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1

The volume change for the dissociation of telluric acid  

Microsoft Academic Search

The hydrolysis constants of telluric acid were determined by potentiometric titrations at 25°C andI=1.0 mol kg-1 NaClO4. Using these results the partial molar volume change according to the dissociation reaction Te(OH)6(aq) ? TeO(OH)5(aq)-+H(aq)+ was measured densitymetrically.

Harald Marhold; Wolfgang Sagmüller; Heinz Gamsjäger

1988-01-01

2

Structure and IR spectra of the solid complex of bis (betaine)—telluric acid  

NASA Astrophysics Data System (ADS)

Crystals of bis (betaine)-telluric acid of the formula [(CH 3) 3NCH 2CO 2] 2· Te(OH) 6 are triclinic, space group P-1, with a = 7.164(5), b = 8.325(5), c = 10.035(6) Å, ? = 108.58(5), ? = 123.82(4), ? = 96.02(5)° and Z=1. The crystal structure, solved by the heavy atom method, has been refined to R = 0.0215 for 3887 non-zero reflections. The betaine molecules are linked to telluric acid molecules by three kinds of O⋯O hydrogen bonds of length 2.561(4) Å, 2.760(3) Å and 2.800 (3) Å, respectively. Both species are joined into infinite chains along the a direction. Powder FT-IR spectra of the title crystal and its deuterated analogue at differential temperatures have been taken. The broad band at 3116 cm -1 is assigned to the stretching vibrations of the long hydrogen bonds. The two bands at 2671 and 2443 cm -1 are attributed to the stretching vibration of the short hydrogen bond. The internal vibrations of both the tellurate ions and betaine molecules are discussed. An assignment of the bands arising from these vibrations is proposed.

Ilczyszyn, M. M.; Lis, T.; Baran, J.; Ratajczak, H.

1992-02-01

3

Interstellar spectral features and telluric absorption lines  

NASA Astrophysics Data System (ADS)

In good quality spectra of stars the weak interstellar absorption lines may be substantially contaminated by telluric lines. Many telluric lines may also simulate interstellar absorptions. To avoid undesirable telluric effects during searches for interstellar absorptions, especially for diffuse interstellar bands (DIBs), we looked for all accessible catalogued telluric absorption lines in our spectra which contain DIBs. We investigated the echelle spectra of two stars, oPer and ?Tau, to revise the list of DIBs in oPer direction known from literature. We found that many telluric features simulate interstellar absorptions. We present the example parts of spectra to visualize this problem.

Ku?micz, A.; Wszo?ek, B.

2012-03-01

4

Structural evolution in iron tellurates  

NASA Astrophysics Data System (ADS)

Three new members within the iron tellurate family have been synthesized and characterized by single-crystal diffraction. Fe2Te3O9 is orthorhombic, a=7.80240(10) Å, b=17.7501(3) Å, c=5.28050(10) Å, Z=4, space group Pnma, final agreement factors R1=0.0261(wR2=0.0688) for 1271 independent reflections. Fe3Te4O12 is monoclinic, a=9.1312(2) Å, b=7.3554(2) Å, c=15.7379(3) Å, ?=107.950(10)?, Z=4, space group P21/c, final agreement factors R1=0.0380(wR2=0.0281) for 3302 independent reflections. FeTe6O13 is trigonal, a=b=10.16630(10) Å, c=18.9330(3) Å, Z=6, space group R3¯m, final agreement factors R1=0.0309(wR2=0.0641) for 1264 independent reflections. Together with the four already known members of the family, Fe2TeO5, Fe2TeO6, and Fe2Te3O9 (a dimorphic variant of the afore-mentioned structure with the same chemical formula), and Fe2Te4O11, the iron tellurates now span from relatively Fe-rich and Te-poor to relatively Fe-poor to Te-rich compounds. The structural diversity within Fe-Te-O system is discussed in terms of the lone-pair stereochemistry of the Te anion and the cross-over from Fe to mixed-valence Fe/Fe and Fe coordination polyhedra compounds.

van der Lee, A.; Astier, R.

2007-04-01

5

Thermodynamic characterization of lanthanum tellurate  

NASA Astrophysics Data System (ADS)

The standard Gibbs energy of formation of lanthanum tellurate, La 2TeO 6 was derived from its vapour pressure measurements in the temperature range 1420-1520 K employing TG based transpiration method. The temperature dependence of vapour pressure of TeO 2 vapour over the mixture La 2TeO 6 (s) + La 2O 3 (s) generated by the incongruent vapourisation reaction, LaTeO (s)?Lao (s)+TeO (g)+1/2O (g) could be represented as: log p (Pa) = [18.47-27127/ T (K)] ± 0.03 (1420-1520 K). Enthalpy increments on La 2TeO 6 were determined by using inverse drop calorimetry in the temperature range 583-1287 K and the thermodynamic functions, namely, heat capacity, entropy and Gibbs energy functions were derived. The mean value of -2381.3 ± 2.0 kJ mol -1 was obtained for ? fH298? (La 2TeO 6) by combining the value of ? fG? (La 2TeO 6) derived from vapour pressure data and the free energy functions of La 2TeO 6 derived from the drop calorimetry data.

Pankajavalli, R.; Jain, Ashish; Babu, R.; Ananthasivan, K.; Anthonysamy, S.; Ganesan, V.

2010-02-01

6

Molecfit: A Package for Telluric Absorption Correction  

NASA Astrophysics Data System (ADS)

Correcting for the sky signature usually requires supplementary data which are very expensive in terms of telescope time. In addition, the scheduling flexibility is restricted as these data have to be taken usually directly before/after the science observations due to the high variability of the telluric absorption which depends on the state and the chemical composition of the atmosphere at the time of observations. Therefore, a tool for sky correction, which does not require this supplementary calibration data, saves a significant amount of valuable telescope time and increases its efficiency. We developed a software package aimed at performing telluric feature corrections on the basis of synthetic absorption spectra.

Kausch, W.; Noll, S.; Smette, A.; Kimeswenger, S.; Horst, H.; Sana, H.; Jones, A. M.; Barden, M.; Szyszka, C.; Vinther, J.

2014-05-01

7

Genetic evidence for a molybdopterin-containing tellurate reductase.  

PubMed

The genetic identity and cofactor composition of the bacterial tellurate reductase are currently unknown. In this study, we examined the requirement of molybdopterin biosynthesis and molybdate transporter genes for tellurate reduction in Escherichia coli K-12. The results show that mutants deleted of the moaA, moaB, moaE, or mog gene in the molybdopterin biosynthesis pathway lost the ability to reduce tellurate. Deletion of the modB or modC gene in the molybdate transport pathway also resulted in complete loss of tellurate reduction activity. Genetic complementation by the wild-type sequences restored tellurate reduction activity in the mutant strains. These findings provide genetic evidence that tellurate reduction in E. coli involves a molybdoenzyme. PMID:23475618

Theisen, Joanne; Zylstra, Gerben J; Yee, Nathan

2013-05-01

8

Genetic Evidence for a Molybdopterin-Containing Tellurate Reductase  

PubMed Central

The genetic identity and cofactor composition of the bacterial tellurate reductase are currently unknown. In this study, we examined the requirement of molybdopterin biosynthesis and molybdate transporter genes for tellurate reduction in Escherichia coli K-12. The results show that mutants deleted of the moaA, moaB, moaE, or mog gene in the molybdopterin biosynthesis pathway lost the ability to reduce tellurate. Deletion of the modB or modC gene in the molybdate transport pathway also resulted in complete loss of tellurate reduction activity. Genetic complementation by the wild-type sequences restored tellurate reduction activity in the mutant strains. These findings provide genetic evidence that tellurate reduction in E. coli involves a molybdoenzyme.

Theisen, Joanne; Zylstra, Gerben J.

2013-01-01

9

TelFit: Fitting the telluric absorption spectrum  

NASA Astrophysics Data System (ADS)

TelFit calculates the best-fit telluric absorption spectrum in high-resolution optical and near-IR spectra. The best-fit model can then be divided out to remove the telluric contamination. Written in Python, TelFit is essentially a wrapper to LBLRTM, the Line-By-Line Radiative Transfer Model, and simplifies the process of generating a telluric model.

Gullikson, Kevin

2014-05-01

10

Photoinduced tautomeric transformations of xanthurenic acid.  

PubMed

The properties of xanthurenic acid (XAN) in ground and photoexcited states have been studied using steady-state and time-resolved optical methods as well as quantum chemistry calculations. In neutral aqueous solution and in alcohols, XAN is present in a single tautomeric form (keto form), whereas in aprotic solvents and probably in basic aqueous solutions, more than one tautomeric form is present. UV irradiation of aqueous and alcoholic solutions of XAN results in a very rapid solvent-assisted tautomerization to the enol form, the later undergoes solvent-assisted transformation back to the keto form. The photolysis of XAN in aprotic solvents gives rise to the formation of numerous intermediate forms of XAN in both triplet and ground states. Under intense laser irradiation, XAN undergoes biphotonic ionization, the precursor for ionization being the excited singlet state. PMID:20617247

Yanshole, Vadim V; Sherin, Peter S; Gritsan, Nina P; Snytnikova, Olga A; Mamatyuk, Victor I; Grilj, Jakob; Vauthey, Eric; Sagdeev, Renad Z; Tsentalovich, Yuri P

2010-08-28

11

Vibrational spectra of cesium tellurate phosphate  

NASA Astrophysics Data System (ADS)

The infrared and Raman spectra of cesium tellurate phosphate (Te(OH) 6·Cs 2HPO 4), a compound containing two anions, are recorded and analysed. It has been found that the two anions Te(OH) 6 and HPO 4 coexist in the crystal almost independently without affecting each other. The hydrogen atom is loosely bonded to the oxygen atom of the phosphate ion and hence the phosphate ion exists as distorted PO 3-4 tetrahedron rather than HPO 2-4 ion.

Viswanathan, K.; Nayar, V. U.; Aruldhas, G.

1986-11-01

12

Temporal variability of the telluric sodium layer  

NASA Astrophysics Data System (ADS)

The temporal variability of the telluric sodium layer is investigated by analyzing 28 nights of data obtained with the Colorado State University LIDAR experiment. The mean height power spectrum of the sodium layer was found to be well fitted by a power law over the observed range of frequencies, 10 ?Hz to 4 mHz. The best-fitting power law was found be be 10???, with ?=-1.79±0.02 and ?=1.12±0.40. Applications to wavefront sensing require knowledge of the behavior of the sodium layer at kilohertz frequencies. Direct measurements at these frequencies do not exist. Extrapolation from low-frequency behavior to high frequencies suggests that this variability may be a significant source of error for laser guide star adaptive optics in large-aperture telescopes.

Davis, D. Saul; Hickson, Paul; Herriot, Glen; She, Chiao-Yao

2006-11-01

13

Transformation of thiophenic compounds over acidic zeolites  

Microsoft Academic Search

The transformation of thiophenic compounds (2-methylthiophene; 3-methylthiophene; 2,3-dimethylthiophene; 2,5-dimethylthiophene; 2-methylbenzothiophene; 3-methylbenzothiophene) was carried out over HY zeolite at 350°C under atmospheric pressure in a fixed bed reactor. The transformation of some of them was also carried out over H?, HZSM5 and H-mordenite (HMOR). In the presence of HY, all the reactants underwent both isomerization and disproportionation in various proportions depending

T. Boita; M. Moreau; F. Richard; G. Pérot

2006-01-01

14

MICROBIAL TRANSFORMATION OF ESTERS OF CHLORINATED CARBOXYLIC ACIDS  

EPA Science Inventory

Two groups of compounds were selected for microbial transformation studies. In the first group were carboxylic acid esters having a fixed aromatic moiety and an increasing length of the alkyl component. Ethyl esters of chlorine-substituted carboxylic acids were in the second grou...

15

EMT - Empirical-mode-decomposition-based Magneto-Telluric Processing  

NASA Astrophysics Data System (ADS)

We present a new Magneto-Telluric (MT) data processing scheme based on an emerging non linear, non stationary time series analysis tool, called the Empirical Mode Decomposition (EMD) or Hilbert-Huang Transform (HHT), to transform data into a non-stationary frequency domain and a robust principal component regression to estimate the most likely MT transfer functions from the data with the 2-? confidence intervals computed by a bootstrap algorithm. Optionally, data quality can be controlled by a physical coherence and a signal power filter. MT sources are assumed to be quasi stationary and therefore a (windowed) Fourier Transform is often applied to transform the time series into the frequency domain in which Transfer Functions (TF) are defined between the electromagnetic field components. This assumption can break down in the presence of noise or when the sources are non stationary, and then TF estimates can become unreliable when obtained through a stationary transform like the Fourier transform. Our TF estimation scheme naturally deals with non stationarity without introducing artifacts and, therefore, potentially can distinguish quasi-stationary sources and non-stationary noise. In contrast to previous works on using HHT for MT processing, we argue the necessity of a multivariate EMD to model the MT problem physically correctly and highlight the resulting possibility to use instantaneous parameters as independent and identically distributed variables. Furthermore, we define a homogenization between data channels of frequency discrepancies due to non stationarity and noise. The TF estimation in the frequency domain bases on a robust principal component analysis in order to find two source polarizations. These two principal components are used as predictor to regress robustly the data channels within a bootstrap algorithm to estimate the Earth's Transfer function with 2-? confidence interval supplied by the measured data.The scheme can be used with and without aid by any number of remote reference stations. The performance of this scheme will be demonstrated on MT data and compared with BIRRP, a widely used MT processing software by Alan Chave.

Neukirch, M.; Garcia, X.

2012-04-01

16

Transformations of tributyl phosphate in contact with acidic aqueous solutions  

SciTech Connect

Investigation of the transformations of tributyl phosphate in contact with fluoridesulfuric acid solutions be means of method /sup 19/F and /sup 31/P NMR spectroscopy and potentiometric titration shows that in the course of time it undergoes processes of hydrolysis and fluorination. In the extracts acid butyl phosphates and phosphoric acid together with products of their fluorination were found. The extent of the breakdown of tributyl phosphate depends on the time and the composition of the aqueous solutions.

Nikolaev, A.I.; Ignatov, M.E.; Shevyreva, E.V.; Zalkind, L.M.; Il'in, E.G.; Buslaev, Y.A.

1986-11-20

17

Chemical transformations of methane in trifluoroacetic acid  

NASA Astrophysics Data System (ADS)

The reaction of methane conversion in anhydrous trifluoroacetic acid (TFA) is shown to take place at room temperature and atmospheric pressure and to result in the formation of a resinous product. Signals of ions with molecular weights of 684 and 700 are observed in MALDI-TOF spectra of the dry residue of methane conversion products.

Vishnetskaya, M. V.; Svichkarev, O. M.; Budynina, E. M.; Mel'nikov, M. Ya.

2013-12-01

18

Telluric and magnetotelluric study of the Ferrara High (northern Italy)  

NASA Astrophysics Data System (ADS)

A telluric survey and several magnetotelluric (MT) soundings have been carried out across the Ferrara High (northern Italy), in a geothermal area previously explored in detail during a search for oil. The aim was to compare telluric, MT and gravimetric data with a structural model derived from a seismic investigation in a region of fairly well-known geology. The comparison between observed and predicted telluric pseudo-sections reveals a much better agreement than expected, especially since the gravimetric field data clearly show that the structure is effectively 3-D whereas the comparison was restricted to a single profile with 2-D interpretations. The 3-D character seems to appear most clearly in the telluric parameters at periods > 10 s. In the search for a 2-D interpretation of the telluric and MT data, an attempt was made to reduce the family of possible models by imposing external constraints. It was gratifying to find that the best fit with the seismic 2-D model was obtained when a uniform resistivity was required for each of the separate formations revealed by the seismic sounding.

Iliceto, V.; Malaguti, R.; Santarato, G.; Schnegg, P.-A.; Fischer, G.

1989-03-01

19

Unique roles of acidic amino acids in phase transformation of calcium phosphates.  

PubMed

Although phase transformation is suggested as a key step in biomineralization, the chemical scenario about how organic molecules mediate inorganic phase transformations is still unclear. The inhibitory effect of amino acids on hydroxyapatite (HAP, the main inorganic component of biological hard tissues such as bone and enamel) formation was concluded by the previous biomimetic modeling based upon direct solution crystallization. Here we demonstrate that acidic amino acids, Asp and Glu, could promote HAP crystallization from its precursor crystal, brushite (DCPD). However, such a promotion effect could not be observed when the nonacidic amino acids were applied in the transformation-based HAP formation. We found that the specific modification of acidic amino acid on crystal-solution interfaces played a key role in the phase transition. The distinct properties between DCPD and HAP in the solution resulted in an interfacial energy barrier to suppress the spontaneous formation of HAP phase on DCPD phase. Different from the other amino acids, the carboxylate-rich amino acids, Asp and Glu, could modify the interfacial characteristics of these two calcium phosphate crystals to make them similar to each other. The experiments confirmed that the involvement of Asp or Glu reduced the interfacial energy barrier between DCPD and HAP, leading to a trigger effect on the phase transformation. An in-depth understanding about the unique roles of acidic amino acids may contribute to understanding phase transformation controls druing biomineralization. PMID:21190387

Chu, Xiaobin; Jiang, Wenge; Zhang, Zhisen; Yan, Yang; Pan, Haihua; Xu, Xurong; Tang, Ruikang

2011-02-10

20

Transforming Growth Factors: Isolation of Polypeptides from Virally and Chemically Transformed Cells by Acid \\/ Ethanol Extraction  

Microsoft Academic Search

Polypeptides characterized by their ability to confer a transformed phenotype on an untransformed indicator cell have been isolated directly from tumor cells growing both in culture and in the animal, by using an acid \\/ ethanol extraction procedure. Assay of these polypeptides is based on their ability to induce normal rat kidney fibroblasts to form colonies in soft agar. Peptides

Anita B. Roberts; Lois C. Lamb; Dianne L. Newton; Michael B. Sporn; Joseph E. de Larco; George J. Todaro

1980-01-01

21

Magnetic properties of some rare earth tellurate garnets  

NASA Astrophysics Data System (ADS)

The magnetic properties of the lanthanide tellurate garnets Ln3Te2Li3O12 for Ln=Pr, Nd, Gd Er, and Yb are found to exhibit similarities in many cases to the related aluminum or gallium garnet compounds. Magnetic exchange is also roughly comparable in magnitude, despite the systematic difference in exchange pathways.

Applegate, Ryan P.; Zong, Yuhua; Corruccini, L. R.

2007-09-01

22

Telluric currents: A meeting of theory and observation  

SciTech Connect

Pipe-to-soil (P/S) potential variations resulting from telluric currents have been observed on pipelines in many locations. However, it has never teen clear which parts of a pipeline will experience the worst effects. Two studies were conducted to answer this question. Distributed-source transmission line (DSTL) theory was applied to the problem of modeling geomagnetic induction in pipelines. This theory predicted that the largest P/S potential variations would occur at the ends of the pipeline. The theory also predicted that large P/S potential variations, of opposite sign, should occur on either side of an insulating flange. Independently, an observation program was conducted to determine the change in telluric current P/S potential variations and to design counteractive measures along a pipeline in northern Canada. Observations showed that the amplitude of P/S potential fluctuations had maxima at the northern and southern ends of the pipeline. A further set of recordings around an insulating flange showed large P/S potential variations, of opposite sign, on either side of the flange. Agreement between the observations and theoretical predictions was remarkable. While the observations confirmed the theory, the theory explains how P/S potential variations are produced by telluric currents and provides the basis for design of cathodic protection systems for pipelines that can counteract any adverse telluric effects.

Boteler, D.H. [Geological Survey of Canada, Ottawa, Ontario (Canada). Geomagnetic Lab.; Seager, W.H. [CORRPRO, Calgary, Alberta (Canada)

1998-09-01

23

Radial Velocities of Low-mass Stars Using Telluric Lines  

NASA Astrophysics Data System (ADS)

The search for companions to the lowest mass stars offers us an exciting pathway toward the detection of Earth-like planets. Low mass-stars are intrinsically small and cool, motivating the development of observational techniques optimized for the deep red (700 to 1000 nm) and infrared wavelengths where these stars are brightest. However, Earth's atmosphere absorbs strongly in these spectral regions, and telluric features due to O2, H2O, CH4, and CO2 dominate significant portions of ground-based spectra at red wavelengths. For the specific application of radial velocity (RV) measurements of low-mass stars, wavelengths where there is significant telluric absorption present a distinct advantage. The telluric lines provide a rich set of absorption features that can readily serve as a simultaneous absorption reference, yielding RV measurements of modest precision using existing instrumentation. We describe the theoretical expectations regarding the fundamental limits of telluric lines as a "zero velocity" wavelength reference and present results from detailed simulations of absorption by Earth's atmosphere as well as the impact of atmospheric variations on RV precision. We present preliminary results from a deep red optical survey of 100 late-M stars that relies on telluric water vapor as a simultaneous reference. We demonstrate that long-term stability of 10 m/s may be achievable using a typical echelle spectrograph, theoretical models of the composition of Earth's atmosphere, and some basic assumptions about the time variability of the atmosphere. This work has been supported by the National Science Foundation through an Astronomy and Astrophysics Postdoctoral Fellowship.

Blake, Cullen; Shaw, M.

2011-09-01

24

Diffuse reflectance Fourier transform infrared spectroscopy of oleic acid adsorption on silicic acid  

Microsoft Academic Search

Diffuse reflectance Fourier transform infrared spectroscopy was used to observe adsorption complexes of oleic acid and isopropanol\\u000a (IPA) on silicic acid in hexane. The spectra provide definite evidence of the molecular nature of the surface interaction.\\u000a In addition, the effect on oleic acid adsorption of modifying the solvent with IPA, which competes for adsorption sites and\\u000a modifies the solvent polarity,

C. Adhikari; A. Proctor; G. D. Blyholder

1994-01-01

25

Surface reactions of iron - enriched smectites: adsorption and transformation of hydroxy fatty acids and phenolic acids  

NASA Astrophysics Data System (ADS)

Iron-enriched smectites play an important role in adsorption and transformation of soil organic components. Soil organo-clay complexes, and in particular humin contain hydroxy fatty acids, which are derived from plant biopolymer cutin. Phenolic acids belong to another major group of organic acids detected in soil. They participate in various soil processes, and are of concern due to their allelopathic activity. We studied the reactivity of iron-enriched smectites (Fe(III)-montmorillonite and nontronite) toward both groups of acids. We used fatty acids- 9(10),16-dihydroxypalmitic acid (diHPA), isolated from curtin, and 9,10,16-trihydroxypalmitic acid (triHPA); the following phenolic acids were used: ferulic, p-coumaric, syringic, and vanillic. Adsorption of both groups of acids was measured. The FTIR spectra of fatty acid-mineral complexes indicated inner-sphere complexation of fatty acids with iron-enriched smectites (versus outer-sphere complexation with Ca(II)-montmorillonite). The LC-MS results demonstrated enhanced esterification of fatty acids on the iron-enriched smectite surfaces (as compared to Ca(II)-montmorillonite). This study suggests that fatty acids can be esterified on the iron-enriched smectite surfaces, which results in the formation of stable organo-mineral complexes. These complexes may serve as a model for the study of natural soil organo-clay complexes and humin. The reaction of phenolic acids with Fe(III)-montmorillonite demonstrated their oxidative transformation by the mineral surfaces, which was affected by molecular structure of acids. The following order of their transformation was obtained: ferulic >syringic >p-coumaric >vanillic. The LC-MS analysis demonstrated the presence of dimers, trimers, and tetramers of ferulic acid on the surface of Fe(III)-montmorillonite. Oxidation and transformation of ferulic acid were more intense on the surface of Fe(III)-montmorillonite as compared to Fe(III) in solution due to stronger complexation on the Fe(III)-motnomrillonite surface. Our study demonstrate the importance of iron-enriched minerals for the abiotic formation of humic materials and for the transformation of aromatic (phenolic) pollutants.

Polubesova, Tamara; Olshansky, Yaniv; Eldad, Shay; Chefetz, Benny

2014-05-01

26

Ultra-low temperature processing of barium tellurate dielectrics  

NASA Astrophysics Data System (ADS)

Ceramics, metals and polymers have unique electrical properties that are combined for electronic devices and systems. It necessitates lower processing temperatures for ceramics to be compatible with metal and polymer systems. In this thesis, the synthesis, crystal structure, and dielectric properties of barium tellurate are studied for temperatures between 500 and 900°C. Barium tellurate dielectric ceramics (BaTe4O9, BaTe 2O5, BaTe2O6, BaTeO3, BaTeO 4, and Ba2TeO5) are extensively investigated as new LTCC (Low-Temperature Cofired Ceramics) dielectric systems integrated with low resistivity metal electrodes such as silver and aluminum for microwave application. Studies on the phase formation and crystal structure through thermal analyses (Differential Scanning Calorimetry and Thermogravimetric Analysis, DSC-TGA) and X-ray diffraction phase analysis attest that barium tellurates are formed in the temperature range of 500 ˜ 900°C, through the sequential phase formations from Te-rich to Ba-rich phases. The oxygen coordination of the tellurium ion progresses from TeO4 to TeO6 via TeO 3+1 and TeO3 with increasing barium content as confirmed by structural analysis using infrared spectroscopy. High density barium tellurate ceramics are achieved at temperatures as low as 550°C, which provides the potential to be co-fired with low-melting aluminum metal electrodes in LTCC processing. Dielectric permittivity, loss, and temperature stability of barium tellurate dielectric ceramics were measured from 100 Hz to 13 GHz. Barium tellurate ceramics exhibit excellent microwave dielectric properties with intermediate dielectric permittivities and high quality factors (Q). The dielectric properties at microwave frequencies are epsilonr = 17.5, Qxf = 54700 GHz, TCf = -90 ppm/°C for BaTe4O9, epsilonr = 21, Qxf = 50300 GHz, TCf = -51 ppm/°C for BaTe2O6, epsilonr = 10, Qxf = 34000 GHz, TCf = -54 ppm/°C for BaTeO3, and epsilonr = 17, Qx f = 49600 GHz, TCf = -124 ppm/°C for Ba 2TeO5. Co-firing studies of barium tellurate ceramics with metal electrodes establish new LTCC systems for microwave devices. Chemical compatibility of barium tellurates with silver electrodes was achieved in the barium rich compositions. Ba2TeO5 was found to be covetable with silver electrodes at 850°C by adding CuO and B2O3 as fluxing agents. During the co-firing, a thin interfacial layer of AgTe is metastable according to the thermodynamic equilibrium between the Ba2TeO5-Ag/Ag 2O pseudo-binary system. A breakthrough LTCC technology with aluminum is based upon the ultra-low processing temperature and chemical compatibility of BaTe4O 9, which enables co-firing and fabrication of multilayer ceramic capacitors (MLCCs) with aluminum inner electrodes. The aluminum base metal electrode (BME) BaTe4O9 MLCCs provide good dielectric properties of epsilonr = 17.5, TCepsilon = 100 ppm/°C, and tan delta = 2.1 x 10-3 (Q ? 500) at 1 MHz, which are suitable for the class-1 MLCCs. Aluminum microstrip ring resonators on the BaTe4O9 substrates realized good electromagnetic performance of the new materials at microwave frequency exhibiting resonant frequency of 2.97 GHz and Q factor of 278.

Kwon, Do-Kyun

27

A Comparison of Telluric Current and Magnetic Field Observations in the Arctic Ocean  

Microsoft Academic Search

Simultaneous observations of the H and D components of the magnetic field and of two components of telluric current were made on Arctic drifting station Charlie during the winter of 1959-1960 and on station Arlis I in early 1961. The telluric current and mag- netometer data show a striking similarity. Spectral analysis showed the two types of data to have

Daniel W. Swift; Victor P. Hessler

1964-01-01

28

Estudios Sobre Equilibrios de Polianiones. Xiii. Polimerizacion de Los Teluratos en Nacl 1 M Y 25 Degrees (Studies Concerning the Equilibria of Polyanions. Xiii. Polymerization of Tellurates in One Molar Nacl Solution at 25 Degrees C).  

National Technical Information Service (NTIS)

The hydrolysis of telluric acid was studied in 1M NaCl ionic medium. The H(+) concentration was measured using a glass electrode. B, the total tellurium concentration and Z, the number of H(+) split off per tellurium atom, were varied as follows: (0.005 M...

F. Brito

1966-01-01

29

Plants having modified response to ethylene by transformation with an ETR nucleic acid  

DOEpatents

The invention includes transformed plants having at least one cell transformed with a modified ETR nucleic acid. Such plants have a phenotype characterized by a decrease in the response of at least one transformed plant cell to ethylene as compared to a plant not containing the transformed plant cell. Tissue and/or temporal specificity for expression of the modified ETR nucleic acid is controlled by selecting appropriate expression regulation sequences to target the location and/or time of expression of the transformed nucleic acid. The plants are made by transforming at least one plant cell with an appropriate modified ETR nucleic acid, regenerating plants from one or more of the transformed plant cells and selecting at least one plant having the desired phenotype.

Meyerowitz, Elliott M. (Pasadena, CA); Chang, Caren (Pasadena, CA); Bleecker, Anthony B. (Madison, WI)

2001-01-01

30

Luminescence probing of structural transformations of yttrium acid oxalate trihydrate  

SciTech Connect

The structural transformations of yttrium acid oxalate trihydrate YH{sub 5}O{sub 2}(C{sub 2}O{sub 4}){sub 2}{center_dot}H{sub 2}O in the 77-350{degrees}K temperature range have been investigated with the aid of a luminescent probe in the form of an admixture of 5-15% Eu{sup 3+} ions replacing Y{sup 3+} ions. The vibronic luminescence (the {sup 5}D{sub 0}-{sup 7}F{sub 0-4} transitions) and excitation (the {sup 7}F{sub 0}-{sup 5}D{sub 0} transition) spectra of Eu{sup 3+}, as well as the IR absorption spectra, have ben studied. The temperature dependence of the crystal-field parameters has been spectra, have been studied. The temperature dependence of the crystal-field parameters has been examined. Deuteration has been employed to identify the bands of the librational and translations vibrations of the proton-containing groups. The anisotropic mobility of the proton-containing groups detected in the PMR spectra in the vicinity of 118 K as the samples are heated is manifested in the vibronic and IR spectra as smooth broadening and displacement of the bonds of the librational and translational vibrations of these groups to lower frequencies. The phase transition at 328 K is manifested in the luminescence spectra as an abrupt increase in the symmetry of the crystal field: the second-order axis is transformed into a fourth-order axis.

Tsaryuk, V.I.; Zolin, V.F.; Savchenko, V.D.; Yaroslavtsev, A.B. [Institute of Telecommunications and Electronics (Russian Federation)]|[M.V. Lomonosov Moscow State Univ. (Russian Federation)

1994-06-01

31

Review: Biocatalytic transformations of ferulic acid: An abundant aromatic natural product  

Microsoft Academic Search

In this review we examine the fascinating array of microbial and enzymatic transformations of ferulic acid. Ferulic acid is an extremely abundant, preformed phenolic aromatic chemical found widely in nature. Ferulic acid is viewed as a commodity scale, renewable chemical feedstock for biocatalytic conversion to other useful aromatic chemicals. Most attention is focused on bioconversions of ferulic acid itself. Topics

J P N Rosazza; Z Huang; L Dostal; T Volm; B Rousseau

1995-01-01

32

Transformation to Prototrophy and Polyglutamic Acid Synthesis in Bacillus Licheniformis.  

National Technical Information Service (NTIS)

Growth conditions necessary for transformation to prototrophy of 14 auxotrophs of Bacillus licheniformis were studied. The unexpected finding of different growth requirements by each auxotroph for the development of transformable cells is discussed. Under...

C. G. Leonard D. K. Mattheis M. J. Mattheis R. D. Housewright

1964-01-01

33

Dissimilatory reduction and transformation of ferrihydrite-humic acid coprecipitates.  

PubMed

Organic matter (OM) is present in most terrestrial environments and is often found coprecipitated with ferrihydrite (Fh). Sorption or coprecipitation of OM with Fe oxides has been proposed to be an important mechanism for long-term C preservation. However, little is known about the impact of coprecipitated OM on reductive dissolution and transformation of Fe(III) (oxyhydr)oxides. Thus, we study the effect of humic acid (HA) coprecipitation on Fh reduction and secondary mineral formation by the dissimilatory Fe(III)-reducing bacterium Shewanella putrefaciens strain CN32. Despite similar crystal structure for all coprecipitates investigated, resembling 2-line Fh, the presence of coprecipitated HA resulted in lower specific surface areas. In terms of reactivity, coprecipitated HA resulted in slower Fh bioreduction rates at low C/Fe ratios (i.e., C/Fe ? 0.8), while high C/Fe ratios (i.e., C/Fe ? 1.8) enhanced the extent of bioreduction compared to pure Fh. The coprecipitated HA also altered the secondary Fe mineralization pathway by inhibiting goethite formation, reducing the amount of magnetite formation, and increasing the formation of a green rust-like phase. This study indicates that coprecipitated OM may influence the rates, pathway, and mineralogy of biogeochemical Fe cycling and anaerobic Fe respiration within soils. PMID:24219167

Shimizu, Masayuki; Zhou, Jihai; Schröder, Christian; Obst, Martin; Kappler, Andreas; Borch, Thomas

2013-12-01

34

Mass spectrometric study of vaporization of cesium tellurate and tellurite  

NASA Astrophysics Data System (ADS)

The process of vaporization of cesium tellurate and tellurite was studied by the Knudsen effusion method with a mass spectrometric analysis of the vapor composition. The thermal dissociation of Cs 2TeO 4 to Cs 2TeO 3 and the congruent vaporization of Cs 2TeO 3 were established. Thermodynamic functions for gaseous Cs 2TeO 3 have been calculated. The standard enthalpy of sublimation ?sH° (298.15) = 268.1 ± 13.0 kJmol-1 was determined by the 2nd and 3rd laws of thermodynamics. The enthalpy of formation ?sH° (298.15) = -725.1 ± 13.0 kJmol-1 for gaseous Cs 2TeO 3 and the enthalpy of atomization ?atH°(298.15) = 1841.3 ± 15.0 kJmol-1 have been computed.

Semenov, G. A.; Fokina, L. A.; Mouldagalieva, R. A.

1994-06-01

35

Characterization of p-CdTe obtained by CVTG tellurization of electrodeposited CdTe  

Microsoft Academic Search

CdTe thin films were electrodeposited from an ethylene-glycol-based bath by the galvanostatic method. As-deposited and tellurized films were characterized by structural, opto-electronic and photoelectrochemical methods. As-deposited films were powdery in nature and showed n-type conductivity due to the elemental nature of the film. The film stoichiometry was improved after tellurization of the film at 300°C by a new technique called

S. A Gamboa; P. J Sebastian; M. A Rivera

1998-01-01

36

A magneto-telluric deep crustal study in south-central Portugal  

Microsoft Academic Search

Summary A geothermal anomaly reported to exist in southern Portugal and with heat flow density values as high as 160 mW\\/m2 was studied by the magneto-telluric method. The results of the magneto-telluric survey indicate that the study area is divided into several high electrical resistivity, deep-rooted blocks separated by low electrical resistivity zones. These latter zones coincide with the main

A. Correia; F. W. Jones; G. K. Dawes; V. R. S. HtrrTON

1993-01-01

37

Étude électrochimique des systèmes binaires et ternaire engageant les éléments bismuth, antimoine et tellure  

NASA Astrophysics Data System (ADS)

Dans la présente étude, nous nous sommes intéressés à la recherche des meilleures conditions de synthèse du composé Bi0,5Sb1,5Te3, présentant des propriétés thermoélectriques optimales à température ambiante pour un composé de type p. Une étude voltampérométrique a donc été menée pour les binaires engageant ces trois éléments, c’est-à-dire Bi-Te et Sb-Te, ainsi que pour le ternaire Bi-Sb-Te. Les ions BiIII+, SbIII+ et TeIV+ ont été mis en solution dans l’électrolyte acide perchlorique HClO4 1M acide tartrique C4H6O6 0,1M, avec une concentration maximale en tellure de l’ordre de 10-2M. Les rapports envisagés entre les ions, choisis en fonction d’études antérieures, sont les suivants : Bi/Te=1 et Sb/Te=1 pour les binaires, et (Bi+Sb)/Te=1 et Sb/Bi=3 pour le ternaire. Des dépôts ont été réalisés à différents potentiels, de manière à identifier les pics obtenus sur les voltampérogrammes. Ces dépôts ont été caractérisés par diffraction des rayons X, et leur stoechiométrie a été obtenue par microsonde de Castaing.

del Frari, D.; Diliberto, S.; Boulanger, C.; Lecuire, J. M.

