HPLC separation post-column reaction, UV-visible and fluorescence detection of trace UO/sub 2//sup 2 +//U/sup 4 +/ species in aqueous solutions

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

Karimi, A.R.

In this study a method for the measurement of uranium in natural waters at sub-ppB concentration levels by the separation and determination of U/sup 4 +/ and UO/sub 2//sup 2 +/ species is proposed. Reversed phase high performance liquid chromatography, followed by a post-column reaction and a sensitive UV-visible detection system was the method of choice to determine qualitatively and quantitatively the two uranium species. Also a cation-exchange and fluorescence detection system was studied for separation and determination of UO/sub 2//sup 2 +/ ions. Uranyl ion was selectively complexed with L-phenylalanine moetie in the sample solution containing U/sup 4 +/more » ions. Uranium (IV)/U(VI)-ligand was separated on a C/sub 18/ column with acetate buffer. Hexanesulfonate was found to be the choice for ion-pair reagent. The separation was best done with the acetate buffer at .01 M concentration and pH of 3.5. Absorption of the two species were measured after a post-column reaction with Arsenazo-III. Chromatographic parameters were calculated and a calibration curves were constructed. The detection limit for the procedure was 0.7 ..mu..g/mo and 1.2..mu..g/ml for U(IV) and U(VI) respectively. When U(VI) was separated on the cation-exchange column the limit of detection was calculated to be 1 ..mu..g/ml. The direct fluorometric method for U(VI) measurement results in a detection limit of 2 ppB and upper concentration limit of 2 ppM. The effect of interfering ions in the direct method of determination could be eliminated by dilution of sample solution.« less

Fluoride and calcium concentrations in the biofilm fluid after use of fluoridated dentifrices supplemented with polyphosphate salts.

PubMed

Nagata, Mariana Emi; Delbem, Alberto Carlos Botazzo; Hall, Kevin Bruce; Buzalaf, Marília Afonso Rabelo; Pessan, Juliano Pelim

2017-04-01

The present study evaluated fluoride (F) and calcium (Ca) concentrations in the biofilm fluid formed in situ under cariogenic challenge after using F dentifrices supplemented or not with sodium trimetaphosphate (TMP) or calcium glycerophosphate (CaGP). Volunteers (n = 12) were randomly divided into 5 groups according to the toothpastes used: placebo (without F, CaGP or TMP), 1100 ppm F (1100F) and low-fluoride dentifrice (LFD, 550 ppm F) with no supplementation (550F) or supplemented with 1 % TMP (550F-TMP) or 0.25 % CaGP (550F-CaGP). In each phase, volunteers wore palatal appliances containing 4 bovine enamel blocks. Cariogenic challenge was performed with 30 % sucrose solution, 6 times/day. On the morning of the eigth day, biofilm samples were collected 12 h and 1 h after brushing and cariogenic challenge. F and Ca analyses in the biofilm fluid were performed with the inverted electrode after buffering with TISAB III and using the Arsenazo III method, respectively. Data were submitted to two-way ANOVA (repeated measures) and Student-Newman-Keuls test (p < 0.05). A dose-response relationship was verified between F concentrations in the dentifrices and in the biofilm fluid. Significant differences were observed among placebo, 550F, and 1100F only 1 h after brushing, without statistical differences among 550F, 550F-TMP, and 550F-CaGP. No defined trend was observed among the groups regarding Ca concentrations, with the highest values seen for placebo and 550F-CaGP. The anticaries effect of LFDs supplemented with CaGP or TMP cannot be related to an increased availability of F and Ca in the biofilm fluid. The better performance of LFDs containing CaGP or TMP shown in previous studies should be attributed to their ability to interact with tooth enamel and with the biofilm, rather to their effect on the biofilm fluid.

New reversed phase-high performance liquid chromatographic method for selective separation of yttrium from all rare earth elements employing nitrilotriacetate complexes in anion exchange mode.

PubMed

Dybczyński, Rajmund S; Kulisa, Krzysztof; Pyszynska, Marta; Bojanowska-Czajka, Anna

2015-03-20

Separation of Y from other rare earth elements (REE) is difficult because of similarity of its ionic radius to ionic radii of Tb, Dy and Ho. In the new RP-HPLC system with C18 column, tetra-n-butyl ammonium hydroxide (TBAOH) as an ion interaction reagent (IIR), nitrilotriacetic acid (NTA) as a complexing agent at pH=2.8-3.5, and post column derivatization with Arsenazo III, yttrium is eluted in the region of light REE, between Nd and Sm and is base line separated from Nd and Sm and even from promethium. Simple model employing literature data on complex formation of REE with NTA and based on anion exchange mechanism was developed to foresee the order of elution of individual REE. The model correctly predicted that lanthanides up to Tb will be eluted in the order of increasing Atomic Number (At.No.) but all heavier REE will show smaller retention factors than Tb. Concurrent UV/VIS detection at 658nm and the use of radioactive tracers together with γ-ray spectrometric measurements made possible to establish an unique elution order of elution of REE: La, Ce, Pr, Nd, Pm, Y, Sm, Er, Ho, Tm, Yb, Eu, Lu, Dy+Gd, Tb, Sc. The real place of Y however, in this elution series differs from that predicted by the model (Y between Sm and Eu). The method described in this work enables selective separation of Y from La, Ce, Pr, Nd, Pm, Sm and all heavier REE treated as a group. Copyright © 2015 Elsevier B.V. All rights reserved.

IMPROVEMENT OF THE EXTRACTION SEPARATION OF URANIUM AND ZIRCONIUM USING ZIRCONIUM-MASKING REAGENTS (in German)

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

Kyrs, M.; Caletka, R.; Selucky, P.

1963-12-01

The masking capacities of a series of reagents were studied in the zirconium extraction with tributyl phosphate solution in the presence of nitric acid. It was established that with many reagents an improvement of the separation of uranium from zirconium could be obtained. The efficiency of the reagents increases in the series tannin, oxalic acid, tiron, pyrogallol, and Arsenazo I. (tr-auth)

Impact of laminar flow velocity of different acids on enamel calcium loss.

PubMed

Attin, T; Becker, K; Wiegand, A; Tauböck, T T; Wegehaupt, F J

2013-03-01

The aim of the study was to evaluate the impact of flow velocity under laminar flow conditions of different acidic solutions on enamel erosion. A total of 240 bovine enamel specimens were prepared and allocated to 30 groups (n = 8 each). Samples of 18 groups were superfused in a flow chamber system with laminar flow behavior using 1 ml of citric acid or hydrochloric acid (HCl) of pH 2.0, 2.6 or 3.0. Flow rates in the sample chamber were adjusted to 10, 60 or 100 μl/min. To simulate turbulent flow behavior, samples of six groups were immersed in 1 ml of the respective solution, which was vortexed (15 min, 600 rpm). For simulating non-agitated conditions, specimens of the remaining six groups were immersed in 1 ml of the respective solution without stirring. Calcium in the solutions, released from the enamel samples, was determined using Arsenazo III method. For acidic solutions of pH 2.6 and 3.0, erosive potential of citric acid was equivalent to that of HCl at a flow of 100 μl/min. The same observation was made for the samples subjected to turbulent conditions at pH 3. At all other conditions, citric acid induced a significantly higher calcium loss than HCl. It is concluded that under slow laminar flow conditions, flow rate variations lead to higher erosive impact of citric acid compared to hydrochloric acid at pH 2.0, but not at pH ≥ 2.6 and increasing laminar flow or turbulent conditions. Erosive enamel dissolution under laminar flow conditions is a complex issue influenced by flow rate and acidic substrate.

Ionized calcium concentrations in squid axons

PubMed Central

1976-01-01

Values for ionized [Ca] in squid axons were obtained by measuring the light emission from a 0.1-mul drop of aequorin confined to a plastic dialysis tube of 140-mum diameter located axially. Ionized Ca had a mean value of 20 x 10(-9) M as judged by the subsequent introduction of CaEGTA/EGTA buffer (ratio ca. 0.1) into the axoplasm, and light measurement on a second aequorin drop. Ionized Ca in axoplasma was also measured by introducing arsenazo dye into an axon by injection and measuring the Ca complex of such a dye by multichannel spectrophotometry. Values so obtained were ca. 50 x 10(-9) M as calibrated against CaEGTA/EGTA buffer mixtures. Wth a freshly isolated axon in 10 mM Ca seawater, the aequorin glow invariably increased with time; a seawater [Ca] of 2-3 mM allowed a steady state with respect to [Ca]. Replacement of Na+ in seawater with choline led to a large increase in light emission from aequorin. Li seawater partially reversed this change and the reintroduction of Na+ brought light levels back to their initial value. Stimulation at 60/s for 2-5 min produced an increase in aequorin glow about 0.1% of that represented by the known Ca influx, suggesting operationally the presence of substantial Ca buffering. Treatment of an axon with CN produced a very large increase in aequorin glow and in Ca arsenazo formation only if the external seawater contained Ca. PMID:818340

Ca sup 2+ binding capacity of cytoplasmic proteins from rod photoreceptors is mainly due to arrestin

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

Huppertz, B.; Weyand, I.; Bauer, P.J.

1990-06-05

Arrestin (also called S-antigen or 48-kDa protein) binds to photoexcited and phosphorylated rhodopsin and, thereby, blocks competitively the activation of transducin. Using Ca{sup 2+} titration in the presence of the indicator arsenazo III and {sup 45}Ca{sup 2+} autoradiography, we show that arrestin is a Ca2(+)-binding protein. The Ca{sup 2+} binding capacity of arresting-containing protein extracts from bovine rod outer segments is about twice as high as that of arrestin-depleted extracts. The difference in the Ca{sup 2+} binding of arrestin-containing and arrestin-depleted protein extracts was attributed to arrestin. Both, these difference-measurements of protein extracts and the measurements of purified arrestin yieldmore » dissociation constants for the Ca{sup 2+} binding of arrestin between 2 and 4 microM. The titration curves are consistent with a molar ratio of one Ca{sup 2+} binding site per arrestin. No Ca{sup 2+} binding in the micromolar range was found in extracts containing mainly transducin and cGMP-phosphodiesterase. Since arrestin is one of the most abundant proteins in rod photoreceptors occurring presumably up to millimolar concentrations in rod outer segments, we suggest that aside from its function to prevent the activation of transducin, arrestin acts probably as an intracellular Ca{sup 2+} buffer.« less

Intracellular calcium buffering capacity in isolated squid axons

PubMed Central

Brinley, FJ; Tiffert, T; Scarpa, A; Mullins, LJ

1977-01-01

Changes in ionized calcium were studied in axons isolated from living squid by measuring absorbance of the Ca binding dye Arsenazo III using multiwavelength differential absorption spectroscopy. Absorption changes measured in situ were calibrated in vitro with media of ionic composition similar to axoplasm containing CaEGTA buffers. Calcium loads of 50-2,500 μmol/kg axoplasm were induced by microinjection, by stimulation in 112 mM Ca seawater, or by soaking in choline saline with 1-10 mM Ca. Over this range of calcium loading of intact axoplasm, the ionized calcium in the axoplasm rose about 0.6 nM/μM load. Similar loading in axons preteated with carbonyl cyanide 4- trifluoromethoxyphenylhydrazone (FCCP) to inhibit the mitochondrial proton gradient increased ionized calcium by 5-7 percent of the imposed load, i.e. 93-95 percent of the calcium load was buffered by a process insensitive to FCCP. This FCCP- insensitive buffer system was not saturated by the largest calcium loads imposed, indicating a capacity of at least several millimolar. Treatment of previously loaded axons with FCCP or apyrase plus cyanide produced rises in ionized calcium which could be correlated with the extent of the load. Analysis of results indicated that, whereas only 6 percent of the endogenous calcium in fresh axons is stored in the FCCP-sensitive (presumably mitochondrial) buffer system, about 30 percent of an imposed exogenous load in the range of 50-2,500 μM is taken up by this system. PMID:894260

Effect of safflower oil on the protective properties of the in situ formed salivary pellicle.

PubMed

Hannig, C; Wagenschwanz, C; Pötschke, S; Kümmerer, K; Kensche, A; Hoth-Hannig, W; Hannig, M

2012-01-01

The prevalence of dental erosion is still increasing. A possible preventive approach might be rinsing with edible oils to improve the protective properties of the pellicle layer. This was tested in the present in situ study using safflower oil. Pellicle formation was carried out in situ on bovine enamel slabs fixed buccally to individual upper jaw splints (6 subjects). After 1 min of pellicle formation subjects rinsed with safflower oil for 10 min, subsequently the samples were exposed in the oral cavity for another 19 min. Enamel slabs without oral exposure and slabs exposed to the oral cavity for 30 min without any rinse served as controls. After pellicle formation in situ, slabs were incubated in HCl (pH 2; 2.3; 3) for 120 s, and kinetics of calcium and phosphate release were measured photometrically (arsenazo III, malachite green). Furthermore, the ultrastructure of the pellicles was evaluated by transmission electron microscopy (TEM). Pellicle alone reduced erosive calcium and phosphate release significantly at all pH values. Pellicle modification by safflower oil resulted in an enhanced calcium loss at all pH values and caused an enhanced phosphate loss at pH 2.3. TEM indicated scattered accumulation of lipid micelles and irregular vesicle-like structures attached to the oil-treated pellicle layer. Acid etching affected the ultrastructure of the pellicle irrespective of oil rinsing. The protective properties of the pellicle layer against extensive erosive attacks are limited and mainly determined by pH. The protective effects are modified and reduced by rinses with safflower oil. Copyright © 2012 S. Karger AG, Basel.

The kinetics of lanthanide complexation by EDTA and DTPA in lactate media.

PubMed

Nash, K L; Brigham, D; Shehee, T C; Martin, A

2012-12-28

The interaction of trivalent lanthanide and actinide cations with polyaminopolycarboxylic acid complexing agents in lactic acid buffer systems is an important feature of the chemistry of the TALSPEAK process for the separation of trivalent actinides from lanthanides. To improve understanding of metal ion coordination chemistry in this process, the results of an investigation of the kinetics of lanthanide complexation by ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA) and diethylenetriamine-N,N,N',N'',N''-pentaacetic acid (DTPA) in 0.3 M lactic acid/0.3 M ionic strength solution are reported. Progress of the reaction was monitored using the distinctive visible spectral changes attendant to lanthanide complexation by the colorimetric indicator ligand Arsenazo III, which enables the experiment but plays no mechanistic role. Under the conditions of these experiments, the reactions occur in a time regime suitable for study by stopped-flow spectrophotometric techniques. Experiments have been conducted as a function of EDTA/DTPA ligand concentration, total lactic acid concentration, and pH. The equilibrium perturbation reaction proceeds as a first order approach to equilibrium over a wide range of conditions, allowing the simultaneous determination of complex formation and dissociation rate constants. The rate of the complexation reaction has been determined for the entire lanthanide series (except Pm(3+)). The predominant pathway for lanthanide-EDTA and lanthanide-DTPA dissociation is inversely dependent on the total lactate concentration; the complex formation reaction demonstrates a direct dependence on [H(+)]. Unexpectedly, the rate of the complex formation reaction is seen in both ligand systems to be fastest for Gd(3+). Correlation of these results indicates that in 0.3 M lactate solutions the exchange of lanthanide ions between lactate complexes and the polyaminopolycarboxylate govern the process.

Forced-flow chromatographic determination of calcium and magnesium with continuous spectrophotometric detection

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

Arguello, M.D.

1977-12-01

Modifications to the forced-flow chromatograph include a flow-through pH monitor to continuously monitor the pH of the final effluent and an active low-pass filter to eliminate noise in the spectrophotometric detector. All separations are performed using partially sulfonated XAD-2 as the ion exchanger. Elution of calcium and magnesium is accomplished using ammonium chloride and ethylenediammonium chloride solutions. Calcium and magnesium are detected by means of Arsenazo I and PAR-ZnEDTA color-forming reagents. Other metal ions are detected by means of PAR and Chromazurol S color-forming reagents. Calcium and magnesium distribution coefficients on partially sulfonated XAD-2 as functions of ammonium chloride andmore » ethylenediammonium chloride concentration are given together with distribution coefficients of other metal ions. Methods for the selective elution of interfering metal ions prior to the elution of calcium and magnesium are described. Beryllium and aluminum are selectively eluted with sulfosalicylic acid. Those elements forming anionic chloride complexes are selectively eluted with HCl-acetone. Nickel is selectively eluted with HCl-acetone-dimethylglyoxime. Synthetic samples containing calcium and magnesium, both alone and in combination with alkali metals, strontium, barium, beryllium, aluminum, transition metals, and rare earths, are analyzed. Hard water samples are analyzed for calcium and magnesium and the results compared to those obtained by EDTA titration, atomic absorption spectroscopy, and plasma emission spectroscopy. Several clinical serum samples are analyzed for calcium and magnesium and the results compared to those obtained by atomic absorption spectroscopy.« less

Interference of medical contrast media on laboratory testing.

PubMed

Lippi, Giuseppe; Daves, Massimo; Mattiuzzi, Camilla

2014-01-01

The use of contrast media such as organic iodine molecules and gadolinium contrast agents is commonplace in diagnostic imaging. Although there is widespread perception that side effects and drug interactions may be the leading problems caused by these compounds, various degrees of interference with some laboratory tests have been clearly demonstrated. Overall, the described interference for iodinate contrast media include inappropriate gel barrier formation in blood tubes, the appearance of abnormal peaks in capillary zone electrophoresis of serum proteins, and a positive bias in assessment of cardiac troponin I with one immunoassay. The interference for gadolinium contrast agents include negative bias in calcium assessment with ortho-cresolphthalein colorimetric assays and occasional positive bias using some Arsenazo reagents, negative bias in measurement of angiotensin converting enzyme (ACE) and zinc (colorimetric assay), as well as positive bias in creatinine (Jaffe reaction), total iron binding capacity (TIBC, ferrozine method), magnesium (calmagite reagent) and selenium (mass spectrometry) measurement. Interference has also been reported in assessment of serum indices, pulse oximetry and methaemoglobin in samples of patients receiving Patent Blue V. Under several circumstances the interference was absent from manufacturer-supplied information and limited to certain type of reagents and/or analytes, so that local verification may be advisable to establish whether or not the test in use may be biased. Since the elimination half-life of these compounds is typically lower than 2 h, blood collection after this period may be a safer alternative in patients who have received contrast media for diagnostic purposes.

In-vitro analysis of early calcification in aortic valvular interstitial cells using Laser-Induced Breakdown Spectroscopy (LIBS).

PubMed

Davari, Seyyed Ali; Masjedi, Shirin; Ferdous, Zannatul; Mukherjee, Dibyendu

2018-01-01

Calcific aortic valve disease (CAVD) is a major cardiovascular disorder caused by osteogenic differentiation of valvular interstitial cells (VICs) within aortic valves. Conventional methods like colorimetric assays and histology fail to detect small calcium depositions during in-vitro VIC cultures. Laser-induced breakdown spectroscopy (LIBS) is a robust analytical tool used for inorganic materials characterizations, but relatively new to biomedical applications. We employ LIBS, for the first time, for quantitative in-vitro detection of calcium depositions in VICs at various osteogenic differentiation stages. VICs isolated from porcine aortic valves were cultured in osteogenic media over various days. Colorimetric calcium assays based on arsenazo dye and Von Kossa staining measured the calcium depositions within VICs. Simultaneously, LIBS signatures for Ca I (422.67 nm) atomic emission lines were collected for estimating calcium depositions in lyophilized VIC samples. Our results indicate excellent linear correlation between the calcium assay and our LIBS measurements. Furthermore, unlike the assay results, the LIBS results could resolve calcium signals from cell samples with as early as 2 days of osteogenic culture. Quantitatively, the LIBS measurements establish the limit of detection for calcium content in VICs to be ∼0.17±0.04 μg which indicates a 5-fold improvement over calcium assay. Picture: Quantitative LIBS enables in-vitro analysis for early stage detection of calcium deposition within aortic valvular interstitial cells (VICs). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interference of medical contrast media on laboratory testing

PubMed Central

Lippi, Giuseppe; Daves, Massimo; Mattiuzzi, Camilla

2014-01-01

The use of contrast media such as organic iodine molecules and gadolinium contrast agents is commonplace in diagnostic imaging. Although there is widespread perception that side effects and drug interactions may be the leading problems caused by these compounds, various degrees of interference with some laboratory tests have been clearly demonstrated. Overall, the described interference for iodinate contrast media include inappropriate gel barrier formation in blood tubes, the appearance of abnormal peaks in capillary zone electrophoresis of serum proteins, and a positive bias in assessment of cardiac troponin I with one immunoassay. The interference for gadolinium contrast agents include negative bias in calcium assessment with ortho-cresolphthalein colorimetric assays and occasional positive bias using some Arsenazo reagents, negative bias in measurement of angiotensin converting enzyme (ACE) and zinc (colorimetric assay), as well as positive bias in creatinine (Jaffe reaction), total iron binding capacity (TIBC, ferrozine method), magnesium (calmagite reagent) and selenium (mass spectrometry) measurement. Interference has also been reported in assessment of serum indices, pulse oximetry and methaemoglobin in samples of patients receiving Patent Blue V. Under several circumstances the interference was absent from manufacturer-supplied information and limited to certain type of reagents and/or analytes, so that local verification may be advisable to establish whether or not the test in use may be biased. Since the elimination half-life of these compounds is typically lower than 2 h, blood collection after this period may be a safer alternative in patients who have received contrast media for diagnostic purposes. PMID:24627717

Determination of synthetic ferric chelates used as fertilizers by liquid chromatography-electrospray/mass spectrometry in agricultural matrices.

PubMed

Alvarez-Fernández, Ana; Orera, Irene; Abadía, Javier; Abadía, Anunciación

2007-01-01

A high-performance liquid chromatography-electrospray ionization/mass spectrometry (time of flight) method has been developed for the simultaneous determination of synthetic Fe(III)-chelates used as fertilizers. Analytes included the seven major Fe(III)-chelates used in agriculture, Fe(III)-EDTA, Fe(III)-DTPA, Fe(III)-HEDTA, Fe(III)-CDTA, Fe(III)-o,oEDDHA, Fe(III)-o,pEDDHA, and Fe(III)-EDDHMA, and the method was validated using isotope labeled (57)Fe(III)-chelates as internal standards. Calibration curves had R values in the range 0.9962-0.9997. Limits of detection and quantification were in the ranges 3-164 and 14-945 pmol, respectively. Analyte concentrations could be determined between the limits of quantification and 25 muM (racemic and meso Fe(III)-o,oEDDHA and Fe(III)-EDDHMA) or 50 muM (Fe(III)-EDTA, Fe(III)-HEDTA, Fe(III)-DTPA, Fe(III)-CDTA and Fe(III)-o,pEDDHA). The average intraday repeatability values were approximately 0.5 and 5% for retention time and peak area, respectively, whereas the interday repeatability values were approximately 0.7 and 8% for retention time and peak area, respectively. The method was validated using four different agricultural matrices, including nutrient solution, irrigation water, soil solution, and plant xylem exudates, spiked with Fe(III)-chelate standards and their stable isotope-labeled corresponding chelates. Analyte recoveries found were in the ranges 92-101% (nutrient solution), 89-102% (irrigation water), 82-100% (soil solution), and 70-111% (plant xylem exudates). Recoveries depended on the analyte, with Fe(III)-EDTA and Fe(III)-DTPA showing the lowest recoveries (average values of 87 and 88%, respectively, for all agricultural matrices used), whereas for other analytes recoveries were between 91 and 101%. The method was also used to determine the real concentrations of Fe(III)-chelates in commercial fertilizers. Furthermore, the method is also capable of resolving two more synthetic Fe(III)-chelates, Fe(III)-EDDHSA and Fe(III)-EDDCHA, whose exact quantification is not currently possible because of lack of commercial standards.

New method for the direct determination of dissolved Fe(III) concentration in acid mine waters

USGS Publications Warehouse

To, T.B.; Nordstrom, D. Kirk; Cunningham, K.M.; Ball, J.W.; McCleskey, R. Blaine

1999-01-01

A new method for direct determination of dissolved Fe(III) in acid mine water has been developed. In most present methods, Fe(III) is determined by computing the difference between total dissolved Fe and dissolved Fe(II). For acid mine waters, frequently Fe(II) >> Fe(III); thus, accuracy and precision are considerably improved by determining Fe(III) concentration directly. The new method utilizes two selective ligands to stabilize Fe(III) and Fe(II), thereby preventing changes in Fe reduction-oxidation distribution. Complexed Fe(II) is cleanly removed using a silica-based, reversed-phase adsorbent, yielding excellent isolation of the Fe(III) complex. Iron(III) concentration is measured colorimetrically or by graphite furnace atomic absorption spectrometry (GFAAS). The method requires inexpensive commercial reagents and simple procedures that can be used in the field. Calcium(II), Ni(II), Pb(II), AI(III), Zn(II), and Cd(II) cause insignificant colorimetric interferences for most acid mine waters. Waters containing >20 mg of Cu/L could cause a colorimetric interference and should be measured by GFAAS. Cobalt(II) and Cr(III) interfere if their molar ratios to Fe(III) exceed 24 and 5, respectively. Iron(II) interferes when its concentration exceeds the capacity of the complexing ligand (14 mg/L). Because of the GFAAS elemental specificity, only Fe(II) is a potential interferent in the GFAAS technique. The method detection limit is 2 ??g/L (40 nM) using GFAAS and 20 ??g/L (0.4 ??M) by colorimetry.A new method for direct determination of dissolved Fe(III) in acid mine water has been developed. In most present methods, Fe(III) is determined by computing the difference between total dissolved Fe and dissolved Fe(II). For acid mine waters, frequently Fe(II)???Fe(III); thus, accuracy and precision are considerably improved by determining Fe(III) concentration directly. The new method utilizes two selective ligands to stabilize Fe(III) and Fe(II), thereby preventing changes in Fe reduction-oxidation distribution. Complexed Fe(II) is cleanly removed using a silica-based, reversed-phase adsorbent, yielding excellent isolation of the Fe(III) complex. Iron(III) concentration is measured colorimetrically or by graphite furnace atomic absorption spectrometry (GFAAS). The method requires inexpensive commercial reagents and simple procedures that can be used in the field. Calcium(II), Ni(II), Pb(II), Al(III), Zn(II), and Cd(II) cause insignificant colorimetric interferences for most acid mine waters. Waters containing >20 mg of Cu/L could cause a colorimetric interference and should be measured by GFAAS. Cobalt(II) and Cr(III) interfere if their molar ratios to Fe(III) exceed 24 and 5, respectively. Iron(II) interferes when its concentration exceeds the capacity of the complexing ligand (14 mg/L). Because of the GFAAS elemental specificity, only Fe(II) is a potential interferent in the GFAAS technique. The method detection limit is 2/??g/L (40 nM) using GFAAS and 20 ??g/L (0.4 ??M) by colorimetry.

Trends in heteroepitaxy of III-Vs on silicon for photonic and photovoltaic applications

NASA Astrophysics Data System (ADS)

Lourdudoss, Sebastian; Junesand, Carl; Kataria, Himanshu; Metaferia, Wondwosen; Omanakuttan, Giriprasanth; Sun, Yan-Ting; Wang, Zhechao; Olsson, Fredrik

2017-02-01

We present and compare the existing methods of heteroepitaxy of III-Vs on silicon and their trends. We focus on the epitaxial lateral overgrowth (ELOG) method as a means of achieving good quality III-Vs on silicon. Initially conducted primarily by near-equilibrium epitaxial methods such as liquid phase epitaxy and hydride vapour phase epitaxy, nowadays ELOG is being carried out even by non-equilibrium methods such as metal organic vapour phase epitaxy. In the ELOG method, the intermediate defective seed and the mask layers still exist between the laterally grown purer III-V layer and silicon. In a modified ELOG method called corrugated epitaxial lateral overgrowth (CELOG) method, it is possible to obtain direct interface between the III-V layer and silicon. In this presentation we exemplify some recent results obtained by these techniques. We assess the potentials of these methods along with the other existing methods for realizing truly monolithic photonic integration on silicon and III-V/Si heterojunction solar cells.

Nanowire-templated lateral epitaxial growth of non-polar group III nitrides

DOEpatents

Wang, George T [Albuquerque, NM; Li, Qiming [Albuquerque, NM; Creighton, J Randall [Albuquerque, NM

2010-03-02

A method for growing high quality, nonpolar Group III nitrides using lateral growth from Group III nitride nanowires. The method of nanowire-templated lateral epitaxial growth (NTLEG) employs crystallographically aligned, substantially vertical Group III nitride nanowire arrays grown by metal-catalyzed metal-organic chemical vapor deposition (MOCVD) as templates for the lateral growth and coalescence of virtually crack-free Group III nitride films. This method requires no patterning or separate nitride growth step.

Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing

DTIC Science & Technology

2017-06-16

Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing Sarah A. Blackstock Joseph O...December 2017 4. TITLE AND SUBTITLE Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III...Navy’s Phase III Study Areas as described in each Environmental Impact Statement/ Overseas Environmental Impact Statement and describes the methods

Spectrophotometric Determination of Chromium (III) with the Disodium Salt of (Ethylenediamine) tetraacetic Acid (Complexon III); DETERMINACION ESPECTROFOTOMETRICA DE CROMO (III) CON LA SAL DISODICA DEL ACIDO ETILEN-DIAMINO-TETRA-ACETICO (COMPLEXONA III)

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

Cellini, R.F.; Valiente, E.A.

1956-01-01

A spectrophotometric method for Cr (III) determination is established: hot and weak acid solutions are treated by disodium (ethylenediamine)tetraacetic acid (complexoneIII) yielding a very stable violet chelate, which follows Beer's law between 1 and 7 gamma Cr(III)/ml. These concentrations are employed in the experiences of this work. The absorption spectrum of Cr(III)-complexone-III has two maximums at 396 and 538 m mu . The maximum at 538 mu m is utilized in this method. Time, temperature, pH, and complexone-III concentration are studied and the best experimental conditions are fixed. (auth)

Methods for synthesizing semiconductor quality chalcopyrite crystals for nonlinear optical and radiation detection applications and the like

DOEpatents

Stowe, Ashley; Burger, Arnold

2016-05-10

A method for synthesizing I-III-VI.sub.2 compounds, including: melting a Group III element; adding a Group I element to the melted Group III element at a rate that allows the Group I and Group III elements to react thereby providing a single phase I-III compound; and adding a Group VI element to the single phase I-III compound under heat, with mixing, and/or via vapor transport. The Group III element is melted at a temperature of between about 200 degrees C. and about 700 degrees C. Preferably, the Group I element consists of a neutron absorber and the group III element consists of In or Ga. The Group VI element and the single phase I-III compound are heated to a temperature of between about 700 degrees C. and about 1000 degrees C. Preferably, the Group VI element consists of S, Se, or Te. Optionally, the method also includes doping with a Group IV element activator.

Methods for enhancing P-type doping in III-V semiconductor films

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

Liu, Feng; Stringfellow, Gerald; Zhu, Junyi

2017-08-01

Methods of doping a semiconductor film are provided. The methods comprise epitaxially growing the III-V semiconductor film in the presence of a dopant, a surfactant capable of acting as an electron reservoir, and hydrogen, under conditions that promote the formation of a III-V semiconductor film doped with the p-type dopant. In some embodiments of the methods, the epitaxial growth of the doped III-V semiconductor film is initiated at a first hydrogen partial pressure which is increased to a second hydrogen partial pressure during the epitaxial growth process.

Selective sensing of submicromolar iron(III) with 3,3‧,5,5‧-tetramethylbenzidine as a chromogenic probe

NASA Astrophysics Data System (ADS)

Zhang, Lufeng; Du, Jianxiu

2016-04-01

The development of highly selective and sensitive method for iron(III) detection is of great importance both from human health as well as environmental point of view. We herein reported a simple, selective and sensitive colorimetric method for the detection of Fe(III) at submicromolar level with 3,3,‧5,5‧-tetramethylbenzidine (TMB) as a chromogenic probe. It was observed that Fe(III) could directly oxidize TMB to form a blue solution without adding any extra oxidants. The reaction has a stoichiometric ratio of 1:1 (Fe(III)/TMB) as determined by a molar ratio method. The resultant color change can be perceived by the naked eye or monitored the absorbance change at 652 nm. The method allowed the measurement of Fe(III) in the range 1.0 × 10- 7-1.5 × 10- 4 mol L- 1 with a detection limit of 5.5 × 10- 8 mol L- 1. The relative standard deviation was 0.9% for eleven replicate measurements of 2.5 × 10- 5 mol L- 1 Fe(III) solution. The chemistry showed high selectivity for Fe(III) in contrast to other common cation ions. The practically of the method was evaluated by the determination of Fe in milk samples; good consistency was obtained between the results of this method and atomic absorption spectrophotometry as indicated by statistical analysis.

[Determination of iron(III) in Chinese herbal medicine and tea based on fluorescence quenching of 2,4-dichro-phenylfluorone].

PubMed

Dai, Gang; Aodeng, Gao-wa

2004-07-01

A new spectrofluorimetric method for the determination of trace amount of Fe(III) has been developed. This method is based on the fluorescence quenching of 2,4-dichro-phenylfluorone due to the formation of complex Fe(III)-DCIPF. In pH 5.2-5.9 buffer solution, Fe (III) and DCIPF react on each other to form a red complex. Its composition was established by method of continuous variations and molar-ratio as Fe(III): DCIPF = 1:4, the excitation and emission wavelengths were found to be 282 and 560 nm, respectively. There is a linear relationship in the range 4-24 ng x mL(-1) for Fe(III). This method is simple and rapid, and has been applied to the determination of trace iron in Chinese herbal medicine and tea samples with satisfactory results.

Invert biopanning: A novel method for efficient and rapid isolation of scFvs by phage display technology.

PubMed

Rahbarnia, Leila; Farajnia, Safar; Babaei, Hossein; Majidi, Jafar; Veisi, Kamal; Tanomand, Asghar; Akbari, Bahman

2016-11-01

Phage display is a prominent screening technique for development of novel high affinity antibodies against almost any antigen. However, removing false positive clones in screening process remains a challenge. The aim of this study was to develop an efficient and rapid method for isolation of high affinity scFvs by removing NSBs without losing rare specific clones. Therefore, a novel two rounds strategy called invert biopanning was developed for isolating high affinity scFvs against EGFRvIII antigen from human scFv library. The efficiency of invert biopanning method (procedure III) was analyzed by comparing with results of conventional biopanning methods (procedures I and II). According to the results of polyclonal ELISA, the second round of procedure III displayed highest binding affinity against EGFRvIII peptide accompanied by lowest NSB comparing to other two procedures. Several positive clones were identified among output phages of procedure III by monoclonal phage ELISA which displayed high affinity to EGFRvIII antigen. In conclusion, results of our study indicate that invert biopanning is an efficient method for avoiding NSBs and conservation of rare specific clones during screening of a scFv phage library. Novel anti EGFRvIII scFv isolated could be a promising candidate for potential use in treatment of EGFRvIII expressing cancers. Copyright © 2016 International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

Molecular structure and biological studies on Cr(III), Mn(II) and Fe(III) complexes of heterocyclic carbohydrazone ligand.

PubMed

Abu El-Reash, G M; El-Gammal, O A; Radwan, A H

2014-01-01

The chelating behavior of the ligand (H2APC) based on carbohydrazone core modified with pyridine end towards Cr(III), Mn(II) and Fe(III) ions have been examined. The (1)H NMR and IR data for H2APC revealed the presence of two stereoisomers syn and anti in both solid state and in solution in addition to the tautomeric versatility based on the flexible nature of the hydrazone linkage leading to varied coordination modes. The spectroscopic data confirmed that the ligand behaves as a monobasic tridentate in Cr(III) and Fe(III) complexes and as neutral tetradentate in Mn(II) complex. The electronic spectra as well as the magnetic measurements confirmed the octahedral geometry for all complexes. The bond length and angles were evaluated by DFT method using material studio program for all complexes. The thermal behavior and the kinetic parameters of degradation were determined using Coats-Redfern and Horowitz-Metzger methods. The antioxidant (DDPH and ABTS methods), anti-hemolytic and cytotoxic activities of the compounds have been screened. Cr(III) complex and H2APC showed the highest antioxidant activity using ABTS and DPPH methods. With respect to in vitro Ehrlich ascites assay, H2APC exhibited the potent activity followed by Fe(III) and Cr(III)complexes. Copyright © 2013 Elsevier B.V. All rights reserved.

Highly sensitive catalytic spectrophotometric determination of ruthenium

NASA Astrophysics Data System (ADS)

Naik, Radhey M.; Srivastava, Abhishek; Prasad, Surendra

2008-01-01

A new and highly sensitive catalytic kinetic method (CKM) for the determination of ruthenium(III) has been established based on its catalytic effect on the oxidation of L-phenylalanine ( L-Pheala) by KMnO 4 in highly alkaline medium. The reaction has been followed spectrophotometrically by measuring the decrease in the absorbance at 526 nm. The proposed CKM is based on the fixed time procedure under optimum reaction conditions. It relies on the linear relationship where the change in the absorbance (Δ At) versus added Ru(III) amounts in the range of 0.101-2.526 ng ml -1 is plotted. Under the optimum conditions, the sensitivity of the proposed method, i.e. the limit of detection corresponding to 5 min is 0.08 ng ml -1, and decreases with increased time of analysis. The method is featured with good accuracy and reproducibility for ruthenium(III) determination. The ruthenium(III) has also been determined in presence of several interfering and non-interfering cations, anions and polyaminocarboxylates. No foreign ions interfered in the determination ruthenium(III) up to 20-fold higher concentration of foreign ions. In addition to standard solutions analysis, this method was successfully applied for the quantitative determination of ruthenium(III) in drinking water samples. The method is highly sensitive, selective and very stable. A review of recently published catalytic spectrophotometric methods for the determination of ruthenium(III) has also been presented for comparison.

A capillary zone electrophoresis method for detection of Apolipoprotein C-III glycoforms and other related artifactually modified species.

PubMed

Ruel, Coralie; Morani, Marco; Bruneel, Arnaud; Junot, Christophe; Taverna, Myriam; Fenaille, François; Tran, Nguyet Thuy

2018-01-12

ApolipoproteinC-III (ApoC-III) is a human plasma glycoprotein whose O-glycosylation can be altered as a result of congenital disorders of glycosylation (CDG). ApoC-III exhibits three major glycoforms whose relative quantification is of utmost importance for the diagnosis of CDG patients. Considering the very close structures of these glycoforms and their tendency to adsorb on the capillary, a thorough optimization of capillary electrophoresis (CE) parameters including preconditioning and in-between rinsing procedures was required to efficiently separate all the ApoC-III glycoforms. Permanent coatings did not contribute to high resolution separations. A fast and reliable method based on a bare-silica capillary combining the effect of urea and diamine additives allowed to separate up to six different ApoC-III forms. We demonstrated by a combination of MALDI-TOF mass spectrometry (MS) analyses and CE of intact and neuraminidase-treated samples that this method well resolved glycoforms differing not only by their sialylation degree but also by carbamylation state, an undesired chemical modification of primary amines. This method allowed to demonstrate the carbamylation of ApoC-III glycoforms for the first time. Our CZE method proved robust and accurate with excellent intermediate precision regarding migration times (RSDs < 0.7%) while RSDs for peak areas were less than 5%. Finally, the quality of three distinct batches of commercial ApoC-III obtained from different suppliers was assessed and compared. Quite similar but highly structurally heterogeneous ApoC-III profiles were observed for these samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of WAIS-III General Ability Index Minus WMS-III memory discrepancy scores.

PubMed

Lange, Rael T; Chelune, Gordon J; Tulsky, David S

2006-09-01

Analysis of the discrepancy between intellectual functioning and memory ability has received some support as a useful means for evaluating memory impairment. In recent additions to Wechlser scale interpretation, the WAIS-III General Ability Index (GAI) and the WMS-III Delayed Memory Index (DMI) were developed. The purpose of this investigation is to develop base rate data for GAI-IMI, GAI-GMI, and GAI-DMI discrepancy scores using data from the WAIS-III/WMS-III standardization sample (weighted N = 1250). Base rate tables were developed using the predicted-difference method and two simple-difference methods (i.e., stratified and non-stratified). These tables provide valuable data for clinical reference purposes to determine the frequency of GAI-IMI, GAI-GMI, and GAI-DMI discrepancy scores in the WAIS-III/WMS-III standardization sample.

Methods and compositions for diagnosing and preventing a group B streptococcal infection

DOEpatents

Brady, Linda Jeannine [Gainesville, FL; Seifert, Kyle N [Harrisonburg, VA; Adderson, Elisabeth E [Memphis, TN; Bohnsack, John F [Salt Lake City, UT

2009-09-15

The present invention provides a group B streptococcal (GBS) surface antigen, designated epsilon antigen, that is co-expressed with the delta antigen on a subset of serotype III GBS. Epsilon is expressed on more pathogenic Restriction Digest Pattern (RDP) III-3 GBS, but not on RDP types 1, 2, or 4. Accordingly, the present invention provides compositions and methods for detecting a group B streptococcus serotype III, RDP III-3 strain. Vaccines and methods of identifying agents which inhibit adhesion of a group B streptococcal cell to a host cell are also provided.

1-(2-Formamidoethyl)-3-phenylurea functionalized activated carbon for selective solid-phase extraction and preconcentration of metal ions.

PubMed

Tu, Zhifeng; He, Qun; Chang, Xijun; Hu, Zheng; Gao, Ru; Zhang, Lina; Li, Zhenhua

2009-09-07

A novel method that utilizes 1-(2-formamidoethyl)-3-phenylurea-modified activated carbon (AC-1-(2-formamidoethyl)-3-phenylurea) as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III), Cu(II), Fe(III) and Pb(II) prior to the measurement by inductively coupled plasma atomic emission spectrometry (ICP-AES). Experimental conditions for effective adsorption of trace levels of Cr(III), Cu(II), Fe(III) and Pb(II) were optimized using batch and column procedures in detail. The optimum pH value for the separation of metal ions simultaneously on the new sorbent was 4. And the adsorbed metal ions could be completely eluted by using 2.0 mL 2.0 mol L(-1) HCl solution. Common coexisting ions did not interfere with the separation and determination of target metal ions. The maximum static adsorption capacity of the sorbent at optimum conditions was found to be 39.8, 39.9, 77.8 and 17.3 mg g(-1) for Cr(III), Cu(II), Fe(III) and Pb(II), respectively. The detection limits of the method were found to be 0.15, 0.41, 0.27 and 0.36 ng mL(-1) for Cr(III), Cu(II), Fe(III) and Pb(II), respectively. The relative standard deviation (RSD) of the method was lower than 4.0% (n=8). The method was successfully applied for the preconcentration of trace Cr(III), Cu(II), Fe(III) and Pb(II) in natural and certified samples with satisfactory results.

Dissociation kinetics of Fe(III)- and Al(III)-natural organic matter complexes at pH 6.0 and 8.0 and 25 °C

NASA Astrophysics Data System (ADS)

Jones, Adele M.; Pham, A. Ninh; Collins, Richard N.; Waite, T. David

2009-05-01

The rate at which iron- and aluminium-natural organic matter (NOM) complexes dissociate plays a critical role in the transport of these elements given the readiness with which they hydrolyse and precipitate. Despite this, there have only been a few reliable studies on the dissociation kinetics of these complexes suggesting half-times of some hours for the dissociation of Fe(III) and Al(III) from a strongly binding component of NOM. First-order dissociation rate constants are re-evaluated here at pH 6.0 and 8.0 and 25 °C using both cation exchange resin and competing ligand methods for Fe(III) and a cation exchange resin method only for Al(III) complexes. Both methods provide similar results at a particular pH with a two-ligand model accounting satisfactorily for the dissociation kinetics results obtained. For Fe(III), half-times on the order of 6-7 h were obtained for dissociation of the strong component and 4-5 min for dissociation of the weak component. For aluminium, the half-times were on the order of 1.5 h and 1-2 min for the strong and weak components, respectively. Overall, Fe(III) complexes with NOM are more stable than analogous complexes with Al(III), implying Fe(III) may be transported further from its source upon dilution and dispersion.

An improved implementable process for the synthesis of zeolite 4A from bauxite tailings and its Cr3+ removal capacity

NASA Astrophysics Data System (ADS)

Lei, Peng-cheng; Shen, Xian-jiang; Li, Yang; Guo, Min; Zhang, Mei

2016-07-01

A simple and practical method for the synthesis of zeolite 4A from bauxite tailings is presented in this paper. Systematic investigations were carried out regarding the capacity of zeolite 4A to remove Cr(III) from aqueous solutions with relatively low initial concentrations of Cr(III) (5-100 mg·L-1). It is found that the new method is extremely cost-effective and can significantly contribute in decreasing environmental pollution caused by the dumping of bauxite tailings. The Cr(III) removal capacity highly depends on the initial pH value and concentration of Cr(III) in the solution. The maximum removal capacity of Cr(III) was evaluated to be 85.1 mg·g-1 for zeolite 4A, measured at an initial pH value of 4 and an initial Cr(III) concentration of 5 mg·L-1. This approach enables a higher removal capacity at lower concentrations of Cr(III), which is a clear advantage over the chemical precipitation method. The removal mechanism of Cr(III) by zeolite 4A was examined. The results suggest that both ion exchange and the surface adsorption-crystallization reaction are critical steps. These two steps collectively resulted in the high removal capacity of zeolite 4A to remove Cr(III).

Selective solid-phase extraction using oxidized activated carbon modified with triethylenetetramine for preconcentration of metal ions

NASA Astrophysics Data System (ADS)

Zhang, Li; Chang, Xijun; Li, Zhenhua; He, Qun

2010-02-01

A new selective solid-phase extractant using activated carbon as matrix which was purified, oxidized and modified by triethylenetetramine (AC-TETA) was prepared and characterized by FT-IR spectroscopy. At pH 4, quantitative extraction of trace Cr(III), Fe(III) and Pb(II) was obtained and determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Complete elution of the adsorbed metal ions from the sorbent surface was carried out using 0.5 mol L -1 HCl. The maximum static adsorption capacity of sorbent for Cr(III), Fe(III) and Pb(II) was 34.6, 36.5 and 51.9 mg g -1, respectively. The time of quantitative adsorption was less than 2 min. The detection limits of the method was found to be 0.71, 0.35 and 0.45 ng mL -1 for Cr(III), Fe(III) and Pb(II), and the relative standard deviation (RSD) was 3.7%, 2.2% and 2.5%, respectively. Moreover, the method was free from interference with common coexiting ions. The method was also successfully applied to the preconcentration of trace Cr(III), Fe(III) and Pb(II) in synthetic samples and a real sample with satisfactory results.

A simple and rapid method for direct determination of Al(III) based on the enhanced resonance Rayleigh scattering of hemin-functionalized graphene-Al(III) system

NASA Astrophysics Data System (ADS)

Ling, Yu; Chen, Ling Xiao; Dong, Jiang Xue; Li, Nian Bing; Luo, Hong Qun

2016-03-01

A novel method for direct determination of Al(III) by using hemin-functionalized graphene (H-GO) has been established based on the enhancement of resonance Rayleigh scattering (RRS) intensity. The characteristics of RRS spectra, the optimum reaction conditions, and the reaction mechanism have been investigated. In this experiment, the Al(III) would exist in sol-gel Al(OH)3 species under the condition of pH 5.9 in aqueous solutions. When H-GO existed in the solution, the sol-gel Al(OH)3 would react with H-GO and result in enhancement of RRS intensity, owing to the enhanced hydrophobicity of H-GO surface. Therefore, a simple and rapid sensor for Al(III) was developed. The increased intensity of RRS is directly proportional to the concentration of Al(III) in the range of 10 nM-6 μM, along with a detection limit of 0.87 nM. Moreover, the sensor has been applied to determination of Al(III) concentration in real water and aspirin tablet samples with satisfactory results. Therefore, the proposed method is promising as an effective means for selective and sensitive determination of Al(III).

Determination of Grayanotoxins from Rhododendron brachycarpum in Dietary Supplements and Homemade Wine by Liquid Chromatography-Quadrupole Time-of-Flight-Mass Spectrometry and Liquid Chromatography-Tandem Mass Spectrometry.

PubMed

Hwang, Taeik; Noh, Eunyoung; Jeong, Ji Hye; Park, Sung-Kwan; Shin, Dongwoo; Kang, Hoil

2018-02-28

A sensitive and specific high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (LC-QTOF-MS) method combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of grayanotoxins I and III in dietary supplements and homemade wine. Grayanotoxins I and III were successfully extracted using solid-phase extraction cartridges, characterized by LC-QTOF-MS, and quantitated by LC-MS/MS. The LC-MS/MS calibration curves were linear over concentrations of 10-100 ng/mL (grayanotoxin I) and 20-400 ng/mL (grayanotoxin III). Grayanotoxins I and III were found in 51 foodstuffs, with quantitative determinations revealing total toxin concentrations of 18.4-101 000 ng/mL (grayanotoxin I) and 15.3-56 000 ng/mL (grayanotoxin III). The potential of the validated method was demonstrated by successful quantitative analysis of grayanotoxins I and III in dietary supplements and homemade wine; the method appears suitable for the routine detection of grayanotoxins I and III from Rhododendron brachycarpum.

Method of trivalent chromium concentration determination by atomic spectrometry

DOEpatents

Reheulishvili, Aleksandre N [Tbilisi, 0183, GE; Tsibakhashvili, Neli Ya [Tbilisi, 0101, GE

2006-12-12

A method is disclosed for determining the concentration of trivalent chromium Cr(III) in a sample. The addition of perchloric acid has been found to increase the atomic chromium spectrometric signal due to Cr(III), while leaving the signal due to hexavalent chromium Cr(VI) unchanged. This enables determination of the Cr(III) concentration without pre-concentration or pre-separation from chromium of other valences. The Cr(III) concentration may be measured using atomic absorption spectrometry, atomic emission spectrometry or atomic fluorescence spectrometry.

Method for Improving Mg Doping During Group-III Nitride MOCVD

DOEpatents

Creighton, J. Randall; Wang, George T.

2008-11-11

A method for improving Mg doping of Group III-N materials grown by MOCVD preventing condensation in the gas phase or on reactor surfaces of adducts of magnesocene and ammonia by suitably heating reactor surfaces between the location of mixing of the magnesocene and ammonia reactants and the Group III-nitride surface whereon growth is to occur.

Hypothesis testing for the validation of the kinetic spectrophotometric methods for the determination of lansoprazole in bulk and drug formulations via Fe(III) and Zn(II) chelates.

PubMed

Rahman, Nafisur; Kashif, Mohammad

2010-03-01

Point and interval hypothesis tests performed to validate two simple and economical, kinetic spectrophotometric methods for the assay of lansoprazole are described. The methods are based on the formation of chelate complex of the drug with Fe(III) and Zn(II). The reaction is followed spectrophotometrically by measuring the rate of change of absorbance of coloured chelates of the drug with Fe(III) and Zn(II) at 445 and 510 nm, respectively. The stoichiometric ratio of lansoprazole to Fe(III) and Zn(II) complexes were found to be 1:1 and 2:1, respectively. The initial-rate and fixed-time methods are adopted for determination of drug concentrations. The calibration graphs are linear in the range 50-200 µg ml⁻¹ (initial-rate method), 20-180 µg ml⁻¹ (fixed-time method) for lansoprazole-Fe(III) complex and 120-300 (initial-rate method), and 90-210 µg ml⁻¹ (fixed-time method) for lansoprazole-Zn(II) complex. The inter-day and intra-day precision data showed good accuracy and precision of the proposed procedure for analysis of lansoprazole. The point and interval hypothesis tests indicate that the proposed procedures are not biased. Copyright © 2010 John Wiley & Sons, Ltd.

Spectroscopic studies on interaction of BSA and Eu(III) complexes with H5ph-dtpa and H5dtpa ligands.

PubMed

Kong, Deyong; Qin, Cui; Fan, Ping; Li, Bing; Wang, Jun

2015-04-05

An novel aromatic aminopolycarboxylic acid ligand, N-(2-N,N-Dicarboxymethylaminophenyl) ethylenediamine-N,N',N'-triacetic acid (H5ph-dtpa), was synthesized by improving experimental method and its corresponding Eu(III) complex, Na2[EuIII(ph-dtpa)(H2O)]·6H2O, was successfully prepared through heat-refluxing method. As a comparison, the Eu(III) complex with diethylenetriamine-N,N,N',N',N″-pentaacetic acid (H5dtpa) ligand, Na2[Eu(III)(dtpa)(H2O)]·6H2O, was also prepared by the same method. And then, the interaction between prepared Eu(III) complexes ([EuIII(dtpa)(H2O)]2- and [EuIII(ph-dtpa)(H2O)]2-) and bovine serum albumin (BSA) in aqueous solution were studied by the combination of ultraviolet-visible (UV-vis), fluorescence and circular dichroism (CD) spectroscopies. In addition, the binding sites of Eu(III) complexes ([EuIII(dtpa)(H2O)]2- and [EuIII(ph-dtpa)(H2O)]2-) to BSA molecules were also estimated by synchronous fluorescence. Moreover, the theoretical and experimental results show that the Van der Waals, hydrogen bond and π-π stacking interactions are the mainly impulse to the reaction. The binding distances (r) between Eu(III) complexes ([EuIII(dtpa)(H2O)]2- and [EuIII(ph-dtpa)(H2O)]2-) and BSA were obtained according to Förster's non-radiative energy transfer theory. Also, the determined UV-vis absorption spectroscopy, synchronous fluorescence and circular dichroism (CD) spectra showed that the conformation of BSA could be changed in the presence of Eu(III) complexes. The obtained results can help understand the action mode between rare earth metal complexes of aminopolycarboxylic acid ligands with BSA and they are also expected to provide important information of designs of new inspired drugs. Copyright © 2015 Elsevier B.V. All rights reserved.

Spectroscopic studies on interaction of BSA and Eu(III) complexes with H5ph-dtpa and H5dtpa ligands

NASA Astrophysics Data System (ADS)

Kong, Deyong; Qin, Cui; Fan, Ping; Li, Bing; Wang, Jun

2015-04-01

An novel aromatic aminopolycarboxylic acid ligand, N-(2-N,N-Dicarboxymethylaminophenyl) ethylenediamine-N,N‧,N‧-triacetic acid (H5ph-dtpa), was synthesized by improving experimental method and its corresponding Eu(III) complex, Na2[EuIII(ph-dtpa)(H2O)]·6H2O, was successfully prepared through heat-refluxing method. As a comparison, the Eu(III) complex with diethylenetriamine-N,N,N‧,N‧,N″-pentaacetic acid (H5dtpa) ligand, Na2[EuIII(dtpa)(H2O)]·6H2O, was also prepared by the same method. And then, the interaction between prepared Eu(III) complexes ([EuIII(dtpa)(H2O)]2- and [EuIII(ph-dtpa)(H2O)]2-) and bovine serum albumin (BSA) in aqueous solution were studied by the combination of ultraviolet-visible (UV-vis), fluorescence and circular dichroism (CD) spectroscopies. In addition, the binding sites of Eu(III) complexes ([EuIII(dtpa)(H2O)]2- and [EuIII(ph-dtpa)(H2O)]2-) to BSA molecules were also estimated by synchronous fluorescence. Moreover, the theoretical and experimental results show that the Van der Waals, hydrogen bond and π-π stacking interactions are the mainly impulse to the reaction. The binding distances (r) between Eu(III) complexes ([EuIII(dtpa)(H2O)]2- and [EuIII(ph-dtpa)(H2O)]2-) and BSA were obtained according to Förster's non-radiative energy transfer theory. Also, the determined UV-vis absorption spectroscopy, synchronous fluorescence and circular dichroism (CD) spectra showed that the conformation of BSA could be changed in the presence of Eu(III) complexes. The obtained results can help understand the action mode between rare earth metal complexes of aminopolycarboxylic acid ligands with BSA and they are also expected to provide important information of designs of new inspired drugs.

A new turn-on fluorimetric method for the rapid speciation of Cr(III)/Cr(VI) species in tea samples with rhodamine-based fluorescent reagent

NASA Astrophysics Data System (ADS)

Özyol, Esra; Saçmacı, Şerife; Saçmacı, Mustafa; Ülgen, Ahmet

2018-02-01

A new fluorimetric method with rhodamine-based fluorescent agent was developed for the rapid speciation of Cr(III)/Cr(VI) in tea, soil and water samples. The system, which utilizes a fluorescent reagent, was used for the first time after synthesis/characterization of 3‧,6‧-bis(diethylamino)-2-{[(1E)-(2,4-dimethoxyphenyl)methylene] amino}spiro[isoindole-1,9‧-xanthen]-3(2H)-one (BDAS). The reagent responds instantaneously at room temperature in a 1:1 stoichiometric manner to the amount of Cr(III). The selectivity of this system for Cr(III) over other metal ions is remarkably high, and its sensitivity is below 0.01 mg L- 1 in aqueous solutions which enables a simplification without any pretreatment of the real sample. The method has a wide linear range of 0.1-10 mg L- 1 and a detection limit of 0.15 μg L- 1 for Cr(III) while the relative standard deviation was 0.1% for 0.1 mg L- 1 Cr(III) concentration. The results of detection and recovery experiments for Cr(III) in tea, soil and water were satisfactory, indicating that the method has better feasibility and application potential in the routine determination and speciation of Cr(III)/Cr(VI). The results of analysis of the certified reference material (INCT-TL-1 tea sample and CWW-TM-D waste water) are in good agreement with the certified value.

Molten-Salt-Based Growth of Group III Nitrides

DOEpatents

Waldrip, Karen E.; Tsao, Jeffrey Y.; Kerley, Thomas M.

2008-10-14

A method for growing Group III nitride materials using a molten halide salt as a solvent to solubilize the Group-III ions and nitride ions that react to form the Group III nitride material. The concentration of at least one of the nitride ion or Group III cation is determined by electrochemical generation of the ions.

Comparison of spectrofluorometric and HPLC methods for the characterization of fecal porphyrins in river otters.

PubMed

Taylor, C; Duffy, L K; Plumley, F G; Bowyer, R T

2000-09-01

A spectrofluorometric method (B. Grandchamp et al., 1980, Biochem. Biophys. Acta 629, 577-586) developed for the determination of amounts of uroporphyrin I (Uro I), coproporphyrin III (Copro III), and protoporphyrin IX (Proto IX) in skin fibroblasts was compared with a high-performance liquid chromatography (HPLC) method for the analysis of porphyrins in fecal samples of river otters (Lutra canadensis). Heptacarboxylate porphyrin I and coproporphyrin I, two porphyrins determined to be critical in defining the porphyrin profile in fecal samples of river otters with the HPLC method, contributed substantially to the calculation of the concentrations of Uro I and Copro III, respectively, in standard solutions of porphyrins with the spectrofluorometric method. Fluorescent components of the fecal matrix complicated the determination of the concentrations of Uro I, Copro III, and Proto IX with the spectrofluorometric method and resulted in erroneous values for the concentrations of these porphyrins compared with values determined with the HPLC method. These results indicate that the complexity of the sample, particularly with regard to the potential presence of interfering fluorescent compounds, as well as porphyrins additional to Uro I, Copro III, and Proto IX, should be considered prior to the application of the spectrofluorometric method. An alternative HPLC method developed for the rapid characterization of porphyrin profiles in fecal samples of river otters is described. Copyright 2000 Academic Press.

A novel method for blood volume estimation using trivalent chromium in rabbit models.

PubMed

Baby, Prathap Moothamadathil; Kumar, Pramod; Kumar, Rajesh; Jacob, Sanu S; Rawat, Dinesh; Binu, V S; Karun, Kalesh M

2014-05-01

Blood volume measurement though important in management of critically ill-patients is not routinely estimated in clinical practice owing to labour intensive, intricate and time consuming nature of existing methods. The aim was to compare blood volume estimations using trivalent chromium [(51)Cr(III)] and standard Evans blue dye (EBD) method in New Zealand white rabbit models and establish correction-factor (CF). Blood volume estimation in 33 rabbits was carried out using EBD method and concentration determined using spectrophotometric assay followed by blood volume estimation using direct injection of (51)Cr(III). Twenty out of 33 rabbits were used to find CF by dividing blood volume estimation using EBD with blood volume estimation using (51)Cr(III). CF is validated in 13 rabbits by multiplying it with blood volume estimation values obtained using (51)Cr(III). The mean circulating blood volume of 33 rabbits using EBD was 142.02 ± 22.77 ml or 65.76 ± 9.31 ml/kg and using (51)Cr(III) was estimated to be 195.66 ± 47.30 ml or 89.81 ± 17.88 ml/kg. The CF was found to be 0.77. The mean blood volume of 13 rabbits measured using EBD was 139.54 ± 27.19 ml or 66.33 ± 8.26 ml/kg and using (51)Cr(III) with CF was 152.73 ± 46.25 ml or 71.87 ± 13.81 ml/kg (P = 0.11). The estimation of blood volume using (51)Cr(III) was comparable to standard EBD method using CF. With further research in this direction, we envisage human blood volume estimation using (51)Cr(III) to find its application in acute clinical settings.

Metal interferences and their removal prior to the determination of As(T) and As(III) in acid mine waters by hydride generation atomic absorption spectrometry

USGS Publications Warehouse

McCleskey, R. Blaine; Nordstrom, D. Kirk; Ball, James W.

2003-01-01

Hydride generation atomic absorption spectrometry (HGAAS) is a sensitive and selective method for the determination of total arsenic (arsenic(III) plus arsenic(V)) and arsenic(III); however, it is subject to metal interferences for acid mine waters. Sodium borohydride is used to produce arsine gas, but high metal concentrations can suppress arsine production. This report investigates interferences of sixteen metal species including aluminum, antimony(III), antimony(V), cadmium, chromium(III), chromium(IV), cobalt, copper(II), iron(III), iron(II), lead, manganese, nickel, selenium(IV), selenium(VI), and zinc ranging in concentration from 0 to 1,000 milligrams per liter and offers a method for removing interfering metal cations with cation exchange resin. The degree of interference for each metal without cation-exchange on the determination of total arsenic and arsenic(III) was evaluated by spiking synthetic samples containing arsenic(III) and arsenic(V) with the potential interfering metal. Total arsenic recoveries ranged from 92 to 102 percent for all metals tested except antimony(III) and antimony(V) which suppressed arsine formation when the antimony(III)/total arsenic molar ratio exceeded 4 or the antimony(V)/total arsenic molar ratio exceeded 2. Arsenic(III) recoveries for samples spiked with aluminum, chromium(III), cobalt, iron(II), lead, manganese, nickel, selenium(VI), and zinc ranged from 84 to 107 percent over the entire concentration range tested. Low arsenic(III) recoveries occurred when the molar ratios of metals to arsenic(III) were copper greater than 120, iron(III) greater than 70, chromium(VI) greater than 2, cadmium greater than 800, antimony(III) greater than 3, antimony(V) greater than 12, or selenium(IV) greater than 1. Low recoveries result when interfering metals compete for available sodium borohydride, causing incomplete arsine production, or when the interfering metal oxidizes arsenic(III). Separation of interfering metal cations using cation-exchange prior to hydridegeneration permits accurate arsenic(III) determinations in acid mine waters containing high concentrations of interfering metals. Stabilization of the arsenic redox species for as many as 15 months is demonstrated for samples that have been properly filtered and acidified with HCl in the field. The detection limits for the method described in this report are 0.1 micrograms per liter for total arsenic and 0.8 micrograms per liter for arsenic(III).

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; arsenic speciation in natural-water samples using laboratory and field methods

USGS Publications Warehouse

Garbarino, John R.; Bednar, Anthony J.; Burkhardt, Mark R.

2002-01-01

Analytical methods for the determination of arsenite [As(III)], arsenate [As(V)], dimethylarsinate (DMA), monomethylarsonate (MMA), and roxarsone in filtered natural-water samples are described. Various analytical methods can be used for the determination, depending on the arsenic species being determined. Arsenic concentration is determined by using inductively coupled plasma-mass spectrometry (ICP-MS) as an arsenic-specific detector for all methods. Laboratory-speciation methods are described that use an ion chromatographic column to separate the arsenic species; the column length, column packing, and mobile phase are dependent on the species of interest. Regardless of the separation technique, the arsenic species are introduced into plasma by eithe rpneumatic nebulization or arsine generation. Analysis times range from 2 to 8 minutes and method detection limits range from 0.1 to 0.6 microgram-arsenic per liter (ug-As/L), 10 to 60 picograms absolute (for a 100-microliter injection), depending on the arsenic species determined and the analytical method used. A field-generation specciation method also is described that uses a strong anion exchange cartridge to separate As(III) from As(V) in the field. As(III) in the eluate and the As(V) in the cartridge extract are determined by direct nebulization ICP-MS. Methylated arsenic species that also are retained on the cartridge will positively bias As(V) results without further laboratory separations. The method detection limit for field speciation is 0.3 ug-As/L. The distribution of arsenic species must be preserved in the field to eliminate changes caused by photochemical oxidation or metal oxyhydroxide precipitation. Preservation techniques, such as refrigeration, the addition of acides, or the additoin of ethylene-diaminetetraacetic acid (EDTA) and the effects of ambient light were tested. Of the preservatives evaluated, EDTA was found to work best with the laboratory- and field-speciation methods for all sample matrices tested. Storing the samples in opaque polytethylene bottles eliminated the effects of photochemical oxidation. The percentage change in As(III):As(V) ratios for an EDTA-preserved acid mine drainage (AMD) sample and ground-water sample during a 3-month period was -5 percent and +3 percent, respectively. The bias and variability of the methods were evaluated by comparing results for total arsenic and As(III), As(V), DMA, and MMA concentrations in ground water, AMD, and surface water. Seventy-one ground-water, 10 AMD, and 24 surface-water samples were analyzed. Concentrations in ground-water samples reached 720 ug-As/L for As(III) and 1080 ug-As/L for As(V); AMD samples reached 12800 ug-As/L for As(III) and 7050 ug-As/L for As(V); and surface-water samples reached 5 ug-As/L for As(III) and As(V). Inorganic arsenic species distribution in the samples ranged from 0 to 90 percent As(III). DMA and MMA were present only in surface-water samples from agricultural areas where the herbicide monosodium methylarsonate was applied; concentrations never exceeded 6 ug-As/L. Statistical analyses indicated that the difference between As(III) and As(V) concentrations for samples preserved with EDTA in opaque bottles and field-speciation results were analytically insignificant at the 95-percent confidence interval. There was no significant difference among the methods tested for total arsenic concentration. Percentage recovery for field samples spiked at 50 ug-As/L and analyzed by the laboratory-speciation method (n=2) ranged from 82 to 100 percent for As(III), 97 to 102 percent for As(V), 90 to 104 percent for DMA, and 81 to 96 percent for MMA; recoveries for samples spiked at 100 ug-As/L and analyzed by the field-speciation method ranged from 102 to 107 percent for As(III) and 105 to 106 percent for As(V). Laboratory-speciation results for Environment Canada reference material SLRS-2 closely matched reported concentrations. Laboratory-speciation metho

The facile flow-injection spectrophotometric detection of gold(III) in water and pharmaceutical samples using 3,5-dimethoxy-4-hydroxy-2-aminoacetophenone isonicotinoyl hydrazone (3,5-DMHAAINH).

PubMed

Babu, S Hari; Suvardhan, K; Kumar, K Suresh; Reddy, K M; Rekha, D; Chiranjeevi, P

2005-04-11

A simple, sensitive and rapid flow-injection spectrophotometric method was developed for the determination of trace amounts of Au(III) in aqueous dimethylformamide (DMF). The method is based on formation of Au(III)-(3,5-DMHAAINH)3 complex. The optimum conditions for the chromogenic reaction of Au(III) with 3,5-DMHAAINH is studied and the colored (reddish brown) complex is selectively monitored at lambda(max) 490 nm at pH 6.0. The reaction and flow conditions of the full experimental design were optimized. The detection limit (2 s) of 0.1 microg l-1 Au(III) was obtained at a sampling rate of 15 samples h-1. Beer's law is obeyed over the range of 0.30-4.00 microg ml-1. The molar absorptivity and Sandell's sensitivity were 3.450x10(4) M and 0.0050 microg ml-1, respectively. Job's method of continuous variation and stability constants corresponding to these maxima was determined and found to be 9.3x10(15) (1:3, M:R) (M, metal; R, reagent). The detailed study of various interferences confirmed the high selectivity of the developed method. The method was successfully applied for the determination of trace amount of Au(III) in water and pharmaceutical samples. The results obtained were in agreement with the reported methods at the 95% confidence level.

Selective adsorption and recovery of Au(III) from three kinds of acidic systems by persimmon residual based bio-sorbent: a method for gold recycling from e-wastes.

PubMed

Fan, Ruiyi; Xie, Feng; Guan, Xueliang; Zhang, Qinglin; Luo, Zhengrong

2014-07-01

A low cost bio-sorbent, named "PPF resin", was prepared by crosslinking the persimmon residual with formaldehyde. The adsorption behavior of PPF resin towards Au(III) from varied HCl and HNO3 concentration solutions was studied. PPF resin could adsorb almost complete Au(III) from high acidic systems. The influence of dilution ratio, solid-liquid ratio and time towards Au(III) from aqua regia leached PCBs liquor was censored in detail by batch and continuous adsorption methods. The PPF resin before and after adsorption was characterized by FT-IR, XRD and XPS spectra which provided evidences for the reduction of Au(III) to Au(0) with a proposed mechanism of Au(III) adsorption-reduction process. After saturated column adsorption of 0.1g PPF resin, 0.0506 g gold (purity: 99.9%) was obtained by the method of incineration. The present results provide a new approach for gold recovery from the secondary resources. Copyright © 2014 Elsevier Ltd. All rights reserved.

