Decolorization of Congo Red by Phanerochaete chrysosporium: the role of biosorption and biodegradation.

PubMed

Bosco, Francesca; Mollea, Chiara; Ruggeri, Bernardo

2017-10-01

The degradation of Congo Red by means of Phanerochaete chrysosporium BKM-F-1767 is reported in this work. Solid and liquid cultures have been prepared to evaluate in vivo biodegradation as well as the role of biosorption phenomena on mycelium. Moreover, in vitro tests have been performed to define the influence of MnP on dye decolorization. P. chrysosporium, cultivated on Malt Extract Agar in the presence of Congo Red 0.005% (w/v), has shown good growth and the ability to decolorize the dye in the 25-39°C temperature range. It has also been cultivated in a low NMM liquid medium with the aforementioned dye concentration in immobilized stationary cultures inducted for Lignin Peroxidase (LiP) and Manganese Peroxidase (MnP) production. Congo Red was absorbed on the biomass and then decolorized (93% and 85% for the LiP and MnP cultures, respectively). The cultures with added Congo Red have shown a higher MnP synthesis rate than a control without the dye. The enzymatic degradation of Congo Red has also been investigated by means of the extracellular fluid for different MnP activities (0-300 IU/l); the decolorization percentage has been found to be clearly related to the enzyme concentration up to a value of about 200 IU/l.

Lethal cardiac amyloidosis: Modification of the Congo Red technique on a forensic case.

PubMed

Rancati, A; Andreola, S; Bailo, P; Boracchi, M; Fociani, P; Gentile, G; Zoja, R

2018-05-26

Congo Red staining is usually used in diagnosing amyloidosis, a pathology characterized by the storage of abnormal proteins in several human organs. When assessed on samples fixated in formalin and embended in paraffin, this staining can undergo several artefacts, causing diagnostic and interpretative difficulties due to its weak stainability and a consequent reduced visibility of the amyloid. These complications, in time, requested several variations of this staining technique, especially in clinical practice, while in the forensic field no protocols has ever been adapted to cadaveric samples, a material that is already characteristically burdened by a peculiar stainability. In our work, studying a sudden death caused by cardiac amyloidosis and diagnosed only with post-mortem exams, we present a modified Congo Red staining used with the purpose to demonstrate amyloid in cadaveric material after the unsuccessfully use of all standard protocols. Copyright © 2018. Published by Elsevier B.V.

Evaluation of Aluminium Dross as Adsorbent for Removal of Carcinogenic Congo Red Dye in Wastewater

NASA Astrophysics Data System (ADS)

Zakaria, Mohamad Zulfika Hazielim b.; Zauzi, Nur Syuhada Ahmad; Baini, Rubiyah; Sutan, Norsuzailina Mohamed; Rezaur Rahman, Md

2017-06-01

In this study, aluminium dross waste generated from aluminium smelting industries was employed as adsorbent in removing of congo red dye in aqueous solution. The raw aluminium dross as adsorbent was characterized using Scanning Electron Microscope (SEM), Brunauer-Emmett-Teller (BET) for surface area and X-Ray Fluorescence (XRF) Spectroscopy. Adsorption experiments were carried out by batch system at different adsorbent mass, pH, and initial dye concentration. The results showed that the per cent removal of dye increased as adsorbent mass increased. It was found that 0.4 gram of adsorbent can remove approximately 100 % of dye at pH 9 for dye concentration 20 and 40 ppm. Therefore, it can be concluded that raw aluminium dross without undergone any treatment can be effectively used for the adsorption of congo red in textile wastewater related industries.

Force-field parametrization and molecular dynamics simulations of Congo red

NASA Astrophysics Data System (ADS)

Król, Marcin; Borowski, Tomasz; Roterman, Irena; Piekarska, Barbara; Stopa, Barbara; Rybarska, Joanna; Konieczny, Leszek

2004-01-01

Congo red, a diazo dye widely used in medical diagnosis, is known to form supramolecular systems in solution. Such a supramolecular system may interact with various proteins. In order to examine the nature of such complexes empirical force field parameters for the Congo red molecule were developed. The parametrization of bonding terms closely followed the methodology used in the development of the charmm22 force field, except for the calculation of charges. Point charges were calculated from a fit to a quantum mechanically derived electrostatic potential using the CHELP-BOW method. Obtained parameters were tested in a series of molecular dynamics simulations of both a single molecule and a micelle composed of Congo red molecules. It is shown that newly developed parameters define a stable minimum on the hypersurface of the potential energy and crystal and ab initio geometries and rotational barriers are well reproduced. Furthermore, rotations around C-N bonds are similar to torsional vibrations observed in crystals of diphenyl-diazene, which confirms that the flexibility of the molecule is correct. Comparison of results obtained from micelles molecular dynamics simulations with experimental data shows that the thermal dependence of micelle creation is well reproduced.

Accelerated decolorization of azo dye Congo red in a combined bioanode-biocathode bioelectrochemical system with modified electrodes deployment.

PubMed

Kong, Fanying; Wang, Aijie; Cheng, Haoyi; Liang, Bin

2014-01-01

In this study, BES with bioanode and biocathode was applied to decolorize an azo dye Congo red (CR). Results showed that the Congo red decolorization efficiency (CR-DE) within 23 h in a combined bioanode-biocathode single chamber BES was 98.3±1.3%, significantly higher than that of mixed solution in a dual chamber BES (67.2±3.5%) (P<0.005). Various electrodes deployments (horizontal, vertical and surrounding) in the combined bioanode-biocathode BES were further compared based on the decolorization performance and electrochemical characterization. Results indicated that CR-DE within 11h improved from 87.4±1.3% to 97.5±2.3%, meanwhile the internal resistance decreased from 236.6 to 42.2Ω as modifying the horizontal deployment to be a surrounding deployment. It proved that the combination of bioanode and biocathode with suitable electrodes deployment could accelerate the decolorization of azo dye Congo red, which would be great potential for the application of bioelectrochemical technology in azo dye wastewater treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

The effect of operational parameters on the photocatalytic degradation of Congo red organic dye using ZnO-CdS core-shell nano-structure coated on glass by Doctor Blade method.

PubMed

Habibi, Mohammad Hossein; Rahmati, Mohammad Hossein

2015-02-25

Photocatalytic degradation of Congo red was investigated using ZnO-CdS core-shell nano-structure coated on glass by Doctor Blade method in aqueous solution under irradiation. Field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques were used for the morphological and structural characterization of ZnO-CdS core-shell nanostructures. XRD results showed diffractions of wurtzite zinc oxide core and wurtzite cadmium sulfide shell. FESEM results showed that nanoparticles are nearly hexagonal with an average diameter of about 50 nm. The effect of catalyst loading, UV-light irradiation time and solution pH on photocatalytic degradation of Congo red was studied and optimized values were obtained. Results showed that the employment of efficient photocatalyst and selection of optimal operational parameters may lead to complete decolorization of dye solutions. It was found that ZnO-CdS core-shell nano-structure is more favorable for the degradation of Congo red compare to pure ZnO or pure CdS due to lower electron hole recombination. The results showed that the photocatalytic degradation rate of Congo red is enhanced with increasing the content of ZnO up to ZnO(0.2 M)/CdS(0.075 M) which is reached 88.0% within 100 min irradiation. Copyright © 2014 Elsevier B.V. All rights reserved.

Use of hydroxypropyl-β-cyclodextrin/polyethylene glycol 400, modified Fe3O4 nanoparticles for congo red removal.

PubMed

Yu, Lan; Xue, Weihua; Cui, Lei; Xing, Wen; Cao, Xinli; Li, Hongyu

2014-03-01

Fe3O4 nanoparticles were modified with Hydroxypropyl-β-cyclodextrin (HP-β-CD) and Polyethylene glycol 400 (PEG400) by a facile one-pot homogeneous precipitation method, and were used as a novel nano-adsorbent for the removal of congo red (CR) from aqueous solutions. The polymer-modified composites were characterized by FTIR, TEM, TGA, XRD and VSM, and showed excellent adsorption efficiency for CR. The value of the maximum adsorption capacity calculated according to the Langmuir isotherm model were 1.895g/g, which are much high and about 19 times that of Fe3O4 nanoparticles. Desorption study further indicates the good regeneration ability of the nanocomposites. The results suggest that the HP-β-CD/PEG400-modified Fe3O4 nanoparticles is a promising adsorbent for CR removal from aqueous solutions, and it is easily recycled owing to its large specific surface area and unique magnetic responsiveness. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Congo red agar, a differential medium for Aeromonas salmonicida, detects the presence of the cell surface protein array involved in virulence.

PubMed Central

Ishiguro, E E; Ainsworth, T; Trust, T J; Kay, W W

1985-01-01

Strains of the fish pathogen Aeromonas salmonicida which possess the cell surface protein array known as the A-layer (A+) involved in virulence formed deep red colonies on tryptic soy agar containing 30 micrograms of Congo red per ml. These were readily distinguished from colorless or light orange colonies of avirulent mutants lacking A-layer (A-). The utility of Congo red agar for quantifying A+ and A- cells in the routine assessment of culture virulence was demonstrated. Intact A+ cells adsorbed Congo red, whereas A- mutants did not bind Congo red unless first permeabilized with EDTA. The dye-binding component of A+ cells was shown to be the 50,000-Mr A-protein component of the surface array. Purified A-protein avidly bound Congo red at a dye-to-protein molar ratio of about 30 by a nonspecific hydrophobic mechanism enhanced by high salt concentrations. Neither A+ nor A- cells adsorbed to Congo red-Sepharose columns at low salt concentrations. On the other hand, A+ (but not A-) cells were avidly bound at high salt concentrations. Images PMID:3934141

Explore various co-substrates for simultaneous electricity generation and Congo red degradation in air-cathode single-chamber microbial fuel cell.

PubMed

Cao, Yunqing; Hu, Yongyou; Sun, Jian; Hou, Bin

2010-08-01

Microbial fuel cell (MFC) holds a great promise to harvest electricity directly from a wide range of ready degradable organic matters and enhance degradation of some recalcitrant contaminants. Glucose, acetate sodium and ethanol were separately examined as co-substrates for simultaneous bioelectricity generation and Congo red degradation in a proton exchange membrane (PEM) air-cathode single-chamber MFC. The batch test results showed that more than 98% decolorization at the dye concentration of 300 mg/L were achieved within 36 h for all tested co-substrates during electricity generation. The decolorization rate was different with the co-substrates used. The fastest decolorization rate was achieved with glucose followed by ethanol and sodium acetate. Accumulated intermediates were observed during Congo red degradation which was demonstrated by UV-Visible spectra and high performance liquid chromatography (HPLC). Electricity generation was sustained and not significantly affected by the Congo red degradation. Glucose, acetate sodium and ethanol produced maximum power densities of 103 mW/m(2), 85.9 mW/m(2) and 63.2 mW/m(2), respectively, and the maximum voltage output decreased by only 7% to 15%. Our results demonstrated the feasibility of using various co-substrates for simultaneous decolorization of Congo red and bioelectricity generation in the MFC and showed that glucose was the preferred co-substrate. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Why Congo red binding is specific for amyloid proteins - model studies and a computer analysis approach.

PubMed

Roterman, I; KrUl, M; Nowak, M; Konieczny, L; Rybarska, J; Stopa, B; Piekarska, B; Zemanek, G

2001-01-01

The complexing of Congo red in two different ligand forms - unimolecular and supramolecular (seven molecules in a micelle) - with eight deca-peptides organized in a b-sheet was tested by computational analysis to identify its dye-binding preferences. Polyphenylananine and polylysine peptides were selected to represent the specific side chain interactions expected to ensure particularly the stabilization of the dye-protein complex. Polyalanine was used to verify the participation of non-specific backbone-derived interactions. The initial complexes for calculation were constructed by intercalating the dye between the peptides in the middle of the beta-sheet. The long axis of the dye molecule (in the case of unimolecular systems) or the long axis of the ribbon-like micelle (in the case of the supramolecular dye form) was oriented parallel to the peptide backbone. This positioning maximally reduced the exposure of the hydrophobic diphenyl (central dye fragment) to water. In general the complexes of supramolecular Congo red ligands appeared more stable than those formed by individual dye molecules. Specific interactions (electrostatic and/or ring stacking) dominated as binding forces in the case of the single molecule, while non-specific surface adsorption seemed decisive in complexing with the supramolecular ligand. Both the unimolecular and supramolecular versions of the dye ligand were found to be likely to form complexes of sufficient stability with peptides. The low stability of the protein and the gap accessible to penetration in the peptide sheet seem sufficient for supramolecular ligand binding, but the presence of positively charged or hydrophobic amino acids may strengthen binding significantly. The need for specific interaction makes single-molecule Congo red binding rather unusual as a general amyloid protein ligand. The structural feature of Congo red, which enables specific and common interaction with amyloid proteins, probably derives from the ribbon

Photocatalytic removal of Congo red dye using MCM-48/Ni2O3 composite synthesized based on silica gel extracted from rice husk ash; fabrication and application.

PubMed

Shaban, Mohamed; Abukhadra, Mostafa R; Hamd, Ahmed; Amin, Ragab R; Abdel Khalek, Ahmed

2017-12-15

MCM-48 mesoporous silica was successfully synthesized from silica gel extracted from rice husk ash and loaded by nickel oxide (Ni 2 O 3 ). The resulted composite was characterized using X-ray diffraction, scanning electron microscope, and UV-vis spectrophotometer. The role of MCM-48 as catalyst support in enhancing the photocatalytic properties of nickel oxide was evaluated through the photocatalytic degradation of Congo red dye under visible light source. MCM-48 as catalyst support for Ni 2 O 3 shows considerable enhancement in the adsorption capacity by 17% and 29% higher than the adsorption capacity of MCM-48 and Ni 2 O 3 , respectively. Additionally, the photocatalytic degradation percentage increased by about 64% relative to the degradation percentage using Ni 2 O 3 as a single component. The adsorption mechanism of MCM-48/Ni 2 O 3 is chemisorption process of multilayer form. The using of MCM-48 as catalyst support for Ni 2 O 3 enhanced the adsorption capacity and the photocatalytic degradation through increasing the surface area and prevents the nickel oxide particles from agglomeration. This was done through fixing nickel oxide particles throughout the porous structure which providing more exposed active adsorption sites and active photocatalyst sites for the incident photons. Based on the obtained results, supporting of nickel oxide particles onto MCM-48 are promising active centers for the degradation of Congo red dye molecules. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biosorption of Congo Red from aqueous solution by Bacillus weihenstephanensis RI12; effect of SPB1 biosurfactant addition on biodecolorization potency.

PubMed

Mnif, Inès; Fendri, Raouia; Ghribi, Dhouha

2015-01-01

Bacillus weihenstephanensis RI12, isolated from hydrocarbon contaminated soil, was assessed for Congo Red bio-treatment potency. Results suggested the potential of this bacterium for use in effective treatment of Congo Red contaminated wastewaters under shaking conditions at acidic and neutral pH value. The strain could tolerate higher doses of dyes as it could decolorize up to 1,000 mg/l of Congo Red. When used as microbial surfactant to enhance Congo Red biodecolorization, Bacillus subtilis SPB1-derived lipopeptide accelerated the decolorization rate and maximized the decolorization efficiency at an optimal concentration of biosurfactant of about 0.075%. Studies ensured that Congo Red removal by this strain could be due to an adsorption phenomena. Germination potencies of tomato seeds using the treated dyes under different conditions showed the efficient biotreatment of the azo dye Congo Red especially with the addition of SPB1 biosurfactant. To conclude, the addition of SPB1 bioemulsifier reduced energy costs by reducing the effective decolorization period; the biosurfactant stimulated bacterial decolorization method may provide a highly efficient, inexpensive and time-saving procedure in the treatment of textile effluents.

Evaluation of the chitin-binding dye Congo red as a selection agent for the isolation, classification, and enumeration of ascomycete yeasts.

PubMed

Linder, Tomas

2018-05-01

Thirty-nine strains of ascomycete yeasts representing 35 species and 33 genera were tested for their ability to grow on solid agar medium containing increasing concentrations of the chitin-binding dye Congo red. Six strains were classified as hypersensitive (weak or no growth at 10 mg/l Congo red), five were moderately sensitive (weak or no growth at 50 mg/l), three were moderately tolerant (weak or no growth at 100 mg/l), while the remaining 25 strains were classified as resistant (robust growth at ≥ 100 mg/l) with 20 of these strains classified as hyper-resistant (robust growth at 200 mg/l). Congo red growth phenotypes were consistent within some families but not others. The frequency of Congo red resistance among ascomycete yeasts was deemed too high for the practical use of Congo red as a selection agent for targeted isolation, but can be useful for identification and enumeration of yeasts.

Influence of the amyloid dye Congo red on curli, cellulose, and the extracellular matrix in E. coli during growth and matrix purification.

PubMed

Reichhardt, Courtney; McCrate, Oscar A; Zhou, Xiaoxue; Lee, Jessica; Thongsomboon, Wiriya; Cegelski, Lynette

2016-11-01

Microbial biofilms are communities of cells characterized by a hallmark extracellular matrix (ECM) that confers functional attributes to the community, including enhanced cohesion, adherence to surfaces, and resistance to external stresses. Understanding the composition and properties of the biofilm ECM is crucial to understanding how it functions and protects cells. New methods to isolate and characterize ECM are emerging for different biofilm systems. Solid-state nuclear magnetic resonance was used to quantitatively track the isolation of the insoluble ECM from the uropathogenic Escherichia coli strain UTI89 and understand the role of Congo red in purification protocols. UTI89 assembles amyloid-integrated biofilms when grown on YESCA nutrient agar. The ECM contains curli amyloid fibers and a modified form of cellulose. Biofilms formed by UTI89 and other E. coli and Salmonella strains are often grown in the presence of Congo red to visually emphasize wrinkled agar morphologies and to score the production of ECM. Congo red is a hallmark amyloid-binding dye and binds to curli, yet also binds to cellulose. We found that growth in Congo red enabled more facile extraction of the ECM from UTI89 biofilms and facilitates isolation of cellulose from the curli mutant, UTI89ΔcsgA. Yet, Congo red has no influence on the isolation of curli from curli-producing cells that do not produce cellulose. Sodium dodecyl sulfate can remove Congo red from curli, but not from cellulose. Thus, Congo red binds strongly to cellulose and possibly weakens cellulose interactions with the cell surface, enabling more complete removal of the ECM. The use of Congo red as an extracellular matrix purification aid may be applied broadly to other organisms that assemble extracellular amyloid or cellulosic materials. Graphical abstract Solid-state NMR was used to quantitatively track the isolation of the insoluble amyloid-associated ECM from uropathogenic E. coli and understand the role of Congo red in

Degradation of Active Brilliant Red X-3B by a microwave discharge electrodeless lamp in the presence of activated carbon.

PubMed

Fu, Jie; Wen, Teng; Wang, Qing; Zhang, Xue-Wei; Zeng, Qing-Fu; An, Shu-Qing; Zhu, Hai-Liang

2010-06-01

Degradation of Active Brilliant Red X-3B (X-3B) in aqueous solution by a microwave discharge electrodeless lamp (MDEL) in the presence of activated carbon was investigated. The preliminary results proved this method could effectively degrade X-3B in aqueous solution. The removal percentages of colour and chemical oxygen demand were up to approximately 99% and 66%, respectively, at the conditions of 0.8 g/L dye concentration, 20 g/L activated carbon, pH 7.0 and 8 min microwave irradiation time. The degradation basically belonged to first-order reaction kinetics and its rate constant was 0.42 min(-1). No aromatic organics were detected in the final treated solution, indicating that the mineralization was relatively complete. By studying the change in solution properties, it could be concluded that MDEL-assisted oxidation was the dominant reaction mechanism. In addition, the influence of operational parameters and reuse of activated carbon were also discussed.

Understanding the degradation of Congo red and bacterial diversity in an air-cathode microbial fuel cell being evaluated for simultaneous azo dye removal from wastewater and bioelectricity generation.

PubMed

Sun, Jian; Li, Youming; Hu, Yongyou; Hou, Bin; Zhang, Yaping; Li, Sizhe

2013-04-01

We investigated the mechanism of Congo red degradation and bacterial diversity in a single-chambered microbial fuel cell (MFC) incorporating a microfiltration membrane and air-cathode. The MFC was operated continuously for more than 4 months using a mixture of Congo red and glucose as fuel. We demonstrated that the Congo red azo bonds were reduced at the anode to form aromatic amines. This is consistent with the known mechanism of anaerobic biodegradation of azo dyes. The MFC developed a less dense biofilm at the anode in the presence of Congo red compared to its absence indicating that Congo red degradation negatively affected biofilm formation. Denaturing gradient gel electrophoresis and direct 16S ribosomal DNA gene nucleotide sequencing revealed that the microbial communities differed depending on whether Congo red was present in the MFC. Geobacter-like species known to generate electricity were detected in the presence or absence of Congo red. In contrast, Azospirillum, Methylobacterium, Rhodobacter, Desulfovibrio, Trichococcus, and Bacteroides species were only detected in its presence. These species were most likely responsible for degrading Congo red.

Congo Red Stain Identifies Matrix Overproduction and Is an Indirect Measurement for c-di-GMP in Many Species of Bacteria.

PubMed

Jones, Christopher J; Wozniak, Daniel J

2017-01-01

Congo red is a diazo textile dye that has been used to visualize the production of amyloid fibers for nearly a century. Microbiological applications were later developed, especially in identifying strains that produce amyloid appendages called curli and overexpressing polysaccharides in the biofilm matrix. The second messenger cyclic diguanylate (c-di-GMP) regulates the production of biofilm matrix polysaccharides, and therefore Congo red staining of samples can be utilized as an indirect measurement of elevated c-di-GMP production in bacteria. Congo red allows the identification of strains producing high c-di-GMP in an inexpensive, quantitative, and high-throughput manner.

Synthesis of hierarchical Ni(OH)(2) and NiO nanosheets and their adsorption kinetics and isotherms to Congo red in water.

PubMed

Cheng, Bei; Le, Yao; Cai, Weiquan; Yu, Jiaguo

2011-01-30

Ni(OH)(2) and NiO nanosheets with hierarchical porous structures were synthesized by a simple chemical precipitation method using nickel chloride as precursors and urea as precipitating agent. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy and nitrogen adsorption-desorption isotherms. Adsorption of Congo red (CR) onto the as-prepared samples from aqueous solutions was investigated and discussed. The pore structure analyses indicate that Ni(OH)(2) and NiO nanosheets are composed of at least three levels of hierarchical porous organization: small mesopores (ca. 3-5 nm), large mesopores (ca. 10-50 nm) and macropores (100-500 nm). The equilibrium adsorption data of CR on the as-prepared samples were analyzed by Langmuir and Freundlich models, suggesting that the Langmuir model provides the better correlation of the experimental data. The adsorption capacities for removal of CR was determined using the Langmuir equation and found to be 82.9, 151.7 and 39.7 mg/g for Ni(OH)(2) nanosheets, NiO nanosheets and NiO nanoparticles, respectively. Adsorption data were modeled using the pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetics equations. The results indicate that pseudo-second-order kinetic equation and intra-particle diffusion model can better describe the adsorption kinetics. The as-prepared Ni(OH)(2) and NiO nanosheets are found to be effective adsorbents for the removal of Congo red pollutant from wastewater as a result of their unique hierarchical porous structures and high specific surface areas. Copyright © 2010 Elsevier B.V. All rights reserved.

Synthesis of Magnesium Ferrites for the Adsorption of Congo Red from Aqueous Solution Using Batch Studies

NASA Astrophysics Data System (ADS)

Erdawati, E.; Darsef, D.

2018-04-01

A sol gel method with citric acid as an anionic surfactant was used to fabricate nano magnesium ferrites (MgFe2O4) under different calcination temperatures for 2h, respectively. The microstructure and surface morphology of magnesium ferrite powder were characterized by FTIR, XRD, SEM, and BET. The results of this study are useful for adsorption Congo red. The results showed that increasing solution pH and extending contact time are favorable for improving adsorption efficiency. with initial Congo red concentration of 50 mg/L and 100 mg/L. Adsorption data fits well with the Langmuir isotherm models with a maximum adsorption capacity (qm) and a Langmuir adsorption equilibrium constant (K) of 65.1 mg/g and 0.090 L/mg, respectively. The adsorption kinetic agrees well with pseudo second order model with the pseudo second rate constants (K2) of 0.0468 and0.00189 g/mg/min for solutions with initial congo red of 50 and 100 mg/L, respectively

Discrepancies between descriptions and illustrations of colours in Congo red-stained amyloid, and explanation of discrepant colours.

PubMed

Howie, Alexander J; Owen-Casey, Mared P

2010-09-01

Congo red-stained sections of amyloid may show various colours between crossed polariser and analyser. The aims were to see how papers described the colours, to compare descriptions with illustrations, and to explain the colours. In 160 papers on Congo red-stained amyloid, the commonest descriptions were 'green birefringence' and 'apple-green birefringence'. In 191 figures in 82 papers, 59 (31%) showed a pure green colour, 62 (32%) showed green and yellow or blue and yellow, 38 (20%) showed green and a colour other than yellow, mostly red, and 32 (17%) showed other colours. Discrepancies between colours reported and illustrated were noted in 127 figures (66%). Most (77) were between green alone in descriptions and green and another colour in figures, and 30 were between green in descriptions and no green at all in figures. Pure green can be seen in ideal conditions, but more often there are green and yellow, explained by strain birefringence, and green and red or other combinations, explained by uncrossing of polariser and analyser. These other anomalous colours are just as characteristic of amyloid as the pure green colour. Many papers on Congo red-stained amyloid appear to describe what is expected theoretically rather than what is actually seen.

Ultrasound-promoted coating of MOF-5 on silk fiber and study of adsorptive removal and recovery of hazardous anionic dye "congo red".

PubMed

Khanjani, Somayeh; Morsali, Ali

2014-07-01

A metal-organic framework MOF-5 has been synthesized on silk fiber through electrostatic layer-by-layer assembly. The silk surface coating was formed via sequential dipping in an alternating bath of metal and ligand solutions at room temperature by direct mixing. SEM was used to investigate the growth of MOF-5 coating as materials for separation membrane due to their desirable properties in adsorptive removal of congo red (CR) from contaminated water. The adsorption capacity of MOF-5 is remarkable high in the liquid phase. The adsorption of CR at various concentration and contact time in spontaneous process were studied. The silk fibers containing MOF-5 open a wide field of possible applications, such as protection layers or membranes in pollution remediation wastewater and any effluent. Desorption of the dye can be carried out by using NaOH solution with more than about 50% recovery of congo red from MOF-5 coated on silk membrane filtration. In order to investigate the role of sonicating on the morphology of products, one of the reactions was performed with ultrasound irradiation and the crystal growth is completed more than other methods. The samples and adsorption of CR were characterized with SEM, powder X-ray diffraction (XRD) and UV-visible spectroscopy. Copyright © 2014 Elsevier B.V. All rights reserved.

Adsorptive removal of Congo red from aqueous solutions using crosslinked chitosan and crosslinked chitosan immobilized bentonite.

PubMed

Huang, Ruihua; Zhang, Lujie; Hu, Pan; Wang, Jing

2016-05-01

Batch experiments were executed to investigate the removal of Congo red (CR) from aqueous solutions using the crosslinked chitosan (CCS) and crosslinked chitosan immobilized bentonite (CCS/BT composite). The CCS and CCS/BT composite were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. The removal of CR was examined as a function of pH value of CR solution, contact time, and inorganic sodium salt and ionic strength. The equilibrium data of CCS and CCS/BT composite agreed well with the Langmuir model. The adsorption capacities of CCS and CCS/BT composite at 298K and natural pH value were 405 and 500 mg/g, respectively. The kinetic data correlated well with the pseudo-second-order model. The adsorption of CR onto the CCS was mainly controlled by chemisorption while the adsorption of CR onto the CCS/BT composite was controlled by chemisorption and the electrostatic attraction. Copyright © 2016 Elsevier B.V. All rights reserved.

[Synthesis and Study on Adsorption Property of Congo Red Molecularly Imprinted Polymer Nanospheres].

PubMed

Chang, Zi-qiang; Chen, Fu-bin; Zhang, Yu; Shi, Zuo-long; Yang, Chun-yan; Zhang, Zhu-jun

2015-07-01

Molecularly imprinted polymer nanospheres (MIP) were prepared with Congo red as the template, methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross linker, azodiisobutyronitrile (AIBN) as an initiator, and acetonitrile as the porogen by precipitation polymerization. The morphology of MIP was characterized by SEM and TEM which showed that the diameter of MIP was nanometer grade (90 nm) and the shape was homogeneous. The specific surface area and pore volumes of MIP and NIP were examined through Brunauer-Emett-Teller method of nitrogen adsorption experiments. Then, the adsorption and selective recognition ability of MIPs were evaluated using the equilibrium rebinding experiments. The results indicated that the prepared MIP showed a good selectivity recognition ability to its template. It concluded that MIP could be employed as an effective material for removing Congo red from waste water.

Peptidic β-sheet binding with Congo Red allows both reduction of error variance and signal amplification for immunoassays.

PubMed

Wang, Yunyun; Liu, Ye; Deng, Xinli; Cong, Yulong; Jiang, Xingyu

2016-12-15

Although conventional enzyme-linked immunosorbent assays (ELISA) and related assays have been widely applied for the diagnosis of diseases, many of them suffer from large error variance for monitoring the concentration of targets over time, and insufficient limit of detection (LOD) for assaying dilute targets. We herein report a readout mode of ELISA based on the binding between peptidic β-sheet structure and Congo Red. The formation of peptidic β-sheet structure is triggered by alkaline phosphatase (ALP). For the detection of P-Selectin which is a crucial indicator for evaluating thrombus diseases in clinic, the 'β-sheet and Congo Red' mode significantly decreases both the error variance and the LOD (from 9.7ng/ml to 1.1 ng/ml) of detection, compared with commercial ELISA (an existing gold-standard method for detecting P-Selectin in clinic). Considering the wide range of ALP-based antibodies for immunoassays, such novel method could be applicable to the analysis of many types of targets. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication of core-shell structured magnetic nanocellulose base polymeric ionic liquid for effective biosorption of Congo red dye.

PubMed

Beyki, Mostafa Hossein; Bayat, Mehrnoosh; Shemirani, Farzaneh

2016-10-01

Ionic liquids are considered to be a class of environmentally friendly compounds as combination of them with bioresource polymeric substances such as; cellulose, constitute emerging coating materials. Biosorption by polymeric ionic liquids exhibits an attractive green way that involves low cost and irrespective of toxicity. As a result, a novel polymeric ionic liquid has been developed by the reaction of one step synthesized Fe3O4-cellulose nanohybrid, epichlorohydrin and 1-methylimidazole and employed as a green sorbent for efficient biosorption of Congo red dye. Effective parameters on dye removing as well as their interactions were determined with response surface methodology (RSM). Congo red adsorption showed fast equilibrium time (11min) with maximum uptake of 131mgg(-1). Isotherm study revealed that Langmuir adsorption model can better describe dye adsorption behavior. Regeneration of the sorbent was performed with a mixture of methanol-acetone-NaOH (3.0molL(-1)) solution. Copyright © 2016 Elsevier Ltd. All rights reserved.

The increased flexibility of CDR loops generated in antibodies by Congo red complexation favors antigen binding.

PubMed

Krol, Marcin; Roterman, Irena; Drozd, Anna; Konieczny, Leszek; Piekarska, Barbara; Rybarska, Janina; Spolnik, Paweł; Stopa, Barbara

2006-02-01

The dye Congo red and related self-assembling compounds were found to stabilize immune complexes by binding to antibodies currently engaged in complexation to antigen. In our simulations, it was shown that the site that becomes accessible for binding the supramolecular dye ligand is located in the V domain, and is normally occupied by the N-terminal polypeptide chain fragment. The binding of the ligand disrupts the beta-structure in the domain, increasing the plasticity of the antigen-binding site. The higher fluctuation of CDR-bearing loops enhances antigen binding, and allows even low-affinity antibodies to be engaged in immune complexes. Experimental observations of the enhancement effect were supported by theoretical studies using L lambda chain (4BJL-PDB identification) and the L chain from the complex of IgM-rheumatoid factor bound to the CH3 domain of the Fc fragment (1ADQ-PDB identification) as the initial structures for theoretical studies of dye-induced changes. Commercial IgM-type rheumatoid factor (human) and sheep red blood cells with coupled IgG (human) were used for experimental tests aimed to reveal the dye-enhancement effect in this system. The specificity of antigen-antibody interaction enhanced by dye binding was studied using rabbit anti-sheep red cell antibodies to agglutinate red cells of different species. Red blood cells of hoofed mammals (horse, goat) showed weak enhancement of agglutination in the presence of Congo red. Neither agglutination nor enhancement were observed in the case of human red cells. The dye-enhancement capability in the SRBC-antiSRBC system was lost after pepsin-digestion of antibodies producing (Fab)2 fragments still agglutinating red cells. Monoclonal (myeloma) IgG, L lambda chain and ovoalbumin failed to agglutinate red cells, as expected, and showed no enhancement effect. This indicates that the enhancement effect is specific.

The role of the heat shock protein Hsp12p in the dynamic response of Saccharomyces cerevisiae to the addition of Congo red.

PubMed

Shamrock, Vanessa J; Duval, Jérôme F L; Lindsey, George G; Gaboriaud, Fabien

2009-05-01

In this study, we investigate the electrohydrodynamic and nanomechanical characteristics of two Saccharomyces cerevisiae yeast strains, a wild-type (WT) strain and a strain overexpressing (OE) Hsp12p, in the presence and absence of hydrophobic Congo red compound. By combining these two advanced biophysical methods, we demonstrate that Hsp12p proteins are mostly located within a thin layer (c. 10 nm thick) positioned at the external side of the cell wall. However, this Hsp12p-enriched layer does not prevent Congo red from entering the cell wall and from interacting with the chitin therein. The entrance of Congo red within the cell wall is reflected in an increase of the turgor pressure for the OE strain and a decrease of that for the WT strain. It is shown that these opposite trends are consistent with significant modulations of the water content within the cell wall from/to the cytoplasm. These are the result of changes in the hydrophobicity/hydrophilicity balance, as governed by the intertwined local concentration variations of Congo red and Hsp12p across the cell wall. In particular, the decrease of the turgor pressure in the case of WT strain upon addition of Congo red is shown to be consistent with an upregulation of Hsp12p in the close vicinity of the plasma membrane.

Certification procedures for sirius red F3B (CI 35780, Direct red 80).

PubMed

Dapson, R W; Fagan, C; Kiernan, J A; Wickersham, T W

2011-06-01

Sirius red F3B (CI 35780, Direct red 80) is a polyazo dye used principally in staining methods for collagen and amyloid. For certification by the Biological Stain Commission, a sample of the dye must exhibit an absorption spectrum of characteristic shape with a maximum at 528-529 nm, a small shoulder near 500 nm and narrow peaks at 372, 281-282 and 230-235 nm. Spot tests (color changes with addition of concentrated H(2)SO(4) or HCl and subsequent dilution or neutralization) also are applied. The dye must perform satisfactorily in the picro-sirius red method for collagen by providing red staining of all types of collagen with yellow and green birefringence of fibers. Llewellyn's alkaline sirius red method applied to tissue known to contain amyloid must show red coloration of the products with green birefringence. Dye content, which does not influence significantly the staining properties of sirius red F3B, is not assayed.

Sonocatalytic rapid degradation of Congo red dye from aqueous solution using magnetic Fe0/polyaniline nanofibers.

PubMed

Das, Raghunath; Bhaumik, Madhumita; Giri, Somnath; Maity, Arjun

2017-07-01

Nano-sized magnetic Fe 0 /polyaniline (Fe 0 /PANI) nanofibers were used as an effective material for sonocatalytic degradation of organic anionic Congo red (CR) dye. Fe 0 /PANI , was synthesized via reductive deposition of nano-Fe 0 onto the PANI nanofibers at room temperature. Prepared catalyst was characterized using HR-TEM, FE-SEM, XRD, FTIR instruments. The efficacy of catalyst in removing CR was assessed colorimetrically using UV-visible spectroscopy under different experimental conditions such as % of Fe 0 loading into the composite material, solution pH, initial concentration of dye, catalyst dosage, temperature and ultrasonic power. The optimum conditions for sonocatalytic degradation of CR were obtained at catalyst concentrations=500mg.L -1 , concentration of CR=200ppm, solution pH=neutral (7.0), temperature=30°C, % of Fe 0 loading=30% and 500W ultrasonic power. The experimental results showed that ultrasonic process could remove 98% of Congo red within 30min with higher Q max value (Q max =446.4 at 25°C). The rate of degradation of CR dye was much faster in this ultrasonic technique rather than conventional adsorption process. The degradation efficiency declined with the addition of common inorganic salts (NaCl, Na 2 CO 3 , Na 2 SO 4 and Na 3 PO 4 ). The rate of degradation suppressed more with increasing salt concentration. Kinetic and isotherm studies indicated that the degradation of CR provides pseudo-second order rate kinetic and Langmuir isotherm model compared to all other models tested. The excellent high degradation capacity of Fe 0 /PANI under ultrasonic irradiation can be explained on the basis of the formation of active hydroxyl radicals (OH) and subsequently a series of free radical reactions. Copyright © 2017 Elsevier B.V. All rights reserved.

Efficient and rapid degradation of Congo red dye with TiO2 based nano-photocatalysts

NASA Astrophysics Data System (ADS)

Narayan, Himanshu; Alemu, Hailemichael

2017-04-01

Degradation of Congo red (CR) dye with TiO2 based nano-photocatalyst (NPC) loaded with Nd3+ and Er3+ ions is reported. The chemical route of synthesis through co-precipitation/hydrolysis (CPH) was employed to produce NPCs with general composition TiO2[R2O3]x, {x = 0.1, 0.2; R □ Nd, Er} and particle size within 12 - 16 nm. Photocatalytic degradation under visible light was measured in terms of the percent degradation of CR in 180 min ({C}180\\prime), time taken to degrade to half of the initial CR concentration (t1/2) and apparent rate constant (kobs). For both doping types, values of {C}180\\prime close to 100% were obtained with x = 0.2 NPCs, indicating complete removal of the dye. For the same NPCs, very high values of kobs were found; 2.91 × 10-2 min-1 and 2.36 × 10-2 min-1, for Nd3+ and Er3+ loaded NPCs, respectively, suggesting very rapid degradation. Other NPCs with x = 0.1, also showed reasonably good and fast degradation of CR. The observations may be attributed to the small particle size of the NPCs. Moreover, from the DRS results it is observed that the addition of Nd3+ and Er3+ ions apparently introduces intermediate energy levels within the band gap of TiO2. Such new levels seem to support photocatalysis because they act as electron traps leading to effective suppression of the undesired e-/h+ recombination. To some meaningful extent they also facilitate the absorption of visible irradiations required in the process.

Removal of Congo red dye molecules by MnO2 nanorods.

PubMed

Yin, Bosi; Zhang, Siwen; Jiao, Yang; Liu, Yang; Qu, Fengyu; Ma, Yajie; Wu, Xiang

2014-09-01

Uniform MnO2 nanorods were synthesized successfully via a facile and effective hydrothermal approach. Scanning electron microscope images showed that the average diameter of the as-synthesized nanorod is about 30 nm and the length of that is about 5 μm, respectively. Photocatalytic experimental results indicate that Congo red can be degraded nearly completely (over 97%) after visible light irradiation of 120 min, demonstrating potential applications of such nanorod structures for wastewater purification.

Graphene oxide/ferroferric oxide/polyethylenimine nanocomposites for Congo red adsorption from water.

PubMed

Wang, Lina; Mao, Changming; Sui, Ning; Liu, Manhong; Yu, William W

2017-04-01

Graphene oxide/ferroferric oxide/polyethylenimine (GO/Fe 3 O 4 /PEI) nanocomposites were synthesized by an in situ growth of Fe 3 O 4 nanoparticles on GO sheets, and then modified by PEI. The GO/Fe 3 O 4 /PEI nanocomposites showed extremely high removal efficiency for anionic dye Congo Red (CR) due to the positively charged PEI molecules (methylene blue was also tested but with low adsorption capacity due to its cationic property). The CR removal capacity was 574.7 mg g -1 , higher than most of reported results. The adsorption kinetics could be well described by a pseudo-second-order model. Furthermore, GO/Fe 3 O 4 /PEI nanocomposites could be easily recycled by magnetic separation. The removal efficiency remained above 70% after five cycles.

Adsorption of Congo red dye onto antimicrobial terephthaloyl thiourea cross-linked chitosan hydrogels.

PubMed

El-Harby, Nouf F; Ibrahim, Shaimaa M A; Mohamed, Nadia A

2017-11-01

Adsorption capacity of three antimicrobial terephthaloyl thiourea cross-linked chitosan hydrogels for Congo red dye removal from its aqueous solution has been investigated for the first time in this work. These hydrogels were prepared by reacting chitosan with various amounts of terephthaloyl diisothiocyanate cross-linker. The effect of the hydrogel structural variations and several dye adsorption processing parameters to achieve the best adsorption capacity were investigated. The hydrogels' structural variations were obtained by varying their terephthaloyl thiourea moieties content. The processing variables included initial concentration of the dye solution, temperature and time of exposure to the dye. The adsorption kinetics and isotherms showed that the sorption processes were better fitted by the pseudo-second-order equation and the Langmuir equation, respectively. On the basis of the Langmuir analysis Congo red dye gave the maximum sorption capacity of 44.248 mg/g. The results obtained confirmed that the sorption phenomena are most likely to be controlled by chemisorption process. The adsorption reaction was endothermic and spontaneous according to the calculated results of adsorption thermodynamics.

Preparation and Characterization of Electro-Spun Fabricated Ag-TiO2 Composite Nanofibers and Its Enhanced Photo-Catalytic Activity for the Degradation of Congo Red.

PubMed

Jadhav, Arvind H; Zhang, Hongliang; Agyemang, Frank O; Hiremath, Vishwanath; Lee, Kyuyoung; Chandradass, Jeyaseelan; Seo, Jeong Gil; Kim, Hern

2015-10-01

Electro-spun fabricated TiO2 nanofibers were prepared by simple electro-spinning method, in subsequent step silver (Ag) was deposited using precipitation method and obtained Ag-TiO2 composite nanofibers. The properties and morphology of these prepared composite nanofibers were characterized by XRD, SEM, EDX, and TGA. The prepared electro-spun composite nanofibers were applied as catalyst for the photodegradation of Congo-red under immited solar light in aqueous solution. Result reveals that, Ag loaded TiO2 composite nanofibers were effectively increased photodegradation of Congo red compared with pure TiO2 nanofibers in analogous condition. As a result, 92.0% decomposition of Congo red was obtained by using 5 wt% of Ag loaded TiO2 composite nanofibers at room temperature in short reaction time using 300 W of solar light. In addition, photodegradation of Congo red was also studied under different experimental conditions such as amount of Ag loaded in TiO2 nanofibers and contact time. Moreover, we also studied sintering effect on TiO2 nanofibers and their consequent effect on photodegradation reaction. After completion of reaction, the nanofibers can be easily separated by filtration process and reused several times without significant loss of activity. Overall study reveals that, Ag-TiO2 composite nanofibers were strongly enhanced the surface activity for the photo catalytic degradation of Congo red under ambient condition.

Photoluminescence Properties of Red-Emitting Ca3Sr3-x(PO4)4:xEu3+ Phosphors for White Light-Emitting Diodes.

PubMed

Hakeem, D A; Park, K

2015-07-01

The photoluminescent properties of the Eu(3+)-activated Ca3Sr3(PO4)4 phosphors prepared by a solution combustion method were investigated. The excitation spectra of Ca3Sr3-x(PO4)4:xEu3+ (0.05 ≤ x ≤ 0.6) phosphors under 614 nm wavelength showed a broad band centered at 266 nm along with other peaks at 320, 362, 381, 394, 414, 464, and 534 nm. The emission spectra observed in the range of 450 to 750 nm under excitation at 394 nm were ascribed to the 5D0-7F1-4 transitions of Eu3+ ions. The Ca3Sr3-x(PO4)4:xEu3+ phosphors showed the strongest red emission at 614 nm due to the electric dipole 5DO -->7F2 transition of Eu3+. The strongest emission intensity was obtained for the Eu3+ ions of x = 0.5. The prepared Ca3Sr3-x(PO4)4:xEu3+ can be used as an efficient red phosphor for UV-based white LEDs.

Removal of Congo Red from Aqueous Solution by Anion Exchange Membrane (EBTAC): Adsorption Kinetics and Themodynamics.

PubMed

Khan, Muhammad Imran; Akhtar, Shahbaz; Zafar, Shagufta; Shaheen, Aqeela; Khan, Muhammad Ali; Luque, Rafael; Rehman, Aziz Ur

2015-07-08

The adsorption behavior of anionic dye congo red (CR) from aqueous solutions using an anion exchange membrane (EBTAC) has been investigated at room temperature. The effect of several factors including contact time, membrane dosage, ionic strength and temperature were studied. Kinetic models, namely pseudo-first-order and pseudo-second-order, liquid film diffusion and Elovich models as well as Bangham and modified freundlich Equations, were employed to evaluate the experimental results. Parameters such as adsorption capacities, rate constant and related correlation coefficients for every model were calculated and discussed. The adsorption of CR on anion exchange membranes followed pseudo-second-order Kinetics. Thermodynamic parameters, namely changes in Gibbs free energy ( ∆G° ), enthalpy ( ∆H° ) and entropy ( ∆S° ) were calculated for the adsorption of congo red, indicating an exothermic process.

Removal of Congo Red from Aqueous Solution by Anion Exchange Membrane (EBTAC): Adsorption Kinetics and Themodynamics

PubMed Central

Khan, Muhammad Imran; Akhtar, Shahbaz; Zafar, Shagufta; Shaheen, Aqeela; Khan, Muhammad Ali; Luque, Rafael; ur Rehman, Aziz

2015-01-01

The adsorption behavior of anionic dye congo red (CR) from aqueous solutions using an anion exchange membrane (EBTAC) has been investigated at room temperature. The effect of several factors including contact time, membrane dosage, ionic strength and temperature were studied. Kinetic models, namely pseudo-first-order and pseudo-second-order, liquid film diffusion and Elovich models as well as Bangham and modified freundlich Equations, were employed to evaluate the experimental results. Parameters such as adsorption capacities, rate constant and related correlation coefficients for every model were calculated and discussed. The adsorption of CR on anion exchange membranes followed pseudo-second-order Kinetics. Thermodynamic parameters, namely changes in Gibbs free energy (∆G°), enthalpy (∆H°) and entropy (∆S°) were calculated for the adsorption of congo red, indicating an exothermic process. PMID:28793430

Congo red dye affects survival and reproduction in the cladoceran Ceriodaphnia dubia. Effects of direct and dietary exposure.

PubMed

Hernández-Zamora, Miriam; Martínez-Jerónimo, Fernando; Cristiani-Urbina, Eliseo; Cañizares-Villanueva, Rosa Olivia

2016-12-01

Nearly 7 00000 tons of dyes are produced annually throughout the world. Azo dyes are widely used in the textile and paper industries due to their low cost and ease of application. Their extensive use results in large volumes of wastewater being discharged into aquatic ecosystems. Large volume discharges constitute a health risk since many of these dyes, such as Congo Red, are elaborated with benzidine, a known carcinogenic compound. Information regarding dye toxicity in aquatic ecosystems is limited. Therefore, the aim of the present study was to evaluate the effect of Congo Red on survival and reproduction of Ceriodaphnia dubia. We determined the 48 h median lethal concentration (LC 50 ) and evaluated the effects of sublethal concentrations in subchronic exposures by using as food either fresh algae or algae previously exposed to the dye. LC 50 was 13.58 mg L -1 . In subchronic assays, survival was reduced to 80 and 55 %, and fertility to 40 and 70 %, as compared to the control, in C. dubia fed with intoxicated cells or with the mix of intoxicated + fresh algae, respectively, so the quantity and type of food had a significant effect. We determined that Congo Red is highly toxic to C. dubia since it inhibits survival and fertility in concentrations exceeding 3 mg L -1 . Our results show that this dye produces negative effects at very low concentrations. Furthermore, our findings warn of the risk associated with discharging dyes into aquatic environments. Lastly, the results emphasize the need to regulate the discharge of effluents containing azo dyes.

Media composition and incubation temperature affect Congo red dye affinity of Shiga toxin-producing Escherichia coli

USDA-ARS?s Scientific Manuscript database

Background: Escherichia coli biofilm formation is dependent on curli fimbriae and cellulose, and the expression of both varies among Shiga toxin-producing E. coli (STEC). Curli and cellulose expression are often identified by their affinity for Congo red dye (CR) but media composition and incubation...

Photocatalytic degradation and photo-Fenton oxidation of Congo red dye pollutants in water using natural chromite—response surface optimization

NASA Astrophysics Data System (ADS)

Shaban, Mohamed; Abukhadra, Mostafa R.; Ibrahim, Suzan S.; Shahien, Mohamed. G.

2017-12-01

Refined natural Fe-chromite was characterized by XRD, FT-IR, reflected polarized microscope, XRF and UV spectrophotometer. Photocatalytic degradation and photo-Fenton oxidation of Congo red dye by Fe-chromite was investigated using 1 mL H2O2. The degradation of dye was studied as a function of illumination time, chromite mass, initial dye concentration, and pH. Fe-chromite acts as binary oxide system from chromium oxide and ferrous oxide. Thus, it exhibits photocatalytic properties under UV illumination and photo-Fenton oxidation after addition of H2O2. The degradation in the presence of H2O2 reached the equilibrium stage after 8 h (59.4%) but in the absence of H2O2 continued to 12 h (54.6%). Photocatalytic degradation results fitted well with zero, first order and second order kinetic model but it represented by second order rather than by the other models. While the photo-Fenton oxidation show medium fitting with the second order kinetic model only. The values of kinetic rate constants for the photo-Fenton oxidation were greater than those for the photocatalytic degradation. Thus, degradation of Congo red dye using chromite as catalyst is more efficient by photo-Fenton oxidation. Based on the response surface analysis, the predicted optimal conditions for maximum removal of Congo red dye by photocatalytic degradation (100%) were 12 mg/l, 0.14 g, 3, and 11 h for dye concentration, chromite mass, pH, and illumination time, respectively. Moreover, the optimum condition for photo-Fenton oxidation of dye (100%) is 13.5 mg/l, 0.10 g, 4, and 10 h, respectively.

Tuning the band gap of TiO2 by tungsten doping for efficient UV and visible photodegradation of Congo red dye.

PubMed

Ullah, Irfan; Haider, Ali; Khalid, Nasir; Ali, Saqib; Ahmed, Sajjad; Khan, Yaqoob; Ahmed, Nisar; Zubair, Muhammad

2018-06-13

Tungsten-doped TiO 2 (W@TiO 2 ) nanoparticles, with different percentages of atomic tungsten dopant levels (range of 0 to 6 mol%) have been synthesized by the sol-gel method and characterized by UV-Visible spectroscopy, XRD, SEM, EDX, ICP-OES and XPS analysis. By means of UV-Vis spectroscopy, it has been observed that with 6 mol% tungsten doping the wavelength range of excitation of TiO 2 has extended to the visible portion of spectrum. Therefore, we evaluated the photocatalytic activity of W@TiO 2 catalysts for the degradation of Congo red dye under varying experimental parameters such as dopant concentration, catalyst dosage, dye concentrations and pH. Moreover, 6 mol% W@TiO 2 catalyst was deposited on a glass substrate to form thin film using spin coating technique in order to make the photocatalyst effortlessly reusable with approximately same efficiency. The results compared with standard titania, Degussa P25 both in UV- and visible light, suggest that 6 mol% W@TiO 2 can be a cost-effective choice for visible light induced photocatalytic degradation of Congo red dye. Copyright © 2018 Elsevier B.V. All rights reserved.

Preparation and Characterization of Dabco (1,4-Diazabicyclo [2.2.2]octane) modified bentonite: Application for Congo red removal

NASA Astrophysics Data System (ADS)

Taher, Tarmizi; Rohendi, Dedi; Mohadi, Risfidian; Lesbani, Aldes

2018-01-01

Natural bentonite provided from Sarolangun deposit was modified with 1,4-Diazabicyclo[2.2.2]octane (Dabco) to form a new class of porous material. Prior further modification, the natural bentonite was cleaned up and activated by NaCl to remove the impurities and increase the bentonite nature. Dabco modified bentonite (Dabco-bent) was prepared by exchanging the inorganic cation placed in the interlayer space of the montmorillonite mineral structure with the 0.01 M Dabco1+ at pH 6. The modified bentonite products were characterized using X-Ray powder diffraction and FT-IR to monitor the change of the bentonite crystallinity and function group due to the modification process. The XRD result confirmed that during the modification process, the d(001) of smectite peak at 2q around 6° was shifted. After the modification, the d(001) reflection of the montmorillonite interlayer was shifted 0.36° to the left indicating that the interlayer space of the montmorillonite has been expanded during the modification process. The FTIR spectra of Dabco modified bentonite exhibit no significantly different with the host bentonite. However, the presence of the new band at the wavenumber around 3000 and 2800 cm-1 indicates that the Dabco molecule has been successfully inserted to the bentonite molecule. The Congo red adsorption experiment was performed onto Dabco-bent product by batch technique. The experiment data described that kinetic model for Congo red adsorption onto Dabco-bent was adequately followed the second-order kinetic model and well described by Freundlich adsorption isotherm model.

Removal of toxic Congo red dye from water employing low-cost coconut residual fiber.