2004-12-01

38

Chemical transformations of CO2 in trifluoroacetic acid solutions  

NASA Astrophysics Data System (ADS)

It is established that a conversion reaction of carbon dioxide takes place at room temperature and atmospheric pressure in aqueous solutions of trifluoroacetic acid (TFA), which leads to the formation of oxalic acid and heavier polymerized products.

Vishnetskaya, M. V.; Ivanova, M. S.; Svichkarev, O. M.; Budynina, E. M.; Mel'nikov, M. Ya.

2013-05-01

39

Helix-coil transformation and titration curve of poly-L-glutamic acid  

Microsoft Academic Search

The titration curve of poly-L-glutamic acid was studied in connection with the helix-coil transformation. In aqueous solution the transformation has its origin in the ionization of the polar group COOH in the side chain. Conversely the ionization and the titration curve of this molecule are affected by the change of the electrostatic interaction produced by its transformation. It is shown

Akiyoshi Wada

1960-01-01

40

On the mechanisms of fatty acid transformations in membranes  

Microsoft Academic Search

Concentrations of albumin in excess of 1% in the incubation mixture inhibited the elongation of added fatty acids and their\\u000a incorporation into microsomal lipids whereas these reactions were not inhibited with endogenous microsomal membrane fatty\\u000a acids. The results of these and other studies support the idea that such reactions of membrane lipid fatty acids with membrane-bound\\u000a enzymes normally occur entirely

Minerva Gan-Elepano; Ernesto Aeberhard; James F. Mead

1981-01-01

41

Dinuclear manganese centers in the manganese-lead-tellurate glasses.  

PubMed

FTIR, UV-VIS and EPR spectra of manganese doped lead-tellurate glasses with composition xMnO·(100-x)[4TeO2·PbO2] where x=0, 1, 5, 10, 20, 30, 40mol% have been studied. The FTIR spectra show the formation of the Mn-O-Pb and Mn-O-Te bridging bonds by increasing of MnO concentration. The UV-VIS spectra show the Mn(+3) species exhibit pronounced absorption, which masks the Mn(+2) spin-forbidden absorption bands when Mn(+2) ions are in high concentrations in these glasses. The EPR spectra exhibit resonance signals characteristic of Mn(+2) ions. The resonance signal located at g?2 is due to Mn(+2) ions in an environment close to octahedral symmetry, whereas the resonance at g?4.3 and 3.3 are attributed to the rhombic surroundings of the Mn(+2) ions. The increase in the MnO content gives rise to absorption at g?2.4 and the paramagnetic ions are involved in dinuclear manganese centers. PMID:21498108

Rada, S; Dehelean, A; Culea, M; Culea, E

2011-07-01

42

Dinuclear manganese centers in the manganese-lead-tellurate glasses  

NASA Astrophysics Data System (ADS)

FTIR, UV-VIS and EPR spectra of manganese doped lead-tellurate glasses with composition xMnO·(100 - x)[4TeO 2·PbO 2] where x = 0, 1, 5, 10, 20, 30, 40 mol% have been studied. The FTIR spectra show the formation of the Mn-O-Pb and Mn-O-Te bridging bonds by increasing of MnO concentration. The UV-VIS spectra show the Mn +3 species exhibit pronounced absorption, which masks the Mn +2 spin-forbidden absorption bands when Mn +2 ions are in high concentrations in these glasses. The EPR spectra exhibit resonance signals characteristic of Mn +2 ions. The resonance signal located at g ? 2 is due to Mn +2 ions in an environment close to octahedral symmetry, whereas the resonance at g ? 4.3 and 3.3 are attributed to the rhombic surroundings of the Mn +2 ions. The increase in the MnO content gives rise to absorption at g ? 2.4 and the paramagnetic ions are involved in dinuclear manganese centers.

Rada, S.; Dehelean, A.; Culea, M.; Culea, E.

2011-07-01

43

Highly efficient transformation of levulinic acid into pyrrolidinones by iridium catalysed transfer hydrogenation.  

PubMed

Levulinic acid (LA) is transformed into pyrrolidinones via iridium-catalysed reductive amination using formic acid as the hydrogen source under aqueous conditions. The catalytic system is the most active and performs under the mildest conditions ever reported for the reductive amination of LA. PMID:23661188

Wei, Yawen; Wang, Chao; Jiang, Xue; Xue, Dong; Li, Jia; Xiao, Jianliang

2013-06-14

44

TMSCN/DBU-mediated facile redox transformation of ?,?-unsaturated aldehydes to carboxylic acid derivatives.  

PubMed

Redox transformation of an ?,?-unsaturated aldehyde to a carboxylic acid derivative by means of a combination of TMSCN and DBU was investigated. In addition to the wide use of the carboxylic acid derivatives provided by this reaction, temperature-dependent control of the kinetic or thermodynamic protonation pattern was found to selectively switch the stereochemistry of the acyl group in the product. PMID:24446807

Kaise, Hiromi; Shimokawa, Jun; Fukuyama, Tohru

2014-02-01

45

A final report on computed magneto-telluric curves for hypothetical models of crustal structure  

USGS Publications Warehouse

Several mathematical models were investigated to determine the capa-bilities of the magneto-telluric method for determining the resistivity structure of the earth's crust. The model parameters were based on the crust model proposed by Keller (1963). The mathematical technique used was developed by Cagniard (1953). The investigations indicate that a three-layer model approximation of the crust and mantle is the most detailed model warranted in inter-preting the information provided by the magneto-telluric method about the lower crust. Only the thickness of the lower crust can be determined, and not the resistivity.

Pritchard, J.I.

1965-01-01

46

Infrared spectroscopic and DFT investigations of the vanadate-tellurate glasses structures  

NASA Astrophysics Data System (ADS)

Vanadate-tellurate vitreous systems with composition (1 - x)TeO 2· xV 2O 5 where x = 0.3 and 0.4 have been prepared by the conventional melt-quench method. The structural aspects have been investigated using FTIR spectroscopy and the density functional theory (DFT) calculations. The present study provides the interesting information concerning devitrification behavior of the vanadate-tellurate vitreous system which occur Te 2V 2O 9 crystalline phase. The structure of the heat-treated glasses was found to consist mainly of rings containing [TeO 3], [TeO 4], [VO 4] and some [VO 5] structural units.

Rada, S.; Rada, M.; Culea, E.

2010-02-01

47

Mechanism of Inactivation of Haemophilus influenzae Transforming Deoxyribonucleic Acid by Sonic Radiation1  

PubMed Central

Transforming deoxyribonucleic acid (DNA) from Haemophilus influenzae was exposed to sonic radiation of various durations. Reductions in transforming ability of the DNA, cellular DNA uptake, and integration into the genome, and single- and double-stranded molecular weights of the transforming DNA were measured and compared. We conclude that (i) sonic radiation causes DNA strand breaks (almost always double-strand breaks with relatively few alkaline-labile bonds), the number increasing with exposure until the double-stranded molecular weight is reduced to less than 106 daltons; and (ii) since transformation is reduced about as much as integration and much more than uptake, inactivation of transforming DNA by sonic radiation appears to be caused mostly by failure of Haemophilus cells to integrate the transforming DNA that is taken into the cells. These results are similar to those for inactivation by X radiation but differ from those for ultraviolet radiation. A strand break caused by sonic radiation, however, does not necessarily inactivate the transforming DNA, whereas in the case of ionizing radiation it may. The results may be fit by the model proposed by Cato and Guild. From our data and the equation of Lacks, the minimum active site of DNA necessary for transformation and the frequency of exchanges between donor and recipient strands upon integration of transforming DNA were estimated as 0.35 × 106 to 0.7 × 106 daltons and 0.15 to 0.4 switches per 106 daltons, respectively.

Randolph, M. L.; Setlow, Jane K.

1972-01-01

48

The investigation of the dynamics of the phase transformation in triolein and oleic acid under pressure  

NASA Astrophysics Data System (ADS)

An aim of our work is the understanding of processes happening during phase transformations under the pressure in triglycerides and unsaturated fatty acids. Particles of investigated liquids possess the double bond between carbon atoms, which causes the bended shape of the particle and makes its free rotation impossible. This property causes low temperatures of melting point and high temperatures of boiling and also investigated by us phase transformations. For study of the dynamics of phase transformation in these liquids we measured light transmission and light scattering at 90 degrees angle, temperature, permittivity and internal pressure versus time. We applied pressure using computer controlled pump with a stepping motor, which makes increase of the pressure steady. The phase transformation in oleic acid lasts several seconds, in triolein it lasts several minutes. We think that the elongated time of phase transformation is caused by a hooked shape of particles of triolein and the dynamics of that process is determined by the tangling of particles. We checked the influence of smaller particles of oleic acid on the phase transformation by investigating the mixture of these liquids.

Tefelski, D. B.; Siegoczy?ski, R. M.; Rostocki, A. J.; Kos, A.; Ko?ciesza, R.; Wieja, K.

2008-07-01

49

Characterization of oil exhibiting high ?-linolenic acid from a genetically transformed canola strain  

Microsoft Academic Search

The seed oil from a genetically transformed canola (Brassica napus) containing 43% (w\\/w) of ?-linolenic acid (G, 18?3n?6), 22% linoleic acid (L, 18?2n?6), and 16% oleic acid (O, 18?1n?9) was\\u000a evaluated. In this high ?-linolenic acid canola oil (HGCO), the predominant 18?3n?6-containing triacylglycerol (TG) molecular\\u000a species were GGL (23%), GLO (20%), and GGG (11%). In the total TG, approximately 75%

Jim-Wen Liu; Stephen DeMichele; Marti Bergana; Emil Bobik; Christine Hastilow; Lu-Te Chuang; Pradip Mukerji; Yung-Sheng Huang

2001-01-01

50

Direct and efficient transformation of gaseous alkanes into carboxylic acids catalyzed by vanadium containing heteropolyacids  

Microsoft Academic Search

The vanadium containing heteropolyacids H4[PMo11VO40]×34H2O (HPA-1), H5[PMo10V2O40]×32H2O (HPA-2) and H6[PMo9V3O40]×34H2O (HPA-3) act as highly active catalysts for the direct transformation of light C1–C3 alkanes into the corresponding carboxylic acids in the presence of CO and in the K2S2O8\\/CF3COOH system. Propionic acid (ca. 70% yield), iso- and n-butyric acids (ca. 65% overall yield), and acetic acid (ca. 20%) are the major

Marina V. Kirillova; José A. L. da Silva; João J. R. Fraústo da Silva; Armando J. L. Pombeiro

2007-01-01

51

TRANSFORMATION  

SciTech Connect

Transformation, which alters the genetic makeup of an individual, is a concept that intrigues the human imagination. In Streptococcus pneumoniae such transformation was first demonstrated. Perhaps our fascination with genetics derived from our ancestors observing their own progeny, with its retention and assortment of parental traits, but such interest must have been accelerated after the dawn of agriculture. It was in pea plants that Gregor Mendel in the late 1800s examined inherited traits and found them to be determined by physical elements, or genes, passed from parents to progeny. In our day, the material basis of these genetic determinants was revealed to be DNA by the lowly bacteria, in particular, the pneumococcus. For this species, transformation by free DNA is a sexual process that enables cells to sport new combinations of genes and traits. Genetic transformation of the type found in S. pneumoniae occurs naturally in many species of bacteria (70), but, initially only a few other transformable species were found, namely, Haemophilus influenzae, Neisseria meningitides, Neisseria gonorrheae, and Bacillus subtilis (96). Natural transformation, which requires a set of genes evolved for the purpose, contrasts with artificial transformation, which is accomplished by shocking cells either electrically, as in electroporation, or by ionic and temperature shifts. Although such artificial treatments can introduce very small amounts of DNA into virtually any type of cell, the amounts introduced by natural transformation are a million-fold greater, and S. pneumoniae can take up as much as 10% of its cellular DNA content (40).

LACKS,S.A.

2003-10-09

52

A telluric-magnetotelluric survey at Mt. Hood, Oregon: A preliminary study  

Microsoft Academic Search

The survey was conducted as part of a geothermal resource assessment that had the overall objective of stimulating geothermal exploration near stratovolcanoes in he High Cascade Range. A telluric-magnetotelluric survey was chosen as the electrical resistivity technique. Data were collected in overlapping bands from 0.002 to 40 Hz, although high levels of cultural noise, coupled with instrumental problems, decreased the

N. E. Goldstein; E. Mozley

1978-01-01

53

Mössbauer spectra of 125Te in Europium tellurate between 20 and 295 K  

NASA Astrophysics Data System (ADS)

125Te Mössbauer spectra of “anti-glass” europium tellurate Eu 0.59Te 0.41O 1.72?0.28 were studied at 20, 60 and 295 K. Temperature dependent hyperfine parameters and resonant absorption intensities are interpreted in terms of anisotropic thermal vibration of Te and of some admixture of Te VI

Binczycka, H.; Hafner, S. S.; Stanek, J.; Trömel, M.

1988-08-01

54

Distinct uptake of tellurate from selenate in a selenium accumulator, Indian mustard (Brassica juncea).  

PubMed

Tellurium (Te) is widely used in industry because of its unique chemical and physical properties, and has recently become a part of everyday life as a component of phase-change optical magnetic disks. However, the recovery of Te from the environment has not been discussed yet. In this regard, we evaluated the potential use of Indian mustard (Brassica juncea), a selenium (Se) accumulator, for the phytoremediation of Te. The Indian mustard plant was exposed to selenate and tellurate and the concentrations of Se and Te and the chemical species in the plant were determined. The Indian mustard plant accumulated less Te than Se, and the amount of Te accumulated in the plant was approximately 1/69 of that of Se. Although the incorporation of selenate was reduced by increasing sulfate concentration in the medium, the incorporation of Te was not affected by it, suggesting that this plant was able to discriminate tellurate from selenate in the roots. Three Te species were detected in the plant. The major species was tellurate. The other two species were not identical to available Te standards and thus could not be identified. Consequently, the Indian mustard plant is inappropriate for the phytoremediation of Te because it can strictly distinguish tellurate from selenate. PMID:21069179

Ogra, Yasumitsu; Okubo, Eita; Takahira, Megumi

2010-05-01

55

Enhanced transformation of diphenylarsinic acid in soil under sulfate-reducing conditions.  

PubMed

Diphenylarsinic acid (DPAA) is known to be the major contaminant in soils where diphenylchloroarsine and diphenylcyanoarsine were abandoned after World Wars I and II. In this study, experimental model studies were performed to elucidate key factors regulating the transformation of DPAA under anaerobic soil conditions. The elimination of DPAA in Gleysol soils (Qiqihar and Shindori soils) was more rapid than in Mollisol and Regosol soils (Heihe and Ikarashi soils, respectively) during a 5-week incubation. No clear relationship between decreasing rates of DPAA concentrations and soil Eh values was found. The Ikarashi soil showed the slowest decrease in DPAA concentrations among the four soils, but the transformation of DPAA was notably enhanced by addition of exogenous sulfate together with acetate, cellulose or rice straw. Addition of molybdate, a specific inhibitor of sulfate reduction, resulted in the stagnation of DPAA transformation, suggesting that indigenous sulfate reducers play a role in DPAA transformation under anaerobic conditions. Arsenate, phenylarsonic acid, phenylmethylarsinic acid, diphenylmethylarsine oxide and three unknown compounds were detected as metabolites of DPAA. This is the first study to reveal enhancement of DPAA transformation under sulfate-reducing conditions. PMID:23069334

Guan, Ling; Hisatomi, Shihoko; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

2012-11-30

56

Lipoic acid prevents Cr(6+) induced cell transformation and the associated genomic dysregulation.  

PubMed

Investigation of the transcription profile of cells transformed by Cr(6+) in vivo was undertaken. The objective was to elucidate genomic changes underlying the mechanism of action of the carcinogenic dose of Cr(6+)and their prevention using metabolic antioxidant lipoic acid (LA). Cr(6+) was administered intraperitoneally to LPS+TPA challenged Swiss albino mice in host mediated cell transformation assay using peritoneal macrophages in vivo. The cell transforming potential of Cr(6+) test doses was validated by gain of anchorage independent growth potential in soft agar and loss of Fc receptor on target cells. LA was administered in equimolar doses. Compared to non-transformed cells, the gene expression profile of transformed cells was found to be dysregulated substantially and in dose dependent manner. Genes showing down regulation were found to be involved in tumour suppression, apoptosis, DNA repair, and cell-cycle. A similar response was noted in the genes pertaining to immune system, morphogenesis, cell-communication, energy-metabolism, and biosynthesis. The co-administration of lipoic acid prevented the transcription dysregulation and cell transformation by Cr(6+) in vivo. The influenced pathways seem to be crucial for progression as well as mitigation of Cr toxicity; and their response to LA indicated their critical role in mechanism of anti-carcinogenic action of LA. Results are of importance to mitigate Cr(6+) induced occupational cancer hazard. PMID:23608068

Kumar, Sushil; Nigam, Akanksha; Priya, Shivam; Bajpai, Preeti; Budhwar, Roli

2013-07-01

57

Heterogeneous catalysts for the transformation of fatty acid triglycerides and their derivatives to fuel hydrocarbons  

NASA Astrophysics Data System (ADS)

The results of studies devoted to the catalysts for transformation of fatty acid triglycerides and their derivatives to fuel hydrocarbons are presented and described systematically. Various approaches to the use of heterogeneous catalysts for the production of biofuel from these raw materials are considered. The bibliography includes 134 references.

Yakovlev, Vadim A.; Khromova, Sofia A.; Bukhtiyarov, Valerii I.

2011-10-01

58

Oxidative transformation of a naturally occurring okadaic acid diol ester by the diatom Thalassiosira weissflogii  

Microsoft Academic Search

The diarrhetic shellfish poisoning (DSP) toxin okadaic acid (1) is found in extracts of the dinoflagellate Prorocentrum lima together with a suite of diol esters such as 2. When 2 was added to the culture medium of the centric diatom Thalassiosira weissflogii, it was transformed into a range of products within three days. Three of these products, 3, 4 and

Tingmo Hu; Ian Burton; Jonathan M. Curtis; Michael A. Quilliam; John A. Walter; Anthony J. Windust; Jeffrey L. C. Wright

1999-01-01

59

In situ transformation of an aqueous amino acid at high pressures and temperatures  

Microsoft Academic Search

The stability and transformation of aqueous amino acid at high pressures and temperatures are very important in terms of the formation of interstellar organic matter, delivery of organic compounds of meteorolites, and prebiotic organic synthesis. We studied aqueous alanine saturated solid solution at pressures of several gigapascals and temperatures up to 500°C using an external heating hydrothermal diamond anvil cell

JINYANG CHEN; HONGBIN CHENG; XIAN ZHU; LUJIANG JIN; HAIFEI ZHENG

60

Trace element transformations and partitioning during the roasting of pyrite ores in the sulfuric acid industry  

Microsoft Academic Search

Total concentrations combined with chemical partitioning of trace elements (Cd, Co, Cr, Mn, Ni, Pb, Tl, and Zn) in raw pyrite ore and solid roasting wastes were investigated in order to elucidate their transformations and partitioning during the roasting of raw pyrite ores in sulfuric acid production. In order to better understand the behavior of these elements during roasting, mineral

Chunxia Yang; Yongheng Chen; Ping’an Peng; Chao Li; Xiangyang Chang; Yingjuan Wu

2009-01-01

61

Polymorphic transformations during crystallization processes of fatty acids studied with FT-IR spectroscopy  

NASA Astrophysics Data System (ADS)

Polymorphic crystallization processes of fatty acids have been studied with FT-IR spectroscopy, which is highly sensitive to structural differences in functional groups of a molecule. It has been found that structural changes take place during the crystallization of fatty acids. In the solution crystallization of stearic acid, single crystals of the E form transform to the B form. This transformation starts with a heterogeneous nucleation of the B form on the {0 0 1} faces of the single crystal of E, and the B domains spread to the whole region of the single crystal through a solid-state phase transition. In addition, the polytypic transformation from a single-layer to a double-layer structure takes place during the crystallization of the E form. In the melt crystallization of the ? phase of oleic acid, the growth mechanism greatly changes with increasing supercooling (? T). In the condition of ? T<1.5°C, the crystal edge grows as ?1, while in the case of ? T >1.5°C, the growth edge grew as ?2 initially, then changed gradually to ?1 through a solid-state phase transition. It was assumed that the lattice imperfections present in the single crystals and the relaxation rate of structural changes at the growing faces are predominant factors for the polymorphic transformations to occur during crystallization.

Kaneko, Fumitoshi; Tashiro, Kohji; Kobayashi, Masamichi

1999-03-01

62

Transformation of monoaromatic hydrocarbons to organic acids in anoxic groundwater environment  

SciTech Connect

The transformation of benzene and a series of alkylbenzenes was studied in anoxic groundwater of a shallow glacial-outwash aquifer near Bemidji, Minnesota. Monoaromatic hydrocarbons, the most water-soluble components of crude oil, were transported downgradient of an oil spill, forming a plume of contaminated groundwater. Organic acids that were not original components of the oil were identified in the anoxic groundwater. The highest concentrations of these oxidized organic compounds were found in the anoxic plume where a decrease in concentrations of structurally related alkylbenzenes was observed. These results suggest that biological transformation of benzene and alkylbenzenes to organic acid intermediates may be an important attenuation process in anoxic environments. The transformation of a complex mixture of hydrocarbons to a series of corresponding oxidation products in an anoxic subsurface environment provides new insight into in situ anaerobic degradation processes. 21 refs., 4 figs.

Cozzarelli, I.M.; Eganhouse, R.P.; Baedecker, M.J. (Geological Survey, Reston, VA (United States))

1990-01-01

63

Qualitative Differences in the Behavior of Pneumococcal Deoxyribonucleic Acids Transforming to the Same Capsular Type  

PubMed Central

A method is described for estimating quantitatively the frequency of transformation of pneumococci to new capsular types. It is found that, when S-III cells are exposed to deoxyribonucleic acid (DNA) from wild-type I strains, transformation to SI occurs at a frequency 20 to 60 times that of transformation to the binary type SI-III. SI markers on DNA isolated from binary strains behave qualitatively and quantitatively in a different manner from the same markers on DNA from wild-type I strains and will transform S-III cells only to SI-III. Strains are described which produce only one capsular polysaccharide, but which are genetically binary and carry a second capsular genome with a mutated gene so that the second polysaccharide is not produced. Stability and other characteristics of binary strains are discussed, and one hypothesis for the genetic organization of binary strains is presented. Images

Bernheimer, Harriet P.; Wermundsen, Ingbritt E.; Austrian, Robert

1967-01-01

64

Benzoic acid transformation via conjugation with peptides and final fate of conjugates in higher plants.  

PubMed

Transformation of [1(14)C]- and [7(14)C] benzoic acids in sterile seedlings of maize (Zea mays) and pea (Pisum sativum) was studied. The tested labeled compounds were supplied in plants through roots as water solutions. The larger part of the assimilated benzoic acid forms conjugates with low-molecular-weight plant peptides. As a result of hydrolytic cleavage of the conjugation products, initial labeled benzoic acid molecules and unlabeled amino acids are released. It is supposed that conjugation takes place between the benzoic acid carboxyl group and the peptide functional groups. The amino acid composition of the conjugate peptides was determined. After removal of the plants from the labeled benzoic-acids-containing medium, the amount of conjugation products gradually decreases and the process is accompanied by the emission of labeled carbon dioxide, indicating that the conjugation products are degraded and that their radioactive component carbon atoms are then oxidized to carbon dioxide. Parallel to the conjugation reaction, a smaller part of the benzoic acid that entered the plant is transformed via oxidation, as a result of which an aromatic ring is cleaved and the resulting aliphatic fragment is incorporated into regular cell metabolism. The smallest part of the assimilated benzoic acid radiolabel is incorporated into a cell biopolymer fraction. Benzoic acid, of which the radioactive label is detected in the plant subcellular organelles and finally deposited in the vacuoles, affects the cell ultrastructural organization and the activities of the main metabolic enzymes. Intensification of catabolic processes takes place, indicating an energy demand needed for xenobiotic detoxification. PMID:15964071

Chrikishvili, D; Sadunishvili, T; Zaalishvili, G

2006-07-01

65

Transformers  

NSDL National Science Digital Library

All About Circuits is a website that âÂÂprovides a series of online textbooks covering electricity and electronics.â Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Transformers, is the ninth chapter in Volume II âÂÂAlternating Current (AC). A few of the topics covered in this chapter include: Mutual inductance and basic operation; Step-up and Step-down transformers; Electrical isolation; Phasing; Winding configurations; Voltage Regulation; and finally, Special transformers and applications.. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).

Kuphaldt, Tony R.

2008-07-03

66

Conjugated Linoleic Acid Accumulation via 10Hydroxy12-Octadecaenoic Acid during Microaerobic Transformation of Linoleic Acid by Lactobacillus acidophilus  

Microsoft Academic Search

Specific isomers of conjugated linoleic acid (CLA), a fatty acid with potentially beneficial physiological and anticarcinogenic effects, were efficiently produced from linoleic acid by washed cells of Lactobacillus acidophilus AKU 1137 under microaerobic conditions, and the metabolic pathway of CLA production from linoleic acid is explained for the first time. The CLA isomers produced were identified as cis-9, trans-11- or

JUN OGAWA; KENJI MATSUMURA; SHIGENOBU KISHINO; YORIKO OMURA; SAKAYU SHIMIZU

2001-01-01

67

Surface-mediated nucleation in the solid-state polymorph transformation of terephthalic acid.  

PubMed

A molecular mechanism for nucleation for the solid-state polymorph transformation of terephthalic acid is presented. New methods recently developed in our group, aimless shooting and likelihood maximization, are employed to construct a model for the reaction coordinate for the two system sizes studied. The reaction coordinate approximation is validated using the committor probability analysis. The transformation proceeds via a localized, elongated nucleus along the crystal edge formed by fluctuations in the supramolecular synthons, suggesting a nucleation and growth mechanism in the macroscopic system. PMID:17385859

Beckham, Gregg T; Peters, Baron; Starbuck, Cindy; Variankaval, Narayan; Trout, Bernhardt L

2007-04-18

68

Enantioselective separation and transformation of metalaxyl and its major metabolite metalaxyl acid in tomato and cucumber.  

PubMed

Many studies have shown the enantioselective transformation of metalaxyl in soil and animals, but little is known about the enantioselective biotransformation of metalaxyl in plants. In this study, a sensitive and convenient chiral liquid chromatography-tandem mass spectrometry method was developed for simultaneous measurement of the enantiomers of metalaxyl and its major metabolite, metalaxyl acid, in tomato and cucumber. Separation was by reversed-phase chromatography on a Chiralcel OD-RH column under isocratic conditions using acetonitrile-water (60/40, v/v) as mobile phase. The proposed method was successfully applied to investigate the possible enantioselective transformation of metalaxyl as well as the formation of metalaxyl acid in tomato and cucumber. In both vegetables, the (-)-R-enantiomer was preferentially degraded, resulting in relative enrichment of the (+)-S-enantiomer. Furthermore, formation of the metalaxyl acid enantiomers was also shown to be enantioselective, with the R-metalaxyl acid formed at a faster rate. This is the first evidence of enantioselective transformation of metalaxyl in vegetables, and the results should be considered in future environmental risk and food safety evaluations. PMID:23768319

Li, Yuanbo; Dong, Fengshou; Liu, Xingang; Xu, Jun; Chen, Xiu; Han, Yongtao; Cheng, Youpu; Jian, Qiu; Zheng, Yongquan

2013-11-01

69

Suppression of oncogene-induced transformation by quercetin and retinoic acid in rat liver epithelial cells.  

PubMed

AP1 is a heterodimeric complex containing products of the Jun and Fos oncogene families. The c-fos and c-jun protooncogenes act as transcriptional activator for numerous cellular genes, and the overexpression of these genes may cause malignant transformation. In this study, to show evidence of a possible inhibition of AP1 transcriptional activity in molecular mechanisms of foodborne molecules, known to be negative modulators of carcinogenesis, we established two rat liver epithelial (REL) cell lines overexpressing either c-fos (43C line) or c-jun (RELcJ1 line) oncoproteins. Contrary to the 43C line, which was spontaneously transformed, the c-jun-transfected REL cells were only transformed in vitro after 12-O-tetra-decanoylphorbol 13-acetate (TPA) exposure. All trans-retinoic acid (RA) abolished the transformation of the 43C line and TPA-treated RELcJ1 cells, suggesting that RA could decrease AP1 activity in these cells despite c-fos or c-jun overexpression. Furthermore, we show for the first time that a flavonoid, quercetin, which is a natural component of vegetables, inhibited only the transformation of the 43C line. The spontaneous transformation of the c-fos-transfected REL cells was associated with the appearance of c-fos/AP1 complexes binding TRE, suggesting that c-fos/AP1 complexes are involved in the antitransforming mechanism of quercetin. PMID:8777434

Lagarrigue, S; Chaumontet, C; Heberden, C; Martel, P; Gaillard-Sanchez, I

1995-01-01

70

FTIR, Raman, and UV-Vis spectroscopic and DFT investigations of the structure of iron-lead-tellurate glasses.  

PubMed

In this work, the effects of iron ion intercalations on lead-tellurate glasses were investigated via FTIR, Raman and UV-Vis spectroscopies. This homogeneous glass system has compositions xFe(2)O(3)?(100-x)[4TeO(2)?PbO(2)], where x?=?0-60 mol%. The presented observations in these mechanisms show that the lead ions have a pronounced affinity towards [TeO(3)] structural units, resulting in the deformation of the Te-O-Te linkages, and leading to the intercalation of [PbO( n )] (n?=?3, 4) and [FeO( n )] (n?=?4, 6) entities in the [TeO(4)] chain network. The formation of negatively charged [FeO(4)](1-) structural units implies the attraction of Pb(2+) ions in order to compensate for this electrical charge. Upon increasing the Fe(2)O(3) content to 60 mol%, the network can accommodate an excess of oxygen through the formation of [FeO(6)] structural units and the conversion of [TeO(4)] into [TeO(3)] structural units. For even higher Fe(2)O(3) contents, Raman spectra indicate a greater degree of depolymerization of the vitreous network than FTIR spectra do. The bands due to the Pb-O bond vibrations are very strongly polarized and the [TeO(4)] structural units convert into [TeO(3)] units via an intermediate coordination stage termed "[TeO(3+1)]" structural units. Our UV-Vis spectroscopic data show two mechanisms: (i) the conversion of the Fe(3+) to Fe(2+) at the same time as the oxidation of Pb(2+) to Pb(+4) ions for samples with low Fe(2)O(3) contents; (ii) when the Fe(2)O(3) content is high (x???50 mol%), the Fe(2+) ions capture positive holes and are transferred to Fe(3+) ions through a photochemical reaction, while the Pb(2+) ions are formed by the reduction of Pb(4+) ions. DFT calculations show that the addition of Fe(2)O(3) to lead-tellurate glasses seems to break the axial Te-O bonds, and the [TeO(4)] structural units are gradually transformed into [TeO(3+1)]- and [TeO(3)]-type polyhedra. Analyzing these data further indicates a gradual conversion of the lead ions from covalent to ionic environment. There is then a charge transfer between the tri- and tetracoordinated tellurium atoms due to the capacity of the lead-tellurate network to form the appropriate coordination environments containing structural units of opposite charge, such as iron ions, [FeO(4)](1-). PMID:21174135

Rada, Simona; Dehelean, Adriana; Culea, Eugen

2011-08-01

71

Transposon-5 mutagenesis transforms Corynebacterium matruchotii to synthesize novel hybrid fatty acids that functionally replace corynomycolic acid.  

PubMed

Enzymes within the biosynthetic pathway of mycolic acid (C(60)-C(90) a-alkyl,b-hydroxyl fatty acid) in Mycobacterium tuberculosis are attractive targets for developing new anti-tuberculosis drugs. We have turned to the simple model system of Corynebacterium matruchotii to study the terminal steps in the anabolic pathway of a C32 mycolic acid called corynomycolic acid. By transposon-5 mutagenesis, we transformed C. matruchotii into a mutant that is unable to synthesize corynomycolic acid. Instead, it synthesized two related series of novel fatty acids that were released by saponification from the cell wall fraction and from two chloroform/methanol-extractable glycolipids presumed to be analogues of trehalose mono- and di-corynomycolate. By chemical analyses and MS, we determined the general structure of the two series to be 2,4,6,8,10-penta-alkyl decanoic acid for the larger series (C(70)-C(77)) and 2,4,6,8-tetra-alkyl octanoic acid for the smaller series (C(52)-C(64)), both containing multiple keto groups, hydroxy groups and double bonds. The mutant was temperature-sensitive, aggregated extensively, grew very slowly relative to the wild type, and was resistant to the presence of lysozyme. We suggest that a regulatory protein that normally prevents the transfer of the condensation product back to b-ketoacyl synthase in the corynomycolate synthase system of the wild type was inactivated in the mutant. This will result in multiple Claisen-type condensation and the formation of two similar series of these complex hybrid fatty acids. A similar protein in M. tuberculosis would be an attractive target for new drug discovery. PMID:12879902

Takayama, Kuni; Hayes, Barry; Vestling, Matha M; Massey, Randall J

2003-07-15

72

Fat transforms ascorbic acid from inhibiting to promoting acid-catalysed N?nitrosation  

PubMed Central

Background The major potential site of acid nitrosation is the proximal stomach, an anatomical site prone to a rising incidence of metaplasia and adenocarcinoma. Nitrite, a pre?carcinogen present in saliva, can be converted to nitrosating species and N?nitroso compounds by acidification at low gastric pH in the presence of thiocyanate. Aims To assess the effect of lipid and ascorbic acid on the nitrosative chemistry under conditions simulating the human proximal stomach. Methods The nitrosative chemistry was modelled in vitro by measuring the nitrosation of four secondary amines under conditions simulating the proximal stomach. The N?nitrosamines formed were measured by gas chromatography–ion?trap tandem mass spectrometry, while nitric oxide and oxygen levels were measured amperometrically. Results In absence of lipid, nitrosative stress was inhibited by ascorbic acid through conversion of nitrosating species to nitric oxide. Addition of ascorbic acid reduced the amount of N?nitrosodimethylamine formed by fivefold, N?nitrosomorpholine by >1000?fold, and totally prevented the formation of N?nitrosodiethylamine and N?nitrosopiperidine. In contrast, when 10% lipid was present, ascorbic acid increased the amount of N?nitrosodimethylamine, N?nitrosodiethylamine and N?nitrosopiperidine formed by approximately 8?, 60? and 140?fold, respectively, compared with absence of ascorbic acid. Conclusion The presence of lipid converts ascorbic acid from inhibiting to promoting acid nitrosation. This may be explained by nitric oxide, formed by ascorbic acid in the aqueous phase, being able to regenerate nitrosating species by reacting with oxygen in the lipid phase.