Co(III) as mediator in phenol destruction using electrochemical oxidation

NASA Astrophysics Data System (ADS)

Herlina, Herlina; Derlini, Derlini; Muhammad, Razali

2017-03-01

Mediated electrochemical oxidation is one of the method for oxidation of organic compound by using a mediator. This method has been developed because have several advantages which low cost and efficient, the exhaust gas does not contain toxic materials and hazardous waste and the process take place at a relatively low temperature. Electrochemical oxidation of organic compounds using metal ion mediator is one alternative method that is appropriate for the treatment of organic waste. Co(III) is a strong oxidizing agent used as a mediator has been prepared in Pt electrodes. The concentration of Co(III) formed during oxidation determined by potentiometric titration where Co(III) aliquot was added into Fe(II) excess solution and the remaining Fe(II) which did not react has been titrated with Ce(IV). In optimum condition, Co(III) was then used to oxidize the organic compound into carbon dioxide. The parameters has been studied are the standard oxidation potential of mediator, acid concentration and temperature. The results obtained at potential of 6 Volt, with nitric acid 4 M and temperature of 25°C give result 23.86% where Co (II) is converted to Co(III) within 2 hours. The addition of silver nitrate can increase the concentration of Co(III). At the optimum conditions, the mediator ion Co(III) can destructed to 66.44% of phenol compound oxidized into carbon dioxide.

Contraceptive use and the role of contraceptive counseling in reproductive-aged women with cancer.

PubMed

Maslow, Bat-Sheva L; Morse, Christopher B; Schanne, Allison; Loren, Alison; Domchek, Susan M; Gracia, Clarisa R

2014-07-01

Few data on contraceptive choices in women with cancer exist. Contraception is challenging for women with cancer, particularly those with breast cancer, who are limited to nonhormonal methods. This study characterized contraceptive use during cancer treatment in a group of reproductive-aged women with a recent cancer diagnosis and assessed the impact of contraceptive counseling on the methods they selected. Cross-sectional, survey study of reproductive-aged women at a large tertiary care health system with a recent cancer diagnosis. A total of 107 women completed the survey. Eighty-two women reported 101 contraceptive choices. Twenty-seven percent (27/101) of all methods selected were Tier I/II, and 35% (35/101) were Tier III/IV. Only 4 used an intrauterine device (IUD). Among women reporting sexual activity after diagnosis, 19 (27%) of 71 reported using Tier I/II methods, 21 (30%) of 71 reported using Tier III/IV methods, 16 (23%) of 71 reported abstinence and 10 (14%) of 71 reported using no method. Factors significantly associated with Tier I/II use in the multivariable model included not having a college degree [odds ratio (OR) 0.21, 95% confidence interval (CI) 0.05-0.92, p=.038], intercourse during treatment (OR 5.92, 95% CI 1.48-23.66, p=.012) and non-breast cancer (OR 3.60, 95% CI 1.03-12.64, p=.046). Report of contraceptive counseling was positively associated with Tier I/II contraceptive use during cancer treatment (OR 6.92, 95% CI 1.14-42.11, p=.036). Reproductive-aged women diagnosed with cancer underutilized Tier I/II contraceptive agents, especially IUDs. Contraceptive counseling by physicians increases contraceptive use, particularly methods most effective at preventing pregnancy. The study uniquely described the contraceptive practices of over 100 women with cancer. The study sample commonly reported abstinence and use of contraceptive methods with high failure rates. Our data suggest that contraceptive counseling from a health care provider may increase use of more effective methods among women with cancer. Copyright © 2014 Elsevier Inc. All rights reserved.

Synthesis procedure optimization and characterization of europium (III) tungstate nanoparticles

NASA Astrophysics Data System (ADS)

Rahimi-Nasrabadi, Mehdi; Pourmortazavi, Seied Mahdi; Ganjali, Mohammad Reza; Reza Banan, Ali; Ahmadi, Farhad

2014-09-01

Taguchi robust design as a statistical method was applied for the optimization of process parameters in order to tunable, facile and fast synthesis of europium (III) tungstate nanoparticles. Europium (III) tungstate nanoparticles were synthesized by a chemical precipitation reaction involving direct addition of europium ion aqueous solution to the tungstate reagent solved in an aqueous medium. Effects of some synthesis procedure variables on the particle size of europium (III) tungstate nanoparticles were studied. Analysis of variance showed the importance of controlling tungstate concentration, cation feeding flow rate and temperature during preparation of europium (III) tungstate nanoparticles by the proposed chemical precipitation reaction. Finally, europium (III) tungstate nanoparticles were synthesized at the optimum conditions of the proposed method. The morphology and chemical composition of the prepared nano-material were characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, FT-IR spectroscopy and fluorescence.

Methods for forming group III-arsenide-nitride semiconductor materials

NASA Technical Reports Server (NTRS)

Major, Jo S. (Inventor); Welch, David F. (Inventor); Scifres, Donald R. (Inventor)

2002-01-01

Methods are disclosed for forming Group III-arsenide-nitride semiconductor materials. Group III elements are combined with group V elements, including at least nitrogen and arsenic, in concentrations chosen to lattice match commercially available crystalline substrates. Epitaxial growth of these III-V crystals results in direct bandgap materials, which can be used in applications such as light emitting diodes and lasers. Varying the concentrations of the elements in the III-V crystals varies the bandgaps, such that materials emitting light spanning the visible spectra, as well as mid-IR and near-UV emitters, can be created. Conversely, such material can be used to create devices that acquire light and convert the light to electricity, for applications such as full color photodetectors and solar energy collectors. The growth of the III-V crystals can be accomplished by growing thin layers of elements or compounds in sequences that result in the overall lattice match and bandgap desired.

Methods for forming group III-V arsenide-nitride semiconductor materials

NASA Technical Reports Server (NTRS)

Major, Jo S. (Inventor); Welch, David F. (Inventor); Scifres, Donald R. (Inventor)

2000-01-01

Methods are disclosed for forming Group III--arsenide-nitride semiconductor materials. Group III elements are combined with group V elements, including at least nitrogen and arsenic, in concentrations chosen to lattice match commercially available crystalline substrates. Epitaxial growth of these III-V crystals results in direct bandgap materials, which can be used in applications such as light emitting diodes and lasers. Varying the concentrations of the elements in the III-V crystals varies the bandgaps, such that materials emitting light spanning the visible spectra, as well as mid-IR and near-UV emitters, can be created. Conversely, such material can be used to create devices that acquire light and convert the light to electricity, for applications such as full color photodetectors and solar energy collectors. The growth of the III-V crystals can be accomplished by growing thin layers of elements or compounds in sequences that result in the overall lattice match and bandgap desired.

Chemically-modified activated carbon with ethylenediamine for selective solid-phase extraction and preconcentration of metal ions.

PubMed

Li, Zhenhua; Chang, Xijun; Zou, Xiaojun; Zhu, Xiangbing; Nie, Rong; Hu, Zheng; Li, Ruijun

2009-01-26

A new method that utilizes ethylenediamine-modified activated carbon (AC-EDA) as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III), Fe(III), Hg(II) and Pb(II) prior to the measurement by inductively coupled plasma optical emission spectrometry (ICP-OES). The new sorbent was prepared by oxidative surface modification. Experimental conditions for effective adsorption of trace levels of Cr(III), Fe(III), Hg(II) and Pb(II) were optimized with respect to different experimental parameters using batch and column procedures in detail. The optimum pH value for the separation of metal ions simultaneously on the new sorbent was 4.0. Complete elution of absorbed metal ions from the sorbent surface was carried out using 3.0 mL of 2% (%w/w) thiourea and 0.5 mol L(-1) HCl solution. Common coexisting ions did not interfere with the separation and determination of target metal ions. The maximum static adsorption capacity of the sorbent at optimum conditions was found to be 39.4, 28.9, 60.5 and 49.9 mg g(-1) for Cr(III), Fe(III), Hg(II) and Pb(II), respectively. The time for 94% adsorption of target metal ions was less than 2 min. The detection limits of the method was found to be 0.28, 0.22, 0.09 and 0.17 ng mL(-1) for Cr(III), Fe(III), Hg(II) and Pb(II), respectively. The precision (R.S.D.) of the method was lower 4.0% (n=8). The prepared sorbent as solid-phase extractant was successfully applied for the preconcentration of trace Cr(III), Fe(III), Hg(II) and Pb(II) in natural and certified samples with satisfactory results.

Prediction of future uniform milk prices in Florida federal milk marketing order 6 from milk futures markets.

PubMed

De Vries, A; Feleke, S

2008-12-01

This study assessed the accuracy of 3 methods that predict the uniform milk price in Federal Milk Marketing Order 6 (Florida). Predictions were made for 1 to 12 mo into the future. Data were from January 2003 to May 2007. The CURRENT method assumed that future uniform milk prices were equal to the last announced uniform milk price. The F+BASIS and F+UTIL methods were based on the milk futures markets because the futures prices reflect the market's expectation of the class III and class IV cash prices that are announced monthly by USDA. The F+BASIS method added an exponentially weighted moving average of the difference between the class III cash price and the historical uniform milk price (also known as basis) to the class III futures price. The F+UTIL method used the class III and class IV futures prices, the most recently announced butter price, and historical utilizations to predict the skim milk prices, butterfat prices, and utilizations in all 4 classes. Predictions of future utilizations were made with a Holt-Winters smoothing method. Federal Milk Marketing Order 6 had high class I utilization (85 +/- 4.8%). Mean and standard deviation of the class III and class IV cash prices were $13.39 +/- 2.40/cwt (1 cwt = 45.36 kg) and $12.06 +/- 1.80/cwt, respectively. The actual uniform price in Tampa, Florida, was $16.62 +/- 2.16/cwt. The basis was $3.23 +/- 1.23/cwt. The F+BASIS and F+UTIL predictions were generally too low during the period considered because the class III cash prices were greater than the corresponding class III futures prices. For the 1- to 6-mo-ahead predictions, the root of the mean squared prediction errors from the F+BASIS method were $1.12, $1.20, $1.55, $1.91, $2.16, and $2.34/cwt, respectively. The root of the mean squared prediction errors ranged from $2.50 to $2.73/cwt for predictions up to 12 mo ahead. Results from the F+UTIL method were similar. The accuracies of the F+BASIS and F+UTIL methods for all 12 fore-cast horizons were not significantly different. Application of the modified Mariano-Diebold tests showed that no method included all the information contained in the other methods. In conclusion, both F+BASIS and F+UTIL methods tended to more accurately predict the future uniform milk prices than the CURRENT method, but prediction errors could be substantial even a few months into the future. The majority of the prediction error was caused by the inefficiency of the futures markets to predict the class III cash prices.

Training Methodology. Part III: Instructional Methods and Techniques. An Annotated Bibliography. Public Health Service Publication No. 1862, Part III.

ERIC Educational Resources Information Center

Health Services and Mental Health Administration (DHEW), Bethesda, MD.

A total of 345 annotated references pertaining to instructional methods and techniques are organized under the following headings: (1) Methods and Techniques (General), (2) Job Instruction, (3) Apprenticeship, (4) Demonstration, (5) Coaching, (6) Internship, Field Work, Supervised Professional Practice, (7) Correspondence Study, (8) Independent…

Methods for improved growth of group III nitride buffer layers

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

Melnik, Yurity; Chen, Lu; Kojiri, Hidehiro

Methods are disclosed for growing high crystal quality group III-nitride epitaxial layers with advanced multiple buffer layer techniques. In an embodiment, a method includes forming group III-nitride buffer layers that contain aluminum on suitable substrate in a processing chamber of a hydride vapor phase epitaxy processing system. A hydrogen halide or halogen gas is flowing into the growth zone during deposition of buffer layers to suppress homogeneous particle formation. Some combinations of low temperature buffers that contain aluminum (e.g., AlN, AlGaN) and high temperature buffers that contain aluminum (e.g., AlN, AlGaN) may be used to improve crystal quality and morphologymore » of subsequently grown group III-nitride epitaxial layers. The buffer may be deposited on the substrate, or on the surface of another buffer. The additional buffer layers may be added as interlayers in group III-nitride layers (e.g., GaN, AlGaN, AlN).« less

Process for preparing group Ib-IIIa-VIa semiconducting films

DOEpatents

Birkmire, Robert W.; Schultz, Jerold M.; Marudachalam, Matheswaran; Hichri, Habib

1997-01-01

Methods are provided for the production of supported monophasic group I-III-VI semiconductor films. In the subject methods, a substrate is coated with group I and III elements and then contacted with a reactive group VI element containing atmosphere under conditions sufficient to produce a substrate coated with a composite of at least two different group I-III-IV alloys. The resultant composite coated substrate is then annealed in an inert atmosphere under conditions sufficient to convert the composite coating to a monophasic group I-III-VI semiconductor film. The resultant supported semiconductor films find use in photovoltaic applications, particularly as absorber layers in solar cells.

Process for preparing group Ib-IIIa-VIa semiconducting films

DOEpatents

Birkmire, R.W.; Schultz, J.M.; Marudachalam, M.; Hichri, H.

1997-10-07

Methods are provided for the production of supported monophasic group I-III-VI semiconductor films. In the subject methods, a substrate is coated with group I and III elements and then contacted with a reactive group VI element containing atmosphere under conditions sufficient to produce a substrate coated with a composite of at least two different group I-III-IV alloys. The resultant composite coated substrate is then annealed in an inert atmosphere under conditions sufficient to convert the composite coating to a monophasic group I-III-VI semiconductor film. The resultant supported semiconductor films find use in photovoltaic applications, particularly as absorber layers in solar cells. 4 figs.

Chemometrics-assisted simultaneous determination of cobalt(II) and chromium(III) with flow-injection chemiluminescence method

NASA Astrophysics Data System (ADS)

Li, Baoxin; Wang, Dongmei; Lv, Jiagen; Zhang, Zhujun

2006-09-01

In this paper, a flow-injection chemiluminescence (CL) system is proposed for simultaneous determination of Co(II) and Cr(III) with partial least squares calibration. This method is based on the fact that both Co(II) and Cr(III) catalyze the luminol-H 2O 2 CL reaction, and that their catalytic activities are significantly different on the same reaction condition. The CL intensity of Co(II) and Cr(III) was measured and recorded at different pH of reaction medium, and the obtained data were processed by the chemometric approach of partial least squares. The experimental calibration set was composed with nine sample solutions using orthogonal calibration design for two component mixtures. The calibration curve was linear over the concentration range of 2 × 10 -7 to 8 × 10 -10 and 2 × 10 -6 to 4 × 10 -9 g/ml for Co(II) and Cr(III), respectively. The proposed method offers the potential advantages of high sensitivity, simplicity and rapidity for Co(II) and Cr(III) determination, and was successfully applied to the simultaneous determination of both analytes in real water sample.

The Synthesis of 1,1’-Bicobaltocene Salts of Tetracyano-P-Quinodimethanide and the Sturcture of 1,1’-Bicobaltocene (Co (III) Co (III)) (TCNQ)3,

DTIC Science & Technology

1981-06-03

Salts of Bicobaltocenet-The hexafluorophosphate salt of bicobaltocene(III,III) was prepared by the method of Davison and Smart 4 and the orange product...tetrahydrofuran. The lithium salt of TCNO was prepared by adding a boiling solution of lithium iodide in acetonitrile to a boiling solution of TCNQ in...compound 1,1’-bicobaltocene[Co(III)Co(III)[TCNQJ 3 resulted from the reaction of the mixed valence hexafluorophosphate salt with a mixture of [Et3NH

Catalysts and methods for ring opening metathesis polymerization

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

Schrock, Richard Royce; Autenrieth, Benjamin

The present invention, among other things, provides highly syndiotactic poly(dicyclopentadiene) and/or hydrogenated poly(dicyclopentadiene), compositions thereof, and compounds and methods for preparing the same. In some embodiments, a provided compound is a compound of formula I, II or III. In some embodiments, a provided method comprises providing a compound of formula I, II or III.

Nonaqueous System of Iron-Based Ionic Liquid and DMF for the Oxidation of Hydrogen Sulfide and Regeneration by Electrolysis.

PubMed

Guo, Zhihui; Zhang, Tingting; Liu, Tiantian; Du, Jun; Jia, Bing; Gao, Shujing; Yu, Jiang

2015-05-05

To improve the hydrogen sulfide removal efficiency with the application of an iron-based imidazolium chloride ionic liquid (Fe(III)-IL) as desulfurizer, Fe(II) and N,N-dimethylformamide (DMF) are introduced to Fe(III)-IL to construct a new nonaqueous desulfurization system (Fe(III/II)-IL/DMF). Following desulfurization, the system can be regenerated using the controlled-potential electrolysis method. The addition of Fe(II) in Fe(III)-IL is beneficial for the hydrogen sulfide removal and the electrochemical regeneration of the desulfurizer. The addition of DMF in Fe(III/II)-IL does not change the structure of Fe(III/II)-IL but clearly decreases the acidity, increases the electrolytic current, and decreases the stability of the Fe-Cl bond in Fe(III/II)-IL. Fe(III/II)-IL/DMF can remove hydrogen sulfide and can be regenerated through an electrochemical method more efficiently than can Fe(III/II)-IL. After six cycles, the desulfurization efficiency remains higher than 98%, and the average conversion rate of Fe(II) is essentially unchanged. No sulfur peroxidation occurs, and the system remains stable. Therefore, this new nonaqueous system has considerable potential for removing H2S in pollution control applications.

Development and Implementation of Efficiency-Improving Analysis Methods for the SAGE III on ISS Thermal Model Originating

NASA Technical Reports Server (NTRS)

Liles, Kaitlin; Amundsen, Ruth; Davis, Warren; Scola, Salvatore; Tobin, Steven; McLeod, Shawn; Mannu, Sergio; Guglielmo, Corrado; Moeller, Timothy

2013-01-01

The Stratospheric Aerosol and Gas Experiment III (SAGE III) instrument is the fifth in a series of instruments developed for monitoring aerosols and gaseous constituents in the stratosphere and troposphere. SAGE III will be delivered to the International Space Station (ISS) via the SpaceX Dragon vehicle in 2015. A detailed thermal model of the SAGE III payload has been developed in Thermal Desktop (TD). Several novel methods have been implemented to facilitate efficient payload-level thermal analysis, including the use of a design of experiments (DOE) methodology to determine the worst-case orbits for SAGE III while on ISS, use of TD assemblies to move payloads from the Dragon trunk to the Enhanced Operational Transfer Platform (EOTP) to its final home on the Expedite the Processing of Experiments to Space Station (ExPRESS) Logistics Carrier (ELC)-4, incorporation of older models in varying unit sets, ability to change units easily (including hardcoded logic blocks), case-based logic to facilitate activating heaters and active elements for varying scenarios within a single model, incorporation of several coordinate frames to easily map to structural models with differing geometries and locations, and streamlined results processing using an Excel-based text file plotter developed in-house at LaRC. This document presents an overview of the SAGE III thermal model and describes the development and implementation of these efficiency-improving analysis methods.

Th(As(III)4As(V)4O18): a mixed-valent oxoarsenic(III)/arsenic(V) actinide compound obtained under extreme conditions.

PubMed

Yu, Na; Klepov, Vladislav V; Kegler, Philip; Bosbach, Dirk; Albrecht-Schmitt, Thomas E; Alekseev, Evgeny V

2014-08-18

A high-temperature/high-pressure method was employed to investigate phase formation in the Th(NO3)4·5H2O-As2O3-CsNO3 system. It was observed that an excess of arsenic(III) in starting system leads to the formation of Th(As(III)4As(V)4O18), which is representative of a rare class of mixed-valent arsenic(III)/arsenic(V) compounds. This compound was studied with X-ray diffraction, energy-dispersive X-ray, and Raman spectroscopy methods. Crystallographic data show that Th(As(III)4As(V)4O18) is built from (As(III)4As(V)4O18)(4-) layers connected through Th atoms. The arsenic layers are found to be isoreticular to those in previously reported As2O3 and As3O5(OH), and the geometric differences between them are discussed. Bands in the Raman spectrum are assigned with respect to the presence of AsO3 and AsO4 groups.

Field and laboratory arsenic speciation methods and their application to natural-water analysis

USGS Publications Warehouse

Bednar, A.J.; Garbarino, J.R.; Burkhardt, M.R.; Ranville, J.F.; Wildeman, T.R.

2004-01-01

The toxic and carcinogenic properties of inorganic and organic arsenic species make their determination in natural water vitally important. Determination of individual inorganic and organic arsenic species is critical because the toxicology, mobility, and adsorptivity vary substantially. Several methods for the speciation of arsenic in groundwater, surface-water, and acid mine drainage sample matrices using field and laboratory techniques are presented. The methods provide quantitative determination of arsenite [As(III)], arsenate [As(V)], monomethylarsonate (MMA), dimethylarsinate (DMA), and roxarsone in 2-8min at detection limits of less than 1??g arsenic per liter (??g AsL-1). All the methods use anion exchange chromatography to separate the arsenic species and inductively coupled plasma-mass spectrometry as an arsenic-specific detector. Different methods were needed because some sample matrices did not have all arsenic species present or were incompatible with particular high-performance liquid chromatography (HPLC) mobile phases. The bias and variability of the methods were evaluated using total arsenic, As(III), As(V), DMA, and MMA results from more than 100 surface-water, groundwater, and acid mine drainage samples, and reference materials. Concentrations in test samples were as much as 13,000??g AsL-1 for As(III) and 3700??g AsL-1 for As(V). Methylated arsenic species were less than 100??g AsL-1 and were found only in certain surface-water samples, and roxarsone was not detected in any of the water samples tested. The distribution of inorganic arsenic species in the test samples ranged from 0% to 90% As(III). Laboratory-speciation method variability for As(III), As(V), MMA, and DMA in reagent water at 0.5??g AsL-1 was 8-13% (n=7). Field-speciation method variability for As(III) and As(V) at 1??g AsL-1 in reagent water was 3-4% (n=3). ?? 2003 Elsevier Ltd. All rights reserved.

Trivalent chromium solubility and its influence on quantification of hexavalent chromium in ambient particulate matter using EPA method 6800.

PubMed

Huang, Lihui; Yu, Chang Ho; Hopke, Philip K; Shin, Jin Young; Fan, Zhihua

2014-12-01

Measurement of carcinogenic Cr(VI) in ambient PM is challenging due to potential errors associated with conversion between Cr (VI) (a carcinogen) and Cr(III) (an essential nutrient). Cr(III) conversion is a particular concern due to its > 80% atomic abundance in total Cr. US. Environmental Protection Agency (EPA) method 6800 that uses water-soluble isotope spikes can be used to correct the interconversion. However, whether the enriched Cr(III) isotope spikes can adequately mimic the Cr(III) species originally in ambient PM is unknown. This study examined the water solubility of Cr(III) in ambient PM and discussed its influence on Cr(VI) measurement. Ambient PM10 samples were collected on Teflon filters at four sites in New Jersey that may have different Cr emission sources. The samples were ultrasonically extracted with 5 mL DI-H2O (pH 5.7) at room temperature for 40 min, and then analyzed by ion chromatography-inductively coupled plasma mass spectrometry (IC-ICPMS). Cr(III) was below detection limit (0.06 ng/m3) for all samples, suggesting water-soluble Cr(III) species, such as CrCl3, Cr(NO3)3, and amorphous Cr(OH)3, in the ambient PM were negligible. Therefore, the enriched 50Cr(III) isotope spike (in the form of Cr(NO3)3) could not mimic the original ambient Cr(III). Only the conversion of 53Cr(VI) (in the form of K2CrO4) was taken into account when correcting the interconversion. We then used NaHCO3-pretreated MCE filters (prespiked with enriched isotope species) to measure Cr(VI) in the ambient PM10. The samples were ultrasonically extracted at 60 C pH 9 solutions for 40 min followed by IC-ICPMS analysis. Due to the correction of Cr(VI) reduction, the Cr(VI) concentrations determined by EPA method 6800, 0.26 ± 0.16 (summer) and 0.16 ± 0.11(winter) ng/m3 (n = 64), were significantly greater than those by the external standard curve, 0.21 ± 0.17 (summer) and 0.10 ± 0.07 (winter) ng/m3 (n = 56) (p < 0.01, Student's t-test). Our study revealed that appropriate application of EPA method 6800 is important because it only applies to soluble fraction of Cr species in ambient PM. Implications: Accurate measurement of carcinogenic Cr(VI) in ambient PM is challenging due to conversion between Cr(VI) (a human carcinogen) and Cr(III) (a human essential nutrient). The conversion of CR(III) is of particular concern due to its dominant presence in total Cr (>80%). This study examined the water solubility of Cr(III) in ambient PM that was collected at four locations in New Jersey. Then we discussed the influence of Cr(III) solubility on the application of EPA method 6800, which utilizes enriched isotope spikes to correct the interconversion. Our results suggested that appropriate application of EPA method 6800 is important because it only applies to soluble fraction of Cr species.

Sensitized spectrophotometric determination of Cr(III) ion for speciation of chromium ion in surfactant media using alpha-benzoin oxime.

PubMed

Ghaedi, Mehrorang; Asadpour, Enayat; Vafaie, Azam

2006-01-01

A simple and accurate micellanized spectrophotometric method for determination of trace amounts of Cr(III) ion in tab and top water and a synthetic mixture has been described. The micellar method is based on effect of organized molecular assemblies such as micelles in spectrophotometric measurement due to their effect on the systems of interest. The ability of micellar system in solubilizing of sparingly soluble ligand or complexes has been used for increasing figures of merit of an analytical method. Due to solubility increasing in aqueous media requirement for a primary extraction can be eliminated. Using the alpha-benzoin oxime (alpha-BO) spectrophotometric determination of Cr(III) ion has been performed and results are compared. The spectrophotometric determination of Cr(III) ion using alpha-BO in the presence of non-ionic surfactant Triton X-100 has been performed. The influence of type and amount of surfactant, pH, complexation time and amount of ligand were examined. Finally, the repeatability, accuracy and the effect of interfering ions on the determination of Cr(III) ion was evaluated. The proposed methods successfully with recovery yield of almost 100% have been applied to the rapid and simple determination of Cr(III) ion in the real samples. There is a good agreement between methods and atomic absorption spectrometry. The Beers law is obeyed over the concentration range of 0.1-13.7 microg mL(-1) for micellar media. The detection limit is 0.8 ng mL(-1). The molar absorptivity of complex is 5350 L mol(-1) cm(-1).

Sensitized spectrophotometric determination of Cr(III) ion for speciation of chromium ion in surfactant media using α-benzoin oxime

NASA Astrophysics Data System (ADS)

Ghaedi, Mehrorang; Asadpour, Enayat; Vafaie, Azam

2006-01-01

A simple and accurate micellanized spectrophotometric method for determination of trace amounts of Cr(III) ion in tab and top water and a synthetic mixture has been described. The micellar method is based on effect of organized molecular assemblies such as micelles in spectrophotometric measurement due to their effect on the systems of interest. The ability of micellar system in solubilizing of sparingly soluble ligand or complexes has been used for increasing figures of merit of an analytical method. Due to solubility increasing in aqueous media requirement for a primary extraction can be eliminated. Using the α-benzoin oxime (α-BO) spectrophotometric determination of Cr(III) ion has been performed and results are compared. The spectrophotometric determination of Cr(III) ion using α-BO in the presence of non-ionic surfactant Triton X-100 has been performed. The influence of type and amount of surfactant, pH, complexation time and amount of ligand were examined. Finally, the repeatability, accuracy and the effect of interfering ions on the determination of Cr(III) ion was evaluated. The proposed methods successfully with recovery yield of almost 100% have been applied to the rapid and simple determination of Cr(III) ion in the real samples. There is a good agreement between methods and atomic absorption spectrometry. The Beers law is obeyed over the concentration range of 0.1-13.7 μg mL-1 for micellar media. The detection limit is 0.8 ng mL-1. The molar absorptivity of complex is 5350 L mol-1 cm-1.

A flow method based on solvent extraction coupled on-line to a reversed micellar mediated chemiluminescence detection for selective determination of gold(III) and gallium(III) in water and industrial samples.

PubMed

Hasanin, Tamer H A; Okamoto, Yasuaki; Fujiwara, Terufumi

2016-02-01

A rapid and sensitive flow method, based on the combination of on-line solvent extraction with reversed micellar mediated chemiluminescence (CL) detection using rhodamine B (RB), was investigated for the selective determination of Au(III) and Ga(III) in aqueous solutions. 2.0 M HCl was the optimum for extracting Au(III) while a 5.0M HCl solution containing 2.5M LiCl was selected as an optimum acidic medium for extraction of Ga(III). The Au(III) and Ga(III) chloro-complex anions were extracted from the above aqueous acidic solutions into toluene as their ion-pair complexes with the protonated RBH(+) ion followed by membrane phase separation in a flow system. In a flow cell of a detector, the extract was mixed with the reversed micellar solution of cetyltrimethylammonium chloride (CTAC) in 1-hexanol-cyclohexane/water (1.0M HCl) containing 0.10 M cerium(IV) and 0.05 M lithium sulfate. Then uptake of the ion-pair by the CTAC reversed micelles and the subsequent CL oxidation of RB with Ce(IV) occurred easily and the CL signals produced were recorded. Using a flow injection system, a detection limit (DL) of 0.4 μM Au(III) and 0.6 μM Ga(III), and linear calibration graphs with dynamic ranges from the respective DLs to 10 μM for Au(III) and Ga(III) were obtained under the optimized experimental conditions. The relative standard deviations (n=6) obtained at 2.0 µM Au(III) and 4.0 µM Ga(III) were 3.0% and 2.4%, respectively. The presented CL methodology has been applied for the determination of Au(III) and Ga(III) in water and industrial samples with satisfactory results. Copyright © 2015 Elsevier B.V. All rights reserved.

Systematic theoretical investigation of the zero-field splitting in Gd(III) complexes: Wave function and density functional approaches

NASA Astrophysics Data System (ADS)

Khan, Shehryar; Kubica-Misztal, Aleksandra; Kruk, Danuta; Kowalewski, Jozef; Odelius, Michael

2015-01-01

The zero-field splitting (ZFS) of the electronic ground state in paramagnetic ions is a sensitive probe of the variations in the electronic and molecular structure with an impact on fields ranging from fundamental physical chemistry to medical applications. A detailed analysis of the ZFS in a series of symmetric Gd(III) complexes is presented in order to establish the applicability and accuracy of computational methods using multiconfigurational complete-active-space self-consistent field wave functions and of density functional theory calculations. The various computational schemes are then applied to larger complexes Gd(III)DOTA(H2O)-, Gd(III)DTPA(H2O)2-, and Gd(III)(H2O)83+ in order to analyze how the theoretical results compare to experimentally derived parameters. In contrast to approximations based on density functional theory, the multiconfigurational methods produce results for the ZFS of Gd(III) complexes on the correct order of magnitude.

Quantitation of heparosan with heparin lyase III and spectrophotometry.

PubMed

Huang, Haichan; Zhao, Yingying; Lv, Shencong; Zhong, Weihong; Zhang, Fuming; Linhardt, Robert J

2014-02-15

Heparosan is Escherichia coli K5 capsule polysaccharide, which is the key precursor for preparing bioengineered heparin. A rapid and effective quantitative method for detecting heparosan is important in the large-scale production of heparosan. Heparin lyase III (Hep III) effectively catalyzes the heparosan depolymerization, forming unsaturated disaccharides that are measurable using a spectrophotometer at 232 nm. We report a new method for the quantitative detection of heparosan with heparin lyase III and spectrophotometry that is safer and more specific than the traditional carbazole assay. In an optimized detection system, heparosan at a minimum concentration of 0.60 g/L in fermentation broth can be detected. Copyright © 2013 Elsevier Inc. All rights reserved.

Methods for determining soluble and insoluble Cr III and Cr VI compounds in welding fumes.

PubMed

Matczak, W; Chmielnicka, J

1989-01-01

An analytical procedure for simultaneous determination of soluble and insoluble Cr III and Cr VI compounds in welding fumes has been proposed. In the welding fume samples collected on a membrane filter, total chromium was determined with atomic absorption spectrophotometry (AAS). Glass filters with collected samples were divided into two parts. In one part of the sample, soluble and insoluble chromium was determined by means of AAS. The separation of soluble chromium III and VI was carried out on diphenylcarbazide resin. In the second part of the sample total chromium VI was determined by means of the colorimetric method with s-diphenylcarbazide. The difference in the results of these determinations allowed the calculation of the content of total Cr III, Cr III insolub. and Cr VI insolub. The results of determining chromium compounds in welding fumes samples collected in the welder's breathing zone and in experimental chambers are also presented in this paper. The content of total chromium in the fumes determined by AAS (from a membrane filtr) and that calculated from the sum of soluble and insoluble chromium (from a glass filter) were concordant and within the limits of the admissible error for the method. Total chromium content in welding fume samples collected individually was found to range from 2.4-4.2%. The percentage of particular chromium compounds as compared to total chromium (100%) amounted: total Cr III--34%, total Cr VI--66%, soluble chromium--66% and in this Cr III--20% and Cr VI--43%, insoluble chromium--34% and in this: Cr III--14% and Cr VI--20%.

Anodic Stripping Voltammetry with Pencil Graphite Electrode for Determination of Chromium (III)

NASA Astrophysics Data System (ADS)

Wyantuti, S.; Hafidza, R. A.; Ishmayana, S.; Hartati, Y. W.

2017-02-01

Chromium is required as micronutrient that has roles in insulin metabolism and blood glucose level regulation. Chromium (III) deficiency can cause hyperglycemia and glycosuria. However, a high amount of chromium in body can cause allergic reaction, organ damage, and even death because of its toxicity. Chromium is commonly used in steel industries. Simultaneously with the development of industry, the waste disposal that can endanger environment also increased. Therefore, a sensitive and specific analysis method for chromium detection is required. Stripping voltammetry is one of the voltammetric methods that is commonly used for heavy metal analysis due to the very low limit of detection (sub ppb). The present study was conducted to develop an analysis method for chromium (III) determination using pencil graphite electrode. Quantitative determination was performed for chromium (III) which measured at -0.8 to +1.0 V with deposition time for 60 s and 50 mV/s scan rate. Stripping voltammetric analysis of chromium (III) using pencil graphite electrode gave linear range at 12.5 to 75 ppm with limit of detection of 0.31 ppm.

Specific PCR primers directed to identify cryI and cryIII genes within a Bacillus thuringiensis strain collection.

PubMed Central

Cerón, J; Ortíz, A; Quintero, R; Güereca, L; Bravo, A

1995-01-01

In this paper we describe a PCR strategy that can be used to rapidly identify Bacillus thuringiensis strains that harbor any of the known cryI or cryIII genes. Four general PCR primers which amplify DNA fragments from the known cryI or cryIII genes were selected from conserved regions. Once a strain was identified as an organism that contains a particular type of cry gene, it could be easily characterized by performing additional PCR with specific cryI and cryIII primers selected from variable regions. The method described in this paper can be used to identify the 10 different cryI genes and the five different cryIII genes. One feature of this screening method is that each cry gene is expected to produce a PCR product having a precise molecular weight. The genes which produce PCR products having different sizes probably represent strains that harbor a potentially novel cry gene. Finally, we present evidence that novel crystal genes can be identified by the method described in this paper. PMID:8526493

Aircraft evacuations through type-III exits I : effects of seat placement at the exit.

DOT National Transportation Integrated Search

1995-07-01

Simulated emergency egress from Type III over-wing exits was studied to support regulatory action by the FAA. Passageway width and seat encroachment distance adjacent to the Type-III exit were the major variables of interest. : Methods. Two subject g...

Postoperative surgical complications of lymphadenohysterocolpectomy

PubMed Central

Marin, F; Pleşca, M; Bordea, CI; Voinea, SC; Burlănescu, I; Ichim, E; Jianu, CG; Nicolăescu, RR; Teodosie, MP; Maher, K; Blidaru, A

2014-01-01

Rationale The current standard surgical treatment for the cervix and uterine cancer is the radical hysterectomy (lymphadenohysterocolpectomy). This has the risk of intraoperative accidents and postoperative associated morbidity. Objective The purpose of this article is the evaluation and quantification of the associated complications in comparison to the postoperative morbidity which resulted after different types of radical hysterectomy. Methods and results Patients were divided according to the type of surgery performed as follows: for cervical cancer – group A- 37 classic radical hysterectomies Class III Piver - Rutledge -Smith ( PRS ), group B -208 modified radical hysterectomies Class II PRS and for uterine cancer- group C -79 extended hysterectomies with pelvic lymphadenectomy from which 17 patients with paraaortic lymphnode biopsy . All patients performed preoperative radiotherapy and 88 of them associated radiosensitization. Discussion Early complications were intra-abdominal bleeding ( 2.7% Class III PRS vs 0.48% Class II PRS), supra-aponeurotic hematoma ( 5.4% III vs 2.4% II) , dynamic ileus (2.7% III vs 0.96% II) and uro - genital fistulas (5.4% III vs 0.96% II).The late complications were the bladder dysfunction (21.6% III vs 16.35% II) , lower limb lymphedema (13.5% III vs 11.5% II), urethral strictures (10.8% III vs 4.8% II) , incisional hernias ( 8.1% III vs 7.2% II), persistent pelvic pain (18.91% III vs 7.7% II), bowel obstruction (5.4% III vs 1.4% II) and deterioration of sexual function (83.3% III vs 53.8% II). PRS class II radical hysterectomy is associated with fewer complications than PRS class III radical hysterectomy , except for the complications of lymphadenectomy . A new method that might reduce these complications is a selective lymphadenectomy represented by sentinel node biopsy . In conclusion PRS class II radical hysterectomy associated with neoadjuvant radiotherapy is a therapeutic option for the incipient stages of cervical cancer. Abbreviations: PRS- Piver Rutledge-Smith, II- class II, III- class III PMID:24653760

Voltammetric determination of arsenic in high iron and manganese groundwaters.

PubMed

Gibbon-Walsh, Kristoff; Salaün, Pascal; Uroic, M Kalle; Feldmann, Joerg; McArthur, John M; van den Berg, Constant M G

2011-09-15

Determination of the speciation of arsenic in groundwaters, using cathodic stripping voltammetry (CSV), is severely hampered by high levels of iron and manganese. Experiments showed that the interference is eliminated by addition of EDTA, making it possible to determine the arsenic speciation on-site by CSV. This work presents the CSV method to determine As(III) in high-iron or -manganese groundwaters in the field with only minor sample treatment. The method was field-tested in West-Bengal (India) on a series of groundwater samples. Total arsenic was subsequently determined after acidification to pH 1 by anodic stripping voltammetry (ASV). Comparative measurements by ICP-MS as reference method for total As, and by HPLC for its speciation, were used to corroborate the field data in stored samples. Most of the arsenic (78±0.02%) was found to occur as inorganic As(III) in the freshly collected waters, in accordance with previous studies. The data shows that the modified on-site CSV method for As(III) is a good measure of water contamination with As. The EDTA was also found to be effective in stabilising the arsenic speciation for longterm sample storage at room temperature. Without sample preservation, in water exposed to air and sunlight, the As(III) was found to become oxidised to As(V), and Fe(II) oxidised to Fe(III), removing the As(V) by adsorption on precipitating Fe(III)-hydroxides within a few hours. Copyright © 2011 Elsevier B.V. All rights reserved.

Assessment of the Asian Neurogastroenterology and Motility Association Chronic Constipation Criteria: An Asian Multicenter Cross-sectional Study

PubMed Central

Gwee, Kok-Ann; Bergmans, Paul; Kim, JinYong; Coudsy, Bogdana; Sim, Angelia; Chen, Minhu; Lin, Lin; Hou, Xiaohua; Wang, Huahong; Goh, Khean-Lee; Pangilinan, John A; Kim, Nayoung; des Varannes, Stanislas Bruley

2017-01-01

Background/Aims There is a need for a simple and practical tool adapted for the diagnosis of chronic constipation (CC) in the Asian population. This study compared the Asian Neurogastroenterology and Motility Association (ANMA) CC tool and Rome III criteria for the diagnosis of CC in Asian subjects. Methods This multicenter, cross-sectional study included subjects presenting at outpatient gastrointestinal clinics across Asia. Subjects with CC alert symptoms completed a combination Diagnosis Questionnaire to obtain a diagnosis based on 4 different diagnostic methods: self-defined, investigator’s judgment, ANMA CC tool, and Rome III criteria. The primary endpoint was the level of agreement/disagreement between the ANMA CC diagnostic tool and Rome III criteria for the diagnosis of CC. Results The primary analysis comprised of 449 subjects, 414 of whom had a positive diagnosis according to the ANMA CC tool. Rome III positive/ANMA positive and Rome III negative/ANMA negative diagnoses were reported in 76.8% and 7.8% of subjects, respectively, resulting in an overall percentage agreement of 84.6% between the 2 diagnostic methods. The overall percentage disagreement between these 2 diagnostic methods was 15.4%. A higher level of agreement was seen between the ANMA CC tool and self-defined (374 subjects [90.3%]) or investigator’s judgment criteria (388 subjects [93.7%]) compared with the Rome III criteria. Conclusion This study demonstrates that the ANMA CC tool can be a useful for Asian patients with CC. PMID:27764907

Simultaneous analysis of Cr(III), Cr(VI), and chromium picolinate in foods using capillary electrophoresis-inductively coupled plasma mass spectrometry.

PubMed

Chen, YiQuan; Chen, JinFa; Xi, Zhiming; Yang, Guidi; Wu, Zujian; Li, JianRong; Fu, FengFu

2015-05-01

We herein reported a method for the simultaneous detection of trace Cr(VI), Cr(III), and chromium(III) picolinate (CrPic) in foods using CE-ICP-MS together with ultrasonic-assisted extraction. The Cr(III) (Cr(3+) ) was chelated with trans-1,2-diaminocyclohexane-N,N,N´,N´-tetraacetic acid (DCTA) to form a single charged Cr-DCTA(-) complex. Then, Cr(VI) (CrO4 (2-) ), Cr-DCTA(-) , and CrPic were separated by CE within 8 min under a separation voltage of -13 KV followed by their monitoring with ICP mass spectrometer (ICP-MS). The proposed method is simple, effective, and sensitive. It has an instrument detection limit of 0.10, 0.18, and 0.20 ngCr/mL for Cr(VI), Cr(III), and CrPic, respectively. With the help of the methods, we have successfully determined Cr(VI), Cr(III), and CrPic in nutritional supplement (CrPic yeast tablet) with an RSD (n = 5) <6% and a recovery of 93-103%. The experimental results showed that CrPic was the main speciation of chromium in the nutritional supplement, with a concentration of 1514.6 μg Cr/g. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Magnetic Nature of the CrIII-LnIII Interactions in [CrIII2LnIII3] Clusters with Slow Magnetic Relaxation.

PubMed

Zhao, Xiao-Qing; Xiang, Shuo; Wang, Jin; Bao, Dong-Xu; Li, Yun-Chun

2018-02-01

Two 3 d -4 f hetero-metal pentanuclear complexes with the formula {[Cr III 2 Ln III 3 L 10 (OH) 6 (H 2 O) 2 ]Et 3 NH} [Ln=Tb ( 1 ), Dy ( 2 ); HL=pivalic acid, Et 3 N=triethylamine] have been produced. The metal core of each cluster is made up of a trigonal bipyramid with three Ln III ions (plane) and two Cr III ions (above and below) held together by six μ 3 -OH bridges. Also reported with this series is the diamagnetic Cr III -Y III analogue ( 3 ). Fortunately, we successfully prepared Al III -Ln III analogues with the formula {[Al III 2 Ln III 3 L 10 (OH) 6 (H 2 O) 2 ]Et 3 NH⋅H 2 O} [Ln=Tb ( 4 ), Dy ( 5 )], containing diamagnetic Al III ions, which can be used to evaluate the Cr III -Ln III magnetic nature through a diamagnetic substitution method. Subsequently, static (dc) magnetic susceptibility studies reveal dominant ferromagnetic interactions between Cr III and Ln III ions. Dynamic (ac) magnetic susceptibility studies show frequency-dependent out-of-phase ( χ '') signals for [Cr III 2 Tb III 3 ] ( 1 ), [Cr III 2 Dy III 3 ] ( 2 ), and [Al III 2 Dy III 3 ] ( 5 ), which are derived from the single-ion behavior of Ln III ions and/or the Cr III -Ln III ferromagnetic interactions.

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

Schrock, Richard Royce; Autenrieth, Benjamin

The present invention, among other things, provides highly syndiotactic poly(dicyclopentadiene) and/or hydrogenated poly(dicyclopentadiene), compositions thereof, and compounds and methods for preparing the same. In some embodiments, a provided compound is a compound of formula I, II or III. In some embodiments, a provided method comprises providing a compound of formula I, II or III.

Spectroscopic characterization and reactivity studies of a mononuclear nonheme Mn(III)-hydroperoxo complex.

PubMed

So, Hee; Park, Young Jun; Cho, Kyung-Bin; Lee, Yong-Min; Seo, Mi Sook; Cho, Jaeheung; Sarangi, Ritimukta; Nam, Wonwoo

2014-09-03

We report the first example of a mononuclear nonheme manganese(III)-hydroperoxo complex derived from protonation of an isolated manganese(III)-peroxo complex bearing an N-tetramethylated cyclam (TMC) ligand, [Mn(III)(TMC)(OOH)](2+). The Mn(III)-hydroperoxo intermediate is characterized with various spectroscopic methods as well as with density functional theory (DFT) calculations, showing the binding of a hydroperoxide ligand in an end-on fashion. The Mn(III)-hydroperoxo species is a competent oxidant in oxygen atom transfer (OAT) reactions, such as the oxidation of sulfides. The electrophilic character of the Mn(III)-hydroperoxo complex is demonstrated unambiguously in the sulfoxidation of para-substituted thioanisoles.

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

PubMed

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

2013-11-15

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

Separation and flame atomic absorption spectrometric determination of total chromium and chromium (III) in phosphate rock used for production of fertilizer.

PubMed

El-Sheikh, Amjad H; Al-Degs, Yahya S; Sweileh, Jamal A; Said, Adi J

2013-11-15

Due to the commercial value of phosphate rock (PR) as a fertilizer precursor, it is necessary to investigate its heavy metals content. Chromium (Cr) may present as Cr(III) or Cr(VI) in PR; but quantitative differentiation between them is not an easy task. This is due to possible interconversion of Cr species during the digestion/leaching process. In this work, ultrasound digestion (USD) of PR was optimized (300 mg PR, 4.0 mL of 4.0 mol L(-1) nitric acid, 15 min sonication) for the sake of leaching Cr species prior to their determination by flame atomic absorption spectroscopy. Using multi-walled carbon nanotube (MWCNT) as adsorbent, solid phase extraction (SPE) was used to separate Cr(III) from the digestate at pH 9, while total Cr was estimated after reducing Cr(VI) into Cr(III). The optimum USD/SPE method gave LOQ and LOD of Cr(III) of 0.96 mg kg(-1) and 0.288 mg kg(-1), respectively. The method sensitivity was 1.44×10(-3) AU kg mg(-1) within the studied Cr concentration range (5-400 mg kg(-1)). The USD/SPE method was validated by analyzing lake sediments LKSD-4 certified reference material, and by comparison with classical digestion method (CD). Application of USD/SPE on Jordanian PR samples gave total Cr rang 29.1-122.0 mg kg(-1) (±1.4-6.3), while Cr(III) ranged between 23.8 and 101.7 mg kg(-1) (±1.3-5.5). AFPC Rock Check Program samples gave total Cr range 238.9-394.7 mg kg(-1) (±11.5-24.1), while Cr(III) ranged between 202.4 and 335.8 mg kg(-1) (±11.4-18.3). These results were very close to the results obtained by the CD method. Copyright © 2013 Elsevier B.V. All rights reserved.

A newly validated and characterized spectrophotometric method for determination of a three water pollutants metal ions

NASA Astrophysics Data System (ADS)

Mohamed, Marwa E.; Frag, Eman Y. Z.; Mohamed, Mona A.

2018-01-01

A simple, fast and accurate spectrophotometric method had been developed to determine lead (II), chromium (III) and barium (II) ions in pure forms and in spiked water samples using thoron (THO) as a reagent forming colored complexes. It was found that the formed complexes absorbed maximally at 539, 540 and 538 nm for Pb(II)-THO, Cr(III)-THO and Ba(II)-THO complexes, respectively. The optimum experimental conditions for these complexes had been studied carefully. Beer's law was obeyed in the range 1-35, 1-70, and 1-45 μg mL- 1 for Pb (II), Cr(III) and Ba(II) ions with THO reagent, respectively. Different parameters such as linearity, selectivity, recovery, limits of quantification and detection, precision and accuracy were also evaluated in order to validate the proposed method. The results showed that, THO was effective in simultaneous determination of Pb(II), Cr(III) and Ba(III) ions in pure forms and in spiked water samples. Also, the results of the proposed method were compared with that obtained from atomic absorption spectrometry. The isolated solid complexes had been characterized using elemental analysis, X-ray powder diffraction (XRD), IR, mass spectrometry and TD-DFT calculations. Their biological activities were investigated against different types of bacteria and fungi organisms.

A detection method in living plant cells for rapidly monitoring the response of plants to exogenous lanthanum.

PubMed

Cheng, Mengzhu; Wang, Lihong; Yang, Qing; Huang, Xiaohua

2018-08-30

The pollution of rare earth elements (REEs) in ecosystem is becoming more and more serious, so it is urgent to establish methods for monitoring the pollution of REEs. Monitoring environmental pollution via the response of plants to pollutants has become the most stable and accurate method compared with traditional methods, but scientists still need to find the primary response of plants to pollutants to improve the sensitivity and speed of this method. Based on the facts that the initiation of endocytosis is the primary cellular response of the plant leaf cells to REEs and the detection of endocytosis is complex and expensive, we constructed a detection method in living plant cells for rapidly monitoring the response of plants to exogenous lanthanum [La(III), a representative of REEs] by designing a new immuno-electrochemical method for detecting the content change in extracellular vitronectin-like protein (VN) that are closely related to endocytosis. Results showed that when 30 μM La(III) initiated a small amount of endocytosis, the content of extracellular VN increased by 5.46 times, but the structure and function of plasma membrane were not interfered by La(III); when 80 μM La(III) strongly initiated a large amount of endocytosis, the content of extracellular VN increased by 119 times, meanwhile, the structure and function of plasma membrane were damaged. In summary, the detection method can reflect the response of plants to La(III) via detecting the content change in extracellular VN, which provides an effective and convenient way to monitor the response of plants to exogenous REEs. Copyright © 2018. Published by Elsevier Inc.

A new cation-exchange method for accurate field speciation of hexavalent chromium

USGS Publications Warehouse

Ball, J.W.; McCleskey, R. Blaine

2003-01-01

A new method for field speciation of Cr(VI) has been developed to meet present stringent regulatory standards and to overcome the limitations of existing methods. The method consists of passing a water sample through strong acid cation-exchange resin at the field site, where Cr(III) is retained while Cr(VI) passes into the effluent and is preserved for later determination. The method is simple, rapid, portable, and accurate, and makes use of readily available, inexpensive materials. Cr(VI) concentrations are determined later in the laboratory using any elemental analysis instrument sufficiently sensitive to measure the Cr(VI) concentrations of interest. The new method allows measurement of Cr(VI) concentrations as low as 0.05 ??g 1-1, storage of samples for at least several weeks prior to analysis, and use of readily available analytical instrumentation. Cr(VI) can be separated from Cr(III) between pH 2 and 11 at Cr(III)/Cr(VI) concentration ratios as high as 1000. The new method has demonstrated excellent comparability with two commonly used methods, the Hach Company direct colorimetric method and USEPA method 218.6. The new method is superior to the Hach direct colorimetric method owing to its relative sensitivity and simplicity. The new method is superior to USEPA method 218.6 in the presence of Fe(II) concentrations up to 1 mg 1-1 and Fe(III) concentrations up to 10 mg 1-1. Time stability of preserved samples is a significant advantage over the 24-h time constraint specified for USEPA method 218.6.

Prediction of trivalent actinide amino(poly)carboxylate complex stability constants using linear free energy relationships with the lanthanide series

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

Uhnak, Nic E.

Prediction of Trivalent Actinide Amino(poly)carboxylate Complex Stability Constants Using Linear Free Energy Relationships with the Lanthanide Series Alternative title: LFER Based Prediction of An(III) APC Stability Constants There is a gap in the literature regarding the complexation of amino(poly)carboxylate (APC) ligands with trivalent actinides (An(III))). The chemistry of the An(III) is nearly identical to that of the trivalent lanthanides Lns, but the An(III) express a slight enhancement when binding APC ligands. Presented in this report is a simple method of predicting the stability constants of the An(III), Pu, Am, Cm, Bk and Cf by using linear free energy relationships (LFER)more » of the An and the lanthanide (Ln) series for 91 APCs. This method produced An stability constants within uncertainty to available literature values for most ligands.« less

Acetylcholinesterase inhibition-based biosensor for aluminum(III) chronoamperometric determination in aqueous media.

PubMed

Barquero-Quirós, Miriam; Domínguez-Renedo, Olga; Alonso-Lomillo, Maria Asunción; Arcos-Martínez, María Julia

2014-05-07

A novel amperometric biosensor for the determination of Al(III) based on the inhibition of the enzyme acetylcholinesterase has been developed. The immobilization of the enzyme was performed on screen-printed carbon electrodes modified with gold nanoparticles. The oxidation signal of acetylthiocholine iodide enzyme substrate was affected by the presence of Al(III) ions leading to a decrease in the amperometric current. The developed system has a detection limit of 2.1 ± 0.1 μM for Al(III). The reproducibility of the method is 8.1% (n = 4). Main interferences include Mo(VI), W(VI) and Hg(II) ions. The developed method was successfully applied to the determination of Al(III) in spiked tap water . The analysis of a certified standard reference material was also carried out. Both results agree with the certified values considering the respective associated uncertainties.

Acetylcholinesterase Inhibition-Based Biosensor for Aluminum(III) Chronoamperometric Determination in Aqueous Media

PubMed Central

Barquero-Quirós, Miriam; Domínguez-Renedo, Olga; Alonso-Lomillo, Maria Asunción; Arcos-Martínez, María Julia

2014-01-01

A novel amperometric biosensor for the determination of Al(III) based on the inhibition of the enzyme acetylcholinesterase has been developed. The immobilization of the enzyme was performed on screen-printed carbon electrodes modified with gold nanoparticles. The oxidation signal of acetylthiocholine iodide enzyme substrate was affected by the presence of Al(III) ions leading to a decrease in the amperometric current. The developed system has a detection limit of 2.1 ± 0.1 μM for Al(III). The reproducibility of the method is 8.1% (n = 4). Main interferences include Mo(VI), W(VI) and Hg(II) ions. The developed method was successfully applied to the determination of Al(III) in spiked tap water. The analysis of a certified standard reference material was also carried out. Both results agree with the certified values considering the respective associated uncertainties. PMID:24811076

Extrapyramidal Symptoms and Medication Use in Mucopolysaccharidosis Type III

ERIC Educational Resources Information Center

Tchan, Michel C.; Sillence, David

2009-01-01

Background: We report the case of a 16-year-old male with Mucopolysaccharidosis III type A (Sanfilippo syndrome) who was commenced on risperidone for behaviour management. He rapidly developed extrapyramidal symptoms that have not resolved. Method: The medication histories of 20 patients with Mucopolysaccharidosis III seen at a Lysosomal Storage…

An Experiment on Isomerism in Metal-Amino Acid Complexes.

ERIC Educational Resources Information Center

Harrison, R. Graeme; Nolan, Kevin B.

1982-01-01

Background information, laboratory procedures, and discussion of results are provided for syntheses of cobalt (III) complexes, I-III, illustrating three possible bonding modes of glycine to a metal ion (the complex cations II and III being linkage/geometric isomers). Includes spectrophotometric and potentiometric methods to distinguish among the…

Method of fabricating vertically aligned group III-V nanowires

DOEpatents

Wang, George T; Li, Qiming

2014-11-25

A top-down method of fabricating vertically aligned Group III-V micro- and nanowires uses a two-step etch process that adds a selective anisotropic wet etch after an initial plasma etch to remove the dry etch damage while enabling micro/nanowires with straight and smooth faceted sidewalls and controllable diameters independent of pitch. The method enables the fabrication of nanowire lasers, LEDs, and solar cells.

Vertical group III-V nanowires on si, heterostructures, flexible arrays and fabrication

DOEpatents

Wang, Deli; Soci, Cesare; Bao, Xinyu; Wei, Wei; Jing, Yi; Sun, Ke

2015-01-13

Embodiments of the invention provide a method for direct heteroepitaxial growth of vertical III-V semiconductor nanowires on a silicon substrate. The silicon substrate is etched to substantially completely remove native oxide. It is promptly placed in a reaction chamber. The substrate is heated and maintained at a growth temperature. Group III-V precursors are flowed for a growth time. Preferred embodiment vertical Group III-V nanowires on silicon have a core-shell structure, which provides a radial homojunction or heterojunction. A doped nanowire core is surrounded by a shell with complementary doping. Such can provide high optical absorption due to the long optical path in the axial direction of the vertical nanowires, while reducing considerably the distance over which carriers must diffuse before being collected in the radial direction. Alloy composition can also be varied. Radial and axial homojunctions and heterojunctions can be realized. Embodiments provide for flexible Group III-V nanowire structures. An array of Group III-V nanowire structures is embedded in polymer. A fabrication method forms the vertical nanowires on a substrate, e.g., a silicon substrate. Preferably, the nanowires are formed by the preferred methods for fabrication of Group III-V nanowires on silicon. Devices can be formed with core/shell and core/multi-shell nanowires and the devices are released from the substrate upon which the nanowires were formed to create a flexible structure that includes an array of vertical nanowires embedded in polymer.

Complexation of Curium(III) with DTPA at 10–70 °C: Comparison with Eu(III)–DTPA in Thermodynamics, Luminescence, and Coordination Modes

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

Tian, Guoxin; Zhang, Zhiyong; Martin, Leigh R.

Separation of trivalent actinides (An(III)) from trivalent lanthanides (Ln(III)) is a challenging task because of their nearly identical chemical properties. Diethylenetriaminepentaacetate (DTPA), a key reagent used in the TALSPEAK process that effectively separates An(III) from Ln(III), is believed to play a critical role in the An(III)/Ln(III) separation. However, the underlying principles for the separation based on the difference in the complexation of DTPA with An(III) and Ln(III) remain unclear. In this work, the complexation of DTPA with Cm(III) at 10-70 ºC was investigated by spectrophotometry, luminescence spectroscopy, and microcalorimetry, in conjunction with computational methods. The binding strength, the enthalpy ofmore » complexation, the coordination modes, and the luminescence properties are compared between the Cm(III)-DTPA and Eu(III)-DTPA systems. The experimental and computational data have demonstrated that the difference between Cm(III) and Eu(III) in the binding strength with DTPA can be attributed to the stronger covalence bonding between Cm(III) and the nitrogen donors of DTPA.« less

Crystal growth methods dedicated to low solubility actinide oxalates

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

Tamain, C., E-mail: christelle.tamain@cea.fr; Arab-Chapelet, B.; Rivenet, M.

Two novel crystal growth syntheses dedicated to low solubility actinide-oxalate systems and adapted to glove box handling are described. These methods based on the use of precursors of either actinide metal or oxalic acid have been optimized on lanthanide systems (analogue of actinides(III)) and then assessed on real actinide systems. They allow the synthesis of several actinide oxalate single crystals, Am{sub 2}(C{sub 2}O{sub 4}){sub 3}(H{sub 2}O){sub 3}·xH{sub 2}O, Th(C{sub 2}O{sub 4}){sub 2}·6H{sub 2}O, M{sub 2+x}[Pu{sup IV}{sub 2−x}Pu{sup III}{sub x}(C{sub 2}O{sub 4}){sub 5}]·nH{sub 2}O and M{sub 1−x}[Pu{sup III}{sub 1−x}Pu{sup IV}{sub x}(C{sub 2}O{sub 4}){sub 2}·H{sub 2}O]·nH{sub 2}O. It is the first timemore » that these well-known compounds are formed by crystal growth methods, thus enabling direct structural studies on transuranic element systems and acquisition of basic data beyond deductions from isomorphic (or not) lanthanide compounds. Characterizations by X-ray diffraction, UV–visible solid spectroscopy, demonstrate the potentialities of these two crystal growth methods to obtain oxalate compounds. - Graphical abstract: Two new single crystal growth methods dedicated to actinide oxalate compounds. - Highlights: • Use of diester as oxalate precursor for crystal growth of actinide oxalates. • Use of actinide oxide as precursor for crystal growth of actinide oxalates. • Crystal growth of Pu(III) and Am(III) oxalates. • Crystal growth of mixed Pu(III)/Pu(IV) oxalates.« less

Method for the determination of chromium in feed matrix by HPLC.

PubMed

Umesh, Balakrishnan; Rajendran, Rajendra Moorthy; Manoharan, Muthu Tamizh

2015-11-01

An improved method for the chromatographic separation and determination of chromium (III) and (VI) [ CRIII AND CRVI: ] in mineral mixtures and feed samples has been developed. The method uses precolumn derivatization using ammonium pyrrolidinedithiocarbamate ( APD: ) followed by reversed-phase liquid chromatography to separate the chromium ions. Both Cr(III) and Cr(VI) species are chelated with ammonium pyrrolidinedithiocarbamate prior to separation by mixing with acetonitrile and 0.5 mmol acetate buffer (pH 4.5). Optimum chromatographic separations were obtained with a polymer-based reversed-phase column (Kinetex, 5 μ, 250 × 4.5 mm, Phenomenex, Torrance, CA) and a mobile phase containing acetonitrile and water (7:3). Both Cr(III) and Cr(VI) ion concentrations were directly determined from the corresponding areas in the chromatogram. The effect of analytical parameters, including pH, concentration of ligand, incubation temperature, and mobile phase, was optimized for both chromium complexes. The range of the procedure was found to be linear for Cr(III) and Cr(VI) concentrations between 0.125 and 4 μg/mL (r² = 0.9926) and 0.1 and 3.0 μg/mL (r² = 0.9983), respectively. Precision was evaluated by replicate analysis in which the percentage relative standard deviation values for chromium complex were found to be below 4.0. The recoveries obtained (85-115%) for both Cr(III) and Cr(VI) complexes indicated the accuracy of the developed method. The degradation products, as well as the excipients, were well resolved from the chromium complex peak in the chromatogram. Finally, the new method proved to be suitable for routine analysis of Cr(III) and Cr(VI) species in raw materials, mineral mixtures, and feed samples. © 2015 Poultry Science Association Inc.

Method and apparatus for use of III-nitride wide bandgap semiconductors in optical communications

DOEpatents

Hui, Rongqing [Lenexa, KS; Jiang, Hong-Xing [Manhattan, KS; Lin, Jing-Yu [Manhattan, KS

2008-03-18

The present disclosure relates to the use of III-nitride wide bandgap semiconductor materials for optical communications. In one embodiment, an optical device includes an optical waveguide device fabricated using a III-nitride semiconductor material. The III-nitride semiconductor material provides for an electrically controllable refractive index. The optical waveguide device provides for high speed optical communications in an infrared wavelength region. In one embodiment, an optical amplifier is provided using optical coatings at the facet ends of a waveguide formed of erbium-doped III-nitride semiconductor materials.

Is it photosensitization or photodegradation when UV-B irradiation is combined with BDE-47? Evidence from the growth and reproduction changes of rotifer Brachionus plicatilis.

PubMed

Liu, Chunchen; Tang, Xuexi; Zhou, Bin; Jiang, Yongshun; Lv, Mengchen; Zang, Yu; Wang, You

2018-07-01

Ecotoxicological methods were applied in the present study, and the marine rotifer Brachionus plicatilis was used as the toxic endpoint to depict what occurred when 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) was combined with solar ultraviolet-B radiation (UV-B). B. plicatilis was exposed to three different combination methods of BDE-47 and UV-B at an equal toxicity ratio, including normal rotifer co-cultured with UV-B-irradiated BDE-47 (known as Method I), UV-B-irradiated rotifer co-cultured with BDE-47 exposure (known as Method II) and normal rotifer co-cultured with the simultaneous addition of BDE-47 and UV-B irradiation (known as Method III). Acute and chronic experiments were preformed to determine the toxicity differentiation according to the growth and reproduction changes in the rotifer. Twenty-four-hour acute experiments showed that the modes of three combined methods changed from antagonism to additive, to synergistic with the concentration/dose increment, and the contribution rates of Method I and Method II to Method III were calculated by approximately 40.4% and 59.6%, respectively. Chronic exposure to either the single stressor or the combination of stressors inhibited the growth and reproduction of the rotifer, demonstrating the inhibition of the population growth rate and the decrease in the larvae production. Three combined groups presented more serious damages compared to groups with single stress exposure, and the ascending sequence of toxicity was Method I

[Affinity between CrIII and purified DNA, studied by competition with an intercalating agent: ethidium bromide].

PubMed

Vecchio, D; Balbi, C; Russo, P; Parodi, S; Santi, L

1981-05-30

The affinity between CrIII and purified calf- thymus DNA was studied at neutral pH by competition with ethidium bromide. Competition results indicated an affinity between CrIII and DNA of the order of 10(5) 1/mole. These results are in good agreement with previous results CrIII - DNA affinity was studied by the independent method of equilibrium dialysis and chromium dosage by atomic spectrometry.

Taxus ingredients in the red arils of Taxus baccata L. determined by HPLC-MS/MS.

PubMed

Siegle, Lydia; Pietsch, Jörg

2018-02-09

Taxus baccata L. is an evergreen conifer whose plant parts are cardiotoxic. Only the red arils of the berries are described as non-toxic and taxane-free. Extraction and HPLC-MS/MS methods were developed for the investigation of the Taxus compounds 3,5-dimethoxyphenol, 10-deacetylbaccatin III, baccatin III, cephalomannine, taxol A and taxinine M in the red arils of the yew berries. MethodologyA liquid-liquid extraction method for the red arils of the fruits from three yews were developed. An accurate (ESI+) HPLC-MS/MS method was performed for the simultaneous detection and determination of the target compounds in multiple reaction monitoring (MRM) mode. All Taxus agents obtained were detected in the red arils. Highest concentrations were determined for baccatin III and 10-deacetylbaccatin III. The developed quantitative method is reliable and selective and was successfully applied for quantification of selected Taxus ingredients in red arils of Taxus baccata. It was disproved that the red arils of the berries do not contain the selected Taxus compounds. Copyright © 2018 John Wiley & Sons, Ltd.

Investigation on the co-luminescence effect of europium (III)-lanthanum(III)-dopamine-sodium dodecylbenzene sulfonate system and its application.

PubMed

Si, Hailin; Zhao, Fang; Cai, Huan

2013-01-01

A novel luminescence, enhancement phenomenon in the europium(III)-dopamine-sodium dodecylbenzene sulfonate system was observed when lanthanum(III) was added. Based on this, a sensitive co-luminescence method was established for the determination of dopamine. The luminescence signal for the europium (III)-lanthanum(III)-dopamine-sodium dodecylbenzene sulfonate system was monitored at λ(ex) = 300 nm, λ(em) = 618 nm and pH 8.3. Under optimized conditions, the enhanced luminescence signal responded linearly to the concentration of dopamine in the range 1.0 × 10(-10)-5.0 × 10(-7) mol/L with a correlation coefficient of 0.9993 (n = 11). The detection limit (3σ) was 2.7 × 10(-11) mol/L and the relative standard deviation for 11 parallel measurements of 3.0 × 10(-8) mol/L dopamine was 1.9%. The presented method was successfully applied for the estimation of dopamine in samples of pharmaceutical preparations, human serum and urine. The possible luminescence enhancement mechanism of the system is discussed briefly. Copyright © 2013 John Wiley & Sons, Ltd.

Spectrophotometric study of the thorium-morin mixed-color system

USGS Publications Warehouse

Fletcher, M.H.; Milkey, R.G.

1956-01-01

A spectrophotometric study was made of the thoriummorin reaction to evaluate the suitability of morin as a reagent for the determination of trace amounts of thorium. At pH 2, the equilibrium constant for the reaction is 1 ?? 106, and a single complex having a thorium-morin ratio of 1 to 2 is formed. The complex shows maximum absorbance at a wave length of 410 m??, and its absorbance obeys Beer's law. The absorbance readings are highly reproducible, and the sensitivity is relatively high, an absorbance difference of 0.001 being equivalent to 0.007 ?? of ThO2 per sq. cm. The effects of acid, alcohol, and morin concentration, time, temperature, and age of the morin reagent as well as the behavior of morin with zirconium(IV), iron(III), aluminum(III), ytterbium(III), yttrium(III), uranium(VI), praseodymium(III), lead(II), lanthanum(III), and calcium(II) ions are discussed. A method is presented for the determination of thorium in pure solutions. Appropriate separations for the isolation of thorium may extend the usefulness of the method and permit the determination of trace amounts of thorium in complex materials.