PubMed

Rani, K C; Naik, Aduja; Chaurasiya, Ram Saran; Raghavarao, K S M S

2017-05-01

The coconut residual fiber (CRF) is the major byproduct obtained during production of virgin coconut oil. Its application as a biosorbent for adsorption of Congo red was investigated. The CRF was subjected to different pretreatments, namely, pressure cooking, hexane treatment, acid treatment and their combinations. The pretreatment of CRF with the combination of hexane, acid, and pressure cooking resulted in the highest degree of adsorption. The equilibrium data were analyzed and found to fit best to both Langmuir and Freundlich isotherms. Thermodynamic parameters such as standard free energy (ΔG 0 kJ mol -1 ), standard enthalpy (ΔH 0 , kJ mol -1 ) and standard entropy (ΔS 0 , kJ mol -1 K -1 ) of the systems were calculated by using the Langmuir constant. The ΔG 0 , ΔH 0 and ΔS 0 were found to be 16.51 kJ mol -1 , -19.39 kJ mol -1 and -0.12 kJ mol -1 K -1 , respectively, at 300 K. These thermodynamic parameters suggest the present adsorption process to be non-spontaneous and exothermic. The adsorption process was observed to follow pseudo-second-order kinetics. The results suggest that CRF has potential to be a biosorbent for the removal of hazardous material (Congo red dye) with a maximum adsorption capacity of 128.94 mg g -1 at 300 K.

Adsorptive removal of an anionic dye Congo red by flower-like hierarchical magnesium oxide (MgO)-graphene oxide composite microspheres

NASA Astrophysics Data System (ADS)

Xu, Jing; Xu, Difa; Zhu, Bicheng; Cheng, Bei; Jiang, Chuanjia

2018-03-01

Flower-like magnesium oxide (MgO) microspheres and MgO-graphene oxide (GO) composites with an average diameter of 500 nm and hierarchical structure were synthesized through an ethylene glycol-mediated self-assembly process. The adsorption of Congo red (CR) by the prepared samples was evaluated in water under ambient conditions. The equilibrium adsorption isotherms of CR on the as-prepared samples could be described by the Langmuir model. The MgO-GO microspheres prepared with 0.5 wt% GO showed higher adsorption capacity (237.0 mg/g) than the MgO microspheres (227.7 mg/g). Adsorption kinetics results of CR indicated that pseudo-second-order kinetic equation could well explain the adsorption kinetics behaviors of CR. These findings indicate that the MgO-GO composite microspheres are potential adsorbents for effective removal of Congo red from wastewater.

Highly enhanced adsorption of Congo red by functionalized finger-citron-leaf-based porous carbon.

PubMed

Zhao, Gui-Hua; Fang, Yao-Yao; Dai, Wei; Ma, Na

2018-01-01

A novel high-performance porous carbon material, lanthanum(III)-doped finger-citron-leaf-based porous carbon (La/FPC), has been synthesized and used as an adsorbent for anion dye Congo red (CR). The La/FPC was characterized by nitrogen adsorption and desorption isotherms, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The adsorption performance of CR by the FPC and La/FPC composites with different contents of lanthanum(III) were evaluated in fixed-bed breakthrough experiments and batch tests at room temperature (298 K). The La/FPC had a high CR uptake capacity, which was superior to those previously reported for other adsorbents. The La/FPC sorbents can be easily regenerated using an ethanol elution technique, and after five cycles the reused La/FPC maintained about 98% of its original CR adsorption capacity. The adsorption kinetics of CR onto the lanthanum(III)-doped FPCs followed a pseudo-second-order kinetic model and fitted well with a Langmuir adsorption isotherm. La/FPC is a promising adsorbent for the removal of the anionic dyes from wastewater.

Congo red staining on 1 micron de-plasticized sections for detection of lesions in Alzheimer's disease and related disorders.

PubMed

Snow, A D; Mar, H; Nochlin, D; Wight, T N

1989-01-01

Neuritic plaques (NPs), neurofibrillary tangles (NFTs) and congophilic angiopathy (CA), the three characteristic lesions in Alzheimer's disease, are easily detected in paraffin sections using light microscopy and specific staining methods including Congo red and Thioflavin S. Identification of these lesions in plastic thick sections (1 micron) is more tedious and relies essentially on morphological criteria. This causes investigators to subsequently analyze large numbers of thin sections under the electron microscope. Since many researchers use electron microscopy for various aspects of Alzheimer's disease and related research, it would be advantageous to have a rapid method enabling the investigator to quickly and reliably identify in thick sections the characteristic NPs, NFTs and/or CA, which can then be used for further analysis at the ultrastructural level. In this context, the present study describes a dependable technique for identifying NPs, NFTs and/or CA in Alzheimer's disease and related disorders and involves Congo red staining on one micron sections after plastic removal.

New insight of hybrid membrane to degrade Congo red and Reactive yellow under sunlight.

PubMed

Rajeswari, A; Jackcina Stobel Christy, E; Pius, Anitha

2018-02-01

A study was carried out to investigate the degradation of organic contaminants (Congo red and Reactive yellow - 105) using cellulose acetate - polystyrene (CA-PS) membrane with and without ZnO impregnation. Scanning electron microscope (SEM), electron dispersive analysis of X-rays (EDAX), Fourier transform infrared spectrometer (FTIR), atomic force microscope (AFM) and thermogravimeric analysis (TG-DTA) analysis were carried out to characterize bare and ZnO impregnated CA-PS membranes. Membrane efficiency was also tested for pure water flux and antifouling performance. The modified membrane showed almost 85% water flux recovery. Blending of ZnO nanoparticles to CA-PS matrix could decrease membrane fouling and increase permeation quality of the membrane with above 90% of photocatalytic degradation efficiency for dyes. The rate of degradation of dyes was observed using UV-Vis spectrometer. Reusability of CA-PS-ZnO membrane was studied and no significant change was noted in the degradation efficiency until fourth cycle. Langmuir-Hinshelwood kinetic model well describes the photo degradation capacity and the degradation of dyes CR and RY - 105 exhibited pseudo-first order kinetics. The regression coefficient (R) of CR and RY - 105 found to be 0.99. The novelty of the prepared CA-PS-ZnO membrane is that it has better efficiency and high thermal stability than our previously reported material. Therefore, ZnO impregnated CA-PS membrane had proved to be an innovative alternative for the degradation of CR and RY - 105 dyes. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation of magnetic imprinted graphene oxide composite for catalytic degradation of Congo red under dark ambient conditions.

PubMed

Yang, Xiaochao; You, Xiaoxiao; Zhang, Bin; Guo, Chuigen; Yu, Chaosheng

2017-10-01

Magnetic imprinted N-doped P25/Fe 3 O 4 -graphene oxide (MIGNT) was prepared with methyl orange as the dummy template and pyrrole as functional monomer for catalytic degradation of Congo red (CR). Hummers method and the hydrothermal method were used to synthesize Fe 3 O 4 -GO and N-doped P25, respectively. The results of adsorption and degradation experiments showed that the adsorption capacity and catalytic degradation ability of the imprinted composite for CR were obviously higher than those of a non-imprinted one. Moreover, the effect factors on degradation efficiency of CR, such as the initial concentration of CR, catalysis time, pH of the solution and temperature, were investigated. The MIGNT was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, a physical property measurement system and a thermal gravimetric analyzer. The degradation products of CR were detected with high performance liquid chromatography and a mass spectrometer. The MIGNT was a brand-new imprinted composite and had high degradation efficiency for CR under dark ambient conditions. The MIGNT could be recycled conveniently, due to its magnetic property, and could be used as an effective, environmentally friendly and low-cost catalytic degradation material for the treatment of water contaminated by CR.

Ultra-high adsorption capacity of MgO/SiO2 composites with rough surfaces for Congo red removal from water.

PubMed

Hu, Mengqing; Yan, Xinlong; Hu, Xiaoyan; Zhang, Jiajin; Feng, Rui; Zhou, Min

2018-01-15

Due to its high isoelectric point, relative safety and low environmental toxicity, magnesium oxide has attracted much attention for its role in the removal of toxic dyes from wastewater. Herein, MgO-SiO 2 composites with rough surfaces were synthesized by a one-step method. The as-prepared composites were characterized for the adsorption of Congo red from water using adsorption kinetics and isotherms. The adsorption capacity of the 20% MgO-SiO 2 sample could be as high as ∼4000mg/g at 25°C, which is the highest value reported to date. The adsorption process of Congo red on the as-synthesized samples obeyed the Langmuir adsorption model. The MgO-SiO 2 composite sample could be regenerated by calcination, and the regeneration efficiency remained for up to 5 cycles of the regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

Hierarchical NiO-SiO2 composite hollow microspheres with enhanced adsorption affinity towards Congo red in water.

PubMed

Lei, Chunsheng; Zhu, Xiaofeng; Zhu, Bicheng; Yu, Jiaguo; Ho, Wingkei

2016-03-15

Hollow microspheres and hierarchical porous nanostructured materials with desired morphologies have gained remarkable attention for their potential applications in environmental technology. In this study, NiO-SiO2 hollow microspheres were prepared by co-precipitation with SiO2 and nickel salt as precursors, followed by dipping in alkaline solution and calcination. The samples were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, nitrogen adsorption, and X-ray photoelectron spectroscopy. The synthesized hollow spheres were composed of a SiO2 shell and hierarchical porous NiO nanosheets on the surface. Adsorption experiments suggested that NiO-SiO2 composite particles were powerful adsorbents for removal of Congo red from water, with a maximum adsorption capacity of 204.1 mg/g. The high specific surface areas, hollow structures, and hierarchical porous surfaces of the hollow composite particles are suitable for various applications, including adsorption of pollutants, chemical separation, and water purification. Copyright © 2015 Elsevier Inc. All rights reserved.

Luminescent properties of Cr-doped (GdX, Y1-X)3Al5O12 infra-red scintillator crystals

NASA Astrophysics Data System (ADS)

Suzuki, Akira; Kurosawa, Shunsuke; Yamaji, Akihiro; Shoji, Yasuhiro; Pejchal, Jan; Kamada, Kei; Yokota, Yuui; Yoshikawa, Akira

2014-10-01

Cr-doped (GdX Y1-X)3Al5O12 (X = 0, 0.25, 0.50) crystals prepared by the micro-pulling down method were investigated to develop a infra-red scintillator for implantable patient dosimeter in radiation therapy. In order to evaluate their optical and scintillation performance, the following properties were measured: (i) transmittance between ultra-violet and near-infra red region, (ii) photoluminescence spectra under Xe-lamp excitation, and (iii) X-ray excited radio-luminescence spectra. Cr:Y3Al5O12 and Cr:(Gd0.25 Y0.75)3Al5O12 crystals showed increased transmittance of 80%, while Cr:(Gd0.50 Y0.50)3Al5O12 had a lower transmittance of 40% due to its polycrystalline structure. In addition, all the Cr:(GdX Y1-X)3Al5O12 crystals showed sharp scintillation luminescence peaks ascribed to Cr3+ d-d transitions. Therefore, these results suggested that Cr:Y3Al5O12 and Cr:(Gd0.25 Y0.75)3Al5O12 crystals can be candidate materials for the dosimeter use.

Preparation of low cost activated carbon from Myrtus communis and pomegranate and their efficient application for removal of Congo red from aqueous solution.

PubMed

Ghaedi, Mehrorang; Tavallali, Hossein; Sharifi, Mahdi; Kokhdan, Syamak Nasiri; Asghari, Alireza

2012-02-01

In this research, the potential applicability of activated carbon prepared from Myrtus communis (AC-MC) and pomegranate (AC-PG) as useful adsorbents for the removal of Congo red (CR) from aqueous solutions in batch method was investigated. The effects of pH, contact time, agitation time and amount of adsorbents on removal percentage of Congo red on both adsorbents were examined. Increase in pH up to 6 for AC-MC and pH 7 for AC-PG increase the adsorption percentage (capacity) and reach equilibrium within 30 min of contact time. Fitting the experimental data to conventional isotherm models like Freundlich, Langmuir, Tempkin and Dubinin-Radushkevich show that the experimental data fitted very well to the Freundlich isotherm for AC-MC and Langmuir isotherm for AC-PG. Fitting the experimental data to different kinetic models such as pseudo first-order, pseudo second-order, Elovich and intraparticle diffusion mechanism showed the applicability of a pseudo second-order with involvement of intraparticle diffusion model for interpretation of experimental data for both adsorbents. The adsorption capacity of AC-PG and AC-MC for the removal of CR was found to be 19.231 and 10 mg g(-1). These results clearly indicate the efficiency of adsorbents as a low cost adsorbent for treatment of wastewater containing CR. Copyright © 2011 Elsevier B.V. All rights reserved.

Congo red adsorption from aqueous solutions by using chitosan hydrogel beads impregnated with nonionic or anionic surfactant.

PubMed

Chatterjee, Sudipta; Lee, Dae S; Lee, Min W; Woo, Seung H

2009-09-01

The adsorption performance of CS beads impregnated with triton X-100 (TX-100) as a nonionic surfactant and sodium dodecyl sulfate (SDS) as an anionic surfactant was investigated for the removal of anionic dye (congo red) from aqueous solution. While the adsorption capacity of CS/TX-100 beads was enhanced at all concentrations of TX-100 (0.005-0.1%), the increase in the concentration of SDS above 0.01% in the CS/SDS beads gradually reduced the adsorption capacity of the beads. Equilibrium adsorption isotherm data indicated a good fit to the Sips isotherm model and a heterogeneous adsorption process. The Sips maximum adsorption capacity in dry weight of the CS/TX-100 beads was 378.79 mg/g and 318.47 mg/g for the CS/SDS beads, higher than the 223.25mg/g of the CS beads. Modification of CS beads by impregnation with nonionic surfactant, or even anionic surfactant, at low concentrations is a possible way to enhance adsorption of anionic dye.

Discoloration and detoxicification of a Congo red dye solution by means of ozone treatment for a possible water reuse.

PubMed

Khadhraoui, M; Trabelsi, H; Ksibi, M; Bouguerra, S; Elleuch, B

2009-01-30

The objective of this study was to investigate the degradation and mineralization of an azo-dye, the Congo red, in aqueous solutions using ozone. Phytotoxicity and the inhibitory effects on the microbial activity of the raw and the ozonated solutions were also carried out with the aim of water reuse and environment protection. Decolorization of the aqueous solutions, disappearance of the parent compound, chemical oxygen demand (COD) and total organic carbon (TOC) removal were the main parameters monitored in this study. To control the mineralization of the Congo red, pH of the ozonated solution and heteroatoms released from the mother molecule such NH(4)(+), NO(3)(-) and SO(4)(2-) were determined. It was concluded that ozone by itself is strong enough to decolorize these aqueous solutions in the early stage of the oxidation process. Nonetheless, efficient mineralization had not been achieved. Significant drops in COD (54%) were registered. The extent of TOC removal was about 32%. Sulfur heteroatom was totally oxidized to SO(4)(2-) ions while the central -NN- azo ring was partially converted to NH(4)(+) and NO(3)(-). Results of the kinetic studies showed that ozonation of the selected molecule was a pseudo-first-order reaction with respect to dye concentration. The obtained results also demonstrate that ozone process reduced the phytotoxicity of the raw solution and enhanced the biodegradability of the treated azo-dyes-wastewater. Hence, this show that ozone remains one of the effective technologies for the discoloration and the detoxification of organic dyes in wastewater.

Rapid degradation of Congo red by molecularly imprinted polypyrrole-coated magnetic TiO2 nanoparticles in dark at ambient conditions.

PubMed

Wei, Shoutai; Hu, Xiaolei; Liu, Hualong; Wang, Qiang; He, Chiyang

2015-08-30

A novel molecularly imprinted polymer (MIP)-coated magnetic TiO2 nanocomposite was prepared, using methyl orange (MO) as the dummy template and pyrrole as functional monomer, for degradation of Congo red (CR). The nanocomposite was characterized by Fourier transform infrared spectroscopy, thermo-gravimetric analysis, X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. The imprinting efficiency of the imprinted nanoparticles was investigated by static binding test, and their degradation ability toward CR was also studied. Moreover, the effects of pH, temperature, dissolved oxygen and oscillation rate on degradation rate of CR were investigated. Results showed that the imprinted nanocomposite had higher adsorption ability for MO compared with the non-imprinted one. Moreover, it could degrade CR rapidly in dark at room temperature and atmospheric pressure and could be recycled easily by a magnet with a good reusability. A degradation mechanism was proposed according to LC-MS analysis of degradation products of CR. The new imprinted nanoparticles showed high catalytic activity at ambient conditions without light illumination and additional chemicals, and therefore, it can be potentially applied to the rapid, "green" and low-cost degradation of CR in industrial printing and dyeing wastewater. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of Congo red on the drag reduction properties of poly(ethylene oxide) in aqueous solution based on drop impact images.

PubMed

Alkschbirs, Melissa I; Bizotto, Vanessa C; de Oliveira, Marcelo G; Sabadini, Edvaldo

2004-12-21

The presence of very small amounts (ppm) of high-MW polymers in solution produces high levels of drag reduction in a turbulent flow. This phenomenon, often termed as the Toms effect, is highly dependent not only on MW, but also on the flexibility of the macromolecular chain. The Toms effect can be studied through the images of the structures produced after the drop impact against shallow solution surfaces. The splash structures composed of crown, cavity, and Rayleigh jet are highly dependent on the elongational properties of the solution. This work presents the effects of Congo red on the drag reduction properties of poly(ethylene oxide) in aqueous solutions through the analysis of splash structures. Results obtained in this analysis indicate that Congo red molecules act as physical cross-linking agents, decreasing the polymer elasticity and its drag reduction capacity. It was observed that the maximum height of the Rayleigh jet can be used as a sensitive parameter to the complexation between the dye and the polymer molecules.

EDTA functionalized magnetic nanoparticle as a multifunctional adsorbent for Congo red dye from contaminated water

NASA Astrophysics Data System (ADS)

Sahoo, Jitendra Kumar; Rath, Juhi; Dash, Priyabrat; Sahoo, Harekrushna

2017-05-01

The present work reports the applicability of magnetite iron nanoparticles (Fe3O4) functionalized with ethylenediaminetetraacetic acid (EDTA) as an efficient adsorbent for the removal of Congo red (CR) dye from contaminated water. Magnetic nanoparticles (Fe3O4) are prepared by chemical precipitation method in which Fe2+ and Fe3+ salt from aqueous solution were reacted in presence of ammonia solution. The surface of Fe3O4 nanoparticle was first coated with (3-aminopropyl) triethoxy silane (APTES) by a salinization reaction and then linked with EDTA via reaction between -NH2 and -COOH to form well dispersed surface functionalised biocompatible magnetic nanoparticles. The obtained EDTA functionalized magnetic nanoparticles are characterized in terms of their morphological, XRD, BET surface area analysis, Fourier transform infrared spectroscopy (FT-IR) and Vibrating sample magnetometer (VSM). The adsorption of CR on Fe3O4-APTES-EDTA nanocomposite corresponds well to the Langmuir model and the Freundlich model respectively. The adsorption processes for CR followed the pseudo-second-order model.

Photocatalytic degradation using design of experiments: a review and example of the Congo red degradation.

PubMed

Sakkas, Vasilios A; Islam, Md Azharul; Stalikas, Constantine; Albanis, Triantafyllos A

2010-03-15

The use of chemometric methods such as response surface methodology (RSM) based on statistical design of experiments (DOEs) is becoming increasingly widespread in several sciences such as analytical chemistry, engineering and environmental chemistry. Applied catalysis, is certainly not the exception. It is clear that photocatalytic processes mated with chemometric experimental design play a crucial role in the ability of reaching the optimum of the catalytic reactions. The present article reviews the major applications of RSM in modern experimental design combined with photocatalytic degradation processes. Moreover, the theoretical principles and designs that enable to obtain a polynomial regression equation, which expresses the influence of process parameters on the response are thoroughly discussed. An original experimental work, the photocatalytic degradation of the dye Congo red (CR) using TiO(2) suspensions and H(2)O(2), in natural surface water (river water) is comprehensively described as a case study, in order to provide sufficient guidelines to deal with this subject, in a rational and integrated way. (c) 2009 Elsevier B.V. All rights reserved.

Hierarchical flower-like nickel(II) oxide microspheres with high adsorption capacity of Congo red in water.

PubMed

Zheng, Yingqiu; Zhu, Bicheng; Chen, Hua; You, Wei; Jiang, Chuanjia; Yu, Jiaguo

2017-10-15

Monodispersed hierarchical flower-like nickel(II) oxide (NiO) microspheres were fabricated by a facile solvothermal reaction with the assistance of ethanolamine and a subsequent calcination process. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption isotherms, zeta potential measurement and Fourier transform infrared spectroscopy. Flower-like nickel(II) hydroxide microspheres with uniform diameters of approximate 6.3μm were obtained after the solvothermal reaction. After heat treatment at 350°C, the crystal phase transformed to NiO, but the hierarchical porous structure was maintained. The as-prepared microspheres exhibited outstanding performance for the adsorption of Congo red (CR), an anionic organic dye, from aqueous solution at circumneutral pH. The pseudo-second-order model can make a good description of the adsorption kinetics, while Langmuir model could well express the adsorption isotherms, with calculated maximum CR adsorption capacity of 534.8 and 384.6mgg -1 , respectively, for NiO and Ni(OH) 2 . The adsorption mechanism of CR onto the as-synthesized samples can be mainly attributed to electrostatic interaction between the positively charged sample surface and the anionic CR molecules. The as-prepared NiO microspheres are a promising adsorbent for CR removal in water treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

Structural and photoluminescence properties of stannate based displaced pyrochlore-type red phosphors: Ca(3-x)Sn₃Nb₂O₁₄:xEu³⁺.

PubMed

Sreena, T S; Prabhakar Rao, P; Francis, T Linda; Raj, Athira K V; Babu, Parvathi S

2015-05-14

New stannate based displaced pyrochlore-type red phosphors, Ca(3-x)Sn3Nb2O14:xEu(3+), were prepared via a conventional solid state method. The influence of partial occupancy of Sn in both A and B sites of the pyrochlore-type oxides on the photoluminescence properties was studied using powder X-ray diffraction, FT-Raman, transmission electron microscopy, scanning electron microscopy with energy dispersive spectrometry, UV-visible absorption spectroscopy, and photoluminescence excitation and emission spectra with lifetime measurements. The structural analysis establishes that these oxides belong to a cubic displaced pyrochlore type structure with a space group Fd3̄m. These phosphors exhibit strong absorptions at near UV and blue wavelength regions and emit intense multiband emissions due to Eu(3+ 5)D0-(7)F(0, 1, 2) transitions. The absence of characteristic MD transition splitting points out that local cation disorder exists in this type of displaced pyrochlores, reducing the D(3d) inversion symmetry, which is not evidenced by such disorder in the X-ray diffraction analysis. The unusual forbidden intense sharp (5)D0-(7)F0 transition indicates single site occupancy of Eu(3+) with a narrower range of bonding environment, preventing the cluster formation. This is supported by the stable (5)D0 lifetime with Eu(3+) concentration. The Judd-Ofelt intensity parameter assessment corroborates these results. The CIE color coordinates of these phosphors were found to be (0.60, 0.40), which are close to the NTSC standard values (0.67, 0.33) for a potential red phosphor.

Selective high capacity adsorption of Congo red, luminescence and antibacterial assessment of two new cadmium(II) coordination polymers

NASA Astrophysics Data System (ADS)

Beheshti, Azizolla; Nozarian, Kimia; Ghamari, Narges; Mayer, Peter; Motamedi, Hossein

2018-02-01

Coordination polymers [CdCl(NCS)L]n (1) and {[Cd2I4(L)2]·H2O·DMF}n (2) (where L = 1, 1-(1,4-butanediyl)bis(1,3-dihydro-3-methyl-1H-imidazole- 2-thione)) were synthesized and structurally characterized. Compounds 1 and 2 both possess a tetrahedral arrangement with CdS2NCl and CdS2I2 cores, respectively. In these structures, the flexible thione ligands adopt a μ- bridging coordination mode to form 1D chains along the b-axis. The 1D chains are join together by C-H--Cl hydrogen bonds (in 1) and water molecules (in 2) to create a 2D supramolecular framework with an ABAB…packing mode. Remarkably, compounds 1 and 2 in particular polymer 1 exhibit excellent capacity to adsorb Congo red (CR) with high selectivity. The experimental data demonstrate that the mechanism of sorption process can be described by the Elovich and pseudo second order kinetic models for 1 and 2, respectively. Furthermore, the possible mechanism of CR absorption was investigated by UV-Vis and solid state fluorescence spectra for the title polymers. In addition, the antibacterial assessment of these compounds have also been studied.

Preparation of porous 2,3-dialdehyde cellulose beads crosslinked with chitosan and their application in adsorption of Congo red dye.

PubMed

Ruan, Chang-Qing; Strømme, Maria; Lindh, Jonas

2018-02-01

Micrometer sized 2,3-dialdehyde cellulose (DAC) beads were produced via a recently developed method relying on periodate oxidation of Cladophora nanocellulose. The produced dialdehyde groups and pristine hydroxyl groups provided the DAC beads with a vast potential for further functionalization. The sensitivity of the DAC beads to alkaline conditions, however, limits their possible functionalization and applications. Hence, alkaline-stable and porous cellulose beads were prepared via a reductive amination crosslinking reaction between 2,3-dialdehyde cellulose beads and chitosan. The produced materials were thoroughly characterized with different methods. The reaction conditions, including the amount of chitosan used, conditions for reductive amination, reaction temperature and time, were investigated and the maintained morphology of the beads after exposure to 1M NaOH (aq.) was verified with SEM. Different washing and drying procedures were used and the results were studied by SEM and BET analysis. Furthermore, FTIR, TGA, EDX, XPS, DLS and elemental analysis were performed to characterize the properties of the prepared beads. Finally, the alkaline-stable porous chitosan cross-linked 2,3-dialdehyde cellulose beads were applied as adsorbent for the dye Congo red. The crosslinked beads displayed fast and high adsorption capacity at pH 2 and good desorption properties at pH 12, providing a promising sorption material. Copyright © 2017 Elsevier Ltd. All rights reserved.

Kinetics and thermodynamics of bovine serum albumin interactions with Congo red dye.

PubMed

de Paula, Hauster Maximiler Campos; Coelho, Yara Luiza; Agudelo, Alvaro Javier Patiño; Rezende, Jaqueline de Paula; Ferreira, Gabriel Max Dias; Ferreira, Guilherme Max Dias; Pires, Ana Clarissa Dos Santos; da Silva, Luis Henrique Mendes

2017-11-01

To optimize the therapeutic applications of Congo red (CR), a potential inhibitor of protein aggregation, the kinetics and thermodynamics of the interactions between CR and a model protein need to be understood. We used surface plasmon resonance (SPR) and fluorescence techniques to determine the dynamics and thermodynamic parameters for the formation of complexes between CR and bovine serum albumin (BSA). CR interacts with BSA through a transition complex; the activation energy for association (E act(a) ) was determined to be 35.88kJmol -1 , while the activation enthalpy (ΔH ‡ ), entropy (ΔS ‡ ), and Gibbs free energy (ΔG ‡ ) are 33.41kJmol -1 , 0.18Jmol -1 K -1 , and 33.35kJmol -1 , respectively. When this intermediate transforms into the final CR-BSA complex, the entropy of the system increases and part of the absorbed energy is released; this process is associated with a reverse activation energy (E act(d) ) of 20.17kJmol -1 , and values of ΔH ‡ , ΔS ‡ , and ΔG ‡ of 17.69kJmol -1 , -162.86Jmol -1 K -1 , and 66.25kJmol -1 , respectively. A comparison of the SPR and fluorescence results suggests that there is more than one site where BSA interacts with CR. Copyright © 2017 Elsevier B.V. All rights reserved.

Sol-gel synthesis of red-phosphors [Na xGd 1-x/3-zEu z]Mo yW 1-yO 4 powers and luminescence properties

NASA Astrophysics Data System (ADS)

Cao, Fa-Bin; Li, Liao-Sha; Tian, Yan-Wen; Gao, Zhi-Fang; Chen, Yong-Jie; Xiao, Lin-Jiu; Wu, Xing-Rong

2011-04-01

In this work, we report on the sol-gel synthesis of red-phosphors [Na xGd 1-x/3-zEu z]Mo yW 1-yO 4 powders doped with several dopants and its luminescence properties at room temperature. X-ray diffraction patters indicated that red-phosphors powders present tetragonal symmetry and cubic structure. The red-phosphors [Na xGd 1-x/3-zEu z]Mo yW 1-yO 4 powders doped exhibit characteristic of a ultraviolet visible-light emission diode. The SEM images for [ NaGdEu0.043+]Mo 0.4W 0.6O 4 phosphor exhibits irregular morphology and cottonlike shape. The size of the particles is estimated to be about 1 μm. Luminescence properties showed that the maximum emission in red region lies in the arrange of 613 nm and 617 nm.

Razor clam (Ensis directus) shell as a low-cost adsorbent for the removal of Congo red and Rhodamine B dyes from aqueous solution

NASA Astrophysics Data System (ADS)

Areibat, Lila Elamari Mohamed; Kamari, Azlan

2017-05-01

Wastewater originating from industrial effluents contains many types of pollutants including dyes. Anionic and cationic dyes are very toxic and they can cause several problems to aquatic system. In present study, razor clam shell was used as a potential adsorbent to remove two classes of dyes, namely anionic (Congo red, CR) and cationic (Rhodamine B, RB) dyes from aqueous solution. Batch adsorption experiments were performed to study the effects of three experimental parameters, namely solution pH, adsorbent dosage and initial dye concentration, on adsorption capacity of CR and RB onto razor clam shell. Results indicated that pH 2.0 was optimum pH for adsorbent to adsorb both CR and RB. At an initial concentration of 20 mg/L, the removal percentages of CR and RB were 97% and 38%, respectively. The Freundlich and Langmuir isotherm models were used to describe adsorption behaviour of CR and RB, as well as the relationship between adsorbent and adsorbate. The adsorption equilibrium data were well fitted to Freundlich isotherm model. The separation factor (RL) constants suggest that both CR and RB were favourably adsorbed by razor clam shell. Razor clam shell was characterised by using two techniques, namely Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectrometry (FTIR). Overall, this study suggests that razor clam shell has great potential to be an alternative to expensive adsorbents.

Bioremoval of the azo dye Congo Red by the microalga Chlorella vulgaris.

PubMed

Hernández-Zamora, Miriam; Cristiani-Urbina, Eliseo; Martínez-Jerónimo, Fernando; Perales-Vela, Hugo Virgilio; Ponce-Noyola, Teresa; Montes-Horcasitas, María del Carmen; Cañizares-Villanueva, Rosa Olivia

2015-07-01

Discharge of dye-containing wastewater by the textile industry can adversely affect aquatic ecosystems and human health. Bioremoval is an alternative to industrial processes for detoxifying water contaminated with dyes. In this work, active and inactive biomass of the microalga Chlorella vulgaris was assayed for the ability to remove Congo Red (CR) dye from aqueous solutions. Through biosorption and biodegradation processes, Chlorella vulgaris was able to remove 83 and 58 % of dye at concentrations of 5 and 25 mg L(-1), respectively. The maximum adsorption capacity at equilibrium was 200 mg g(-1). The Langmuir model best described the experimental equilibrium data. The acute toxicity test (48 h) with two species of cladocerans indicated that the toxicity of the dye in the effluent was significantly decreased compared to the initial concentrations in the influent. Daphnia magna was the species less sensitive to dye (EC50 = 17.0 mg L(-1)), followed by Ceriodaphnia dubia (EC50 = 3.32 mg L(-1)). These results show that Chlorella vulgaris significantly reduced the dye concentration and toxicity. Therefore, this method may be a viable option for the treatment of this type of effluent.

Synthesis of WO{sub 3} nanoparticles by citric acid-assisted precipitation and evaluation of their photocatalytic properties

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

Sánchez-Martínez, D.; Martínez-de la Cruz, A., E-mail: azael70@yahoo.com.mx; López-Cuéllar, E.

Graphical abstract: Display Omitted Highlights: ► WO{sub 3} nanoparticles were synthesized by a simple citric acid-assisted precipitation. ► WO{sub 3} photocatalyst was able to the partial mineralization of rhB, IC and MO. ► WO{sub 3} can be considered as a photocatalyst active under visible light irradiation. -- Abstract: WO{sub 3} nanoparticles were synthesized by citric acid-assisted precipitation method using a 1:1.5 molar ratio of ammonium paratungstate hydrate (H{sub 42}N{sub 10}O{sub 42}W{sub 12}·xH{sub 2}O):citric acid (C{sub 6}H{sub 8}O{sub 7}). The formation of monoclinic crystal structure of WO{sub 3} at different temperatures was confirmed by X-ray powder diffraction (XRD). The characterization ofmore » the samples synthesized was complemented by transmission electron microscopy (TEM), Brunauer–Emmitt–Teller surface area (BET) and diffuse reflectance spectroscopy (DRS). According to the thermal treatment followed during the synthesis of WO{sub 3}, the morphology of the nanoparticles formed was characterized by rectangular and ovoid shapes. The photocatalytic activity of WO{sub 3} obtained under different experimental conditions was evaluated in the degradation of rhodamine B (rhB), indigo carmine (IC), methyl orange (MO), and Congo red (CR) in aqueous solution under UV and UV–vis radiation. The highest photocatalytic activity was observed in the sample obtained by thermal treatment at 700 °C. In general, the sequence of degradation of the organic dyes was: indigo carmine (IC) > rhodamine B (rhB) > methyl orange (MO) > Congo red (CR). The mineralization degree of organic dyes by WO{sub 3} photocatalysts was determined by total organic carbon analysis (TOC) reaching percentages of mineralization of 82% (rhB), 85% (IC), 28% (MO), and 7% (CR) for 96 h of lamp irradiation.« less

Removal of Congo Red by magnetic mesoporous titanium dioxide-graphene oxide core-shell microspheres for water purification.

PubMed

Li, Leilei; Li, Xiangjun; Duan, Huimin; Wang, Xiaojiao; Luo, Chuannan

2014-06-14

Magnetic mesoporous titanium dioxide-graphene oxide (Fe3O4@mTiO2@GO) with a large surface area and a good magnetic responsiveness was synthesized by immobilizing a mesoporous titanium dioxide (mTiO2) shell on the surface of magnetic Fe3O4 nanoparticles prior to binding with graphene oxide (GO). It showed a tunable pore structure and surface properties, and was mechanically strong. The characteristic results of a Fourier transform infrared spectrometer (FTIR), a scanning electron microscope (SEM), a vibrating sample magnetometer (VSM) and X-ray diffraction (XRD) indicated that Fe3O4@mTiO2@GO has been prepared. Fe3O4@mTiO2@GO was used as an adsorbent for the removal of Congo Red (CR) from simulated wastewater with a fast solid-liquid separation in the presence of an external magnetic field. Batch adsorption experiments were performed to evaluate the adsorption conditions and reusability. The results showed that the maximum adsorption capacity was 89.95 mg g(-1), which is much higher than the previously reported values of other absorbent materials. Moreover, the Fe3O4@mTiO2@GO could be repeatedly used via simple treatment without any obvious structure and performance degradation. The adsorption kinetic data were best described by a pseudo-second-order model and the equilibrium adsorptions were well-described by the Freundlich isotherm model. The Fe3O4@mTiO2@GO may be suitable materials for use in CR pollution cleanup if synthesized on a large scale and at a low price in the near future.

Removal of anionic dye Congo red from aqueous solution by raw pine and acid-treated pine cone powder as adsorbent: equilibrium, thermodynamic, kinetics, mechanism and process design.

PubMed

Dawood, Sara; Sen, Tushar Kanti

2012-04-15

Pine cone a natural, low-cost agricultural by-product in Australia has been studied for its potential application as an adsorbent in its raw and hydrochloric acid modified form. Surface study of pine cone and treated pine cone was investigated using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The modification process leads to increases in the specific surface area and decreases mean particle sizes of acid-treated pine cone when compared to raw pine cone biomass. Batch adsorption experiments were performed to remove anionic dye Congo red from aqueous solution. It was found that the extent of Congo red adsorption by both raw pine cone biomass and acid-treated biomass increased with initial dye concentration, contact time, temperature but decreased with increasing solution pH and amount of adsorbent of the system. Overall, kinetic studies showed that the dye adsorption process followed pseudo-second-order kinetics based on pseudo-first-order and intra-particle diffusion models. The different kinetic parameters including rate constant, half-adsorption time, and diffusion coefficient were determined at different physico-chemical conditions. Equilibrium data were best represented by Freundlich isotherm model among Langmuir and Freundlich adsorption isotherm models. It was observed that the adsorption was pH dependent and the maximum adsorption of 32.65 mg/g occurred at pH of 3.55 for an initial dye concentration of 20 ppm by raw pine cone, whereas for acid-treated pine cone the maximum adsorption of 40.19 mg/g for the same experimental conditions. Freundlich constant 'n' also indicated favourable adsorption. Thermodynamic parameters such as ∆G(0), ∆H(0), and ∆S(0) were calculated. A single-stage batch absorber design for the Congo red adsorption onto pine cone biomass also presented based on the Freundlich isotherm model equation. Copyright © 2012 Elsevier Ltd. All rights reserved.

[Adsorption of Congo red from aqueous solution on hydroxyapatite].

PubMed

Zhan, Yan-Hui; Lin, Jian-Wei

2013-08-01

The adsorption of Congo red (CR) from aqueous solution on hydroxyapatite was investigated using batch experiments. The hydroxyapatite was effective for CR removal from aqueous solution. The adsorption kinetics of CR on hydroxyapatite well followed a pseudo-second-order model. The equilibrium adsorption data of CR on hydroxyapatite could be described by the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. Thermodynamic parameters such as Gibbs free energy change, enthalpy change and entropy change were calculated and showed that the adsorption of CR on hydroxyapatite was spontaneous and exothermic in nature. The CR adsorption capacity for hydroxyapatite decreased significantly with increasing pH from 8 to 10. Thermal regeneration showed that hydroxyapatite could be used for six desorption-adsorption cycles with high removal efficiency for CR in each cycle. The mechanisms for CR adsorption on hydroxyapatite with pH value below the pH at point of zero charge (pH(PZC)) include electrostatic attraction, hydrogen bonding and Lewis acid-base interaction. The mechanisms for CR adsorption on hydroxyapatite with pH value above its pH(PZC) include hydrogen bonding and Lewis acid-base interaction. Results of this work indicate that hydroxyapatite is a promising adsorbent for CR removal from aqueous solution.

Diazo dye Congo Red degradation using a Boron-doped diamond anode: An experimental study on the effect of supporting electrolytes.

PubMed

Jalife-Jacobo, H; Feria-Reyes, R; Serrano-Torres, O; Gutiérrez-Granados, S; Peralta-Hernández, Juan M

2016-12-05

Diazo dye Congo Red (CR) solutions at 100mg/L, were degraded using different supporting electrolytes in an electrochemical advanced oxidation process (EAOPs), like the anodic oxidation (AOx/BDD). All experiments were carried out in a 3L flow reactor with a Boron-doped diamond (BDD) anode and stainless steel cathode (AISI 304), at 7.5, 15, 30 and 50mA/cm(2) current densities (j). Furthermore, each experiment was carried out under a flow rate of 7L/min. Additionally, HClO4, NaCl, Na2SO4, and H2SO4 were tested as supporting electrolytes at a 50mM concentration. The degradation process was at all times considerably faster in NaCl medium. Solutions containing SO4(2-) or ClO4(-) ions were less prompted to degradation due to the low oxidation power of these species into the bulk. Dissolved organic carbon (DOC) analysis, was carried out to evaluate the mineralization of CR. The degradation of CR, was evaluated with the HPLC analysis of the treated solutions. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of the addition mode of carbon nanotubes for the production of chitosan hydrogel core-shell beads on adsorption of Congo red from aqueous solution.

PubMed

Chatterjee, Sudipta; Chatterjee, Tania; Lim, Seong-Rin; Woo, Seung H

2011-03-01

The adsorption performance of chitosan (CS) hydrogel beads (CSBs) generated by sodium dodecyl sulfate (SDS) gelation with multi-walled carbon nanotube (CNT) impregnation was investigated for Congo red removal as a model anionic dye. CNT-impregnated CSBs were prepared by four different strategies for dispersing CNTs: (a) in CS solution (CSBN1), (b) in SDS solution (CSBN2), (c) in CS solution containing cetyltrimethylammonium bromide (CTAB) (CSBN3), and (d) in SDS solution for gelation with CTAB-containing CS solution (CSBN4). It was observed from FE-SEM study that depending on nature of CNT dispersion, CNTs were found on the outer surface of CSBN2 and CSBN4 only. The adsorption capacity of the CSBs varied with the strategy used for CNT impregnation, and CSBN4 exhibited the highest maximum adsorption capacity (375.94 mg/g) from the Sips model. The lowest Sips maximum adsorption capacity by CSBN3 (121.07 mg/g) suggested significant blocking of binding sites of CS by CNT impregnation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Syntheses and luminescence study for La{sub 1−x}Eu{sub x}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O (0≤x≤0.40) and the dehydrated products β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9} (0≤x≤0.15)

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

Sun, Xiaorui; Zhou, Zhengyang; Yang, Haixia

La{sub 1−x}Eu{sub x}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O with the Eu{sup 3+}-doping upper limit of 40 atom% were synthesized hydrothermally. Thereafter, thermal treatments at 710 °C were applied to obtain β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9}. The solid solution range is even narrower, i.e. 0≤x≤0.15, due to the mismatch between La{sup 3+} and Eu{sup 3+}. The host borate system shows a typical concentration quenching effect at x=0.20 under CT excitation, and this is postponed to x=0.30 under the f−f excitation. β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9} shows a very intense absorption of charge transfer, and gives strong red emissions at 615 nm withmore » large R/O ratios (1.9–2.4). The saturation effect appears at x=0.11, which is probably due to the lattice distortion. Eu{sup 3+} luminescence was applied as the structural probe to study the local coordination environment change during the dehydration and re-crystallization processes of La{sub 0.93}Eu{sub 0.07}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O. - Highlights: • La{sub 1−x}Eu{sub x}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O (0≤x≤0.40) were prepared by hydrothermal method. • The Eu{sup 3+}-doping limit in β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9} is 15 atom% proved by powder XRD. • La{sub 1−x}Eu{sub x}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O show relatively weaker red emissions. • β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9} shows an intense CT absorption together with strong red emissions. • Eu{sup 3+} luminescence was studied when annealing La{sub 0.93}Eu{sub 0.07}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O.« less

Equilibrium isotherms, kinetics, and thermodynamics studies for congo red adsorption using calcium alginate beads impregnated with nano-goethite.

PubMed

Munagapati, Venkata Subbaiah; Kim, Dong-Su

2017-07-01

The present study is concerned with the batch adsorption of congo red (CR) from an aqueous solution using calcium alginate beads impregnated with nano-goethite (CABI nano-goethite) as an adsorbent. The optimum conditions for CR removal were determined by studying operational variables viz. pH, adsorbent dose, contact time, initial dye ion concentration and temperature. The CABI nano-goethite was characterized by Fourier transform infrared spectroscopy (FTIR), X- ray diffraction (XRD) and Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) analysis. The CR sorption data onto CABI nano-goethite were described using Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models. The results show that the best fit was achieved with the Langmuir isotherm model. The maximum adsorption capacity (181.1mg/g) of CR was occurred at pH 3.0. Kinetic studies showed that the adsorption followed a pseudo-second-order model. Desorption experiments were carried out to explore the feasibility of regenerating the adsorbent and the adsorbed CR from CABI nano-goethite. The best desorbing agent was 0.1M NaOH with an efficiency of 94% recovery. The thermodynamic parameters ΔG°, ΔH°, and ΔS° for the CR adsorption were determined by using adsorption capacities at five different temperatures (293, 303, 313, 323 and 303K). Results show that the adsorption process was endothermic and favoured at high temperature. Copyright © 2017 Elsevier Inc. All rights reserved.

Enhanced adsorption of methyl violet and congo red by using semi and full IPN of polymethacrylic acid and chitosan.

PubMed

Maity, Jayabrata; Ray, Samit Kumar

2014-04-15

Semi and full interpenetrating polymer network (IPN) type hydrogels were prepared by free radical in situ polymerization of methacrylic acid in presence of chitosan using N,N'-methylene-bis-acrylamide (MBA) and glutaraldehyde (for full IPN) as crosslinker. Several semi and full IPN type hydrogels were prepared by varying initiator and crosslinker concentration and also monomer to chitosan mass ratio. These hydrogels were characterized and used for removal of methyl violet and congo red dye from water. Isotherms and kinetics of dye adsorption were also evaluated. Copyright © 2014 Elsevier Ltd. All rights reserved.

Removal of Congo red dye from aqueous solutions using a halloysite-magnetite-based composite.

PubMed

Ferrarini, F; Bonetto, L R; Crespo, Janaina S; Giovanela, M

2016-01-01

Adsorption has been considered as one of the most effective methods to remove dyes from aqueous solutions due to its ease of operation, high efficiency and wide adaptability. In view of all these aspects, this study aimed to evaluate the adsorption capacity of a halloysite-magnetite-based composite in the removal of Congo red dye from aqueous solutions. The effects of stirring rate, pH, initial dye concentration and contact time were investigated. The results revealed that the adsorption kinetics followed the pseudo-second-order model, and equilibrium was well represented by the Brunauer-Emmett-Teller isotherm. The thermodynamic data showed that dye adsorption onto the composite was spontaneous and endothermic and occurred by physisorption. Finally, the composite could also be regenerated at least four times by calcination and was shown to be a promising adsorbent for the removal of this dye.

Theoretical Study of the B(sup 3) Sigma(sup -, sub u) - X(sup3)Sigma(sub g, sup -) and B"(sup 3)Pi(sub u) - X(sup 3)Sigma(sub g, sup -) Band Systems of S(sub 2)

NASA Technical Reports Server (NTRS)

Pradhan, Atul D.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

1995-01-01

Multireference configuration-interaction (MRCI) wavefunctions and potential energy curves have been calculated for the X(sup 3)Sigma(sub g,sup -), B(sup 3)Sigma(sub u, Sup -) and B"(sup 3)Pi((sub u) states of S(sub 2) using correlation consistent Gaussian basis sets. These wavefunctions are utilized to compute the the transition dipole moments of the B(sup 3)Sigma(sub g, sup -) - X(sup 3) Sigma(sub g, sup -) and B"(sup 3)Pi(sub u) - X(sup 3)Sigma(sub g, sup -) systems. Oscillator strengths, transition probabilities, and radiative lifetimes are computed for the X-B system and comparison is made with experimental data.

Chemical and Physical Methods to Analyze a Multicomponent Traditional Chinese Herbal Prescription Using LC-MS/MS, Electron Microscope, and Congo Red Staining

PubMed Central

Lu, Chia-Ming; Lin, Lie-Chwen; Tsai, Tung-Hu

2013-01-01

This study develops several chemical and physical methods to evaluate the quality of a traditional Chinese formulation, Jia-Wei-Xiao-Yao-San. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) coupled with electrospray ionization was used to measure the herbal biomarkers of saikosaponin A, saikosaponin D, ferulic acid, and paeoniflorin from this herbal formula. A scanning electron microscope (SEM) and light microscopy photographs with Congo red staining were used to identify the cellulose fibers if raw herbal powder had been added to the herbal pharmaceutical product. Moreover, water solubility and crude fiber content examination were used to inspect for potential herbal additives to the herbal pharmaceutical products. The results demonstrate that the contents of the herbal ingredients of saikosaponin A, saikosaponin D, ferulic acid, and paeoniflorin were around 0.351 ± 0.017, 0.136 ± 0.010, 0.140 ± 0.005, and 2.281 ± 0.406 mg/g, respectively, for this herbal pharmaceutical product. The physical examination data demonstrate that the raw herbal powder had rough, irregular, lumpy, filamentous, and elongated shapes, as well as strong Congo red staining. In addition, water solubility and crude fiber content were not consistent in the herbal pharmaceutical products. PMID:23997802

Chemical and Physical Methods to Analyze a Multicomponent Traditional Chinese Herbal Prescription Using LC-MS/MS, Electron Microscope, and Congo Red Staining.

PubMed

Lu, Chia-Ming; Hou, Mei-Ling; Lin, Lie-Chwen; Tsai, Tung-Hu

2013-01-01

This study develops several chemical and physical methods to evaluate the quality of a traditional Chinese formulation, Jia-Wei-Xiao-Yao-San. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) coupled with electrospray ionization was used to measure the herbal biomarkers of saikosaponin A, saikosaponin D, ferulic acid, and paeoniflorin from this herbal formula. A scanning electron microscope (SEM) and light microscopy photographs with Congo red staining were used to identify the cellulose fibers if raw herbal powder had been added to the herbal pharmaceutical product. Moreover, water solubility and crude fiber content examination were used to inspect for potential herbal additives to the herbal pharmaceutical products. The results demonstrate that the contents of the herbal ingredients of saikosaponin A, saikosaponin D, ferulic acid, and paeoniflorin were around 0.351 ± 0.017, 0.136 ± 0.010, 0.140 ± 0.005, and 2.281 ± 0.406 mg/g, respectively, for this herbal pharmaceutical product. The physical examination data demonstrate that the raw herbal powder had rough, irregular, lumpy, filamentous, and elongated shapes, as well as strong Congo red staining. In addition, water solubility and crude fiber content were not consistent in the herbal pharmaceutical products.

Adsorption properties of congo red from aqueous solution onto N,O-carboxymethyl-chitosan.

PubMed

Wang, Li; Wang, Aiqin

2008-03-01

N,O-carboxymethyl-chitosans (N,O-CMC) with different degree of substitution (DS) were synthesized under heterogeneous conditions by controlling the reaction temperature. The factors influencing adsorption capacity of N,O-CMC such as the DS of N,O-CMC, initial pH value of the dye solution and adsorption temperature for anionic dye congo red (CR) were investigated. Compared with chitosan (78.90 mg/g), N,O-CMC with the DS of 0.35 exhibited much higher adsorption capacity (330.62 mg/g) for CR at the same adsorption conditions. The adsorption kinetics and isotherms showed that the sorption processes were better fitted by pseudo-second-order equation and the Langmuir equation, respectively. The adsorption mechanism of N,O-CMC was also discussed by means of IR and XPS spectra. The results in this study indicated that N,O-CMC was an attractive candidate for removing CR from the dye wastewater.

New Mycobacterium tuberculosis Complex Sublineage, Brazzaville, Congo

PubMed Central

Malm, Sven; Linguissi, Laure S. Ghoma; Tekwu, Emmanuel M.; Vouvoungui, Jeannhey C.; Kohl, Thomas A.; Beckert, Patrick; Sidibe, Anissa; Rüsch-Gerdes, Sabine; Madzou-Laboum, Igor K.; Kwedi, Sylvie; Penlap Beng, Véronique; Frank, Matthias; Ntoumi, Francine

2017-01-01

Tuberculosis is a leading cause of illness and death in Congo. No data are available about the population structure and transmission dynamics of the Mycobacterium tuberculosis complex strains prevalent in this central Africa country. On the basis of single-nucleotide polymorphisms detected by whole-genome sequencing, we phylogenetically characterized 74 MTBC isolates from Brazzaville, the capital of Congo. The diversity of the study population was high; most strains belonged to the Euro-American lineage, which split into Latin American Mediterranean, Uganda I, Uganda II, Haarlem, X type, and a new dominant sublineage named Congo type (n = 26). Thirty strains were grouped in 5 clusters (each within 12 single-nucleotide polymorphisms), from which 23 belonged to the Congo type. High cluster rates and low genomic diversity indicate recent emergence and transmission of the Congo type, a new Euro-American sublineage of MTBC. PMID:28221129

New Mycobacterium tuberculosis Complex Sublineage, Brazzaville, Congo.

PubMed

Malm, Sven; Linguissi, Laure S Ghoma; Tekwu, Emmanuel M; Vouvoungui, Jeannhey C; Kohl, Thomas A; Beckert, Patrick; Sidibe, Anissa; Rüsch-Gerdes, Sabine; Madzou-Laboum, Igor K; Kwedi, Sylvie; Penlap Beng, Véronique; Frank, Matthias; Ntoumi, Francine; Niemann, Stefan

2017-03-01

Tuberculosis is a leading cause of illness and death in Congo. No data are available about the population structure and transmission dynamics of the Mycobacterium tuberculosis complex strains prevalent in this central Africa country. On the basis of single-nucleotide polymorphisms detected by whole-genome sequencing, we phylogenetically characterized 74 MTBC isolates from Brazzaville, the capital of Congo. The diversity of the study population was high; most strains belonged to the Euro-American lineage, which split into Latin American Mediterranean, Uganda I, Uganda II, Haarlem, X type, and a new dominant sublineage named Congo type (n = 26). Thirty strains were grouped in 5 clusters (each within 12 single-nucleotide polymorphisms), from which 23 belonged to the Congo type. High cluster rates and low genomic diversity indicate recent emergence and transmission of the Congo type, a new Euro-American sublineage of MTBC.

One-step synthesis of bifunctional PEGDA/TiO2 composite film by photopolymerization for the removal of Congo red

NASA Astrophysics Data System (ADS)

Wei, Yun-Yun; Sun, Xiao-Ting; Xu, Zhang-Run

2018-07-01

Wrinkled structures can provide enlarged surface areas for some living organisms to ingest nutrients. Imitating biological wrinkle structures offers an efficient way to enhance the adsorption surface for removing hazardous pollutants in wastewater. In this work, poly-(ethylene glycol) double acrylate (PEGDA)/TiO2 composite film with tunable surface wrinkles was synthesized. TiO2 nanoparticles were evenly immobilized in the PEGDA hydrogel simply by a facile photopolymerization method within 700 ms. Various wrinkle morphologies were obtained by precisely controlling UV exposure time. The composite film was characterized by X-ray diffraction, scanning electron microscopy, diffuse reflection spectroscopy, etc. Congo red was chosen as a model pollutant to demonstrate the adsorption and degradation capacity of the composite film. The experimental results showed that the introduction of wrinkled polymer improved the dispersibility of TiO2 nanoparticles. The removal efficiency reached 100% after 180-min adsorption in the darkness and 180-min UV irradiation. The composite film exhibited a much higher enrichment and photocatalysis capacity than the pure TiO2 powder, and could be developed as a reusable film for the removal of the organic pollutants in wastewater.