Combet, E; Paterson, S; Iijima, K; Winter, J; Mullen, W; Crozier, A; Preston, T; McColl, K E L

2007-01-01

73

Inhibition of Myc-induced cell transformation by brain acid-soluble protein 1 (BASP1).  

PubMed

Cell transformation by the Myc oncoprotein involves transcriptional activation or suppression of specific target genes with intrinsic oncogenic or tumor-suppressive potential, respectively. We have identified the BASP1 (CAP-23, NAP-22) gene as a novel target suppressed by Myc. The acidic 25-kDa BASP1 protein was originally isolated as a cortical cytoskeleton-associated protein from rat and chicken brain, but has also been found in other tissues and subcellular locations. BASP1 mRNA and protein expression is specifically suppressed in fibroblasts transformed by the v-myc oncogene, but not in cells transformed by other oncogenic agents. The BASP1 gene encompasses 2 exons separated by a 58-kbp intron and a Myc-responsive regulatory region at the 5' boundary of untranslated exon 1. Bicistronic expression of BASP1 and v-myc from a retroviral vector blocks v-myc-induced cell transformation. Furthermore, ectopic expression of BASP1 renders fibroblasts resistant to subsequent cell transformation by v-myc, and exogenous delivery of the BASP1 gene into v-myc-transformed cells leads to significant attenuation of the transformed phenotype. The inhibition of v-myc-induced cell transformation by BASP1 also prevents the transcriptional activation or repression of known Myc target genes. Mutational analysis showed that the basic N-terminal domain containing a myristoylation site, a calmodulin binding domain, and a putative nuclear localization signal is essential for the inhibitory function of BASP1. Our results suggest that down-regulation of the BASP1 gene is a necessary event in myc-induced oncogenesis and define the BASP1 protein as a potential tumor suppressor. PMID:19297618

Hartl, Markus; Nist, Andrea; Khan, M Imran; Valovka, Taras; Bister, Klaus

2009-04-01

74

Inhibition of Myc-induced cell transformation by brain acid-soluble protein 1 (BASP1)  

PubMed Central

Cell transformation by the Myc oncoprotein involves transcriptional activation or suppression of specific target genes with intrinsic oncogenic or tumor-suppressive potential, respectively. We have identified the BASP1 (CAP-23, NAP-22) gene as a novel target suppressed by Myc. The acidic 25-kDa BASP1 protein was originally isolated as a cortical cytoskeleton-associated protein from rat and chicken brain, but has also been found in other tissues and subcellular locations. BASP1 mRNA and protein expression is specifically suppressed in fibroblasts transformed by the v-myc oncogene, but not in cells transformed by other oncogenic agents. The BASP1 gene encompasses 2 exons separated by a 58-kbp intron and a Myc-responsive regulatory region at the 5? boundary of untranslated exon 1. Bicistronic expression of BASP1 and v-myc from a retroviral vector blocks v-myc-induced cell transformation. Furthermore, ectopic expression of BASP1 renders fibroblasts resistant to subsequent cell transformation by v-myc, and exogenous delivery of the BASP1 gene into v-myc-transformed cells leads to significant attenuation of the transformed phenotype. The inhibition of v-myc-induced cell transformation by BASP1 also prevents the transcriptional activation or repression of known Myc target genes. Mutational analysis showed that the basic N-terminal domain containing a myristoylation site, a calmodulin binding domain, and a putative nuclear localization signal is essential for the inhibitory function of BASP1. Our results suggest that down-regulation of the BASP1 gene is a necessary event in myc-induced oncogenesis and define the BASP1 protein as a potential tumor suppressor.

Hartl, Markus; Nist, Andrea; Khan, M. Imran; Valovka, Taras; Bister, Klaus

2009-01-01

75

Photodynamic Action on Native and Denatured Transforming Deoxyribonucleic Acid from Haemophilus influenzae  

PubMed Central

The photodynamic inactivation of native or denatured transforming deoxyribonucleic acid (DNA) from Haemophilus influenzae is described. The inactivation at the same pH was higher for denatured than native DNA. At acidic pH, the inactivation both for native and denatured DNA was faster than at alkaline pH. The guanine content of photoinactivated native DNA at neutral pH was less than untreated DNA. The inactivation of biological activity was more extensive than the alteration of guanine. The absorption spectrum of photoinactivated native or denatured DNA was only slightly different than the control DNA at the different experimental conditions.

Leon, Manuel Ponce-De; Cabrera-Juarez, Emiliano

1970-01-01

76

Retinoic acid modulates rat Ito cell proliferation, collagen, and transforming growth factor beta production.  

PubMed Central

Recent studies suggest that vitamin A plays an inhibitory role with respect to "activation" of the hepatic Ito cell, a likely effector of hepatic fibrogenesis. Ito cell "activation" during fibrogenesis is characterized by a decrease in intracellular vitamin A and an increase in cellular proliferation and collagen production. To explore the hypothesis that retinoids have the capacity to diminish Ito cell activation, cultured Ito cells were exposed to retinoic acid and its effects assessed on three key features: cell proliferation, collagen protein production and mRNA abundance, and transforming growth factor beta protein production. Retinoic acid was 100-1,000X more potent than retinol with respect to inhibition of Ito cell proliferation. Interstitial collagen and transforming growth factor beta production were also reduced by 10(-6) M retinoic acid. The relative abundance of type I collagen mRNA however, was not significantly altered. By contrast, retinoic acid administration to rats caused a marked reduction in the abundance of type I collagen mRNA in both total hepatic and purified Ito cell RNA. The relative abundance of rat hepatic fibronectin or apolipoprotein E mRNA was not significantly altered. These studies demonstrate that retinoic acid can differentially modulate several key features of hepatic fibrogenesis in vitro and in vivo. Images

Davis, B H; Kramer, R T; Davidson, N O

1990-01-01

77

Estimation of water transport from oscillations of the on-shore telluric field generated by tides  

NASA Astrophysics Data System (ADS)

On-shore measurements of telluric field oscillations have been used together with electric field acquired in a submarine cable crossing a channel (in Aveiro area) to estimate the water transport through the channel. The on-shore N-S dipole was calibrated by correlating the lunar tidal water transport and the corresponding on-shore motionally tidal electric field. A calibration factor of 7350 m 3 s - 1for each mV/km, with motionally induced origin, was estimated. Theoretical polarization ellipses of the electric field with tidal origin and telluric field attenuation during inland propagation agreed very well with observed values. The results showed that it is possible to estimate the water transport from on-shore measurements.

Monteiro Santos, Fernando A.; Nolasco, Rita; Soares, António; Dias, João M.; Bernardo, Ivo

2007-11-01

78

Spectroscopic studies of copper ions doped in tellurate glasses obtained by sol - gel method  

NASA Astrophysics Data System (ADS)

The preparation of copper nitrate doped tellurate glasses by sol- gel method and spectroscopic studies of this tellurate system are reported. FTIR spectroscopy results show that this glass consists of [TeO6], [TeO4] and [TeO3] structural units and indicate that six- coordinated tellurium (VI) in [TeO6] units were partially changed to fourcoordinated tellurium (IV) in [TeO4] units during the doping with Cu(NO3)2. EPR spectra of the studied glasses were obtained due to the presence of Cu2+ paramagnetic ions and reveal the local order in matrix, the distribution and valence state of cooper ions. Thus, the EPR spectra show a partially resolved parallel hyperfine structure and no resolved perpendicular structure. The EPR spectra could be a superposition of two signals, one due to isolated Cu2+ ions in axial neighborhood, and the other due to the presence of magnetically coupled Cu2+ species.

Dehelean, A.; Rada, S.; Danciu, V.; Culea, E.; Stan, M.; Popa, A.; Raita, O.

2012-02-01

79

The influence of some amino acids on calcium oxalate dihydrate transformation  

NASA Astrophysics Data System (ADS)

The influence of histidine (His), serine (Ser), tryptophan (Trp), glutamic acid (Glu) and ornithine (Orn) on the formation of calcium oxalate hydrates and the transformation of calcium oxalate dihydrate (COD) to the thermodynamically stable monohydrate (COM) has been studied. Simultaneous production of two hydrates (COM and COD) was initiated by mixing sodium oxalate solutions containing the respective amino acid with equal volumes of calcium chloride solutions. A combination of optical microscopy, X-ray diffraction, thermogravimetric analysis, size distribution measurements and atomic absorption spectroscopy were used to characterize the processes involved. The examined amino acids have a specific effect on the nucleation of calcium oxalates: Trp and His promote the formation of COD over COM while the others favour the formation of COM. The presence of Trp and Ser influenced the morphology of COD crystals. The processes comprising the transformation, the dissolution of COD and the growth of COM, were examined separately. The corresponding growth and dissolution rates have been determined and it was found that Trp and Ser affected the transformation kinetics by changing the rate controlling mechanism of COD dissolution from diffusion to a surface controlled reaction.

Bre?evi?, Lj.; Kralj, D.

1986-12-01

80

Impact of the degree of secondary transformation on acid–base properties of organic compounds in mucks  

Microsoft Academic Search

The differences in the water adsorptivity index, variable surface charge, surface dissociation constants, and the content of hydrophobic and hydrophilic bound amino acids were studied in 14 peat muck soils at various phases of the mucking process. In general, the total concentration of bound amino acids was the highest in secondary transformed mucks. The lowest content of amino acids was

Zofia Soko?owska; Lech Szajdak; Dorota Matyka-Sarzy?ska

2005-01-01

81

Transformation of cellulose and its derived carbohydrates into formic and lactic acids catalyzed by vanadyl cations.  

PubMed

The transformation of cellulose or cellulose-derived carbohydrates into platform chemicals is the key to establish biomass-based sustainable chemical processes. The systems able to catalyze the conversion of cellulose into key chemicals in water without the consumption of hydrogen are limited. We report that simple vanadyl (VO(2+) ) cations catalyze the conversions of cellulose and its monomer, glucose, into lactic acid and formic acid in water. We have discovered an interesting shift of the major product from formic acid to lactic acid on switching the reaction atmosphere from oxygen to nitrogen. Our studies suggest that VO(2+) catalyzes the isomerization of glucose to fructose, the retro-aldol fragmentation of fructose to two trioses, and the isomerization of trioses, which leads to the formation of lactic acid under anaerobic conditions. The oxidative cleavage of C?C bonds in the intermediates caused by the redox conversion of VO2 (+) /VO(2+) under aerobic conditions results in formic acid and CO2 . We demonstrate that the addition of an alcohol suppresses the formation of CO2 and enhances the formic acid yield significantly to 70-75?%. PMID:24798653

Tang, Zhenchen; Deng, Weiping; Wang, Yanliang; Zhu, Enze; Wan, Xiaoyue; Zhang, Qinghong; Wang, Ye

2014-06-01

82

[Effect of humic acids on migration and transformation of NH4(+) -N in saturated aquifer].  

PubMed

Isothermal adsorption experiment was used to study the adsorbing process of NH4(+) -N in quartz sands under the conditions with and without humic acid; the Langmuir and Freundlich equations were used to fit the absorption result and the maximum adsorption capacity of NH4(+) -N by quarts sands was calculated. Through the soil column experiments, the concentration of NH4(+) -N, NO3(-) -N and NO2(-) -N in effluent water in the tested soil column was investigated, and the effect of humic acid on migration and transformation of NH4(+) -N in saturated aquifer was analyzed, and Pseudo-second-order Kinetics Equation and Two-step Adsorption Kinetics Rate Equation were applied to fit the kinetic processes. The results showed that both Langmuir and Freundlich models can well describe the isothermal adsorption process of NH4(+) -N on the surface of quartz sands, which means that NH4(+) -N adsorbed by the quartz sand was mainly in the form of monolayer adsorption. The humic acid could increase the adsorption capacity of NH4(+) -N on quartz sand, and the saturated adsorption capacity was 0.354 mg x g(-1) under the condition with humic acid and 0.205 mg x g(-1) with the absence of humic acid. The experiment indicated that humic acid increased the adsorption capacity of NH4(+) -N on the surface of quartz sand by increasing adsorption space in the initial stage. After saturation, humic acid influenced the migration and transformation of NH4(+) -N to NO3(-) -N and NO2(-) -N probably through providing carbon source and energy for microorganisms such as nitrifying bacteria and then resulting in lower NH4(+) -N concentration in effluent water. Both Pseudo-second-order Kinetics Equation and Two-step Adsorption Kinetics Rate Equations can well describe the process of NH4(+) -N adsorption kinetics on quartz sand (R2 = 0.997 7 and R2 = 0.998 1 with humic acid; R2 = 0.992 3 and R2 = 0.994 4 without humic acid), indicating that this process was chemical adsorption. By comparing the adsorption rate coefficient of Two-step Adsorption Kinetics Rate Equation k3 (0.247 and 0.143, respectively) and k4 (0.006 27 and 0.001 7) between the treatments with and without humic acid, it can be referred that NH4(+) -N was non-orientated adsorption on active points of the quartz sand at the initial stage, and the humic acid could increase the equilibrium adsorption quantity(q(e)) of NH4(+) -N on quartz sands. PMID:22295635

Meng, Qing-Jun; Zhang, Yan; Feng, Qi-Yan; Zhang, Shuang-Sheng

2011-11-01

83

Anaerobic transformation of alkanes to fatty acids by a sulfate-reducing bacterium, strain Hxd3.  

PubMed

Strain Hxd3, an alkane-degrading sulfate reducer previously isolated and described by Aeckersberg et al. (F. Aeckersberg, F. Bak, and F. Widdel, Arch. Microbiol. 156:5-14, 1991), was studied for its alkane degradation mechanism by using deuterium and (13)C-labeled compounds. Deuterated fatty acids with even numbers of C atoms (C-even) and (13)C-labeled fatty acids with odd numbers of C atoms (C-odd) were recovered from cultures of Hxd3 grown on perdeuterated pentadecane and [1,2-(13)C(2)]hexadecane, respectively, underscoring evidence that C-odd alkanes are transformed to C-even fatty acids and vice versa. When Hxd3 was grown on unlabeled hexadecane in the presence of [(13)C]bicarbonate, the resulting 15:0 fatty acid, which was one carbon shorter than the alkane, incorporated a (13)C label to form its carboxyl group. The same results were observed when tetradecane, pentadecane, and perdeuterated pentadecane were used as the substrates. These observations indicate that the initial attack of alkanes includes both carboxylation with inorganic bicarbonate and the removal of two carbon atoms from the alkane chain terminus, resulting in a fatty acid one carbon shorter than the original alkane. The removal of two terminal carbon atoms is further evidenced by the observation that the [1,2-(13)C(2)]hexadecane-derived fatty acids contained either two (13)C labels located exclusively at their acyl chain termini or none at all. Furthermore, when perdeuterated pentadecane was used as the substrate, the 14:0 and 16:0 fatty acids formed both carried the same numbers of deuterium labels, while the latter was not deuterated at its carboxyl end. These observations provide further evidence that the 14:0 fatty acid was initially formed from perdeuterated pentadecane, while the 16:0 fatty acid was produced after chain elongation of the former fatty acid with nondeuterated carbon atoms. We propose that strain Hxd3 anaerobically transforms an alkane to a fatty acid through a mechanism which includes subterminal carboxylation at the C-3 position of the alkane and elimination of the two adjacent terminal carbon atoms. PMID:12839758

So, Chi Ming; Phelps, Craig D; Young, L Y

2003-07-01

84

Anaerobic Transformation of Alkanes to Fatty Acids by a Sulfate-Reducing Bacterium, Strain Hxd3  

PubMed Central

Strain Hxd3, an alkane-degrading sulfate reducer previously isolated and described by Aeckersberg et al. (F. Aeckersberg, F. Bak, and F. Widdel, Arch. Microbiol. 156:5-14, 1991), was studied for its alkane degradation mechanism by using deuterium and 13C-labeled compounds. Deuterated fatty acids with even numbers of C atoms (C-even) and 13C-labeled fatty acids with odd numbers of C atoms (C-odd) were recovered from cultures of Hxd3 grown on perdeuterated pentadecane and [1,2-13C2]hexadecane, respectively, underscoring evidence that C-odd alkanes are transformed to C-even fatty acids and vice versa. When Hxd3 was grown on unlabeled hexadecane in the presence of [13C]bicarbonate, the resulting 15:0 fatty acid, which was one carbon shorter than the alkane, incorporated a 13C label to form its carboxyl group. The same results were observed when tetradecane, pentadecane, and perdeuterated pentadecane were used as the substrates. These observations indicate that the initial attack of alkanes includes both carboxylation with inorganic bicarbonate and the removal of two carbon atoms from the alkane chain terminus, resulting in a fatty acid one carbon shorter than the original alkane. The removal of two terminal carbon atoms is further evidenced by the observation that the [1,2-13C2]hexadecane-derived fatty acids contained either two 13C labels located exclusively at their acyl chain termini or none at all. Furthermore, when perdeuterated pentadecane was used as the substrate, the 14:0 and 16:0 fatty acids formed both carried the same numbers of deuterium labels, while the latter was not deuterated at its carboxyl end. These observations provide further evidence that the 14:0 fatty acid was initially formed from perdeuterated pentadecane, while the 16:0 fatty acid was produced after chain elongation of the former fatty acid with nondeuterated carbon atoms. We propose that strain Hxd3 anaerobically transforms an alkane to a fatty acid through a mechanism which includes subterminal carboxylation at the C-3 position of the alkane and elimination of the two adjacent terminal carbon atoms.

So, Chi Ming; Phelps, Craig D.; Young, L. Y.

2003-01-01

85

Characteristic transformation of humic acid during photoelectrocatalysis process and its subsequent disinfection byproduct formation potential.  

PubMed

In this study, degradation of humic acid (HA) via photoelectrocatalysis (PEC) process and corresponding disinfection byproduct formation potential (DBPFP) were investigated. Particularly, structure variation and subsequent DBPFP of HA during PEC treatment were correlated. The PEC process was found to be effective in reducing dissolved organic carbon concentration by 75.0% and UV absorbance at 254 nm by 92.0%. Furthermore, 90.3% of haloacetic acids formation potential and 89.8% of trihalomethanes formation potential were reduced within 180 min. Based on molecular weight and resin fraction results, it was demonstrated that HA with large aromatic, hydrophobic and long aliphatic chain organics were transformed into small and hydrophilic organics during PEC process. Combined with the fourier transform infrared spectra and (13)C nuclear magnetic resonance spectra analysis of HA fractions, it was concluded that phenolic hydroxyl and conjugated double bonds tended to be attacked by hydroxyl radicals during PEC process; these groups were reactive with chlorine to produce disinfection byproducts (DBP), especially trihalomethane and trichloroacetic acid. By contrast, amino, carboxyl and alcoholic hydroxyl groups were relatively difficult to be oxidized during PEC process; these groups had the potential to form dichloroacetic acid during chlorination. Results of these studies confirmed that PEC process was a safe and effective technique to decrease DBP formation significantly in water treatment plant. PMID:21955983

Li, Angzhen; Zhao, Xu; Liu, Huijuan; Qu, Jiuhui

2011-11-15

86

Control of the uptake of amino acids by serum in chick embryo cells, untransformed or transformed with rous sarcoma virus  

Microsoft Academic Search

Summary Forty to fifty minutes after removal of serum, the net total uptake of amino acids in growing secondary cultures of normal or virus-transformed chick embryo cells, stopped or proceeded only at a highly reduced rate. In both normal and transformed cells, theinitial (0–40 min) rate of the above uptake was the same in the absence of serum as in

P. M. Bhargava; P. Vigier

1976-01-01

87

Polymorphic transformation of l-glutamic acid monitored using combined on-line video microscopy and X-ray diffraction  

Microsoft Academic Search

Enhancement of process monitoring for detecting transformations of the organic solid state is an important, strategic area currently of substantial interest particularly to the pharmaceutical sector and, more generally, manufacturers of speciality chemical products. A feasibility study is reported in which a solution-mediated polymorphic transformation of l-glutamic acid (LGA) was monitored using, concurrently, both video microscopy accompanied by advanced image

Spoorthi Dharmayat; Jorge Calderon De Anda; Robert B. Hammond; Xaiojun Lai; Kevin J. Roberts; Xue Z. Wang

2006-01-01

88

Gallium(III) triflate: an efficient and a sustainable Lewis acid catalyst for organic synthetic transformations.  

PubMed

Green chemical processes play a crucial role in sustainable development, and efficient recyclable catalysts that can be conveniently applied in various chemical reactions are the key elements for the development of sustainable synthetic processes. Many organic transformations rely on Lewis and Brønsted acid catalysts, and such molecules have been widely studied in organic synthesis. Over the years, researchers have looked for Lewis acid catalysts that provide high selectivity and high turnover frequency but are also stable in aqueous media and recoverable. Since the first preparation of trifluoromethanesulfonic acid by Hazeldine (triflic acid, HOTf), researchers have synthesized and used numerous metal triflates in a variety of organic reactions. Even though the rare earth metal triflates have played a major role in these studies, the majority of rare earth triflates lack one or more of the primary properties of sustainable catalysts: low cost and easy availability of the metals, easy preparation of triflates, aqueous/thermal stability, recyclability, and catalytic efficiency. In this Account, we describe the synthetic applications of Ga(OTf)(3) and its advantages over similar catalysts. Ga(OTf)(3) can be conveniently prepared from gallium metal or gallium chloride in excess of trifluoromethanesulfonic acid (triflic acid) under reflux. Among many Lewis acid catalysts recently studied, Ga(OTf)(3) is water tolerant and soluble and requires very low catalyst loading to drive various acid-catalyzed reactions including Friedel-Crafts alkylation, hydroxyalkylation, and acylation selectively and efficiently. In many reactions Ga(OTf)(3) demonstrated high chemo- and regioselectivity, high yields, excellent stability, and recyclability. We successfully synthesized many biologically active heterocycles and their fluoroanalogs under mild conditions. Many challenging reactions such as the ketonic Strecker reactions proceed efficiently via Ga(OTf)(3) catalysis. Because it is stable in water, this catalyst provides the opportunity to study substrates and develop new synthetic protocols in aqueous media, significantly reducing the production of hazardous waste from organic solvents and toxic catalyst systems. PMID:22148160

Prakash, G K Surya; Mathew, Thomas; Olah, George A

2012-04-17

89

Growth and shape transformations of giant phospholipid vesicles upon interaction with an aqueous oleic acid suspension.  

PubMed

The interaction of two types of vesicle systems was investigated: micrometer-sized, giant unilamellar vesicles (GUVs) formed from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and submicrometer-sized, large unilamellar vesicles (LUVs) formed from oleic acid and oleate, both in a buffered aqueous solution (pH 8.8). Individual POPC GUVs were transferred with a micropipette into a suspension of oleic acid/oleate LUVs, and the shape changes of the GUVs were monitored using optical microscopy. The behavior of POPC GUVs upon transfer into a 0.8mM suspension of oleic acid, in which oleic acid/oleate forms vesicular bilayer structures, was qualitatively different from the behavior upon transfer into a 0.3mM suspension of oleic acid/oleate, in which oleic acid/oleate is predominantly present in the form of monomers and possibly non-vesicular aggregates. In both cases, changes in vesicle morphology were observed within tens of seconds after the transfer. After an initial increase of the vesicle cross-section, the vesicle started to evaginate, spawning dozens of satellite vesicles connected to the mother vesicle with narrow necks or tethers. In 60% of the cases of transfer into a 0.8mM oleic acid suspension, the evagination process reversed and proceeded to the point where the membrane formed invaginations. In some of these cases, several consecutive transitions between invaginated and evaginated shapes were observed. In the remaining 40% of the cases of transfer into the 0.8mM oleic acid suspension and in all cases of vesicle transfer into the 0.3mM oleic acid suspension, no invaginations nor subsequent evaginations were observed. An interpretation of the observed vesicle shape transformation on the basis of the bilayer-couple model is proposed, which takes into account uptake of oleic acid/oleate molecules by the POPC vesicles, oleic acid flip-flop processes and transient pore formation. PMID:19477312

Peterlin, Primoz; Arrigler, Vesna; Kogej, Ksenija; Svetina, Sasa; Walde, Peter

2009-06-01

90

Complexation of chitosan with acetic acid according to Fourier transform Raman spectroscopy data  

NASA Astrophysics Data System (ADS)

The results of the interaction between the protonated chitosan (CHI) macromolecule and the acetate ion in dilute acetic acid solutions were studied by Fourier transform Raman spectroscopy and quantum-chemical modeling. The complexation of CHI with the acetate ion showed itself as the 934 cm-1 band in the Raman spectrum, which suggests the formation of [CHI+ · CH3COO-] type ion pairs. It was concluded that a comparative analysis of the integrated intensities of the Raman bands in the range 880-940 cm-1 makes it possible to judge about the relative content of hydrated acetate ions, CHI macromolecules of the [CHI+ · CH3COO-] complex, and acetic acid molecules not involved in CHI protonation.

Mikhailov, G. P.; Tuchkov, S. V.; Lazarev, V. V.; Kulish, E. I.

2014-06-01

91

Enhancement of the reductive transformation of pentachlorophenol by polycarboxylic acids at the iron oxide–water interface  

Microsoft Academic Search

The enhancement effect of polycarboxylic acids on reductive dechlorination transformation of pentachlorophenol (PCP) reacting with iron oxides was studied in anoxic suspension. Batch experiments were performed with three species of iron oxides (goethite, lepidocrocite and hematite) and four species of polycarboxylic acids (oxalate, citrate, succinate, and tartrate) through anoxic abiotic reactors. The chemical analyses and morphological observation from scanning and

Fangbai Li; Xugang Wang; Yongtao Li; Chengshuai Liu; Fang Zeng; Lijia Zhang; Mingde Hao; Huada Ruan

2008-01-01

92

Perfluorobutyric acid and its monohydrate: a chirped pulse and cavity based fourier transform microwave spectroscopic study.  

PubMed

Rotational spectra of perfluorobutyric acid (PFBA) and its monohydrate were studied with a broadband chirped pulse and a narrow-band cavity based Fourier transform microwave spectrometer, and high-level ab initio calculations. Extensive conformational searches were performed for both the acid and its monohydrate at the MP2/6-311++G(2d,p) level of theory. Two and three conformers were predicted to exist for PFBA and its monohydrate, respectively. One set of rotational transitions was observed and assigned for each, PFBA and its monohydrate. Based on the measured broadband spectra, we confidently conclude that only one dominant conformer exists in each case. The orientation of the hydroxyl group in PFBA was determined by using isotopic analysis. Comparison of the observed transition intensities and the calculated electric dipole moment components allowed us to identify the most stable monohydrate conformation, which takes on an insertion hydrogen-bonding topology. Comparisons to the shorter chain analogues, that is, trifluoroacetic acid, perfluoropropionic acid, and their monohydrates, are made to elucidate the general trend in their conformational preference and binding topologies. PMID:24756992

Thomas, Javix; Serrato, Agapito; Lin, Wei; Jäger, Wolfgang; Xu, Yunjie

2014-05-12

93

Role of Oxalic Acid Overexcretion in Transformations of Toxic Metal Minerals by Beauveria caledonica  

PubMed Central

The fungus Beauveria caledonica was highly tolerant to toxic metals and solubilized cadmium, copper, lead, and zinc minerals, converting them into oxalates. This fungus was found to overexcrete organic acids with strong metal-chelating properties (oxalic and citric acids), suggesting that a ligand-promoted mechanism was the main mechanism of mineral dissolution. Our data also suggested that oxalic acid was the main mineral-transforming agent. Cadmium, copper, and zinc oxalates were precipitated by the fungus in the local environment and also in association with the mycelium. The presence of toxic metal minerals often led to the formation of mycelial cords, and in the presence of copper-containing minerals, these cords exhibited enhanced excretion of oxalic acid, which resulted in considerable encrustation of the cords by copper oxalate hydrate (moolooite). It was found that B. caledonica hyphae and cords were covered by a thick hydrated mucilaginous sheath which provided a microenvironment for chemical reactions, crystal deposition, and growth. Cryo-scanning electron microscopy revealed that mycogenic metal oxalates overgrew parental fungal hyphae, leaving a labyrinth of fungal tunnels within the newly formed mineral matter. X-ray absorption spectroscopy revealed that oxygen ligands played a major role in metal coordination within the fungal biomass during the accumulation of mobilized toxic metals by B. caledonica mycelium; these ligands were carboxylic groups in copper phosphate-containing medium and phosphate groups in pyromorphite-containing medium.

Fomina, M.; Hillier, S.; Charnock, J. M.; Melville, K.; Alexander, I. J.; Gadd, G. M.

2005-01-01

94

Drinking water disinfection byproduct iodoacetic acid induces tumorigenic transformation of NIH3T3 cells.  

PubMed

Iodoacetic acid (IAA) and iodoform (IF) are unregulated iodinated disinfection byproducts (DBPs) found in drinking water. Their presence in the drinking water of China has not been documented. Recently, the carcinogenic potential of IAA and IF has been a concern because of their mutagenicity in bacteria and genotoxicity in mammalian cells. Therefore, we measured their concentrations in Shanghai drinking water and assessed their cytotoxicity, genotoxicity, and ability to transform NIH3T3 cells to tumorigenic lines. The concentrations of IAA and IF in Shanghai drinking water varied between summer and winter with maximum winter levels of 2.18 ?g/L IAA and 0.86 ?g/L IF. IAA with a lethal concentration 50 (LC50) of 2.77 ?M exhibited more potent cytotoxicity in NIH3T3 cells than IF (LC50 = 83.37 ?M). IAA, but not IF, induced a concentration-dependent DNA damage measured by ?-H2AX staining and increased tail moment in single-cell gel electrophoresis. Neither IAA nor IF increased micronucleus frequency. Prolonged exposure of NIH3T3 cells to IAA increased the frequencies of transformed cells with anchorage-independent growth and agglutination with concanavalin A. IAA-transformed cells formed aggressive fibrosarcomas after inoculation into Balb/c nude mice. This study demonstrated that IAA has a biological activity that is consistent with a carcinogen and human exposure should be of concern. PMID:23641915

Wei, Xiao; Wang, Shu; Zheng, Weiwei; Wang, Xia; Liu, Xiaolin; Jiang, Songhui; Pi, Jingbo; Zheng, Yuxin; He, Gengsheng; Qu, Weidong

2013-06-01

95

Transformation of hematopoietic cells by the Ski oncoprotein involves repression of retinoic acid receptor signaling.  

PubMed

The Ski oncogene has dramatic effects on the differentiation of several different cell types. It induces the differentiation of quail embryo cells into myoblasts and arrests the differentiation of chicken hematopoietic cells. The mechanism that Ski uses to carry out these disparate biological activities is unknown. However, we were struck by the similarity of these effects to those of certain members of the nuclear hormone receptor family. Both Ski and the thyroid hormone receptor-derived oncogene v-ErbA can arrest the differentiation of avian erythroblasts, and v-Ski-transformed avian multipotent progenitor cells resemble murine hematopoietic cells that express a dominant-negative form of the retinoic acid receptor, RARalpha. In this paper, we have tested the hypothesis that v-Ski and its cellular homologue c-Ski exert their effects by interfering with nuclear hormone receptor-induced transcription. We demonstrate that Ski associates with the RAR complex and can repress transcription from a retinoic acid response element. The physiological significance of this finding is demonstrated by the ability of high concentrations of a RARalpha-specific ligand to abolish v-Ski-induced transformation of the multipotent progenitors. These results strongly suggest that the ability of Ski to alter cell differentiation is caused in part by the modulation of RAR signaling pathways. PMID:9736711

Dahl, R; Kieslinger, M; Beug, H; Hayman, M J

1998-09-15

96

Monitoring of fatty acid composition in virgin olive oil by Fourier transformed infrared spectroscopy coupled with partial least squares  

Microsoft Academic Search

A rapid Fourier transformed infrared (FTIR) attenuated total reflectance (ATR) spectroscopic method was applied to the determination of fatty acid (FA) profile and peroxide value (PV) of virgin olive oil. Calibration models were constructed using partial least squares (PLS) regression. A FA calibration model was constructed in the spectral range from 3033 to 700cm?1. Oleic acid (62.0–80.0%), linoleic acid (5.3–15.0%),

Rubén M. Maggio; Teodoro S. Kaufman; Michele Del Carlo; Lorenzo Cerretani; Alessandra Bendini; Angelo Cichelli; Dario Compagnone

2009-01-01

97

All trans-retinoic acid (ATRA) induces re-differentiation of early transformed breast epithelial cells.  

PubMed

Retinoids have been used as potential chemotherapeutic or chemopreventive agents because of their differentiative, anti-proliferative, pro-apoptotic and antioxidant properties. We investigated the effect of all trans-retinoic acid (ATRA) at different stages of the neoplastic transformation using an in vitro model of breast cancer progression. This model was previously developed by treating the MCF-10F human normal breast epithelial cells with high dose of estradiol and consists of four cell lines which show a progressive neoplastic transformation: MCF-10F, normal stage; trMCF, transformed MCF-10F; bsMCF, invasive stage; and caMCF, tumorigenic stage. In 3D cultures, MCF-10F cells form tubules resembling the structures in the normal mammary gland. After treatment with estradiol, these cells formed tubules and spherical masses which are indicative of transformation. Cells that only formed spherical masses in collagen were isolated (trMCF clone 11) and treated with ATRA. After treatment with 10 or 1 µM ATRA, the trMCF clone 11 cells showed tubules in collagen; 10 and 43% of the structures were tubules in cells treated with 10 and 1 µM ATRA, respectively. Gene expression studies showed that 207 genes upregulated in transformed trMCF clone 11 cells were downregulated after 1 µM ATRA treatment to levels comparable to those found in the normal breast epithelial cells MCF-10F. Furthermore, 236 genes that were downregulated in trMCF clone 11 were upregulated after 1 µM ATRA treatment to similar levels shown in normal epithelial cells. These 443 genes defined a signature of the ATRA re-programming effect. Our results showed that 1 µM ATRA was able to re-differentiate transformed cells at early stages of the neoplastic process and antagonistically regulate breast cancer associated genes. The invasive and tumorigenic cells did not show any changes in morphology after ATRA treatment. These results suggest that ATRA could be used as a chemopreventive agent to inhibit the progression of premalignant lesions of the breast. PMID:24676586

Arisi, Maria F; Starker, Rebecca A; Addya, Sankar; Huang, Yong; Fernandez, Sandra V

2014-06-01

98

All trans-retinoic acid (ATRA) induces re-differentiation of early transformed breast epithelial cells  

PubMed Central

Retinoids have been used as potential chemotherapeutic or chemopreventive agents because of their differentiative, anti-proliferative, pro-apoptotic and antioxidant properties. We investigated the effect of all trans-retinoic acid (ATRA) at different stages of the neoplastic transformation using an in vitro model of breast cancer progression. This model was previously developed by treating the MCF-10F human normal breast epithelial cells with high dose of estradiol and consists of four cell lines which show a progressive neoplastic transformation: MCF-10F, normal stage; trMCF, transformed MCF-10F; bsMCF, invasive stage; and caMCF, tumorigenic stage. In 3D cultures, MCF-10F cells form tubules resembling the structures in the normal mammary gland. After treatment with estradiol, these cells formed tubules and spherical masses which are indicative of transformation. Cells that only formed spherical masses in collagen were isolated (trMCF clone 11) and treated with ATRA. After treatment with 10 or 1 ?M ATRA, the trMCF clone 11 cells showed tubules in collagen; 10 and 43% of the structures were tubules in cells treated with 10 and 1 ?M ATRA, respectively. Gene expression studies showed that 207 genes upregulated in transformed trMCF clone 11 cells were downregulated after 1 ?M ATRA treatment to levels comparable to those found in the normal breast epithelial cells MCF-10F. Furthermore, 236 genes that were downregulated in trMCF clone 11 were upregulated after 1 ?M ATRA treatment to similar levels shown in normal epithelial cells. These 443 genes defined a signature of the ATRA re-programming effect. Our results showed that 1 ?M ATRA was able to re-differentiate transformed cells at early stages of the neoplastic process and antagonistically regulate breast cancer associated genes. The invasive and tumorigenic cells did not show any changes in morphology after ATRA treatment. These results suggest that ATRA could be used as a chemopreventive agent to inhibit the progression of premalignant lesions of the breast.

