the highly transient hydrological and geochemical conditions in the U(VI)-contaminated aquifer at the Hanford 300A site, Washington, USA. It was found that the response of U(VI) mass transfer behavior to hydrogeochemically induced changes in U(VI) adsorption strength was more pronounced in the physical than in the chemical nonequilibrium model. The magnitude of the differences in model behavior depended particularly on the degree of disequilibrium between the advective and immobile phase U(VI) concentrations. While a clear difference in U(VI) transport behavior between the two models was noticeable for the column-scale scenarios, only minor differences were found for the Hanford 300A field scale scenarios, where the model-generated disequilibrium conditions were less pronounced as a result of frequent groundwater flow reversals. Copyright 2011 by the American Geophysical Union.

40 CFR Appendixes Vi-Vii to Part 600 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false [Reserved] VI Appendixes VI-VII to Part 600 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND CARBON-RELATED EXHAUST EMISSIONS OF MOTOR VEHICLES Appendixes VI-VII to Part 600 [Reserved] ...

40 CFR Appendixes Vi-Vii to Part 600 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false [Reserved] VI Appendixes VI-VII to Part 600 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND CARBON-RELATED EXHAUST EMISSIONS OF MOTOR VEHICLES Appendixes VI-VII to Part 600 [Reserved] ...

Controls on the rheological properties of peridotite at a palaeosubduction interface: A transect across the base of the Oman-UAE ophiolite

NASA Astrophysics Data System (ADS)

Ambrose, Tyler K.; Wallis, David; Hansen, Lars N.; Waters, Dave J.; Searle, Michael P.

2018-06-01

Studies of experimentally deformed rocks and small-scale natural shear zones have demonstrated that volumetrically minor phases can control strain localisation by limiting grain growth and promoting grain-size sensitive deformation mechanisms. These small-scale studies are often used to infer a critical role for minor phases in the development of plate boundaries. However, the role of minor phases in strain localisation at an actual plate boundary remains to be tested by direct observation. In order to test the hypothesis that minor phases control strain localisation at plate boundaries, we conducted microstructural analyses of peridotite samples collected along a ∼1 km transect across the base of the Oman-United Arab Emirates (UAE) ophiolite. The base of the ophiolite is marked by the Semail thrust, which represents the now exhumed contact between subducted oceanic crust and the overlying mantle wedge. As such, the base of the ophiolite provides the opportunity to directly examine a former plate boundary. Our results demonstrate that the mean olivine grain size is inversely proportional to the abundance of minor phases (primarily orthopyroxene, as well as clinopyroxene, hornblende, and spinel), consistent with suppression of grain growth by grain-boundary pinning. Our results also reveal that mean olivine grain size is proportional to CPO strength (both of which generally decrease towards the metamorphic sole), suggesting that the fraction of strain produced by different deformation mechanisms varied spatially. Experimentally-derived flow laws indicate that under the inferred deformation conditions, the viscosity of olivine was grain-size sensitive. As such, grain size, and thereby the abundance of minor phases, influenced viscosity during subduction-related deformation along the base of the mantle wedge. We calculate an order of magnitude decrease in the viscosity of olivine towards the base of the ophiolite, which suggests strain was localised near the

Summer aerosol particle mixing in different climate and source regions of the United Arab Emirates (UAE)

NASA Astrophysics Data System (ADS)

Semeniuk, T. A.; Bruintjes, R. T.; Salazar, V.; Breed, D. W.; Jensen, T. L.; Buseck, P. R.

2005-12-01

The high aerosol loadings over the UAE reflect local to regional natural and anthropogenic pollution sources. To understand the impact of the high levels of pollution on both local and global climate systems, aerosol characterization flights in summer 2002 were used to sample major source areas, and to provide information on the interaction of aerosol particles within different geographic regions of the UAE. Atmospheric information and aerosol samples were collected from the marine/oil-industry region, NW coastal industries and cities, Oman Mountain Range, and NE coastal region. Aerosol samples were collected with multi-stage impactors and were analysed later using transmission electron microscopy. All samples are dominated by mineral grains or mineral aggregates in the coarse-mode fraction, and ammonium sulfate droplets in the fine-mode fraction. Differences in the types of mineral grains (different regional desert sources), inorganic salt and soot fractions, and types of internally mixed particles occur between regions. Oil-related industry sites have an abundance of coated and internally mixed particles, including sulfate-coated mineral grains, and mineral aggregates with chloride and sulfate. Cities have slightly elevated soot fractions, and typically have metal oxides. The NE coastal area is characterized by high soot fractions (local shipping) and mixed volatile droplets (regional Asian pollution). Particle populations within the convection zone over the Oman Mountain Range comprise an external mixture of particles from NW and NE sources, with many deliquesced particles. Both land-sea breezes in the NW regions and convection systems in the mountains mix aerosol particles from different local and regional sources, resulting in the formation of abundant internally mixed particles. The interaction between desert dust and anthropogenic pollution, and in particular the formation of mineral aggregates with chloride and sulfate, enhances the coarse-mode fraction and

Lack of Collagen VI Promotes Wound-Induced Hair Growth.

PubMed

Chen, Peiwen; Cescon, Matilde; Bonaldo, Paolo

2015-10-01

Collagen VI is an extracellular matrix molecule that is abundantly expressed in the skin. However, the role of collagen VI in hair follicle growth is unknown. Here, we show that collagen VI is strongly deposited in hair follicles, and is markedly upregulated by skin wounding. Lack of collagen VI in Col6a1(-/-) mice delays hair cycling and growth under physiological conditions, but promotes wound-induced hair regrowth without affecting skin regeneration. Conversely, addition of purified collagen VI rescues the abnormal wound-induced hair regrowth in Col6a1(-/-) mice. Mechanistic studies revealed that the increased wound-induced hair regrowth of Col6a1(-/-) mice is triggered by activation of the Wnt/β-catenin signaling pathway, and is abolished by inhibition of this pathway. These findings highlight the essential relationships between extracellular matrix (ECM) and hair follicle regeneration, and suggest that collagen VI could be a potential therapeutic target for hair loss and other skin-related diseases.

Crystal Growth of II-VI Semiconducting Alloys by Directional Solidification

NASA Technical Reports Server (NTRS)

Lehoczky, Sandor L.; Szofran, Frank R.; Su, Ching-Hua; Cobb, Sharon D.; Scripa, Rosalia A.; Sha, Yi-Gao

1999-01-01

This research study is investigating the effects of a microgravity environment during the crystal growth of selected II-VI semiconducting alloys on their compositional, metallurgical, electrical and optical properties. The on-going work includes both Bridgman-Stockbarger and solvent growth methods, as well as growth in a magnetic field. The materials investigated are II-VI, Hg(1-x)Zn(x)Te, and Hg(1-x)Zn(x)Se, where x is between 0 and 1 inclusive, with particular emphasis on x-values appropriate for infrared detection and imaging in the 5 to 30 micron wavelength region. Wide separation between the liquidus and solidus of the phase diagrams with consequent segregation during solidification and problems associated with the high volatility of one of the components (Hg), make the preparation of homogeneous, high-quality, bulk crystals of the alloys an extremely difficult nearly an impossible task in a gravitational environment. The three-fold objectives of the on-going investigation are as follows: (1) To determine the relative contributions of gravitationally-driven fluid flows to the compositional redistribution observed during the unidirectional crystal growth of selected semiconducting solid solution alloys having large separation between the liquidus and solidus of the constitutional phase diagram; (2) To ascertain the potential role of irregular fluid flows and hydrostatic pressure effects in generation of extended crystal defects and second-phase inclusions in the crystals; and, (3) To obtain a limited amount of "high quality" materials needed for bulk crystal property characterizations and for the fabrication of various device structures needed to establish ultimate material performance limits. The flight portion of the study was to be accomplished by performing growth experiments using the Crystal Growth Furnace (CGF) manifested to fly on various Spacelab missions.

Trigonal Cu2-II-Sn-VI4 (II = Ba, Sr and VI = S, Se) quaternary compounds for earth-abundant photovoltaics.

PubMed

Hong, Feng; Lin, Wenjun; Meng, Weiwei; Yan, Yanfa

2016-02-14

We propose trigonal Cu2-II-Sn-VI4 (II = Ba, Sr and VI = S, Se) quaternary compounds for earth-abundant solar cell applications. Through density functional theory calculations, we show that these compounds exhibit similar electronic and optical properties to kesterite Cu2ZnSnS4 (CZTS): high optical absorption with band gaps suitable for efficient single-junction solar cell applications. However, the trigonal Cu2-II-Sn-VI4 compounds exhibit defect properties more suitable for photovoltaic applications than those of CZTS. In CZTS, the dominant defects are the deep acceptors, Cu substitutions on Zn sites, which cause non-radiative recombination and limit the open-circuit voltages of CZTS solar cells. On the contrary, the dominant defects in trigonal Cu2-II-Sn-VI4 are the shallow acceptors, Cu vacancies, similar to those in CuInSe2. Our results suggest that the trigonal Cu2-II-Sn-VI4 quaternary compounds could be promising candidates for efficient earth-abundant thin-film solar cell and photoeletrochemical water-splitting applications.

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

NASA Astrophysics Data System (ADS)

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.

Real-time observation of morphological transformations in II-VI semiconducting nanobelts via environmental transmission electron microscopy

DOE PAGES

Agarwal, Rahul; Zakharov, Dmitri N.; Krook, Nadia M.; ...

2015-05-01

It has been observed that wurtzite II–VI semiconducting nanobelts transform into single-crystal, periodically branched nanostructures upon heating. The mechanism of this novel transformation has been elucidated by heating II–VI nanobelts in an environmental transmission electron microscope (ETEM) in oxidizing, reducing and inert atmospheres while observing their structural changes with high spatial resolution. The interplay of surface reconstruction of high-energy surfaces of the wurtzite phase and environment-dependent anisotropic chemical etching of certain crystal surfaces in the branching mechanism of nanobelts has been observed. Understanding of structural and chemical transformations of materials via in situ microscopy techniques and their role in designingmore » new nanostructured materials is discussed.« less

Hydrocarbon oxidation by beta-halogenated dioxoruthenium(VI) porphyrin complexes: effect of reduction potential (RuVI/V) and C-H bond-dissociation energy on rate constants.

PubMed

Che, Chi-Ming; Zhang, Jun-Long; Zhang, Rui; Huang, Jie-Sheng; Lai, Tat-Shing; Tsui, Wai-Man; Zhou, Xiang-Ge; Zhou, Zhong-Yuan; Zhu, Nianyong; Chang, Chi Kwong

2005-11-18

beta-Halogenated dioxoruthenium(VI) porphyrin complexes [Ru(VI)(F(28)-tpp)O(2)] [F(28)-tpp=2,3,7,8,12,13, 17,18-octafluoro-5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato(2-)] and [Ru(VI)(beta-Br(8)-tmp)O(2)] [beta-Br(8)-tmp=2,3,7,8,12,13,17,18-octabromo-5,10,15,20- tetrakis(2,4,6-trimethylphenyl)porphyrinato(2-)] were prepared from reactions of [Ru(II)(por)(CO)] [por=porphyrinato(2-)] with m-chloroperoxybenzoic acid in CH(2)Cl(2). Reactions of [Ru(VI)(por)O(2)] with excess PPh(3) in CH(2)Cl(2) gave [Ru(II)(F(20)-tpp)(PPh(3))(2)] [F(20)-tpp=5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato(2-)] and [Ru(II)(F(28)-tpp)(PPh(3))(2)]. The structures of [Ru(II)(por)(CO)(H(2)O)] and [Ru(II)(por)(PPh(3))(2)] (por=F(20)-tpp, F(28)-tpp) were determined by X-ray crystallography, revealing the effect of beta-fluorination of the porphyrin ligand on the coordination of axial ligands to ruthenium atom. The X-ray crystal structure of [Ru(VI)(F(20)-tpp)O(2)] shows a Ru=O bond length of 1.718(3) A. Electrochemical reduction of [Ru(VI)(por)O(2)] (Ru(VI) to Ru(V)) is irreversible or quasi-reversible, with the E(p,c)(Ru(VI/V)) spanning -0.31 to -1.15 V versus Cp(2)Fe(+/0). Kinetic studies were performed for the reactions of various [Ru(VI)(por)O(2)], including [Ru(VI)(F(28)-tpp)O(2)] and [Ru(VI)(beta-Br(8)-tmp)O(2)], with para-substituted styrenes p-X-C(6)H(4)CH=CH(2) (X=H, F, Cl, Me, MeO), cis- and trans-beta-methylstyrene, cyclohexene, norbornene, ethylbenzene, cumene, 9,10-dihydroanthracene, xanthene, and fluorene. The second-order rate constants (k(2)) obtained for the hydrocarbon oxidations by [Ru(VI)(F(28)-tpp)O(2)] are up to 28-fold larger than by [Ru(VI)(F(20)-tpp)O(2)]. Dual-parameter Hammett correlation implies that the styrene oxidation by [Ru(VI)(F(28)-tpp)O(2)] should involve rate-limiting generation of a benzylic radical intermediate, and the spin delocalization effect is more important than the polar effect. The k(2) values for the oxidation of styrene and

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

PubMed

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.

The FUSE Survey of 0 VI in the Galactic Halo

NASA Technical Reports Server (NTRS)

Sonneborn, George; Savage, B. D.; Wakker, B. P.; Sembach, K. R.; Jenkins, E. B.; Moos, H. W.; Shull, J. M.

2003-01-01

This paper summarizes the results of the Far-Ultraviolet Spectroscopic Explorer (FUSE) program to study 0 VI in the Milky Way halo. Spectra of 100 extragalactic objects and two distant halo stars are analyzed to obtain measures of O VI absorption along paths through the Milky Way thick disk/halo. Strong O VI absorption over the velocity range from -100 to 100 km/s reveals a widespread but highly irregular distribution of O VI, implying the existence of substantial amounts of hot gas with T approx. 3 x 10(exp 5) K in the Milky Way thick disk/halo. The overall distribution of O VI is not well described by a symmetrical plane-parallel layer of patchy O VI absorption. The simplest departure from such a model that provides a reasonable fit to the observations is a plane-parallel patchy absorbing layer with an average O VI mid-plane density of n(sub 0)(O VI) = 1.7 x 10(exp -2)/cu cm, a scale height of approx. 2.3 kpc, and a approx. 0.25 dex excess of O VI in the northern Galactic polar region. The distribution of O VI over the sky is poorly correlated with other tracers of gas in the halo, including low and intermediate velocity H I, Ha emission from the warm ionized gas at approx. l0(exp 4) K, and hot X-ray emitting gas at approx. l0(exp 6) K . The O VI has an average velocity dispersion, b approx. 60 km/s and standard deviation of 15 km/s. Thermal broadening alone cannot explain the large observed profile widths. A combination of models involving the radiative cooling of hot fountain gas, the cooling of supernova bubbles in the halo, and the turbulent mixing of warm and hot halo gases is required to explain the presence of O VI and other highly ionized atoms found in the halo. The preferential venting of hot gas from local bubbles and superbubbles into the northern Galactic polar region may explain the enhancement of O VI in the North.

Design, baseline characteristics, and early findings of the MPS VI (mucopolysaccharidosis VI) Clinical Surveillance Program (CSP).

PubMed

Hendriksz, Christian J; Giugliani, Roberto; Harmatz, Paul; Lampe, Christina; Martins, Ana Maria; Pastores, Gregory M; Steiner, Robert D; Leão Teles, Elisa; Valayannopoulos, Vassili

2013-03-01

To outline the design, baseline data, and 5-year follow-up data of patients with mucopolysaccharidosis (MPS) VI enrolled in the Clinical Surveillance Program (CSP), a voluntary, multinational, observational program. The MPS VI CSP was opened in 2005 to collect, for at least 15 years, observational data from standard clinical and laboratory assessments of patients with MPS VI. Baseline and follow-up data are documented by participating physicians in electronic case report forms. Between September 2005 and March 2010 the CSP enrolled 132 patients, including 123 who received enzyme replacement therapy (ERT) with galsulfase. Median age at enrolment was 13 years (range 1-59). Mean baseline data showed impaired growth, hepatosplenomegaly, and reduced endurance and pulmonary function. The most common findings were heart valve disease (90%), reduced visual acuity (79%), impaired hearing (59%), and hepatosplenomegaly (54%). Follow-up data up to 5 years in patients with pre- and post-ERT measurements showed a decrease in urinary glycosaminoglycans and increases in height and weight in patients <16 years and suggested reductions in liver and spleen size and improvements in endurance and pulmonary function after ERT was started. Vision, hearing, and cardiac function were unchanged. Safety data were in line with previous reports. The CSP represents the largest cross-sectional study of MPS VI to date. This first report provides information on the design and implementation of the program and population statistics for several clinical variables in patients with MPS VI. Data collected over 5 years suggest that ERT provides clinical benefit and is well-tolerated with no new safety concerns.

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

PubMed

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.

PubMed

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.

32 CFR 2003.6 - Voting (Article VI).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 6 2014-07-01 2014-07-01 false Voting (Article VI). 2003.6 Section 2003.6 National Defense Other Regulations Relating to National Defense INFORMATION SECURITY OVERSIGHT OFFICE...) BYLAWS, RULES, AND APPEAL PROCEDURES Bylaws § 2003.6 Voting (Article VI). (a) Motions. When the Panel is...

32 CFR 2003.6 - Voting (Article VI).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 6 2013-07-01 2013-07-01 false Voting (Article VI). 2003.6 Section 2003.6 National Defense Other Regulations Relating to National Defense INFORMATION SECURITY OVERSIGHT OFFICE...) BYLAWS, RULES, AND APPEAL PROCEDURES Bylaws § 2003.6 Voting (Article VI). (a) Motions. When the Panel is...

Distribution and Kinematics of O VI in the Galactic Halo

NASA Astrophysics Data System (ADS)

Savage, B. D.; Sembach, K. R.; Wakker, B. P.; Richter, P.; Meade, M.; Jenkins, E. B.; Shull, J. M.; Moos, H. W.; Sonneborn, G.

2003-05-01

Far-Ultraviolet Spectroscopic Explorer (FUSE) spectra of 100 extragalactic objects and two distant halo stars are analyzed to obtain measures of O VI λλ1031.93, 1037.62 absorption along paths through the Milky Way thick disk/halo. Strong O VI absorption over the velocity range from -100 to 100 km s-1 reveals a widespread but highly irregular distribution of O VI, implying the existence of substantial amounts of hot gas with T~3×105 K in the Milky Way thick disk/halo. The integrated column density, log[N(O VI) cm-2], ranges from 13.85 to 14.78 with an average value of 14.38 and a standard deviation of 0.18. Large irregularities in the gas distribution are found to be similar over angular scales extending from <1° to 180°, implying a considerable amount of small- and large-scale structure in the absorbing gas. The overall distribution of O VI is not well described by a symmetrical plane-parallel layer of patchy O VI absorption. The simplest departure from such a model that provides a reasonable fit to the observations is a plane-parallel patchy absorbing layer with an average O VI midplane density of n0(O VI)=1.7×10-8 cm-3, a scale height of ~2.3 kpc, and a ~0.25 dex excess of O VI in the northern Galactic polar region. The distribution of O VI over the sky is poorly correlated with other tracers of gas in the halo, including low- and intermediate-velocity H I, Hα emission from the warm ionized gas at ~104 K, and hot X-ray-emitting gas at ~106 K. The O VI has an average velocity dispersion, b~60 km s-1, and standard deviation of 15 km s-1. Thermal broadening alone cannot explain the large observed profile widths. The average O VI absorption velocities toward high-latitude objects (|b|>45deg) range from -46 to 82 km s-1, with a high-latitude sample average of 0 km s-1 and a standard deviation of 21 km s-1. High positive velocity O VI absorbing wings extending from ~100 to ~250 km s-1 observed along 21 lines of sight may be tracing the flow of O VI into the halo

Degradation of chloramphenicol by potassium ferrate (VI) oxidation: kinetics and products.

PubMed

Zhou, Jia-Heng; Chen, Kai-Bo; Hong, Qian-Kun; Zeng, Fan-Cheng; Wang, Hong-Yu

2017-04-01

The oxidation of chloramphenicol (CAP) by potassium ferrate (VI) in test solution was studied in this paper. A series of jar tests were performed at bench scale with pH of 5-9 and molar ratio [VI/CAP] of 16.3:1-81.6:1. Results showed that raising VI dose could improve the treatment performance and the influence of solution pH was significant. VI is more reactive in neutral conditions, presenting the highest removal efficiency of CAP. The rate law for the oxidation of CAP by VI was first order with respect to each reactant, yielding an overall second-order reaction. Furthermore, five oxidation products were observed during CAP oxidation by VI. Results revealed that VI attacked the amide group of CAP, leading to the cleavage of the group, while benzene ring remained intact.

Aerosol Retrievals Over Land and Water using Deep Blue Algorithm from SeaWiFS and MODIS during UAE2 Field Campaign

NASA Astrophysics Data System (ADS)

Hsu, N.

2005-12-01

The environment in Southwest Asia exhibits one of the most complex situations for aerosol remote sensing from space. Several air masses with different aerosol characteristics commonly converge in this region. In particular, there are often fine mode pollution particles generated from oil industry activities in the Persian Gulf colliding with coarse mode dust particles lifted from desert sources in the surrounding areas. During the course of the UAE field campaign (August-October, 2004), we provided near-real time information, calculated using the Deep Blue algorithm, of satellite aerosol optical thickness and Angstrom exponent over the Southwest Asia region, including the Arabian Peninsula, Iran, Afghanistan, Pakistan, and part of north Africa. In this paper, we will present results of aerosol characteristics retrieved from SeaWiFS and MODIS over the Arabian Peninsula, Persian Gulf, and the Arabian Sea during the UAE experiment. The spectral surface reflectance data base constructed using satellite reflectance from MODIS and SeaWiFS employed in our algorithm will be discussed. We will also compare the resulting satellite retrieved aerosol optical thickness and Angstrom exponent with those obtained from the ground based sun photometers from AERONET in the region. Finally, we will discuss the changes in shortwave and longwave fluxes at the top of atmosphere in response to changes in aerosol optical thickness (i.e. aerosol forcing).

Stabilization of Cr(VI) from fine ferrochrome dust using exfoliated vermiculite.

PubMed

Mulange Wa Mulange, Delphin; Garbers-Craig, Andrie Mariana

2012-07-15

This study proved that vermiculite, a natural occurring mineral, can effectively remove and stabilize Cr(VI) from fine ferrochrome dust leachate. Batch adsorption studies were carried out to determine the effect of pH, contact time and adsorbent dose on the removal of Cr(VI). The process was found to be highly pH dependent. The optimum conditions for the Cr(VI) removal are at a pH of 1.5, contact time of 2h and adsorbent dose of 10gL(-1). The stability of the Cr(VI)-loaded vermiculite remained unchanged after 12 months, when the vermiculite was evaluated with the ASTM and TCLP Cr(VI) leach methods. However, Cr(VI) desorption did take place when the Acid Rain Test was used. The adsorption kinetic data fits the pseudo-second order model, while the equilibrium data of Cr(VI) adsorption onto vermiculite are best described by the Langmuir isotherm. The presence of hydrobiotite and biotite in the industrial vermiculite slightly decreased the degree of adsorption of Cr(VI). Copyright © 2012 Elsevier B.V. All rights reserved.