Chimeric antigen receptor containing ICOS signaling domain mediates specific and efficient antitumor effect of T cells against EGFRvIII expressing glioma

PubMed Central

2013-01-01

Background Adoptive transfer of chimeric antigen receptor (CAR)-modified T cells appears to be a promising immunotherapeutic strategy. CAR combines the specificity of antibody and cytotoxicity of cytotoxic T lymphocytes, enhancing T cells’ ability to specifically target antigens and to effectively kill cancer cells. Recent efforts have been made to integrate the costimulatory signals in the CAR to improve the antitumor efficacy. Epidermal growth factor receptor variant III (EGFRvIII) is an attractive therapeutic target as it frequently expresses in glioma and many other types of cancers. Our current study aimed to investigate the specific and efficient antitumor effect of T cells modified with CAR containing inducible costimulator (ICOS) signaling domain. Methods A second generation of EGFRvIII/CAR was generated and it contained the EGFRvIII single chain variable fragment, ICOS signaling domain and CD3ζ chain. Lentiviral EGFRvIII/CAR was prepared and human CD3+ T cells were infected by lentivirus encoding EGFRvIII/CAR. The expression of EGFRvIII/CAR on CD3+ T cells was confirmed by flow cytometry and Western blot. The functions of EGFRvIII/CAR+ T cells were evaluated using in vitro and in vivo methods including cytotoxicity assay, cytokine release assay and xenograft tumor mouse model. Results Chimeric EGFRvIIIscFv-ICOS-CD3ζ (EGFRvIII/CAR) was constructed and lentiviral EGFRvIII/CAR were made to titer of 106 TU/ml. The transduction efficiency of lentiviral EGFRvIII/CAR on T cells reached around 70% and expression of EGFRvIII/CAR protein was verified by immunoblotting as a band of about 57 kDa. Four hour 51Cr release assays demonstrated specific and efficient cytotoxicity of EGFRvIII/CAR+ T cells against EGFRvIII expressing U87 cells. A robust increase in the IFN-γ secretion was detected in the co-culture supernatant of the EGFRvIII/CAR+ T cells and the EGFRvIII expressing U87 cells. Intravenous and intratumor injection of EGFRvIII/CAR+ T cells inhibited the in vivo growth of the EGFRvIII expressing glioma cells. Conclusions Our study demonstrates that the EGFRvIII/CAR-modified T cells can destroy glioma cells efficiently in an EGFRvIII specific manner and release IFN-γ in an antigen dependent manner. The specific recognition and effective killing activity of the EGFRvIII-directed T cells with ICOS signaling domain lays a foundation for us to employ such approach in future cancer treatment. PMID:23656794

Development of a highly sensitive and selective method for extractive spectrophotometric determination of aluminum(III) from environmental matrices, synthetic mixtures, and alloys using orthohydroxypropiophenoneisonicotinoylhydrazone.

PubMed

Ramachandraiah, C; Rajesh Kumar, J; Adinarayana Reddy, S; Lee, Jin-Young; Varada Reddy, A

2010-01-01

Orthohydroxypropiophenoneisonicotinoylhydrazone (OHPINH) is proposed as a new sensitive reagent for the spectrophotometric determination of aluminum(III). OHPINH formed a greenish-yellow colored complex with aluminum(III) in buffer solutions of pH 1 to 3. The color in pH 2 was stable for more than 48 h. The complex solution has given maximum absorbance at 390 nm when the reagent was chosen as blank and the absorbance of the reagent at this wavelength is negligible; the molar absorptivity and Sandell's sensitivity being 0.6371x10(4) L mol(-1) cm(-1) and 4.234x10(-3) microg cm(-2), respectively. The system obeys Beer's law in the range of 0.5-3.5 microg mL(-1) with excellent linearity in terms of the correlation coefficient value of 0.999. Most of the common metal ions generally found associated with aluminum(III) do not interfere. The repeatability of the method was checked by finding the relative standard deviation. The developed method has been successfully employed for the determination of aluminum(III) environmental matrices like medicinal and leafy samples, alloys, and synthetic mixtures.

Magnetic Nature of the CrIII–LnIII Interactions in [CrIII 2LnIII 3] Clusters with Slow Magnetic Relaxation

PubMed Central

Xiang, Shuo; Wang, Jin; Bao, Dong‐Xu; Li, Yun‐Chun

2018-01-01

Abstract Two 3d‐4f hetero‐metal pentanuclear complexes with the formula {[CrIII 2LnIII 3L10(OH)6(H2O)2]Et3NH} [Ln=Tb (1), Dy (2); HL=pivalic acid, Et3N=triethylamine] have been produced. The metal core of each cluster is made up of a trigonal bipyramid with three LnIII ions (plane) and two CrIII ions (above and below) held together by six μ 3‐OH bridges. Also reported with this series is the diamagnetic CrIII–YIII analogue (3). Fortunately, we successfully prepared AlIII–LnIII analogues with the formula {[AlIII 2LnIII 3L10(OH)6(H2O)2]Et3NH⋅H2O} [Ln=Tb (4), Dy (5)], containing diamagnetic AlIII ions, which can be used to evaluate the CrIII–LnIII magnetic nature through a diamagnetic substitution method. Subsequently, static (dc) magnetic susceptibility studies reveal dominant ferromagnetic interactions between CrIII and LnIII ions. Dynamic (ac) magnetic susceptibility studies show frequency‐dependent out‐of‐phase (χ′′) signals for [CrIII 2TbIII 3] (1), [CrIII 2DyIII 3] (2), and [AlIII 2DyIII 3] (5), which are derived from the single‐ion behavior of LnIII ions and/or the CrIII–LnIII ferromagnetic interactions. PMID:29435404

Physical characterization of the cloned protease III gene from Escherichia coli K-12.

PubMed

Dykstra, C C; Kushner, S R

1985-09-01

Analysis of the cloned protease III gene (ptr) from Escherichia coli K-12 has demonstrated that in addition to the previously characterized 110,000-Mr protease III protein, a second 50,000-Mr polypeptide (p50) is derived from the amino-terminal end of the coding sequence. The p50 polypeptide is found predominantly in the periplasmic space along with protease III, but does not proteolytically degrade insulin, a substrate for protease III. p50 does not appear to originate from autolysis of the larger protein. Protease III is not essential for normal cell growth since deletion of the structural gene causes no observed alterations in the phenotypic properties of the bacteria. A 30-fold overproduction of protease III does not affect cell viability. A simple new purification method for protease III is described.

A simple method for calculating growth rates of petroleum hydrocarbon plumes

USGS Publications Warehouse

Bekins, B.A.; Cozzarelli, I.M.; Curtis, G.P.

2005-01-01

Consumption of aquifer Fe(III) during biodegradation of ground water contaminants may result in expansion of a contaminant plume, changing the outlook for monitored natural attenuation. Data from two research sites contaminated with petroleum hydrocarbons show that toluene and xylenes degrade under methanogenic conditions, but the benzene and ethylbenzene plumes grow as aquifer Fe(III) supplies are depleted. By considering a one-dimensional reaction front in a constant unidirectional flow field, it is possible to derive a simple expression for the growth rate of a benzene plume. The method balances the mass flux of benzene with the Fe(III) content of the aquifer, assuming that the biodegradation reaction is instantaneous. The resulting expression shows that the benzene front migration is retarded relative to the ground water velocity by a factor that depends on the concentrations of hydrocarbon and bioavailable Fe(III). The method provides good agreement with benzene plumes at a crude oil study site in Minnesota and a gasoline site in South Carolina. Compared to the South Carolina site, the Minnesota site has 25% higher benzene flux but eight times the Fe(III), leading to about one-sixth the expansion rate. Although it was developed for benzene, toluene, ethylbenzene, and xylenes, the growth-rate estimation method may have applications to contaminant plumes from other persistent contaminant sources. Copyright ?? 2005 National Ground Water Association.

Usefulness of Wave Data Assimilation to the WAVE WATCH III Modeling System

NASA Astrophysics Data System (ADS)

Choi, J. K.; Dykes, J. D.; Yaremchuk, M.; Wittmann, P.

2017-12-01

In-situ and remote-sensed wave data are more abundant currently than in years past, with excellent accuracy at global scales. Forecast skill of the WAVE WATCH III model is improved by assimilation of these measurements and they are also useful for model validation and calibration. It has been known that the impact of assimilation in wind-sea conditions is not large, but spectra that result in large swell with long term propagation are identified and assimilated, the improved accuracy of the initial conditions improve the long-term forecasts. The Navy's assimilation method started with the simple Optimal Interpolation (OI) method. Operationally, Fleet Numerical Meteorology and Oceanography Center uses the sequential 2DVar scheme, but a new approach has been tested based on an adjoint-free method to variational assimilation in WAVE WATCH III. We will present the status of wave data assimilation into the WAVE WATCH III numerical model and upcoming development of this new adjoint-free variational approach.

Effect of alkali cations on two-dimensional networks of two new quaternary thioarsenates (III) prepared by a facile surfactant-thermal method

NASA Astrophysics Data System (ADS)

Yan, Dongming; Hou, Peipei; Liu, Chang; Chai, Wenxiang; Zheng, Xuerong; Zhang, Luodong; Zhi, Mingjia; Zhou, Chunmei; Liu, Yi

2016-09-01

Two new quaternary thioarsenates(III) NaAg2AsS3·H2O (1) and KAg2AsS3 (2) with high yields have been successfully prepared through a facile surfactant-thermal method. It is interesting that 2 can only be obtained with the aid of ethanediamine (en), which indicates that weak basicity of solvent is beneficial to the growth of 2 compared with 1. Both 1 and 2 feature the similar two-dimensional (2D) layer structures. However, the distortion of the primary honeycomb-like nets in 2 is more severe than that of 1, which demonstrates that Na+ and K+ cations have different structure directing effects on these two thioarsenates(III). Both experimental and theoretical studies confirm 1 and 2 are semiconductors with band gaps in the visible region. Our success in preparing these two quaternary thioarsenates(III) proves that surfactant-thermal technique is a powerful yet facile synthetic method to explore new complex chalcogenides.

Novel functionalized pyridine-containing DTPA-like ligand. Synthesis, computational studies and characterization of the corresponding Gd(III) complex.

PubMed

Artali, Roberto; Botta, Mauro; Cavallotti, Camilla; Giovenzana, Giovanni B; Palmisano, Giovanni; Sisti, Massimo

2007-08-07

A novel pyridine-containing DTPA-like ligand, carrying additional hydroxymethyl groups on the pyridine side-arms, was synthesized in 5 steps. The corresponding Gd(III) complex, potentially useful as an MRI contrast agent, was prepared and characterized in detail by relaxometric methods and its structure modeled by computational methods.

Research Ethics III: Publication Practices and Authorship, Conflicts of Interest, and Research Misconduct

ERIC Educational Resources Information Center

Horner, Jennifer; Minifie, Fred D.

2011-01-01

Purpose: In this series of articles--"Research Ethics I", "Research Ethics II", and "Research Ethics III"--the authors provide a comprehensive review of the 9 core domains for the responsible conduct of research (RCR) as articulated by the Office of Research Integrity. Method: In "Research Ethics III", they review the RCR domains of publication…

Methods for fabricating thin film III-V compound solar cell

DOEpatents

Pan, Noren; Hillier, Glen; Vu, Duy Phach; Tatavarti, Rao; Youtsey, Christopher; McCallum, David; Martin, Genevieve

2011-08-09

The present invention utilizes epitaxial lift-off in which a sacrificial layer is included in the epitaxial growth between the substrate and a thin film III-V compound solar cell. To provide support for the thin film III-V compound solar cell in absence of the substrate, a backing layer is applied to a surface of the thin film III-V compound solar cell before it is separated from the substrate. To separate the thin film III-V compound solar cell from the substrate, the sacrificial layer is removed as part of the epitaxial lift-off. Once the substrate is separated from the thin film III-V compound solar cell, the substrate may then be reused in the formation of another thin film III-V compound solar cell.

Diffusion of Eu(III) in compacted bentonite-effect of pH, solution concentration and humic acid.

PubMed

Wang, Xiangke; Chen, Yixue; Wu, Yican

2004-06-01

The effect of pH, Eu(III) solution concentration and humic acid on the diffusion of Eu(III) in compacted bentonite (rho(b) = 1000 +/- 30 kg/m(3)) was studied with "in-diffusion" method at an ionic strength of 0.1M NaClO(4). The results (K(d) values from the first slice and theoretical calculation, apparent and effective diffusion coefficients) derived from the new capillary method are in good agreement with the literature data under similar conditions, and fit the Fick's second law very well. The results suggest that the diffusion of Eu(III) is dependent on pH values and independent on solution concentration in our experimental conditions. Humic acid forms precipitation/complexation with Eu(III) at the surface of compacted bentonite and thus deduces the diffusion/transport of Eu(III) in compacted bentonite. The K(d) values in compacted bentonite are in most cases lower than those in powdered bentonite obtained from batch experiments. The difference between the K(d) values from powdered and compacted bentonite is a strong function of the bulk density of the bentonite. The results suggest that the content of interlaminary space plays a very important role to the diffusion, sorption and migration of Eu(III) in compacted bentonite.

Solid phase extraction of gold(III) on attapulgite modified with triocarbohydrazide prior to its determination in environmental samples by ICP-OES.

PubMed

Zhang, Li; Li, Zhenhua; Hu, Zheng; Chang, Xijun

2011-09-01

The first study on the high efficiency of triocarbohydrazide modified attapulgite as solid-phase extractant for preconcentration of trace Au(III) prior to the measurement by inductively coupled plasma optical emission spectrometry (ICP-OES) has been reported. Experimental conditions for effective adsorption of trace levels of Au(III) were optimized with respect to different experimental parameters using batch and column procedures in detail. At pH 3, Au(III) could be quantitatively adsorbed on the new sorbent, and the adsorbed Au(III) could be completely eluted from the sorbent surface by 2.0mL 1.0molL(-1) of HCl+2% CS(NH(2))(2) solution. An enrichment factor of 150 was accomplished. Moreover, common interfering ions did not interfere in both separation and determination. The maximum adsorption capacity of the sorbent for Au(III) was found to be 66.7mgg(-1). The detection limit (3σ) of this method was 0.32μgL(-1) and the relative standard deviation (RSD) was 3.3% (n=8). The method, with high selectivity, sensitivity and reproducibility, was validated using certified reference materials, and had been applied for the determination of trace Au(III) with satisfactory results. Copyright © 2011 Elsevier B.V. All rights reserved.

Problems of Determining the Content of Cr(VI) in Raw Materials and Materials Containing Chromite Ore.

PubMed

Stec, Katarzyna

2017-11-02

Materials made with chromite ore are widely applied in the industry metallurgy as well as in the foundry industry. The oxidation number of chromium in these materials is both (III) and (VI). Currently there are no procedures allowing proper determination of chrome in chromite ores and ore-containing materials. The analytical methods applied, which are dedicated to a very narrow range of materials, e.g., cement, and cannot be applied in the case of materials which, apart from trace amounts of Cr(VI), contain mainly compounds of Cr(III), Fe(III) as well as trace compounds of Cu(II), Ni(II) and V(V). In the work particular attention has been paid to the preparation of test samples and creating measurement conditions in which interferences from Cr(III) and Fe(III) spectral lines could be minimized. Two separate instrumental measurement techniques have been applied: Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP AES) and the spectrophotometric method using diphenylcarbazide.

Imprinted magnetic graphene oxide for the mini-solid phase extraction of Eu (III) from coal mine area

NASA Astrophysics Data System (ADS)

Patra, Santanu; Roy, Ekta; Madhuri, Rashmi; Sharma, Prashant K.

2017-05-01

The present work represents the preparation of imprinted magnetic reduced graphene oxide and applied it for the selective removal of Eu (III) from local coal mines area. A simple solid phase extraction method was used for this purpose. The material shows a very high adsorption as well as removal efficiency towards Eu (III), which suggest that the material have potential to be used in future for their real time applications in removal of Eu (III) from complex matrices.

Structural, magnetic and phonon properties of Cr(III)-doped perovskite metal formate framework [(CH{sub 3}){sub 2}NH{sub 2}][Mn(HCOO){sub 3}

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

Mączka, Mirosław, E-mail: m.maczka@int.pan.wroc.pl; Gągor, Anna; Hermanowicz, Krzysztof

2016-05-15

We have incorporated Cr(III) into [(CH{sub 3}){sub 2}NH{sub 2}][Mn(HCOO){sub 3}] (DMMn) multiferroic metal organic framework (MOF). The highest concentration of Cr(III) in the synthesized samples reached 15.9 mol%. The obtained samples were characterized by powder and single-crystal X-ray diffraction, DSC, magnetic susceptibility, dielectric, EPR, Raman and IR methods. These methods and the performed chemical analysis revealed that electrical charge neutrality after substitution of Cr(III) for Mn(II) is maintained by partial replacement of dimethylammonium (DMA{sup +}) cations by neutral HCOOH molecules. These changes in the chemical composition are responsible for weakening of the hydrogen bonds and decreased flexibility of the framework.more » This in turn leads to lowering of the ferroelectric phase transition temperature, observed around 185 K for undoped DMMn and around 155 K for the sample containing 3.1 mol% of Cr(III), and lack of macroscopic phase transition for the samples with Cr(III) content of 8.2 and 15.9 mol %. Another interesting effect observed for the studied samples is pronounced strengthening of the weak ferromagnetism of in Cr(III)-doped samples, associated with slight decrease of the ferromagnetic ordering temperature from 8.5 K for DMMn to 7.0 K for the sample with 15.9 mol % Cr(III) content. - Graphical abstract: Incorporation of Cr(III) into [(CH3)2NH2[Mn(HCOO)3] framework increases the magnetization. - Highlights: • Chromium(III) substitutes for Mn(II) in the studied MOF. • Charge neutrality is maintained by replacing DMA{sup +} cations by neutral HCOOH molecules. • Compounds with 8.2 and 15.9% of Cr(III) show no phase transition above 100 K. • Doping with Cr(III) increases magnetization.« less

Chemical speciation and recovery of gold(I, III) from wastewater and silver by liquid-liquid extraction with the ion-pair reagent amiloride mono hydrochloride and AAS determination.

PubMed

El-Shahawi, M S; Bashammakh, A S; Bahaffi, S O

2007-06-15

A novel and low cost liquid-liquid extraction procedure for the separation of gold(III) at trace level from aqueous medium of pH 5-9 has been developed. The method has been based upon the formation of a yellow colored ternary complex ion associate of tetrachloro gold(III) complex anion, AuCl(4)(-) with the ion-pair reagent 1-(3,5-diamino-6-chloropyrazinecarboxyl) guanidine hydrochloride monohydrate, namely amiloride, DPG(+).Cl(-). The effect of various parameters, e.g. pH, organic solvent, shaking time, etc. on the preconcentration of gold(III) from the aqueous media by the DPG(+).Cl(-) reagent has been investigated. The colored gold species was quantitatively extracted into 4-methyl pentan-2-one. The chemical composition of the ion associate of DPG(+).Cl(-) with AuCl(4)(-) in the organic solvent has been determined by the Job's method. The molar absorptivity (2.19x10(4)Lmol(-1)cm(-1)) of the associate DPG(+).AuCl(4)(-) at 362nm enabled a convenient application of the developed extraction procedure for the separation and AAS determination of traces of aurate ions. Mono-valence gold ions after oxidation to gold(III) with bromine water in HCl (1.0molL(-1)) media have been also extracted quantitatively from the aqueous media by the developed procedure. The chemical speciation of mono- and/or tri-valence gold species spiked to fresh and industrial wastewater samples has been achieved. The method has been also applied successfully from the separation of gold(I) and gold(III) species from metallic ions and silver. The developed method has also the advantage of freedom from most diverse ions.

Colorimetric detection of genetically modified organisms based on exonuclease III-assisted target recycling and hemin/G-quadruplex DNAzyme amplification.

PubMed

Zhang, Decai; Wang, Weijia; Dong, Qian; Huang, Yunxiu; Wen, Dongmei; Mu, Yuejing; Yuan, Yong

2017-12-21

An isothermal colorimetric method is described for amplified detection of the CaMV 35S promoter sequence in genetically modified organism (GMO). It is based on (a) target DNA-triggered unlabeled molecular beacon (UMB) termini binding, and (b) exonuclease III (Exo III)-assisted target recycling, and (c) hemin/G-quadruplex (DNAzyme) based signal amplification. The specific binding of target to the G-quadruplex sequence-locked UMB triggers the digestion of Exo III. This, in turn, releases an active G-quadruplex segment and target DNA for successive hybridization and cleavage. The Exo III impellent recycling of targets produces numerous G-quadruplex sequences. These further associate with hemin to form DNAzymes and hence will catalyze H 2 O 2 -mediated oxidation of the chromogenic enzyme substrate ABTS 2- causing the formation of a green colored product. This finding enables a sensitive colorimetric determination of GMO DNA (at an analytical wavelength of 420 nm) at concentrations as low as 0.23 nM. By taking advantage of isothermal incubation, this method does not require sophisticated equipment or complicated syntheses. Analyses can be performed within 90 min. The method also discriminates single base mismatches. In our perception, it has a wide scope in that it may be applied to the detection of many other GMOs. Graphical abstract An isothermal and sensitive colorimetric method is described for amplified detection of CaMV 35S promoter sequence in genetically modified organism (GMO). It is based on target DNA-triggered molecular beacon (UMB) termini-binding and exonuclease III assisted target recycling, and on hemin/G-quadruplex (DNAzyme) signal amplification.

40 CFR Figure C-2 to Subpart C of... - Illustration of the Slope and Intercept Limits for Class II and Class III PM 2.5 Candidate...

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 6 2014-07-01 2014-07-01 false Illustration of the Slope and Intercept Limits for Class II and Class III PM 2.5 Candidate Equivalent Methods C Figure C-2 to Subpart C of Part... Candidate Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-2 Figure C-2 to Subpart C of Part 53...

40 CFR Figure C-2 to Subpart C of... - Illustration of the Slope and Intercept Limits for Class II and Class III PM 2.5 Candidate...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Illustration of the Slope and Intercept Limits for Class II and Class III PM 2.5 Candidate Equivalent Methods C Figure C-2 to Subpart C of Part... Candidate Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-2 Figure C-2 to Subpart C of Part 53...

Kinetics and Mechanism of Iodide Oxidation by Iron(III): A Clock Reaction Approach

ERIC Educational Resources Information Center

Bauer, Jurica; Tomisic, Vladislav; Vrkljan, Petar B. A.

2008-01-01

A simple method for studying the kinetics of a chemical reaction is described and the significance of reaction orders in deducing reaction mechanisms is demonstrated. In this student laboratory experiment, oxidation of iodide by iron(III) ions in an acidic medium is transformed into a clock reaction. By means of the initial rates method, it is…

Flower-Like Nanoparticles of Pt-BiIII Assembled on Agmatine Sulfate Modified Glassy Carbon Electrode and Their Electrocatalysis of H2O2

NASA Astrophysics Data System (ADS)

Xiao, Mingshu; Yan, Yuhua; Feng, Kai; Tian, Yanping; Miao, Yuqing

2015-04-01

A new electrochemical technique to detect hydrogen peroxide (H2O2) was developed. The Pt nanoparticles and BiIII were subsequently assembled on agmatine sulfate (AS) modified glassy carbon electrode (GCE) and the prepared GCE-AS-Pt-BiIII was characterized by scanning electron microscopy (SEM) with result showing that the flower-like nanostructure of Pt-BiIII was yielded. Compared with Pt nanoparticles, the flower-like nanostructure of Pt-BiIII greatly enhanced the electrocatalysis of GCE-AS-Pt-BiIII towards H2O2, which is ascribed to more Pt-OH obtained on GCE-AS-Pt-BiIII surface for the presence of BiIII. Based on its high electrocatalysis, GCE-AS-Pt-BiIII was used to determine the content of H2O2 in the sample of sheet bean curd with standard addition method. Meantime, its electrocatalytic activity also was studied.

A novel method for study of the aggregation of protein induced by metal ion aluminum(III) using resonance Rayleigh scattering technique

NASA Astrophysics Data System (ADS)

Long, Xiufen; Zhang, Caihua; Cheng, Jiongjia; Bi, Shuping

2008-01-01

We present a novel method for the study of the aggregation of protein induced by metal ion aluminum(III) using resonance Rayleigh scattering (RRS) technique. In neutral Tris-HCl medium, the effect of this aggregation of protein results in the enhancement of RRS intensity and the relationship between the enhancement of the RRS signal and the Al concentration is nonlinear. On this basis, we established a new method for the determination of the critical induced-aggregation concentrations ( CCIAC) of metal ion Al(III) inducing the protein aggregation. Our results show that many factors, such as, pH value, anions, salts, temperature and solvents have obvious effects. We also studied the extent of aggregation and structural changes using ultra-violet spectrometry, protein intrinsic fluorescence and circular dichroism to further understand the exact mechanisms of the aggregation characteristics of proteins induced by metal ion Al(III) at the molecular level, to help us to develop effective methods to investigate the toxicity of metal ion Al, and to provide theoretical and quantitative evidences for the development of appropriate treatments for neurodementia such as Parkinson's disease, Alzheimer's disease and dementia related to dialysis.

Antiferromagnetic coupling between rare earth ions and semiquinones in a series of 1:1 complexes.

PubMed

Caneschi, Andrea; Dei, Andrea; Gatteschi, Dante; Poussereau, Sandrine; Sorace, Lorenzo

2004-04-07

We use the strategy of diamagnetic substitution for obtaining information on the crystal field effects in paramagnetic rare earth ions using the homologous series of compounds with the diamagnetic tropolonato ligand, Ln(Trp)(HBPz(3))(2), and the paramagnetic semiquinone ligand, Ln(DTBSQ)(HBPz(3))(2), (DTBSQ = 3,5-di-tert-butylsemiquinonato, Trp = tropolonate, HBPz(3)= hydrotrispyrazolylborate) for Ln = Sm(iii), Eu(iii), Gd(iii), Tb(iii), Dy(iii), Ho(iii), Er(iii) or Yb(iii). The X-ray crystal structure of a new form of tropolonate derivative is presented, which shows, as expected, a marked similarity with the structure of the semiquinonate derivative. The Ln(Trp)(HBPz(3))(2) derivatives were then used as a reference for the qualitative determination of crystal field effects in the exchange coupled semiquinone derivatives. Through magnetisation and susceptibility measurements this empirical diamagnetic substitution method evidenced for Er(iii), Tb(iii), Dy(iii) and Yb(iii) derivatives a dominating antiferromagnetic coupling. The increased antiferromagnetic contribution compared to other radical-rare earth metal complexes formed by nitronyl nitroxide ligands may be related to the increased donor strength of the semiquinone ligand.

Impurity-induced disorder in III-nitride materials and devices

DOEpatents

Wierer, Jr., Jonathan J; Allerman, Andrew A

2014-11-25

A method for impurity-induced disordering in III-nitride materials comprises growing a III-nitride heterostructure at a growth temperature and doping the heterostructure layers with a dopant during or after the growth of the heterostructure and post-growth annealing of the heterostructure. The post-growth annealing temperature can be sufficiently high to induce disorder of the heterostructure layer interfaces.

40 CFR 265.1033 - Standards: Closed-vent systems and control devices.

Code of Federal Regulations, 2014 CFR

2014-07-01

... established as a requirement of § 265.1035(b)(4)(iii)(F). (h) An owner or operator using a carbon adsorption..., as determined by the methods specified in paragraph (f)(2)(iii) of this section. (3) A flare shall be... (60 ft/s), except as provided in paragraphs (d)(4) (ii) and (iii) of this section. (ii) A steam...

40 CFR 265.1033 - Standards: Closed-vent systems and control devices.

Code of Federal Regulations, 2013 CFR

2013-07-01

... established as a requirement of § 265.1035(b)(4)(iii)(F). (h) An owner or operator using a carbon adsorption..., as determined by the methods specified in paragraph (f)(2)(iii) of this section. (3) A flare shall be... (60 ft/s), except as provided in paragraphs (d)(4) (ii) and (iii) of this section. (ii) A steam...

40 CFR 265.1033 - Standards: Closed-vent systems and control devices.

Code of Federal Regulations, 2012 CFR

2012-07-01

... established as a requirement of § 265.1035(b)(4)(iii)(F). (h) An owner or operator using a carbon adsorption..., as determined by the methods specified in paragraph (f)(2)(iii) of this section. (3) A flare shall be... (60 ft/s), except as provided in paragraphs (d)(4) (ii) and (iii) of this section. (ii) A steam...

Effect of method of crystallization on the IV-III and IV-II polymorphic transitions of ammonium nitrate.

PubMed

Vargeese, Anuj A; Joshi, Satyawati S; Krishnamurthy, V N

2009-01-15

A study has been undertaken on the effect of crystallization method on the IV<-->III transition of ammonium nitrate (AN). AN is crystallized in three different ways, viz. recrystallization, evaporative crystallization and melt crystallization. When the samples were crystallized from saturated aqueous solution, ideal crystals were formed, which behaved differently from the crystals formed from the other methods. The DTA examination of the crystals showed that the crystals have different transition behaviour. The moisture uptake of the samples determined were found to have influenced by the mode of crystallization. The samples were further analyzed by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The present study showed that the parameters like thermal history, number of previous transformations and moisture content have a very negligible influence on the IV<-->III transition of AN as compared to the method of crystallization.

Cloning of the transgenic pigs expressing human decay accelerating factor and N-acetylglucosaminyltransferase III.

PubMed

Fujimura, Tatsuya; Kurome, Mayuko; Murakami, Hiroshi; Takahagi, Yoichi; Matsunami, Katsuyoshi; Shimanuki, Shinichi; Suzuki, Kohei; Miyagawa, Shuji; Shirakura, Ryota; Shigehisa, Tamotsu; Nagashima, Hiroshi

2004-01-01

The present paper describes production of cloned pigs from fibroblast cells of transgenic pigs expressing human decay accelerating factor (DAF, CD55) and N-acetylglucosaminyltransferase III (GnT-III) that remodels sugar-chain biosynthesis. Two nuclear transfer protocols were used: a two-step activation (TA) method and a delayed activation (DA) method. Enucleated in vitro-matured oocytes and donor cells were electrically fused in a calcium-containing medium by TA method or in a calcium-free medium by DA method, followed by electrical activation 1-1.5 h later, respectively. In vitro blastocyst formation rates of nuclear transferred embryos reconstructed by TA and DA method were 8% and 14%, respectively. As a result of embryo transfer of the reconstructed embryos made by each method into recipient pigs, both gave rise to cloned piglets. These cloned pigs expressed transgene as much as their nuclear donor cells. In conclusions, (1) pig cloning can be carried out by TA or DA nuclear transfer methods, (2) expression of transgenes can be maintained to cloned pigs from the nuclear donor cells derived from transgenic animals.

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

Kawamura, M.; Yoshida, K.; Akabane, S.

We measured endogenous angiotensins (ANGs) I, IIandIII using a system of extraction by Sep-Pak column followed by high performance liquid chromatography (HPLC) combined with radioimmunoassay (RIA). An excellent separation of ANGs was obtained by HPLC. The recovery of ANGs I, IIandIII was 80-84%, when these authentic peptides were added to 6 ml of plasma. The coefficient of variation of the ANGs was 0.04-0.09 for intra-assay and 0.08-0.13 for inter-assay, thereby indicating a good reproducibility. Plasma ANGs I, IIandIII measured by this method in 5 normal volunteers were 51,4.5 and 1.2 pg/ml. In the presence of captopril, ANGs IIandIII decreased bymore » 84% and 77%, respectively, while ANG I increased 5.1 times. This method is therefore useful to assess the precise levels of plasma ANGs.« less

Method of passivating semiconductor surfaces

DOEpatents

Wanlass, M.W.

1990-06-19

A method is described for passivating Group III-V or II-VI semiconductor compound surfaces. The method includes selecting a passivating material having a lattice constant substantially mismatched to the lattice constant of the semiconductor compound. The passivating material is then grown as an ultrathin layer of passivating material on the surface of the Group III-V or II-VI semiconductor compound. The passivating material is grown to a thickness sufficient to maintain a coherent interface between the ultrathin passivating material and the semiconductor compound. In addition, a device formed from such method is also disclosed.

Method of passivating semiconductor surfaces

DOEpatents

Wanlass, Mark W.

1990-01-01

A method of passivating Group III-V or II-VI semiconductor compound surfaces. The method includes selecting a passivating material having a lattice constant substantially mismatched to the lattice constant of the semiconductor compound. The passivating material is then grown as an ultrathin layer of passivating material on the surface of the Group III-V or II-VI semiconductor compound. The passivating material is grown to a thickness sufficient to maintain a coherent interface between the ultrathin passivating material and the semiconductor compound. In addition, a device formed from such method is also disclosed.

MBE growth technology for high quality strained III-V layers

NASA Technical Reports Server (NTRS)

Grunthaner, Frank J. (Inventor); Liu, John K. (Inventor); Hancock, Bruce R. (Inventor)

1990-01-01

The III-V films are grown on large automatically perfect terraces of III-V substrates which have a different lattice constant, with temperature and Group III and V arrival rates chosen to give a Group III element stable surface. The growth is pulsed to inhibit Group III metal accumulation of low temperature, and to permit the film to relax to equilibrium. The method of the invention: (1) minimizes starting step density on sample surface; (2) deposits InAs and GaAs using an interrupted growth mode (0.25 to 2 monolayers at a time); (3) maintains the instantaneous surface stoichiometry during growth (As-stable for GaAs, In-stable for InAs); and (4) uses time-resolved RHEED to achieve aspects (1) through (3).

Crack Growth Mechanisms under Anti-Plane Shear in Composite Laminates

NASA Astrophysics Data System (ADS)

Horner, Allison Lynne

The research conducted for this dissertation focuses on determining the mechanisms associated with crack growth in polymer matrix composite laminates subjected to anti-plane shear (mode III) loading. For mode III split-beam test methods were proposed, and initial evaluations were conducted. A single test method was selected for further evaluation. Using this test method, it was determined that the apparent mode III delamination toughness, GIIIc , depended on geometry, which indicated a true material property was not being measured. Transverse sectioning and optical microscopy revealed an array of transverse matrix cracks, or echelon cracks, oriented at approximately 45° and intersecting the plane of the delamination. Subsequent investigations found the echelon array formed prior to the onset of planar delamination advance and that growth of the planar delamination is always coupled to echelon array formation in these specimens. The evolution of the fracture surfaces formed by the echelon array and planar delamination were studied, and it was found that the development was similar to crack growth in homogenous materials subjected to mode III or mixed mode I-III loading, although the composite laminate architecture constrained the fracture surface development differently than homogenous materials. It was also found that, for split-beam specimens such as those used herein, applying an anti-plane shear load results in twisting of the specimen's uncracked region which gives rise to a mixed-mode I-III load condition. This twisting has been related to the apparent mode III toughness as well as the orientation of the transverse matrix cracks. A finite element model was then developed to study the mechanisms of initial echelon array formation. From this, it is shown that an echelon array will develop, but will become self-limiting prior to the onset of planar delamination growth.

Development of a Dispersive Liquid-Liquid Microextraction Method Combined with UV-Visible Spectrophotometry for Determination of Trace Aluminum(III) in Water, Wastewater, Food, Biological, and Pharmaceutical Samples.

PubMed

Birgani, Nasrin Taghipour; Elhami, Shahla

2017-01-01

A simple and sensitive method was proposed for the preconcentration of trace levels of Al(III) prior to its determination by spectrophotometry, based on dispersive liquid-liquid microextraction. The complexation of the Al(III) was performed by chelation with Eriochrome Cyanine R (ECR). In this method, cetyltrimethyl ammonium bromide (CTAB) as a dispersant was dissolved in chloroform as an extractant solvent, and then the solution was rapidly injected by a syringe into the samples containing Al(III), which had already been complexed by ECR at optimized pH. Various parameters were studied and optimized for a 10 mL sample volume. Under the optimum conditions, the LOD (3 times the SD of 10 replicate readings of the reagent blank) and the dynamic range of the calibration obtained were 0.2 ng mL-1 (7 nM) and 1.0-80.0 ng mL-1, respectively. The RSDs for eight replicate determinations of 10 and 60 ng mL-1 of Al(III) were 3.3 and 1.8%, respectively. This strategy was successfully applied to determine the Al concentration in water, wastewater, yogurt, apple, carrot, celery, bread, potato, urine, and Al-Mg syrup samples.

Eu(III)-Sensitized Luminescence Probe for Determination of Tolnaftate in Pharmaceuticals and Biological Fluids.

PubMed

Alarfaj, Nawal A; El-Tohamy, Maha F

2016-01-01

A highly selective, sensitive, accurate, and reproducible luminescence procedure for determination of antifungal drug tolnaftate was developed. The introduced method was based on the formation of Europa Universalis III (Eu(III))-tolnaftate complex using sodium sulfite as a deoxygenated agent in the presence of acetate buffer (pH = 6) and micellar solution of anionic surfactant sodium dodecyl sulfate. The optimum conditions (effect of pH, buffer, surfactant, Eu(III), and sodium sulfite concentrations) for the luminescence signal were investigated and optimized. The luminescence signals were recorded at λex = 270 nm and λem = 460 nm. The method has a good linear response (0.2-130 μg/mL(-1)) between the luminescence intensity and the concentrations of the drug (r = 0.999), with a LOD 0.07 μg/mL(-1) and LOQ 0.2 μg/mL(-1). The luminescence signals of Eu (III)-tolnaftate-sodium dodecyl sulfate were found to be 200-fold more sensitive without the presence of micelle solution. The interferences of some additives, metals, amino acids, sugars, and other related pharmacological action drugs were examined and no interference was recorded. The proposed method was used for quick and simple determination of tolnaftate in its pharmaceuticals and biological fluids.

Spectrophotometric Determination of Cr(III) and Pb(II) Using Their Complexes with 5,11,17,23-Tetra[(2-ethyl acetoethoxyphenyl)(azo)phenyl]calix[4]arene

PubMed Central

Van Tan, Le; Quang Hieu, Tran; Van Cuong, Nguyen

2015-01-01

New complexes of 5,11,17,23-tetra[(2-ethyl acetoethoxyphenyl)(azo)phenyl]calix[4]arene (TEAC) with Pb(II) and Cr(III) were prepared in basic solution with a mixture of MeOH and H2O as solvent. The ratio of TEAC and metal ion in complexes was found to be 1 : 1 under investigated condition. The complex formation constants (based on Benesi-Hildebrand method) for TEAC-Pb(II) and TEAC-Cr(III) were 4.03 × 104 and 1.2 × 104, respectively. Additionally, the molar extinction coefficients were 5 × 104 and 1.42 × 104 for TEAC-Pb(II) and TEAC-Cr(III), respectively. The H-Point Standard Addition Method (HPSAM) has been applied for simultaneous determination of complexes formation of Cr(III)/Pb(II) and TEAC with concentration from 2 : 1 to 1 : 20 (w/w). The proposed method was successfully utilized to invest lead and chromium contents in plating wastewater samples. The results for several analyzed samples were found to be in satisfied agreement with those acquired by using the inductively coupled plasma mass spectrometry (ICP-MS) technique. PMID:25984379

Copper-Mediated Fluorination of Arylboronate Esters. Identification of a Copper(III) Fluoride Complex

PubMed Central

Fier, Patrick S.; Luo, Jingwei; Hartwig, John F.

2013-01-01

A method for the direct conversion of arylboronate esters to aryl fluorides under mild conditions with readily available reagents is reported. Tandem reactions have also been developed for the fluorination of arenes and aryl bromides through aryl-boronate ester intermediates. Mechanistic studies suggest that this fluorination reaction occurs through facile oxidation of Cu(I) to Cu(III) followed by rate-limiting transmetallation of a bound arylboronate to Cu(III). Fast C-F reductive elimination is proposed to occur from an aryl-copper(III)-fluoride complex. Cu(III) intermediates have been generated independently and identified by NMR spectroscopy and ESI-MS. PMID:23384209

Chemometric methods for the simultaneous determination of some water-soluble vitamins.

PubMed

Mohamed, Abdel-Maaboud I; Mohamed, Horria A; Mohamed, Niveen A; El-Zahery, Marwa R

2011-01-01

Two spectrophotometric methods, derivative and multivariate methods, were applied for the determination of binary, ternary, and quaternary mixtures of the water-soluble vitamins thiamine HCI (I), pyridoxine HCI (II), riboflavin (III), and cyanocobalamin (IV). The first method is divided into first derivative and first derivative of ratio spectra methods, and the second into classical least squares and principal components regression methods. Both methods are based on spectrophotometric measurements of the studied vitamins in 0.1 M HCl solution in the range of 200-500 nm for all components. The linear calibration curves were obtained from 2.5-90 microg/mL, and the correlation coefficients ranged from 0.9991 to 0.9999. These methods were applied for the analysis of the following mixtures: (I) and (II); (I), (II), and (III); (I), (II), and (IV); and (I), (II), (III), and (IV). The described methods were successfully applied for the determination of vitamin combinations in synthetic mixtures and dosage forms from different manufacturers. The recovery ranged from 96.1 +/- 1.2 to 101.2 +/- 1.0% for derivative methods and 97.0 +/- 0.5 to 101.9 +/- 1.3% for multivariate methods. The results of the developed methods were compared with those of reported methods, and gave good accuracy and precision.

Electronic absorption spectral studies of Pr(III) chelates with some amino acids

NASA Astrophysics Data System (ADS)

Kachhawa, Chanchal; Solanki, Kanika; Bhandari, H. S.

2018-05-01

Investigations on Pr(III) systems with 1:1 metal-ligand stoichiometric ratio have been carried out in different solvents. β - Alanine, Taurine and anthranilic acid have been opted as ligands for the investigations. The Study is based on doped crystal phenomenon. The Slater-Condon, spin-orbit, nephelauxetic, bonding, Racah and Judd-Ofelt parameters have been explored during the study. Four bands for Pr(III) have been observed and recorded in the region 350 nm to 900nm. Partial regression method has been used for calculations. Use of computational chemistry has been explored in order to develop better and easier methods of calculations.

30 CFR 934.15 - Approval of North Dakota regulatory program amendments.

Code of Federal Regulations, 2010 CFR

2010-07-01

... dates amendments were submitted to OSM, the dates when the Director's decision approving all, or..., Wetlands standards. II-I, Recreational land use standards for tree and shrub stocking. III-D, Methods for...

Spectroscopic and quantum chemical study of the structure of a new paramagnetic dimeric palladium(II,III) complex with creatine

NASA Astrophysics Data System (ADS)

Mitewa, Mariana; Enchev, Venelin; Bakalova, Tatyana

2002-05-01

The structure and coordination mode of the newly synthesized dimeric paramagnetic Pd(II,III) complex are studied using magneto-chemical, EPR and IR spectroscopic methods. In order to perform reliable assignment of the IR bands, the structure and IR spectrum of the free creatine were calculated using ab initio method. For calculation of the configuration of its deprotonated and doubly deprotonated forms the semiempirical AM1 method was used.

Data Analysis Techniques for Physical Scientists

NASA Astrophysics Data System (ADS)

Pruneau, Claude A.

2017-10-01

Preface; How to read this book; 1. The scientific method; Part I. Foundation in Probability and Statistics: 2. Probability; 3. Probability models; 4. Classical inference I: estimators; 5. Classical inference II: optimization; 6. Classical inference III: confidence intervals and statistical tests; 7. Bayesian inference; Part II. Measurement Techniques: 8. Basic measurements; 9. Event reconstruction; 10. Correlation functions; 11. The multiple facets of correlation functions; 12. Data correction methods; Part III. Simulation Techniques: 13. Monte Carlo methods; 14. Collision and detector modeling; List of references; Index.

40 CFR Figure C-2 to Subpart C of... - Illustration of the Slope and Intercept Limits for Class II and Class III PM2.5 Candidate...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 6 2012-07-01 2012-07-01 false Illustration of the Slope and Intercept Limits for Class II and Class III PM2.5 Candidate Equivalent Methods C Figure C-2 to Subpart C of Part 53... Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-2 Figure C-2 to Subpart C of Part 53—Illustration...

40 CFR Figure C-3 to Subpart C of... - Illustration of the Slope and Intercept Limits for Class II and Class III PM 10-2,5 Candidate...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Illustration of the Slope and Intercept Limits for Class II and Class III PM 10-2,5 Candidate Equivalent Methods C Figure C-3 to Subpart C of... Candidate Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-3 Figure C-3 to Subpart C of Part 53...

40 CFR Figure C-3 to Subpart C of... - Illustration of the Slope and Intercept Limits for Class II and Class III PM10−2.5 Candidate...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Illustration of the Slope and Intercept Limits for Class II and Class III PM10â2.5 Candidate Equivalent Methods C Figure C-3 to Subpart C of Part... Candidate Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-3 Figure C-3 to Subpart C of Part 53...

40 CFR Figure C-3 to Subpart C of... - Illustration of the Slope and Intercept Limits for Class II and Class III PM10−2.5 Candidate...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 6 2012-07-01 2012-07-01 false Illustration of the Slope and Intercept Limits for Class II and Class III PM10â2.5 Candidate Equivalent Methods C Figure C-3 to Subpart C of Part... Candidate Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-3 Figure C-3 to Subpart C of Part 53...

40 CFR Figure C-2 to Subpart C of... - Illustration of the Slope and Intercept Limits for Class II and Class III PM2.5 Candidate...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Illustration of the Slope and Intercept Limits for Class II and Class III PM2.5 Candidate Equivalent Methods C Figure C-2 to Subpart C of Part 53... Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-2 Figure C-2 to Subpart C of Part 53—Illustration...

40 CFR Figure C-3 to Subpart C of... - Illustration of the Slope and Intercept Limits for Class II and Class III PM 10-2.5 Candidate...

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 6 2014-07-01 2014-07-01 false Illustration of the Slope and Intercept Limits for Class II and Class III PM 10-2.5 Candidate Equivalent Methods C Figure C-3 to Subpart C of... Candidate Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-3 Figure C-3 to Subpart C of Part 53...

Army Science Conference Proceedings Held in Orlando, Florida on June 22 - 25, 1992. Volume 3, Principal Authors N Through Z.

DTIC Science & Technology

1992-06-25

SD. The CFA/ll microsphere vaccine (Lot 74F2) percent water content was found using the Karl Fischer titrimeter method to be 2.154% using triplicate...cooling of the reaction is necessary. Under prior synthetic methods the removal of heat has been the rate limiting step, thus necessitating several...Janine I 471 Bhattacharya, P.K. See Tober, Richard L. III 221 Billingsley, Daniel See Watkins, Wendell R. III 275 Binder, Michael Method for Increasing

40 CFR Figure C-2 to Subpart C of... - Illustration of the Slope and Intercept Limits for Class II and Class III PM2.5 Candidate...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Illustration of the Slope and Intercept Limits for Class II and Class III PM2.5 Candidate Equivalent Methods C Figure C-2 to Subpart C of Part 53... Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-2 Figure C-2 to Subpart C of Part 53—Illustration...

40 CFR Figure C-3 to Subpart C of... - Illustration of the Slope and Intercept Limits for Class II and Class III PM10−2.5 Candidate...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Illustration of the Slope and Intercept Limits for Class II and Class III PM10â2.5 Candidate Equivalent Methods C Figure C-3 to Subpart C of Part... Candidate Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-3 Figure C-3 to Subpart C of Part 53...

On-line determination of Sb(III) and total Sb using baker's yeast immobilized on polyurethane foam and hydride generation inductively coupled plasma optical emission spectrometry

NASA Astrophysics Data System (ADS)

Menegário, Amauri A.; Silva, Ariovaldo José; Pozzi, Eloísa; Durrant, Steven F.; Abreu, Cassio H.

2006-09-01

The yeast Saccharomyces cerevisiae was immobilized in cubes of polyurethane foam and the ability of this immobilized material to separate Sb(III) and Sb(V) was investigated. A method based on sequential determination of total Sb (after on-line reduction of Sb(V) to Sb(III) with thiourea) and Sb(III) (after on-line solid-liquid phase extraction) by hydride generation inductively coupled plasma optical emission spectrometry is proposed. A flow system assembled with solenoid valves was used to manage all stages of the process. The effects of pH, sample loading and elution flow rates on solid-liquid phase extraction of Sb(III) were evaluated. Also, the parameters related to on-line pre-reduction (reaction coil and flow rates) were optimized. Detection limits of 0.8 and 0.15 μg L - 1 were obtained for total Sb and Sb(III), respectively. The proposed method was applied to the analysis of river water and effluent samples. The results obtained for the determination of total Sb were in agreement with expected values, including the river water Standard Reference Material 1640 certified by the National Institute of Standards and Technology (NIST). Recoveries of Sb(III) and Sb(V) in spiked samples were between 81 ± 19 and 111 ±15% when 120 s of sample loading were used.

Comparative evaluation of manganese peroxidase- and Mn(III)-initiated peroxidation of C18 unsaturated fatty acids by different methods

Treesearch

Alexander N. Kapich; Tatyana V. Korneichik; Kenneth E. Hammel; Annele Hatakka

2011-01-01

The peroxidation of C18 unsaturated fatty acids by fungal manganese peroxidase (MnP)/Mn(II) and by chelated Mn(III) was studied with application of three different methods: by monitoring oxygen consumption, by measuring conjugated dienes and by thiobarbituric acid-reactive substances (TBARS) formation. All tested polyunsaturated fatty acids (PUFAs) were oxidized by MnP...

Efficient generation of perfluoroalkyl radicals from sodium perfluoroalkanesulfinates and a hypervalent iodine(iii) reagent: mild, metal-free synthesis of perfluoroalkylated organic molecules.

PubMed

Sakamoto, Ryu; Kashiwagi, Hirotaka; Selvakumar, Sermadurai; Moteki, Shin A; Maruoka, Keiji

2016-07-06

This article describes an efficient method for the introduction of perfluoroalkyl groups into N-acrylamides, 2-isocyanides, olefins, and other heterocycles using perfluoroalkyl radicals that were generated from the reaction between sodium perfluoroalkanesulfinates and a hypervalent iodine(iii) reagent. This approach represents a simple, scalable perfluoroalkylation method under mild and metal-free conditions.

40 CFR 52.742 - Incorporation by reference.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Water-Reducible Paints by Direct Injection into a Gas Chromatograph, for § 52.741(a)(4)(i)(B)(3)(iii... Chromatograph, for § 52.741(a)(4)(i)(B)(3)(v). (6) ASTM D2697-86, Standard Test Method for Volume Nonvolatile... Liquids by Isoteniscope, for § 52.741(a)(3), (a)(8)(ii), (a)(9)(iii), and (a)(10)(iii). (11) ASTM D323-82...

Development of a Surface-Enhanced Raman Spectroscopy (SERS)-Based Sensor for the Long Term Monitoring of Toxic Anions

DTIC Science & Technology

2003-06-01

developed a capillary electrophoresis technique that simultaneously detects CrVI and CrIII . In this method, CrIII is reacted with MoVI to form a...CrVI was not affected by the presence of a 103-fold excess of CrIII . The pyridinium coating showed great selectivity for the CrVI species. The...metals are analyzed using ICP, which cannot differentiate between CrVI and CrIII species. Analytical costs can range anywhere between $50.00 and

Dysprosium sorption by polymeric composite bead: robust parametric optimization using Taguchi method.

PubMed

Yadav, Kartikey K; Dasgupta, Kinshuk; Singh, Dhruva K; Varshney, Lalit; Singh, Harvinderpal

2015-03-06

Polyethersulfone-based beads encapsulating di-2-ethylhexyl phosphoric acid have been synthesized and evaluated for the recovery of rare earth values from the aqueous media. Percentage recovery and the sorption behavior of Dy(III) have been investigated under wide range of experimental parameters using these beads. Taguchi method utilizing L-18 orthogonal array has been adopted to identify the most influential process parameters responsible for higher degree of recovery with enhanced sorption of Dy(III) from chloride medium. Analysis of variance indicated that the feed concentration of Dy(III) is the most influential factor for equilibrium sorption capacity, whereas aqueous phase acidity influences the percentage recovery most. The presence of polyvinyl alcohol and multiwalled carbon nanotube modified the internal structure of the composite beads and resulted in uniform distribution of organic extractant inside polymeric matrix. The experiment performed under optimum process conditions as predicted by Taguchi method resulted in enhanced Dy(III) recovery and sorption capacity by polymeric beads with minimum standard deviation. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of alkaline precipitation on Cr species of Cr(III)-bearing complexes typically used in the tannery industry.

PubMed

Wang, Dandan; Ye, Yuxuan; Liu, Hui; Ma, Hongrui; Zhang, Weiming

2018-02-01

Various organic compounds extensively used in the leather industry could influence the performance of alkaline precipitation with Cr(III). This study focused on two typical Cr(III)-bearing complexes (Cr(III)-collagen and Cr(III)-citrate) ubiquitous in tannery effluent yet with distinct treatment efficiencies, as Cr(III) was much more difficult to remove in the Cr(III)-citrate solution. Comprehensive analytical methods were employed to explore the intrinsic mechanism. It was found that a lower removal efficiency towards Cr(III) was significantly associated with higher oligomers. The molecular size of the Cr(III)-citrate complex continued to increase with rising pH, making it larger overall than Cr(III)-collagen species. The growing oligomer moiety of dissolved Cr(III)-complex species could persist in the stronger basic pH range, leading to the large amount of residual Cr(III) in the Cr(III)-citrate system. Combining this result with potentiometric titration and X-ray photoelectron spectroscopy data, it was believed that the polymeric species other than monomers facilitated resisting the attack from hydroxide ions, and the postulated Cr(III)-citrate species towards higher oligomers were discovered. Beyond that, both charge neutralization and sweeping effects were presented among the gradually emerging flocs in the Cr(III)-collagen system together with the electric double layer compression effect derived from salinity, thus resulting in a larger floc size and higher Cr(III) removal efficiency in saline solutions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis of Er(III)/Yb(III)-doped BiF3 upconversion nanoparticles for use in optical thermometry.

PubMed

Du, Peng; Yu, Jae Su

2018-03-23

The authors describe an ethylene glycol assisted precipitation method for synthesis of Er(III)/Yb(III)-doped BiF 3 nanoparticles (NPs) at room temperature. Under 980-nm light irradiation, the NPs emit upconversion (UC) emission of Er(III) ions as a result of a two-photon absorption process. The temperature-dependent green emissions (peaking at 525 and 545 nm) are used to establish an unambiguous relationship between the ratio of fluorescence intensities and temperature. The NPs have a maximum sensitivity of 6.5 × 10 -3  K -1 at 619 K and can be applied over the 291-691 K temperature range. The results indicate that these NPs are a promising candidate for optical thermometry. Graphical abstract Schematic of the room-temperature preparation of Er(III)/Yb(III)-doped BiF 3 nanoparticles with strongly temperature-dependent upconversion emission.

Design and synthesis of novel adenine fluorescence probe based on Eu(III) complexes with dtpa-bis(guanine) ligand

NASA Astrophysics Data System (ADS)

Tian, Fengyun; Jiang, Xiaoqing; Dou, Xuekai; Wu, Qiong; Wang, Jun; Song, Youtao

2017-05-01

A novel adenine (Ad) fluorescence probe (EuIII-dtpa-bis(guanine)) was designed and synthesized by improving experimental method based on the Eu(III) complex and dtpa-bis(guanine) ligand. The dtpa-bis(guanine) ligand was first synthesized by the acylation action between dtpaa and guanine (Gu), and the corresponding Eu(III) complex was successfully prepared through heat-refluxing method with dtpa-bis(guanine) ligand. As a novel fluorescence probe, the EuIII-dtpa-bis(guanine) complex can detect adenine (Ad) with characteristics of strong targeting, high specificity and high recognition ability. The detection mechanism of the adenine (Ad) using this probe in buffer solution was studied by ultraviolet-visible (UV-vis) and fluorescence spectroscopy. When the EuIII-dtpa-bis(guanine) was introduced to the adenine (Ad) solution, the fluorescence emission intensity was significantly enhanced. However, adding other bases such as guanine (Gu), xanthine (Xa), hypoxanthine (Hy) and uric acid (Ur) with similar composition and structure to that of adenine (Ad) to the EuIII-dtpa-bis(guanine) solution, the fluorescence emission intensities are nearly invariable. Meanwhile, the interference of guanine (Gu), xanthine (Xa), hypoxanthine (Hy) and uric acid (Ur) on the detection of the adenine using EuIII-dtpa-bis(guanine) probe was also studied. It was found that presence of these bases does not affect the detection of adenine (Ad). A linear response of fluorescence emission intensities of EuIII-dtpa-bis(guanine) at 570 nm as a function of adenine (Ad) concentration in the range of 0.00-5.00 × 10- 5 mol L- 1 was observed. The detection limit is about 4.70 × 10- 7 mol L- 1.

Combination of X-ray crystallography, SAXS and DEER to obtain the structure of the FnIII-3, 4 domains of integrin α6β4

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

Alonso-García, Noelia; García-Rubio, Inés; Academia General Militar, Carretera de Huesca s/n, 50090 Zaragoza

The structure of the FnIII-3, 4 region of integrin β4 was solved using a hybrid approach that combines crystallographic structures, SAXS, DEER and molecular modelling. The structure helps in understanding how integrin β4 might bind to other hemidesmosomal proteins and mediate signalling. Integrin α6β4 is a major component of hemidesmosomes that mediate the stable anchorage of epithelial cells to the underlying basement membrane. Integrin α6β4 has also been implicated in cell proliferation and migration and in carcinoma progression. The third and fourth fibronectin type III domains (FnIII-3, 4) of integrin β4 mediate binding to the hemidesmosomal proteins BPAG1e and BPAG2,more » and participate in signalling. Here, it is demonstrated that X-ray crystallography, small-angle X-ray scattering and double electron–electron resonance (DEER) complement each other to solve the structure of the FnIII-3, 4 region. The crystal structures of the individual FnIII-3 and FnIII-4 domains were solved and the relative arrangement of the FnIII domains was elucidated by combining DEER with site-directed spin labelling. Multiple structures of the interdomain linker were modelled by Monte Carlo methods complying with DEER constraints, and the final structures were selected against experimental scattering data. FnIII-3, 4 has a compact and cambered flat structure with an evolutionary conserved surface that is likely to correspond to a protein-interaction site. Finally, this hybrid method is of general application for the study of other macromolecules and complexes.« less

Novel Luminescent Probe Based on a Terbium(III) Complex for Hemoglobin Determination

NASA Astrophysics Data System (ADS)

Yegorova, A. V.; Leonenko, I. I.; Aleksandrova, D. I.; Scrypynets, Yu. V.; Antonovich, V. P.; Ukrainets, I. V.

2014-09-01

We have studied the spectral luminescent properties of Tb(III) and Eu(III) complexes with a number of novel derivatives of oxoquinoline-3-carboxylic acid amides (L1-L5 ). We have observed quenching of the luminescence of 1:1 Tb(III)-L1-5 complexes by hemoglobin (Hb), which is explained by resonance energy transfer of electronic excitation from the donor (Tb(III)-L1-5 ) to the acceptor (Hb). Using the novel luminescent probe Tb(III)-L1, we have developed a method for determining Hb in human blood. The calibration Stern-Volmer plot is linear in the Hb concentration range 0.6-36.0 μg/mL, detection limit 0.2 μg/mL (3·10-9 mol/L).

Development and application of a method for Cr(III) determination in dairy products by HPLC-ICP-MS.

PubMed

Hernandez, Fanny; Jitaru, Petru; Cormant, Florence; Noël, Laurent; Guérin, Thierry

2018-02-01

This study describes the development of an analytical approach for the determination of Cr(III) in dairy products by microwave assisted extraction, complexation in situ by ethylenediaminetetraacetate (EDTA) and high performance liquid chromatography hyphenated to inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). The extraction step was optimised by using an experimental design. A limit of quantification of 38µgkg -1 dry weight (d.w.) was obtained whereas the bias (%) measured ranged from 10 to 18%. The repeatability and intermediate precision varied between 1.2-5.0% and 7.5-13.5%, respectively. The method was applied to the analysis of several dairy samples beforehand characterized in terms of Cr(VI) and total chromium (Cr total ). Cr(III) concentrations ranged from <13 to 255µgkg -1 d.w. The results showed a good agreement between Cr(III) and Cr total concentration levels. Copyright © 2017 Elsevier Ltd. All rights reserved.

Lattice matched crystalline substrates for cubic nitride semiconductor growth

DOEpatents

Norman, Andrew G; Ptak, Aaron J; McMahon, William E

2015-02-24

Disclosed embodiments include methods of fabricating a semiconductor layer or device and devices fabricated thereby. The methods include, but are not limited to, providing a substrate having a cubic crystalline surface with a known lattice parameter and growing a cubic crystalline group III-nitride alloy layer on the cubic crystalline substrate by coincident site lattice matched epitaxy. The cubic crystalline group III-nitride alloy may be prepared to have a lattice parameter (a') that is related to the lattice parameter of the substrate (a). The group III-nitride alloy may be a cubic crystalline In.sub.xGa.sub.yAl.sub.1-x-yN alloy. The lattice parameter of the In.sub.xGa.sub.yAl.sub.1-x-yN or other group III-nitride alloy may be related to the substrate lattice parameter by (a')= 2(a) or (a')=(a)/ 2. The semiconductor alloy may be prepared to have a selected band gap.

Linear scan voltammetric indirect determination of Al(III) by the catalytic cathodic response of norepinephrine at the hanging mercury drop electrode.

PubMed

Zhang, Fuping; Ji, Ming; Xu, Quan; Yang, Li; Bi, Shuping

2005-09-01

The biological effects of aluminum (Al) have received much attention in recent years. Al is of basic relevance as concern with its reactivity and bioavailability. In this paper, the electrochemical behaviors of norepinephrine (NE) in the absence and presence of Al(III) at the hanging mercury drop electrode have been studied and applied to the practical analysis. Highly selective catalytic cathodic peak of NE is yielded by linear scan voltammetry (LSV) at -1.32 V (vs. SCE). A linear relationship holds between the cathodic peak current and the Al(III) concentration. It has been successfully applied to the determination of Al(III) in real waters and synthetic biological samples with satisfying results, which are in accordance with those obtained by ICP-AES method. The electrochemical properties and the mechanisms of the peaks in the presence and absence of Al(III) have been explored. The results show that they are irreversible adsorptive hydrogen catalytic waves. These studies not only enrich the methods of determining Al, but also lay foundations of further understanding of the mechanisms of neurodementia.

Extraction of carrier mobility and interface trap density in InGaAs metal oxide semiconductor structures using gated Hall method

NASA Astrophysics Data System (ADS)

Chidambaram, Thenappan

III-V semiconductors are potential candidates to replace Si as a channel material in next generation CMOS integrated circuits owing to their superior carrier mobilities. Low density of states (DOS) and typically high interface and border trap densities (Dit) in high mobility group III-V semiconductors provide difficulties in quantification of Dit near the conduction band edge. The trap response above the threshold voltage of a MOSFET can be very fast, and conventional Dit extraction methods, based on capacitance/conductance response (CV methods) of MOS capacitors at frequencies <1MHz, cannot distinguish conducting and trapped carriers. In addition, the CV methods have to deal with high dispersion in the accumulation region that makes it a difficult task to measure the true oxide capacitance, Cox value. Another implication of these properties of III-V interfaces is an ambiguity of determination of electron density in the MOSFET channel. Traditional evaluation of carrier density by integration of the C-V curve, gives incorrect values for D it and mobility. Here we employ gated Hall method to quantify the D it spectrum at the high-K oxide/III-V semiconductor interface for buried and surface channel devices using Hall measurement and capacitance-voltage data. Determination of electron density directly from Hall measurements allows for obtaining true mobility values.

Analysis for nickel (3 and 4) in positive plates from nickel-cadmium cells

NASA Technical Reports Server (NTRS)

Lewis, Harlan L.

1994-01-01

The NASA-Goddard procedure for destructive physical analysis (DPA) of nickel-cadmium cells contains a method for analysis of residual charged nickel as NiOOH in the positive plates at complete cell discharge, also known as nickel precharge. In the method, the Ni(III) is treated with an excess of an Fe(II) reducing agent and then back titrated with permanganate. The Ni(III) content is the difference between Fe(II) equivalents and permanganate equivalents. Problems have arisen in analysis at NAVSURFWARCENDIV, Crane because for many types of cells, particularly AA-size and some 'space-qualified' cells, zero or negative Ni(III) contents are recorded for which the manufacturer claims 3-5 percent precharge. Our approach to this problem was to reexamine the procedure for the source of error, and correct it or develop an alternative method.

Monosodium glutamate for simple photometric iron analysis

NASA Astrophysics Data System (ADS)

Prasetyo, E.

2018-01-01

Simple photometric method for iron analysis using monosodium glutamate (MSG) was proposed. The method could be used as an alternative method, which was technically simple, economic, quantitative, readily available, scientifically sound and environmental friendly. Rapid reaction of iron (III) with glutamate in sodium chloride-hydrochloric acid buffer (pH 2) to form red-brown complex was served as a basis in the photometric determination, which obeyed the range of iron (III) concentration 1.6 - 80 µg/ml. This method could be applied to determine iron concentration in soil with satisfactory results (accuracy and precision) compared to other photometric and atomic absorption spectrometry results.

Exchange coupling and magnetic anisotropy in a family of bipyrimidyl radical-bridged dilanthanide complexes: density functional theory and ab initio calculations.

PubMed

Zhang, Yi-Quan; Luo, Cheng-Lin; Zhang, Qiang

2014-05-05

The origin of the magnetic anisotropy energy barriers in a series of bpym(-) (bpym = 2,2'-bipyrimidine) radical-bridged dilanthanide complexes [(Cp*2Ln)2(μ-bpym)](+) [Cp* = pentamethylcyclopentadienyl; Ln = Gd(III) (1), Tb(III) (2), Dy(III) (3), Ho(III) (4), Er(III) (5)] has been explored using density functional theory (DFT) and ab initio methods. DFT calculations show that the exchange coupling between the two lanthanide ions for each complex is very weak, but the antiferromagnetic Ln-bpym(-) couplings are strong. Ab initio calculations show that the effective energy barrier of 2 or 3 mainly comes from the contribution of a single Tb(III) or Dy(III) fragment, which is only about one third of a single Ln energy barrier. For 4 or 5, however, both of the two Ho(III) or Er(III) fragments contribute to the total energy barrier. Thus, it is insufficient to only increase the magnetic anisotropy energy barrier of a single Ln ion, while enhancing the Ln-bpym(-) couplings is also very important. Copyright © 2014 Wiley Periodicals, Inc.

Quantitative determination of juvenile hormone III and 20-hydroxyecdysone in queen larvae and drone pupae of Apis mellifera by ultrasonic-assisted extraction and liquid chromatography with electrospray ionization tandem mass spectrometry.

PubMed

Zhou, Jinhui; Qi, Yitao; Hou, Yali; Zhao, Jing; Li, Yi; Xue, Xiaofeng; Wu, Liming; Zhang, Jinzhen; Chen, Fang

2011-09-01

In this paper, a method for the rapid and sensitive analysis of juvenile hormone III (JH III) and 20-hydroxyecdysone (20E) in queen larvae and drone pupae samples was presented. Ultrasound-assisted extraction provided a significant shortening of the leaching time for the extraction of JH III and 20E and satisfactory sensitivity as compared to the conventional shake extraction procedure. After extraction, determination was carried out by liquid chromatography-tandem mass spectrometry (LC-MS/MS) operating in electrospray ionization positive ion mode via multiple reaction monitoring (MRM) without any clean-up step prior to analysis. A linear gradient consisting of (A) water containing 0.1% formic acid and (B) acetonitrile containing 0.1% formic acid, and a ZORBAX SB-Aq column (100 mm × 2.1 mm, 3.5 μm) were employed to obtain the best resolution of the target analytes. The method was validated for linearity, limit of quantification, recovery, matrix effects, precision and stability. Drone pupae samples were found to contain 20E at concentrations of 18.0 ± 0.1 ng/g (mean ± SD) and JH III was detected at concentrations of 0.20 ± 0.06 ng/g (mean ± SD) in queen larvae samples. This validated method provided some practical information for the actual content of JH III and 20E in queen larvae and drone pupae samples. Copyright © 2011 Elsevier B.V. All rights reserved.

Rapid screening test for porphyria diagnosis using fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Lang, A.; Stepp, H.; Homann, C.; Hennig, G.; Brittenham, G. M.; Vogeser, M.

2015-07-01

Porphyrias are rare genetic metabolic disorders, which result from deficiencies of enzymes in the heme biosynthesis pathway. Depending on the enzyme defect, different types of porphyrins and heme precursors accumulate for the different porphyria diseases in erythrocytes, liver, blood plasma, urine and stool. Patients with acute hepatic porphyrias can suffer from acute neuropathic attacks, which can lead to death when undiagnosed, but show only unspecific clinical symptoms such as abdominal pain. Therefore, in addition to chromatographic methods, a rapid screening test is required to allow for immediate identification and treatment of these patients. In this study, fluorescence spectroscopic measurements were conducted on blood plasma and phantom material, mimicking the composition of blood plasma of porphyria patients. Hydrochloric acid was used to differentiate the occurring porphyrins (uroporphyrin-III and coproporphyrin-III) spectroscopically despite their initially overlapping excitation spectra. Plasma phantom mixtures were measured using dual wavelength excitation and the corresponding concentrations of uroporphyrin-III and coproporphyrin-III were determined. Additionally, three plasma samples of porphyria patients were examined and traces of coproporphyrin-III and uroporphyrin-III were identified. This study may therefore help to establish a rapid screening test method with spectroscopic differentiation of the occurring porphyrins, which consequently allows for the distinction of different porphyrias. This may be a valuable tool for clinical porphyria diagnosis and rapid or immediate treatment.

The Effect of Pressure and Temperature on Separation of Free Gadolinium(III) From Gd-DTPA Complex by Nanofiltration-Complexation Method

NASA Astrophysics Data System (ADS)

Rahayu, Iman; Anggraeni, Anni; Ukun, MSS; Bahti, Husein H.