ARISI, MARIA F.; STARKER, REBECCA A.; ADDYA, SANKAR; HUANG, YONG; FERNANDEZ, SANDRA V.

2014-01-01

99

Radiation-induced neoplastic transformation of C3H10T1/2 cells is suppressed by ascorbic acid  

SciTech Connect

X-ray induced transformation of C3H10T1/2 cells was suppressed in a concentration-dependent manner by administration of ascorbic acid after irradiation (0.1-20 micrograms/ml for the first week) in the culture medium. The dose-response curve was shifted about 60% downward and was slightly steeper in the presence of ascorbic acid (5 micrograms/ml for the first week) than in its absence. The 1-week treatment procedure revealed that cells initiated by radiation remained susceptible to ascorbic acid until the time of morphological phenotype expression. The neoplastically transformed phenotype expressed after incubation for 8 weeks could no longer be suppressed by ascorbic acid even after culture transfer. Similarly, the neoplastically transformed phenotype suppressed for 8 weeks by ascorbic acid treatment was not subsequently expressed in the absence of ascorbic acid. On the basis of the oxygen-detoxifying nature of ascorbic acid, we postulated that expression of the neoplastically transformed phenotype is promoted by reactive oxygen species and peroxy radicals generated in cells during the whole assay period. The data may be useful as a guide for chemopreventive efforts against radiation carcinogenesis.

Yasukawa, M.; Terasima, T.; Seki, M. (National Institute of Radiological Sciences, Chiba (Japan))

1989-12-01

100

Fourier transform infrared spectroscopic imaging parameters describing acid phosphate substitution in biologic hydroxyapatite.  

PubMed

Acid phosphate substitution into mineralized tissues is an important determinant of their mechanical properties and their response to treatment. This study identifies and validates Fourier transform infrared spectroscopic imaging (FTIRI) spectral parameters that provide information on the acid phosphate (HPO4) substitution into hydroxyapatite in developing mineralized tissues. Curve fitting and Fourier self-deconvolution were used to identify subband positions in model compounds (with and without HPO4). The intensity of subbands at 1127 and 1110 cm(-1) correlated with the acid phosphate content in these models. Peak height ratios of these subbands to the ?3 vibration at 1096 cm(-1) found in stoichiometric apatite were evaluated in the model compounds and mixtures thereof. FTIRI spectra of bones and teeth at different developmental ages were analyzed using these spectral parameters. Factor analysis (a chemometric technique) was also conducted on the tissue samples and resulted in factor loadings with spectral features corresponding to the HPO4 vibrations described above. Images of both factor correlation coefficients and the peak height ratios 1127/1096 and 1112/1096 cm(-1) demonstrated higher acid phosphate content in younger vs. more mature regions in the same specimen. Maps of the distribution of acid phosphate content will be useful for characterizing the extent of new bone formation, the areas of potential decreased strength, and the effects of therapies such as those used in metabolic bone diseases (osteoporosis, chronic kidney disease) on mineral composition. Because of the wider range of values obtained with the 1127/1096 cm(-1) parameter compared to the 1110/1096 cm(-1) parameter and the smaller scatter in the slope, it is suggested that this ratio should be the parameter of choice. PMID:23380987

Spevak, Lyudmila; Flach, Carol R; Hunter, Tracey; Mendelsohn, Richard; Boskey, Adele

2013-05-01

101

A Rare Phaeodactylum tricornutum Cruciform Morphotype: Culture Conditions, Transformation and Unique Fatty Acid Characteristics.  

PubMed

A rare Phaeodactylum tricornutum cruciform morphotype was obtained and stabilized with a proportion of more than 31.3% in L1 medium and is reported for the first time. Long-term culture and observation showed that the cruciform morphotype was capable of transforming to the oval form following the degeneration of arms by two processes. After three months of culture, four morphotypes existed in a relatively stable proportion in culture for six months (10.5% for oval, 11.3% for fusiform, 37.2% for triradiate and 41.0% for cruciform). Low temperature was particularly beneficial for cruciform cell formation. As the culture temperature decreased from 25°C to 10°C, the percentage of the cruciform morphotype increased from 39.1% to 55.3% approximately. The abundant cruciform cells endowed this strain with unique fatty acid characteristics. The strain cultured at 15°C showed both maximum content of neutral lipid in a single cell and total yield. The maximum content of fatty acid methyl esters was C16:1 for Phaeodactylum tricornutum cultured at four temperatures (43.82% to 50.82%), followed by C16:0 (20.47% to 22.65%). Unique fatty acid composition endowed this strain with excellent quality for biodiesel production. PMID:24710200

He, Liyan; Han, Xiaotian; Yu, Zhiming

2014-01-01

102

A Rare Phaeodactylum tricornutum Cruciform Morphotype: Culture Conditions, Transformation and Unique Fatty Acid Characteristics  

PubMed Central

A rare Phaeodactylum tricornutum cruciform morphotype was obtained and stabilized with a proportion of more than 31.3% in L1 medium and is reported for the first time. Long-term culture and observation showed that the cruciform morphotype was capable of transforming to the oval form following the degeneration of arms by two processes. After three months of culture, four morphotypes existed in a relatively stable proportion in culture for six months (10.5% for oval, 11.3% for fusiform, 37.2% for triradiate and 41.0% for cruciform). Low temperature was particularly beneficial for cruciform cell formation. As the culture temperature decreased from 25°C to 10°C, the percentage of the cruciform morphotype increased from 39.1% to 55.3% approximately. The abundant cruciform cells endowed this strain with unique fatty acid characteristics. The strain cultured at 15°C showed both maximum content of neutral lipid in a single cell and total yield. The maximum content of fatty acid methyl esters was C16:1 for Phaeodactylum tricornutum cultured at four temperatures (43.82% to 50.82%), followed by C16:0 (20.47% to 22.65%). Unique fatty acid composition endowed this strain with excellent quality for biodiesel production.

He, Liyan; Han, Xiaotian; Yu, Zhiming

2014-01-01

103

Transforming growth factor beta2 is negatively regulated by endogenous retinoic acid during early heart morphogenesis.  

PubMed

Vitamin A-deficient (VAD) quail embryos lack the vitamin A-active form, retinoic acid (RA) and are characterized by a phenotype that includes a grossly abnormal cardiovascular system that can be rescued by RA. Here we report that the transforming growth factor, TGFbeta2 is involved in RA-regulated cardiovascular development. In VAD embryos TGFbeta2 mRNA and protein expression are greatly elevated. The expression of TGFbeta receptor II is also elevated in VAD embryos but is normalized by treatment with TGFbeta2-specific antisense oligonucleotides (AS). Administration of this AS or an antibody specific for TGFbeta2 to VAD embryos normalizes posterior heart development and vascularization, while the administration of exogenous active TGFbeta2 protein to normal quail embryos mimics the excessive TGFbeta2 status of VAD embryos and induces VAD cardiovascular phenotype. In VAD embryos pSmad2/3 and pErk1 are not activated, while pErk2 and pcRaf are elevated and pSmad1/5/8 is diminished. We conclude that in the early avian embryo TGFbeta2 has a major role in the retinoic acid-regulated posterior heart morphogenesis for which it does not use Smad2/3 pathways, but may use other signaling pathways. Importantly, we conclude that retinoic acid is a critical negative physiological regulator of the magnitude of TGFbeta2 signals during vertebrate heart formation. PMID:20507358

Ghatpande, Satish K; Zhou, Hui-Ren; Cakstina, Inese; Carlson, Christopher; Rondini, Elizabeth A; Romeih, Mahmoud; Zile, Maija H

2010-06-01

104

Spectral and polarimetric characterization of gazeous and telluric planets with SEE COAST  

NASA Astrophysics Data System (ADS)

SEE COAST stands for Super Earth Explorer - Coronagraphic Off-Axis Space Telescope. The concept was initially proposed to ESA for Cosmic Vision. None of the direct detection exoplanet proposals were selected in 2007 and we are now pursuing our efforts to consolidate the astrophysical program and the technical developments for the next call for proposal. The prime objective of SEE COAST is to contribute to the understanding of the formation and evolution of planetary systems. Exploring the diversity of these objects is therefore the main driver to define the instrumentation. In the next decade the improvement of radial velocity instruments and obviously temporal coverage will provide us with a large numbers of long period giants as well as telluric planets, namely Super Earths. Obtaining the spectral and polarimetric signatures of these objects in the visible range to measure atmospheric parameters (molecular composition, clouds, soils, …) will be unique and with important scientific returns. A space mission complementary to near IR instruments like SPHERE, GPI, JWST and later ELTs for the full characterization of giants and Super Earths is a first secure step towards the longer term goal that is the characterization of telluric planets with mass and atmosphere comparable to that of the Earth. An overview of the astrophysical motivation and the trade-off that lead to a simple integrated concept of a space-based high contrast imaging instrument are given here.

Boccaletti, A.; Baudoz, P.; Mawet, D.; Schneider, J.; Tinetti, G.; Galicher, R.; Stam, D.; Cavarroc, C.; Hough, J.; Doel, P.; Pinfield, D.; Keller, C.-U.; Beuzit, J.-L.; Udry, S.; Ferrari, A.; Martin, E.; Ménard, F.; Sein, E.

2011-07-01

105

The local structure of gadolinium-borate-tellurate vitroceramics investigated by FTIR and EPR spectroscopy  

NASA Astrophysics Data System (ADS)

The present study provides interesting information concerning devitrification behavior of xGd2O3·(100-x)[6TeO2·4B2O3] vitreous system with 0 <= x <= 30 mol%. The structural changes have been analyzed with increasing rare earth concentration. Two halos characteristic of the amorphous compounds can be observed in XRD diffraction pattern for sample with x >= 20 mol% Gd2O3. These changes can be explained only if we admit that the adding of gadolinium oxide now participate in the network as [GdOn] structural units yielding a change from the continuous borate-tellurate network to the continuous gadolinium-borate-tellurate network with interconnected through Gd-O-B and Gd-O-Te bridges. The EPR spectra of the studied glass ceramics reveal an increase of the content of Gd+3 ions in network former and modifier positions. Therefore, Gd+3 ions will coordinate more with non-bridging oxygens leading the decreased of the number of individual Gd+3 ions.

Rada, M.; Culea, E.; Rada, S.; Pascuta, P.; Culea, M.; Dan, V.; Rusu, T.; Maties, V.; Bratu, I.

2009-08-01

106

Studies on the transformation of rat embryo cells of low passage by carcinogenic fluorenylhydroxamic acids and their acetate esters.  

PubMed

Rat embryo cells of low passage subjected to a single treatment with certain carcinogenic fluorenylhydroxamic acids and their respective acetate esters showed signs of transformation in vitro, such as changes in phenotype, growth in soft agar and agglutination with concanavalin A. In addition, certain changes in karyotype and loss of diploidy were observed. There was no evidence, either by electron microscopy or by assay of RNA-dependent DNA polymerase, for the presence of virus. None of these cell lines produced tumors after inoculation into the isologous host. The results of these study lead us to suggest that malignant transformation is a multistep process and that certain criteria of transformation of rat embryo cells are associated with the initial stage(s) in which the cells are transformed without being tumorigenic. The ultimate test for malignant transformation of rat embryo cells remains the production of tumors in a susceptible host after inoculation of treated cells. PMID:566719

Kurzepa, H; Gutmann, H R; Malejka-Giganti, D; Cervenka, J; Vosika, G J; Rydell, R E

1978-03-01

107

Effect of Retinole Acid and Phorbol-12-myristate-13-acetate on Glycosyltransferase Activities in Normal and Transformed Cells1  

Microsoft Academic Search

Retinole acid was found to increase the activity of cytidine monophos- phosialic acid:lactosylceramide sialyltransferase activity in a nontrans- formed clonal hamster cell line, NIL 8, and a virally transformed clone, NIL 8-HSV. The potent tumor promoter phorbol-12-myristate-13-ace- tate (I'M A) had no significant effect on sialyltransferase activity in NIL 8 cells but stimulated this activity almost 6-fold when added to

Joseph R. Moskal; Michael W. Lockney; James E. Trosko; Charles C. Sweeley

1987-01-01

108

Glycochenodeoxycholic acid inhibits calcium phosphate precipitation in vitro by preventing the transformation of amorphous calcium phosphate to calcium hydroxyapatite.  

PubMed Central

Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally inhibited transformation of amorphous calcium phosphate microprecipitates to macroscopic crystalline calcium hydroxyapatite. This inhibition was not mediated by decreased Ca2+ activity. Taurocholic acid (2-12 mM) did not affect hydroxyapatite formation, but antagonized glycochenodeoxycholic acid. Both amorphous and crystalline precipitates contained a surface fraction relatively rich in phosphate. The surface phosphate content was diminish by increasing glycochenodeoxycholic acid concentrations, and this relationship was interpreted as competition between bile acid and HPO4(-4) for binding sites on the calcium phosphate surface. A phosphate-rich crystal surface was associated with rapid transition from amorphous to crystalline states. These results indicate that glycochenodeoxycholic acid prevents transformation of amorphous calcium phosphate to crystalline hydroxyapatite by competitively inhibiting the accumulation of phosphate on the crystal embryo surface.

Qiu, S M; Wen, G; Hirakawa, N; Soloway, R D; Hong, N K; Crowther, R S

1991-01-01

109

Structure-function evolution of the Transforming acidic coiled coil genes revealed by analysis of phylogenetically diverse organisms  

Microsoft Academic Search

BACKGROUND: Examination of ancient gene families can provide an insight into how the evolution of gene structure can relate to function. Functional homologs of the evolutionarily conserved transforming acidic coiled coil (TACC) gene family are present in organisms from yeast to man. However, correlations between functional interactions and the evolution of these proteins have yet to be determined. RESULTS: We

Ivan H Still; Ananthalakshmy K Vettaikkorumakankauv; Anthony DiMatteo; Ping Liang

2004-01-01

110

On the estimation of tidal and subinertial alongshore water transport from onshore telluric field measurements  

NASA Astrophysics Data System (ADS)

Onshore measurements of telluric field oscillations have been used to estimate the water transport associated to tidal flow in the western Portuguese coast. The onshore E-W dipoles located at São Jacinto and Sines were calibrated by comparing the ocean modelled N-S shelf water transport originated by the main lunar tidal frequency and the corresponding onshore motionally tidal electric field. Calibration factors of 3.00×104 and 4.25×103 m3 s-1 for each mV km-1, with motionally induced origin, were estimated for São Jacinto and Sines, respectively. The results showed that it is possible to estimate the water transport from onshore measurements. The possibility of estimate subinertial alongshelf flow was also assessed, concluding that due to the lack of periodicities controlling that flow is not possible to establish a relationship between alongshelf transports and measured electric potential difference.

Marta-Almeida, Martinho; Santos, Fernando; Dubert, Jesus; Nolasco, Rita; Bernardo, Ivo; Soares, Antonio; Peliz, Alvaro; Dias, Joao

2010-05-01

111

Seismic and magneto-telluric imaging for geothermal exploration at Jemez pueblo in New Mexico  

SciTech Connect

A shallow geothermal reservoir in the Pueblo of Jemez in New Mexico may indicate a commercial-scale geothermal energy potential in the area. To explore the geothermal resource at Jemez Pueblo, seismic surveys are conducted along three lines for the purpose of imaging complex subsurface structures near the Indian Springs fault zone. A 3-D magneto-telluric (MT) survey is also carried out in the same area. Seismic and MT imaging can provide complementary information to reveal detailed geologic formation properties around the fault zones. The high-resolution seismic images will be used together with MT images, geologic mapping, and hydrogeochemistry, to explore the geothermal resource at Jemez Pueblo, and to determine whether a conunercial-scale geothermal resource exists for power generation or direct use applications after drilling and well testing.

Huang, Lianjie [Los Alamos National Laboratory; Albrecht, Michael [LOS ALAMOS GEOTHERMAL

2011-01-25

112

Correlation of Solar Activities with the Telluric Currents Level in the Northern Region of Malaysia  

NASA Astrophysics Data System (ADS)

The relation between solar activities and the geomagnetic field induced currents (GIC) have been well studied in the auroral region and it usually occurs most frequently at high latitudes. However, during major geomagnetic storms, the auroral zone can extend substantially towards lower latitudes. Disturbance caused by solar activities can disrupt power grids and also increase the corrosion rate of buried natural gas pipelines. GIC are driven by the geomagnetic field induced by a geomagnetic disturbance. In this paper, we investigated the correlation between solar activities using the interplanetary magnetic field (IMF) and geomagnetic disturbance storm time (DST) index data with the telluric currents (also referred to as geomagnetic induced currents GIC) level through the disturbance pattern of geomagnetic field. The research areas are from Lunas in Kedah to Perlis. The pattern of geomagnetic field disturbance had been identified and analyzed to investigate the harmful effect of geomagnetic storms towards the performance of complex power grid in Malaysia.

Razelan, Mazlina M.; Said, N. Masdiana Md; Aziz, A. H. A.; Chong, H. Y.; Nawawi, M.

2010-07-01

113

A New Lithium Hydrogen Tellurate—LiH 5TeO 6  

NASA Astrophysics Data System (ADS)

X-ray structural analysis for lithium pentahydrogen tellurate has been carried out. The substance crystallizes in a tetragonal system in the space group P4 2/ n, a=7.6350(6), c=7.5014(9) Å, V=437.28(7) Å 3, Z=4, and R=0.0189 for 350 observed reflections. The crystal structure consists of isolated TeO 6 octahedra, which are connected by a network of hydrogen bonds. The lithium atoms are surrounded by slightly deformed oxygen octahedra. Infrared and Raman spectra have been studied. The FTIR spectra were recorded down to a temperature of 90 K. Thermal behavior of LiH 5TeO 6 has been studied by the methods of TG, DTA, DTG, and DSC. Conclusions following from the DSC and FTIR measurements exclude the existence of structural phase transitions in the temperature interval from 90 K to the temperature of decomposition of the compound (390 K).

Vanek, Ladislav; N?mec, Ivan; Císa?ová, Ivana; Mi?ka, Zden?k; Fajnor, Vladimír.

2000-03-01

114

(NH 4) 4P 4O 12 · 2Te(OH) 6 · 2H 2O, the first example of a tetrametaphosphate-tellurate  

NASA Astrophysics Data System (ADS)

Ammonium tetrametaphosphate-tellurate dihydrate, (NH 4) 4P 4O 12 · 2Te(OH) 6 · 2H 2O, is triclinic with the following unit cell dimensions: a = 11.845(6), b = 8.554(5), c = 7.433(5) Å, ? = 66.28(5), ? = 95.91(5), ? = 76.00(5)° space group: P overline1 and Z = 1. The crystal structure has been determined with a final R value of 0.021. As in the previously described phosphate-tellurates, monophosphate-tellurate and trimetaphosphate-tellurates, the phosphoric anion (here the P 4O 12 ring) is independent of the octahedral Te(OH) 6 group. A complete pattern of the hydrogen bonds is given.

Durif, A.; Averbuch-Pouchot, M. T.; Guitel, J. C.

1982-02-01

115

Chemistry of fog waters in California's Central Valley: 2. Photochemical transformations of amino acids and alkyl amines  

NASA Astrophysics Data System (ADS)

Although amino compounds are seemingly ubiquitous in atmospheric particles and deposition, little is known of their fate in the troposphere. We report here on the fate of 21 amino acids and alkyl amines in fog waters from Davis, California, illuminated with simulated sunlight or monochromatic light. In all experiments four amino acids - histidine (His), methionine (Met), tryptophan (Trp), and tyrosine (Tyr) - consistently decayed, with half-lives that ranged from ˜1 h (Met) to ˜23 h (Tyr) in midday, winter-solstice sunlight at Davis, CA ( solar zenith angle =62°) . Half-lives for the remaining amino compounds examined were typically >45 h in our experiments. Reactions with photoformed hydroxyl radical ( ·OH) and singlet molecular oxygen (O 2( 1? g) or 1O2?) accounted for essentially all of the loss of His and Tyr, the less reactive of the four amino acids that consistently decayed, but were minor sinks for the more reactive compounds (Met and Trp). Additional experiments revealed that methionine sulfoxide (MetSO) was formed with a yield of 58-88% during the oxidation of methionine, suggesting that the ratio of MetSO to Met might be a useful chemical marker for the age of atmospheric particles and drops. Other products expected from the transformation of amino compounds include ammonia, organic acids, and possibly mutagenic nitrosoaromatics. To complement our laboratory experiments, we also calculated rates of transformations of amino acids in near-neutral pH fog drops under ambient conditions. These calculations reveal that ozone should be a major sink for amino acids and that half-lives for many amino acids in ambient fog drops will be much shorter than those determined in our photochemistry experiments. Overall, our results indicate that reactions in atmospheric condensed phases will transform amino nitrogen compounds (including free amino acids as well as proteins and peptides) and, consequently, increase the bioavailability of nitrogen in atmospheric deposition.

McGregor, Keith G.; Anastasio, Cort

116

Disruption of the transforming growth factor-? pathway by tolfenamic acid via the ERK MAP kinase pathway.  

PubMed

Transforming growth factor-? (TGF-?) modulates diverse cell physiological processes and plays a complicated role in tumor development. It has been well established that TGF-? inhibits cell proliferation in normal and early stage carcinoma and facilitates tumor metastasis in late-stage carcinoma. Therefore, blocking TGF-? signaling in advanced stage carcinogenesis provides a potentially interesting chemotherapeutic strategy. We aimed to determine the effect of tolfenamic acid (TA) on TGF-?-induced protumorigenic activity. Here, we demonstrate that TA attenuates tumor-promoting effects of TGF-? in cancer cells. Further observation indicates TA blocks the TGF-?/Smad pathway, and this blockage is mainly attributed to the interference of TGF-?1-driven phosphorylation of Smad2/3. We also show that TA could exert this effect on cancer cell lines from several different origins and that TA is much better than other non-steroidal anti-inflammatory drugs with respect to inhibition of TGF-?1-induced Smad2 phosphorylation. Finally, extracellular signal-regulated kinase mitogen-activated protein kinase plays a role in TA-induced suppression of Smad2/3 phosphorylation and subsequent nuclear accumulation of Smad2/3 in response to TGF-?1. Our study provides a possible mechanism by which TA affects anticancer activity by inhibiting the TGF-? pathway and sheds light on the application of TA for cancer patients. PMID:23864386

Zhang, Xiaobo; Min, Kyung-Won; Liggett, Jason; Baek, Seung Joon

2013-12-01

117

Effect of a sulfonated azo dye and sulfanilic acid on nitrogen transformation processes in soil.  

PubMed

Introduction of organic dyes into soil via wastewater and sludge applications has been of increasing concern especially in developing or under-developed countries where appropriate management strategies are scarce. Assessing the response of terrestrial ecosystems to organic dyes and estimating the inhibition concentrations will probably contribute to soil remediation studies in regions affected by the same problem. Hence, an incubation study was conducted in order to investigate the impact of a sulfonated azo dye, Reactive Black 5 (RB5) and sulfanilic acid (SA), a typical representative of aromatic sulfonated amines, on soil nitrogen transformation processes. The results apparently showed that nitrogen related processes in soil can be used as bioindicators of anthropogenic stress caused by organic dyes. It was found that urease activity, arginine ammonification rate, nitrification potential and ammonium oxidising bacteria numbers decreased by 10-20% and 7-28% in the presence of RB5 (> 20 mg/kg dry soil) and SA (> 8 mg/kg dry soil), respectively. Accordingly, it was concluded that organic dye pollution may restrict the nitrogen-use-efficiency of plants, thus further reducing the productivity of terrestrial ecosystems. Furthermore, the response of soil microbiota to SA suggested that inhibition effects of the organic dye may continue after the possible reduction of the parent dye to associated aromatic amines. PMID:19524359

Topaç, F Olcay; Dindar, Efsun; Uçaro?lu, Selnur; Ba?kaya, Hüseyin S

2009-10-30

118

Fitness Landscape Transformation through a Single Amino Acid Change in the Rho Terminator  

PubMed Central

Regulatory networks allow organisms to match adaptive behavior to the complex and dynamic contingencies of their native habitats. Upon a sudden transition to a novel environment, the mismatch between the native behavior and the new niche provides selective pressure for adaptive evolution through mutations in elements that control gene expression. In the case of core components of cellular regulation and metabolism, with broad control over diverse biological processes, such mutations may have substantial pleiotropic consequences. Through extensive phenotypic analyses, we have characterized the systems-level consequences of one such mutation (rho*) in the global transcriptional terminator Rho of Escherichia coli. We find that a single amino acid change in Rho results in a massive change in the fitness landscape of the cell, with widely discrepant fitness consequences of identical single locus perturbations in rho* versus rhoWT backgrounds. Our observations reveal the extent to which a single regulatory mutation can transform the entire fitness landscape of the cell, causing a massive change in the interpretation of individual mutations and altering the evolutionary trajectories which may be accessible to a bacterial population.

Tavazoie, Saeed

2012-01-01

119

Caffeic acid phenethyl ester (CAPE) prevents transformation of human cells by arsenite (As) and suppresses growth of As-transformed cells.  

PubMed

Recent evidence suggests that inflammatory cytokines and growth factors contribute to arsenite (As)-induced human carcinogenesis. We investigated the expression of inflammatory cytokine mRNAs during the transformation process induced by chronic As exposure in non-tumorigenic human osteogenic sarcoma (N-HOS) cells using gene arrays, and results were confirmed by RT-PCR and protein arrays. Caffeic acid phenethyl ester (CAPE), a naturally occurring immunomodulating agent, was used to evaluate the role of inflammatory factors in the process of As-mediated N-HOS cell transformation and in As-transformed HOS (AsT-HOS) cells. We found that an 8-week continuous exposure of N-HOS to 0.3 microM arsenite resulted in HOS cell transformation. That exposure also caused substantial decreases in inflammatory cytokine mRNAs, such as interleukin (IL) IL-1alpha, IL-2, IL-8, IL-18, MCP-1, TGF-beta2, and TNF-alpha, while it increased c-jun mRNA in a time-dependent manner. Co-incubation of N-HOS with As and CAPE (0.5-2.5 microM) prevented As-mediated declines in cytokine mRNAs in the co-treated cells, as well as their transformation to anchorage independence, while it caused decreases in c-jun mRNA. CAPE (up to 10 microM) had no effect on growth of N-HOS cells. However, CAPE (1-10 microM) treatment of AsT-HOS cells inhibited cell growth, induced cell cycle G2/M arrest, and triggered apoptosis, accompanied by changes in cytokine gene expression, as well as decreases in cyclin B1 and cdc2 abundance. Resveratrol (RV) and (-)(.) epigallocatechin gallate (EGCG), preventive agents present in grapes and green tea, respectively, induced similar changes in AsT-HOS cell growth but required much higher doses than CAPE to cause 50% growth arrest (<2.5 microM CAPE versus 25 microM RV or 50 microM EGCG). Overall, our findings suggest that inflammatory cytokines play an important role in the suppressive effects of CAPE on As-induced cell transformation and in the selective cytotoxicity of CAPE to As-transformed HOS cells. PMID:16085347

Yang, Chengfeng; Wu, Jing; Zhang, Ronghe; Zhang, Ping; Eckard, Jonathan; Yusuf, Rita; Huang, Xi; Rossman, Toby G; Frenkel, Krystyna

2005-09-15

120

Gene Expression of the Lysophosphatidic Acid Receptor 1 Is a Target of Transforming Growth Factor Beta  

PubMed Central

The lysophosphatidic acid (LPA) receptor LPA1/Edg2 is the first identified LPA receptor. Although its wide tissue distribution and biological functions have been well studied, little is known about how LPA1 is transcriptionally regulated. In the current study, we showed that LPA1 is a physiological target of transforming growth factor beta (TGF?)-mediated repression. In both normal and neoplastic cells, TGF? inhibits LPA1 promoter activity, LPA1 mRNA expression, and LPA1-dependent chemotaxis and tumor cell invasion. Knockdown of the TGF? intracellular effector Smad3 or Smad4 with lentivirally transduced shRNA relieved these inhibitory effects of TGF?. Interestingly, the LPA1 promoter contains two potential TGF? inhibitory elements (TIEs), each consisting of a Smad binding site and an adjacent E2F4/5 element, structurally similar to the TIE found on the promoter of the well-defined TGF? target gene c-myc. Deletion and point mutation analyses indicate that the distal TIE located at 401 bp from the transcription initiation site, is required for TGF? repression of the LPA1 promoter. A DNA pull-down assay showed that the -401 TIE was capable of binding Samd3 and E2F4 in TGF?-treated cells. TGF?-induced binding of the Smad complex to the native -401 TIE sequence of the LPA1 gene promoter was further verified by chromatin immunoprecipitation assays. We therefore identified a novel role of TGF? in the control of LPA1 expression and LPA1-coupled biological functions, adding LPA1 to the list of TGF?-repressed target genes.

Wu, Jinhua; Mukherjee, Abir; Lebman, Deborah A; Fang, Xianjun

2012-01-01

121

Valproic acid overcomes transforming growth factor-?-mediated sorafenib resistance in hepatocellular carcinoma.  

PubMed

Sorafenib is a multi-kinase inhibitor approved for hepatocellular carcinoma, but rarely causes tumor regression in patients with chronic liver diseases. To investigate whether growth factor-mediated signaling is involved in sorafenib resistance, HepG2 and PLC/PRF/5 hepatoma cells were exposed to epidermal growth factor (EGF), hepatocyte growth factor (HGF) or transforming growth factor-? (TGF-?) prior to treatment with sorafenib. Furthermore, to identify an effective combination treatment with sorafenib, growth factor-sensitized cells were treated with sorafenib alone or in combination with celecoxib, lovastatin or valproic acid (VPA). Trypan blue staining and Annexin V assays showed that the cytotoxic effect of sorafenib was inhibited by 15-54% in cells sensitized to TGF-? (P<0.05). Western blotting analysis showed that TGF-? significantly activated extracellular signal-regulated kinase (ERK)-mediated AKT signaling, and sorafenib failed to suppress both ERK and AKT in TGF-?-sensitized cells. The decreased anti-tumor effect of sorafenib was rescued by chemical inhibition of ERK and AKT. When TGF-?-sensitized cells were treated with sorafenib plus VPA, the levels of phosphorylated ERK and AKT were considerably suppressed and the numbers of dead cells were increased by 3.7-5.7-fold compared with those exposed to sorafenib alone (P<0.05). Moreover, low dose sorafenib-induced cell migration was effectively suppressed by combination treatment with sorafenib and VPA. Collectively, TGF-?/ERK/AKT signaling might play a critical role in sorafenib resistance in hepatoma cells, and combination treatment with VPA may be effective against this drug resistance. PMID:24817927

Matsuda, Yasunobu; Wakai, Toshifumi; Kubota, Masayuki; Osawa, Mami; Hirose, Yuki; Sakata, Jun; Kobayashi, Takashi; Fujimaki, Shun; Takamura, Masaaki; Yamagiwa, Satoshi; Aoyagi, Yutaka

2014-01-01

122

Gene expression of the lysophosphatidic acid receptor 1 is a target of transforming growth factor beta.  

PubMed

The lysophosphatidic acid (LPA) receptor LPA1/Edg2 is the first identified LPA receptor. Although its wide tissue distribution and biological functions have been well studied, little is known about how LPA1 is transcriptionally regulated. In the current study, we showed that LPA1 is a physiological target of transforming growth factor beta (TGF?)-mediated repression. In both normal and neoplastic cells, TGF? inhibits LPA1 promoter activity, LPA1 mRNA expression and LPA1-dependent chemotaxis and tumor cell invasion. Knockdown of the TGF? intracellular effector Smad3 or Smad4 with lentivirally transduced short hairpin RNA relieved these inhibitory effects of TGF?. Interestingly, the LPA1 promoter contains two potential TGF? inhibitory elements (TIEs), each consisting of a Smad-binding site and an adjacent E2F4/5 element, structurally similar to the TIE found on the promoter of the well-defined TGF? target gene c-myc. Deletion and point mutation analyses indicate that the distal TIE located at 401?bp from the transcription initiation site, is required for TGF? repression of the LPA1 promoter. A DNA pull-down assay showed that the -401 TIE was capable of binding Samd3 and E2F4 in TGF?-treated cells. TGF?-induced binding of the Smad complex to the native -401 TIE sequence of the LPA1 gene promoter was further verified by chromatin immunoprecipitation assays. We therefore identified a novel role of TGF? in the control of LPA1 expression and LPA1-coupled biological functions, adding LPA1 to the list of TGF?-repressed target genes. PMID:22824789

Wu, J; Mukherjee, A; Lebman, D A; Fang, X

2013-06-27

123

Valproic acid overcomes transforming growth factor-?-mediated sorafenib resistance in hepatocellular carcinoma  

PubMed Central

Sorafenib is a multi-kinase inhibitor approved for hepatocellular carcinoma, but rarely causes tumor regression in patients with chronic liver diseases. To investigate whether growth factor-mediated signaling is involved in sorafenib resistance, HepG2 and PLC/PRF/5 hepatoma cells were exposed to epidermal growth factor (EGF), hepatocyte growth factor (HGF) or transforming growth factor-? (TGF-?) prior to treatment with sorafenib. Furthermore, to identify an effective combination treatment with sorafenib, growth factor-sensitized cells were treated with sorafenib alone or in combination with celecoxib, lovastatin or valproic acid (VPA). Trypan blue staining and Annexin V assays showed that the cytotoxic effect of sorafenib was inhibited by 15-54% in cells sensitized to TGF-? (P<0.05). Western blotting analysis showed that TGF-? significantly activated extracellular signal-regulated kinase (ERK)-mediated AKT signaling, and sorafenib failed to suppress both ERK and AKT in TGF-?-sensitized cells. The decreased anti-tumor effect of sorafenib was rescued by chemical inhibition of ERK and AKT. When TGF-?-sensitized cells were treated with sorafenib plus VPA, the levels of phosphorylated ERK and AKT were considerably suppressed and the numbers of dead cells were increased by 3.7-5.7-fold compared with those exposed to sorafenib alone (P<0.05). Moreover, low dose sorafenib-induced cell migration was effectively suppressed by combination treatment with sorafenib and VPA. Collectively, TGF-?/ERK/AKT signaling might play a critical role in sorafenib resistance in hepatoma cells, and combination treatment with VPA may be effective against this drug resistance.

Matsuda, Yasunobu; Wakai, Toshifumi; Kubota, Masayuki; Osawa, Mami; Hirose, Yuki; Sakata, Jun; Kobayashi, Takashi; Fujimaki, Shun; Takamura, Masaaki; Yamagiwa, Satoshi; Aoyagi, Yutaka

2014-01-01

124

Differences between the Ribonucleic Acids of Transforming and Nontransforming Avian Tumor Viruses*  

PubMed Central

The 60-70S RNAs of several transforming and nontransforming avian tumor viruses have different electrophoretic mobilities. The RNA of transforming viruses contains two electrophoretically separable subunit classes: a and b. The relative concentrations of these subunits vary with the virus strain. Avian leukosis viruses and nontransforming derivatives of a sarcoma virus lack subunits of class a. It is suggested that the presence of the class a subunit is related to the transforming ability for fibroblasts of the virus.