An approach to compute the C factor for universal soil loss equation using EOS-MODIS vegetation index (VI)

NASA Astrophysics Data System (ADS)

Li, Hui; He, Huizhong; Chen, Xiaoling; Zhang, Lihua

2008-12-01

C factor, known as cover and management factor in USLE, is one of the most important factors since it represents the combined effects of plant, soil cover and management on erosion, whereas it also most easily changed variables by men for it itself is time-variant and the uncertainty nature. So it's vital to compute C factor properly in order to model erosion effectively. In this paper we attempt to present a new method for calculating C value using Vegetation Index (VI) derived from multi-temporal MODIS imagery, which can estimate C factor in a more scientific way. Based on the theory that C factor is strongly correlated with VI, the average annual C value is estimated by adding the VI value of three growth phases within a year with different weights. Modified Fournier Index (MFI) is employed to determine the weight of each growth phase for the vegetation growth and agricultural activities are significantly influenced by precipitation. The C values generated by the proposed method were compared with that of other method, and the results showed that the results of our method is highly correlated with the others. This study is helpful to extract C value from satellite data in a scientific and efficient way, which in turn could be used to facilitate the prediction of erosion.

Cr(VI) transport via a supported ionic liquid membrane containing CYPHOS IL101 as carrier: system analysis and optimization through experimental design strategies.

PubMed

Rodríguez de San Miguel, Eduardo; Vital, Xóchitl; de Gyves, Josefina

2014-05-30

Chromium(VI) transport through a supported liquid membrane (SLM) system containing the commercial ionic liquid CYPHOS IL101 as carrier was studied. A reducing stripping phase was used as a mean to increase recovery and to simultaneously transform Cr(VI) into a less toxic residue for disposal or reuse. General functions which describe the time-depending evolution of the metal fractions in the cell compartments were defined and used in data evaluation. An experimental design strategy, using factorial and central-composite design matrices, was applied to assess the influence of the extractant, NaOH and citrate concentrations in the different phases, while a desirability function scheme allowed the synchronized optimization of depletion and recovery of the analyte. The mechanism for chromium permeation was analyzed and discussed to contribute to the understanding of the transfer process. The influence of metal concentration was evaluated as well. The presence of different interfering ions (Ca(2+), Al(3+), NO3(-), SO4(2-), and Cl(-)) at several Cr(VI): interfering ion ratios was studied through the use of a Plackett and Burman experimental design matrix. Under optimized conditions 90% of recovery was obtained from a feed solution containing 7mgL(-1) of Cr(VI) in 0.01moldm(-3) HCl medium after 5h of pertraction. Copyright © 2014 Elsevier B.V. All rights reserved.

Cranial nerve VI palsy after dural-arachnoid puncture.

PubMed

Hofer, Jennifer E; Scavone, Barbara M

2015-03-01

In this article, we provide a literature review of cranial nerve (CN) VI injury after dural-arachnoid puncture. CN VI injury is rare and ranges in severity from diplopia to complete lateral rectus palsy with deviated gaze. The proposed mechanism of injury is cerebrospinal fluid leakage causing intracranial hypotension and downward displacement of the brainstem. This results in traction on CN VI leading to stretch and neural demyelination. Symptoms may present 1 day to 3 weeks after dural-arachnoid puncture and typically are associated with a postdural puncture (spinal) headache. Resolution of symptoms may take weeks to months. Use of small-gauge, noncutting spinal needles may decrease the risk of intracranial hypotension and subsequent CN VI injury. When ocular symptoms are present, early administration of an epidural blood patch may decrease morbidity or prevent progression of ocular symptoms.

Surface catalysis of uranium(VI) reduction by iron(II)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liger, E.; Charlet, L.; Van Cappellen, P.

1999-10-01

concentration of adsorbed uranyl. The pseudo-first-order rate constant varies with pH (range, 6--7.5) and the total (dissolved + adsorbed) concentration of Fe(II) (range, 2--160 {micro}M). When analyzing the rate data in terms of the calculated surface speciation, the variability of the rate constant can be accounted for entirely by changes in the concentration of the Fe(II) monohydroxo surface complex {equivalent{underscore}to}Fe{sup III}OFe{sup II}OH{sup 0}. Therefore, the rate law is derived for the hematite-catalyzed reduction of uranyl by Fe(II), where the bimolecular rate constant {kappa} has a value of 399 {+-} 25 M{sup {minus}1} min{sup {minus}1} at 25 C. The hydroxo surface complex is the rate-controlling reductant species, because it provides the most favorable coordination environment in which electrons are removed from Fe(II). Natural particulate matter collected in the hypolimnion of a seasonally stratified lake also causes the rapid reduction of uranyl by Fe(II), Ferrihydrite, identified in the particulate matter by X-ray diffraction, is one possible mineral phase accelerating the reaction between U(VI) and Fe(II). At near-neutral pH and total Fe(II) levels less than 1 mM, the pseudo-first-order rate constants of chemical U(VI) reduction, measured in the presence of the hematite and lake particles, are of the same order of magnitude as the highest corresponding rate coefficients for enzymatic U(VI) reduction in bacterial cultures. Hence, based on the results of this study, surface-catalyzed U(VI) reduction by Fe(II) is expected to be a major pathway of uranium immobilization in a wide range of redox-stratified environments.« less

In situ observations of a high-pressure phase of H2O ice

USGS Publications Warehouse

Chou, I.-Ming; Blank, J.G.; Goncharov, A.F.; Mao, Ho-kwang; Hemley, R.J.

1998-01-01

A previously unknown solid phase of H2O has been identified by its peculiar growth patterns, distinct pressure-temperature melting relations, and vibrational Raman spectra. Morphologies of ice crystals and their pressure-temperature melting relations were directly observed in a hydrothermal diamond-anvil cell for H2O bulk densities between 1203 and 1257 kilograms per cubic meter at temperatures between -10??and 50??C. Under these conditions, four different ice forms were observed to melt: two stable phases, ice V and ice VI, and two metastable phases, ice IV and the new ice phase. The Raman spectra and crystal morphology are consistent with a disordered anisotropic structure with some similarities to ice VI.

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

PubMed

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.

Forensic investigation of a chromium(VI) groundwater plume in Thiva, Greece.

PubMed

Panagiotakis, I; Dermatas, D; Vatseris, C; Chrysochoou, M; Papassiopi, N; Xenidis, A; Vaxevanidou, K

2015-01-08

A forensic investigation was conducted with the aim of decoupling the contribution of geogenic and anthropogenic Cr(VI) sources in the wider area of Thiva. Groundwater and topsoil samples were collected from two Cr(VI) groundwater plumes of 160 μg/L and 75 μg/L. A series of evidence support the view that the origin of Cr(VI) detected in groundwater is mainly geogenic. These are: (a) the presence of Cr in topsoil of the wider area, (b) the moderate Cr(VI) groundwater concentrations, (c) the high Ni levels within the Cr(VI) plumes, (d) the predominance of Mn(IV), which is a prerequisite for Cr(III) oxidation to Cr(VI), and (e) the absence of co-contaminants. The present study also revealed that, although both Cr(VI) plumes are clearly of geogenic origin, the plume with the elevated Cr(VI) values, in the north of Thiva town, exhibits also an anthropogenic component, which can potentially be attributed to the alkaline environment associated with the old uncontrolled landfill of Thiva and the industrial cluster located in this area. Copyright © 2014 Elsevier B.V. All rights reserved.

Singular Instantons and Painlevé VI

NASA Astrophysics Data System (ADS)

Muñiz Manasliski, Richard

2016-06-01

We consider a two parameter family of instantons, which is studied in [Sadun L., Comm. Math. Phys. 163 (1994), 257-291], invariant under the irreducible action of SU_2 on S^4, but which are not globally defined. We will see that these instantons produce solutions to a one parameter family of Painlevé VI equations (P_VI}) and we will give an explicit expression of the map between instantons and solutions to P_{VI}. The solutions are algebraic only for that values of the parameters which correspond to the instantons that can be extended to all of S^4. This work is a generalization of [Muñiz Manasliski R., Contemp. Math., Vol. 434, Amer. Math. Soc., Providence, RI, 2007, 215-222] and [Muñiz Manasliski R., J. Geom. Phys. 59 (2009), 1036-1047, arXiv:1602.07221], where instantons without singularities are studied.

Formic acid interaction with the uranyl(VI) ion: structural and photochemical characterization.

PubMed

Lucks, Christian; Rossberg, André; Tsushima, Satoru; Foerstendorf, Harald; Fahmy, Karim; Bernhard, Gert

2013-10-07

Complex formation between the uranyl(VI) ion and formic acid was studied by infrared absorption (IR) and X-ray absorption (EXAFS) spectroscopy as well as density functional theory (DFT) calculations. In contrast to the acetate ion which forms exclusively a bidentate complex with uranyl(VI), the formate ion binds to uranyl(VI) in a unidentate fashion. The photochemistry of the uranyl(VI)-formic acid system was explored by DFT calculations and photoreduction of uranyl(VI) in the presence of formic acid was found to occur via an intermolecular process, that is, hydrogen abstraction from hydrogenformate by the photo-excited uranyl(VI). There is no photo-induced decarboxylation of uranyl(VI) formate via an intramolecular process, presumably due to lack of a C=C double bond.

U(VI) adsorption on aquifer sediments at the Hanford Site.

PubMed

Um, Wooyong; Serne, R Jeffrey; Brown, Christopher F; Last, George V

2007-08-15

Aquifer sediments collected via split-spoon sampling in two new groundwater wells in the 200-UP-1 operable unit at the Hanford Site were characterized and showed typical Ringold Unit E Formation properties dominated by gravel and sand. High iron-oxide content in Fe oxide/clay coatings caused the highest U(VI) adsorption as quantified by batch K(d) values, indicating iron oxides are the key solid adsorbent in the 200-UP-1 sediments that affect U(VI) fate and mobility. Even though U(VI) adsorption on the gravel-sized fraction of the sediments is considered to be negligible, careful characterization should be conducted to determine U(VI) adsorption on gravel, because of presence of Fe oxides coatings and diffusion-controlled adsorption into the gravel particles' interior surfaces. A linear adsorption isotherm was observed up to 10(-6) M (238 microg/L) of total U(VI) concentration in batch U(VI) adsorption tests with varying total U(VI) concentrations in spiked groundwater. U(VI) adsorption decreased with increasing concentrations of dissolved carbonate, because strong anionic aqueous uranium-carbonate complexes formed at high pH and high alkalinity conditions. Noticeable uranium desorption hysteresis was observed in a flow-through column experiment, suggesting that desorption K(d) values for aged uranium-contaminated sediments at the Hanford Site can be larger than adsorption K(d) values determined in short-term laboratory experiments and slow uranium release from contaminated sediments into the groundwater is expected.

Remediation of Cr(VI)-Contaminated Soil Using the Acidified Hydrazine Hydrate.

PubMed

Ma, Yameng; Li, Fangfang; Jiang, Yuling; Yang, Weihua; Lv, Lv; Xue, Haotian; Wang, Yangyang

2016-09-01

Acidified hydrazine hydrate was used to remediate Cr(VI)-contaminated soil. The content of water-soluble Cr(VI) in contaminated soil was 4977.53 mg/kg. The optimal initial pH of hydrazine hydrate solution, soil to solution ratio and molar ratio of Cr(VI) to hydrazine hydrate for remediation of Cr(VI)-contaminated soil were 5.0, 3:1 and 1:3, respectively. Over 99.50 % of water-soluble Cr(VI) in the contaminated soil was reduced at the optimal condition within 30 min. The remediated soil can keep stable within 4 months. Meanwhile the total phosphorus increased from 0.47 to 4.29 g/kg, indicating that using of acidified hydrazine hydrate is an effective method to remediate Cr(VI)-contaminated soil.

Detection and Persistence of Vi Antigen in Tissues of Actively Immunized Mice1

PubMed Central

Gaines, Sidney; Currie, Julius A.; Tully, Joseph G.

1965-01-01

Gaines, Sidney (Walter Reed Army Institute of Research, Washington, D.C.), Julius A. Currie, and Joseph G. Tully. Detection and persistence of Vi antigen in tissues of actively immunized mice. J. Bacteriol. 89:776–781. 1965.—The presence, distribution, and persistence of Vi antigen in mouse tissue was determined by means of active immunization tests with tissue extracts. Mice were injected intraperitoneally with purified Vi antigen or Vi-containing bacilli. At appropriate intervals, animals were killed, and saline extracts of their tissues were prepared. Mice were immunized with these extracts and challenged 6 days later with 10 ld50 of Salmonella typhosa Ty2. Protection was afforded by tissue extracts from Vi-injected mice, but not by normal tissue extracts. That the immunizing capacity of tissue extracts from Vi-injected mice was attributable to Vi antigen was affirmed by the demonstration that these extracts stimulated the production of Vi antibody in mice, coated erythrocytes for agglutination by Vi antiserum, and inhibited agglutination of Vi-sensitized red blood cells by known Vi antisera. Vi antigen could be detected in the liver and spleen of mice injected with as little as 1 μg. In mice given 150 μg, the antigen was still present in liver tissue 231 days later. PMID:14273660

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

PubMed

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.

PubMed

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.

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

PubMed Central

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

2014-01-01

Background 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. Methods 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. Results Both methods predicted a similar range of a minimum protective level of anti-Vi IgG between 1.4 and 2.0 μg/ml (short term threshold). When applying a protective threshold of 10 μg/ml at 6 months post immunization, an IgG level in excess of 1.4 μg/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 > 10 μg/ml (long term threshold) 6 months after immunization may reflect the proportion protected over at least a 4 year period. Conclusion The current assignment of an anti-Vi IgG protective level may be of value when evaluating vaccine performance of future Vi conjugate vaccines. PMID:24630869

Fat ViP MRI: Virtual Phantom Magnetic Resonance Imaging of water-fat systems.

PubMed

Salvati, Roberto; Hitti, Eric; Bellanger, Jean-Jacques; Saint-Jalmes, Hervé; Gambarota, Giulio

2016-06-01

Virtual Phantom Magnetic Resonance Imaging (ViP MRI) is a method to generate reference signals on MR images, using external radiofrequency (RF) signals. The aim of this study was to assess the feasibility of ViP MRI to generate complex-data images of phantoms mimicking water-fat systems. Various numerical phantoms with a given fat fraction, T2* and field map were designed. The k-space of numerical phantoms was converted into RF signals to generate virtual phantoms. MRI experiments were performed at 4.7T using a multi-gradient-echo sequence on virtual and physical phantoms. The data acquisition of virtual and physical phantoms was simultaneous. Decomposition of the water and fat signals was performed using a complex-based water-fat separation algorithm. Overall, a good agreement was observed between the fat fraction, T2* and phase map values of the virtual and numerical phantoms. In particular, fat fractions of 10.5±0.1 (vs 10% of the numerical phantom), 20.3±0.1 (vs 20%) and 30.4±0.1 (vs 30%) were obtained in virtual phantoms. The ViP MRI method allows for generating imaging phantoms that i) mimic water-fat systems and ii) can be analyzed with water-fat separation algorithms based on complex data. Copyright © 2016 Elsevier Inc. All rights reserved.

Cr(VI) Sorption by Nanosized FeS-Coated Sand

NASA Astrophysics Data System (ADS)

Park, M.; Jeong, H. Y.; Lee, S.; Kang, N.; Kim, K. H.; Choi, H. J.

2015-12-01

Cr(VI) sorption experiments were conducted as a function of pH (4.7, 7.0 and 9.7) using nanosized FeS-coated sand under anoxic environments. Under the experimental conditions, the sand used, with the FeS content of 0.068 mmol per 1 g sand, completely reduced the initially added Cr(VI) to Cr(III) over the pH range examined. The sorption of the once-reduced Cr(III) varied greatly with the solution pH. By the solution-phase analysis, significant amounts of Cr(III) remained as dissolved species at pH 4.7. On the other hands, dissolved Cr was below the detection limit (0.2 μM) at pH 7.0 and 9.7, indicating the greater sorption of Cr(III) at neutral to basic pH than acidic pH. From Cr-K edge X-ray absorption spectroscopy (XAS) analysis of the solid products, the sorbed Cr was shown to be present predominantly as trivalent state in all samples. Regardless of pH, the second coordination shell around Cr (i.e., the Cr-Cr(Fe) shell) was shown to be located at ~2.6 Å, which was far shorter than those in Cr(III)-bearing model compounds such as Cr(OH)3(s) and [Cr, Fe](OH)3(s). Furthermore, the coordination numbers of the second and third shells in the sorption samples (N = 0.7-1.8) were much lower than those in Cr(OH)3(s) and [Cr, Fe](OH)3(s). Taken together, the sorption of the once-reduced Cr(III) was likely to occur via surface-mediated processes (e.g., surface complexation and/or surface precipitation) rather than the bulk-phase precipitation. Financial support was provided by the "R&D Project on Environmental Management of Geologic CO2 Storage" from the KEITI (Project Number: 2014001810003).

Restaurant-associated outbreak of typhoid fever in Maryland: identification of carrier facilitated by measurement of serum Vi antibodies.

PubMed Central

Lin, F Y; Becke, J M; Groves, C; Lim, B P; Israel, E; Becker, E F; Helfrich, R M; Swetter, D S; Cramton, T; Robbins, J B

1988-01-01

Ten cases of typhoid fever occurred between 24 August and 1 September 1986 in the vicinity of Silver Spring, Md. Shrimp salad served in a fast-food restaurant was implicated as the source of infection. Stool cultures were obtained from 104 employees, and serum Vi antibodies were assayed in 97 of the employees. Salmonella typhi was isolated from stool cultures of an 18-year-old asymptomatic female employee, who was a food handler. A high level of Vi antibodies (79.0 micrograms/ml), measured by radioimmunoassay, was found in her serum. She had emigrated from an endemic area at the age of 14 years and had visited that endemic area 2 years previously. The causal relation between the carrier and the 10 cases of typhoid fever was confirmed by a common bacteriophage type, denoted "degraded Vi resembling O," in the S. typhi isolates. This phage type is rare in the western hemisphere but common in the endemic area from which the carrier had emigrated. The high level of Vi antibody in the asymptomatic carrier, in contrast to the lower levels in the convalescent- and postimmunization-phase sera, facilitated the identification of the source infection in this outbreak. This radioimmunoassay offers a rapid and standardized method for identifying carriers of S. typhi. PMID:3384930

U(VI) Reduction by Biogenic and Abiotic Hydroxycarbonate Green Rusts: Impacts on U(IV) Speciation and Stability Over Time

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Sen; Boyanov, Maxim I.; Mishra, Bhoopesh

Green rusts (GRs) are redox active Fe II-Fe III minerals that form in the environment via various biotic and abiotic processes. Although both biogenic (BioGR) and abiotic (ChemGR) GRs have been shown to reduce U VI, the dynamics of the transformations and the speciation and stability of the resulting U IV phases are poorly understood. We used carbonate extraction and XAFS spectroscopy to investigate the products of U VI reduction by BioGR and ChemGR. The results show that both GRs can rapidly remove U VI from synthetic groundwater via reduction to U IV. The initial products in the ChemGR systemmore » are solids-associated U IV-carbonate complexes that gradually transform to nanocrystalline uraninite over time, leading to a decrease in the proportion of carbonate-extractable U from ~95% to ~10%. In contrast, solid-phase U IV atoms in the BioGR system remain relatively extractable, non-uraninite U IV species over the same reaction period. The presence of calcium and carbonate in groundwater significantly increase the extractability of U IV in the BioGR system. Furthermore, these data provide new insights into the transformations of U under anoxic conditions in groundwater that contains calcium and carbonate, and have major implications for predicting uranium stability within redox dynamic environments and designing approaches for the remediation of uranium-contaminated groundwater.« less

U(VI) Reduction by Biogenic and Abiotic Hydroxycarbonate Green Rusts: Impacts on U(IV) Speciation and Stability Over Time

DOE PAGES

Yan, Sen; Boyanov, Maxim I.; Mishra, Bhoopesh; ...

2018-04-09

Green rusts (GRs) are redox active Fe II-Fe III minerals that form in the environment via various biotic and abiotic processes. Although both biogenic (BioGR) and abiotic (ChemGR) GRs have been shown to reduce U VI, the dynamics of the transformations and the speciation and stability of the resulting U IV phases are poorly understood. We used carbonate extraction and XAFS spectroscopy to investigate the products of U VI reduction by BioGR and ChemGR. The results show that both GRs can rapidly remove U VI from synthetic groundwater via reduction to U IV. The initial products in the ChemGR systemmore » are solids-associated U IV-carbonate complexes that gradually transform to nanocrystalline uraninite over time, leading to a decrease in the proportion of carbonate-extractable U from ~95% to ~10%. In contrast, solid-phase U IV atoms in the BioGR system remain relatively extractable, non-uraninite U IV species over the same reaction period. The presence of calcium and carbonate in groundwater significantly increase the extractability of U IV in the BioGR system. Furthermore, these data provide new insights into the transformations of U under anoxic conditions in groundwater that contains calcium and carbonate, and have major implications for predicting uranium stability within redox dynamic environments and designing approaches for the remediation of uranium-contaminated groundwater.« less

Oxidation of Oil Sands Process-Affected Water by Potassium Ferrate(VI).

PubMed

Wang, Chengjin; Klamerth, Nikolaus; Huang, Rongfu; Elnakar, Haitham; Gamal El-Din, Mohamed

2016-04-19

This paper investigates the oxidation of oil sands process-affected water (OSPW) by potassium ferrate(VI). Due to the selectivity of ferrate(VI) oxidation, two-ring and three-ring fluorescing aromatics were preferentially removed at doses <100 mg/L Fe(VI), and one-ring aromatics were removed only at doses ≥100 mg/L Fe(VI). Ferrate(VI) oxidation achieved 64.0% and 78.4% removal of naphthenic acids (NAs) at the dose of 200 mg/L and 400 mg/L Fe(VI) respectively, and NAs with high carbon number and ring number were removed preferentially. (1)H nuclear magnetic resonance ((1)H NMR) spectra indicated that the oxidation of fluorescing aromatics resulted in the opening of some aromatic rings. Electron paramagnetic resonance (EPR) analysis detected signals of organic radical intermediates, indicating that one-electron transfer is one of the probable mechanisms in the oxidation of NAs. The inhibition effect of OSPW on Vibrio fischeri and the toxicity effect on goldfish primary kidney macrophages (PKMs) were both reduced after ferrate(VI) oxidation. The fluorescing aromatics in OSPW were proposed to be an important contributor to this acute toxicity. Degradation of model compounds with ferrate(VI) was also investigated and the results confirmed our findings in OSPW study.

Effective treatment of alkaline Cr(VI) contaminated leachate using a novel Pd-bionanocatalyst: Impact of electron donor and aqueous geochemistry

PubMed Central

Watts, Mathew P.; Coker, Victoria S.; Parry, Stephen A.; Thomas, Russell A.P.; Kalin, Robert; Lloyd, Jonathan R.

2015-01-01

Palladium catalysts offer the potential for the effective treatment of a variety of priority reducible pollutants in natural waters. In this study, microbially synthesized magnetite nanoparticles were functionalized with Pd(0), creating a highly reactive, magnetically recoverable, nano-scale catalyst (Pd-BnM). This was then investigated for the treatment of model Cr(VI) contaminated solutions at a range of pH values, and also alkaline Cr(VI) contaminated leachates from chromite ore processing residue (COPR); a contaminant issue of global concern. The sample of COPR used in this study was obtained from a site in Glasgow, UK, where extensive Cr(VI) contamination has been reported. In initial experiments Pd-BnM was supplied with H2 gas or formate as electron donors, and Cr(VI) removal from model synthetic solutions was quantified at various pH values (2–12). Effective removal was noted at neutral to environmentally relevant alkaline (pH 12) pH values, while the use of formate as an electron donor resulted in loss of performance under acidic conditions (pH 2). Reaction kinetics were then assessed with increasing Pd-BnM loading in both model pH 12 Cr(VI) solutions and the COPR leachate. When formate was used as the electron donor for Pd-BnM, to treat COPR leachate, there was significant inhibition of Cr(VI) removal. In contrast, a promotion of reaction rate, was observed when H2 was employed. Upon sustained reaction with model Cr(VI) solutions, in the presence of excess electron donor (formate or H2), appreciable quantities of Cr(VI) were removed before eventual inactivation of the catalyst. Faster onset of inactivation was reported in the COPR leachates, removing 4% and 64% of Cr(VI) observed from model Cr(VI) solutions, when formate and H2 were used as electron donors, respectively. XAS, TEM-EDX and XPS analysis of the catalysts that had been inactivated in the model solution, showed that the surface had an extensive covering of reduced Cr(III), most likely as a Cr

Sorption characteristic of uranium(VI) ion onto K-feldspar.