2017-05-01

Nowdays, the utilization of rare earth elements has been carried out widely in industry and medicine, one of them is gadolinium in Gd-DTPA complex is used as a contrast agent in a magnetic resonance imaging (MRI) diagnostic to increase the visual contrast between normal tissue and diseased. Although the stability of a given complex may be high enough, the complexation step couldnot have been completed, so there is possible to gadolinium(III) in the complex compound. Therefore, the function of that compounds should be dangerous because of the toxicity of gadolinium(III) in human body. So, it is necessarry to separate free gadolinium(III) from Gd-DTPA complex by nanofiltration-complexation. The method of this study is complexing of Gd2O3 with DTPA ligand by reflux and separation of Gd-DTPA complex from gadolinium(III) with a nanofiltration membrane on the variation of pressures(2, 3, 4, 5, 6 bars) and temperature (25, 30, 35, 40 °C) and determined the flux and rejection. The results of this study are the higher of pressures and temperatures, permeation flux are increasing and ion rejections are decreasing and gave the free gadolinium(III) rejection until 86.26%.

[Determination of trivalent chromium and hexavalent chromium in dried edible fungi by microwave ashing-liquid chromatography with inductively coupled plasma mass spectrometry].

PubMed

Ni, Zhanglin; Tang, Fubin; Qu, Minghua; Mo, Runhong

2014-02-01

An analytical method using liquid chromatography with inductively coupled plasma mass spectrometry (LC-ICP-MS) for the determination of trivalent chromium (Cr(III)) and hexavalent chromium (Cr(VI)) in dried edible fungi was established. Edible fungi sample was ashed by a microwave ashing system and Na2 EDTA was added to the ashing sample to stabilize the Cr(III). An anion exchange column (250 mm x 4.6 mm, 10 microm) with a 60 mmol/L nitric acid (pH 9.3) solution as mobile phase was used for the separation and using ICP-MS as a detector for the determination of trivalent chromium and hexavalent chromium. The calibration curves were linear in the range of 0.5-50 microg/L and the correlation coefficients were 0. 999 9 for Cr(III) and Cr(VI). The average recoveries of Cr(III) and Cr(VI) ranged from 78.0% to 90.7% with the relative standard deviations (RSDs, n = 6) less than 4%. The limits of quantification (LOQ) of Cr(III) and Cr(VI) were 0.5 microg/L. The method is efficient, reliable and sensitive, and can meet the requirement for the determination of Cr(III) and Cr(VI) in dried edible fungi.

Selective speciation and determination of inorganic arsenic in water, food and biological samples.

PubMed

Tuzen, Mustafa; Saygi, Kadriye Ozlem; Karaman, Isa; Soylak, Mustafa

2010-01-01

A procedure for the speciation of arsenic(III) and arsenic(V) in natural water samples has been established in the presented work. Arsenic(III) ions were quantitatively recovered on Alternaria solani coated Diaion HP-2MG resin at pH 7, while the recoveries of arsenic(V) was below 10%. Arsenic(V) in the mixing solution containing As(III) and As(V) was reduced by using KI and L(+) ascorbic acid solution, then the procedure was applied to determination of total arsenic. Arsenic(V) was calculated as the difference between the total arsenic content and As(III) content. The determination of arsenic was performed by using hydride generation atomic absorption spectrometry. The influences of some alkali, earth alkali and transition metals on the biosorption of arsenic(III) were investigated. The preconcentration factor was 35. The detection limits for As(III) (N=20, k=3) was found as 11 ng L(-1). The relative standard deviation and relative error of the determinations were found to be lower than 7% and 4%, respectively. The accuracy of the method was confirmed with certified reference materials. The method was successively applied for the determination and speciation of inorganic arsenic in water, food and biological samples. Copyright 2009 Elsevier Ltd. All rights reserved.

Layer by Layer Growth of 2D Quantum Superlattices (NBIT III)

DTIC Science & Technology

2017-02-28

building quantum superlatticies using 2D materials as the building blocks. Specifically, we develop methods that allow i) large-scale growth of aligned...superlattice and heterostructures, iii) lateral and clean patterning of 2D materials for atomically-thin circuitry and iv) novel physical properties...high precision and flexibility beyond conventional methods. Moreover, it provides the solutions for current major barrier for 2D materials (e.g

Role of the He I and He II metastables in the resonance 2p 2P°1/2, 3/2 B III level population

NASA Astrophysics Data System (ADS)

Djeniže, S.; Srećković, A.; Bukvić, S.

2007-01-01

Aims:The aim of this work is to present atomic processes which lead to an extra population of the 2p ~^2P°1/2, 3/2 B III resonance levels in helium plasma generating intense radiation in the B III 206.578 nm and 206.723 nm lines. Methods: The line profiles were recorded using a step-by-step (7.3 pm) technique which provides monitoring of the line shapes continually during the plasma decay and gives the possibility to compare line shapes at various times in the same plasma. Results: On the basis of the line intensity decays of the doubly ionized boron resonance spectral lines in laboratory nitrogen and helium plasmas, we have found the existence of a permanent energy transfer from He I and He II metastables to the 2p ^2P°1/2, 3/2 B III resonance levels. The shapes of the mentioned lines are also observed. At electron temperatures of about 18 000 K and electron densities about 1.1× 1023 m-3, the Stark broadening was found as a main B III line broadening mechanism. The measured Stark widths (W) are compared with the Doppler width (W_D) and with the splitting in the hyperfine structure (Δ_hfs). Our measured W data are found to be much higher than results obtained by means of various theoretical approaches. Conclusions: . The He I and He II metastables over populate the B III resonance levels leading to populations higher than predicted by LTE model. Consequently, the emitted B III resonance lines are more intense than expected from LTE model. This fact can be of importance if B III resonance line intensities are used for abundance determination purposes in astrophysics. Similar behavior can be expected for some lines emitted by astrophysical interesting emitters: Al III, Si III, Sc III, Cr III, V III, Ti III, Fe III, Co III, Ni III, Ga III, Zr III, Y III, Nb III, In III, Sn III, Sb III, Au III, Pb III and Bi III in hot and dense helium plasmas.

Molecular and electronic structure of thin films of protoporphyrin(IX)Fe(III)Cl

NASA Astrophysics Data System (ADS)

Snyder, Shelly R.; White, Henry S.

1991-11-01

Electrochemical, scanning tunneling microscopy (STM), and tunneling spectroscopy studies of the molecular and electronic properties of thin films of protoporphyrin(IX)Fe(III)Cl (abbreviated as PP(IX)Fe(III)Cl) on highly oriented pyrolytic graphite (HOPG) electrodes are reported. PP(IX)Fe(III)Cl films are prepared by two different methods: (1) adsorption, yielding an electrochemically-active film, and (2) irreversible electrooxidative polymerization, yielding an electrochemically-inactive film. STM images, in conjunction with electro-chemical results, indicate that adsorption of PP(IX)Fe(III)Cl from aqueous solutions onto freshly cleaved HOPG results in a film comprised of molecular aggregates. In contrast, films prepared by irreversible electrooxidative polymerization of PP(IX)Fe(III)Cl have a denser, highly structured morphology, including what appear to be small pinholes (approx. 50A diameter) in an otherwise continuous film.

Half-metallicity and electronic structures for carbon-doped group III-nitrides: Calculated with a modified Becke-Johnson potential

NASA Astrophysics Data System (ADS)

Fan, Shuai-wei; Wang, Ri-gao; Xu, Pemg

2016-09-01

The electronic structures and magnetism for carbon-doped group III-nitrides are investigated by utilizing the first principle method with the modified Becke-Johnson potential. Calculations show that carbon substituting cations (anions) would induce the group III-nitrides to be paramagnetic metals (half-metallic ferromagnets). Single carbon substituting nitrogen could produce 1.00μB magnetic moment. Electronic structures indicate that the carriers-mediated double-exchange interaction plays a crucial role in forming the ferromagnetism. Based on the mean-field theory, the Curie temperature for carbon-doped group III-nitrides would be above the room temperature. Negative chemical pair interactions imply that carbon dopants tend to form clustering distribution in group III-nitrides. The nitrogen vacancy would make the carbon-doped group III-nitrides lose the half-metallic ferromagnetism.

Routine Treatment of Cervical Cytological Cell Changes

PubMed Central

Huber, J.; Pötsch, B.; Gantschacher, M.; Templ, M.

2016-01-01

Introduction: Diagnosis and treatment of vaginal and cervical cytological cell changes are described in European and national guidelines. The aim of this data collection was to evaluate the remission rates of PAP III and PAP III D cytological findings in patients over a period of 3–4 months. Method: The current state of affairs in managing suspicious and cytological findings (PAP III, and III D) in gynecological practice was assessed in the context of a data collection survey. An evaluation over a period of 24 months was conducted on preventative measures, the occurrence and changes to normal/suspect/pathological findings and therapy management (for suspicious or pathological findings). Results: 307 female patients were included in the analysis. At the time of the survey 186 patients (60.6 %) had PAP III and 119 (38.8 %) had PAP III D findings. The spontaneous remission rate of untreated PAP III patients was 6 % and that of untreated PAP III D patients was 11 %. The remission rates of patients treated with a vaginal gel were 77 % for PAP III and 71 % for PAP III D. Conclusion: A new treatment option was used in gynecological practice on patients with PAP III and PAP III D findings between confirmation and the next follow-up with excellent success. PMID:27761030

Validated spectrophotometric methods for determination of Alendronate sodium in tablets through nucleophilic aromatic substitution reactions

PubMed Central

2012-01-01

Background Alendronate (ALD) is a member of the bisphosphonate family which is used for the treatment of osteoporosis, bone metastasis, Paget's disease, hypocalcaemia associated with malignancy and other conditions that feature bone fragility. ALD is a non-chromophoric compound so its determination by conventional spectrophotometric methods is not possible. So two derivatization reactions were proposed for determination of ALD through the reaction with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) and 2,4-dinitrofluorobenzene (DNFB) as chromogenic derivatizing reagents. Results Three simple and sensitive spectrophotometric methods are described for the determination of ALD. Method I is based on the reaction of ALD with NBD-Cl. Method II involved heat-catalyzed derivatization of ALD with DNFB, while, Method III is based on micellar-catalyzed reaction of the studied drug with DNFB at room temperature. The reactions products were measured at 472, 378 and 374 nm, for methods I, II and III, respectively. Beer's law was obeyed over the concentration ranges of 1.0-20.0, 4.0-40.0 and 1.5-30.0 μg/mL with lower limits of detection of 0.09, 1.06 and 0.06 μg/mL for Methods I, II and III, respectively. The proposed methods were applied for quantitation of the studied drug in its pure form with mean percentage recoveries of 100.47 ± 1.12, 100.17 ± 1.21 and 99.23 ± 1.26 for Methods I, II and III, respectively. Moreover the proposed methods were successfully applied for determination of ALD in different tablets. Proposals of the reactions pathways have been postulated. Conclusion The proposed spectrophotometric methods provided sensitive, specific and inexpensive analytical procedures for determination of the non-chromophoric drug alendronate either per se or in its tablet dosage forms without interference from common excipients. Graphical abstract PMID:22472190

Validated spectrophotometric methods for determination of Alendronate sodium in tablets through nucleophilic aromatic substitution reactions.

PubMed

Walash, Mohamed I; Metwally, Mohamed E-S; Eid, Manal; El-Shaheny, Rania N

2012-04-02

Alendronate (ALD) is a member of the bisphosphonate family which is used for the treatment of osteoporosis, bone metastasis, Paget's disease, hypocalcaemia associated with malignancy and other conditions that feature bone fragility. ALD is a non-chromophoric compound so its determination by conventional spectrophotometric methods is not possible. So two derivatization reactions were proposed for determination of ALD through the reaction with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) and 2,4-dinitrofluorobenzene (DNFB) as chromogenic derivatizing reagents. Three simple and sensitive spectrophotometric methods are described for the determination of ALD. Method I is based on the reaction of ALD with NBD-Cl. Method II involved heat-catalyzed derivatization of ALD with DNFB, while, Method III is based on micellar-catalyzed reaction of the studied drug with DNFB at room temperature. The reactions products were measured at 472, 378 and 374 nm, for methods I, II and III, respectively. Beer's law was obeyed over the concentration ranges of 1.0-20.0, 4.0-40.0 and 1.5-30.0 μg/mL with lower limits of detection of 0.09, 1.06 and 0.06 μg/mL for Methods I, II and III, respectively. The proposed methods were applied for quantitation of the studied drug in its pure form with mean percentage recoveries of 100.47 ± 1.12, 100.17 ± 1.21 and 99.23 ± 1.26 for Methods I, II and III, respectively. Moreover the proposed methods were successfully applied for determination of ALD in different tablets. Proposals of the reactions pathways have been postulated. The proposed spectrophotometric methods provided sensitive, specific and inexpensive analytical procedures for determination of the non-chromophoric drug alendronate either per se or in its tablet dosage forms without interference from common excipients. GRAPHICAL

Extraction and determination of arsenic species in leafy vegetables: Method development and application.

PubMed

Ma, Li; Yang, Zhaoguang; Kong, Qian; Wang, Lin

2017-02-15

Extraction of arsenic (As) species in leafy vegetables was investigated by different combinations of methods and extractants. The extracted As species were separated and determined by HPLC-ICP-MS method. The microwave assisted method using 1% HNO3 as the extractant exhibited satisfactory efficiency (>90%) at 90°C for 1.5h. The proposed method was applied for extracting As species from real leafy vegetables. Thirteen cultivars of leafy vegetables were collected and analyzed. The predominant species in all the investigated vegetable samples were As(III) and As(V). Moreover, both As(III) and As(V) concentrations were positive significant (p<0.01) correlated with total As (tAs) concentration. However, the percentage of As(V) reduced with tAs concentration increasing probably due to the conversion and transformation of As(V) to As(III) after uptake. The hazard quotient results indicated no particular risk to 94.6% of local consumers. Considerably carcinogenic risk by consumption of the leafy vegetables was observed. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Identification of early irreversible damage area in a rat model of cerebral ischemia and reperfusion].

PubMed

Liu, S; Guo, Y

2000-02-01

To observe the early neuron ischemic damage in focal cerebral ischemia/reperfusion with histostaining methods of argyrophil III (AG III), Toludine blue(TB), and H&E, and to make out the 'separating line' between the areas of reversible and irreversible early ischemic damage. Forty-two male Wistar rats were randomly divided into the following groups: pseudo-surgical, blank-control, O2R0(occluded for 2 hours and reperfused for 0 hour), O2R0.5, O2R2, O2R4, O2R24. There were 6 rats in each group. Rats in experimental groups were suffered focal cerebral ischemia/reperfusion through a nylon suture method. After a special processor for tissue manage, the brain were coronal sectioned and stained with H&E, TB, and AG III. The area where dark neurons dwell in (ischemic core) were calculated with image analysis system. The success rate of ischemic model for this experiment is 90%. After being stained with argyrophil III method, normal neurons appear yellow or pale brown, which is hardly distinguished from the pale brown background. The ischemic neuron stained black, and has collapsed body and "corkscrew-like" axon or dentries, which were broken to some extent. The neuropil in the dark neurons dwelt area appears gray or pale black, which is apparently different from the pale brown neighborhood area. The distribution of dark neurons in cortex varies according to different layers, and has a character of columnar form. The dark neurons present as early as 2 hours ischemia without reperfusion with AG III method. AG III stain could selectively display early ischemic neurons, the area dwelt by dark neurons represent early ischemic core. Dark neuron is possibly the irreversibly damaged neuron. Identification of dark neurons could be helpful in the discrimination between early ischemic center and penumbra.

Speciation analysis of inorganic arsenic by magnetic solid phase extraction on-line with inductively coupled mass spectrometry determination.

PubMed

Montoro Leal, P; Vereda Alonso, E; López Guerrero, M M; Cordero, M T Siles; Cano Pavón, J M; García de Torres, A

2018-07-01

Arsenic, one of the main environmental pollutants and potent natural poison, is a chemical element that is spread throughout the Earth's crust. It is well known that the toxicity of arsenic is highly dependent on its chemical forms. Generally, the inorganic species are more toxic than its organics forms, and As(III) is 60 times more toxic than As(V). In environmental waters, arsenic exists predominantly in two chemical forms: As(III) and As(V). In view of these facts, fast, sensitive, accurate and simple analytical methods for the speciation of inorganic arsenic in environmental waters are required. In this work, a new magnetic solid phase extraction with a hydride generation system was coupled on line with inductively coupled plasma mass spectrometry (MSPE-HG-ICP-MS). The new system was based on the retention of As(III) and As(V) in two knotted reactors filled with (Fe 3 O 4 ) magnetic nanoparticles functionalized with [1,5-bis (2-pyridyl) 3-sulfophenylmethylene] thiocarbonohydrazide (PSTH-MNPs). As(III) and total inorganic As were sequentially eluted in different reduction conditions. The concentration of As(V) was obtained by subtracting As(III) from total As. The system runs in a fully automated way and the method has proved to have a wide linear range and to be precise, sensitive and fast. The detection limits found were 2.7 and 3.2 ng/L for As(III) and total As, respectively; with relative standard deviations (RSDs) of 2.5% and 2.7% and a sample throughput of 14.4 h -1 . In order to validate the developed method, several certified reference samples of environmental waters including sea water, were analyzed and the determined values were in good agreement with the certified values. The proposed method was successfully applied to the speciation analysis of inorganic arsenic in well-water and sea water. Copyright © 2018 Elsevier B.V. All rights reserved.

A study of water hardness and the prevalence of hypomagnesaemia and hypocalcaemia in healthy subjects of Surat district (Gujarat).

PubMed

Kanadhia, Kirti C; Ramavataram, Divvi Venkata Subrahmanya Shri; Nilakhe, Shreeyas Prasad Dhanpal; Patel, Swati

2014-01-01

Various sources of drinking water, with varying levels of total hardness, and calcium and magnesium concentrations, are used by populations in different regions. The use of water purifiers can compound the problem of maintaining the desired levels of hardness. An inverse relationship between various conditions, including cardiovascular disease, and hard water has been reported. Until this study, investigation of the hardness of drinking water from different sources, and serum magnesium and calcium in normal subjects from the Surat district, had not been undertaken. This study was performed to assess the concentrations of calcium and magnesium, and total hardness in filtered and non-filtered water and the relationship with serum magnesium and calcium levels in normal subjects consuming such water. Three water samples were collected, at 15-day intervals, from 12 urban and rural areas of Surat; and also 10 different brands of bottled water. Samples were analyzed for total hardness and calcium by complexometric and EDTA methods respectively. Magnesium concentrations were obtained by subtraction of the calcium concentration from total hardness. Serum samples from healthy individuals were analyzed for magnesium and calcium using calmagite and arsenazo methods respectively. The independent t-test was used to establish significance at a level of 95%. A p-value <0.05 was considered significant. Mean total hardness, and calcium and magnesium concentrations in non-filtered, rural tube-well water were much higher than in filtered water from the same area, and the magnesium concentrations were significantly higher (p = 0.038). Filtered urban municipal had lower hardness and concentrations of calcium and magnesium (p = 0.01) compared to corresponding non-filtered water. Significantly lower levels were observed in bottled water compared to rural and urban sources of water. Serum magnesium was significantly lower in the population who were consuming filtered water compared to those drinking non-filtered water (p<0.05). No such difference was observed for serum calcium. Hypomagnesemia correlates with lower magnesium concentrations in drinking water (both rural tube-well and urban municipal waters), which can be attributed to the use of water purifiers. Assuming that a person consumes two liters of drinking water per day, it is estimated that there is an average loss of 160 mg (79%) of magnesium from total waterborne magnesium levels as a result of the filtration of both rural and urban water supplies. Bottled water is too hardness as in calcium and magnesium concentrations.

Method for photochemical reduction of uranyl nitrate by tri-N-butyl phosphate and application of this method to nuclear fuel reprocessing

DOEpatents

De Poorter, Gerald L.; Rofer-De Poorter, Cheryl K.

1978-01-01

Uranyl ion in solution in tri-n-butyl phosphate is readily photochemically reduced to U(IV). The product U(IV) may effectively be used in the Purex process for treating spent nuclear fuels to reduce Pu(IV) to Pu(III). The Pu(III) is readily separated from uranium in solution in the tri-n-butyl phosphate by an aqueous strip.

Small Independent Action Force (SIAF), Vegetation Classification Study

DTIC Science & Technology

1976-03-01

CONTENTS I. INTRODUCTION 8 II. BACKGBCUND and PORPOSE 10 III. METHOD 16 A. EXPERIMENTAL DESIGN 16 B. SUBJECTS .’ 17 C. APPARATUS 17 D. STIMULUS...reliability of subjects will be obtained. 15 III. METHOD A. EXPERIMENTAL DESIGN . The experiment involved a continous stream of stimuli. Phase 1 stimuli...the attribute to be scaled. The subjecr must designate one of the pair as greater. No equality judgments are permitted. In order to obtain data from

Determination of gallium at trace levels using a spectrofluorimetric method in synthetic U-Ga and Ga-As solutions.

PubMed

Kara, Derya; Fisher, Andrew; Foulkes, Mike; Hill, Steve J

2010-01-01

A simple, easy to use and selective spectrofluorimetric method for the determination of trace levels of gallium has been developed. A new Schiff base, N-o-vanillidine-2-amino-p-cresol (OVAC) was synthesized and its fluorescence activity with gallium investigated. Based on this chelation reaction, a spectrofluorimetric method has been developed for the determination of gallium in synthetically prepared Ga-U and Ga-As samples buffered at pH 4.0 using acetic acid-sodium acetate. The chelation reaction between Ga(III) and N-o-vanillidine-2-amino-p-cresol was very fast, requiring only 30min at room temperature to complex completely. The limit of detection (LOD) (3sigma) for Ga(III) was 7.17 nM (0.50 microgL(-1)), determined from the analysis of 11 different solutions of 20 microg L(-1) Ga(III). Copyright 2009 Elsevier B.V. All rights reserved.

Determination of Trace Amounts of Chromium(III) in Water Samples Using Online Flow Injection Catalytic Spectrophotometry

NASA Astrophysics Data System (ADS)

Zhao, Z. X.; Zhang, X. S.

2017-01-01

A new online flow injection spectrophotometric method for the determination of trivalent chromium was developed. This method is based on the property of trivalent chromium to be a catalyst for the oxidation of Indigo Carmine (IC) with potassium periodate and to lose its color in the presence of ethylenediaminetetraacetic acid and sodium tripolyphosphate. It was shown that Tween-20 serves as an additional accelerator of the catalytic oxidation. The linear dynamic range of the determination of Cr(III) was 1-40.0 μg/L, while the limit of detection was 0.05 μg/L. The correlation coefficient r was 0.998, while the relative standard deviation for 5 μg/L of the Cr(III) solution was 3.83%. The feasibility of this method was checked by its application to trivalent chromium determination in real water samples.

On High-Order Upwind Methods for Advection

NASA Technical Reports Server (NTRS)

Huynh, H. T.

2017-01-01

In the fourth installment of the celebrated series of five papers entitled "Towards the ultimate conservative difference scheme", Van Leer (1977) introduced five schemes for advection, the first three are piecewise linear, and the last two, piecewise parabolic. Among the five, scheme I, which is the least accurate, extends with relative ease to systems of equations in multiple dimensions. As a result, it became the most popular and is widely known as the MUSCL scheme (monotone upstream-centered schemes for conservation laws). Schemes III and V have the same accuracy, are the most accurate, and are closely related to current high-order methods. Scheme III uses a piecewise linear approximation that is discontinuous across cells, and can be considered as a precursor of the discontinuous Galerkin methods. Scheme V employs a piecewise quadratic approximation that is, as opposed to the case of scheme III, continuous across cells. This method is the basis for the on-going "active flux scheme" developed by Roe and collaborators. Here, schemes III and V are shown to be equivalent in the sense that they yield identical (reconstructed) solutions, provided the initial condition for scheme III is defined from that of scheme V in a manner dependent on the CFL number. This equivalence is counter intuitive since it is generally believed that piecewise linear and piecewise parabolic methods cannot produce the same solutions due to their different degrees of approximation. The finding also shows a key connection between the approaches of discontinuous and continuous polynomial approximations. In addition to the discussed equivalence, a framework using both projection and interpolation that extends schemes III and V into a single family of high-order schemes is introduced. For these high-order extensions, it is demonstrated via Fourier analysis that schemes with the same number of degrees of freedom ?? per cell, in spite of the different piecewise polynomial degrees, share the same sets of eigenvalues and thus, have the same stability and accuracy. Moreover, these schemes are accurate to order 2??-1, which is higher than the expected order of ??.

Effect of alkali cations on two-dimensional networks of two new quaternary thioarsenates (III) prepared by a facile surfactant-thermal method

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

Yan, Dongming; Hou, Peipei; Liu, Chang

2016-09-15

Two new quaternary thioarsenates(III) NaAg{sub 2}AsS{sub 3}·H{sub 2}O (1) and KAg{sub 2}AsS{sub 3} (2) with high yields have been successfully prepared through a facile surfactant-thermal method. It is interesting that 2 can only be obtained with the aid of ethanediamine (en), which indicates that weak basicity of solvent is beneficial to the growth of 2 compared with 1. Both 1 and 2 feature the similar two-dimensional (2D) layer structures. However, the distortion of the primary honeycomb-like nets in 2 is more severe than that of 1, which demonstrates that Na{sup +} and K{sup +} cations have different structure directing effectsmore » on these two thioarsenates(III). Both experimental and theoretical studies confirm 1 and 2 are semiconductors with band gaps in the visible region. Our success in preparing these two quaternary thioarsenates(III) proves that surfactant-thermal technique is a powerful yet facile synthetic method to explore new complex chalcogenides. - Graphical abstract: Two new quaternary thioarsenates(III) NaAg{sub 2}AsS{sub 3}·H{sub 2}O (1) and KAg{sub 2}AsS{sub 3} (2) with high yields have been successfully prepared through a facile surfactant-thermal method. X-ray single crystal diffraction analyses demonstrate that Na{sup +} and K{sup +} cations have different structure directing effects on these two thioarsenates(III). Both experimental and theoretical studies confirm 1 and 2 are semiconductors with band gaps in the visible region. Display Omitted - Highlights: • NaAg{sub 2}AsS{sub 3}⋅H{sub 2}O (1) and KAg{sub 2}AsS{sub 3} (2) were prepared through surfactant-thermal method. • Crystal structures show Na{sup ±} and K{sup ±} have different structure directing effects. • The weak basicity of solvent is benefit to the growth of 2 compared with 1. • Experimental and theoretical studies confirm 1 and 2 are semiconductors.« less

A chemiluminescence method to detect hydroquinone with water-soluble sulphonato-(salen)manganese(III) complex as catalyst.

PubMed

Zhang, Guangbin; Tang, Yuhai; Sun, Yang; Yu, Hua; Du, Wei; Fu, Qiang

2016-02-01

A water-soluble sulphonato-(salen)manganese(III) complex with excellent catalytic properties was synthesized and demonstrated to greatly enhance the chemiluminescence signal of the hydrogen peroxide - luminol reaction. Coupled with flow-injection technique, a simple and sensitive chemiluminescence method was first developed to detect hydroquinone based on the chemiluminescence system of the hydrogen peroxide-luminol-sulphonato-(salen)manganese(III) complex. Under optimal conditions, the assay exhibited a wide linear range from 0.1 to 10 ng mL(-1) with a detection limit of 0.05 ng mL(-1) for hydroquinone. The method was applied successfully to detect hydroquinone in tap-water and mineral-water, with a sampling frequency of 120 times per hour. The relative standard deviation for determination of hydroquinone was less than 5.6%, and the recoveries ranged from 96.8 to 103.0%. The ultraviolet spectra, chemiluminescence spectra, and the reaction kinetics for the peroxide-luminol-sulphonato-(salen)manganese(III) complex system were employed to study the possible chemiluminescence mechanism. The proposed chemiluminescence analysis technique is rapid and sensitive, with low cost, and could be easily extended and applied to other compounds. Copyright © 2015 John Wiley & Sons, Ltd.

Comparison of Genomic Methods for Differentiating Strains of Enterococcus faecium: Assessment Using Clinical Epidemiologic Data

PubMed Central

Savor, Connie; Pfaller, Michael A.; Kruszynski, Julie A.; Hollis, Richard J.; Noskin, Gary A.; Peterson, Lance R.

1998-01-01

Genomic DNA extracted from 45 vancomycin-resistant Enterococcus faecium (VRE) isolates was cleaved with HindIII and HaeIII and subjected to agarose gel electrophoresis. The ability of this method (restriction endonuclease analysis [REA]) to distinguish strains at the subspecies level was compared with results previously determined by pulsed-field gel electrophoresis (PFGE). Chart reviews were performed to provide a clinical correlation of possible epidemiologic relatedness. A likely clinical association was found for 29 patients as part of two outbreaks. REA found 21 of 21 isolates were the same type in the first outbreak, with PFGE calling 19 strains the same type. In the second outbreak with eight patient isolates, HindIII found six were the same type and two were unique types. HaeIII found three strains were the same type, two strains were a separate type, and three more strains were unique types, while PFGE found three were the same type and five were unique types. No single “ideal” method can be used without clinical epidemiologic investigation, but any of these techniques is helpful in providing focus to infection control practitioners assessing possible outbreaks of nosocomial infection. PMID:9774587

Zincon-modified activated carbon for solid-phase extraction and preconcentration of trace lead and chromium from environmental samples.

PubMed

Li, Zhenhua; Chang, Xijun; Hu, Zheng; Huang, Xinping; Zou, Xiaojun; Wu, Qiong; Nie, Rong

2009-07-15

A new method that utilizes zincon-modified activated carbon (AC-ZCN) as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III) and Pb(II) prior to the measurement by inductively coupled plasma optical emission spectrometry (ICP-OES). The separation/preconcentration conditions of analytes were investigated, including effects of pH, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. At pH 4, the maximum adsorption capacity of Cr(III) and Pb(II) onto the AC-ZCN were 17.9 and 26.7 mg g(-1), respectively. The adsorbed metal ions were quantitatively eluted by 1 mL of 0.1 mol L(-1) HCl. Common coexisting ions did not interfere with the separation. According to the definition of IUPAC, the detection limits (3 sigma) of this method for Cr(III) and Pb(II) were 0.91 and 0.65 ng mL(-1), respectively. The relative standard deviation under optimum condition is less than 3.5% (n=8). The method has been applied for the determination of Cr(III) and Pb(II) in biological materials and water samples with satisfactory results.

Colorimetric sensing of oxalate based on its inhibitory effect on the reaction of Fe (III) with curcumin nanoparticles

NASA Astrophysics Data System (ADS)

Pourreza, Nahid; Lotfizadeh, Neda; Golmohammadi, Hamed

2018-03-01

In this research, a new colorimetric method for the determination of oxalate using curcumin nanoparticles (CURNs) in the presence Fe (III) is introduced. The method is based on the inhibitory effect of oxalate ion on the reaction of (CURNs) with Fe (III) in acidic media. This reaction was monitored by measuring the increase in absorbance of CURNs-Fe3 + complex in the presence of oxalate ion at 427 nm. The effect of different parameters such as the pH of the sample solution, concentration of Fe (III), concentration of CURNs and the reaction time was examined and optimized. Under optimum experimental conditions, the absorption intensity was linear with the concentration of oxalate in the range of 0.15 to 1.70 μg mL- 1. The limit of detection (LOD) was 0.077 μg mL- 1 and the relative standard deviations (RSD) for 8 replicate measurements of 0.40 and 1.05 μg mL- 1 of oxalate were 4.20% and 2.74%, respectively. The developed method was successfully employed to the determination of oxalate in water, food and urine samples with satisfactory results.

One of the possible mechanisms for the inhibition effect of Tb(III) on peroxidase activity in horseradish (Armoracia rusticana) treated with Tb(III).

PubMed

Guo, Shaofen; Cao, Rui; Lu, Aihua; Zhou, Qing; Lu, Tianhong; Ding, Xiaolan; Li, Chaojun; Huang, Xiaohua

2008-05-01

One of the possible mechanisms for the inhibition effect of Tb(III) on peroxidase activity in horseradish (Armoracia rusticana) treated with Tb(III) was investigated using some biophysical and biochemical methods. Firstly, it was found that a large amount of Tb(III) can be distributed on the cell wall, that some Tb(III) can enter into the horseradish cell, indicating that peroxidase was mainly distributed on cell wall, and thus that Tb(III) would interact with horseradish peroxidase (HRP) in the plant. In addition, peroxidase bioactivity was decreased in the presence of Tb(III). Secondly, a new peroxidase-containing Tb(III) complex (Tb-HRP) was obtained from horseradish after treatment with Tb(III); the molecular mass of Tb-HRP is near 44 kDa and the pI is about 8.80. Thirdly, the electrocatalytic activity of Tb-HRP is much lower than that of HRP obtained from horseradish without treatment with Tb(III). The decrease in the activity of Tb-HRP is due to the destruction (unfolding) of the conformation in Tb-HRP. The planarity of the heme active center in the Tb-HRP molecule was increased and the extent of exposure of Fe(III) in heme was decreased, leading to inhibition of the electron transfer. The microstructure change in Tb-HRP might be the result of the inhibition effect of Tb(III) on peroxidase activity in horseradish.

Comparative serum albumin interactions and antitumor effects of Au(III) and Ga(III) ions.

PubMed

Sarioglu, Omer Faruk; Ozdemir, Ayse; Karaboduk, Kuddusi; Tekinay, Turgay

2015-01-01

In the present study, interactions of Au(III) and Ga(III) ions on human serum albumin (HSA) were studied comparatively via spectroscopic and thermal analysis methods: UV-vis absorbance spectroscopy, fluorescence spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and isothermal titration calorimetry (ITC). The potential antitumor effects of these ions were studied on MCF-7 cells via Alamar blue assay. It was found that both Au(III) and Ga(III) ions can interact with HSA, however; Au(III) ions interact with HSA more favorably and with a higher affinity. FT-IR second derivative analysis results demonstrated that, high concentrations of both metal ions led to a considerable decrease in the α-helix content of HSA; while Au(III) led to around 5% of decrease in the α-helix content at 200μM, it was around 1% for Ga(III) at the same concentration. Calorimetric analysis gave the binding kinetics of metal-HSA interactions; while the binding affinity (Ka) of Au(III)-HSA binding was around 3.87×10(5)M(-1), it was around 9.68×10(3)M(-1) for Ga(III)-HSA binding. Spectroscopy studies overall suggest that both metal ions have significant effects on the chemical structure of HSA, including the secondary structure alterations. Antitumor activity studies on MCF7 tumor cell line with both metal ions revealed that, Au(III) ions have a higher antiproliferative activity compared to Ga(III) ions. Copyright © 2014 Elsevier GmbH. All rights reserved.

Rapid and Automated Analytical Methods for Redox Species Based on Potentiometric Flow Injection Analysis Using Potential Buffers

PubMed Central

Ohura, Hiroki; Imato, Toshihiko

2011-01-01

Two analytical methods, which prove the utility of a potentiometric flow injection technique for determining various redox species, based on the use of some redox potential buffers, are reviewed. The first is a potentiometric flow injection method in which a redox couple such as Fe(III)-Fe(II), Fe(CN)6 3−-Fe(CN)(CN)6 4−, and bromide-bromine and a redox electrode or a combined platinum-bromide ion selective electrode are used. The analytical principle and advantages of the method are discussed, and several examples of its application are reported. Another example is a highly sensitive potentiometric flow injection method, in which a large transient potential change due to bromine or chlorine as an intermediate, generated during the reaction of the oxidative species with an Fe(III)-Fe(II) potential buffer containing bromide or chloride, is utilized. The analytical principle and details of the proposed method are described, and examples of several applications are described. The determination of trace amounts of hydrazine, based on the detection of a transient change in potential caused by the reaction with a Ce(IV)-Ce(III) potential buffer, is also described. PMID:21584280

Fe-Mn binary oxide incorporated into diatomite as an adsorbent for arsenite removal: preparation and evaluation.

PubMed

Chang, Fangfang; Qu, Jiuhui; Liu, Huijuan; Liu, Ruiping; Zhao, Xu

2009-10-15

Fe-Mn binary oxide incorporated into diatomite (FMBO-diatomite) was prepared by a simple coating method, and exhibited high oxidation and adsorption ability for arsenite [As(III)]. After being incorporated by Fe-Mn binary oxide, the surface area of diatomite increased 36%, and the pore volume increased five times. The pHzpc of FMBO-diatomite was determined to be 8.1. These characteristics are responsible for the increased As(III) adsorption efficiency. The adsorption equilibria of As(III) on FMBO-diatomite were described well by a Langmuir isotherm model due to the homogeneous distribution of Fe-Mn binary oxide on a diatomite surface. As(III) was oxidized into As(V), and then adsorbed by FMBO-diatomite. The oxidation and adsorption efficiencies for As(III) depended deeply on the pH of solution. When the pH was raised to 8.1, the As(III) adsorption efficiency of FMBO-diatomite was almost equal to the As(III) oxidation efficiency. Silicate and phosphate had negative effects on As(III) adsorption. Also the influence of silicate and phosphate with the pH variation was different.

Investigation of complexes tannic acid and myricetin with Fe(III)

NASA Astrophysics Data System (ADS)

Sungur, Şana; Uzar, Atike

2008-01-01

The pH dependence of the complexes was determined by both potentiometric and spectrophotometric studies. Stability constants and stoichiometries of the formed complexes were determined using slope ratio method. Fe(III) was formed complexes with tannic acid of various stoichiometries, which in the 1:1 molar ratio at pH < 3, in the 2:1 molar ratio at pH 3-7 and in the 4:1 molar ratio at pH > 7. Fe(III) was formed complexes with myricetin in the 1:2 molar ratio at pH 4 and 5 and in the 1:1 molar ratio at pH 6. Stability constant values were found to be 10 5 to 10 17 and 10 5 to 10 9 for Fe(III)-tannic acid complexes and Fe(III)-myricetin complexes. Both tannic acid and myricetin were possessed minimum affinities to Cu(II) and Zn(II). They had less affinity for Al(III) than for Fe(III).

Adsorption, oxidation, and reduction behavior of arsenic in the removal of aqueous As(III) by mesoporous Fe/Al bimetallic particles.

PubMed

Cheng, Zihang; Fu, Fenglian; Dionysiou, Dionysios D; Tang, Bing

2016-06-01

In this study, mesoporous iron/aluminum (Fe/Al) bimetallic particles were synthesized and employed for the removal of aqueous As(III). Scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS), Brunauer-Emmett-Teller (BET) analysis method, Vibrating-sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) were employed to characterize the Fe/Al bimetals before and after reaction with As(III). The physical properties, compositions, and structures of Fe/Al bimetallic particles as well as the As(III) removal mechanism were investigated. The characterization of the bimetallic particles after the reaction has revealed the removal of As(III) is a complex process including surface adsorption and oxidation, and intraparticle reduction. The good As(III) removal capability and stability of the Fe/Al bimetallic particles exhibited its great potential as an effective and environmental friendly agent for As(III) removal from water. Copyright © 2016 Elsevier Ltd. All rights reserved.

Production of a monoclonal antibody and development of an immunoassay for detection of Cr(III) in water samples.

PubMed

Zhou, Y; Li, Y S; Meng, X Y; Zhang, Y Y; Yang, L; Li, Z H; Zhang, J H; Wang, X R; Liu, J Q; Lu, S Y; Ren, H L; Hu, P; Liu, Z S

2013-11-01

In this study we report the production of a monoclonal antibody (Mab) specific for Cr(III)-chelate and the development of a competitive immunoassay for detection of Cr(III) in water samples. In the assay, the complete antigen (Cr(III)-ITCBE-BSA) was used as coating antigen, and Cr(III)-ITCBE as competitor competes with coating antigen to bind with Mab. Using this approach, the spiked water samples with Cr(III) were detected. The linear range of the detection was 0.7-12.4 ng mL(-1). The limit of the detection (LOD) was 0.51 ng mL(-1). The spiked results were also confirmed by ICP-MS, which showed a good correlation (R(2)=0.997) between the two methods. The results indicated that the developed assay was reliable and suitable for the detection of Cr(III) in water samples. Copyright © 2013 Elsevier Ltd. All rights reserved.

Insights into quasar UV spectra using unsupervised clustering analysis

NASA Astrophysics Data System (ADS)

Tammour, A.; Gallagher, S. C.; Daley, M.; Richards, G. T.

2016-06-01

Machine learning techniques can provide powerful tools to detect patterns in multidimensional parameter space. We use K-means - a simple yet powerful unsupervised clustering algorithm which picks out structure in unlabelled data - to study a sample of quasar UV spectra from the Quasar Catalog of the 10th Data Release of the Sloan Digital Sky Survey (SDSS-DR10) of Paris et al. Detecting patterns in large data sets helps us gain insights into the physical conditions and processes giving rise to the observed properties of quasars. We use K-means to find clusters in the parameter space of the equivalent width (EW), the blue- and red-half-width at half-maximum (HWHM) of the Mg II 2800 Å line, the C IV 1549 Å line, and the C III] 1908 Å blend in samples of broad absorption line (BAL) and non-BAL quasars at redshift 1.6-2.1. Using this method, we successfully recover correlations well-known in the UV regime such as the anti-correlation between the EW and blueshift of the C IV emission line and the shape of the ionizing spectra energy distribution (SED) probed by the strength of He II and the Si III]/C III] ratio. We find this to be particularly evident when the properties of C III] are used to find the clusters, while those of Mg II proved to be less strongly correlated with the properties of the other lines in the spectra such as the width of C IV or the Si III]/C III] ratio. We conclude that unsupervised clustering methods (such as K-means) are powerful methods for finding `natural' binning boundaries in multidimensional data sets and discuss caveats and future work.

Chromium(III)-imprinted silica gel for speciation analysis of chromium in environmental water samples with ICP-MS detection.

PubMed

Zhang, Nan; Suleiman, Jibrin Sabo; He, Man; Hu, Bin

2008-04-15

A new chromium(III)-imprinted 3-(2-aminoethylamino) propyltrimethoxysilane (AAPTS)-functionalized silica gel sorbent was synthesized by a surface imprinting technique and was employed as a selective solid-phase extraction material for speciation analysis of chromium in environmental water samples prior to its determination by inductively coupled plasma mass spectrometry (ICP-MS). The prepared Cr(III)-imprinted silica gel shows the selectivity coefficient of more than 700 for Cr(III) in the presence of Mn(II). The static adsorption capacity of the ion-imprinted and non-imprinted sorbent for Cr(III) were 30.5 mg g(-1) and 13.4 mg g(-1). It was also found that Cr(VI) could be adsorbed at low pH by the prepared imprinted silica gel, and this finding makes it feasible to enrich and determine Cr(VI) at low pH without adding reducing reagents. The imprinted silica gel sorbent offered a fast kinetics for the adsorption and desorption of both chromium species. Under the optimized conditions, the detection limits of 4.43 pg mL(-1) and 8.30 pg mL(-1) with the relative standard deviations (R.S.D.s) of 4.44% and 4.41% (C=0.5 ng mL(-1), n=7) for Cr(III) and Cr(VI) were obtained, respectively. The proposed method was successfully applied to the speciation of trace chromium in environmental water samples. To validate the proposed method, two certified reference materials were analyzed and the determined values were in a good agreement with the certified values. The developed method is rapid, selective, sensitive and applicable for the speciation of trace chromium in environmental water samples.

Solid-State Kinetic Investigations of Nonisothermal Reduction of Iron Species Supported on SBA-15

PubMed Central

2017-01-01

Iron oxide catalysts supported on nanostructured silica SBA-15 were synthesized with various iron loadings using two different precursors. Structural characterization of the as-prepared FexOy/SBA-15 samples was performed by nitrogen physisorption, X-ray diffraction, DR-UV-Vis spectroscopy, and Mössbauer spectroscopy. An increasing size of the resulting iron species correlated with an increasing iron loading. Significantly smaller iron species were obtained from (Fe(III), NH4)-citrate precursors compared to Fe(III)-nitrate precursors. Moreover, smaller iron species resulted in a smoother surface of the support material. Temperature-programmed reduction (TPR) of the FexOy/SBA-15 samples with H2 revealed better reducibility of the samples originating from Fe(III)-nitrate precursors. Varying the iron loading led to a change in reduction mechanism. TPR traces were analyzed by model-independent Kissinger method, Ozawa, Flynn, and Wall (OFW) method, and model-dependent Coats-Redfern method. JMAK kinetic analysis afforded a one-dimensional reduction process for the FexOy/SBA-15 samples. The Kissinger method yielded the lowest apparent activation energy for the lowest loaded citrate sample (Ea ≈ 39 kJ/mol). Conversely, the lowest loaded nitrate sample possessed the highest apparent activation energy (Ea ≈ 88 kJ/mol). For samples obtained from Fe(III)-nitrate precursors, Ea decreased with increasing iron loading. Apparent activation energies from model-independent analysis methods agreed well with those from model-dependent methods. Nucleation as rate-determining step in the reduction of the iron oxide species was consistent with the Mampel solid-state reaction model. PMID:29230346

AlGaAs/Si dual-junction tandem solar cells by epitaxial lift-off and print-transfer-assisted direct bonding

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

Xiong, Kanglin; Mi, Hongyi; Chang, Tzu-Hsuan

A novel method is developed to realize a III-V/Si dual-junction photovoltaic cell by combining epitaxial lift-off (ELO) and print-transfer-assisted bonding methods. The adoption of ELO enables III-V wafers to be recycled and reused, which can further lower the cost of III-V/Si photovoltaic panels. For demonstration, high crystal quality, micrometer-thick, GaAs/AlGaAs/GaAs films are lifted off, transferred, and directly bonded onto Si wafer without the use of any adhesive or bonding agents. The bonding interface is optically transparent and conductive both thermally and electrically. Prototype AlGaAs/Si dual-junction tandem solar cells have been fabricated and exhibit decent performance.

AlGaAs/Si dual-junction tandem solar cells by epitaxial lift-off and print-transfer-assisted direct bonding

DOE PAGES

Xiong, Kanglin; Mi, Hongyi; Chang, Tzu-Hsuan; ...

2018-01-04

A novel method is developed to realize a III-V/Si dual-junction photovoltaic cell by combining epitaxial lift-off (ELO) and print-transfer-assisted bonding methods. The adoption of ELO enables III-V wafers to be recycled and reused, which can further lower the cost of III-V/Si photovoltaic panels. For demonstration, high crystal quality, micrometer-thick, GaAs/AlGaAs/GaAs films are lifted off, transferred, and directly bonded onto Si wafer without the use of any adhesive or bonding agents. The bonding interface is optically transparent and conductive both thermally and electrically. Prototype AlGaAs/Si dual-junction tandem solar cells have been fabricated and exhibit decent performance.

Single-source precursors for ternary chalcopyrite materials, and methods of making and using the same

NASA Technical Reports Server (NTRS)

Banger, Kulbinder K. (Inventor); Hepp, Aloysius F. (Inventor); Harris, Jerry D. (Inventor); Jin, Michael Hyun-Chul (Inventor); Castro, Stephanie L. (Inventor)

2006-01-01

A single source precursor for depositing ternary I-III-VI.sub.2 chalcopyrite materials useful as semiconductors. The single source precursor has the I-III-VI.sub.2 stoichiometry built into a single precursor molecular structure which degrades on heating or pyrolysis to yield the desired I-III-VI.sub.2 ternary chalcopyrite. The single source precursors effectively degrade to yield the ternary chalcopyrite at low temperature, e.g. below 500.degree. C., and are useful to deposit thin film ternary chalcopyrite layers via a spray CVD technique. The ternary single source precursors according to the invention can be used to provide nanocrystallite structures useful as quantum dots. A method of making the ternary single source precursors is also provided.

Photochemical and DFT studies on DNA-binding ability and antibacterial activity of lanthanum(III)-phenanthroline complex

NASA Astrophysics Data System (ADS)

Niroomand, Sona; Khorasani-Motlagh, Mozhgan; Noroozifar, Meissam; Jahani, Shohreh; Moodi, Asieh

2017-02-01

The binding of the lanthanum(III) complex containing 1,10-phenanthroline (phen), [La(phen)3Cl3·OH2], to DNA is investigated by absorption and emission methods. This complex shows absorption decreasing in a charge transfer band, and fluorescence decrement when it binds to DNA. Electronic absorption spectroscopy (UV-Vis), fluorescence spectra, iodide quenching experiments, salt effect and viscosity measurements, ethidium bromide (EB) competition test, circular dichroism (CD) spectra as well as variable temperature experiments indicate that the La(III) complex binds to fish salmon (FS) DNA, presumably via groove binding mode. The binding constants (Kb) of the La(III) complex with DNA is (2.55 ± 0.02) × 106 M-1. Furthermore, the binding site size, n, the Stern-Volmer constant KSV and thermodynamic parameters; enthalpy change (ΔH0) and entropy change (ΔS0) and Gibb's free energy (ΔG0), are calculated according to relevant fluorescent data and the Van't Hoff equation. The La(III) complex has been screened for its antibacterial activities by the disc diffusion method. Also, in order to supplement the experimental findings, DFT computation and NBO analysis are carried out.

Chemiluminescence of the reaction system Ce(IV)-non-steroidal anti-inflammatory drugs containing europium(III) ions and its application to the determination of naproxen in pharmaceutical preparations and urine.

PubMed

Kaczmarek, Małgorzata

2011-11-01

The chemiluminescence (CL) of oxidation of non-steroidal anti-inflammatory drugs (NSAIDs) by Ce(IV) ions, was recorded in the presence and absence europium(III) ions, in solution of pH ~ 4 of solution. Kinetic curves and CL emission spectra of the all studied systems were discussed. CL of measurable intensity was observed in the Ce(IV)-NP-Eu(III) reaction system only in acidic solutions. The CL spectrum rcegistered for this system shows emission bands, typical of Eu(III) ions, with maximum at λ ~ 600 nm. The chemiluminescent method, based on Eu(III) emission in reaction system of NP-Ce(IV)-Eu(III) in acid solution was therefore used for the determination of naproxen in mixture of non-steroidal anti-inflammatory drugs.

NMR and TRLFS studies of Ln(iii) and An(iii) C5-BPP complexes.

PubMed

Adam, Christian; Beele, Björn B; Geist, Andreas; Müllich, Udo; Kaden, Peter; Panak, Petra J

2015-02-01

C5-BPP is a highly efficient N-donor ligand for the separation of trivalent actinides, An(iii), from trivalent lanthanides, Ln(iii). The molecular origin of the selectivity of C5-BPP and many other N-donor ligands of the BTP-type is still not entirely understood. We present here the first NMR studies on C5-BPP Ln(iii) and An(iii) complexes. C5-BPP is synthesized with 10% 15 N labeling and characterized by NMR and LIFDI-MS methods. 15 N NMR spectroscopy gives a detailed insight into the bonding of C5-BPP with lanthanides and Am(iii) as a representative for trivalent actinide cations, revealing significant differences in 15 N chemical shift for coordinating nitrogen atoms compared to Ln(iii) complexes. The temperature dependence of NMR chemical shifts observed for the Am(iii) complex indicates a weak paramagnetism. This as well as the observed large chemical shift for coordinating nitrogen atoms show that metal-ligand bonding in Am(C5-BPP) 3 has a larger share of covalence than in lanthanide complexes, confirming earlier studies. The Am(C5-BPP) 3 NMR sample is furthermore spiked with Cm(iii) and characterized by time-resolved laser fluorescence spectroscopy (TRLFS), yielding important information on the speciation of trace amounts of minor complex species.

Measuring “Free” Iron Levels in Caenorhabditis Elegans Using Low-Temperature Fe(III) Electron Paramagnetic Resonance Spectroscopy

PubMed Central

Pate, Kira T.; Rangel, Natalie A.; Fraser, Brian; Clement, Matthew H. S.; Srinivasan, Chandra

2007-01-01

Oxidative stress, caused by free radicals within the body, has been associated with the process of aging and many human diseases. As free radicals, in particular superoxide, are difficult to measure, an alternative indirect method for measuring oxidative stress levels has been successfully used in E. coli and yeast. This method is based on a proposed connection between elevated superoxide levels and release of iron from solvent exposed [4Fe-4S] enzyme clusters, which eventually leads to an increase in hydroxyl radical production. In past studies using bacteria and yeast, a positive correlation was found between superoxide production or oxidative stress due to superoxide within the organism and EPR (electron paramagnetic resonance) detectable “free” iron levels. In the present study, we have developed a reliable and an efficient method for measuring “free” iron levels in C. elegans using low temperature Fe(III) EPR at g = 4.3. This method utilizes synchronized worm cultures grown on plates, which are homogenized and treated with desferrioxamine, an Fe(III) chelator, prior to packing the EPR tube. Homogenization was found not to alter “free” iron levels, while desferrioxamine treatment significantly raised these levels, indicating presence of both Fe(II) and Fe(III) in the “free” iron pool. The correlation between free radical levels and the observed “free” iron levels was examined by using heat stress and paraquat treatment. The intensity of the Fe(III) EPR signal and thus, the concentration of the “free” iron pool, varied with the treatments that altered radical levels without changing the total iron levels. This study provides the groundwork needed to uncover the correlation between oxidative stress, “free” iron levels, and longevity in C. elegans. PMID:17010298

Synthesis, characterization and trivalent arsenic sorption potential of Ce-Al nanostructured mixed oxide

NASA Astrophysics Data System (ADS)

Bhattacharya, S.; Gupta, K.; Ghosh, U. C.

2017-04-01

Arsenic contamination in the ground water has serious health consequences in many parts of the world. The surface sorption method for arsenic mitigation has been widely investigated due to its simple method, inexpensive operation, highly efficient and low content of by-products. In the present study, nanostructured hydrated cerium aluminum oxide (NHCAO) was synthesized and characterized and its arsenic (III) sorption behavior from the aqueous solution was studied. The material was characterized in SEM, FE-SEM, TEM, AFM, XRD, and FT-IR. Batch method was used for the kinetics of As (III) sorption on nanoparticles at 303 (± 1.6) K and at pH 7.0 (± 0.2). The experiments on isotherm subject were performed individually at 288K, 303K, 318K temperatures at pH 7.0 (± 0.2) using the batch sorption method. In the kinetics study of arsenic (III) sorption, the sorption percentage was observed to remain nearly unchanged up to pH 9.0, thereafter only slight reduction in sorption percentage. The equilibrium sorption results were tested using the models of Langmuir and the Freundlich isotherm. The Langmuir model is the most fitted model for the sorption reaction. NHCAO was highly efficient in As(III) removal out of the water in the extensive range of pH and could be used for arsenic removal from contaminated water.

Preparation of microspheric Fe(III)-ion imprinted polymer for selective solid phase extraction

NASA Astrophysics Data System (ADS)

Ara, Behisht; Muhammad, Mian; Salman, Muhammad; Ahmad, Raees; Islam, Noor; Zia, Tanveer ul Haq

2018-03-01

In this research work, an Fe(III)-IIP was prepared using methacrylic acid as monomer, divinylbenzene as cross-linker, azobisisobutyronitrile as initiator. The ion imprinted polymer was functionalized with Fe(III)8-hydroxy quinolone complex under thermal conditions by copolymerization with the monomer and the cross-linker. The prepared Fe(III)-ion imprinted polymer (IIP) and non-ion imprinted polymer (Non-IIP) were characterized with fourier transform-infrared spectroscopy, scanning electron microscopic analysis and thermal gravimetric analysis. The polymer showed a good stability to thermal analysis up to a temperature of 500 °C. The size of the polymer obtained was 1 µm, large enough to be filtered easily. At pH 2.5 more affinity was observed with ion imprinted polymer in comparison to non-ion imprinted polymer. For the kinetic study, the most linear and rhythmical relation were seen in pseudo second order. The maximum sorption capacity of Fe(III) ions on Fe(III)-IIP and non-IIP was 170 and 30.0 µmolg-1, respectively. The relative selectivity factor (αr) values of Fe(III)/Fe(II), Fe(III)/Al(III) and Fe(III)/Cr(III) were 151.0, 84.6 and 91.9, respectively. The preconcentration factor was found to be 240. The developed method was successfully applied to the determination of trace Fe in the drinking water.

Characterization of a high-spin non-heme Fe(III)-OOH intermediate and its quantitative conversion to an Fe(IV)═O complex.

PubMed

Li, Feifei; Meier, Katlyn K; Cranswick, Matthew A; Chakrabarti, Mrinmoy; Van Heuvelen, Katherine M; Münck, Eckard; Que, Lawrence

2011-05-18

We have generated a high-spin Fe(III)-OOH complex supported by tetramethylcyclam via protonation of its conjugate base and characterized it in detail using various spectroscopic methods. This Fe(III)-OOH species can be converted quantitatively to an Fe(IV)═O complex via O-O bond cleavage; this is the first example of such a conversion. This conversion is promoted by two factors: the strong Fe(III)-OOH bond, which inhibits Fe-O bond lysis, and the addition of protons, which facilitates O-O bond cleavage. This example provides a synthetic precedent for how O-O bond cleavage of high-spin Fe(III)-peroxo intermediates of non-heme iron enzymes may be promoted. © 2011 American Chemical Society

A fluorescence microplate screen assay for the detection of neurite outgrowth and neurotoxicity using an antibody against βIII-tubulin.

PubMed

Popova, Dina; Jacobsson, Stig O P

2014-04-01

The majority of environmental and commercial chemicals have not been evaluated for their potential to cause neurotoxicity. We have investigated if neuron specific anti-βIII-tubulin antibodies are useful in a microplate assay of neurite outgrowth of retinoic acid-induced neurons from mouse P19 embryonal carcinoma cells. By incubating the P19-derived neurons with the primary anti-βIII-tubulin antibody and a secondary Alexa Fluor 488-conjugated antibody, followed by measuring the fluorescence in a microplate reader, a time-dependent increase in anti-βIII-tubulin immunofluorescence was observed. The relative fluorescence units increased by 4.3-fold from 2 to 10 days in culture. The results corresponded well with those obtained by semi-automatic tracing of neurites in fluorescence microscopy images of βIII-tubulin-labeled neurons. The sensitivity of the neurite outgrowth assay using a microplate reader to detect neurotoxicity produced by nocodazole, methyl mercury chloride and okadaic acid was significantly higher than for a cell viability assay measuring intracellular fluorescence of calcein-AM. The microplate-based method to measure toxicity targeting neurites using anti-βIII-tubulin antibodies is however less sensitive than the extracellular lactate dehydrogenase activity assay to detect general cytotoxicity produced by high concentrations of clomipramine, or glutamate-induced excitotoxicity. In conclusion, the fluorescence microplate assay for the detection of neurite outgrowth by measuring changes in βIII-tubulin immunoreactivity is a rapid and sensitive method to assess chemical- or toxin-induced neurite toxicity. Copyright © 2013 Elsevier Ltd. All rights reserved.

UV and visible activation of Cr(III)-doped TiO2 catalyst prepared by a microwave-assisted sol-gel method during MCPA degradation.

PubMed

Mendiola-Alvarez, S Y; Guzmán-Mar, J L; Turnes-Palomino, G; Maya-Alejandro, F; Hernández-Ramírez, A; Hinojosa-Reyes, L

2017-05-01

Photocatalytic degradation of 4-chloro-2-methylphenoxyacetic acid (MCPA) in aqueous solution using Cr(III)-doped TiO 2 under UV and visible light was investigated. The semiconductor material was synthesized by a microwave-assisted sol-gel method with Cr(III) doping contents of 0.02, 0.04, and 0.06 wt%. The catalyst was characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), nitrogen physisorption, UV-Vis diffuse reflectance spectroscopy (DRS), and atomic absorption spectroscopy (AAS). The photocatalytic activity for the photodegradation of MCPA was followed by reversed-phase high-performance liquid chromatography (HPLC) and total organic carbon (TOC) analysis. The intermediates formed during degradation were identified using gas chromatography-mass spectrometry (GC-MS). Chloride ion evolution was measured by ion chromatography. Characterization results showed that Cr(III)-doped TiO 2 materials possessed a small crystalline size, high surface area, and mesoporous structure. UV-Vis DRS showed enhanced absorption in the visible region as a function of the Cr(III) concentration. The Cr(III)-doped TiO 2 catalyst with 0.04 wt% of Cr(III) was more active than bare TiO 2 for the degradation of MCPA under both UV and visible light. The intermediates identified during MCPA degradation were 4-chloro-2-methylphenol (CMP), 2-(4-hydroxy-2-methylphenoxy) acetic acid (HMPA), and 2-hydroxybuta-1,3-diene-1,4-diyl-bis (oxy)dimethanol (HBDM); the formation of these intermediates depended on the radiation source.

OXIDATION OF AS(III) BY AERATION AND STORAGE

EPA Science Inventory

A study of the effects of aeration and storage on the oxidation of arsenic(III) was undertaken at three utilities in the US to establish the engineering significance of aeration as a potential pre-treatment method for arsenic removal. The results of this study clearly establish t...

Lateral electrochemical etching of III-nitride materials for microfabrication

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

Han, Jung

Conductivity-selective lateral etching of III-nitride materials is described. Methods and structures for making vertical cavity surface emitting lasers with distributed Bragg reflectors via electrochemical etching are described. Layer-selective, lateral electrochemical etching of multi-layer stacks is employed to form semiconductor/air DBR structures adjacent active multiple quantum well regions of the lasers. The electrochemical etching techniques are suitable for high-volume production of lasers and other III-nitride devices, such as lasers, HEMT transistors, power transistors, MEMs structures, and LEDs.

Low loss, high and low index contrast waveguides in semiconductors

DOEpatents

Bond, Tiziana [Livermore, CA; Cole, Garrett [Berkeley, CA; Goddard, Lynford [Champaign, IL; Kallman, Jeff [Pleasanton, CA

2011-08-09

A system in one general embodiment includes a waveguide structure comprising a core of an alloy of Group III-V materials surrounded by an oxide (which may include one or more Group III-V metals), wherein an interface of the oxide and core is characterized by oxidation of the alloy for defining the core. A method in one general approach includes oxidizing a waveguide structure comprising an alloy of Group III-V materials for forming a core of the alloy surrounded by an oxide.

Method for making graded I-III-VI.sub.2 semiconductors and solar cell obtained thereby

DOEpatents

Devaney, Walter E.

1987-08-04

Improved cell photovoltaic conversion efficiencies are obtained by the simultaneous elemental reactive evaporation process of Mickelsen and Chen for making semiconductors by closer control of the evaporation rates and substrate temperature during formation of the near contact, bulk, and near junction regions of a graded I-III-VI.sub.2, thin film, semiconductor, such as CuInSe.sub.2 /(Zn,Cd)S or another I-III-VI.sub.2 /II-VI heterojunction.

46 CFR 160.077-5 - Incorporation by reference.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., Breaking of Woven Cloth; Grab Method. (ii) Method 5132, Strength of Cloth, Tearing; Falling-Pendulum Method. (iii) Method 5134, Strength of Cloth, Tearing; Tongue Method. (iv) Method 5804.1, Weathering Resistance of Cloth; Accelerated Weathering Method. (v) Method 5762, Mildew Resistance of Textile Materials...

46 CFR 160.077-5 - Incorporation by reference.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., Breaking of Woven Cloth; Grab Method. (ii) Method 5132, Strength of Cloth, Tearing; Falling-Pendulum Method. (iii) Method 5134, Strength of Cloth, Tearing; Tongue Method. (iv) Method 5804.1, Weathering Resistance of Cloth; Accelerated Weathering Method. (v) Method 5762, Mildew Resistance of Textile Materials...

Speciation of chromium using reversed phase-high performance liquid chromatography coupled to different spectrometric detection methods

NASA Astrophysics Data System (ADS)

Andrle, C. M.; Jakubowski, N.; Broekaert, J. A. C.

1997-02-01

Speciation of Cr(III) and Cr(VI) based on the formation of different complexes with ammonium-pyrrolidinedithioate (APDC) in a continuous flow technique and their preconcentration using solid phase extraction (SPE) have been elaborated and applied to the analysis of waste waters from the galvanic industry. The Cr complexes were separated and determined using reversed phase-high performance liquid chromatography (RP-HPLC) coupled to different detection methods, namely UV-detection, graphite furnace-atomic absorption spectrometry (GF-AAS) and inductively coupled plasma mass spectrometry with hydraulic high pressure nebulization (HHPN/ICP-MS). After optimization the detection limits for Cr(III) and Cr(VI) of all methods are at the μg 1 -1 level and the precision in terms of RSD is 5% ( cCr = 100 μg 1 -1, N = 10). The procedure was applied to the determination of Cr(III) and Cr(VI) at the μg 1 -1 level in galvanic waste waters, and its accuracy was approved by comparing the results with those of independent methods.

Utility of NBD-Cl for the spectrophotometric determination of some skeletal muscle relaxant and antihistaminic drugs

NASA Astrophysics Data System (ADS)

Saleh, Hanaa M.; EL-Henawee, Magda M.; Ragab, Gamal H.; El-Hay, Soad S. Abd

2007-08-01

A simple, accurate, precise and sensitive colorimetric method for the determination of some skeletal muscle relaxant drugs, namely orphenadrine citrate ( I), baclofen ( II), antihistaminic drugs as acrivastine ( III) and fexofenadine hydrochloride ( IV) is described. This method is based on the formation of charge transfer complex with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) in non-aqueous medium. The orange color products were measured at 472, 465, 475 and 469 nm for drugs I, II, III and IV, respectively. The optimization of various experimental conditions was described. Beer's Law was obeyed in the range (2.5-17.5), (5-70), (2.5-25) and (10-50) μg/ml for drugs I, II, III and IV, respectively. The molar absorptivity ( ɛ), sandell sensitivity, detection (LOD) and quantitation limits (LOQ) are calculated. The procedure was favorably applied for determination of certain pharmaceutical dosage forms containing the studied drugs. The obtained results were compared with the official and reported methods. There were no significant differences between proposed, reported and the official methods.

Louisiana SIP: LAC 33:III Ch 61 Subchap A, §6121 to § 6131--Method 43 - Capture Efficiency Test Procedures; SIP effective 1994-06-06 (LAc60) to to 2011-08-03 (LAd34 - Moved to Chap 21 Subchap N §§ 2155-2160 and revised)

EPA Pesticide Factsheets

Louisiana SIP: LAC 33:III Ch 61 Subchap A, §6121 to § 6131--Method 43 - Capture Efficiency Test Procedures; SIP effective 1994-06-06 (LAc60) to to 2011-08-03 (LAd34 - Moved to Chap 21 Subchap N §§ 2155-2160 and revised)

Louisiana SIP: LAC 33:III Ch. 7 - Table 2 - Ambient Air--Methods of Contaminant Measurements; SIP effective 1989-05-08 (LAc49) and 1989-08-14 (LAc50) to 2011-08-03 (LAd34 - Moved to Section 711 and revised [adds PM-2.5])

EPA Pesticide Factsheets

Louisiana SIP: LAC 33:III Ch. 7 - Table 2 - Ambient Air--Methods of Contaminant Measurements; SIP effective 1989-05-08 (LAc49) and 1989-08-14 (LAc50) to 2011-08-03 (LAd34 - Moved to Section 711 and revised [adds PM-2.5])

Development of magnetic graphene oxide adsorbent for the removal and preconcentration of As(III) and As(V) species from environmental water samples.

PubMed

Rashidi Nodeh, Hamid; Wan Ibrahim, Wan Aini; Ali, Imran; Sanagi, Mohd Marsin

2016-05-01

New-generation adsorbent, Fe3O4@SiO2/GO, was developed by modification of graphene oxide (GO) with silica-coated (SiO2) magnetic nanoparticles (Fe3O4). The synthesized adsorbent was characterized using Fourier transform infrared spectroscopy, X-ray diffractometry, energy-dispersive X-ray spectroscopy, and field emission scanning electron microscopy. The developed adsorbent was used for the removal and simultaneous preconcentration of As(III) and As(V) from environmental waters prior to ICP-MS analysis. Fe3O4@SiO2/GO provided high adsorption capacities, i.e., 7.51 and 11.46 mg g(-1) for As(III) and As(V), respectively, at pH 4.0. Adsorption isotherm, kinetic, and thermodynamic were investigated for As(III) and As(V) adsorption. Preconcentration of As(III) and As(V) were studied using magnetic solid-phase extraction (MSPE) method at pH 9.0 as the adsorbent showed selective adsorption for As(III) only in pH range 7-10. MSPE using Fe3O4@SiO2/GO was developed with good linearities (0.05-2.0 ng mL(-1)) and high coefficient of determination (R (2) = 0.9992 and 0.9985) for As(III) and As(V), respectively. The limits of detection (LODs) (3× SD/m, n = 3) obtained were 7.9 pg mL(-1) for As(III) and 28.0 pg mL(-1) for As(V). The LOD obtained is 357-1265× lower than the WHO maximum permissible limit of 10.0 ng mL(-1). The developed MSPE method showed good relative recoveries (72.55-109.71 %) and good RSDs (0.1-4.3 %, n = 3) for spring water, lake, river, and tap water samples. The new-generation adsorbent can be used for the removal and simultaneous preconcentration of As(III) and As(V) from water samples successfully. The adsorbent removal for As(III) is better than As(V).

Reply to the comment by B. Ghobadipour and B. Mojarradi "M. Abedi, S.A. Torabi, G.-H. Norouzi and M. Hamzeh; ELECTRE III: A knowledge-driven method for integration of geophysical data with geological and geochemical data in mineral prospectivity mapping"

NASA Astrophysics Data System (ADS)

Abedi, Maysam

2015-06-01

This reply discusses the results of two previously developed approaches in mineral prospectivity/potential mapping (MPM), i.e., ELECTRE III and PROMETHEE II as well-known methods in multi-criteria decision-making (MCDM) problems. Various geo-data sets are integrated to prepare MPM in which generated maps have acceptable matching with the drilled boreholes. Equal performance of the applied methods is indicated in the studied case. Complementary information of these methods is also provided in order to help interested readers to implement them in MPM process.