Duesberg, Peter H.; Vogt, Peter K.

1970-01-01

125

Anaerobic Respiration on Tellurate and Other Metalloids in Bacteria from Hydrothermal Vent Fields in the Eastern Pacific Ocean  

PubMed Central

This paper reports the discovery of anaerobic respiration on tellurate by bacteria isolated from deep ocean (1,543 to 1,791 m) hydrothermal vent worms. The first evidence for selenite- and vanadate-respiring bacteria from deep ocean hydrothermal vents is also presented. Enumeration of the anaerobic metal(loid)-resistant microbial community associated with hydrothermal vent animals indicates that a greater proportion of the bacterial community associated with certain vent fauna resists and reduces metal(loid)s anaerobically than aerobically, suggesting that anaerobic metal(loid) respiration might be an important process in bacteria that are symbiotic with vent fauna. Isolates from Axial Volcano and Explorer Ridge were tested for their ability to reduce tellurate, selenite, metavanadate, or orthovanadate in the absence of alternate electron acceptors. In the presence of metal(loid)s, strains showed an ability to grow and produce ATP, whereas in the absence of metal(loid)s, no growth or ATP production was observed. The protonophore carbonyl cyanide m-chlorophenylhydrazone depressed metal(loid) reduction. Anaerobic tellurate respiration will be a significant component in describing biogeochemical cycling of Te at hydrothermal vents.

Csotonyi, Julius T.; Stackebrandt, Erko; Yurkov, Vladimir

2006-01-01

126

Complexation of uranium(VI) with protocatechuic acid—application of iterative transformation factor analysis to EXAFS spectroscopy  

Microsoft Academic Search

.  The speciation of 1 mM uranium(VI) in carbonate-free aqueous solutions of 50 mM protocatechuic acid (PCA, 3,4-dihydroxybenzoic acid) was studied in the pH range of 4.0 to 6.8 using EXAFS spectroscopy. The uranium LIII-edge EXAFS spectra were analyzed using a newly developed computer algorithm for iterative transformation factor analysis (FA). Two structural different uranium(VI) complexes were observed. The speciation in the pH

A. Roßberg; T. Reich; G. Bernhard

2003-01-01

127

Transformation of salvianolic Acid B to salvianolic Acid a in aqueous solution and the in vitro liver protective effect of the main products.  

PubMed

Salvianolic acid A (Sal A) was considered to be the compound with highest activity in Salvia miltiorrhiza (danshen). Due to its low content in raw materials, many studies reported its preparation from salvianolic acid B (Sal B). However, the process of this transformation is still unknown. Our objective was to find the chemical change of the transformation from Sal B to Sal A. The results showed that Sal B was hydrolyzed to lithospermic acid (LA) first, and the latter was transformed into Sal A in thermal aqueous solution. The radical scavenging ability of Sal A, Sal B, and LA was tested through DPPH, and Sal A showed higher radical elimination ability compared to Sal B and LA. In vitro liver damage was induced by CCl4 in human hepatic WRL68 cell line. Sal A, Sal B, and LA showed liver protective ability in a dose-dependent manner, while Sal A possessed a much higher ability compared to Sal B and LA. PMID:24689808

Kan, Shidong; Chen, Zhouzhou; Shao, Lei; Li, Ji'an

2014-04-01

128

Studies on the transformation of rat embryo cells of low passage by carcinogenic fluorenylhydroxamic acids and their acetate esters  

Microsoft Academic Search

Summary  Rat embryo cells of low passage subjected to a single treatment with certain carcinogenic fluorenylhydroxamic acids and their\\u000a respective acetate esters showed signs of transformation in vitro, such as changes in phenotype, growth in soft agar and agglutination\\u000a with concanavalin. A. In addition, certain changes in karyotype and loss of diploidy were observed. There was no evidence,\\u000a either by electron

H. Kurzepa; H. R. Gutmann; D. Malejka-Giganti; A. Krauss; J. Cervenka; G. J. Vosika; R. E. Rydell

1978-01-01

129

Gas chromatography-fourier transform infrared spectrometry of fatty acids: New applications with a direct deposition interface  

Microsoft Academic Search

Infrared spectroscopy is a suitable spectroscopic method to differentiate geometric Z and E isomers of unsaturated compounds. A direct-deposition Fourier transform infrared spectrometer (FTIR), coupled to a gas chromatograph,\\u000a was used successfully to analyze with a high sensitivity traces of C18:1 fatty acid methyl ester (FAME) isomers. It could\\u000a also conclusively distinguish between isomers of conjugated diunsaturated FAME. The achievable

E. Sémon; S. Ferary; J. Auger; J. L. Le Quéré

1998-01-01

130

Trans Retinoic Acid Enhances the Growth Response of Epidermal Keratinocytes to Epidermal Growth Factor and Transforming Growth Factor Beta  

Microsoft Academic Search

Retinoids have been shown to either stimulate or inhibit epidermal keratinocyte proliferation. We have observed that in serum and growth factor free medium (basal medium), epidermal growth factor (EGF) and transforming growth factor alpha (TGF?) stimulated DNA synthesis in mouse epidermal keratinocyte cultures (mKC) in a time- and dose-dependent manner. Incubation with all-trans retinoic acid (RA) greatly enhanced the stimulatory

Philip S. Tong; Nancy N. Horowitz; Larry A. Wheeler

1990-01-01

131

Multivariate calibration of fourier transform infrared spectra for determining thiobarbituric acid-reactive substance content in palm oil  

Microsoft Academic Search

Fourier transform infrared (FTIR) spectra of palm oil samples between 2900 and 2800 cm?1 and 1800 and 1600 cm?1 were used to compare different multivariate calibration techniques for quantitative determination of their thiobarbituric\\u000a acid-reactive substance (TBARS) content. Fifty spectra (in duplicate) of palm oil with TBARS values between 0 and 0.25 were\\u000a used to calibrate models based on partial least

M. E. S. Mirghani; Y. B. Che Man; S. Jinap; B. S. Baharin; J. Bakar

2001-01-01

132

Deoxyribonucleic acid-mediated gene transfer in mammalian cells: molecular analysis of unstable transformants and their progression to stability.  

PubMed Central

To elucidate mechanisms involved in deoxyribonucleic acid-mediated gene transfer, we transferred the herpes simplex virus thymidine kinase gene (TK) into mouse Ltk- cells. Independent TK+ clones (transformants) and derivatives of each were tested for phenotypic expression and the presence and arrangement of TK sequences. Initially, transformants expressed viral TK unstable, with 10% of the cells in each generation losing both the TK+ phenotype and virally derived TK sequences. After a prolonged period in culture, stable subpopulations arose from which the TK+ phenotype and viral sequences were no longer lost at detectable frequency. Analysis of unstable cell populations indicated that individual viral deoxyribonucleic acid molecules were reduced in size, but were linked to other deoxyribonucleic acid to form molecules large enough to be precipitated in a Hirt fractionation. We term these molecules transgenomes. Analysis of independent unstable subclones derived from the primary transformants demonstrated that individual transgenomes could contain multiple copies of the viral TK sequences. Recipient cell lines frequently possessed more than one type of transgenome and possibly multiple copies per cell of each type. Stable derivatives possessed only one of the transgenomes present in the unstable parent, and these sequences were associated with a recipient cell chromosome. Images

Scangos, G A; Huttner, K M; Juricek, D K; Ruddle, F H

1981-01-01

133

State of the art of Lewis acid-containing zeolites: lessons from fine chemistry to new biomass transformation processes.  

PubMed

The former synthesis of TS-1 opened new catalytic opportunities for zeolites, especially for their application as selective redox catalysts in several fine chemistry processes. Interestingly, isolated Ti species in the framework positions of hydrophobic zeolites, such as high silica zeolites, offer unique Lewis acid sites even in the presence of protic polar solvents (such as water). Following this discovery, other transition metals (such as Sn, Zr, V, Nb, among others) have been introduced in the framework positions of different hydrophobic zeolitic structures, allowing their application in new fine chemistry processes as very active and selective redox catalysts. Recently, these hydrophobic metallozeolites have been successfully applied as efficient catalysts for several biomass-transformation processes in bulk water. The acquired knowledge from the former catalytic descriptions in fine chemistry processes using hydrophobic Lewis acid-containing zeolites has been essential for their application in these novel biomass transformations. In the present review, I will describe the recent advances in the synthesis of new transition metal-containing zeolites presenting Lewis acid character, and their unique catalytic applications in both fine chemistry and novel biomass-transformations. PMID:24142026

Moliner, Manuel

2014-03-21

134

Gene expression changes in BALB/3T3 transformants induced by poly(L-lactic acid) or polyurethane films.  

PubMed

We performed DNA microarray analysis on two BALB/3T3 transformants (A5 and A6) induced by polyurethane (PU) film, two (L11 and L21) induced by biodegradable poly(L-lactic acid) (PLLA) film, and the parental cells. The transforming ability of the cells was in the order A5 < A6 < L21 < L11. In all, 1176 cancer-related genes were up- or down-regulated in at least one transformant. Those that were markedly up-regulated were c-fos protooncogene, FBJ osteosarcoma oncogene B, and Jun oncogene; those markedly down-regulated were pleiotrophin, histidine triad nucleotide-binding protein, protein kinase C iota, and large multifunctional protease 7. A common function of proteins encoded by genes that underwent marked expression changes was bone formation. The genes were c-fos, FBJ osteosarcoma, Jun, pleiotrophin, a disintegrin-like and metalloprotease with TS-1 motif protein 1. This finding was consistent with the tumor formation in the 2-year PLLA or PU subcutaneous implantation into rats. The number of genes that underwent marked expression change in each transformant was consistent with its malignancy. PLLA induced more malignant transformants than PU, especially in relation to osteosarcoma-like gene expression. PMID:14704980

Matsuoka, Atsuko; Tsuchiya, Toshie

2004-02-01

135

Amino acid-dependent transformations of citrate-coated silver nanoparticles: Impact on morphology, stability and toxicity.  

PubMed

Humans face the risk of exposure to silver nanoparticles (AgNPs) due to their extensive application in consumer products. AgNPs can interact with many substances in the human body due to their chemically unstable nature and high activity properties, which might result in unknown hazards and even some serious diseases for humans. As the basic constituent element of human bodies, amino acids (AAs) differ in concentration and variety in different cells and tissues. Thus, understanding the transformation of citrate-coated AgNPs in the presence of AAs is crucial for determining their fate and toxicity in the human body. Our study focused on the transformation of the morphology, dissolution behavior and reaction product of AgNPs in different AA-containing systems and then evaluated the effect of these transformations on the cytotoxicity of AgNPs. The obtained results indicated that the addition of glycine with the lowest Ag(+) binding energy had little effect on the transformations and toxicity of AgNPs. While in the presence of histidine with higher Ag(+) binding energy, the Ag(+) release and particle size of AgNPs obviously increased. These transformations resulted in a decrease in the cytotoxicity of AgNPs due to the formation of Ag-His complex and the growth of AgNPs. Furthermore, l-cysteine with the highest Ag(+) binding energy could easily interact with AgNPs, transforming them completely to form [Ag(Cys)n](+) and Ag2S precipitates, which induced the largest decrease in AgNP toxicity. In summary, our results may provide useful information to understand the fate, transformation, and toxicity of citrate-coated AgNPs in the human body. PMID:24910988

Shi, Junpeng; Sun, Xia; Zou, Xiaoyan; Zhang, Hongwu

2014-08-17

136

Microbial transformation of acetyl-11-keto-?-boswellic acid and their inhibitory activity on LPS-induced NO production.  

PubMed

The capabilities of 20 strains of fungi to transform acetyl-11-keto-?-boswellic (AKBA) were screened. And biotransformation of AKBA by Cunninghamella blakesleana AS 3.970 afforded five metabolites (1-5), while two metabolites (6, 7) were isolated from biotransformation of Cunninghamella elegans AS 3.1207. The chemical structures of these metabolites were identified by spectral methods including 2D NMR and their structures were elucidated as 7?-hydroxy-3-acety-11-keto-?-boswellic acid (1), 21?-dihydroxy-3-acety-11-keto-?-boswellic acid (2), 7?,22?-dihydroxy-3-acety-11-keto-?-boswellic acid (3), 7?,16?-dihydroxy-3-acety-11-keto-?-boswellic acid (4), 7?,15?-dihydroxy-3-acety-11-keto-?-boswellic acid (5); 7?,15?,21?-trihydroxy-3-acety-11-keto-?-boswellic acid (6) and 15?,21?-dihydroxy-3-acety-11-keto-?-boswellic acid (7). All these products are previously unknown. Their primary structure-activity relationships (SAR) of inhibition activity on LPS-induced NO production in RAW 264.7 macrophage cells were evaluated. PMID:23391590

Sun, Yan; Liu, Dan; Xi, Ronggang; Wang, Xiaobo; Wang, Yan; Hou, Jie; Zhang, Baojing; Wang, Changyuan; Liu, Kexin; Ma, Xiaochi

2013-03-01

137

Transformations of Glycyrrhizic Acid: XV. Synthesis of Triterpene Saponins with Monosaccharide Residues Attached through Ester Bonds  

Microsoft Academic Search

Triterpene saponins, glycoside analogues of glycyrrhizic acid with a modified carbohydrate chain containing monosaccharide residues attached through ester bonds, were synthesized. To this end, peracetylated glycyrrhizic acid or its 30-methyl ester were glycosylated by 2,3,4,6-tetra-O-acetyl-a-D-gluco- or -a-D-galactopyranosyl bromide in dichloroethane in the presence of Ag2CO3. Glycerrhetinic acid saponin with D-Galp residues exhibited a higher antiulcer activity than glycyrrhizic acid in

R. M. Kondratenko; L. A. Baltina; S. R. Mustafina; E. V. Vasil'eva; A. F. Ismagilova; N. G. Vasil'eva; G. A. Tolstikov

2003-01-01

138

Metabolism of fatty acids and lipid hydroperoxides in human body monitoring with Fourier transform Infrared Spectroscopy  

Microsoft Academic Search

BACKGROUND: The metabolism of dietary fatty acids in human has been measured so far using human blood cells and stable-isotope labeled fatty acids, however, no direct data was available for human peripheral tissues and other major organs. To realize the role of dietary fatty acids in human health and diseases, it would be eager to develop convenient and suitable method

Satoshi Yoshida; Qin-Zeng Zhang; Shu Sakuyama; Satoshi Matsushima

2009-01-01

139

Catalytic transformation of alcohols to carboxylic acid salts and H2 using water as the oxygen atom source  

NASA Astrophysics Data System (ADS)

The oxidation of alcohols to carboxylic acids is an important industrial reaction used in the synthesis of bulk and fine chemicals. Most current processes are performed by making use of either stoichiometric amounts of toxic oxidizing agents or the use of pressurized dioxygen. Here, we describe an alternative dehydrogenative pathway effected by water and base with the concomitant generation of hydrogen gas. A homogeneous ruthenium complex catalyses the transformation of primary alcohols to carboxylic acid salts at low catalyst loadings (0.2 mol%) in basic aqueous solution. A consequence of this finding could be a safer and cleaner process for the synthesis of carboxylic acids and their derivatives at both laboratory and industrial scales.

Balaraman, Ekambaram; Khaskin, Eugene; Leitus, Gregory; Milstein, David

2013-02-01

140

Synthesis, structure and characterization of a new tellurate: NaBiTeO 5  

NASA Astrophysics Data System (ADS)

A new tellurate, NaBiTeO 5 has been synthesized by standard solid-state techniques using Na 2CO 3, Bi 2O 3, and TeO 2 as reagents. The structure of NaBiTeO 5 was determined by single crystal X-ray diffraction. NaBiTeO 5 crystallizes in the monoclinic space group P2 1/c (No. 14), with a=7.2645(5), b=9.8048(6), c=6.2718(4) Å, ?=106.819(1)°, V=427.61(5) Å 3 and Z=4. NaBiTeO 5 has a novel three-dimensional framework consisting of chains of [TeO 6/2] 0 octahedra that are linked by [BiO 4/2] - polyhedra. Bi 3+ is in an asymmetric coordination environment attributable to its lone-pair. The lone-pair on the Bi 3+ point in the [1 0 0] and [0 0 -1] directions and interacts with the Na + cation. Infrared and thermogravimetric analyzes are also presented.

Ok, Kang Min; Halasyamani, P. Shiv

2002-05-01

141

Vaporization behaviour and thermodynamic stability of zirconium tellurate ZrTe 3O 8  

NASA Astrophysics Data System (ADS)

The standard Gibbs energy of formation for zirconium tellurate ZrTe 3O 8 was derived from its vapour pressure measured in the temperature range 1008 to 1146 K, employing the transpiration technique. ZrTe 3O 8 vaporizes incongruently, according to the reaction ai + 3(TeO 2). The standard Gibbs energy of formation ( ?fG°) of calculated from the partial pressure of TeO 2(g) in the vapour phase above the < ZrO2> + < ZrTe3O8> mixture can be represented by the relation ?fG°(± 14.3 kJ mol -1) = -2168.3 + 0.801 T( K) (1008 ? T/ K ? 1146). The standard enthalpy of formation ?fH°(298.15 K) for derived from these data employing the estimated heat capacity for the compound was found to be -(2153.0 ± 18.3) kJmol-1, in good agreement with the value of -(2131.2 ± 9.64) kJmol-1 determined by isoperibol calorimetry.

Samant, M. S.; Bharadwaj, S. R.; Kerkar, A. S.; Tripathi, S. N.; Dharwadkar, S. R.

1994-08-01

142

Structural transformation induced by locked nucleic acid or 2?-O-methyl nucleic acid site-specific modifications on thrombin binding aptamer  

PubMed Central

Background Locked nucleic acid (LNA) and 2'–O-methyl nucleic acid (OMeNA) are two of the most extensively studied nucleotide derivatives in the last decades. However, how they affect DNA quadruplex structures remains largely unknown. To explore their possible biological affinities for quadruplexes, we investigated how LNA- or OMeNA-substitutions affect G-quadruplex structure formation using a thrombin binding aptamer (TBA), the most studied extracorporal G-quadruplex-forming DNA sequence, which is frequently modified to increase its analytical performance. Results The experimental results showed that when two or more nucleotides were substituted with LNA or OMeNA, the anti-parallel TBA structure was transformed into an unstructured random conformation in a 50 mM K+ environment; OMeNA appeared to have greater power to induce this transformation. However, the native TBA was unstructured in a 50 mM Ca2+ environment, whereas four or more LNA- or OMeNA- substitutions could convert this unstructured TBA into a parallel quadruplex structure. PAGE mobility measurements suggested that these TBAs might be a dimeric form. Conclusion LNA or 2'-OMeNA site-specific modifications induced G-quadruplex structural transformation of TBA, which enriched our understanding of the intrinsic G-quadrupex forming property and affinity of LNA and OMeNA modifications. This study demonstrates possible applications in the regulation of gene expression (i.e. manual intervention of gene therapy), genetic analyses, molecular diagnosis and the construction of nano-scale biostructures.

2014-01-01

143

Polyfunctional compounds containing the 4,6-dialkoxy-7-arylthioheptene moiety as synthetically useful intermediates. The course of lewis acid-induced transformations.  

PubMed

Data on the selectivity of the Lewis acids induced transformations of the title compounds are presented, and the routes leading to formation of products containing either cyclohexane or 1,3-diene units are described. PMID:12423123

Chekmarev, Dmitriy S; Lazareva, Margarita I; Zatonsky, Georgy V; Maskaev, Andrei V; Caple, Ron; Smit, William

2002-11-15

144

Generation of organic acids and monosaccharides by hydrolytic and oxidative transformation of food processing residues.  

PubMed

Carbohydrate-rich biomass residues, i.e. sugar beet molasses, whey powder, wine yeast, potato peel sludge, spent hops, malt dust and apple marc, were tested as starting materials for the generation of marketable chemicals, e.g. aliphatic acids, sugar acids and mono-/disaccharides. Residues were oxidized or hydrolyzed under acidic or alkaline conditions applying conventional laboratory digestion methods and microwave assisted techniques. Yields and compositions of the oxidation products differed according to the oxidizing agent used. Main products of oxidation by 30% HNO(3) were acetic, glucaric, oxalic and glycolic acids. Applying H(2)O(2)/CuO in alkaline solution, the organic acid yields were remarkably lower with formic, acetic and threonic acids as main products. Gluconic acid was formed instead of glucaric acid throughout. Reaction of a 10% H(2)O(2) solution with sugar beet molasses generated formic and lactic acids mainly. Na(2)S(2)O(8) solutions were very inefficient at oxidizing the residues. Glucose, arabinose and galactose were formed during acidic hydrolysis of malt dust and apple marc. The glucose content reached 0.35 g per gram of residue. Important advantages of the microwave application were lower reaction times and reduced reagent demands. PMID:15607197

Fischer, Klaus; Bipp, Hans-Peter

2005-05-01

145

Fractionation of native and denatured transforming deoxyribonucleic acid from Bacillus subtilis  

PubMed Central

1. Native DNA from Bacillus subtilis was fractionated by stepwise elution from methylated albumin, the transforming activity being confined to two out of four fractions. Partial separation of DNA active in transformation for the arginine marker from that showing activity for the histidine and tryptophan markers was achieved. 2. Partial denaturation of DNA at 90° and 93·5° resulted in the preferential destruction of transforming activity for the histidine and tryptophan markers. 3. Denaturation of DNA at 100° followed by chromatography on methylated albumin yielded five fractions, two of which exhibited residual activity. Redenaturation at 100° resulted in the interconversion of four out of the five fractions. Redenaturation of fractions labelled with 15N and 2H suggested the presence of a specific component that did not readily take part in the interconversions.

Ayad, S. R.; Barker, G. R.; Weigold, Josephine

1968-01-01

146

Fractionation of native and denatured transforming deoxyribonucleic acid from Bacillus subtilis.  

PubMed

1. Native DNA from Bacillus subtilis was fractionated by stepwise elution from methylated albumin, the transforming activity being confined to two out of four fractions. Partial separation of DNA active in transformation for the arginine marker from that showing activity for the histidine and tryptophan markers was achieved. 2. Partial denaturation of DNA at 90 degrees and 93.5 degrees resulted in the preferential destruction of transforming activity for the histidine and tryptophan markers. 3. Denaturation of DNA at 100 degrees followed by chromatography on methylated albumin yielded five fractions, two of which exhibited residual activity. Redenaturation at 100 degrees resulted in the interconversion of four out of the five fractions. Redenaturation of fractions labelled with (15)N and (2)H suggested the presence of a specific component that did not readily take part in the interconversions. PMID:4297046

Ayad, S R; Barker, G R; Weigold, J

1968-04-01

147

Near-infrared quantum cutting in Pr3+/Yb3+ co-doped transparent tellurate glass via two step energy transfer  

NASA Astrophysics Data System (ADS)

A series of Pr3+/Yb3+ co-doped transparent tellurate glass samples were prepared by high-temperature melting method. The optical properties and energy transfer process from Pr3+ to Yb3+ were investigated. On excitation of Pr3+ ions with a blue visible photon at 449 nm, a near infrared emission at 1001 nm were observed in the Pr3+/Yb3+ co-doped tellurate glass, which is attributed to 2F?2F transition of Yb3+ ions. The feeding of Yb3+ ions is shown to be two step energy transfer from Pr3+ through 1G multiplet by excitation and emission spectra. The maximum total quantum efficiency reaches 136.7% when the co-doped Yb3+ mole concentration is 5%. The efficient down-conversion near infrared emission of Pr3+/Yb3+ co-doped tellurate glass has potential application in enhancing the conversion efficiency of crystalline silicon based solar cells.

Zhou, Xianju; Wang, Guangchuan; Zhou, Kaining; Li, Qingxu

2013-01-01

148

A broadband Fourier-transform microwave spectrometer with laser ablation source: The rotational spectrum of nicotinic acid  

NASA Astrophysics Data System (ADS)

A chirped pulse Fourier transform microwave spectrometer (CP-FTMW) has been combined with a laser ablation source to investigate the broadband rotational spectra of solid biomolecules in the 6.0-18 GHz region. This technique has been successfully applied to the conformational study of nicotinic acid for which two conformers have been characterized for the first time in the gas phase. The quadrupole hyperfine structure originated by a 14N nucleus has been completely resolved for both rotamers using a LA-MB-FTMW spectrometer.

Mata, S.; Peña, I.; Cabezas, C.; López, J. C.; Alonso, J. L.

2012-10-01

149

Linking photochemical transformation of an Antarctica Fulvic Acid to diminished bioavailability and oxidation of organic electron shuttles  

NASA Astrophysics Data System (ADS)

Photolysis of fulvic acid isolated from Pony Lake, Antarctica, a hypereutrophic coastal pond located on Ross Island, was evaluated for transformation kinetics and photo-bleaching mechanisms by spectroscopy, as well as changes in bioavailability. The fulvic acid fraction of Pony Lake was isolated by sorption to non-ionic XAD-8 resin, and represents the fraction of the dissolved organic matter considered to be the most photo-reactive fraction. Spectroscopic and electrochemical analysis during Pony Lake fulvic acid photolysis reveals three fundamental alterations to the natural organic matter isolate: decreased molar absorptivity, decreased fluorescence, and a loss of reduced organic functional groups (potential electron shuttles). Surprisingly we observed no carbon loss to mineralization. Evaluation of the light absorbance decay kinetics in the presence/absence of oxygen indicate that approximately 70% of photo-bleaching occurs via direct pathways and 30% is due to reaction with photochemically generated reactive oxygen species (ROS). Of the ROS mediated pathways approximately 70% of the reactivity is attributable to hydroxyl-radical oxidation. Molecular level changes in fulvic acid showed a loss of electron-rich (reduced) components during photolysis, specifically redox active N/S functional groups. Reduced forms of organic nitrogen (amines) decrease in concentration, while sulfur moieties (thiols) are essentially eliminated during photolysis. Furthermore, as the suite of reduced fulvic acid components are photochemically oxidized, we observe a concomitant production of hydrogen peroxide, presumably due to the photo-reduction of dissolved oxygen coupled to organic matter oxidation. Decay kinetics of fluorescent components identified in the fulvic acid isolate were evaluated using parallel factor component analysis (PARAFAC) of excitation-emission matrices (EEMs), and further illustrate a loss of overall fluorescence and a decrease in the redox-active (electron- shuttling) components of the fulvic acid. These molecular-scale changes in photo-chemically altered fulvic acid illustrate a general trend towards broad-scale oxidation of chromophores, fluorophores, and reduced organic N/S functionalities. The loss of electron-donating capacity was correlated to decreases in relative concentrations of redox-active moieties in microbially-derived fulvic acid and suggests that photolysis attacks the electron shuttling properties of the fulvic acid. Photochemical oxidation of electron-rich functional groups and chemical degradation of organic electron shuttles may be related to the decreased bioavailability of photolyzed fulvic acid.

Fimmen, R. L.; Guerard, J. J.; Miller, P. L.; Cory, R. M.; Chin, Y.; Foreman, C. M.; McKnight, D. M.

2007-12-01

150

Fourier transform infrared studies of model polar stratospheric cloud surfaces - Growth and evaporation of ice and nitric acid/ice  

NASA Technical Reports Server (NTRS)

Fourier-transform infrared surface studies are used to probe the microphysical properties of nitric acid trihydrate (NAT) and ice films representative of type I and II polar stratospheric clouds (PSC). Experiments indicate that, on initial exposure to 1.8 microtorr of HNO3, a layer of ice is quantitatively converted to NAT. However, conversion of ice to NAT does not proceed indefinitely, but rather the system reaches saturation. For longer exposures or higher HNO3 pressures, NAM becomes the dominant nitric acid containing species on the surface. Evaporation studies were performed to test the feasibility of a recent denitrification mechanism. The results indicate that ice coated with 0.20 micron of NAT evaporates at a temperature of about 4 C higher than uncoated ice.

Tolbert, Margaret A.; Middlebrook, Ann M.

1990-01-01

151

Synthesis, calorimetric, structural and conductivity studies in a new thallium selenate tellurate adduct compound  

SciTech Connect

The crystal structure of the thallium selenate tellurate Tl{sub 2}SeO{sub 4}.Te(OH){sub 6} (TlSeTe) was determined by X-ray diffraction method. The title compound crystallizes in the monoclinic system with P2{sub 1}/c space group. The following parameters are: a = 12.358(3) A; b = 7.231(1) A; c = 11.986(2) A; {beta} = 111.092(2){sup o}; Z = 4. The structure can be regarded as being built of isolated TeO{sub 6} octahedra and SeO{sub 4} tetrahedra. The Tl{sup +} cations are intercalated between these kinds of polyhedra. The main feature of this structure is the coexistence of two different and independent anions (SeO{sub 4}{sup 2-} and TeO{sub 6}{sup 6-}) in the same unit cell. The structure is stable due to O-H...O hydrogen bonds which link tetrahedral and octahedral groups. Crystals of Tl{sub 2}SeO{sub 4}.Te(OH){sub 6} undergo three endothermal transitions at 373, 395 and 437 K. These transitions are detected by DSC and analyzed by dielectric measurements with impedance spectroscopy. The evolution of conductivity versus temperature showed the presence of a protonic conduction phase transition at 437 K. The phase transition at 373 K can be related to a structural phase transition, whereas the one at 395 K is ascribed as likely due to a ferroelectric-paraelectric phase transition.

Ktari, L. [Laboratoire de l'Etat Solide (LES), Faculte des Sciences de Sfax, 3000 Sfax (Tunisia); Abdelhedi, M. [Laboratoire de l'Etat Solide (LES), Faculte des Sciences de Sfax, 3000 Sfax (Tunisia); Laboratoire Leon Brouillon LLB, CEA Saclay, 91191 Gif-Sur-Yvette Cedex (France); Bouhlel, N. [Laboratoire de l'Etat Solide (LES), Faculte des Sciences de Sfax, 3000 Sfax (Tunisia); Dammak, M., E-mail: meddammak@yahoo.fr [Laboratoire de l'Etat Solide (LES), Faculte des Sciences de Sfax, 3000 Sfax (Tunisia); Cousson, A. [Laboratoire Leon Brouillon LLB, CEA Saclay, 91191 Gif-Sur-Yvette Cedex (France)

2009-08-05

152

The local structure of gadolinium vanadate–tellurate glasses and glass ceramics: Te 2 V 2 O 9 crystalline phase  

Microsoft Academic Search

Glasses in the system xGd2O3 · (100 ? x)[0.7TeO2 · 0.3V2O5] with 0 ? x ?20 mol% have been prepared from melt quenching method. Influence of gadolinium ions on structural behavior in vanadate–tellurate\\u000a glasses has been investigated using FTIR spectroscopy, X-ray diffraction (XRD), and magnetic susceptibility measurements.\\u000a The structural changes have been analyzed with increasing rare earth concentration. The structural changes, as recognized\\u000a by analyzing band shapes of XRD and

Simona Rada; Maria Bosca; Eugen Culea; Marius Rada; Viorel Dan; Vistrian Maties

2009-01-01

153

Prediction of humic acid content and respiration activity of biogenic waste by means of Fourier transform infrared (FTIR) spectra and partial least squares regression (PLS-R) models  

Microsoft Academic Search

Fourier transform infrared (FTIR) spectroscopy has been proven to be an appropriate analytical method for the qualitative assessment of compost stability. This study focuses on quantitative determination of two time-consuming parameters: humic acid (HA) contents and respiration activity. Reactivity\\/stability and humification were quantified by respiration activities (oxygen uptake) and humic acid contents. These features are also reflected by a specific

Katharina Meissl; Ena Smidt; Manfred Schwanninger

2007-01-01

154

Adsorption of Amino Acids (Ala, Cys, His, Met) on Zeolites: Fourier Transform Infrared and Raman Spectroscopy Investigations  

NASA Astrophysics Data System (ADS)

Minerals adsorb more amino acids with charged R-groups than amino acids with uncharged R-groups. Thus, the peptides that form from the condensation of amino acids on the surface of minerals should be composed of amino acid residues that are more charged than uncharged. However, most of the amino acids (74%) in today's proteins have an uncharged R-group. One mechanism with which to solve this paradox is the use of organophilic minerals such as zeolites. Over the range of pH (pH 2.66-4.50) used in these experiments, the R-group of histidine (His) is positively charged and neutral for alanine (Ala), cysteine (Cys), and methionine (Met). In acidic hydrothermal environments, the pH could be even lower than those used in this study. For the pH range studied, the zeolites were negatively charged, and the overall charge of all amino acids was positive. The conditions used here approximate those of prebiotic Earth. The most important finding of this work is that the relative concentrations of each amino acid (X=His, Met, Cys) to alanine (X/Ala) are close to 1.00. This is an important result with regard to prebiotic chemistry because it could be a solution for the paradox stated above. Pore size did not affect the adsorption of Cys and Met on zeolites, and the Si/Al ratio did not affect the adsorption of Cys, His, and Met. ZSM-5 could be used for the purification of Cys from other amino acids (Student-Newman-Keuls test, p<0.05), and mordenite could be used for separation of amino acids from each other (Student-Newman-Keuls test, p<0.05). As shown by Fourier transform infrared (FT-IR) spectra, Ala interacts with zeolites through the group, and methionine-zeolite interactions involve the COO, , and CH3 groups. FT-IR spectra show that the interaction between the zeolites and His is weak. Cys showed higher adsorption on all zeolites; however, the hydrophobic Van der Waals interaction between zeolites and Cys is too weak to produce any structural changes in the Cys groups (amine, carboxylic, sulfhydryl, etc.); thus, the FT-IR and Raman spectra are the same as those of solid Cys.

Carneiro, Cristine E. A.; de Santana, Henrique; Casado, Clara; Coronas, Joaquin; Zaia, Dimas A. M.

2011-06-01

155

Adsorption of amino acids (ALA, CYS, HIS, MET) on zeolites: fourier transform infrared and Raman spectroscopy investigations.  

PubMed

Minerals adsorb more amino acids with charged R-groups than amino acids with uncharged R-groups. Thus, the peptides that form from the condensation of amino acids on the surface of minerals should be composed of amino acid residues that are more charged than uncharged. However, most of the amino acids (74%) in today's proteins have an uncharged R-group. One mechanism with which to solve this paradox is the use of organophilic minerals such as zeolites. Over the range of pH (pH 2.66-4.50) used in these experiments, the R-group of histidine (His) is positively charged and neutral for alanine (Ala), cysteine (Cys), and methionine (Met). In acidic hydrothermal environments, the pH could be even lower than those used in this study. For the pH range studied, the zeolites were negatively charged, and the overall charge of all amino acids was positive. The conditions used here approximate those of prebiotic Earth. The most important finding of this work is that the relative concentrations of each amino acid (X=His, Met, Cys) to alanine (X/Ala) are close to 1.00. This is an important result with regard to prebiotic chemistry because it could be a solution for the paradox stated above. Pore size did not affect the adsorption of Cys and Met on zeolites, and the Si/Al ratio did not affect the adsorption of Cys, His, and Met. ZSM-5 could be used for the purification of Cys from other amino acids (Student-Newman-Keuls test, p<0.05), and mordenite could be used for separation of amino acids from each other (Student-Newman-Keuls test, p<0.05). As shown by Fourier transform infrared (FT-IR) spectra, Ala interacts with zeolites through the [Formula: see text] group, and methionine-zeolite interactions involve the COO, [Formula: see text], and CH(3) groups. FT-IR spectra show that the interaction between the zeolites and His is weak. Cys showed higher adsorption on all zeolites; however, the hydrophobic Van der Waals interaction between zeolites and Cys is too weak to produce any structural changes in the Cys groups (amine, carboxylic, sulfhydryl, etc.); thus, the FT-IR and Raman spectra are the same as those of solid Cys. PMID:21671763

Carneiro, Cristine E A; de Santana, Henrique; Casado, Clara; Coronas, Joaquin; Zaia, Dimas A M

2011-06-01

156

Microbial transformations of ferulic acid by Saccharomyces cerevisiae and Pseudomonas fluorescens.  