Boron Substituted Na 3 V 2 (P 1 -x B x O 4 ) 3 Cathode Materials with Enhanced Performance for Sodium-Ion Batteries

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

Hu, Pu; Wang, Xiaofang; Wang, Tianshi

The development of excellent performance of Na-ion batteries remains great challenge owing to the poor stability and sluggish kinetics of cathode materials. Herein, B substituted Na 3V 2P 3–xB xO 12 (0 ≤ x ≤ 1) as stable cathode materials for Na-ion battery is presented. A combined experimental and theoretical investigations on Na 3V 2P 3–xB xO 12 (0 ≤ x ≤ 1) are undertaken to reveal the evolution of crystal and electronic structures and Na storage properties associated with various concentration of B. X-ray diffraction results indicate that the crystal structure of Na 3V 2P 3–xB xO 12 (0more » ≤ x ≤ 1/3) consisted of rhombohedral Na 3V 2(PO 4) 3 with tiny shrinkage of crystal lattice. X-ray absorption spectra and the calculated crystal structures all suggest that the detailed local structural distortion of substituted materials originates from the slight reduction of V–O distances. Na 3V 2P 3-1/6B 1/6O 12 significantly enhances the structural stability and electrochemical performance, giving remarkable enhanced capacity of 100 and 70 mAh g -1 when the C-rate increases to 5 C and 10 C. Spin-polarized density functional theory (DFT) calculation reveals that, as compared with the pristine Na 3V 2(PO 4) 3, the superior electrochemical performance of the substituted materials can be attributed to the emergence of new boundary states near the band gap, lower Na + diffusion energy barriers, and higher structure stability.« less

MIL-68 (In) nano-rods for the removal of Congo red dye from aqueous solution.

PubMed

Jin, Li-Na; Qian, Xin-Ye; Wang, Jian-Guo; Aslan, Hüsnü; Dong, Mingdong

2015-09-01

MIL-68 (In) nano-rods were prepared by a facile solvothermal synthesis using NaOAc as modulator agent at 100°C for 30 min. The BET test showed that the specific surface area and pore volume of MIL-68 (In) nanorods were 1252 m(2) g(-1) and 0.80 cm(3) g(-1), respectively. The as-prepared MIL-68 (In) nanorods showed excellent adsorption capacity and rapid adsorption rate for removal of Congo red (CR) dye from water. The maximum adsorption capacity of MIL-68 (In) nanorods toward CR reached 1204 mg g(-1), much higher than MIL-68 (In) microrods and most of the previously reported adsorbents. The adsorption process of CR by MIL-68 (In) nano-rods was investigated and found to be obeying the Langmuir adsorption model in addition to pseudo-second-order rate equation. Moreover, the MIL-68 (In) nanorods showed an acceptable reusability after regeneration with ethanol. All information gives an indication that the as-prepared MIL-68 (In) nanorods show their potential as the adsorbent for highly efficient removal of CR in wastewater. Copyright © 2015 Elsevier Inc. All rights reserved.

Preparation of low cost activated carbon from Myrtus communis and pomegranate and their efficient application for removal of Congo red from aqueous solution

NASA Astrophysics Data System (ADS)

Ghaedi, Mehrorang; Tavallali, Hossein; Sharifi, Mahdi; Kokhdan, Syamak Nasiri; Asghari, Alireza

2012-02-01

In this research, the potential applicability of activated carbon prepared from Myrtus communis (AC-MC) and pomegranate (AC-PG) as useful adsorbents for the removal of Congo red (CR) from aqueous solutions in batch method was investigated. The effects of pH, contact time, agitation time and amount of adsorbents on removal percentage of Congo red on both adsorbents were examined. Increase in pH up to 6 for AC-MC and pH 7 for AC-PG increase the adsorption percentage (capacity) and reach equilibrium within 30 min of contact time. Fitting the experimental data to conventional isotherm models like Freundlich, Langmuir, Tempkin and Dubinin-Radushkevich show that the experimental data fitted very well to the Freundlich isotherm for AC-MC and Langmuir isotherm for AC-PG. Fitting the experimental data to different kinetic models such as pseudo first-order, pseudo second-order, Elovich and intraparticle diffusion mechanism showed the applicability of a pseudo second-order with involvement of intraparticle diffusion model for interpretation of experimental data for both adsorbents. The adsorption capacity of AC-PG and AC-MC for the removal of CR was found to be 19.231 and 10 mg g -1. These results clearly indicate the efficiency of adsorbents as a low cost adsorbent for treatment of wastewater containing CR.

Effects of B Addition on Glass Formation, Mechanical Properties and Corrosion Resistance of the Zr66.7- x Ni33.3B x ( x = 0, 1, 3, and 5 at.%) Metallic Glasses

NASA Astrophysics Data System (ADS)

Xu, Jing; Niu, Jiazheng; Zhang, Zitang; Ge, Wenjuan; Shang, Caiyun; Wang, Yan

2016-02-01

The effects of B addition on glass formation, mechanical properties and electrochemical corrosion of Zr66.7- x Ni33.3B x ( x = 0, 1, 3, and 5 at.%) glassy ribbons have been investigated. The results reveal that the B addition can improve the glass forming ability and obviously raise the thermal stability of the Zr-Ni-B metallic glasses. The 1 at.% B addition exhibits the most positive effect on enhancing the microhardness of Vickers-type (HV) by 13.83%. In addition, Zr63.7Ni33.3B3 possesses the best plasticity in the nanoindentation test. The electrochemical test and microstructural observation show that the moderate B addition effectively enhances the corrosion resistance of the Zr-Ni-B metallic glasses in different solutions. The 3 at.% B addition is beneficial to improve the corrosion resistance in the 0.5 M NaCl solution. But in the 1 M HCl and 2 M NaOH solutions, the better effect is induced by the 1 and 5 at.% B addition. Moreover, the Zr-Ni-B metallic glasses exhibit active dissolution behavior in the chloride- and hydrogen-containing solutions, but passivation occurs in the 2 M NaOH solution.

Hematite (α-Fe2O3) - A potential Ce4+ carrier in red mud.

PubMed

Bolanz, Ralph M; Kiefer, Stefan; Göttlicher, Jörg; Steininger, Ralph

2018-05-01

Cerium is the most abundant rare earth element (REE) within the waste product of alumina production (red mud), but its speciation in this complex material is still barely understood. Previous studies showed evidence for a correlation between Ce and the main constituent of red mud, iron oxides, which led us to investigate the most abundant iron oxide in red mud, hematite, as possible carrier phase for Ce. Synthetic hematite can incorporate up to 1.70±0.01wt% Ce, which leads to a systematical increase of all unit cell parameters. Investigations by extended X-ray absorption fine structure spectroscopy suggest an incorporation of Ce 4+ O 6 into the hematite structure by a novel atomic arrangement, fundamentally different from the close-range order around Fe 3+ in hematite. Samples of red mud were taken in Lauta (Saxony), Germany and analyzed by powder X-ray diffraction, inductively coupled plasma mass and optical emission spectrometry, electron microprobe analysis and X-ray absorption near-edge structure spectroscopy. Red mud samples consist of hematite (Fe 2 O 3 ) (34-58wt%), sodalite (Na 8 Al 6 Si 6 O 24 Cl 2 ) (4-30wt%), gibbsite (Al(OH) 3 ) (0-25wt%), goethite (FeOOH) (10-23wt%), böhmite (AlOOH) (0-11wt%), rutile (TiO 2 ) (4-8wt%), cancrinite (Na 6 Ca 2 Al 6 Si 6 O 24 (CO 3 ) 2 ) (0-5wt%), nordstrandite (Al(OH) 3 ) (0-5wt%) and quartz (SiO 2 ) (0-4wt%). While the main elemental composition is Fe>Al>Na>Ti>Ca (Si not included), the average concentration of REE is 1109±6mg/kg with an average Ce concentration of 464±3mg/kg. The main carrier of Ce was located in the Fe-rich fine-grained fraction of red mud (0.10wt% Ce 2 O 3 ), while other potential Ce carriers like monazite, lead oxides, secondary Ce-minerals and particles of potentially anthropogenic origin are of subordinated relevance. Cerium in red mud occurs predominantly as Ce 4+ , which further excludes Ce 3+ minerals as relevant sources. Copyright © 2017. Published by Elsevier B.V.

Genes up-regulated during red coloration in UV-B irradiated lettuce leaves.

PubMed

Park, Jong-Sug; Choung, Myoung-Gun; Kim, Jung-Bong; Hahn, Bum-Soo; Kim, Jong-Bum; Bae, Shin-Chul; Roh, Kyung-Hee; Kim, Yong-Hwan; Cheon, Choong-Ill; Sung, Mi-Kyung; Cho, Kang-Jin

2007-04-01

Molecular analysis of gene expression differences between green and red lettuce leaves was performed using the SSH method. BlastX comparisons of subtractive expressed sequence tags (ESTs) indicated that 7.6% of clones encoded enzymes involved in secondary metabolism. Such clones had a particularly high abundance of flavonoid-metabolism proteins (6.5%). Following SSH, 566 clones were rescreened for differential gene expression using dot-blot hybridization. Of these, 53 were found to overexpressed during red coloration. The up-regulated expression of six genes was confirmed by Northern blot analyses. The expression of chalcone synthase (CHS), flavanone 3-hydroxylase (F3H), and dihydroflavonol 4-reductase (DFR) genes showed a positive correlation with anthocyanin accumulation in UV-B-irradiated lettuce leaves; flavonoid 3',5'-hydroxylase (F3',5'H) and anthocyanidin synthase (ANS) were expressed continuously in both samples. These results indicated that the genes CHS, F3H, and DFR coincided with increases in anthocyanin accumulation during the red coloration of lettuce leaves. This study show a relationship between red coloration and the expression of up-regulated genes in lettuce. The subtractive cDNA library and EST database described in this study represent a valuable resource for further research for secondary metabolism in the vegetable crops.

Pr:Ca1-xRxF2+x (R=Y or Gd) crystals: Modulated blue, orange and red emission spectra with the proportion of R3+ ions

NASA Astrophysics Data System (ADS)

Yu, Hao; Qian, Xiaobo; Guo, Linyang; Jiang, Dapeng; Wu, Qinghui; Tang, Fei; Su, Liangbi; Ju, Qiangwen; Wang, Jingya; Xu, Jun

2018-04-01

The spectroscopic properties of 0.6at.%:Pr:Ca1-xRxF2+x (R = Y, Gd; x = 0,0.006, 0.012, 0.03, 0.06) crystals were investigated and compared. The XRD tests were conducted and the cell dimensions of the crystals were calculated. Room temperature absorption spectra have been registered and analyzed. The emission spectra and decay curves of the crystals were obtained at room temperature. Increasing the proportion of the lattice regulators of Y3+ or Gd3+ ions could significantly enhance the luminescence intensity of all visible emission bands with different ratios. Particularly, the emission intensity ratio of orange to red increased from 0.15 to 1.9 in Pr:Ca1-xYxF2+x crystals and to 1.02 in Pr:Ca1-xGdxF2+x crystals, respectively. Furthermore, Pr:Ca1-xGdxF2+x crystals have substantially strong emission at orange and red region of 580-660 nm, comparable with blue light at 482 nm. The quantum efficiency of the crystals increased rapidly with the increment of R3+ concentration, and finally tend to be 100%.

Stabilization of the Ti{sub 3}Co{sub 5}B{sub 2}-type structure for Ti{sub 3−x}Si{sub x}Ru{sub 5}B{sub 2} through Si–Ti substitution

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

Xie, Weiwei, E-mail: weiweix@princeton.edu; Fuccillo, M.K.; Phelan, B.F.

2015-07-15

We report a route for designing and synthesizing Ti{sub 3}Co{sub 5}B{sub 2}-type compounds in the Ti–Ru–B system by using chemical substitution of Si for Ti to decrease the d-electron-based antibonding interactions that it is argued would otherwise drive an instability in this structure for unsubstituted Ti{sub 3}Ru{sub 5}B{sub 2}. Ti{sub 3−x}Si{sub x}Ru{sub 5}B{sub 2} with x=0.75, 1.00 and 1.25 nominal compositions crystalizes in the Ti{sub 3}Co{sub 5}B{sub 2} structure type using arc melting methods, whereas at lower doping levels (x=0.0, 0.25 and 0.50) the more complex Zn{sub 11}Rh{sub 18}B{sub 8}-type structure is stable. Electronic structure calculations show that in hypothetical,more » unsubstituted Ti{sub 3}Ru{sub 5}B{sub 2} with the Ti{sub 3}Co{sub 5}B{sub 2}-type structure, the antibonding interactions are strong around the Fermi level between the Ti and Ru in the structure that form tetragonal prisms. We propose that weakening these strong interactions through the partial substitution of isovalent Si for Ti leads to the observed stability of the Ti{sub 3}Co{sub 5}B{sub 2}-type structure for Ti{sub 3−x}Si{sub x}Ru{sub 5}B{sub 2} for x≈1. - Graphical abstract: We present the designing and synthesizing of Ti{sub 3}Co{sub 5}B{sub 2}-type compounds in the Ti–Ru–B system by using chemical substitution of Si for Ti to decrease the d-electron-based antibonding interactions that would otherwise drive an instability in this structure for unsubstituted Ti{sub 3}Ru{sub 5}B{sub 2}. Electronic structure calculations show that in hypothetical, unsubstituted Ti{sub 3}Ru{sub 5}B{sub 2} with the Ti{sub 3}Co{sub 5}B{sub 2}-type structure, the antibonding interactions are strong around the Fermi level between the Ti and Ru in the structure that form tetragonal prisms. We propose that weakening these strong interactions through the partial substitution of isovalent Si for Ti leads to the observed stability of the Ti{sub 3}Co{sub 5}B{sub 2}-type structure for

Ultrasound wave assisted adsorption of congo red using gold-magnetic nanocomposite loaded on activated carbon: Optimization of process parameters.

PubMed

Dil, Ebrahim Alipanahpour; Ghaedi, Mehrorang; Asfaram, Arash; Bazrafshan, Ali Akbar

2018-09-01

In this study, gold-magnetic nanocomposite in the presence of ultrasound wave assisted was synthesized and loaded on activated carbon (Au-Fe 3 O 4 -NCs-AC) by simple, fast and low-cost process. This novel material was applied for ultrasound assisted adsorption of congo red (CR) as model of toxic and even carcinogenic substance from aqueous solution. The detail of morphology and identity of Au-Fe 3 O 4 -AC was characterized by SEM and TEM techniques and correlation among response to variables such as pH (2-10), adsorbent mass (0.005-0.025 g), initial CR concentration (10-30 mg L -1 ) and ultrasound time (2-6 min) was investigated by response surface methodology (RSM) under central composite design (CCD). Analysis of variance (ANOVA) exhibit a high R 2 value of 0.999 and confirm suitability of constructed second-order regression model for excellent evaluation and prediction of the experimental data. The interaction and main factor and optimum conditions of the under study process were determined from response surface plots based on desirability function. The maximum CR adsorption were achieved at pH of 4, 15 mg L -1 of CR, 0.017 g of Au-Fe 3 O 4 -AC and 5 min sonication which owing to 99.49% removal efficiency is highly recommended for future CR removal from different matrixes. Adsorption kinetic follow second-order rate expression in combination to inter particle diffusion and equilibrium adsorption data best represented by the Langmuir isotherm with maximum mono-layer adsorption capacity of 43.88 mg g -1 . Copyright © 2018 Elsevier B.V. All rights reserved.

Study of Adsorption Mechanism of Congo Red on Graphene Oxide/PAMAM Nanocomposite

PubMed Central

Rafi, Mohammad; Samiey, Babak; Cheng, Chil-Hung

2018-01-01

Graphene oxide/poly(amidoamine) (GO/PAMAM) nanocomposite adsorbed high quantities of congo red (CR) anionic dye in 0.1 M NaCl solution, with the maximum adsorption capacity of 198 mg·g−1. The kinetics and thermodynamics of adsorption were investigated to elucidate the effects of pH, temperature, shaking rate, ionic strength, and contact time. Kinetic data were analyzed by the KASRA model and the KASRA, ISO, and pore-diffusion equations. Adsorption adsorption isotherms were studied by the ARIAN model and the Henry, Langmuir, and Temkin equations. It was shown that adsorption sites of GO/PAMAM at experimental conditions were phenolic hydroxyl groups of GO sheets and terminal amine groups of PAMAM dendrimer. Analysis of kinetic data indicated that amine sites were located on the surface, and that hydroxyl sites were placed in the pores of adsorbent. CR molecules interacted with the adsorption sites via hydrogen bonds. The molecules were adsorbed firstly on the amine sites, and then on the internal hydroxyl sites. Adsorption kinetic parameters indicated that the interaction of CR to the –NH3+ sites was the rate-controlling step of adsorption of CR on this site and adsorption activation energies calculated for different parts of this step. On the other hand, kinetic parameters showed that the intraparticle diffusion was the rate-controlling step during the interaction of CR molecules to –OH sites and activation energy of this step was not calculable. Finally, the used GO/PAMAM was completely regenerated by using ethylenediamine. PMID:29587463

Characterizing Congo Basin rainfall and climate using Tropical Rainfall Measuring Mission (TRMM) satellite data and limited rain gauge ground observations

USGS Publications Warehouse

Munzimi, Yolande A.; Hansen, Matthew C.; Adusei, Bernard; Senay, Gabriel B.

2015-01-01

Quantitative understanding of Congo River basin hydrological behavior is poor because of the basin’s limited hydrometeorological observation network. In cases such as the Congo basin where ground data are scarce, satellite-based estimates of rainfall, such as those from the joint NASA/JAXA Tropical Rainfall Measuring Mission (TRMM), can be used to quantify rainfall patterns. This study tests and reports the use of limited rainfall gauge data within the Democratic Republic of Congo (DRC) to recalibrate a TRMM science product (TRMM 3B42, version 6) in characterizing precipitation and climate in the Congo basin. Rainfall estimates from TRMM 3B42, version 6, are compared and adjusted using ground precipitation data from 12 DRC meteorological stations from 1998 to 2007. Adjustment is achieved on a monthly scale by using a regression-tree algorithm. The output is a new, basin-specific estimate of monthly and annual rainfall and climate types across the Congo basin. This new product and the latest version-7 TRMM 3B43 science product are validated by using an independent long-term dataset of historical isohyets. Standard errors of the estimate, root-mean-square errors, and regression coefficients r were slightly and uniformly better with the recalibration from this study when compared with the 3B43 product (mean monthly standard errors of 31 and 40 mm of precipitation and mean r2 of 0.85 and 0.82, respectively), but the 3B43 product was slightly better in terms of bias estimation (1.02 and 1.00). Despite reasonable doubts that have been expressed in studies of other tropical regions, within the Congo basin the TRMM science product (3B43) performed in a manner that is comparable to the performance of the recalibrated product that is described in this study.

Quantum chemical calculations of anion complex [B12Hx(CF3)12-x]2-, x = 9 - 12

NASA Astrophysics Data System (ADS)

Koblova, Elena A.; Saldin, Vitaly I.; Ustinov, Alexander Yu.

2016-12-01

The geometric, energetic, spectral and electronic properties of the most stable isomers of B12Hx(CF3)12-X2- anion complex with x = 9 - 12 have been studied using Density Functional Theory (B3LYP/6-311++G**). It was shown that these isomers are characterized by the preference to form the most symmetric structures with uniformly distributed charge densities. However, when replacing a hydrogen atom with fluoromethyl group, an inductive effect occurs. Blue shifts in the IR spectrum compared to the vibrations of the free CF3 molecule are in the range of 2 - 69 cm-1 and points to the stability of B12Hx(CF3)12-x2- anions.

Characterization of Terrestrial Water Dynamics in the Congo Basin Using GRACE and Satellite Radar Altimetry

NASA Technical Reports Server (NTRS)

Lee, Lyongki; Beighley, R. Edward; Alsdorf, Douglas; Jung, Hahn Chul; Shum, C. K.; Duan, Jianbin; Guo, Junyi; Yamazaki, Dai; Andreadis, Konstantinos

2011-01-01

The Congo Basin is the world's third largest in size (approximately 3.7 million km^2), and second only to the Amazon River in discharge (approximately 40,200 cms annual average). However, the hydrological dynamics of seasonally flooded wetlands and floodplains remains poorly quantified. Here, we separate the Congo wetland into four 3 degree x 3 degree regions, and use remote sensing measurements (i.e., GRACE, satellite radar altimeter, GPCP, JERS-1, SRTM, and MODIS) to estimate the amounts of water filling and draining from the Congo wetland, and to determine the source of the water. We find that the amount of water annually filling and draining the Congo wetlands is 111 km^3, which is about one-third the size of the water volumes found on the mainstem Amazon floodplain. Based on amplitude comparisons among the water volume changes and timing comparisons among their fluxes, we conclude that the local upland runoff is the main source of the Congo wetland water, not the fluvial process of river-floodplain water exchange as in the Amazon. Our hydraulic analysis using altimeter measurements also supports our conclusion by demonstrating that water surface elevations in the wetlands are consistently higher than the adjacent river water levels. Our research also highlights differences in the hydrology and hydrodynamics between the Congo wetland and the mainstem Amazon floodplain.

Swift adsorptive removal of Congo red from aqueous solution by K1.33Mn8O16 nanowires.

PubMed

Wu, Junshu; Li, Hongyi; Wang, Jinshu; Li, Zhifei

2013-08-01

A swift and efficient approach to converting organic dye effluents into fresh water could be of substantial benefit. In this study, we presented facile hydrothermal synthesis of K1.33Mn8O16 nanowires in ammonium fluoride (NH4F) aqueous solution. The crystallization process of K1.33Mn8O16 nanowires was investigated. The as-obtained K1.33Mn8O16 nanowires were used for swift adsorptive removal of Congo red from aqueous solution without adjusting pH value at room temperature. Adsorption kinetic experimental data are well described by pseudo-second-order rate kinetic model, and the adsorption isotherm fits Langmuir isotherm model. The present investigation provides an efficient approach to designing and fabricating manganese-based nanomaterials for environmental remediation.

Ca 1-xMo 1-ySi yO 4:Eu x3+: A novel red phosphor for white light emitting diodes

NASA Astrophysics Data System (ADS)

Ci, Zhipeng; Wang, Yuhua; Zhang, Jiachi; Sun, Yunkui

2008-03-01

Single phase of Ca 1-xMo 1-ySi yO 4:Eu x3+ (0.18⩽ x⩽0.26, 0⩽ y⩽0.04) was synthesized by solid-state method. The photoluminescence investigation indicated that Ca 1-xMoO 4:Eu x3+ (0.18⩽ x⩽0.26) could be effectively excited by 393 and 464 nm, and it exhibited an intense red emission at 615 nm. The introduction of Si 4+ ions did not change the position of the peaks but strongly enhanced the emission intensity of Eu 3+ under 393 and 464 nm excitations and showed very good color purity. The emission intensity of optimal Ca 0.8Mo 0.98Si 0.02O 4:Eu 0.23+ sample (excited by 393 nm) was about 5.5 times higher than that of the phosphor Y 2O 2S:0.05Eu 3+. So this phosphor could be nicely suitable for the application of the UV LED chips.

Pt@Ag and Pd@Ag core/shell nanoparticles for catalytic degradation of Congo red in aqueous solution.

PubMed

Salem, Mohamed A; Bakr, Eman A; El-Attar, Heba G

2018-01-05

Platinum/silver (Pt@Ag) and palladium/silver (Pd@Ag) core/shell NPs have been synthesized in two steps reaction using the citrate method. The progress of nanoparticle formation was followed by the UV/Vis spectroscopy. Transmission electron microscopy revealed spherical shaped core/shell nanoparticles with average particle diameter 32.17nm for Pt@Ag and 8.8nm for Pd@Ag. The core/shell NPs were further characterized by FT-IR and XRD. Reductive degradation of the Congo red dye was chosen to demonstrate the excellent catalytic activity of these core/shell nanostructures. The nanocatalysts act as electron mediators for the transfer of electrons from the reducing agent (NaBH 4 ) to the dye molecules. Effect of reaction parameters such as nanocatalyst dose, dye and NaBH 4 concentrations on the dye degradation was investigated. A comparison between the catalytic activities of both nanocatalysts was made to realize which of them the best in catalytic performance. Pd@Ag was the higher in catalytic activity over Pt@Ag. Such greater activity is originated from the smaller particle size and larger surface area. Pd@Ag nanocatalyst was catalytically stable through four subsequent reaction runs under the utilized reaction conditions. These findings can thus be considered as possible economical alternative for environmental safety against water pollution by dyes. Copyright © 2017. Published by Elsevier B.V.

Adsorptive amputation of hazardous azo dye Congo red from wastewater: a critical review.

PubMed

Raval, Nirav P; Shah, Prapti U; Shah, Nisha K

2016-08-01

Increasing amount of dyes in an ecosystem has propelled the search of various methods for dye removal. Amongst all the methods, adsorption occupies a prominent place in dye removal. Keeping this in mind, many adsorbents used for the removal of hazardous anionic azo dye Congo red (CR) from aqueous medium were reviewed by the authors. The main objectives behind this review article are to assemble the information on scattered adsorbents and enlighten the wide range of potentially effective adsorbents for CR removal. Thus, CR sorption by various adsorbents such as activated carbon, non-conventional low-cost materials, nanomaterials, composites and nanocomposites are surveyed and critically reviewed as well as their sorption capacities are also compared. This review also explores the grey areas of the adsorption performance of various adsorbents with reference to the effects of pH, contact time, initial dye concentration and adsorbent dosage. The equilibrium adsorption isotherm, kinetic and thermodynamic data of different adsorbents used for CR removal were also analysed. It is evident from a literature survey of more than 290 published papers that nanoparticle and nanocomposite adsorbents have demonstrated outstanding adsorption capabilities for CR. Graphical abstract ᅟ.

Photocatalytic degradation of organic dyes by Er3+: YAlO3/Co- and Fe-doped ZnO coated composites under solar irradiation

NASA Astrophysics Data System (ADS)

Chen, Yang; Lu, Chunxiao; Tang, Liang; Song, Yahui; Wei, Shengnan; Rong, Yang; Zhang, Zhaohong; Wang, Jun

2016-12-01

In this work, the Er3+: YAlO3/Co- and Fe-doped ZnO coated composites were prepared by the sol-gel method. Then, they were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). Photo-degradation of azo fuchsine (AF) as a model dye under solar light irradiation was studied to evaluate the photocatalytic activity of the Er3+: YAlO3/Co- and Fe-doped ZnO coated composites. It was found that the photocatalytic activity of Co- and Fe-doped ZnO composites can be obviously enhanced by upconversion luminescence agent (Er3+: YAlO3). Besides, the photocatalytic activity of Er3+: YAlO3/Fe-doped ZnO is better than that of Er3+: YAlO3/Co-doped ZnO. The influence of experiment conditions, such as the concentration of Er3+: YAlO3, heat-treatment temperature and time on the photocatalytic activity of the Er3+: YAlO3/Co- and Fe-doped ZnO coated composites was studied. In addition, the effects of solar light irradiation time, dye initial concentration, Er3+: YAlO3/Co- and Fe-doped ZnO amount on the photocatalytic degradation of azo fuchsine in aqueous solution were investigated in detail. Simultaneously, some other organic dyes, such as Methyl Orange (MO), Rhodamine B (RM-B), Acid Red B (AR-B), Congo Red (CR), and Methyl Blue (MB) were also studied. The possible excitation principle of Er3+: YAlO3/Co- and Fe-doped ZnO coated composites under solar light irradiation and the photocatalytic degradation mechanism of organic dyes were discussed.

Detoxification and color removal of Congo red by a novel Dietzia sp. (DTS26) - a microcosm approach.

PubMed

Satheesh Babu, S; Mohandass, C; Vijayaraj, A S; Dhale, Mohan A

2015-04-01

The present study deals with the decolorization and detoxification of Congo red (CR) by a novel marine bacterium Dietzia sp. (DTS26) isolated from Divar Island, Goa, India. The maximum decolorization of 94.5% (100 mg L(-1)) was observed under static condition within 30 h at pH 8 and temperature 32±2°C. Bacterially treated samples could enhance the light intensity by 38% and the primary production levels 5 times higher than the untreated. The strain was also able to reduce COD by 86.4% within 30 h at 100 mg L(-1) of CR dye. The degraded metabolites of CR dye were analyzed by FTIR, HPLC, GC-MS and the end product closely matches with 4-amino-3-naphthol-1-sulfonate which is comparatively less toxic than CR. Bioassay experiments conducted in treated samples for Artemia franciscana showed better survival rates (after 72 h) at higher concentration of CR (500 mg L(-1)). This work suggests the potential application of DTS26 in bioremediation of dye wastes and its safe disposal into coastal environment. Copyright © 2015 Elsevier Inc. All rights reserved.

Study of blood group B antigen with a specific monoclonal antibody (anti-B, b-183).

PubMed Central

Rouger, P; Edelman, L; Doinel, C; Reviron, J; Salmon, C; Bach, J F

1983-01-01

A murine anti-B monoclonal antibody was obtained by the hybridoma technique. This antibody called anti-B (b-183) is of IgM nature; it is capable of agglutinating normal B, B3, Bx, cis AB and some acquired B red cells. Its association constant is 1.1 X 10(8) l/mol, and appears high compared to those of the monoclonal anti-A. This monoclonal anti-B was used to determine the number of B sites on B3 and Bx red cells. PMID:6840810

Monomeric α-Synuclein Binds Congo Red Micelles in a Disordered Manner

PubMed Central

2011-01-01

The histological dye Congo Red (CR) previously has been shown to inhibit α-synuclein (aS) fibrillation, but the mode of this inhibition remained unclear. Because of favorable exchange kinetics, interaction between CR and aS lends itself to a detailed nuclear magnetic resonance study, and relaxation dispersion measurements yield the bound fraction and time scales for the interaction of aS with CR. We find that at pH 6, CR exists as a micelle, and at a CR:aS molar ratio of ∼1, only a small fraction of aS (∼2%) is bound to these micelles. Rapid exchange (kex ∼ 3000 s–1) between the free and CR-bound states broadens and strongly attenuates resonances of aS by two processes: a magnetic field-dependent contribution, caused by the chemical shift difference between the two states, and a nearly field-independent contribution caused by slower tumbling of aS bound to the CR micelle. The salt dependence of the interaction suggests a predominantly electrostatic mechanism for the 60 N-terminal residues, while the weaker interaction between residues 61–100 and CR is mostly hydrophobic. Chemical shift and transferred NOE data indicate that aS becomes slightly more helical but remains largely disordered when bound to CR. Results indicate that inhibition of fibril formation does not result from binding of CR to free aS and, therefore, must result from interaction of aS fibrils or protofibrils with CR micelles. PMID:22242826

Monomeric α-synuclein binds Congo Red micelles in a disordered manner.

PubMed

Maltsev, Alexander S; Grishaev, Alexander; Bax, Ad

2012-01-17

The histological dye Congo Red (CR) previously has been shown to inhibit α-synuclein (aS) fibrillation, but the mode of this inhibition remained unclear. Because of favorable exchange kinetics, interaction between CR and aS lends itself to a detailed nuclear magnetic resonance study, and relaxation dispersion measurements yield the bound fraction and time scales for the interaction of aS with CR. We find that at pH 6, CR exists as a micelle, and at a CR:aS molar ratio of ~1, only a small fraction of aS (~2%) is bound to these micelles. Rapid exchange (k(ex) ~ 3000 s(-1)) between the free and CR-bound states broadens and strongly attenuates resonances of aS by two processes: a magnetic field-dependent contribution, caused by the chemical shift difference between the two states, and a nearly field-independent contribution caused by slower tumbling of aS bound to the CR micelle. The salt dependence of the interaction suggests a predominantly electrostatic mechanism for the 60 N-terminal residues, while the weaker interaction between residues 61-100 and CR is mostly hydrophobic. Chemical shift and transferred NOE data indicate that aS becomes slightly more helical but remains largely disordered when bound to CR. Results indicate that inhibition of fibril formation does not result from binding of CR to free aS and, therefore, must result from interaction of aS fibrils or protofibrils with CR micelles.

Multicolor tuning towards single red-emission band of upconversion nanoparticles for tunable optical component and optical/x-ray imaging agents via Ce(3+) doping.

PubMed

Yi, Zhigao; Zeng, Tianmei; Xu, Yaru; Lu, Wei; Qian, Chao; Liu, Hongrong; Zeng, Songjun; Hao, Jianhua

2015-09-25

A simple strategy of Ce(3+) doping is proposed to realize multicolor tuning and predominant red emission in BaLnF5:Yb(3+)/Ho(3+) (Ln(3+) = Gd(3+), Y(3+), Yb(3+)) systems. A tunable upconversion (UC) multicolor output from green/yellow to red can be readily achieved in a fixed Yb(3+)/Ho(3+) composition by doping Ce(3+), providing an effective route for multicolor tuning widely used for various optical components. Moreover, compared with Ce(3+)-free UC nanoparticles (UCNPs), a remarkable enhancement of the red-to-green (R/G) ratio is observed by doping 30% Ce(3+), arising from the two largely promoted cross-relaxation (CR) processes between Ce(3+) and Ho(3+). UCNPs with pure red emission are selected as in vivo UC bioimaging agents, demonstrating the merits of deep penetration depth, the absence of autofluorescence and high contrast in small animal bioimaging. Moreover, such fluorescence imaging nanoprobes can also be used as contrast agents for three-dimensional (3D) x-ray bioimaging by taking advantage of the high K-edge values and x-ray absorption coefficients of Ba(2+), Gd(3+), and Ce(3+) in our designed nanoprobes. Thus, the simultaneous realization of multicolor output, highly enhanced R/G ratio, and predominant red emission makes the Ce(3+)-doped UCNPs very useful for widespread applications in optical components and bioimaging.

Amputation of congo red dye from waste water using microwave induced grafted Luffa cylindrica cellulosic fiber.

PubMed

Gupta, Vinod Kumar; Pathania, Deepak; Agarwal, Shilpi; Sharma, Shikha

2014-10-13

The present study deals with the surface modification of Luffa cylindrica fiber through graft copolymerization of methyl acrylate/acrylamide (MA/AAm) via microwave radiation without the use of initiator. Various reaction parameters effecting grafting yield were optimized and physico-chemical properties were evaluated. The grafted Luffa cylindrica fiber showed morphological transformations, thermal stability and chemical resistance. The adsorption potential of modified fiber was investigated using adsorption isotherms for hazardous congo red dye removal from aqueous system. The maximum adsorption capacity of dye onto grafted Luffa cylindrica fiber was found to be 17.39 mg/g with best fit for Langmuir adsorption isotherm. The values of thermodynamic parameters such as enthalpy change, ΔH(0) (21.27 kJ/mol), entropy change, ΔS(0) (64.71 J/mol K) and free energy change, ΔG(0) (-139.52 kJ/mol) were also calculated. Adsorption process was found spontaneous and endothermic in nature. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fabrication of hierarchical porous ZnO/NiO hollow microspheres for adsorptive removal of Congo red

NASA Astrophysics Data System (ADS)

Lei, Chunsheng; Pi, Meng; Cheng, Bei; Jiang, Chuanjia; Qin, Jiaqian

2018-03-01

Hierarchical porous zinc oxide (ZnO)/nickel(II) oxide (NiO) hollow microspheres were fabricated by a facile hydrothermal approach and subsequent calcination process. The synthesized samples were used as adsorbent for removing Congo red (CR), a commercial azo dye. The synthesized hierarchical porous ZnO/NiO composites exhibit a superior adsorption capacity for CR (518 mg/g), compared with pure NiO (397 mg/g) and ZnO (304 mg/g). The high CR adsorption capacity of ZnO/NiO composites was associated with its hierarchical porous hollow structures and large specific surface area (130 m2/g), which provide a large quantity of active sites for CR molecules. The adsorption kinetics data were perfectly fitted to a pseudo-second-order model. The isotherms were accurately described by the Langmuir model. The results suggest that the as-prepared hierarchical porous ZnO/NiO composites are a highly efficient adsorbent for treating organic dye-impacted wastewater.

21 CFR 74.1303 - FD&C Red No. 3.

Code of Federal Regulations, 2010 CFR

2010-04-01

... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1303 FD&C Red No. 3. (a) Identity and specifications. (1) The color additive FD&C Red No. 3 shall conform in identity and specifications to the requirements of § 74.303(a)(1) and (b). (2) Color additive mixtures for ingested drug used made with FD&C Red No. 3 may...

21 CFR 74.1303 - FD&C Red No. 3.

Code of Federal Regulations, 2014 CFR

2014-04-01

... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1303 FD&C Red No. 3. (a) Identity and specifications. (1) The color additive FD&C Red No. 3 shall conform in identity and specifications to the requirements of § 74.303(a)(1) and (b). (2) Color additive mixtures for ingested drug used made with FD&C Red No. 3 may...

21 CFR 74.1303 - FD&C Red No. 3.

Code of Federal Regulations, 2013 CFR

2013-04-01

... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1303 FD&C Red No. 3. (a) Identity and specifications. (1) The color additive FD&C Red No. 3 shall conform in identity and specifications to the requirements of § 74.303(a)(1) and (b). (2) Color additive mixtures for ingested drug used made with FD&C Red No. 3 may...

21 CFR 74.1303 - FD&C Red No. 3.

Code of Federal Regulations, 2012 CFR

2012-04-01

... ADDITIVES SUBJECT TO CERTIFICATION Drugs § 74.1303 FD&C Red No. 3. (a) Identity and specifications. (1) The color additive FD&C Red No. 3 shall conform in identity and specifications to the requirements of § 74.303(a)(1) and (b). (2) Color additive mixtures for ingested drug used made with FD&C Red No. 3 may...

78 FR 16028 - Waiver of Restriction on Assistance to the Central Government of the Democratic Republic of Congo

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-13

... DEPARTMENT OF STATE [Public Notice 8231] Waiver of Restriction on Assistance to the Central Government of the Democratic Republic of Congo Pursuant to Section 7031(b)(3) of the Department of State... the Act with respect to the Democratic Republic of Congo and I hereby waive this restriction. This...

Enhanced adsorption of congo red from aqueous solutions by chitosan hydrogel beads impregnated with cetyl trimethyl ammonium bromide.

PubMed

Chatterjee, Sudipta; Lee, Dae S; Lee, Min W; Woo, Seung H

2009-06-01

The adsorption of congo red (CR) onto chitosan (CS) beads impregnated by a cationic surfactant (CTAB, cetyl trimethyl ammonium bromide) was investigated. Chitosan beads impregnated at a ratio of 1/20 of CTAB to CS (0.05% of CTAB and 1% of CS) increased the CR adsorption capacity by 2.2 times from 162.3 mg/g (0% CTAB) to 352.5 mg/g (0.05% CTAB). The CR adsorption decreased with an increase in pH of the CR solution from 4.0 to 9.0. The Sips isotherm model showed a good fit with the equilibrium experimental data and the values of the heterogeneity factor (n) indicated heterogeneous adsorption of CR onto CS/CTAB beads, as well as CS beads. The kinetic data showed better fit to the pseudo second-order rate model than to the pseudo first-order rate model. The impregnation of CS beads by cationic surfactants showed the highest adsorption capacities of CR compared to any other adsorbents and would be a good method to increase adsorption efficiency for the removal of anionic dyes in a wastewater treatment process.

Removal of Congo Red and Methylene Blue from Aqueous Solutions by Vermicompost-Derived Biochars

PubMed Central

Yang, Gang; Wu, Lin; Xian, Qiming; Shen, Fei; Wu, Jun; Zhang, Yanzong

2016-01-01

Biochars, produced by pyrolyzing vermicompost at 300, 500, and 700°C were characterized and their ability to adsorb the dyes Congo red (CR) and Methylene blue (MB) in an aqueous solution was investigated. The physical and chemical properties of biochars varied significantly based on the pyrolysis temperatures. Analysis of the data revealed that the aromaticity, polarity, specific surface area, pH, and ash content of the biochars increased gradually with the increase in pyrolysis temperature, while the cation exchange capacity, and carbon, hydrogen, nitrogen and oxygen contents decreased. The adsorption kinetics of CR and MB were described by pseudo-second-order kinetic models. Both of Langmuir and Temkin model could be employed to describe the adsorption behaviors of CR and MB by these biochars. The biochars generated at higher pyrolysis temperature displayed higher CR adsorption capacities and lower MB adsorption capacities than those compared with the biochars generated at lower pyrolysis temperatures. The biochar generated at the higher pyrolytic temperature displayed the higher ability to adsorb CR owing to its promoted aromaticity, and the cation exchange is the key factor that positively affects adsorption of MB. PMID:27144922

Removal of Congo Red and Methylene Blue from Aqueous Solutions by Vermicompost-Derived Biochars.

PubMed

Yang, Gang; Wu, Lin; Xian, Qiming; Shen, Fei; Wu, Jun; Zhang, Yanzong

2016-01-01

Biochars, produced by pyrolyzing vermicompost at 300, 500, and 700°C were characterized and their ability to adsorb the dyes Congo red (CR) and Methylene blue (MB) in an aqueous solution was investigated. The physical and chemical properties of biochars varied significantly based on the pyrolysis temperatures. Analysis of the data revealed that the aromaticity, polarity, specific surface area, pH, and ash content of the biochars increased gradually with the increase in pyrolysis temperature, while the cation exchange capacity, and carbon, hydrogen, nitrogen and oxygen contents decreased. The adsorption kinetics of CR and MB were described by pseudo-second-order kinetic models. Both of Langmuir and Temkin model could be employed to describe the adsorption behaviors of CR and MB by these biochars. The biochars generated at higher pyrolysis temperature displayed higher CR adsorption capacities and lower MB adsorption capacities than those compared with the biochars generated at lower pyrolysis temperatures. The biochar generated at the higher pyrolytic temperature displayed the higher ability to adsorb CR owing to its promoted aromaticity, and the cation exchange is the key factor that positively affects adsorption of MB.

78 FR 76699 - Waiver of Restriction on Assistance to the Central Government of the Republic of the Congo

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-18

... DEPARTMENT OF STATE [Public Notice 8551] Waiver of Restriction on Assistance to the Central Government of the Republic of the Congo Pursuant to Section 7031(b)(3) of the Department of State, Foreign... prior year Acts with respect to the Republic of the Congo and I hereby waive this restriction. This...

Two Red Clumps and the X-shaped Milky Way Bulge

NASA Astrophysics Data System (ADS)

McWilliam, Andrew; Zoccali, Manuela

2010-12-01

From Two Micron All Sky Survey infrared photometry, we find two red clump (RC) populations coexisting in fields toward the Galactic bulge at latitudes |b|>5fdg5, ranging over ~13° in longitude and 20° in latitude. These RC peaks indicate two stellar populations separated by ~2.3 kpc at (l, b) = (+1, - 8) the two RCs are located at 6.5 and 8.8 ± 0.2 kpc. The double-peaked RC is inconsistent with a tilted bar morphology. Most of our fields show the two RCs at roughly constant distance with longitude, also inconsistent with a tilted bar; however, an underlying bar may be present. Stellar densities in the two RCs change dramatically with longitude: on the positive longitude side the foreground RC is dominant, while the background RC dominates negative longitudes. A line connecting the maxima of the foreground and background populations is tilted to the line of sight by ~20°±4°, similar to claims for the tilt of a Galactic bar. The distance between the two RCs decreases toward the Galactic plane; seen edge-on the bulge is X-shaped, resembling some extragalactic bulges and the results of N-body simulations. The center of this X is consistent with the distance to the Galactic center, although better agreement would occur if the bulge is 2-3 Gyr younger than 47 Tuc. Our observations may be understood if the two RC populations emanate, nearly tangentially, from the Galactic bar ends, in a funnel shape. Alternatively, the X, or double funnel, may continue to the Galactic center. From the Sun, this would appear peanut/box shaped, but X-shaped when viewed tangentially.

Deletion of admB gene encoding a fungal ADAM affects cell wall construction in Aspergillus oryzae.

PubMed

Kobayashi, Takuji; Maeda, Hiroshi; Takeuchi, Michio; Yamagata, Youhei

2017-05-01

Mammals possess a unique signaling system based on the proteolytic mechanism of a disintegrin and metalloproteinases (ADAMs) on the cell surface. We found two genes encoding ADAMs in Aspergillus oryzae and named them admA and admB. We produced admA and admB deletion strains to elucidate their biological function and clarify whether fungal ADAMs play a similar role as in mammals. The ∆admA∆admB and ∆admB strains were sensitive to cell wall-perturbing agents, congo red, and calcofluor white. Moreover, the two strains showed significantly increased weights of total alkali-soluble fractions from the mycelial cell wall compared to the control strain. Furthermore, ∆admB showed MpkA phosphorylation at lower concentration of congo red stimulation than the control strain. However, the MpkA phosphorylation level was not different between ∆admB and the control strain without the stimulation. The results indicated that A. oryzae AdmB involved in the cell wall integrity without going through the MpkA pathway.

Investigation on the Room-temperature preparation of Cobalt hybrid/Graphene Nanocomposite and application in wastewater purification: Highly Efficient Removal of Congo Red

NASA Astrophysics Data System (ADS)

Wang, L. X.; Zhao, Y. F.; Meng, Q. M.

2018-01-01

Here, we are going to report a simple, low-cost and environmental friendly process to prepare the cobalt hybrid/graphene (Co/G) nanocomposite at room temperature. NaBH4 was used as the reducing agent. Such an approach can be extended to grow some other metal/G nanocomposites, for example, Ni/G, Co/G nanocomposite possesses narrow size-distribution and good dispersion. Because of the special appearance with large surface area, and the special synthesis process of the productions, adsorption experiments for Congo Red were carried out in synthetic wastewater. The CR removal ability of Co/G nanocomposite can reach 263.2 mg/g.

Decolorization and biodegradation of the Congo red by Acinetobacter baumannii YNWH 226 and its polymer production's flocculation and dewatering potential.

PubMed

Li, Ruijing; Ning, Xun-an; Sun, Jian; Wang, Yujie; Liang, Jieying; Lin, Meiqing; Zhang, Yaping

2015-10-01

The strain Acinetobacter baumannii YNWH 226 was utilized to degrade Congo red (CR) under aerobic conditions. CR was employed as the sole carbon source to produce extracellular polymeric substances (EPS) used as potent bioflocculants in this strain. A total of 98.62% CR was removed during the 48-h decoloration experiments using CR (100 mg/L). A total of 83% bioadsorption and 65% biodegradation were responsible for the decoloration and degradation of CR through the strain. The bioflocculant showed high flocculation activity and dewaterability on textile dyeing sludge. A maximum flocculation of 78.62% with a minimum SBF of 3.07×10(9) s(2)/g and a CST of 58.4 s were achieved. We investigated the internal relationship between the decolorization efficiency of YNWH 226 and the flocculation activity and dewatering capacity of its EPS. The components and structure of the EPS highly influenced the decolorization efficiency of CR and the flocculation activity and dewatering capacity on sludge. Copyright © 2015 Elsevier Ltd. All rights reserved.

Instability of monoclonal myeloma protein may be identified as susceptibility to penetration and binding by newly synthesized Congo red derivatives.

PubMed

Spólnik, Paweł; Konieczny, Leszek; Piekarska, Barbara; Rybarska, Janina; Stopa, Barbara; Zemanek, Grzegorz; Król, Marcin; Roterman, Irena

2004-06-01

Monoclonal myeloma proteins often have an abnormal, unstable structure, and tend to aggregate with fatal clinical consequences. A method for early clinical identification of this aggregation tendency is impatiently awaited. This work proposes the use of supramolecular dyes as specific ligands to reveal protein instability. Disclosure of excessive polypeptide chain flexibility in unstable monoclonal proteins, leading to increased susceptibility to penetration by foreign compounds, appeared possible when new supramolecular Congo red-derived dyes with different protein-binding capabilities were used for complexation. Two basic protein instability levels, local and global, were differentiated by comparing the extent of protein loading with dye and the subsequent electrophoretic migration rate of the complexes. A simple electrophoretic test is proposed for assessment of the instability of monoclonal proteins in clinical conditions.

Diversity, Replication, Pathogenicity and Cell Biology of Crimean Congo Hemorrhagic Fever Virus

DTIC Science & Technology

2007-10-01

Crimean Congo Hemorrhagic Fever Virus PRINCIPAL INVESTIGATOR: Adolfo García-Sastre, Ph.D. CONTRACTING...Diversity, Replication, Pathogenicity and Cell Biology of Crimean Congo Hemorrhagic Fever Virus 5b. GRANT NUMBER W81XWH-04-1-0876 5c. PROGRAM ELEMENT...localization and antigenic characterization of Crimean - Congo hemorrhagic fever virus glycoproteins. J.Virol. 79: 6152-61. Ahmed, A., McFalls,

Autochthonous Crimean-Congo Hemorrhagic Fever in Spain.

PubMed

Negredo, Anabel; de la Calle-Prieto, Fernando; Palencia-Herrejón, Eduardo; Mora-Rillo, Marta; Astray-Mochales, Jenaro; Sánchez-Seco, María P; Bermejo Lopez, Esther; Menárguez, Javier; Fernández-Cruz, Ana; Sánchez-Artola, Beatriz; Keough-Delgado, Elena; Ramírez de Arellano, Eva; Lasala, Fátima; Milla, Jakob; Fraile, Jose L; Ordobás Gavín, Maria; Martinez de la Gándara, Amalia; López Perez, Lorenzo; Diaz-Diaz, Domingo; López-García, M Aurora; Delgado-Jimenez, Pilar; Martín-Quirós, Alejandro; Trigo, Elena; Figueira, Juan C; Manzanares, Jesús; Rodriguez-Baena, Elena; Garcia-Comas, Luis; Rodríguez-Fraga, Olaia; García-Arenzana, Nicolás; Fernández-Díaz, Maria V; Cornejo, Victor M; Emmerich, Petra; Schmidt-Chanasit, Jonas; Arribas, Jose R

2017-07-13

Crimean-Congo hemorrhagic fever (CCHF) is a widely distributed, viral, tickborne disease. In Europe, cases have been reported only in the southeastern part of the continent. We report two autochthonous cases in Spain. The index patient acquired the disease through a tick bite in the province of Ávila - 300 km away from the province of Cáceres, where viral RNA from ticks was amplified in 2010. The second patient was a nurse who became infected while caring for the index patient. Both were infected with the African 3 lineage of this virus. (Funded by Red de Investigación Cooperativa en Enfermedades Tropicales [RICET] and Efficient Response to Highly Dangerous and Emerging Pathogens at EU [European Union] Level [EMERGE].).

Nanotheranostics: Congo Red/Rutin-MNPs with Enhanced Magnetic Resonance Imaging and H2O2-Responsive Therapy of Alzheimer's Disease in APPswe/PS1dE9 Transgenic Mice.

PubMed

Hu, Bingbing; Dai, Fengying; Fan, Zhanming; Ma, Guanghui; Tang, Qunwei; Zhang, Xin

2015-10-07

As nanotheranostics, Congo red/Rutin-MNPs combine the abilities of diagnosis and treatment of Alzheimer's disease (AD). The biocompatible nanotheranostics system based on iron oxide magnetic nanoparticles, with ultrasmall size and excellent magnetic properties, can specifically detect amyloid plaques by magnetic resonance imaging, realize targeted delivery of AD therapeutic agents, achieve drug controlled release by H2O2 response, and prevent oxidative stress. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chlorine dioxide-induced and Congo red-inhibited Marangoni effect on the chlorite-trithionate reaction front

NASA Astrophysics Data System (ADS)

Liu, Yang; Ren, Xingfeng; Pan, Changwei; Zheng, Ting; Yuan, Ling; Zheng, Juhua; Gao, Qingyu

2017-10-01

Hydrodynamic flows can exert multiple effects on an exothermal autocatalytic reaction, such as buoyancy and the Marangoni convection, which can change the structure and velocity of chemical waves. Here we report that in the chlorite-trithionate reaction, the production and consumption of chlorine dioxide can induce and inhibit Marangoni flow, respectively, leading to different chemo-hydrodynamic patterns. The horizontal propagation of a reaction-diffusion-convection front was investigated with the upper surface open to the air. The Marangoni convection, induced by gaseous chlorine dioxide on the surface, produced from chlorite disproportionation after the proton autocatalysis, has the same effect as the heat convection. When the Marangoni effect is removed by the reaction of chlorine dioxide with the Congo red (CR) indicator, an oscillatory propagation of the front tip is observed under suitable conditions. Replacing CR with bromophenol blue (BPB) distinctly enhanced the floating, resulting in multiple vortexes, owing to the coexistence between BPB and chlorine dioxide. Using the incompressible Navier-Stokes equations coupled with reaction-diffusion and heat conduction equations, we numerically obtain various experimental scenarios of front instability for the exothermic autocatalytic reaction coupled with buoyancy-driven convection and Marangoni convection.

Enhanced efficiency of luminescence with stoichiometry control in LiGd(W(1-x)MoxO4)2:Eu3+ red phosphors

NASA Astrophysics Data System (ADS)

Kavi Rasu, K.; Balaji, D.; Moorthy Babu, S.

2017-06-01

A series of LiGd(W(1-x)MoxO4)2 [hereafter LGWM]:Eu3+(x=0.00 to 1.00) red-emitting phosphors were synthesized by sol-gel method. Metal nitrates were used as starting materials with citric acid as chelator and ethylene glycol as binder. Synthesized gel was pre-fired at 523 K and calcined at 1073 K using resistive furnace in air atmosphere. The crystallinity, surface morphology and luminescent properties of the phosphors were investigated using powder X-ray diffraction (XRD), scanning electron microscope (SEM) and fluorescence spectrophotometry respectively. The intensity of the red emission at 615 nm for 5D0→7F2 electric dipole transition increases as the content of Mo6+ was increased and reach a maximum, when the relative ratio of W/Mo is 1:1 under 396 nm excitation.