PubMed

Gao, Xiaoqing; Bi, Mingliang; Shi, Keliang; Chai, Zhifang; Wu, Wangsuo

2017-10-01

The effect of pH, contact time, temperature, ionic strength and initial U(VI) concentration on U(VI) sorption onto K-feldspar was investigated using batch techniques. The sorption kinetics was evaluated and the activation energy was obtained based on the rate constants at different temperature. Graphical correlations of sorption isotherm models have been evaluated and applied for U(VI) uptake by K-feldspar. Various thermodynamic parameters, such as, Gibb's free energy, entropy and enthalpy of the on-going sorption process have been calculated and the possible sorption mechanism of U(VI) was deduced. The results are expected to help better understand the migration of uranium in the host materials of granite. Copyright © 2017 Elsevier Ltd. All rights reserved.

76 FR 62148 - Title VI; Proposed Circular, Environmental Justice; Proposed Circular

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-06

...-0055] Title VI; Proposed Circular, Environmental Justice; Proposed Circular AGENCY: Federal Transit... the September 29, 2011, Federal Register Notices titled ``Title VI; Proposed Circular'' and... September 29, 2011, Federal Register Notices titled ``Title VI; Proposed Circular'' (76 FR 60593) and...

Ferrate(VI) oxidation of weak-acid dissociable cyanides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ria A. Yngard; Virender K. Sharma; Jan Filip

2008-04-15

Cyanide is commonly found in electroplating, mining, coal gasification, and petroleum refining effluents, which require treatment before being discharged. Cyanide in effluents exists either as free cyanide or as a metal complex. The kinetics of the oxidation of weak-acid dissociable cyanides by an environmentally friendly oxidant, ferrate, were studied as a function of pH (9.1-10.5) and temperature (15-45{sup o}C) using a stopped-flow technique. The weak-acid dissociable cyanides were Cd(CN){sub 4}{sup 2-} and Ni(CN){sub 4}{sup 2-}, and the rate-laws for the oxidation may be -d(Fe(VI))/dt = k (Fe(VI))(M(CN){sub 4}{sup 2-}){sup n} where n = 0.5 and 1 for Cd(CN){sub 4}{sup 2-}more » and Ni(CN){sub 4}{sup 2-}, respectively. The rates decreased with increasing pH and were mostly related to a decrease in concentration of the reactive protonated Fe(VI) species, HFeO{sub 4}{sup -}. The stoichiometries with Fe(VI) were determined to be: 4HFeO{sub 4}{sup -} + M(CN){sub 4}{sup 2-} + 6H{sub 2}O {yields} 4Fe(OH){sub 3} + M{sup 2+} + 4NCO{sup -} + O{sub 2} + 4OH{sup -}. Mechanisms are proposed that agree with the observed reaction rate-laws and stoichiometries of the oxidation of weak-acid dissociable cyanides by Fe(VI). Results indicate that Fe(VI) is effective in removing cyanide in coke oven plant effluent, where organics are also present. 27 refs., 3 figs., 2 tabs.« less

The MK VI - A second generation attitude control system

NASA Astrophysics Data System (ADS)

Meredith, P. J.

1986-10-01

The MK VI, a new multipurpose attitude control system for the exoatmospheric attitude control of sounding rocket payloads, is described. The system employs reprogrammable microcomputer memory for storage of basic control logic and for specific mission event control data. The paper includes descriptions of MK VI specifications and configuration; sensor characteristics; the electronic, analog, and digital sections; the pneumatic system; ground equipment; the system operation; and software. A review of the MK VI performance for the Comet Halley flight is presented. Block diagrams are included.

Kandinsky's "Composition VI": Heideggerian Poetry in Noah's Ark

ERIC Educational Resources Information Center

Hall, Joshua M.

2012-01-01

The author will begin his investigation of Wassily Kandinsky's painting "Composition VI" with Kandinsky's own commentary on the painting. He will then turn to the analysis of Kandinsky and the "Compositions" in John Sallis's book "Shades." Using this analysis as his point of departure, the author will consider how "Composition VI" resonates with…

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

PubMed

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.

Removal of chromium (VI) from aqueous solution using walnut hull.

PubMed

Wang, Xue Song; Li, Zhi Zhong; Tao, Sheng Rong

2009-02-01

In this study, removal of chromium (VI) from aqueous solution by walnut hull (a local low-cost adsorbent) was studied. The extent of adsorption was investigated as a function of solution pH, contact time, adsorbent and adsorbate concentration, reaction temperature and supporting electrolyte (sodium chloride). The Cr (VI) removal was pH-dependent, reaching a maximum (97.3%) at pH 1.0. The kinetic experimental data were fitted to the first-order, modified Freundlich, intraparticle diffusion and Elovich models and the corresponding parameters were obtained. A 102.78 kJ/mol Ea (activation energy) for the reaction of chromium (VI) adsorption onto walnut indicated that the rate-limiting step in this case might be a chemically controlled process. Both the Langmuir and Freundlich isotherms were suitable for describing the biosorption of chromium (VI) onto walnut hull. The uptake of chromium (VI) per weight of adsorbent increased with increasing initial chromium (VI) concentration up to 240-480 mg/L, and decreased sharply with increasing adsorbent concentration ranging from 1.0 to 5.0 g/L. An increase in sodium chloride (as supporting electrolyte) concentration was found to induce a negative effect while an increase in temperature was found to give rise to a positive effect on the chromium (VI) adsorption process. Compared to the various other adsorbents reported in the literature, the walnut hull in this study shows very good promise for practical applicability.

Kinetic evaluation of chromium(VI) sorption by water lettuce (Pistia).

PubMed

Chakraborty, Rupa; Karmakar, Sukalpa; Mukherjee, Somnath; Kumar, Sunil

2014-01-01

An investigation was performed to evaluate the uptake capacity of Pistia in living condition for adsorptive removal of chromium(VI) from spiked solution for examining a remedial measure for disposal of chrome-laden wastewater in an urban wetland system. Kinetics results show about 78% removal was achieved for 3 mg/L initial concentration of Cr(VI). Experimental data showed that the root portion absorbed more Cr(VI) (28.54 μg/g) compared to accumulation in leaf (5.73 μg/g). It was also noted that the plant could effectively remove Cr(VI) from the solution with minor damage up to an initial Cr(VI) concentration of 3 mg/L, for which the adsorption isotherm studies were conducted. The maximum uptake capacity of the plant was recorded as 0.05 mg/g of Cr(VI) at the equilibrium level after a contact period of 7 days for an initial concentration of 8 mg /L, although severe physiological damage occurred. The experimental results were plotted in Langmuir and Freundlich isotherm models and both were found to be well fitted (r(2) = 0.979 and r(2) = 0.974 respectively). The high value of n (2.16) reveals a strong bond between the plant root and dissolved Cr(VI), which favours the adsorption process. The order of the reaction was also examined on the basis of uptake capacity and it was found that the second order model fitted best.

Documentation and Monitoring of Built Heritage in Abu Dhabi, Uae

NASA Astrophysics Data System (ADS)

Muhammad, S.

2013-07-01

The ancient oasis-city of Al Ain in Abu Dhabi Emirate still retains the most important and outstanding cultural heritage of United Arab Emirates (UAE). The larger area of Abu Dhabi Emirate comprised of archaeological sites, cultural landscapes and historic buildings dating back to 3rd millennium to the recent pre-oil era. Traditional materials like stone, earth and palm wood were used in combination with local construction methods. For the last seven years the newly formed Abu Dhabi Tourism & Culture Authority (TCA Abu Dhabi)1 has been actively involved in conservation of built heritage in Abu Dhabi Emirate with the help of its Conservation Section. Documentation prior to any conservation and restoration works is considered as a basic pre-requisite for understanding an historic building or site. It is a process which continues during the conservation of any monument and is the only accurate tool for recording information in order to understand the structure, ultimately leading to the management of cultural heritage. Application and use of tools, ranging from basic manual techniques to 3D laser scanning, based on the best practices and international guidelines the exercise will help in establishing a documentation lab with standard procedures, specifications and tools for the documentation and monitoring the built heritage of Abu Dhabi Emirate. This paper will discuss a range of case studies and will demonstrate how documentation and monitoring of the built heritage has augmented the various conservation initiatives on a variety of building types.

75 FR 80818 - Funding Availability for Title VI Grant Applications; Extension

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-23

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Administration on Aging Funding Availability for Title VI... Administration on Aging is extending the date for which the Title VI grants applications for the grant period... on March 31, 2011. Funding Opportunity Title/Program Name: Older Americans Act (OAA), Title VI, Part...

GWM-VI: groundwater management with parallel processing for multiple MODFLOW versions

USGS Publications Warehouse

Banta, Edward R.; Ahlfeld, David P.

2013-01-01

Groundwater Management–Version Independent (GWM–VI) is a new version of the Groundwater Management Process of MODFLOW. The Groundwater Management Process couples groundwater-flow simulation with a capability to optimize stresses on the simulated aquifer based on an objective function and constraints imposed on stresses and aquifer state. GWM–VI extends prior versions of Groundwater Management in two significant ways—(1) it can be used with any version of MODFLOW that meets certain requirements on input and output, and (2) it is structured to allow parallel processing of the repeated runs of the MODFLOW model that are required to solve the optimization problem. GWM–VI uses the same input structure for files that describe the management problem as that used by prior versions of Groundwater Management. GWM–VI requires only minor changes to the input files used by the MODFLOW model. GWM–VI uses the Joint Universal Parameter IdenTification and Evaluation of Reliability Application Programming Interface (JUPITER-API) to implement both version independence and parallel processing. GWM–VI communicates with the MODFLOW model by manipulating certain input files and interpreting results from the MODFLOW listing file and binary output files. Nearly all capabilities of prior versions of Groundwater Management are available in GWM–VI. GWM–VI has been tested with MODFLOW-2005, MODFLOW-NWT (a Newton formulation for MODFLOW-2005), MF2005-FMP2 (the Farm Process for MODFLOW-2005), SEAWAT, and CFP (Conduit Flow Process for MODFLOW-2005). This report provides sample problems that demonstrate a range of applications of GWM–VI and the directory structure and input information required to use the parallel-processing capability.

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

PubMed

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.

40 CFR Appendix Vi to Part 1039 - Nonroad Compression-ignition Composite Transient Cycle

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Nonroad Compression-ignition Composite Transient Cycle VI Appendix VI to Part 1039 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... ENGINES Pt. 1039, App. VI Appendix VI to Part 1039—Nonroad Compression-ignition Composite Transient Cycle...

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

PubMed Central

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. 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 VI are significantly

IN SITU SOURCE TREATMENT OF CR(VI) USING A FE(II)-BASED REDUCTANT BLEND: LONG-TERM MONITORING AND EVALUATION

EPA Science Inventory

The long-term effectiveness of a FeSO4 + Na2S2O4 reductant solution blend for in situ saturated zone treatment of dissolved and solid phase Cr(VI) in a high pH chromite ore processing solid waste (COPSW) fill material was investigated. Two field pilot injection studies were cond...

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

DOE PAGES

McClain, Cynthia N.; Fendorf, Scott; Webb, Samuel M.; ...

2016-11-22

Here, 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 bymore » 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.« less

[Treatment of wastewater containing Cr(VI) by LDH synthesizing in situ].

PubMed

Chen, Tian-hu; Feng, You-liang; Xu, Hui-fang; Peng, Shu-chuan; Huang, Chuan-hui; Tang, Shu-pei

2004-03-01

The objective of this work was to investigate the efficiency and factors impacting of removal Cr(VI) from wastewater by layer double hydroxide synthesizing in situ. Principle of the method may be described as follow: Mg2+ and Al3+ hydrolysis and forms Mg/Al-LDH by adding Mg2+, Al3+ and NaOH into wastewater containing Cr(VI), Cr(VI) anions are selectively intercalated into interlayer of LDH to balance positive structural charge. While Mg2+ and Al3+ co-precipitates and forms LDH, the Cr(VI) in wastewater is removal by settle of LDH synthesizing in situ, which are confirmed by analysis of X-ray diffraction on settle and chemical analysis on aqueous. The results indicate that factors of impacting on efficiency of removal Cr(VI) include in amount of adding Mg2+ and Al3+, Mg/Al ratio, pH and concentration of Cr(VI) in wastewater. The maximal removal efficiency of Cr(VI) can be reached when pH values are between 8.5 and 9, and Mg/Al ratios are between 1:1 and 2:1, meanwhile, Mg and Al added can be taken good use of. This technology has present extraordinary efficiency of wastewater treatment.

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

PubMed

Praveen, Prashant; Loh, Kai-Chee

2016-08-15

Solid/liquid extraction of Cr(VI) was accomplished using trioctylphosphine oxide impregnated polypropylene hollow fiber membranes. Extraction of 100-500mg/L Cr(VI) by the extractant impregnated membranes (EIM) was characterized by high uptake rate and capacity, and equilibrium was attained within 45min of contact. Extraction equilibrium was pH-dependent (at an optimal pH 2), whereas stripping using 0.2M sodium hydroxide yielded the highest recovery of 98% within 60min. 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 37-49kJ/mol and 114-155J/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. Copyright © 2016 Elsevier B.V. All rights reserved.

Kinetics of reduction of plutonium(VI) and neptunium(VI) by sulfide in neutral and alkaline solutions

USGS Publications Warehouse

Nash, K.L.; Cleveland, J.M.; Sullivan, J.C.; Woods, M.

1986-01-01

The rate of reduction of plutonium(VI) and neptunium(VI) by bisulfide ion in neutral and mildly alkaline solutions has been investigated by the stopped-flow technique. The reduction of both of these ions to the pentavalent oxidation state appears to occur in an intramolecular reaction involving an unusual actinide(VI)-hydroxide-bisulfide complex. For plutonium the rate of reduction is 27.4 (??4.1) s-1 at 25??C with ??H* = +33.2 (??1.0) kJ/mol and ??S* = -106 (??4) J/(mol K). The apparent stability constant for the transient complex is 4.66 (??0.94) ?? 103 M-1 at 25??C with associated thermodynamic parameters of ??Hc = +27.7 (??0.4) kJ/mol and ??Sc = +163 (??2) J/(mol K). The corresponding rate and stability constants are determined for the neptunium system at 25??C (k3 = 139 (??30) s-1, Kc. = 1.31 (??0.32) ?? 103 M-1), but equivalent parameters cannot be determined at reduced temperatures. The reaction rate is decreased by bicarbonate ion. At pH > 10.5, a second reaction mechanism, also involving a sulfide complex, is indicated. ?? 1986 American Chemical Society.

II-VI Narrow-Bandgap Semiconductors for Optoelectronics

NASA Astrophysics Data System (ADS)

Baker, Ian

The field of narrow-gap II-VI materials is dominated by the compound semiconductor mercury cadmium telluride, (Hg1-x Cd x Te or MCT), which supports a large industry in infrared detectors, cameras and infrared systems. It is probably true to say that HgCdTe is the third most studied semiconductor after silicon and gallium arsenide. Hg1-x Cd x Te is the material most widely used in high-performance infrared detectors at present. By changing the composition x the spectral response of the detector can be made to cover the range from 1 μm to beyond 17 μm. The advantages of this system arise from a number of features, notably: close lattice matching, high optical absorption coefficient, low carrier generation rate, high electron mobility and readily available doping techniques. These advantages mean that very sensitive infrared detectors can be produced at relatively high operating temperatures. Hg1-x Cd x Te multilayers can be readily grown in vapor-phase epitaxial processes. This provides the device engineer with complex doping and composition profiles that can be used to further enhance the electro-optic performance, leading to low-cost, large-area detectors in the future. The main purpose of this chapter is to describe the applications, device physics and technology of II-VI narrow-bandgap devices, focusing on HgCdTe but also including Hg1-x Mn x Te and Hg1-x Zn x Te. It concludes with a review of the research and development programs into third-generation infrared detector technology (so-called GEN III detectors) being performed in centers around the world.

A highly selective chemiluminescent probe for the detection of chromium(VI)

NASA Astrophysics Data System (ADS)

Jin, Yan; Sun, Yonghua; Li, Chongying; Yang, Chao

2018-03-01

In present work, rhodamine B hydrazide and rhodamine 6G hydrazide were synthesized and the chemiluminescence performance has been investigated. Based on the chemiluminescence of rhodamine 6G hydrazide-chromium(VI), a selective and sensitive method for the direct detection of chromium(VI) was developed. The chemiluminescence intensity was linearly related to the concentration of chromium(VI) in the range of 2.60 × 10- 8-8.00 × 10- 6 mol/L with a correlation coefficient of r = 0.998 and a detection limit of 1.4 × 10- 8 mol/L (S/N = 3). The results indicated rhodamine 6G hydrazide was an excellent chemiluminescent probe for chromium(VI) without reduction of chromium(VI) to chromium(III). A possible mechanism of CL emission was also suggested.

Long-term diffusion of U(VI) in bentonite: Dependence on density

DOE PAGES

Joseph, Claudia; Mibus, Jens; Trepte, Paul; ...

2016-10-12

As a contribution to the safety assessment of nuclear waste repositories, U(VI) diffusion through the potential buffer material MX-80 bentonite was investigated at three clay dry densities over six years. Synthetic MX-80 model pore water was used as background electrolyte. Speciation calculations showed that Ca 2UO 2(CO 3) 3(aq) was the main U(VI) species. The in- and out-diffusion of U(VI) was investigated separately. U(VI) diffused about 3 mm, 1.5 mm, and 1 mm into the clay plug at ρ = 1.3, 1.6, and 1.9 g/cm 3, respectively. No through-diffusion of the U(VI) tracer was observed. However, leaching of natural uraniummore » contained in the clay occurred and uranium was detected in all receiving reservoirs. As expected, the effective and apparent diffusion coefficients, D e and D a, decreased with increasing dry density. The D a values for the out-diffusion of natural U(VI) were in good agreement with previously determined values. Surprisingly, D a values for the in-diffusion of U(VI) were about two orders of magnitude lower than values obtained in short-term in-diffusion experiments reported in the literature. Some potential reasons for this behavior that were evaluated are changes of the U(VI) speciation within the clay (precipitation, reduction) or changes of the clay porosity and pore connectivity with time. By applying Archie's law and the extended Archie's law, it was estimated that a significantly smaller effective porosity must be present for the long-term in-diffusion of U(VI). Finally, the results suggest that long-term studies of key transport phenomena may reveal additional processes that can directly impact long-term repository safety assessments.« less

HNO3 modified biochars for uranium (VI) removal from aqueous solution.

PubMed

Jin, Jie; Li, Shiwei; Peng, Xianqiang; Liu, Wei; Zhang, Chenlu; Yang, Yan; Han, Lanfang; Du, Ziwen; Sun, Ke; Wang, Xiangke

2018-05-01

The HNO 3 treatment was used to chemically modify the biochars produced from wheat straw (WH) and cow manure for U(VI) removal from aqueous solution. Macroscopic experiments proved that the enrichment of U(VI) on the biochars was regulated by surface complexation and electrostatic interactions. FTIR and XPS analyses confirmed that the highly efficient adsorption of U(VI) was due to the carboxyl groups on the biochar surfaces. The reducing agents of the R-CH 2 OH groups facilitated U(VI) adsorption on the untreated biochars. Owing to the higher contents of surface COO groups and more negative surface charge, the modified biochars showed enhanced U(VI) adsorption ability than the untreated ones. The maximum adsorption capacity of U(VI) by the oxidized WH was calculated to be 355.6 mg/g at pH 4.5 and 298 K, which was an improvement of 40 times relative to the untreated WH and was higher than that of most carbon-based adsorbents. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

PubMed

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.

Ferrate(VI)-prompted removal of metals in aqueous media: mechanistic delineation of enhanced efficiency via metal entrenchment in magnetic oxides.

PubMed

Prucek, Robert; Tuček, Jiří; Kolařík, Jan; Hušková, Ivana; Filip, Jan; Varma, Rajender S; Sharma, Virender K; Zbořil, Radek

2015-02-17

The removal efficiency of heavy metal ions (cadmium(II), Cd(II); cobalt(II), Co(II); nickel(II), Ni(II); copper(II), Cu(II)) by potassium ferrate(VI) (K2FeO4, Fe(VI)) was studied as a function of added amount of Fe(VI) (or Fe) and varying pH. At pH = 6.6, the effective removal of Co(II), Ni(II), and Cu(II) from water was observed at a low Fe-to-heavy metal ion ratio (Fe/M(II) = 2:1) while a removal efficiency of 70% was seen for Cd(II) ions at a high Fe/Cd(II) weight ratio of 15:1. The role of ionic radius and metal valence state was explored by conducting similar removal experiments using Al(III) ions. The unique combination of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), in-field Mössbauer spectroscopy, and magnetization measurements enabled the delineation of several distinct mechanisms for the Fe(VI)-prompted removal of metal ions. Under a Fe/M weight ratio of 5:1, Co(II), Ni(II), and Cu(II) were removed by the formation of MFe2O4 spinel phase and partially through their structural incorporation into octahedral positions of γ-Fe2O3 (maghemite) nanoparticles. In comparison, smaller sized Al(III) ions got incorporated easily into the tetrahedral positions of γ-Fe2O3 nanoparticles. In contrast, Cd(II) ions either did not form the spinel ferrite structure or were not incorporated into the lattic of iron(III) oxide phase due to the distinct electronic structure and ionic radius. Environmentally friendly removal of heavy metal ions at a much smaller dosage of Fe than those of commonly applied iron-containing coagulants and the formation of ferrimagnetic species preventing metal ions leaching back into the environment and allowing their magnetic separation are highlighted.

Treatment of Alkaline Cr(VI)-Contaminated Leachate with an Alkaliphilic Metal-Reducing Bacterium.

PubMed

Watts, Mathew P; Khijniak, Tatiana V; Boothman, Christopher; Lloyd, Jonathan R

2015-08-15

Chromium in its toxic Cr(VI) valence state is a common contaminant particularly associated with alkaline environments. A well-publicized case of this occurred in Glasgow, United Kingdom, where poorly controlled disposal of a cementitious industrial by-product, chromite ore processing residue (COPR), has resulted in extensive contamination by Cr(VI)-contaminated alkaline leachates. In the search for viable bioremediation treatments for Cr(VI), a variety of bacteria that are capable of reduction of the toxic and highly soluble Cr(VI) to the relatively nontoxic and less mobile Cr(III) oxidation state, predominantly under circumneutral pH conditions, have been isolated. Recently, however, alkaliphilic bacteria that have the potential to reduce Cr(VI) under alkaline conditions have been identified. This study focuses on the application of a metal-reducing bacterium to the remediation of alkaline Cr(VI)-contaminated leachates from COPR. This bacterium, belonging to the Halomonas genus, was found to exhibit growth concomitant to Cr(VI) reduction under alkaline conditions (pH 10). Bacterial cells were able to rapidly remove high concentrations of aqueous Cr(VI) (2.5 mM) under anaerobic conditions, up to a starting pH of 11. Cr(VI) reduction rates were controlled by pH, with slower removal observed at pH 11, compared to pH 10, while no removal was observed at pH 12. The reduction of aqueous Cr(VI) resulted in the precipitation of Cr(III) biominerals, which were characterized using transmission electron microscopy and energy-dispersive X-ray analysis (TEM-EDX) and X-ray photoelectron spectroscopy (XPS). The effectiveness of this haloalkaliphilic bacterium for Cr(VI) reduction at high pH suggests potential for its use as an in situ treatment of COPR and other alkaline Cr(VI)-contaminated environments. Copyright © 2015, Watts et al.

A study of the kinetics and isotherms for Cr(VI) adsorption in a binary mixture of Cr(VI)-Ni(II) using hierarchical porous carbon obtained from pig bone.