Selection of Thermal Worst-Case Orbits via Modified Efficient Global Optimization

NASA Technical Reports Server (NTRS)

Moeller, Timothy M.; Wilhite, Alan W.; Liles, Kaitlin A.

2014-01-01

Efficient Global Optimization (EGO) was used to select orbits with worst-case hot and cold thermal environments for the Stratospheric Aerosol and Gas Experiment (SAGE) III. The SAGE III system thermal model changed substantially since the previous selection of worst-case orbits (which did not use the EGO method), so the selections were revised to ensure the worst cases are being captured. The EGO method consists of first conducting an initial set of parametric runs, generated with a space-filling Design of Experiments (DoE) method, then fitting a surrogate model to the data and searching for points of maximum Expected Improvement (EI) to conduct additional runs. The general EGO method was modified by using a multi-start optimizer to identify multiple new test points at each iteration. This modification facilitates parallel computing and decreases the burden of user interaction when the optimizer code is not integrated with the model. Thermal worst-case orbits for SAGE III were successfully identified and shown by direct comparison to be more severe than those identified in the previous selection. The EGO method is a useful tool for this application and can result in computational savings if the initial Design of Experiments (DoE) is selected appropriately.

40 CFR 86.001-28 - Compliance with emission standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

...)(iii) of this section rounded to two significant figures in accordance with the Rounding-Off Method specified in ASTM E29-90, Standard Practice for Using Significant Digits in Test Data to Determine... adjusted emission value of paragraph (b)(8)(iii) of this section rounded to two significant figures in...

40 CFR 86.001-28 - Compliance with emission standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

...)(iii) of this section rounded to two significant figures in accordance with the Rounding-Off Method specified in ASTM E29-90, Standard Practice for Using Significant Digits in Test Data to Determine... adjusted emission value of paragraph (b)(8)(iii) of this section rounded to two significant figures in...

40 CFR 86.001-28 - Compliance with emission standards.

Code of Federal Regulations, 2013 CFR

2013-07-01

...)(iii) of this section rounded to two significant figures in accordance with the Rounding-Off Method specified in ASTM E29-90, Standard Practice for Using Significant Digits in Test Data to Determine... adjusted emission value of paragraph (b)(8)(iii) of this section rounded to two significant figures in...

78 FR 18325 - Defense Transportation Regulation, Part IV

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-26

... received in connection with the Defense Personal Property Program (DP3) Phase III Direct Procurement Method... at http://www.transcom.mil/dtr/part-iv/phaseiii.cfm (DPM SECTION). All identified changes will be... Defense Personal Property System (DPS) Phase III programming projected for FY17. FOR FURTHER INFORMATION...

Teaching Spoken Discourse Markers Explicitly: A Comparison of III and PPP

ERIC Educational Resources Information Center

Jones, Christian; Carter, Ronald

2014-01-01

This article reports on mixed methods classroom research carried out at a British university. The study investigates the effectiveness of two different explicit teaching frameworks, Illustration--Interaction--Induction (III) and Present--Practice--Produce (PPP) used to teach the same spoken discourse markers (DMs) to two different groups of…

SEPARATION OF TOXICOLOGICALLY RELEVANT ARSENICALS IN URINE USING A NEW SOLID PHASE EXTRACTION TECHNIQUE

EPA Science Inventory

Abstract - Metabolism and toxicity of arsenicals are critically influenced by the oxidation state of As. In human urine, inorganic and methylated arsenicals contain both As(III) and As(V). Because As(III) is easily oxidized, a method is needed to preserve the native oxidation sta...

Online spectrophotometric determination of Fe(II) and Fe(III) by flow injection combined with low pressure ion chromatography

NASA Astrophysics Data System (ADS)

Chen, Shujuan; Li, Nan; Zhang, Xinshen; Yang, Dongjing; Jiang, Heimei

2015-03-01

A simple and new low pressure ion chromatography combined with flow injection spectrophotometric procedure for determining Fe(II) and Fe(III) was established. It is based on the selective adsorption of low pressure ion chromatography column to Fe(II) and Fe(III), the online reduction reaction of Fe(III) and the reaction of Fe(II) in sodium acetate with phenanthroline, resulting in an intense orange complex with a suitable absorption at 515 nm. Various chemical (such as the concentration of colour reagent, eluant and reductive agent) and instrumental parameters (reaction coil length, reductive coil length and wavelength) were studied and were optimized. Under the optimum conditions calibration graph of Fe(II)/Fe(III) was linear in the Fe(II)/Fe(III) range of 0.040-1.0 mg/L. The detection limit of Fe(III) and Fe(II) was respectively 3.09 and 1.55 μg/L, the relative standard deviation (n = 10) of Fe(II) and Fe(III) 1.89% and 1.90% for 0.5 mg/L of Fe(II) and Fe(III) respectively. About 2.5 samples in 1 h can be analyzed. The interfering effects of various chemical species were studied. The method was successfully applied in the determination of water samples.

Head and Neck Squamous Cell Carcinomas Do Not Express EGFRvIII

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

Melchers, Lieuwe J., E-mail: l.j.melchers@umcg.nl; Department of Pathology, University Medical Center Groningen, University of Groningen, Groningen; Clausen, Martijn J.A.M.

2014-10-01

Purpose: To assess the prevalence of EGFRvIII, a specific variant of EGFR (epidermal growth factor receptor), in 3 well-defined cohorts of head and neck squamous cell carcinoma (HNSCC). Methods and Materials: Immunohistochemistry for the specific detection of EGFRvIII using the L8A4 antibody was optimized on formalin-fixed, paraffin-embedded tissue using glioblastoma tissue. It was compared with EGFR and EGFRvIII RNA expression using a specific reverse transcription–polymerase chain reaction also optimized for formalin-fixed, paraffin-embedded tissue. Tissue microarrays including 531 HNSCCs of various stages with complete clinicopathologic and follow-up data were tested for the presence of EGFRvIII. Results: None of the 531 casesmore » showed EGFRvIII protein expression. Using an immunohistochemistry protocol reported by others revealed cytoplasmic staining in 8% of cases. Reverse transcription–polymerase chain reaction for the EGFRvIII transcript of the 28 highest cytoplasmic staining cases, as well as 69 negative cases, did not show expression in any of the tested cases, suggesting aspecific staining by a nonoptimal protocol. Conclusions: The EGFRvIII mutation is not present in HNSCC. Therefore, EGFRvIII does not influence treatment response in HNSCC and is not a usable clinical prognostic marker.« less

A simple and sensitive fluorimetric aptasensor for the ultrasensitive detection of arsenic(III) based on cysteamine stabilized CdTe/ZnS quantum dots aggregation.

PubMed

Ensafi, Ali A; Kazemifard, N; Rezaei, B

2016-03-15

A new approach for developing a fluorimetric aptasensor has been described and applied for determination of a highly toxic cation, As(III). In this method an aptamer was used to aggregate cationic cysteamine-stabilized CdTe/ZnS core/shell quantum dots, as a result fluorescence quenching was accrued. In the presence of As(III), the aptamer and As(III) make a complex, which prevents aggregation of the quantum dots. Thus, the fluorescence intensity of the quantum dots was enhanced upon the de-aggregation, which depends on the concentration of As(III). The fluorimetric assay has a very low detection limit of 1.3 pmolL(-1) As(III) with a dynamic range of 1.0 × 10(-11) to 1.0 × 10(-6) molL(-1). The interference effect of a wide variety of cations and anions was investigated, and the obtained results confirm high selectivity of the aptasensor for As(III) detection. The present assay was successfully applied for the determination of As(III) in several water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2016-01-01

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

Efficient artificial mineralization route to decontaminate Arsenic(III) polluted water - the Tooeleite Way

NASA Astrophysics Data System (ADS)

Malakar, Arindam; Das, Bidisa; Islam, Samirul; Meneghini, Carlo; de Giudici, Giovanni; Merlini, Marco; Kolen'Ko, Yury V.; Iadecola, Antonella; Aquilanti, Giuliana; Acharya, Somobrata; Ray, Sugata

2016-05-01

Increasing exposure to arsenic (As) contaminated ground water is a great threat to humanity. Suitable technology for As immobilization and removal from water, especially for As(III) than As(V), is not available yet. However, it is known that As(III) is more toxic than As(V) and most groundwater aquifers, particularly the Gangetic basin in India, is alarmingly contaminated with it. In search of a viable solution here, we took a cue from the natural mineralization of Tooeleite, a mineral containing Fe(III) and As(III)ions, grown under acidic condition, in presence of SO42- ions. Complying to this natural process, we could grow and separate Tooeleite-like templates from Fe(III) and As(III) containing water at overall circumneutral pH and in absence of SO42- ions by using highly polar Zn-only ends of wurtzite ZnS nanorods as insoluble nano-acidic-surfaces. The central idea here is to exploit these insoluble nano-acidic-surfaces (called as INAS in the manuscript) as nucleation centres for Tooeleite growth while keeping the overall pH of the aqueous media neutral. Therefore, we propose a novel method of artificial mineralization of As(III) by mimicking a natural process at nanoscale.

Method development for the determination of arsenic by sequential injection/anodic stripping voltammetry using long-lasting gold-modified screen-printed carbon electrode.

PubMed

Punrat, Eakkasit; Chuanuwatanakul, Suchada; Kaneta, Takashi; Motomizu, Shoji; Chailapakul, Orawon

2013-11-15

An automated method has been developed for determining the concentration of inorganic arsenic. The technique uses sequential injection/anodic stripping voltammetry with a long-lasting gold-modified screen-printed carbon electrode. The long-lasting gold electrode was electrochemically deposited onto a screen-printed carbon electrode at a potential of -0.5 V vs. Ag/AgCl in a supporting electrolyte solution of 1M hydrochloric acid. Under optimal conditions and the applied potentials, the electrode demonstrated that it can be used for a long time without a renewal process. The linear range for the determination of arsenic(III) was 1-100 μg L(-1), and the limit of detection (LOD) in standard solutions was as low as 0.03 μg L(-1) for a deposition time of 120 s and sample volume of 1 mL. This method was used to determine the concentration of arsenic(III) in water samples with satisfactory results. The LOD in real samples was found to be 0.5 μg L(-1). In addition, speciation between arsenic(III) and arsenic(V) has been achieved with the proposed method using deposition potentials of -0.5 V and -1.5 V for the determination of the arsenic(III) concentration and the total arsenic concentration, respectively; the results were acceptable. The proposed method is an automated system that offers a less expensive alternative for determining trace amounts of inorganic arsenic. © 2013 Elsevier B.V. All rights reserved.

Application of High-Resolution Magic-Angle Spinning NMR Spectroscopy to Define the Cell Uptake of MRI Contrast Agents

NASA Astrophysics Data System (ADS)

Calabi, Luisella; Alfieri, Goffredo; Biondi, Luca; De Miranda, Mario; Paleari, Lino; Ghelli, Stefano

2002-06-01

A new method, based on proton high-resolution magic-angle spinning ( 1H HR-MAS) NMR spectroscopy, has been employed to study the cell uptake of magnetic resonance imaging contrast agents (MRI-CAs). The method was tested on human red blood cells (HRBC) and white blood cells (HWBC) by using three gadolinium complexes, widely used in diagnostics, Gd-BOPTA, Gd-DTPA, and Gd-DOTA, and the analogous complexes obtained by replacing Gd(III) with Dy(III), Nd(III), and Tb(III) (i.e., complexes isostructural to the ones of gadolinium but acting as shift agents). The method is based on the evaluation of the magnetic effects, line broadening, or induced lanthanide shift (LIS) caused by these complexes on NMR signals of intra- and extracellular water. Since magnetic effects are directly linked to permeability, this method is direct. In all the tests, these magnetic effects were detected for the extracellular water signal only, providing a direct proof that these complexes are not able to cross the cell membrane. Line broadening effects (i.e., the use of gadolinium complexes) only allow qualitative evaluations. On the contrary, LIS effects can be measured with high precision and they can be related to the concentration of the paramagnetic species in the cellular compartments. This is possible because the HR-MAS technique provides the complete elimination of bulk magnetic susceptibility (BMS) shift and the differentiation of extra- and intracellular water signals. Thus with this method, the rapid quantification of the MRI-CA amount inside and outside the cells is actually feasible.

Strain field determination in III-V heteroepitaxy coupling finite elements with experimental and theoretical techniques at the nanoscale

NASA Astrophysics Data System (ADS)

Florini, Nikoletta; Dimitrakopulos, George P.; Kioseoglou, Joseph; Pelekanos, Nikos T.; Kehagias, Thomas

2017-04-01

We are briefly reviewing the current status of elastic strain field determination in III-V heteroepitaxial nanostructures, linking finite elements (FE) calculations with quantitative nanoscale imaging and atomistic calculation techniques. III-V semiconductor nanostructure systems of various dimensions are evaluated in terms of their importance in photonic and microelectronic devices. As elastic strain distribution inside nano-heterostructures has a significant impact on the alloy composition, and thus their electronic properties, it is important to accurately map its components both at the interface plane and along the growth direction. Therefore, we focus on the determination of the stress-strain fields in III-V heteroepitaxial nanostructures by experimental and theoretical methods with emphasis on the numerical FE method by means of anisotropic continuum elasticity (CE) approximation. Subsequently, we present our contribution to the field by coupling FE simulations on InAs quantum dots (QDs) grown on (211)B GaAs substrate, either uncapped or buried, and GaAs/AlGaAs core-shell nanowires (NWs) grown on (111) Si, with quantitative high-resolution transmission electron microscopy (HRTEM) methods and atomistic molecular dynamics (MD) calculations. Full determination of the elastic strain distribution can be exploited for band gap tailoring of the heterostructures by controlling the content of the active elements, and thus influence the emitted radiation.

Surfactant-assisted emulsification dispersive liquid-liquid microextraction using 2-thenoyltrifluoroacetone as a chelating agent coupled with electrothermal atomic absorption spectrometry for the speciation of chromium in water and rice samples.

PubMed

Dokpikul, Nattawut; Chaiyasith, Wipharat Chuachuad; Sananmuang, Ratana; Ampiah-Bonney, Richmond J

2018-04-25

A novel method was developed by SAE-DLLME for chromium speciation in water and rice samples using 2-thenoyltrifluoroacetone (TTA) as a chelating reagent by ETAAS. The speciation of Cr(III) and Cr(VI) was achieved by complexation of Cr(III)-TTA and the total Cr was measured after reduction of Cr(VI) to Cr. The calibration graph was linear in the range of 0.02-2.50 µg L -1 , with a detection limit of 0.0052 µg L -1 . The %RSD was in range of 2.90-3.30% at 0.5, 1.5 and 2.5 µg L -1 of Cr(III), n = 5 and the EF was 54.47. The method was applied to chromium speciation and total chromium determination in real samples and gave recoveries in the range of 96.2-103.5% and 97.1-102.7% for Cr(III) and Cr(VI) in water samples and 93.7-103.5% of total Cr in rice samples. The accuracy of the method was evaluated by analysis of SRM 1573a with good agreement compared to the certified value. Copyright © 2017 Elsevier Ltd. All rights reserved.

Site classification for National Strong Motion Observation Network System (NSMONS) stations in China using an empirical H/V spectral ratio method

NASA Astrophysics Data System (ADS)

Ji, Kun; Ren, Yefei; Wen, Ruizhi

2017-10-01

Reliable site classification of the stations of the China National Strong Motion Observation Network System (NSMONS) has not yet been assigned because of lacking borehole data. This study used an empirical horizontal-to-vertical (H/V) spectral ratio (hereafter, HVSR) site classification method to overcome this problem. First, according to their borehole data, stations selected from KiK-net in Japan were individually assigned a site class (CL-I, CL-II, or CL-III), which is defined in the Chinese seismic code. Then, the mean HVSR curve for each site class was computed using strong motion recordings captured during the period 1996-2012. These curves were compared with those proposed by Zhao et al. (2006a) for four types of site classes (SC-I, SC-II, SC-III, and SC-IV) defined in the Japanese seismic code (JRA, 1980). It was found that an approximate range of the predominant period Tg could be identified by the predominant peak of the HVSR curve for the CL-I and SC-I sites, CL-II and SC-II sites, and CL-III and SC-III + SC-IV sites. Second, an empirical site classification method was proposed based on comprehensive consideration of peak period, amplitude, and shape of the HVSR curve. The selected stations from KiK-net were classified using the proposed method. The results showed that the success rates of the proposed method in identifying CL-I, CL-II, and CL-III sites were 63%, 64%, and 58% respectively. Finally, the HVSRs of 178 NSMONS stations were computed based on recordings from 2007 to 2015 and the sites classified using the proposed method. The mean HVSR curves were re-calculated for three site classes and compared with those from KiK-net data. It was found that both the peak period and the amplitude were similar for the mean HVSR curves derived from NSMONS classification results and KiK-net borehole data, implying the effectiveness of the proposed method in identifying different site classes. The classification results have good agreement with site classes based on borehole data of 81 stations in China, which indicates that our site classification results are acceptable and that the proposed method is practicable.

Synthesis and characterization of a new Inonotus obliquus polysaccharide-iron(III) complex.

PubMed

Wang, Jia; Chen, Haixia; Wang, Yanwei; Xing, Lisha

2015-04-01

A new Inonotus obliquus polysaccharide-iron(III) complex (IOPS-iron) was synthesized and characterized. The preparation conditions of IOPS-iron(III) were optimized and the physicochemical properties were characterized by physicochemical methods, scanning electron microscopy (SEM), electron paramagnetic resonance (EPR) spectroscopy, fourier transform infrared (FTIR) spectroscopy, circular dichroism (CD) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy, respectively. The highest iron content of IOPS-iron(III) complex (19.40%) was obtained at the conditions: the ratio of IOPS and FeCl3 • 6H2O was 3:5 (w/w), the pH value of alkali solution was 10, the reaction temperature was 30 °C and the reaction time was 6h. The iron(III) was shown to be bound through the binding sites of the polysaccharide IOPS and it could form spatially separated iron centers on the polysaccharide backbone. IOPS-iron(III) complex was found to have good digestive availability and antioxidant activities in the in vitro assays, which suggested the IOPS-iron(III) complex might be used as a new iron supplement candidate. Copyright © 2015 Elsevier B.V. All rights reserved.

Modeling the Kinetics of Contaminants Oxidation and the Generation of Manganese(III) in the Permanganate/Bisulfite Process.

PubMed

Sun, Bo; Dong, Hongyu; He, Di; Rao, Dandan; Guan, Xiaohong

2016-02-02

Permanganate can be activated by bisulfite to generate soluble Mn(III) (noncomplexed with ligands other than H2O and OH(-)) which oxidizes organic contaminants at extraordinarily high rates. However, the generation of Mn(III) in the permanganate/bisulfite (PM/BS) process and the reactivity of Mn(III) toward emerging contaminants have never been quantified. In this work, Mn(III) generated in the PM/BS process was shown to absorb at 230-290 nm for the first time and disproportionated more easily at higher pH, and thus, the utilization rate of Mn(III) for decomposing organic contaminant was low under alkaline conditions. A Mn(III) generation and utilization model was developed to get the second-order reaction rate parameters of benzene oxidation by soluble Mn(III), and then, benzene was chosen as the reference probe to build a competition kinetics method, which was employed to obtain the second-order rate constants of organic contaminants oxidation by soluble Mn(III). The results revealed that the second-order rate constants of aniline and bisphenol A oxidation by soluble Mn(III) were in the range of 10(5)-10(6) M(-1) s(-1). With the presence of soluble Mn(III) at micromolar concentration, contaminants could be oxidized with the observed rates several orders of magnitude higher than those by common oxidation processes, implying the great potential application of the PM/BS process in water and wastewater treatment.

Routine Treatment of Cervical Cytological Cell Changes: Diagnostic Standard, Prevention and Routine Treatment of Cervical Cytological Cell Changes - An Assessment of Primary and Secondary Prevention and Routine Treatment Data in the Context of an Anonymous Data Collection from Practicing Gynaecologists; an Academic, Non-Interventional Study.

PubMed

Huber, J; Pötsch, B; Gantschacher, M; Templ, M

2016-10-01

Introduction: Diagnosis and treatment of vaginal and cervical cytological cell changes are described in European and national guidelines. The aim of this data collection was to evaluate the remission rates of PAP III and PAP III D cytological findings in patients over a period of 3-4 months. Method: The current state of affairs in managing suspicious and cytological findings (PAP III, and III D) in gynecological practice was assessed in the context of a data collection survey. An evaluation over a period of 24 months was conducted on preventative measures, the occurrence and changes to normal/suspect/pathological findings and therapy management (for suspicious or pathological findings). Results: 307 female patients were included in the analysis. At the time of the survey 186 patients (60.6 %) had PAP III and 119 (38.8 %) had PAP III D findings. The spontaneous remission rate of untreated PAP III patients was 6 % and that of untreated PAP III D patients was 11 %. The remission rates of patients treated with a vaginal gel were 77 % for PAP III and 71 % for PAP III D. Conclusion: A new treatment option was used in gynecological practice on patients with PAP III and PAP III D findings between confirmation and the next follow-up with excellent success.

Structures and phase transitions in a new ferroelectric -- pyridinium chlorochromate -- studied by X-ray diffraction, DSC and dielectric methods.

PubMed

Małuszyńska, Hanna; Czarnecki, Piotr; Czarnecka, Anna; Pająk, Zdzisław

2012-04-01

Pyridinium chlorochromate, [C(5)H(5)NH](+)[ClCrO(3)](-) (hereafter referred to as PyClCrO(3)), was studied by X-ray diffraction, differential scanning calorimetry (DSC) and dielectric methods. Studies reveal three reversible phase transitions at 346, 316 and 170 K with the following phase sequence: R ̅3m (I) → R3m (II) → Cm (III) → Cc (IV), c' = 2c. PyClCrO(3) is the first pyridinium salt in which all four phases have been successfully characterized by a single-crystal X-ray diffraction method. Structural results together with dielectric and calorimetric studies allow the classification of the two intermediate phases (II) and (III) as ferroelectric with the Curie point at 346 K, and the lowest phase (IV) as most probably ferroelectric. The ferroelectric hysteresis loop was observed only in phase (III). The high ionic conductivity hindered its observation in phase (II).

Quantum theory of the structure and bonding in proteins. Part 11. A simplified method and its application to the α-amino-isobutyric acid residue

NASA Astrophysics Data System (ADS)

Peters, David; Peters, Jane

Information about the preferred conformation of the α-amino-isobutyric acid residue (α-AIB) is obtained without explicit computation of its wave function. The conformation of lowest energy of this residue is close to the usual helical conformation and so the residue may occur at the 2 position of a type I or I' bend or in either position of a type III or III' bend. The available experimental information refers to a β bend formed from α-AIB-PRO and then the theory and experiment agree that the only possibility is a type III bend. It is predicted that a β sheet structure may be formed at rather higher energy and in the planar and not the pleated form. There is no apparent reason why this residue should not form an α helix. The simplified method used here is closely related to the partitioned potential energy methods which are widely used in this subject.

Iron species determination by task-specific ionic liquid-based in situ solvent formation dispersive liquid-liquid microextraction combined with flame atomic absorption spectrometry.

PubMed

Sadeghi, Susan; Ashoori, Vahid

2017-10-01

The task-specific ionic liquid (TSIL) of 1-ethyl-3-methylimidazolium bromide functionalized with 8-hydroxyquinoline was used as a chelating agent and extracting solvent for dispersive liquid-liquid microextraction and subsequent determination of Fe(III) by flame atomic absorption spectrometry. The in situ solvent formation of TSIL using KPF 6 provided the desired water-immiscible ionic liquid. The total Fe concentration could be determined after pre-oxidation of Fe(II) to Fe(III). Various factors affecting the proposed extraction procedure were optimized. The proposed analytical conditions were: sample pH 5, TSIL amount 0.3% (w/v), KPF 6 amount 0.15% (w/v), anti-sticking 0.1% (w/v) and salt concentration 5% (w/v). Under optimal conditions, the linear dynamic ranges for Fe(III) and total Fe were 20-80 and 20-110 ng mL -1 , respectively, with a detection limit of 6.9 ng mL -1 for Fe(III) and relative standard deviation of 2.2%. The proposed method was successfully applied to the determination of trace Fe(III) in water (underground, tap, refined water and artificial sea water) and beverage (apple, tomato, and tea) samples. The developed method offers advantages such as simplicity, ease of operation, and extraction of Fe(III) from aqueous solutions without the use of organic solvent. It was successfully applied for iron speciation in different real samples. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

New luminescent bioprobes Eu(lll)-phloroglucinol derivatives and their spectrofluorimetric, electrochemical interactions with nucleotides and DNA.

PubMed

Azab, Hassan Ahmed; Anwar, Zeinab M; Abdel-Salam, Enas T; el-Sayed-Sebak, Mahmoud

2012-01-01

Two new ligands derived from phloroglucinol 2-{[(4-methoxy benzoyl)oxy]} methyl benzoic acid[L1] and 2-{[(4-methyl benzoyl)oxy] methyl} benzoic acid[L2] were synthesized. The solid complex Eu(III)-L2 has been synthesised and characterized by elemental analysis, UV and IR spectra. The reaction of Eu(III) with the two synthesized ligands has been investigated in I = 0.1 mol dm(-3) p-toluene sulfonate by cyclic voltammetry and square wave voltammetry. The reaction of Eu (III)-L1 and Eu (III)-L2 binary complexes with nucleotide 5'-AMP, 5'-ADP, 5'-ATP, 5'- GMP, 5'-IMP, and 5'-CMP has been investigated using UV, fluorescence and electrochemical methods. The experimental conditions were selected such that self-association of the nucleotides and their complexes was negligibly small, that is, the monomeric complexes were studied. The interaction of the Eu(III)-L1 or L2 solid complexes with calf-thymus DNA has been investigated by fluorescence and electrochemical methods including cyclic voltammetery(CV), differential pulse polarography (DPP) and square wave voltammetry (SWV) on a glassy carbon electrode. The fluorescence intensity of Eu(III)-L2 complex was enhanced with the addition of DNA. Under optimal conditions in phosphate buffer pH 7.0 at 25 °C the linear range is 3-20 μM for calf thymus DNA (CT-DNA) and the corresponding determination limit is 1.8 μM.

A carbon dot-based "off-on" fluorescent probe for highly selective and sensitive detection of phytic acid.

PubMed

Gao, Zhao; Wang, Libing; Su, Rongxin; Huang, Renliang; Qi, Wei; He, Zhimin

2015-08-15

We herein report a facile, one-step pyrolysis synthesis of photoluminescent carbon dots (CDs) using citric acid as the carbon source and lysine as the surface passivation reagent. The as-prepared CDs show narrow size distribution, excellent blue fluorescence and good photo-stability and water dispersivity. The fluorescence of the CDs was found to be effectively quenched by ferric (Fe(III)) ions with high selectivity via a photo-induced electron transfer (PET) process. Upon addition of phytic acid (PA) to the CDs/Fe(III) complex dispersion, the fluorescence of the CDs was significantly recovered, arising from the release of Fe(III) ions from the CDs/Fe(III) complex because PA has a higher affinity for Fe(III) ions compared to CDs. Furthermore, we developed an "off-on" fluorescence assay method for the detection of phytic acid using CDs/Fe(III) as a fluorescent probe. This probe enables the selective detection of PA with a linear range of 0.68-18.69 μM and a limit of detection (signal-to-noise ratio is 3) of 0.36 μM. The assay method demonstrates high selectivity, repeatability, stability and recovery ratio in the detection of the standard and real PA samples. We believe that the facile operation, low-cost, high sensitivity and selectivity render this CD-based "off-on" fluorescent probe an ideal sensing platform for the detection of PA. Copyright © 2015 Elsevier B.V. All rights reserved.

Combining Ferric Salt and Cactus Mucilage for Arsenic Removal from Water.

PubMed

Fox, Dawn I; Stebbins, Daniela M; Alcantar, Norma A

2016-03-01

New methods to remediate arsenic-contaminated water continue to be studied, particularly to fill the need for accessible methods that can significantly impact developing communities. A combination of cactus mucilage and ferric (Fe(III)) salt was investigated as a flocculation-coagulation system to remove arsenic (As) from water. As(V) solutions, ferric nitrate, and mucilage suspensions were mixed and left to stand for various periods of time. Visual and SEM observations confirmed the flocculation action of the mucilage as visible flocs formed and settled to the bottom of the tubes within 3 min. The colloidal suspensions without mucilage were stable for up to 1 week. Sample aliquots were tested for dissolved and total arsenic by ICP-MS and HGAFS. Mucilage treatment improved As removal (over Fe(III)-only treatment); the system removed 75-96% As in 30 min. At neutral pH, removal was dependent on Fe(III) and mucilage concentration and the age of the Fe(III) solution. The process is fast, achieving maximum removal in 30 min, with the majority of As removed in 10-15 min. Standard jar tests with 1000 μg/L As(III) showed that arsenic removal and settling rates were pH-dependent; As removal was between 52% (high pH) and 66% (low pH).

Fusion Protein Vaccines Targeting Two Tumor Antigens Generate Synergistic Anti-Tumor Effects

PubMed Central

Cheng, Wen-Fang; Chang, Ming-Cheng; Sun, Wei-Zen; Jen, Yu-Wei; Liao, Chao-Wei; Chen, Yun-Yuan; Chen, Chi-An

2013-01-01

Introduction Human papillomavirus (HPV) has been consistently implicated in causing several kinds of malignancies, and two HPV oncogenes, E6 and E7, represent two potential target antigens for cancer vaccines. We developed two fusion protein vaccines, PE(ΔIII)/E6 and PE(ΔIII)/E7 by targeting these two tumor antigens to test whether a combination of two fusion proteins can generate more potent anti-tumor effects than a single fusion protein. Materials and Methods In vivo antitumor effects including preventive, therapeutic, and antibody depletion experiments were performed. In vitro assays including intracellular cytokine staining and ELISA for Ab responses were also performed. Results PE(ΔIII)/E6+PE(ΔIII)/E7 generated both stronger E6 and E7-specific immunity. Only 60% of the tumor protective effect was observed in the PE(ΔIII)/E6 group compared to 100% in the PE(ΔIII)/E7 and PE(ΔIII)/E6+PE(ΔIII)/E7 groups. Mice vaccinated with the PE(ΔIII)/E6+PE(ΔIII)/E7 fusion proteins had a smaller subcutaneous tumor size than those vaccinated with PE(ΔIII)/E6 or PE(ΔIII)/E7 fusion proteins alone. Conclusion Fusion protein vaccines targeting both E6 and E7 tumor antigens generated more potent immunotherapeutic effects than E6 or E7 tumor antigens alone. This novel strategy of targeting two tumor antigens together can promote the development of cancer vaccines and immunotherapy in HPV-related malignancies. PMID:24058440

Effect of arsenite-oxidizing bacterium B. laterosporus on arsenite toxicity and arsenic translocation in rice seedlings.

PubMed

Yang, Gui-Di; Xie, Wan-Ying; Zhu, Xi; Huang, Yi; Yang, Xiao-Jun; Qiu, Zong-Qing; Lv, Zhen-Mao; Wang, Wen-Na; Lin, Wen-Xiong

2015-10-01

Arsenite [As (III)] oxidation can be accelerated by bacterial catalysis, but the effects of the accelerated oxidation on arsenic toxicity and translocation in rice plants are poorly understood. Herein we investigated how an arsenite-oxidizing bacterium, namely Brevibacillus laterosporus, influences As (III) toxicity and translocation in rice plants. Rice seedlings of four cultivars, namely Guangyou Ming 118 (GM), Teyou Hang II (TH), Shanyou 63 (SY) and Minghui 63 (MH), inoculated with or without the bacterium were grown hydroponically with As (III) to investigate its effects on arsenic toxicity and translocation in the plants. Percentages of As (III) oxidation in the solutions with the bacterium (100%) were all significantly higher than those without (30-72%). The addition of the bacterium significantly decreased As (III) concentrations in SY root, GM root and shoot, while increased the As (III) concentrations in the shoot of SY, MH and TH and in the root of MH. Furthermore, the As (III) concentrations in the root and shoot of SY were both the lowest among the treatments with the bacterium. On the other hand, its addition significantly alleviated the As (III) toxicity on four rice cultivars. Among the treatments amended with B. laterosporus, the bacterium showed the best remediation on SY seedlings, with respect to the subdued As (III) toxicity and decreased As (III) concentration in its roots. These results indicated that As (III) oxidation accelerated by B. laterosporus could be an effective method to alleviate As (III) toxicity on rice seedlings. Copyright © 2015 Elsevier Inc. All rights reserved.

Development and validation of a simple and robust method for arsenic speciation in human urine using HPLC/ICP-MS.

PubMed

Sen, Indranil; Zou, Wei; Alvaran, Josephine; Nguyen, Linda; Gajek, Ryszard; She, Jianwen

2015-01-01

In order to better distinguish the different toxic inorganic and organic forms of arsenic (As) exposure in individuals, we have developed and validated a simple and robust analytical method for determining the following six As species in human urine: arsenous (III) acid (As-III), As (V) acid, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine (AsB), and arsenocholine. In this method, human urine is diluted using a pH 5.8 buffer, separation is performed using an anion exchange column with isocratic HPLC, and detection is achieved using inductively coupled plasma-MS. The method uses a single mobile phase consisting of low concentrations of both phosphate buffer (5 mM) and ammonium nitrate salt (5 mM) at pH 9.0; this minimizes the column equilibration time and overcomes challenges with separation between AsB and As-III. In addition, As-III oxidation is prevented by degassing the sample preparation buffer at pH 5.8, degassing the mobile phase online at pH 9.0, and by the use of low temperature (-70 °C) and flip-cap airtight tubes for long term storage of samples. The method was validated using externally provided reference samples. Results were in agreement with target values at varying concentrations and successfully passed external performance test criteria. Internal QC samples were prepared and repeatedly analyzed to assess the method's long-term precision, and further analyses were completed on anonymous donor urine to assess the quality of the method's baseline separation. Results from analyses of external reference samples agreed with target values at varying concentrations, and results from precision studies yielded absolute CV values of 3-14% and recovery from 82 to 115% for the six As species. Analysis of anonymous donor urine confirmed the well-resolved baseline separation capabilities of the method for real participant samples.

Comparison of Intraabdominal and Trocar Site Local Anaesthetic Infiltration on Postoperative Analgesia After Laparoscopic Cholecystectomy.

PubMed

Altuntaş, Gülsüm; Akkaya, Ömer Taylan; Özkan, Derya; Sayın, Mehmet Murat; Balas, Şener; Özlü, Elif

2016-12-01

This study aimed to compare the efficacy of local anaesthetic infiltration to trocar wounds and intraperitoneally on postoperative pain as a part of a multimodal analgesia method after laparoscopic cholecystectomies. The study was performed on 90 ASA I-III patients aged between 20 and 70 years who underwent elective laparoscopic cholecystectomy. All patients had the same general anaesthesia drug regimen. Patients were randomized into three groups by a closed envelope method: group I (n=30), trocar site local anaesthetic infiltration (20 mL of 0.5% bupivacaine); group II (n=30), intraperitoneal local anaesthetic instillation (20 mL of 0.5%) and group III (n=30), saline infiltration both trocar sites and intraperitoneally. Postoperative i.v. patient controlled analgesia was initiated for 24 h. In total, 4 mg of i.v. ondansetron was administered to all patients. Visual analogue scale (VAS), nausea and vomiting and shoulder pain were evaluated at 1., 2., 4., 8., 12., 24. hours. An i.v. nonsteroidal anti-inflammatory drug (NSAID) (50 mg of dexketoprofen) as a rescue analgesic was given if the VAS was ≥5. There were no statistical significant differences between the clinical and demographic properties among the three groups (p≥0.005). During all periods, VAS in group I was significantly lower than that in groups II and III (p<0.001). Among the groups, although there was no significant difference in nausea and vomiting (p=0.058), there was a significant difference in shoulder pain. Group III (p<0.05) had more frequent shoulder pain than groups I and II. The total morphine consumption was higher in groups II and III (p<0.001 vs p<0.001) than in group I. The requirement for a rescue analgesic was significantly higher in group III (p<0.05). Trocar site local anaesthetic infiltration is more effective for postoperative analgesia, easier to apply and safer than other analgesia methods. Morphine consumption is lesser and side effects are fewer; therefore, this method can be used as a part of common practice.

III-V aresenide-nitride semiconductor materials and devices

NASA Technical Reports Server (NTRS)

Major, Jo S. (Inventor); Welch, David F. (Inventor); Scifres, Donald R. (Inventor)

1997-01-01

III-V arsenide-nitride semiconductor crystals, methods for producing such crystals and devices employing such crystals. Group III elements are combined with group V elements, including at least nitrogen and arsenic, in concentrations chosen to lattice match commercially available crystalline substrates. Epitaxial growth of these III-V crystals results in direct bandgap materials, which can be used in applications such as light emitting diodes and lasers. Varying the concentrations of the elements in the III-V crystals varies the bandgaps, such that materials emitting light spanning the visible spectra, as well as mid-IR and near-UV emitters, can be created. Conversely, such material can be used to create devices that acquire light and convert the light to electricity, for applications such as full color photodetectors and solar energy collectors. The growth of the III-V crystals can be accomplished by growing thin layers of elements or compounds in sequences that result in the overall lattice match and bandgap desired.

Electrochemical Sensing toward Trace As(III) Based on Mesoporous MnFe₂O₄/Au Hybrid Nanospheres Modified Glass Carbon Electrode.

PubMed

Zhou, Shaofeng; Han, Xiaojuan; Fan, Honglei; Liu, Yaqing

2016-06-22

Au nanoparticles decorated mesoporous MnFe₂O₄ nanocrystal clusters (MnFe₂O₄/Au hybrid nanospheres) were used for the electrochemical sensing of As(III) by square wave anodic stripping voltammetry (SWASV). Modified on a cheap glass carbon electrode, these MnFe₂O₄/Au hybrid nanospheres show favorable sensitivity (0.315 μA/ppb) and limit of detection (LOD) (3.37 ppb) toward As(III) under the optimized conditions in 0.1 M NaAc-HAc (pH 5.0) by depositing for 150 s at the deposition potential of -0.9 V. No obvious interference from Cd(II) and Hg(II) was recognized during the detection of As(III). Additionally, the developed electrode displayed good reproducibility, stability, and repeatability, and offered potential practical applicability for electrochemical detection of As(III) in real water samples. The present work provides a potential method for the design of new and cheap sensors in the application of electrochemical determination toward trace As(III) and other toxic metal ions.

Poly(1-vinylimidazole) functionalized magnetic ion imprinted polymer for fast and selective extraction of trace gold in geological, environmental and biological samples followed by graphite furnace atomic absorption spectrometry detection

NASA Astrophysics Data System (ADS)

Zhao, Bingshan; He, Man; Chen, Beibei; Xu, Hongrun; Hu, Bin

2018-05-01

In this study, poly(1-vinylimidazole) functionalized gold ion imprinted polymer coated magnetic nanoparticles (MNPs@PVIM-Au-IIP) were prepared and characterized. The adsorption behaviors of the prepared MNPs@PVIM-Au-IIP toward gold ions (Au(III)) were studied, it was found that MNPs@PVIM-Au-IIP has good selectivity, high adsorption capacity (185.4 mg g-1) and fast adsorption kinetic for Au(III). Based on it, a new method of ion imprinted magnetic solid phase extraction (II-MSPE) coupled with graphite furnace atomic absorption spectrometry (GFAAS) detection was proposed for the analysis of trace Au(III) in real samples with complicated matrix. Factors affecting MSPE including sample pH, desorption reagent, elution concentration and volume, elution time, sample volume and adsorption time were optimized. With high enrichment factor of 100-fold, the detection limit of the proposed method is 7.9 ng L-1 for Au(III) with the relative standard deviation of 7.4% (c = 50 ng L-1, n = 7). In order to validate the accuracy of the proposed method, the Certified Reference Material of GBW07293 geological sample (platinpalladium ore) was analyzed, and the determined value was in good agreement with the certified value. The proposed II-MSPE-GFAAS method is simple, fast, selective, sensitive and has been successfully applied in the determination of trace Au in ore, sediment, environmental water and human urine samples with satisfactory results.

Comparison of Electrotherapy, Rubber Band Ligation and Hemorrhoidectomy in the Treatment of Hemorrhoids: A Clinical and Manometric Study

PubMed Central

Izadpanah, A; Hosseini, SV; Mahjoob, M

2010-01-01

BACKGROUND Treatment of hemorrhoid disease is one of the most challenging fields in general surgery in which different methods are used to treat this condition. In this study, we compared the manometric and clinical results of three treatment methods for hemorrhoids. METHODS A total of 150 patients with symptomatic grades II or III internal hemorrhoids were randomly assigned to three groups. Group A underwent Ferguson hemorrhoidectomy, group B were treated with rubber band ligation (RBL) and group C were treated with direct current electrotherapy. RESULTS Preoperatively, grade III hemorrhoids had significantly higher mean resting pressure and mean squeezing pressure in comparison to grade II hemorrhoids. After hemorrhoidectomy, patients in group A had a significant decrease in the maximum resting pressure (90.8 to 77.7 mmHg) and maximum squeezing pressure (130.6 to 114.8 mmHg) with a significant raise in the volume of the first sensation. However there was no significant change in manometric indexes after RBL and electrotherapy. Group A patients had more postoperative pain and itching compared to groups B and C. CONCLUSION We conclude that electrotherapy is a safe, effective and simple method of treating grades II and III uncomplicated internal hemorrhoids. This procedure is associated with little postoperative pain and complications, and has the least changes in anorectal manometric characteristics. Therefore electrotherapy may be recommended as a treatment of choice for grades II and III uncomplicated internal hemorrhoids. PMID:25197506

Determination of Sulfonamide Residues in Food by Capillary Zone Electrophoresis with On-Line Chemiluminescence Detection Based on an Ag(III) Complex.

PubMed

Dai, Tingting; Duan, Jie; Li, Xinghua; Xu, Xiangdong; Shi, Hongmei; Kang, Weijun

2017-06-16

The presence of sulfonamide (SA) residues in foods is largely due to the raising of animals with sulfonamide antibiotics added or polluted feedstuff. In this paper, a sensitive method was developed for the determination of the residues of three sulfonamides in animal-derived food; the SAs include sulfadimidine (SDD), sulfadiazine (SDZ), and sulfathiazole (STZ). The method is based on capillary zone electrophoresis (CE) with online chemiluminescence (CL) detection, using an Ag(III) complex as an oxidant. These SAs have an inhibiting effect on the Ag(III)-luminol CL reaction. The electrophoretic buffer is 12.0 mM sodium borate. Under a set of optimized conditions, the linear ranges for the detections were found to be 10.0-200 µg·mL -1 for SDD and SDZ, and 2.0-50.0 µg·mL -1 for STZ. The detection limits were 2.75, 3.14, and 0.65 µg·mL -1 for SDD, SDZ, and STZ, respectively. Relative standard deviations (RSD) for the peak heights were between 2.1% and 2.8% (n = 7). The proposed method was used in the analysis of the SAs in samples from pork meat, chicken meat, and milk, showing satisfactory detection results. A reaction mechanism was also proposed for the Ag(III)-luminol-SA CL reactions. The method has potential applications for the monitoring of residue levels of the three SAs in food, providing food safety data.

On-line preconcentration and speciation of arsenic by flow injection hydride generation atomic absorption spectrophotometry.

PubMed

Narcise, Cristine Ingrid S; Coo, Lilibeth Dlc; Del Mundo, Florian R

2005-12-15

A flow injection-column preconcentration-hydride generation atomic absorption spectrophotometric (FI-column-HGAAS) method was developed for determining mug/l levels of As(III) and As(V) in water samples, with simultaneous preconcentration and speciation. The speciation scheme involved determining As(V) at neutral pH and As(III+V) at pH 12, with As(III) obtained by difference. The enrichment factor (EF) increased with increase in sample loading volume from 2.5 to 10ml, and for preconcentration using the chloride-form anion exchange column, EFs ranged from 5 to 48 for As(V) and 4 to 24 for As(III+V), with corresponding detection limits of 0.03-0.3 and 0.07-0.3mug/l. Linear concentration range (LCR) also varied with sample loading volume, and for a 5-ml sample was 0.3-5 and 0.2-8mug/l for As(V) and As(III+V), respectively. Sample throughput, which decreased with increase in sample volume, was 8-17 samples/h. For the hydroxide-form column, the EFS for 2.5-10ml samples were 3-23 for As(V) and 2-15 for As(III+V), with corresponding detection limits of 0.07-0.4 and 0.1-0.5mug/l. The LCR for a 5-ml sample was 0.3-10mug/l for As(V) and 0.2-20mug/l for As(III+V). Sample throughput was 10-20 samples/h. The developed method has been effectively applied to tap water and mineral water samples, with recoveries ranging from 90 to 102% for 5-ml samples passed through the two columns.

Cataract prevalence varies substantially with assessment systems: comparison of clinical and photographic grading in a population-based study.

PubMed

Tan, Anna C S; Wang, Jie Jin; Lamoureux, Ecosse L; Wong, Wanling; Mitchell, Paul; Li, Jialiang; Tan, Ava Grace; Wong, Tien Y

2011-08-01

Cataract is the major cause of blindness worldwide yet there is no consensus on its assessment and definition. This study compares age-related cataract prevalence derived from two commonly used methods: clinical assessment using the Lens Opacity Classification System (LOCS III) and photographic grading using the Wisconsin Cataract Grading System (Wisconsin System). The Singapore Malay Eye Study is a population-based study of 3,280 Singapore Malays aged 40-80 years. Presence of nuclear, cortical and posterior sub-capsular cataract was assessed clinically during slit-lamp examination using LOCS III, and via slit-lamp and retro-illumination photographic grading using the Wisconsin System. Analyses were conducted to determine agreement in cataract prevalence estimates between the two grading Systems and approaches. Poor agreement was found between severity levels of the two grading scales for all three cataract types. Using currently accepted cut-offs to define nuclear (≥ 4 on both LOCS III and Wisconsin System), cortical (≥ 2 in LOCS III, ≥ 25% in Wisconsin) and PSC (≥ 2 in LOCS III, ≥ 5 % in Wisconsin) cataract, the LOCS III overestimated the prevalence of significant cataract as compared to the Wisconsin System, with nuclear cataract prevalence, 27.5% (LOCS III) versus 17.0% (Wisconsin System), cortical cataract prevalence, 27.9% versus 7.0% and posterior sub-capsular cataract prevalence, 7.8% versus 5.1%. The prevalence of cataract in a population varies substantially by measurement methods, with systematically different estimates found using the two most frequent cataract grading systems. This study re-emphasizes the need for global standards to assess and define cataract for epidemiologic and clinical studies.

Single peak parameters technique for simultaneous measurements: Spectrophotometric sequential injection determination of Fe(II) and Fe(III).

PubMed

Kozak, J; Paluch, J; Węgrzecka, A; Kozak, M; Wieczorek, M; Kochana, J; Kościelniak, P

2016-02-01

Spectrophotometric sequential injection system (SI) is proposed to automate the method of simultaneous determination of Fe(II) and Fe(III) on the basis of parameters of a single peak. In the developed SI system, sample and mixture of reagents (1,10-phenanthroline and sulfosalicylic acid) are introduced into a vessel, where in an acid environment (pH≅3) appropriate compounds of Fe(II) and Fe(III) with 1,10-phenanthroline and sulfosalicylic acid are formed, respectively. Then, in turn, air, sample, EDTA and sample again, are introduced into a holding coil. After the flow reversal, a segment of air is removed from the system by an additional valve and as EDTA replaces sulfosalicylic acid forming a more stable colorless compound with Fe(III), a complex signal is registered. Measurements are performed at wavelength 530 nm. The absorbance measured at minimum of the negative peak and the area or the absorbance measured at maximum of the signal can be used as measures corresponding to Fe(II) and Fe(III) concentrations, respectively. The time of the peak registration is about 2 min. Two-component calibration has been applied to analysis. Fe(II) and Fe(III) can be determined within the concentration ranges of 0.04-4.00 and 0.1-5.00 mg L(-1), with precision less than 2.8% and 1.7% (RSD), respectively and accuracy better than 7% (RE). The detection limit is 0.04 and 0.09 mg L(-1) for Fe(II) and Fe(III), respectively. The method was applied to analysis of artesian water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Distribution and Translocation of 141Ce (III) in Horseradish

PubMed Central

Guo, Xiaoshan; Zhou, Qing; Lu, Tianhong; Fang, Min; Huang, Xiaohua

2007-01-01

Background and Aims Rare earth elements (REEs) are used in agriculture and a large amount of them contaminate the environment and enter foods. The distribution and translocation of 141Ce (III) in horseradish was investigated in order to help understand the biochemical behaviour and toxic mechanism of REEs in plants. Method The distribution and translocation of 141Ce (III) in horseradish were investigated using autoradiography, liquid scintillation counting (LSC) and electron microscopic autoradiography (EMARG) techniques. The contents of 141Ce (III) and nutrient elements were analysed using an inductively coupled plasma-atomic emission spectrometer (ICP-AES). Results The results from autoradiography and LSC indicated that 141Ce (III) could be absorbed by horseradish and transferred from the leaf to the leaf-stalk and then to the root. The content of 141Ce (III) in different parts of horseradish was as follows: root > leaf-stalk > leaf. The uptake rates of 141Ce (III) in horseradish changed with the different organs and time. The content of 141Ce (III) in developing leaves was greater than that in mature leaves. The results from EMARG indicated that 141Ce (III) could penetrate through the cell membrane and enter the mesophyll cells, being present in both extra- and intra-cellular deposits. The contents of macronutrients in horseradish were decreased by 141Ce (III) treatment. Conclusions 141Ce (III) can be absorbed and transferred between organs of horseradish with time, and the distribution was found to be different at different growth stages. 141Ce (III) can enter the mesophyll cells via apoplast and symplast channels or via plasmodesmata. 141Ce (III) can disturb the metabolism of macronutrients in horseradish. PMID:17921527

Occurrence and Speciation of Polymeric Chromium(III), Monomeric Chromium(III) and Chromium(VI) in Environmental Samples

PubMed Central

HU, LIGANG; CAI, YONG; JIANG, GUIBIN

2016-01-01

Laboratory experiments suggest that polymeric Cr(III) could exist in aqueous solution for a relative long period of time. However, the occurrence of polymeric Cr(III) has not been reported in environmental media due partially to the lack of method for speciating polymeric Cr. We observed an unknown Cr species during the course of study on speciation of Cr in the leachates of chromated-copper-arsenate (CCA)-treated wood. Efforts were made to identify structure of the unknown Cr species. Considering the forms of Cr existed in the CCA-treated woods, we mainly focused our efforts to determine if the unknown species were polymeric Cr(III), complex of Cr/As or complex of Cr with dissolved organic matter (DOM). In order to evaluate whether polymeric Cr(III) largely exist in wood leachates, high performance liquid chromatography coupled with inductively coupled mass spectrometry (HPLC-ICPMS was used) for simultaneous speciation of monomeric Cr(III), polymeric Cr(III), and Cr(VI). In addition to wood leachates where polymeric Cr (III) ranged from 39.1 to 67.4 %, occurrence of the unknown Cr species in other environmental matrices, including surface waters, tap and waste waters, was also investigated. It was found that polymeric Cr(III) could exist in environmental samples containing μg/L level of Cr, at a level up to 60% of total Cr, suggesting that polymeric Cr(III) could significantly exist in natural environments. Failure in quantifying polymeric Cr(III) would lead to the underestimation of total Cr and bias in Cr speciation. The environmental implication of the presence of polymeric Cr(III) species in the environment deserves further study. PMID:27156211

Millon Clinical Multiaxial Inventory-III Subtypes of Opioid Dependence: Validity and Matching to Behavioral Therapies

ERIC Educational Resources Information Center

Ball, Samuel A.; Nich, Charla; Rounsaville, Bruce J.; Eagan, Dorothy; Carroll, Kathleen M.

2004-01-01

The concurrent and predictive validity of 2 different methods of Millon Clinical Multiaxial Inventory-III subtyping (protocol sorting, cluster analysis) was evaluated in 125 recently detoxified opioid-dependent outpatients in a 12-week randomized clinical trial. Participants received naltrexone and relapse prevention group counseling and were…

Concentrated Language Encounter Instruction Model III in Reading and Creative Writing Abilities

ERIC Educational Resources Information Center

Promnont, Piyapong; Rattanavich, Saowalak

2015-01-01

The research is aimed to study the development of eleventh grade students' reading, creative writing abilities, satisfaction taught through the concentrated language encounter instruction method, CLE model III. One experimental group time series design was used, and the data was analyzed by MANOVA with repeated measures, t-test for one-group…

Method to grow group III-nitrides on copper using passivation layers

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

Li, Qiming; Wang, George T; Figiel, Jeffrey T

Group III-nitride epilayers can be grown directly on copper substrates using intermediate passivation layers. For example, single crystalline c-plane GaN can be grown on Cu (110) substrates with MOCVD. The growth relies on a low temperature AlN passivation layer to isolate any alloying reaction between Ga and Cu.

Methods of using thermal tolerant avicelase from Acidothermus cellulolyticus

DOEpatents

Adney, William S [Golden, CO; Vinzant, Todd B [Golden, CO; Ding, Shih-You [Golden, CO; Himmel, Michael E [Golden, CO

2011-04-26

The invention provides a thermal tolerant (thermostable) cellulase, AviIII, that is a member of the glycoside hydrolase (GH) family. AviIII was isolated and characterized from Acidothermus cellulolyticus, and, like many cellulases, the disclosed polypeptide and/or its derivatives may be useful for the conversion of biomass into biofuels and chemicals.

Technical Reports (Part I). End of Project Report, 1968-1971, Volume III.

ERIC Educational Resources Information Center

Western Nevada Regional Education Center, Lovelock.

The pamphlets included in this volume are technical reports prepared as outgrowths of the Student Information Systems of the Western Nevada Regional Education Center (WN-REC) funded by a Title III (Elementary and Secondary Education Act) grant. These reports describe methods of interpreting the printouts from the Student Information System;…

Personality Disorders and Clinical Syndromes in ADHD Prisoners

ERIC Educational Resources Information Center

Gudjonsson, Gisli H.; Wells, June; Young, Susan

2012-01-01

Objective: The main objective of this article is to investigate the type of personality disorders and clinical syndromes (CSs) that were best related to ADHD symptoms among prisoners. Method: The authors screened for childhood and adult ADHD symptoms and administered the Millon Clinical Multiaxial Inventory-III (MCMI-III) to 196 serving prisoners.…

Laser therapy as the method of choice in treating young women with CIN lesions of the uterine cervix and VIN lesions of the vulva

NASA Astrophysics Data System (ADS)

Knapp, Piotr A.

1996-03-01

The aim of the studies was to attempt to investigate the results of treating young women with CIN I - III of the cervix and epithelial VIN I - III lesions of the vulva by means of the laser technique (vaporization).

A novel one-step real-time multiplex PCR assay to detect Streptococcus agalactiae presence and serotypes Ia, Ib, and III.

PubMed

Furfaro, Lucy L; Chang, Barbara J; Payne, Matthew S

2017-09-01

Streptococcus agalactiae is the leading cause of early-onset neonatal sepsis. Culture-based screening methods lack the sensitivity of molecular assays and do not indicate serotype; a potentially important virulence marker. We aimed to develop a multiplex PCR to detect S. agalactiae while simultaneously identifying serotypes Ia, Ib, and III; commonly associated with infant disease. Primers were designed to target S. agalactiae serotype-specific cps genes and the dltS gene. The assay was validated with 512 vaginal specimens from pregnant women. 112 (21.9%) were dltS positive, with 14.3%, 0.9%, and 6.3% of these identified as cps Ia, Ib, and III, respectively. Our assay is a specific and sensitive method to simultaneously detect S. agalactiae and serotypes Ia, Ib, and III in a single step. It is of high significance for clinical diagnostic applications and also provides epidemiological data on serotype, information that may be important for vaccine development and other targeted non-antibiotic therapies. Copyright © 2017 Elsevier Inc. All rights reserved.

Theoretical Prediction of Am(III)/Eu(III) Selectivity to Aid the Design of Actinide-Lanthanide Separation Agents

DOE PAGES

Bryantsev, Vyacheslav S.; Hay, Benjamin P.

2015-03-20

Selective extraction of minor actinides from lanthanides is a critical step in the reduction of radiotoxicity of spent nuclear fuels. However, the design of suitable ligands for separating chemically similar 4f- and 5f-block trivalent metal ions poses a significant challenge. Furthermore, first-principles calculations should play an important role in the design of new separation agents, but their ability to predict metal ion selectivity has not been systematically evaluated. We examine the ability of several density functional theory methods to predict selectivity of Am(III) and Eu(III) with oxygen, mixed oxygen–nitrogen, and sulfur donor ligands. The results establish a computational method capablemore » of predicting the correct order of selectivities obtained from liquid–liquid extraction and aqueous phase complexation studies. To allow reasonably accurate predictions, it was critical to employ sufficiently flexible basis sets and provide proper account of solvation effects. The approach is utilized to estimate the selectivity of novel amide-functionalized diazine and 1,2,3-triazole ligands.« less

Spectrophotometric determination of dopamine hydrochloride in pharmaceutical, banana, urine and serum samples by potassium ferricyanide-Fe(III).

PubMed

Guo, Li; Zhang, Yan; Li, Quanmin

2009-12-01

In the present work, we developed a simple, sensitive and inexpensive method to determine dopamine hydrochloride using potassium ferricyanide-Fe(III) by spectrophotometry. The results show that Fe(III) is deoxidized to Fe(II) by dopamine hydrochloride at pH 4.0, and then Fe(II) reacts with potassium ferricyanide to form a soluble prussian blue (KFe(III)[Fe(II)(CN)6]). The absorbance of this product was monitored over time using a spectrophotometer at an absorption maximum of 735 nm, and the amount of dopamine hydrochloride could be calculated based on the absorbance. A good linear relationship of the concentration of dopamine hydrochloride versus absorbance was observed, and a linear regression equation of A = 0.022 + 0.16921C (microg mL(-1)) was obtained. Moreover, the apparent molar absorption coefficient for the indirect determination of dopamine hydrochloride was 3.2 x 10(4) L mol(-1) cm(-1). This described method has been used to determine dopamine hydrochloride in pharmaceutical, banana, urine and serum samples with satisfactory results.

Investigation of mechanism and critical parameters for removal of arsenic from water using Zr-TiO2 composite.

PubMed

Anđelković, I; Amaizah, N R R; Marković, S B; Stanković, D; Marković, M; Kuzmanović, D; Roglić, G

2017-09-01

Using the microwave-hydrothermal method for the synthesis of composite, high surface density of hydroxyl groups, as an active adsorption sites for arsenic, was obtained. Adsorption mechanisms of As(III) and As(V) onto zirconium-doped titanium dioxide (Zr-TiO 2 ) were investigated and proposed using macroscopic and microscopic methods. Obtained results are suggesting inner-sphere and outer-sphere adsorption mechanisms for As(III) and As(V), respectively. This allowed us to identify parameters that are critical for the successful removal of arsenic from water, which is essential information for further optimization of the removal process. The composite was further applied for the removal of As(III) and As(V) from water in a dynamic flow through the reactor. Column study proved that the removal of both arsenic species below the value recommended by WHO can be achieved. Elution of As(III) and As(V) from the composite can be done by using small amounts of 0.01 M NaOH solution resulting in preconcentration of arsenic species and possible multiple usage of composite.

The development of decision limits for the GH-2000 detection methodology using additional insulin-like growth factor-I and amino-terminal pro-peptide of type III collagen assays.

PubMed

Holt, Richard I G; Böhning, Walailuck; Guha, Nishan; Bartlett, Christiaan; Cowan, David A; Giraud, Sylvain; Bassett, E Eryl; Sönksen, Peter H; Böhning, Dankmar

2015-09-01

The GH-2000 and GH-2004 projects have developed a method for detecting GH misuse based on measuring insulin-like growth factor-I (IGF-I) and the amino-terminal pro-peptide of type III collagen (P-III-NP). The objectives were to analyze more samples from elite athletes to improve the reliability of the decision limit estimates, to evaluate whether the existing decision limits needed revision, and to validate further non-radioisotopic assays for these markers. The study included 998 male and 931 female elite athletes. Blood samples were collected according to World Anti-Doping Agency (WADA) guidelines at various sporting events including the 2011 International Association of Athletics Federations (IAAF) World Athletics Championships in Daegu, South Korea. IGF-I was measured by the Immunotech A15729 IGF-I IRMA, the Immunodiagnostic Systems iSYS IGF-I assay and a recently developed mass spectrometry (LC-MS/MS) method. P-III-NP was measured by the Cisbio RIA-gnost P-III-P, Orion UniQ™ PIIINP RIA and Siemens ADVIA Centaur P-III-NP assays. The GH-2000 score decision limits were developed using existing statistical techniques. Decision limits were determined using a specificity of 99.99% and an allowance for uncertainty because of the finite sample size. The revised Immunotech IGF-I - Orion P-III-NP assay combination decision limit did not change significantly following the addition of the new samples. The new decision limits are applied to currently available non-radioisotopic assays to measure IGF-I and P-III-NP in elite athletes, which should allow wider flexibility to implement the GH-2000 marker test for GH misuse while providing some resilience against manufacturer withdrawal or change of assays. Copyright © 2015 John Wiley & Sons, Ltd.

Rapid and highly efficient preconcentration of Eu(III) by core-shell structured Fe3O4@humic acid magnetic nanoparticles.

PubMed

Yang, Shitong; Zong, Pengfei; Ren, Xuemei; Wang, Qi; Wang, Xiangke

2012-12-01

In this study, humic acid-coated Fe(3)O(4) magnetic nanoparticles (Fe(3)O(4)@HA MNPs) were synthesized using a chemical coprecipitation method and characterized in detail. The XRD analysis results showed that HA coating did not change the phase of Fe(3)O(4) cores. The TEM image suggested that Fe(3)O(4)@HA MNPs had nearly uniform size without the observation of aggregation. The Fe(3)O(4)@HA MNPs were stable in solution and could be easily separated from aqueous solution using a magnetic separation method. A batch technique was adopted to investigate the removal efficiency of Fe(3)O(4)@HA MNPs toward Eu(III) under various environmental conditions. The kinetic process of Eu(III) sorption on Fe(3)O(4)@HA MNPs reached equilibrium within <30 min. The fast sorption kinetics and high sorption amount were attributed to the plentiful surface sites provided by the surface-coated HA macromolecules. The Fe(3)O(4)@HA MNPs was able to remove ~99% of Eu(III) in aqueous solution at pH 8.5. Except for SO(4)(2-) anions, the coexisting electrolyte ions had no significant competition effects on the removal of Eu(III) by Fe(3)O(4)@HA MNPs. The obvious sorption-desorption hysteresis suggested that the removal of Eu(III) was dominated by inner-sphere surface complexation. The sorption isotherm agreed well with the Langmuir model, having a maximum sorption capacity of 6.95 × 10(-5) mol g(-1). The leaching test showed that the Eu(III)-loaded Fe(3)O(4)@HA colloids were capable to maintain high thermodynamic stability for long aging times. The findings herein suggested that Fe(3)O(4)@HA MNPs could be potentially used as a highly effective material for the enrichment and preconcentration of radionuclide Eu(III) or other trivalent lanthanides/actinides in geological repositories or in nuclear waste management.

Permanganate/bisulfite (PM/BS) conditioning-horizontal electro-dewatering (HED) of activated sludge: Effect of reactive Mn(III) species.

PubMed

Guo, Xinxin; Wang, Yili; Wang, Dongsheng

2017-11-01

A novel activated sludge (AS) conditioning method through permanganate/bisulfate (PM/BS) process was proposed. The method involved a new conditioner of reactive Mn(III) intermediate. Moreover, a Mn(III) conditioning-horizontal electro-dewatering (Mn(III) C-HED) process was established to improve AS dewatering performance. Underlying mechanisms were unraveled by investigating changes in physicochemical characteristics, scanning electron microscope (SEM) morphology, and transformation of water and organic matters. The optimum dewatering conditions for Mn(III) C-HED process with the final water content of 86.94% were determined as the combination of KMnO 4 0.01 mol/L AS and NaHSO 3 0.05 mol/L AS at 20 V for 120 min. Results showed that Mn(III) C-HED process effectively reduced free water and bound water with the corresponding removal ratios of 51.68% and 87.62% at the anode-side as well as 36.55% and 85.08% at the cathode-side, respectively. During the PM/BS process, the produced Mn(III), Mn 2+ , and MnO 2 exerted chemical and physical effects on AS conditioning and dewatering. Mn(III) disintegrated extracellular polymeric substances (EPS) fractions and cells in AS, as well as induced partial bound water release. Additionally, flocculation effect induced by Mn 2+ and MnO 2 skeleton building also benefited AS dewatering. AS cells were further disrupted under the effect of a horizontal electric field. Accordingly, EPS within the AS matrix was solubilized, tightly bound (TB)-EPS or loosely bound (LB)-EPS was converted to their corresponding outer EPS fractions, and AS dewaterability improved. Additionally, changes in pH and temperature at HED stage damaged the AS cells and changed the floc properties, thereby leading to easy separation of liquid and AS particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Zwitterion-functionalized polymer microspheres as a sorbent for solid phase extraction of trace levels of V(V), Cr(III), As(III), Sn(IV), Sb(III) and Hg(II) prior to their determination by ICP-MS.

PubMed

Jia, Xiaoyu; Gong, Dirong; Zhao, Junyi; Ren, Hongyun; Wang, Jiani; Zhang, Xian

2018-03-19

This paper describes the preparation of zwitterion-functionalized polymer microspheres (ZPMs) and their application to simultaneous enrichment of V(V), Cr(III), As(III), Sn(IV), Sb(III) and Hg(II) from environmental water samples. The ZPMs were prepared by emulsion copolymerization of ethyl methacrylate, 2-diethylaminoethyl methacrylate and triethylene glycol dimethyl acrylate followed by modification with 1,3-propanesultone. The components were analyzed by elemental analyses as well as Fourier transform infrared spectroscopy, and the structures were characterized by scanning electron microscopy and transmission electron microscopy. The ZPMs were packed into a mini-column for on-line solid-phase extraction (SPE) of the above metal ions. Following extraction with 40 mM NH 4 NO 3 and 0.5 M HNO 3 solution, the ions were quantified by ICP-MS. Under the optimized conditions, the enrichment factors (from a 40 mL sample) are up to 60 for the ions V(V), As(III), Sb(III) and Hg(II), and 55 for Cr(III) and Sn(IV). The detection limits are 1.2, 3.4, 1.0, 3.7, 2.1 and 1.6 ng L -1 for V(V), Cr(III), As(III), Sn(IV), Sb(III) and Hg(II), respectively, and the relative standard deviations (RSDs) are below 5.2%. The feasibility and accuracy of the method were validated by successfully analyzing six certified reference materials as well as lake, well and river waters. Graphical abstract Zwitterion-functionalized polymer microspheres (ZPMs) were prepared and packed into a mini-column for on-line solid-phase extraction (SPE) via pump 1. Then V(V), Cr(III), As(III), Sn(IV), Sb(III) and Hg(II) ions in environmental waters were eluted and submitted to ICP-MS via pump 2.

Complexation equilibria and spectrophotometric determination of iron(III) with 1-amino-4-hydroxyanthraquinone.

PubMed

Abu-Bakr, M S; Sedaira, H; Hashem, E Y

1994-10-01

The complex equilibria of iron(III) with 1-amino-4-hydroxyanthraquinone (AMHA) were studied spectrophotometrically in 40% (v/v) ethanol and an ionic strength of 0.1M (NaClO(4)). The complexation reactions were demonstrated and characterized using graphical logarithmic analysis of the absorbance-pH graphs. A simple, rapid, selective and sensitive method for the spectrophotometric determination of trace amounts of Fe(III) is developed based on the formation of Fe(AMHA) complex at pH 2.5 (lambda(max) = 640 nm, epsilon approximately = 2.1 x 10(4) L. mol(-1) . cm(-1)) in the presence of a large number of foreign ions. Interferences caused by palladium(II) was masked by the addition of cyanide ions. The method has been applied to the determination of iron in some synthetic samples and polymetallic iron ores.

A useful method for assessing differences of compensatory hypertrophy in the contralateral kidney before and after radical nephrectomy in patients with renal cell carcinoma: ellipsoid formula on computed tomography.

PubMed

Park, Bong Hee; Cho, Kang Jun; Kim, Jung Im; Bae, Sang Rak; Lee, Yong Seok; Kang, Sung Hak; Kim, Joon Chul; Han, Chang Hee

2018-02-01

To investigate the usefulness of the ellipsoid formula for assessing compensatory hypertrophy of the contralateral kidney on pre-operative and post-operative CT in renal cell carcinoma (RCC) patients. We retrospectively identified 389 patients who had radical nephrectomy for RCC between 2011  and 2015. Contrast-enhanced CT was performed within 3 months pre-operative and at 1 year post-operative. The kidney volumes were calculated from CT using the ellipsoid formula. We subdivided patients into three groups based on tumour size (I: ≤4 cm, II: 4-7 cm, III: >7 cm). Volumetric renal parameters were compared and multivariate analyses were performed to determine predictors associated with pre-operative  and post-operative compensatory hypertrophy. Kidney volume calculation using the ellipsoid  method took a median of 51 s. Group III had a significantly larger median pre-operative contralateral renal volume than Groups I and II (I:  140.4, II: 141.6, III: 166.7 ml, p < 0.05). However, the median ratio of post-operative contralateral renal volume change was significantly higher in Groups I and II than Group III (I: 0.36, II: 0.23, III: 0.12, p < 0.001). On multivariate analysis, tumour size revealed the strongest positive association with pre-operative contralateral kidney volume (partial regression coefficient: β = 30.8, >7 cm) and ratio of post-operative contralateral kidney volume change (β  = 0.214, I vs III; β = 0.168, II vs III). Kidney volume calculation for assessing pre- and post-operative compensatory hypertrophy of the contralateral kidney in RCC patients can be easily and rapidly performed from CT images using the ellipsoid formula. Advances in knowledge: The ellipsoid formula allows reliable method for assessing pre-operative and post-operative compensatory hypertrophy of the contralateral kidney in RCC.