Combined thioflavin T-Congo red fluorescence assay for amyloid fibril detection

NASA Astrophysics Data System (ADS)

Girych, Mykhailo; Gorbenko, Galyna; Maliyov, Ivan; Trusova, Valeriya; Mizuguchi, Chiharu; Saito, Hiroyuki; Kinnunen, Paavo

2016-09-01

Fluorescence represents one of the most powerful tools for the detection and structural characterization of the pathogenic protein aggregates, amyloid fibrils. The traditional approaches to the identification and quantification of amyloid fibrils are based on monitoring the fluorescence changes of the benzothiazole dye thioflavin T (ThT) and absorbance changes of the azo dye Congo red (CR). In routine screening it is usually sufficient to perform only the ThT and CR assays, but both of them, when used separately, could give false results. Moreover, fibrillization kinetics can be measured only by ThT fluorescence, while the characteristic absorption spectra and birefringence of CR represent more rigid criteria for the presence of amyloid fibrils. Therefore, it seemed reasonable to use both these dyes simultaneously, combining the advantages of each technique. To this end, we undertook a detailed analysis of the fluorescence spectral behavior of these unique amyloid tracers upon their binding to amyloid fibrils from lysozyme, insulin and an N-terminal fragment of apolipoprotein A-I with Iowa mutation. The fluorescence measurements revealed several criteria for distinguishing between fibrillar and monomeric protein states: (i) a common drastic increase in ThT fluorescence intensity; (ii) a sharp decrease in ThT fluorescence upon addition of CR; (iii) an appearance of the maximum at 535-540 nm in the CR excitation spectra; (iv) increase in CR fluorescence intensity at 610 nm. Based on these findings we designed a novel combined ThT-CR fluorescence assay for amyloid identification. Such an approach not only strengthens the reliability of the ThT assay, but also provides new opportunities for structural characterization of amyloid fibrils.

A new five-coordinated copper compound for efficient degradation of methyl orange and Congo red in the absence of UV-visible radiation.

PubMed

Han, Li-Juan; Kong, Ya-Jie; Yan, Ting-Jiang; Fan, Lu-Tong; Zhang, Qi; Zhao, Hua-Jun; Zheng, He-Gen

2016-11-22

A new copper-based coordination compound Cu 2 (2,2'-bipy) 2 (pfbz) 4 (1) (where 2,2'-bipy = 2,2'-bipyridine; pfbz = pentafluorobenzoate), was hydrothermally synthesized and structurally characterized. Compound 1 having a binuclear structure consists of two copper cations and two oxygen atoms alternately in a plane square arrangement. In the presence of very small amounts of H 2 O 2 , the catalytic properties of compound 1 for the degradation of methyl orange (MO) are excellent in the absence of UV-visible radiation. Moreover, compound 1 presents suitable properties for degradation of Congo red (CR). Our results indicated that the five-coordinated copper compound, 1, will be a promising candidate for efficient degradation of organic dyes.

Novel red phosphors KBaEu(XO4)3 (X = Mo, W) show high color purity and high thermostability from a disordered chained structure.

PubMed

Wang, G Q; Gong, X H; Chen, Y J; Huang, J H; Lin, Y F; Luo, Z D; Huang, Y D

2017-05-23

Two novel red phosphors KBaEu(XO 4 ) 3 (X = Mo, W) have been synthesized by high-temperature solid-state reactions and the crystal structures were determined for the first time. Single-crystal X-ray diffraction data reveal that their space groups are C2/c. The crystalline structure is constituted of K/BaO 8 distorted square antiprisms and distorted EuO 8 polyhedra which form chains lying along the c-axis and two kinds of distorted XO 4 tetrahedra. This high disorder of K/Ba which might lower the crystal field symmetry around Eu 3+ results in the high purity of red emission around 615 nm originating from 5 D 0 → 7 F 2 transition under near-ultraviolet (NUV) excitation. With increasing temperature, the luminescence of KBaEu(XO 4 ) 3 (X = Mo, W) phosphors decreases almost linearly with subtle alteration for the CIE coordinate. As the temperature reaches 550 K, the red emission intensity decreases to 37.3% and 50.7% of that at 300 K for KBaEu(MoO 4 ) 3 and KBaEu(WO 4 ) 3 , respectively. The analysis of the decay curves of the 5 D 0 → 7 F 2 emission at variable temperatures indicates the weak cross relaxation and non-radiative energy transfer between Eu 3+ ions. These results demonstrate that the investigated phosphors are attractive for application in high power NUV excited white LEDs.

Effects of Sm3+ on Luminescent Properties of LiEu(0.55-x)Y0.45 (WO4)2Smx Red Phosphor

NASA Astrophysics Data System (ADS)

Zailani, N. S.; Ghazli, M. F.; Hussin, R.; Rahim, S. Z. Abd; Mat Saad, M. N.

2018-06-01

Phosphor materials have been widely applied in lighting and displays. Rare earth elements are amongst important elements in giving luminescent properties to the phosphor. The needs to reduce rare earth element in phosphor is of interest due to cost and environmental issue. The red phosphor LiEu(0.55-x)Y0.45(WO4)2 were synthesized by substituting Sm3+ in the lattice using solid-state reaction. The effect on the substitution of Sm3+ which acts as an activator will be analysed using X-ray powder diffraction (XRPD), scanning electron microscope (SEM) and photoluminescence spectra (PL). The structure of the compound was found to be as a monoclinic which referred to the reference patterns. The optimum amount was recorded for the activator to be obtained in the host lattice for replacing the Eu3+ place as well as enhancing the intensity of the emission. The findings reveal that LiEu(0.55-x)Y0.45(MoO4)2Smx can be a more efficient red phosphor candidate used white light emitting diodes (WLEDs) applications.

Description of two new Bathyaethiops species (Teleostei: Alestidae) from the Congo basin.

PubMed

Moritz, Timo; Schliewen, Ulrich K

2016-06-02

Two new species of Bathyaethiops (Teleostei: Characiformes: Alestidae) are described. Bathyaethiops baka n. sp. is a dwarf species with the largest known specimen being only 24.4 mm SL. The species is characterized by an incomplete squamation and a large humeral spot. Bathyaethiops baka n. sp. is known so far only from the Ngoko River of Southeastern Cameroon, a tributary of the Sangha River in the northern Congo basin. The second species, Bathyaethiops flammeus n. sp., shows a diagnostic spot in front of the dorsal-fin base, which is devoid of melanophores and bright red in life. The species is described from the Bakéré River at Yambula-Bakéré, a locality north-west of Kisangani in the Central Congo basin. Other records of Bathyaethiops flammeus n. sp. from the Tshuapa respectively Ruki River at Boende and Eala, Central Congo basin, suggests a wider geographic distribution. A key to all species of Bathyaethiops is provided.

Photoluminescence of A- and B-site Eu{sup 3+}-substituted (Sr{sub x}Ba{sub 1−x}){sub 2}CaW{sub y}Mo{sub 1−y}O{sub 6} phosphors

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

Sletnes, M.; Lindgren, M.; Valmalette, J.C.

The photoluminescence of two series of A- and B-site Eu{sup 3+} substituted (Sr{sub x}Ba{sub 1−x}){sub 2}CaW{sub y}Mo{sub 1−y}O{sub 6} double perovskite phosphor materials, (Sr{sub x}Ba{sub 1−x}){sub 1.96}Eu{sub 0.02}K{sub 0.02}CaW{sub y}Mo{sub 1−y}O{sub 6} and (Sr{sub x}Ba{sub 1−x}){sub 2}Ca{sub 0.96}Eu{sub 0.02}Li{sub 0.02}W{sub y}Mo{sub 1−y}O{sub 6} (x and y=0, 0.25, 0.50, 0.75, and 1), were studied systematically as a function of stoichiometry and crystal structure. The Eu{sup 3+} lattice sites controlled by co-doping with either K or Li were confirmed by Raman spectroscopy. The variation in integrated emission intensity and emission colour over the experimental matrix was examined using statistical tools, and themore » observed trends were rationalized based on the physical and electronic structure of the phosphors. Phosphors with Eu on B-site with maximum Sr content had remarkably higher emission intensities than all other materials, but the emission was more orange than red due to domination of the {sup 5}D{sub 0}–{sup 7}F{sub 1} (595 nm) transition of Eu{sup 3+}. The relative intensities of the {sup 5}D{sub 0}–{sup 7}F{sub 2} (615 nm) and {sup 5}D{sub 0}–{sup 7}F{sub 1} transitions of Eu{sup 3+}, and thus the red-shift of the emission, decreased linearly with increasing Sr content in the A-site Eu-substituted phosphors, and reached a maximum for Sr{sub 1.96}Eu{sub 0.02}K{sub 0.02}CaW{sub 0.25}Mo{sub 0.75}O{sub 6}. A maximum external quantum efficiency of 17% was obtained for the phosphor Sr{sub 2}Ca{sub 0.7}Eu{sub 0.15}Li{sub 0.15}W{sub 0.5}Mo{sub 0.5}O{sub 6} with Eu on B-site. - Highlights: • Systematic study of the photoluminescence of Eu{sup 3+}-doped (Sr{sub x}Ba{sub 1−x}){sub 2}CaW{sub y}Mo{sub 1−y}O{sub 6}. • The Eu{sup 3+} lattice sites were confirmed by Raman spectroscopy. • A large parameter space was investigated using statistical tools. • A maximum external QE of 17% was obtained for Sr{sub 2}Ca{sub 0.7}Eu{sub 0

Negative hyperconjugation and red-, blue- or zero-shift in X-Z∙∙∙Y complexes.

PubMed

Joy, Jyothish; Jemmis, Eluvathingal D; Vidya, Kaipanchery

2015-01-01

A generalized explanation is provided for the existence of the red- and blue-shifting nature of X-Z bonds (Z=H, halogens, chalcogens, pnicogens, etc.) in X-Z∙∙∙Y complexes based on computational studies on a selected set of weakly bonded complexes and analysis of existing literature data. The additional electrons and orbitals available on Z in comparison to H make for dramatic differences between the H-bond and the rest of the Z-bonds. The nature of the X-group and its influence on the X-Z bond length in the parent X-Z molecule largely controls the change in the X-Z bond length on X-Z∙∙∙Y bond formation; the Y-group usually influences only the magnitude of the effects controlled by X. The major factors which control the X-Z bond length change are: (a) negative hyperconjugative donation of electron density from X-group to X-Z σ* antibonding molecular orbital (ABMO) in the parent X-Z, (b) induced negative hyperconjugation from the lone pair of electrons on Z to the antibonding orbitals of the X-group, and (c) charge transfer (CT) from the Y-group to the X-Z σ* orbital. The exchange repulsion from the Y-group that shifts partial electron density at the X-Z σ* ABMO back to X leads to blue-shifting and the CT from the Y-group to the σ* ABMO of X-Z leads to red-shifting. The balance between these two opposing forces decides red-, zero- or blue-shifting. A continuum of behaviour of X-Z bond length variation is inevitable in X-Z∙∙∙Y complexes.

Effective removal of Congo red dye from aqueous solution using modified xanthan gum/silica hybrid nanocomposite as adsorbent.

PubMed

Ghorai, Soumitra; Sarkar, Amit Kumar; Panda, A B; Pal, Sagar

2013-09-01

The aim of this work is to study the feasibility of XG-g-PAM/SiO2 nanocomposite towards its potential application as high performance adsorbent for removal of Congo red (CR) dye from aqueous solution. The surface area, average pore size and total pore volume of the developed nanocomposite has been determined. The efficiency of CR dye adsorption depends on various factors like pH, temperature of the solution, equilibrium time of adsorption, agitation speed, initial concentration of dye and adsorbent dosage. It has been observed that the nanocomposite is having excellent CR dye adsorption capacity (Q0=209.205 mg g(-1)), which is considerably high. The dye adsorption process is controlled by pseudo-second order and intraparticle diffusion kinetic models. The adsorption equilibrium data correlates well with Langmuir isotherm. Desorption study indicates the efficient regeneration ability of the dye loaded nanocomposite. Copyright © 2013 Elsevier Ltd. All rights reserved.

Synthesis of 3D iron and carbon-based composite as a bifunctional sorbent and catalyst for remediation of organic pollutants

NASA Astrophysics Data System (ADS)

Li, Ling; Shen, Yi; Wang, Zhaomei

2017-07-01

We prepared a 3D monolith by integrating graphite nanosheet encapsulated iron nanoparticles (Fe@GNS) into graphite felt (GF) supports. The structural properties of the resulting Fe@GNS/GF monolith are characterized by x-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy and N2 adsorption-desorption isotherms. The Fe@GNS/GF monoliths are utilized as a bifunctional sorbent and catalyst for water remediation. Using Congo red and methyl violet 2B as model pollutants, the sorption and catalytic performance of the Fe@GNS/GF composite are examined. The Fe@GNS/GF monolith possesses maximum sorption capacities of 177 and 142 mg g-1 for the sorption of CR and MV-2B, respectively. It also exhibits rate constants of 0.0563 and 0.0464 min-1 for the catalytic degradation of CR and MV-2B, respectively. As a proof of concept, the Fe@GNS/GF is successfully utilized to decontaminate simulated organic waste water via a combination of sorption and catalytic degradation processes.

21 CFR 74.1303 - FD&C Red No. 3.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 1 2011-04-01 2011-04-01 false FD&C Red No. 3. 74.1303 Section 74.1303 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR... use in color additive mixtures for coloring ingested drugs. (b) Uses and restrictions. FD&C Red No. 3...

The X-CLASS-redMaPPer galaxy cluster comparison. I. Identification procedures

NASA Astrophysics Data System (ADS)

Sadibekova, T.; Pierre, M.; Clerc, N.; Faccioli, L.; Gastaud, R.; Le Fevre, J.-P.; Rozo, E.; Rykoff, E.

2014-11-01

Context. This paper is the first in a series undertaking a comprehensive correlation analysis between optically selected and X-ray-selected cluster catalogues. The rationale of the project is to develop a holistic picture of galaxy clusters utilising optical and X-ray-cluster-selected catalogues with well-understood selection functions. Aims: Unlike most of the X-ray/optical cluster correlations to date, the present paper focuses on the non-matching objects in either waveband. We investigate how the differences observed between the optical and X-ray catalogues may stem from (1) a shortcoming of the detection algorithms; (2) dispersion in the X-ray/optical scaling relations; or (3) substantial intrinsic differences between the cluster populations probed in the X-ray and optical bands. The aim is to inventory and elucidate these effects in order to account for selection biases in the further determination of X-ray/optical cluster scaling relations. Methods: We correlated the X-CLASS serendipitous cluster catalogue extracted from the XMM archive with the redMaPPer optical cluster catalogue derived from the Sloan Digital Sky Survey (DR8). We performed a detailed and, in large part, interactive analysis of the matching output from the correlation. The overlap between the two catalogues has been accurately determined and possible cluster positional errors were manually recovered. The final samples comprise 270 and 355 redMaPPer and X-CLASS clusters, respectively. X-ray cluster matching rates were analysed as a function of optical richness. In the second step, the redMaPPer clusters were correlated with the entire X-ray catalogue, containing point and uncharacterised sources (down to a few 10-15 erg s-1 cm-2 in the [0.5-2] keV band). A stacking analysis was performed for the remaining undetected optical clusters. Results: We find that all rich (λ ≥ 80) clusters are detected in X-rays out to z = 0.6. Below this redshift, the richness threshold for X-ray detection

Formation of nickel-doped magnetite hollow nanospheres with high specific surface area and superior removal capability for organic molecules

NASA Astrophysics Data System (ADS)

Li, Zhenhu; Ma, Yurong; Qi, Limin

2016-12-01

A strategy for the formation of magnetic Ni x Fe3-x O4 hollow nanospheres with very high specific surface areas was designed through a facile solvothermal method in mixed solvents of ethylene glycol and water in this work. The Ni/Fe ratios and the crystal phases of the Ni x Fe3-x O4 hollow nanocrystals can be readily tuned by changing the molar ratios of Ni to Fe in the precursors. An inside-out Ostwald ripening mechanism was proposed for the formation of uniform Ni x Fe3-x O4 hollow nanospheres. Moreover, the obtained Ni x Fe3-x O4 hollow nanospheres exhibited excellent adsorption capacity towards organic molecules such as Congo red in water. The maximum adsorption capacities of Ni x Fe3-x O4 hollow nanospheres for Congo red increase dramatically from 263 to 500 mg g-1 with the increase of the Ni contents (x) in Ni x Fe3-x O4 hollow nanospheres from 0.2 to 0.85. The synthesized Ni x Fe3-x O4 nanoparticles can be potentially applied for waste water treatment.

Crimean-Congo haemorrhagic fever virus infection in birds: field investigations in Senegal.

PubMed

Zeller, H G; Cornet, J P; Camicas, J L

1994-01-01

In Senegal, wild ground-feeding birds are frequently infested with immature ticks. In two areas where numerous Crimean-Congo haemorrhagic fever (CCHF) virus isolations were obtained from Hyalomma marginatum rufipes adult ticks collected on ungulates, 175 birds were captured and sera collected. CCHF antibodies were detected by ELISA in 6/22 red-beaked hornbills (Tockus erythrorhynchus), 2/11 glossy starlings (Lamprotornis sp.) and 1/3 guinea fowls. The virus was isolated from H. m. rufipes nymphs collected on a hornbill. The role of wild ground-feeding birds in CCHF virus ecology in West Africa is discussed.

Real-Space Bonding Indicator Analysis of the Donor-Acceptor Complexes X3BNY3, X3AlNY3, X3BPY3, and X3AlPY3 (X, Y = H, Me, Cl).

PubMed

Mebs, Stefan; Beckmann, Jens

2017-10-12

Calculations of real-space bonding indicators (RSBI) derived from Atoms-In-Molecules (AIM), Electron Localizability Indicator (ELI-D), Non-Covalent Interactions index (NCI), and Density Overlap Regions Indicator (DORI) toolkits for a set of 36 donor-acceptor complexes X 3 BNY 3 (1, 1a-1h), X 3 AlNY 3 (2, 2a-2h), X 3 BPY 3 (3, 3a-3h), and X 3 AlPY 3 (4, 4a-4h) reveal that the donor-acceptor bonds comprise covalent and ionic interactions in varying extents (X = Y = H for 1-4; X = H, Y = Me for 1a-4a; X = H, Y = Cl for 1b-4b; X = Me, Y = H for 1c-4c; X, Y = Me for 1d-4d; X = Me, Y = Cl for 1e-4e; X = Cl, Y = H for 1f-4f; X = Cl, Y = Me for 1g-4g; X, Y = Cl for 1h-4h). The phosphinoboranes X 3 BPY 3 (3, 3a-3h) in general and Cl 3 BPMe 3 (3f) in particular show the largest covalent contributions and the least ionic contributions. The aminoalanes X 3 AlNY 3 (2, 2a-2h) in general and Me 3 AlNCl 3 (2e) in particular show the least covalent contributions and the largest ionic contributions. The aminoboranes X 3 BNY 3 (1, 1a-1h) and the phosphinoalanes X 3 AlPY 3 (4, 4a-4h) are midway between phosphinoboranes and aminoalanes. The degree of covalency and ionicity correlates with the electronegativity difference BP (ΔEN = 0.15) < AlP (ΔEN = 0.58) < BN (ΔEN = 1.00) < AlN (ΔEN = 1.43) and a previously published energy decomposition analysis (EDA). To illustrate the importance of both contributions in Lewis formula representations, two resonance formulas should be given for all compounds, namely, the canonical form with formal charges denoting covalency and the arrow notation pointing from the donor to the acceptor atom to emphasis ionicity. If the Lewis formula mainly serves to show the atomic connectivity, the most significant should be shown. Thus, it is legitimate to present aminoalanes using arrows; however, for phosphinoboranes the canonical form with formal charges is more appropriate.

The Preparation and Optical Properties of Novel LiLa(MoO4)2:Sm3+,Eu3+ Red Phosphor.

PubMed

Wang, Jiaxi; Luo, Li; Huang, Baoyu; He, Jingqi; Zhang, Wei; Zhao, Weiren; Wang, Jianqing

2018-02-14

Novel LiLa1-x-y(MoO4)2:xSm3+,yEu3+ (in short: LL1-x-yM:xSm3+,yEu3+) double molybdate red phosphors were synthesized by a solid-state reaction at as low temperature as 610 °C. The optimal doping concentration of Sm3+ in LiLa1-x(MoO4)2:xSm3+ (LL1-xM:xSm3+) phosphor is x = 0.05 and higher concentrations lead to emission quenching by the electric dipole-electric dipole mechanism. In the samples co-doped with Eu3+ ions, the absorption spectrum in the near ultraviolet and blue regions became broader and stronger than these of the Sm3+ single-doped samples. The efficient energy transfer from Sm3+ to Eu3+ was found and the energy transfer efficiency was calculated. Under the excitation at 403 nm, the chromaticity coordinates of LL0.95-yM:0.05Sm3+,yEu3+ approach to the NTSC standard values (0.670, 0.330) continuously with increasing Eu3+ doping concentration. The phosphor exhibits high luminous efficiency under near UV or blue light excitation and remarkable thermal stability. At 150 °C, the integrated emission intensity of the Eu3+ remained 85% of the initial intensity at room temperature and the activation energy is calculated to be 0.254 eV. The addition of the LL0.83M:0.05Sm3+,0.12Eu3+ red phosphors can improve the color purity and reduce the correlated color temperature of WLED lamps. Hence, LL1-x-yM:xSm3+,yEu3+ is a promising WLED red phosphor.

Prevalence of vitamin A deficiency in pregnant and lactating women in the Republic of Congo.

PubMed

Samba, Claude; Tchibindat, Félicité; Gourmel, Bernard; Houzé, Patrick; Malvy, Denis

2013-03-01

Vitamin A status in a sample of pregnant and lactating women living in several representative regions of Congo was assessed and compared between August and September 2004. This survey was conducted using a randomized two-stage cluster-sampling method with stratification on 90 clusters, each consisting of at least 15 women. Vitamin A status was determined in a total of 1,054 individuals, using the impression cytology with transfer (ICT) test, the modified relative dose response test (MRDR test) on dried blood spots (DBS), and clinical examination to detect signs of xerophthalmia. The clinical criterion defining vitamin A deficiency was the presence of active xerophthalmia (Bitot's spots [X1B]), active corneal disease), and/or night blindness (XN stage). The prevalence of clinical signs of stage XN and X1B xerophthalmia in the Republic of Congo was found to be 16% and 19% respectively. The prevalence of clinical signs (X1B) was greater in the rural north than in urban areas, with a gradient running from urban (5%) to rural area (33%); 27% of all the ICT tests showed that the subjects were suffering from vitamin A deficiency. The deficiency rates were significantly higher (p < 0.001) in urban surroundings (Brazzaville) than in the rural northern regions. The biochemical MRDR test showed the presence of vitamin A deficiency (> or = 0.06) in 26% of the mothers in Brazzaville compared to 6% in the town of Kouilou; 44% of the women had retinol levels of < 10 microg/dL in the rural north whereas these percentages were significantly lower in the urban areas surveyed (chi-square = 62.30, p < 0.001). A significant correlation was found to exist (p < 0.001) between the ICT test and the MRDR test on DBS. In the population as a whole, 30% of the mothers suffering from malarial attack had abnormally low MRDR levels (> or = 0.06) compared to no malaria. The results of the present study confirm that vitamin A deficiency is a serious public-health issue in pregnant and lactating

Prevalence of Vitamin A Deficiency in Pregnant and Lactating Women in the Republic of Congo

PubMed Central

Tchibindat, Félicité; Gourmel, Bernard; Houzé, Patrick; Malvy, Denis

2013-01-01

Vitamin A status in a sample of pregnant and lactating women living in several representative regions of Congo was assessed and compared between August and September 2004. This survey was conducted using a randomized two-stage cluster-sampling method with stratification on 90 clusters, each consisting of at least 15 women. Vitamin A status was determined in a total of 1,054 individuals, using the impression cytology with transfer (ICT) test, the modified relative dose response test (MRDR test) on dried blood spots (DBS), and clinical examination to detect signs of xerophthalmia. The clinical criterion defining vitamin A deficiency was the presence of active xerophthalmia (Bitot's spots [X1B]), active corneal disease), and/or night blindness (XN stage). The prevalence of clinical signs of stage XN and X1B xerophthalmia in the Republic of Congo was found to be 16% and 19% respectively. The prevalence of clinical signs (X1B) was greater in the rural north than in urban areas, with a gradient running from urban (5%) to rural area (33%); 27% of all the ICT tests showed that the subjects were suffering from vitamin A deficiency. The deficiency rates were significantly higher (p<0.001) in urban surroundings (Brazzaville) than in the rural northern regions. The biochemical MRDR test showed the presence of vitamin A deficiency (≥0.06) in 26% of the mothers in Brazzaville compared to 6% in the town of Kouilou; 44% of the women had retinol levels of <10 μg/dL in the rural north whereas these percentages were significantly lower in the urban areas surveyed (chi-square=62.30, p<0.001). A significant correlation was found to exist (p<0.001) between the ICT test and the MRDR test on DBS. In the population as a whole, 30% of the mothers suffering from malarial attack had abnormally low MRDR levels (≥0.06) compared to no malaria. The results of the present study confirm that vitamin A deficiency is a serious public-health issue in pregnant and lactating mothers in the Republic

(Pt{sub 1–x}Cu{sub x}){sub 3}Cu{sub 2}B and Pt{sub 9}Cu{sub 3}B{sub 5}, the first examples of copper platinum borides. Observation of superconductivity in a novel boron filled β-Mn-type compound

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

Salamakha, Leonid P.; Sologub, Oksana, E-mail: oksana.sologub@univie.ac.at; Stöger, Berthold

New ternary copper platinum borides have been synthesized by arc melting of pure elements followed by annealing at 600 °C. The structures have been studied by X-ray single crystal and powder diffraction. (Pt{sub 1−x}Cu{sub x}){sub 3}Cu{sub 2}B (x=0.33) forms a B-filled β-Mn-type structure (space group P4{sub 1}32; a=0.6671(1) nm). Cu atoms are distributed preferentially on the 8c atom sites, whereas the 12d site is randomly occupied by Pt and Cu atoms (0.670(4) Pt±0.330(4) Cu). Boron is located in octahedral voids of the parent β-Mn-type structure. Pt{sub 9}Cu{sub 3}B{sub 5} (space group P-62m; a=0.9048(3) nm, c=0.2908(1) nm) adopts the Pt{sub 9}Zn{submore » 3}B{sub 5–δ}-type structure. It has a columnar architecture along the short translation vector exhibiting three kinds of [Pt{sub 6}] trigonal prism columns (boron filled, boron semi-filled and empty) and Pt channels with a pentagonal cross section filled with Cu atoms. The striking structural feature is a [Pt{sub 6}] cluster in form of an empty trigonal prism at the origin of the unit cell, which is surrounded by coupled [BPt{sub 6}] and [Pt{sub 6}] trigonal prisms, rotated perpendicularly to the central one. There is no B–B contact as well as Cu–B contact in the structure. The relationships of Pt{sub 9}Cu{sub 3}B{sub 5} structure with the structure of Ti{sub 1+x}Os{sub 2−x}RuB{sub 2} as well as with the structure families of metal sulfides and aluminides have been elucidated. (Pt{sub 1–x}Cu{sub x}){sub 3}Cu{sub 2}B (x=0.3) (B-filled β-Mn-type structure) is a bulk superconductor with a transition temperature of about 2.06 K and an upper critical field μ{sub 0}H{sub C2}(0){sup WHH} of 1.2 T, whereas no superconducting transition has been observed up to 0.3 K in Pt{sub 9}Cu{sub 3}B{sub 5} (Pt{sub 9}Zn{sub 3}B{sub 5–δ}-type structure) from electrical resistivity measurements. - Highlights: • First two copper platinum borides, (Pt{sub 0.67}Cu{sub 0.33}){sub 3}Cu{sub 2}B and Pt{sub 9}Cu

On the molecular interaction between lactoferrin and the dye Red HE-3B. A novel approach for docking a charged and highly flexible molecule to protein surfaces

NASA Astrophysics Data System (ADS)

Grasselli, Mariano; Cascone, Osvaldo; Anspach, F. Birger; Delfino, Jose M.

2002-12-01

Lactoferrin (Lf) is a non-heme, iron binding protein present in many physiological fluids of vertebrates where its main role is the microbicidal activity. It has been isolated by different methods, including dye-affinity chromatography. Red HE-3B is one of the most common triazinic dyes applied in protein purification, but scant knowledge is available on structural details and on the energetics of its interaction with proteins. In this work we present a computational approach useful for identifying possible binding sites for Red HE-3B in apo and holo forms of Lfs from human and bovine source. A new geometrical description of Red HE-3B is introduced which greatly simplifies the conformational analysis. This approach proved to be of particular advantage for addressing conformational ensembles of highly flexible molecules. Predictions from this analysis were correlated with experimentally observed dye-binding sites, as mapped by protection from proteolysis in Red HE-3B/Lf complexes. This method could bear relevance for the screening of possible dye-binding sites in proteins whose structure is known and as a potential tool for the design of engineered protein variants which could be purified by dye-affinity chromatography.

On the molecular interaction between lactoferrin and the dye Red HE-3b. A novel approach for docking a charged and highly flexible molecule to protein surfaces.

PubMed

Grasselli, Mariano; Cascone, Osvaldo; Birger Anspach, F; Delfino, Jose M

2002-12-01

Lactoferrin (Lf) is a non-heme, iron binding protein present in many physiological fluids of vertebrates where its main role is the microbicidal activity. It has been isolated by different methods, including dye-affinity chromatography. Red HE-3B is one of the most common triazinic dyes applied in protein purification, but scant knowledge is available on structural details and on the energetics of its interaction with proteins. In this work we present a computational approach useful for identifying possible binding sites for Red HE-3B in apo and holo forms of Lfs from human and bovine source. A new geometrical description of Red HE-3B is introduced which greatly simplifies the conformational analysis. This approach proved to be of particular advantage for addressing conformational ensembles of highly flexible molecules. Predictions from this analysis were correlated with experimentally observed dye-binding sites, as mapped by protection from proteolysis in Red HE-3B/Lf complexes. This method could bear relevance for the screening of possible dye-binding sites in proteins whose structure is known and as a potential tool for the design of engineered protein variants which could be purified by dye-affinity chromatography.

Enhanced red fluorescence in Sr2Si1-xGexO4:Eu3+ phosphors by the substitution of Si by Ge for white light emitting diodes

NASA Astrophysics Data System (ADS)

Huang, Lihui; Xu, Shiqing; Guo, Meiquan; Wang, Chenyue; Hua, Youjie; Zhao, Shilong; Deng, Degang; Wang, Huanping; Jia, Guohua

2012-07-01

Eu3+-doped Sr2Si1-xGexO4 (x=0-1) phosphors have been prepared by the high temperature solid-state reaction method. The luminescent properties of these phosphors were investigated. Red fluorescence of Eu3+ is enhanced gradually in the samples with increasing substitution of Si by Ge upon the excitation of 393 nm light. The intensity is increased by 50% with full substitution of Si by Ge. These results are originated from the structural changes and the phonon energy reduction in the samples due to the substitution of Si by Ge. The CIE chromaticity coordinates of the phosphors vary slightly around (0.62, 0.37) and all are in the red color region. The results indicate that these phosphors could be promising red phosphors for white light emitting diodes.

Comparative Study of Antimalarial and Other Drugs on G6PD Deficient Red Cells.

DTIC Science & Technology

33063 (1600 mg x day for 6 days) and WR 30090 (690 mg x day for 3- 6 days) demonstrated that these drugs were not hemolytic for G6PD deficient red cells...The studies concerning the effects of DFD on G6PD deficient red cells of the A- and B- variants were completed during the course of this contract...DFD is especially hemolytic even at low single dosages for G6PD deficient red cells of the B- type. The investigations on the new antimalarials WR

Hydrological trends in Congo basin (Central Africa)

NASA Astrophysics Data System (ADS)

Laraque, A.

2015-12-01

The last studies concerning some main Congo basin rivers allowed to subdivide their multi-annual flows into several homogeneous phases. As in West Africa, 1970 was the year of the major hydroclimatic event announcing a weaker flowing period. In the absence of long, reliable and available flow series in the whole Congo basin of 3,8 106km2 area, the present study concerns only the Congo River at Brazzaville/Kinshasa and two of the main tributaries of its right bank, Ubangui at Bangui and Sangha at Ouesso, with hydrologic data available from the first half of the 20th century. For Congo River, in comparison with its secular average, after an excess flow noted during the sixties, a significant drop of 10% occurs in the eighties. However, a return to normal conditions is recorded from 1995. For Ubangui and Sangha, the flows remain weaker since 1970. Within the bi-modal hydrological regimes of Sangha and Congo river, because they are equatorial, we also observe since many years a small decline of the secondary flood of april-june. This phenomenon was emphasized especially these last years and is founded in others rivers of Central Africa, where it reflects the variations of de rainfall patterns and the surfaces features. For the Congo basin, the situation is worrying because that affects the inland waterway transport. Moreover that wakes also the project of junction by a canal of the Congo and Chari basins for fighting against the hydrological decline of Lake Chad.

Structure and Cancer Immunotherapy of the B7 Family Member B7x

PubMed Central

Jeon, Hyungjun; Vigdorovich, Vladimir; Garrett-Thomson, Sarah C.; Janakiram, Murali; Ramagopal, Udupi A.; Abadi, Yael M.; Lee, Jun Sik; Scandiuzzi, Lisa; Ohaegbulam, Kim C; Chinai, Jordan M; Zhao, Ruihua; Yao, Yu; Mao, Ying; Sparano, Joseph A.; Almo, Steven C.; Zang, Xingxing

2014-01-01

SUMMARY B7x (B7-H4 or B7S1) is a member of the B7 family that can inhibit T cell function. B7x protein is absent in most normal human tissues and immune cells, but is overexpressed in human cancers and often correlates with negative clinical outcome. The expression pattern and function of B7x suggest that it may be a potent immunosuppressive pathway in human cancers. Here we determined the crystal structure of human B7x IgV domain at 1.59Å resolution and mapped the epitopes recognized by monoclonal antibodies. We developed a new in vivo system to screen therapeutic monoclonal antibodies against B7x, and found that the clone 1H3 significantly inhibited growth of B7x-expressing tumor in vivo via multiple mechanisms. Furthermore, the surviving mice given 1H3 treatment were resistant to tumor re-challenge. Our data suggest that targeting B7x on tumors is a promising cancer immunotherapy and humanized 1H3 may be efficacious for immunotherapy of human cancers. PMID:25437562

X-Ray Absorbed, Broad-Lined, Red AGN and the Cosmic X-Ray Background

NASA Technical Reports Server (NTRS)

Mushotzky, Richard (Technical Monitor); Wilkes, Belinda

2005-01-01

We have obtained XMM spectra for five red, 2MASS AGN, selected from a sample observed by Chandra to be X-ray bright and to cover a range of hardness ratios. Our results confirm the presence of substantial absorbing material in three sources which have optical classifications ranging from Type 1 to Type 2, with an intrinsically flat (hard) power law continuum indicated in the other two. The presence of both X-ray absorption and broad optical emission lines with the usual strength suggests either a small (nuclear) absorber or a favored viewing angle so as to cover the X-ray source but not the broad emission line region (BELR). A soft excess is detected in all three Type 1 sources. We speculate that this soft X-ray emission may arise in an extended region of ionized gas, perhaps linked with the polarized (scattered) light which is a feature of these sources. The spectral complexity revealed by XMM emphasizes the limitations of the low S/N Chandra data. Overall, the new XMM results strengthen our conclusions (Wilkes et al. 2002) that the observed X-ray continua of red AGN are unusually hard at energies greater than 2 keV. Whether due to substantial line-of-sight absorption or to an intrinsically hard or reflection-dominated spectrum, these 'red' AGN have an observed spectral form consistent with contributing significantly to the missing had absorbed population of the Cosmic X-ray Background (CXRB). When absorption and or reflection is taken into account, all these AGN have power law slopes typical of broad-line (Type 1) AGN (Gamma approximately 1.9). This appears to resolve the spectral paradox which for so long has existed between the CXRB and the AGN thought to be the dominant contributors. It also suggests two scenarios whereby Type 1 AGN/QSOs may be responsible for a significant fraction of the CXRB at energies above 2 keV: 1) X-ray absorbed AGN/QSOs with visible broad emission lines; 2) AGN/QSOs with complex spectra whose hardness greater than 2 keV is not

Tunable multicolor and enhanced red emission of monodisperse CaF2:Yb3+/Ho3+ microspheres via Mn2+ doping

NASA Astrophysics Data System (ADS)

Wang, Rui; Yuan, Maohui; Zhang, Chaofan; Wang, Hongyan; Xu, Xiaojun

2018-05-01

Transition metal ions (e.g. Mn2+) and lanthanide co-doped upconversion (UC) materials have attracted wide attention in recent years due to their promising application in multicolor display. Here, we report the hydrothermal synthesis and characterization of Mn2+ doped monodisperse CaF2:Yb3+/Ho3+ microspheres. The results of X-ray diffraction (XRD) revealed that Mn2+ doping does not change the cubic phase of CaF2 material but will lead to diffraction peaks shifting slightly towards higher angle due to the substitution of larger Ca2+ by the relatively smaller Mn2+. Under the excitation of 980 nm continuous wave (CW) laser, these microspheres exhibit green-yellow-red tuning colors and remarkable enhancement of both red to green ratio (R/G) and red to blue ratio (R/B) when increasing Mn2+ concentration from 0 to 30 mol%. The energy migration process between Ho3+ and Mn2+ was proposed and supported by time-decay and power dependence measurements of Ho3+ UC emission. These upconversion materials may have potential applications in optical devices, color display, nanoscale lasers and biomedical imaging.

Optically stimulated luminescence in x-ray irradiated xSnO-(25-x)SrO-75B2O3 glass

NASA Astrophysics Data System (ADS)

Nanto, H.; Nakagawa, R.; Takei, Y.; Hirasawa, K.; Miyamoto, Y.; Masai, H.; Kurobori, T.; Yanagida, T.; Fujimoto, Y.

2015-06-01

An intense optically stimulated luminescence (OSL) was observed, for the first time, in x-ray irradiated xSnO-(25-x)SrO-75B2O3 glass. It was found that the peak wavelength of OSL emission spectrum and its stimulation spectrum is about 400 nm and 600 nm, respectively. The OSL intensity is depended on the SnO contents (x=0.05-1.5) and the most intense OSL was observed in 1.0 mol% SnO doped glass. It was found that the OSL intensity is increased with increasing x-ray absorbed dose. Fairly good fading characteristics were observed in the x-ray irradiated glass, showing that this glass is useful as a candidate for OSL sensor materials for ionizing radiation monitoring.

The Preparation and Optical Properties of Novel LiLa(MoO4)2:Sm3+,Eu3+ Red Phosphor

PubMed Central

Luo, Li; Huang, Baoyu; He, Jingqi; Zhang, Wei; Zhao, Weiren; Wang, Jianqing

2018-01-01

Novel LiLa1−x−y(MoO4)2:xSm3+,yEu3+ (in short: LL1−x−yM:xSm3+,yEu3+) double molybdate red phosphors were synthesized by a solid-state reaction at as low temperature as 610 °C. The optimal doping concentration of Sm3+ in LiLa1−x(MoO4)2:xSm3+ (LL1−xM:xSm3+) phosphor is x = 0.05 and higher concentrations lead to emission quenching by the electric dipole—electric dipole mechanism. In the samples co-doped with Eu3+ ions, the absorption spectrum in the near ultraviolet and blue regions became broader and stronger than these of the Sm3+ single-doped samples. The efficient energy transfer from Sm3+ to Eu3+ was found and the energy transfer efficiency was calculated. Under the excitation at 403 nm, the chromaticity coordinates of LL0.95−yM:0.05Sm3+,yEu3+ approach to the NTSC standard values (0.670, 0.330) continuously with increasing Eu3+ doping concentration. The phosphor exhibits high luminous efficiency under near UV or blue light excitation and remarkable thermal stability. At 150 °C, the integrated emission intensity of the Eu3+ remained 85% of the initial intensity at room temperature and the activation energy is calculated to be 0.254 eV. The addition of the LL0.83M:0.05Sm3+,0.12Eu3+ red phosphors can improve the color purity and reduce the correlated color temperature of WLED lamps. Hence, LL1−x−yM:xSm3+,yEu3+ is a promising WLED red phosphor. PMID:29443910

Biosorption of Congo Red from aqueous solution onto burned root of Eichhornia crassipes biomass

NASA Astrophysics Data System (ADS)

Roy, Tapas Kumar; Mondal, Naba Kumar

2017-07-01

Biosorption is becoming a promising alternative to replace or supplement the present dye removal processes from dye containing waste water. In this work, adsorption of Congo Red (CR) from aqueous solution on burned root of Eichhornia crassipes ( BREC) biomass was investigated. A series of batch experiments were performed utilizing BREC biomass to remove CR dye from aqueous systems. Under optimized batch conditions, the BREC could remove up to 94.35 % of CR from waste water. The effects of operating parameters such as initial concentration, pH, adsorbent dose and contact time on the adsorption of CR were analyzed using response surface methodology. The proposed quadratic model for central composite design fitted very well to the experimental data. Response surface plots were used to determine the interaction effects of main factors and optimum conditions of the process. The optimum adsorption conditions were found to be initial CR concentration = 5 mg/L-1, pH = 7, adsorbent dose = 0.125 g and contact time = 45 min. The experimental isotherms data were analyzed using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) isotherm equations and the results indicated that the Freundlich isotherm showed a better fit for CR adsorption. Thermodynamic parameters were calculated from Van't Hoff plot, confirming that the adsorption process was spontaneous and exothermic. The high CR adsorptive removal ability and regeneration efficiency of this adsorbent suggest its applicability in industrial/household systems and data generated would help in further upscaling of the adsorption process.

Characterizing the discoloration of EBT3 films in solar UV A+B measurement using red LED

NASA Astrophysics Data System (ADS)

Omar, Ahmad Fairuz; Osman, Ummi Shuhada; Tan, Kok Chooi

2017-09-01

This research article proposes an alternative method to measure the discoloration or the color changes of EBT3 films due to exposure by solar ultraviolet (UV A+B) dose. Common methods to measure the color changes of EBT3 are through imaging technique measured by flatbed scanner and through absorbance spectroscopy measured by visible spectrometer. The research presented in this article measure the color changes of EBT3 through simplified optical system using the combination of light emitting diode (LED) as the light source and photodiode as the detector. In this research, 50 pieces of Gafchromic EBT3 films were prepared with the dimension of 3 cm x 2 cm. Color of the films changed from light green to dark green based on the total accumulated UV dose (mJ/cm2) by each film that depends on the duration of exposure, irradiance level (mW/cm2) and condition of the sky. The exposed films were then taken to the laboratory for its color measurement using absorbance spectroscopy technique and using newly developed simplified optical instrument using LED-photodiode. Results from spectroscopy technique indicate that wavelength within red region exhibit better response in term of linearity and responsivity towards the colors of EBT3 films. Wavelength of 626 nm was then selected as the peak emission wavelength for LED-photodiode absorbance system. UV dose measurement using LEDphotodiode system produced good result with coefficient of determination, R2 of 0.97 and root mean square of error, RMSE of 431.82 mJ/cm2 while comparatively, similar wavelength but analyzed from spectroscopy dataset produced R2 of 0.988 and RMSE of 268.94 mJ/cm2.

Zinc peroxide nanomaterial as an adsorbent for removal of Congo red dye from waste water.

PubMed

Chawla, Sneha; Uppal, Himani; Yadav, Mohit; Bahadur, Nupur; Singh, Nahar

2017-01-01

In the past decade, various natural byproducts, advanced metal oxide composites and photocatalysts have been reported for removal of dyes from water. Although these materials are useful for select applications, they have some limitations such as use at fixed temperature, ultra violet (UV) light and the need for sophisticated experimental set up. These materials can remove dyes up to a certain extent but require long time. To overcome these limitations, a promising adsorbent zinc peroxide (ZnO 2 ) nanomaterial has been developed for the removal of Congo red (CR) dye from contaminated water. ZnO 2 is highly efficient even in the absence of sunlight to remove CR from contaminated water upto the permissible limits set by the World Health Organization (WHO) and the United States- Environmental Protection Agency (US-EPA). The adsorbent has a specific property to adjust the pH of the test solution within 6.5-7.5 range irrespective of acidic or basic nature of water. The adsorption capacity of the material for CR dye was 208mgg -1 within 10min at 2-10pH range. The proposed material could be useful for the industries involved in water purification. The removal of CR has been confirmed by spectroscopic and microscopic techniques. The adsorption data followed a second order kinetics and Freundlich isotherm. Copyright © 2016 Elsevier Inc. All rights reserved.

Elliptic Curve Integral Points on y2 = x3 + 3x ‑ 14

NASA Astrophysics Data System (ADS)

Zhao, Jianhong

2018-03-01

The positive integer points and integral points of elliptic curves are very important in the theory of number and arithmetic algebra, it has a wide range of applications in cryptography and other fields. There are some results of positive integer points of elliptic curve y 2 = x 3 + ax + b, a, b ∈ Z In 1987, D. Zagier submit the question of the integer points on y 2 = x 3 ‑ 27x + 62, it count a great deal to the study of the arithmetic properties of elliptic curves. In 2009, Zhu H L and Chen J H solved the problem of the integer points on y 2 = x 3 ‑ 27x + 62 by using algebraic number theory and P-adic analysis method. In 2010, By using the elementary method, Wu H M obtain all the integral points of elliptic curves y 2 = x 3 ‑ 27x ‑ 62. In 2015, Li Y Z and Cui B J solved the problem of the integer points on y 2 = x 3 ‑ 21x ‑ 90 By using the elementary method. In 2016, Guo J solved the problem of the integer points on y 2 = x 3 + 27x + 62 by using the elementary method. In 2017, Guo J proved that y 2 = x 3 ‑ 21x + 90 has no integer points by using the elementary method. Up to now, there is no relevant conclusions on the integral points of elliptic curves y 2 = x 3 + 3x ‑ 14, which is the subject of this paper. By using congruence and Legendre Symbol, it can be proved that elliptic curve y 2 = x 3 + 3x ‑ 14 has only one integer point: (x, y) = (2, 0).

Photoluminescence properties of a new orange-red-emitting Sm(3+)-La3SbO7 phosphor.

PubMed

Li, Zeng-Mei; Deng, Li-Gang; Zhao, Shan-Cang; Zhang, Shu-Qiu; Guo, Chang-Ying; Liang, Jing-Yun; Yue, Hui; Wan, Chun-Yan

2016-03-01

The antimonate compound La3SbO7 has high chemical stability, lattice stiffness and thermal stability. Orange-red-emitting antimonate-based phosphors La3SbO7:xSm(3+) (x = 0.02, 0.05, 0.08, 0.10, 0.15, 0.20 and 0.25) were synthesized. The phase structure and photoluminescence properties of these phosphors were investigated. The emission spectrum obtained on excitation at 407 nm contained exclusively the characteristic emissions of Sm(3+) at 568, 608, 654 and 716 nm, which correspond to the transitions from (4)G5/2 to (6)H5/2, (6)H7/2, (6)H9/2 and (6)H11/2 of Sm(3+), respectively. The strongest emission was located at 608 nm due to the (4)G5/2→(6)H7/2 transition of Sm(3+), generating bright orange-red light. The critical quenching concentration of Sm(3+) in La3SbO7:Sm(3+) phosphor was determined as 10% and the energy transfer between Sm(3+) was found to be through an exchange interaction. The International Commission on Illumination chromaticity coordinates of the La3SbO7:0.10Sm(3+) phosphors are located in the orange-red region. The La3SbO7:Sm(3+) phosphors may be potentially used as red phosphors for white light-emitting diodes. Copyright © 2015 John Wiley & Sons, Ltd.

Conversion of post consumer waste polystyrene into a high value adsorbent and its sorptive properties for Congo Red removal from aqueous solution.

PubMed

Chaukura, Nhamo; Mamba, Bhekie B; Mishra, Shivani B

2017-05-15

Using post-consumer waste polystyrene (WPS), a conjugated microporous polymer (CMP) was synthesised and activated into a sulphonic-group carrying resin (SCMP). The surface chemistry of the materials showed a decline in both the aromatic CH and aliphatic CH 2 stretching vibrations confirming successful crosslinking. The synthesised polymers were thermally stable with decomposition temperatures above 300 °C, had surface heterogeneity, and BET surface areas of 752 and 510 m 2 /g, respectively. A distribution of pores ranging from meso- to micro-pores was comparable to other CMPs. The materials had maximum adsorption capacities of 500 and 357 mg/g for Congo Red (CR) on CMP and SCMP, respectively. Converting waste polystyrene to an adsorbent is a cost effective way of handling waste and simultaneously providing material for wastewater remediation. Copyright © 2017 Elsevier Ltd. All rights reserved.

The complex metal-rich boride Ti1+xRh2-x+yIr3-yB3 (x=0.68, y=1.06) with a new structure type containing B4 zigzag fragments: Synthesis, crystal chemistry and theoretical calculations

NASA Astrophysics Data System (ADS)

Goerens, Christian; Fokwa, Boniface P. T.

2012-08-01

Polycrystalline samples and single crystals of the new complex boride Ti1+xRh2-x+yIr3-yB3 (x=0.68; y=1.06) were synthesized by arc-melting the elements in a water-cooled copper crucible under an argon atmosphere and characterized by X-Ray diffraction as well as EDX measurements. The crystal structure was refined on the basis of single crystal data. The new phase, which represents a new structure type containing trans zigzag B4 fragments as well as isolated boron atoms crystallizes in the orthorhombic space group Pbam (Nr. 55) with the lattice parameters a=8.620(1) Å, b=14.995(2) Å and c=3.234(1) Å. First-principles density functional theory calculations using the Vienna ab-initio simulation package (VASP) were performed on an appropriate structural model (using a supercell approach) and the experimental crystallographic data could be reproduced accurately. Based on this model, the density of states and crystal orbital Hamilton population (for bonding analysis) were calculated, using the linear muffin-tin orbital atomic sphere approximation (LMTO-ASA) method. According to these calculations, this metal-rich compound should be metallic, as expected. Furthermore, very strong boron-boron interactions are observed in the trans zigzag B4 fragment, which induce a clear differentiation of two types of metal-boron contacts with different strength. The observed three-dimensional metal-metal interaction is in good agreement with the predicted metallic behavior.

X-rays from accretion of red giant winds

NASA Technical Reports Server (NTRS)

Jura, M.; Helfand, D. J.

1984-01-01

X-ray observations of the late-type red giants Mira and R Aqr obtained with the Einstein Observatory are presented, and the general problems of white dwarf accretion from late-type giant winds is considered. The extremely low measured luminosities obtained for the two systems leads to the conclusion that the companions of Mira and R Aqr are most likely low-mass main sequence objects rather than white dwarfs as is usually assumed. The expected X-ray luminosities of true red giant/white dwarf systems are considered, and it is concluded that far too few have been detected if the canonical accretion scenario is adopted. A possible explanation of this situation in terms of grain-dominated Eddington-limited accretion is proposed.

Bacteria-assisted preparation of nano α-Fe2O3 red pigment powders from waste ferrous sulfate.

PubMed

Li, Xiang; Wang, Chuankai; Zeng, Yu; Li, Panyu; Xie, Tonghui; Zhang, Yongkui

2016-11-05

Massive ferrous sulfate with excess sulfuric acid is produced in titanium dioxide industry each year, ending up stockpiled or in landfills as solid waste, which is hazardous to environment and in urgent demand to be recycled. In this study, waste ferrous sulfate was used as a second raw material to synthesize nano α-Fe2O3 red pigment powders with a bacteria-assisted oxidation process by Acidithiobacillus ferrooxidans. The synthesis route, mainly consisting of bio-oxidation, precipitation and calcination, was investigated by means of titration, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence (XRF) to obtain optimum conditions. Under the optimum conditions, nano α-Fe2O3 red pigment powders contained 98.24wt.% of Fe2O3 were successfully prepared, with a morphology of spheroidal and particle size ranged from 22nm to 86nm and averaged at 45nm. Moreover, the resulting product fulfilled ISO 1248-2006, the standards of iron oxide pigments. Copyright © 2016 Elsevier B.V. All rights reserved.

EPR spectroscopic investigations in 15BaO-25Li2O-(60-x) B2O3-xFe2O3 glass system

NASA Astrophysics Data System (ADS)

Bhogi, Ashok; Kumar, R. Vijaya; Kistaiah, P.

2018-05-01

Glasses with composition 15BaO-25Li2O-(60-x) B2O3 -xFe2O3 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1 mol %) were prepared by the conventional melt quenching technique. These glasses were characterized using X-ray diffraction (XRD). Electron paramagnetic resonance (EPR) investigations have been carried out as a function of iron ion concentration. The observed EPR spectra of Fe3+ ion exhibits resonance signals at g= 2.0, 4.3 and 8.0. The resonance signal at g= 4.3 is due to isolated Fe3+ ions in site with rhombic symmetry where as the g= 2.0 resonance signal is attributed to the Fe3+ ions coupled by exchange interaction in a distorted octahedral environment and the signal at g= 8.0 arises from axially distorted sites. The number of spins participating in resonance (N) and its paramagnetic susceptibilities (χ) have also been evaluated. The peak-to-peak line width ΔB for the resonance lines at g ≈ 4.3 and at g ≈ 2.0 is increasing as function of the iron ion content. The line intensity of the resonance centered at g ≈ 4.3 and at g ≈ 2.0 increases up to 0.8 mol% of Fe2O3 and for 1 mol% of Fe2O3 its value is found to decrease. The analysis of these results indicated that the conversion some of Fe3+ cations to Fe2+ ions beyond 0.8 mol%.

Detection of hepatitis B virus infection markers in dried plasma spots among patients in Congo-Brazzaville.

PubMed

Alidjinou, Enagnon Kazali; Moukassa, Donatien; Sané, Famara; Twagirimana Nyenyeli, Séraphin; Akoko, Estina Chandrelle; Mountou, Michèle Valy; Bocket, Laurence; Ibara, Jean-Rosaire; Hober, Didier

2014-03-01

The detection of hepatitis B virus (HBV) infection markers by using dried plasma spots from 32 patients living in Congo has been assessed. Considering frozen plasma samples as gold standard, the sensitivity and specificity of HBV serologic markers detection in dried plasma eluted from filter paper were 100%. The sensitivity and the specificity of HBV DNA detection reached 96% and 100%, respectively, with plasma samples dried on filter paper compared to standard samples. Dried plasma samples can represent an alternative to conventional sampling for HBV detection and management of the infection in developing countries. Copyright © 2014 Elsevier Inc. All rights reserved.

Biosorption of Acid Black 172 and Congo Red from aqueous solution by nonviable Penicillium YW 01: kinetic study, equilibrium isotherm and artificial neural network modeling.