PubMed

Li, Chengxian; Huang, Zhe; Huang, Bicheng; Liu, Changfeng; Li, Chengming; Huang, Yaqin

2014-01-01

Cr(VI) adsorption in a binary mixture Cr(VI)-Ni(II) using the hierarchical porous carbon prepared from pig bone (HPC) was investigated. The various factors affecting adsorption of Cr(VI) ions from aqueous solutions such as initial concentration, pH, temperature and contact time were analyzed. The results showed excellent efficiency of Cr(VI) adsorption by HPC. The kinetics and isotherms for Cr(VI) adsorption from a binary mixture Cr(VI)-Ni(II) by HPC were studied. The adsorption equilibrium described by the Langmuir isotherm model is better than that described by the Freundlich isotherm model for the binary mixture in this study. The maximum adsorption capacity was reliably found to be as high as 192.68 mg/g in the binary mixture at pH 2. On fitting the experimental data to both pseudo-first- and second-order equations, the regression analysis of the second-order equation gave a better R² value.

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

DOEpatents

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.

Uranium(VI) adsorption to ferrihydrite: Application of a surface complexation model

USGS Publications Warehouse

Waite, T.D.; Davis, J.A.; Payne, T.E.; Waychunas, G.A.; Xu, N.

1994-01-01

A study of U(VI) adsorption by ferrihydrite was conducted over a wide range of U(VI) concentrations, pH, and at two partial pressures of carbon dioxide. A two-site (strong- and weak-affinity sites, FesOH and FewOH, respectively) surface complexation model was able to describe the experimental data well over a wide range of conditions, with only one species formed with each site type: an inner-sphere, mononuclear, bidentate complex of the type (FeO2)UO2. The existence of such a surface species was supported by results of uranium EXAFS spectroscopy performed on two samples with U(VI) adsorption density in the upper range observed in this study (10 and 18% occupancy of total surface sites). Adsorption data in the alkaline pH range suggested the existence of a second surface species, modeled as a ternary surface complex with UO2CO30 binding to a bidentate surface site. Previous surface complexation models for U(VI) adsorption have proposed surface species that are identical to the predominant aqueous species, e.g., multinuclear hydrolysis complexes or several U(VI)-carbonate complexes. The results demonstrate that the speciation of adsorbed U(VI) may be constrained by the coordination environment at the surface, giving rise to surface speciation for U(VI) that is significantly less complex than aqueous speciation.

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

Code of Federal Regulations, 2010 CFR

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...

Ferrate(VI) oxidation of polychlorinated diphenyl sulfides: Kinetics, degradation, and oxidized products.

PubMed

Chen, Jing; Xu, Xinxin; Zeng, Xiaolan; Feng, Mingbao; Qu, Ruijuan; Wang, Zunyao; Nesnas, Nasri; Sharma, Virender K

2018-06-13

This paper presents oxidation of polychlorinated diphenyl sulfides (PCDPSs), dioxin-like compounds, by ferrate(VI) (Fe VI O 4 2- , Fe(VI)). Kinetics of the reactions of Fe(VI) with seventeen PCDPSs, differ in number and positions of chlorine atoms (from 2 to 7), were investigated at pH 8.0. The second-order rate constants (k, M -1 s -1 ) of the reactions varied with the numbers and positions of chlorine atoms and appeared to be related with standard Gibbs free energy of formation (Δ f G 0 ) of PCDPSs. Degradation experiments in the presence of ions and humic acid demonstrated complete removal of PeCDPS by Fe(VI) in minutes. Pathways of the reaction were investigated by identifying oxidized products (OPs) of the reaction between Fe(VI) and 2,2',3',4,5-pentachlorodiphenyl sulfide (PeCDPS) at pH 8.0. Pathways of oxidation involved major pathway of attack on sulfur(II) by Fe(VI) in steps to yield sulfoxide type products, and subsequent breakage of C-S bond with the formation of sulfonic acid-containing trichloro compound. Minor pathways were hydroxylation of benzene ring and substitution of chlorine atom with hydroxyl group. Estimation of toxicity of OPs of the oxidation of PeCDPS by Fe(VI) suggested the decreased toxicity from the parent contaminant. Copyright © 2018. Published by Elsevier Ltd.

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

PubMed

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.

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

PubMed

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.

Inactivation of bacteriophage MS2 with potassium ferrate(VI).

PubMed

Hu, Lanhua; Page, Martin A; Sigstam, Therese; Kohn, Tamar; Mariñas, Benito J; Strathmann, Timothy J

2012-11-06

Ferrate [Fe(VI); FeO(4)(2-)] is an emerging oxidizing agent capable of controlling chemical and microbial water contaminants. Here, inactivation of MS2 coliphage by Fe(VI) was examined. The inactivation kinetics observed in individual batch experiments was well described by a Chick-Watson model with first-order dependences on disinfectant and infective phage concentrations. The inactivation rate constant k(i) at a Fe(VI) dose of 1.23 mgFe/L (pH 7.0, 25 °C) was 2.27(±0.05) L/(mgFe × min), corresponding to 99.99% inactivation at a Ct of ~4 (mgFe × min)/L. Measured k(i) values were found to increase with increasing applied Fe(VI) dose (0.56-2.24 mgFe/L), increasing temperature (5-30 °C), and decreasing pH conditions (pH 6-11). The Fe(VI) dose effect suggested that an unidentified Fe byproduct also contributed to inactivation. Temperature dependence was characterized by an activation energy of 39(±6) kJ mol(-1), and k(i) increased >50-fold when pH decreased from 11 to 6. The pH effect was quantitatively described by parallel reactions with HFeO(4)(-) and FeO(4)(2-). Mass spectrometry and qRT-PCR analyses demonstrated that both capsid protein and genome damage increased with the extent of inactivation, suggesting that both may contribute to phage inactivation. Capsid protein damage, localized in the two regions containing oxidant-sensitive cysteine residues, and protein cleavage in one of the two regions may facilitate genome damage by increasing Fe(VI) access to the interior of the virion.

Research progress in the use of ferrate(VI) for the environmental remediation.

PubMed

Jiang, J Q

2007-07-31

The aim of this paper is to review the research progress of using ferrate(VI) in following fields of environmental remediation: (1) water disinfection; (2) degradation of synthetic organic pollutants; (3) treatment of emerging organic pollutants; (4) oxidation of inorganic pollutants; (5) removing humic substance; (6) wastewater treatment and disinfection; and (7) sewage sludge treatment. Whilst the superior performance of potassium ferrate(VI) as an oxidant/disinfectant for the environmental remediation has been demonstrated in various recent researches, challenges have existed to the implementation of ferrate(VI) technology in full-scale water, wastewater and sewage sludge treatment owing to either the instability property of a ferrate(VI) solution or a high preparation cost of a solid ferrate(VI). In addition to this, there are some fundamental issues which have not yet been studied thoroughly which are crucial for the implementation of ferrate(VI)-these lead to the future research work recommended by this paper.

Hydrothermal synthesis of Bi2WO6 and photocatalytic reduction of aqueous Cr(VI) under visible light irradiation

NASA Astrophysics Data System (ADS)

Li, Jing; Shi, Qingzhu; Chen, Yan; Song, Ming

2017-12-01

Bi2WO6 was synthesized via a facile hydrothermal method using different inorganic acid or alkali varied pH of the solution at 180℃ for 12 h, and characterized by X-ray diffraction, FESEM and photocurrent. Furthermore, the photocatalytic activity of Bi2WO6 was investigated in the reduction of aqueous Cr(VI) under visible light (λ > 420 nm) irradiation. As a result, assynthesized Bi2WO6 was an orthorhombic phase, and well-crystallized with 3D hierarchical structure constructed by arranged 2D layers of nanoplates. All the as-synthesized Bi2WO6 exhibited the visible light photocatalytic activities on aqueous Cr(VI), and Bi2WO6-(2) exhibited the highest photocatalytic reduction efficiency based on much higher separation and transfer efficiency of photogenerated electrons and holes.

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

USGS Publications Warehouse

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.

Cr(VI) Adsorption on Red Mud Modified by Lanthanum: Performance, Kinetics and Mechanisms

PubMed Central

Cui, You-Wei; Li, Jie; Du, Zhao-Fu; Peng, Yong-Zhen

2016-01-01

Water pollution caused by the highly toxic metal hexavalent chromium (Cr(VI)) creates significant human health and ecological risks. In this study, a novel adsorbent was used to treat Cr(VI)-containing wastewater; the adsorbent was prepared using red mud (RM) generated from the alumina production industry and the rare earth element lanthanum. This study explored adsorption performance, kinetics, and mechanisms. Results showed that the adsorption kinetics of the RM modified by lanthanum (La-RM), followed the pseudo-second-order model, with a rapid adsorption rate. Cr(VI) adsorption was positively associated with the absorbent dose, pH, temperature, and initial Cr(VI) concentration; coexisting anions had little impact. The maximum Cr(VI) adsorption capacity was 17.35 mg/g. Cr(VI) adsorption on La-RM was a mono-layer adsorption pattern, following the Langmuir isotherm model. Thermodynamic parameters showed the adsorption was spontaneous and endothermic. The adsorption of Cr(VI) on La-RM occurred as a result of LaOCl formation on the RM surface, which in turn further reacted with Cr(VI) in the wastewater. This study highlighted a method for converting industrial waste into a valuable material for wastewater treatment. The novel absorbent could be used as a potential adsorbent for treating Cr(VI)-contaminating wastewater, due to its cost-effectiveness and high adsorption capability. PMID:27658113

Cr(VI) remediation by enriched sediment with anthraquinone-2,6-disulfonate as electron shuttles

NASA Astrophysics Data System (ADS)

Chen, Hong; Li, Xiaojuan; Xu, Zhiwei

Hexavalent chromium (Cr(VI)) is a priority pollutant in the USA and many other countries. This study investigated the simultaneous remediation of Cr(VI) in sediment enriched with quinone-reducing microorganisms via a closely coupled, biotic-abiotic pathway. The results showed that Cr(VI) remediation was achieved by sediment adsorption and reduction of quinone-reducing microorganism. Moreover, microorganism reduction of Cr(VI) could be continued when sediment adsorption was saturated after long-term Cr(VI) remediation. The acetate and anthraquinone-2,6-disulfonate (AQDS), which acted as exogenous carbon and electron shuttle, respectively, were two crucial factors. The optimum concentrations of acetate and AQDS were 5 mM and 1 mM when the initial Cr(VI) concentration was 10 mg/L. AQDS was recycled, and it acted in a catalytic-type manner for the bacterial reduction of Cr(VI). Thus, biological humus reduction might provide an extensive pathway for the sequestration and detoxification of Cr(VI) in anaerobic soils, water, and industrial effluents.

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

PubMed

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 0.15vi absorbers are located near galaxies and are highly displaced from the quasar 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.

Immunogenicity and safety of the Vi-CRM197 conjugate vaccine against typhoid fever in adults, children, and infants in south and southeast Asia: results from two randomised, observer-blind, age de-escalation, phase 2 trials.

PubMed

Bhutta, Zulfiqar A; Capeding, Maria Rosario; Bavdekar, Ashish; Marchetti, Elisa; Ariff, Shabina; Soofi, Sajid B; Anemona, Alessandra; Habib, Muhammad A; Alberto, Edison; Juvekar, Sanjay; Khan, Rana M Qasim; Marhaba, Rachid; Ali, Noshad; Malubay, Nelia; Kawade, Anand; Saul, Allan; Martin, Laura B; Podda, Audino

2014-02-01

Typhoid vaccination is a public health priority in developing countries where young children are greatly affected by typhoid fever. Because present vaccines are not recommended for children younger than 2 years, the Novartis Vaccines Institute for Global Health developed a conjugate vaccine (Vi-CRM197) for infant immunisation. We aimed to assess the immunogenicity and safety of Vi-CRM197 in participants of various ages in endemic countries in south and southeast Asia. We did two randomised, observer-blind, age de-escalation, phase 2 trials at two sites in Pakistan and India (study A), and at one site in the Philippines (study B), between March 2, 2011, and Aug 9, 2012. Adults aged 18-45 years, children aged 24-59 months, older infants aged 9-12 months, and infants aged 6-8 weeks were randomly assigned (1:1) with a computer-generated randomisation list (block size of four) to receive either 5 μg Vi-CRM197 or 25 μg Vi-polysaccharide vaccine (or 13-valent pneumococcal conjugate vaccine in children younger than 2 years). Both infant populations received Vi-CRM197 concomitantly with vaccines of the Expanded Programme on Immunization (EPI), according to WHO schedule. With the exception of designated study site personnel responsible for vaccine preparation, study investigators, those assessing outcomes, and data analysts were masked to treatment allocation. We specified no a-priori null hypothesis for the immunogenicity or safety objectives and all analyses were descriptive. Analyses were by modified intention-to-treat. These studies are registered with ClinicalTrials.gov, numbers NCT01229176 and NCT01437267. 320 participants were enrolled and vaccinated in the two trials: 200 in study A (all age groups) and 120 in study B (children and infants only), of whom 317 (99%) were included in the modified intention-to-treat analysis. One dose of Vi-CRM197 significantly increased concentrations of anti-Vi antibody in adults (from 113 U/mL [95% CI 67-190] to 208 U/mL [117

Modeling uranium(VI) adsorption onto montmorillonite under varying carbonate concentrations: A surface complexation model accounting for the spillover effect on surface potential

NASA Astrophysics Data System (ADS)

Tournassat, C.; Tinnacher, R. M.; Grangeon, S.; Davis, J. A.

2018-01-01

The prediction of U(VI) adsorption onto montmorillonite clay is confounded by the complexities of: (1) the montmorillonite structure in terms of adsorption sites on basal and edge surfaces, and the complex interactions between the electrical double layers at these surfaces, and (2) U(VI) solution speciation, which can include cationic, anionic and neutral species. Previous U(VI)-montmorillonite adsorption and modeling studies have typically expanded classical surface complexation modeling approaches, initially developed for simple oxides, to include both cation exchange and surface complexation reactions. However, previous models have not taken into account the unique characteristics of electrostatic surface potentials that occur at montmorillonite edge sites, where the electrostatic surface potential of basal plane cation exchange sites influences the surface potential of neighboring edge sites ('spillover' effect). A series of U(VI) - Na-montmorillonite batch adsorption experiments was conducted as a function of pH, with variable U(VI), Ca, and dissolved carbonate concentrations. Based on the experimental data, a new type of surface complexation model (SCM) was developed for montmorillonite, that specifically accounts for the spillover effect using the edge surface speciation model by Tournassat et al. (2016a). The SCM allows for a prediction of U(VI) adsorption under varying chemical conditions with a minimum number of fitting parameters, not only for our own experimental results, but also for a number of published data sets. The model agreed well with many of these datasets without introducing a second site type or including the formation of ternary U(VI)-carbonato surface complexes. The model predictions were greatly impacted by utilizing analytical measurements of dissolved inorganic carbon (DIC) concentrations in individual sample solutions rather than assuming solution equilibration with a specific partial pressure of CO2, even when the gas phase was

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Bin; Ahmed, B.; Kennedy, David W.

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 uponmore » 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.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, Philip E.; Williams, Kenneth H.; Davis, James A.

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 suggestedmore » 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.« less

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

NASA Astrophysics Data System (ADS)

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

[Kinetics modeling and reaction mechanism of ferrate(VI) oxidation of triclosan].

PubMed

Yang, Bin; Ying, Guang-Guo; Zhao, Jian-Liang

2011-09-01

Triclosan (TCS) is a broad-spectrum antibacterial agent widely used in many personal care products. We investigated oxidation of TCS by aqueous ferrate Fe(VI) to determine reaction kinetics, interpreted the reaction mechanism by a linear free-energy relationship, and evaluated the degradation efficiency. Second-order reaction kinetics was used to model Fe (VI) oxidation of TCS, with the apparent second-order rate constant (k(app)) being 531.9 L x (mol x s)(-1) at pH 8.5 and (24 +/- 1) degrees C. The half life (t1/2) is 25.8 s for an Fe( VI) concentration of 10 mg x L(-1). The rate constants of the reaction decrease with increasing pH values. These pH-dependent variations in k(app) could be distributed by considering species-specific reactions between Fe(VI) species and acid-base species of an ionizable TCS. Species-specific second-order reaction rate constants, k, were determined for reaction of HFeO4(-) with each of TCS's acid-base species. The value of k determined for neutral TCS was (4.1 +/- 3.5) x 10(2) L x (mol x s)(-1), while that measured for anionic TCS was (1.8 +/- 0.1) x 10(4) L x (mol x s)(-1). The reaction between HFeO4(-) and the dissociated TCS controls the overall reaction. A linear free-energy relationship illustrated the electrophilic oxidation mechanism. Fe (VI) reacts initially with TCS by electrophilic attack at the latter's phenol moiety. At a n[Fe(VI)]: n(TCS) > 7: 1, complete removal of TCS was achieved. And lower concentration of the humic acid could enhance the k(app) of Fe( VI) with TCS. In conclusion, Fe(VI) oxidation technology appears to be a promising tool for applications of WWTPs effluents and other decontamination processes.

Hereditary motor and sensory neuropathy type VI with optic atrophy.

PubMed

Voo, Irene; Allf, Bryan E; Udar, Nitin; Silva-Garcia, Rosamaria; Vance, Jeffrey; Small, Kent W

2003-10-01

To present the detailed clinical findings of a large family with hereditary motor and sensory neuropathy type VI (HMSN VI), a syndrome featuring optic atrophy. Observational case series. A detailed history was obtained and physical examination was made of the extended family of the proband for evidence of neurologic dysfunction. The OPA1 gene was screened for mutations by direct DNA sequencing. Twelve of 97 family members examined are affected with signs of HMSN VI. Three other members have either optic atrophy or peripheral neuropathy, thus allowing an appreciation of the full clinical spectrum of disease. No mutations were found in the OPA1 gene. This family demonstrates the variable expressivity of this disorder as well as incomplete penetrance. This is the largest known family with HMSN VI. No association was found with changes in the OPA1 gene.

Determination of Cr(III) solids formed by reduction of Cr(VI) in a contaminated fractured bedrock aquifer: evidence for natural attenuation of Cr(VI)

EPA Science Inventory

Hexavalent chromium Cr(VI) is toxic and can be highly mobile in many aquifer systems. Redox reactions with naturally occurring minerals and organic compounds can reduce Cr(VI) to Cr(III), forming labile Cr(III) oxyhydroxide precipitates, which is a natural attenuation process. In...

Role of an organic carbon-rich soil and Fe(III) reduction in reducing the toxicity and environmental mobility of chromium(VI) at a COPR disposal site.

PubMed

Ding, Weixuan; Stewart, Douglas I; Humphreys, Paul N; Rout, Simon P; Burke, Ian T

2016-01-15

Cr(VI) is an important contaminant found at sites where chromium ore processing residue (COPR) is deposited. No low cost treatment exists for Cr(VI) leaching from such sites. This study investigated the mechanism of interaction of alkaline Cr(VI)-containing leachate with an Fe(II)-containing organic matter rich soil beneath the waste. The soil currently contains 0.8% Cr, shown to be present as Cr(III)(OH)3 in EXAFS analysis. Lab tests confirmed that the reaction of Cr(VI) in site leachate with Fe(II) present in the soil was stoichiometrically correct for a reductive mechanism of Cr accumulation. However, the amount of Fe(II) present in the soil was insufficient to maintain long term Cr(VI) reduction at historic infiltration rates. The soil contains a population of bacteria dominated by a Mangroviflexus-like species, that is closely related to known fermentative bacteria, and a community capable of sustaining Fe(III) reduction in alkaline culture. It is therefore likely that in situ fermentative metabolism supported by organic matter in the soil produces more labile organic substrates (lactate was detected) that support microbial Fe(III) reduction. It is therefore suggested that addition of solid phase organic matter to soils adjacent to COPR may reduce the long term spread of Cr(VI) in the environment. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Cr(VI) Occurrence and Geochemistry in Water From Public-Supply Wells in California

DOE PAGES

Izbicki, John A.; Wright, Michael T.; Seymour, Whitney A.; ...

2015-08-18

Hexavalent chromium, Cr(VI), in 918 wells sampled throughout California between 2004 and 2012 by the Groundwater Ambient Monitoring and Assessment Program—Priority Basin Project (GAMA—PBP) ranged from less than the study reporting limit (SRL) of 1 microgram per liter (μg/L) to 32 μg/L. Statewide, Cr(VI) was reported in 31 percent of sampled 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 sampled wells. Cr(VI) data collected for regulatory purposes overestimate Cr(VI) occurrence. Ninety percent of chromium was present as Cr(VI), which was detected more frequently and atmore » 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 abundance in source rock eroded to form those aquifers, and areal recharge processes (including irrigation return) that 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.« less

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

USGS Publications Warehouse

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.

Characterization of the biochemical-pathway of uranium (VI) reduction in facultative anaerobic bacteria.

PubMed

Mtimunye, Phalazane J; Chirwa, Evans M N

2014-10-01

Cultures of U(VI) reducing bacteria sourced from abandoned uranium mine tailing dam were evaluated for their ability to reduce U(VI) to U(IV). The species in the cultures reduced U(VI) in solutions with initial U(VI) concentration up to 400mgL(-)(1) under a near neutral pH of 6.5. The electron flow pathway and fate of reduced species was also analysed in the individual species in order to evaluate the potential for control and optimisation of the reduction potential at the biochemical level. The results showed that U(VI) reduction in live cells was completely blocked by the NADH-dehydrogenase inhibitor, rotenone (C23H22O6), and thioredoxin inhibitor, cadmium chloride (CdCl2), showing that U(VI) reduction involves the electron flow through NADH-dehydrogenase, a primary electron donor to the electron transport respiratory (ETR) system. Mass balance analysis of uranium species aided by visual and electron microscopy suggest that most U(VI) reduction occurred on the cell surface of the isolated species. This finding indicates the possibility of easy uranium recovery for beneficial use through biological remediation. Should the U(VI) be reduced inside the cell, recovery would require complete disruption of the cells and therefore would be difficult. The study contributes new knowledge on the underlying mechanisms in the U(VI) reduction in facultative anaerobes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Oxidation of diclofenac by potassium ferrate (VI): reaction kinetics and toxicity evaluation.

PubMed

Wang, Yingling; Liu, Haijin; Liu, Guoguang; Xie, Youhai; Gao, Shuyan

2015-02-15

The reaction kinetics and toxicity of diclofenac (DCF) oxidation by ferrate (VI) under simulated water disinfection conditions were investigated. Experimental results indicated that the reaction between DCF and Fe(VI) followed first-order kinetics with respect to each reactant. Furthermore, the effects of pH and temperature on DCF oxidation by Fe(VI) were elucidated using a systematic examination. The apparent second-order rate constants (kapp) increased significantly from 2.54 to 11.6M(-1)s(-1), as the pH of the solution decreased from 11.0 to 7.0, and the acid-base equilibriums of Fe(VI) and DCF were proposed to explain the pH dependence of kapp. The acute toxicity of DCF solution during Fe(VI) oxidation was evaluated using a Microtox bioassay. Overall, the DCF degradation process resulted in a rapid increase of the inhibition rate of luminescent bacteria. These toxicity tests suggest that the formation of enhanced toxic intermediates during the Fe(VI) disinfection process may pose potential health risk to consumers. Copyright © 2014 Elsevier B.V. All rights reserved.

[Mechanism and promotion effect of K+ on yield of Fe(VI)].