PubMed Central

Saccharomyces cerevisiae (dry baker's yeast) and Pseudomonas fluorescens were used to convert trans-ferulic acid into 4-hydroxy-3-methoxystyrene in 96 and 89% yields, respectively. The metabolites were isolated by solid-phase extraction and analyzed by thin-layer chromatography and high-performance liquid chromatography. The identities of the metabolites were determined by 1H- and 13C-nuclear magnetic resonance spectroscopy and by mass spectrometry. The mechanism of the decarboxylation of ferulic acid was investigated by measuring the degree and position of deuterium incorporated into the styrene derivative from D2O by mass spectrometry and by both proton and deuterium nuclear magnetic resonance spectroscopies. Resting cells of baker's yeast reduced ferulic acid to 4-hydroxy-3-methoxyphenylpropionic acid in 54% yield when incubations were under an argon atmosphere.

Huang, Z; Dostal, L; Rosazza, J P

1993-01-01

157

Microbial transformations of ferulic acid by Saccharomyces cerevisiae and Pseudomonas fluorescens.  

PubMed

Saccharomyces cerevisiae (dry baker's yeast) and Pseudomonas fluorescens were used to convert trans-ferulic acid into 4-hydroxy-3-methoxystyrene in 96 and 89% yields, respectively. The metabolites were isolated by solid-phase extraction and analyzed by thin-layer chromatography and high-performance liquid chromatography. The identities of the metabolites were determined by 1H- and 13C-nuclear magnetic resonance spectroscopy and by mass spectrometry. The mechanism of the decarboxylation of ferulic acid was investigated by measuring the degree and position of deuterium incorporated into the styrene derivative from D2O by mass spectrometry and by both proton and deuterium nuclear magnetic resonance spectroscopies. Resting cells of baker's yeast reduced ferulic acid to 4-hydroxy-3-methoxyphenylpropionic acid in 54% yield when incubations were under an argon atmosphere. PMID:8395165

Huang, Z; Dostal, L; Rosazza, J P

1993-07-01

158

Bacterial production and transformation of dissolved neutral sugars and amino acids in seawater  

NASA Astrophysics Data System (ADS)

Dissolved organic matter (DOM) in the ocean consists of a heterogeneous mixture of molecules, most of which are of unknown origin. Neutral sugars and amino acids are among the few recognizable biomolecules in DOM, and the molecular composition of these biomolecules is shaped primarily by biological production and degradation processes. This study provides insight into the bioavailability of biomolecules as well as the chemical composition of DOM produced by bacteria. The molecular compositions of neutral sugars and amino acids were investigated in DOM produced by bacteria and in DOM remaining after long-term bacterial degradation. Results from bioassay incubations (32 days) with natural and artificial seawater, indicate that the molecular compositions following bacterial degradation are not strongly influenced by the initial substrate or bacterial community. The molecular composition of neutral sugars released by bacteria was characterized by a high glucose content (47 mol%) and heterogeneous contributions from other neutral sugars (3-14 mol%). DOM remaining after bacterial degradation was characterized by a high galactose content (33 mol%), followed by glucose (22 mol%) and the remaining neutral sugars (7-11 mol%). The ratio of D-amino acids to L-amino acids increased during the experiments as a response to bacterial degradation, and after 32 days the D/L ratios of aspartic acid, glutamic acid, serine and alanine reached around 0.79, 0.32, 0.30 and 0.51 in all treatments, respectively. The striking similarity in neutral sugar and amino acid compositions between natural and artificial seawater samples, suggests that the microbial carbon pump also applies for neutral sugars and amino acids and that bacterially-produced biomolecules persist for long periods in the ocean.

Jørgensen, L.; Lechtenfeld, O.; Benner, R.; Middelboe, M.; Stedmon, C. A.

2014-04-01

159

High-resolution Fourier transform ion cyclotron resonance mass spectrometry of humic and fulvic acids: improvements and comparisons.  

PubMed

Full structural characterization of complex mixtures such as humic acid extracts has been elusive because of insufficient compound resolution with conventional techniques. Using electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry, we were able to resolve individual compounds within humic and fulvic acid mixtures (mass resolving power approximately 80000 at 300 m/z). We examined two samples in detail: (1) dissolved organic matter (primarily fulvic acids) from Suwannee River, GA, and (2) a humic acid extract from a degraded wood collected on Mt. Rainier, WA. Sample conditions (such as solvent, pH, and concentration) and instrument parameters (such as source voltages, trapping potentials, and excitation parameters) were optimized to yield the highest mass resolving power with the least mass discrimination in positive ion mode. High resolving power was achieved with low ion densities combined with coadding numerous scans. The increased resolution allowed molecular-level comparisons of the two samples which in turn could be used to estimate the relative similarity of individual compound distribution as well as an indication of the dominant diagenetic processes in the two source environments. PMID:11811416

Kujawinski, Elizabeth B; Hatcher, Patrick G; Freitas, Michael A

2002-01-15

160

Hypoxic and Ras-transformed cells support growth by scavenging unsaturated fatty acids from lysophospholipids  

PubMed Central

Cancer cell growth requires fatty acids to replicate cellular membranes. The kinase Akt is known to up-regulate fatty acid synthesis and desaturation, which is carried out by the oxygen-consuming enzyme stearoyl-CoA desaturase (SCD)1. We used 13C tracers and lipidomics to probe fatty acid metabolism, including desaturation, as a function of oncogene expression and oxygen availability. During hypoxia, flux from glucose to acetyl-CoA decreases, and the fractional contribution of glutamine to fatty acid synthesis increases. In addition, we find that hypoxic cells bypass de novo lipogenesis, and thus, both the need for acetyl-CoA and the oxygen-dependent SCD1-reaction, by scavenging serum fatty acids. The preferred substrates for scavenging are phospholipids with one fatty acid tail (lysophospholipids). Hypoxic reprogramming of de novo lipogenesis can be reproduced in normoxic cells by Ras activation. This renders Ras-driven cells, both in culture and in allografts, resistant to SCD1 inhibition. Thus, a mechanism by which oncogenic Ras confers metabolic robustness is through lipid scavenging.

Kamphorst, Jurre J.; Cross, Justin R.; Fan, Jing; de Stanchina, Elisa; Mathew, Robin; White, Eileen P.; Thompson, Craig B.; Rabinowitz, Joshua D.

2013-01-01

161

A study of the autoxidation of some unsaturated fatty acid methyl esters using Fourier transform Raman spectroscopy  

NASA Astrophysics Data System (ADS)

Near-infrared Fourier transform Raman and Fourier transform infrared spectroscopy have been used to investigate the chemical changes taking place during the curing reaction of several fatty acid methyl esters, which are used for modelling processes in the autoxidation of alkyd resin coatings. We have studied methyl oleate, methyl linoleate, and methyl linolenate in an attempt to monitor the degree of unsaturation within the fatty acid methyl esters (FAMES) during the complex autoxidation/polymerisation reaction that takes place once the paint system is coated onto a substrate and exposed to the atmosphere. The peaks around 1655 cm -1 have been assigned as follows: to the trans isomer at 1670 cm -1, the cis isomer at 1655 cm -1 and the conjugated structure at 1640 cm -1 [B. Schrader, Raman/Infrared Atlas of Organic Compounds (2nd Edn), VCH, Weinheim (1989); J. K. Abenyega, M. Claybourn and G. Ellis, in preparations]. Raman spectra for the cure of methyl linoleate after 24 h show several interesting features, suggesting the formation of a highly conjugated cyclic structure. Current theories about the mechanism for the autoxidation of methyl linoleate make no mention of this aromatic product.

Agbenyega, J. K.; Claybourn, M.; Ellis, G.

162

Chromatography of transforming deoxyribonucleic acid on methylated albumin and by gel filtration  

PubMed Central

1. Native DNA from two strains of Bacillus subtilis was chromatographed by stepwise elution from MAK (methylated albumin on kieselguhr). 2. Transforming activity was confined to two out of the three main fractions, activity being distributed between the two peaks differently for DNA from the different strains. 3. Fractionation of DNA from both strains on 2% agarose gel gave two components. Approx. 75% of the material was eluted within the void volume of the column. Approx. 25% of the material consisted of degradation products of lower molecular weight. 4. Chromatography on MAK of the material of high molecular weight eluted from agarose gel gave a number of peaks differing in molecular weight, indicating that degradation of the DNA takes place during chromatography on MAK. 5. The distribution of transforming activity among the fractions from MAK suggests that degradation occurs preferentially in certain regions of the DNA.

Barker, G. R.; Hodges, P.

1974-01-01

163

Suberoylanilide hydroxamic acid (SAHA) inhibits EGF-induced cell transformation via reduction of cyclin D1 mRNA stability  

SciTech Connect

Suberoylanilide hydroxamic acid (SAHA) inhibiting cancer cell growth has been associated with its downregulation of cyclin D1 protein expression at transcription level or translation level. Here, we have demonstrated that SAHA inhibited EGF-induced Cl41 cell transformation via the decrease of cyclin D1 mRNA stability and induction of G0/G1 growth arrest. We found that SAHA treatment resulted in the dramatic inhibition of EGF-induced cell transformation, cyclin D1 protein expression and induction of G0/G1 growth arrest. Further studies showed that SAHA downregulation of cyclin D1 was only observed with endogenous cyclin D1, but not with reconstitutionally expressed cyclin D1 in the same cells, excluding the possibility of SAHA regulating cyclin D1 at level of protein degradation. Moreover, SAHA inhibited EGF-induced cyclin d1 mRNA level, whereas it did not show any inhibitory effect on cyclin D1 promoter-driven luciferase reporter activity under the same experimental conditions, suggesting that SAHA may decrease cyclin D1 mRNA stability. This notion was supported by the results that treatment of cells with SAHA decreased the half-life of cyclin D1 mRNA from 6.95 h to 2.57 h. Consistent with downregulation of cyclin D1 mRNA stability, SAHA treatment also attenuated HuR expression, which has been well-characterized as a positive regulator of cyclin D1 mRNA stability. Thus, our study identifies a novel mechanism responsible for SAHA inhibiting cell transformation via decreasing cyclin D1 mRNA stability and induction of G0/G1 growth arrest in Cl41 cells. -- Highlights: ? SAHA inhibits cell transformation in Cl41 cells. ? SAHA suppresses Cyclin D1 protein expression. ? SAHA decreases cyclin D1 mRNA stability.

Zhang, Jingjie [State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, 38 Xueyuan Rd, Haidian District, Beijing 100191 (China) [State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, 38 Xueyuan Rd, Haidian District, Beijing 100191 (China); Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Rd, Tuxedo, NY 10987 (United States); Ouyang, Weiming; Li, Jingxia; Zhang, Dongyun; Yu, Yonghui; Wang, York [Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Rd, Tuxedo, NY 10987 (United States)] [Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Rd, Tuxedo, NY 10987 (United States); Li, Xuejun, E-mail: xjli@bjmu.edu.cn [State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, 38 Xueyuan Rd, Haidian District, Beijing 100191 (China)] [State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, 38 Xueyuan Rd, Haidian District, Beijing 100191 (China); Huang, Chuanshu, E-mail: chuanshu.huang@nyumc.org [Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Rd, Tuxedo, NY 10987 (United States)] [Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Rd, Tuxedo, NY 10987 (United States)

2012-09-01

164

Reactive oxygen species regulate properties of transformation in UROtsa cells exposed to monomethylarsonous acid by modulating MAPK signaling  

PubMed Central

UROtsa cells exposed to 50 nM monomethylarsonous acid [MMA(III)] for 52 wk (MSC52) achieved hyperproliferation, anchorage independent growth, and enhanced tumorgenicity. MMA(III) has been shown to induce reactive oxygen species (ROS), which can lead to activation of signaling cascades causing stress-related proliferation of cells and even cellular transformation. Previous research established the acute activation of MAPK signaling cascade by ROS produced by MMA(III) as well as chronic up regulation of COX-2 and EGFR in MSC52 cells. To determine if ROS played a role in the chronic pathway perturbations by acting as secondary messengers, activation of Ras was determined in UROtsa cells [exposed to MMA(III) for 0 –52 wk] and found to be increased through 52 wk most dramatically after 20 wk of exposure. Ras has been shown to cause an increase in O2·? and be activated by increases in O2·?, making ROS important to study in the transformation process. COX-2 upregulation in MSC52 cells was confirmed by real time RT-PCR. By utilizing both antioxidants or specific COX inhibitors, it was shown that COX-2 upregulation was dependent on ROS, specifically, O2·?. In addition, because previous research established the importance of MAPK activation in phenotypic changes associated with transformation in MSC52 cells, it was hypothesized that ROS play a role in maintaining phenotypic characteristics of the malignant transformation of MSC52 cells. Several studies have demonstrated that cancer cells have lowered superoxide dismutase (MnSOD) activity and protein levels. Increasing levels of MnSOD have been shown to suppress the malignant phenotype of cells. SOD was added to MSC52 cells resulting in slower proliferation rates (doubling time = 42 h vs 31 h). ROS scavengers of ·OH also slowed proliferation rates of MSC52 cells. To further substantiate the importance of ROS in these properties of transformation in MSC52 cells, anchorage independent growth was assessed after the addition of antioxidants, both enzymatic and non-enzymatic. Scavengers of·OH, and O2·? blocked the colony formation of MSC52 cells. These data support the role for the involvement of ROS in properties of transformation of UROtsa cells exposed to MMA(III).

Eblin, K.E.; Jensen, T.J.; Wnek, S.M.; Buffington, S.E.; Futscher, B.W.; Gandolfi, A.J.

2009-01-01

165

Transformation of benign Barrett's epithelium by repeated acid and bile exposure over 65 weeks: a novel in vitro model.  

PubMed

The mechanism by which gastroesophageal reflux promotes metaplasia?dysplasia?carcinoma is unknown. The aim of the study is to determine if repeated exposure to acid and bile confers a tumorigenic phenotype in a telomerase (hTERT)-immortalized benign Barrett's cell line (BAR-T). BAR-T cells were exposed to acid (pH 4) (A) and bile salt (200 ?M glycochenodeoxycholic acid) (B) daily for 5 min up to 65+ weeks. The control cells were grown in parallel without any A or B treatment. Cell morphology, proliferation, transformation, and molecular changes in the gene expression for COX-2, TC22, p53 and p53 target genes were analyzed at 8-12 weeks intervals. At 46 weeks BAR-T cells exposed to (A+B) showed distinct phenotypic changes: forming clusters and acini, and at 65 weeks displayed foci in monolayer, and formed distinct colonies in soft agar. Untreated cells did not show any such changes. In A+B-treated BAR-T cells, COX-2 mRNA increased 10- to 20-fold, TC22 mRNA increased by 2- to 3-fold at 22-65 weeks, p53, MDM2, PERP, and p21mRNA increased 2.5-, 6.4-, 4-, and 2.6-fold respectively when compared to untreated cells at 34 weeks. However, at 58 weeks onward, there was a sharp decline of p53 and its target genes to the baseline level. At 65 weeks A+B-treated BAR-T cells formed tumor in nude mice whereas untreated cells did not. We demonstrate a novel in vitro model of transformation of a benign Barrett's cell line following repeated exposure to A+B over the course of 65 weeks. PMID:20309934

Das, Kiron M; Kong, Yingxin; Bajpai, Manisha; Kulkarni, Diptee; Geng, Xin; Mishra, Pravin; Banerjee, Debabrata; Hirshfield, Kim

2011-01-15

166

Transformation of fatty acid hydroperoxides by alkali and characterization of products  

Microsoft Academic Search

It has previously been determined that (13S,9Z,11E)-13-hydroperoxy-9,11-octadecadienoic acid was mainly converted into (13S,9Z,11E)-13-hydroxy-9,11-octadecadienoic acid by 5 N KHO with preservation of the stereochemistry of the reactant [Simpson, T.D.,\\u000a and Gardner, H.W. (1993)Lipids 28, 325–330]. In addition, about 20–25% of the reactant was converted into several unknown by-products. In the present work\\u000a it was confirmed that the stereochemistry was conserved during

Harold W. Gardner; Thomas D. Simpson; Mats Hamberg

1993-01-01

167

CHEMICAL TRANSFORMATION MODULES FOR EULERIAN ACID DEPOSITION MODELS. VOLUME 2. THE AQUEOUS-PHASE CHEMISTRY  

EPA Science Inventory

This study focuses on the review and evaluation of mechanistic and kinetic data for aqueous-phase reactions that lead to the production of acidic substances in the environment. The intent of this research is to provide a framework that can be used to develop a state-of-the-art aq...

168

Analytical determination of the microbial utilization and transformation of humic acids extracted from municipal refuse  

Microsoft Academic Search

Humic substances are usually the refractory part of natural organic matter, and in a landfill they can retain inorganic and organic micropollutants. This study has investigated analytically whether humic acids (HA) extracted by use of alkali from either fresh municipal refuse or from refuse disposed of in a landfill for up to 12 months can resist microbial degradation under aerobic

Z. Filip; J. Berthelin

2001-01-01

169

CHEMICAL TRANSFORMATION MODULES FOR EULERIAN ACID DEPOSITION MODELS. VOLUME 1. THE GAS-PHASE CHEMISTRY  

EPA Science Inventory

This study focuses on the review and evaluation of mechanistic and kinetic data for the gas-phase reactions that lead to the production of acidic substances in the environment. A master mechanism is designed that treats oxides, sulfur dioxide, ozone, hydrogen peroxide, ammonia, t...

170

Comparative study of the continuous wavelet transform, derivative and partial least squares methods applied to the overlapping spectra for the simultaneous quantitative resolution of ascorbic acid and acetylsalicylic acid in effervescent tablets  

Microsoft Academic Search

The simultaneous spectrophotometric determination of ascorbic acid (AA) and acetylsalicylic acid (ASA) in effervescent tablets in the presence of the overlapping spectra was accomplished by the continuous wavelet transform (CWT), derivative spectrophotometry (DS) and partial least squares (PLS) approaches without using any chemical pre-treatment. CWT and DS calibration equations for AA and ASA were obtained by measuring the CWT and

Erdal Dinç; Abdil Ozdemir; Dumitru Baleanu

2005-01-01

171

Prediction of protein structural classes by Chou's pseudo amino acid composition: approached using continuous wavelet transform and principal component analysis.  

PubMed

A prior knowledge of protein structural classes can provide useful information about its overall structure, so it is very important for quick and accurate determination of protein structural class with computation method in protein science. One of the key for computation method is accurate protein sample representation. Here, based on the concept of Chou's pseudo-amino acid composition (AAC, Chou, Proteins: structure, function, and genetics, 43:246-255, 2001), a novel method of feature extraction that combined continuous wavelet transform (CWT) with principal component analysis (PCA) was introduced for the prediction of protein structural classes. Firstly, the digital signal was obtained by mapping each amino acid according to various physicochemical properties. Secondly, CWT was utilized to extract new feature vector based on wavelet power spectrum (WPS), which contains more abundant information of sequence order in frequency domain and time domain, and PCA was then used to reorganize the feature vector to decrease information redundancy and computational complexity. Finally, a pseudo-amino acid composition feature vector was further formed to represent primary sequence by coupling AAC vector with a set of new feature vector of WPS in an orthogonal space by PCA. As a showcase, the rigorous jackknife cross-validation test was performed on the working datasets. The results indicated that prediction quality has been improved, and the current approach of protein representation may serve as a useful complementary vehicle in classifying other attributes of proteins, such as enzyme family class, subcellular localization, membrane protein types and protein secondary structure, etc. PMID:18726140

Li, Zhan-Chao; Zhou, Xi-Bin; Dai, Zong; Zou, Xiao-Yong

2009-07-01

172

Effect of crystalline form on phase transformation kinetics of poly(l-lactic acid)  

Microsoft Academic Search

Films of poly(l-lactic acid) (PLLA) were crystallized from the amorphous solid phase at various temperatures. At crystallization temperatures lower than 120^oC, the disordered alpha' phase appears, but at crystallization temperatures greater than 120^oC, the alpha crystal forms. Crystallization kinetics was followed using far infrared (FIR) spectroscopy. Vibrations in the FIR range can be used to directly assess the interchain interactions

Jeffrey Kalish; Shaw Ling Hsu

2010-01-01

173

Transformation of isoflavone phytoestrogens during the fermentation of soymilk with lactic acid bacteria and bifidobacteria  

Microsoft Academic Search

In the present study, soymilk is fermented with lactic acid bacteria (Streptococcus thermophilus BCRC 14085, Lactobacillus acidophilus BCRC 14079) and bifidobacteria (Bifidobacterium infantis BCRC 14633, B. longum B6) individually, and in combination. The change in the content of various isoflavones (aglycones, glucoside, acetyl- and malonyl-glucosides) and the ?-glucosidase activity in soymilk during fermentation is investigated.It is observed that fermented soymilk

Hsiang-Lin Chien; Hui-Yu Huang; Cheng-Chun Chou

2006-01-01

174

Microbial transformation of tannin-rich substrate to gallic acid through co-culture method  

Microsoft Academic Search

Modified solid-state fermentation (MSSF) of tannin-rich substrate yielding tannase and gallic acid was carried out using a co-culture of the filamentous fungi, Rhizopus oryzae (RO IIT RB-13, NRRL 21498) and Aspergillus foetidus (GMRB013 MTCC 3557). Powdered fruits of Terminalia chebula and powdered pod cover of Caesalpinia digyna was used in the process and the different process parameters for maximum production

Rintu Banerjee; Gargi Mukherjee; Krushna Chandra Patra

2005-01-01

175

Structural transformation of apocytochrome c induced by alternating copolymers of maleic acid and alkene.  

PubMed

Apocytochrome c interacts with two copolymers: poly(isobutylene-alt-maleic acid) (PIMA) and poly(1-tetradecene-alt-maleic acid) (PTMA). The interaction leads to apocytochrome c, a conformational change from random coil to alpha-helical structure. The alpha-helix content is influenced by the copolymer concentration, the length of alkyl chain of the copolymers, and pH of the medium. The electrostatic attraction between the copolymer and protein is an indispensable factor for the folding of the protein at acid pH. The hydrophobic interaction is an important factor over the entire pH range, especially when both the copolymer and protein carry negative charges at alkaline pH. The electrostatic and hydrophobic attractions between the copolymer and protein exclude water molecules, promoting the formation of hydrogen bonds within the helical structure. On the other hand, the hydrogen bonds formed between the ionized carboxyl of the copolymer and the amide of the protein partly restrain the formation of hydrogen bonds within the helical structure when the copolymer concentration is higher at pH 6.5 and 10.5. PMID:16153115

Liang, Li; Yao, Ping; Jiang, Ming

2005-01-01

176

Transformation-associated changes in sphingolipid metabolism sensitize cells to lysosomal cell death induced by inhibitors of acid sphingomyelinase.  

PubMed

Lysosomal membrane permeabilization and subsequent cell death may prove useful in cancer treatment, provided that cancer cell lysosomes can be specifically targeted. Here, we identify acid sphingomyelinase (ASM) inhibition as a selective means to destabilize cancer cell lysosomes. Lysosome-destabilizing experimental anticancer agent siramesine inhibits ASM by interfering with the binding of ASM to its essential lysosomal cofactor, bis(monoacylglycero)phosphate. Like siramesine, several clinically relevant ASM inhibitors trigger cancer-specific lysosomal cell death, reduce tumor growth in vivo, and revert multidrug resistance. Their cancer selectivity is associated with transformation-associated reduction in ASM expression and subsequent failure to maintain sphingomyelin hydrolysis during drug exposure. Taken together, these data identify ASM as an attractive target for cancer therapy. PMID:24029234

Petersen, Nikolaj H T; Olsen, Ole D; Groth-Pedersen, Line; Ellegaard, Anne-Marie; Bilgin, Mesut; Redmer, Susanne; Ostenfeld, Marie S; Ulanet, Danielle; Dovmark, Tobias H; Lønborg, Andreas; Vindeløv, Signe D; Hanahan, Douglas; Arenz, Christoph; Ejsing, Christer S; Kirkegaard, Thomas; Rohde, Mikkel; Nylandsted, Jesper; Jäättelä, Marja

2013-09-01

177

Leaching behavior of heavy metals and transformation of their speciation in polluted soil receiving simulated acid rain.  

PubMed

Heavy metals that leach from contaminated soils under acid rain are of increasing concern. In this study, simulated acid rain (SAR) was pumped through columns of artificially contaminated purple soil. Column leaching tests and sequential extraction were conducted for the heavy metals Cu, Pb, Cd, and Zn to determine the extent of their leaching as well as to examine the transformation of their speciation in the artificially contaminated soil columns. Results showed that the maximum leachate concentrations of Cu, Pb, Cd, and Zn were less than those specified in the Chinese Quality Standards for Groundwater (Grade IV), thereby suggesting that the heavy metals that leached from the polluted purple soil receiving acid rain may not pose as risks to water quality. Most of the Pb and Cd leachate concentrations were below their detection limits. By contrast, higher Cu and Zn leachate concentrations were found because they were released by the soil in larger amounts as compared with those of Pb and Cd. The differences in the Cu and Zn leachate concentrations between the controls (SAR at pH 5.6) and the treatments (SAR at pH 3.0 and 4.5) were significant. Similar trends were observed in the total leached amounts of Cu and Zn. The proportions of Cu, Pb, Cd, and Zn in the EXC and OX fractions were generally increased after the leaching experiment at three pH levels, whereas those of the RES, OM, and CAR fractions were slightly decreased. Acid rain favors the leaching of heavy metals from the contaminated purple soil and makes the heavy metal fractions become more labile. Moreover, a pH decrease from 5.6 to 3.0 significantly enhanced such effects. PMID:23185399

Zheng, Shun-an; Zheng, Xiangqun; Chen, Chun

2012-01-01

178

Leaching Behavior of Heavy Metals and Transformation of Their Speciation in Polluted Soil Receiving Simulated Acid Rain  

PubMed Central

Heavy metals that leach from contaminated soils under acid rain are of increasing concern. In this study, simulated acid rain (SAR) was pumped through columns of artificially contaminated purple soil. Column leaching tests and sequential extraction were conducted for the heavy metals Cu, Pb, Cd, and Zn to determine the extent of their leaching as well as to examine the transformation of their speciation in the artificially contaminated soil columns. Results showed that the maximum leachate concentrations of Cu, Pb, Cd, and Zn were less than those specified in the Chinese Quality Standards for Groundwater (Grade IV), thereby suggesting that the heavy metals that leached from the polluted purple soil receiving acid rain may not pose as risks to water quality. Most of the Pb and Cd leachate concentrations were below their detection limits. By contrast, higher Cu and Zn leachate concentrations were found because they were released by the soil in larger amounts as compared with those of Pb and Cd. The differences in the Cu and Zn leachate concentrations between the controls (SAR at pH 5.6) and the treatments (SAR at pH 3.0 and 4.5) were significant. Similar trends were observed in the total leached amounts of Cu and Zn. The proportions of Cu, Pb, Cd, and Zn in the EXC and OX fractions were generally increased after the leaching experiment at three pH levels, whereas those of the RES, OM, and CAR fractions were slightly decreased. Acid rain favors the leaching of heavy metals from the contaminated purple soil and makes the heavy metal fractions become more labile. Moreover, a pH decrease from 5.6 to 3.0 significantly enhanced such effects.

Zheng, Shun-an; Zheng, Xiangqun; Chen, Chun

2012-01-01

179

Suberoylanilide hydroxamic acid (SAHA) inhibits EGF-induced cell transformation via reduction of cyclin D1 mRNA stability  

PubMed Central

Suberoylanilide hydroxamic acid (SAHA) inhibiting cancer cell growth has been associated with its down-regulation of cyclin D1 protein expression at transcription level or translation level. Here, we have demonstrated that SAHA inhibited EGF-induced Cl41 cell transformation via the decrease of cyclin D1 mRNA stability and induction of G0/G1 growth arrest. We found that SAHA treatment resulted in the dramatic inhibition of EGF-induced cell transformation, cyclin D1 protein expression and induction of G0/G1 growth arrest. Further studies showed that SAHA downregulation of cyclin D1 was only observed with endogenous cyclin D1, but not with reconstitutionally expressed cyclin D1 in the same cells, excluding the possibility of SAHA regulating cyclin D1 at level of protein degradation. Moreover, SAHA inhibited EGF-induced cyclin d1 mRNA level, whereas it did not show any inhibitory effect on cyclin D1 promoter-driven luciferase reporter activity under the same experimental conditions, suggesting that SAHA may decrease cyclin D1 mRNA stability. This notion was supported by the results that treatment of cells with SAHA decreased the half-life of cyclin D1 mRNA from 6.95 h to 2.57 h. Consistent with downregulation of cyclin D1 mRNA stability, SAHA treatment also attenuated HuR expression, which has been well-characterized as a positive regulator of cyclin D1 mRNA stability. Thus, our study identifies a novel mechanism responsible for SAHA inhibiting cell transformation via decreasing cyclin D1 mRNA stability and induction of G0/G1 growth arrest in Cl41 cells.

Zhang, Jingjie; Ouyang, Weiming; Li, Jingxia; Zhang, Dongyun; Yu, Yonghui; Wang, York; Li, Xuejun; Huang, Chuanshu

2013-01-01

180

[Influence of b and giberellic acid on the transformation of lipids in glucids during the germination of sunflower seeds (author's transl)].  

PubMed

The transformation of total lipids in carbohydrates and the evolution of the fatty acids, constituents of these lipids, during the germination of sunflower seeds, soaked previously in B and giberellic acid solutions, was studied. An inverse relationship between the total content in fatty acids and sugars of the blank (H20) and AG3 treatments was found. However, in the whole germinative process, the B and B + AG3 treatments changed strongly the carbohydrates metabolism and no significant differences of those constituents was observed. The content in fatty acids in the two last treatments showed a great stability and the percentage of these components remained fixed in all the treatments. PMID:725227

Jiménez, F; Donaire, J P; Aguilar, A

1978-09-01

181

Modulation of amino acid metabolism in transformed tobacco plants deficient in Fd-GOGAT  

Microsoft Academic Search

Tobacco (Nicotiana tabacum) plants expressing a\\u000a \\u000a partial ferredoxin-dependent glutamine-2-oxoglutarate aminotransferase (Fd-GOGAT) cDNA in the antisense orientation under\\u000a the control of the 35S promoter, were used to study the metabolism of amino acids, 2-oxoglutarate and ammonium following the\\u000a transition from CO2 enrichment (where photorespiration is inhibited) to air (where photorespiration is a major process of ammonium production\\u000a in leaves). The leaves

S. Ferrario-Méry; A. Suzuki; C. Kunz; M. H. Valadier; Y. Roux; B. Hirel; C. H. Foyer

2000-01-01

182

An Unusual Abscisic Acid and Gibberellic Acid Synergism Increases Somatic Embryogenesis, Facilitates Its Genetic Analysis and Improves Transformation in Medicago truncatula  

PubMed Central

Somatic embryogenesis (SE) can be readily induced in leaf explants of the Jemalong 2HA genotype of the model legume Medicago truncatula by auxin and cytokinin, but rarely in wild-type Jemalong. Gibberellic acid (GA), a hormone not included in the medium, appears to act in Arabidopsis as a repressor of the embryonic state such that low ABA (abscisic acid): GA ratios will inhibit SE. It was important to evaluate the GA effect in M. truncatula in order to formulate generic SE mechanisms, given the Arabidopsis information. It was surprising to find that low ABA:GA ratios in M. truncatula acted synergistically to stimulate SE. The unusual synergism between GA and ABA in inducing SE has utility in improving SE for regeneration and transformation in M. truncatula. Expression of genes previously shown to be important in M. truncatula SE was not increased. In investigating genes previously studied in GA investigations of Arabidopsis SE, there was increased expression of GA2ox and decreased expression of PICKLE, a negative regulator of SE in Arabidopsis. We suggest that in M. truncatula there are different ABA:GA ratios required for down-regulating the PICKLE gene, a repressor of the embryonic state. In M. truncatula it is a low ABA:GA ratio while in Arabidopsis it is a high ABA:GA ratio. In different species the expression of key genes is probably related to differences in how the hormone networks optimise their expression.

Nolan, Kim E.; Song, Youhong; Liao, Siyang; Saeed, Nasir A.; Zhang, Xiyi; Rose, Ray J.

2014-01-01

183

Hydrolysis of 4-Hydroxybenzoic Acid Esters (Parabens) and Their Aerobic Transformation into Phenol by the Resistant Enterobacter cloacae Strain EM  

PubMed Central

Enterobacter cloacae strain EM was isolated from a commercial dietary mineral supplement stabilized by a mixture of methylparaben and propylparaben. It harbored a high-molecular-weight plasmid and was resistant to high concentrations of parabens. Strain EM was able to grow in liquid media containing similar amounts of parabens as found in the mineral supplement (1,700 and 180 mg of methyl and propylparaben, respectively, per liter or 11.2 and 1.0 mM) and in very high concentrations of methylparaben (3,000 mg liter?1, or 19.7 mM). This strain was able to hydrolyze approximately 500 mg of methyl-, ethyl-, or propylparaben liter?1 (3 mM) in less than 2 h in liquid culture, and the supernatant of a sonicated culture, after a 30-fold dilution, was able to hydrolyze 1,000 mg of methylparaben liter?1 (6.6 mM) in 15 min. The first step of paraben degradation was the hydrolysis of the ester bond to produce 4-hydroxybenzoic acid, followed by a decarboxylation step to produce phenol under aerobic conditions. The transformation of 4-hydroxybenzoic acid into phenol was stoichiometric. The conversion of approximately 500 mg of parabens liter?1 (3 mM) to phenol in liquid culture was completed within 5 h without significant hindrance to the growth of strain EM, while higher concentrations of parabens partially inhibited its growth.

Valkova, Nelly; Lepine, Francois; Valeanu, Loredana; Dupont, Maryse; Labrie, Louisette; Bisaillon, Jean-Guy; Beaudet, Rejean; Shareck, Francois; Villemur, Richard

2001-01-01

184

Collection of VLE data for acid gas-alkanolamine systems using Fourier transform infrared spectroscopy  

SciTech Connect

The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. Inadequate data for vapor -- liquid equilibrium (VLE) hinder the industry from converting operations to more energy efficient amine mixtures and conserving energy. Some energy reductions have been realized in the past decade by applying such amine systems as hindered'' amines, methyldiethanolamine (MDEA), and MDEA based amine mixtures. However, the lack of reliable and accurate fundamental VLE data impedes the commercial application of these more efficient alkanolamine systems. The first project objective is to improve the accuracy of vapor -- liquid equilibrium measurements at low hydrogen sulfide concentrations. The second project objective is to measure the VLE for amine mixtures. By improving the accuracy of the VLE measurements on MDEA and mixtures with other amines, energy saving can be quickly and confidently implemented in the many existing absorption units already in use. If about 25% of the existing 95.3 billion SCFD gas purification capacity is converted to these new amine systems, the energy savings are estimated to be about 3 {times} 10{sup 14} BTU/yr.

Bullin, J.A.; Frazier, R.E.

1991-09-01

185

Transformation of isoflavone phytoestrogens during the fermentation of soymilk with lactic acid bacteria and bifidobacteria.  