PubMed

Yang, Yuyi; Wang, Guan; Wang, Bing; Li, Zeli; Jia, Xiaoming; Zhou, Qifa; Zhao, Yuhua

2011-01-01

The main objective of this work was to investigate the biosorption performance of nonviable Penicillium YW 01 biomass for removal of Acid Black 172 metal-complex dye (AB) and Congo Red (CR) in solutions. Maximum biosorption capacities of 225.38 and 411.53 mg g(-1) under initial dye concentration of 800 mg L(-1), pH 3.0 and 40 °C conditions were observed for AB and CR, respectively. Biosorption data were successfully described with Langmuir isotherm and the pseudo-second-order kinetic model. The Weber-Morris model analysis indicated that intraparticle diffusion was the limiting step for biosorption of AB and CR onto biosorbent. Analysis based on the artificial neural network and genetic algorithms hybrid model indicated that initial dye concentration and temperature appeared to be the most influential parameters for biosorption process of AB and CR onto biosorbent, respectively. Characterization of the biosorbent and possible dye-biosorbent interaction were confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy. Copyright © 2010 Elsevier Ltd. All rights reserved.

THE tilde{A}-tilde{X} AND tilde{B}-tilde{X} ABSORPTIONS OF NO_3 TRAPPED IN SOLID NEON

NASA Astrophysics Data System (ADS)

Jacox, Marilyn E.; Thompson, Warren E.

2009-06-01

Absorptions arising from the tilde{A}-tilde{X} transition of normal and isotopically substituted NO_3 have been observed between 7500 and 9500 cm^{-1}. Details of the spectra will be discussed and assignments will be proposed. Absorptions arising from the tilde{B}-tilde{X} transition of NO_3, with band origin near 15 000 cm^{-1}, have also been observed for the normal species and two of its isotopologues which possess D_{3h} symmetry. As in the gas phase, the absorptions are broadened because of predissociation. The observed band structure corresponds closely with that reported for the gas-phase molecule.

Cyg X-3: Not seen in high-energy gamma rays by COS-B

NASA Technical Reports Server (NTRS)

Hermsen, W.; Bennett, K.; Bignami, G. F.; Bloemen, J. B. G. M.; Buccheri, R.; Caraveo, P. A.; Mayer-Hasselwander, H. A.; Oezel, M. E.; Pollock, A. M. T.; Strong, A. W.

1985-01-01

COS-B had Cyg X-3 within its field of view during 7 observation periods between 1975 and 1982 for in total approximately 300 days. In the skymaps (70 meV E 5000 meV) of the Cyg-X region produced for each of these observations and in the summed map, a broad complex structure is visible in the region 72 deg approximately less than 1 approximately less than 85 deg, approximately less than 5 deg. No resolved source structure is visible at the position of Cyg X-3, but a weak signal from Cyg X-3 could be hidden in the structured gamma-ray background. Therefore, the data has been searched for a 4.8 h timing signature, as well as for a source signal in the sky map in addition to the diffuse background structure as estimated from tracers of atomic and molecular gas.

Red phosphors for use in high CRI fluorescent lamps

DOEpatents

Srivastava, Alok; Comanzo, Holly; Manivannan, Vankatesan; Setlur, Anant Achyut

2005-11-15

Novel red emitting phosphors for use in fluorescent lamps resulting in superior color rendering index values compared to conventional red phosphors. Also disclosed is a fluorescent lamp including a phosphor layer comprising blends of one or more of a blue phosphor, a blue-green phosphor, a green phosphor and a red a phosphor selected from the group consisting of SrY.sub.2 O.sub.4 :Eu.sup.3+, (Y,Gd)Al.sub.3 B.sub.4 O.sub.12 :Eu.sup.3+, and [(Y.sub.1-x-y-m La.sub.y)Gd.sub.x ]BO.sub.3 :Eu.sub.m wherein y<0.50 and m=0.001-0.3. The phosphor layer can optionally include an additional deep red phosphor and a yellow emitting phosphor. The resulting lamp will exhibit a white light having a color rendering index of 90 or higher with a correlated color temperature of from 2500 to 10000 Kelvin. The use of the disclosed red phosphors in phosphor blends of lamps results in high CRI light sources with increased stability and acceptable lumen maintenance over the course of the lamp life.

Pt@Ag and Pd@Ag core/shell nanoparticles for catalytic degradation of Congo red in aqueous solution

NASA Astrophysics Data System (ADS)

Salem, Mohamed A.; Bakr, Eman A.; El-Attar, Heba G.

2018-01-01

Platinum/silver (Pt@Ag) and palladium/silver (Pd@Ag) core/shell NPs have been synthesized in two steps reaction using the citrate method. The progress of nanoparticle formation was followed by the UV/Vis spectroscopy. Transmission electron microscopy revealed spherical shaped core/shell nanoparticles with average particle diameter 32.17 nm for Pt@Ag and 8.8 nm for Pd@Ag. The core/shell NPs were further characterized by FT-IR and XRD. Reductive degradation of the Congo red dye was chosen to demonstrate the excellent catalytic activity of these core/shell nanostructures. The nanocatalysts act as electron mediators for the transfer of electrons from the reducing agent (NaBH4) to the dye molecules. Effect of reaction parameters such as nanocatalyst dose, dye and NaBH4 concentrations on the dye degradation was investigated. A comparison between the catalytic activities of both nanocatalysts was made to realize which of them the best in catalytic performance. Pd@Ag was the higher in catalytic activity over Pt@Ag. Such greater activity is originated from the smaller particle size and larger surface area. Pd@Ag nanocatalyst was catalytically stable through four subsequent reaction runs under the utilized reaction conditions. These findings can thus be considered as possible economical alternative for environmental safety against water pollution by dyes.

Seeing Red and Shooting Blanks: A Study of Red Quasars and Blank Field X-Ray Sources

NASA Technical Reports Server (NTRS)

Elvis, Martin; Oliversen, Ronald J. (Technical Monitor)

2002-01-01

We have identified a population of 'blank field sources' (or 'blanks') among the ROSAT (Roentgen Satellite) bright unidentified X-ray sources with faint optical counterparts. The extreme X-ray over optical flux ratio of blank field sources is not compatible with the main classes of X-ray emitters except for extreme BL Lacertae objects at fx/fv is equal to or less than 35. From the analysis of ROSAT archival data we found evidence for only three sources, out of 16, needing absorption in excess of the Galactic value and no indication of variability. We also found evidence for an extended nature for only one of the five blanks with a serendipitous HRI (High Resolution Imager) detection; this source (1WGA J1226.9+3332) was confirmed as a z=0.89 cluster of galaxies. Palomar images reveal the presence of a red (O - E is equal to or greater than 2) counterpart in the X-ray error circle for six blanks. The identification process brought to the discovery of another high z cluster of galaxies, one (possibly extreme) BL Lac and two apparently normal type 1 AGNs (Active Galactic Nuclei). These AGNs, together with four more AGN-like objects seem to form a well defined group: they present type 1 X-ray spectra but red Palomar counterparts. We discuss the possible explanations for the discrepancy between the X-ray and optical data, among which: a suppressed big blue bump emission, an extreme dust to gas (approximately 40 - 60 the Galactic ratio) ratio value and a high redshift (z is greater than or equal to 3.5) QSO (Quasi-Stellar Object) nature. These AGN-like blanks seem to be the bright (and easier to study) analogs of the sources which are being found in deep Chandra observations. Five more blanks have a still an unknown nature.

(Pt1-xCux)3Cu2B and Pt9Cu3B5, the first examples of copper platinum borides. Observation of superconductivity in a novel boron filled β-Mn-type compound

NASA Astrophysics Data System (ADS)

Salamakha, Leonid P.; Sologub, Oksana; Stöger, Berthold; Michor, Herwig; Bauer, Ernst; Rogl, Peter F.

2015-09-01

New ternary copper platinum borides have been synthesized by arc melting of pure elements followed by annealing at 600 °C. The structures have been studied by X-ray single crystal and powder diffraction. (Pt1-xCux)3Cu2B (x=0.33) forms a B-filled β-Mn-type structure (space group P4132; a=0.6671(1) nm). Cu atoms are distributed preferentially on the 8c atom sites, whereas the 12d site is randomly occupied by Pt and Cu atoms (0.670(4) Pt±0.330(4) Cu). Boron is located in octahedral voids of the parent β-Mn-type structure. Pt9Cu3B5 (space group P-62m; a=0.9048(3) nm, c=0.2908(1) nm) adopts the Pt9Zn3B5-δ-type structure. It has a columnar architecture along the short translation vector exhibiting three kinds of [Pt6] trigonal prism columns (boron filled, boron semi-filled and empty) and Pt channels with a pentagonal cross section filled with Cu atoms. The striking structural feature is a [Pt6] cluster in form of an empty trigonal prism at the origin of the unit cell, which is surrounded by coupled [BPt6] and [Pt6] trigonal prisms, rotated perpendicularly to the central one. There is no B-B contact as well as Cu-B contact in the structure. The relationships of Pt9Cu3B5 structure with the structure of Ti1+xOs2-xRuB2 as well as with the structure families of metal sulfides and aluminides have been elucidated. (Pt1-xCux)3Cu2B (x=0.3) (B-filled β-Mn-type structure) is a bulk superconductor with a transition temperature of about 2.06 K and an upper critical field μ0HC2(0)WHH of 1.2 T, whereas no superconducting transition has been observed up to 0.3 K in Pt9Cu3B5 (Pt9Zn3B5-δ-type structure) from electrical resistivity measurements.

Crimean-Congo Hemorrhagic Fever.

PubMed

Shayan, Sara; Bokaean, Mohammad; Shahrivar, Mona Ranjvar; Chinikar, Sadegh

2015-01-01

Crimean-Congo hemorrhagic fever virus (CCHFV) is a member of the Bunyaviridae family and Nairovirus genus. The viral genome consists of 3 RNA segments of 12 kb (L), 6.8 kb (M), and 3 kb (S). Crimean-Congo hemorrhagic fever (CCHF) is the most widespread tickborne viral infection worldwide: it has been reported in many regions of Africa, the Middle East, and Asia. The geographical distribution of CCHFV corresponds most closely with the distribution of members of the tick genera, and Hyalomma ticks are the principal source of human infection. In contrast to human infection, CCHFV infection is asymptomatic in all species. Treatment options for CCHF are limited; immunotherapy and ribavirin are effective in the treatment of CCHF; the efficacy of ribavirin in the treatment of CCHF has not yet been proven. This article reviews the history, epidemiology, clinical symptoms, pathogenesis, diagnosis, and treatment of CCHFV, as well as the development of a vaccine against it.

A search for soft X-ray emission from red-giant coronae

NASA Technical Reports Server (NTRS)

Margon, B.; Mason, K. O.; Sanford, P. W.

1974-01-01

Hills has pointed out that if red-giant coronae are weak sources of soft X-rays, then the problems of the identification of the local component of the soft X-ray background and the observed lack of gas in globular clusters may be simultaneously resolved. Using instrumentation aboard OAO Copernicus, we have searched unsuccessfully for emission in the 10-100 A band from four nearby red giants. In all cases, our upper limits are of the order of the minimum theoretically predicted fluxes.

3D stratigraphic modeling of the Congo turbidite system since 210 ka: an investigation of factors controlling sedimentation

NASA Astrophysics Data System (ADS)

Laurent, Dimitri; Picot, Marie; Marsset, Tania; Droz, Laurence; Rabineau, Marina; Granjeon, Didier; Molliex, Stéphane

2017-04-01

The geometry and internal functioning of turbidite systems are relatively well-constrained today. However, the respective role of autogenic (topographic compensation, dynamics of turbidity currents…) and allogenic factors (tectonics, sea-level, climate) governing their architectural evolution is still under debate. The geometry of the Quaternary Congo Fan is characterized by successive sedimentary prograding/retrograding cycles bounded by upfan avulsions, reflecting a periodic control of sedimentation (Picot et al., 2016). Multi-proxy studies revealed a strong interplay between autogenic control and climate forcing as evidenced by changes in fluvial sediment supplies consistent with arid and humid periods in the Congo River Basin. In the light of these results, the aim of this study is to investigate the relative impact of internal and external forcing factors controlling, both in time and space, the formation and evolution of depocenters of the Congo Deep-Sea Fan since 210 ka. This work represents the first attempt to model in 3D the stratigraphic architecture of the Congo turbidite system using DionisosFlow (IFP-EN), a diffusion process-based software. It allows the simulation of sediment transport and the 3D geometry reproduction of sedimentary units based on physical processes such as sea level changes, tectonics, sediment supply and transport. According to the modeling results, the role of topographic compensation in the deep-sea fan geometry is secondary compared to climate changes in the drainage basin. It appears that a periodic variation of sediment discharge and water flow is necessary to simulate the timing and volume of prograding/retrograding sedimentary cycles and more particularly the upfan avulsion events. The best-fit simulations show that the overriding factor for such changes corresponds to the expansion of the vegetation cover in the catchment basin associated to the Milankovitch cycle of precession which controlled the West African Monsoon

Augmentation of chemokine production by severe acute respiratory syndrome coronavirus 3a/X1 and 7a/X4 proteins through NF-kappaB activation.

PubMed

Kanzawa, Noriyuki; Nishigaki, Kazuo; Hayashi, Takaya; Ishii, Yuichi; Furukawa, Souichi; Niiro, Ayako; Yasui, Fumihiko; Kohara, Michinori; Morita, Kouichi; Matsushima, Kouji; Le, Mai Quynh; Masuda, Takao; Kannagi, Mari

2006-12-22

Severe acute respiratory syndrome (SARS) is characterized by rapidly progressing respiratory failure resembling acute/adult respiratory distress syndrome (ARDS) associated with uncontrolled inflammatory responses. Here, we demonstrated that, among five accessory proteins of SARS coronavirus (SARS-CoV) tested, 3a/X1 and 7a/X4 were capable of activating nuclear factor kappa B (NF-kappaB) and c-Jun N-terminal kinase (JNK), and significantly enhanced interleukin 8 (IL-8) promoter activity. Furthermore, 3a/X1 and 7a/X4 expression in A549 cells enhanced production of inflammatory chemokines that were known to be up-regulated in SARS-CoV infection. Our results suggest potential involvement of 3a/X1 and 7a/X4 proteins in the pathological inflammatory responses in SARS.

RED CELL STROMA PROTEIN RICH IN VITAMIN B12 DURING ACTIVE REGENERATION

PubMed Central

Whipple, G. H.; Robscheit-Robbins, F. S.; Bale, W. F.

1955-01-01

During active blood regeneration in anemia in dogs an increase occurs in the stroma protein of the red cells. When vitamin B12 with radioactive cobalt is given at the start of this blood regeneration one finds concentration of labeled B 12 in the stroma protein but not in the hemoglobin. After the acute phase of red cell regeneration is ended the concentration of B12 in stroma protein falls rapidly to very low levels within 2 weeks. Subsequent episodes of red blood cell regeneration seems not to cause remobilization of radioactive cobalt into red cells from other body stores. It appears that the vitamin B12 is a factor of importance in the first steps of stroma protein formation in the first few days of the life of the red cell in the dog. This response in dogs and the response in pernicious anemia to vitamin B12 may have some points in common. Distribution of the B12-radioactive cobalt in the organs and tissues at autopsy has been recorded. Some very suggestive localizations were noted and some variation 1 week and 7 weeks after B12 injections. Radioactive cobalt escapes in the urine during the weeks following B12 injections. PMID:13271685

Dispersion of single-wall carbon nanotubes with supramolecular Congo red - properties of the complexes and mechanism of the interaction.

PubMed

Jagusiak, Anna; Piekarska, Barbara; Pańczyk, Tomasz; Jemioła-Rzemińska, Małgorzata; Bielańska, Elżbieta; Stopa, Barbara; Zemanek, Grzegorz; Rybarska, Janina; Roterman, Irena; Konieczny, Leszek

2017-01-01

A method of dispersion of single-wall carbon nanotubes (SWNTs) in aqueous media using Congo red (CR) is proposed. Nanotubes covered with CR constitute the high capacity system that provides the possibility of binding and targeted delivery of different drugs, which can intercalate into the supramolecular, ribbon-like CR structure. The study revealed the presence of strong interactions between CR and the surface of SWNTs. The aim of the study was to explain the mechanism of this interaction. The interaction of CR and carbon nanotubes was studied using spectral analysis of the SWNT-CR complex, dynamic light scattering (DLS), differential scanning calorimetry (DSC) and microscopic methods: atomic force microscopy (AFM), transmission (TEM), scanning (SEM) and optical microscopy. The results indicate that the binding of supramolecular CR structures to the surface of the nanotubes is based on the "face to face stacking". CR molecules attached directly to the surface of the nanotubes can bind further, parallel-oriented molecules and form supramolecular and protruding structures. This explains the high CR binding capacity of carbon nanotubes. The presented system - containing SWNTs covered with CR - offers a wide range of biomedical applications.

On the oxidation of the three-dimensional aromatics [B(12)X(12)](2-) (X=F, Cl, Br, I).

PubMed

Boeré, René T; Derendorf, Janis; Jenne, Carsten; Kacprzak, Sylwia; Kessler, Mathias; Riebau, Rainer; Riedel, Sebastian; Roemmele, Tracey L; Rühle, Monika; Scherer, Harald; Vent-Schmidt, Thomas; Warneke, Jonas; Weber, Stefan

2014-04-07

The perhalogenated closo-dodecaborate dianions [B12 X12 ](2-) (X=H, F, Cl, Br, I) are three-dimensional counterparts to the two-dimensional aromatics C6 X6 (X=H, F, Cl, Br, I). Whereas oxidation of the parent compounds [B12 H12 ](2-) and benzene does not lead to isolable radicals, the perhalogenated analogues can be oxidized by chemical or electrochemical methods to give stable radicals. The chemical oxidation of the closo-dodecaborate dianions [B12 X12 ](2-) with the strong oxidizer AsF5 in liquid sulfur dioxide (lSO2 ) yielded the corresponding radical anions [B12 X12 ](⋅-) (X=F, Cl, Br). The presence of radical ions was proven by EPR and UV/Vis spectroscopy and supported by quantum chemical calculations. Use of an excess amount of the oxidizing agent allowed the synthesis of the neutral perhalogenated hypercloso-boranes B12 X12 (X=Cl, Br). These compounds were characterized by single-crystal X-ray diffraction of dark blue B12 Cl12 and [Na(SO2 )6 ][B12 Br12 ]⋅B12 Br12 . Sublimation of the crude reaction products that contained B12 X12 (X=Cl, Br) resulted in pure dark blue B12 Cl12 or decomposition to red B9 Br9 , respectively. The energetics of the oxidation processes in the gas phase were calculated by DFT methods at the PBE0/def2-TZVPP level of theory. They revealed the trend of increasing ionization potentials of the [B12 X12 ](2-) dianions by going from fluorine to bromine as halogen substituent. The oxidation of all [B12 X12 ](2-) dianions was also studied in the gas phase by mass spectrometry in an ion trap. The electrochemical oxidation of the closo-dodecaborate dianions [B12 X12 ](2-) (X=F, Cl, Br, I) by cyclic and Osteryoung square-wave voltammetry in liquid sulfur dioxide or acetonitrile showed very good agreement with quantum chemical calculations in the gas phase. For [B12 X12 ](2-) (X=F, Cl, Br) the first and second oxidation processes are detected. Whereas the first process is quasi-reversible (with oxidation potentials in the range between +1

(3+1)D superspace structural determination of two new modulated composite phases: Sr 1+ x(Cu xMn 1- x)O 3; x=3/11 and x=0.3244

NASA Astrophysics Data System (ADS)

El Abed, Ahmed; Gaudin, Etienne; zur Loye, Hans-Conrad; Darriet, Jacques

2003-01-01

We report the structure determination of two new phases belonging to the A 1+ x(A' xB 1- x)O 3 family of oxides with A=Sr, A'=Cu, and B=Mn, where x=3/11 and x=0.3244, corresponding to a commensurate and incommensurate composite structure, respectively. These two compounds are the first examples of oxides belonging to the Sr 1+ x(Cu xMn 1- x)O 3 family. Their structures were solved in the (3+1) dimensional superspace formalism as modulated composite structures with two subsystems [(Cu,Mn)O 3] and [Sr]. The superspace group used to solve the structures is R 3¯m(00γ)0s . The first phase ( x=3/11), corresponding to the chemical formula Sr 14Cu 3Mn 8O 33, was obtained as a single crystal with unit cell parameters of a=9.6025(3) Å and c1=2.5660(8) Å ( q=7/11 c1∗, Z=3), where c1 is the lattice parameter corresponding to the c-axis of the trigonal subsystem [(Cu,Mn)O 3]. The second phase ( x=0.3244(1)), is a polycrystalline sample with unit cell parameters of a=9.5933(7) and c1=2.5933(3) ( q=0.6622 c1∗, Z=3). In both structures, one dimensional chains run along the c-axis which contain octahedra and trigonal prisms occupied by manganese and copper atoms, respectively. The refinement results show that in both cases copper occupies the rectangular faces of the trigonal prism while manganese occupies the octahedral sites. The magnetic measurements of the polycrystalline phase (Sr 1+ x(Cu xMn 1- x)O 3, x=0.3244(2)) and the Curie constant obtained from the high temperature susceptibility are in agreement with a spin state configuration of S=3/2 for Mn 4+ and S=1/2 for Cu 2+.

Congo (Brazzaville) Country Analysis Brief

EIA Publications

2014-01-01

Congo (Brazzaville) is among the top five oil producers in Sub-Saharan Africa. Oil production comes almost entirely from offshore oil fields. Congo exports almost all of its oil production, and the largest recipients are China and the European Union.

Atomistic study on the site preference and lattice vibration of Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} (T=Al and Ge)

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

Cheng, Hai-Xia; Wang, Xiao-Xu; Department of Materials Engineering, National Ping Tung University of Technology and Science, Ping-Tung 91201, Taiwan

The effects of the Y substitution for Gd on the structural stability and the site preference of intermetallics Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} (T=Al and Ge) are studied by using a series of interatomic pair potentials. The calculated results show Y can stabilize Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} with the tetragonal structure, and Y substitute for Gd with a strong preference for the 2b sites. The calculated lattice parameters are in good agreement with the experimental data. Furthermore, the total and partial phonon densities of states are evaluated for the Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} compounds withmore » the tetragonal structure. A qualitative analysis is carried out with the relevant potentials for the vibrational modes, which makes it possible to predict some properties related to lattice vibration. - Graphical abstract: The lattice cell of Gd{sub 3}Co{sub 29}T{sub 4}B{sub 10} consists of 92 atoms, or two Gd{sub 3}Co{sub 29}T{sub 4}B{sub 10} formula units, with fourteen distinct kinds of site. Rare-earth atoms occupy 2b and 4d sites, Co atoms occupy the Co1(2c), Co2(8i1), Co3(8i2), Co4(8i3), Co5(8j1), Co6(8j2) and Co7(16k), T atoms occupy the T(8i) sites, and B atoms occupy the B1(2c1), B2(2c2), B3(8i) and B4(8j) sites. - Highlights: • The application of the pair potentials obtained from lattice-inversion method. • The lattice vibrations for Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} (T=Ge and Al) are first evaluated. • The Y atoms should prefer the 2b site of Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} compounds. • The total and partial phonon densities of states are evaluated for the Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} compounds with the tetragonal structure. • A qualitative analysis is carried out with the relevant potentials for the vibrational modes.« less

Pore-fluid chemistry along the main axis of an active lobe at the Congo deep-sea fan

NASA Astrophysics Data System (ADS)

Croguennec, C.; Ruffine, L.; Guyader, V.; Le Bruchec, J.; Ruesch, B.; Caprais, J.; Cathalot, C.; de Prunelé, A.; Germain, Y.; Bollinger, C.; Dennielou, B.; Olu, K.; Rabouille, C.

2013-12-01

The distal lobes of the Congo deep-sea fan constitute a unique in situ laboratory to study early diagenesis of marine sediments. They are located at water depth of about 5000 m and result from the deposition of sediment transported by turbidity currents along the channel-levee systems and submarine canyon connected to the Congo River. Thus, a huge amount of organic matter, transported from the river to the lobes, undergoes decomposition processes involving different oxidants present within the sedimentary column. This drastically changes the chemistry of the pore fluids, allowing the occurence of a succession of biogeochemical processes. The present study is part of an ongoing project which aims at better understanding the role and the fate of organic matter transported to the lobe systems, as well as its implication in the distribution of the living communities encountered there. Thus, pore fluids have been sampled from 8 Calypso cores in order to determine the concentration of dissolved elements. Five sites have been investigated: four of them are located along the main axis of a currently active lobe, the last one being located on a lobe disconnected from the chenals. The analyses of methane, major (Cl, SO4, Mg, Ca, K, Na) and minor (Sr, Ba, B, Li, Mn) elements have been carried out along with total alkalinity determination. The resulting profiles show a highly heterogeneous pore-fluid chemistry. Sulphate concentration near the seawater/sediment interface varies from 3 to 29 mM, indicating intense sulphate reduction. Surprisingly the lowest values are found at the site which is disconnected from the active lobe. The manganese cycle is well defined for all cores. The core recovered at the more distal lobe exhibits very peculiar pore-fluid profiles which are likely related to a geological event, most likely sediment slide and remobilization. References: Babonneau, N., Savoye, B., Cremer, M. & Klein, B., 2002. Morphology and architecture of the present canyon and

Crystal Growth and Luminescence Properties of Yb-doped Gd3Al2Ga3O12 Infra-red Scintillator

NASA Astrophysics Data System (ADS)

Suzuki, Akira; Kurosawa, Shunsuke; Nagata, Shinji; Yamamura, Tomoo; Pejchal, Jan; Yamaji, Akihiro; Yokota, Yuui; Shirasaki, Kenji; Homma, Yoshiya; Aoki, Dai; Shikama, Tatsuo; Yoshikawa, Akira

2014-07-01

1-mol%-Yb-doped Gd3Al2Ga3O12 infra-red scintillator crystal has been studied as a novel implantable radiation monitor in radiation therapy. Powder X-ray diffraction measurement and chemical analysis with a field emission scanning microscope and wavelength dispersive spectrometer determined its garnet structure and average chemical composition of Yb0.03±0.01Gd2.99±0.07Al2.21±0.08Ga2.64±0.09O12.10±0.09. Transmittance measurements reached high values of approximately 70% in the human body transparency region between 650 to 1200 nm. Photoluminescence peaks were detected around 970 and 1030 nm under the 940 nm excitation with a Xe lamp. Infra-red scintillation emissions were clearly observed around 970 and 1030 nm due to Yb3+ 4f-4f transitions under X-ray excitation. Therefore, these results suggest that Yb-doped Gd3Al2Ga3O12 might be used as an infra-red scintillator material.

Phase stability, crystal structure and magnetism in (U1-xNbx)2 Ni21B6 and (UyNb1-y)3Ni20B6

NASA Astrophysics Data System (ADS)

Provino, Alessia; Bhattacharya, Amitava; Dhar, Sudesh K.; Pani, Marcella; Gatti, Flavio; Paudyal, Durga; Manfrinetti, Pietro

Ternary phases with composition T2M21X6 and T3M20X6 (T = transition metal; M = 3 d metal; X = B, C, P) are reported to crystallize with the W2Cr21C6-type and Mg3Ni20B6-type, respectively (ternary ordered derivatives of the cubic Cr23C6-type, cF116). They attract interest due to their refractory, mechanical, and peculiar magnetic properties. Literature data on these compounds only concern apparently stoichiometric 2:21:6 and 3:20:6 phases. Often only nominal composition has been reported, with few structural refinements and no measurements of physical properties. Lack of detailed stoichiometry and crystallographic data does not allow sufficient understanding of the crystal chemistry and properties of these compounds. We studied stability, crystal structure and magnetism of (U1-xNbx)2 Ni21B6 and (UyNb1-y)3Ni20B6; stable phases are U2Ni21B6 and Nb3Ni20B6, as also confirmed by theoretical calculations. The two pristine compounds solubilize Nb and U, respectively, up to a given extent. The substitution of U by Nb leads to a structural change from the W2Cr21C6- to the Mg3Ni20B6-type. While U2Ni21B6 is a Pauli paramagnet (itinerant non-magnetic state of U-5 f electrons), in agreement with literature, magnetization data for (UyNb1-y)3 Ni20B6 show itinerant ferromagnetism with TC >300 K.

Fragility Index variation in (Li2O)x(B2O3) 100-x melts

NASA Astrophysics Data System (ADS)

Skipper, Charles; Chbeir, Ralph; Mohanty, Chandi; Boolchand, Punit

We have measured the fragility index (m) of titled melts as a function of Li2O content in the 0<x<35% range using Modulated DSC. In this approach, one measures the real and imaginary part of the complex specific heat as a function of modulation frequency (ν) , and deduces an activation energy by plotting the log of the enthalpy relaxation time as a function of inverse Temperature obtained at various ν. For pure B2O3 glass with a Tg = 308°C, we obtain m = 28 (1). With increasing x, m is found to monotonically increase to 38(1) as x increased to 15%, but then to plateau at a value of m = 42(2) in the range 18%<x<25%. These values in m are significantly lower than those reported earlier. In particular, the range of x where we observe a plateau in m, authors of ref. 1 observed a linear increase in the 41x across which a plateau is observed also happens to coincide where the isostatically rigid Intermediate Phase reported recently.

Hydraulic characterization of the middle reach of the Congo River

NASA Astrophysics Data System (ADS)

O'Loughlin, F.; Trigg, M.; Schumann, G.; Bates, P. D.

2012-12-01

Little is known about the hydraulics of the Congo River compared to other large rivers, such as the Amazon, Nile and Mississippi, despite it draining an area greater than 3.7 million square kilometers and being the seconded largest river in terms of discharge. While there has been some study of the Congo Basin, most of these concentrate on ecology or the human aspects, but few look at the either the hydrology or hydraulic characteristics of the river. Of the published hydrology/hydraulic research, most concentrates on the hydrology of the Congo Basin aiming to alleviate some of the issues relating to a sparse river gauging network that currently exists. Even fewer studies have looked at hydraulics of the Congo, and usually over a relatively small area of the basin. To undertake a larger study area requires more details on the characteristics of the Congo River. The Congo River can be divided into three distinct reaches; the upper, middle and lower reaches. We concentrate on the middle reach which starts upstream at Boyoma falls, just south of Kisangani, and ends downstream at Livingstone Falls, at Kinshasa (DRC), Brazzaville (Congo) and the Pool Malebo. From Kisangani to Kinshasa, the middle Congo crosses the equator twice and is join by two large tributaries (Ubangi, Kasai) and is highly braided. The middle reach of the Congo is especially important as its still largely undisturbed wetlands are the seconded largest tropical wetlands globally. It is also the main transportation link between Kisangani and Kinshasa, the two largest cities in the DRC. By utilizing remotely sensed Landsat and Icesat datasets, we present the first detailed study on the hydraulic characterization of the middle reach of the Congo River. With these datasets we identify the main control points of flow in the middle reach, investigate how the water surface slope, channel width, islands and braids vary between high and low flows and spatially along the reach. We compare the middle reach of

Strain-induced tetragonal distortions and multiferroic properties in polycrystalline Sr1 -xB axMn O3 (x =0.43 -0.45 ) perovskites

NASA Astrophysics Data System (ADS)

Somaily, H.; Kolesnik, S.; Mais, J.; Brown, D.; Chapagain, K.; Dabrowski, B.; Chmaissem, O.

2018-05-01

We report the structure-property phase diagram of unique single-ion type-1 multiferroic pseudocubic Sr1 -xB axMn O3 perovskites. Employing a specially designed multistep reduction-oxidation synthesis technique, we have synthesized Sr1 -xB axMn O3 compositions in their polycrystalline form with a significantly extended Ba solubility limit that is only rivaled by a very limited number of crystals and thin films grown under nonequilibrium conditions. Understanding the multiferroic interplay with structure in Sr1 -xB axMn O3 is of great importance as it opens the door wide to the development of newer materials from the parent (A A' ) (B B' ) O3 system with enhanced properties. To this end, using a combination of time-of-flight neutron and synchrotron x-ray scattering techniques, we determined the exact structures and quantified the Mn and oxygen polar distortions above and below the ferroelectric Curie temperature TC and the Néel temperature TN. In its ferroelectric state, the system crystalizes in the noncentrosymmetric tetragonal P 4 m m space group, which gives rise to a large electric dipole moment Ps, in the z direction, of 18.4 and 29.5 μ C /c m2 for x =0.43 and 0.45, respectively. The two independently driven ferroelectric and magnetic order parameters are single-handedly accommodated by the Mn sublattice leading to a novel strain-assisted multiferroic behavior in agreement with many theoretical predictions. Our neutron diffraction results demonstrate the large and tunable suppression of the ferroelectric order at the onset of AFM ordering and confirm the coexistence and strong coupling of the two ferroic orders below TN. The refined magnetic moments confirm the strong covalent bonding between Mn and the oxygen anions, which is necessary for stabilizing the ferroelectric phase.

Utilization Chitosan-p-t-Butylcalix[4]Arene for Red MX 8B Adsorbent

NASA Astrophysics Data System (ADS)

Handayani, D. S.; Kusumaningsih, T.; Hak, L. A.

2017-02-01

Adsorption of Procion Red MX 8B using chitosan dan chitosan-linked p-t-butylcalix[4]arene has been done. The research aimed to understand the adsorption of Procion Red MX 8B using chitosan p-t-butylcalix[4]arene compared to ordinary chitosan. The research was conducted in a batch process varying in pH, contact time and initial concentration of the Procion Red MX 8B. The amount of dye adsorbed was determined using UV-Vis spectrophotometer and the adsorben was characterized using FTIR and SEM-EDX spectrophotometer. The result showed that the optimum condition was achieved when the pH was set at 4, contact time 135 minutes and initial concentration at 200 ppm. The kinetic analysis showed that the adsorption followed Ho kinetic model and pseudo second order with the adsorption rate constant was 3.69×10-3 g/mg.minute and 2.03×10-3 g/mg.minute. The isotherm analysis showed that the adsorption process tend to occur following the Langmuir model with maximum capacity for chitosan and chitosan-linked p-t-butylcalix[4]arene 136.09 mg/g and 147.35 mg/g respectively. The adsorption energy of chitosan and chitosan-linked p-t-butylcalix[4]arene at 30.53 kJ/mole and 33.65 kJ/mole.

Discovery of novel solid solution Ca3Si3-x O3+x N4-2x : Eu2+ phosphors: structural evolution and photoluminescence tuning.

PubMed

Wang, Baochen; Liu, Yan-Gai; Huang, Zhaohui; Fang, Minghao; Wu, Xiaowen

2017-12-22

Discovery of novel phosphors is one of the main issues for improving the color rendering index (CRI) and correlated color temperature (CCT) of white light-emitting diodes (w-LEDs). This study mainly presents a systematic research on the synthesis, crystal structure variation and photoluminescence tuning of novel (oxy)nitride solid solution Ca 3 Si 3-x O 3+x N 4-2x : Eu 2+ phosphors. XRD refinements show that lattice distortion occurs when x value diverges the optimum one (x = 1). The lattice distortion causes a widening of emission spectrum and an increase of Stokes shift (ΔSS), which leads to a bigger thermal quenching. With decrease of x value, the emission spectrum shows an obvious red-shift from 505.2 to 540.8 nm, which is attributed to the crystal field splitting. The enhanced crystal field splitting also broadens the excitation spectrum, making it possible to serve as the phosphor for near ultraviolet (n-UV) LEDs. A 3-phosphor-conversion w-LED lamp was fabricated with the as-prepared phosphor, which exhibits high CRI (Ra = 85.29) and suitable CCT (4903.35 K). All these results indicate that the Ca 3 Si 3-x O 3+x N 4-2x : Eu 2+ phosphor can serve as the green phosphor for n-UV w-LEDs, with a tunable spectrum by controlling the crystal structure and morphology.

ELECTRON IMPACT DISSOCIATION X {sup 1}{Sigma}{sup +} {sub g} {yields} b {sup 3}{Sigma} {sub u} {sup +} AND EXCITATIONS X {sup 1}{Sigma}{sup +} {sub g} {yields} a {sup 3}{Sigma} {sub g} {sup +} AND X {sup 1}{Sigma}{sup +} {sub g} {yields} B {sup 1}{Sigma} {sub u} {sup +} OF MOLECULAR HYDROGEN IN NONTHERMAL ASTROPHYSICAL PLASMAS

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

Ki, Dae-Han; Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr

We investigate the electronic transitions X {sup 1}{Sigma}{sup +} {sub g} {yields} b {sup 3}{Sigma} {sub u} {sup +}, X {sup 1}{Sigma}{sup +} {sub g} {yields} a {sup 3}{Sigma} {sub g} {sup +}, and X {sup 1}{Sigma}{sup +} {sub g} {yields} B {sup 1}{Sigma} {sub u} {sup +} of molecular hydrogen by studying electron impacts in astrophysical Lorentzian plasmas. Useful fitting formulae for the X {sup 1}{Sigma}{sup +} {sub g} {yields} b {sup 3}{Sigma} {sub u} {sup +}, X {sup 1}{Sigma}{sup +} {sub g} {yields} a {sup 3}{Sigma} {sub g} {sup +}, and X {sup 1}{Sigma}{sup +} {sub g} {yields}more » B {sup 1}{Sigma} {sub u} {sup +} excitation cross sections are employed in order to obtain the electronic excitation rate coefficients of H{sub 2} as functions of the spectral index and temperature. In low-temperature regions, it is found that the excitation rate coefficients R{sub b{sup 3}{Sigma}{sub u{sup {sub +}}}}, R{sub a{sup 3}{Sigma}{sub g{sup {sub +}}}}, and R{sub B{sub {sup 1}{Sigma}{sub u{sup {sub +}}}}} of H{sub 2} in non-Maxwellian plasmas are smaller than those in Maxwellian plasmas. However, in high-temperature regions, the excitation rate coefficients of H{sub 2} in non-Maxwellian plasmas are greater than those in Maxwellian plasmas. It is also shown that the X {sup 1}{Sigma}{sup +} {sub g} {yields} b {sup 3}{Sigma} {sub u} {sup +} excitation rate coefficient is the main contributor in low-temperature regions. In contrast, it is found that the X {sup 1}{Sigma}{sup +} {sub g} {yields} B {sup 1}{Sigma} {sub u} {sup +} electronic excitation is dominant in high-temperature regions.« less

Investigating the local structure of B-site cations in (1-x)BaTiO3-xBiScO3 and (1-x)PbTiO3-xBiScO3 using X-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Blanchard, Peter E. R.; Grosvenor, Andrew P.

2018-05-01

The structural properties of (1-x)BaTiO3-xBiScO3 and (1-x)PbTiO3-xBiScO3 were investigated using powder X-ray diffraction and X-ray absorption spectroscopy. Diffraction measurements confirmed that substituting small amounts of BiScO3 into BaTiO3 initially stabilizes a cubic phase at x = 0.2 before impurity phases begin to form at x = 0.5. BiScO3 substitution also resulted in noticeable changes in the local coordination environment of Ti4+. X-ray absorption near-edge spectroscopy (XANES) analysis showed that replacing Ti4+ with Sc3+ results in an increase in the off-centre displacement of Ti4+ cations. Surprisingly, BiScO3 substitution has no effect on the displacement of the Ti4+ cation in the (1-x)PbTiO3-xBiScO3 solid solution.

The standards process: Technical committee X3B5 digital magnetic tape

NASA Technical Reports Server (NTRS)

Cheatham, Sam

1993-01-01

The definition of X3B5, where it fits in the national and international standards development process, and how it interfaces and influences the world community of standards developers are provided. Details concerning the focus of the committee, how it operates, and what the group sees as the future trends in the area of interchange standards utilizing the multifaceted, ubiquitous magnetic tape are presented.

Facile synthesis of ZnFe2O4 photocatalysts for decolourization of organic dyes under solar irradiation

PubMed Central

Behera, Arjun; Kandi, Debasmita; Majhi, Sanjit Manohar

2018-01-01

ZnFe2O4 was fabricated by a simple solution-combustion method. The structural, optical and electronic properties are investigated by XRD, TEM, FESEM, UV–vis DRS, PL, FTIR and photocurrent measurements. The photocatalytic activity of the prepared material is studied with regard to the degradation of rhodamine B (Rh B) and Congo red under solar irradiation. The kinetic study showed that the material exhibits zeroth and first order reaction kinetics for the degradation of Rh B and Congo red, respectively. The photocatalytic behaviour of ZnFe2O4 was systematically studied as a function of the activation temperature. ZnFe2O4 prepared at 500 °C showed the highest activity in degrading Rh B and Congo red. The highest activity of ZnFe2O4-500 °C correlates well with the lowest PL intensity, highest photocurrent and lowest particle size. PMID:29515956

Red Light-Emitting Diode Based on Blue InGaN Chip with CdTe x S(1 - x) Quantum Dots

NASA Astrophysics Data System (ADS)

Wang, Rongfang; Wei, Xingming; Qin, Liqin; Luo, Zhihui; Liang, Chunjie; Tan, Guohang

2017-01-01

Thioglycolic acid-capped CdTe x S(1 - x) quantum dots (QDs) were synthesized through a one-step approach in an aqueous medium. The CdTe x S(1 - x) QDs played the role of a color conversion center. The structural and luminescent properties of the obtained CdTe x S(1 - x) QDs were investigated. The fabricated red light-emitting hybrid device with the CdTe x S(1 - x) QDs as the phosphor and a blue InGaN chip as the excitation source showed a good luminance. The Commission Internationale de L'Eclairage coordinates of the light-emitting diode (LED) at (0.66, 0.29) demonstrated a red LED. Results showed that CdTe x S(1 - x) QDs can be excited by blue or near-UV regions. This feature presents CdTe x S(1 - x) QDs with an advantage over wavelength converters for LEDs.

Photoluminescence Properties of Ca3Si2O7: Pr3+ Orange-Red Phosphors Prepared by High-Temperature Solid-State Method

NASA Astrophysics Data System (ADS)

Peng, Zhi-Qing; Chen, Rong; Feng, Wen-Lin

2018-06-01

Novel luminescent materials Ca3-xSi2O7: xPr3+ were successfully prepared by the high-temperature solid-state method. The crystal structure, morphology, and optical spectrum were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectroscopy, respectively. The XRD patterns of the samples indicate that the crystal structure is monoclinic symmetry. The SEM shows that the selected sample has good crystallinity although its appearance is irregular and scalelike. The peak of the excitation spectrum of the sample is located at around 449 nm, corresponding to 3H4→3P2 transition of Pr3+. The peak of the emission spectrum of the sample is situated at around 612 nm which is attributed to 3P0→3H6 transition of Pr3+, and the colour is orange-red. The optimum concentration for Pr3+ replaced Ca2+ sites in Ca3Si2O7: Pr3+ is 0.75 mol%. The lifetime (8.48 μs) of a typical sample (Ca2.9925Pr0.0075)Si2O7 is obtained. It reveals that orange-red phosphors Ca3-xSi2O7: xPr3+ possess remarkable optical properties and can be used in white light emitting devices.

Preparation, characterization and luminescence properties of a new hydrous red phosphor CaB3 O5 (OH):Eu3+ with different morphologies.

PubMed

Huang, H S; Tang, A J; Yang, C; Jin, H F

2017-03-01

A new borate phosphor CaB 3 O 5 (OH):Eu 3 + with different morphologies was synthesized using a hydrothermal method and its luminescence properties were studied. The effects of surfactants on the crystal structures, morphologies and luminescence properties of the samples were studied. The results showed that the surfactants play an important role in controlling the morphology and improving the luminescence properties of phosphors. The luminescence intensity and R/O(I615/I592) value were enhanced for the prepared sample by adding PEG4000. The prepared sample exhibited a higher R/O than some anhydrous calcium borate phosphors, indicating that this product could serve as a new potential red phosphor. Copyright © 2016 John Wiley & Sons, Ltd.

Acute Arthritis in Crimean-Congo Hemorrhagic Fever

PubMed Central

Ahmeti, Salih; Ajazaj-Berisha, Lindita; Halili, Bahrije; Shala, Anita

2014-01-01

Crimean-Congo hemorrhagic fever is a severe viral disease caused by a Nairovirus. An atypical manifestation in the form of acute arthritis was found in a confirmed Crimean-Congo hemorrhagic fever virus Kosova-Hoti strain positive patient. Acute arthritis in Crimean-Congo hemorrhagic fever (CCHF) may be as a result of immune mechanisms or the bleeding disorder underlying CCHF. PMID:24926169

Red-emitting LaOF:Eu{sup 3+} phosphors: Synthesis, structure and their Judd–Ofelt analysis for LED applications

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

Dhananjaya, N., E-mail: ndhananjayas@gmail.com; Shivakumara, C.; Saraf, Rohit

Highlights: • Red-emitting LaOF:Eu{sup 3+} phosphors were synthesized via facile solid state route. • Judd–Ofelt intensity parameters and radiative properties were determined from PL data. • CIE color coordinates of LaOF:Eu{sup 3+} phosphor is close to the commercial red phosphors. • Eu{sup 3+}-activated LaOF phosphor is a potential candidate for the production of red component in white LEDs. - Abstract: In the present study, we have synthesized a series of La{sub 1−x}Eu{sub x}OF (0.01 ≤ x ≤ 0.09) phosphors by the conventional solid-state reaction route at relatively low temperature (500 °C) and shorter duration of 2 h. The compounds weremore » crystallized in the rhombohedral structure with the space group R-3m (No. 166). Upon UV excitation (254 nm), the photoluminescence spectra exhibit characteristic luminescence {sup 5}D{sub 0} → {sup 7}F{sub J} (J = 1, 2, 3, and 4) intra-4f shell Eu{sup 3+} ion transitions. An intense red emission peak at 610 nm was observed due to electric dipole ({sup 5}D{sub 0} → {sup 7}F{sub 2}) transition. Judd–Ofelt theory was employed to evaluate various radiative parameters such as radiative emission rates, lifetime, branching and asymmetry ratios. CIE color coordinates confirmed the red emission of the phosphors. The luminescent results reveal that LaOF:Eu{sup 3+} phosphor can be used as potential candidate for developing red component in white LED applications.« less

High-redshift Extremely Red Quasars in X-Rays

NASA Astrophysics Data System (ADS)

Goulding, Andy D.; Zakamska, Nadia L.; Alexandroff, Rachael M.; Assef, Roberto J.; Banerji, Manda; Hamann, Fred; Wylezalek, Dominika; Brandt, William N.; Greene, Jenny E.; Lansbury, George B.; Pâris, Isabelle; Richards, Gordon; Stern, Daniel; Strauss, Michael A.

2018-03-01

Quasars may have played a key role in limiting the stellar mass of massive galaxies. Identifying those quasars in the process of removing star formation fuel from their hosts is an exciting ongoing challenge in extragalactic astronomy. In this paper, we present X-ray observations of 11 extremely red quasars (ERQs) with L bol ∼ 1047 erg s‑1 at z = 1.5–3.2 with evidence for high-velocity (v ≥slant 1000 km s‑1) [O III] λ5007 outflows. X-rays allow us to directly probe circumnuclear obscuration and to measure the instantaneous accretion luminosity. We detect 10 out of 11 ERQs available in targeted and archival data. Using a combination of X-ray spectral fitting and hardness ratios, we find that all of the ERQs show signs of absorption in the X-rays with inferred column densities of N H ≈ 1023 cm‑2, including four Compton-thick candidates (N H ≥slant 1024 cm‑2). We stack the X-ray emission of the seven weakly detected sources, measuring an average column density of N H ∼ 8 × 1023 cm‑2. The absorption-corrected (intrinsic) 2–10 keV X-ray luminosity of the stack is 2.7 × 1045 erg s‑1, consistent with X-ray luminosities of type 1 quasars of the same infrared luminosity. Thus, we find that ERQs are a highly obscured, borderline Compton-thick population, and based on optical and infrared data we suggest that these objects are partially hidden by their own equatorial outflows. However, unlike some quasars with known outflows, ERQs do not appear to be intrinsically underluminous in X-rays for their bolometric luminosity. Our observations indicate that low X-rays are not necessary to enable some types of radiatively driven winds.

Crimean-Congo Hemorrhagic Fever Virus in Pakistan.

PubMed

Ijaz, Muhammad; Rahim, Afaq; Ali, Iftikhar

2017-01-01

The Crimean-Congo hemorrhagic fever is a zoonotic disease transmitted by ticks and is characterized by fever and bleeding. It was seen for the first time in the south of present day Ukraine and thus named, Crimean fever. 1 In 1956, the virus was isolated in a patient with similar symptoms residing in Congo, Kenya and the virus was named Congo virus. The viruses causing these two diseases were the same and hence was termed Crimean-Congo hemorrhagic fever virus (CCHFV). Humans are the only known host that develops disease. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Performance and mechanism of simultaneous removal of Cd(II) and Congo red from aqueous solution by hierarchical vaterite spherulites

NASA Astrophysics Data System (ADS)

Chen, Yuan-Yuan; Yu, Sheng-Hui; Jiang, Hao-Fan; Yao, Qi-Zhi; Fu, Sheng-Quan; Zhou, Gen-Tao

2018-06-01

Hierarchical vaterite spherulites, synthesized by a simple injection-precipitation method at room temperature, were applied for the simultaneous removal of heavy metal Cd(II) and dye Congo red (CR) from aqueous solution. Batch experiments reveal that the maximum removal capacities of as-prepared vaterite spherulites to Cd(II) and CR are 984.5 and 89.0 mg/g, respectively, showing excellent removal performance for Cd(II) and CR. Furthermore, in the binary Cd(II)-CR system, the removal capacity of vaterite to Cd(II) is significantly enhanced at lower CR concentration (<100 mg/L), but inhibited at higher CR concentration (>100 mg/L). In contrast, the concurrent Cd(II) shows negligible effect on the CR removal. The simultaneous removal mechanism was investigated by FESEM, EDX, XRD, FT-IR and XPS techniques. The simultaneous removal of Cd(II) and CR in the binary system is shown to be a multistep process, involving the preferential adsorption of dye CR, stabilization of CR to vaterite, coordination of the adsorbed CR molecules with Cd(II), and transformation of vaterite into otavite. Given the facile and green synthesis procedure, and effective removal of Cd(II) and CR in the binary system, the obtained vaterite spherulites have considerable practical interest in integrative treatment of wastewater contaminated by heavy metals and dyes.

LIVING WITH A RED DWARF: ROTATION AND X-RAY AND ULTRAVIOLET PROPERTIES OF THE HALO POPULATION KAPTEYN’S STAR

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

Guinan, Edward F.; Engle, Scott G.; Durbin, Allyn, E-mail: scott.engle@villanova.edu

As part of Villanova’s Living with a Red Dwarf program, we have obtained UV, X-ray, and optical data of the Population II red dwarf—Kapteyn’s Star. Kapteyn’s Star is noteworthy for its large proper motions and high radial velocity of ∼+245 km s{sup −1}. As the nearest Pop II red dwarf, it serves as an old age anchor for calibrating activity/irradiance–rotation–age relations, and an important test bed for stellar dynamos and the resulting X-ray–UV emissions of slowly rotating, near-fully convective red dwarf stars. Adding to the notoriety, Kapteyn’s Star has recently been reported to host two super-Earth candidates, one of whichmore » (Kapteyn b) is orbiting within the habitable zone. However, Robertson et al. questioned the planet’s existence since its orbital period may be an artifact of activity, related to the star’s rotation period. Because of its large Doppler-shift, measures of the important, chromospheric H i Lyα 1215.67 Å emission line can be reliably made, because it is mostly displaced from ISM and geo-coronal sources. Lyα emission dominates the FUV region of cool stars. Our measures can help determine the X-ray–UV effects on planets hosted by Kapteyn’s Star, and planets hosted by other old red dwarfs. Stellar X-ray and Lyα emissions have strong influences on the heating and ionization of upper planetary atmospheres and can (with stellar winds and flares) erode or even eliminate planetary atmospheres. Using our program stars, we have reconstructed the past exposures of Kapteyn’s Star's planets to coronal—chromospheric XUV emissions over time.« less

MgB2-Based Bolometer Array for Far Infra-Red Thermal Imaging and Fourier Transform Spectroscopy Applications

NASA Technical Reports Server (NTRS)

Lakew, B.; Aslam, S.; Brasunas, J.

2012-01-01

The mid-superconducting critical temperature (T(sub c) approximately 39 K) of the simple binary, intermetallic MgB, [1] makes it a very good candidate for the development of the next generation of electrooptical devices (e.g. [2]). In particular, recent advances in thin film deposition teclmiques to attain higb quality polycrystalline thin film MgB, deposited on SiN-Si substrates, with T(sub c) approximately 38K [3] coupled with the low voltage noise performance of the film [4] makes it higbly desirable for the development of moderately cooled bolometer arrays for integration into future space-bourne far infra-red (FIR) spectrometers and thermal mappers for studying the outer planets, their icy moons and other moons of interest in the 17-250 micrometer spectral wavelength range. Presently, commercially available pyroelectric detectors operating at 300 K have specific detectivity, D(*), around 7 x 10(exp 8) to 2 x 10(exp 9) centimeters square root of Hz/W. However, a MgB2 thin film based bolometer using a low-stress (less than 140 MPa) SiN membrane isolated from the substrate by a small thermal conductive link, operating at 38 K, promises to have two orders of magnitude higher specific detectivity [5][6].

Development of sustainable dye adsorption system using nutraceutical industrial fennel seed spent-studies using Congo red dye.