PubMed

Zhang, Yan-Ping; Xu, Guo-Ren; Li, Gui-Bai

2008-03-01

The mechanism and promotion effects of K+ on the yield of Fe(VI) were studied during the reaction of forming ferrate. The experiment results showed that K+ is far better than Na+ for the preparation of Fe(VI) at temperatures higher than 50 degrees C. The optimal temperature for the preparation of Fe(VI) with K+ is 65 degrees C. During the reaction, the yield of ferrate increases with the concentration of K+, and the promotion effect of K+ is obviously with ferric nitrate dosage increase. The Fe(VI) concentration prepared with 4.4 mol/L KOH is 0.05 mol/L at 85 g/L ferric nitrate; and which achieves 0.15 mol/L when added 2 mol/L K+. The promotion effect of K+ on the yield of ferrate is remarkable when ferric nitrate dosage is higher than 75 g/L, reaction temperature is below 55 degrees C and ClO(-) concentration is lower than 1.16 mol/L. The K+ can substitute for partly alkalinity and reduce the concentration of OH(-) in the reaction solution. During the reaction, the K+ can enwrap around FeO4(2-) that can reduce the contact between Fe(3+) and FeO4(2-), and decrease the catalysis effect of Fe(3+) on FeO4(2-). At the same time, K+ can react with FeO4(2-) to form solid K4FeO4, whichwill lower the Fe(VI) concentration, decrease the decomposition rate of Fe(VI), enhance the stability and improve the yield of Fe(VI).

Clinical and serological responses following primary and booster immunization with Salmonella typhi Vi capsular polysaccharide vaccines.

PubMed

Keitel, W A; Bond, N L; Zahradnik, J M; Cramton, T A; Robbins, J B

1994-01-01

Clinical and serum antibody responses following intramuscular injection of two formulations of Salmonella typhi Vi capsular polysaccharide (Vi) were assessed in a double-blind evaluation. Healthy adults were randomly assigned to receive a 25 micrograms dose of liquid (Vi-Liq; n = 182) or freeze-dried Vi vaccine (Vi-Lyoph; n = 55), or placebo (n = 86). Erythema and/or induration > or = 1 cm in diameter at the injection site developed in 13/182 (7%) of Vi-Liq and 3/55 (5%) of Vi-Lyoph recipients (not significant, n.s.). Fever (oral temperature > or = 100 degrees F (37.8 degrees C)) occurred in < 2% of vaccinees. The frequencies of rises of fourfold or greater and of maximal Vi antibody levels were similar in the two vaccine groups. Fourfold or greater rises in serum Vi antibody levels (RIA) developed in 53% of Vi-Lyoph and 60% of Vi-Liq recipients by 1 week (n.s.), and 98 and 93%, respectively, by 1 month (n.s.). The frequencies of adverse reactions and mean Vi antibody levels following booster immunization with Vi-Liq 27 to 34 months after primary immunization (n = 55) were similar to those observed following primary immunization, although subjects given a booster dose were more likely to develop local reactions > or = 1 cm in diameter than those given a first dose (10/55 versus 13/182, p = 0.013 by the chi 2 test). Primary and booster immunizations with the Vi vaccines are well tolerated in healthy adults; mean Vi antibody levels remain significantly elevated for up to 34 months after primary immunization.

Application of a surfactant-assisted dispersive liquid-liquid microextraction method along with central composite design for micro-volume based spectrophotometric determination of low level of Cr(VI) ions in aquatic samples.

PubMed

Sobhi, Hamid Reza; Azadikhah, Efat; Behbahani, Mohammad; Esrafili, Ali; Ghambarian, Mahnaz

2018-05-09

A fast, simple, low cost surfactant-assisted dispersive liquid-liquid microextraction method along with central composite design for the determination of low level of Cr(VI) ions in several aquatic samples has been developed. Initially, Cr(VI) ions present in the aqueous sample were readily reacted with 1,5‑diphenylcarbazide (DPC) in acidic medium through complexation. Sodium dodecyl sulfate (SDS), as an anionic surfactant, was then employed as an ion-pair agent to convert the cationic complex into the neutral one. Following on, the whole aqueous phase underwent a dispersive liquid-liquid microextraction (DLLME) leading to the transfer of the neutral complex into the fine droplet of organic extraction phase. A micro-volume spectrophotometer was used to determine Cr(VI) concentrations. Under the optimized conditions predicted by the statistical design, the limit of quantification (LOQ) obtained was reported to be 5.0 μg/L, and the calibration curve was linear over the concentration range of 5-100 μg/L. Finally, the method was successfully implemented for the determination of low levels of Cr(VI) ions in various real aquatic samples and the accuracies fell within the range of 83-102%, while the precision varied in the span of 1.7-5.2%. Copyright © 2018. Published by Elsevier B.V.

Methods for Estimating Adsorbed Uranium(VI) and Distribution Coefficients of Contaminated Sediments

USGS Publications Warehouse

Kohler, M.; Curtis, G.P.; Meece, D.E.; Davis, J.A.

2004-01-01

Assessing the quantity of U(VI) that participates in sorption/desorption processes in a contaminated aquifer is an important task when investigating U migration behavior. U-contaminated aquifer sediments were obtained from 16 different locations at a former U mill tailings site at Naturita, CO (U.S.A.) and were extracted with an artificial groundwater, a high pH sodium bicarbonate solution, hydroxylamine hydrochloride solution, and concentrated nitric acid. With an isotopic exchange method, both a KD value for the specific experimental conditions as well as the total exchangeable mass of U(VI) was determined. Except for one sample, KD values determined by isotopic exchange with U-contaminated sediments that were in equilibrium with atmospheric CO2 agreed within a factor of 2 with KD values predicted from a nonelectrostatic surface complexation model (NEM) developed from U(VI) adsorption experiments with uncontaminated sediments. The labile fraction of U(VI) and U extracted by the bicarbonate solution were highly correlated (r2 = 0.997), with a slope of 0.96 ?? 0.01. The proximity of the slope to one suggests that both methods likely access the same reservoir of U(VI) associated with the sediments. The results indicate that the bicarbonate extraction method is useful for estimating the mass of labile U(VI) in sediments that do not contain U(IV). In-situ KD values calculated from the measured labile U(VI) and the dissolved U(VI) in the Naturita alluvial aquifer agreed within a factor of 3 with in-situ K D values predicted with the NEM and groundwater chemistry at each well.

The effect of Si and Al concentrations on the removal of U(VI) in the alkaline conditions created by NH3 gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katsenovich, Yelena P.; Cardona, Claudia; Lapierre, Robert

2016-10-01

Remediation of uranium in the deep unsaturated zone is a challenging task, especially in the presence of oxygenated, high-carbonate alkalinity soil and pore water composition typical for arid and semi-arid environments of the western regions of the U.S. This study evaluates the effect of various pore water constituencies on changes of uranium concentrations in alkaline conditions, created in the presence of reactive gases such as NH3 to effectively mitigate uranium contamination in the vadose zone sediments. This contaminant is a potential source for groundwater pollution through slow infiltration of soluble and highly mobile uranium species towards the water table. Themore » objective of this research was to evaluate uranium sequestration efficiencies in the alkaline synthetic pore water solutions prepared in a broad range of Si, Al, and bicarbonate concentrations typically present in field systems of the western U.S. regions and identify solid uranium-bearing phases that result from ammonia gas treatment. In previous studies (Szecsody et al. 2012; Zhong et al. 2015), although uranium mobility was greatly decreased, solid phases could not be identified at the low uranium concentrations in field-contaminated sediments. The chemical composition of the synthetic pore water used in the experiments varied for silica (5–250 mM), Al3+ (2.8 or 5 mM), HCO3- (0–100 mM) and U(VI) (0.0021–0.0084 mM) in the solution mixture. Experiment results suggested that solutions with Si concentrations higher than 50 mM exhibited greater removal efficiencies of U(VI). Solutions with higher concentrations of bicarbonate also exhibited greater removal efficiencies for Si, Al, and U(VI). Overall, the silica polymerization reaction leading to the formation of Si gel correlated with the removal of U(VI), Si, and Al from the solution. If no Si polymerization was observed, there was no U removal from the supernatant solution. Speciation modeling indicated that the dominant uranium

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

USGS Publications Warehouse

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).

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

PubMed

Martins, Mónica; Faleiro, Maria Leonor; da Costa, Ana M Rosa; Chaves, Sandra; Tenreiro, Rogério; Matos, António Pedro; Costa, Maria Clara

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. Copyright © 2010 Elsevier B.V. All rights reserved.

The WMO RA VI Regional Climate Centre Network - a support to users in Europe

NASA Astrophysics Data System (ADS)

Rösner, S.

2012-04-01

deliver better climate services to national users. On 1 June 2009 the WMO RA VI Pilot RCC-Network started its pilot phase to demonstrate its capability to provide, on an operational day-to-day basis, the products agreed upon by the member countries of RA VI. On 5 October 2011 the process to become formally designated WMO RA VI RCC-Network was initiated, and it is expected that the designation will happen mid to end 2012. The presentation will describe the global and regional activities related to RCCs and explain in more details the situation in WMO RA VI (Europe).

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

PubMed

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.

Oxidation of Sulfonamides in Aqueous Solution by UV-TiO2-Fe(VI).

PubMed

Ma, Yan; Zhang, Kejia; Li, Cong; Zhang, Tuqiao; Gao, Naiyun

2015-01-01

The photocatalytic degradation of sulfonamides in aqueous TiO2 suspension under UV irradiation has been investigated using potassium ferrate as electron acceptors. The results showed that the stability of Fe(VI) is dependent on pH significantly, and the stability reduces obviously in the presence of UV-TiO2. The experiments indicated that Fe(VI) could effectively scavenge the conduction band electrons from the surface of TiO2. The photocatalytic oxidation of sulfonamides with Fe(VI) was found to be much faster than that without Fe(VI). The SD, SM, and SMX concentration was greatly reduced by 89.2%, 83.4%, and 82.0%, respectively, after 10 min with UV-TiO2-Fe(VI), comparing to 65.2%, 66.0%, and 71.9%, respectively, with Fe(VI) only in the dark and 71.3%, 72.7%, and 76.0%, respectively, with UV-TiO2. The pH value of solution significantly influenced the sulfonamides degradation in UV-TiO2-Fe(VI) system. The degradation amount of sulfonamides after 10 min was a maximum at pH 7. The intermediate products of sulfonamides oxidation by UV-TiO2-Fe(VI) were analysed by LC-HESI-MS-MS and the results suggested that a majority of sulfonamides turned into large-molecule products without complete mineralization.

Oxidation of Sulfonamides in Aqueous Solution by UV-TiO2-Fe(VI)

PubMed Central

Ma, Yan; Zhang, Kejia; Li, Cong; Zhang, Tuqiao; Gao, Naiyun

2015-01-01

The photocatalytic degradation of sulfonamides in aqueous TiO2 suspension under UV irradiation has been investigated using potassium ferrate as electron acceptors. The results showed that the stability of Fe(VI) is dependent on pH significantly, and the stability reduces obviously in the presence of UV-TiO2. The experiments indicated that Fe(VI) could effectively scavenge the conduction band electrons from the surface of TiO2. The photocatalytic oxidation of sulfonamides with Fe(VI) was found to be much faster than that without Fe(VI). The SD, SM, and SMX concentration was greatly reduced by 89.2%, 83.4%, and 82.0%, respectively, after 10 min with UV-TiO2-Fe(VI), comparing to 65.2%, 66.0%, and 71.9%, respectively, with Fe(VI) only in the dark and 71.3%, 72.7%, and 76.0%, respectively, with UV-TiO2. The pH value of solution significantly influenced the sulfonamides degradation in UV-TiO2-Fe(VI) system. The degradation amount of sulfonamides after 10 min was a maximum at pH 7. The intermediate products of sulfonamides oxidation by UV-TiO2-Fe(VI) were analysed by LC-HESI-MS-MS and the results suggested that a majority of sulfonamides turned into large-molecule products without complete mineralization. PMID:26347888

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

PubMed

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.

Disruption of Putrescine Biosynthesis in Shewanella oneidensis Enhances Biofilm Cohesiveness and Performance in Cr(VI) Immobilization

PubMed Central

Ding, Yuanzhao; Peng, Ni; Du, Yonghua; Ji, Lianghui

2014-01-01

Although biofilm-based bioprocesses have been increasingly used in various applications, the long-term robust and efficient biofilm performance remains one of the main bottlenecks. In this study, we demonstrated that biofilm cohesiveness and performance of Shewanella oneidensis can be enhanced through disrupting putrescine biosynthesis. Through random transposon mutagenesis library screening, one hyperadherent mutant strain, CP2-1-S1, exhibiting an enhanced capability in biofilm formation, was obtained. Comparative analysis of the performance of biofilms formed by S. oneidensis MR-1 wild type (WT) and CP2-1-S1 in removing dichromate (Cr2O72−), i.e., Cr(VI), from the aqueous phase showed that, compared with the WT biofilms, CP2-1-S1 biofilms displayed a substantially lower rate of cell detachment upon exposure to Cr(VI), suggesting a higher cohesiveness of the mutant biofilms. In addition, the amount of Cr(III) immobilized by CP2-1-S1 biofilms was much larger, indicating an enhanced performance in Cr(VI) bioremediation. We further showed that speF, a putrescine biosynthesis gene, was disrupted in CP2-1-S1 and that the biofilm phenotypes could be restored by both genetic and chemical complementations. Our results also demonstrated an important role of putrescine in mediating matrix disassembly in S. oneidensis biofilms. PMID:24362428

Chlorine decay and trihalomethane formation following ferrate(VI) preoxidation and chlorination of drinking water.

PubMed

Li, Cong; Luo, Feng; Dong, Feilong; Zhao, Jingguo; Zhang, Tuqiao; He, Guilin; Cizmas, Leslie; Sharma, Virender K

2017-11-01

This paper presents the effect of preoxidation with ferrate(VI) (Fe VI O 4 2- , Fe(VI)) prior to chlorination on chlorine decay and formation of disinfection by-products in filtered raw water from a full-scale drinking water treatment plant. The rate of chlorine decay became significantly faster as the concentration of ferrate(VI) increased. Chlorine degradation followed two first-order decay reactions with rate constants k 1 and k 2 for fast and slow decay, respectively. Kinetic modeling established the relationships between k 1 and k 2 and varying dosages of chlorine and ferrate(VI). When ferrate(VI) was used as a pre-oxidant, the levels of trihalomethanes (trichloromethane (TCM), dichlorobromomethane (DCBM), dibromochloromethane (DBCM), and tribromomethane (TBM)) in water samples decreased as the ferrate(VI) concentration increased. The concentrations of these trihalomethanes followed the order TCM > DCBM ≈ DBCM > TBM. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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 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.

23 CFR 200.11 - Procedures for processing Title VI reviews.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Procedures for processing Title VI reviews. 200.11 Section 200.11 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.11 Procedures for processing Title...

23 CFR 200.11 - Procedures for processing Title VI reviews.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Procedures for processing Title VI reviews. 200.11 Section 200.11 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.11 Procedures for processing Title...

23 CFR 200.11 - Procedures for processing Title VI reviews.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Procedures for processing Title VI reviews. 200.11 Section 200.11 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.11 Procedures for processing Title...

23 CFR 200.11 - Procedures for processing Title VI reviews.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Procedures for processing Title VI reviews. 200.11 Section 200.11 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.11 Procedures for processing Title...

Thermodynamic Insight into the Solvation and Complexation Behavior of U(VI) in Ionic Liquid: Binding of CMPO with U(VI) Studied by Optical Spectroscopy and Calorimetry.

PubMed

Wu, Qi; Sun, Taoxiang; Meng, Xianghai; Chen, Jing; Xu, Chao

2017-03-06

The complexation of U(VI) with octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO, denoted as L) in ionic liquid (IL) C 4 mimNTf 2 was investigated by UV-vis absorption spectrophotometry and isothermal titration calorimetry. Spectro-photometric titration suggests that three successive complexes, UO 2 L j 2+ (j = 1-3), formed both in "dry" (water content < 250 ppm) and "wet" (water content ≈ 12 500 ppm) ionic liquid. However, the thermodynamic parameters are distinctly different in the two ILs. In dry IL, the complexation strength between CMPO and U(VI) is much stronger, with stability constants of the respective complexes more than 1 order of magnitude higher than that in wet IL. Energetically, the complexation of U(VI) with CMPO in dry IL is mainly driven by negative enthalpies. In contrast, the complexation in wet IL is overwhelmingly driven by highly positive entropies as a result of the release of a large amount of water molecules from the solvation sphere of U(VI). Moreover, comparisons between the fitted absorption spectra of complexes in wet IL and that of extractive samples from solvent extraction have identified the speciation involved in the extraction of U(VI) by CMPO in ionic liquid. The results from this study not only offer a thermodynamic insight into the complexation behavior of U(VI) with CMPO in IL but also provide valuable information for understanding the extraction behavior in the corresponding solvent extraction system.

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

PubMed

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.

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

PubMed Central

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

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

PubMed

Estokova, Adriana; Palascakova, Lenka; Kanuchova, Maria

2018-04-22

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.

Heptavalent Neptunium in a Gas-Phase Complex: (Np VIIO 3 +)(NO 3 –) 2

DOE PAGES

Dau, Phuong D.; Maurice, Remi; Renault, Eric; ...

2016-09-15

A central goal of chemistry is to achieve ultimate oxidation states, including in gas-phase complexes with no condensed phase perturbations. In the case of the actinide elements, the highest established oxidation states are labile Pu(VII) and somewhat more stable Np(VII). We have synthesized and characterized gas-phase AnO 3(NO 3) 2- complexes for An = U, Np, and Pu by endothermic NO 2 elimination from AnO 2(NO 3) 3-. It was previously demonstrated that the PuO 3+ core of PuO 3(NO 3) 2- has a Pu—O• radical bond such that the oxidation state is Pu(VI); it follows that in UO 3(NOmore » 3) 2- it is the stable U(VI) oxidation state. On the basis of the relatively more facile synthesis of NpO 3(NO 3) 2-, a Np(VII) oxidation state is inferred. This interpretation is substantiated by reactivity of the three complexes: NO 2 spontaneously adds to UO 3(NO 3) 2- and PuO 3(NO 3) 2- but not to NpO 3(NO 3) 2-. This unreactive character is attributed to a Np(VII)O 3+ core with three stable Np=O bonds, this in contrast to reactive U—O• and Pu—O• radical bonds. The computed structures and reaction energies for the three AnO 3(NO 3) 2- support the conclusion that the oxidation states are U(VI), Np(VII), and Pu(VI). These results establish the extreme Np(VII) oxidation state in a gas-phase complex, and demonstrate the inherently greater stability of Np(VII) versus Pu(VII).« less

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

PubMed

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.

Probing chromium(III) from chromium(VI) in cells by a fluorescent sensor

NASA Astrophysics Data System (ADS)

Hu, Xiangquan; Chai, Jie; Liu, Yanfei; Liu, Bin; Yang, Binsheng

2016-01-01

Cellular uptake of Cr(VI), followed by its reduction to Cr(III) with the formation of kinetically inert Cr(III) complexes, is a complex process. To better understand its physiological and pathological functions, efficient methods for the monitoring of Cr(VI) are desired. In this paper a selective fluorescent probe L, rhodamine hydrazide bearing a benzo[b]furan-2-carboxaldehyde group, was demonstrated as a red chemosensor for Cr(III) at about 586 nm. This probe has been used to probe Cr(III) which is reduced from Cr(VI) by reductants such as glutathione (GSH), vitamin C, cysteine (Cys), H2O2 and Dithiothreitol (DTT) by fluorescence spectra. Cr(VI) metabolism in vivo is primarily driven by Vc and GSH. Vc could reduce CrO42 - to Cr(III) in a faster rate than GSH. The indirectly detection limit for Cr(VI) by L + GSH system was determined to be 0.06 μM at pH = 6.2. Moreover, the confocal microscopy image experiments indicated that Cr(VI) can be reduced to Cr(III) inside cells rapidly and the resulted Cr(III) can be captured and imaged timely by L.

VI-14, a novel flavonoid derivative, inhibits migration and invasion of human breast cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Fanni; Li, Chenglin; Zhang, Haiwei

It has been well characterized that flavonoids possess pronounced anticancer potentials including anti-angiogenesis, anti-metastasis, and pro-apoptosis. Herein, we report, for the first time, that VI-14, a novel flavonoid derivative, possesses anti-cancer properties. The purpose of this study is to investigate the anti-migration and anti-invasion activities of VI-14 in breast cancer cells. Our data indicate that VI-14 inhibits adhesion, migration and invasion of MDA-MB-231 and MDA-MB-435 human breast cancer cells. MDA-MB-231 cells treated with VI-14 display reduced activities and expressions of ECM degradation-associated proteins including matrix metalloproteinase 2 (MMP-2) and 9 (MMP-9) at both the protein and mRNA levels. Meanwhile, VI-14more » treatment induces an up-regulated expression of tissue inhibitor of metalloproteinase 1 (TIMP-1) and 2 (TIMP-2) in MDA-MB-231 cells. Western blotting results show that phosphorylation levels of critical components of the MAPK signaling pathway, including ERK, JNK and P38, are dramatically decreased in VI-14-treated MDA-MB-231 cells. Furthermore, treatment of VI-14 significantly decreases the nuclear levels and the binding ability of nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1). Taken together, our data suggest that VI-14 treatment suppresses migration and motility of breast cancer cells, and VI-14 may be a potential compound for cancer therapy. Highlights: ► We report for the first time that VI-14 possesses anti-cancer properties. ► VI-14 weakens the adhesion, migration and invasion of human breast cancer cells. ► VI-14 decreases the activities and expressions of MMP-2/9. ► VI-14 suppresses the phosphorylation levels of the MAPK signaling pathway. ► VI-14 decreases the nuclear levels and the binding ability of NF-κB and AP-1.« less

AM(VI) partitioning studies. FY14 final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mincher, Bruce J.

2014-10-01

The use of higher oxidation states of americium in partitioning from the lanthanides is under continued investigation by the sigma team. This is based on the hypothesis that Am(VI) can be produced and remain stable in irradiated first cycle raffinate solution long enough to perform solvent extraction for separations. The stability of Am(VI) to autoreduction was measured using millimolar americium concentrations in a 1-cm cell with a Cary 6000 UV/Vis spectrophotometer for data acquisition. At millimolar americium concentrations, Am(VI) is stable enough against its own autoreduction for separations purposes. A second major accomplishment during FY14 was the hot test. Americiummore » oxidation and extraction was performed using a centrifugal contactor-based test bed consisting of an extraction stage and two stripping stages. Sixty-three percent americium extraction was obtained in one extraction stage, in agreement with batch contacts. Promising electrochemical oxidation results have also been obtained, using terpyridine ligand derivatized electrodes for binding of Am(III). Approximately 50 % of the Am(III) was oxidized to Am(V) over the course of 1 hour. It is believed that this is the first demonstration of the electrolytic oxidation of americium in a non-complexing solution. Finally, an initial investigation of Am(VI) extraction using diethylhexylbutyramide (DEHBA) was performed.« less

Reaction kinetics and oxidation product formation in the degradation of acetaminophen by ferrate (VI).

PubMed

Wang, Hongyu; Liu, Yibing; Jiang, Jia-Qian

2016-07-01

This paper investigates the degradation of acetaminophen (AAP) in aqueous solutions by ferrate (VI), aiming to propose the kinetics, pathways and the oxidation products' formation in the AAP degradation. A series of jar tests were undertaken over ferrate (VI) dosages (molar ratios of ferrate (VI):AAP, 5:1 to 25:1) and pH values (4-11). The effects of co-existing ions (0.2-5 mM) and humic acid (10-50 mg l(-1)) on the AAP removal were investigated. Ferrate (VI) can remove 99.6% AAP (from 1000 μg l(-1)) in 60 min under study conditions when majority of the AAP reduction occurred in the first 5 min. The treatment performance depended on the ferrate(VI) dosage, pH and the type and strength of co-existing ions and humic acid. Raising ferrate (VI) dosage with optimal pH 7 improved the AAP degradation. In the presence of humic acid, the AAP degradation by ferrate (VI) was promoted in a short period (<30 min) but then inhibited with increasing in humic acid contents. The presence of Al(3+), CO3(2-) and PO4(3-) ions declined but the existence of K(+), Na(+), Mg(2+) and Ca(2+) ions can improve the AAP removal. The catalytic function of Al(3+) on the decomposition of ferrate (VI) in aqueous solution was found. The kinetics of the reaction between ferrate (VI) and AAP was pseudo first-order for ferrete (VI) and pseudo second-order for AAP. The pseudo rate constant of ferrate (VI) with AAP was 1.4 × 10(-5) L(2) mg(-2) min(-1). Three oxidation products (OPs) were identified and the AAP degradation pathways were proposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Group I-III-VI.sub.2 semiconductor films for solar cell application

DOEpatents

Basol, Bulent M.; Kapur, Vijay K.