Development of a method for total inorganic arsenic analysis using anodic stripping voltammetry and a Au-coated, diamond thin-film electrode.

PubMed

Song, Yang; Swain, Greg M

2007-03-15

We demonstrate that a Au-coated, boron-doped, diamond thin-film electrode provides a sensitive, reproducible, and stable response for total inorganic arsenic (As(III) and As(V)) using differential pulse anodic stripping voltammetry (DPASV). As is preconcentrated with Au on the diamond surface during the deposition step and detected oxidatively during the stripping step. Au deposition was uniform over the electrode surface with a nominal particle size of 23 +/- 5 nm and a particle density of 109 cm-2. The electrode and method were used to measure the As(III) concentration in standard and river water samples. The detection figures of merit were compared with those obtained using conventional Au-coated glassy carbon and Au foil electrodes. The method was also used to determine the As(V) concentration in standard solutions after first being chemically reduced to As(III) with Na2SO3, followed by the normal DPASV determination of As(III). Sharp and symmetric stripping peaks were generally observed for the Au-coated diamond electrode. LODs were 0.005 ppb (S/N = 3) for As(III) and 0.08 ppb (S/N = 3) for As(V) in standard solutions. An As(III) concentration of 0.6 ppb was found in local river water. The relative standard deviation of the As stripping peak current for river water was 1.5% for 10 consecutive measurements and was less than 9.1% over a 10-h period. Excellent electrode response stability was observed even in the presence of up to 5 ppm of added humic acid. In summary, the Au-coated diamond electrode exhibited better performance for total inorganic As analysis than did Au-coated glassy carbon or Au foil electrodes. Clearly, the substrate on which the Au is supported influences the detection figures of merit.

Electronic structure and relative stability of the coherent and semi-coherent HfO2/III-V interfaces

NASA Astrophysics Data System (ADS)

Lahti, A.; Levämäki, H.; Mäkelä, J.; Tuominen, M.; Yasir, M.; Dahl, J.; Kuzmin, M.; Laukkanen, P.; Kokko, K.; Punkkinen, M. P. J.

2018-01-01

III-V semiconductors are prominent alternatives to silicon in metal oxide semiconductor devices. Hafnium dioxide (HfO2) is a promising oxide with a high dielectric constant to replace silicon dioxide (SiO2). The potentiality of the oxide/III-V semiconductor interfaces is diminished due to high density of defects leading to the Fermi level pinning. The character of the harmful defects has been intensively debated. It is very important to understand thermodynamics and atomic structures of the interfaces to interpret experiments and design methods to reduce the defect density. Various realistic gap defect state free models for the HfO2/III-V(100) interfaces are presented. Relative energies of several coherent and semi-coherent oxide/III-V semiconductor interfaces are determined for the first time. The coherent and semi-coherent interfaces represent the main interface types, based on the Ga-O bridges and As (P) dimers, respectively.

Identification and Spectroscopic Characterization of Nonheme Iron(III) Hypochlorite Intermediates.

PubMed

Draksharapu, Apparao; Angelone, Davide; Quesne, Matthew G; Padamati, Sandeep K; Gómez, Laura; Hage, Ronald; Costas, Miquel; Browne, Wesley R; de Visser, Sam P

2015-03-27

Fe III -hypohalite complexes have been implicated in a wide range of important enzyme-catalyzed halogenation reactions including the biosynthesis of natural products and antibiotics and post-translational modification of proteins. The absence of spectroscopic data on such species precludes their identification. Herein, we report the generation and spectroscopic characterization of nonheme Fe III -hypohalite intermediates of possible relevance to iron halogenases. We show that Fe III -OCl polypyridylamine complexes can be sufficiently stable at room temperature to be characterized by UV/Vis absorption, resonance Raman and EPR spectroscopies, and cryo-ESIMS. DFT methods rationalize the pathways to the formation of the Fe III -OCl, and ultimately Fe IV =O, species and provide indirect evidence for a short-lived Fe II -OCl intermediate. The species observed and the pathways involved offer insight into and, importantly, a spectroscopic database for the investigation of iron halogenases.

Precise measurement of charged defects in III-V compounds (supplement 2)

NASA Technical Reports Server (NTRS)

Soest, J. F.

1973-01-01

Experimental methods and related theory which will permit the measurement of low concentrations of vacancies and other defects in III-V compound semiconductors are discussed. Once the nature of these defects has been determined, this information can be incorporated into a transport theory for devices constructed from these materials, and experiments conducted to test the theory. The vacancies and other defects in the III-V compounds are detected by measurement of the nuclear magnetic resonance (NMR) line width. Most of the III-V compounds have at least one isotope with a nuclear quadrupole moment. In a crystal with a cubic crystal field (characteristic of most III-V compounds) there is no quadrupole splitting of the Zeeman resonance line. However, a defect removes the cubic symmetry locally and causes splitting which result in a change of the NMR width. This change can be used to detect the presence of vacancies.

[Cell-ELA-based determination of binding affinity of DNA aptamer against U87-EGFRvIII cell].

PubMed

Tan, Yan; Liang, Huiyu; Wu, Xidong; Gao, Yubo; Zhang, Xingmei

2013-05-01

A15, a DNA aptamer with binding specificity for U87 glioma cells stably overexpressing the epidermal growth factor receptor variant III (U87-EGFRvIII), was generated by cell systematic evolution of ligands by exponential enrichment (cell-SELEX) using a random nucleotide library. Subsequently, we established a cell enzyme-linked assay (cell-ELA) to detect the affinity of A15 compared to an EGFR antibody. We used A15 as a detection probe and cultured U87-EGFRvIII cells as targets. Our data indicate that the equilibrium dissociation constants (K(d)) for A15 were below 100 nmol/L and had similar affinity compared to an EGFR antibody for U87-EGFRvIII. We demonstrated that the cell-ELA was a useful method to determine the equilibrium dissociation constants (K(d)) of aptamers generated by cell-SELEX.

Selective determination of arsenic(III) and arsenic(V) with ammonium pyrrolidinedithiocarbamate, sodium diethyldithiocarbamate and dithizone by means of flameless atomic-absorption spectrophotometry with a carbon-tube atomizer.

PubMed

Kamada, T

The extraction behaviour of arsenic(III) and arsenic(V) with ammonium pyrrolidinedithiocarbamate, sodium diethyldithiocarbamate and dithizone in organic solvents has been investigated by means of nameless atomic-absorption spectrophotometry with a carbon-tube atomizer. The selective extraction of arsenic(III) and differential determination of arsenic(III) and arsenic(V) have been developed. With ammonium pyrrolidinedithiocarbamate and methyl isobutyl ketone or nitrobenzene, when the aqueous phase/solvent volume ratio is 5 and the injection volume in the carbon tube is 20 mul, the sensitivities for 1% absorption are 0.4 and 0.5 part per milliard of arsenic, respectively. The relative standard deviations are ca. 3%. Interference by many metal ions can be prevented by masking with EDTA. The proposed methods are applied satisfactorily for determination of As(III) and As(V) in various types of water.

Induction of protein oxidation in human low density lipoprotein by the photosensitive organic hydroperoxide, N,N'-bis(2-hydroxyperoxy-2-methoxyethyl)-1,4,5,8-naphthalene-tetra-carb oxylic- diimide.

PubMed

Matsugo, S; Yan, L J; Han, D; Packer, L

1995-01-05

We have developed a new molecular probe, N,N'-bis(2-hydroxyperoxy-2-methyoxyethyl)-1,4,5,8-naphthalen e-tetra-carboxylic- diimide (NP-III), that specifically generates hydroxyl radical upon irradiation with longer wavelength ultraviolet light (UVA). Hydroxyl radicals are generated only upon irradiation, thus NP-III is a new controllable hydroxyl radical source. Apolipoprotein (apo-B) of human low density lipoprotein (LDL), and bovine serum alubumin (BSA), were irradiated with UVA in the presence of NP-III and their oxidation was evaluated by two independent methods: assay of protein carbonyl groups and gel electrophoresis. NP-III oxidized apo-B and BSA in a time- and concentration-dependent manner. The results demonstrate that NP-III is a controllable, precise, and potentially tagetable source of hydroxyl radicals with which to induce protein oxidation.

A magnetostructural study of linear NiII MnIII NiII, NiII CrIII NiII and triangular Ni(II)3 species containing (pyridine-2-aldoximato)nickel(II) unit as a building block.

PubMed

Weyhermüller, Thomas; Wagner, Rita; Khanra, Sumit; Chaudhuri, Phalguni

2005-08-07

Three trinuclear complexes, NiII MnIII NiII, NiII CrIII NiII and Ni(II)3 based on (pyridine-2-aldoximato)nickel(II) units are described. Two of them, and , contain metal-centers in linear arrangement, as is revealed by X-ray diffraction. Complex is a homonuclear complex in which the three nickel(II) centers are disposed in a triangular fashion. The compounds were characterized by various physical methods including cyclic voltammetric and variable-temperature (2-290 K) susceptibility measurements. Complexes and display antiferromagnetic exchange coupling of the neighbouring metal centers, while weak ferromagnetic spin exchange between the adjacent Ni II and Cr III ions in is observed. The experimental magnetic data were simulated by using appropriate models.

Intercalation of Coordinatively Unsaturated Fe(III) Ion within Interpenetrated Metal-Organic Framework MOF-5.

PubMed

Holmberg, Rebecca J; Burns, Thomas; Greer, Samuel M; Kobera, Libor; Stoian, Sebastian A; Korobkov, Ilia; Hill, Stephen; Bryce, David L; Woo, Tom K; Murugesu, Muralee

2016-06-01

Coordinatively unsaturated Fe(III) metal sites were successfully incorporated into the iconic MOF-5 framework. This new structure, Fe(III) -iMOF-5, is the first example of an interpenetrated MOF linked through intercalated metal ions. Structural characterization was performed with single-crystal and powder XRD, followed by extensive analysis by spectroscopic methods and solid-state NMR, which reveals the paramagnetic ion through its interaction with the framework. EPR and Mössbauer spectroscopy confirmed that the intercalated ions were indeed Fe(III) , whereas DFT calculations were employed to ascertain the unique pentacoordinate architecture around the Fe(III) ion. Interestingly, this is also the first crystallographic evidence of pentacoordinate Zn(II) within the MOF-5 SBU. This new MOF structure displays the potential for metal-site addition as a framework connector, thus creating further opportunity for the innovative development of new MOF materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

NMR and TRLFS studies of Ln(iii) and An(iii) C5-BPP complexes† †Electronic supplementary information (ESI) available: LIFDI-MS spectra and additional NMR spectra. See DOI: 10.1039/c4sc03103b

PubMed Central

Beele, Björn B.; Geist, Andreas; Müllich, Udo; Kaden, Peter; Panak, Petra J.

2015-01-01

C5-BPP is a highly efficient N-donor ligand for the separation of trivalent actinides, An(iii), from trivalent lanthanides, Ln(iii). The molecular origin of the selectivity of C5-BPP and many other N-donor ligands of the BTP-type is still not entirely understood. We present here the first NMR studies on C5-BPP Ln(iii) and An(iii) complexes. C5-BPP is synthesized with 10% 15N labeling and characterized by NMR and LIFDI-MS methods. 15N NMR spectroscopy gives a detailed insight into the bonding of C5-BPP with lanthanides and Am(iii) as a representative for trivalent actinide cations, revealing significant differences in 15N chemical shift for coordinating nitrogen atoms compared to Ln(iii) complexes. The temperature dependence of NMR chemical shifts observed for the Am(iii) complex indicates a weak paramagnetism. This as well as the observed large chemical shift for coordinating nitrogen atoms show that metal–ligand bonding in Am(C5-BPP)3 has a larger share of covalence than in lanthanide complexes, confirming earlier studies. The Am(C5-BPP)3 NMR sample is furthermore spiked with Cm(iii) and characterized by time-resolved laser fluorescence spectroscopy (TRLFS), yielding important information on the speciation of trace amounts of minor complex species. PMID:29560242

Low Incidence along with Low mRNA Levels of EGFRvIII in Prostate and Colorectal Cancers Compared to Glioblastoma

PubMed Central

Peciak, Joanna; Stec, Wojciech J; Treda, Cezary; Ksiazkiewicz, Magdalena; Janik, Karolina; Popeda, Marta; Smolarz, Maciej; Rosiak, Kamila; Hulas-Bigoszewska, Krystyna; Och, Waldemar; Rieske, Piotr; Stoczynska-Fidelus, Ewelina

2017-01-01

Background: The presence as well as the potential role of EGFRvIII in tumors other than glioblastoma still remains a controversial subject with many contradictory data published. Previous analyses, however, did not consider the level of EGFRvIII mRNA expression in different tumor types. Methods: Appropriately designed protocol for Real-time quantitative reverse-transcription PCR (Real-time qRT-PCR) was applied to analyze EGFRvIII and EGFRWT mRNA expression in 155 tumor specimens. Additionally, Western Blot (WB) analysis was performed for selected samples. Stable cell lines showing EGFRvIII expression (CAS-1 and DK-MG) were analyzed by means of WB, immunocytochemistry (ICC) and fluorescence in situ hybridization (FISH). Results: Our analyses revealed EGFRvIII expression in 27.59% of glioblastomas (8/29), 8.11% of colorectal cancers (3/37), 6.52% of prostate cancers (3/46) and none of breast cancers (0/43). Despite the average relative expression of EGFRvIII varying greatly among tumors of different tissues (approximately 800-fold) or even within the same tissue group (up to 8000-fold for GB), even the marginal expression of EGFRvIII mRNA can be detrimental to cancer progression, as determined by the analysis of stable cell lines endogenously expressing the oncogene. Conclusion: EGFRvIII plays an unquestionable role in glioblastomas with high expression of this oncogene. Our data suggests that EGFRvIII importance should not be underestimated even in tumors with relatively low expression of this oncogene. PMID:28123609

Force Management Methods. Task 1 Report. Current Methods

DTIC Science & Technology

1978-12-01

information about the F/FB-III MCR system is presented in USAF T.O. IF-IlIA-2-1-2 ("F-Ill Service Usage Recorder Program -- Data Collection and Reporting ...34) and T.O. 1F-Ill(B) -2-1-2 ("FB-III Service Usage Program -- Data Collection and Reporting "). The former covers application of the MCR system in F-IIIA...Control Program" NOR 71 -109 "Structural Description Report " NOR 71 -214 "Structural Fatigue Criteria" NOR 76-70 "Structural Fatigue Criteria for Saudi

New coordination compounds of Cr(III) used in leather tanning

NASA Astrophysics Data System (ADS)

Crudu, Marian; Sibiescu, Doina; Rosca, Ioan; Sutiman, Daniel; Vizitiu, Mihaela; Apostolescu, Gabriela

2009-01-01

Some new coordination compounds of Cr(III) using as ligand N-hydroxy - succinimide, were obtained and studied. The combination ratio, central atom: ligand were 1:1; 1:2 and 1:3. The new complex compounds were studied using UV-Vis spectroscopy, conductance and pH measurements. The studies of obtaining and of stability of the new compounds were accomplished in aqueous solutions using methods characteristic for coordination compounds: conductance and pH measurements. The combination ratios and the stability constants were determined with methods characteristic for studies in solutions.

Steric Effect on the Nucleophilic Reactivity of Nickel(III) Peroxo Complexes.

PubMed

Kim, Jalee; Shin, Bongki; Kim, Hyunjeong; Lee, Junhyung; Kang, Joongoo; Yanagisawa, Sachiko; Ogura, Takashi; Masuda, Hideki; Ozawa, Tomohiro; Cho, Jaeheung

2015-07-06

A set of nickel(III) peroxo complexes bearing tetraazamacrocyclic ligands, [Ni(III)(TBDAP)(O2)](+) (TBDAP = N,N'-di-tert-butyl-2,11-diaza[3.3](2,6)pyridinophane) and [Ni(III)(CHDAP)(O2)](+) (CHDAP = N,N'-dicyclohexyl-2,11-diaza[3.3](2,6)pyridinophane), were prepared by reacting [Ni(II)(TBDAP)(NO3)(H2O)](+) and [Ni(II)(CHDAP)(NO3)](+), respectively, with H2O2 in the presence of triethylamine. The mononuclear nickel(III) peroxo complexes were fully characterized by various physicochemical methods, such as UV-vis, electrospray ionization mass spectrometry, resonance Raman, electron paramagnetic resonance, and X-ray analysis. The spectroscopic and structural characterization clearly shows that the NiO2 cores are almost identical where the peroxo ligand is bound in a side-on fashion. However, the different steric properties of the supporting ligands were confirmed by X-ray crystallography, where the CHDAP ligand gives enough space around the Ni core compared to the TBDAP ligand. The nickel(III) peroxo complexes showed reactivity in the oxidation of aldehydes. In the aldehyde deformylation reaction, the nucleophilic reactivity of the nickel(III) peroxo complexes was highly dependent on the steric properties of the macrocyclic ligands, with a reactivity order of [Ni(III)(TBDAP)(O2)](+) < [Ni(III)(CHDAP)(O2)](+). This result provides fundamental insight into the mechanism of the structure (steric)-reactivity relationship of metal peroxo intermediates.

46 CFR 160.176-4 - Incorporation by reference.

Code of Federal Regulations, 2014 CFR

2014-10-01

... and Elongation, Breaking of Woven Cloth; Grab Method, incorporation by reference approved for § 160.176-13. (ii) Method 5132, Strength of Cloth, Tearing; Falling-Pendulum Method, incorporation by reference approved for § 160.176-13. (iii) Method 5134, Strength of Cloth, Tearing; Tongue Method...

46 CFR 160.176-4 - Incorporation by reference.

Code of Federal Regulations, 2013 CFR

2013-10-01

... and Elongation, Breaking of Woven Cloth; Grab Method, incorporation by reference approved for § 160.176-13. (ii) Method 5132, Strength of Cloth, Tearing; Falling-Pendulum Method, incorporation by reference approved for § 160.176-13. (iii) Method 5134, Strength of Cloth, Tearing; Tongue Method...

Global Regulatory Functions of the Staphylococcus aureus Endoribonuclease III in Gene Expression

PubMed Central

Lioliou, Efthimia; Sharma, Cynthia M.; Caldelari, Isabelle; Helfer, Anne-Catherine; Fechter, Pierre; Vandenesch, François; Vogel, Jörg; Romby, Pascale

2012-01-01

RNA turnover plays an important role in both virulence and adaptation to stress in the Gram-positive human pathogen Staphylococcus aureus. However, the molecular players and mechanisms involved in these processes are poorly understood. Here, we explored the functions of S. aureus endoribonuclease III (RNase III), a member of the ubiquitous family of double-strand-specific endoribonucleases. To define genomic transcripts that are bound and processed by RNase III, we performed deep sequencing on cDNA libraries generated from RNAs that were co-immunoprecipitated with wild-type RNase III or two different cleavage-defective mutant variants in vivo. Several newly identified RNase III targets were validated by independent experimental methods. We identified various classes of structured RNAs as RNase III substrates and demonstrated that this enzyme is involved in the maturation of rRNAs and tRNAs, regulates the turnover of mRNAs and non-coding RNAs, and autoregulates its synthesis by cleaving within the coding region of its own mRNA. Moreover, we identified a positive effect of RNase III on protein synthesis based on novel mechanisms. RNase III–mediated cleavage in the 5′ untranslated region (5′UTR) enhanced the stability and translation of cspA mRNA, which encodes the major cold-shock protein. Furthermore, RNase III cleaved overlapping 5′UTRs of divergently transcribed genes to generate leaderless mRNAs, which constitutes a novel way to co-regulate neighboring genes. In agreement with recent findings, low abundance antisense RNAs covering 44% of the annotated genes were captured by co-immunoprecipitation with RNase III mutant proteins. Thus, in addition to gene regulation, RNase III is associated with RNA quality control of pervasive transcription. Overall, this study illustrates the complexity of post-transcriptional regulation mediated by RNase III. PMID:22761586

Effects of Al(III) and Nano-Al13 Species on Malate Dehydrogenase Activity

PubMed Central

Yang, Xiaodi; Cai, Ling; Peng, Yu; Li, Huihui; Chen, Rong Fu; Shen, Ren Fang

2011-01-01

The effects of different aluminum species on malate dehydrogenase (MDH) activity were investigated by monitoring amperometric i-t curves for the oxidation of NADH at low overpotential using a functionalized multi-wall nanotube (MWNT) modified glass carbon electrode (GCE). The results showed that Al(III) and Al13 can activate the enzymatic activity of MDH, and the activation reaches maximum levels as the Al(III) and Al13 concentration increase. Our study also found that the effects of Al(III) and Al13 on the activity of MDH depended on the pH value and aluminum speciation. Electrochemical and circular dichroism spectra methods were applied to study the effects of nano-sized aluminum compounds on biomolecules. PMID:22163924

Effects of Al(III) and nano-Al13 species on malate dehydrogenase activity.

PubMed

Yang, Xiaodi; Cai, Ling; Peng, Yu; Li, Huihui; Chen, Rong Fu; Shen, Ren Fang

2011-01-01

The effects of different aluminum species on malate dehydrogenase (MDH) activity were investigated by monitoring amperometric i-t curves for the oxidation of NADH at low overpotential using a functionalized multi-wall nanotube (MWNT) modified glass carbon electrode (GCE). The results showed that Al(III) and Al(13) can activate the enzymatic activity of MDH, and the activation reaches maximum levels as the Al(III) and Al(13) concentration increase. Our study also found that the effects of Al(III) and Al(13) on the activity of MDH depended on the pH value and aluminum speciation. Electrochemical and circular dichroism spectra methods were applied to study the effects of nano-sized aluminum compounds on biomolecules.

Fe(III)-solar light induced degradation of diethyl phthalate (DEP) in aqueous solutions.

PubMed

Mailhot, G; Sarakha, M; Lavedrine, B; Cáceres, J; Malato, S

2002-11-01

The degradation of diethyl phthalate (DEP) photoinduced by Fe(III) in aqueous solutions has been investigated under solar irradiation in the compound parabolic collector reactor at Plataforma Solar de Almeria. Hydroxyl radicals *OH, responsible of the degradation, are formed via an intramolecular photoredox process in the excited state of Fe(III) aquacomplexes. The primary step of the reaction is mainly due to the attack of *OH radicals on the aromatic ring. For prolonged irradiations DEP and its photoproducts are completely mineralized due to the regeneration of the absorbing species and the continuous formation of *OH radicals that confers a catalytic aspect to the process. Consequently, the degradation photoinduced by Fe(III) could be an efficient method of DEP removal from water.

Accurate prediction of secreted substrates and identification of a conserved putative secretion signal for type III secretion systems

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

Samudrala, Ram; Heffron, Fred; McDermott, Jason E.

2009-04-24

The type III secretion system is an essential component for virulence in many Gram-negative bacteria. Though components of the secretion system apparatus are conserved, its substrates, effector proteins, are not. We have used a machine learning approach to identify new secreted effectors. The method integrates evolutionary measures, such as the pattern of homologs in a range of other organisms, and sequence-based features, such as G+C content, amino acid composition and the N-terminal 30 residues of the protein sequence. The method was trained on known effectors from Salmonella typhimurium and validated on a corresponding set of effectors from Pseudomonas syringae, aftermore » eliminating effectors with detectable sequence similarity. The method was able to identify all of the known effectors in P. syringae with a specificity of 84% and sensitivity of 82%. The reciprocal validation, training on P. syringae and validating on S. typhimurium, gave similar results with a specificity of 86% when the sensitivity level was 87%. These results show that type III effectors in disparate organisms share common features. We found that maximal performance is attained by including an N-terminal sequence of only 30 residues, which agrees with previous studies indicating that this region contains the secretion signal. We then used the method to define the most important residues in this putative secretion signal. Finally, we present novel predictions of secreted effectors in S. typhimurium, some of which have been experimentally validated, and apply the method to predict secreted effectors in the genetically intractable human pathogen Chlamydia trachomatis. This approach is a novel and effective way to identify secreted effectors in a broad range of pathogenic bacteria for further experimental characterization and provides insight into the nature of the type III secretion signal.« less

Determination of arsenic speciation in sulfidic waters by Ion Chromatography Hydride-Generation Atomic Fluorescence Spectrometry (IC-HG-AFS).

PubMed

Keller, Nicole S; Stefánsson, Andri; Sigfússon, Bergur

2014-10-01

A method for the analysis of arsenic species in aqueous sulfide samples is presented. The method uses an ion chromatography system connected with a Hydride-Generation Atomic Fluorescence Spectrometer (IC-HG-AFS). With this method inorganic As(III) and As(V) species in water samples can be analyzed, including arsenite (HnAs(III)O3(n-3)), thioarsenite (HnAs(III)S3(n-3)), arsenate (HnAs(V)O4(n-3)), monothioarsenate (HnAs(V)SO3(n-3)), dithioarsenate (HnAs(V)S2O2(n-3)), trithioarsenate (HnAs(V)S3O(n-3)) and tetrathioarsenate (HnAs(V)S4(n-3)). The peak identification and retention times were determined based on standard analysis of the various arsenic compounds. The analytical detection limit was ~1-3 µg L(-1) (LOD), depending on the quality of the baseline. This low detection limit makes this method also applicable to discriminate between waters meeting the drinking water standard of max. 10 µg L(-1) As, and waters that do not meet this standard. The new method was successfully applied for on-site determination of arsenic species in natural sulfidic waters, in which seven species were unambiguously identified. Copyright © 2014 Elsevier B.V. All rights reserved.

Higher Education: Handbook of Theory and Research. Volumes III [and] IV.

ERIC Educational Resources Information Center

Smart, John C., Ed.

Two volumes of a handbook on theory and research in higher education are presented. The 11 papers included in Volume III are as follows: "Qualitative Research Methods in Higher Education" (R. Crowson); "Bricks and Mortar: Architecture and the Study of Higher Education" (J. Thelin and J. Yankovich); "Enrollment Demand Models and Their Policy Uses…

Challenges of Implementing a Top-Down Curriculum Innovation in English Language Teaching: Perspectives of Form Iii English Language Teachers in Kenya

ERIC Educational Resources Information Center

Okoth, Teresa A.

2016-01-01

This study investigated the challenges Form III English language teachers face when implementing the revised integrated English language curriculum. A mixed-method descriptive design was used in Eldoret East SubCounty in Kenya. Data was collected through questionnaires, interviews and reflective conversations. Cluster, purposive and random…

Measurement Properties and Classification Accuracy of Two Spanish Parent Surveys of Language Development for Preschool-Age Children

ERIC Educational Resources Information Center

Guiberson, Mark; Rodriguez, Barbara L.

2010-01-01

Purpose: To describe the concurrent validity and classification accuracy of 2 Spanish parent surveys of language development, the Spanish Ages and Stages Questionnaire (ASQ; Squires, Potter, & Bricker, 1999) and the Pilot Inventario-III (Pilot INV-III; Guiberson, 2008a). Method: Forty-eight Spanish-speaking parents of preschool-age children…

An Analytical Chemistry Experiment in Simultaneous Spectrophotometric Determination of Fe(III) and Cu(II) with Hexacyanoruthenate(II) Reagent.

ERIC Educational Resources Information Center

Mehra, M. C.; Rioux, J.

1982-01-01

Experimental procedures, typical observations, and results for the simultaneous analysis of Fe(III) and Cu(II) in a solution are discussed. The method is based on selective interaction between the two ions and potassium hexacyanoruthenate(II) in acid solution involving no preliminary sample preparations. (Author/JN)

Luminescence recognition of different organophosphorus pesticides by the luminescent Eu(III)-pyridine-2,6-dicarboxylic acid probe.

PubMed

Azab, Hassan A; Duerkop, Axel; Anwar, Z M; Hussein, Belal H M; Rizk, Moustafa A; Amin, Tarek

2013-01-08

Luminescence quenching of a novel long lived Eu(III)-pyridine-2,6-dicarboxylic acid probe of 1:2 stoichiometric ratio has been studied in 0.10 volume fraction ethanol-water mixture at pH 7.5 (HEPES buffer) in the presence of the organophosphorus pesticides chlorfenvinphos (P1), malathion (P2), azinphos (P3), and paraxon ethyl (P4). The luminescence intensity of Eu(III)-(PDCA)(2) probe decreases as the concentration of the pesticide increases. It was observed that the quenching due to P3 and P4 proceeds via both diffusional and static quenching processes. Direct methods for the determination of the pesticides under investigation have been developed using the luminescence quenching of Eu(III)-pyridine-2,6-dicarboxylic acid probe in solution. The linear range for determination of the selected pesticides is 1.0-35.0 μM. The detection limits were 0.24-0.55 μM for P3, P4, and P1 and 2.5 μM for P2, respectively. The binding constants (K), and thermodynamic parameters of the OPs with Eu(III)-(PDCA)(2) were evaluated. Positive and negative values of entropy (ΔS) and enthalpy (ΔH) changes for Eu(III)-(PDCA)(2)-P1 ternary complex were calculated. As the waters in this study do not contain the above mentioned OPs over the limit detectable by the method, a recovery study was carried out after the addition of the adequate amounts of the organophosphorus pesticides under investigation. Copyright © 2012 Elsevier B.V. All rights reserved.

Nano sponge Mn₂O ₃ as a new adsorbent for the preconcentration of Pd(II) and Rh(III) ions in sea water, wastewater, rock, street sediment and catalytic converter samples prior to FAAS determinations.

PubMed

Yavuz, Emre; Tokalıoğlu, Serife; Sahan, Halil; Patat, Saban

2014-10-01

In this study, a nano sponge Mn2O3 adsorbent was synthesized and was used for the first time. Various parameters affecting the recovery values of Pd(II) and Rh(III) were examined. The tolerance limits (≥ 90 %) for both Pd(II) and Rh(III) ions were found to be 75,000 mg L(-1) Na(I), 75,000 mg L(-1) K(I), 50,000 mg L(-1) Mg(II) and 50,000 mg L(-1) Ca(II). A 30s contact time was enough for both adsorption and elution. A preconcentration factor of 100 was obtained by using 100mg of the nano sponge Mn2O3. The reusability of the adsorbent was 120 times. Adsorption capacities for Pd(II) and Rh(III) were found to be 42 and 6.2 mg g(-1), respectively. The detection limits were 1.0 µg L(-1) for Pd(II) and 0.37 µg L(-1) for Rh(III) and the relative standard deviations (RSD, %) were found to be ≤ 2.5%. The method was validated by analyzing the standard reference material, SRM 2556 (Used Auto Catalyst Pellets) and spiked real samples. The optimized method was applied for the preconcentration of Pd(II) and Rh(III) ions in water (sea water and wastewater), rock, street sediment and catalytic converter samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Comparison of LSS-IV and LISS-III+LISS-IV merged data for classification of crops

NASA Astrophysics Data System (ADS)

Hebbar, R.; Sesha Sai, M. V. R.

2014-11-01

Resourcesat-1 satellite with its unique capability of simultaneous acquisition of multispectral images at different spatial resolutions (AWiFS, LISS-III and LISS-IV MX / Mono) has immense potential for crop inventory. The present study was carried for selection of suitable LISS-IV MX band for data fusion and its evaluation for delineation different crops in a multi-cropped area. Image fusion techniques namely intensity hue saturation (IHS), principal component analysis (PCA), brovey, high pass filter (HPF) and wavelet methods were used for merging LISS-III and LISS-IV Mono data. The merged products were evaluated visually and through universal image quality index, ERGAS and classification accuracy. The study revealed that red band of LISS-IV MX data was found to be optimal band for merging with LISS-III data in terms of maintaining both spectral and spatial information and thus, closely matching with multispectral LISS-IVMX data. Among the five data fusion techniques, wavelet method was found to be superior in retaining image quality and higher classification accuracy compared to commonly used methods of IHS, PCA and Brovey. The study indicated that LISS-IV data in mono mode with wider swath of 70 km could be exploited in place of 24km LISS-IVMX data by selection of appropriate fusion techniques by acquiring monochromatic data in the red band.

Field method for the determination of hexavalent chromium by ultrasonication and strong anion-exchange solid-phase extraction.

PubMed

Wang, J; Ashley, K; Marlow, D; England, E C; Carlton, G

1999-03-01

A simple, fast, sensitive, and economical field method was developed and evaluated for the determination of hexavalent chromium (CrVI) in environmental and workplace air samples. By means of ultrasonic extraction in combination with a strong anion-exchange solid-phase extraction (SAE-SPE) technique, the filtration, isolation, and determination of CrVI in the presence of trivalent chromium (CrIII) and potential interferents was achieved. The method entails (1) ultrasonication in basic ammonium buffer solution to extract CrVI from environmental matrixes; (2) SAE-SPE to separate CrVI from CrIII and interferences; (3) elution/acidification of the eluate; (4) complexation of chromium with 1,5-diphenylcarbazide; and (5) spectrophotometric determination of the colored chromium-diphenylcarbazone complex. Several critical parameters were optimized in order to effect the extraction of both soluble (K2CrO4) and insoluble (PbCrO4) forms of CrVI without inducing CrIII oxidation or CrVI reduction. The method allowed for the dissolution and purification of CrVI from environmental and workplace air sample matrixes for up to 24 samples simultaneously in less than 90 min (including ultrasonication). The results demonstrated that the method was simple, fast, quantitative, and sufficiently sensitive for the determination of occupational exposures of CrVI. The method is applicable for on-site monitoring of CrVI in environmental and industrial hygiene samples.

[Efficiency of combined methods of hemorroid treatment using hal-rar and laser destruction].

PubMed

Rodoman, G V; Kornev, L V; Shalaeva, T I; Malushenko, R N

2017-01-01

To develop the combined method of treatment of hemorrhoids with arterial ligation under Doppler control and laser destruction of internal and external hemorrhoids. The study included 100 patients with chronic hemorrhoids stage II and III. Combined method of HAL-laser was used in study group, HAL RAR-technique in control group 1 and closed hemorrhoidectomy with linear stapler in control group 2. Сomparative evaluation of results in both groups was performed. Combined method overcomes the drawbacks of traditional surgical treatment and limitations in external components elimination which are inherent for HAL-RAR. Moreover, it has a higher efficiency in treating of hemorrhoids stage II-III compared with HAL-RAR and is equally safe and well tolerable for patients. This method does not increase the risk of recurrence, reduces incidence of complications and time of disability.

Evaluation of the effect of three innovative recyling methods on the shear bond strength of stainless steel brackets-an in vitro study.

PubMed

Gupta, Neeraj; Kumar, Dilip; Palla, Aparna

2017-04-01

Orthodontists are commonly faced with the decision of what to do with debonded or inaccurately positioned brackets. An economical option to this dilemma is to recycle the brackets. Many recycling methods have been proposed, but the optimal bond strength of these recycled brackets needs further evaluation. Objectives: To evaluate and compare the effect of three recycling methods: (i) Sandblasting (ii) Sandblasting / direct flaming (iii) Sandblasting /direct flaming /acid bath solution on shear bond strength (SBS) of stainless steel brackets. Eighty human premolars were bonded with premolar stainless steel brackets as per manufacturer's instructions. The teeth were divided into 4 groups (n=20): Recycling and initial debonding was not done in Control group (Group I). After initial bonding, the brackets in the rest of the three experimental groups were debonded and recycled by following methods: (i) Sandblasting (Group II) (ii) Sandblasting /direct flaming (Group III) (iii) Sandblasting /direct flaming /acid bath solution (Group IV). Further the recycled brackets were bonded. The specimens were then subjected to testing in a Universal machine. The evaluation of the variation of the shear bond strength (SBS) among test groups was done using one-way ANOVA test and inter-experimental group comparison was done by Newman-Keuls multiple post hoc procedure. Group I (8.6510±1.3943MPa) showed the highest bond strength followed by Group II (5.0185±0.9758MPa), Group IV (2.30±0.65MPa) and Group III (2.0455± 0.6196MPa). Statistically significant variations existed in the shear bond strength (SBS) in all groups analyzed except between Group III and Group IV. The following conclusions were drawn from the study: 1. Shear bond strength of new brackets is significantly higher than the recycled brackets. 2. Brackets sandblasted with 90µm aluminium oxide particle air-abrasion showed significantly higher shear bond strength compared to direct flaming/sandblasting and direct flaming/sandblasting/acid bath solution. 3. Sandblasting with 90µm aluminium oxide particle air-abrasion is the simplest, most efficient and hence, the preferred method of recycling debonded brackets. Key words: Orthodontic bracket, recycling, shear bond strength.

Total inorganic arsenic detection in real water samples using anodic stripping voltammetry and a gold-coated diamond thin-film electrode.

PubMed

Song, Yang; Swain, Greg M

2007-06-12

An accurate method for total inorganic arsenic determination in real water samples was developed using differential pulse anodic stripping voltammetry (DPASV) and a Au-coated boron-doped diamond thin-film electrode. Keys to the method are the use of a conducting diamond platform and solid phase extraction for sample preparation. In the method, the As(III) present in the sample is first detected by DPASV. The As(V) present is then reduced to As(III) by reaction with Na2SO3 and this is followed by a second detection of As(III) by DPASV. Interfering metal ions (e.g., Cu(II)) that cause decreased electrode response sensitivity for arsenic in real samples are removed by solid phase extraction as part of the sample preparation. For example, Cu(II) caused a 30% decrease in the As stripping peak current at a solution concentration ratio of 3:1 (Cu(II)/As(III)). This loss was mitigated by passage of the solution through a Chelex 100 cation exchange resin. After passage, only a 5% As stripping current response loss was seen. The effect of organic matter on the Au-coated diamond electrode response for As(III) was also evaluated. Humic acid at a 5 ppm concentration caused only a 9% decrease in the As stripping peak charge for Au-coated diamond. By comparison, a 50% response decrease was observed for Au foil. Clearly, the chemical properties of the diamond surface in the vicinity of the metal deposits inhibit molecular adsorption on at least some of the Au surface. The method provided reproducible and accurate results for total inorganic arsenic in two contaminated water samples provided by the U.S. Bureau of Reclamation. The total inorganic As concentration in the two samples, quantified by the standard addition method, was 23.2+/-2.9 ppb for UV plant influent water and 16.4+/-0.9 ppb for Well 119 water (n=4). These values differed from the specified concentrations by less than 4%.

Synergistic liquid-liquid extractive spectrophotometric determination of gold(III) using 1-(2',4'-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-thiol.

PubMed

Kamble, Ganesh S; Kolekar, Sanjay S; Han, Sung H; Anuse, Mansing A

2010-05-15

Synergistic liquid-liquid extractive spectrophotometric determination of gold(III) using 1-(2',4'-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydro pyrimidine-2-thiol [2',4'-dinitro APTPT] has been described. Equal volumes (5cm(3)) of the 2',4'-dinitro APTPT (0.02molL(-1)) in the presence of pyridine (0.5molL(-1)) form an orange-red coloured ternary complex with gold(III) of molar ratio 1:1:1 at pH 1.8-2.4 with 5min of shaking. The absorbance of coloured organic layer in 1,2-dichloroethane is measured spectrophotometrically at 445nm against reagent blank. A pronounced synergism has been observed by the binary mixture of 2',4'-dinitro APTPT and pyridine, which shows that the enhancement in the absorbance is observed in the presence of pyridine by the adduct formation in the organic phase. Beer's law was obeyed in the concentration range 2.5-20.0microgmL(-1), with molar absorptivity and Sandell's sensitivity values of 8.7x10(3)dm(3)mol(-1)cm(-1) and 0.023microgcm(-2) respectively. A repetition of the method was checked by finding relative standard deviation (R.S.D.) (n=10) which was 0.17%. The composition of the gold(III)-2',4'-dinitro APTPT-pyridine adduct was established by slope analysis, molar ratio and Job's method. The ternary complex was stable for more than 48h. The influence of various factors such as pH, 2',4'-dinitro APTPT concentration, solvent and pyridine on the degree of complexation has been established. A number of foreign ions tested for their interferences and use of suitable masking agents wherever necessary are tabulated, which show that selectivity of the method has been enhanced. The method is successfully employed for the determination of gold(III) in binary, synthetic mixtures and ayurvedic samples. The reliability of the method is assured by inter-comparison of experimental values, using an atomic absorption spectrometer.

Chimeric antigen receptor containing ICOS signaling domain mediates specific and efficient antitumor effect of T cells against EGFRvIII expressing glioma.

PubMed

Shen, Chan-Juan; Yang, Yu-Xiu; Han, Ethan Q; Cao, Na; Wang, Yun-Fei; Wang, Yi; Zhao, Ying-Ying; Zhao, Li-Ming; Cui, Jian; Gupta, Puja; Wong, Albert J; Han, Shuang-Yin

2013-05-09

Adoptive transfer of chimeric antigen receptor (CAR)-modified T cells appears to be a promising immunotherapeutic strategy. CAR combines the specificity of antibody and cytotoxicity of cytotoxic T lymphocytes, enhancing T cells' ability to specifically target antigens and to effectively kill cancer cells. Recent efforts have been made to integrate the costimulatory signals in the CAR to improve the antitumor efficacy. Epidermal growth factor receptor variant III (EGFRvIII) is an attractive therapeutic target as it frequently expresses in glioma and many other types of cancers. Our current study aimed to investigate the specific and efficient antitumor effect of T cells modified with CAR containing inducible costimulator (ICOS) signaling domain. A second generation of EGFRvIII/CAR was generated and it contained the EGFRvIII single chain variable fragment, ICOS signaling domain and CD3ζ chain. Lentiviral EGFRvIII/CAR was prepared and human CD3+ T cells were infected by lentivirus encoding EGFRvIII/CAR. The expression of EGFRvIII/CAR on CD3+ T cells was confirmed by flow cytometry and Western blot. The functions of EGFRvIII/CAR+ T cells were evaluated using in vitro and in vivo methods including cytotoxicity assay, cytokine release assay and xenograft tumor mouse model. Chimeric EGFRvIIIscFv-ICOS-CD3ζ (EGFRvIII/CAR) was constructed and lentiviral EGFRvIII/CAR were made to titer of 106 TU/ml. The transduction efficiency of lentiviral EGFRvIII/CAR on T cells reached around 70% and expression of EGFRvIII/CAR protein was verified by immunoblotting as a band of about 57 kDa. Four hour 51Cr release assays demonstrated specific and efficient cytotoxicity of EGFRvIII/CAR+ T cells against EGFRvIII expressing U87 cells. A robust increase in the IFN-γ secretion was detected in the co-culture supernatant of the EGFRvIII/CAR+ T cells and the EGFRvIII expressing U87 cells. Intravenous and intratumor injection of EGFRvIII/CAR+ T cells inhibited the in vivo growth of the EGFRvIII expressing glioma cells. Our study demonstrates that the EGFRvIII/CAR-modified T cells can destroy glioma cells efficiently in an EGFRvIII specific manner and release IFN-γ in an antigen dependent manner. The specific recognition and effective killing activity of the EGFRvIII-directed T cells with ICOS signaling domain lays a foundation for us to employ such approach in future cancer treatment.

PPP1R12A Copy Number Is Associated with Clinical Outcomes of Stage III CRC Receiving Oxaliplatin-Based Chemotherapy

PubMed Central

Zhang, Chenbo; Li, Ajian; Li, Huaguang; Peng, Kangsheng; Wei, Qing; Lin, Moubin; Liu, Zhanju; Yin, Lu; Li, Jianwen

2015-01-01

Aim. To investigate the correlation between PPP1R12A gene copy number and clinical outcomes of oxaliplatin-based regimen in stage III colorectal cancer (CRC). Methods. A total of 139 paraffin-embedded tissue samples of stage III CRC patients who received oxaliplatin-based treatment after radical surgery were recruited. Genomic DNA was extracted and purified from paraffin-embedded sections. Quantitative PCR methods were used to detect the relative copy number (RCN) of PPP1R12A. Results. Statistical analysis demonstrated that low PPP1R12A RCN was associated with poor RFS (HR = 2.186, 95% CI: 1.293–3.696; P = 0.003) and OS (HR = 2.782, 95% CI: 1.531–5.052; P < 0.001). Additionally, when patients were stratified according to subgroups of stage III and tumor location, poor RFS and OS were also observed in the low PPP1R12A RCN group with significance (RFS: IIIB HR = 2.870, P < 0.001; colon HR = 1.910, P = 0.037; OS: IIIB HR = 3.527, P < 0.001; IIIC HR = 2.662, P = 0.049; rectum HR = 4.229, P = 0.002). Conclusion. Our findings suggest the copy number of PPP1R12A can independently predict recurrence and overall survival of stage III colorectal cancer patients receiving oxaliplatin-based chemotherapy. PMID:26113782

Dual-Enhanced Photocatalytic Activity of Fe-Deposited Titanate Nanotubes Used for Simultaneous Removal of As(III) and As(V).

PubMed

Liu, Wen; Zhao, Xiao; Borthwick, Alistair G L; Wang, Yanqi; Ni, Jinren

2015-09-09

Fe-deposited titanate nanotubes (Fe-TNTs) with high photocatalytic activity and adsorptive performance were synthesized through a one-step hydrothermal method. Initial As(III) oxidation followed by As(V) adsorption by Fe-TNTs could simultaneously remove these two toxic pollutants from aqueous solutions. The apparent rate constant value for photo-oxidation of As(III) under UV irradiation by Fe-TNTs was almost 250 times that of unmoidified TNTs. Under visible light, the Fe-TNTs also exhibited enhanced photocatalytic activity after Fe was deposited. Fe3+ located in the interlayers of TNTs acted as temporary electron- or hole-trapping sites, and attached α-Fe2O3 played the role of a charge carrier for electrons transferred from TNTs. These two effects inhibited electron-hole pair recombination thus promoting photocatalysis. Moreover, the As(V) adsorptive performance of Fe-TNTs also improved, owing to the presence of additional adsorption sites, α-Fe2O3, as well as increased pHPZC. Furthermore, Fe-TNTs exhibited good photocatalytic and adsorptive performace even after 5 reuse cycles. The present tests, concerning an initial As(III) photocatalysis and subsequent As(V) adsorption process, highlight the feasibility and importance of Fe used to modify TNTs. This study proposes a feasible method to simultaneously remove As(III) and As(V) from contaminated water using a novel Ti-based nanomaterial.

Solid phase extraction and spectrophotometric determination of Au(III) with 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine.

PubMed

Hu, Qiufen; Chen, Xiubin; Yang, Xiangjun; Huang, Zhangjie; Chen, Jing; Yang, Guangyu

2006-04-01

A new chromogenic reagent, 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine (HNATR) was synthesized. A highly sensitive, selective and rapid method for the determination microg l(-1) level of Au(III) based on the rapid reaction of Au(III) with HNATR and the solid phase extraction of the colored complex with a reversed phase polymer-based C(18) cartridge have been developed. The HNATR reacted with Au(III) to form a red complex of a molar ratio 1:2 (Au(III) to HNATR) in the presence of 0.05 - 0.5 mol l(-1) of phosphoric acid solution and emulsifier-OP medium. This complex was enriched by the solid phase extraction with a polymer-based C(18) cartridge. The enrichment factor of 100 was achieved. The molar absorptivity of the complex is 1.37 x 10(5) l mol(-1) cm(-1) at 520 nm in the measured solution. The system obeys Beer's law in the range of 0.01 - 3 microg ml(-1). The relative standard deviation for eleven replicates sample of 0.5 microg l(-1) level is 2.18%. The detection limit, based on the three times of standard deviation is 0.02 microg l(-1) in the original sample. This method was applied to the determination of gold in water and ore with good results.

A cascade signal amplification strategy for sensitive and label-free DNA detection based on Exo III-catalyzed recycling coupled with rolling circle amplification.

PubMed

Liu, Xingti; Xue, Qingwang; Ding, Yongshun; Zhu, Jing; Wang, Lei; Jiang, Wei

2014-06-07

A sensitive and label-free fluorescence assay for DNA detection has been developed based on cascade signal amplification combining exonuclease III (Exo III)-catalyzed recycling with rolling circle amplification. In this assay, probe DNA hybridized with template DNA was coupled onto magnetic nanoparticles to prepare a magnetic bead-probe (MNB-probe)-template complex. The complex could hybridize with the target DNA, which transformed the protruding 3' terminus of template DNA into a blunt end. Exo III could then digest template DNA, liberating the MNB-probe and target DNA. The intact target DNA then hybridized with other templates and released more MNB-probes. The liberated MNB-probe captured the primer, circular DNA and then initiated the rolling circle amplification (RCA) reaction, realizing a cascade signal amplification. Using this cascade amplification strategy, a sensitive DNA detection method was developed which was superior to many existing Exo III-based signal amplification methods. Moreover, N-methyl mesoporphyrin IX, which had a pronounced structural selectivity for the G-quadruplex, was used to combine with the G-quadruplex RCA products and generate a fluorescence signal, avoiding the need for any fluorophore-label probes. The spike and recovery experiments in a human serum sample indicated that our assay also had great potential for DNA detection in real biological samples.

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

USGS Publications Warehouse

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

2007-01-01

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

Determination of Sulfonamide Residues in Food by Capillary Zone Electrophoresis with On-Line Chemiluminescence Detection Based on an Ag(III) Complex

PubMed Central

Dai, Tingting; Duan, Jie; Li, Xinghua; Xu, Xiangdong; Shi, Hongmei; Kang, Weijun

2017-01-01

The presence of sulfonamide (SA) residues in foods is largely due to the raising of animals with sulfonamide antibiotics added or polluted feedstuff. In this paper, a sensitive method was developed for the determination of the residues of three sulfonamides in animal-derived food; the SAs include sulfadimidine (SDD), sulfadiazine (SDZ), and sulfathiazole (STZ). The method is based on capillary zone electrophoresis (CE) with online chemiluminescence (CL) detection, using an Ag(III) complex as an oxidant. These SAs have an inhibiting effect on the Ag(III)–luminol CL reaction. The electrophoretic buffer is 12.0 mM sodium borate. Under a set of optimized conditions, the linear ranges for the detections were found to be 10.0–200 µg·mL−1 for SDD and SDZ, and 2.0–50.0 µg·mL−1 for STZ. The detection limits were 2.75, 3.14, and 0.65 µg·mL−1 for SDD, SDZ, and STZ, respectively. Relative standard deviations (RSD) for the peak heights were between 2.1% and 2.8% (n = 7). The proposed method was used in the analysis of the SAs in samples from pork meat, chicken meat, and milk, showing satisfactory detection results. A reaction mechanism was also proposed for the Ag(III)–luminol–SA CL reactions. The method has potential applications for the monitoring of residue levels of the three SAs in food, providing food safety data. PMID:28621728

Method of removing oxidized contaminants from water

DOEpatents

Amonette, James E.; Fruchter, Jonathan S.; Gorby, Yuri A.; Cole, Charles R.; Cantrell, Kirk J.; Kaplan, Daniel I.

1998-01-01

The present invention is a method for removing oxidized contaminant(s) from water. More specifically, the invention has the steps of contacting water containing the oxidized contaminant(s) with a layered aluminosilicate having Fe(II). The aluminosilicate may contain naturally occurring Fe(II), or the Fe(II) may be produced by reducing Fe(III) that is initially present. Reduction may be either by exposure to a chemical or biological reductant. Contacting the water containing oxidized contaminant(s) may be by (1) injection of Fe(II)-containing layered aluminosilicate, via a well, into a saturated zone where it is likely to intercept the contaminated water; (2) injection of contaminated water into a vessel containing the Fe(II)-bearing layered aluminosilicate; and (3) first reducing Fe(III) in the layered aluminosilicate to Fe(II) by injection of a biological or chemical reductant, into an aquifer or vessel having sufficient Fe(III)-bearing aluminosilicate to produce the necessary Fe(II).

Method of removing oxidized contaminants from water

DOEpatents

Amonette, J.E.; Fruchter, J.S.; Gorby, Y.A.; Cole, C.R.; Cantrell, K.J.; Kaplan, D.I.

1998-07-21

The present invention is a method for removing oxidized contaminant(s) from water. More specifically, the invention has the steps of contacting water containing the oxidized contaminant(s) with a layered aluminosilicate having Fe(II). The aluminosilicate may contain naturally occurring Fe(II), or the Fe(II) may be produced by reducing Fe(III) that is initially present. Reduction may be either by exposure to a chemical or biological reductant. Contacting the water containing oxidized contaminant(s) may be by (1) injection of Fe(II)-containing layered aluminosilicate, via a well, into a saturated zone where it is likely to intercept the contaminated water; (2) injection of contaminated water into a vessel containing the Fe(II)-bearing layered aluminosilicate; and (3) first reducing Fe(III) in the layered aluminosilicate to Fe(II) by injection of a biological or chemical reductant, into an aquifer or vessel having sufficient Fe(III)-bearing aluminosilicate to produce the necessary Fe(II). 8 figs.

Method of carbon chain extension using novel aldol reaction

DOEpatents

Silks, Louis A; Gordon, John C; Wu, Ruilan; Hanson, Susan Kloek

2013-07-30

Method of producing C.sub.8-C.sub.15 hydrocarbons. comprising providing a ketone starting material; providing an aldol starting material comprising chloromethylfurfural; mixing the ketone starting material and the aldol starting material in a reaction in the presence of a proline-containing catalyst selected from the group consisting of Zn(Pro).sub.2, Yb(Pro).sub.3, and combinations thereof, or a catalyst having one of the structures (I), (II) or (III), and in the presence of a solvent, wherein the solvent comprises water and is substantially free of organic solvents, where (I), (II) and (III) respectively are: ##STR00001## where R.sub.1 is a C.sub.1-C.sub.6 alkyl moiety, X=(OH) and n=2. ##STR00002## In (III), X may be CH.sub.2, sulfur or selenium, M may be Zn, Mg, or a lanthanide, and R.sub.1 and R.sub.2 each independently may be a methyl, ethyl, phenyl moiety.

Method of carbon chain extension using novel aldol reaction

DOEpatents

Silks, Louis A; Gordon, John C; Wu, Ruilan; Hangson, Susan Kloek

2013-08-13

Method of producing C.sub.8-C.sub.15 hydrocarbons comprising providing a ketone starting material; providing an aldol starting material comprising hydroxymethylfurfural; mixing the ketone starting material and the aldol starting material in a reaction in the presence of a proline-containing catalyst selected from the group consisting of Zn(Pro).sub.2, Yb(Pro).sub.2, and combinations thereof, or a catalyst having one of the structures (I), (II) or (III), and in the presence of a solvent, wherein the solvent comprises water and is substantially free of organic solvents, where (I), (II) and (III) respectively are: ##STR00001## where R.sub.1 is a C.sub.1-C.sub.6 alkyl moiety, X=(OH) and n=2. ##STR00002## In (III), X may be CH.sub.2, sulfur or selenium, M may be Zn, Mg, or a lanthanide, and R.sub.1 and R.sub.2 each independently may be a methyl, ethyl, phenyl moiety.

Interobserver reliability of a "Standardized Psychiatric Examination" (SPE) for case ascertainment (DSM-III).

PubMed

Romanoski, A J; Nestadt, G; Chahal, R; Merchant, A; Folstein, M F; Gruenberg, E M; McHugh, P R

1988-02-01

The authors describe the Standardized Psychiatric Examination (SPE), a new method for conducting psychiatric examinations in both clinical and research settings that preserves the clinical method. The SPE provides a consistent replicable format for eliciting and recording psychiatric history, signs, and symptoms without perturbing the patient-clinician interaction. By means of the SPE, the clinician can formulate diagnoses using DSM-III or ICD-9 criteria and yet generate CATEGO profiles derived from the Present State Examination, 9th edition. Psychiatrists using the SPE demonstrated high interrater reliability in ascertaining individual psychopathological symptoms (Kappa range, 0.55 to 1.0) and in making DSM-III diagnoses (Kappa range, 0.79 to 1.0) among a sample of study subjects (N = 43) drawn from both a psychiatric inpatient population and a large community sample of nonpatients from the Epidemiological Catchment Area (ECA) study. The implications of the SPE for clinical practice and for research are discussed.

Arsenite and arsenate removal from wastewater using cationic polymer-modified waste tyre rubber.

PubMed

Imyim, Apichat; Sirithaweesit, Thitayati; Ruangpornvisuti, Vithaya

2016-01-15

Waste tyre rubber (WTR) granulate was modified with a cationic polymer, poly(3-acrylamidopropyl)trimethylammonium chloride (p(APTMACl)). The resulting WTR/p(APTMACl) was utilized for the adsorption of arsenite, As(III) and arsenate, As(V) from aqueous medium in both batch and column methods. The level of adsorption increased gradually with increasing monomer concentration and contact time. The adsorption behavior obeyed the Freundlich model, and the rate of adsorption could be predicted by employing the pseudo-second order model. In the column method, As(V) could be adsorbed onto the sorbent more effectively than As(III). Remarkable desorption of As(III) and As(V) (99 and 92%, respectively) from the adsorbent was achieved using 0.10 M HCl as eluent. An approach of evaluation of adsorption capacity uncertainty is proposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Semiclassical Calculation of Reaction Rate Constants for Homolytical Dissociations

NASA Technical Reports Server (NTRS)

Cardelino, Beatriz H.

2002-01-01

There is growing interest in extending organometallic chemical vapor deposition (OMCVD) to III-V materials that exhibit large thermal decomposition at their optimum growth temperature, such as indium nitride. The group III nitrides are candidate materials for light-emitting diodes and semiconductor lasers operating into the blue and ultraviolet regions. To overcome decomposition of the deposited compound, the reaction must be conducted at high pressures, which causes problems of uniformity. Microgravity may provide the venue for maintaining conditions of laminar flow under high pressure. Since the selection of optimized parameters becomes crucial when performing experiments in microgravity, efforts are presently geared to the development of computational OMCVD models that will couple the reactor fluid dynamics with its chemical kinetics. In the present study, we developed a method to calculate reaction rate constants for the homolytic dissociation of III-V compounds for modeling OMCVD. The method is validated by comparing calculations with experimental reaction rate constants.

[Ultrasound duplex scanning of head and neck vessels with the aim of preoperational preparation of the patients with inherent microtia of the III degree].

PubMed

Chkadua, T Z; Kuz'mina, I V; Ramazanova, Iu I

2010-01-01

For surgical treatment of patients with inherent microtia of the III degree we use one stage method of otoplasty with silicone implant and parietotemporal fascial flap. In order to receive most full picture of the status of superficial temporal artery and its branches the additional diagnostic study is necessary. Method of ultrasound duplex scanning let to study any vessel in real time regimen under monitor screen control. Received by us results of ultrasound duplex scanning of superficial temporal artery branches in patients with inherent microtia of the III degree let us to conclude about the status of the vessel wall, to determine diameter and vessel occlusion, to evaluate and measure blood flow parameters. It is diagnostically necessary criteria for answering the question about flap vitality and in such a way let to avoid possible complications.

Structural Characterization of Am(III)- and Pu(III)-DOTA Complexes.

PubMed

Audras, Matthieu; Berthon, Laurence; Berthon, Claude; Guillaumont, Dominique; Dumas, Thomas; Illy, Marie-Claire; Martin, Nicolas; Zilbermann, Israel; Moiseev, Yulia; Ben-Eliyahu, Yeshayahu; Bettelheim, Armand; Cammelli, Sebastiano; Hennig, Christoph; Moisy, Philippe

2017-10-16

The complexation of 1,4,7,10-tetrazacyclodecane-1,4,7,10-tetraacetic acid (DOTA) ligand with two trivalent actinides (Am 3+ and Pu 3+ ) was investigated by UV-visible spectrophotometry, NMR spectroscopy, and extended X-ray absorption fine structure in conjunction with computational methods. The complexation process of these two cations is similar to what has been previously observed with lanthanides(III) of similar ionic radius. The complexation takes place in different steps and ends with the formation of a (1:1) complex [(An(III)DOTA)(H 2 O)] - , where the cation is bonded to the nitrogen atoms of the ring, the four carboxylate arms, and a water molecule to complete the coordination sphere. The formation of An(III)-DOTA complexes is faster than the Ln(III)-DOTA systems of equivalent ionic radius. Furthermore, it is found that An-N distances are slightly shorter than Ln-N distances. Theoretical calculations showed that the slightly higher affinity of DOTA toward Am over Nd is correlated with slightly enhanced ligand-to-metal charge donation arising from oxygen and nitrogen atoms.

Deferiprone, a non-toxic reagent for determination of iron in samples via sequential injection analysis

NASA Astrophysics Data System (ADS)

Pragourpun, Kraivinee; Sakee, Uthai; Fernandez, Carlos; Kruanetr, Senee

2015-05-01

We present for the first time the use of deferiprone as a non-toxic complexing agent for the determination of iron by sequential injection analysis in pharmaceuticals and food samples. The method was based on the reaction of Fe(III) and deferiprone in phosphate buffer at pH 7.5 to give a Fe(III)-deferiprone complex, which showed a maximum absorption at 460 nm. Under the optimum conditions, the linearity range for iron determination was found over the range of 0.05-3.0 μg mL-1 with a correlation coefficient (r2) of 0.9993. The limit of detection and limit of quantitation were 0.032 μg mL-1 and 0.055 μg mL-1, respectively. The relative standard deviation (%RSD) of the method was less than 5.0% (n = 11), and the percentage recovery was found in the range of 96.0-104.0%. The proposed method was satisfactorily applied for the determination of Fe(III) in pharmaceuticals, water and food samples with a sampling rate of 60 h-1.

40 CFR 63.805 - Performance test methods.

Code of Federal Regulations, 2011 CFR

2011-07-01

... alternative method for determining the VHAP content of the coating. In the event of any inconsistency between... Collection of Coating and Ink Samples for VOC Content Analysis by Reference Method 24 and Reference Method... (see § 63.801); (iii) Use any alternative protocol and test method provided they meet either the...

DFT-based molecular modeling and vibrational study of the La(III) complex of 3,3'-(benzylidene)bis(4-hydroxycoumarin).

PubMed

Mihaylov, Tzvetan; Trendafilova, Natasha; Georgieva, Ivelina

2008-05-01

Molecular modeling of the La(III) complex of 3,3'-(benzylidene)bis(4-hydroxycoumarin) (PhDC) was performed using density functional theory (DFT) methods at B3LYP/6-31G(d) and BP86/TZP levels. Both Stuttgart-Dresden effective core potential and ZORA approximation were applied to the La(III) center. The electron density distribution and the nucleophilic centers of the deprotonated ligand PhDC(2-) in a solvent environment were estimated on the basis of Hirshfeld atomic charges, electrostatic potential values at the nuclei, and Nalewajski-Mrozek bond orders. In accordance with the empirical formula La(PhDC)(OH)(H(2)O), a chain structure of the complex was simulated by means of two types of molecular fragment: (1) two La(III) cations bound to one PhDC(2-) ligand, and (2) two PhDC(2-) ligands bound to one La(III) cation. Different orientations of PhDC(2-), OH(-) and H(2)O ligands in the La(III) complexes were investigated using 20 possible [La(PhDC(2-))(2)(OH)(H(2)O)](2-) fragments. Energy calculations predicted that the prism-like structure based on "tail-head" cis-LML2 type binding and stabilized via HO...HOH intramolecular hydrogen bonds is the most probable structure for the La(III) complex. The calculated vibrational spectrum of the lowest energy La(III) model fragment is in very good agreement with the experimental IR spectrum of the complex, supporting the suggested ligand binding mode to La(III) in a chain structure, namely, every PhDC(2-) interacts with two La(III) cations through both carbonylic and both hydroxylic oxygens, and every La(III) cation binds four oxygen atoms of two different PhDC(2-).

Batch sorption-desorption of As(III) from waste water by magnetic palm kernel shell activated carbon using optimized Box-Behnken design

NASA Astrophysics Data System (ADS)

Anyika, Chinedum; Asri, Nur Asilayana Mohd; Majid, Zaiton Abdul; Jaafar, Jafariah; Yahya, Adibah

2017-12-01

In this study, we converted activated carbon (AC) into magnetic activated carbon (MAC), which was established to have removed arsenic (III) from wastewater. Arsenic (III) is a toxic heavy metal which is readily soluble in water and can be detrimental to human health. The MAC was prepared by incorporating Fe3O4 into the AC by using Fe3O4 extracted from a ferrous sulfate solution, designated: magnetic palm kernel shell from iron suspension (MPKSF). Batch experiments were conducted using two methods: (1) one-factor-at-a-time and (2) Box-Behnken statistical analysis. Results showed that the optimum conditions resulted in 95% of As(III) removal in the wastewater sample. The adsorption data were best fitted to the Langmuir isotherm. The adsorption of As(III) onto the MPKSF was confirmed by energy dispersive X-ray spectrometry analysis which detected the presence of As(III) of 0.52% on the surface of the MPKSF. The Fourier transform infrared spectroscopy analysis of the MPKSF-As presented a peak at 573 cm-1, which was assigned to M-O (metal-oxygen) bending, indicating the coordination of As(III) with oxygen through the formation of inner-sphere complexation, thereby indicating a covalent bonding between the MPKSF functional groups and As(III). The findings suggested that the MPKSF exhibited a strong capacity to efficiently remove As(III) from wastewater, while the desorption studies showed that the As(III) was rigidly bound to the MPKSF thereby eliminating the possibility of secondary pollution.

Tobacco industry influence on the definition of tobacco related disorders by the American Psychiatric Association

PubMed Central

Neuman, M; Bitton, A; Glantz, S

2005-01-01

Objective: The Diagnostic and statistical manual of mental disorders, third edition (DSM-III), published by the American Psychiatric Association (APA) in 1980, included the first official definitions by the APA of tobacco dependence and tobacco withdrawal. Tobacco industry efforts to influence the DSM-III were investigated. Method: Searches of previously secret tobacco industry documents, primarily the University of California San Francisco Legacy Tobacco Documents Library and British American Tobacco collections. Additional information was collected through discussions with editors of DSM-III, and library and general internet searches. Results: The tobacco companies regarded the inclusion of tobacco dependence as a diagnosis in DSM-III as an adverse event. It worked to influence the content of the DSM-III and its impact following publication. These efforts included public statements and private lobbying of DSM-III editors and high ranking APA officers by prominent US psychiatrists with undisclosed ties to the tobacco industry. Following publication of DSM-III, tobacco companies contracted with two US professors of psychiatry to organise a conference and publish a monograph detailing controversies surrounding DSM-III. Conclusions: The tobacco industry and its allies lobbied to narrow the definition of tobacco dependence in serial revisions of DSM-III. Following publication of DSM-III, the industry took steps to try to mitigate its impact. These actions mirror industry tactics to influence medical research and policy in various contexts worldwide. Such tactics slow the spread of a professional and public understanding of smoking and health that otherwise would reduce smoking, smoking induced disease, and tobacco company profits. PMID:16183984

Reflection mass spectrometry technique for monitoring and controlling composition during molecular beam epitaxy

DOEpatents

Brennan, T.M.; Hammons, B.E.; Tsao, J.Y.

1992-12-15

A method for on-line accurate monitoring and precise control of molecular beam epitaxial growth of Groups III-III-V or Groups III-V-V layers in an advanced semiconductor device incorporates reflection mass spectrometry. The reflection mass spectrometry is responsive to intentional perturbations in molecular fluxes incident on a substrate by accurately measuring the molecular fluxes reflected from the substrate. The reflected flux is extremely sensitive to the state of the growing surface and the measurements obtained enable control of newly forming surfaces that are dynamically changing as a result of growth. 3 figs.

Effect of oxidation state and ionic strength on sorption of actinides (Th, U, Np, Am) to geologic media [Abstract and References Only

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

Dittrich, Timothy M.; Richmann, Michael K.; Reed, Donald T.

2015-10-30

The degree of conservatism in the estimated sorption partition coefficients (K ds) used in a performance assessment model is being evaluated based on a complementary batch and column method. The main focus of this work is to investigate the role of ionic strength, solution chemistry, and oxidation state (III-VI) in actinide sorption to dolomite rock. Based on redox conditions and solution chemistry expected at the WIPP, possible actinide species include Pu(III), Pu(IV), U(IV), U(VI), Np(IV), Np(V), Am(III), and Th(IV).

Reflection mass spectrometry technique for monitoring and controlling composition during molecular beam epitaxy

DOEpatents

Brennan, Thomas M.; Hammons, B. Eugene; Tsao, Jeffrey Y.

1992-01-01

A method for on-line accurate monitoring and precise control of molecular beam epitaxial growth of Groups III-III-V or Groups III-V-V layers in an advanced semiconductor device incorporates reflection mass spectrometry. The reflection mass spectrometry is responsive to intentional perturbations in molecular fluxes incident on a substrate by accurately measuring the molecular fluxes reflected from the substrate. The reflected flux is extremely sensitive to the state of the growing surface and the measurements obtained enable control of newly forming surfaces that are dynamically changing as a result of growth.

Reductive reactivity of iron(III) oxides in the east china sea sediments: characterization by selective extraction and kinetic dissolution.