PubMed

Taqui, Syed Noeman; Yahya, Rosiyah; Hassan, Aziz; Nayak, Nayan; Syed, Akheel Ahmed

2017-07-03

Fennel seed spent (FSS)-an inexpensive nutraceutical industrial spent has been used as an efficient biosorbent for the removal of Congo red (CR) from aqueous media. Results show that the conditions for maximum adsorption would be pH 2-4 and 30°C were ideal for maximum adsorption. Based on regression fitting of the data, it was determined that the Sips isotherm (R 2 = 0.994, χ 2 = 0.5) adequately described the mechanism of adsorption, suggesting that the adsorption occurs homogeneously with favorable interaction between layers with favorable interaction between layers. Thermodynamic analysis showed that the adsorption is favorable (negative values for ΔG°) and endothermic (ΔH° = 12-20 kJ mol -1 ) for initial dye concentrations of 25, 50, and 100 ppm. The low ΔH° value indicates that the adsorption is a physical process involving weak chemical interactions like hydrogen bonds and van der Waals interactions. The kinetics revealed that the adsorption process showed pseudo-second-order tendencies with the equal influence of intraparticle as well as film diffusion. The scanning electron microscopy images of FSS show a highly fibrous matrix with a hierarchical porous structure. The Fourier transform infrared spectroscopy analysis of the spent confirmed the presence of cellulosic and lignocellulosic matter, giving it both hydrophilic and hydrophobic properties. The investigations indicate that FSS is a cost-effective and efficient biosorbent for the remediation of toxic CR dye.

Identification of diverse Bartonella genotypes among small mammals from Democratic Republic of Congo and Tanzania.

PubMed

Gundi, Vijay A K B; Kosoy, Michael Y; Makundi, Rhodes H; Laudisoit, Anne

2012-08-01

Small mammals from the Democratic Republic (DR) of the Congo and Tanzania were tested to determine the prevalence and genetic diversity of Bartonella species. The presence of Bartonella DNA was assessed in spleen samples of the animals by rpoB- and gltA-polymerase chain reactions (PCRs). By rpoB-PCR, Bartonella was detected in 8 of 59 animals of DR Congo and in 16 of 39 Tanzanian animals. By gltA-PCR, Bartonella was detected in 5 and 15 animals of DR Congo and Tanzania, respectively. The gene sequences from Arvicanthis neumanni were closely related to Bartonella elizabethae. The genotypes from Lophuromys spp. and from Praomys delectorum were close to Bartonella tribocorum. Five genogroups were not genetically related to any known Bartonella species. These results suggest the need to conduct further studies to establish the zoonotic risks linked with those Bartonella species and, in particular, to verify whether these agents might be responsible for human cases of febrile illness of unknown etiology in Africa.

Central African Security: Conflict in the Congo

DTIC Science & Technology

2002-01-01

strategically important Democratic Republic of the Congo (DRC). We were indeed fortunate to have as authors presenters Dr. Crawford Young, Dr. Herb...of this situation is essential for intelligence analysts and for policymakers trying to define and protect U.S. interests in the region. Importance of...DRC The Democratic Republic of the Congo, formerly known as Zaire and the Belgian Congo, has long been one of the most strategically important

Remarkably Enhancing Green-Excitation Efficiency for Solar Energy Utilization: Red Phosphors Ba2ZnS3:Eu2+, X- Co-Doped Halide Ions (X = Cl, Br, I).

PubMed

Luo, Tingting; Du, Yun; Qiu, Zhongxian; Li, Yanmei; Wang, Xiaofang; Zhou, Wenli; Zhang, Jilin; Yu, Liping; Lian, Shixun

2017-05-15

Eu 2+ -activated Ba 2 ZnS 3 has been reported as a red phosphor with a broad emission band peaking at 650 nm under blue excitation for white-LED. In this study, Ba 2 ZnS 3 :Eu 2+ , X - (X = F, Cl, Br, I) phosphors doped with halide ions were prepared by traditional high-temperature solid-state reaction. Phase identification of powders was performed by X-ray powder diffraction analysis, confirming the existence of single-phase Ba 2 ZnS 3 crystals without dopant. The corresponding excitation spectra showed an additional broad band in the green region peaking at 550 nm when the phosphor was halogenated except by the smallest F - . It was proved that the green-excitation efficiency successively strengthened from Cl - , to Br - , to I - , which suggested larger halide ions made a greater contribution to the further splitting of the t 2g energy level of the doped Eu 2+ ions in the host Ba 2 ZnS 3 , and the optimized formula Ba 1.995 ZnS 2.82 :Eu 2+ 0.005 , I - 0.18 showed a potential application in solar spectral conversion for agricultural greenhouse and solar cell. Defect chemistry theory and crystal field theory provided insights into the key role of halide ions in enhancing green-excitation efficiency.

Fragile morphotropic phase boundary and phase stability in the near-surface region of the relaxor ferroelectric (1 -x ) Pb (Z n1 /3N b2 /3) O3-x PbTi O3 : [001] field-cooled phase diagrams

NASA Astrophysics Data System (ADS)

Wang, Yaojin; Wang, Ding; Yuan, Guoliang; Ma, He; Xu, Feng; Li, Jiefang; Viehland, D.; Gehring, Peter M.

2016-11-01

We have examined the effects of field cooling on the phase diagram of the relaxor system (1 -x ) Pb (Z n1 /3N b2 /3) O3-x PbTi O3 (PZN-x PT ) for compositions near the morphotropic phase boundary (MPB). High-resolution diffraction measurements using Cu Kα x rays, which probe ≈3 μ m below the crystal surface, were made on field-cooled (FC) single-crystal specimens of PZN-4.5 %PT and PZN-6.5 %PT under electric fields of 1 and 2 kV/cm applied along [001] and combined with previous neutron diffraction data, which probe the entire crystal volume, for FC PZN-8 %PT [Ohwada et al., Phys. Rev. B 67, 094111 (2003), 10.1103/PhysRevB.67.094111]. A comparison to the zero-field-cooled (ZFC) PZN-x PT phase diagram reveals several interesting features: (1) The short-range monoclinic phase observed in the ZFC state on the low-PT side of the MPB is replaced by a monoclinic MA phase; (2) field cooling extends the tetragonal phase to higher temperatures and lower-PT concentrations; (3) the orthorhombic phase near the MPB is replaced by a monoclinic MC phase; (4) the vertical MPB in the ZFC phase diagram bends significantly towards the low-PT side in the FC state. These results demonstrate that both the phase stability and the nature of the MPB in PZN-PT within the near-surface regions are fragile in the presence of electric fields.

Sol-gel syntheses of pentaborate β-LaB5O9 and the photoluminescence by doping with Eu3+, Tb3+, Ce3+, Sm3+, and Dy3+

NASA Astrophysics Data System (ADS)

Yang, Ruirui; Sun, Xiaorui; Jiang, Pengfei; Gao, Wenliang; Cong, Rihong; Yang, Tao

2018-02-01

Rare earth (RE) borates have been extensively studied as good photoluminescent materials, however, the target hosts were limited to "RE3BO6", REBO3, and REB3O6 in the RE2O3-B2O3 phase diagram until the recent discovery of rare earth pentaborate. For the first time, the sol-gel method was employed to synthesize β-LaB5O9 doped with Eu3+, Tb3+, Ce3+, Sm3+, Dy3+. In comparison to the previous synthetic methods, the sol-gel method possesses superiorities including easily-controllable doping concentration, high yield and emission efficiency. Solid solutions of phosphors were prepared and carefully analyzed by powder X-ray diffraction. Concentration quenching or saturation was observed in Eu3+, Tb3+ and Ce3+ doped phosphors at round 10 at%. Eu3+, Tb3+, Sm3+, and Dy3+ emit red, green, orange, and close-to-white light, respectively. The absolute emission efficiency of Ce3+ is high and in the UV range, suggesting the function of being sensitizer once combined with other activators.

Opportunities for Hydrologic Research in the Congo Basin

NASA Astrophysics Data System (ADS)

Alsdorf, D. E.; Beighley, E., II; Lee, H.; Tshimanga, R.; Spencer, R. G.; O'Loughlin, F.

2014-12-01

We review the published results on the Congo Basin hydrology and find that there are historic data, ongoing measurement recording efforts, and important model results. Annual rainfall is ~2000 mm/yr along an east-west trend, decreasing northward and southward to ~1100 mm/yr. While some studies show rain gauges at specific locations with declines in P greater than 10% from 1960 to 1990, other studies suggest that basin wide decreases from 1951 to 1993 are modest at 4.5% or that the trend is minimal. Studies during the 1950s using lysimeters, pans, and models suggest that the annual potential ET varies little across the basin at a 1100 mm/yr to 1200 mm/yr. Over the past century, river discharge data has been collected at 100s of stream gauges with historic and recent data at 96 locations now publicly available. Discharge of the Congo River at Kinshasa-Brazzaville experienced an increase of 21% during 1960-1970 in comparison to background values of the previous decades and of today. There does not appear to be a long-term discharge trend over the century of record. Satellite altimetry measurements collected during high and low flows show that the Cuvette Centrale wetland water levels are consistently 0.5m to 3m higher in elevation than the immediately adjacent Congo River levels. Wetland water depths are shallow at about 1m whereas the Congo is typically less than 15m deep everywhere upstream of Kinshasa. The wetlands do not appear to be marked by sizable channels such that the flows are diffusive. CO2 and CH4 evasion from the Congo waters directly to the atmosphere are estimated at 1.6 to 3.2 Tg/yr for CH4 from the Cuvette wetland waters and 105 to 204 g C/m2/yr for CO2 from waters of the Oubangui River. Using these published results, we suggest seven hypotheses that may lead to important water and carbon cycle discoveries. These hypotheses focus on the source of the Cuvette waters and how those waters leave the wetland; on river discharge generated by historic

Wind-Tunnel Results of the B-52B with the X-43A Stack

NASA Technical Reports Server (NTRS)

Davis, Mark C.; Sim, Alexander G.; Rhode, Matthew; Johnson, Kevin D., Sr.

2007-01-01

A low-speed wind-tunnel test was performed with a 3%-scale model of a booster rocket mated to an X-43A research vehicle, a combination referred to as the Hyper-X launch vehicle. The test was conducted both in freestream air and in the presence of a partial model of the B-52B airplane. The objectives of the test were to obtain force and moment data to generate structural loads affecting the pylon of the B-52B airplane and to determine the aerodynamic influence of the B-52B on the Hyper-X launch vehicle for evaluating launch separation characteristics. The windtunnel test was conducted at a low-speed wind tunnel in Hampton, Virginia. All moments and forces reported are based either on the aerodynamic influence of the B-52B airplane or are for the Hyper-X launch vehicle in freestream air. Overall, the test showed that the B-52B airplane imparts a strong downwash onto the Hyper-X launch vehicle, reducing the net lift of the Hyper-X launch vehicle. Pitching and rolling moments are also imparted onto the booster and are a strong function of the launch-drop angle of attack.

A computational study of hydrogen-bonded X3CH⋯YZ (X = Cl, F, NC; YZ = FLi, BF, CO, N2) complexes

NASA Astrophysics Data System (ADS)

McDowell, Sean A. C.

2018-03-01

An MP2/6-311++G(3df,3pd) computational study of a series of hydrogen-bonded complexes X3CH⋯YZ (X = Cl, F, NC; YZ = FLi, BF, CO, N2) was undertaken to assess the trends in the relative stability and other molecular properties with variation of both the X group and the chemical hardness of the Y atom of YZ. The red- and blue-shifting propensities of the proton donor X3CH were investigated by considering the Csbnd H bond length change and its associated vibrational frequency shift. The proton donor Cl3CH, which has a positive dipole moment derivative with respect to Csbnd H bond extension, tends to form red-shifted complexes, this tendency being modified by the hardness (and dipole moment) associated with the proton acceptor. On the other hand, F3CH has a negative dipole moment derivative and tends to form blue-shifted complexes, suggesting that as X becomes more electron-withdrawing, the proton donor should have a negative dipole moment derivative and form blue-shifted complexes. Surprisingly, the most polar proton donor (NC)3CH was found to have a positive dipole moment derivative and produces red-shifted complexes. A perturbative model was found useful in rationalizing the trends for the Csbnd H bond length change and associated frequency shift.

Novel protein–inhibitor interactions in site 3 of Ca2+-bound S100B as discovered by X-ray crystallography

PubMed Central

Cavalier, Michael C.; Melville, Zephan; Aligholizadeh, Ehson; Raman, E. Prabhu; Yu, Wenbo; Fang, Lei; Alasady, Milad; Pierce, Adam D.; Wilder, Paul T.; MacKerell, Alexander D.; Weber, David J.

2016-01-01

Structure-based drug discovery is under way to identify and develop small-molecule S100B inhibitors (SBiXs). Such inhibitors have therapeutic potential for treating malignant melanoma, since high levels of S100B downregulate wild-type p53 tumor suppressor function in this cancer. Computational and X-ray crystallographic studies of two S100B–SBiX complexes are described, and both compounds (apomorphine hydrochloride and ethidium bromide) occupy an area of the S100B hydrophobic cleft which is termed site 3. These data also reveal novel protein–inhibitor interactions which can be used in future drug-design studies to improve SBiX affinity and specificity. Of particular interest, apomorphine hydrochloride showed S100B-dependent killing in melanoma cell assays, although the efficacy exceeds its affinity for S100B and implicates possible off-target contributions. Because there are no structural data available for compounds occupying site 3 alone, these studies contribute towards the structure-based approach to targeting S100B by including interactions with residues in site 3 of S100B. PMID:27303795

Complete titanium substitution by boron in a tetragonal prism: exploring the complex boride series Ti(3-x)Ru(5-y)Ir(y)B(2+x) (0 ≤ x ≤ 1 and 1 < y < 3) by experiment and theory.

PubMed

Fokwa, Boniface P T; Hermus, Martin

2011-04-18

Polycrystalline samples and single crystals of four members of the new complex boride series Ti(3-x)Ru(5-y)Ir(y)B(2+x) (0 ≤ x ≤ 1 and 1 < y < 3) were synthesized by arc-melting the elements in a water-cooled copper crucible under an argon atmosphere. The new silvery phases were structurally characterized by powder and single-crystal X-ray diffraction as well as energy- and wavelength-dispersive X-ray spectroscopy analyses. They crystallize with the tetragonal Ti(3)Co(5)B(2) structure type in space group P4/mbm (No. 127). Tetragonal prisms of Ru/Ir atoms are filled with titanium in the boron-poorest phase (Ti(3)Ru(2.9)Ir(2.1)B(2)). Gradual substitution of titanium by boron then results in the successive filling of this site by a Ti/B mixture en route to the complete boron occupation, leading to the boron-richest phase (Ti(2)Ru(2.8)Ir(2.2)B(3)). Furthermore, both ruthenium and iridium share two sites in these structures, but a clear Ru/Ir site preference is found. First-principles density functional theory calculations (Vienna ab initio simulation package) on appropriate structural models (using a supercell approach) have provided more evidence on the stability of the boron-richest and -poorest phases, and the calculated lattice parameters corroborate very well with the experimentally found ones. Linear muffin-tin orbital atomic sphere approximation calculations further supported these findings through crystal orbital Hamilton population bonding analyses, which also show that the Ru/Ir-B and Ru/Ir-Ti heteroatomic interactions are mainly responsible for the structural stability of these compounds. Furthermore, some stable and unstable phases of this complex series could be predicted using the rigid-band model. According to the density of states analyses, all phases should be metallic conductors, as was expected from these metal-rich borides.

Sea Surface Salinity Variability in Response to the Congo River Discharge

NASA Astrophysics Data System (ADS)

Moller, D.; Chao, Y.; Farrara, J. D.; Schumann, G.; Andreadis, K.

2014-12-01

Sea surface salinity (SSS) variability associated with the Congo River discharge is examined using Aquarius satellite-retrieved SSS data and vertical profiles of salinity measured by the Argo floats. The Congo River plume can be clearly identified in the Aquarius SSS data with a westward extension of 500 to 1000 km off the coast of the Democratic Republic of Congo (DRC). The peak amplitude of the SSS variability associated with the Congo River discharge exceeds 2.0 psu. Using the first two years of Aquarius data, a well-defined seasonal cycle is described: maximum fresh-water anomalies are found in the boreal winter and spring seasons. The fresh-water anomalies during the 2012-2013 winter and spring seasons are significantly fresher than the 2011-2012 winter and spring seasons. Vertical profiles of salinity derived from the Argo floats reveal that these fresh-water anomalies can be traced to 40 meters below the sea surface. Combining the Aquarius SSS data with the Argo vertical profiles of salinity, the 3D volume of these fresh-water anomalies can be inferred and used to estimate the Congo River discharge. Reasonably good agreement is found between the Congo River discharge as observed by a stream gauge at Kinshasa and that estimated from the combined Aquarius and Argo data, indicating that Aquarius data can be used to close the fresh-water budget between the coastal ocean and the Congo River. The precipitation minus evaporation portion of the freshwater flux is found to play a secondary role in this region.

A new Keggin-type polyoxometalate catalyst for degradation of aqueous organic contaminants

NASA Astrophysics Data System (ADS)

Olgun, Asim; Çolak, Alper Tolga; Gübbük, İ. Hilal; Şahin, Onur; Kanar, Ebru

2017-04-01

In this study, a new polyoxometalate, K16[Ni(H2O)6]2[BW12O40]4·48H2O (1) was synthesized at room temperature and characterized by X-ray single crystal diffractions, elemental analyses, IR spectra, and thermo gravimetric analyses (TGA). Crystal structure analysis reveals that compound 1 exhibits a supramolecular structure containing one Keggin-type [BW12O40]4 heteropoly anion. The catalytic properties of this molecule for the degradation of Methyl red (MR), Rhodamine B (RhB), Methyl orange (MO) and Congo red (CR) were investigated. The results show that the compound 1 is a promising catalyst candidate for dye degradation.

The melting of native domain structure in effector activation of IgG studied by using congo red as a specific probe.

PubMed

Piekarska, B; Roterman, I; Rybarska, J; Koniczny, L; Kaszuba, J

1994-03-01

The nature of structural changes in IgG molecules associated with the binding to antigen and/or heat aggregation was studied using bis azo dye (Congo Red) as the specific probe. It was found, that protein conformation responsible for binding the dye represents an unfolding intermediate with properties corresponding to a molten globule state. The properties of the dye-protein complex reveal the signs of an unfolding of the peptide chain with simultaneously preserved relatively compact packing. Immunoglobulins which were induced by heating, or binding to antigen in order to form the complex with dye ligands, become more susceptible for digestion. The main peptide of molecular weight 30,000 D which appears in products was suggested to originate from a heavy chain after its splitting in the region of CH1 domain. The energetic evaluation of stability of IgG domains also indicates that CH1 is the least stable fragment of the heavy chain and its conformation may be destabilized first. It was concluded that destabilized tertiary packing of antibodies bound to antigen may favour the association of closely situated immunoglobulin molecules increasing the stability of the immune complex and influencing in the result its effector activity.

Why do we see Broad Lines in X-ray Absorbed, Red AGN?

NASA Astrophysics Data System (ADS)

Wilkes, B. J.; Ghosh, Himel; Cutri, R.; Hines, D.; Nelson, B.; Schmidt, G. D.; Smith, P. S.

2003-05-01

The Two Micron All-Sky Survey (2MASS) red AGN catalog has revealed a previously unknown population whose number density rivals that of optically-selected AGN as found in the many, relatively shallow surveys (e.g. PG, Hamburg). The Chandra X-ray spectra of these red, mostly broad-line AGN are hard. This, combined with their unusually high optical polarization, suggests substantial obscuration (log NH = 21-23 cm-2) toward the nuclear energy source, despite a clear view of the broad emission line region. We have expanded our Chandra-observed sub-sample to include 20 more 2MASS AGN yielding a set of 46 which includes all available optical classes. This sample is thus pre-selected for complex absorption and sufficient to study the relative X-ray and optical obscuration for each AGN class. Those observed to date continue the lack of a relation between the X-ray hardness ratio and optical class noted in our earlier sample. Combining this with X-ray spectral fits where we have sufficient counts and with our multi-wavelength data, we compare the spectral energy distributions with those of normal and other red AGN and investigate possible scenarios for the absorbing material. We gratefully ackowledge the financial support of NASA grant: GO1-2112A

The synthesis and luminescence properties of a novel red-emitting phosphor: Eu3+-doped Ca9La(PO4)7

NASA Astrophysics Data System (ADS)

Liang, Zehui; Mu, Zhongfei; Wang, Qiang; Zhu, Daoyun; Wu, Fugen

2017-10-01

A series of novel red-emitting phosphors Ca9La1- x (PO4)7: xEu3+ were synthesized by high-temperature solid state reactions. The photoluminescence excitation and photoluminescence spectra of these phosphors were investigated in detail. O2--Eu3+ charge transfer band peaking at about 261 nm is dominant in the PLE spectra of Eu3+-doped Ca9La(PO4)7, indicating that the phosphors are suitable for tricolor fluorescent lamps. The phosphors also show a good absorption in near ultraviolet (around 395 nm) and blue (around 465 nm) spectral region, which indicates that it can be pumped with NUV and blue chips for white light-emitting diodes. The transition of 5D0 → 7F2 of Eu3+ in this lattice can emit bright red light. Ca9La(PO4)7 could accommodate a large amount of Eu3+ with an optimal concentration of 60 mol%. The dipole-dipole interaction between Eu3+ is the dominant mechanism for concentration quenching of Eu3+. The calculated color coordinates lie in red region ( x = 0.64, y = 0.36), which is close to Y2O3: 0.05Eu3+ ( x = 0.65, y = 0.34). The integral emission intensity of Ca9La0.4(PO4)7: 0.6Eu3+ is 1.9 times stronger than that of widely used commercial red phosphor Y2O3: 0.05Eu3+. All these results indicate that Eu3+-doped Ca9La(PO4)7 is a promising red-emitting phosphor which can be used in tricolor fluorescent lamps and white light-emitting diodes.

Trace metal distributions in the sediments from river-reservoir systems: case of the Congo River and Lake Ma Vallée, Kinshasa (Democratic Republic of Congo).

PubMed

Mwanamoki, Paola M; Devarajan, Naresh; Niane, Birane; Ngelinkoto, Patience; Thevenon, Florian; Nlandu, José W; Mpiana, Pius T; Prabakar, Kandasamy; Mubedi, Josué I; Kabele, Christophe G; Wildi, Walter; Poté, John

2015-01-01

The contamination of drinking water resources by toxic metals is a major problem in many parts of the world, particularly in dense populated areas of developing countries that lack wastewater treatment facilities. The present study characterizes the recent evolution with time of some contaminants deposited in the Congo River and Lake Ma Vallée, both located in the vicinity of the large city of Kinshasa, capital of Democratic Republic of Congo (DRC). Physicochemical parameters including grain size distribution, organic matter and trace element concentrations were measured in sediment cores sampled from Congo River (n = 3) and Lake Ma Vallée (n = 2). The maximum concentration of trace elements in sediment profiles was found in the samples from the sites of Pool Malebo, with the values of 107.2, 111.7, 88.6, 39.3, 15.4, 6.1 and 4.7 mg kg(-1) for Cr, Ni, Zn, Cu, Pb, As and Hg, respectively. This site, which is characterized by intense human activities, is especially well known for the construction of numerous boats that are used for regular navigation on Congo River. Concerning Lake Ma Vallée, the concentration of all metals are generally low, with maximum values of 26.3, 53.6, 16.1, 15.3, 6.5 and 1.8 mg kg(-1) for Cr, Ni, Zn, Cu, Pb and As, respectively. However, the comparison of the metal profiles retrieved from the different sampled cores also reveals specific variations. The results of this study point out the sediment pollution by toxic metals in the Congo River Basin. This research presents useful tools for the evaluation of sediment contamination of river-reservoir systems.

CD19xCD3 DART protein mediates human B-cell depletion in vivo in humanized BLT mice

PubMed Central

Tsai, Perry; Thayer, William O; Liu, Liqin; Silvestri, Guido; Nordstrom, Jeffrey L; Garcia, J Victor

2016-01-01

Novel therapeutic strategies are needed for the treatment of hematologic malignancies; and bispecific antibody-derived molecules, such as dual-affinity re-targeting (DART) proteins, are being developed to redirect T cells to kill target cells expressing tumor or viral antigens. Here we present our findings of specific and systemic human B-cell depletion by a CD19xCD3 DART protein in humanized BLT mice. Administration of the CD19xCD3 DART protein resulted in a dramatic sustained depletion of human CD19+ B cells from the peripheral blood, as well as a dramatic systemic reduction of human CD19+ B-cell levels in all tissues (bone marrow, spleen, liver, lung) analyzed. When human CD8+ T cells were depleted from the mice, no significant B-cell depletion was observed in response to CD19xCD3 DART protein treatment, confirming that human CD8+ T cells are the primary effector cells in this in vivo model. These studies validate the use of BLT humanized mice for the in vivo evaluation and preclinical development of bispecific molecules that redirect human T cells to selectively deplete target cells. PMID:27119115

Novel tunable green-red-emitting oxynitride phosphors co-activated with Ce3+, Tb3+, and Eu3+: photoluminescence and energy transfer.

PubMed

Huo, Jiansheng; Dong, Langping; Lü, Wei; Shao, Baiqi; You, Hongpeng

2017-07-14

A series of novel Ce 3+ , Tb 3+ and Eu 3+ ion doped Y 4 SiAlO 8 N-based oxynitride phosphors were synthesized by the solid-state method and characterized by X-ray powder diffraction, scanning electron microscopy, photoluminescence, lifetimes and thermo-luminescence. The excitation of the Ce 3+ /Tb 3+ co-doped and Ce 3+ /Tb 3+ /Eu 3+ tri-doped phosphor with near-UV radiation results in strong linear Tb 3+ green and Eu 3+ red emission. The occurrence of Ce 3+ -Tb 3+ and Ce 3+ -Tb 3+ -Eu 3+ energy transfer processes is responsible for the bright green or red luminescence. The Tb 3+ ion acting as an energy transfer bridge can alleviate MMCT quenching between the Ce 3+ -Eu 3+ ion pairs. The lifetime measurements demonstrated that the energy-transfer mechanisms of Ce 3+ → Tb 3+ and Tb 3+ → Eu 3+ are dipole-quadrupole and quadrupole-quadrupole interactions, respectively. The temperature dependent luminescence measurements showed that as-prepared green/red phosphors have good thermal stability against temperature quenching. The obtained results indicate that these phosphors might serve as promising candidates for n-UV LEDs.

Understanding the hydrodynamics of the Congo River

NASA Astrophysics Data System (ADS)

O'Loughlin, Fiachra; Bates, Paul

2014-05-01

We present the results of the first hydrodynamic model of the middle reach of the Congo Basin, which helps our understanding of the behaviour of the second largest river in the world. In data sparse area, hydrodynamic models, utilizing a mixture of limited in-situ measurements and remotely sensed datasets, can be used to understand and identify key features that control large river systems. Unlike previous hydrodynamic models for the Congo Basin, which concentrated on only a small area, we look at the entire length of the Congo's middle reach and its six main tributaries (Kasai, Ubangai, Sangha, Ruki, Lulonga and Lomami). This corresponds to: a drainage area of approximately two and a half million kilometres squared; over 5000 kilometres of river channels; and incorporates some of the largest and most important global wetlands. The hydrodynamic model is driven by a mixture of in-situ and modelled discharges. In situ measurements are available at five locations. Two were obtained from the Global River Discharge Centre (GRDC) at Kinshasa and Bangui, and data for Kisangani, Ouesso and Lediba were obtained from local agencies in the Democratic Republic of the Congo and the Republic of Congo. Using the gauging station at Kinshasa as the downstream boundary, the remaining in-situ measurements account for 61 percent of the discharge and represent 72 percent of the total drainage area. Modelled discharges are used to account for the missing discharge and corresponding area. Calibration and validation of the model was undertaken using a mixture of in-situ measurements, discharge and water level at Kinshasa, and water surface heights along the main reach obtained from both laser and radar altimeters. Through the hydrodynamic model we will investigate: how important constraints, identified by a previous study, are to the behaviour of the Congo; what impacts the wetlands have on the Congo Basin; how the wetlands and main channel interact with each other. Our results will

Hydrothermal synthesis of 4ZnO·B2O3·H2O:Ln3+ (Ln=Eu, Tb) phosphors: Morphology-tunable and luminescence properties.

PubMed

Cao, Shiwei; Jiao, Yang; Han, Weifang; Ge, Chunhua; Song, Bo; Wang, Jie; Zhang, Xiangdong

2018-02-05

4ZnO·B 2 O 3 ·H 2 O:Ln 3+ (Ln=Eu, Tb) phosphors with different morphologies have been successfully synthesized via one-step hydrothermal method through regulating the molar amount of Eu 3+ and Tb 3+ . Comprehensive scanning electron microscopy (SEM), X-ray diffraction (XRD) Fourier transform infrared spectrum (FT-IR) and inductively coupled plasma atomic emission spectrometer (ICP-AES) characterizations all confirm that obtained products are 4ZnO·B 2 O 3 ·H 2 O:Ln 3+ (Ln=Eu, Tb). The experimental results displayed that the morphology and photoluminescence of compounds is regularly changed with increased the molar amount of rare earth ions. For the Eu 3+ -doped, Tb 3+ -doped and Eu 3+ /Tb 3+ co-doped 4ZnO·B 2 O 3 ·H 2 O phosphors of morphologies, the rod-like structures gradually changed to flower-like structures, fine wire-like structure and hybrid structure, respectively. To their photoluminescence, the Eu 3+ shows a red emission (615nm); the Tb 3+ shows a green emission (545nm); for the Eu 3+ /Tb 3+ co-doped 4ZnO·B 2 O 3 ·H 2 O phosphors, a combination of blue (5d-4f of Eu 2+ ), green ( 5 D 4 - 7 F 5 of Tb 3+ ) and red ( 5 D 0 - 7 F 2 of Eu 3+ ) emissions emerges to achieve white emission. In addition, the energy transfer among Eu 3+ , Eu 2+ and Tb 3+ ions was also discussed. Copyright © 2017. Published by Elsevier B.V.

Characterization of Terrestrial Water Dynamics in the Congo Basin Using GRACE and Satellite Radar Altimetry

NASA Technical Reports Server (NTRS)

Lee, Hyongki; Beighley, R. Edward; Alsdorf, Douglas; Jung, Hahn Chul; Shum, C. K.; Duan, Jianbin; Guo, Junyi; Yamazaki, Dai; Andreadis, Konstantinos

2011-01-01

The Congo Basin is the world's third largest in size (approx.3.7 million sq km), and second only to the Amazon River in discharge (approx.40,200 cu m/s annual average). However, the hydrological dynamics of seasonally flooded wetlands and floodplains remains poorly quantified. Here, we separate the Congo wetland into four 3deg 3deg regions, and use remote sensing measurements (i.e., GRACE, satellite radar altimeter, GPCP, JERS-1, SRTM, and MODIS) to estimate the amounts of water filling and draining from the Congo wetland, and to determine the source of the water. We find that the amount of water annually filling and draining the Congo wetlands is 111 cu km, which is about one-third the size of the water volumes found on the mainstem Amazon floodplain. Based on amplitude comparisons among the water volume changes and timing comparisons among their fluxes, we conclude that the local upland runoff is the main source of the Congo wetland water, not the fluvial process of river-floodplain water exchange as in the Amazon. Our hydraulic analysis using altimeter measurements also supports our conclusion by demonstrating that water surface elevations in the wetlands are consistently higher than the adjacent river water levels. Our research highlights differences in the hydrology and hydrodynamics between the Congo wetland and the mainstem Amazon floodplain.

The "fault of the Pool" along the Congo River between Kinshasa and Brazzaville, R(D)Congo is no more a myth: Paleostress from small-scale brittle structures

NASA Astrophysics Data System (ADS)

Delvaux, Damien; Ganza, Gloire; Kongota, Elvis; Fukiabantu, Guilain; Mbokola, Dim; Boudzoumou, Florent; Miyouna, Timothée; Gampio, Urbain; Nkodia, Hardy

2017-04-01

Small-scale brittle structures such as shear fractures and tension joints are well developed in the indurated Paleozoic Inkisi red sandstones of the West-Congo Supergroup in the "pool" region of Kinshasa and Brazzaville, along the Congo River. They appear to be related to the evolution of intraplate stresses during the late Cretaceous-Paleogene period, possibly related to the opening of the South Atlantic. However, inferring paleostresses from such structures is difficult due to the lack of clear kinematic indicators, so we used mainly the geometry, architecture and sequence of the joint systems to infer paleostresses. A limited number of kinematic indicators for slip sense (displaced pebbles, irregularities on striated surfaces, slickensides) or extension (plume joints) confirm the general conclusions of the joint architecture analysis. We found evidence for two major brittle deformation systems, leading to almost orthogonal fracture sets. They both started by the development of plume joints, which progressively evolved into open tension joints, isolated shear fractures and long (up to several hundred meters) brittle shear zones. The first system started to develop under NE-SW extension and evolved into strike-slip with NNW-SSE horizontal compression while the second (and later), started to develop under NW-SE extension and evolved into strike-slip with NNE-SSW horizontal compression. The second brittle deformation episode was associated with fluid flow as shown by the presence of palygorskite-calcite veins in the most prominent fractures of the second fracture system. Along the NE-SW brittle shear zones which run parallel to the Congo River, carbonate-rich fault-gauge lenses are filled by sand derived from the crushed adjacent walls and calcite vein fragments injected at a high fluid pressure, with late precipitation of palygorskite. Our study demonstrates the existence of two fault systems between Kinshasa and Brazzaville, the first one orthogonal to the trend

Low-temperature sequential pulsed chemical vapor deposition of ternary B{sub x}Ga{sub 1-x}N and B{sub x}In{sub 1-x}N thin film alloys

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

Haider, Ali, E-mail: ali.haider@bilkent.edu.tr, E-mail: biyikli@unam.bilkent.edu.tr; Kizir, Seda; Ozgit-Akgun, Cagla

In this work, the authors have performed sequential pulsed chemical vapor deposition of ternary B{sub x}Ga{sub 1-x}N and B{sub x}In{sub 1-x}N alloys at a growth temperature of 450 °C. Triethylboron, triethylgallium, trimethylindium, and N{sub 2} or N{sub 2}/H{sub 2} plasma have been utilized as boron, gallium, indium, and nitrogen precursors, respectively. The authors have studied the compositional dependence of structural, optical, and morphological properties of B{sub x}Ga{sub 1-x}N and B{sub x}In{sub 1-x}N ternary thin film alloys. Grazing incidence X-ray diffraction measurements showed that boron incorporation in wurtzite lattice of GaN and InN diminishes the crystallinity of B{sub x}Ga{sub 1-x}N and B{submore » x}In{sub 1-x}N sample. Refractive index decreased from 2.24 to 1.65 as the B concentration of B{sub x}Ga{sub 1-x}N increased from 35% to 88%. Similarly, refractive index of B{sub x}In{sub 1-x}N changed from 1.98 to 1.74 for increase in B concentration value from 32% to 87%, respectively. Optical transmission band edge values of the B{sub x}Ga{sub 1-x}N and B{sub x}In{sub 1-x}N films shifted to lower wavelengths with increasing boron content, indicating the tunability of energy band gap with alloy composition. Atomic force microscopy measurements revealed an increase in surface roughness with boron concentration of B{sub x}Ga{sub 1-x}N, while an opposite trend was observed for B{sub x}In{sub 1-x}N thin films.« less

Photoluminescence properties and structure of double perovskite Ba2ZnWO6:Eu3+, Li+ as a novel red emitting phosphor

NASA Astrophysics Data System (ADS)

Chen, Peng; Yang, Dingming; Hu, Wenyuan; Zhang, Jing; Wu, Yadong

2017-12-01

Novel red-emitting Ba2Zn1-x-yWO6:xEu3+, yLi+ phosphors were prepared using a high-temperature solid-state method, and the crystal structure, the photoluminescence properties and the doping concentrations of Eu3+ and Li+ were investigated. The results show that these phosphors can be excited by near-ultraviolet light (250-400 nm) and co-doped Li+ can significantly enhance their PL performance. An intense red emission peak at 598 nm (5D0-7F1 transitions) was observed with an excitation wavelength of 316 nm. The CIE chromaticity coordinates of the phosphors are located in the red region, indicating that the BZW:Eu3+, Li+ phosphor holds promise as a red phosphor for near-ultraviolet excited WLEDs.

Intense green and red upconversion emission of Er3+,Yb3+ co-doped CaZrO3 obtained by a solution combustion reaction

NASA Astrophysics Data System (ADS)

Singh, Vijay; Kumar Rai, Vineet; Haase, Markus

2012-09-01

CaZrO3 phosphors co-doped with Er3+ and Yb3+ ions have been prepared by the urea combustion route. The formation of the orthorhombic phase of CaZrO3 was confirmed by powder x-ray diffraction. The absorption in the 280-1800 nm region and excitation spectrum corresponding to the emission at 545 nm for CaZrO3:Er3+/CaZrO3:Er3+,Yb3+ phosphors have been recorded. Upon excitation at 978 nm, the material displays strong energy transfer upconversion emission in the green and red spectral regions. The upconversion emission of the CaZrO3:Er3+,Yb3+ co-doped material shows an increased red-to-green ratio, indicating cross relaxation between Er3+ ions.

Synthesis and luminescence properties of Eu3+-doped KLa(MoO4)2 red-emitting phosphor

NASA Astrophysics Data System (ADS)

Zuo, Haoqiang; Liu, Yun; Li, Jinyang; Shi, Xiaolei; Gao, Weiping

2015-09-01

Eu3+-doped KLa(MoO4)2 phosphors were synthesized by a simple hydrothermal method. X-ray diffraction (XRD) analysis demonstrated that the as-prepared products were pure monoclinic phase of KLa(MoO4)2. Field emission scanning electron microscopy (FE-SEM) images indicated that the morphology of the prepared phosphors evolved from uniform spherical-like to irregular elliposid-like with increase of the concentration. The photoluminescence (PL) spectra displayed that the phosphors show strong red light around 618 nm, attributed to 5D0 → 7F2 transition of Eu3+ ion under 465 nm excitation, and the optimal Eu3+ doping concentration was about 15 mol.% based on the concentration dependent emission spectra. According to Dexter's theory the electric dipole-dipole interaction (D-D) is the main mechanism for energy transfer between Eu3+ and Eu3+ ions. The CIE chromaticity (x, y) of the phosphors were about (0.65, 0.35) and it is close to the standard red chromaticity of NTSC. Therefore, the phosphors could be used as red phosphors for white light-emitting diodes.

The Upper Jurassic Stanleyville Group of the eastern Congo Basin: An example of perennial lacustrine system

NASA Astrophysics Data System (ADS)

Caillaud, Alexis; Blanpied, Christian; Delvaux, Damien

2017-08-01

The intracratonic Congo Basin, located in the Democratic Republic of Congo (DRC), is the largest sedimentary basin of Africa. The Jurassic strata outcrop along its eastern margin, south of Kisangani (formerly Stanleyville). In the last century, the Upper Jurassic Stanleyville Group was described as a lacustrine series containing a thin basal marine limestone designed as the ;Lime Fine; beds. Since the proposal of this early model, the depositional environment of the Stanleyville Group, and especially the possible marine incursion, has been debated, but without re-examining the existing cores, outcrop samples and historical fossils from the type location near Kisangani that are available at the Royal Museum for Central Africa (MRAC/KMMA, Tervuren, Belgium). In order to refine the former sedimentology, a series of nine exploration cores drilled in the Kisangani sub-basin have been described. This study aims at integrating sedimentary facies in existing sedimentary models and to discuss the hypothesis of the presence of Kimmeridgian marine deposits along the Congo River near Kisangani, a region which lies in the middle of the African continent. Eight facies have been identified, which permit a reinterpretation of the depositional environment and paleogeography of the Stanleyville Group. The base of the Stanleyville Group is interpreted to represent a conglomeratic fluvial succession, which filled an inherited Triassic paleotopography. Above these conglomerates, a transition to a typically lacustrine system is interpreted, which includes: (1) a basal profundal, sublittoral (brown to dark fine-grained siltstones with microbial carbonates, i.e., the ;Lime Fine; beds) and littoral lacustrine series; covered by (2) a sublittoral to profundal interval (brown to dark organic-rich, fine-grained siltstones), which corresponds to the maximum extent of the paleo-lake; and, finally (3) a shallow lacustrine series (greenish calcareous siltstones and sandstones with red siltstones

X-48B Preliminary Flight Test Results

NASA Technical Reports Server (NTRS)

Taylor, Brian R.

2009-01-01

This slide presentation reviews the preliminary Flight tests of the X-48B development program. The X-48B is a blended wing body aircraft that is being used to test various features of the BWB concept. The research concerns the following: (1) Turbofan Development, (2) Intelligent Flight Control and Optimization, (3) Airdata Calibration (4) Parameter Identification (i.e., Determination of the parameters of a mathematical model of a system based on observation of the system inputs and response.)

The fluorescence and resonance Rayleigh scattering spectra study on the interactions of palladium (II)-Nootropic chelate with Congo red and their analytical applications

NASA Astrophysics Data System (ADS)

Chen, Fang; Peng, Jingdong; Liu, Shaopu; Peng, Huanjun; Pan, Ziyu; Bu, Lingli; Xiao, Huan; Zhang, Ruiwen

2017-04-01

A highly sensitive detection approach of resonance Rayleigh scattering spectra (RRS) is firstly applied to analyzing nootropic drugs including piracetam (PIR) and oxiracetam (OXI). In HCl-NaAc buffer solution (pH = 3.0), the OXI chelated with palladium (II) to form the chelate cation [Pd2·OXI]2 +, and then reacted with Congo red (CGR) by virtue of electrostatic attraction and hydrophobic force to form binary complex [Pd2·OXI]. CGR2, which could result in the great enhancement of RRS. The resonance Rayleigh scattering signal was recorded at λex = λem = 375 nm. This mixture complex not only has higher RRS, but also makes contribution to significant increase of fluorescence, and the same phenomena also were discovered in PIR. The enhanced RRS intensity is in proportion to the PIR and OXI concentration in the range of 0.03-3.0 μg mL- 1, and the detection limit (DL) of RRS method for PIR and OXI is 2.3 ng mL- 1 and 9.7 ng mL- 1. In addition, the DL of fluorescence method for PIR and OXI is 8.4 μg mL- 1 and 19.5 μg mL- 1. Obviously, the RRS is the highly sensitive method, and the recoveries of the two kinds of nootropic drugs were range from 100.4% to 101.8.0% with RSD (n = 5) from 1.1% to 3.1% by RRS method. This paper not only investigated the optimum conditions for detecting nootropics with using RRS method, but also focused on the reasons for enhancing RRS intensity and the reaction mechanism, which in order to firm and contract the resultant. Finally, The RRS method has been applied to detect nootropic drugs in human urine samples with satisfactory results. Fig. S2. The effect of ionic strength: Pd (II)-CGR system (curve a); Pd (II)-OXI-CGR system (curve b); Pd (II)-PIR- CGR system (curve c). Pd (II): 2.0 × 10- 4 mol L- 1; CGR: 1.0 × 10- 5 mol L- 1; OXI: 1.5 μg mL- 1; PIR: 2 μg mL- 1; NaCl: 1 mol L- 1. Fig. S3. The effect of time: Pd (II)-OXI-CGR system (curve a); Pd (II)-PIR-CGR system (curve b). Pd (II): 2.0 × 10- 4 mol L- 1; CGR: 1.0 × 10- 5 mol L- 1

Effect of replacement of Ca by Zn on the structure and optical property of CaTiO3:Eu(3+) red phosphor prepared by sol-gel method.

PubMed

Wang, Yulong; Zhang, Wentao; Zhang, Peicong; Li, Junfeng; Long, Jianping

2015-08-01

Eu(3+)-doped calcium titanate red phosphors, Ca(1-x)Znx TiO3:Eu(3+), were prepared by the sol-gel method. The structure of prepared Ca(1-x)Znx TiO3:Eu(3+) phosphors were investigated by X-ray diffraction and infrared spectra. Due to the (5) D0  → (7) F1-3 electron transitions of Eu(3+) ions, photoluminescence spectra showed a red emission at about 619 nm under excitation of 397 nm and 465 nm, respectively. When zinc was added to the host, the luminescent intensity of Ca(1-x)ZnxTiO3:Eu(3+) was markedly improved several fold compared with that of CaTiO3:Eu(3+). Ca0.9Zn0.1TiO3:Eu(3+) also had higher luminescence intensity than the commercially available Y2 O3:Eu(3+) phosphors under UV light excitation. Copyright © 2014 John Wiley & Sons, Ltd.

[Enhanced electro-chemical oxidation of Acid Red 3R solution with phosphotungstic acid supported on gamma-Al2O3].

PubMed

Yue, Lin; Wang, Kai-Hong; Guo, Jian-Bo; Yang, Jing-Liang; Liu, Bao-You; Lian, Jing; Wang, Tao

2013-03-01

Supported phosphotungstic acid catalysts on gamma-Al2O3 (HPW/gamma-Al2O3) were prepared by solution impregnation and characterized by FTIR, XRD, TG-DTA and SEM. The heteropolyanion shows a Keggin structure. Electro-chemical oxidation of Acid Red 3R was investigated in the presence of HPW supported on gamma-Al2O3 as packing materials in the reactor. The results show that HPW/gamma-Al2O3 has a good catalytic activity for decolorization of Acid Red 3R. When HPW loading was 4.6%, pH value of Acid Red 3R was 3, the voltage was 25.0 V, air-flow was 0.04 m3 x h(-1), and electrode span was 3.0 cm, the decolorization efficiency of Acid Red 3R can reach 97.6%. The removal rate of color had still about 80% in this electro-chemical oxidation system, after HPW/gamma-Al2O3 was used for 10 times, but active component loss existed. The interim product was analyzed by means of Vis-UV absorption spectrum. It shows that the conjugated structure of dye is destroyed primarily.

Spectral energy distribution simulations of a possible ring structure around the young, red brown dwarf G 196-3 B

NASA Astrophysics Data System (ADS)

Zakhozhay, Olga V.; Zapatero Osorio, María Rosa; Béjar, Víctor J. S.; Boehler, Yann

2017-01-01

The origin of the very red optical and infrared colours of intermediate-age (˜10-500 Myr) L-type dwarfs remains unknown. It has been suggested that low-gravity atmospheres containing large amounts of dust may account for the observed reddish nature. We explored an alternative scenario by simulating debris disc around G 196-3 B, which is an L3 young brown dwarf with a mass of ˜15 MJup and an age in the interval 20-300 Myr. The best-fit solution to G 196-3 B's photometric spectral energy distribution from optical wavelengths through 24 μm corresponds to the combination of an unreddened L3 atmosphere (Teff ≈ 1870 K) and a warm (≈1280 K), narrow (≈0.07-0.11 R⊙) debris disc located at very close distances (≈0.12-0.20 R⊙) from the central brown dwarf. This putative, optically thick, dusty belt, whose presence is compatible with the relatively young system age, would have a mass ≥7 × 10-10 M⊕ comprised of submicron/micron characteristic dusty particles with temperatures close to the sublimation threshold of silicates. Considering the derived global properties of the belt and the disc-to-brown dwarf mass ratio, the dusty ring around G 196-3 B may resemble the rings of Neptune and Jupiter, except for its high temperature and thick vertical height (≈6 × 103 km). Our inferred debris disc model is able to reproduce G 196-3 B's spectral energy distribution to a satisfactory level of achievement.

Half-metallic magnetism in Ti 3Co 5-xFe xB 2

DOE PAGES

Pathak, Rohit; Ahamed, Imran; Zhang, W. Y.; ...

2017-02-08

Here, bulk alloys and thin films of Fe-substituted Ti 3Co 5B 2 have been investigated by first-principle density-functional calculations. The series, which is of interest in the context of alnico magnetism and spin electronics, has been experimentally realized in nanostructures but not in the bulk. Our bulk calculations predict paramagnetism for Ti 3Co 5B 2, Ti 3Co 4FeB 2 and Ti 3CoFe 4B 2, whereas Ti 3Fe 5B 2 is predicted to be ferromagnetic. The thin films are all ferromagnetic, indicating that moment formation may be facilitated at nanostructural grain boundaries. One member of the thin-film series, namely Ti 3CoFemore » 4B 2, is half-metallic and exhibits perpendicular easy-axis magnetic anisotropy. The half-metallicity reflects the hybridization of the Ti, Fe and Co 3d orbitals, which causes a band gap in minority spin channel, and the limited equilibrium solubility of Fe in bulk Ti 3Co 5B 2 may be linked to the emerging half-metallicity due to Fe substitution.« less

Half-metallic magnetism in Ti 3Co 5-xFe xB 2

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

Pathak, Rohit; Ahamed, Imran; Zhang, W. Y.

Here, bulk alloys and thin films of Fe-substituted Ti 3Co 5B 2 have been investigated by first-principle density-functional calculations. The series, which is of interest in the context of alnico magnetism and spin electronics, has been experimentally realized in nanostructures but not in the bulk. Our bulk calculations predict paramagnetism for Ti 3Co 5B 2, Ti 3Co 4FeB 2 and Ti 3CoFe 4B 2, whereas Ti 3Fe 5B 2 is predicted to be ferromagnetic. The thin films are all ferromagnetic, indicating that moment formation may be facilitated at nanostructural grain boundaries. One member of the thin-film series, namely Ti 3CoFemore » 4B 2, is half-metallic and exhibits perpendicular easy-axis magnetic anisotropy. The half-metallicity reflects the hybridization of the Ti, Fe and Co 3d orbitals, which causes a band gap in minority spin channel, and the limited equilibrium solubility of Fe in bulk Ti 3Co 5B 2 may be linked to the emerging half-metallicity due to Fe substitution.« less

Study on photoluminescence and energy transfer of Eu3+/Sm3+ single-doped and co-doped BaB8O13 phosphors

NASA Astrophysics Data System (ADS)

Lephoto, Mantwa A.; Tshabalala, Kamohelo G.; Motloung, Selepe J.; Ahemen, Iorkyaa; Ntwaeaborwa, Odireleng M.

2018-04-01

A series of Sm3+, Eu3+ and Eu3+- Sm3+ doped BaB8O13 were synthesized by using a solution combustion method. When excited at 394 nm, BaB8O13: Eu3+ emits red light, and the strongest peak was located at 614 nm, which is attributed to the 5D0→7F2 transition of Eu3+. BaB8O13: Sm3+ produced red-orange light, and the major emission peak was located at 596 nm under the 402 nm radiation excitation, which is assigned to the 4G5/2→6H7/2 transition of Sm3+. When excited at 402 nm, the PL emission intensity from BaB8O13: 0.05Eu3+; 0.005Sm3+ at 614 nm was enhanced considerably compared to that of the sample without Sm3+, suggesting that energy was transferred from Sm3+ to Eu3+. The Commission International de I‧Eclairage (CIE) chromaticity coordinates of BaB8O13: 0.05Eu3+; 0.005Sm3+ powder phosphor (0.637, 0.362) are located in the red region indicating that the phosphor can serve as a source of red light in LEDs.

The Enhanced Red Emission and Improved Thermal Stability of CaAlSiN3:Eu2+ Phosphors by Using Nano-EuB6 as Raw Material

PubMed Central

Liu, Wen-Quan; Wu, Dan; Chang, Hugejile; Duan, Ru-Xia; Wu, Wen-Jie; Amu, Guleng; Bao, Fu-Quan; Tegus, Ojiyed

2018-01-01

Synthesizing phosphors with high performance is still a necessary work for phosphor-converted white light-emitting diodes (W-LEDs). In this paper, three series of CaAlSiN3:Eu2+ (denoted as CASN:Eu2+) phosphors using Eu2O3, EuN and EuB6 as raw materials respectively are fabricated by under the alloy precursor normal pressure nitridation synthesis condition. We demonstrate that CASN:Eu2+ using nano-EuB6 as raw material shows higher emission intensity than others, which is ascribed to the increment of Eu2+ ionic content entering into the crystal lattice. An improved thermal stability can also be obtained by using nano-EuB6 due to the structurally stable status, which is assigned to the partial substitution of Eu–O (Eu–N) bonds by more covalent Eu–B ones that leads to a higher structural rigidity. In addition, the W-LEDs lamp was fabricated to explore its possible application in W-LEDs based on blue LEDs. Our results indicate that using EuB6 as raw materials can provide an effective way of enhancing the red emission and improving the thermal stability of the CASN:Eu2+ red phosphor. PMID:29370148

Synthesis and up-conversion luminescence of Er{sup 3+} and Y b{sup 3+} codoped nanocrystalline tetra- (KLaP{sub 4}O{sub 12}) and pentaphosphates (LaP{sub 5}O{sub 14})

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

Marciniak, L., E-mail: l.marciniak@int.pan.wroc.pl; Stefanski, M.; Tomala, R.

2015-09-07

The up-converting nanocrystals of KLa{sub 0.95}Er{sub 0.05}Y b{sub x}P{sub 4}O{sub 12} and La{sub 0.95−x}Er{sub 0.05}Y b{sub x}P{sub 5}O{sub 14} were prepared using co-precipitation method. The spectroscopic properties of these materials were investigated in a function of Y b{sup 3+} concentration. The up-conversion emission, power dependence of emission intensities, and the luminescence decay times were investigated. It was found that the green to red and {sup 2}H{sub 11/2} → {sup 4}I{sub 15/2} to {sup 4}S{sub 3/2} → {sup 4}I{sub 15/2} emission intensity ratio were strongly affected by the Y b{sup 3+} concentration. Moreover, the order of up-conversion emission and threshold powermore » rises up with Y b{sup 3+} concentration for {sup 4}S{sub 3/2} → {sup 4}I{sub 15/2} transition. The luminescence decay time of the {sup 4}S{sub 3/2} → {sup 4}I{sub 15/2} emission increases with Y b{sup 3+} concentration while the {sup 4}F{sub 9/2} → {sup 4}I{sub 15/2} emission is independent of dopant concentration. The influence of the Y b{sup 3+} concentration on the up-conversion emission intensities was discussed in terms of concentration dependent hetero looped photon avalanche process. A comparison of the up-conversion properties of KLa{sub 0.95}Er{sub 0.05}Y b{sub x}P{sub 4}O{sub 12} and La{sub 0.95−x}Er{sub 0.05}Y b{sub x}P{sub 5}O{sub 14} nanocrystals was presented.« less

Evolution of Fermi Surface Properties in CexLa1-xB6 and PrxLa1-xB6

NASA Astrophysics Data System (ADS)

Endo, Motoki; Nakamura, Shintaro; Isshiki, Toshiyuki; Kimura, Noriaki; Nojima, Tsutomu; Aoki, Haruyoshi; Harima, Hisatomo; Kunii, Satoru

2006-11-01

We report the de Haas-van Alphen (dHvA) effect measurements of the Fermi surface properties in LaB6, CexLa1-xB6 (x = 0.1, 0.25, 0.5, 0.75, 1.0) and PrxLa1-xB6 (x = 0.25, 0.5, 0.75, 1.0) with particular attention to the spin dependence of the Fermi surface properties. The Fermi surface shape and dimension of CexLa1-xB6 change considerably with Ce concentration, while those of PrxLa1-xB6 change very slightly up to x = 0.75, and in PrB6 the Fermi surface splits into the up and down spin Fermi surfaces. The effective mass of CexLa1-xB6 increases considerably with Ce concentration and is nearly proportional to the number of Ce ions, whereas that of PrxLa1-xB6 increases slightly with Pr concentration. In CexLa1-xB6 the effective mass depends very strongly on field and increases divergently with decreasing field, while that of PrxLa1-xB6 increases slightly with decreasing field. The contribution to the dHvA signal from the conduction electrons of one spin direction diminishes with Ce concentration and appears to disappear somewhere around x = 0.25--0.5. A weak spin dependence is also found in PrxLa1-xB6. The behaviors of CexLa1-xB6 and PrxLa1-xB6 are compared to discuss the origin of the spin dependence of the Fermi surface properties.