1991-01-01

This invention relates to an improved thin film solar cell with excellent electrical and mechanical integrity. The device comprises a substrate, a Group I-III-VI.sub.2 semiconductor absorber layer and a transparent window layer. The mechanical bond between the substrate and the Group I-III-VI.sub.2 semiconductor layer is enhanced by an intermediate layer between the substrate and the Group I-III-VI.sub.2 semiconductor film being grown. The intermediate layer contains tellurium or substitutes therefor, such as Se, Sn, or Pb. The intermediate layer improves the morphology and electrical characteristics of the Group I-III-VI.sub.2 semiconductor layer.

On the Stark broadening of Cr VI spectral lines in astrophysical plasma

NASA Astrophysics Data System (ADS)

Dimitrijević, M. S.; Simić, Z.; Sahal-Bréchot, S.

2017-02-01

Stark broadening parameters for Cr VI lines have been calculated using semiclassical perturbation method for conditions of interest for stellar plasma. Here are presented, as an example of obtained results, Stark broadening parameters for electron- and proton-impact broadening for Cr VI 4s 2S-4p 2P° λ = 1430 Å and Cr VI 4p 2P°-5s 2S λ = 611.8 Å multiplets. The obtained results are used to demonstrate the importance of Stark broadening of Cr VI in DO white dwarf atmospheres. Also the obtained results will enter in STARK-B database which is included in Virtual Atomic and Molecula Data Center - VAMDC.

Diffusion of U(VI) in Opalinus Clay: Influence of temperature and humic acid

NASA Astrophysics Data System (ADS)

Joseph, C.; Van Loon, L. R.; Jakob, A.; Steudtner, R.; Schmeide, K.; Sachs, S.; Bernhard, G.

2013-05-01

The diffusion of U(VI) (c0 = 1 × 10-6 mol/L) in compacted Opalinus Clay from the Mont Terri underground laboratory, Switzerland, was studied in the absence and presence of humic acid (10 mg/L) at two different temperatures (25 °C, 60 °C) under anaerobic conditions. As background electrolyte synthetic Opalinus Clay pore water (pH 7.6, I = 0.36 mol/L) was used. The diffusion-accessible porosity, ɛ, was determined for each Opalinus Clay bore core sample by through-diffusion experiments with tritiated water (HTO) before the U(VI) diffusion experiments were carried out. The values for the effective diffusion and distribution coefficients De and Kd obtained for U(VI) and humic acid at 25 °C as well as at 60 °C showed that humic acid has no significant influence on the U(VI) diffusion. The diffusion profiles of humic acid in Opalinus Clay at 25 and 60 °C indicate the contributions of two different humic acid particle size fractions (<1 kDa and 10-100 kDa). The small-sized humic acid fraction diffused through the whole Opalinus Clay samples at both temperatures within the 3 month duration of the U(VI) diffusion experiments. At 60 °C, diffusion profiles of two different U(VI) species were observed. In a separate experiment the U(VI) speciation in the source reservoir solution at 60 °C was analyzed by laser-induced fluorescence spectroscopy, photon correlation spectroscopy and scanning electron microscopy with an energy dispersive X-ray detector. The two diffusion profiles could be attributed to an unknown colloidal and a known aquatic U(VI) species (Ca2UO2(CO3)3(aq)). The diffusion results showed that the interaction of U(VI) and of the large-sized humic acid colloid fraction with the clay is stronger at 60 °C. An increase of Kd from 0.025 ± 0.003 m3/kg at 25 °C to 0.25 ± 0.05 m3/kg for U(VI)colloidal at 60 °C was determined. In addition, the value for De of U(VI) increased with increasing temperature. Using the De values at 25 and 60 °C, a preliminary

Optimizing Cr(VI) and Tc(VII) remediation through nano-scale biomineral engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cutting, R. S.; Coker, V. S.; Telling, N. D.

2009-09-09

To optimize the production of biomagnetite for the bioremediation of metal oxyanion contaminated waters, the reduction of aqueous Cr(VI) to Cr(III) by two biogenic magnetites and a synthetic magnetite was evaluated under batch and continuous flow conditions. Results indicate that nano-scale biogenic magnetite produced by incubating synthetic schwertmannite powder in cell suspensions of Geobacter sulfurreducens is more efficient at reducing Cr(VI) than either biogenic nano-magnetite produced from a suspension of ferrihydrite 'gel' or synthetic nano-scale Fe{sub 3}O{sub 4} powder. Although X-ray Photoelectron Spectroscopy (XPS) measurements obtained from post-exposure magnetite samples reveal that both Cr(III) and Cr(VI) are associated with nanoparticlemore » surfaces, X-ray Magnetic Circular Dichroism (XMCD) studies indicate that some Cr(III) has replaced octahedrally coordinated Fe in the lattice of the magnetite. Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) measurements of total aqueous Cr in the associated solution phase indicated that, although the majority of Cr(III) was incorporated within or adsorbed to the magnetite samples, a proportion ({approx}10-15 %) was released back into solution. Studies of Tc(VII) uptake by magnetites produced via the different synthesis routes also revealed significant differences between them as regards effectiveness for remediation. In addition, column studies using a {gamma}-camera to obtain real time images of a {sup 99m}Tc(VII) radiotracer were performed to visualize directly the relative performances of the magnetite sorbents against ultra-trace concentrations of metal oxyanion contaminants. Again, the magnetite produced from schwertmannite proved capable of retaining more ({approx}20%) {sup 99m}Tc(VII) than the magnetite produced from ferrihydrite, confirming that biomagnetite production for efficient environmental remediation can be fine-tuned through careful selection of the initial Fe(III) mineral

ESL VI Curriculum Guide.

ERIC Educational Resources Information Center

Flander, Leonard

This curriculum guide for English as a Second Language (ESL) Level VI is the sixth of six in a Guam Community College ESL project series. The other five guides, a companion teacher's guide and pre- and post-tests are available separately (see note). The entire project centers around the Peabody Kits P, Level P, Level 1, Level 2, Level 3, and the…

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

PubMed

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

NASA Astrophysics Data System (ADS)

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.

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

PubMed

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

NASA Astrophysics Data System (ADS)

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

A Salmonella Typhimurium-Typhi Genomic Chimera: A Model to Study Vi Polysaccharide Capsule Function In Vivo

PubMed Central

Clare, Simon; Goulding, David; Holt, Kathryn E.; Grant, Andrew J.; Mastroeni, Piero; Dougan, Gordon; Kingsley, Robert A.

2011-01-01

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. PMID:21829346

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

NASA Astrophysics Data System (ADS)

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.

Aqueous solubility of Cr(VI) compounds in ferrochrome bag filter dust and the implications thereof

DOE PAGES

Du Preez, S. P.; Beukes, J. P.; Van Dalen, W. P. J.; ...

2017-04-21

The production of ferrochrome (FeCr) is a reducing process. However, it is impossible to completely exclude oxygen from all of the high-temperature production process steps, which may lead to unintentional formation of small amounts of Cr(VI). The majority of Cr(VI) is associated with particles found in the off-gas of the high-temperature processes, which are cleaned by means of venturi scrubbers or bag filter dust (BFD) systems. BFD contains the highest concentration of Cr(VI) of all FeCr wastes. In this study, the solubility of Cr(VI) present in BFD was determined by evaluating four different BFD samples. The results indicate that themore » currently applied Cr(VI) treatment strategies of the FeCr producer (with process water pH ≤ 9) only effectively extract and treat the water-soluble Cr(VI) compounds, which merely represented approximately 31% of the total Cr(VI) present in the BFD samples evaluated. Extended extraction time, within the afore-mentioned pH range, proved futile in extracting sparingly-soluble and water-insoluble Cr(VI) species, which represented approximately 34% and 35% of the total Cr(VI), respectively. Due to the deficiencies of the current treatment strategies, it is highly likely that sparingly water-soluble Cr(VI) compounds will leach from waste storage facilities (e.g. slimes dams) over time. Therefore, it is critical that improved Cr(VI) treatment strategies be formulated, which should be an important future perspective for FeCr producers and researchers alike.« less

Simultaneous determination of asperosaponin VI and its active metabolite hederagenin in rat plasma by liquid chromatography-tandem mass spectrometry with positive/negative ion-switching electrospray ionization and its application in pharmacokinetic study.

PubMed

Zhu, He; Ding, Li; Shakya, Shailendra; Qi, Xiemin; Hu, Linlin; Yang, Xiaolin; Yang, Zhonglin

2011-11-15

A new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method operated in the positive/negative electrospray ionization (ESI) switching mode has been developed and validated for the simultaneous determination of asperosaponin VI and its active metabolite hederagenin in rat plasma. After addition of internal standards diazepam (for asperosaponin VI) and glycyrrhetic acid (for hederagenin), the plasma sample was deproteinized with acetonitrile, and separated on a reversed phase C18 column with a mobile phase of methanol (solvent A)-0.05% glacial acetic acid containing 10 mM ammonium acetate and 30 μM sodium acetate (solvent B) using gradient elution. The detection of target compounds was done in multiple reaction monitoring (MRM) mode using a tandem mass spectrometry equipped with positive/negative ion-switching ESI source. At the first segment, the MRM detection was operated in the positive ESI mode using the transitions of m/z 951.5 ([M+Na](+))→347.1 for asperosaponin VI and m/z 285.1 ([M+H](+))→193.1 for diazepam for 4 min, then switched to the negative ESI mode using the transitions of m/z 471.3 ([M-H](-))→471.3 for hederagenin and m/z 469.4 ([M-H](-))→425.4 for glycyrrhetic acid, respectively. The sodiated molecular ion [M+Na](+) at m/z 951.5 was selected as the precursor ion for asperosaponin VI, since it provided better sensitivity compared to the deprotonated and protonated molecular ions. Sodium acetate was added to the mobile phase to make sure that abundant amount of the sodiated molecular ion of asperosaponin VI could be produced, and more stable and intensive mass response of the product ion could be obtained. For the detection of hederagenin, since all of the mass responses of the fragment ions were very weak, the deprotonated molecular ion [M-H](-)m/z 471.3 was employed as both the precursor ion and the product ion. But the collision energy was still used for the MRM, in order to eliminate the influences induced by the interference

Chromium (VI) purification using pine sawdust in batch systems

NASA Astrophysics Data System (ADS)

Politi, Dorothea; Sidiras, Dimitris

2012-12-01

Pine sawdust, a waste generated in furniture industry, has been used as low-cost potential adsorbent. This low-cost adsorbent was used for the removal of chromium (VI) from an aqueous solution. The kinetics of adsorption and extent of adsorption at equilibrium are dependent on the physical and chemical characteristics of the adsorbent and adsorbate. The effect of hydrogen ion concentration, contact time, adsorbent dose and initial concentration of adsorbate on the uptake of chromium were studied in batch experiments. The adsorption data has been correlated with Lagergren - Eldridge pseudofirst order kinetic model. The efficiency of adsorbent material for the removal of Cr(VI) was found to be between 13.1 and 95.6%, respectively. These results depend on the conditions of pH, contact time, sawdust dose and Cr(VI) concentration.

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

USGS Publications Warehouse

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 < 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.

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

PubMed

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.

Remediation of chromium-slag leakage with electricity cogeneration via a urea-Cr(VI) cell

PubMed Central

Yu, Binbin; Zhang, Huimin; Xu, Wei; Li, Gang; Wu, Zucheng

2014-01-01

Chromium pollution has been historically widespread throughout the world. Most available remediation technologies often require energy consumption. This study is aimed to develop electrochemical remediation for Cr(VI) in chromium-slag leakage with self-generated electricity. Dynamic leaching experiments of chromium-slag samples were conducted to survey the release and leaching behavior of Cr(VI). Based on previous work, a unique urea-Cr(VI) was designed, in which urea was employed as the fuel and Cr(VI) from the leakage of the dichromate slag served as the oxidant. Furthermore, the electrochemical results showed that the removal percent of Cr(VI) was more than 96% after 18 h with the leakage Cr(VI) concentration of 2.69 mM. The open circuit potential (OCP) varied in the range of 1.56 ~ 1.59 V under different initial Cr(VI) leakage concentrations. The approach explores the feasibility of the promising technique without the need of energy input for simultaneous chromium-slag remediation and generation of electricity. PMID:25168513

Bacterial reduction of Cr(VI) at technical scale--the Malaysian experience.

PubMed

Zakaria, Zainul Akmar; Ahmad, Wan Azlina; Zakaria, Zainoha; Razali, Firdausi; Karim, Norsuhada Abdul; Sum, Mohamad Md; Sidek, Mohd Saufi Mohd

2012-07-01

The bacterial reduction of Cr(VI) from industrial wastewater was evaluated using a 2.0-m(3) bioreactor. Liquid pineapple waste was used as a nutrient for the biofilm community formed inside the bioreactor. The use of rubber wood sawdust as packing material was able to immobilize more than 10(6) CFU mL(-1) of Acinetobacter haemolyticus cells after 3 days of contact time. Complete reduction of 15-240 mg L(-1) of Cr(VI) was achieved even after 3 months of bioreactor operation. Cr(VI) was not detected in the final effluent fraction indicating complete removal of Cr from solution from the flocculation/coagulation step and the unlikely re-oxidation of Cr(III) into Cr(VI). Impatiens balsamina L. and Gomphrena globosa L. showed better growth in the presence of soil-sludge mixture compared to Coleus scutellarioides (L.) Benth. Significant amounts of Cr accumulated at different sections of the plants indicate its potential application in Cr phytoremediation effort. The bacterial-based system was also determined not to be detrimental to human health based on the low levels of Cr detected in the hair and nail samples of the plant operators. Thus, it can be said that bacterial-based Cr(VI) treatment system is a feasible alternative to the conventional system especially for lower Cr(VI) concentrations, where sludge generated can be used as growth supplement for ornamental plant as well as not detrimental to the health of the workers.

Fate of Adsorbed U(VI) during Sulfidization of Lepidocrocite and Hematite

PubMed Central

2017-01-01

The impact on U(VI) adsorbed to lepidocrocite (γ-FeOOH) and hematite (α-Fe2O3) was assessed when exposed to aqueous sulfide (S(-II)aq) at pH 8.0. With both minerals, competition between S(-II) and U(VI) for surface sites caused instantaneous release of adsorbed U(VI). Compared to lepidocrocite, consumption of S(-II)aq proceeded slower with hematite, but yielded maximum dissolved U concentrations that were more than 10 times higher, representing about one-third of the initially adsorbed U. Prolonged presence of S(-II)aq in experiments with hematite in combination with a larger release of adsorbed U(VI), enhanced the reduction of U(VI): after 24 h of reaction about 60–70% of U was in the form of U(IV), much higher than the 25% detected in the lepidocrocite suspensions. X-ray absorption spectra indicated that U(IV) in both hematite and lepidocrocite suspensions was not in the form of uraninite (UO2). Upon exposure to oxygen only part of U(IV) reoxidized, suggesting that monomeric U(IV) might have become incorporated in newly formed iron precipitates. Hence, sulfidization of Fe oxides can have diverse consequences for U mobility: in short-term, desorption of U(VI) increases U mobility, while reduction to U(IV) and its possible incorporation in Fe transformation products may lead to long-term U immobilization. PMID:28121137

Determination of free polysaccharide in Vi glycoconjugate vaccine against typhoid fever.

PubMed

Giannelli, C; Cappelletti, E; Di Benedetto, R; Pippi, F; Arcuri, M; Di Cioccio, V; Martin, L B; Saul, A; Micoli, F

2017-05-30

Glycoconjugate vaccines based on the Vi capsular polysaccharide directed against Salmonella enterica serovar Typhi are licensed or in development against typhoid fever, an important cause of morbidity and mortality in developing countries. Quantification of free polysaccharide in conjugate vaccines is an important quality control for release, to monitor vaccine stability and to ensure appropriate immune response. However, we found that existing separation methods based on size are not appropriate as free Vi non-specifically binds to unconjugated and conjugated protein. We developed a method based on free Vi separation by Capto Adhere resin and quantification by HPAEC-PAD. The method has been tested for conjugates of Vi derived from Citrobacter freundii with different carrier proteins such as CRM 197 , Tetanus Toxoid and Diphtheria Toxoid. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

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

PubMed Central

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

Chromium isotope variation along a contaminated groundwater plume: a coupled Cr(VI)- reduction, advective mixing perspective

NASA Astrophysics Data System (ADS)

Bullen, T.; Izbicki, J.

2007-12-01

Chromium (Cr) is a common contaminant in groundwater, used in electroplating, leather tanning, wood preservation, and as an anti-corrosion agent. Cr occurs in two oxidation states in groundwater: Cr(VI) is highly soluble and mobile, and is a carcinogen; Cr(III) is generally insoluble, immobile and less toxic than Cr(VI). Reduction of Cr(VI) to Cr(III) is thus a central issue in approaches to Cr(VI) contaminant remediation in aquifers. Aqueous Cr(VI) occurs mainly as the chromate (CrO22-) and bichromate (HCrO2-) oxyanions, while Cr(III) is mainly "hexaquo" Cr(H2O)63+. Cr has four naturally-occurring stable isotopes: 50Cr, 52Cr, 53Cr and 54Cr. When Cr(VI) is reduced to Cr(III), the strong Cr-O bond must be broken, resulting in isotopic selection. Ellis et al. (2002) demonstrated that for reduction of Cr(VI) on magnetite and in natural sediment slurries, the change of isotopic composition of the remnant Cr(VI) pool was described by a Rayleigh fractionation model having fractionation factor ɛCr(VI)-Cr(III) = 3.4‰. We attempted to use Cr isotopes as a monitor of Cr(VI) reduction at a field site in Hinkley, California (USA) where groundwater contaminated with Cr(VI) has been under assessment for remediation. Groundwater containing up to 5 ppm Cr(VI) has migrated down-gradient from the contamination source through the fluvial to alluvial sediments to form a well-defined plume. Uncontaminated groundwater in the aquifer immediately adjacent to the plume has naturally-occurring Cr(VI) of 4 ppb or less (CH2M-Hill). In early 2006, colleagues from CH2M-Hill collected 17 samples of groundwater from within and adjacent to the plume. On a plot of δ53Cr vs. log Cr(VI), the data array is strikingly linear and differs markedly from the trend predicted for reduction of Cr(VI) in the contaminated water. There appear to be two groups of data: four samples with δ53Cr >+2‰ and Cr(VI) <4 ppb, and 13 samples with δ53Cr <+2‰ and Cr(VI) >15 ppb. Simple mixing lines between the

Genetics Home Reference: glycoprotein VI deficiency

MedlinePlus

... protein called glycoprotein VI (GPVI). This protein is embedded in the outer membrane of blood cell fragments ... erythematosus (SLE). Autoimmune disorders occur when the immune system malfunctions and attacks the body's own cells and ...

Identification of Type VI Collagen Synthesizing Cells in Human Diabetic Glomerulosclerosis Using Renal Biopsy Sections

PubMed Central

Razzaque, Mohammed Shawkat; Koji, Takehiko; Harada, Takashi; Taguchi, Takashi

1997-01-01

Although the role of extracellular matrices in the development of glomerulosclerosis has been discussed widely, the cellular origin of type VI collagen in diabetic nephropathy (DN) has remained relatively unexplored. This study reports the distribution and cellular origin of type VI collagen in DN. Type VI collagen‐specific oligonucleotide probes and monoclonal antibody were used to assess the relative expression of mRNA for \\alpha1 (VI) chain and its translated protein in paraffin‐embedded renal biopsy sections of DN. By immunohistochemistry, compared to the control, increased deposition of type VI collagen was noted in the diffuse and nodular lesions of diabetic glomeruli. For cellular localization of type VI collagen mRNA, paraffin‐embedded renal sections of the control and DN were hybridized in situ with digoxigenin (Dig)‐labeled antisense oligo‐DNA probe complementary to a part of \\alpha1 (VI) mRNA. In comparison to the control kidney sections, increased numbers of intraglomerular cells (both mesangial and epithelial cells) were positive for α1 (VI) mRNA in renal biopsy sections of DN. From the results, we conclude that overexpression of type VI collagen by intraglomerular cells with its increased deposition might significantly contribute to the glomerulosclerosis found in DN. PMID:9497854

Final Technical Report -- GEO-VI - USGEO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirsch, Leonard

2009-11-30

Representatives of US earth observations departments and agencies, other participating governments, NGOs and civil society participated in the Sixth Plenary Meeting of the Group on Earth Observations (GEO-VI), hosted by the United States in Washington, DC on November 17 and 18, 2009. The meeting was held in the Atrium Ballroom of the Ronald Reagan International Trade Center. Exhibitions of international Earth observation technology and programs were held concurrently in the same venue. A number of GEO committee meetings and side events were held in conjunction with the GEO-VI Plenary, including the GEO-IGOS Symposium on Earth observation science and applications, themore » GEOSS in the Americas Forum on Coastal Zones, and separate meetings of the GEO Communities of Practice on Carbon, Health, and Air Quality.« less

Effect of potassium ferrate(VI) on survival and reproduction of Ichthyophthirius multifiliis tomonts.

PubMed

Ling, Fei; Wang, Jian-Guo; Wang, Gao-Xue; Gong, Xiao-Ning

2011-11-01

Ichthyophthirius multifiliis is an important freshwater teleost pathogen that can infect most species of freshwater fish worldwide and often leads to significant economic losses to the aquaculture industry. Potassium ferrate(VI), as a potential therapeutic agent for external protozoan parasite infections, has been proven to kill I. multifiliis theronts effectively; however, no information is available on effects of potassium ferrate(VI) exposure to I. multifiliis tomonts. This study evaluated the effects of potassium ferrate(VI) on the survival and reproduction of I. multifiliis tomonts. The results of experiment 1 showed that potassium ferrate(VI) at concentrations of 2.4, 4.8, 9.6, and 19.2 mg/L resulted in tomont survival rates of 82.2%, 34.2%, 14.6%, and 0, respectively, and significant differences were noted in tomont reproduction between the treatments and the control (P < 0.05). Additionally, this study was designed to determine the effect of potassium ferrate(VI) toxicity on age of the tomont. The results indicated that encysted I. multifiliis was more resistant to potassium ferrate(VI) treatments. In addition, this study was designed to investigate I. multifiliis tomont survival and reproduction when collected from infested goldfish in potassium ferrate(VI) solutions at different concentrations (0, 2.4, 4.8, 9.6, and 19.2 mg/L) for 30 min. It was found that the tomont survivals in the treatments were significantly lower than those in the control (P < 0.05). This study demonstrated that a bath with potassium ferrate(VI) possibly was an effective method to treat ichthyophthiriasis.

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

NASA Astrophysics Data System (ADS)

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

Prevalence of TMJ Disorders among the Patients Attending the Dental Clinic of Ajman University of Science and Technology-Fujairah Campus, UAE.

PubMed

AlShaban, Kashef K; Gul Abdul Waheed, Zainab

2018-01-01

The objective of this study was to determine the prevalence of temporomandibular joint (TMJ) disorders (if any) among the patients attending the dental clinic (for routine dental treatment) of Ajman University of Science and Technology (AUST)-Fujairah campus, UAE, and its possible causes. A sample of 100 adult patients attending the dental clinic of AUST for different types of dental treatment were collected; the routine examination of the TMJ and possible disorders such as clicking, crepitation, limitation or deviation during mouth opening, or tenderness reveals that 41% of the sample experience varying degrees of disorders in the TMJ. Radiographs were taken if needed (panoramic radiograph). The information was collected and recorded for each patient through questionnaires.