PubMed

Chen, Liang-Jin; Zhu, Mao-Xu; Yang, Gui-Peng; Huang, Xiang-Li

2013-01-01

Reactive Fe(III) oxides in gravity-core sediments collected from the East China Sea inner shelf were quantified by using three selective extractions (acidic hydroxylamine, acidic oxalate, bicarbonate-citrate buffered sodium dithionite). Also the reactivity of Fe(III) oxides in the sediments was characterized by kinetic dissolution using ascorbic acid as reductant at pH 3.0 and 7.5 in combination with the reactive continuum model. Three parameters derived from the kinetic method: m 0 (theoretical initial amount of ascorbate-reducible Fe(III) oxides), k' (rate constant) and γ (heterogeneity of reactivity), enable a quantitative characterization of Fe(III) oxide reactivity in a standardized way. Amorphous Fe(III) oxides quantified by acidic hydroxylamine extraction were quickly consumed in the uppermost layer during early diagenesis but were not depleted over the upper 100 cm depth. The total amounts of amorphous and poorly crystalline Fe(III) oxides are highly available for efficient buffering of dissolved sulfide. As indicated by the m 0, k' and γ, the surface sediments always have the maximum content, reactivity and heterogeneity of reactive Fe(III) oxides, while the three parameters simultaneously downcore decrease, much more quickly in the upper layer than at depth. Albeit being within a small range (within one order of magnitude) of the initial rates among sediments at different depths, incongruent dissolution could result in huge discrepancies of the later dissolution rates due to differentiating heterogeneity, which cannot be revealed by selective extraction. A strong linear correlation of the m 0 at pH 3.0 with the dithionite-extractable Fe(III) suggests that the m 0 may represent Fe(III) oxide assemblages spanning amorphous and crystalline Fe(III) oxides. Maximum microbially available Fe(III) predicted by the m 0 at pH 7.5 may include both amorphous and a fraction of other less reactive Fe(III) phases.

Reductive Reactivity of Iron(III) Oxides in the East China Sea Sediments: Characterization by Selective Extraction and Kinetic Dissolution

PubMed Central

Chen, Liang-Jin; Zhu, Mao-Xu; Yang, Gui-Peng; Huang, Xiang-Li

2013-01-01

Reactive Fe(III) oxides in gravity-core sediments collected from the East China Sea inner shelf were quantified by using three selective extractions (acidic hydroxylamine, acidic oxalate, bicarbonate-citrate buffered sodium dithionite). Also the reactivity of Fe(III) oxides in the sediments was characterized by kinetic dissolution using ascorbic acid as reductant at pH 3.0 and 7.5 in combination with the reactive continuum model. Three parameters derived from the kinetic method: m 0 (theoretical initial amount of ascorbate-reducible Fe(III) oxides), k′ (rate constant) and γ (heterogeneity of reactivity), enable a quantitative characterization of Fe(III) oxide reactivity in a standardized way. Amorphous Fe(III) oxides quantified by acidic hydroxylamine extraction were quickly consumed in the uppermost layer during early diagenesis but were not depleted over the upper 100 cm depth. The total amounts of amorphous and poorly crystalline Fe(III) oxides are highly available for efficient buffering of dissolved sulfide. As indicated by the m 0, k′ and γ, the surface sediments always have the maximum content, reactivity and heterogeneity of reactive Fe(III) oxides, while the three parameters simultaneously downcore decrease, much more quickly in the upper layer than at depth. Albeit being within a small range (within one order of magnitude) of the initial rates among sediments at different depths, incongruent dissolution could result in huge discrepancies of the later dissolution rates due to differentiating heterogeneity, which cannot be revealed by selective extraction. A strong linear correlation of the m 0 at pH 3.0 with the dithionite-extractable Fe(III) suggests that the m 0 may represent Fe(III) oxide assemblages spanning amorphous and crystalline Fe(III) oxides. Maximum microbially available Fe(III) predicted by the m 0 at pH 7.5 may include both amorphous and a fraction of other less reactive Fe(III) phases. PMID:24260377

Evaluation of the effect of three innovative recyling methods on the shear bond strength of stainless steel brackets-an in vitro study

PubMed Central

Kumar, Dilip; Palla, Aparna

2017-01-01

Background Orthodontists are commonly faced with the decision of what to do with debonded or inaccurately positioned brackets. An economical option to this dilemma is to recycle the brackets. Many recycling methods have been proposed, but the optimal bond strength of these recycled brackets needs further evaluation. Objectives: To evaluate and compare the effect of three recycling methods: (i) Sandblasting (ii) Sandblasting / direct flaming (iii) Sandblasting /direct flaming /acid bath solution on shear bond strength (SBS) of stainless steel brackets. Material and Methods Eighty human premolars were bonded with premolar stainless steel brackets as per manufacturer’s instructions. The teeth were divided into 4 groups (n=20): Recycling and initial debonding was not done in Control group (Group I). After initial bonding, the brackets in the rest of the three experimental groups were debonded and recycled by following methods: (i) Sandblasting (Group II) (ii) Sandblasting /direct flaming (Group III) (iii) Sandblasting /direct flaming /acid bath solution (Group IV). Further the recycled brackets were bonded. The specimens were then subjected to testing in a Universal machine. The evaluation of the variation of the shear bond strength (SBS) among test groups was done using one-way ANOVA test and inter-experimental group comparison was done by Newman-Keuls multiple post hoc procedure. Results Group I (8.6510±1.3943MPa) showed the highest bond strength followed by Group II (5.0185±0.9758MPa), Group IV (2.30±0.65MPa) and Group III (2.0455± 0.6196MPa). Statistically significant variations existed in the shear bond strength (SBS) in all groups analyzed except between Group III and Group IV. Conclusions The following conclusions were drawn from the study: 1. Shear bond strength of new brackets is significantly higher than the recycled brackets. 2. Brackets sandblasted with 90µm aluminium oxide particle air-abrasion showed significantly higher shear bond strength compared to direct flaming/sandblasting and direct flaming/sandblasting/acid bath solution. 3. Sandblasting with 90µm aluminium oxide particle air-abrasion is the simplest, most efficient and hence, the preferred method of recycling debonded brackets. Key words:Orthodontic bracket, recycling, shear bond strength. PMID:28469821

Operative treatment of acute acromioclavicular dislocations Rockwood III and V-Comparative study between K-wires combined with FiberTape(®) vs. TightRope System(®).

PubMed

Vrgoč, G; Japjec, M; Jurina, P; Gulan, G; Janković, S; Šebečić, B; Starešinić, M

2015-11-01

Acromioclavicular (AC) joint dislocations usually occur in a young active population as a result of a fall on the shoulder. Rockwood divided these dislocations into six types. Optimal treatment is still a matter of discussion. Many operative techniques have been developed, but the main choice is between open and minimally-invasive arthroscopic procedures. The aim of this study was to compare two different surgical methods on two groups of patients to find out which method is superior in terms of benefit to the patient. The methods were evaluated through objective and subjective scores, with a focus on complications and material costs. A retrospective two-centre study was conducted in patients with acute AC joint dislocation Rockwood types III and V. The two methods conducted were an open procedure using K-wires combined with FiberTape(®) (Arthrex, Naples, USA) (Group 1) and an arthroscopic procedure using the TightRope System(®) (Arthrex, Naples, USA) (Group 2). Groups underwent procedures during a two-year period. Diagnosis was based on the clinical and radiographic examination of both AC joints. Surgical treatment and rehabilitation were performed. Sixteen patients were included in this study: Group 1 comprised 10 patients, all male, average age 41.6 years (range 17-64 years), Rockwood type III (eight patients) and Rockwood type V (two patients); Group 2 had six patients, one female and five male, average age 37.8 years (range 18-58 years), Rockwood type III (two patients) and Rockwood type V (four patients). Time from injury to surgery was shorter and patients needed less time to return to daily activities in Group 1. Duration of the surgical procedure was shorter in Group 2 compared with Group 1. Complications of each method were noted. According to the measured scores and operative outcome between dislocation Rockwood type III and V, no significant difference was found. Implant material used in Group 2 was 4.7 times more expensive than that used in Group 1. Both methods offer many advantages with satisfying evaluated scores. K-wires with FiberTape(®) offer a shorter period for complete recovery and a significantly more cost-effective outcome, whereas the TightRope System(®) offers shorter operative procedure, better cosmetic result and avoidance of intraoperative fluoroscopy. Copyright © 2015 Elsevier Ltd. All rights reserved.

Luminescent Properties of Eu(III) Chelates on Metal Nanorods

PubMed Central

Zhang, Jian; Fu, Yi; Ray, Krishanu; Wang, Yuan; Lakowicz, Joseph. R.

2013-01-01

In this article, we report the change of optical properties for europium chelates on silver nanorods by near-field interactions. The silver rods were fabricated in a seed-growth method followed by depositing thin layers of silica on the surfaces. The europium chelates were physically absorbed in the silica layers on the silver rods. The silver rods were observed to exhibit two plasmon absorption bands from longitudinal and transverse directions, respectively, centered at 394 and 675 nm, close to absorption and emission bands from the Eu(III) chelates. As a result, the immobilized Eu(III) chelates on the silver rods should have strong interactions with the silver nanorods and lead to greatly improved optical properties. The Eu–Ag rod complexes were observed to have enhanced emission intensity up to 240-fold in comparison with the Eu(III) chelates in the metal-free silica templates. This enhancement is much larger than the value for the Eu(III) chelates on the gold rods or silver spheres indicating the presence of stronger interactions for the Eu(III) chelates with the silver rods. The interactions of Eu(III) chelates with the silver rods were also proven by extremely reduced lifetime. Moreover, the Eu–Ag rod complexes exhibited a polarized emission, which was also due to strong interactions of the Eu(III) chelates with the silver rods. All of these features may promise that the Eu(III)–Ag rod complexes have great potential for use as fluorescence imaging agents in biological assays. PMID:24363816

Ion Mobility Measurements of Multianionic Metalloporphyrin Dimers: Structural Changes Induced by Countercation Exchange

NASA Astrophysics Data System (ADS)

Schneider, Erik; Brendle, Katrina; Jäger, Patrick; Weis, Patrick; Kappes, Manfred M.

2018-04-01

We present gas-phase structures of dimers of MnIII and FeIII meso-tetra(4-sulfonatophenyl)porphyrin multianions with various amounts of sodium and hydrogen counterions. The structural assignments are achieved by combining mass spectrometry, ion mobility measurements, quantum chemical calculations, and trajectory method collision cross section calculations. For a common charge state, we observe significant topological variations in the dimer structures of [(MTPPS)2+nX](6-n)- (M=MnIII, FeIII; X=H, Na; n = 1-3) induced by replacing hydrogen counterions by sodium. For sodium, the dimer structures are much more compact, a finding that can be rationalized by the stronger interactions of the sodium cations with the anionic sulfonic acid groups of the porphyrins as compared to hydrogen. [Figure not available: see fulltext.

Immunochemical characterization of the "native" type III polysaccharide of group B Streptococcus

PubMed Central

1976-01-01

The type III polysaccharide of -roup B Streptococcus has been isolated and purified by a method that employs washing of intact cells at neutral pH. That the polysaccharide prepared by this procedure is the "native" type III antigen is suggested by its molecular size in excess of 10(6) daltons, its degradation by acid and heat treatment to a fragment with immunologic characteristics of the classical HCl antigen, and its type-specific serologic activity. The type III polysaccharide in native form contains sialic acid, galactose, glucose, glucosamine, heptose, and mannose. It is acidic in nature, is resistant to neuramindiase degradation, contains no O-acetyl groups, and does not share antigenic determinants with capsular type K1 antigen of Escherichia coli or Group B polysaccharide antigen of Neiserria meningitidis. PMID:55450

Fine typing of methicillin-resistant Staphylococcus aureus isolates using direct repeat unit and staphylococcal interspersed repeat unit typing methods.

PubMed

Ho, Cheng-Mao; Ho, Mao-Wang; Li, Chi-Yuan; Lu, Jang-Jih

2015-08-01

Methicillin-resistant Staphylococcus aureus (MRSA) typing is an important epidemiologic tool for monitoring trends and preventing outbreaks. However, the efficiency of various MRSA typing methods for each SCCmec MRSA isolate is rarely evaluated. A total of 157 MRSA isolates from four different regions in Taiwan were typed with five different molecular methods, including SCCmec typing, multilocus sequence typing (MLST), spa typing, mec-associated direct repeat unit (dru) copy number determination, and staphylococcal interspersed repeat unit (SIRU) profiling. There were four SCCmec types, eight MLST types, 15 spa types, 11 dru types, and 31 SIRU profiles. The most common type determined by each molecular typing method was SCCmec III (115 isolates, 73.2%), ST239 (99 isolates, 63.1%), t037 (107 isolates, 68.2%), 14 dru copies (76 isolates, 48.4%), and SIRU profile 3013722 (102 isolates, 65%), respectively. When using the combination of MLST, spa typing, and dru copy number, ST5-t002-4 (n = 8), ST239-t037-14 (n = 68), ST59-t437-9 (n = 9), and ST59-t437-11 (n = 6) were found to be the most common types of SCCmec types II (n = 9), III (n = 115), IV (n = 21), and VT (n = 11) isolates, respectively. SCCmec type III isolates were further classified into 11 dru types. Of the 21 SCCmec type IV isolates, 14 SIRU profiles were found. Seven SIRU patterns were observed in the 11 SCCmec type VT isolates. Different typing methods showed a similar Hunter-Gaston discrimination index among the 157 MRSA isolates. However, dru and SIRU typing methods had a better discriminatory power for SCCmec type III and SCCmec types IV and VT isolates, respectively, suggesting that dru and SIRU can be used to further type these isolates. Copyright © 2013. Published by Elsevier B.V.

[Studies on the triterpenoids of Cyclocarya paliurus (Batal.) Iljinsk].

PubMed

Shu, Rengeng; Liu, Yufeng; Chen, Jie; Shu, Jicheng

2005-07-01

Three triterpenes (I-II) were obtained from the leaves of Cyclocarya paliurus (Batal.) Iljinsk. By means of physicochemical and spectral methods, the structures of the three triterpenes were identified as oleanolic acid (I), ursolic acid (II) and epikatonic acid (III) respectively. All of the three triterpenes were isolated for the first time from the plant of Cyclocarya paliurus (Batal.) Iljinsk.

APPLICATION OF SAMPLE PRE-OXIDATION OF ARSENITE IN HUMAN URINE PRIOR TO SPECIATON VIA ON-LINE PHOTO-OXIDATION WITH MEMBRANE HYDRIDE GENRATION AND ICP-MS DETECTION

EPA Science Inventory

A pre-oxidation procedure which converts arsenite (AS(III)) to arsenate (As(VVV)) was investigated in urinary arsenic speciation prior to on-line photo-oxidation hydride-generation with ICP-MS detection. This sample pre-oxidation method eliminates As(III) and As(V) preservation c...

[Injuries of the acromioclavicular joint].

PubMed

Meeder, P J; Dannöhl, C

1988-07-01

The injuries of the acromio-clavicular joint require a differentiated diagnosis and treatment. The classification of the acromio-clavicular dislocations from grade I to grade III according to Tossy is proved. The diagnosis of a complete acromio-clavicular dislocation (Tossy III) is an indication for a surgical repair. Many and different methods are reported in the literature. 178 patients with a fresh acromio-clavicular dislocation (Typ Tossy II and III) were treated at the BG-Unfallklinik Tübingen from 1970 to 1987 by suturing the ligaments, inserting pins across the joint and tension wire bending. In old cases with Tossy III dislocation of the acromio-clavicular joint an oblique osteotomy combined with the reduction of the clavicle is recommended as a method of choice. The results of these procedures and there possible intra- and postoperative complications are reported. The incision along the clavicle quite often gives scar problems. Therefore the advantages of an arched incision across the acromio-clavicular joint is pointed out. Because of there biomechanical relationship fractures in the lateral third of the clavicle are similar to dislocations of the acromio-clavicular joint. The classification of these fractures according to Jäger, Buschle and Breitner allows a differentiated management of these lesions.

Golgi-Colonnier method: correlation of the degree of chromium reduction and pH change with quality of staining.

PubMed

Angulo, A; Merchán, J A; Molina, M

1994-03-01

We examined the role of chromium reduction in the Golgi-Colonnier method, correlating the quality of neuronal impregnation with the levels of hexavalent (CrVI) and trivalent (CrIII) chromium in the tissue and in the chromation fluid (CF). The concentrations of both chromium species were assessed by measuring spectrophotometrically the CrVI before and after oxidizing the sample and by calculating the ratio of CrVI to total chromium (chromium ratio, CrR). The CrR was almost identical in the tissue and the CF, decreasing exponentially during chromation due to a progressive consumption of CrVI to form CrIII. Satisfactory cell impregnation was obtained only when the CrR was 0.45-0.7, regardless of other factors. The CrR values could be accurately predicted by the pH increase of the CF; this increase has proven to be a most reliable criterion to decide the endpoint of the chromation process. The dependence of cell staining on the [CrIII], together with the well-known ability of this species to bridge proteins, suggests that the key event for cell impregnation is the cross-linking of neuronal proteins by CrIII polymers.

Separation, preconcentration and inductively coupled plasma-mass spectrometric (ICP-MS) determination of thorium(IV), titanium(IV), iron(III), lead(II) and chromium(III) on 2-nitroso-1-naphthol impregnated MCI GEL CHP20P resin.

PubMed

Aydin, Funda Armagan; Soylak, Mustafa

2010-01-15

A simple and effective method is presented for the separation and preconcentration of Th(IV), Ti(IV), Fe(III), Pb(II) and Cr(III) by solid phase extraction on 2-nitroso-1-naphthol impregnated MCI GEL CHP20P resin prior to their inductively coupled plasma-mass spectrometric determinations. The influence of analytical parameters including pH of the aqueous solution, flow rates of sample and eluent solutions and sample volume on the quantitative recoveries of analyte ions was investigated. Matrix effects caused by the presence of alkali, earth alkali and some metal ions in the analyzed solutions were investigated. The presented solid phase extraction method was applied to BCR-144R Sewage Sludge (domestic origin), BCR-141R Calcareous Loam Soil, NIST 1568a Rice Flour and NIST 1577b Bovine Liver certified reference materials (CRMs) for the determination of analyte ions and the results were in good agreement with the certified values. The separation procedure presented was also applied to the various natural water samples collected from Turkey with satisfactory results.

CE of phytosiderophores and related metal species in plants.

PubMed

Xuan, Yue; Scheuermann, Enrico B; Meda, Anderson R; Jacob, Peter; von Wirén, Nicolaus; Weber, Günther

2007-10-01

Phytosiderophores (PS) and the closely related substance nicotianamine (NA) are key substances in metal uptake into graminaceous plants. Here, the CE separation of these substances and related metal species is demonstrated. In particular, the three PS 2'-deoxymugineic acid (DMA), mugineic acid (MA), and 3-epi-hydroxymugineic acid (epi-HMA), and NA, are separated using MES/Tris buffer at pH 7.3. Moreover, three Fe(III) species of the different PS are separated without any stability problems, which are often present in chromatographic analyses. Also divalent metal species of Cu, Ni, and Zn with the ligands DMA and NA are separated with the same method. By using a special, zwitterionic CE capillary, even the separation of two isomeric Fe(III) chelates with the ligand ethylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid (EDDHA) is possible (i.e., meso-Fe(III)-EDDHA and rac-Fe(III)-EDDHA), and for fast separations of NA and respective divalent and trivalent metal species, a polymer CE microchip with suppressed EOF is described. The proposed CE method is applicable to real plant samples, and enables to detect changes of metal species (Cu-DMA, Ni-NA), which are directly correlated to biological processes.

Genomic organization, sequence characterization and expression analysis of Tenebrio molitor apolipophorin-III in response to an intracellular pathogen, Listeria monocytogenes.

PubMed

Noh, Ju Young; Patnaik, Bharat Bhusan; Tindwa, Hamisi; Seo, Gi Won; Kim, Dong Hyun; Patnaik, Hongray Howrelia; Jo, Yong Hun; Lee, Yong Seok; Lee, Bok Luel; Kim, Nam Jung; Han, Yeon Soo

2014-01-25

Apolipophorin III (apoLp-III) is a well-known hemolymph protein having a functional role in lipid transport and immune response of insects. We cloned full-length cDNA encoding putative apoLp-III from larvae of the coleopteran beetle, Tenebrio molitor (TmapoLp-III), by identification of clones corresponding to the partial sequence of TmapoLp-III, subsequently followed with full length sequencing by a clone-by-clone primer walking method. The complete cDNA consists of 890 nucleotides, including an ORF encoding 196 amino acid residues. Excluding a putative signal peptide of the first 20 amino acid residues, the 176-residue mature apoLp-III has a calculated molecular mass of 19,146Da. Genomic sequence analysis with respect to its cDNA showed that TmapoLp-III was organized into four exons interrupted by three introns. Several immune-related transcription factor binding sites were discovered in the putative 5'-flanking region. BLAST and phylogenetic analyses reveal that TmapoLp-III has high sequence identity (88%) with Tribolium castaneum apoLp-III but shares little sequence homologies (<26%) with other apoLp-IIIs. Homology modeling of Tm apoLp-III shows a bundle of five amphipathic alpha helices, including a short helix 3'. The 'helix-short helix-helix' motif was predicted to be implicated in lipid binding interactions, through reversible conformational changes and accommodating the hydrophobic residues to the exterior for stability. Highest level of TmapoLp-III mRNA was detected at late pupal stages, albeit it is expressed in the larval and adult stages at lower levels. The tissue specific expression of the transcripts showed significantly higher numbers in larval fat body and adult integument. In addition, TmapoLp-III mRNA was found to be highly upregulated in late stages of L. monocytogenes or E. coli challenge. These results indicate that TmapoLp-III may play an important role in innate immune responses against bacterial pathogens in T. molitor. Copyright © 2013 Elsevier B.V. All rights reserved.

Synthesis and in vivo evaluation of 201Tl(III)-DOTA complexes for applications in SPECT imaging.

PubMed

Hijnen, Nicole M; de Vries, Anke; Blange, Roy; Burdinski, Dirk; Grüll, Holger

2011-05-01

The aim of this study was to assess the use of (201)thallium(3+) ((201)Tl(3+)) as a radiolabel for nuclear imaging tracers. Methods for labeling of 1,4,7,10-tetraazacyclododecane-N,N',N″,N'″ tetraacetic acid (DOTA) and diethylenetriaminepentaacetic acid (DTPA) chelators with (201)Tl(3+) were investigated, and the levels of stability of these chelates were tested in vitro and in vivo. (201)Tl(I)Cl was treated with hydrochloric acid and ozone to form (201)Tl(III)Cl(3). The procedure for labeling of DOTA and DTPA was optimized, testing different buffer solutions and pH values. The stability levels of (201)Tl(III)-DOTA and (201)Tl(III)-DTPA were assessed in buffer, mouse serum and human serum (1:1, v/v) at a temperature of 310 K for 48 h. Subsequently, in vivo stability studies with (201)Tl(III)-DOTA were performed, comparing the biodistribution of (201)Tl(III)-DOTA with that of (201)Tl(I)Cl in a single-isotope study and with that of (177)Lu(III)-DOTA in a dual-isotope single photon emission computed tomography study. (201)Tl(III)-DTPA, (201)Tl(III)-DOTA and (177)Lu(III)-DOTA were prepared with >95% radiochemical purity. While (201)Tl(III)-DOTA showed a prolonged level of stability in buffer and serum, (201)Tl was quickly released from DTPA in serum. Apart from some urinary excretion, the biodistribution of DOTA-chelated (201)Tl(3+) was similar to that of free (ionic) (201)Tl(+) and did not match the biodistribution of (177)Lu(III)-DOTA. This indicated a limited stability of (201)Tl(III)-DOTA complexes in vivo. Despite promising results on the labeling and in vitro stability of (201)Tl(III)-DOTA, our in vivo results indicate that the integrity of (201)Tl(III)-DOTA decreases to <20% during the time required for urinary excretion, thereby limiting the use of (201)Tl(3+) as a radiolabel for tracer imaging. Copyright © 2011 Elsevier Inc. All rights reserved.

Canadian Contraception Consensus (Part 1 of 4).

PubMed

Black, Amanda; Guilbert, Edith; Costescu, Dustin; Dunn, Sheila; Fisher, William; Kives, Sari; Mirosh, Melissa; Norman, Wendy V; Pymar, Helen; Reid, Robert; Roy, Geneviève; Varto, Hannah; Waddington, Ashley; Wagner, Marie-Soleil; Whelan, Anne Marie; Ferguson, Carrie; Fortin, Claude; Kielly, Maria; Mansouri, Shireen; Todd, Nicole

2015-10-01

To provide guidelines for health care providers on the use of contraceptive methods to prevent pregnancy and on the promotion of healthy sexuality. Guidance for Canadian practitioners on overall effectiveness, mechanism of action, indications, contraindications, non-contraceptive benefits, side effects and risks, and initiation of cited contraceptive methods; family planning in the context of sexual health and general well-being; contraceptive counselling methods; and access to, and availability of, cited contraceptive methods in Canada. Published literature was retrieved through searches of Medline and The Cochrane Database from January 1994 to January 2015 using appropriate controlled vocabulary (e.g., contraception, sexuality, sexual health) and key words (e.g., contraception, family planning, hormonal contraception, emergency contraception). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English from January 1994 to January 2015. Searches were updated on a regular basis and incorporated in the guideline to June 2015. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. The quality of the evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table). Chapter 1: Contraception in Canada Summary Statements 1. Canadian women spend a significant portion of their lives at risk of an unintended pregnancy. (II-2) 2. Effective contraceptive methods are underutilized in Canada, particularly among vulnerable populations. (II-2) 3. Long-acting reversible contraceptive methods, including contraceptive implants and intrauterine contraception (copper-releasing and levonorgestrel-releasing devices/systems), are the most effective reversible contraceptive methods and have the highest continuation rates. (II-1) 4. Canada currently does not collect reliable data to determine the use of contraceptive methods, abortion rates, and the prevalence of unintended pregnancy among reproductive-age women. (II-2) 5. A universal subsidy for contraceptive methods as provided by many of Canada's peer nations and a few Canadian provinces may produce health system cost-savings. (II-2) 6. Health Canada approval processes for contraceptives have been less efficient than those of other drug approval agencies and Health Canada processes for other classes of pharmaceuticals. (II-2) 7. It is feasible and safe for contraceptives and family planning services to be provided by appropriately trained allied health professionals such as midwives, registered nurses, nurse practitioners, and pharmacists. (II-2) Recommendations 1. Contraceptive counselling should include a discussion of typical use failure rates and the importance of using the contraceptive method consistently and correctly in order to avoid pregnancy. (II-2A) 2. Women seeking contraception should be counselled on the wide range of effective methods of contraception available, including long-acting reversible contraceptive methods (LARCs). LARCs are the most effective methods of reversible contraception, have high continuation rates, and should be considered when presenting contraceptive options to any woman of reproductive age. (II-2A) 3. Family planning counselling should include counselling on the decline of fertility associated with increasing female age. (III-A) 4. Health policy supporting a universal contraception subsidy and strategies to promote the uptake of highly effective methods as cost-saving measures that improve health and health equity should be considered by Canadian health decision makers. (III-B) 5. Canadian health jurisdictions should consider expanding the scope of practice of other trained professionals such as nurses, nurse practitioners, midwives, and pharmacists and promoting task-sharing in family planning. (II-2B) 6. The Canadian Community Health Survey should include adequate reproductive health indicators in order for health care providers and policy makers to make appropriate decisions regarding reproductive health policies and services in Canada. (III-B) 7. Health Canada processes and policies should be reviewed to ensure a wide range of modern contraceptive methods are available to Canadian women. (III-B) Chapter 2: Contraceptive Care and Access Summary Statements 8. Although there are many contraceptive options in Canada, only a narrow range of contraceptive methods are commonly used by those of reproductive age. (II-3) 9. Condom use decreases with longer relationship tenure and when the sexual partner is considered to be the main partner, likely due to a lower perceived risk of sexually transmitted infection in that relationship. Condom use may also decrease markedly as an unintended consequence when an effective non-barrier method, such as hormonal contraception or intrauterine contraception, is initiated. (II-3) 10. Family planning counselling provides a natural segue into screening for concerns about sexual function or intimate partner violence. (III) 11. Well-informed and well-motivated individuals who have developed skills to practise safer sex behaviours are more likely to use contraceptive and safer sex methods effectively and consistently. (II-2) Recommendations 8. Comprehensive family planning services, including abortion services, should be accessible to all Canadians regardless of geographic location. These services should be confidential, non-judgemental, and respectful of individuals' privacy and cultural contexts. (III-A) 9. A contraceptive visit should include history taking, screening for contraindications, dispensing or prescribing a method of contraception, and exploring contraceptive choice and adherence in the broader context of the individual's sexual behaviour, reproductive health risk, social circumstances, and relevant belief systems. (III-B) 10. Health care providers should provide practical information on the wide range of contraceptive options and their potential non-contraceptive benefits and assist women and their partners in determining the best user-method fit. (III-B) 11. Health care providers should assist women and men in developing the skills necessary to negotiate the use of contraception and the correct and consistent use of a chosen method. (III-B) 12. Contraceptive care should include discussion and management of the risk of sexually transmitted infection, including appropriate recommendations for condom use and dual protection, STI screening, post-exposure prophylaxis, and Hepatitis B and human papillomavirus vaccination. (III-B) 13. Health care providers should emphasize the use of condoms not only for protection against sexually transmitted infection, but also as a back-up method when adherence to a hormonal contraceptive may be suboptimal. (I-A) 14. Health care providers should be aware of current media controversies in reproductive health and acquire relevant evidence-based information that can be briefly and directly communicated to their patients. (III-B) 15. Referral resources for intimate partner violence, sexually transmitted infections, sexual dysfunction, induced abortion services, and child protection services should be available to help clinicians provide contraceptive care in the broader context of women's health. (III-B) Chapter 3: Emergency Contraception Summary Statements 12. The copper intrauterine device is the most effective method of emergency contraception. (II-2) 13. A copper intrauterine device can be used for emergency contraception up to 7 days after unprotected intercourse provided that pregnancy has been ruled out and there are no other contraindications to its insertion. (II-2) 14. Levonorgestrel emergency contraception is effective up to 5 days (120 hours) after intercourse; its effectiveness decreases as the time between unprotected intercourse and ingestion increases. (II-2) 15. Ulipristal acetate for emergency contraception is more effective than levonorgestrel emergency contraception up to 5 days after unprotected intercourse. This difference in effectiveness is more pronounced as the time from unprotected intercourse increases, especially after 72 hours. (I) 16. Hormonal emergency contraception (levonorgestrel emergency contraception and ulipristal acetate for emergency contraception) is not effective if taken on the day of ovulation or after ovulation. (II-2) 17. Levonorgestrel emergency contraception may be less effective in women with a body mass index > 25 kg/m2 and ulipristal acetate for emergency contraception may be less effective in women with a body mass index > 35 kg/m2. However, hormonal emergency contraception may still retain some effectiveness regardless of a woman's body weight or body mass index. (II-2) 18. Hormonal emergency contraception is associated with higher failure rates when women continue to have subsequent unprotected intercourse. (II-2) 19. Hormonal contraception can be initiated the day of or the day following the use of levonorgestrel emergency contraception, with back-up contraception used for the first 7 days. (III) 20. Hormonal contraception can be initiated 5 days following the use of ulipristal acetate for emergency contraception, with back-up contraception used for the first 14 days. (III) Recommendations 16. All emergency contraception should be initiated as soon as possible after unprotected intercourse. (II-2A) 17. Women should be informed that the copper intrauterine device (IUD) is the most effective method of emergency contraception and can be used by any woman with no contraindications to IUD use. (II-3A) 18.

Dependence of mobility on the electron concentration upon scattering at polar optical phonons in A{sup III}–N nitrides

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

Borisenko, S. I., E-mail: sib@tpu.ru

2016-04-15

The dependence of the effective relaxation time on the electron concentration in A{sup III}–N nitrides in the case of electron scattering at polar longitudinal optical phonons is calculated by the marching method. The method takes into account the inelasticity of electron scattering at polar optical phonons for nitrides in the zinc-blende approximation. The calculations show a substantial increase in mobility in samples with a degenerate electron gas, if screening of the long-range potential of polar longitudinal optical phonons is taken into account.

Differential cDNA cloning by enzymatic degrading subtraction (EDS).

PubMed Central

Zeng, J; Gorski, R A; Hamer, D

1994-01-01

We describe a new method, called enzymatic degrading subtraction (EDS), for the construction of subtractive libraries from PCR amplified cDNA. The novel features of this method are that i) the tester DNA is blocked by thionucleotide incorporation; ii) the rate of hybridization is accelerated by phenol-emulsion reassociation; and iii) the driver cDNA and hybrid molecules are enzymatically removed by digestion with exonucleases III and VII rather than by physical partitioning. We demonstrate the utility of EDS by constructing a subtractive library enriched for cDNAs expressed in adult but not in embryonic rat brains. Images PMID:7971268

Analysis of gold(I/III)-complexes by HPLC-ICP-MS demonstrates gold(III) stability in surface waters.

PubMed

Ta, Christine; Reith, Frank; Brugger, Joël; Pring, Allan; Lenehan, Claire E

2014-05-20

Understanding the form in which gold is transported in surface- and groundwaters underpins our understanding of gold dispersion and (bio)geochemical cycling. Yet, to date, there are no direct techniques capable of identifying the oxidation state and complexation of gold in natural waters. We present a reversed phase ion-pairing HPLC-ICP-MS method for the separation and determination of aqueous gold(III)-chloro-hydroxyl, gold(III)-bromo-hydroxyl, gold(I)-thiosulfate, and gold(I)-cyanide complexes. Detection limits for the gold species range from 0.05 to 0.30 μg L(-1). The [Au(CN)2](-) gold cyanide complex was detected in five of six waters from tailings and adjacent monitoring bores of working gold mines. Contrary to thermodynamic predictions, evidence was obtained for the existence of Au(III)-complexes in circumneutral, hypersaline waters of a natural lake overlying a gold deposit in Western Australia. This first direct evidence for the existence and stability of Au(III)-complexes in natural surface waters suggests that Au(III)-complexes may be important for the transport and biogeochemical cycling of gold in surface environments. Overall, these results show that near-μg L(-1) enrichments of Au in environmental waters result from metastable ligands (e.g., CN(-)) as well as kinetically controlled redox processes leading to the stability of highly soluble Au(III)-complexes.

Phylogenetic analysis of the envelope protein (domain lll) of dengue 4 viruses

PubMed Central

Mota, Javier; Ramos-Castañeda, José; Rico-Hesse, Rebeca; Ramos, Celso

2011-01-01

Objective To evaluate the genetic variability of domain III of envelope (E) protein and to estimate phylogenetic relationships of dengue 4 (Den-4) viruses isolated in Mexico and from other endemic areas of the world. Material and Methods A phylogenetic study of domain III of envelope (E) protein of Den-4 viruses was conducted in 1998 using virus strains from Mexico and other parts of the world, isolated in different years. Specific primers were used to amplify by RT-PCR the domain III and to obtain nucleotide sequence. Based on nucleotide and deduced aminoacid sequence, genetic variability was estimated and a phylogenetic tree was generated. To make an easy genetic analysis of domain III region, a Restriction Fragment Length Polymorphism (RFLP) assay was performed, using six restriction enzymes. Results Study results demonstrate that nucleotide and aminoacid sequence analysis of domain III are similar to those reported from the complete E protein gene. Based on the RFLP analysis of domain III using the restriction enzymes Nla III, Dde I and Cfo I, Den-4 viruses included in this study were clustered into genotypes 1 and 2 previously reported. Conclusions Study results suggest that domain III may be used as a genetic marker for phylogenetic and molecular epidemiology studies of dengue viruses. The English version of this paper is available too at: http://www.insp.mx/salud/index.html PMID:12132320

Method of preparing nitrogen containing semiconductor material

DOEpatents

Barber, Greg D.; Kurtz, Sarah R.

2004-09-07

A method of combining group III elements with group V elements that incorporates at least nitrogen from a nitrogen halide for use in semiconductors and in particular semiconductors in photovoltaic cells.

40 CFR Appendix D to Part 300 - Appropriate Actions and Methods of Remedying Releases

Code of Federal Regulations, 2011 CFR

2011-07-01

... facultative lagoons. (C) Supported growth biological reactors. (D) Microbial biodegradation. (ii) Chemical...) Neutralization. (D) Equalization. (E) Chemical oxidation. (iii) Physical methods, including the following: (A...

Osthole inhibits the expressions of collagen I and III through Smad signaling pathway after treatment with TGF-β1 in mouse cardiac fibroblasts.

PubMed

Liu, Jin-Cheng; Wang, Feng; Xie, Mei-Lin; Cheng, Zong-Qi; Qin, Qiong; Chen, Lin; Chen, Rong

2017-02-01

Osthole, a natural coumarin and bioactive compound isolated from the fruit of Cnidium monnieri (L.) Cusson, was reported to prevent isoprenaline-induced myocardial fibrosis in mice by inhibiting the transforming growth factor-β1 (TGF-β1) expression, but the underlying mechanism is still unclear. The aim of this study is to illuminate whether the mechanism of osthole inhibiting collagen I and III expressions is associated with Smad signaling pathway in mouse cardiac fibroblasts (CFs) treated with TGF-β1. The mouse CFs stimulated with TGF-β1 were cultured and treated with osthole 1.25-5μg/ml for 24h. The expressions of α-SMA, collagen I, collagen III, TGF-β receptor I (TβRI), Smad2/3, phospho-Smad2/3 (P-Smad2/3), Smad4 and Smad7 were detected by real-time PCR method and western blot method, respectively. After treatment with TGF-β1 and osthole in CFs, the levels of α-SMA expression and collagen I and III were reduced by osthole treatment. Accordingly, the ratio of collagen I/III had a similar changing trend. Besides, the levels of TβRI, Smad2/3, P-Smad2/3 and Smad4 expressions were decreased, while the level of Smad7 expression was increased after treatment with osthole. The present results demonstrated that osthole could inhibit the collagen I and III expressions and their ratio in CFs treated with TGF-β1 via Smad signaling pathway, which might be one of its anti-fibrotic action mechanisms. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Dust extinction in the first galaxies

NASA Astrophysics Data System (ADS)

Jaacks, Jason; Finkelstein, Steven L.; Bromm, Volker

2018-04-01

Using cosmological volume simulations and a custom built sub-grid model for Population III (Pop III) star formation, we examine the baseline dust extinction in the first galaxies due to Pop III metal enrichment in the first billion years of cosmic history. We find that although the most enriched, high-density lines of sight in primordial galaxies can experience a measurable amount of extinction from Pop III dust [E(B - V)max = 0.07, AV, max ≈ 0.28], the average extinction is very low with ≲ 10-3. We derive a power-law relationship between dark matter halo mass and extinction of E(B-V)∝ M_halo^{0.80}. Performing a Monte Carlo parameter study, we establish the baseline reddening of the ultraviolet spectra of dwarf galaxies at high redshift due to Pop III enrichment only. With this method, we find <βUV> - 2.51 ± 0.07, which is both nearly halo mass and redshift independent.

Modelling the arsenic (V) and (III) adsorption

NASA Astrophysics Data System (ADS)

Rau, I.; Meghea, A.; Peleanu, I.; Gonzalo, A.; Valiente, M.; Zaharescu, M.

2003-01-01

Arsenic has gained great notoriety historically for its toxic properties. In aquatic environment, arsenic can exist in several oxidation states, as both inorganic and organometallic species. As (V) is less toxic than As (III). Most research has been directed to the control of arsenic pollution of potable water. Various techniques such as precipitation with iron and aluminium hydroxides, ion exchange, reverse osmosis, and adsorption are used for As (V) removal from surface and waste waters. Because of the easy handling of sludge, its free operation and regeneration capability, the adsorption technique has secured a place as one of the advanced methods of arsenic removal. A study of As (III) and As (V) sorption onto some different adsorbents (Fe (III) — iminodiacetate resin, nanocomposite materials, Fe(III) — forager sponge) referring to kinetic considerations and modelling of the process will be presented. All the systems studied are better described by Freundlich-Langmuir isotherm and the rate constant evaluation shows a sub-unitary order for the adsorption process.

Oxidation of As(III) to As(V) using ozone microbubbles.

PubMed

Khuntia, Snigdha; Majumder, Subrata Kumar; Ghosh, Pallab

2014-02-01

The use of ozone in the treatment of water and wastewater is rapidly increasing due to its high oxidizing power. Arsenic is one the most toxic elements found in water. As(III) and As(V) are the major sources of arsenic poisoning. It is known that As(V) can be more easily removed from water by adsorptive methods than As(III). In this work, oxidation of more toxic As(III) to less toxic As(V) was studied in a pilot-plant by using ozone microbubbles. The microbubbles were effective in dissolving ozone in water. The oxidation was fast over a wide range of pH (e.g., 4-9). The role of hydroxyl radical in the oxidation of As(III) under acidic conditions was investigated by using 2-propanol as the hydroxyl radical scavenger. Under acidic conditions, the addition of 2-propanol slowed down the oxidation, which proves that hydroxyl radicals were involved in the oxidation process. The effect of carbonate ions on the rate of oxidation was investigated. It was found that the generation of carbonate ion radical from the carbonate ion accelerated the oxidation of As(III). The kinetics of oxidation of As(III) by ozone was studied. Copyright © 2013 Elsevier Ltd. All rights reserved.

Rapid identification of Enterobacter hormaechei and Enterobacter cloacae genetic cluster III.

PubMed

Ohad, S; Block, C; Kravitz, V; Farber, A; Pilo, S; Breuer, R; Rorman, E

2014-05-01

Enterobacter cloacae complex bacteria are of both clinical and environmental importance. Phenotypic methods are unable to distinguish between some of the species in this complex, which often renders their identification incomplete. The goal of this study was to develop molecular assays to identify Enterobacter hormaechei and Ent. cloacae genetic cluster III which are relatively frequently encountered in clinical material. The molecular assays developed in this study are qPCR technology based and served to identify both Ent. hormaechei and Ent. cloacae genetic cluster III. qPCR results were compared to hsp60 sequence analysis. Most clinical isolates were assigned to Ent. hormaechei subsp. steigerwaltii and Ent. cloacae genetic cluster III. The latter was proportionately more frequently isolated from bloodstream infections than from other material (P < 0·05). The qPCR assays detecting Ent. hormaechei and Ent. cloacae genetic cluster III demonstrated high sensitivity and specificity. The presented qPCR assays allow accurate and rapid identification of clinical isolates of the Ent. cloacae complex. The improved identifications obtained can specifically assist analysis of Ent. hormaechei and Ent. cloacae genetic cluster III in nosocomial outbreaks and can promote rapid environmental monitoring. An association was observed between Ent. cloacae cluster III and systemic infection that deserves further attention. © 2014 The Society for Applied Microbiology.

Characterization and Thermodynamic Relationship of Three Polymorphs of a Xanthine Oxidase Inhibitor, Febuxostat.

PubMed

Patel, Jinish; Jagia, Moksh; Bansal, Arvind Kumar; Patel, Sarsvatkumar

2015-11-01

Febuxostat (FXT), a xanthine oxidase inhibitor, is an interesting and unique molecule, which exhibits extensive polymorphism, with over 15 polymorphic forms reported to date. The primary purpose of the study was to characterize the three polymorphic forms with respect to their thermodynamic quantities and establish thermodynamic relationship between them. The polymorphs were characterized by thermal and powder X-ray diffraction methods. Three different methods were used to calculate the transition temperatures (Ttr) and thereby their thermodynamic relationships. Although the first and second method used calorimetric data (melting point and heat of fusion), the third method employed the use of configurational free energy phase diagram. The onset melting points of three polymorphic forms were found to be 482.89 ± 0.37 K for form I, 476.30 ± 1.21 K for form II, and 474.19 ± 0.11 K for form III. Moreover, the powder X-ray diffraction patterns for each form were also unique. The polymorphic pair of form I and II and of form I and III was found to be enantiotropic, whereas pair of form II and III was monotropic. Besides the relative thermodynamic aspects (free energy differences, enthalpy, entropy contributions) using different methods, the pharmaceutical implications and phase transformation aspects have also been covered. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Method of analyzing multiple sample simultaneously by detecting absorption and systems for use in such a method

DOEpatents

Yeung, Edward S.; Gong, Xiaoyi

2004-09-07

The present invention provides a method of analyzing multiple samples simultaneously by absorption detection. The method comprises: (i) providing a planar array of multiple containers, each of which contains a sample comprising at least one absorbing species, (ii) irradiating the planar array of multiple containers with a light source and (iii) detecting absorption of light with a detetion means that is in line with the light source at a distance of at leaat about 10 times a cross-sectional distance of a container in the planar array of multiple containers. The absorption of light by a sample indicates the presence of an absorbing species in it. The method can further comprise: (iv) measuring the amount of absorption of light detected in (iii) indicating the amount of the absorbing species in the sample. Also provided by the present invention is a system for use in the abov metho.The system comprises; (i) a light source comrnpising or consisting essentially of at leaat one wavelength of light, the absorption of which is to be detected, (ii) a planar array of multiple containers, and (iii) a detection means that is in line with the light source and is positioned in line with and parallel to the planar array of multiple contiainers at a distance of at least about 10 times a cross-sectional distance of a container.

Determination of total antioxidant capacity by a new spectrofluorometric method based on Ce(IV) reduction: Ce(III) fluorescence probe for CERAC assay.

PubMed

Ozyurt, Dilek; Demirata, Birsen; Apak, Resat

2011-11-01

A Ce(IV)-based reducing capacity (CERAC) assay was developed to measure the total antioxidant capacity (TAC) of foods, in which Ce(IV) would selectively oxidize antioxidant compounds but not citric acid and reducing sugars which are not classified as antioxidants. The method is based on the electron-transfer (ET) reaction between Ce(IV) ion and antioxidants in optimized acidic sulphate medium (i.e., 0.3 M H(2)SO(4) and 0.7 M Na(2)SO(4)) and subsequent determination of the produced Ce(III) ions by a fluorometric method. The fluorescent product, Ce(III), exhibited strong fluorescence at 360 nm with an excitation wavelength of 256 nm, the fluorescence intensity being correlated to antioxidant power of the original sample. The linear concentration range for most antioxidants was quite wide, e.g., 5.0 × 10(-7)-1.0 × 10(-5) M for quercetin. The developed procedure was successfully applied to the TAC assay of antioxidant compounds such as trolox, quercetin, gallic acid, ascorbic acid, catechin, naringin, naringenin, caffeic acid, ferulic acid, glutathione, and cysteine. The proposed method was reproducible, additive in terms of TAC values of constituents of complex mixtures, and the trolox equivalent antioxidant capacities (TEAC coefficients) of the tested antioxidant compounds gave good correlations with those found by reference methods such as ABTS and CUPRAC.

Simultaneous Speciation of Arsenic, Selenium, and Chromium by HPLC-ICP-MS

USGS Publications Warehouse

Wolf, Ruth E.; Morman, Suzette A.; Morrison, Jean M.; Lamothe, Paul J.

2008-01-01

An adaptation of an analytical method developed for chromium speciation has been utilized for the simultaneous determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) species using high performance liquid chromatography (HPLC) separation with ICP-MS detection. Reduction of interferences for the determination of As, Se, and Cr by ICP-MS is a major consideration for this method. Toward this end, a Dynamic Reaction Cell (DRC) ICP-MS system was used to detect the species eluted from the chromatographic column. A variety of reaction cell gases and conditions may be utilized, and the advantages and limitations of the gases tested to date will be presented and discussed. The separation and detection of the As, Se, and Cr species of interest can be achieved using the same chromatographic conditions in less than 2 minutes by complexing the Cr(III) with EDTA prior to injection on the HPLC column. Practical aspects of simultaneous speciation analysis will be presented and discussed, including issues with HPLC sample vial contamination, standard and sample contamination, species stability, and considerations regarding sample collection and preservation methods. The results of testing to determine the method's robustness to common concomitant element and anion effects will also be discussed. Finally, results will be presented using the method for the analysis of a variety of environmental and geological samples including waters, soil leachates and simulated bio-fluid leachates.

26 CFR 1.446-1 - General rule for methods of accounting.

Code of Federal Regulations, 2011 CFR

2011-04-01

... books. For requirement respecting the adoption or change of accounting method, see section 446(e) and... taxpayer to adopt or change to a method of accounting permitted by this chapter although the method is not..., which require the prior approval of the Commissioner in the case of changes in accounting method. (iii...

Differential electrolytic potentiometric titration method for the determination of ciprofloxacin in drug formulations.

PubMed

Abulkibash, Abdalla M; Sultan, Salah M; Al-Olyan, Abeer M; Al-Ghannam, Sheikha M

2003-10-17

A simple and rapid differential electrolytic potentiometric titration method for the determination of ciprofloxacin was developed. The work is based on the fast complexation reaction between iron(III) and ciprofloxacin in a ratio of 1:3, respectively, in sulfuric acid media of 0.09 mol dm(-3). Among the electrodes tested silver amalgam electrodes were found to be a suitable indicating system. By applying a current density of 0.5 muA cm(-2) to these electrodes and using iron(III) solution of 0.097 mol dm(-3) as a titrant, normal titration curves were obtained. The method was successfully applied for the determination of ciprofloxacin in drug formulations as low as 4.0 ppm.

7 CFR 3015.102 - Payment methods.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 15 2014-01-01 2014-01-01 false Payment methods. 3015.102 Section 3015.102... methods. (a) Non-construction. (1) Letters of credit will be used to pay USDA recipients when all the... (iii) of this section. (3) Reimbursement by Treasury check shall be the preferred method when the...

7 CFR 3015.102 - Payment methods.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 15 2012-01-01 2012-01-01 false Payment methods. 3015.102 Section 3015.102... methods. (a) Non-construction. (1) Letters of credit will be used to pay USDA recipients when all the... (iii) of this section. (3) Reimbursement by Treasury check shall be the preferred method when the...

7 CFR 3015.102 - Payment methods.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 15 2013-01-01 2013-01-01 false Payment methods. 3015.102 Section 3015.102... methods. (a) Non-construction. (1) Letters of credit will be used to pay USDA recipients when all the... (iii) of this section. (3) Reimbursement by Treasury check shall be the preferred method when the...

7 CFR 3015.102 - Payment methods.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 15 2010-01-01 2010-01-01 false Payment methods. 3015.102 Section 3015.102... methods. (a) Non-construction. (1) Letters of credit will be used to pay USDA recipients when all the... (iii) of this section. (3) Reimbursement by Treasury check shall be the preferred method when the...

7 CFR 3015.102 - Payment methods.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 15 2011-01-01 2011-01-01 false Payment methods. 3015.102 Section 3015.102... methods. (a) Non-construction. (1) Letters of credit will be used to pay USDA recipients when all the... (iii) of this section. (3) Reimbursement by Treasury check shall be the preferred method when the...

Synthesis, characterization and physicochemical studies of new chelating resin 1, 8-(3, 6-dithiaoctyl)-4-polyvinylbenzenesulphonate (dpvbs) and its metallopolymer Cu(II), Ni(II), Co(II) and Fe(III) complexes

NASA Astrophysics Data System (ADS)

Khalil, Tarek E.; Elbadawy, Hemmat A.; El-Dissouky, Ali

2018-02-01

A new chelating resin, 1,8-(3,6-dithiaoctyl)-4-polyvinylbenzenesulphonate (dpvbs) has been synthesized by coupling Amberlite XAD-16 with (2,2‧-ethylenedithio) diethanol using pyridine/CH2Cl2 mixture as a solvent. The chelating resin and its metallopolymer Cu(II), Ni(II), Co(II) and Fe(III) complexes have been synthesized and characterized by EDS, SEM, XPS, elemental analysis, spectral (IR, UV/Vis, EPR). The thermal analysis of the resin and its metallopolymer complexes indicated an endothermic spontaneous sorption mechanism with the liberation of water of hydration of the metal ions and that adsorbed by the free resin. At the solid liquid interface, the degrees of freedom increased during the sorption of the metal ions onto the resin. The surface area of polymer support and its metallopolymer complexes are estimated by (BJH) method. The batch equilibrium method was used for studying the metal sorption and selectivity at different pH values and different contact times at room temperature. ICP-AES was used to estimate the metal capacity of the resin for sorption of Cu(II), Ni(II), Co(II) and Fe(III) from aqueous solutions utilizing the batch equilibrium method. The sorption tendency of the metal ions by the resin was found to be: Cu(II) > Fe(III) > Co(II) > Ni(II). Adsorption kinetics was found to be fit the pseudo-second order model.

Simultaneous determination and pharmacokinetic study of Atractylenolide I, II and III in rat plasma after intragastric administration of Baizhufuling extract and Atractylodis extract by UPLC-MS/MS.

PubMed

Yan, Han; Sun, Yuanyuan; Zhang, Qili; Yang, Mingjing; Wang, Xiaorui; Wang, Yang; Yu, Zhiguo; Zhao, Yunli

2015-07-01

A simple and rapid ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the simultaneous determination of Atractylenolide I, II and III in rat plasma. Plasma samples were processed by liquid-liquid extraction with ethyl acetate, using schisandrin as internal standard (IS). Chromatographic separation was accomplished on a Thermo Hypersil GOLD C18 column (2.1mm×50mm, 1.9μm) with mobile phase consisting of acetonitrile and 0.1% formic acid-water (50:50, v/v). The detection was carried out by ESI-MS (positive ionization mode) and low-energy collision dissociation tandem mass spectrometric analyses using the multiple-reaction monitoring (MRM) scan mode. The quantification was performed using the transitions of the protonated molecule→product ion at m/z 231.0→185.1 for Atractylenolide I, at m/z 233.1→187.1 for Atractylenolide II and at m/z 249.1→231.1 for Atractylenolide III, respectively. Method validation revealed excellent linearity over investigated range together with satisfactory intra- and inter-day precision, accuracy, matrix effects and extraction recoveries. This method was successfully applied to the comparative pharmacokinetic study of Atractylenolide I, II and III in rat plasma after intragastric administration of Baizhufuling extract and Atractylodis extract. Copyright © 2015 Elsevier B.V. All rights reserved.

Design of Phase II Non-inferiority Trials.

PubMed

Jung, Sin-Ho

2017-09-01

With the development of inexpensive treatment regimens and less invasive surgical procedures, we are confronted with non-inferiority study objectives. A non-inferiority phase III trial requires a roughly four times larger sample size than that of a similar standard superiority trial. Because of the large required sample size, we often face feasibility issues to open a non-inferiority trial. Furthermore, due to lack of phase II non-inferiority trial design methods, we do not have an opportunity to investigate the efficacy of the experimental therapy through a phase II trial. As a result, we often fail to open a non-inferiority phase III trial and a large number of non-inferiority clinical questions still remain unanswered. In this paper, we want to develop some designs for non-inferiority randomized phase II trials with feasible sample sizes. At first, we review a design method for non-inferiority phase III trials. Subsequently, we propose three different designs for non-inferiority phase II trials that can be used under different settings. Each method is demonstrated with examples. Each of the proposed design methods is shown to require a reasonable sample size for non-inferiority phase II trials. The three different non-inferiority phase II trial designs are used under different settings, but require similar sample sizes that are typical for phase II trials.

Improved synthesis of carbon-clad silica stationary phases.

PubMed

Haidar Ahmad, Imad A; Carr, Peter W

2013-12-17

Previously, we described a novel method for cladding elemental carbon onto the surface of catalytically activated silica by a chemical vapor deposition (CVD) method using hexane as the carbon source and its use as a substitute for carbon-clad zirconia.1,2 In that method, we showed that very close to exactly one uniform monolayer of Al (III) was deposited on the silica by a process analogous to precipitation from homogeneous solution in order to preclude pore blockage. The purpose of the Al(III) monolayer is to activate the surface for subsequent CVD of carbon. In this work, we present an improved procedure for preparing the carbon-clad silica (denoted CCSi) phases along with a new column packing process. The new method yields CCSi phases having better efficiency, peak symmetry, and higher retentivity compared to carbon-clad zirconia. The enhancements were achieved by modifying the original procedure in three ways: First, the kinetics of the deposition of Al(III) were more stringently controlled. Second, the CVD chamber was flushed with a mixture of hydrogen and nitrogen gas during the carbon cladding process to minimize generation of polar sites by oxygen incorporation. Third, the fine particles generated during the CVD process were exhaustively removed by flotation in an appropriate solvent.

The Impact of Theoretical Orientation and Training on Preference for Diagnostic Models of Personality Pathology.

PubMed

Paggeot, Amy; Nelson, Sharon; Huprich, Steven

2017-01-01

The role of theoretical orientation in determining preference for different methods of diagnosis has been largely unexplored. The goal of the present study was to explore ratings of the usefulness of 4 diagnostic methods after applying them to a patient: prototype ratings derived from the SWAP-II, the DSM-5 Section III specific personality disorders, the DSM-5 Section III trait model, and prototype ratings derived from the Psychodynamic Diagnostic Manual (PDM). Three hundred and twenty-nine trainees in APA-accredited doctoral programs and internships rated one of their current patients with each of the 4 diagnostic methods. Individuals who classified their theoretical orientation as "cognitive- behavioral" displayed a significantly greater preference for the proposed DSM-5 personality disorder prototypes when compared to individuals who classified their orientation as "psychodynamic/psychoanalytic," while individuals who considered themselves psychodynamic or psychoanalytic rated the PDM as significantly more useful than those who considered themselves cognitive-behavioral. Individuals who classified their graduate program as a PsyD program were also more likely to rate the DSM-5 Section III and PDM models as more useful diagnostic methods than individuals who classified their graduate program as a PhD program. Implications and future directions will be discussed. © 2017 S. Karger AG, Basel.

Methods for improved growth of group III nitride semiconductor compounds

DOEpatents

Melnik, Yuriy; Chen, Lu; Kojiri, Hidehiro

2015-03-17

Methods are disclosed for growing group III-nitride semiconductor compounds with advanced buffer layer technique. In an embodiment, a method includes providing a suitable substrate in a processing chamber of a hydride vapor phase epitaxy processing system. The method includes forming an AlN buffer layer by flowing an ammonia gas into a growth zone of the processing chamber, flowing an aluminum halide containing precursor to the growth zone and at the same time flowing additional hydrogen halide or halogen gas into the growth zone of the processing chamber. The additional hydrogen halide or halogen gas that is flowed into the growth zone during buffer layer deposition suppresses homogeneous AlN particle formation. The hydrogen halide or halogen gas may continue flowing for a time period while the flow of the aluminum halide containing precursor is turned off.

Method for the Study of Category III Airborne Procedure Reliability

DOT National Transportation Integrated Search

1973-03-01

A method for the study of Category 3 airborne-procedure reliability is presented. The method, based on PERT concepts, is considered to have utility at the outset of a procedure-design cycle and during the early accumulation of actual performance data...

Report of Communication Method Usage by Teachers of Deaf-Blind Children--Part III.

ERIC Educational Resources Information Center

Jensema, Corinne Klein

1981-01-01

Conclusions from a national survey of communication methods used by 195 deaf-blind students included that children with moderate and moderate-severe vision losses prefer visually presented gestures and IQ had little effect on choice of methods. (Author)

Mentha-Stabilized Silver Nanoparticles for High-Performance Colorimetric Detection of Al(III) in Aqueous Systems.

PubMed

Sharma, Rekha; Dhillon, Ankita; Kumar, Dinesh

2018-03-26

The present paper reports a facile and selective colorimetric method for the detection of potential environmental and health hazardous metal ions using green synthesized silver nanoparticles (AgNPs). Here the organic functional groups present in the plant extract (Mentha arvensis) are used as reductants and stabilizers in the synthesis of AgNPs. They also provide a suitable binding site to the (Al(III)) analyte in the detection mechanism. The leaf extract of Mentha arvensis was used to synthesize AgNPs at room-temperature and at 80 °C. The AgNPs synthesized at 80 °C exhibit excellent selective colorimetric detection of Al(III). The as-synthesized AgNPs have been characterized, and the synthesis, stabilization of NPs and detection mechanism has also been illustrated by using UV-vis, XPS, FTIR, TEM, EDX, SEM, AAS, and TGA analytical tools and techniques. The selectivity of detection probe was supported by the reaction between probe and metal ions followed first-order kinetics having the highest value of the regression coefficient (R 2  = 0.99) for Al(III) and the analysis of thermodynamic parameters. The prepared sensor showed a lower limit of detection (LOD) of 1 nM (S/N = 3.2) in real water samples. The proposed method can be successfully utilized for the detection of Al(III) from both drinking and real water samples at the nanomolar level.

Effect of a novel sterilization method on biomechanical properties of soft tissue allografts.

PubMed

Baldini, T; Caperton, K; Hawkins, M; McCarty, E

2016-12-01

Evaluate allograft tissue commonly used in soft tissue reconstruction to determine whether stiffness and strength were significantly altered after grafts were treated with different sterilization methods. Unprocessed, irradiated, and grafts treated with supercritical CO 2 were compared. Thirty-eight anterior or posterior tibialis tendons were obtained from a tissue bank (Allograft Innovations, Gainesville, FL). Group I was unprocessed, group II was sterilized with gamma irradiation (20-28 kGy), and group III was sterilized with supercritical CO 2 . The grafts were pretensioned to 89 N for 300 s. Specimens were then loaded from 50 to 300 N at 0.5 Hz for 250 cycles before being loaded to failure at 50 mm/min. Dependent variables were compared between sterilization groups with one-way ANOVA (P < 0.05) and equivalence trial. There was no significant difference in load to failure or failure stress among groups I, II, and III. Group III resulted in 27-36 % lower stiffness than group I and II. This difference was significant at 1, 10, 50, 100, and 250 cycles. There was no significant difference in stiffness between group I and group II. The two sterilization methods tested in this study do not affect allograft strength. The supercritical CO 2 sterilization method resulted in significantly lower stiffness than unprocessed and irradiated allografts. However, the stiffness and strength of all groups tested were greater than that of published values of the native intact anterior cruciate ligament (ACL). This study provides previously unpublished mechanical test data on a new sterilization technique that will assist surgeons to decide which allograft to use in ACL reconstruction surgery. III.

Simultaneous quantification of flavonoids in blood plasma by a high-performance liquid chromatography method after oral administration of Blumea balsamifera leaf extracts in rats.

PubMed

Nessa, Fazilatun; Ismail, Zhari; Mohamed, Nornisah; Karupiah, Sundram

2013-03-01

The leaves of Blumea balsamifera are used as a folk medicine in kidney stone diseases in South-East Asia. Phytochemical investigation revealed leaves contained a number of flavonoids. In view of these, the present work was aimed to quantify and preliminary pharmacokinetic investigation of five flavonoids viz. dihydroquercetin-7,4¢-dimethyl ether (I), dihydroquercetin-4¢-methyl ether (II), 5,7,3¢,5¢-tetrahydroxyflavanone (III), blumeatin (IV) and quercetin (V) in rat plasma following oral administration (0.5g/Kg) of B. balsamifera leaf extract in rats. Quantification was achieved by using a validated, reproducible high-performance liquid chromatographic method. The mean recoveries of I, II, III, IV and V were 90.6, 93.4, 93.5, 91.2 and 90.3% respectively. The limit of quantification was 25 ng/mL for I and IV, 10 ng/mL for II and III and 100 ng/mL for V respectively. The within day and day-to-day precision for all the compounds were < 10%. The validated HPLC method herein was applied for pharmacokinetic studies and the main pharmacokinetic parameters were: t1/2 (hr) 5.8, 4.3, 2.9, 5.7 and 7.3, Cmax (ng/mL) 594.9, 1542.9 1659.9, 208.9 and 3040.4; Tmax (hr) 4.7, 1.0, 1.0, 3.5 and 2.3; AUC0-oo (ng hr/mL) 5040, 5893, 9260, 1064 and 27233 for I, II, III, IV and V respectively. The developed method was suitable for pharmacokinetic studies and this preliminary study also revealed significant absorption after oral dosing in rats.

Tracking emerging mycotoxins in food: development of an LC-MS/MS method for free and modified Alternaria toxins.

PubMed

Puntscher, Hannes; Kütt, Mary-Liis; Skrinjar, Philipp; Mikula, Hannes; Podlech, Joachim; Fröhlich, Johannes; Marko, Doris; Warth, Benedikt

2018-05-16

Mycotoxins produced by Alternaria fungi are ubiquitous food contaminants, but analytical methods for generating comprehensive exposure data are rare. We describe the development of an LC-MS/MS method covering 17 toxins for investigating the natural occurrence of free and modified Alternaria toxins in tomato sauce, sunflower seed oil, and wheat flour. Target analytes included alternariol (AOH), AOH-3-glucoside, AOH-9-glucoside, AOH-3-sulfate, alternariol monomethyl ether (AME), AME-3-glucoside, AME-3-sulfate, altenuene, isoaltenuene, tenuazonic acid (TeA), tentoxin (TEN), altertoxin I and II, alterperylenol, stemphyltoxin III, altenusin, and altenuic acid III. Extensive optimization resulted in a time- and cost-effective sample preparation protocol and a chromatographic baseline separation of included isomers. Overall, adequate limits of detection (0.03-9 ng/g) and quantitation (0.6-18 ng/g), intermediate precision (9-44%), and relative recovery values (75-100%) were achieved. However, stemphyltoxin III, AOH-3-sulfate, AME-3-sulfate, altenusin, and altenuic acid III showed recoveries in wheat flour below 70%, while their performance was stable and reproducible. Our pilot study with samples from the Austrian retail market demonstrated that tomato sauces (n = 12) contained AOH, AME, TeA, and TEN in concentrations up to 20, 4, 322, and 0.6 ng/g, while sunflower seed oil (n = 7) and wheat flour samples (n = 9) were contaminated at comparatively lower levels. Interestingly and of relevance for risk assessment, AOH-9-glucoside, discovered for the first time in naturally contaminated food items, and AME-3-sulfate were found in concentrations similar to their parent toxins. In conclusion, the established multi-analyte method proved to be fit for purpose for generating comprehensive Alternaria toxin occurrence data in different food matrices. Graphical abstract ᅟ.

Dispersive micro-solid phase extraction combined with dispersive liquid-liquid microextraction for speciation analysis of antimony by electrothermal vaporization inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Chen, Shizhong; Zhu, Shengping; Lu, Dengbo

2018-01-01

A method was developed for speciation analysis of antimony by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) after preconcentration/separation using dispersive micro-solid phase extraction (DMSPE) and dispersive liquid-liquid micro-extraction (DLLME). In DMSPE, titanium dioxide nanofibers were used for preconcentration and separation of analytes. The upper aqueous phase and elution solution from DMSPE were used for further preconcentration and separation of Sb(III) and Sb(V) by DLLME without any pre-oxidation or pre-reduction operation, respectively. The extracts from DLLME were used for ETV-ICP-MS determination with APDC as a chemical modifier. Under optimal conditions, the detection limits of this method were 0.019 and 0.025 pg mL- 1 with relative standard deviations of 5.7% and 6.9% for Sb(III) and Sb(V) (c = 1.0 ng mL- 1, n = 9), respectively. This method was applied for speciation analysis of Sb and its distribution in the tea leaves and the tea infusion, including total, suspended, soluble, organic and inorganic Sb as well as Sb(III) and Sb(V). The results showed that the contents of Sb are 62.7, 12.9 and 47.3 ng g- 1 in the tea leaves, tea residue and tea soup, respectively; those of soluble, organic, inorganic, Sb(III) and Sb(V) are 0.41, 0.11, 0.29, 0.21 and 0.07 ng mL- 1 in the tea soup, respectively. A certified reference material of tea leaves (GBW 07605) was analyzed by this method with satisfactory results.

Proceedings of the Annual Meeting of the Association for Education in Journalism and Mass Communication (83rd, Phoenix, Arizona, August 9-12, 2000). Miscellaneous, Part III.

ERIC Educational Resources Information Center

Association for Education in Journalism and Mass Communication.