Hydrothermal synthesis of 4ZnO·B2O3·H2O:Ln3 + (Ln = Eu, Tb) phosphors: Morphology-tunable and luminescence properties

NASA Astrophysics Data System (ADS)

Cao, Shiwei; Jiao, Yang; Han, Weifang; Ge, Chunhua; Song, Bo; Wang, Jie; Zhang, Xiangdong

2018-02-01

4ZnO·B2O3·H2O:Ln3 + (Ln = Eu, Tb) phosphors with different morphologies have been successfully synthesized via one-step hydrothermal method through regulating the molar amount of Eu3 + and Tb3 +. Comprehensive scanning electron microscopy (SEM), X-ray diffraction (XRD) Fourier transform infrared spectrum (FT-IR) and inductively coupled plasma atomic emission spectrometer (ICP-AES) characterizations all confirm that obtained products are 4ZnO·B2O3·H2O:Ln3 + (Ln = Eu, Tb). The experimental results displayed that the morphology and photoluminescence of compounds is regularly changed with increased the molar amount of rare earth ions. For the Eu3 +-doped, Tb3 +-doped and Eu3 +/Tb3 + co-doped 4ZnO·B2O3·H2O phosphors of morphologies, the rod-like structures gradually changed to flower-like structures, fine wire-like structure and hybrid structure, respectively. To their photoluminescence, the Eu3 + shows a red emission (615 nm); the Tb3 + shows a green emission (545 nm); for the Eu3 +/Tb3 + co-doped 4ZnO·B2O3·H2O phosphors, a combination of blue (5d-4f of Eu2 +), green (5D4-7F5 of Tb3 +) and red (5D0-7F2 of Eu3 +) emissions emerges to achieve white emission. In addition, the energy transfer among Eu3 +, Eu2 + and Tb3 + ions was also discussed.

Proton Induced X-ray Emission Spectroscopy of Red Wine Samples Using the Union College Pelletron Accelerator

NASA Astrophysics Data System (ADS)

Schuff, Katie; Labrake, Scott

2010-11-01

A 1-megavolt tandem electrostatic Pelletron particle accelerator housed at Union College was used to measure the elemental composition and concentration of homemade Cabernet and Merlot red wine samples. A beam of 1.8-MeV protons directed at an approximately 12-μm thin Mylar substrate onto which 8-μL of concentrated red wine was dried caused inner shell electrons to be ejected from the target nuclei and these vacancies are filled through electronic transitions of higher orbital electrons accompanied by the production of an x-ray photon characteristic of the elemental composition of the target. This is the PIXE Method. Data on the intensity versus energy of the x-rays were collected using an Amptek silicon drift detector and were analyzed to determine the elemental composition and the samples were found to contain P, S, K, Cl, Ca, Sc, Mn, Al, Fe, & Co. Elemental concentrations were determined using the analysis package GUPIX. It is hypothesized that the cobalt seen is a direct result of the uptake by the grapes and as a product of the fermentation process a complex of vitamin B12 is produced.

Crystal structures of [NEt3H]5[XCoIIW11O39]·3H2O (X = P or As)

USGS Publications Warehouse

Evans, H.T.; Weakley, T.J.R.; Jameson, G.B.

1996-01-01

The orthorhombic crystal structures of [NEt3H]5[XCoIIW11O39]·3H2O for X = P and As have been determined with data collected at room temperature, and for X = P at –100 °C, using Mo-Kα radiation. For the latter the space group is Pna21, a= 21.670(11), b= 14.805(4), c= 20.393(5)Å and Z= 4. The structure consists of chains of α-Keggin-type molecules joined by W–O–links aligned in the a-axis direction. The Co/W occupancy at the link is disordered, with 61% Co on one side and 39% on the other. Further probable disorder, by lamellar merohedral twinning on (001) and by misorientation of the triethylammonium ions, has obscured the ethyl groups and the water molecules. In polarized light the crystals are deep wine-red normal to the chains (in the b direction), but nearly colourless in the a and c directions. The structure of the arsenate is similar to that of the phosphate.

Evaluating desiccation sensitivity of northern red oak acorns using x-ray image analysis

Treesearch

Rosa C. Goodman; Douglass F. Jacobs

2005-01-01

Desiccation of northern red oak (Quercus rubra L.) acorns can have a major influence on seed viability. Recalcitrant behavior of northern red oak acorns was studied to examine the effects of moisture content (MC) on germination and early growth. Because it is rapid and non-destructive, X-ray image analysis was chosen to assess cotyledon damage in...

27 CFR 21.122 - Pyridine bases.

Code of Federal Regulations, 2010 CFR

2010-04-01

... with 1 N H2SO4 until a drop of the mixture placed upon Congo paper shows a distinct blue border, which soon disappears. A minimum of 9.5 ml of the acid must be required for the end point. (Congo paper: filter paper treated with 0.1 percent aqueous solution of Congo red and dried.) (b) Distillation range...

27 CFR 21.122 - Pyridine bases.

Code of Federal Regulations, 2012 CFR

2012-04-01

... with 1 N H2SO4 until a drop of the mixture placed upon Congo paper shows a distinct blue border, which soon disappears. A minimum of 9.5 ml of the acid must be required for the end point. (Congo paper: filter paper treated with 0.1 percent aqueous solution of Congo red and dried.) (b) Distillation range...

27 CFR 21.122 - Pyridine bases.

Code of Federal Regulations, 2011 CFR

2011-04-01

... with 1 N H2SO4 until a drop of the mixture placed upon Congo paper shows a distinct blue border, which soon disappears. A minimum of 9.5 ml of the acid must be required for the end point. (Congo paper: filter paper treated with 0.1 percent aqueous solution of Congo red and dried.) (b) Distillation range...

27 CFR 21.122 - Pyridine bases.

Code of Federal Regulations, 2014 CFR

2014-04-01

... with 1 N H2SO4 until a drop of the mixture placed upon Congo paper shows a distinct blue border, which soon disappears. A minimum of 9.5 ml of the acid must be required for the end point. (Congo paper: filter paper treated with 0.1 percent aqueous solution of Congo red and dried.) (b) Distillation range...

27 CFR 21.122 - Pyridine bases.

Code of Federal Regulations, 2013 CFR

2013-04-01

... with 1 N H2SO4 until a drop of the mixture placed upon Congo paper shows a distinct blue border, which soon disappears. A minimum of 9.5 ml of the acid must be required for the end point. (Congo paper: filter paper treated with 0.1 percent aqueous solution of Congo red and dried.) (b) Distillation range...

John B. McKay after X-15 flight #3-27-44

NASA Image and Video Library

1964-03-13

John B. McKay was one of the first pilots assigned to the X-15 flight research program at NASA's Flight Research Center, Edwards, Calif. As a civilian research pilot and aeronautical engineer, he made 30 flights in X-15s from October 28, 1960, until September 8, 1966. His peak altitude was 295,600 feet, and his highest speed was 3863 mph (Mach 5.64). McKay was with the NACA and NASA from February 8,1951 until October 5, 1971 and specialized in high-speed flight research programs. He began as an NACA intern, but assumed pilot status on July 11, 1952. In addition to the X-l5, he flew such experimental aircraft as the D-558-1, D-558-2, X-lB, and the X-lE. He has also served as a research pilot on flight programs involving the F-100, F-102, F-104, and the F-107. Born on December 8, 1922, in Portsmouth, Va., McKay graduated from Virginia Polytechnic Institute in 195O with a Bachelor of Science degree in Aeronautical Engineering. During World War II he served as a Navy pilot in the Pacific Theater, earning the Air Medal and Two Clusters, and a Presidential Unit Citation. McKay wrote several technical papers, and was a member of the American Institute of Aeronautics and Astronautics, as well as the Society of Experimental Test Pilots. He passed away on April 27, 1975.

Eu2+-Doped Sr2B2-2xSi2+3xAl2-xN8+x: A Boron-Containing Orange-Emitting Nitridosilicate with Interesting Composition-Dependent Photoluminescence Properties.

PubMed

Ten Kate, Otmar M; Xie, Rong-Jun; Wang, Chun-Yun; Funahashi, Shiro; Hirosaki, Naoto

2016-11-07

Novel Sr 2-y Eu y B 2-2x Si 2+3x Al 2-x N 8+x phosphors were investigated as a function of the boron and aluminum over silicon ratio and as a function of the Eu 2+ concentration. Samples were prepared via solid-state reaction synthesis by carefully controlling the synthesis conditions and composition. At high boron and aluminum content, that is, x = 0, a Eu 2+ 5d-4f emission is observed of which the maximum shifts from 595 nm for low Eu concentrations (y = 0.005) toward 623 nm for high Eu concentrations (y = 0.5). The samples can be excited by UV or blue light up to ∼475 nm. Substitution of [B 2 Al] 9+ units by [Si 3 N] 9+ units, increasing x up to 0.15, greatly improves the luminescence efficiency up to 46% and shows a very large redshift of the excitation bands with ∼100 nm, while the emission band shifts with ∼10 nm. The shifts are attributed to the lowering of the 5d level as a result of the decreased Eu-N distance upon substitution. Temperature-dependent measurements show that the Eu 2+ 5d-4f emission is largely thermally quenched at room temperature for x = 0 due to thermal ionization toward the conduction band, explaining the low luminescence efficiency. The lowering of the 5d level at larger values of x reduces the thermal ionization and consequently increases the thermal stability and quantum efficiency, resulting in strongly luminescent blue-to-orange conversion phosphors that are interesting for light-emitting diode applications.

Tunable Optical Properties and Increased Thermal Quenching in the Blue-Emitting Phosphor Series: Ba 2 (Y 1–x Lu x ) 5 B 5 O 17 :Ce 3+ ( x = 0–1)

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

Hermus, Martin; Phan, Phu-Cuong; Duke, Anna C.

The preparation of cerium-substituted barium lutetium borate, Ba2Lu5B5O17:Ce3+, is achieved using high temperature solid state synthesis. This compound crystallizes in the Ba2Y5B5O17-type structure and shows an efficient blue emission (λmax = 447 nm) when excited by UV-light (λex = 340 nm) with a photoluminescent quantum yield near 90%, a fast luminescence decay time (<40 ns), and a thermal quenching temperature of 452 K. Further, preparing a solid solution following Ba2(Y1–xLux)5B5O17:Ce3+ (x = 0, 0.25, 0.50, 0.75, 1) confirms that all compounds are isostructural and follow Vegard’s law. Substituting Y3+ for Lu3+ yields a nearly constant emission spectrum that blue-shifts bymore » only 9 nm and has a consistent luminescence lifetime across the range prepared. The photoluminescent quantum yield (PLQY) and thermal quenching (T50) of the solid solution, however, are dramatically impacted by the composition, with the PLQY decreasing to ≈70% and the T50 dropping 49 K going from x = 1 to x = 0. These significant changes in the optical properties likely stem from enhanced structural rigidity as the larger, more polarizable Y3+ is substituted for the smaller, harder Lu3+ cation. These results highlight the importance of optimizing chemical bonding to improve a phosphor’s optical properties.« less

Synthesis of three bromophenols from red algae as PTP1B inhibitors

NASA Astrophysics Data System (ADS)

Guo, Shuju; Li, Jing; Li, Ting; Shi, Dayong; Han, Lijun

2011-01-01

Bromophenols are a set of natural products widely distributed in seaweed, most of which exhibit interesting and useful biological activities. To develop a reliable and efficient synthetic route to these natural bromophenols, three of them, 3,4-dibromo-5-(2'-bromo-3',4'-dihydroxy-6'-methoxymethyl-benzyl)-benzene-1,2-diol (compound 9), 3,4-dibromo-5-(2'-bromo-6'-ethoxy methyl-3',4'-dihydroxybenzyl)-benzene-1,2-diol (compound 10), and 3-bromo-4-(3'-bromo-4',5'-dihydroxy benzyl)-5-(ethoxymethyl)-benzene-1,2-diol (compound 14), isolated from red marine algae, have been synthesized in eight steps with an overall yield of 14.4%, 14.4%, and 18.2% respectively, via a practical approach employing bromination, Wolff-Kishner-Huang reduction and a Friedel-Crafts reaction as key steps. The protein tyrosine phosphatase 1B (PTP1B) inhibitory activities of the synthetic compounds were evaluated by the colorimetric assay. The results show that these compounds are moderate PTP1B inhibitors. The synthesis of these bromophenol derivatives makes in vivo studies of their structure-activity relationships and inhibition activity against PTP1B possible.

Discovery of the Red-Skewed K-alpha Iron Line in Cyg X-2 with Suzaku

NASA Technical Reports Server (NTRS)

Shaposhnikov, Nikolai; Titarchuk, Lev; Laurent, Philippe

2008-01-01

We report on the Suzaku observation of neutron star low-mass X-ray binary Cygnus X-2 which reveals strong iron K-alpha emission line. The line profile shows a prominent red wing extending down to 4 keV. This discovery increases the number of neutron star sources where red-skewed iron lines were observed and strongly suggests that this phenomenon is common not only in black holes but also in other types of compact objects. We examine the line profile by fitting it with the model which attributes its production to the relativistic effects due to disk reflection of X-ray radiation. We also apply an alternative model where the red wing is a result of down-scattering effect of the first order with respect to electron velocity in the wind outflow. Both models describe adequately the observed line profile. However, the X-ray variability in a state similar to that in the Suzaku observation which we establish by analysing RXTE observation favors the wind origin of the line formation.

X-1E launch from B-50 mothership

NASA Technical Reports Server (NTRS)

1950-01-01

Beginning in 1946, two XS-1 experimental research aircraft (later redesignated X-1s) conducted pioneering tests at Muroc Army Air Field (now Edwards Air Force Base) in California to obtain flight data on conditions in the transonic speed range. These early tests culminated on October 14, 1947, in the first piloted flight faster than Mach 1.0, the speed of sound. During November, 1947, the Air Force authorized studies that led to a contract (W-33-038-ac-20062) with Bell Aircraft to build four (later three) improved X-1 aircraft (the X-1C being cancelled). Designated X-1A (#48-1384), X-1B (#48-1385), and X-1D (#48-1386), the airplanes were ready by late 1950. The aircraft were about five feet longer and 2,500 lbs. heavier than the original X-craft planes. They used the 8-percent wing like the earlier X-craft. The D-model had a low-pressure turbo-pump and the B model was fitted with a prototype hydrogen peroxide reaction control system for later aircraft to use in exoatmospheric research flights. Access was through a lift-off canopy. The planes were finished in their bare metal color and white. The X-1D was ready first, but on what was intended to be its second flight (August 22, 1951) it was jettisoned and crashed at Muroc after an aerial explosion while still mated to its mother (B-50A [#46-006A]) ship. The long-delayed X-1 #3 airplane with the turbine pump was finally completed for the NACA in 1951. It made its first glide flight on July 20, 1951, with NACA pilot Joseph Cannon. Its second and final captive flight was on November 9, 1951. It was destroyed on the ground by an explosion and fire along with its B-50A mother ship while attempting to jettison fuel. The X-1A arrived at Muroc in January, 1953 and had its first powered flight on February 21, 1953. On December 8, 1953 with Yeager as pilot, the aircraft investigated high-speed stability and control issues. The X-1A was turned over to the NACA, but was lost to aerial explosion on August 8, 1955, shortly before

Synthesis and crystal structures of new oxyapatites BiCa{sub 4-x}La{sub x}(VO{sub 4}){sub 3-x}(GeO{sub 4}){sub x}O, x=1-3

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

Zhuravlev, V.D., E-mail: zhvd@ihim.uran.ru; Tyutyunnik, A.P.; Zubkov, V.G.

2012-10-15

New germanate-vanadates with the general formula BiCa{sub 4-x}La{sub x}(VO{sub 4}){sub 3-x}(GeO{sub 4}){sub x}O, x=1-3, have been synthesized by the nitrate-citrate method and characterized. Structural refinement based on X-ray powder diffraction data showed that these compounds are isostructural with BiCa{sub 4}(VO{sub 4}){sub 3}O (space group P6{sub 3}/m (N 176), Z=2, a=9.8327-9.8755(3), and c=7.1203-7.2133(2) ). They may be viewed as continuous series of solid solutions where Ca{sup 2+} and V{sup 5+} cations in the crystal lattice of vanadate BiCa{sub 4}(VO{sub 4}){sub 3}O are replaced by La{sup 3+} and Ge{sup 4+} cations. In the process of substitution, the La{sup 3+} cations occupy mainlymore » the 4f lattice sites of the germanate-vanadate oxyapatites, but the filling of the 4f and 6h lattice sites in the germanate BiCaLa{sub 3}(GeO{sub 4}){sub 3} is equivalent. IR and Raman spectra were studied. The Raman spectra clearly show a two-mode behavior: the lines of GeO{sub 4} and VO{sub 4} are separated from each other, and the (V/Ge)O{sub 4} tetrahedra exhibit a quasi-independent behavior. - Graphical abstract: Schematic drawing of the BiCa{sub 3}La(VO{sub 4}){sub 2}(GeO{sub 4})O structure in projection on the ac plane. Green-V and Ge, red-Ca(1) and La(1), yellow-Ca(2), La(2) and Bi, dark-blue-O(1)-O(4), blue-O(5). Highlights: Black-Right-Pointing-Pointer The citrate synthesis of germanate-vanadate oxyapatites. Black-Right-Pointing-Pointer The synthesized compounds crystallize in the hexagonal symmetry. Black-Right-Pointing-Pointer A single series of solid solutions BiCa{sub 4-x}La{sub x}(VO{sub 4}){sub 3-x}(GeO{sub 4}){sub x}O, (x=0-3). Black-Right-Pointing-Pointer IR an Raman spectra of mixed crystals.« less

Fesbnd X (X = B, N) binary compounds: First-principles calculations of electronic structures, theoretic hardness and magnetic properties

NASA Astrophysics Data System (ADS)

Hui, Liangliang; Xie, Zhongjing; Li, Chunmei; Chen, Zhi-Qian

2018-04-01

The first-principles calculations are implemented to investigate the electronic structures, theoretic hardness and magnetic properties of iron borides and nitrides with four different crystal systems containing hexagonal (FeB2, ε-Fe3N), tetragonal (Fe2B, α″-Fe16N2), orthorhombic (α-FeB, θ-Fe3B, ζ-Fe2N), and cubic (zb-FeN, rs-FeN, γ‧-Fe4N, γ-Fe23B6) phase. The calculated lattice parameters using RPBE meet well with the experimental results. The cohesive energy and formation enthalpy values indicate the Fesbnd X (X = B, N) binary compounds are thermodynamically stable. Meanwhile, the h-FeB2 is most difficult phase for experimental synthesis among these interstitial compounds. Moreover, magnetic properties are discussed and show that the mean magnetic moments of o-Fe3B and c-Fe23B6 with the values of 2.227 μB and 2.256 μB per iron atom are approaching to that of pure iron (2.32 μB) while the c-Fe4N and t-Fe16N2 with the values of 2.51 and 2.48 μB are beyond that of pure α-Fe. The c-FeN phase shows nonmagnetic in zb-style while rs-type shows antiferromagnetic with a value of 2.52 μB. Furthermore, the average bonding length and Mulliken population combined with electronic structures are also analysed in this paper which provide that strong Fesbnd X and Xsbnd X covalent bonds are responsible for high hardness. Finally, the theoretic hardness of Xsbnd X, Fesbnd X and Fesbnd Fe bonds is predicted by semi empirical hardness theory.

Opportunities for hydrologic research in the Congo Basin

NASA Astrophysics Data System (ADS)

Alsdorf, Douglas; Beighley, Ed; Laraque, Alain; Lee, Hyongki; Tshimanga, Raphael; O'Loughlin, Fiachra; Mahé, Gil; Dinga, Bienvenu; Moukandi, Guy; Spencer, Robert G. M.

2016-06-01

We review the published results on the Congo Basin hydrology and summarize the historic and ongoing research. Annual rainfall is ~1900 mm/yr along an east-west trend across the basin, decreasing northward and southward to ~1100 mm/yr. Historic studies using lysimeters, pans, and models suggest that the annual potential evapotranspiration varies little across the basin at 1100 to 1200 mm/yr. Over the past century, river discharge data have been collected at hundreds of stream gauges with historic and recent data at 96 locations now publicly available. Congo River discharge at Kinshasa-Brazzaville experienced an increase of 21% during the 1960-1970 decade in comparison to most other decades. Satellite altimetry measurements of high and low flows show that water levels in the "Cuvette Centrale" wetland are 0.5 m to 3.0 m higher in elevation than the immediately adjacent Congo River levels. Wetland water depths are shallow at about a meter and there does not appear to be many sizable channels across the "Cuvette"; thus, wetland flows are diffusive. Cuvette waters alone are estimated to emit about 0.5 Pg CH4 and CO2 equivalents/yr, an amount that is significant compared to global carbon evasions. Using these results, we suggest seven hypotheses that focus on the source of the Cuvette waters and how these leave the wetland, on the river discharge generated by historic rainfall, on the connection between climate change and the rainfall-runoff generated by the migrating "tropical rainbelt," on deforestation and hydroelectric power generation, and on the amount of carbon emitted from Congo waters.

Opportunities for Hydrologic Research in the Congo Basin

NASA Astrophysics Data System (ADS)

Alsdorf, D. E.; Beighley, E.; Laraque, A.; Lee, H.; Tshimanga, R.; O'Loughlin, F.; Mahe, G. M.; Dinga, B. J.; Moukandi, G.; Spencer, R.

2016-12-01

We review the published results on the Congo Basin hydrology and summarize the historic and ongoing research. Annual rainfall is 1900 mm/yr along an east-west trend across the basin, decreasing northward and southward to 1100 mm/yr. Historic studies using lysimeters, pans, and models suggest that the annual potential evapotranspiration varies little across the basin at 1100 to 1200 mm/yr. Over the past century, river discharge data have been collected at hundreds of stream gauges with historic and recent data at 96 locations now publicly available. Congo River discharge at Kinshasa-Brazzaville experienced an increase of 21% during the 1960-1970 decade in comparison to most other decades. Satellite altimetry measurements of high and low flows show that water levels in the "Cuvette Centrale" wetland are 0.5m to 3.0m higher in elevation than the immediately adjacent Congo River levels. Wetland water depths are shallow at about a meter and there does not appear to be many sizable channels across the "Cuvette"; thus, wetland flows are diffusive. Cuvette waters alone are estimated to emit about 0.5 Pg CH4 and CO2 equivalents/yr, an amount that is significant compared to global carbon evasions. Using these results, we suggest seven hypotheses that focus on the source of the Cuvette waters and how these leave the wetland, on the river discharge generated by historic rainfall, on the connection between climate change and the rainfall-runoff generated by the migrating "tropical rainbelt," on deforestation and hydroelectric power generation, and on the amount of carbon emitted from Congo waters.

Controllable red, green, blue (RGB) and bright white upconversion luminescence of Lu2O3:Yb3+/Er3+/Tm3+ nanocrystals through single laser excitation at 980 nm.

PubMed

Yang, Jun; Zhang, Cuimiao; Peng, Chong; Li, Chunxia; Wang, Lili; Chai, Ruitao; Lin, Jun

2009-01-01

Light fantastic! Lu(2)O(3):Yb(3+)/Er(3+)/Tm(3+) nanocrystals with controllable red, green, blue (RGB) and bright white upconversion luminescence by a single laser excitation of 980 nm have been successfully synthesized (see picture). Due to abundant UC PL colors, it can potentially be used as fluorophores in the field of color displays, back light, UC lasers, photonics, and biomedicine.Lu(2)O(3):Yb(3+)/Er(3+)/Tm(3+) nanocrystals have been successfully synthesized by a solvothermal process followed by a subsequent heat treatment at 800 degrees C. Powder X-ray diffraction, transmission electron microscopy, upconversion photoluminescence spectra, and kinetic decay were used to characterize the samples. Under single-wavelength diode laser excitation of 980 nm, the bright blue emissions of Lu(2)O(3):Yb(3+), Tm(3+) nanocrystals near 477 and 490 nm were observed due to the (1)G(4)-->(3)H(6) transition of Tm(3+). The bright green UC emissions of Lu(2)O(3):Er(3+) nanocrystals appeared near 540 and 565 nm were observed and assigned to the (2)H(11/2)-->(4)I(15/2) and (4)S(3/2)-->(4)I(15/2) transitions, respectively, of Er(3+). The ratio of the intensity of green luminescence to that of red luminescence decreases with an increase of concentration of Yb(3+) in Lu(2)O(3):Er(3+) nanocrystals. In sufficient quantities of Yb(3+) with resprct to Er(3+), the bright red UC emission of Lu(2)O(3):Yb(3+)/Er(3+) centered at 662 nm was predominant, due to the (4)F(9/2)-->(4)I(15/2) transition of Er(3+). Based on the generation of red, green, and blue emissions in the different doped Lu(2)O(3):RE(3+) nanocrystals, it is possible to produce the luminescence with a wide spectrum of colors, including white, by the appropriate doping of Yb(3+), Tm(3+), and Er(3+) in the present Lu(2)O(3) nanocrystals. Namely, Lu(2)O(3):3 %Yb(3+)/0.2 %Tm(3+)/0.4 %Er(3+) nanocrystals show suitable intensities of blue, green, and red (RGB) emission, resulting in the production of perfect and bright white light

Discharge and other hydraulic measurements for characterizing the hydraulics of Lower Congo River

USGS Publications Warehouse

Oberg, Kevin; Shelton, John M.; Gardiner, Ned; Jackson, P. Ryan

2009-01-01

The first direct measurements of discharge of the Lower Congo River below Malebo Pool and upstream from Kinganga, Democratic Republic of Congo (DRC) were made in July 2008 using acoustic Doppler current profilers, differential GPS, and echo sounders. These measurements were made in support of research that is attempting to understand the distribution of fish species in the Lower Congo River and reasons for separation of species within this large river. Analyses of these measurements show that the maximum depth in the Lower Congo River was in excess of 200 m and maximum water velocities were greater than 4 m/s. The discharge measured near Luozi, DRC was 35,800 m3/s, and decreased slightly beginning midway through the study. Local bedrock controls seem to have a large effect on the flow in the river, even in reaches without waterfalls and rapids. Dramatic changes in bed topography are evident in transects across the river.

A new molecular model for Congo Red-β amyloid interaction: implications for diagnosis and inhibition of brain plaque formation in Alzheimer's disease

NASA Astrophysics Data System (ADS)

Zhang, Kristine A.; Li, Yat

2015-08-01

Alzheimer's disease (AD), an age-related neurodegenerative disorder, is the seventh leading cause of death in the United States. One strong pathological indicator of AD is senile plaques, which are aggregates of fibrils formed from amyloid β (Aβ) peptides. Thus, detection and inhibition of Aβ aggregation are critical for the prevention and treatment of AD. Congo red (CR) is one of the most widely used dye molecules for probing as well as inhabiting Aβ aggregation. However, the nature of interaction between CR and Aβ is not well understood. In this research, we systematically studied the interaction between CR and Aβ using a combination of optical techniques, including electronic absorption, fluorescence, Raman scattering, and circular dichroism, to provide detailed information with molecular specificity and high sensitivity. Compared to CR alone, interaction of the dye with Aβ results in a new absorption peak near 540 nm and significantly enhanced photoluminescence as well as Raman signal. Our results led us to propose a new model suggesting that CR exists primarily in a micellar form, resembling H-aggregates, in water and dissociates into monomers upon interaction with Aβ. This model has significant implications for the development of new strategies to detect and inhibit brain plaques for treatment of neurological diseases like AD.

Collection and Utilization of Animal Carcasses Associated with zoonotic Disease in Tshuapa District, the Democratic Republic of the Congo, 2012.

PubMed

Monroe, Benjamin P; Doty, Jeffrey B; Moses, Cynthia; Ibata, Saturnin; Reynolds, Mary; Carroll, Darin

2015-07-01

The collection and consumption of animal carcasses is a common activity in forested areas of the Congo River basin and creates sustainability, conservation, and health concerns. Residents of the Tshuapa District reported collecting the remains of 5,878 animals from >30 species when surveyed about their wildlife consumption habits. Carcasses were discovered in varying degrees of decomposition and were often consumed at home or sold in local markets. The most commonly collected animals were Cricetomys gambianus (Northern giant pouched rat), Cercopithecus ascanius (red-tailed monkey), and Heliosciurus rufobrachium (red-legged sun squirrel). Many of the species recorded may be hosts of zoonotic pathogens, creating concern for spillover events.

Congo Basin precipitation: Assessing seasonality, regional interactions, and sources of moisture

NASA Astrophysics Data System (ADS)

Dyer, Ellen L. E.; Jones, Dylan B. A.; Nusbaumer, Jesse; Li, Harry; Collins, Owen; Vettoretti, Guido; Noone, David

2017-07-01

Precipitation in the Congo Basin was examined using a version of the National Center for Atmospheric Research Community Earth System Model (CESM) with water tagging capability. Using regionally defined water tracers, or tags, the moisture contribution from different source regions to Congo Basin precipitation was investigated. We found that the Indian Ocean and evaporation from the Congo Basin were the dominant moisture sources and that the Atlantic Ocean was a comparatively small source of moisture. In both rainy seasons the southwestern Indian Ocean contributed about 21% of the moisture, while the recycling ratio for moisture from the Congo Basin was about 25%. Near the surface, a great deal of moisture is transported from the Atlantic into the Congo Basin, but much of this moisture is recirculated back over the Atlantic in the lower troposphere. Although the southwestern Indian Ocean is a major source of Indian Ocean moisture, it is not associated with the bulk of the variability in precipitation over the Congo Basin. In wet years, more of the precipitation in the Congo Basin is derived from Indian Ocean moisture, but the spatial distribution of the dominant sources is shifted, reflecting changes in the midtropospheric circulation over the Indian Ocean. During wet years there is increased transport of moisture from the equatorial and eastern Indian Ocean. Our results suggest that reliably capturing the linkages between the large-scale circulation patterns over the Indian Ocean and the local circulation over the Congo Basin is critical for future projections of Congo Basin precipitation.

Optical spectroscopy and magnetic behaviour of Sm3+ and Eu3+ cations in Li6Eu1-xSmx(BO3)3 solid solution

NASA Astrophysics Data System (ADS)

Belhoucif, Rekia; Velázquez, Matias; Plantevin, Olivier; Aschehoug, Patrick; Goldner, Philippe; Christian, George

2017-11-01

A new borate solid solution series of powders, Li6Eu1-xSmx(BO3)3 (LSEBx, x = 0.35, 0.5, 0.6, 1), were synthesized by solid-state reaction, characterized and their luminescent properties were investigated. The absorption spectra indicate that absorption takes place mainly from the Sm3+6H5/2 ground state, with a strong band at 405 nm. The photoluminescence spectra reveal that the Eu3+ red emission intensity strongly depends on the Sm3+ content x. Judd-Ofelt theory was applied to experimental data for the quantitative determination of phenomenological parameters Ωi (i = 2, 4, 6) Judd Ofelt parameters, radiative transition rates and emission quantum efficiency. Owing to the energy transfer from Sm3+ to Eu3+ the intense red light detected at 613 nm at room temperature under UV or blue light excitation, was improved by ∼35% as compared with Sm3+-free samples. This energy transfer was confirmed by faster decay times of Sm3+ as energy donors. Moreover, the energy transfer between Sm3+ and Eu3+ is unidirectional and irreversible, implying that the energy transfer wastage between Sm3+ and Eu3+ is very low. Magnetic susceptibility (χ) measurements of LSEBx were carried out in the temperature range 2-320 K and are used to compare calculated and experimental energy levels.

Biosorption potential of synthetic dyes by heat-inactivated and live Lentinus edodes CCB-42 immobilized in loofa sponges.

PubMed

Gimenez, Gabriela Gregolin; Ruiz, Suelen Pereira; Caetano, Wilker; Peralta, Rosane Marina; Matioli, Graciette

2014-12-01

Lentinus edodes CCB-42 was immobilized in loofa sponges and applied to the biosorption of the synthetic dyes congo red, bordeaux red and methyl violet. Live immobilized microorganisms achieved average decolorations of congo red, bordeaux red and methyl violet of 97.8, 99.7 and 90.6 %, respectively. The loofa sponge was the support and the coadjuvant promoting dye adsorption. The biosorption conditions were optimized for each dye, yielding 30 °C, pH 5.0 and a 12 h reaction time for congo red; 25 °C, pH 3.0 and 36 h for bordeaux red; and 25 °C, pH 8.0 and 24 h for methyl violet. Operational stability was evaluated over five consecutive cycles, with both bordeaux red and congo red exhibiting decolorations above 90 %, while the decoloration of methyl violet decreased after the third cycle. In the sixth month of storage, congo red, bordeaux red and methyl violet had decolorations of 93.1, 79.4 and 73.8 %, respectively. Biosorption process best fit the pseudo-second-order kinetic and Freundlich isotherm models. Maximum biosorption capacity of heat-treated L. edodes immobilized in loofa sponge was determined as 143.678, 500.00 and 381.679 mg/g for congo red, bordeaux red and methyl violet, respectively. Treatment with immobilized L. edodes reduced the phytotoxicity of the medium containing dyes. FT-Raman experiments suggested the occurrence of interactions between loofa sponge fibers, L. edodes and dye. L. edodes CCB-42 immobilized in loofa sponges represents a promising new mode of treatment of industrial effluents.

The restoration in vivo of 2,3-diphosphoglycerate (2,3-DPG) in stored red cells, after transfusion. The levels of red cells 2,3-DPG.

PubMed

Stan, Ana; Zsigmond, Eva

2009-01-01

Since the main reason for transfusing preserved red cells is to increase the oxygen carrying capacity of the recipient, the circulating preserved red cells should have at the time of transfusion normal oxygen uptake and normal oxyhemoglobin dissociation characteristics. We evaluated the effectiveness of transfused red cells, through periodical determination of erythrocyte components, during 72 hours after transfusions of large quantities (3,000 mL) of blood. Three patients with massive hemorrhages, two after amputation and one after nephrectomy were given each 3,000 mL preserved blood (in ACD, 10 days, at 4 degrees C). Red cell 2,3-DPG and serum inorganic phosphorus were determined prior to transfusion and after, periodically, for three days. Red cell 2,3-DPG was determined by Krimsky's method and inorganic phosphorus by Kuttner and Lichtenstein's method. The in vivo restoration of 2,3-DPG--of transfused red cells is shown as a percentage of recipient's final 2,3-DPG level, and was calculated in each of the three patients. The level of erythrocyte 2,3-DPG was greater than 60% of the final level within 24 hours, after the end of transfusion. The in vivo rates of restoration of 2,3-DPG in transfused red cells for periods of 0-6, 6-24, 24-48 and 48-72 hours are 0.251, 0.238, 0.133, 0.120 mM/L cells/hour. The therapeutic significance of the increased oxygen affinity of stored blood becomes very important in clinical conditions, when large volumes of red cells are urgently needed. After massive transfusions, the restoration of 2,3-DPG in red cells produces a decrease of serum inorganic phosphorus through its consumption. The stored blood with low values of erythrocyte 2,3-DPG can be used without hesitation when correcting a chronic anemia for instance, but in acute situation, when the organism needs restoration of the oxygen releasing capacity within minutes, the resynthesis is obviously insufficient. In such situations, fresh blood or blood with a near normal 2,3-DPG

An evaluation of the rate of absorption of solar radiation in the O2(X3Sigma-g - b1Sigma-g) transition

NASA Technical Reports Server (NTRS)

Mlynczak, Martin G.

1993-01-01

The rate at which molecular oxygen absorbs radiation in the O2(X3Sigma-g - b1Sigma-g) transition is calculated using a line-by-line radiative transfer model. This rate is critical to the determination of the population of the O2(b1Sigma-g) state required for studies of the O2(b1Sigma-g - X3Sigma-g) dayglow, the O2(a1Delta-g - X3Sigma-g) dayglow, and possibly the rates of oxidation of H2 and N2O. Previous evaluations of this rate (which is sometimes called the g-factor) have significantly overestimated its value. The rate is tabulated as a function of altitude, pressure, and solar zenith angle.

Formation, stability and crystal structure of mullite-type Al{sub 6−x}B{sub x}O{sub 9}

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

Hoffmann, K., E-mail: Kristin.Hoffmann@uni-bremen.de; Institut für Anorganische Chemie und Kristallographie, FB02, Leobener Straße/NW2, Universität Bremen, D-28359 Bremen; Hooper, T.J.N.

2016-11-15

Mullite-type Al{sub 6−x}B{sub x}O{sub 9} compounds were studied by means of powder diffraction and spectroscopic methods. The backbones of this structure are chains of edge-connected AlO{sub 6} octahedra crosslinked by AlO- and BO-polyhedra. Rietveld refinements show that the a and b lattice parameters can be well resolved, thus representing an orthorhombic metric. A continuous decrease of the lattice parameters most pronounced in c-direction indicates a solid solution for Al{sub 6−x}B{sub x}O{sub 9} with 1.09≤x≤2. A preference of boron in 3-fold coordination is confirmed by {sup 11}B MAS NMR spectroscopy and Fourier calculations based on neutron diffraction data collected at 4more » K. Distance Least Squares modeling was performed to simulate a local geometry avoiding long B-O distances linking two octahedral chains by planar BO{sub 3} groups yielding split positions for the oxygen atoms and a strong distortion in the octahedral chains. The lattice thermal expansion was calculated using the Grüneisen first-order equation of state Debye-Einstein-Anharmonicity model. - Graphical abstract: Local distortion induced by boron linking the octahedral chains. - Highlights: • Decreasing lattice parameters indicate a solid solution for Al{sub 6−x}B{sub x}O{sub 9} (1.09≤x≤2). • B-atoms induce a local distortion of neighboring AlO{sub 6} octahedra. • A preference of boron in BO{sub 3} coordination is confirmed by {sup 11}B MAS NMR spectroscopy. • An optimized structural model for Al{sub 6−x}B{sub x}O{sub 9} is presented.« less

High-Resolution Laser Spectroscopy of the tilde{B} ← tilde{X} Transition of 14NO3 Radical: Vibrationally Excited States of the tilde{B} State

NASA Astrophysics Data System (ADS)

Kasahara, Shunji; Tada, Kohei; Hirata, Michihiro; Ishiwata, Takashi; Hirota, Eizi

2016-06-01

Rotationally-resolved high-resolution fluorescence excitation spectra of the tilde{B} 2E' ← tilde{X} 2A2' electronic transition of 14NO3 radical have been observed for 15860-15920 cm-1 region. Sub-Doppler excitation spectra were measured by crossing a single-mode laser beam perpendicular to a collimated radical beam, which was formed by the heat decomposition of 14N2O5; 14N2O5 → 14NO3 + 14NO2. We have also measured the high-resolution fluorescence excitation spectra of the 14NO2 tilde{A} 2B{2} ← tilde{X} 2A1 transition to distinguish the 14NO3 signals from the 14NO2 signals in the observed region. The typical linewidth was 30 MHz and the absolute wavenumber was calibrated with accuracy 0.0001 cm-1 by measurement of the Doppler-free saturation spectrum of iodine molecule and fringe pattern of the stabilized etalon. The observed rotational lines were too complicated to find any rotational series. In the observed spectra, only the rotational line pairs from the tilde{X} 2A2'(v''=0, K''=0, N''=1, F1 and F2) levels are assigned unambiguously by using the combination differences of the tilde{X} 2A2' state and measurement of the Zeeman splittings similar to the analysis of the 0-0 band at around 15100 cm-1 region. The observed results suggest the observed vibrationally excited states of the tilde{B} 2E' state are also interacts with the other vibronic levels similar to the tilde{B} 2E'(v'=0) level. K. Tada, W. Kashihara, M. Baba, T. Ishiwata, E. Hirota, and S. Kasahara, J. Chem. Physc. 141, 184307 (2014). K. Tada, T. Ishiwata, E. Hirota, and S. Kasahara, J. Mol. Spectrosc., 321, 23 (2016)

In situ X-ray fluorescence-based method to differentiate among red ochre pigments and yellow ochre pigments thermally transformed to red pigments of wall paintings from Pompeii.

PubMed

Marcaida, Iker; Maguregui, Maite; Fdez-Ortiz de Vallejuelo, Silvia; Morillas, Héctor; Prieto-Taboada, Nagore; Veneranda, Marco; Castro, Kepa; Madariaga, Juan Manuel

2017-06-01

Most of the magnificent wall paintings from the ancient city of Pompeii are decorated with red and yellow colors coming from the ochre pigments used. The thermal impact of the pyroclastic flow from the eruption of Vesuvius, in AD 79, promoted the transformation of some yellow painted areas to red. In this work, original red ochre, original yellow ochre, and transformed yellow ochre (nowadays showing a red color) of wall paintings from Pompeian houses (House of Marcus Lucretius and House of Gilded Cupids) were analyzed by means of a handheld energy-dispersive X-ray fluorescence spectrometer to develop a fast method that allows chemical differentiation of the original red ochre and the transformed yellow ochre. Principal component analysis of the multivariate obtained data showed that arsenic is the tracer element to distinguish between both red colored ochres. Moreover, Pompeian raw red and yellow ochre pigments recovered from the burial were analyzed in the laboratory with use of a benchtop energy-dispersive X-ray fluorescence spectrometer to confirm the elemental composition and the conclusions drawn from the in situ analysis according to the yellow ochre pigment transformation in real Pompeian wall paintings.

Tailoring CD19xCD3-DART exposure enhances T-cells to eradication of B-cell neoplasms.

PubMed

Circosta, Paola; Elia, Angela Rita; Landra, Indira; Machiorlatti, Rodolfo; Todaro, Maria; Aliberti, Sabrina; Brusa, Davide; Deaglio, Silvia; Chiaretti, Sabina; Bruna, Riccardo; Gottardi, Daniela; Massaia, Massimo; Giacomo, Filomena Di; Guarini, Anna Rita; Foà, Robin; Kyriakides, Peter W; Bareja, Rohan; Elemento, Olivier; Chichili, Gurunadh R; Monteleone, Emanuele; Moore, Paul A; Johnson, Syd; Bonvini, Ezio; Cignetti, Alessandro; Inghirami, Giorgio

2018-01-01

Many patients with B-cell malignancies can be successfully treated, although tumor eradication is rarely achieved. T-cell-directed killing of tumor cells using engineered T-cells or bispecific antibodies is a promising approach for the treatment of hematologic malignancies. We investigated the efficacy of CD19xCD3 DART bispecific antibody in a broad panel of human primary B-cell malignancies. The CD19xCD3 DART identified 2 distinct subsets of patients, in which the neoplastic lymphocytes were eliminated with rapid or slow kinetics. Delayed responses were always overcome by a prolonged or repeated DART exposure. Both CD4 and CD8 effector cytotoxic cells were generated, and DART-mediated killing of CD4 + cells into cytotoxic effectors required the presence of CD8 + cells. Serial exposures to DART led to the exponential expansion of CD4 + and CD8 + cells and to the sequential ablation of neoplastic cells in absence of a PD-L1-mediated exhaustion. Lastly, patient-derived neoplastic B-cells (B-Acute Lymphoblast Leukemia and Diffuse Large B Cell Lymphoma) could be proficiently eradicated in a xenograft mouse model by DART-armed cytokine induced killer (CIK) cells. Collectively, patient tailored DART exposures can result in the effective elimination of CD19 positive leukemia and B-cell lymphoma and the association of bispecific antibodies with unmatched CIK cells represents an effective modality for the treatment of CD19 positive leukemia/lymphoma.

Effect of molybdenum on gamma ray shielding and structural properties of PbO-B2O3 glasses

NASA Astrophysics Data System (ADS)

Dogra, Mridula; Singh, K. J.; Kaur, Kulwinder

2018-04-01

The present study is aimed at developing new shielding materials for gamma ray shielding applications. Transparent glasses of the composition xMoO3-0.7PbO-(0.3-x)B2O3 where x= 0.03 to 0. 06 (mole fraction) have been prepared by using melt-quenchingtechnique. Gamma ray shielding properties have been evaluated in terms of mass attenuation coefficient and half value layer parameter at photon energies 662 and 1173 keV. These shielding parameters are also compared with standard shielding material`concretes'. It has been found that prepared glass system shows better shielding properties than barite and ordinary concretes proving the possibility of its usage as an alternate to conventional concrete for gamma ray shielding applications. The density, molar volume, X-Ray Diffraction, Fourier Transform InfraRed and Raman studies have been performed to study the structural properties of the glass system. It has been analyzed from FTIR and Raman studies that bridging oxygens increase with the decrease of MoO3 content in the glass composition.

Paleomagnetism of the 765 Ma Luakela Volcanics in NW Zambia and Implications for Neoproterozoic Positions of the Congo Craton

NASA Astrophysics Data System (ADS)

Wingate, M. T.; Pisarevsky, S. A.; de Waele, B.

2004-12-01

Owing to the scarcity of reliable paleopoles, the Neoproterozoic position of the Congo craton (incorporating the Sao Francisco, Tanzania, and Bangweulu blocks) is very poorly known. We report new paleomagnetic data for the 765 ± 5 Ma Luakela volcanics, a NE-trending belt of basaltic to andesitic flows in NW Zambia (Key et al., 2001, J. Afr. Earth Sci., 33, 503-528). The volcanics are up to 0.8 km thick and occur within a 2 km thick succession of siliciclastic rocks that unconformably overlies Neoarchean and Paleoproterozoic rocks of the Congo craton margin, and is correlated with the Roan and Mwashia Groups of the Katanga Supergroup (Key et al., 2001). The strata are essentially undeformed, and either subhorizontal or dip shallowly to the SE. Although no metamorphic mineral growth is observed in fine-grained sedimentary rocks, alteration has strongly affected plagioclase and pyroxene in the volcanic rocks, and magnetite has been partially altered to hematite (Key et al., 2001). AF and thermal analysis of 65 samples from nine sites isolated three magnetisation components. Component A, carried mainly by SD magnetite, is directed very shallowly to the SE. Component B, carried mainly by hematite, is oriented shallowly SW-up. A low stability component C is directed very steeply downward. Some samples contain only component A, others only component B, and some contain both A and B. Component A is likely to be primary, because it is carried by SD magnetite (which petrography indicates is primary), does not resemble younger magnetisations from the Congo craton, and because the rocks have not been thermally metamorphosed. Component B, carried by hematite, we consider to be an overprint, possibly acquired during Pan-African deformation in the Lufilian Arc. Component C is similar to Permo-Carboniferous paleodirections from the region, and may have been acquired at that time. Paleopoles for components A and B (LVA and LVB) are about 90° apart, and similar to those from the

Serosurvey for Crimean-Congo hemorrhagic fever virus infections in ruminants in Katanga province, Democratic Republic of the Congo.

PubMed

Sas, Miriam A; Mertens, Marc; Kadiat, Jean G; Schuster, Isolde; Pongombo, Célestin P S; Maloba, Alois G K; Groschup, Martin H

2017-10-01

Crimean-Congo hemorrhagic fever virus (CCHFV) has been detected in many African countries. Unfortunately, little is known about the current CCHFV situation in most of those countries including the Democratic Republic of the Congo (DRC). In over 50 years, three human CCHF cases have been detected in DRC but no seroepidemiological investigation was performed so far. To determine the prevalence of CCHFV-specific antibodies we tested 838 serum samples of cattle, goat and sheep from the southern province Katanga, DRC. The detected seroprevalence in ruminants was 1.6% ranging from 0.4% to 3.4% between the two sampling sites, Kamina and Lubumbashi. The low prevalence indicates only sporadic introduction of CCHFV into this part of the country. DRC is a very large country and the study was performed only at two locations in one province; therefore, the investigations can be only a starting point for further epidemiological activities. Copyright © 2017 Elsevier GmbH. All rights reserved.

Unique and hierarchically structured novel Co3O4/NiO nanosponges with superior photocatalytic activity against organic contaminants

NASA Astrophysics Data System (ADS)

Raja, Vahini; Puvaneswaran, Senthil Kumar; Swaminathan, Karuthapandian

2017-12-01

In the present study, novel Co3O4/NiO nanosponges designed for the photocatalytic degradation of organic contaminants were synthesized by a simple precipitation technique. The formation of sponge-like nanostructures was clearly evident through the TEM analysis. The photocatalytic efficiency was tested against rhodamine B (RhB) and congo red (CR) dye solutions. Co3O4/NiO nanosponges showed excellent and enhanced photocatalytic efficacy compared to those of Co3O4, NiO nanoparticles, and standards like TiO2 and ZnO. The influence of paramount important operational parameters was explored and the conditions for the best photocatalytic efficiency were optimized. The trapping experiment revealed that the reactive oxygen species (ROS) identified was OH radical. These findings certainly open up a new way for synthesizing a morphology dependent photocatalyst.

Congo crimean hemorrhagic Fever in balochistan.

PubMed

Durrani, Abdul Baqi; Shaikh, Muzaffar; Khan, Zahir

2007-09-01

To observe the pattern and mortality of Congo-Crimean Hemorrhagic Fever (CCHF) in Balochistan. Case series. Department of Medicine, Sandeman Provincial Hospital and Bolan Medical Complex Hospital, Quetta, from September, 1995 to August, 2005. Two hundred and twenty-six febrile patients with bleeding of sudden onset, with initial signs and symptoms including headache, high fever, back pain, joint pain, stomach pain, vomiting, red eyes, flushed face, red throat and petechiae on the palate of both sexes were screened for CCHF over a period of 10 years. Clinical criteria for initial diagnosis directed the subsequent diagnostic work-up. The ages of these patients ranged from 7 years to 74 years. Sixty-three percent of these patients were positive for CCHF. Males were 68% of the total patients. Over the years, CCHF showed a gradual increase ranging from 43% to 80%. Total mortality was 15%, all being secondary cases. Death was not observed in primary CCHF cases. In this study, suspicion of viral hemorrhagic fever was raised in 62% cases at the time of admission and the patients were immediately isolated, noninvasive procedures were instigated and barrier nursing was implemented. None of the family and hospital staff members who had close contact with the patient became ill, while those who were not suspected initially (38%) infected the health care workers and the family members. Although CCHF is rare, this study stresses the need for proper health facilities in Pakistan and to include VHF (viral hemorrhagic fevers) in the differential diagnosis of unexplained fever with hemorrhagic tendencies of sudden onset.

Head Lice of Pygmies Reveal the Presence of Relapsing Fever Borreliae in the Republic of Congo.

PubMed

Amanzougaghene, Nadia; Akiana, Jean; Mongo Ndombe, Géor; Davoust, Bernard; Nsana, Nardiouf Sjelin; Parra, Henri-Joseph; Fenollar, Florence; Raoult, Didier; Mediannikov, Oleg

2016-12-01

Head lice, Pediculus humanus capitis, occur in four divergent mitochondrial clades (A, B, C and D), each having particular geographical distributions. Recent studies suggest that head lice, as is the case of body lice, can act as a vector for louse-borne diseases. Therefore, understanding the genetic diversity of lice worldwide is of critical importance to our understanding of the risk of louse-borne diseases. Here, we report the results of the first molecular screening of pygmies' head lice in the Republic of Congo for seven pathogens and an analysis of lice mitochondrial clades. We developed two duplex clade-specific real-time PCRs and identified three major mitochondrial clades: A, C, and D indicating high diversity among the head lice studied. We identified the presence of a dangerous human pathogen, Borrelia recurrentis, the causative agent of relapsing fever, in ten clade A head lice, which was not reported in the Republic of Congo, and B. theileri in one head louse. The results also show widespread infection among head lice with several species of Acinetobacter. A. junii was the most prevalent, followed by A. ursingii, A. baumannii, A. johnsonii, A. schindleri, A. lwoffii, A. nosocomialis and A. towneri. Our study is the first to show the presence of B. recurrentis in African pygmies' head lice in the Republic of Congo. This study is also the first to report the presence of DNAs of B. theileri and several species of Acinetobacter in human head lice. Further studies are needed to determine whether the head lice can transmit these pathogenic bacteria from person to another.

Blue and Red Light Modulates SigB-Dependent Gene Transcription, Swimming Motility and Invasiveness in Listeria monocytogenes

PubMed Central

Ondrusch, Nicolai; Kreft, Jürgen

2011-01-01

Background In a number of gram-positive bacteria, including Listeria, the general stress response is regulated by the alternative sigma factor B (SigB). Common stressors which lead to the activation of SigB and the SigB-dependent regulon are high osmolarity, acid and several more. Recently is has been shown that also blue and red light activates SigB in Bacillus subtilis. Methodology/Principal Findings By qRT-PCR we analyzed the transcriptional response of the pathogen L. monocytogenes to blue and red light in wild type bacteria and in isogenic deletion mutants for the putative blue-light receptor Lmo0799 and the stress sigma factor SigB. It was found that both blue (455 nm) and red (625 nm) light induced the transcription of sigB and SigB-dependent genes, this induction was completely abolished in the SigB mutant. The blue-light effect was largely dependent on Lmo0799, proving that this protein is a genuine blue-light receptor. The deletion of lmo0799 enhanced the red-light effect, the underlying mechanism as well as that of SigB activation by red light remains unknown. Blue light led to an increased transcription of the internalin A/B genes and of bacterial invasiveness for Caco-2 enterocytes. Exposure to blue light also strongly inhibited swimming motility of the bacteria in a Lmo0799- and SigB-dependent manner, red light had no effect there. Conclusions/Significance Our data established that visible, in particular blue light is an important environmental signal with an impact on gene expression and physiology of the non-phototrophic bacterium L. monocytogenes. In natural environments these effects will result in sometimes random but potentially also cyclic fluctuations of gene activity, depending on the light conditions prevailing in the respective habitat. PMID:21264304

Lamprologus markerti, a new lamprologine cichlid (Teleostei: Cichlidae) endemic to the lower Congo River in the Democratic Republic of Congo, west-central Africa.