Dolomite Formation within Microbial Mats in the Sabkha of Abu Dhabi (UAE) and Associated Microsedimentary Structures

NASA Astrophysics Data System (ADS)

Bontognali, T. R.; Vasconcelos, C.; McKenzie, J. A.

2008-12-01

The link between microbial activity and dolomite formation has been evaluated in the coastal sabkha of Abu Dhabi (UAE). This modern dolomite-forming environment is frequently cited as the type analogue for the interpretation of many ancient evaporitic sequences. The investigation of sabkha sediments along a transect from intertidal to supratidal zones revealed a close association between microbial mats and dolomite. Authigenic dolomite occurs within surface and buried microbial mats, which are comprised of exopolymeric substances (EPS). Dolomite forms as a direct consequence of mineral nucleation and growth within microbially produced EPS. The cation-binding effect of the EPS molecules influences the composition of the precipitate. The early stage of this process is characterized by the complexation of an amorphous Mg-Si precipitate, which promotes dolomite development. Mineral formation within EPS appears to be enhanced by evaporation with consequent supersaturation of the pore waters with respect to dolomite. Partial EPS degradation during diagenesis may also provide an additional source of cations. However, the specific mineral-template property of EPS, rather than an increase in cation concentrations, is the key factor for dolomite formation in the studied area of the sabkha. Indeed, within the modern microbial mat located at the surface, dolomite precipitates from pore waters whose composition is very close to seawater. In the supratidal zone, pore water analysis and stable isotope values did not reveal any linkage between dolomite formation and microbial excretion and/or consumption of metabolites along the sediment profiles. This is in contrast with current models, in which dolomite formation is mainly linked to microbial increase of pH and alkalinity or consumption of dissolved SO4 in pore-waters. The EPS of the microbial mats is characterized by an alveolar microfabric, which can be mineralized during early diagenesis, preserving fossil imprints of the

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

USGS Publications Warehouse

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.

Osteogenesis Imperfecta Type VI in Individuals from Northern Canada.

PubMed

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.

Army Enlisted Personnel Competency Assessment Program: Phase 2 Report

DTIC Science & Technology

2006-01-01

benefit analysis of a notional Army program will be conducted. v Findings: The prototype Army core assessment was successfully administered to over 600...about competency assessment. They will also be incorporated into a cost and benefit analysis to be conducted in Phase III. vi CONTENTS Page Chapter 1...Conduct a Cost- Benefit Analysis, and Make System Recommendations Phase I of PerformM21 resulted in program design recommendations that included such

Flow injection for the determination of Se(IV) and Se(VI) by hydride generation atomic absorption spectrometry with microwave oven on-line prereduction of Se(VI) to Se(IV)

NASA Astrophysics Data System (ADS)

Burguera, J. L.; Carrero, P.; Burguera, M.; Rondon, C.; Brunetto, M. R.; Gallignani, M.

1996-12-01

An on-line flow injection system has been developed for the selective determination of Se(IV) and Se(VI) in citric fruit juices and geothermal waters by hydride generation atomic absorption spectrometry with microwave-aided heating prereduction of Se(VI) to Se(IV). The samples and the prereductant solutions (4 mol l -1 HCl for Se(IV) and 12 mol l -1 HCl for Se(VI)) which circulated in a closed-flow circuit were injected by means of a time-based injector. This mixture was displaced by a carrier solution of 1% v/v of hydrochloric acid through a PTFE coil located inside the focused microwave oven and mixed downstream with a borohydride solution to generate the hydride. The linear ranges were 0-120 and 0-100 μg l -1 of Se(IV) and Se(VI), respectively. The detection limits were 1.0 μg l -1 for Se(IV) and 1.5 μg l -1 for Se(VI). The precision (about 2.0-2.5% RSD) and recoveries (96-98% for Se(IV) and 94-98% for Se(VI)) were good. Total selenium values were also obtained by electrothermal atomic absorption spectrometry which agreed with the content of both selenium species. The sample throughput was about 50 measurements per hour. The main advantage of the method is that the selective determination of Se(IV) and Se(VI) in citric fruit juices and geothermal waters is performed in a closed system with a minimum sample manipulation, exposure to the environment, minimum sample waste and operator attention.

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

PubMed

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.

Bacterial Cr(VI) reduction concurrently improves sunflower (Helianthus Annuus L.) growth.

PubMed

Faisal, Muhammad; Hasnain, Shahida

2005-07-01

Four Cr(VI)-reducing bacterial strains (Ochrobactrum intermedium, CrT-2, CrT-3 and CrT-4) previously isolated from chromium-contaminated sites were inoculated on to seeds of sunflower (Helianthus annuus var SF-187), which were germinated and grown along with non-inoculated controls with chromate salts (300 microg CrCl3 or K2CrO4 ml(-1)). Severe reduction (20%) in seed germination was observed in Cr(VI) stress. Plant height decreased (36%) with Cr(VI) when compared with chromium-free control, while O. intermedium inoculation resulted a 20% increment in this parameter as compared to non-inoculated chromium-free control. CrT-3 inoculation resulted a 69% increment in auxin content as compared to non-inoculated control. O. intermedium caused 30% decrease in chromium uptake in sunflower plant roots under Cr(VI) stress as compared to chromium-free control plants.

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

PubMed

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.

Title VI: 1995-96 Final Report. Publication No. 95.11.

ERIC Educational Resources Information Center

Griffith, Julia E.

Title VI provide Federal funds to states through the Elementary and Secondary Education Act of 1965 as amended in 1994. Title VI funds can support one or more programs that include school reform activities, the purchase and use of instructional and educational materials, programs for the gifted and talented, and programs of various sorts for the…

Preparation and Cr(VI) removal performance of corncob activated carbon.

PubMed

Li, Hongyan; Gao, Pei; Cui, Jianguo; Zhang, Feng; Wang, Fang; Cheng, Jici

2018-05-12

Corncob activated carbon (CCAC) was prepared by a H 3 PO 4 activation method. The optimum conditions for the preparation of CCAC were determined by orthogonal experiments. The effects of pH, reaction time, CCAC dosage, and hexavalent chromium (Cr(VI)) concentrations on Cr(VI) removal by CCAC were studied. Corn straw activated carbon (CSAC) was also prepared using the optimum preparation conditions determined for CCAC. The properties of samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The results showed that the optimum preparation conditions for CCAC were as follows: a mass of corncob of 10 g; a mass ratio of corncob to H 3 PO 4 of 1:2; a 5% H 3 BO 3 content of 10 mL; an impregnation time of 45 min; a carbonization temperature of 500 °C. The optimum conditions for the removal of Cr(VI) were as follows: pH < 9; temperature, 308 K; rotation speed, 150 r min -1 ; reaction time, 60 min; CCAC dosage, 1 g L -1 . The Cr(VI) removal rate was above 98%, and the maximum adsorption capacity of CCAC was 9.985 mg g -1 . The concentration of residual Cr(VI) in water was less than 0.05 mg L -1 . FTIR showed that the surfaces of the samples had more oxygen-containing functional groups, which promoted the adsorption. XRD showed that CCAC and CSAC had similar peaks and that these peaks promoted the adsorption of Cr(VI). BET indicated that the number of pores in the samples followed the order CCAC > CSAC > CAC. SEM showed that the CCAC surface had a more porous structure, which enhanced adsorption. EDS showed that the C contents of CCAC and CSAC were much higher than that of CAC. Cr(VI) adsorption on CCAC followed quasi-second-order kinetics and was in accordance with a Langmuir adsorption isotherm, with monolayer adsorption. The adsorption reaction was endothermic, where higher

Papaya Seeds as A Low-Cost Sorbent for Removing Cr(VI) from The Aqueous Solution

NASA Astrophysics Data System (ADS)

Rahmawati, Atik; Marwoto, Putut; Karunia Z, Anita

2016-08-01

The presence of chromium (VI) contaminants and their toxicity in aqueous streams important environmental problems. Adsorption is one of the effective techniques that can be used for removing metal from wastewater. This research was initiated by preparing sorbent from papaya seeds and determining its functional group contents by using FT-IR. The adsorption process was carried out in a batch method. The study of adsorption aspects involved the pH, initial Cr (VI) concentration and contact time between Cr (VI) and sorbent. FT IR analysis results showed that the main functional groups are carbonyl, hydroxyl, and carboxylic. It was also found that the effective pH for Cr (VI) uptake is 2.0 and increasing contact time would increase the Cr (VI) uptake. In addition, the equilibrium was reached after 40 minutes interaction and the increase of initial chromium (VI) concentration would increase the sorbent uptake percentage. All these results indicated that papaya seed is a potential sorbent for removing Cr (VI) from aqueous solutions.

Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments

USGS Publications Warehouse

Yin, J.; Haggerty, R.; Stoliker, D.L.; Kent, D.B.; Istok, J.D.; Greskowiak, J.; Zachara, J.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. Copyright 2011 by the American Geophysical Union.

Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments

USGS Publications Warehouse

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.

Validation of the Preverbal Visual Assessment (PreViAs) questionnaire.

PubMed

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 (<2 years old) were divided into two groups according to 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.

Chromium (VI) biosorption by Saccharomyces cerevisiae subjected to chemical and thermal treatments.

PubMed

De Rossi, Andrea; Rigon, Magali Rejane; Zaparoli, Munise; Braido, Rafael Dalmas; Colla, Luciane Maria; Dotto, Guilherme Luiz; Piccin, Jeferson Steffanello

2018-05-28

The potential of chemically and thermally treated Saccharomyces cerevisiae as biosorbents for chromium (VI) was investigated in this work. The presence of this toxic metal in industrial effluents is harmful to the environment, so, it is important to develop environmental friendly methods for Cr(VI) removal from these effluents. Biosorption using microorganisms such as S. cerevisiae is a viable treatment option because this biomass is easily available as a residue of fermentation industries. In this study, the affecting variables on Cr(VI) biosorption were studied by constructing biosorption isotherms, using lyophilized yeast subjected to chemical and thermal treatments. S. cerevisiae was able to remove 99.66% of Cr(VI) from effluents by biosorption. The significant variables affecting biosorption were pH, initial Cr(VI) concentration, and contact time. The biosorption isotherms were represented by the Freundlich model for the untreated biomass, BET model for the chemically treated biomass, and Langmuir model for the heat-treated biomass. Thermal treatment increased the biosorption affinity of the biomass for chromium, while the chemical treatment facilitated the formation of a multilayer.

Influence of calcite and dissolved calcium on uranium(VI) sorption to a hanford subsurface sediment.

PubMed

Dong, Wenming; Ball, William P; Liu, Chongxuan; Wang, Zheming; Stone, Alan T; Bai, Jing; Zachara, John M

2005-10-15

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 thatformation 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.

Cathodic reduction of hexavalent chromium [Cr(VI)] coupled with electricity generation in microbial fuel cells.

PubMed

Wang, Gang; Huang, Liping; Zhang, Yifeng

2008-11-01

A novel approach to Cr(VI)-contaminated wastewater treatment was investigated using microbial fuel cell technologies in fed-batch mode. By using synthetic Cr(VI)-containing wastewater as catholyte and anaerobic microorganisms as anodic biocatalyst, Cr(VI) at 100 mg/l was completely removed during 150 h (initial pH 2). The maximum power density of 150 mW/m(2) (0.04 mA/cm(2)) and the maximum open circuit voltage of 0.91 V were generated with Cr(VI) at 200 mg/l as electron acceptor. This work verifies the possibility of simultaneous electricity production and cathodic Cr(VI) reduction.

Molecular characterization and phylogenetic analysis of Citrus viroid VI variants from citrus in China

USDA-ARS?s Scientific Manuscript database

Citrus viroid VI (CVd-VI) was originally found from citrus and persimmon in Japan. We report here the identification and molecular characterization of CVd-VI from four production regions of China. A total of 90 cDNA clones from nine infected citrus cultivars were sequenced. The sequence homologies o...

Method of manufacturing semiconductor having group II-group VI compounds doped with nitrogen

DOEpatents

Compaan, Alvin D.; Price, Kent J.; Ma, Xianda; Makhratchev, Konstantin

2005-02-08

A method of making a semiconductor comprises depositing a group II-group VI compound onto a substrate in the presence of nitrogen using sputtering to produce a nitrogen-doped semiconductor. This method can be used for making a photovoltaic cell using sputtering to apply a back contact layer of group II-group VI compound to a substrate in the presence of nitrogen, the back coating layer being doped with nitrogen. A semiconductor comprising a group II-group VI compound doped with nitrogen, and a photovoltaic cell comprising a substrate on which is deposited a layer of a group II-group VI compound doped with nitrogen, are also included.

Catalytic effect of soil colloids on the reaction between CrVI and p-methoxyphenol.

PubMed

Zhou, D M; Chen, H M; Zheng, C R; Tu, C

2001-01-01

Adsorption of CrVI and p-methoxyphenol (PMP) on soil colloids at different pH media was studied. The resulting k1 and n of 1.89 x 10(2) and 0.53 (r2 = 0.99) and k2 and b of 0.13 and 1.25 x 10(3) (r2 = 0.96) were obtained from Freundlich (Q = k1Caqn) and Langmuir [Q = k2bCaq/(1 + k2Caq)] simulation equations, respectively, for CrVI adsorption on soil colloids (pH 4.20). The adsorption of PMP on soil colloids in pH 5.72 media was simulated by five different equations and the results indicated that the Fritz-Schluender one (r2 = 1.00) was the most suitable among them. Adsorption quantity of CrVI and PMP on colloids increased with increasing acidity in the pH range of 3.5-9.0. Study of CrVI adsorption kinetics indicated that the adsorption equilibrium of CrVI was reached rapidly within 2 h. In pure aqueous solution, CrVI reduction by PMP was observed only when the media's pH was lower than 4.0. Oxidation and reduction reaction between CrVI and p-methoxyphenol obviously occurred when soil colloids were involved in this system, even at pH > or = 7.0, which strongly suggested that minerals in soil colloids acted as catalysts to speed the reaction of CrVI and PMP. The oxidized product of PMP by CrVI, extracted by chloroform in acid media and analyzed by gas chromatography-mass spectrometry, was identified as benzoquinone. The reaction included two steps of one electron process.

Assessment of calcium addition on the removal of U(VI) in the alkaline conditions created by NH 3 gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katsenovich, Yelena; Cardona, Claudia; Szecsody, Jim

Remediation of uranium (U) contamination in the deep vadose zone (VZ) sediments abundant in calcite mineral is a challenging task considering the formation of highly stable and mobile uranyl complexes with carbonate and calcium in pore water composition. There is a concern that uranium contamination in the VZ can serve as a continued source for groundwater pollution, creating a risk to human health and the environment through the groundwater pathway. This requires in-situ remediation of the radionuclide-contaminated VZ to convert soluble U species to low solubility precipitates that are stable in the natural environment. Injection of reactive gasses (e.g., NHmore » 3) is a promising technology to decrease U mobility in the unsaturated zone without the addition of liquid amendments. The NH 3 injection creates alkaline conditions that can alter the sediment pore water composition due to a release of elements from minerals (via desorption and dissolution) that are present in the sediment. However, it is not known how VZ pore water constituents (Si, Al 3+, HCO 3 -, and Ca 2 +) would affect U(VI) removal/precipitation in alkaline conditions. This study quantified the role of major pore water constituents typically present in the arid and semi-arid environments of the western regions of the U.S and identified solid uranium-bearing phases that could potentially precipitate from solutions approximating pore water compositions after pH manipulations via ammonia gas injections. Triplicate samples were prepared using six Si (5, 50 100, 150, 200, and 250 mM), six HCO 3 - (0, 3, 25, 50, 75, and 100 mM), and two Ca 2+ (5 and 10 mM) concentrations. The concentration of aluminum and uranium was kept constant at 5 mM and 0.0084 mM, respectively, in all synthetic formulations tested. Results showed that the percentage of U(VI) removal was controlled by the Si/Al molar ratios and Ca 2+ concentrations. Regardless of the bicarbonate concentration tested, the percentage of U(VI

Assessment of calcium addition on the removal of U(VI) in the alkaline conditions created by NH 3 gas

DOE PAGES

Katsenovich, Yelena; Cardona, Claudia; Szecsody, Jim; ...

2018-03-06

Remediation of uranium (U) contamination in the deep vadose zone (VZ) sediments abundant in calcite mineral is a challenging task considering the formation of highly stable and mobile uranyl complexes with carbonate and calcium in pore water composition. There is a concern that uranium contamination in the VZ can serve as a continued source for groundwater pollution, creating a risk to human health and the environment through the groundwater pathway. This requires in-situ remediation of the radionuclide-contaminated VZ to convert soluble U species to low solubility precipitates that are stable in the natural environment. Injection of reactive gasses (e.g., NHmore » 3) is a promising technology to decrease U mobility in the unsaturated zone without the addition of liquid amendments. The NH 3 injection creates alkaline conditions that can alter the sediment pore water composition due to a release of elements from minerals (via desorption and dissolution) that are present in the sediment. However, it is not known how VZ pore water constituents (Si, Al 3+, HCO 3 -, and Ca 2 +) would affect U(VI) removal/precipitation in alkaline conditions. This study quantified the role of major pore water constituents typically present in the arid and semi-arid environments of the western regions of the U.S and identified solid uranium-bearing phases that could potentially precipitate from solutions approximating pore water compositions after pH manipulations via ammonia gas injections. Triplicate samples were prepared using six Si (5, 50 100, 150, 200, and 250 mM), six HCO 3 - (0, 3, 25, 50, 75, and 100 mM), and two Ca 2+ (5 and 10 mM) concentrations. The concentration of aluminum and uranium was kept constant at 5 mM and 0.0084 mM, respectively, in all synthetic formulations tested. Results showed that the percentage of U(VI) removal was controlled by the Si/Al molar ratios and Ca 2+ concentrations. Regardless of the bicarbonate concentration tested, the percentage of U(VI

Genetics Home Reference: mucopolysaccharidosis type VI

MedlinePlus

... Citation on PubMed Garrido E, Cormand B, Hopwood JJ, Chabás A, Grinberg D, Vilageliu L. Maroteaux-Lamy ... N, Leão Teles E, Sá Miranda MC, Hopwood JJ. Mutational analysis of 105 mucopolysaccharidosis type VI patients. ...

Cr(VI) adsorption from electroplating plating wastewater by chemically modified coir pith.

PubMed

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

Study on Adsorption of Chromium (VI) by Activated Carbon from Cassava Sludge

NASA Astrophysics Data System (ADS)

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.

Efficacy trial of Vi polysaccharide vaccine against typhoid fever in south-western China.

PubMed Central

Yang, H. H.; Wu, C. G.; Xie, G. Z.; Gu, Q. W.; Wang, B. R.; Wang, L. Y.; Wang, H. F.; Ding, Z. S.; Yang, Y.; Tan, W. S.; Wang, W. Y.; Wang, X. C.; Qin, M.; Wang, J. H.; Tang, H. A.; Jiang, X. M.; Li, Y. H.; Wang, M. L.; Zhang, S. L.; Li, G. L.

2001-01-01

OBJECTIVE: To test the efficacy of locally produced Vi vaccine over a time period of longer than one year. METHODS: A double-blinded, randomized field trial was performed in Guangxi Zhuang Autonomous Region in south-western China, using 30 micrograms doses of locally produced Vi. Enrolled subjects were 3-50 years of age, although the majority (92%) were school-aged children, who have the highest rate of typhoid fever in this setting. A total of 131,271 people were systematically allocated a single dose of 30 micrograms of Vi polysaccharide or saline placebo. The study population was followed for 19 months, with passive surveillance conducted in the Ministry of Health and the Regional Health and Anti-epidemic Centre (HAEC). Clinically suspected cases of typhoid fever were confirmed by blood culture, or by serological reaction with O-antigen (Widal tests). FINDINGS: After 19 months, there were 23 culture-confirmed cases of typhoid fever in the placebo group versus 7 cases in the Vi group (Protective efficacy (PE) = 69%; 95% CI = 28%, 87%). Most of the isolates were from school-aged children: 22 cases in the placebo group versus 6 in the Vi group (PE = 72%; 95% CI = 32%, 82%). No serious post-injection reactions were observed. The locally produced Vi polysaccharide vaccine showed levels of protective efficacy similar to those for Vi vaccine produced in industrial countries. CONCLUSION: The slightly higher dose of vaccine did not seem to alter efficacy significantly in China. PMID:11477965

Determination of chromium (VI) in primary and secondary fertilizer and their respective precursors.

PubMed

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.

ViVaMBC: estimating viral sequence variation in complex populations from illumina deep-sequencing data using model-based clustering.

PubMed

Verbist, Bie; Clement, Lieven; Reumers, Joke; Thys, Kim; Vapirev, Alexander; Talloen, Willem; Wetzels, Yves; Meys, Joris; Aerssens, Jeroen; Bijnens, Luc; Thas, Olivier

2015-02-22

Deep-sequencing allows for an in-depth characterization of sequence variation in complex populations. However, technology associated errors may impede a powerful assessment of low-frequency mutations. Fortunately, base calls are complemented with quality scores which are derived from a quadruplet of intensities, one channel for each nucleotide type for Illumina sequencing. The highest intensity of the four channels determines the base that is called. Mismatch bases can often be corrected by the second best base, i.e. the base with the second highest intensity in the quadruplet. A virus variant model-based clustering method, ViVaMBC, is presented that explores quality scores and second best base calls for identifying and quantifying viral variants. ViVaMBC is optimized to call variants at the codon level (nucleotide triplets) which enables immediate biological interpretation of the variants with respect to their antiviral drug responses. Using mixtures of HCV plasmids we show that our method accurately estimates frequencies down to 0.5%. The estimates are unbiased when average coverages of 25,000 are reached. A comparison with the SNP-callers V-Phaser2, ShoRAH, and LoFreq shows that ViVaMBC has a superb sensitivity and specificity for variants with frequencies above 0.4%. Unlike the competitors, ViVaMBC reports a higher number of false-positive findings with frequencies below 0.4% which might partially originate from picking up artificial variants introduced by errors in the sample and library preparation step. ViVaMBC is the first method to call viral variants directly at the codon level. The strength of the approach lies in modeling the error probabilities based on the quality scores. Although the use of second best base calls appeared very promising in our data exploration phase, their utility was limited. They provided a slight increase in sensitivity, which however does not warrant the additional computational cost of running the offline base caller. Apparently

On the mechanism of Cr (VI)-induced carcinogenesis: dose dependence of uptake and cellular responses.

PubMed

Liu, K; Husler, J; Ye, J; Leonard, S S; Cutler, D; Chen, F; Wang, S; Zhang, Z; Ding, M; Wang, L; Shi, X

2001-06-01

Cr (VI) compounds are widely used industrial chemicals and are recognized human carcinogens. The mechanisms of carcinogenesis associated with these compounds remain to be investigated. The present study focused on dose-dependence of Cr (VI)-induced uptake and cellular responses. The results show that Cr (VI) is able to enter the cells (human lung epithelial cell line A549) at low concentration (< 10 microM) and that the Cr (VI) uptake appears to be a combination of saturable transport and passive diffusion. Electron spin resonance (ESR) trapping measurements showed that upon stimulation with Cr (VI), A549 cells were able to generate reactive oxygen species (ROS). The amount of ROS generated depended on the Cr (VI) concentration. ROS generation involved NADPH-dependent flavoenzymes. Cr (VI) affected the following cellular parameters in a dose-dependent manner, (a) activation of nuclear transcription factors NF-kappaB, and p53, (b) DNA damage, (c) induction of cell apoptosis, and (d) inhibition of cell proliferation. The activation of transcription factors was assessed by electrophoretic mobility shift assay and western blot analysis, DNA damage by single cell gel electrophoresis assay, cell apoptosis by DNA fragmentation assay, and cell proliferation by a non-radioactive ELISA kit. At the concentration range used in the present study, no thresholds were found in all of these cell responses to Cr (VI). The results may guide further research to better understand and evaluate the risk of Cr (VI)-induced carcinogenesis at low levels of exposure.