The Miscellaneous, part III section of the proceedings contains the following 11 papers: "The Relationship between Health and Fitness Magazine Reading and Eating-Disordered Weight-Loss Methods among High School Girls" (Steven R. Thomsen, Michelle M. Weber, and Lora Beth Brown); "A Practical Exercise for Teaching Ethical Decision…

Analysis of Item-Level Bias in the Bayley-III Language Subscales: The Validity and Utility of Standardized Language Assessment in a Multilingual Setting

ERIC Educational Resources Information Center

Goh, Shaun K. Y.; Tham, Elaine K. H.; Magiati, Iliana; Sim, Litwee; Sanmugam, Shamini; Qiu, Anqi; Daniel, Mary L.; Broekman, Birit F. P.; Rifkin-Graboi, Anne

2017-01-01

Purpose: The purpose of this study was to improve standardized language assessments among bilingual toddlers by investigating and removing the effects of bias due to unfamiliarity with cultural norms or a distributed language system. Method: The Expressive and Receptive Bayley-III language scales were adapted for use in a multilingual country…

The "g" Factor and Cognitive Test Session Behavior: Using a Latent Variable Approach in Examining Measurement Invariance Across Age Groups on the WJ III

ERIC Educational Resources Information Center

Frisby, Craig L.; Wang, Ze

2016-01-01

Data from the standardization sample of the Woodcock-Johnson Psychoeducational Battery--Third Edition (WJ III) Cognitive standard battery and Test Session Observation Checklist items were analyzed to understand the relationship between g (general mental ability) and test session behavior (TSB; n = 5,769). Latent variable modeling methods were used…

Efficiency of compensatory orthodontic treatment of mild Class III malocclusion with two different bracket systems

PubMed Central

Aragón, Mônica L. C.; Bichara, Lívia M.; Flores-Mir, Carlos; Almeida, Guilherme; Normando, David

2017-01-01

ABSTRACT Objective: The purpose of this study was to assess the efficiency of compensatory orthodontic treatment of patients with mild Class III malocclusion with two preadjusted bracket systems. Method: Fifty-six matched patients consecutively treated for mild Class III malocclusion through compensatory dentoalveolar movements were retrospectively evaluated after analysis of orthodontic records. The sample was divided into two groups according to the brackets used: Group 1 = non-Class III compensated preadjusted brackets, Roth prescription (n = 28); Group 2 = compensated Class III preadjusted brackets, Capelozza III prescription (n = 28). Cephalometric analysis, number of appointments and missed appointments, months using Class III elastics, and bond/band failures were considered. Treatment time, Peer Assessment Rating (PAR) index at the beginning (PAR T1) and end of treatment (PAR T2) were used to calculate treatment efficiency. Comparison was performed using a MANOVA at p< 0.05. Results: Missed appointments, bond or band failures, number of months using the Class III intermaxillary elastics, and cephalometric measurements showed no statistically significant difference (p> 0.05) between groups. Patients treated with Roth brackets had a treatment time 7 months longer (p= 0.01). Significant improvement in the patient’s occlusion (PAR T2-T1) was observed for both groups without difference (p= 0.22). Conclusions: Orthodontic brackets designed for compensation of mild Class III malocclusions appear to be more efficient than non-compensated straight-wire prescription brackets. Treatment time for Class III patients treated with brackets designed for compensation was shorter than with Roth prescription and no difference in the quality of the occlusal outcome was observed. A prospective randomized study is suggested to provide a deeper look into this subject. PMID:29364379

Simultaneous determination of Cr(III) and Cr(VI) in tannery wastewater using low pressure ion chromatography combined with flow injection spectrophotometry

NASA Astrophysics Data System (ADS)

Chen, Shujuan; Zhang, Xinshen; Yu, Lingyun; Wang, Li; Li, Hui

2012-03-01

Trivalent and hexavalent chromium have been successfully separated and determined using low pressure ion chromatography combined with flow injection spectrophotometric analysis (LPIC-FIA). A column packed with crosslinking starch microspheres was used for on-line separation of Cr(III) from Cr(VI) in a flow-injection system because of its absorptive effect on Cr(III). To determine the concentration of Cr(III) and Cr(VI) in samples, we used 3.0 mmol/L nitric acid to elute adsorbed Cr(III) from the column and then used ceric sulfate-sulfuric acid as oxidant to convert all Cr(III) into Cr(VI). Then, Cr(VI) directly came from the samples and Cr(VI) came from Cr(III) successively formed a amaranthine complex with diphenycarbazide and the complex shows a maximum absorption at 530 nm. Analytical parameters including the concentration of eluent and oxidant solution, oxidizing temperature, length of oxidizing reaction coil, reaction coil and injection coil, interfering effects, etc., were optimized. The limit of detection was 1.25 μg/L for Cr(VI) and 3.76 μg/L for Cr(III). The linear relationship between absorption with the concentration of Cr(VI) and Cr(III) was 0.001-1.000 mg/L and 0.030-1.000 mg/L with correlation coefficients of 0.9995 and 0.9994, respectively. The relative standard deviation of Cr(VI) and Cr(III) was 1.21% and 1.66%, respectively (n = 10). Major cations and anions did not show any interference. We validated this method through certified reference materials and through measuring the recovery in tannery wastewater.

Targeted delivery of doxorubicin into tumor cells by nanostructured lipid carriers conjugated to anti-EGFRvIII monoclonal antibody.

PubMed

Abdolahpour, Saeideh; Toliyat, Tayebeh; Omidfar, Kobra; Modjtahedi, Helmout; Wong, Albert J; Rasaee, Mohammad Javad; Kashanian, Susan; Paknejad, Maliheh

2018-02-01

Epidermal growth factor receptor variant III (EGFRvIII) is the most common variant of the EGF receptor in many human tumors. This variant is tumor specific and highly immunogenic, thus, it can be used as a target for targeted drug delivery toward tumor cells. The major aim of this study was to develop an EGFRvIII-mediated drug delivery system by anti-EGFRvIII monoclonal antibody (MAb) conjugated to doxorubicin (Dox)-loaded nanostructured lipid carriers (NLC) to enhance the targeting specificity and cytotoxic effect of Dox on EGFRvIII-overexpressing cell line. In our study, Dox was chosen as a hydrophobic cytotoxic drug and drug-loaded nanostructured lipid carriers (Dox-NLC) was prepared by solvent emulsification/evaporation method. In order to conjugate anti-EGFRvIII MAb to Dox-NLC, DSPE-PEG2000-NHS (1,2-distearoylphosphatidylethanolamine-polyethylene glycol 2000-NHS) was used as a linker. Physicochemical characteristics of antibody conjugated Dox-NLC (MAb-Dox-NLC), including particle size, zeta potential, entrapment efficiency and in vitro Dox release were investigated. Cytotoxicity of MAb-Dox-NLC against NIH-3T3 and HC2 20d2/c (EGFRvIII-transfected NIH-3T3) cell lines was evaluated. The MAb-Dox-NLC appeared to enhance the cytotoxic activity of targeted NLC against HC2 20d2/c cells. The cellular uptake percentage of targeted NLC by HC2 20d2/c cells was higher than that of NIH-3T3 cells, indicating that EGFRvIII can specifically target HC2 20d2/c cells. In conclusion, anti-EGFRvIII MAb-targeted NLC may be considered as an effective nanocarrier for targeted drug delivery.

Thermal Modeling Method Improvements for SAGE III on ISS

NASA Technical Reports Server (NTRS)

Liles, Kaitlin; Amundsen, Ruth; Davis, Warren; McLeod, Shawn

2015-01-01

The Stratospheric Aerosol and Gas Experiment III (SAGE III) instrument is the fifth in a series of instruments developed for monitoring aerosols and gaseous constituents in the stratosphere and troposphere. SAGE III will be delivered to the International Space Station (ISS) via the SpaceX Dragon vehicle. A detailed thermal model of the SAGE III payload, which consists of multiple subsystems, has been developed in Thermal Desktop (TD). Many innovative analysis methods have been used in developing this model; these will be described in the paper. This paper builds on a paper presented at TFAWS 2013, which described some of the initial developments of efficient methods for SAGE III. The current paper describes additional improvements that have been made since that time. To expedite the correlation of the model to thermal vacuum (TVAC) testing, the chambers and GSE for both TVAC chambers at Langley used to test the payload were incorporated within the thermal model. This allowed the runs of TVAC predictions and correlations to be run within the flight model, thus eliminating the need for separate models for TVAC. In one TVAC test, radiant lamps were used which necessitated shooting rays from the lamps, and running in both solar and IR wavebands. A new Dragon model was incorporated which entailed a change in orientation; that change was made using an assembly, so that any potential additional new Dragon orbits could be added in the future without modification of the model. The Earth orbit parameters such as albedo and Earth infrared flux were incorporated as time-varying values that change over the course of the orbit; despite being required in one of the ISS documents, this had not been done before by any previous payload. All parameters such as initial temperature, heater voltage, and location of the payload are defined based on the case definition. For one component, testing was performed in both air and vacuum; incorporating the air convection in a submodel that was only built for the in-air cases allowed correlation of all testing to be done in a single model. These modeling improvements and more will be described and illustrated in the paper.

Electronic Structure and Properties of Berkelium Iodates.

PubMed

Silver, Mark A; Cary, Samantha K; Garza, Alejandro J; Baumbach, Ryan E; Arico, Alexandra A; Galmin, Gregory A; Chen, Kuan-Wen; Johnson, Jason A; Wang, Jamie C; Clark, Ronald J; Chemey, Alexander; Eaton, Teresa M; Marsh, Matthew L; Seidler, Kevin; Galley, Shane S; van de Burgt, Lambertus; Gray, Ashley L; Hobart, David E; Hanson, Kenneth; Van Cleve, Shelley M; Gendron, Frédéric; Autschbach, Jochen; Scuseria, Gustavo E; Maron, Laurent; Speldrich, Manfred; Kögerler, Paul; Celis-Barros, Cristian; Páez-Hernández, Dayán; Arratia-Pérez, Ramiro; Ruf, Michael; Albrecht-Schmitt, Thomas E

2017-09-27

The reaction of 249 Bk(OH) 4 with iodate under hydrothermal conditions results in the formation of Bk(IO 3 ) 3 as the major product with trace amounts of Bk(IO 3 ) 4 also crystallizing from the reaction mixture. The structure of Bk(IO 3 ) 3 consists of nine-coordinate Bk III cations that are bridged by iodate anions to yield layers that are isomorphous with those found for Am III , Cf III , and with lanthanides that possess similar ionic radii. Bk(IO 3 ) 4 was expected to adopt the same structure as M(IO 3 ) 4 (M = Ce, Np, Pu), but instead parallels the structural chemistry of the smaller Zr IV cation. Bk III -O and Bk IV -O bond lengths are shorter than anticipated and provide further support for a postcurium break in the actinide series. Photoluminescence and absorption spectra collected from single crystals of Bk(IO 3 ) 4 show evidence for doping with Bk III in these crystals. In addition to luminescence from Bk III in the Bk(IO 3 ) 4 crystals, a broad-band absorption feature is initially present that is similar to features observed in systems with intervalence charge transfer. However, the high-specific activity of 249 Bk (t 1/2 = 320 d) causes oxidation of Bk III and only Bk IV is present after a few days with concomitant loss of both the Bk III luminescence and the broadband feature. The electronic structure of Bk(IO 3 ) 3 and Bk(IO 3 ) 4 were examined using a range of computational methods that include density functional theory both on clusters and on periodic structures, relativistic ab initio wave function calculations that incorporate spin-orbit coupling (CASSCF), and by a full-model Hamiltonian with spin-orbit coupling and Slater-Condon parameters (CONDON). Some of these methods provide evidence for an asymmetric ground state present in Bk IV that does not strictly adhere to Russel-Saunders coupling and Hund's Rule even though it possesses a half-filled 5f 7 shell. Multiple factors contribute to the asymmetry that include 5f electrons being present in microstates that are not solely spin up, spin-orbit coupling induced mixing of low-lying excited states with the ground state, and covalency in the Bk IV -O bonds that distributes the 5f electrons onto the ligands. These factors are absent or diminished in other f 7 ions such as Gd III or Cm III .

An exonuclease III and graphene oxide-aided assay for DNA detection.

PubMed

Peng, Lu; Zhu, Zhi; Chen, Yan; Han, Da; Tan, Weihong

2012-05-15

We have developed a novel DNA assay based on exonuclease III (ExoIII)-induced target recycling and the fluorescence quenching ability of graphene oxide (GO). This assay consists of a linear DNA probe labeled with a fluorophore in the middle. Introduction of target sequence induces the exonuclease III catalyzed probe digestion and generation of single nucleotides. After each cycle of digestion, the target is recycled to realize the amplification. Finally, graphene oxide is added to quench the remaining probes and the signal from the resulting fluorophore labeled single nucleotides is detected. With this approach, a sub-picomolar detection limit can be achieved within 40 min at 37°C. The method was successfully applied to multicolor DNA detection and the analysis of telomerase activity in extracts from cancer cells. Copyright © 2012 Elsevier B.V. All rights reserved.

Extractive photometric determination of gold(III) with 1-(2',4',6'-trichlorophenyl)-4,4,6-trimethyl-(1H,4H)-2-pyrimidinethiol in presence of tri-iso-octylamine.

PubMed

Amuse, M A; Kuchekar, S R; Mote, N A; Chavan, M B

1985-10-01

Tervalent gold was determined spectrophotometrically as its anionic 1:4 gold-thiol complex extracted into chloroform from aqueous acidic medium (1.5M sulphuric acid) in the presence of tri-iso-octylamine. The complex exhibits maximum absorption at 480 nm (molar absorptivity 4.60 x 10(3) l.mole(-1).cm(-1)) and Beer's law is obeyed in the concentration range 5-50 microg of gold(III) per ml. The relative standard deviation and relative error, calculated from ten determinations of solutions containing 15 microg of gold(III) per ml were 1.0% and 0.8%. The method is simple, selective and reproducible. It permits separation of gold(III) from associated elements and its determination in synthetic mixtures.

Binding study of lysozyme with Al(III) using chemiluminescence analysis.

PubMed

Liu, Jiangman; Luo, Kai; Song, Zhenghua

2014-09-01

The binding behavior of lysozyme with Al(III) is described using luminol as a luminescence probe by flow injection-chemiluminescence (FI-CL) analysis. It was found that the CL intensity of the luminol-lysozyme reaction could be markedly enhanced by Al(III), and the increase in CL intensity was linear with the Al(III) concentration over the range 0.3-30.0  pg  mL(-1) , with a detection limit of 0.1 pg  mL(-1) (3σ). Based on the interaction model of lysozyme with Al(III), lg[(I - I0 )/(2I0  - I)] = lgK + nlg[M], the binding constant K = 6.84 × 10(6)  L mol(-1) and the number of binding sites (n) = 0.76. The relative standard deviations were 3.2, 2.4 and 2.0% for 10.0, 20.0 and 30.0  pg  mL(-1) Al(III) (n = 7), respectively. This new method was successfully applied to continuous, quantitative monitoring of picogram level Al(III) in human saliva following oral intake of compound aluminum hydroxide tablets. It was found that Al(III) in saliva reached a maximum of 101.2  ng  mL(-1) at 3.0 h. The absorption rate constant ka , elimination rate constant k and half-life time t1/2 of Al(III) were 1.378  h(-1) , 0.264  h(-1) and 2.624  h, respectively. Copyright © 2013 John Wiley & Sons, Ltd.

Improved Wavelengths and Oscillator Strengths of Cr III, Co III, and Fe III

NASA Astrophysics Data System (ADS)

Smith, Peter L.; Smillie, D. G.; Pickering, J. C.; Blackwell-Whitehead, R. J.

2008-05-01

Improvements in the resolution, accuracy, and range of spectra obtained by state-of-the-art space- and ground-based astronomical spectrographs have demonstrated a need for corresponding improvements in atomic data. Transition wavelengths with uncertainties of 1 part in 10^7 and oscillator strengths (f-values) with uncertainties of 10 to 15% are needed to accurately interpret modern astrophysical spectra. Our focus has been on spectra of doubly ionized iron group elements that dominate the UV spectra of hot B stars. We report here completion of measurements on Cr III, Co III, Fe III made with a UV high resolution Fourier transform spectrometer (FTS) [J. C. Pickering, Vibrational Spectrosc. 29, 27 (2002)] with a typical wavelength/wavenumber uncertainty of a few parts in 10^8, supplemented by measurements were carried out at the US National Institute of Standards & Technology using their FTS and the Normal Incidence Vacuum (grating) Spectrograph (NIVS). The spectra were analyzed and line lists were produced to give calibrated line wavelengths and relative intensities. Measured wavelengths are, in many cases, an order of magnitude more accurate than previous measurements, and the energy level uncertainties are typically reduced by a factor or 3 more. Summaries of submitted papers on Cr III and Co III will be presented, as will work on improved wavelengths, energy levels, and oscillator strengths for Fe III. Limitations to the method and possible solutions will be discussed. This work is, or has been, supported in part by NASA Grant NAG5-12668; NASA inter-agency agreement W-10255; PPARC; the Royal Society of the UK; and by the Leverhulme Trust.

Design, synthesis, and herbicidal activity of novel substituted 3-(pyridin-2-yl)benzenesulfonamide derivatives.

PubMed

Xie, Yong; Chi, Hui-Wei; Guan, Ai-Ying; Liu, Chang-Ling; Ma, Hong-Juan; Cui, Dong-Liang

2014-12-31

A series of novel substituted 3-(pyridin-2-yl)benzenesulfonamide derivatives were designed and synthesized using 2-phenylpridines as the lead compound by intermediate derivatization methods in an attempt to obtain novel compound candidates for weed control. The herbicidal activity assay in glasshouse tests showed several compounds (II6, II7, II8, II9, II10, II11, III2, III3, III4, and III5) could efficiently control velvet leaf, youth-and-old age, barnyard grass, and foxtail at the 37.5 g/ha active substance. Especially, the activities of II6, II7, III2, and III4 were proved roughly equivalent to the saflufenacil and better than 95% sulcotrione at the same concentration. The result of the herbicidal activity assay in field tests demonstrated that II7 at 60 g/ha active substance could give the same effect as bentazon at 1440 g/ha active substance to control dayflower and nightshade, meanwhile II7 showed better activity than oxyfluorfen to control arrowhead and security to rice. The present work indicates that II7 may be a novel compound candidate for potential herbicide.

Study of Silver Nanoparticles Sensitized Fluorescence and Second-Order Scattering of Terbium(III)-Pefloxacin Mesylate Complex and Determination of Pefloxacin Mesylate

PubMed Central

Li, Aiyun; Song, Zhiqiang

2014-01-01

α-Keto acid of pefloxacin mesylate (PFLX) can form the complex with Terbium(III). The intramolecular energy from PFLX to Terbium(III) ion takes place when excited, and thus Terbium(III) excited state is formed and then emits the characteristic fluorescence of Terbium(III), locating at 490, 545, 580, and 620 nm. The second-order scattering (SOS) peak at 545 nm also appears for the complex with the exciting wavelength of 273 nm. When the silver nanoparticles are added to the system, the luminescence intensity at 545 nm greatly increased. So, with the adding of nanoparticles to the Terbium(III)-PFLX complex, not only is the intramolecular energy promoted but also the SOS intensity is enhanced. The experimental results show that it is the silver nanoparticles with certain size and certain concentration which can greatly enhance the fluorescence-SOS intensity, and the relative intensity at 545 nm is proportional to the amount of PFLX. Based on this phenomenon, a novel method for the determination of PFLX has been developed and applied to the determination of PFLX in capsule and serum samples. PMID:24892083

Process mining in oncology using the MIMIC-III dataset

NASA Astrophysics Data System (ADS)

Prima Kurniati, Angelina; Hall, Geoff; Hogg, David; Johnson, Owen

2018-03-01

Process mining is a data analytics approach to discover and analyse process models based on the real activities captured in information systems. There is a growing body of literature on process mining in healthcare, including oncology, the study of cancer. In earlier work we found 37 peer-reviewed papers describing process mining research in oncology with a regular complaint being the limited availability and accessibility of datasets with suitable information for process mining. Publicly available datasets are one option and this paper describes the potential to use MIMIC-III, for process mining in oncology. MIMIC-III is a large open access dataset of de-identified patient records. There are 134 publications listed as using the MIMIC dataset, but none of them have used process mining. The MIMIC-III dataset has 16 event tables which are potentially useful for process mining and this paper demonstrates the opportunities to use MIMIC-III for process mining in oncology. Our research applied the L* lifecycle method to provide a worked example showing how process mining can be used to analyse cancer pathways. The results and data quality limitations are discussed along with opportunities for further work and reflection on the value of MIMIC-III for reproducible process mining research.

Anion-exchange high-performance liquid chromatography of water-soluble chromium (VI) and chromium (III) complexes in biological materials.

PubMed

Suzuki, Y

1987-04-10

A high-performance anion-exchange liquid chromatograph coupled to visible-range (370 nm) and UV (280 nm) detectors and an atomic-absorption spectrometer allowed the rapid determination of CrVI and/or complexes of CrIII in rat plasma, erythrocyte lysate and liver supernatant treated with CrVI or CrIII in vitro. CrVI in the eluates was determined using both the visible-range detector and atomic-absorption spectrometer (AAS). The detection limits of CrVI in standard solutions using these methods were 2 and 5 ng (signal-to-noise ratio = 2), respectively. Separations of the biological components and of CrIII complexes were monitored by UV and AAS analyses, respectively. Time-related decreases of CrVI accompanied by increases in CrIII complexes were observed, indicating the reduction of CrVI by some of the biological components. The reduction rates were considerably higher in the liver supernatant and erythrocyte lysate than in the plasma. These results indicate that the anion-exchange high-performance liquid chromatographic system is useful for simultaneous determination of CrVI and CrIII complexes in biological materials.

CO Column Density and Extinction in the Chamaeleon II--III Dark-Cloud Complex

NASA Astrophysics Data System (ADS)

Hayakawa, Takahiro; Cambrésy, Laurent; Onishi, Toshikazu; Mizuno, Akira; Fukui, Yasuo

2001-12-01

We carried out 13CO (J = 1 -- 0) and C18O (J = 1 -- 0) observations of the Chamaeleon II--III dark-cloud complex with the NANTEN radio telescope. The column densities of both molecular isotopes were derived assuming LTE. The AV values were obtained by scaling the AV values that were derived using an adaptive-grid star-count method applied to the DENIS J-band data. We established the AV--CO isotope column-density relations in Cha II and III, and compared them with those in Cha I. The slopes of the AV--13CO relations for Cha II and III are steeper than that for Cha I. Those of the AV -- C18O relations are similar among the three clouds. The total column density ratio, N(13O) / N(C18O, in Cha I tends to be small compared with those in Cha II or Cha III; the ratios range from ~ 5 to ~ 25 at low extinction in Cha II and III, but at most ~ 10 in Cha I. We suggest that the increase of N(13CO) due to the 13CO formation process causes cloud-to-cloud variations in the AV -- N(13CO) correlation.

Quantitative determination of some pharmaceutical piperazine derivatives through complexation with iron(III) chloride.

PubMed

Abou-Attia, F M; Issa, Y M; Abdel-Gawad, F M; Abdel-Hamid, S M

2003-08-01

A simple, accurate and sensitive spectrophotometric method has been developed for the determination of three pharmaceutical piperazine derivatives, namely ketoconazole (KC), trimetazidine hydrochloride (TMH) and piribedil (PD). This method is based on the formation of yellow orange complexes between iron(III) chloride and the investigated drugs. The optimum reaction conditions, spectral characteristics, conditional stability constants and composition of the water soluble complexes have been established. The method permits the determination of KC, TMH and PD over a concentration range 1-15, 1-12 and 1-12 microg ml(-1), respectively. Sandell sensitivity is found to be 0.016, 0.013 and 0.013 microg cm(-2) for KC, TMH and PD, respectively. The method was sensitive, simple, reproducible and accurate within +/-1.5%. The method is applicable to the assay of the three drugs under investigation in different dosage forms and the results are in good agreement with those obtained by the official methods (USP and JP).

Spectrophotometric determination of sulphate in automotive fuel ethanol by sequential injection analysis using dimethylsulphonazo(III) reaction.

PubMed

de Oliveira, Fabio Santos; Korn, Mauro

2006-01-15

A sensitive SIA method was developed for sulphate determination in automotive fuel ethanol. This method was based on the reaction of sulphate with barium-dimethylsulphonazo(III) leading to a decrease on the magnitude of analytical signal monitored at 665 nm. Alcohol fuel samples were previously burned up to avoid matrix effects for sulphate determinations. Binary sampling and stop-flow strategies were used to increase the sensitivity of the method. The optimization of analytical parameter was performed by response surface method using Box-Behnker and central composite designs. The proposed sequential flow procedure permits to determine up to 10.0mg SO(4)(2-)l(-1) with R.S.D. <2.5% and limit of detection of 0.27 mg l(-1). The method has been successfully applied for sulphate determination in automotive fuel alcohol and the results agreed with the reference volumetric method. In the optimized condition the SIA system carried out 27 samples per hour.

40 CFR 60.704 - Test methods and procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... and hydrogen. (iii) Method 4 to measure the content of water vapor. (3) The volumetric flow rate shall... part) if published values are not available or cannot be calculated. Bws=Water vapor content of the...

40 CFR 60.704 - Test methods and procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... and hydrogen. (iii) Method 4 to measure the content of water vapor. (3) The volumetric flow rate shall... part) if published values are not available or cannot be calculated. Bws=Water vapor content of the...

Development of a Novel Human Single Chain Antibody Against EGFRVIII Antigen by Phage Display Technology.

PubMed

Rahbarnia, Leila; Farajnia, Safar; Babaei, Hossein; Majidi, Jafar; Akbari, Bahman; Ahdi Khosroshahi, Shiva

2016-12-01

Purpose: EGFRvIII as the most common mutant variant of the epidermal growth factor receptor is resulting from deletion of exons 2-7 in the coding sequence and junction of exons 1 and 8 through a novel glycine residue. EGFRvIII is highly expressed in glioblastoma, carcinoma of the breast, ovary, and lung but not in normal cells. The aim of the present study was identification of a novel single chain antibody against EGFRvIII as a promising target for cancer therapy. Methods: In this study, a synthetic peptide corresponding to EGFRvIII protein was used for screening a naive human scFv phage library. A novel five-round selection strategy was used for enrichment of rare specific clones. Results: After five rounds of screening, six positive scFv clones against EGFRvIII were selected using monoclonal phage ELISA, among them, only three clones had expected size in PCR reaction. The specific interaction of two of the scFv clones with EGFRvIII was confirmed by indirect ELISA. One phage clone with higher affinity in scFv ELISA was purified for further analysis. The purity of the produced scFv antibody was confirmed using SDS-PAGE and Western blotting analyses. Conclusion: In the present study, a human anti- EGFRvIII scFv with high affinity was first identified from a scFv phage library. This study can be the groundwork for developing more effective diagnostic and therapeutic agents against EGFRvIII expressing cancers.

Correleation of the SAGE III on ISS Thermal Models in Thermal Desktop

NASA Technical Reports Server (NTRS)

Amundsen, Ruth M.; Davis, Warren T.; Liles, Kaitlin, A. K.; McLeod, Shawn C.

2017-01-01

The Stratospheric Aerosol and Gas Experiment III (SAGE III) instrument is the fifth in a series of instruments developed for monitoring aerosols and gaseous constituents in the stratosphere and troposphere. SAGE III was launched on February 19, 2017 and mounted to the International Space Station (ISS) to begin its three-year mission. A detailed thermal model of the SAGE III payload, which consists of multiple subsystems, has been developed in Thermal Desktop (TD). Correlation of the thermal model is important since the payload will be expected to survive a three-year mission on ISS under varying thermal environments. Three major thermal vacuum (TVAC) tests were completed during the development of the SAGE III Instrument Payload (IP); two subsystem-level tests and a payload-level test. Additionally, a characterization TVAC test was performed in order to verify performance of a system of heater plates that was designed to allow the IP to achieve the required temperatures during payload-level testing; model correlation was performed for this test configuration as well as those including the SAGE III flight hardware. This document presents the methods that were used to correlate the SAGE III models to TVAC at the subsystem and IP level, including the approach for modeling the parts of the payload in the thermal chamber, generating pre-test predictions, and making adjustments to the model to align predictions with temperatures observed during testing. Model correlation quality will be presented and discussed, and lessons learned during the correlation process will be shared.

Current Evidence Regarding the Diagnostic Methods for Pediatric Lumbar Spondylolisthesis: A Report From the Scoliosis Research Society Evidence Based Medicine Committee.

PubMed

Kim, Han Jo; Crawford, Charles H; Ledonio, Charles; Bess, Shay; Larson, A Noelle; Gates, Marilyn; Oetgen, Matthew; Sanders, James O; Burton, Douglas

Structured literature review. The Scoliosis Research Society (SRS) requested an assessment of the current state of peer-reviewed evidence regarding pediatric lumbar spondylolisthesis with the goal of identifying what is known and what gaps remain in further understanding the diagnostic methods for pediatric spondylolisthesis. Spondylolisthesis in the lumbar spine is common among children and adolescents and no formal synthesis of the published literature regarding diagnostic methods has been previously performed. A comprehensive literature search was performed. Abstracts were reviewed and data from included studies were analyzed by the committee. From 6600 initial citations with abstract, 663 articles underwent full-text review. The best available evidence for the clinical questions regarding diagnostic methods was provided by 26 included studies. Six of the studies were graded as Level III (retrospective comparative), and represent the current best available evidence whereas 20 of the studies were graded as Level IV (retrospective case series) evidence. No Level V (expert opinion) studies were included in the final list. None of the studies were graded as Level I or Level II. Plain radiography is the workhorse imaging modality for diagnosing spondylolisthesis. No association between radiologic grade of spondylolisthesis and clinical presentation were noted; however, grade III and IV slips more often required surgery, and increasing slip angles were associated with worse baseline outcome scores. There is Level III evidence that the Meyerding grade appears to be more accurate for measuring slip percentage whereas the Lonstein Slip angle and Dubousset Lumbosacral Kyphosis angles are the best for measuring lumbosacral kyphosis in spondylolisthesis. In addition, higher sacral table index, pelvic incidence, sacral slope, and lower sacral table angle were associated with spondylolisthesis. True incidence could not be determined by the current literature available. However, studies in adolescent athletes demonstrated an incidence of 6% to 7% across studies. The current "best available" evidence to guide the diagnosis and characterization of pediatric spondylolisthesis is presented. Future studies are needed to provide more high-quality evidence to answer these clinically relevant questions. Level III, review of Level III studies. Copyright © 2017 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.

Solar cells based on InP/GaP/Si structure

NASA Astrophysics Data System (ADS)

Kvitsiani, O.; Laperashvil, D.; Laperashvili, T.; Mikelashvili, V.

2016-10-01

Solar cells (SCs) based on III-V semiconductors are reviewed. Presented work emphases on the Solar Cells containing Quantum Dots (QDs) for next-generation photovoltaics. In this work the method of fabrication of InP QDs on III-V semiconductors is investigated. The original method of electrochemical deposition of metals: indium (In), gallium (Ga) and of alloys (InGa) on the surface of gallium phosphide (GaP), and mechanism of formation of InP QDs on GaP surface is presented. The possibilities of application of InP/GaP/Si structure as SC are discussed, and the challenges arising is also considered.

[Surgical repair of complete acromioclavicular separation (Tossy III) by tension wire bending and suture of the ligaments (author's transl)].

PubMed

Meeder, P J; Wentzensen, A; Weise, K

1980-01-01

The diagnosis of a complete acromioclavicular separation (Tossy III) is a indication for a surgical repair. Many and different methods are reported in history. 33 patients with a fresh, complete acromioclavicular separation are treated at the BG-Unfallklinik Tübingen from 1. 1. 1970--31. 12. 1978 by suturing the ligaments, inserting pins across the joint and tension-bending. With this method good results have been achieved, possible intra- and postoperative complications are reported. The incision along the clavicula gives quite often scar problems. Therefore we now use an arched incision across the AC-joint.

Determination of trace arsenic on hanging copper amalgam drop electrode.

PubMed

Piech, Robert; Baś, Bogusław; Niewiara, Ewa; Kubiak, Władysław W

2007-04-30

Hanging copper amalgam drop electrode has been applied for trace determination of arsenic by cathodic stripping analysis. Detection limit for As(III) as low as 0.33nM (0.02mug/L) at deposition time (240s) could be obtained. For seven successive determinations of As(III) at concentration of 5nM relative standard deviation was 2.5% (n=7). Interferences from selected metals and surfactant substances were examined. Absence of copper ions in sample solution causes easier optimization and makes method less vulnerable on contamination. The developed method was validated by analysis of certified reference materials (CRMs) and applied to arsenic determinations in natural water samples.

[Research on chemical constituents from stem of Gymnema sylvestre].

PubMed

Zhen, Han-shen; Zhu, Xue-yan; Lu, Ru-mei; Liang, Jie; Qiu, Qin; Meng, Qi-miao

2008-08-01

To study on the chemical constituents from the stem of Gymnema sylvestre. The constituents were extracted by percolation with ethanol. Then the extract was separated by systemic solvent separation methods. The part of n-butanol extract was isolated and purified by macroporous adsorptive resins, silica gel column chromatography, sephadex gel column chromatography and recrystallization. The isolated compounds were identified by spectrum methods. Eight compounds were isolated and identified as fallows: Conduritol A(I), 1-Heptadecanol(II), Stigmasterol glucoside(III), 1-Quercitol(IV), 1-Octadecanol(V), Potassium nitrate(VI), Lupeol cinnamate(VII), Stigmasterol(VIII). Chemical compounds II, III, V, VII are firstly obtained from this plant.

Determination of ultra-trace aluminum in human albumin by cloud point extraction and graphite furnace atomic absorption spectrometry.

PubMed

Sun, Mei; Wu, Qianghua

2010-04-15

A cloud point extraction (CPE) method for the preconcentration of ultra-trace aluminum in human albumin prior to its determination by graphite furnace atomic absorption spectrometry (GFAAS) had been developed in this paper. The CPE method was based on the complex of Al(III) with 1-(2-pyridylazo)-2-naphthol (PAN) and Triton X-114 was used as non-ionic surfactant. The main factors affecting cloud point extraction efficiency, such as pH of solution, concentration and kind of complexing agent, concentration of non-ionic surfactant, equilibration temperature and time, were investigated in detail. An enrichment factor of 34.8 was obtained for the preconcentration of Al(III) with 10 mL solution. Under the optimal conditions, the detection limit of Al(III) was 0.06 ng mL(-1). The relative standard deviation (n=7) of sample was 3.6%, values of recovery of aluminum were changed from 92.3% to 94.7% for three samples. This method is simple, accurate, sensitive and can be applied to the determination of ultra-trace aluminum in human albumin. 2009 Elsevier B.V. All rights reserved.

Thallium release from acid mine drainages: Speciation in river and tap water from Valdicastello mining district (northwest Tuscany).

PubMed

Campanella, Beatrice; Casiot, Corinne; Onor, Massimo; Perotti, Martina; Petrini, Riccardo; Bramanti, Emilia

2017-08-15

In this work we present an advantageous method for the simultaneous separation and detection of Tl(I) and Tl(III) species through ion chromatography coupled with on-line inductively coupled plasma - mass spectrometry. Chromatographic separation between Tl(III) and Tl(I) was achieved in less than two minutes. The method was validated by recovery experiments on real samples, and by comparing the sum of the concentrations of individual Tl species with total thallium values obtained from continuous flow ICP-MS. The experimental procedure offers an accurate, sensitive and interference-free method for Tl speciation at trace levels in environmental samples. This allowed us to investigate the Tl speciation in acid mine drainages (AMD), surface waters and springs in a mining catchment in Valdicastello Carducci (Tuscany, Italy), where severe Tl contamination ad been evidenced previously. This study shows for the first time that Tl(III), in addition to Tl(I), is present in considerable amounts in water samples affected by acid mining outflow, raising the question of the origin of this thermodynamically unstable species. Copyright © 2017 Elsevier B.V. All rights reserved.

26 CFR 1.472-2 - Requirements incident to adoption and use of LIFO inventory method.

Code of Federal Regulations, 2012 CFR

2012-04-01

... inventory method. (ii) Any method of establishing pools for inventory under the dollar-value LIFO inventory method. (iii) Any method of determining the LIFO value of a dollar-value inventory pool, such as the... selecting a price index to be used with the index or link chain method of valuing inventory pools under the...

40 CFR 52.126 - Control strategy and regulations: Particulate matter.

Code of Federal Regulations, 2010 CFR

2010-07-01

... be determined by using method 2 and traversing according to method 1. Gas analysis shall be performed using the integrated sample technique of method 3, and moisture content shall be determined by the condenser technique of method 4. (iii) All tests shall be conducted while the source is operating at the...

Reversed Phase Column HPLC-ICP-MS Conditions for Arsenic Speciation Analysis of Rice Flour.

PubMed

Narukawa, Tomohiro; Matsumoto, Eri; Nishimura, Tsutomu; Hioki, Akiharu

2015-01-01

New measurement conditions for arsenic speciation analysis of rice flour were developed using HPLC-ICP-MS equipped with a reversed phase ODS column. Eight arsenic species, namely, arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMAA), dimethylarsinic acid (DMAA), trimethylarsine oxide (TMAO), tetramethylarsonium (TeMA), arsenobetaine (AsB) and arsenocholine (AsC), were separated and determined under the proposed conditions. In particular, As(III) and MMAA and DMAA and AsB were completely separated using a newly proposed eluent containing ammonium dihydrogen phosphate. Importantly, the sensitivity changes, in particular those of As(V) and As(III) caused by coexisting elements and by complex matrix composition, which had been problematical in previously reported methods, were eliminated. The new eluent can be applied to C8, C18 and C30 ODS columns with the same effectiveness and with excellent repeatability. The proposed analytical method was successfully applied to extracts of rice flour certified reference materials.

Comparative acute toxicity of gallium(III), antimony(III), indium(III), cadmium(II), and copper(II) on freshwater swamp shrimp (Macrobrachium nipponense).

PubMed

Yang, Jen-Lee

2014-04-01

Acute toxicity testing were carried out the freshwater swamp shrimp, Macrobrachium nipponense, as the model animal for the semiconductor applied metals (gallium, antimony, indium, cadmium, and copper) to evaluate if the species is an suitable experimental animal of pollution in aquatic ecosystem. The static renewal test method of acute lethal concentrations determination was used, and water temperature was maintained at 24.0 ± 0.5°C. Data of individual metal obtained from acute toxicity tests were determined using probit analysis method. The median lethal concentration (96-h LC50) of gallium, antimony, indium, cadmium, and copper for M. nipponense were estimated as 2.7742, 1.9626, 6.8938, 0.0539, and 0.0313 mg/L, respectively. Comparing the toxicity tolerance of M. nipponense with other species which exposed to these metals, it is obviously that the M. nipponense is more sensitive than that of various other aquatic animals.

A literature review of applied adaptive design methodology within the field of oncology in randomised controlled trials and a proposed extension to the CONSORT guidelines.

PubMed

Mistry, Pankaj; Dunn, Janet A; Marshall, Andrea

2017-07-18

The application of adaptive design methodology within a clinical trial setting is becoming increasingly popular. However the application of these methods within trials is not being reported as adaptive designs hence making it more difficult to capture the emerging use of these designs. Within this review, we aim to understand how adaptive design methodology is being reported, whether these methods are explicitly stated as an 'adaptive design' or if it has to be inferred and to identify whether these methods are applied prospectively or concurrently. Three databases; Embase, Ovid and PubMed were chosen to conduct the literature search. The inclusion criteria for the review were phase II, phase III and phase II/III randomised controlled trials within the field of Oncology that published trial results in 2015. A variety of search terms related to adaptive designs were used. A total of 734 results were identified, after screening 54 were eligible. Adaptive designs were more commonly applied in phase III confirmatory trials. The majority of the papers performed an interim analysis, which included some sort of stopping criteria. Additionally only two papers explicitly stated the term 'adaptive design' and therefore for most of the papers, it had to be inferred that adaptive methods was applied. Sixty-five applications of adaptive design methods were applied, from which the most common method was an adaptation using group sequential methods. This review indicated that the reporting of adaptive design methodology within clinical trials needs improving. The proposed extension to the current CONSORT 2010 guidelines could help capture adaptive design methods. Furthermore provide an essential aid to those involved with clinical trials.

1967-1968 Project Reports by Faculty Members of San Joaquin Delta College: A Project under Title III, Higher Education Act of 1965.

ERIC Educational Resources Information Center

Bullard, Richard F., Ed.

These 17 curriculum studies by faculty members of San Joaquin Delta Junior College were funded under Title III of The Higher Education Act of 1965. They were intended to help initiate new courses, improve existing ones, or plan for future ones. Each project report gave its objective(s), the general methods for its development and completion, the…

The Effect of Temperature and Ionic Strength on the Oxidation of Iodide by Iron(III): A Clock Reaction Kinetic Study

ERIC Educational Resources Information Center

Bauer, Jurica; Tomisic, Vladislav; Vrkljan, Petar B. A.

2012-01-01

A laboratory exercise has recently been reported in which the students use the initial rates method based on the clock reaction approach to deduce the rate law and propose a reaction mechanism for the oxidation of iodide by iron(III) ions. The same approach is used in the exercise proposed herein; the students determine the dependence of the…

Purification of preparative quantities of group B Streptococcus type III oligosaccharides.

PubMed

Paoletti, L C; Johnson, K D

1995-06-30

Many bacterial capsular polysaccharides are regularly repeating units of oligosaccharides. Bacterial oligosaccharides have been used in neoglycoconjugate vaccines and as reagents in the study of specific antibody binding. Unfortunately, separation methods have not been adequate for the purification of preparative quantities of bacterial oligosaccharides. Here we describe a size-exclusion procedure that resulted in the resolution of group B Streptococcus type III oligosaccharides composed of 4-25 sugars.

Assessing child belt fit, volume II : effect of restraint configuration, booster seat designs, seating procedure, and belt fit on the dynamic response of the hybrid III 10-year-old ATD in sled tests.

DOT National Transportation Integrated Search

2008-09-01

A total of 49 dynamic sled tests were performed with the Hybrid III 10YO to examine issues relating to child belt fit. The goals of these tests were to evaluate ATD response to realistic belt geometries and belt fit, develop methods for accurate, rep...

A highly sensitive and selective electrochemical sensor for determination of Cr(VI) in the presence of Cr(III) using modified multi-walled carbon nanotubes/quercetin screen-printed electrode.

PubMed

Sadeghi, Susan; Garmroodi, Aziz

2013-12-01

A novel screen-printed carbon electrode modified with quercetin/multi-walled carbon nanotubes was fabricated for determination of Cr(VI) in the presence of excess of Cr(III) without any pretreatment. The method is based on accumulation of the quercetin-Cr(III) complex generated in situ from Cr(VI) at the modified electrode surface in an open circuit followed by differential pulse voltammetry detection. The new method allowed selective determination of Cr(VI) in the presence of Cr(III). The influence of various parameters affecting the adsorptive stripping voltammetry performance was investigated. Under the optimum conditions, the calibration plot was found to be linear in the Cr(VI) concentration range from 1.0 to 200 μmol(-1) with a limit of detection(S/N=3) of 0.3 μmol L(-1). The relative standard deviation (RSD%) of seven replicates of the current measurements for a 50 μmol(-1) of Cr(VI) solution was 3.0%. The developed electrode displayed a very low or no sensitivity to alkali, alkali-earth and transition metal cations and was successfully applied for the determination of Cr(VI) in drinking water samples. © 2013.

[Triple no loop Endobutton plate combined with Orthcord line for the treatment of acromioclavicular dislocation of Tossy type III].

PubMed

Xia, Ming-Hua; Xie, Shui-Hua; Wu, Jun; Zhang, Wen-Qing; Chen, Wei-Dong; He, Jian-Hua; Ding, Hao; Hu, Qian-Qin; Wang, Xiao-Peng

2016-07-25

To explore the clinical effects of the triple no loop Endobutton plate combined with Orthcord line in treating acromioclavicular dislocation of Tossy type III. Between February 2011 and September 2013, 36 patients with acromioclavicular dislocation of Tossy type III were treated with triple no loop Endobutton plate and Orthcord line. There were 21 males and 15 females, aged from 9 to 48 years old with an average of (26.41±14.05) years. Couse of disease was from 2 to 7 days in the patients. The patients had the clinical manifestations such as shoulder pain, extension limited, acromioclavicular tenderness, positive organ point sign. Clinical effects were assessed by acromioclavicular scoring system. Thirty six patients were followed up from 8 to 15 months with an average of (12.2±4.3) months. All incisions got primary healing. At the final follow up, all shoulder pain vanished, acromioclavicular joints without tenderness, negative organ point sign. No redislocation and steel plate loosening were found. According to the acromioclavicular scoring system, 31 cases obtained excellent results, 5 good. The method of triple no loop Endobutton plate combined with Orthcord line for acromioclavicular dislocation of Tossy type III has advantage of less risk and complication, good functional rehabilitation and is an ideal method.

Comparison of APACHE III, APACHE IV, SAPS 3, and MPM0III and Influence of Resuscitation Status on Model Performance

PubMed Central

Gajic, Ognjen; Afessa, Bekele

2012-01-01

Background: There are few comparisons among the most recent versions of the major adult ICU prognostic systems (APACHE [Acute Physiology and Chronic Health Evaluation] IV, Simplified Acute Physiology Score [SAPS] 3, Mortality Probability Model [MPM]0III). Only MPM0III includes resuscitation status as a predictor. Methods: We assessed the discrimination, calibration, and overall performance of the models in 2,596 patients in three ICUs at our tertiary referral center in 2006. For APACHE and SAPS, the analyses were repeated with and without inclusion of resuscitation status as a predictor variable. Results: Of the 2,596 patients studied, 283 (10.9%) died before hospital discharge. The areas under the curve (95% CI) of the models for prediction of hospital mortality were 0.868 (0.854-0.880), 0.861 (0.847-0.874), 0.801 (0.785-0.816), and 0.721 (0.704-0.738) for APACHE III, APACHE IV, SAPS 3, and MPM0III, respectively. The Hosmer-Lemeshow statistics for the models were 33.7, 31.0, 36.6, and 21.8 for APACHE III, APACHE IV, SAPS 3, and MPM0III, respectively. Each of the Hosmer-Lemeshow statistics generated P values < .05, indicating poor calibration. Brier scores for the models were 0.0771, 0.0749, 0.0890, and 0.0932, respectively. There were no significant differences between the discriminative ability or the calibration of APACHE or SAPS with and without “do not resuscitate” status. Conclusions: APACHE III and IV had similar discriminatory capability and both were better than SAPS 3, which was better than MPM0III. The calibrations of the models studied were poor. Overall, models with more predictor variables performed better than those with fewer. The addition of resuscitation status did not improve APACHE III or IV or SAPS 3 prediction. PMID:22499827

19 CFR 152.103 - Transaction value.

Code of Federal Regulations, 2010 CFR

2010-04-01

... actually paid or payable will be considered without regard to its method of derivation. It may be the... accounting principles. The method of apportionment actually accepted by Customs will depend upon the... of the first shipment, or (iii) the entire anticipated production. In addition to these three methods...

14 CFR 121.414 - Initial and transition training and checking requirements: flight instructors (airplane), flight...

Code of Federal Regulations, 2012 CFR

2012-01-01

... teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor-student... policies and procedures. (3) The appropriate methods, procedures, and techniques for conducting flight...) The corrective action in the case of unsatisfactory training progress. (6) The approved methods...

14 CFR 121.414 - Initial and transition training and checking requirements: flight instructors (airplane), flight...

Code of Federal Regulations, 2011 CFR

2011-01-01

... teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor-student... policies and procedures. (3) The appropriate methods, procedures, and techniques for conducting flight...) The corrective action in the case of unsatisfactory training progress. (6) The approved methods...

14 CFR 121.414 - Initial and transition training and checking requirements: flight instructors (airplane), flight...

Code of Federal Regulations, 2013 CFR

2013-01-01

... teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor-student... policies and procedures. (3) The appropriate methods, procedures, and techniques for conducting flight...) The corrective action in the case of unsatisfactory training progress. (6) The approved methods...

14 CFR 121.414 - Initial and transition training and checking requirements: flight instructors (airplane), flight...

Code of Federal Regulations, 2010 CFR

2010-01-01

... teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor-student... policies and procedures. (3) The appropriate methods, procedures, and techniques for conducting flight...) The corrective action in the case of unsatisfactory training progress. (6) The approved methods...

26 CFR 1.168(i)-5 - Table of contents.

Code of Federal Regulations, 2010 CFR

2010-04-01

... period. (ii) Shorter recovery period. (iii) Less accelerated depreciation method. (iv) More accelerated... in the year of replacement. (i) In general. (ii) Applicable recovery period, depreciation method, and... acquired property. (3) Recovery period and/or depreciation method of the properties are the same, or both...

26 CFR 1.168(i)-5 - Table of contents.

Code of Federal Regulations, 2012 CFR

2012-04-01

... period. (ii) Shorter recovery period. (iii) Less accelerated depreciation method. (iv) More accelerated... in the year of replacement. (i) In general. (ii) Applicable recovery period, depreciation method, and... acquired property. (3) Recovery period and/or depreciation method of the properties are the same, or both...

26 CFR 1.168(i)-5 - Table of contents.

Code of Federal Regulations, 2011 CFR

2011-04-01

... period. (ii) Shorter recovery period. (iii) Less accelerated depreciation method. (iv) More accelerated... in the year of replacement. (i) In general. (ii) Applicable recovery period, depreciation method, and... acquired property. (3) Recovery period and/or depreciation method of the properties are the same, or both...

26 CFR 1.168(i)-5 - Table of contents.

Code of Federal Regulations, 2013 CFR

2013-04-01

... period. (ii) Shorter recovery period. (iii) Less accelerated depreciation method. (iv) More accelerated... in the year of replacement. (i) In general. (ii) Applicable recovery period, depreciation method, and... acquired property. (3) Recovery period and/or depreciation method of the properties are the same, or both...

26 CFR 1.168(i)-5 - Table of contents.

Code of Federal Regulations, 2014 CFR

2014-04-01

... period. (ii) Shorter recovery period. (iii) Less accelerated depreciation method. (iv) More accelerated... in the year of replacement. (i) In general. (ii) Applicable recovery period, depreciation method, and... acquired property. (3) Recovery period and/or depreciation method of the properties are the same, or both...

Comparisons of LET distributions measured in low-earth orbit using tissue-equivalent proportional counters and the position-sensitive silicon-detector telescope (RRMD-III)

NASA Technical Reports Server (NTRS)

Doke, T.; Hayashi, T.; Borak, T. B.; Chatterjee, A. (Principal Investigator)

2001-01-01

Determinations of the LET distribution, phi(L), of charged particles within a spacecraft in low-Earth orbit have been made. One method used a cylindrical tissue-equivalent proportional counter (TEPC), with the assumption that for each measured event, lineal energy, y, is equal to LET and thus phi(L) = phi(y). The other was based on the direct measurement of LETs for individual particles using a charged-particle telescope consisting of position-sensitive silicon detectors called RRMD-III. There were differences of up to a factor of 10 between estimates of phi(L) using the two methods on the same mission. This caused estimates of quality factor to vary by a factor of two between the two methods.

40 CFR 60.675 - Test methods and procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (e.g., road dust). The required observer position relative to the sun (Method 9 of Appendix A-4 of... that the proper sun position can be maintained for all three points. (iii) If an opacity reading for...

40 CFR 60.675 - Test methods and procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (e.g., road dust). The required observer position relative to the sun (Method 9 of Appendix A-4 of... that the proper sun position can be maintained for all three points. (iii) If an opacity reading for...

40 CFR 60.675 - Test methods and procedures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (e.g., road dust). The required observer position relative to the sun (Method 9 of Appendix A-4 of... that the proper sun position can be maintained for all three points. (iii) If an opacity reading for...

40 CFR 60.675 - Test methods and procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (e.g., road dust). The required observer position relative to the sun (Method 9 of Appendix A-4 of... that the proper sun position can be maintained for all three points. (iii) If an opacity reading for...

Thrust Chamber Material Technology Program

DTIC Science & Technology

1989-03-01

about 5 percent lower than those of NASA.Z. Alloy 1035 was essentially equivalent to NASA-Z. However, Alloy 1032, containing titanium, exhibited such...Characterization Methods .................................... 33 5 Evaluation Methods ......................................................... 37 III...115 5 Discussion ..................................................................... 120 V ALLOY CHARACTERIZATION

Chromium(III) release from chromium‐tanned leather elicits allergic contact dermatitis: a use test study

PubMed Central

Erfani, Behnaz; Matura, Mihály; Lidén, Carola

2018-01-01

Summary Background Chromium (Cr) is a common skin sensitizer. The use of Cr(VI) in leather is restricted in the EU, but that of Cr(III) is not. Objectives To assess whether prolonged exposure to Cr‐tanned leather with mainly Cr(III) release may elicit allergic contact dermatitis in Cr‐allergic individuals. Method Ten Cr‐allergic subjects and 22 controls were patch tested with serial dilutions of Cr(III) and Cr(VI), and with leather samples. They then conducted a use test with a Cr‐tanned and a Cr‐free leather bracelet over a period of 3 weeks, for 12 h per day. Cr deposited on the skin from the bracelets was measured in the controls, and the diphenylcarbazide test for Cr(VI) and extraction tests for Cr(III) and Cr(VI) were conducted for the different leathers. Results Four of 10 Cr‐allergic subjects developed positive reactions to the Cr‐tanned bracelet within 7–21 days, whereas only 1 of 10 had a positive patch test reaction to this leather. Cr released from the Cr‐tanned leather was most probably entirely Cr(III), with a quantifiable amount being deposited on the skin. Conclusions This study strongly suggests that prolonged and repeated exposure to Cr‐tanned leather with mainly Cr(III) release is capable of eliciting allergic contact dermatitis in Cr‐allergic individuals. PMID:29322530

Molecular simulations reveal that the long range fluctuations of human DPP III change upon ligand binding.

PubMed

Tomić, A; Berynskyy, M; Wade, R C; Tomić, S

2015-11-01

The experimentally determined structures of human dipeptidyl peptidase III (DPP III) for the wild-type protein and for the complex of its E451A mutant with the peptide substrate, tynorphin, differ significantly in their overall shape. The two domains of the enzyme are separated by a wide cleft in the structure of the ligand-free enzyme, while in the ligand-bound mutant they are very close to each other, and the protein structure is extremely compact. Here, we applied a range of molecular dynamics simulation techniques to investigate the DPP III conformational landscape and the influence of ligand binding on the protein structure and dynamics. We used conventional, accelerated and steered methods to simulate DPP III and its complexes with tynorphin and with the preferred, synthetic, substrate Arg-Arg-2-naphthylamide. We found that DPP III can adopt a number of different forms in solution. The compact forms are more stable, but the open and partially closed states, spanning a wide range of conformations, can more effectively recognize the substrate which preferentially binds to the five-stranded β-core of the lower DPP III domain. The simulations indicated the existence of a dynamic equilibrium between open and semi-closed states and revealed two ways that the protein can close, leading to two distinct compact structures. The way in which the protein closes depends on the presence of the ligand.

Determination of sub-ng g-1 levels of total inorganic arsenic and selenium in foods by hydride-generation atomic absorption spectrometry after pre-concentration.

PubMed

Altunay, Nail; Gürkan, Ramazan

2017-03-01

A new and simple ultrasonic-assisted extraction (UAE) procedure was developed for the determination of inorganic arsenic and selenium in foods by hydride-generation atomic absorption spectrometry (HG-AAS). The various analytical variables affecting complex formation and extraction efficiency were investigated and optimised. The method is based on selective complex formation of As(III) and Se(IV) in the presence of excess As(V) and Se(VI) with toluidine red in the presence of tartaric acid at pH 4.5, and then extraction of the resulting condensation products into the micellar phase of non-ionic surfactant, polyethylene glycol dodecyl ether, Brij 35. Under optimised conditions, good linear relationships were obtained in the ranges of 4-225 and 12-400 ng l - 1 with limits of detection of 1.1 and 3.5 ng l - 1 for As(III) and Se(IV), respectively. The repeatability was better than 3.9% for both analytes (n = 10, 25 ng l - 1 ) while reproducibility ranged from 4.2% to 4.8%. The recoveries of As(III) and Se(IV) spiked at 25-100 ng l - 1 were in the range of 94.2-104.8%. After pre-concentration of a 5.0 ml sample, the sensitivity enhancement factors for As(III) and Se(IV) were 185 and 140, respectively. Accuracy was assessed by analysis of two standard reference materials (SRMs) and spiked recovery experiments. The method was successfully applied to the accurate and reliable determination of total As and total Se by HG-AAS after pre-reduction with a mixture of L-cysteine and tartaric acid. Finally, the method was shown to be rapid and sensitive, with good results for extraction, pre-concentration and determination of total As and Se contents (as As(III) and Se(IV)) from food samples.

Fabrication of patterned calcium cross-linked alginate hydrogel films and coatings through reductive cation exchange.

PubMed

Bruchet, Marion; Melman, Artem

2015-10-20

Calcium cross-linked alginate hydrogels are widely used in targeted drug delivery, tissue engineering, wound treatment, and other biomedical applications. We developed a method for preparing homogeneous alginate hydrogels cross-linked with Ca(2+) cations using reductive cation exchange in homogeneous iron(III) cross-linked alginate hydrogels. Treatment of iron(III) cross-linked alginate hydrogels with calcium salts and sodium ascorbate results in reduction of iron(III) cations to iron(II) that are instantaneously replaced with Ca(2+) cations, producing homogeneous ionically cross-linking hydrogels. Alternatively, the cation exchange can be performed by photochemical reduction in the presence of calcium chloride using a sacrificial photoreductant. This approach allows fabrication of patterned calcium alginate hydrogels through photochemical patterning of iron(III) cross-linked alginate hydrogel followed by the photochemical reductive exchange of iron cations to calcium. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis and antiviral bioactivities of 2-aryl- or 2-methyl-3-(substituted- benzalamino)-4(3H)-quinazolinone derivatives.

PubMed

Gao, Xingwen; Cai, Xuejian; Yan, Kai; Song, Baoan; Gao, Lili; Chen, Zhuo

2007-12-27

A simple and general method has been developed for the synthesis of various4(3H)-quinazolinone derivatives by the treatment of the appropriate 3-amino-2-aryl-4(3H)-quinazolinone with a substituted benzaldehyde in ethanol. The structures of the compoundswere characterized by elemental analysis, IR, (1)H-NMR and (13)C-NMR spectra. The title 2-aryl- or 2-methyl-3-(substituted-benzalamino)-4(3H)-quinazolinone compounds III-1~III-31 were found to possess moderate to good antiviral activity. Semi-quantitative PCR andReal Time PCR assays were used to ascertain the target of action of compound III-31against TMV. The studies suggest that III-31 possesses antiviral activity due to inductionof up-regulation of PR-1a and PR-5, thereby inhibiting virus proliferation and movementby enhancement of the activity of some defensive enzyme.

Seeing High Velocity Clouds and Turbulent Mixing Layers in the Ultraviolet: Predictions from Hydrodynamic Simulations

NASA Astrophysics Data System (ADS)

Shelton, Robin L.

2018-06-01

High velocity clouds (HVCs) and turbulent mixing layers (TMLs) emit light across a wide range of wavelengths. In order to aid in the detection of their ultraviolet emission, we predict the UV emission line intensities emitted by C II, C III, C IV, N II, N III, N IV, N V, O III, O IV, O V, O VI, Si II, Si III, and Si IV in a variety of simulated HVCs and TMLs. These predictions are based on detailed hydrodynamic simulations made with the FLASH code and employing non-equilibrium ionization calculations for carbon, nitrogen, oxygen, and silicon. The results are compared with FUSE and SPEAR/FIMS observations and with predictions from other models of hot/cool interfaces. We also present methods for scaling the results so that they can be applied to more or less dense environments.

The influence of IQ stratification on WAIS-III/WMS-III FSIQ-general memory index discrepancy base-rates in the standardization sample.

PubMed

Hawkins, K A; Tulsky, D S

2001-11-01

Since memory performance expectations may be IQ-based, unidirectional base rate data for IQ-Memory Score discrepancies are provided in the WAIS-III/WMS-III Technical Manual. The utility of these data partially rests on the assumption that discrepancy base rates do not vary across ability levels. FSIQ stratified base rate data generated from the standardization sample, however, demonstrate substantial variability across the IQ spectrum. A superiority of memory score over FSIQ is typical at lower IQ levels, whereas the converse is true at higher IQ levels. These data indicate that the use of IQ-memory score unstratified "simple difference" tables could lead to erroneous conclusions for clients with low or high IQ. IQ stratified standardization base rate data are provided as a complement to the "predicted difference" method detailed in the Technical Manual.

Modification and benchmarking of SKYSHINE-III for use with ISFSI cask arrays

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

Hertel, N.E.; Napolitano, D.G.

1997-12-01

Dry cask storage arrays are becoming more and more common at nuclear power plants in the United States. Title 10 of the Code of Federal Regulations, Part 72, limits doses at the controlled area boundary of these independent spent-fuel storage installations (ISFSI) to 0.25 mSv (25 mrem)/yr. The minimum controlled area boundaries of such a facility are determined by cask array dose calculations, which include direct radiation and radiation scattered by the atmosphere, also known as skyshine. NAC International (NAC) uses SKYSHINE-III to calculate the gamma-ray and neutron dose rates as a function of distance from ISFSI arrays. In thismore » paper, we present modifications to the SKYSHINE-III that more explicitly model cask arrays. In addition, we have benchmarked the radiation transport methods used in SKYSHINE-III against {sup 60}Co gamma-ray experiments and MCNP neutron calculations.« less

Development of a rapid and sensitive method for the determination of aluminum by reverse-phase high-performance liquid chromatography using a fluorescence detector.

PubMed

Heena; Kumar, Rajesh; Rani, Susheela; Malik, Ashok Kumar

2015-01-01

This study represents a new analytical high-performance liquid chromatography-fluorescence detector method for the determination of Al(III) as Al(III) complex with 8-hydroxyquinoline-5-sulfonic acid in a tap water sample and a coke sample. A micellar liquid chromatographic method is proposed for the determination of aluminum metal in the presence of cetyltrimethylammonium bromide, a cationic surfactant (0.05 M) used for the solubilization of the aluminum complex. The influence of pH and ligand concentration on the formation of the complex was studied by adding a small amount of 0.1 M sodium hydroxide. The metal chelate was detected at λEx 410 nm and λEm 510 nm. This method eliminates the need for addition of reagent or organic modifier to the mobile phase. The complex was analyzed using an Ascentis Express C18 column and a mobile phase consisting of acetonitrile, methanol and water (55 : 30 : 15). Under the optimized conditions, the linear range was 1-200 µg L(-1) and the limit of detection was 0.05 µg L(-1). The method showed a good detector response over the range of interest and was successfully applied for the determination of trace Al(III) in canned coke and water samples containing excess of Mg(II), Ca(II) and other matrices. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Efficiently Visible-Light Driven Photoelectrocatalytic Oxidation of As(III) at Low Positive Biasing Using Pt/TiO2 Nanotube Electrode

NASA Astrophysics Data System (ADS)

Qin, Yanyan; Li, Yilian; Tian, Zhen; Wu, Yangling; Cui, Yanping

2016-01-01

A constant current deposition method was selected to load highly dispersed Pt nanoparticles on TiO2 nanotubes in this paper, to extend the excited spectrum range of TiO2-based photocatalysts to visible light. The morphology, elemental composition, and light absorption capability of as-obtained Pt/TiO2 nanotubes electrodes were characterized by FE-SEM, energy dispersive spectrometer (EDS), X-ray photoelectron spectrometer (XPS), and UV-vis spectrometer. The photocatalytic and photoelectrocatalytic oxidation of As(III) using a Pt/TiO2 nanotube arrays electrode under visible light ( λ > 420 nm) irradiation were investigated in a divided anode/cathode electrolytic tank. Compared with pure TiO2 which had no As(III) oxidation capacity under visible light, Pt/TiO2 nanotubes exhibited excellent visible-light photocatalytic performance toward As(III), even at dark condition. In anodic cell, As(III) could be oxidized with high efficiency by photoelectrochemical process with only 1.2 V positive biasing. Experimental results showed that photoelectrocatalytic oxidation process of As(III) could be well described by pseudo-first-order kinetic model. Rate constants depended on initial concentration of As(III), applied bias potential and solution pH. At the same time, it was interesting to find that in cathode cell, As(III) was also continuously oxidized to As(V). Furthermore, high-arsenic groundwater sample (25 m underground) with 0.32 mg/L As(III) and 0.35 mg/L As(V), which was collected from Daying Village, Datong basin, Northern China, could totally transform to As(V) after 200 min under visible light in this system.

Study of uranium oxidation states in geological material.

PubMed

Pidchenko, I; Salminen-Paatero, S; Rothe, J; Suksi, J

2013-10-01

A wet chemical method to determine uranium (U) oxidation states in geological material has been developed and tested. The problem faced in oxidation state determinations with wet chemical methods is that U redox state may change when extracted from the sample material, thereby leading to erroneous results. In order to quantify and monitor U redox behavior during the acidic extraction in the procedure, an analysis of added isotopic redox tracers, (236)U(VI) and (232)U(IV), and of variations in natural uranium isotope ratio ((234)U/(238)U) of indigenous U(IV) and U(VI) fractions was performed. Two sample materials with varying redox activity, U bearing rock and U-rich clayey lignite sediment, were used for the tests. The Fe(II)/Fe(III) redox-pair of the mineral phases was postulated as a potentially disturbing redox agent. The impact of Fe(III) on U was studied by reducing Fe(III) with ascorbic acid, which was added to the extraction solution. We observed that ascorbic acid protected most of the U from oxidation. The measured (234)U/(238)U ratio in U(IV) and U(VI) fractions in the sediment samples provided a unique tool to quantify U oxidation caused by Fe(III). Annealing (sample heating) to temperatures above 500 °C was supposed to heal ionizing radiation induced defects in the material that can disturb U redox state during extraction. Good agreement between two independent methods was obtained for DL-1a material: an average 38% of U(IV) determined by redox tracer corrected wet chemistry and 45% for XANES. Copyright © 2013 Elsevier Ltd. All rights reserved.

Quality monitoring methods of initial and terminal manufacture of LiFePO4 based lithium ion batteries by capillary electrophoresis.

PubMed

Xie, Xia; Yang, Yang; Zhou, Henghui; Li, Meixian; Zhu, Zhiwei

2018-03-01

Magnetic impurities of lithium ion battery degrade both the capacity and cycling rates, even jeopardize the safety of the battery. During the material manufacture of LiFePO 4 , two opposite and extreme cases (trace impurity Fe(II) with high content of Fe(III) background in FePO 4 of initial end and trace Fe(III) with high content of Fe(II) background in LiFePO 4 of terminal end) can result in the generation of magnetic impurities. Accurate determination of impurities and precise evaluation of raw material or product are necessary to ensure reliability, efficiency and economy in lithium ion battery manufacture. Herein, two kinds of rapid, simple, and sensitive capillary electrophoresis (CE) methods are proposed for quality monitoring of initial and terminal manufacture of LiFePO 4 based lithium ion batteries. The key to success includes the smart use of three common agents 1,10-phenanthroline (phen), EDTA and cetyltrimethyl ammonium bromide (CTAB) in sample solution or background electrolyte (BGE), as well as sample stacking technique of CE feature. Owing to the combination of field-enhanced sample injection (FESI) technique with high stacking efficiency, detection limits of 2.5nM for Fe(II) and 0.1μM for Fe(III) were obtained corresponding to high content of Fe(III) and Fe(II), respectively. The good recoveries and reliability demonstrate that the developed methods are accurate approaches for quality monitoring of LiFePO 4 manufacture. Copyright © 2017 Elsevier B.V. All rights reserved.

Utility of solid phase extraction for spectrophotometric determination of gold in water, jewel and ore samples.

PubMed

Amin, Alaa S

2010-12-01

A highly sensitive, selective and rapid method for the determination μg L(-1) level of Au(III) based on the rapid reaction of Au(III) with 2,3-dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline (DCHNAQ) and the solid phase extraction of the colored complex with a reversed phase polymer-based C18 cartridge have been developed. The DCHNAQ reacted with Au(III) to form a violet complex of a molar ratio 3:1 [DCHNAQ to Au(III)] in the presence of 5.0 M of phosphoric acid solution and Triton X-100 medium. This complex was enriched by the solid phase extraction with a polymer-based C18 cartridge. The enrichment factor of 100 was achieved. The molar absorptivity of the complex is 2.73×10(5) l mol(-1) cm(-1) at 633 nm in the measured solution. The system obeys Beer's law in the range of 0.02-1.30 μg ml(-1), whereas the optimum concentration ranges obtained from Ringbom plot was 0.08-1.24 μg ml(-1). The relative standard deviation for ten replicates sample of 0.6 μg ml(-1) level is 1.28%. The detection and quantification limits, are 6.1 and 19.5 ng ml(-1) in the original sample. This method was applied to the determination of gold in water, jewel and ore samples with good results comparing to the GFAAS method. Copyright © 2010 Elsevier B.V. All rights reserved.

75 FR 13745 - Office of Innovation and Improvement Overview Information; Ready To Teach Program-General...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-23

... on rigorous, scientifically based research methods to assess the effectiveness of a particular... and programs; and (B) Includes research that-- (i) Employs systematic, empirical methods that draw on... hypotheses and justify the general conclusions drawn; (iii) Relies on measurements or observational methods...

14 CFR 135.340 - Initial and transition training and checking: Flight instructors (aircraft), flight instructors...

Code of Federal Regulations, 2010 CFR

2010-01-01

... principles of the teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor... certificate holder's policies and procedures. (3) The applicable methods, procedures, and techniques for... approved methods, procedures, and limitations for performing the required normal, abnormal, and emergency...

14 CFR 121.414 - Initial and transition training and checking requirements: flight instructors (airplane), flight...

Code of Federal Regulations, 2014 CFR

2014-01-01

...-learning process; (ii) Teaching methods and procedures; and (iii) The instructor-student relationship. (d... procedures. (3) The appropriate methods, procedures, and techniques for conducting flight instruction. (4... corrective action in the case of unsatisfactory training progress. (6) The approved methods, procedures, and...

14 CFR 135.340 - Initial and transition training and checking: Flight instructors (aircraft), flight instructors...

Code of Federal Regulations, 2014 CFR

2014-01-01

... principles of the teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor... certificate holder's policies and procedures. (3) The applicable methods, procedures, and techniques for... approved methods, procedures, and limitations for performing the required normal, abnormal, and emergency...

14 CFR 135.340 - Initial and transition training and checking: Flight instructors (aircraft), flight instructors...

Code of Federal Regulations, 2012 CFR

2012-01-01

... principles of the teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor... certificate holder's policies and procedures. (3) The applicable methods, procedures, and techniques for... approved methods, procedures, and limitations for performing the required normal, abnormal, and emergency...

14 CFR 135.340 - Initial and transition training and checking: Flight instructors (aircraft), flight instructors...

Code of Federal Regulations, 2013 CFR

2013-01-01

... principles of the teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor... certificate holder's policies and procedures. (3) The applicable methods, procedures, and techniques for... approved methods, procedures, and limitations for performing the required normal, abnormal, and emergency...

14 CFR 135.340 - Initial and transition training and checking: Flight instructors (aircraft), flight instructors...

Code of Federal Regulations, 2011 CFR

2011-01-01

... principles of the teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor... certificate holder's policies and procedures. (3) The applicable methods, procedures, and techniques for... approved methods, procedures, and limitations for performing the required normal, abnormal, and emergency...