PubMed

In the present study, soymilk is fermented with lactic acid bacteria (Streptococcus thermophilus BCRC 14085, Lactobacillus acidophilus BCRC 14079) and bifidobacteria (Bifidobacterium infantis BCRC 14633, B. longum B6) individually, and in combination. The change in the content of various isoflavones (aglycones, glucoside, acetyl- and malonyl-glucosides) and the beta-glucosidase activity in soymilk during fermentation is investigated. It is observed that fermented soymilk contains a lower total isoflavone content (81.94-86.61 microg/ml) than soymilk without fermentation (87.61 microg/ml). Regardless of starter organism employed, fermentation causes a major reduction in the contents of glucoside, malonylglucoside and acetylglucoside isoflavones along with a significant increase of aglycone isoflavones content. The level of change in the content of various isoflavones and beta-glucosidase activity after fermentation varies with the starter organism. Among all the fermented soymilks tested, soymilk fermented with S. thermophilus showed the highest beta-glucosidase activity and the greatest increase in the contents of aglycones. The percentage of daidzein, genistein and glycitein to total isoflavone content in S. thermophilus-fermented soymilk increases from an initial 14.24%, 6.89% and 2.45%, respectively, to 36.20%, 28.80% and 12.44% after 24h of fermentation. Finally, the increase of aglycones and decrease of glucoside isoflavones during fermentation coincides with the increase of beta-glucosidase activity observed in fermented soymilk. PMID:16943081

Chien, Hsiang-Lin; Huang, Hui-Yu; Chou, Cheng-Chun

2006-12-01

186

Selection of calibration set samples in determination of olive oil acidity by partial least squares–attenuated total reflectance–Fourier transform infrared spectroscopy  

Microsoft Academic Search

A chemometric method has been applied for the determination of the free fatty acid (FFA) concentration in commercial olive oil samples of different types an origins by using Fourier transform infrared spectroscopy (FTIR) attenuated total reflectance (ATR) measurements. Different methods for selecting the training set, including hierarchical cluster analysis, were applied and compared. The prediction capabilities of partial least squares

Fernando A Iñón; José M Garrigues; Salvador Garrigues; Antonio Molina; Miguel de la Guardia

2003-01-01

187

Effect of E h on the rate and mechanism of the transformation of goethite into hematite in a high temperature acid leach process  

Microsoft Academic Search

Conversion of goethite into hematite is the critical reaction for high temperature acid leaching of nickel laterite ores. The transformation occurs by dissolution of goethite and precipitation of hematite. It is shown that the dissolution stage of this process may be faster or slower than the precipitation stage, depending upon the oxidation potential of the solution. At lower potentials in

G. P. Tindall; D. M. Muir

1998-01-01

188

Metabolic transformation of DMBA-induced carcinogenesis and inhibitory effect of salvianolic acid b and breviscapine treatment.  

PubMed

Oral cancer typically develops from hyperplasia through dysplasia to carcinoma with a multistep process of carcinogenesis involving genetic alterations resulting in aberrant cellular appearance, deregulated cell growth, and carcinoma. The metabolic transformation during the process of oral carcinogenesis and its implications for cancer therapy have not been extensively investigated. Here, we report a metabonomic study on a classical model of 7,12-dimethylbenz(a)anthracene (DMBA)-induced oral carcinogenesis in hamsters to delineate characteristic metabolic transformation during the carcinogenesis using gas chromatography time-of-flight mass spectrometry (GC-TOF MS). Salvianolic acid B (Sal-B), isolated from Salvia miltiorrhiza Bge, and Breviscapine, a flavonoid isolated from Herba Erigerontis, were used to treat the hamsters exposed to DMBA to investigate the molecular mechanism of the inhibitory effect of the two agents on oral carcinogenesis. The dynamic changes of serum metabolic profiles indicated that both Sal-B and Breviscapine were able to attenuate DMBA-induced metabolic perturbation, which is consistent with the histopathological findings that Sal-B and Breviscapine significantly decreased the squamous cell carcinoma (SCC) incidence in the two treatment groups. Significant alterations of key metabolic pathways, including elevated glutaminolysis and glycolysis, and decreased cholesterol and myo-inositol metabolism, were observed in the DMBA-induced model group, which were attenuated or normalized by Sal-B or Breviscapine treatment. Elevated inflammation and tumor angiogenesis at gene and metabolite expression levels were also observed in DMBA-induced oral dysplasia and SCC but were attenuated or normalized by Sal-B and Breviscapine along with significantly decreased incidences of SCC formation. PMID:22115128

Wei, Jie; Xie, Guoxiang; Ge, Shuyun; Qiu, Yunping; Liu, Wei; Lu, Aiping; Chen, Tianlu; Li, Houkai; Zhou, Zengtong; Jia, Wei

2012-02-01

189

Transformation of 4-cholesten-3-one and 7 alpha-hydroxy-4-cholesten-3-one into cholestanol and bile acids in cerebrotendinous xanthomatosis  

SciTech Connect

In order to determine whether cholestanol and bile acids are derived from the same precursor, key intermediates of both biosynthetic pathways beyond cholesterol were administered intravenously to a patient with cerebrotendinous xanthomatosis and to a control subject. After pulse-labeling with (4-/sup 14/C)4-cholesten-3-one and (G-/sup 3/H)7 alpha-hydroxy-4-cholesten-3-one, cholestanol, cholesterol, and the two primary bile acids, cholic acid and chenodeoxycholic acid were isolated from specimens of bile. In other studies, the in vitro formation of 4-cholesten-3-one from cholesterol was measured in hepatic microsomal fractions prepared from a subject with cerebrotendinous xanthomatosis and from 3 control individuals. In all subjects, cholic acid and chenodeoxycholic acid were labeled with tritium, but neither cholesterol nor cholestanol contained this isotope. In contrast, /sup 14/C was detected in the cholestanol fraction with trace amounts in chenodeoxycholic acid, cholic acid, and cholesterol. The results indicate that 4-cholesten-3-one was converted primarily into cholestanol and 7 alpha-hydroxy-4-cholesten-3-one into cholic acid and chenodeoxycholic acid. Neither ketonic steroid was transformed into cholesterol. The increased production of cholestanol in cerebrotendinous xanthomatosis may be accounted for by enhanced hepatic formation of 4-cholesten-3-one. 7 alpha-Hydroxy-4-cholesten-3-one is a precursor of bile acids, but not of cholestanol.

Salen, G.; Shefer, S.; Tint, G.S.

1984-08-01

190

Inhibition of the growth of 12V-ras-transformed rat fibroblasts by acetylsalicylic acid correlates with inhibition of NF-kappa B.  

PubMed

Epidemiological studies have demonstrated a correlation between regular aspirin (acetylsalicylic acid; ASA) use and a decreased risk for the development of cancer. We here show that ASA inhibits the growth of 12V-ras-transformed rat fibroblasts in vitro at pharmacological concentrations. This effect appeared to be unrelated to inhibition of cyclooxygenase, since other cyclooxygenase inhibitors did not inhibit cell growth. A number of nuclear transcription factors have been implicated as mediators of transformation. ASA has recently been reported to inhibit the activation of one such factor, NF-kappa B. We found that NF-kappa B binding activity was decreased in ASA-treated 12V-ras-transformed cells. Inhibition of NF-kappa B activation was not due to a general inhibitory effect, since AP-1 binding activity was not affected. We conclude that ASA inhibits the growth of 12V-ras-transformed fibroblasts, possibly via inhibition of NF-kappa B. PMID:9147613

Ljungdahl, S; Shoshan, M C; Linder, S

1997-01-01

191

Hydroisomerization and hydrocracking of alkanes. 7. Influence of the balance between acid and hydrogenating functions on the transformation of n-decane on PtHY catalysts  

SciTech Connect

The transformation of n-decane was studied at 473 K, 101 kPa and pH{sub 2}/p{sub n-decane} = 9 on a series of PtHY catalysts containing from 0.02 to 1.5 wt% platinum and with Si/Al atomic ratios of 3, 9, or 35. The ratio between the number of accessible Pt atoms and the number of acid sites on which the heat of ammonia adsorption is greater than 100 kJ mol{sup -1} (n{sub Pt}/n{sub A}) was chosen for characterizing the balance between the hydrogenating and the acid functions. The activities, stabilities, and selectivities of the catalysts are definitely governed by this balance. For low values of N{sub Pt}/n{sub A} (<0.03), the activity per acid site is low, the deactivation is rapid and n-decane leads directly to all the isomerization and cracking products. For high values ({ge}0.17) the activity per acid sites is maximal, the deactivation is very slow and n-decane transforms successively into monobranched isomers, dibranched isomers, and tribranched isomers plus cracking products. In this latter case the catalyst can be considered as an ideal bifunctional catalyst, namely a catalyst on which only one transformation of the alkene intermediates on the acid sites can occur during their diffusion from the platinum sites on which they are generated to those on which they are hydrogenated. Therefore the reaction scheme of n-decane transformation matches the reaction scheme of olefinic intermediates. From the product distribution established on ideal catalysts the mechanism of the transformation of olefinic intermediates can be deduced. Branching isomerization occurs through protonated cyclopropane and cyclobutane intermediates. 29 refs., 9 figs., 5 tabs.

Alvarez, F.; Ribeiro, F.R. [Instituto Superior Tecnico, Lisboa Codex (Portugal)] [Instituto Superior Tecnico, Lisboa Codex (Portugal); Perot, G.; Thomazeau, C. [Universite de Poitiers (France)] [Universite de Poitiers (France)

1996-09-01

192

Cleft lip with or without cleft palate: Associations with transforming growth factor alpha and retinoic acid receptor loci  

SciTech Connect

The first association study of cleft lip with or without cleft palate (CL/P), with candidate genes, found an association with the transforming growth-factor alpha (TGFA) locus. This finding has since been replicated, in whole or in part, in three independent studies. Here the authors extend their original analysis of the TGFA TaqI RFLP to two other TGFA RFLPs and seven other RFLPs at five candidate genes in 117 nonsyndromic cases of CL/P and 113 controls. The other candidate genes were the retinoic acid receptor (RARA), the bcl-2 oncogene, and the homeobox genes 2F, 2G, and EN2. Significant associations with the TGFA TaqI and BamHI RFLPs were confirmed, although associations of clefting with previously reported haplotypes did not reach significance. Of particular interest, in view of the known teratogenic role of retinoic acid, was a significant association with the RARA PstI RFLP (P = .016; not corrected for multiple testing). The effect on risk of the A2 allele appears to be additive, and although the A2A2 homozygote only has an odds ratio of about 2 and recurrence risk to first-degree relatives ([lambda][sub 1]) of 1.06, because it is so common it may account for as much as a third of the attributable risk of clefting. There is no evidence of interaction between the TGFA and RARA polymorphisms on risk, and jointly they appear to account for almost half the attributable risk of clefting. 43 refs., 1 fig., 4 tabs.

Chenevix-Trench, G.; Jones, K. (Queensland Inst. of Medical Research (Australia) Univ. of Queensland (Australia)); Green, A.C.; Duffy, D.L.; Martin, N.G. (Queensland Inst. of Medical Research (Australia))

1992-12-01

193

Fourier transform-ion cyclotron resonance study of the gas-phase acidities of germane and methylgermane; Bond dissociation energy of germane.  

PubMed

An accurate gas-phase acidity for germane (enthalpy scale, equivalent to the proton affinity of GeH3 (-)), ?H acid (o)(GeH4) = 1502.0 ± 5.1 kJ mol(-1), is obtained by constructing a consistent acidity ladder between GeH4, and H2S by using Fourier transform-ion cyclotron resonance spectrometry, and 0 and 298.15 K values for the first bond dissociation energy of GeH4 are proposed: D0 (o)(H3Ge-H) = 352 ± 9 kJ mol(-1); D (o)(H3Ge-H) = 358 ± 9 kJ mol(-1), respectively. These results are compared with experimental and theoretical data reported in the literature. Methylgermane was found to be a weaker acid than germane by approximately 35 kJ mol(-1): ?H acid (o) = 1536.6 kJ mol(-1). PMID:24234744

Decouzon, M; Gal, J F; Gayraud, J; Maria, P C; Vaglio, G A; Volpe, P

1993-01-01

194

Sphingomyelin and sphingomyelin synthase (SMS) in the malignant transformation of glioma cells and in 2-hydroxyoleic acid therapy  

PubMed Central

The mechanism of action of 2-hydroxyoleic acid (2OHOA), a potent antitumor compound, has not yet been fully elucidated. Here, we show that human cancer cells have markedly lower levels of sphingomyelin (SM) than nontumor (MRC-5) cells. In this context, 2OHOA treatment strongly augments SM mass (4.6-fold), restoring the levels found in MRC-5 cells, while a loss of phosphatidylethanolamine and phosphatidylcholine is observed (57 and 30%, respectively). The increased SM mass was due to a rapid and highly specific activation of SM synthases (SMS). This effect appeared to be specific against cancer cells as it did not affect nontumor MRC-5 cells. Therefore, low SM levels are associated with the tumorigenic transformation that produces cancer cells. SM accumulation occurred at the plasma membrane and caused an increase in membrane global order and lipid raft packing in model membranes. These modifications would account for the observed alteration by 2OHOA in the localization of proteins involved in cell apoptosis (Fas receptor) or differentiation (Ras). Importantly, SMS inhibition by D609 diminished 2OHOA effect on cell cycle. Therefore, we propose that the regulation of SMS activity in tumor cells is a critical upstream event in 2OHOA antitumor mechanism, which also explains its specificity for cancer cells, its potency, and the lack of undesired side effects. Finally, the specific activation of SMS explains the ability of this compound to trigger cell cycle arrest, cell differentiation, and autophagy or apoptosis in cancer cells.

Barcelo-Coblijn, Gwendolyn; Martin, Maria Laura; de Almeida, Rodrigo F. M.; Noguera-Salva, Maria Antonia; Marcilla-Etxenike, Amaia; Guardiola-Serrano, Francisca; Luth, Anja; Kleuser, Burhard; Halver, John E.; Escriba, Pablo V.

2011-01-01

195

Generation and function of immunosuppressive human and murine CD8+ T cells by transforming growth factor-? and retinoic acid  

PubMed Central

The intestinal immune system is constantly challenged by foreign antigens and commensal bacteria. Therefore, proper control of the intestinal microenvironment is required. One important arm of this regulatory network consists of regulatory T cells. In contrast to CD4+ Foxp3+ regulatory T cells, which have been well characterized, immunomodulatory CD8+ T cells that express Foxp3 are less well defined in terms of their generation and function. Failures of these regulatory mechanisms contribute to the development of inflammatory bowel disease. In this study we demonstrate that the frequency of CD8+ Foxp3+ T cells is reduced in the peripheral blood of patients with ulcerative colitis. As these cells might play a currently underestimated role in the maintenance of intestinal homeostasis, we have investigated human and murine CD8+ Foxp3+ T cells generated by stimulating naive CD8+ T cells in the presence of transforming growth factor-? and retinoic acid, mediators that are abundantly produced in the intestinal mucosa. These CD8+ Foxp3+ fully competent regulatory T cells show strong expression of regulatory molecules CD25, Gpr83 and CTLA-4 and exhibit cell–cell contact-dependent immunosuppressive activity in vitro. Our study illustrates a previously unappreciated critical role of CD8+ Foxp3+ T cells in controlling potentially dangerous T cells and in the maintenance of intestinal homeostasis.

Fleissner, Diana; Frede, Annika; Knott, Markus; Knuschke, Torben; Geffers, Robert; Hansen, Wiebke; Dobos, Gustav; Langhorst, Jost; Buer, Jan; Westendorf, Astrid M

2011-01-01

196

Generation and function of immunosuppressive human and murine CD8+ T cells by transforming growth factor-? and retinoic acid.  

PubMed

The intestinal immune system is constantly challenged by foreign antigens and commensal bacteria. Therefore, proper control of the intestinal microenvironment is required. One important arm of this regulatory network consists of regulatory T cells. In contrast to CD4(+) Foxp3(+) regulatory T cells, which have been well characterized, immunomodulatory CD8(+) T cells that express Foxp3 are less well defined in terms of their generation and function. Failures of these regulatory mechanisms contribute to the development of inflammatory bowel disease. In this study we demonstrate that the frequency of CD8(+) Foxp3(+) T cells is reduced in the peripheral blood of patients with ulcerative colitis. As these cells might play a currently underestimated role in the maintenance of intestinal homeostasis, we have investigated human and murine CD8(+) Foxp3(+) T cells generated by stimulating naive CD8(+) T cells in the presence of transforming growth factor-? and retinoic acid, mediators that are abundantly produced in the intestinal mucosa. These CD8(+) Foxp3(+) fully competent regulatory T cells show strong expression of regulatory molecules CD25, Gpr83 and CTLA-4 and exhibit cell-cell contact-dependent immunosuppressive activity in vitro. Our study illustrates a previously unappreciated critical role of CD8(+) Foxp3(+) T cells in controlling potentially dangerous T cells and in the maintenance of intestinal homeostasis. PMID:21711349

Fleissner, Diana; Frede, Annika; Knott, Markus; Knuschke, Torben; Geffers, Robert; Hansen, Wiebke; Dobos, Gustav; Langhorst, Jost; Buer, Jan; Westendorf, Astrid M

2011-09-01

197

A high-throughput screen for hyaluronic acid accumulation in recombinant Escherichia coli transformed by libraries of engineered sigma factors.  

PubMed

Hyaluronic acid (HA) is an important biomaterial with functional medical and cosmetic applications. As its synthesis has been recently reported in recombinant bacteria, it is of interest to develop a high throughput screening method for the rapid isolation of HA accumulating strains transformed by combinatorial libraries. Here we report a novel two-step screening strategy to select for better HA-producing recombinant Escherichia coli strains transformed by mutation libraries of rpoD and rpoS, coding for the sigma(D) and sigma(S) factors of the RNA polymerase, respectively. The first screen, based on translucent colony morphology identification, was used to qualitatively distinguish HA-producing strains on agar plates from non-HA producing strains that exhibit dense colony morphology. The second screen was based on the photometric measurement of an alcian blue staining solution that precipitates with HA, creating an inverse relationship between HA concentration and alcian blue absorbance. The color attenuation fitted a second-order polynomial between HA concentration and OD(540) absorbance. Using the alcian blue absorbance quantification, 74 translucent colonies from the HA-rpoD library and 78 translucent colonies from the HA-rpoS library were isolated and cultured for optimal strain selection. Three representative superior recombinants with high, medium and low increase of HA accumulation, respectively, were identified by the screen from the HA-rpoD and HA-rpoS mutant library. Further flask culture confirmed that results of the library screen were reliable and the superior recombinant D72 highly accumulated HA of 561.4 mg/L with a productivity of approximately 265 mg HA/g dry cell. Sequencing results showed that the mutant rpoD gene in D72 is in a truncated protein that lacks the conserved regions 3 and 4 of the sigma(D). Generally, this two-step high throughput screen presents a promising strategy for selecting superior HA-producing strains from large scale mutation libraries. PMID:18500764

Yu, Huimin; Tyo, Keith; Alper, Hal; Klein-Marcuschamer, Daniel; Stephanopoulos, Gregory

2008-11-01

198

Ambient formic acid in southern California air: A comparison of two methods, Fourier transform infrared spectroscopy and alkaline trap-liquid chromatography with UV detection  

SciTech Connect

Formic acid is an ubiquitous component of urban smog. Sources of formic acid in urban air include direct emissions from vehicles and in situ reaction of ozone with olefins. Ambient levels of formic acid in southern California air were first measured some 15 years ago by Hanst et al. using long-path Fourier transform infrared spectroscopy (FTIR). All subsequent studies of formic acid in the Los Angeles area have involved the use of two methods, either FTIR or collection on alkaline traps followed by gas chromatography, ion chromatography, or liquid chromatography analysis with UV detection, ATLC-UV. The Carbon Species Methods Comparison Study (CSMCS), a multilaboratory air quality study carried out in August 1986 at a southern California smog receptor site, provided an opportunity for direct field comparison of the FTIR and alkaline trap methods. The results of the comparison are presented in this brief report.

Grosjean, D. (DGA, Inc., Ventura, CA (USA)); Tuazon, E.C. (Univ. of California, Riverside (USA)); Fujita, E. (California Air Resources Board, Sacramento (USA))

1990-01-01

199

Retinoic acid mimics transforming growth factor beta in the regulation of human immunodeficiency virus expression in monocytic cells.  

PubMed Central

Retinoic acid (RA) exerts potent suppressive and upregulatory effects on human immunodeficiency virus (HIV) expression in mononuclear phagocytes, strikingly similar to the effects of the cytokine transforming growth factor beta (TGF-beta). RA significantly inhibited phorbol ester-mediated, but not tumor necrosis factor alpha-mediated, induction of HIV transcription in the chronically infected promonocytic U1 cell line. RA and TGF-beta also completely suppressed the induction of virus production in U1 cells by interleukin 6 alone or in combination with glucocorticoids, which predominantly upregulate virus expression at the posttranscriptional level. Despite the close parallel to TGF-beta-induced effects, no evidence was obtained that RA mediated its effect by inducing secretion of active TGF-beta 1, -beta 2, or -beta 3. As with chronically infected U1 cells, similar inhibitory effects were also observed in primary monocyte-derived macrophages previously infected with HIV and then exposed to either RA or TGF-beta. In contrast, stimulation of monocyte-derived macrophages or U937 cells (the parental cell line of U1) with either RA or TGF-beta prior to in vitro infection resulted in the enhancement of virus production. Given the already successful use of retinoids in the treatment of several malignancies and the present demonstration of their capability of blocking the induction of HIV expression in infected mononuclear phagocytes, it would be of interest to pursue the potential role of this class of compounds in the development of strategies aimed at the pharmacologic regulation of HIV expression.

Poli, G; Kinter, A L; Justement, J S; Bressler, P; Kehrl, J H; Fauci, A S

1992-01-01

200

Asiatic acid attenuates cardiac hypertrophy by blocking transforming growth factor-?1-mediated hypertrophic signaling in vitro and in vivo.  

PubMed

Cardiac hypertrophy is a major cause of morbidity and mortality worldwide. Transforming growth factor-?1 (TGF-?1) signaling has been considered as a trigger causally contributing to pathological cardiac hypertrophy. Asiatic acid (AA) is a triterpenoid compound extracted from Centella asiatica and exhibits a variety of pharmacological effects. In this study, we investigated the anti-hypertrophic effects and mechanisms of action of AA in a TGF-?1-stimulated hypertrophic response using cultured neonatal cardiomyocytes in vitro and in a mouse model of cardiac hypertrophy induced by pressure overload in vivo. Treatment with AA markedly attenuated the TGF-?1-induced hypertrophic responses of cardiomyocytes as reflected by reduction in the cardiomyocyte surface area and the inhibition of atrial natriuretic peptide (ANP) mRNA expression. The protective effects of AA on hypertrophic cardiomyocytes were associated with the blocking of p38 and extracellular signal?regulated kinase (ERK)1/2 phosphorylation and the reduction of nuclear factor-?B (NF-?B) binding activity. In vivo experiments indicated that the administration of AA prevented cardiac hypertrophy and dysfunction induced by pressure overload. It was found that AA markedly reduced the excessive production of TGF-?1 in the hypertrophic myocardium, blocked the phosphorylation of p38 and ERK1/2 and inhibited the activation of NF-?B. Our data suggest that AA may be a novel therapeutic agent for cardiac hypertrophy. The inhibition of TGF-?1?mediated hypertrophic signaling may be the mechanism through which AA prevents cardiac hypertrophy. PMID:24827470

Si, Linjie; Xu, Jing; Yi, Chenlong; Xu, Xiaohan; Wang, Fang; Gu, Weijuan; Zhang, Yuqing; Wang, Xiaowei

2014-08-01

201

Naphthenic acids as indicators of crude oil biodegradation in soil, based on semi-quantitative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.  

PubMed

Crude oil contaminated soil cores were collected from a basin that contained oily solids left from three decades of oil production. Hydrocarbon biomarker analyses revealed that the soil extracts were moderately biodegraded compared with the non-degraded source oil. The degree of biodegradation also decreased with core depth (7 cm to 1 m). These data were correlated to compositional changes observed in acidic NSO-compounds that were selectively ionized and mass resolved by negative ion electrospray Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). Among the NSO-compounds ionized, the increase in naphthenic acid concentration (e.g., acyclic and alicyclic carboxylic acids) best correlated with the increase in biodegradation (e.g., from non-degraded to moderately degraded) as determined by the hydrocarbon biomarker analyses. The most biodegraded surface extracts (7 cm) exhibited an 80% increase in the abundance of acids relative to the source oil. Use of an internal standard allowed the semi-quantitative determination of the total naphthenic acid concentration, which decreased significantly (P < 0.05) with soil depth. Furthermore, the shift to higher double bond equivalents (DBEs), from acyclic to alicyclic acids, indicated that the increase in acids in the soil extracts was predominantly due to biotic processes. This work demonstrates the potential of ESI FT-ICR MS as a semi-quantitative tool to monitor the production of naphthenic acids during crude oil biotransformation in the environment. PMID:19003816

Hughey, Christine A; Minardi, Carina S; Galasso-Roth, Samantha A; Paspalof, George B; Mapolelo, Mmilili M; Rodgers, Ryan P; Marshall, Alan G; Ruderman, Daniel L

2008-12-01

202

Transformed and immortalized cellular uptake of oligodeoxynucleoside phosphorothioates, 3?-Alkylamino oligodeoxynucleotides, 2?- o-methyl oligoribonucleotides, oligodeoxynucleoside methylphosphonates, and peptide nucleic acids  

Microsoft Academic Search

Direct quantitative comparisons of cellular uptake across a wide variety of analogs and cell types are necessary for the design of oligonucleotide diagnostic and therapeutic applications. This work reports quantitative cellular uptake and nuclear localization of [14C]oligodeoxynucleoside phosphorothioates (PS), 3?-alkylamino Oligodeoxynucleoside phosphodiesters (PO-NH2), 2?-O-methyl oligoribonucleoside phosphodiesters (2OM), peptide nucleic acids (PNA), and oligodeoxynucleoside methylphosphonates (MP) in several transformed or immortalized

Gary D. Gray; Soumitra Basu; Eric Wickstrom

1997-01-01

203

Long-chain polyunsaturated fatty acids interact with nitric oxide, superoxide anion, and transforming growth factor-? to prevent human essential hypertension  

Microsoft Academic Search

Patients with uncontrolled essential hypertension have elevated concentrations of superoxide anion (O2?•), hydrogen peroxide (H2O2), lipid peroxides, endothelin, and transforming growth factor-? (TGF-?) with a simultaneous decrease in endothelial nitric oxide (eNO), superoxide dismutase (SOD), vitamin E, and long-chain polyunsaturated fatty acids (LCPUFAs). Physiological concentrations of angiotensin II activate NAD(P)H oxidase and trigger free radical generation (especially that of O2?•).

U N Das

2004-01-01

204

Novel microwave-assisted synthesis of the immunomodulator organotellurium compound ammonium trichloro(dioxoethylene-O,O')tellurate (AS101).  

PubMed

Ammonium trichloro[1,2-ethanediolato-O,O']-tellurate (AS101) is the most important synthetic Te compound from the standpoint of its biological activity. It is a potent immunomodulator with a variety of potential therapeutic applications and antitumoral action in several preclinical and clinical studies. An experimental design has been used to develop and optimize a novel microwave-assisted synthesis (MAOS) of the AS101. In comparison to the results observed in the literature, refluxing Te(IV) chloride and ethylene glycol in acetonitrile (Method A), or by refluxing Te(IV) chloride and ammonium chloride in ethylene glycol (Method B), it was found that the developed methods in the present work are an effective alternative, because although performance slightly decreases compared to conventional procedures (75% vs. 79% by Method A, and 45% vs. 51% by Method B), reaction times decreased from 4 h to 30 min and from 4 h to 10 min, by Methods A and B respectively. MAOS is proving to be of value in the rapid synthesis of compounds with new and improved biological activities, specially based on the benefit of its shorter reaction times. PMID:24566150

Vázquez-Tato, M Pilar; Mena-Menéndez, Alberto; Feás, Xesús; Seijas, Julio A

2014-01-01

205

Novel Microwave-Assisted Synthesis of the Immunomodulator Organotellurium Compound Ammonium Trichloro(dioxoethylene-O,O?)tellurate (AS101)  

PubMed Central

Ammonium trichloro[1,2-ethanediolato-O,O?]-tellurate (AS101) is the most important synthetic Te compound from the standpoint of its biological activity. It is a potent immunomodulator with a variety of potential therapeutic applications and antitumoral action in several preclinical and clinical studies. An experimental design has been used to develop and optimize a novel microwave-assisted synthesis (MAOS) of the AS101. In comparison to the results observed in the literature, refluxing Te(IV) chloride and ethylene glycol in acetonitrile (Method A), or by refluxing Te(IV) chloride and ammonium chloride in ethylene glycol (Method B), it was found that the developed methods in the present work are an effective alternative, because although performance slightly decreases compared to conventional procedures (75% vs. 79% by Method A, and 45% vs. 51% by Method B), reaction times decreased from 4 h to 30 min and from 4 h to 10 min, by Methods A and B respectively. MAOS is proving to be of value in the rapid synthesis of compounds with new and improved biological activities, specially based on the benefit of its shorter reaction times.

Vazquez-Tato, M. Pilar; Mena-Menendez, Alberto; Feas, Xesus; Seijas, Julio A.

2014-01-01

206

Deep structure of a major subduction back thrust: Magneto-telluric investigations of the Taranaki Fault, New Zealand  

NASA Astrophysics Data System (ADS)

A magneto-telluric (MT) pilot study is used to investigate the Taranaki Fault, a major thrust along the eastern margin of the Taranaki Basin, New Zealand. Analysis of the survey data (MT phase tensor analysis and 2D models), along a 25 km east-west oriented line perpendicular the fault, indicates the Taranaki Fault is the tectonic boundary between major Permian and Mesozoic basement terranes with differing resistivities. Models show the resistivity boundary at the fault dips eastward at about 45° to a depth of at least 12 km. These results suggest that the fault is a major long lived tectonic feature that formed in Mesozoic time during the terrane accretionary phase and has subsequently reactivated during the Cretaceous and Tertiary. At depths less than 5 km, MT models that use constraints from seismic and borehole data show low resistivity sediments extend about 4 km eastward, beneath the tip of the fault. The sedimentary succession beneath the thrust wedge is a petroleum exploration target and with a higher density of MT measurements, a better image of this region may be achieved.

Stagpoole, V. M.; Bennie, S. L.; Bibby, H. M.; Dravitzki, S.; Ingham, M. R.

2009-01-01

207

Ascorbic Acid Kills Epstein-Barr Virus (EBV) Positive Burkitt Lymphoma Cells and EBV Transformed B-Cells in Vitro, but not in Vivo  

PubMed Central

Ascorbic acid has been shown to kill various cancer cell lines at pharmacologic concentrations. We found that Epstein-Barr virus (EBV)-positive Burkitt lymphoma (BL) cells were more susceptible to ascorbic acid-induced cell killing than EBV-negative BL cells or EBV-transformed lymphoblastoid cells (LCLs). Ascorbic acid did not induce apoptosis in any of the tested cells but did induce the production of reactive oxygen species and cell death. Previously, we showed that bortezomib, a proteasome inhibitor, induces cell death in LCLs and EBV-positive BL cells. We found that ascorbic acid is strongly antagonistic for ascorbic acid-induced cell death in LCLs and EBV-positive BL cells. Finally, ascorbic acid did not prolong survival of severe combined immunodefiency mice inoculated with LCLs either intraperitoneally or subcutaneously. Thus, while ascorbic acid was highly effective at killing EBV-positive BL cells and LCLs in vitro, it antagonized cell killing by bortezomib and was ineffective in an animal model.

Shatzer, Amber N.; Espey, Michael G.; Chavez, Mayra; Tu, Hongbin; Levine, Mark; Cohen, Jeffrey I.

2014-01-01

208

Fourier Transform Infrared Spectroscopic Study of the Role of Tartaric Acid in Glass-ionomer Dental Cements  

Microsoft Academic Search

(+) - Tartaric acid is incorporated into glass-ionomer dental cements to control the setting characteristics. FTIR has been used to examine the cements as they set, and has confirmed previous results that (+)-tartaric acid reacts more readily with the glass than does poly(acrylic acid), thereby delaying the setting of the cement. Subsequently, ions released by the glass become available for

J. W. Nicholson; P. J. Brookman; O. M. Lacy; A. D. Wilson

1988-01-01

209

Ascorbic acid kills Epstein-Barr virus positive Burkitt lymphoma cells and Epstein-Barr virus transformed B-cells in vitro, but not in vivo.  

PubMed

Ascorbic acid has been shown to kill various cancer cell lines at pharmacologic concentrations. We found that Epstein-Barr virus (EBV)-positive Burkitt lymphoma (BL) cells were more susceptible to ascorbic acid-induced cell killing than EBV-negative BL cells or EBV-transformed lymphoblastoid cells (LCLs). Ascorbic acid did not induce apoptosis in any of the tested cells but did induce the production of reactive oxygen species and cell death. Previously, we showed that bortezomib, a proteasome inhibitor, induces cell death in LCLs and EBV-positive BL cells. We found that ascorbic acid is strongly antagonistic for bortezomib-induced cell death in LCLs and EBV-positive BL cells. Finally, ascorbic acid did not prolong survival of severe combined immunodefiency mice inoculated with LCLs either intraperitoneally or subcutaneously. Thus, while ascorbic acid was highly effective at killing EBV-positive BL cells and LCLs in vitro, it antagonized cell killing by bortezomib and was ineffective in an animal model. PMID:23067008

Shatzer, Amber N; Espey, Michael Graham; Chavez, Mayra; Tu, Hongbin; Levine, Mark; Cohen, Jeffrey I

2013-05-01

210

In situ fourier transform infrared study of crotyl alcohol, maleic acid, crotonic acid, and maleic anhydride oxidation on a V-P-O industrial catalyst  

SciTech Connect

Crotyl alcohol, maleic acid, crotonic (2-butenoic) acid, and maleic anhydride were fed to an in situ infrared cell at 300/sup 0/C containing a P/V = 1.1 vanadium-phosphorous-oxide (V-P-O) catalyst used for the selective oxidation of n-butane. Crotyl alcohol was used as a mechanistic probe for the formation of reactive olefin species observed during previous n-butane and 1-butene studies. Crotonic acid, maleic acid, and maleic anhydride were fed as probes for the existence of other possible adsorbed intermediates. Olefin species and maleic acid are proposed as possible reaction intermediates in n-butane selective oxidation to maleic anhydride. The involvement of peroxide species in the oxidation of butadiene to maleic acid is also discussed.

Wenig, R.W.; Schrader, G.L.

1987-10-22

211

Transformational Learners: Transformational Teachers  

ERIC Educational Resources Information Center

Transformational learning, according to Mezirow (1981), involves transforming taken-for-granted frames of reference into more discriminating, flexible "habits of mind". In teacher education, transformative learning impacts on the development of students' action theories, self-efficacy and professional attributes. Although considered imperative to…

Jones, Marguerite

2009-01-01

212

The Transformations of Transformations.  

ERIC Educational Resources Information Center

Harris's original idea of transformations has been changed several times in Chomsky's work. This article explicates these transformations, arguing that though their motivations are highly understandable, these transformations are not necessary for understanding the workings of natural languages. (Author/VWL)

Lin, Francis Y.

2000-01-01

213

Simultaneous monitoring of organic acids and sugars in fresh and processed apple juice by Fourier transform infrared-attenuated total reflection spectroscopy.  