15 CFR Appendix Vi to Subpart P of... - Special-Use Areas Boundary Coordinates and Use Designations

Code of Federal Regulations, 2012 CFR

2012-01-01

... 15 Commerce and Foreign Trade 3 2012-01-01 2012-01-01 false Special-Use Areas Boundary Coordinates and Use Designations VI Appendix VI to Subpart P of Part 922 Commerce and Foreign Trade Regulations... Florida Keys National Marine Sanctuary Pt. 922, Subpt. P, App. VI Appendix VI to Subpart P of Part 922...

15 CFR Appendix Vi to Subpart P of... - Special-Use Areas Boundary Coordinates and Use Designations

Code of Federal Regulations, 2013 CFR

2013-01-01

... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Special-Use Areas Boundary Coordinates and Use Designations VI Appendix VI to Subpart P of Part 922 Commerce and Foreign Trade Regulations... Florida Keys National Marine Sanctuary Pt. 922, Subpt. P, App. VI Appendix VI to Subpart P of Part 922...

15 CFR Appendix Vi to Subpart P of... - Special-Use Areas Boundary Coordinates and Use Designations

Code of Federal Regulations, 2014 CFR

2014-01-01

... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Special-Use Areas Boundary Coordinates and Use Designations VI Appendix VI to Subpart P of Part 922 Commerce and Foreign Trade Regulations... Florida Keys National Marine Sanctuary Pt. 922, Subpt. P, App. VI Appendix VI to Subpart P of Part 922...

Phase I clinical trial of O-Acetylated pectin conjugate, a plant polysaccharide based typhoid vaccine

PubMed Central

Szu, Shousun C.; Lin, Kimi F-Y; Hunt, Steven; Chu, Chiayung; Thinh, Nguyen Duc

2014-01-01

Background Typhoid fever remains an important cause of morbidity and mortality in the developing countries. Vi capsular polysaccharide conjugate vaccine demonstrated safety and efficacy in young children in high endemic regions. A novel typhoid conjugate vaccine based on plant polysaccharide pectin was studied in a phase I trial. Methods Fruit pectin, having the same carbohydrate backbone structure as Vi, was purified from citrus peel and used as the polysaccharide source to prepare a semi-synthetic typhoid conjugate vaccine. Pectin was chemically O-acetylated (OAcPec) to antigenically resemble Vi and conjugated to carrier protein rEPA, a recombinant exoprotein A from Pseudomonas aeruginosa. 25 healthy volunteers, 18–45 years old, were injected once with OAcPec-rEPA. Safety and IgG antibodies reactive with Vi and pectin were analyzed. Results No vaccine associated serious adverse reaction was reported. Six weeks after the injection of OAcPec-rEPA, 64% of the volunteers elicited >4 fold rise of anti-Vi IgG. At 26 weeks the level declined, but the difference between the levels at 6 and 26 weeks are not statistically significant. There is a direct correlation between the level of anti-Vi IgG before and after the injection (R2 = 0.96). The anti-Vi IgG can be absorbed by Vi, but not by pectin. There was no corresponding increase of anti-pectin after the injection, indicating the antibody response to OAcPec-rEPA was specific to Vi. There is no Vi-rEPA data in US adults for comparison of immune responses. The OAcPec-rEPA elicited significantly less IgG anti-Vi in US adults than those by Vi-rEPA in Vietnamese adults. Conclusion The O-acetylated pectin conjugate, a plant based typhoid vaccine, is safe and immunogenic in adult volunteers. PMID:24657719

Race, space, place: notes on the racialisation and spatialisation of commercial sex work in Dubai, UAE.

PubMed

Mahdavi, Pardis

2010-11-01

This paper focuses on the perceived racialisation and resultant spatialisation of commercial sex in Dubai. In recent years, the sex industry in Dubai has grown to include women from the Middle East, Eastern Europe, East Asia and Africa. With the increase in sex workers of different nationalities has come a form of localised racism that is embedded in structures and desires seen within specific locations. The physical spatialisation of sex work hinges on perceived race and produces distinct income generating potential for women engaged in the sex industry in Dubai. The social and physical topography of Dubai is important in marginalising or privileging these various groups of sex workers, which correlates race, space and place with rights and assistance. I begin with a description of the multidirectional flows of causality between race, space, place and demand. I then discuss how these various groups are inversely spatialised within the discourse on assistance, protection and rights. The findings presented here are based on ethnographic research conducted with transnational migrants in the UAE in 2004, 2008 and 2009.

Reduction and removal of Cr(VI) from aqueous solutions using modified byproducts of beer production.

PubMed

Cui, Haojie; Fu, Minglai; Yu, Shen; Wang, Ming Kuang

2011-02-28

Biosorption, as an effective and low-cost technology treating industrial wastewaters containing Cr(VI), has become a significant concern worldwide. In this work, acid-modified byproducts of beer production (BBP) were used to remove Cr(VI) from aqueous solutions. Removal of Cr(VI) increases as the pH is decreased from 4.0 to 1.5, but the maximum of total Cr removal is obtained in a pH range from 2.0 to 2.5. Nearly 60% of the initial Cr(VI) (100 mg L(-1)) was adsorbed or reduced to Cr(III) within the first 10 min at pH 2.0. The Cr(VI) removal capability of acid-modified BBP materials was almost completely retained after regenerating with acid. FT-IR and XPS spectra revealed that carboxylate and carboxyl groups on the surface of modified BBP materials play a major role in Cr(VI) binding and reduction, whereas amide and other groups play a minor role in the Cr(VI) removal process. Copyright © 2010 Elsevier B.V. All rights reserved.

Adsorption isotherm studies of chromium (VI) from aqueous solutions using sol-gel hydrotalcite-like compounds.

PubMed

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.

Hydrothermal Carbonization of Microalgae (Chlorococcum sp.) for Porous Carbons With High Cr(VI) Adsorption Performance.

PubMed

Sun, Yuanyuan; Liu, Chang; Zan, Yifan; Miao, Gai; Wang, Hao; Kong, Lingzhao

2018-04-12

Porous carbon adsorbents were prepared from microalgae (Chlorococcum sp.) via directly hydrothermal carbonization coupled with KOH or NH 3 activation for Cr(VI) adsorption. KOH-activated porous carbons exhibit high Cr(VI) adsorption capacities than those obtained via NH 3 modification (370.37 > 95.70 mg/g). The superior Cr(VI) adsorption capacity is due to high surface areas (1784 m 2 /g) and pore volumes of porous carbon with mesoporous and macroporous structures. The Cr(VI) adsorption result was well fitted to the Langmuir model, showing that the removal of Cr(VI) was attributed to the monolayer adsorption of activity site on carbon surface.

A Green Microbial Fuel Cell-Based Biosensor for In Situ Chromium (VI) Measurement in Electroplating Wastewater.

PubMed

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.

A Green Microbial Fuel Cell-Based Biosensor for In Situ Chromium (VI) Measurement in Electroplating Wastewater

PubMed Central

Wu, Li-Chun; Tsai, Teh-Hua; Liu, Man-Hai; Kuo, Jui-Ling; Chang, Yung-Chu

2017-01-01

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 (r2 = 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. PMID:29076985

Reduction of Cr(VI) to Cr(III) by green rust - sulphate

NASA Astrophysics Data System (ADS)

Skovbjerg, L.; Stipp, S.

2003-04-01

Chromium is widely used in industrial processes such as leather tanning, electro-plating and as colour pigments. Unfortunately, hexavalent chromium is both toxic and very soluble so it can be a problem for groundwater resources. Given the right redox conditions, however, Cr(VI) can be reduced to trivalent chromium, which is much less soluble and is an essential trace nutrient. Fe(II), an element common in soil and sediments under anaerobic conditions, can serve as a reducing agent for Cr(VI). Green Rust (GR) is a layered Fe(II),Fe(III)-hydroxide with various anions compensating charge in the interlayers. It is very effective in reducing Cr(VI) to Cr(III). GR exists in nature and is thought to be precursor for the formation of Fe(III)-oxides and oxyhydroxides at the redox boundary. It may be that the formation of GR is a key process in the effectiveness of reactive barriers for groundwater remediation that are based on Fe(0). The purpose of this work is to investigate the mechanisms controlling Cr(VI) reduction by Green Rust, to examine the effect of Cr adsorption and incorporation on GR morphology and composition, and to define the role of parameters such as interlayer anion, initial Cr(VI) concentration and time. We are using freshly synthesised material that has not been dried to avoid structural changes that may accompany dehydration and rehydration. X-Ray Diffraction (XRD) is used to characterise mineral structural changes and Atomic Force Microscopy (AFM), to examine changes in morphology as reactions take place. By adjusting the concentration of Cr(VI), we can control the rate of surface change and we can observe the nanoscale particles directly.

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

PubMed Central

Magistrati, Elisa; Molteni, Erika; Lupia, Michela; Soffientini, Paolo; Rottner, Klemens; Cavallaro, Ugo; Pozzoli, Uberto; Mapelli, Marina; Walters, Kylie J.; Polo, Simona

2016-01-01

Myosin VI functions in endocytosis and cell motility. Alternative splicing of myosin VI mRNA generates two distinct isoform types, myosin VIshort and myosin VIlong, which differ in the C-terminal region. Their physiological and pathological role remains unknown. Here we identified an isoform-specific regulatory helix, named 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 novel clathrin-binding domain that is unique to myosin VIlong and masks the known RRL interaction motif. This finding is relevant to ovarian cancer, where alternative myosin VI splicing is aberrantly regulated, and exon skipping dictates cell addiction to myosin VIshort for tumor cell migration. The RRL interactor optineurin contributes to this process by selectively binding myosin VIshort. Thus the α2-linker acts like a molecular switch that assigns myosin VI to distinct endocytic (myosin VIlong) or migratory (myosin VIshort) functional roles. PMID:26950368

Removal of Cr(VI) from groundwater by Fe(0)

NASA Astrophysics Data System (ADS)

Gao, Yanjiao; Liu, Rui

2017-11-01

This research was conducted to investigate the treatment of hexavalent chromium (Cr(VI)) by iron powder (Fe(0)) columns of simulated permeable reactive barriers with and without calcium carbonate (CaCO3). Two columns filled with Fe(0) were used as Cr(VI) removal equipment running at a flow velocity of 10 ml/min at room temperature. After 200 days running of the two columns, the results showed that Fe(0) was an effective material for Cr(VI) reduction with an average removal rate of above 84.6%. The performance of Column 2 with CaCO3 was better than Column 1 without CaCO3 in terms of average Cr(VI) removal rate. The presence of CaCO3 buffered the increasing pH caused by Fe(0) corrosion in Column 2 and enhanced the removal rate of Column 2. Scanning Electron Microscopy (SEM) images of Fe(0) in the three stages of running of the two columns illustrated that the coat layer of Column 1 was a little thicker than that of Column 2. Energy-dispersive spectrometry (EDS) results showed that the surface of Fe(0) of Column 2 contained more chromium elements. Raman spectroscopy found that all iron oxide was generated on the Fe(0) surface of Column 1 and Column 2 and chromium class objects were only detected on Fe(0) surface in Column 2.

Spectroscopic characterization of iron-doped II-VI compounds for laser applications

NASA Astrophysics Data System (ADS)

Martinez, Alan

The middle Infrared (mid-IR) region of the electromagnetic spectrum between 2 and 15 ?m has many features which are of interest to a variety of fields such as molecular spectroscopy, biomedical applications, industrial process control, oil prospecting, free-space communication and defense-related applications. Because of this, there is a demand for broadly tunable, laser sources operating over this spectral region which can be easily and inexpensively produced. II-VI semiconductor materials doped with transition metals (TM) such as Co 2+, Cr2+, or Fe2+ exhibit highly favorable spectroscopic characteristics for mid-IR laser applications. Among these TM dopants, Fe2+ has absorption and emission which extend the farthest into the longer wavelength portion of the mid-IR. Fe2+:II-VI crystals have been utilized as gain elements in laser systems broadly tunable over the 3-5.5 microm range [1] and as saturable absorbers to Q -switch [2] and mode-lock [3] laser cavities operating over the 2.7-3 microm. TM:II-VI laser gain elements can be fabricated inexpensively by means of post-growth thermal diffusion with large homogeneous dopant concentration and good optical quality[4,5]. The work outlined in this dissertation will focus on the spectroscopic characterization of TM-doped II-VI semiconductors. This work can be categorized into three major thrusts: 1) the development of novel laser materials, 2) improving and extending applications of TM:II-VI crystals as saturable absorbers, and 3) fabrication of laser active bulk crystals. Because current laser sources based on TM:II-VI materials do not cover the entire mid-IR spectral region, it is necessary to explore novel laser sources to extend available emissions toward longer wavelengths. The first objective of this dissertation is the spectroscopic characterization of novel ternary host crystals doped with Fe2+ ions. Using crystal field engineering, laser materials can be prepared with emissions placed in spectral regions not

Study on the DNA-protein crosslinks induced by chromium (VI) in SPC-A1

NASA Astrophysics Data System (ADS)

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.

Field method for the determination of hexavalent chromium by ultrasonication and strong anion-exchange solid-phase extraction.

PubMed

Wang, J; Ashley, K; Marlow, D; England, E C; Carlton, G

1999-03-01

A simple, fast, sensitive, and economical field method was developed and evaluated for the determination of hexavalent chromium (CrVI) in environmental and workplace air samples. By means of ultrasonic extraction in combination with a strong anion-exchange solid-phase extraction (SAE-SPE) technique, the filtration, isolation, and determination of CrVI in the presence of trivalent chromium (CrIII) and potential interferents was achieved. The method entails (1) ultrasonication in basic ammonium buffer solution to extract CrVI from environmental matrixes; (2) SAE-SPE to separate CrVI from CrIII and interferences; (3) elution/acidification of the eluate; (4) complexation of chromium with 1,5-diphenylcarbazide; and (5) spectrophotometric determination of the colored chromium-diphenylcarbazone complex. Several critical parameters were optimized in order to effect the extraction of both soluble (K2CrO4) and insoluble (PbCrO4) forms of CrVI without inducing CrIII oxidation or CrVI reduction. The method allowed for the dissolution and purification of CrVI from environmental and workplace air sample matrixes for up to 24 samples simultaneously in less than 90 min (including ultrasonication). The results demonstrated that the method was simple, fast, quantitative, and sufficiently sensitive for the determination of occupational exposures of CrVI. The method is applicable for on-site monitoring of CrVI in environmental and industrial hygiene samples.

A modified model for calculating lattice thermal expansion of I{sub 2}-IV-VI{sub 3} and I{sub 3}-V-VI{sub 4} tetrahedral compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Omar, M.S.

2007-05-03

A general empirical formula was found for calculating lattice thermal expansion for compounds having their properties extended for compound groups having different mean ionicity as well as more than one type of cation atoms with that of different numbers of them such as I{sub 2}-IV-VI{sub 3} and I{sub 3}-V-VI{sub 4}. The difference in the valence electrons for cations and anions in the compound was used to correlate the deviations caused by the compound ionicity. The ionicity effects, which are due to their different numbers for their types, were also added to the correlation equation. In general, the lattice thermal expansionmore » for a compound semiconductor can be calculated from a relation containing melting point, mean atomic distance and number of valence electrons for the atoms forming the compound. The mean ionicity for the group compounds forming I{sub 2}-IV-VI{sub 3} was found to be 0.323 and 0.785 for the ternary group compounds of I{sub 3}-V-VI{sub 4}.« less

Removal of GaAs growth substrates from II-VI semiconductor heterostructures

NASA Astrophysics Data System (ADS)

Bieker, S.; Hartmann, P. R.; Kießling, T.; Rüth, M.; Schumacher, C.; Gould, C.; Ossau, W.; Molenkamp, L. W.

2014-04-01

We report on a process that enables the removal of II-VI semiconductor epilayers from their GaAs growth substrate and their subsequent transfer to arbitrary host environments. The technique combines mechanical lapping and layer selective chemical wet etching and is generally applicable to any II-VI layer stack. We demonstrate the non-invasiveness of the method by transferring an all-II-VI magnetic resonant tunneling diode. High resolution x-ray diffraction proves that the crystal integrity of the heterostructure is preserved. Transport characterization confirms that the functionality of the device is maintained and even improved, which is ascribed to completely elastic strain relaxation of the tunnel barrier layer.

AR4VI: AR as an Accessibility Tool for People with Visual Impairments.

PubMed

Coughlan, James M; Miele, Joshua

2017-10-01

Although AR technology has been largely dominated by visual media, a number of AR tools using both visual and auditory feedback have been developed specifically to assist people with low vision or blindness - an application domain that we term Augmented Reality for Visual Impairment (AR4VI). We describe two AR4VI tools developed at Smith-Kettlewell, as well as a number of pre-existing examples. We emphasize that AR4VI is a powerful tool with the potential to remove or significantly reduce a range of accessibility barriers. Rather than being restricted to use by people with visual impairments, AR4VI is a compelling universal design approach offering benefits for mainstream applications as well.

Spitznävi: unterschiedliche klinische, dermatoskopische und histopathologische Merkmale in der Kindheit.

PubMed

Dika, Emi; Neri, Iria; Fanti, Pier Alessandro; Barisani, Alessia; Ravaioli, Giulia Maria; Patrizi, Annalisa

2017-01-01

Die Charakterisierung der klinischen Merkmale und des biologischen Potenzials von Spitznävi hat in den letzten Jahrzehnten breites Interesse gefunden. Das Ziel dieser Arbeit ist die Beschreibung der klinischen und dermatoskopischen Merkmale von Spitznävi sowie des klinischen Ergebnisses nach chirurgischer Exzision von Spitznävi in drei pädiatrischen Altersgruppen. Restrospektive Studie zur Analyse von klinischen Merkmalen, videodermatoskopischen Bildern, histopathologischen Diagnosen und Behandlungsergebnissen. Der Grad der Pigmentierung wurde sowohl klinisch als auch histopathologisch beurteilt. Bei 71 Patienten wurden 72 spitzoide Neoplasien entfernt. Videodermatologische Bilder lagen für 41 Patienten vor. Das Muster der Pigmentierung korrelierte signifikant mit dem Alter der Patienten: Hyperpigmentierte Läsionen waren bei Vorschulkindern selten, bei Patienten von 7 bis 12 Jahren und ab 13 Jahren dagegen häufiger. Eine histopathologische Diagnose von atypischen Spitznävi wurde selten durchgeführt. Keiner der Patienten, bei denen ursprünglich ein atypischer Spitznävus diagnostiziert worden war, entwickelte ein Lokalrezidiv oder Metastasen während der anschließenden Nachbeobachtung. Pigmentierte Spitznävi traten im Alter ab 13 Jahren häufiger auf. Die Studie bestätigt andere Berichte über die Altersverteilung von Pigmentierungsmustern und hebt die geringe Anzahl atypischer Spitznävi bei pädiatrischen Patienten hervor sowie das Ausbleiben von Rezidiven bei der langfristigen Nachbeobachtung. © 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

Inhibition of bone resorption by Tanshinone VI isolated from Salvia miltiorrhiza Bunge.

PubMed

Nicolin, V; Dal Piaz, F; Nori, S L; Narducci, P; De Tommasi, N

2010-05-10

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.

PubMed

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.

Gas-Phase Coordination Complexes of UVIO{2/2+}, NpVIO{2/2+}, and PuVIO{2/2+} with Dimethylformamide

NASA Astrophysics Data System (ADS)

Rutkowski, Philip X.; Rios, Daniel; Gibson, John K.; van Stipdonk, Michael J.

2011-11-01

Electrospray ionization of actinyl perchlorate solutions in H2O with 5% by volume of dimethylformamide (DMF) produced the isolatable gas-phase complexes, [AnVIO2(DMF)3(H2O)]2+ and [AnVIO2(DMF)4]2+, where An = U, Np, and Pu. Collision-induced dissociation confirmed the composition of the dipositive coordination complexes, and produced doubly- and singly-charged fragment ions. The fragmentation products reveal differences in underlying chemistries of uranyl, neptunyl, and plutonyl, including the lower stability of Np(VI) and Pu(VI) compared with U(VI).

ViSC Social Competence Program

ERIC Educational Resources Information Center

Strohmeier, Dagmar; Hoffmann, Christine; Schiller, Eva-Maria; Stefanek, Elisabeth; Spiel, Christiane

2012-01-01

The ViSC Social Competence Program has been implemented in Austrian schools within the scope of a national strategy plan, Together Against Violence. The program is a primary preventive program designed for grades 5 to 8. The prevention of aggression and bullying is defined as a school development task, and the initial implementation of the program…

The VI-SENSE-vaginal discharge self-test to facilitate management of vaginal symptoms.

PubMed

Geva, Adam; Bornstein, Jacob; Dan, Michael; Shoham, Hadar Kessary; Sobel, Jack D

2006-11-01

This study was undertaken to evaluate a diagnostic panty liner (VI-SENSE) (Common Sense, Caesarea, Israel) developed to facilitate diagnosis of vaginal infections by detecting disordered acidity level. Five hundred sixteen women with vulvovaginal symptoms were enrolled. Final clinical diagnosis included Amsel criteria, Gram stain analysis, pH determination, and Trichomonas vaginalis and Candida culture. VI-SENSE strip color status estimated by patients was compared with clinical diagnosis and pH measurement by using nitrazine paper. Statistical analysis included sensitivity and specificity calculations. The VI-SENSE test was positive in 226 of 249 patients (90.8%) with bacterial vaginosis or trichomoniasis. Nitrazine pH paper revealed elevated pH in 165 (66.5%) and the amine test was positive in 160 (64.3%) patients. The VI-SENSE test was negative in 217 of 267 patients (81.3%) without trichomoniasis or bacterial vaginosis. The VI-SENSE was positive in 85 of 92 women (92%), with mixed vaginal infection including Candida and bacterial vaginosis or trichomoniasis. Amine test, nitrazine pH paper and physician diagnosis relying only on speculum examination were inferior and positive in only 65 (70%), 59 (64%), and 66 (72%) patients, respectively. The VI-SENSE test was found to be superior to traditional individual tests in facilitating preliminary diagnosis of vaginal infections.

Unconstrained steps of myosin VI appear longest among known molecular motors.

PubMed

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.

30 CFR 250.916 - What are the CVA's primary duties during the design phase?

Code of Federal Regulations, 2014 CFR

2014-07-01

... the design phase? (a) The CVA must use good engineering judgment and practices in conducting an...; (iv) Load determinations; (v) Stress analyses; (vi) Material designations; (vii) Soil and foundation...

30 CFR 250.916 - What are the CVA's primary duties during the design phase?

Code of Federal Regulations, 2012 CFR

2012-07-01

... the design phase? (a) The CVA must use good engineering judgment and practices in conducting an...; (iv) Load determinations; (v) Stress analyses; (vi) Material designations; (vii) Soil and foundation...

30 CFR 250.916 - What are the CVA's primary duties during the design phase?

Code of Federal Regulations, 2013 CFR

2013-07-01

... the design phase? (a) The CVA must use good engineering judgment and practices in conducting an...; (iv) Load determinations; (v) Stress analyses; (vi) Material designations; (vii) Soil and foundation...

ORFEUS spectroscopy of the O BT VI lines in symbiotic stars and the Raman scattering process

NASA Astrophysics Data System (ADS)

Schmid, H. M.; Krautter, J.; Appenzeller, I.; Barnstedt, J.; Dumm, T.; Fromm, A.; Gölz, M.; Grewing, M.; Gringel, W.; Haas, C.; Hopfensitz, W.; Kappelmann, N.; Krämer, G.; Lindenberger, A.; Mandel, H.; Mürset, U.; Schild, H.; Schmutz, W.; Widmann, H.

1999-08-01