PubMed

Tougas, Stephanie; Stiassny, Melanie L J

2014-08-15

A new Lamprologus is described from the lower Congo River (LCR) in the Democratic Republic of Congo. Lamprologus markerti, new species, is readily distinguished from L. tigripictilis and L. werneri, the LCR endemic lamprologines with which it was once taxonomically conflated, in the possession of a reduced number of gill rakers on the first arch (9-11 versus 12-17), a longer head (32.1-34.7% SL versus 29.3-31.9 and 29.1-32.9% SL, respectively), and a longer predorsal length (33.0-35.9% SL versus 29.3-32.7 and 28.5-32.6% SL, respectively). Further, L. markerti lacks a second intestinal loop present in both L. tigripictilis and L. werneri, and has a highly reduced infraorbital series often consisting of a single first infraorbital (lachrymal) element. 

Y-chromosomal variation in sub-Saharan Africa: insights into the history of Niger-Congo groups.

PubMed

de Filippo, Cesare; Barbieri, Chiara; Whitten, Mark; Mpoloka, Sununguko Wata; Gunnarsdóttir, Ellen Drofn; Bostoen, Koen; Nyambe, Terry; Beyer, Klaus; Schreiber, Henning; de Knijff, Peter; Luiselli, Donata; Stoneking, Mark; Pakendorf, Brigitte

2011-03-01

Technological and cultural innovations as well as climate changes are thought to have influenced the diffusion of major language phyla in sub-Saharan Africa. The most widespread and the richest in diversity is the Niger-Congo phylum, thought to have originated in West Africa ∼ 10,000 years ago (ya). The expansion of Bantu languages (a family within the Niger-Congo phylum) ∼ 5,000 ya represents a major event in the past demography of the continent. Many previous studies on Y chromosomal variation in Africa associated the Bantu expansion with haplogroup E1b1a (and sometimes its sublineage E1b1a7). However, the distribution of these two lineages extends far beyond the area occupied nowadays by Bantu-speaking people, raising questions on the actual genetic structure behind this expansion. To address these issues, we directly genotyped 31 biallelic markers and 12 microsatellites on the Y chromosome in 1,195 individuals of African ancestry focusing on areas that were previously poorly characterized (Botswana, Burkina Faso, Democratic Republic of Congo, and Zambia). With the inclusion of published data, we analyzed 2,736 individuals from 26 groups representing all linguistic phyla and covering a large portion of sub-Saharan Africa. Within the Niger-Congo phylum, we ascertain for the first time differences in haplogroup composition between Bantu and non-Bantu groups via two markers (U174 and U175) on the background of haplogroup E1b1a (and E1b1a7), which were directly genotyped in our samples and for which genotypes were inferred from published data using linear discriminant analysis on short tandem repeat (STR) haplotypes. No reduction in STR diversity levels was found across the Bantu groups, suggesting the absence of serial founder effects. In addition, the homogeneity of haplogroup composition and pattern of haplotype sharing between Western and Eastern Bantu groups suggests that their expansion throughout sub-Saharan Africa reflects a rapid spread followed by

Fluorescence properties of Tb{sup 3+} and Sm{sup 3+} activated novel LiAl{sub 7}B{sub 4}O{sub 17} host via solution combustion synthesis

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

Palaspagar, R.S., E-mail: rspalaspagar@gmail.com; Gawande, A.B., E-mail: gawandeab@gmail.com; Sonekar, R.P., E-mail: sonekar_rp@yahoo.com

2015-12-15

Graphical abstract: - Highlights: • New LiAl{sub 7}B{sub 4}O{sub 17}:Tb{sup 3+}, Sm{sup 3+} phosphors were synthesized first time by solution combustion method. • The LiAl{sub 7}B{sub 4}O{sub 17}:Tb{sup 3+} emissions; 489, 544, 586 and 623 nm (λ{sub ex} = 234 nm). • Also for LiAl{sub 7}B{sub 4}O{sub 17}:Sm{sup 3+}; 564, 601 and 649 nm (λ{sub ex} = 403 nm). • Synthesized materials were characterized by powder XRD, FE-SEM. • Concentration quenching mechanism and critical transfer distance of Tb{sup 3+} and Sm{sup 3+} in the prepared sample has been investigated. - Abstract: Novel LiAl{sub 7}B{sub 4}O{sub 17} (LABO) phosphor activated withmore » trivalent rare earth ions (RE = Tb, Sm) was synthesized by using solution combustion synthesis. The powder X-ray diffraction (XRD), field emission-scanning electron microscope (FE-SEM), photoluminescence (PL), critical transfer distance (R{sub c}) and quenching mechanism studies were employed to characterize the samples. Under ultraviolet irradiation of the LiAl{sub 7}B{sub 4}O{sub 17}: Tb{sup 3+}, Sm{sup 3+} phosphors exhibit the typical green ({sup 5}D{sub 4} → {sup 7}F{sub j} = 6, 5, 4 and 3) emission band of the Tb{sup 3+} ions, as well as an orange-red and red ({sup 4}G{sub 5/2} → {sup 6}H{sub J=5/2,} {sub 7/2,} {sub 9/2}) emission bands of the Sm{sup 3+} ions. These results suggest that Tb{sup 3+} and Sm{sup 3+} activated LABO phosphor could be promising in vision of the necessity for solid state lighting applications.« less

Determination of the rate constant for the NH2(X(2)B1) + NH2(X(2)B1) reaction at low pressure and 293 K.

PubMed

Bahng, Mi-Kyung; Macdonald, R Glen

2008-12-25

The rate constant for the reaction NH(2)(X(2)B(1)) + NH(2)(X(2)B(1)) --> products was measured in CF(4), N(2) and Ar carrier gases at 293 +/- 2 K over a pressure range from 2 to 10 Torr. The NH(2) radical was produced by the 193 nm photolysis of NH(3) dilute in the carrier gas. Both the loss of NH(3) and its subsequent recovery and the production of NH(2) and subsequent reaction were monitored simultaneously following the photolysis laser pulse. Both species were detected using quantitative time-resolved high-resolution absorption spectroscopy. The NH(3) molecule was monitored in the NIR using a rotation transition of the nu(1) + nu(3) first combination band near 1500 nm, and the NH(2) radical was monitored using the (1)2(21) <-- (1)3(31) rotational transition of the (0,7,0)A(2)A(1) <-- (0,0,0) X(2)B(1) band near 675 nm. The low-pressure rate constant showed a linear dependence on pressure. The slope of the pressure dependence was dominated by a recombination rate constant for NH(2) + NH(2) given by (8.0 +/- 0.5) x 10(-29), (5.7 +/- 0.7) x 10(-29), and (3.9 +/- 0.4) x 10(-29) cm(6) molecule(-2) s(-1) in CF(4), N(2), and Ar bath gases, respectively, where the uncertainties are +/-2sigma in the scatter of the measurements. The average of the three independent measurements of the sum of the disproportionation rate constants (the zero pressure rate constant) was (3.4 +/- 6) x 10(-13) cm(3) molecule(-1) s(-1), where the uncertainty is +/-2sigma in the scatter of the measurements.

Measurement of sigma Lambda b0/sigma B0 x B(Lambda b0-->Lambda c+pi-)/B(B0-->D+pi-) in pp collisions at square root s=1.96 TeV.

PubMed

Abulencia, A; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Ambrose, D; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arguin, J-F; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Bedeschi, F; Behari, S; Belforte, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Budroni, S; Burkett, K; Busetto, G; Bussey, P; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carillo, S; Carlsmith, D; Carosi, R; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Ciljak, M; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Coca, M; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Cully, J C; Cyr, D; DaRonco, S; D'Auria, S; Davies, T; D'Onofrio, M; Dagenhart, D; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; Dell'Orso, M; Delli Paoli, F; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; DiTuro, P; Dörr, C; Donati, S; Donega, M; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Field, R; Flanagan, G; Foland, A; Forrester, S; Foster, G W; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garcia, J E; Garberson, F; Garfinkel, A F; Gay, C; Gerberich, H; Gerdes, D; Giagu, S; Giannetti, P; Gibson, A; Gibson, K; Gimmell, J L; Ginsburg, C; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Griffiths, M; Grinstein, S; Grosso-Pilcher, C; Group, R C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Holloway, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ishizawa, Y; Ivanov, A; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jensen, H; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kovalev, A; Kraan, A C; Kraus, J; Kravchenko, I; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Le, Y; LeCompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Loverre, P; Lu, R-S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; MacQueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Manca, G; Margaroli, F; Marginean, R; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Maruyama, T; Mastrandrea, P; Masubuchi, T; Matsunaga, H; Mattson, M E; Mazini, R; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyamoto, A; Moed, S; Moggi, N; Mohr, B; Moore, R; Morello, M; Movilla Fernandez, P; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Nachtman, J; Nagano, A; Naganoma, J; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nigmanov, T; Nodulman, L; Norniella, O; Nurse, E; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Oldeman, R; Orava, R; Osterberg, K; Pagliarone, C; Palencia, E; Papadimitriou, V; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ranjan, N; Rappoccio, S; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Sabik, S; Safonov, A; Sakumoto, W K; Salamanna, G; Saltó, O; Saltzberg, D; Sánchez, C; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savard, P; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyrla, A; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Sjolin, J; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Spreitzer, T; Squillacioti, P; Stanitzki, M; Staveris-Polykalas, A; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sun, H; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Takikawa, K; Tanaka, M; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tseng, J; Tsuchiya, R; Tsuno, S; Turini, N; Ukegawa, F; Unverhau, T; Uozumi, S; Usynin, D; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Veramendi, G; Veszpremi, V; Vidal, R; Vila, I; Vilar, R; Vine, T; Vollrath, I; Volobouev, I; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner, J; Wagner, W; Wallny, R; Wang, S M; Warburton, A; Waschke, S; Waters, D; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zhou, J; Zucchelli, S

2007-03-23

We present the first observation of the baryon decay Lambda b0-->Lambda c+pi- followed by Lambda c+-->pK-pi+ in 106 pb-1 pp collisions at square root s=1.96 TeV in the CDF experiment. In order to reduce systematic error, the measured rate for Lambda b0 decay is normalized to the kinematically similar meson decay B0-->D+pi- followed by D+-->pi+K-pi+. We report the ratio of production cross sections (sigma) times the ratio of branching fractions (B) for the momentum region integrated above pT>6 GeV/c and pseudorapidity range |eta|<1.3: sigma(pp-->Lambda b0X)/sigma(pp-->B0X)xB(Lambda b0-->Lambda c+pi-)/B(B0-->D+pi-)=0.82+/-0.08(stat)+/-0.11(syst)+/-0.22[B(Lambda c+-->pK-pi+)].

Spin-split fermi surfaces in CexLa1-xB6 and PrxLa1-xB6

NASA Astrophysics Data System (ADS)

Isshiki, T.; Endo, M.; Sugi, M.; Kimura, N.; Nakamura, S.; Nojima, T.; Aoki, H.; Kunii, S.

2006-05-01

We have performed the dHvA measurements on CexLa1-xB6 and PrxLa1-xB6 compounds to study spin splitting of the Fermi surfaces. In PrB 6 we have found new frequency branches to confirm that the Fermi surface splits into up and down spin Fermi surfaces, whereas no spin splitting has been found for x=0.25,0.5,0.75. We have also found several new frequency branches in CeB6. The new frequency branches imply that the Fermi surfaces of up and down spin conduction electrons are significantly different in CeB6 as well as in PrB6.

Investigations on optical properties of Eu3+ ion doped magnesium telluroborate glasses for red laser applications

NASA Astrophysics Data System (ADS)

Arunkumar, S.; Annapoorani, K.; Marimuthu, K.

2018-04-01

Eu3+ doped Magnesium telluroborate glasses were prepared with the chemical composition (40-x)H3BO3+35 TeO2+15MgCO3+10MgF2+xEu2O3 (where x = 0.1, 0.5, 1.0 and 2.0 in wt%) following the melt quenching technique and labeled as MTB0.1Eu, MTB0.5Eu, MTB1.0Eu and MTB2.0Eu respectively. The absorption spectra exhibit seven peaks in the visible and NIR region. Five emission peaks corresponding to the 5D0→7FJ (J=0, 1, 2, 3, 4) transitions were observed while exciting at 465 nm. The luminescence intensity ratio (R) and Ω2 parameter values were found to be higher for the MTB0.5Eu glass thus indicates the higher asymmetry around the Eu3+ ions site compared to other prepared glasses. The CIE color chromaticity coordinates of the present glasses are found to lie in the prominent red region in the chromaticity diagram. The stimulated emission cross-section value of the MTB0.5Eu glass was found to be higher pertaining to the 5D0 → 7F2 transition compared to the other prepared glasses and reported literature thus suggests its suitability for red laser applications.

Surprising Rapid Collapse of Sirius B from Red Giant to White Dwarf Through Mass Transfer to Sirius a

NASA Astrophysics Data System (ADS)

Yousef, Shahinaz; Ali, Ola

2013-03-01

Sirius was observed in antiquity as a red star. In his famous astronomy textbook the Almagest written 140 AD, Ptolemy described the star Sirius as fiery red. He curiously depicted it as one of six red-colored stars. The other five are class M and K stars, such as Arcturus and Betelgeuse. Apparent confirmation in ancient Greek and Roman sources are found and Sirius was also reported red in Europe about 1400 years ago. Sirius must have changed to a white dwarf in the night of Ascension. The star chapter in the Quran started with "by the star as it collapsed (1) your companion have not gone astray nor being misled (2), and in verse 49 which is the rotation period of the companion Sirius B around Sirius A, it is said" He is the Lord of Sirius (49). If Sirius actually was red what could have caused it to change into the brilliant bluish-white star we see today? What the naked eye perceives as a single star is actually a binary star system, consisting of a white main sequence star of spectral type A1V, termed Sirius A, and a faint white dwarf companion of spectral type DA2, termed Sirius B. The red color indicates that the star seen then was a red giant. It looks that what they have seen in antiquity was Sirius B which was then a red giant and it collapsed to form a white dwarf. Since there is no evidence of a planetary nebula, then the red Sirius paradox can be solved in terms of stellar evolution with mass transfer. Sirius B was the most massive star which evolved to a red giant and filled the Roche lobe. Mass transfer to Sirius A occurred through the Lagrangian point. Sirius A then became more massive while Sirius B lost mass and shrank. Sirius B then collapsed abruptly into a white dwarf. In the case of Algol, Ptolmy observed it as white star but it was red at the time of El sufi. At present it is white. The rate of mass transfer from Sirius B to Sirius A, and from Algol B to A is estimated from observational data of colour change from red to bullish white to be 0

Genetic Evidence That the Red-Absorbing Form of Phytochrome B Modulates Gravitropism in Arabidopsis thaliana.

PubMed Central

Liscum, E.; Hangarter, R. P.

1993-01-01

Hypocotyls of dark-grown Arabidopsis seedlings exhibit strong negative gravitropism, whereas in red light, gravitropism is strongly reduced. Red/far-red light-pulse experiments and analysis of specific phytochrome-deficient mutants indicate that the red-absorbing (Pr) form of phytochrome B regulates normal hypocotyl gravitropism in darkness, and depletion of Pr by photoconversion to the far-red-absorbing form attenuates hypocotyl gravitropism. These studies provide genetic evidence that the Pr form of phytochrome has an active function in plant development. PMID:12231913

Stripped Red Giants - Helium Core White Dwarf Progenitors and their sdB Siblings

NASA Astrophysics Data System (ADS)

Heber, U.

2017-03-01

Some gaps in the mosaic of binary star evolution have recently been filled by the discoveries of helium-core white dwarf progenitors (often called extremely low mass (ELM) white dwarfs) as stripped cores of first-giant branch objects. Two varieties can be distinguished. One class is made up by SB1 binaries, companions being white dwarfs as well. Another class, the so-called EL CVn stars, are composite spectrum binaries, with A-Type companions. Pulsating stars are found among both classes. A riddle is posed by the apparently single objects. There is a one-to-one correspondence of the phenomena found for these new classes of star to those observed for sdB stars. In fact, standard evolutionary scenarios explain the origin of sdB stars as red giants that have been stripped close to the tip of first red giant branch. A subgroup of subluminous B stars can also be identified as stripped helium-cores of red giants. They form an extension of the ELM sequence to higher temperatures. Hence low mass white dwarfs of helium cores and sdB stars in binaries are close relatives in terms of stellar evolution.

A novel herpesvirus in 3 species of pheasants: mountain peacock pheasant (Polyplectron inopinatum), Malayan peacock pheasant (Polyplectron malacense), and Congo peafowl (Afropavo congensis).

PubMed

Seimon, T A; McAloose, D; Raphael, B; Honkavuori, K S; Chang, T; Hirschberg, D L; Lipkin, W I

2012-05-01

The mountain peacock pheasant (Polyplectron inopinatum), the Malayan peacock pheasant (Polyplectron malacense), and the Congo peafowl (Afropavo congensis) are all listed as vulnerable to extinction under the International Union for Conservation of Nature Red List of Threatened Species. Here the authors report fatal infection with a novel herpesvirus in all 3 species of birds. DNA was extracted from the livers of birds with hepatocellular necrosis and intranuclear eosinophilic inclusions consistent with herpesvirus infection. Based on degenerate herpesvirus primers and polymerase chain reaction, 220- and 519-base pair products of the herpes DNA polymerase and DNA terminase genes, respectively, were amplified. Sequence analysis revealed that all birds were likely infected with the same virus. At the nucleotide level, the pheasant herpesvirus had 92% identity with gallid herpesvirus 3 and 77.7% identity with gallid herpesvirus 2. At the amino acid level, the herpes virus had 93.8% identity with gallid herpesvirus 3 and 89.4% identity with gallid herpesvirus 2. These findings indicate that the closest relative to this novel herpesvirus is gallid herpesvirus 3, a nonpathogenic virus used widely in a vaccine against Marek's disease. In situ hybridization using probes specific to the peacock pheasant herpesvirus DNA polymerase revealed strong intranuclear staining in the necrotic liver lesions of an infected Malayan peacock pheasant but no staining in normal liver from an uninfected bird. The phasianid herpesvirus reported here is a novel member of the genus Mardivirus of the subfamily Alphaherpesvirinae and is distinct from other galliform herpesviruses.

Green synthesis of the Cu/Fe3O4 nanoparticles using Morinda morindoides leaf aqueous extract: A highly efficient magnetically separable catalyst for the reduction of organic dyes in aqueous medium at room temperature

NASA Astrophysics Data System (ADS)

Nasrollahzadeh, Mahmoud; Atarod, Monireh; Sajadi, S. Mohammad

2016-02-01

This paper reports the green and in-situ preparation of the Cu/Fe3O4 magnetic nanocatalyst synthesized using Morinda morindoides leaf extract without stabilizers or surfactants. The catalyst was characterized by XRD, SEM, EDS, UV-visible, TEM, VSM and TGA-DTA. The catalytic performance of the resulting nanocatalyst was examined for the reduction of 4-nitrophenol (4-NP), Congo red (CR) and Rhodamine B (RhB) in an environmental friendly medium at room temperature. The catalyst was recovered using an external magnet and reused several times without appreciable loss of its catalytic activity. In addition, the stability of the recycled catalyst has been proved by SEM and EDS techniques.

Synthesis and Optical Spectroscopy of YPO4:Eu3+ Orange-Red Phosphors

NASA Astrophysics Data System (ADS)

Yahiaoui, Z.; Hassairi, M. A.; Dammak, M.

2017-08-01

YPO4: x mol.% Eu3+ phosphors with different dopant concentrations ( x = 3, 5, 8, 11, 13) have been synthesized via high-temperature solid-state reaction. X-ray diffraction analysis and Raman and infrared (IR) spectroscopy were applied for detailed structural characterization. Under excitation at wavelength of 395 nm, the photoluminescence spectra displayed the 5D0 → 7F J ( J = 1, 2, 3, 4) intra-4 f shell transitions related to Eu3+ ion. The radiative lifetime was estimated using the Ω 2 and Ω 4 Judd-Ofelt intensity parameters. The highest luminescence intensity was achieved for an optimal europium concentration of 11 mol.%. The critical energy-transfer distance for Eu3+ ions was evaluated to be 10.74 Å. We also studied the temperature-dependent photoluminescence and Commission Internationale de l'Éclairage chromaticity diagram. It was found that Eu3+-doped YPO4 exhibited good thermal stability and its emission intensity decreased slightly above room temperature. In addition, the color purity of this phosphor was as high as 91% for the YPO4:13% Eu3+ sample, making it a potential orange-red phosphor for application in ultraviolet-pumped white light-emitting diodes.

The orphan germinant receptor protein GerXAO (but not GerX3b) is essential for L-alanine induced germination in Clostridium botulinum Group II.

PubMed

Brunt, Jason; Carter, Andrew T; Pye, Hannah V; Peck, Michael W

2018-05-04

Clostridium botulinum is an anaerobic spore forming bacterium that produces the potent botulinum neurotoxin that causes a severe and fatal neuro-paralytic disease of humans and animals (botulism). C. botulinum Group II is a psychrotrophic saccharolytic bacterium that forms spores of moderate heat resistance and is a particular hazard in minimally heated chilled foods. Spore germination is a fundamental process that allows the spore to transition to a vegetative cell and typically involves a germinant receptor (GR) that responds to environmental signals. Analysis of C. botulinum Group II genomes shows they contain a single GR cluster (gerX3b), and an additional single gerA subunit (gerXAO). Spores of C. botulinum Group II strain Eklund 17B germinated in response to the addition of L-alanine, but did not germinate following the addition of exogenous Ca 2+ -DPA. Insertional inactivation experiments in this strain unexpectedly revealed that the orphan GR GerXAO is essential for L-alanine stimulated germination. GerX3bA and GerX3bC affected the germination rate but were unable to induce germination in the absence of GerXAO. No role could be identified for GerX3bB. This is the first study to identify the functional germination receptor of C. botulinum Group II.

Intraplate compressional deformation in West-Congo and the Congo basin: related to ridge-puch from the South Atlantic spreading ridge?

NASA Astrophysics Data System (ADS)

Delvaux, Damien; Everaerts, Michel; Kongota Isasi, Elvis; Ganza Bamulezi, Gloire

2016-04-01

After the break-up and separation of South America from Africa and the initiation of the South-Atlantic mid-oceanic ridge in the Albian, at about 120 Ma, ridge-push forces started to build-up in the oceanic lithosphere and were transmitted to the adjacent continental plates. This is particularly well expressed in the passive margin and continental interior of Central Africa. According to the relations of Wiens and Stein (1985) between ridge-push forces and basal drag in function of the lithospheric age of oceanic plates, the deviatoric stress reaches a compressional maximum between 50 and 100, Ma after the initiation of the spreading ridge, so broadly corresponding to the Paleocene in this case (~70-20 Ma). Earthquake focal mechanism data show that the West-Congo margin and a large part of the Congo basin are still currently under compressional stresses with an horizontal compression parallel to the direction of the active transform fracture zones. We studied the fracture network along the Congo River in Kinshasa and Brazzaville which affect Cambrian sandstones and probably also the late Cretaceous-Paleocene sediments. Their brittle tectonic evolution is compatible with the buildup of ridge-push forces related to the South-Atlantic opening. Further inland, low-angle reverse faults are found affecting Jurassic to Middle Cretaceous cores from the Samba borehole in the Congo basin and strike-slip movements are recorded as a second brittle phase in the Permian cores of the Dekese well, at the southern margin of the Congo basin. An analysis of the topography and river network of the Congo basin show the development of low-amplitude (50-100 m) long wavelengths (100-300 km) undulations that can be interpreted as lithospheric buckling in response to the compressional intraplate stress field generated by the Mid-Atlantic ridge-push. Wiens, D.A., Stein, S., 1985. Implications of oceanic intraplate seismicity for plate stresses, driving forces and theology. Tectonophysics

Crystallization and preliminary X-ray diffraction analysis of red clover necrotic mosaic virus

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

Martin, Stanton L.; Guenther, Richard H.; Sit, Tim L.

2010-11-12

Red clover necrotic mosaic virus (RCNMV) is a species that belongs to the Tombusviridae family of plant viruses with a T = 3 icosahedral capsid. RCNMV virions were purified and were crystallized for X-ray analysis using the hanging-drop vapor-diffusion method. Self-rotation functions and systematic absences identified the space group as I23, with two virions in the unit cell. The crystals diffracted to better than 4 {angstrom} resolution but were very radiation-sensitive, causing rapid decay of the high-resolution reflections. The data were processed to 6 {angstrom} in the analysis presented here.

EVIDENCE FOR THE UNIVERSALITY OF PROPERTIES OF RED-SEQUENCE GALAXIES IN X-RAY- AND RED-SEQUENCE-SELECTED CLUSTERS AT z ∼ 1

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

Foltz, R.; Wilson, G.; DeGroot, A.

We study the slope, intercept, and scatter of the color–magnitude and color–mass relations for a sample of 10 infrared red-sequence-selected clusters at z ∼ 1. The quiescent galaxies in these clusters formed the bulk of their stars above z ≳ 3 with an age spread Δt ≳ 1 Gyr. We compare UVJ color–color and spectroscopic-based galaxy selection techniques, and find a 15% difference in the galaxy populations classified as quiescent by these methods. We compare the color–magnitude relations from our red-sequence selected sample with X-ray- and photometric-redshift-selected cluster samples of similar mass and redshift. Within uncertainties, we are unable tomore » detect any difference in the ages and star formation histories of quiescent cluster members in clusters selected by different methods, suggesting that the dominant quenching mechanism is insensitive to cluster baryon partitioning at z ∼ 1.« less

A Temporarily Red Light-Insensitive Mutant of Tomato Lacks a Light-Stable, B-Like Phytochrome.

PubMed Central

Van Tuinen, A.; Kerckhoffs, LHJ.; Nagatani, A.; Kendrick, R. E.; Koornneef, M.

1995-01-01

We have selected four recessive mutants in tomato (Lycopersicon esculentum Mill.) that, under continuous red light (R), have long hypocotyls and small cotyledons compared to wild type (WT), a phenotype typical of phytochrome B (phyB) mutants of other species. These mutants, which are allelic, are only insensitive to R during the first 2 days upon transition from darkness to R, and therefore we propose the gene symbol tri (temporarily red light insensitive). White light-grown mutant plants have a more elongated growth habit than that of the WT. An immunochemically and spectrophotometrically detectable phyB-like polypeptide detectable in the WT is absent or below detection limits in the tri1 mutant. In contrast to the absence of an elongation growth response to far-red light (FR) given at the end of the daily photoperiod (EODFR) in all phyB-deficient mutants so far characterized, the tri1 mutant responds to EODFR treatment. The tri1 mutant also shows a strong response to supplementary daytime far-red light. We propose that the phyB-like phytochrome deficient in the tri mutants plays a major role during de-etiolation and that other light-stable phytochromes can regulate the EODFR and shade-avoidance responses in tomato. PMID:12228517

What Controls the Hydrodynamics of the Central Congo River?

NASA Astrophysics Data System (ADS)

O'Loughlin, F.; Bates, P. D.

2014-12-01

Despite being the second largest river basin in the world, with a drainage area greater than 3.7 million square kilometres, little is known about the hydraulics of the Congo River. This lack of knowledge is mainly due to a mixture of conflicts and the difficulty of accessing existing data. We present results of studies which have focused primarily on the middle reach of the Congo River, located between Kisangani and Kinshasa, and its six main tributaries (Kasai, Ubangai, Sangha, Ruki, Lulonga and Lomami rivers). Through a combination of remotely sensed datasets and a hydrodynamic model we investigated what factors control the hydrodynamics of the middle reach. From the analysis of the remotely sensed datasets, we discover that variability in river width of the middle reach of the Congo is large and cannot be represented by empirical equations which relate channel geometry to basin area and discharge. Water surface slopes vary from 3.5 cm/km to 9 cm/km, which is far more than previous studies suggest. The remote datasets indicate that there exist 5 large constrictions in the river width which may result in backwater affecting between 11 and 33 percent of middle reach at low and high water respectively. These results were corroborated by the hydrodynamic model. In fact, when all constrictions caused by a narrowing in width of 1 km or more are considered, water levels along 43 percent of the middle reach change by at least 0.5 m. Using the hydrodynamic model we also investigated the importance of the wetlands to the attenuation of the flood wave through the system. Initial results suggest that for the Congo River, floodplains have far more impact on the peak magnitude than the timing of the flood wave. When the model was run with no floodplain interactions an increase in the magnitude of flood peak was observed, with the timing of the waves being consistent with observed measurements.

Sol-gel syntheses, luminescence, and energy transfer properties of α-GdB5O9:Ce(3+)/Tb(3+) phosphors.

PubMed

Sun, Xiaorui; Gao, Wenliang; Yang, Tao; Cong, Rihong

2015-02-07

Sol-gel method was applied to prepare homogenous and highly crystalline phosphors with the formulas α-GdB5O9:xTb(3+) (0 ≤ x ≤ 1), α-Gd1-xCexB5O9 (0 ≤ x ≤ 0.40), α-GdB5O9:xCe(3+), 0.30Tb(3+) (0 ≤ x ≤ 0.15) and α-GdB5O9:0.20Ce(3+), xTb(3+) (0 ≤ x ≤ 0.10). The success of the syntheses was proved by the linear shrinkage or expansion of the cell volumes against the substitution contents. In α-GdB5O9:xTb(3+), an efficient energy transfer from Gd(3+) to Tb(3+) was observed and there was no luminescence quenching. The exceptionally high efficiency of the f-f excitations of Tb(3+) implies that these phosphors may be good green-emitting UV-LED phosphors. For α-Gd1-xCexB5O9, Ce(3+) absorbs the majority of the energy and transfers it to Gd(3+). Therefore, the co-doping of Ce(3+) and Tb(3+) leads to a significant enhancement in the green emission of Tb(3+). Our current results together with the study on α-GdB5O9:xEu(3+) in the literature indicate that α-GdB5O9 is a good phosphor host with advantages including controllable preparation, diverse cationic doping, the absence of concentration quenching, and effective energy transfer.

New Phases of YBaCuGeO Superconductors Identified from X-ray Diffraction and Infra-red Absorption Measurements

NASA Astrophysics Data System (ADS)

Abo-Arais, Ahmed; Dawoud, Mohamad Ahmad Taher

2005-01-01

X-ray powder diffraction patterns and infra-red absorption spectra have been evaluated and analysed for the Y1 Ba2 Cu3 O7-d - Gex compound samples prepared by the solid state reaction with x values ranging from 0.0 to 1.13. All samples show bulk superconductivity above liquid nitrogen temperature using the levitation test (Meissner effect). Samples with Ge content up to x = 0.2 have offset Tc between 83K and 92K while the sample with x = 1.13 shows semiconducting behavior above 100K. As a result of the solid state interaction between YBCO and Ge, new phases are observed and determined, mainly three phases are concluded from X-ray powder diffraction analysis: (i) Ba2GeO4 (ii) Y2BaCuO5 (iii) BaCO3. The unit cell parameters a, b and c of the orthorhombic superconducting phase are calculated for all the prepared samples. The anisotropy factor is evaluated and related to the new structural phases in YBCO-Ge composite system. The I-R absorption spectra for the samples with orthorhombic symmetry have been determined. The phonon modes between ~ 400 cm-1 and 630 cm-1 are attributed to the Cu - O octahedron and pyramid vibrations for the CuO2 -planes and CuO-chains, while the peaks in the range from ~ 700 cm-1 to ~ 860 cm-1 may be due to defects such as the new phase Ba2GeO4 and the green phase Y2BaCuO5. The obtained results are discussed according to the superconductor - semi-conductor composite model and with the phonon-mediated charge transfer between CuO2 -planes and CuO- chains through apex oxygen (BaO).

Violence, selection and infant mortality in Congo.

PubMed

Dagnelie, Olivier; Luca, Giacomo Davide De; Maystadt, Jean-François

2018-05-01

This paper documents the effects of the recent civil war in the Democratic Republic of Congo on mortality both in utero and during the first year of life. It instruments for conflict intensity using a mineral price index, which exploits the exogenous variation in the potential value of mineral resources generated by changes in world mineral prices to predict the geographic distribution of the conflict. Using estimates of civil war exposure on mortality across male and female newborn to assess their relative health, it provides evidence of culling effect (in utero selection) as a consequence of in utero shocks. Copyright © 2018 Elsevier B.V. All rights reserved.

OBSERVATIONAL CONSTRAINTS ON RED AND BLUE HELIUM BURNING SEQUENCES

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

McQuinn, Kristen B. W.; Skillman, Evan D.; Dalcanton, Julianne J.

We derive the optical luminosity, colors, and ratios of the blue and red helium burning (HeB) stellar populations from archival Hubble Space Telescope observations of nineteen starburst dwarf galaxies and compare them with theoretical isochrones from Padova stellar evolution models across metallicities from Z = 0.001 to 0.009. We find that the observational data and the theoretical isochrones for both blue and red HeB populations overlap in optical luminosities and colors and the observed and predicted blue to red HeB ratios agree for stars older than 50 Myr over the time bins studied. These findings confirm the usefulness of applyingmore » isochrones to interpret observations of HeB populations. However, there are significant differences, especially for the red HeB population. Specifically, we find (1) offsets in color between the observations and theoretical isochrones of order 0.15 mag (0.5 mag) for the blue (red) HeB populations brighter than M{sub V} {approx} -4 mag, which cannot be solely due to differential extinction; (2) blue HeB stars fainter than M{sub V} {approx} -3 mag are bluer than predicted; (3) the slope of the red HeB sequence is shallower than predicted by a factor of {approx}3; and (4) the models overpredict the ratio of the most luminous blue to red HeB stars corresponding to ages {approx}< 50 Myr. Additionally, we find that for the more metal-rich galaxies in our sample (Z {approx}> 0.5 Z{sub sun}), the red HeB stars overlap with the red giant branch stars in the color-magnitude diagrams, thus reducing their usefulness as indicators of star formation for ages {approx}> 100 Myr.« less

Blue-shifted and red-shifted hydrogen bonds: Theoretical study of the CH3CHO· · ·HNO complexes

NASA Astrophysics Data System (ADS)

Yang, Yong; Zhang, Weijun; Gao, Xiaoming

The blue-shifted and red-shifted H-bonds have been studied in complexes CH3CHO?HNO. At the MP2/6-31G(d), MP2/6-31+G(d,p) MP2/6-311++G(d,p), B3LYP/6-31G(d), B3LYP/6-31+G(d,p) and B3LYP/6-311++G(d,p) levels, the geometric structures and vibrational frequencies of complexes CH3CHO?HNO are calculated by both standard and CP-corrected methods, respectively. Complex A exhibits simultaneously red-shifted C bond H?O and blue-shifted N bond H?O H-bonds. Complex B possesses simultaneously two blue-shifted H-bonds: C bond H?O and N bond H?O. From NBO analysis, it becomes evident that the red-shifted C bond H?O H-bond can be explained on the basis of the two opposite effects: hyperconjugation and rehybridization. The blue-shifted C bond H?O H-bond is a result of conjunct C bond H bond strengthening effects of the hyperconjugation and the rehybridization due to existence of the significant electron density redistribution effect. For the blue-shifted N bond H?O H-bonds, the hyperconjugation is inhibited due to existence of the electron density redistribution effect. The large blue shift of the N bond H stretching frequency is observed because the rehybridization dominates the hyperconjugation.

Head Lice of Pygmies Reveal the Presence of Relapsing Fever Borreliae in the Republic of Congo

PubMed Central

Amanzougaghene, Nadia; Akiana, Jean; Mongo Ndombe, Géor; Davoust, Bernard; Nsana, Nardiouf Sjelin; Parra, Henri-Joseph; Fenollar, Florence; Raoult, Didier; Mediannikov, Oleg

2016-01-01

Background Head lice, Pediculus humanus capitis, occur in four divergent mitochondrial clades (A, B, C and D), each having particular geographical distributions. Recent studies suggest that head lice, as is the case of body lice, can act as a vector for louse-borne diseases. Therefore, understanding the genetic diversity of lice worldwide is of critical importance to our understanding of the risk of louse-borne diseases. Methodology/Principal Findings Here, we report the results of the first molecular screening of pygmies’ head lice in the Republic of Congo for seven pathogens and an analysis of lice mitochondrial clades. We developed two duplex clade-specific real-time PCRs and identified three major mitochondrial clades: A, C, and D indicating high diversity among the head lice studied. We identified the presence of a dangerous human pathogen, Borrelia recurrentis, the causative agent of relapsing fever, in ten clade A head lice, which was not reported in the Republic of Congo, and B. theileri in one head louse. The results also show widespread infection among head lice with several species of Acinetobacter. A. junii was the most prevalent, followed by A. ursingii, A. baumannii, A. johnsonii, A. schindleri, A. lwoffii, A. nosocomialis and A. towneri. Conclusions/Significance Our study is the first to show the presence of B. recurrentis in African pygmies’ head lice in the Republic of Congo. This study is also the first to report the presence of DNAs of B. theileri and several species of Acinetobacter in human head lice. Further studies are needed to determine whether the head lice can transmit these pathogenic bacteria from person to another. PMID:27911894

Instense red phosphors for UV light emitting diode devices.

PubMed

Cao, Fa-Bin; Tian, Yan-Wen; Chen, Yong-Jie; Xiao, Lin-Jiu; Liu, Yun-Yi

2010-03-01

Ca(x)Sr1-x-1.5y-0.5zMoO4:yEu3+ zNa+ red phosphors were prepared by solid-state reaction using Na+ as charge supply for LEDs (light emitting diodes). The content of charge compensator, Ca2+ concentration, synthesis temperature, reaction time, and Eu3+ concentration were the keys to improving the properties of luminescence and crystal structure of red phosphors. The photoluminescence spectra shows the red phosphors are effectively excited at 616 nm by 311 nm, 395 nm, and 465 nm light. The wavelengths of 395 and 465 nm nicely match the widely applied emission wavelengths of ultraviolet or blue LED chips. Its chromaticity coordinates (CIE) are calculated to be x = 0.65, y = 0.32. Bright red light can be observed by the naked eye from the LED-based Ca0.60Sr0.25MoO4:0.08Eu3+ 0.06Na+.

Outbreak of cholera in the Republic of Congo and the Democratic Republic of Congo, and cholera worldwide.

PubMed

Kelvin, Alyson Ann

2011-10-13

Cholera is an acute intestinal disease caused by infection of the Vibrio cholerae bacterium.  Often manifested as a constant diarrhoeal disease, Cholera is associated with significant mortality as well as economic loss due to the strain on health care.  Cholera often affects nations with lower economic status.  The recent outbreak of cholera in the Republic of Congo and the Democratic Republic of Congo has affected thousands of people.  Here we review the past cholera epidemiology, molecular mechanisms of the bacterium, and the political and environmental aspects that affect the treatment and eradication of this disease.

Crystal structure and europium luminescence of NaMgH3-xFx

NASA Astrophysics Data System (ADS)

Pflug, Christian; Franz, Alexandra; Kohlmann, Holger

2018-02-01

The solid solution series NaMgH3-xFx (x = 0, 0.5, 1, 1.5, 2, 2.5, 3) was synthesized by solid-state reactions under hydrogen gas pressure from binary ionic hydrides, fluorides and magnesium. Rietveld refinement based on X-ray powder diffraction data revealed the GdFeO3-structure type for all compounds and a trend of lattice parameters according to Vegard's law. The anion distribution in NaMgD2F and NaMgD1.5F1.5 was found to be statistical by Rietveld refinement based on neutron powder diffraction data. Photoluminescence measurements on europium(II) substituted NaMgH3-xFx revealed a strong red shift of the emission wavelength (λem = 665 nm for NaMgH2F:Eu) in comparison to violet emitting NaMgF3:Eu.

Luminescence and scintillation characteristics of (GdxY3-x)Al2Ga3O12:Ce (x = 1,2,3) single crystals

NASA Astrophysics Data System (ADS)

Chewpraditkul, Warut; Pattanaboonmee, Nakarin; Sakthong, Ongsa; Chewpraditkul, Weerapong; Szczesniak, Tomasz; Moszynski, Marek; Kamada, Kei; Yoshikawa, Akira; Nikl, Martin

2018-02-01

The luminescence and scintillation characteristics of Czochralski-grown (GdxY3-x)Al2Ga3O12:Ce (x = 1,2,3) single crystals are presented. With increasing Gd content in this garnet host, the 5d2 absorption band was blue-shifted while the 5d1 absorption and 5d1 → 4f emission bands were red-shifted due to an increase in the crystal field splitting of the 5d levels. In addition, the luminescence quenching temperature of the Ce3+emission and activation energy for thermal quenching decreased with increasing Gd content. The Gd3+ → Ce3+ energy transfer was evidenced by photoluminescence excitation spectra of Ce3+ emission. At 662 keV γ - rays, the light yield (LY) of 48,600 ph/MeV and energy resolution of 6.5% was measured for a Gd3Al2Ga3O12:Ce crystal. Scintillation decay measurements were performed using the time-correlated single photon counting technique. Superior time resolution of Gd3Al2Ga3O12:Ce is due to its high LY and fast scintillation response. The total mass attenuation coefficients at 60 and 662 keV γ - rays were also determined.

Crystal Chemistry and Magnetism of Ternary Actinoid Boron Carbides UB 1- xC 1+ x and U 1- xMxB 2C with M = Sc, Lu, and Th

NASA Astrophysics Data System (ADS)

Rogl, P.; Rupp, B.; Felner, I.; Fischer, P.

1993-06-01

Within the homogeneous range of uranium monocarbide UB 1- xC 1+ x, the crystal structures of stoichiometric UBC and of the carbon-rich solid solution UB 0.78C 1.22, have been refined from single-crystal X-ray counter data. From X-ray analysis crystal symmetry in both cases is consistent with the centro-symmetric space group Cmcm and there are no indications of superstructure formation. In contrast to the fully ordered atom arrangement revealed for stoichiometric UBC ( a = 0.35899(4), b = 1.19781(12), c = 0.33474(3) nm), random occupation by boron and carbon atoms is observed for the boron site in UB 0.78C 1.22 ( a = 0.35752(4), b = 1.18584(3), c = 0.33881(4) nm). For 279(278) reflections (|F 0| > 3σ) the obtained reliability factors R x = ∑|ΔF|/∑| F0| were R x = 0.069 for UBC and R x = 0.050 for UB 0.78C 1.22. Neutron powder diffraction experiments at 9 and 295 K unambiguously revealed full occupancy by the nonmetal atoms in UB 0.78C 1.22 and prove the statistical occupation of B and C atoms in the B-sites. For the orthorhombic symmetry Cmcm, refinement was not better than R1 = 0.044. A model calculation in monoclinic symmetry C12/ m1, however, resulted in a significant reduction of the residual value to R1 = 0.030, releasing spatial constraints on the boron atoms. Thus the boron-boron chain in Cmcm (B-B = 0.1874 nm) is dissolved into boron pairs (B-B = 0.1706 nm) which are loosely bound at a distance of 0.2043 nm. The formation of C-B-B-C groups corresponds to the structure types of ThBC and Th 3B 2C 3. The magnetic behavior has been investigated in the temperature range from 4.2 K to 1000 K for UB 1- xC 1+ x (UBC-type) and U 1- xMxB 2C (ThB 2C-type for the high temperature modification and 1-UB 2C-type for the low temperature modification) with U partially substituted by Th or Sc, Lu. From magnetic susceptibilities, the alloys UB 1- xC 1+ x reveal temperature independent paramagnetism with typical intermediate valence fluctuation behavior ( TSF ˜ 350 K

Understanding the role of A-site and B-site cations on piezoelectric instability in lead--free (1-x) BaTiO3 -- xA(Cu1/3Nb2/3)O3 (A = Sr, Ca, Ba) solid solutions

NASA Astrophysics Data System (ADS)

Maurya, Deepam; Zhou, Yuan; Priya, Shashank

2013-03-01

This study provides fundamental understanding of the enhanced piezoelectric instability in lead-free piezoelectric (1-x) BaTiO3-xA(Cu1/3Nb2/3) O3(A: Sr, Ba and Ca and x = 0.0-0.03) solid solutions. These compositions were found to exhibit large longitudinal piezoelectric constant (d33) of ~330 pC/N and electromechanical planar coupling constant (kp) ~ 46% at room temperature. The X-ray diffraction coupled with atomic pair distribution functions (PDF)s indicated increase in local polarization. Raman scattering and electron paramagnetic resonance (EPR) analysis revealed that substitutions on A and B-site both substantially perturbed the local octahedral dynamics and resulted in localized nano polar regions with lower symmetry. The presence of nano domains and local structural distortions smears the Curie peak resulting in diffuse order-disorder type phase transitions. The effect of these distortions on the variations in physical property was modeled and analyzed within the context of nanodomains and phase transitions. *spriya@vt.edu The financial support from National Science Foundation and Office of Basic Energy Science, Department of Energy (Microscopy analysis) is gratefully acknowledged. The authors would also like to acknowledge the support from KIMS (new piezoelectric)

Synthesis and morphology of Ba1-xRE2x/3Nb2O6 nanocrystals with tungsten bronze structure in RE2O3-BaO-Nb2O5-B2O3 glasses (RE: Sm, Eu, Gd, Dy, Er)

NASA Astrophysics Data System (ADS)

Ida, H.; Shinozaki, K.; Honma, T.; Oh-ishi, K.; Komatsu, T.

2012-12-01

Ba1-xRE2x/3Nb2O6 nanocrystals with a tetragonal tungsten bronze (TTB) structure are synthesized using a conventional glass crystallization technique in 2.3RE2O3-27.4BaO-34.3Nb2O5-36B2O3 (mol%) (RE=Sm, Eu, Gd, Dy, and Er) glasses. One sharp crystallization peak is observed at ∼670 °C in both powdered and bulk glasses, and the formation of Ba1-xRE2x/3Nb2O6 nanocrystals with unit cell parameters of a∼1.24 nm and c∼0.39 nm was confirmed. It is found from high resolution transmission electron microscope observations that the morphology of Ba1-xRE2x/3Nb2O6 nanocrystals is ellipsoidal. Their average particle size is in the range of 15-60 nm and decreases with decreasing ionic radius of RE3+ being present in the precursor glasses. The optical transparent crystallized glass (bulk) shows the total photoluminescence (PL) quantum yield of 53% in the visible region of Eu3+ ions, suggesting a high potential of Ba1-xRE2x/3Nb2O6 nanocrystals as PL materials.

Tetrapeptide-coumarin conjugate 3D networks based on hydrogen-bonded charge transfer complexes: gel formation and dye release.

PubMed

Guo, Zongxia; Gong, Ruiying; Jiang, Yi; Wan, Xiaobo

2015-08-14

Oligopeptide-based derivatives are important synthons for bio-based functional materials. In this article, a Gly-(L-Val)-Gly-(L-Val)-coumarin (GVGV-Cou) conjugate was synthesized, which forms 3D networks in ethanol. The gel nanostructures were characterized by UV-vis spectroscopy, FT-IR spectroscopy, X-ray diffraction (XRD), SEM and TEM. It is suggested that the formation of charge transfer (CT) complexes between the coumarin moieties is the main driving force for the gel formation. The capability of the gel to encapsulate and release dyes was explored. Both Congo Red (CR) and Methylene Blue (MB) can be trapped in the CT gel matrix and released over time. The present gel might be used as a functional soft material for guest encapsulation and release.

Passive optical remote sensing of Congo River bathymetry using Landsat

NASA Astrophysics Data System (ADS)

Ache Rocha Lopes, V.; Trigg, M. A.; O'Loughlin, F.; Laraque, A.

2014-12-01

While there have been notable advances in deriving river characteristics such as width, using satellite remote sensing datasets, deriving river bathymetry remains a significant challenge. Bathymetry is fundamental to hydrodynamic modelling of river systems and being able to estimate this parameter remotely would be of great benefit, especially when attempting to model hard to access areas where the collection of field data is difficult. One such region is the Congo Basin, where due to past political instability and large scale there are few studies that characterise river bathymetry. In this study we test whether it is possible to use passive optical remote sensing to estimate the depth of the Congo River using Landsat 8 imagery in the region around Malebo Pool, located just upstream of the Kinshasa gauging station. Methods of estimating bathymetry using remotely sensed datasets have been used extensively for coastal regions and now more recently have been demonstrated as feasible for optically shallow rivers. Previous river bathymetry studies have focused on shallow rivers and have generally used aerial imagery with a finer spatial resolution than Landsat. While the Congo River has relatively low suspended sediment concentration values the application of passive bathymetry estimation to a river of this scale has not been attempted before. Three different analysis methods are tested in this study: 1) a single band algorithm; 2) a log ratio method; and 3) a linear transform method. All three methods require depth data for calibration and in this study area bathymetry measurements are available for three cross-sections resulting in approximately 300 in-situ measurements of depth, which are used in the calibration and validation. The performance of each method is assessed, allowing the feasibility of passive depth measurement in the Congo River to be determined. Considering the scarcity of in-situ bathymetry measurements on the Congo River, even an approximate

Study on photocatalytic activity of nanosized Co0.3Zn0.7Fe2O4 synthesized by hydrothermal method

NASA Astrophysics Data System (ADS)

Mondal, R.; Sarkar, K.; Dey, S.; Bhattacharjee, S.; Ghosh, C. K.; Kumar, S.

2018-04-01

We have reported the photocatalytic activity of nanosized Co0.3Zn0.7Fe2O4 (CZM) synthesized by hydrothermal method. Powder x-ray diffraction (PXRD), field emission and transmission electron microscopic techniques have been employed for structural and microstructural characterization of the sample. The Rietveld refinement of the PXRD pattern of CZM reveals that the sample is a single phase spinel ferrite of F d 3 ¯m symmetry having crystallite size ˜ 20 nm. The average particle size is ˜ 23 nm. The photocatalytic study suggests that CZM can be suitably used as an efficient (rate constant and % degradation are 7.4×10-2 min-1, 95.76 % at 40 min, respectively), magnetically separable, recyclable photocatalyst for removal of Congo Red from its aqueous solution.

Brightly Luminescent and Color-Tunable Colloidal CH3NH3PbX3 (X = Br, I, Cl) Quantum Dots: Potential Alternatives for Display Technology.

PubMed

Zhang, Feng; Zhong, Haizheng; Chen, Cheng; Wu, Xian-gang; Hu, Xiangmin; Huang, Hailong; Han, Junbo; Zou, Bingsuo; Dong, Yuping

2015-04-28

Organometal halide perovskites are inexpensive materials with desirable characteristics of color-tunable and narrow-band emissions for lighting and display technology, but they suffer from low photoluminescence quantum yields at low excitation fluencies. Here we developed a ligand-assisted reprecipitation strategy to fabricate brightly luminescent and color-tunable colloidal CH3NH3PbX3 (X = Br, I, Cl) quantum dots with absolute quantum yield up to 70% at room temperature and low excitation fluencies. To illustrate the photoluminescence enhancements in these quantum dots, we conducted comprehensive composition and surface characterizations and determined the time- and temperature-dependent photoluminescence spectra. Comparisons between small-sized CH3NH3PbBr3 quantum dots (average diameter 3.3 nm) and corresponding micrometer-sized bulk particles (2-8 μm) suggest that the intense increased photoluminescence quantum yield originates from the increase of exciton binding energy due to size reduction as well as proper chemical passivations of the Br-rich surface. We further demonstrated wide-color gamut white-light-emitting diodes using green emissive CH3NH3PbBr3 quantum dots and red emissive K2SiF6:Mn(4+) as color converters, providing enhanced color quality for display technology. Moreover, colloidal CH3NH3PbX3 quantum dots are expected to exhibit interesting nanoscale excitonic properties and also have other potential applications in lasers, electroluminescence devices, and optical sensors.

X-15 Mated to B-52 Captive Flight

NASA Technical Reports Server (NTRS)

1959-01-01

. Between 1966 and 1975, the B-52 served as the launch aircraft for 127 of the 144 wingless lifting body flights. In the 1970s and 1980s, the B-52 was the launch aircraft for several aircraft at what is now the Dryden Flight Research Center, Edwards, California, to study spin-stall, high-angle-of attack, and maneuvering characteristics. These included the 3/8-scale F-15/spin research vehicle (SRV), the HiMAT (Highly Maneuverable Aircraft Technology) research vehicle, and the DAST (drones for aerodynamic and structural testing). The aircraft supported the development of parachute recovery systems used to recover the space shuttle solid rocket booster casings. It also supported eight orbiter (space shuttle) drag chute tests in 1990. In addition, the B-52 served as the air launch platform for the first six Pegasus space boosters. During its many years of service, the B-52 has undergone several modifications. The first major modification was made by North American Aviation (now part of Boeing) in support of the X-15 program. This involved creating a launch-panel-operator station for monitoring the status of the test vehicle being carried, cutting a large notch in the right inboard wing flap to accommodate the vertical tail of the X-15 aircraft, and installing a wing pylon that enables the B-52 to carry research vehicles and test articles to be air-launched/dropped. Located on the right wing, between the inboard engine pylon and the fuselage, this wing pylon was subjected to extensive testing prior to its use. For each test vehicle the B-52 carried, minor changes were made to the launch-panel operator's station. Built originally by the Boeing Company, the NASA B-52 is powered by eight Pratt & Whitney J57-19 turbojet engines, each of which produce 12,000 pounds of thrust. The aircraft's normal launch speed has been Mach 0.8 (about 530 miles per hour) and its normal drop altitude has been 40,000 to 45,000 feet.. It is 156 feet long and has a wing span of 185 feet. The heaviest