PubMed

A combination of Fourier transform infrared spectroscopy (FT-IR) and chemometrics was used as a screening tool for the determination of sugars and organic acids such as sucrose, glucose, fructose, sorbitol, citric acid, and malic acid in processed commercial and extracted fresh apple juices. Prepared samples of synthetic apple juice in different constituent concentration ranges were scanned by attenuated total reflectance (ATR) accessory and the spectral region in the range between 950 and 1500 cm(-1) was selected for calibration model development using partial least squares (PLS) regression and principal component regression (PCR). The calibration models were successfully validated by high-performance liquid chromatography (HPLC) measurements against several commercial juice varieties as well as juice extracted from different apple varieties to provide an overall R2 correlation of 0.998. The present study demonstrates that Fourier transform infrared spectroscopy could be used for rapid and nondestructive determination of multiple constituents in commercial and fresh apple juices. Results indicate this approach to be a rapid and cost-effective tool for routine monitoring of multiple constituents in a fruit juice production facility. PMID:14686782

Irudayaraj, Joseph; Tewari, Jagdish

2003-12-01

214

Evidence for an Ionic Intermediate in the Transformation of Fatty Acid Hydroperoxide by a Catalase-related Allene Oxide Synthase from the Cyanobacterium Acaryochloris marina*  

PubMed Central

Allene oxides are reactive epoxides biosynthesized from fatty acid hydroperoxides by specialized cytochrome P450s or by catalase-related hemoproteins. Here we cloned, expressed, and characterized a gene encoding a lipoxygenase-catalase/peroxidase fusion protein from Acaryochloris marina. We identified novel allene oxide synthase (AOS) activity and a by-product that provides evidence of the reaction mechanism. The fatty acids 18.4?3 and 18.3?3 are oxygenated to the 12R-hydroperoxide by the lipoxygenase domain and converted to the corresponding 12R,13-epoxy allene oxide by the catalase-related domain. Linoleic acid is oxygenated to its 9R-hydroperoxide and then, surprisingly, converted ?70% to an epoxyalcohol identified spectroscopically and by chemical synthesis as 9R,10S-epoxy-13S-hydroxyoctadeca-11E-enoic acid and only ?30% to the 9R,10-epoxy allene oxide. Experiments using oxygen-18-labeled 9R-hydroperoxide substrate and enzyme incubations conducted in H218O indicated that ?72% of the oxygen in the epoxyalcohol 13S-hydroxyl arises from water, a finding that points to an ionic intermediate (epoxy allylic carbocation) during catalysis. AOS and epoxyalcohol synthase activities are mechanistically related, with a reacting intermediate undergoing a net hydrogen abstraction or hydroxylation, respectively. The existence of epoxy allylic carbocations in fatty acid transformations is widely implicated although for AOS reactions, without direct experimental support. Our findings place together in strong association the reactions of allene oxide synthesis and an ionic reaction intermediate in the AOS-catalyzed transformation.

Gao, Benlian; Boeglin, William E.; Zheng, Yuxiang; Schneider, Claus; Brash, Alan R.

2009-01-01

215

FTIR spectroscopic and DFT theoretical study on structure of europium-phosphate-tellurate glasses and glass ceramics  

NASA Astrophysics Data System (ADS)

Glasses and glass ceramics in the ternary xEu 2O 3·(100 - x)[7TeO 2·3P 2O 5] systems with 0 ? x ? 60 mol% have been prepared from melt quenching method. Influence of europium ions on structural behavior in phosphate-tellurate glasses has been investigated using infrared spectroscopy. The addition of high Eu 2O 3 content resulted in gradual depolymerization of the phosphate chains and formation of the EuPO 4 crystalline phase. Presence of the multiple cations of europium and tellurium in the glasses to attract the [PO 4] structural units for compensation of charge yield a competition between these cations. This preference is decided by the potential of ionization of the cations. The changes of the IR spectral features produced by devitrification suggest that this competition explains the drastic reduction of the characteristic features corresponding to the [PO 4] structural units in bandwidth, position and intensity. After the heat treatment applied at 500 °C for 24 h two crystalline phases appear, namely the Te 4P 2O 13 and EuPO 4. The Te 4P 2O 13 crystalline phase is characteristic of the host glass ceramic. The strong affinity of the Eu +3 ions towards the phosphorus groups containing non-bridging oxygen is responsible for the disappearance of Te 4P 2O 13 crystalline phase. We propose a possible structural model of building blocks for the formation of continuous random 7TeO 2·3P 2O 5 glass network used by density functional theory (DFT) calculations. Comparing the theoretical and experimental IR spectral characteristic features, we conclude that the performance of the method/basis sets used on the prediction of the structural data and vibrational modes is good.

Rada, Simona; Culea, Eugen

2009-07-01

216

Hyperfine structure in the rotational spectra of trans-formic acid: Lamb-dip measurements and quantum-chemical calculations  

Microsoft Academic Search

Context. Formic acid, HCOOH, is the simplest organic acid and the first that has been identified in the interstellar medium. Its astrophysical relevance has motivated this spectroscopic study. Aims: The aim of this investigation is to provide very accurate rest frequencies for the trans isomer of HCOOH as well as to improve the spectroscopic and hyperfine parameters available in the

G. Cazzoli; C. Puzzarini; S. Stopkowicz; J. Gauss

2010-01-01

217

A variable-temperature diffuse reflectance infrared fourier transform spectroscopy study of the binding of water and pyridine to the surface of acid-activated metakaolin.  

PubMed

Four metakaolins were prepared by heating a Spanish kaolin at 600, 700, 800, and 900 degrees C for 10 h. Following preliminary optimization, these metakaolins were acid activated in 6 M hydrochloric acid at 90 degrees C for 6 h; the samples calcined at 600, 700, and 800 degrees C produced the highest surface area solids and were selected for further study. Variable-temperature diffuse reflectance infrared Fourier transform spectroscopy analysis of the resulting acid-activated metakaolins (AAMKs) identified a wide range of hydrogen bond strengths in adsorbed water at room temperature. Above 300 degrees C it was possible to fit the broad hydroxyl stretching band to seven contributing components at 3730, 3700, 3655, 3615, 3583, 3424, and 3325 cm(-1). As the sample temperature was increased, the 3730 cm(-1) band increased in intensity as the water hydrogen bonded to AlOHAl was thermally desorbed. The other six bands decreased in intensity. The spectra of adsorbed pyridine indicated the presence of both Brönsted and Lewis acid sites on the surface of the air-dried AAMKs. Preheating the AAMK at 200 degrees C prior to pyridine sorption reduced the number of Brönsted acid sites and increased the number of thermally stable Lewis acid sites. A reduction in the amount of adsorbed pyridine after pretreating the AAMK at 400 degrees C was tentatively attributed to a reduction in surface area. This was reflected in fewer thermally stable Lewis acid sites in the AAMK pretreated at 400 degrees C compared to the number present in the sample pretreated at 200 degrees C. PMID:15751999

Belver, Carolina; Breen, Christopher; Clegg, Francis; Fernandes, Cesar E; Vicente, Miguel A

2005-03-15

218

Hydrothermal syntheses and structures of the uranyl tellurates AgUO 2(HTeO 5) and Pb 2UO 2(TeO 6)  

NASA Astrophysics Data System (ADS)

Two uranyl tellurates, AgUO 2(HTeO 5) ( 1) and Pb 2UO 2(TeO 6) ( 2), were synthesized under hydrothermal conditions and were structurally, chemically, and spectroscopically characterized. 1 crystallizes in space group Pbca, a=7.085(2) Å, b=11.986(3) Å, c=13.913(4) Å, V=1181.5(5) Å 3, Z=8; 2 is in P2(1)/ c, a=5.742(1) Å, b=7.789(2) Å, c=7.928(2) Å, V=90.703(2) Å 3, and Z=2. These are the first structures reported for uranyl compounds containing tellurate. The U 6+ cations are present as (UO 2) 2+ uranyl ions that are coordinated by O atoms to give pentagonal and square bipyramids in compounds 1 and 2, respectively. The structural unit in 1 is a sheet consisting of chains of edge-sharing uranyl pentagonal bipyramids that are one bipyramid wide, linked through the dimers of TeO 6 octahedra. In 2, uranyl square bipyramids share each of their equatorial vertices with different TeO 6 octahedra, giving a sheet with the autunite-type topology. Sheets in 1 and 2 are connected through the low-valence cations that are located in the interlayer region. The structures of 1 and 2 are compared to those of uranyl compounds containing octahedrally coordinated cations.

Ling, Jie; Ward, Matthew; Burns, Peter C.

2011-02-01

219

On the role of transforming growth factor-? in the growth inhibitory effects of retinoic acid in human pancreatic cancer cells  

PubMed Central

Background Retinoids are potent growth inhibitory and differentiating agents in a variety of cancer cell types. We have shown that retinoids induce growth arrest in all pancreatic cancer cell lines studied, regardless of their p53 and differentiation status. However, the mechanism of growth inhibition is not known. Since TGF-?2 is markedly induced by retinoids in other cancers and mediates MUC4 expression in pancreatic cancer cells, we investigated the role of TGF-? in retinoic acid-mediated growth inhibition in pancreatic cancer cells. Results Retinoic acid markedly inhibited proliferation of two cell lines (Capan-2 and Hs766T) in a concentration and time-dependent manner. Retinoic acid increased TGF-?2 mRNA content and secretion of the active and latent forms of TGF-?2 (measured by ELISA and bioassay). The concentrations of active and TGF-?2 secreted in response to 0.1 – 10 ?M retinoic acid were between 1–5 pM. TGF-?2 concentrations within this range also inhibited proliferation. A TGF-? neutralizing antibody blocked the growth inhibitory effects of retinoic acid in Capan-2 cells and partially inhibitory the effects in Hs766T cells. Conclusion These findings indicate that TGF-? can cause growth inhibition of pancreatic cancer cells, in a p53-independent manner. Furthermore, it demonstrates the fundamental role of TGF-? in growth inhibition in response to retinoic acid treatment is preserved in vitro.

Singh, Brahmchetna; Murphy, Richard F; Ding, Xian-Zhong; Roginsky, Alexandra B; Bell, Richard H; Adrian, Thomas E

2007-01-01

220

Inhibitory effect of the Agrobacterium rhizogenes rolC gene on rabdosiin and rosmarinic acid production in Eritrichium sericeum and Lithospermum erythrorhizon transformed cell cultures.  

PubMed

Rabdosiin and related caffeic acid metabolites have been proposed as active pharmacological agents demonstrating potent anti-HIV and antiallergic activities. We transformed Eritrichium sericeum and Lithospermum erythrorhizon seedlings by the rolC gene, which has been recently described as an activator of plant secondary metabolism. Surprisingly, the rolC-transformed cell cultures of both plants yielded two- to threefold less levels of rabdosiin and rosmarinic acid (RA) than respective control cultures. This result establishes an interesting precedent when the secondary metabolites are differently regulated by a single gene. We show that the rolC gene affects production of rabdosiin and RA irrespective of the methyl jasmonate (MeJA)-mediated and the Ca(2+)-dependent NADPH oxidase pathways. Cantharidin, an inhibitor of serine/threonine phosphatases, partly diminishes the rolC-gene inhibitory effect that indicates involvement of the rolC-gene-mediated signal in plant regulatory controls, mediated by protein phosphatases. We also show that the control MeJA-stimulated E. sericeum root culture produces (-)-rabdosiin up to 3.41% dry weight, representing the highest level of this substance for plant cell cultures reported so far. PMID:15688226

Bulgakov, Victor P; Veselova, M V; Tchernoded, G K; Kiselev, K V; Fedoreyev, S A; Zhuravlev, Yu N

2005-06-01

221

A Simple and Efficient Synthesis of an Acid-labile Polyphosphoramidate by Organobase-catalyzed Ring-Opening Polymerization and Transformation to Polyphosphoester Ionomers by Acid Treatment  

PubMed Central

The direct synthesis of an acid-labile polyphosphoramidate by organobase-catalyzed ring-opening polymerization and an overall two-step preparation of polyphosphodiester ionomers (PPEI) by acid-assisted cleavage of the phosphoramidate bonds along the backbone of the polyphosphoramidate were developed in this study. The ultrafast organobase-catalyzed ring-opening polymerization of a cyclic phospholane methoxyethyl amidate monomer initiated by benzyl alcohol allowed for the preparation of well-defined polyphosphoramidates (PPA) with predictable molecular weights, narrow molecular weight distributions (PDI<1.10), and well-defined chain ends. Cleavage of the acid-labile phosphoramidate bonds on the polyphosphoramidate repeat units was evaluated under acidic conditions over a pH range of 1–5, and the complete hydrolysis produced polyphosphodiesters. The thermal properties of the resulting polyphosphoester ionomer acid and polyphosphoester ionomer sodium salt exhibited significant thermal stability. The parent PPA and both forms of the PPEIs showed low cytotoxicities toward HeLa cells and RAW 264.7 mouse macrophage cells. The synthetic methodology developed here has enriched the family of water-soluble polymers prepared by rapid and convenient organobase-catalyzed ring-opening polymerizations and straightforward chemical medication reactions, which are designed to be hydrolytically degradable and have promise for numerous biomedical and other applications.

Zhang, Shiyi; Wang, Hai; Shen, Yuefei; Zhang, Fuwu; Seetho, Kellie; Zou, Jiong; Taylor, John-Stephen A.; Dove, Andrew P.; Wooley, Karen L.

2013-01-01

222

Hydroxyl radical production and storage in analogues of amorphous interstellar silicates: a possible "wet" accretion phase for inner telluric planets  

NASA Astrophysics Data System (ADS)

Context. Interstellar silicate grains are thought to be amorphized by interaction with high- and low-energy particle interactions in astrophysical environments. In addition, low energy (a few keV) particles will implant atoms within the grains. Aims: In this paper we experimentally investigate the consequence of the implantation of H+ at low irradiation energies into analogues of interstellar silicate grains, and look for the formation of hydroxyl radicals within the silicate matrix. Methods: Thin amorphous silicate films (~100 nm) were sequentially irradiated with H+ ions at low energies (3.5, 2.5 and then 1.5 keV) ensuring an implantation of the ions through the full depth of the films. The fluences used, 3 × 1016, 1017 and 3 × 1017 H+/cm2, are compatible with those expected in shocks in the interstellar medium. We used infrared spectroscopy to monitor and quantify the OH band evolution after irradiation. In order to distinguish the newly formed OH groups from those originating from unavoidable atmospheric contamination, the D/H depth ratios were measured with a NanoSIMS ion microprobe. Results: An increase in the OH band strength in the infrared spectra after irradiation reveals the formation of OH bonds within the irradiated silicate thin films. NanoSIMS measurements of the D/H signature in the region of ion implantation show that the newly-formed OH groups make up about 40% of the observed OH band in the IR, the rest are due to an atmospheric hydroxylation of the sample. Only about 2% of the incident ions lead to OH bond formation and, at most, the irradiated silicates retain about 3% of the incident protons as OH groups within their structure. Conclusions: Our laboratory experimental simulations show a possible production and storage of hydroxyl radicals in amorphous laboratory silicates. In the astrophysical context, such OH radicals, strongly bonded to pre-accretion material, could constitute a non negligible reservoir of -OH, thus water. These experimental results allow us to revisit and reinstate the hypothesis of a possible "wet" accretion of the telluric planets early in the history of the formation of the Solar System.

Djouadi, Z.; Robert, F.; Le Sergeant D'Hendecourt, L.; Mostefaoui, S.; Leroux, H.; Jones, A. P.; Borg, J.

2011-07-01

223

Synthesis and transformations of di-endo-3-aminobicyclo-[2.2.2]oct-5-ene-2-carboxylic acid derivatives.  

PubMed

all-endo-3-amino-5-hydroxybicyclo[2.2.2]octane-2-carboxylic acid (13) and all-endo-5-amino-6-(hydroxymethyl)bicyclo[2.2.2]octan-2-ol (10) were prepared via dihydro-1,3-oxazine or g-lactone intermediates by the stereoselective functionalization of an N-protected derivative of endo-3-aminobicyclo[2.2.2]oct-5-ene-2-carboxylic acid (2). Ring closure of b-amino ester 4 resulted in tricyclic pyrimidinones 15 and 16. The structures, stereochemistry and relative configurations of the synthesized compounds were determined by IR and NMR. PMID:21900870

Palkó, Márta; Sohár, Pál; Fülöp, Ferenc

2011-01-01

224

Stability of fatty acid monolayers and the relationship between equilibrium spreading pressure, phase transformations, and polymorphic crystal forms  

Microsoft Academic Search

Force-area isotherms were obtained for hexa- decanoic, octadecanoic, eicosanoic, and docosanoic acid mono- layers at different compression rates. Equilibrium spreading pressures were determined both by monolayer collapse and by spreading from the bulk phase. Monolayers formed metastable phases at all pressures above their equilibrium spreading pressures and at all surface areas smaller than the surface areas at their equilibrium spreading

RICHARD E. HEIKKILA; CHUI N. KWONG; DAVID G. CORNWELL

225

CHEMISTRY OF FOG WATER IN CALIFORNIA'S CENTRAL VALLEY: 2. PHOTOCHEMICAL TRANSFORMATIONS OF AMINO ACIDS AND ALKYL AMINES. (R825433)  

EPA Science Inventory

Although amino compounds are seemingly ubiquitous in atmospheric particles and deposition, little is known of their fate in the troposphere. We report here on the fate of 21 amino acids and alkyl amines in fog waters from Davis, California, illuminated with simulated sunlight ...

226

A Fourier transform infrared spectroscopic study of Mg-rich, Mg-poor and acid leached palygorskites.  

PubMed

The FTIR spectra of pure magnesium-rich (Mg-rich) and magnesium-poor (Mg-poor) palygorskites, before and after short-term (<7 h) and long-term (360 h) acid leaching are presented here. Comparison of decomposition spectra of Mg-rich and Mg-poor palygorskites clearly shows that the absorption peaks related to pairs of octahedral cation differ depending on the octahedral site occupancy. Short-term acid leaching of palygorskites results in significant changes to FTIR absorption bands near 1200 and 790 cm-1. As the acid attack progresses, the band at 1200 cm-1 shifts to lower wavenumbers, whilst the band at 790 cm-1, which here is assigned to SiU-O-SiD symmetrical stretching vibration, shifts to higher wavelengths. Longer-term leaching of palygorskites results in the disappearance of 900-1200 cm-1 absorption bands, showing that the palygorskite has largely decomposed to amorphous silica. Assignments of several other bands have been made as follows: several vibrations relate to OH, i.e. 847 cm-1, hygroscopic water (1635 cm-1), Si-O vibrations 1100, 611-621, 470-481 cm-1, etc. appear in the FTIR spectra of 360 h acid leached palygorskite. Three bands near 1100, 611-621 and 470-481 cm-1 relate to Si-O vibration of an ideal hexagonal (Si2O5)n sheet. PMID:16824788

Cai, Yuanfeng; Xue, Jiyue; Polya, D A

2007-02-01

227

A Fourier transform infrared spectroscopic study of Mg-rich, Mg-poor and acid leached palygorskites  

NASA Astrophysics Data System (ADS)

The FTIR spectra of pure magnesium-rich (Mg-rich) and magnesium-poor (Mg-poor) palygorskites, before and after short-term (<7 h) and long-term (360 h) acid leaching are presented here. Comparison of decomposition spectra of Mg-rich and Mg-poor palygorskites clearly shows that the absorption peaks related to pairs of octahedral cation differ depending on the octahedral site occupancy. Short-term acid leaching of palygorskites results in significant changes to FTIR absorption bands near 1200 and 790 cm -1. As the acid attack progresses, the band at 1200 cm -1 shifts to lower wavenumbers, whilst the band at 790 cm -1, which here is assigned to Si U-O-Si D symmetrical stretching vibration, shifts to higher wavelengths. Longer-term leaching of palygorskites results in the disappearance of 900-1200 cm -1 absorption bands, showing that the palygorskite has largely decomposed to amorphous silica. Assignments of several other bands have been made as follows: several vibrations relate to OH, i.e. 847 cm -1, hygroscopic water (1635 cm -1), Si-O vibrations 1100, 611-621, 470-481 cm -1, etc. appear in the FTIR spectra of 360 h acid leached palygorskite. Three bands near 1100, 611-621 and 470-481 cm -1 relate to Si-O vibration of an ideal hexagonal (Si 2O 5) n sheet.

Cai, Yuanfeng; Xue, Jiyue; Polya, D. A.

2007-02-01

228

In vivo human skin permeability enhancement by oleic acid: transepidermal water loss and fourier-transform infrared spectroscopy studies  

Microsoft Academic Search

The skin barrier function can be evaluated by measuring the rate of transepidermal water loss (TEWL). This technique can also be used to elucidate the effect of enhancers on the skin barrier. In this in vivo study the effect of oleic acid in propylene glycol (OA\\/PG) has been investigated on 10 human volunteers of both sexes (age: 20–40 years). A

Hanafi Tanojo; Hans E Junginger; Harry E Boddé

1997-01-01

229

Rapid transformations of plant water-soluble organic compounds in relation to cation mobilization in an acid Oxisol  

Microsoft Academic Search

The maintenance of plant residues on the surface of acid soils in no-tillage cropping systems reportedly increases the downward mobility of Ca and Al. This study investigated the effects of application of aqueous extracts of residues of radish (Raphanus sativus), blue lupine (Lupinus angustifolius), black oat (Avena strigosa), soybean (Glicine max), and wheat (Triticum aestivum), without incubation (initial extract) or

J. C. Franchini; F. J. Gonzalez-Vila; F. Cabrera; M. Miyazawa; M. A. Pavan

2001-01-01

230

AN ANALYSIS OF CELLULAR AND SUBCELLULAR SYSTEMS WHICH TRANSFORM THE SPECIES CHARACTER OF ACID PHOSPHATASE IN ACETABULARIA  

Microsoft Academic Search

Several species-specific molecular forms of acid phosphatase arc known to exist in the uni- cellular green alga Acetabularia. In graft combinations between cells of Acetabularia medi- terranea (reed) and Acicularia Schenckii (acic) the expression of the reed phosphatase is dominant over acic phosphatasc. There is good evidence that in such grafts the preexisting acic phos- phatase is converted on the

KONRAD KECK; ELIZABETH A. CHOULES

1963-01-01

231

Fourier Transform Infrared Spectroscopy and Multivariate Analysis for Online Monitoring of Dibutyl Phosphate Degradation Product in Tributyl Phosphate /n-Dodecane/Nitric Acid Solvent  

SciTech Connect

In liquid-liquid extraction separation processes, accumulation of organic solvent degradation products is detrimental to the process robustness and frequent solvent analysis is warranted. Our research explores feasibility of online monitoring of the organic solvents relevant to used nuclear fuel reprocessing. This paper describes the first phase of developing a system for monitoring the tributyl phosphate (TBP)/n-dodecane solvent commonly used to separate used nuclear fuel. In this investigation, the effect of extraction of nitric acid from aqueous solutions of variable concentrations on the quantification of TBP and its major degradation product dibutyl phosphoric acid (HDBP) was assessed. Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy was used to discriminate between HDBP and TBP in the nitric acid-containing TBP/n-dodecane solvent. Multivariate analysis of the spectral data facilitated the development of regression models for HDBP and TBP quantification in real time, enabling online implementation of the monitoring system. The predictive regression models were validated using TBP/n-dodecane solvent samples subjected to the high dose external gamma irradiation. The predictive models were translated to flow conditions using a hollow fiber FTIR probe installed in a centrifugal contactor extraction apparatus demonstrating the applicability of the FTIR technique coupled with multivariate analysis for the online monitoring of the organic solvent degradation products.

Levitskaia, Tatiana G.; Peterson, James M.; Campbell, Emily L.; Casella, Amanda J.; Peterman, Dean; Bryan, Samuel A.

2013-11-05

232

Identification of black carbon derived structures in a volcanic ash soil humic acid by Fourier transform ion cyclotron resonance mass spectrometry.  

PubMed

Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), coupled with cross-polarization magic angle spinning 13C nuclear magnetic resonance (NMR) spectroscopy and Kendrick mass defect analysis, was used to study the molecular composition of an aromatic carbon-rich humic acid extracted from a dark black soil from Iwata, Japan. Black carbon, produced by the incomplete combustion of fossil fuels and organic matter, has been suggested as a major component of humic acids having intense peaks in the aromatic and carboxyl regions of the 13C NMR spectrum. Taking advantage of the high resolving power of FT-ICR MS to make precise formula assignments, three different types of highly carboxylated polycyclic aromatic compounds were identified in the sample: linearly fused aromatic structures, aromatic structures linked by carbon-carbon single bonds, and highly condensed aromatic structures. These carboxylated aromatic structures have a low mass defect in their mass spectra due to their abundance of oxygen and deficiency of hydrogen. This mass defect is observed in the vast majority of peaks present in the entire mass spectrum, differentiating them from structures that are hydrogen-rich (e.g., fatty acids, proteins, carbohydrates). Thus, we conclude that the bulk of the sample analyzed is comprised of these heavily carboxylated, hydrogen-deficient, condensed aromatic structures, features believed to be characteristic of black carbon-like material. PMID:15260339

Kramer, Robert W; Kujawinski, Elizabeth B; Hatcher, Patrick G

2004-06-15

233

Two-Dimensional Fourier Transform Infrared (FT-IR) Correlation Spectroscopy Study of the Imidization Reaction from Polyamic Acid to Polyimide.  

PubMed

The mechanism of the thermal imidization of solid-state polyamic acid was studied using Fourier transform infrared (FT-IR) spectroscopy using the two-dimensional correlation spectroscopy method. It is assumed that two isomers exist in a polyamic acid segment: one is called the para-segment, which favors imidization reaction, the other is the meta-segment, which is not in favor for imidization unless the temperature is high enough. The results show that the imidization process differs for the two states of polyamic acid segments. The para-segment is more sensitive to the heat environment for the formation of imide ring, and it will take several intermediate steps to complete the ring closure at the aid of the solvent. As for the meta-segment, the ring will be closed before the imide formation due to the powerful energy provided in the high-temperature environment, and the ever-increasing chain rigidity and the loss of solvent during the heating process make this path the only option to continue the imidization process. PMID:25014721

Xu, Yuan; Zhang, Qinghua

2014-06-01

234

Fourier Transform Infrared Spectroscopy and Multivariate Analysis for Online Monitoring of Dibutyl Phosphate Degradation Product in Tributyl Phosphate/n-Dodecane/Nitric Acid Solvent  

SciTech Connect

In liquid–liquid extraction separation processes, accumulation of organic solvent degradation products is detrimental to the process robustness, and frequent solvent analysis is warranted. Our research explores the feasibility of online monitoring of the organic solvents relevant to used nuclear fuel reprocessing. This paper describes the first phase of developing a system for monitoring the tributyl phosphate (TBP)/n-dodecane solvent commonly used to separate used nuclear fuel. In this investigation, the effect of extraction of nitric acid from aqueous solutions of variable concentrations on the quantification of TBP and its major degradation product dibutylphosphoric acid (HDBP) was assessed. Fourier transform infrared (FTIR) spectroscopy was used to discriminate between HDBP and TBP in the nitric acid-containing TBP/n-dodecane solvent. Multivariate analysis of the spectral data facilitated the development of regression models for HDBP and TBP quantification in real time, enabling online implementation of the monitoring system. The predictive regression models were validated using TBP/n-dodecane solvent samples subjected to high-dose external ?-irradiation. The predictive models were translated to flow conditions using a hollow fiber FTIR probe installed in a centrifugal contactor extraction apparatus, demonstrating the applicability of the FTIR technique coupled with multivariate analysis for the online monitoring of the organic solvent degradation products.

Tatiana G. Levitskaia; James M. Peterson; Emily L. Campbell; Amanda J. Casella; Dean R. Peterman; Samuel A. Bryan

2013-12-01

235

Interleukin-8 (IL-8) over-production and autocrine cell activation are key factors in monomethylarsonous acid [MMA(III)]-induced malignant transformation of urothelial cells  

SciTech Connect

The association between chronic human exposure to arsenicals and bladder cancer development is well recognized; however, the underlying molecular mechanisms have not been fully determined. We propose that inflammatory responses can play a pathogenic role in arsenic-related bladder carcinogenesis. In previous studies, it was demonstrated that chronic exposure to 50 nM monomethylarsenous acid [MMA(III)] leads to malignant transformation of an immortalized model of urothelial cells (UROtsa), with only 3 mo of exposure necessary to trigger the transformation-related changes. In the three-month window of exposure, the cells over-expressed pro-inflammatory cytokines (IL-1?, IL-6 and IL-8), consistent with the sustained activation of NFK? and AP1/c-jun, ERK2, and STAT3. IL-8 was over-expressed within hours after exposure to MMA(III), and sustained over-expression was observed during chronic exposure. In this study, we profiled IL-8 expression in UROtsa cells exposed to 50 nM MMA(III) for 1 to 5 mo. IL-8 expression was increased mainly in cells after 3 mo MMA(III) exposure, and its production was also found increased in tumors derived from these cells after heterotransplantation in SCID mice. UROtsa cells do express both receptors, CXCR1 and CXCR2, suggesting that autocrine cell activation could be important in cell transformation. Supporting this observation and consistent with IL-8 over-expression, CXCR1 internalization was significantly increased after three months of exposure to MMA(III). The expression of MMP-9, cyclin D1, bcl-2, and VGEF was significantly increased in cells exposed to MMA(III) for 3 mo, but these mitogen-activated kinases were significantly decreased after IL-8 gene silencing, together with a decrease in cell proliferation rate and in anchorage-independent colony formation. These results suggest a relevant role of IL-8 in MMA(III)-induced UROtsa cell transformation. -- Highlights: ? IL-8 is over-expressed in human MMA(III)-exposed urothelial cells. ? Internal CXCR1 and tumor progression markers are also increased. ? IL-8 silencing decreased malignant transformation markers in MMA(III)-exposed cells.

Escudero-Lourdes, C., E-mail: cescuder@uaslp.mx [Centro de Investigación y Estudios de Posgrado (CIEP), Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí (Mexico); Wu, T.; Camarillo, J.M.; Gandolfi, A.J. [Department of Pharmacology and Toxicology College of Pharmacy, University of Arizona. Tucson, AZ (United States)] [Department of Pharmacology and Toxicology College of Pharmacy, University of Arizona. Tucson, AZ (United States)

2012-01-01

236

Singular transformations of arenesulfonic acids N -(1Aryl2,2-dichloroethyl)amides under the action of secondary amines  

Microsoft Academic Search

In the course of reactivity investigation of typical members of the series of amidodichloroethyl-substituted arenes Ia–Ic whose synthesis we had previously developed starting from dichloroacetic aldehyde imines [1, 2] we discovered their singular reactions in highly polar aprotic solvents in the presence of secondary amines and inorganic bases which led to the formation of 4-chlorobenzenesulfonic acid N-(2-oxo-2-arylethyl)amides in fair yields.

I. B. Rozentsweig; A. V. Popov; A. V. Brikov; A. N. Mirskova; G. G. Levkovskaya

2007-01-01

237

An application of derivative and continuous wavelet transforms to the overlapping ratio spectra for the quantitative multiresolution of a ternary mixture of paracetamol, acetylsalicylic acid and caffeine in tablets  

Microsoft Academic Search

Quantitative multiresolution of tablets and ternary mixtures of paracetamol (PAR), acetylsalicylic acid (ASP) and caffeine (CAF) having strongly overlapping spectra was accomplished by two graphical transform methods as ratio spectra first derivative-zero crossing and ratio spectra-continuous wavelet transform-zero crossing (ratio spectra CWT-zero crossing) methods. In this study, ratio spectra derivative-zero crossing and ratio spectra CWT-zero crossing methods are based on

Erdal Dinç; Abdil Özdemir; Dumitru Baleanu

2005-01-01

238

Nondestructive quantification of the soluble-solids content and the available acidity of apples by Fourier-transform near-infrared spectroscopy  

SciTech Connect

This research evaluated the feasibility of using Fourier-transform near-infrared (FT-NIR) spectroscopy to quantify the soluble-solids content (SSC) and the available acidity (VA) in intact apples. Partial least-squares calibration models, obtained from several preprocessing techniques (smoothing, derivative, etc.) in several wave-number ranges were compared. The best models were obtained with the high coefficient determination (r{sup 2}) 0.940 for the SSC and a moderate r{sup 2} of 0.801 for the VA, root-mean-square errors of prediction of 0.272% and 0.053%, and root-mean-square errors of calibration of 0.261% and 0.046%, respectively. The results indicate that the FT-NIR spectroscopy yields good predictions of the SSC and also showed the feasibility of using it to predict the VA of apples.

Ying Yibin; Liu Yande; Tao Yang

2005-09-01

239

Using radiative transfer models to study the atmospheric water vapor content and to eliminate telluric lines from high-resolution optical spectra  

NASA Astrophysics Data System (ADS)

The Radiative Transfer Model (RTM) and the retrieval algorithm, incorporated in the SCIATRAN 2.2 software package developed at the Institute of Remote Sensing/Institute of Enviromental Physics of Bremen University (Germany), allows to simulate, among other things, radiance/irradiance spectra in the 2400--24 000 Å range. In this work we present applications of RTM to two case studies. In the first case the RTM was used to simulate direct solar irradiance spectra, with different water vapor amounts, for the study of the water vapor content in the atmosphere above Sierra Nevada Observatory. Simulated spectra were compared with those measured with a spectrometer operating in the 8000--10 000 Å range. In the second case the RTM was used to generate telluric model spectra to subtract the atmospheric contribution and correct high-resolution stellar spectra from atmospheric water vapor and oxygen lines. The results of both studies are discussed.

Gardini, A.; Maíz Apellániz, J.; Pérez, E.; Quesada, J. A.; Funke, B.

2013-05-01

240

Expression and Functional Characterization of the Agrobacterium VirB2 Amino Acid Substitution Variants in T-pilus Biogenesis, Virulence, and Transient Transformation Efficiency  

PubMed Central

Agrobacterium tumefaciens is a phytopathogenic bacterium that causes crown gall disease by transferring transferred DNA (T-DNA) into the plant genome. The translocation process is mediated by the type IV secretion system (T4SS) consisting of the VirD4 coupling protein and 11 VirB proteins (VirB1 to VirB11). All VirB proteins are required for the production of T-pilus, which consists of processed VirB2 (T-pilin) and VirB5 as major and minor subunits, respectively. VirB2 is an essential component of T4SS, but the roles of VirB2 and the assembled T-pilus in Agrobacterium virulence and the T-DNA transfer process remain unknown. Here, we generated 34 VirB2 amino acid substitution variants to study the functions of VirB2 involved in VirB2 stability, extracellular VirB2/T-pilus production and virulence of A. tumefaciens. From the capacity for extracellular VirB2 production (ExB2+ or ExB2?) and tumorigenesis on tomato stems (Vir+ or Vir?), the mutants could be classified into three groups: ExB2?/Vir?, ExB2?/Vir+, and ExB2+/Vir+. We also confirmed by electron microscopy that five ExB2?/Vir+ mutants exhibited a wild-type level of virulence with their deficiency in T-pilus formation. Interestingly, although the five T-pilus?/Vir+ uncoupling mutants retained a wild-type level of tumorigenesis efficiency on tomato stems and/or potato tuber discs, their transient transformation efficiency in Arabidopsis seedlings was highly attenuated. In conclusion, we have provided evidence for a role of T-pilus in Agrobacterium transformation process and have identified the domains and amino acid residues critical for VirB2 stability, T-pilus biogenesis, tumorigenesis, and transient transformation efficiency.

Wu, Hung-Yi; Chen, Chao-Ying; Lai, Erh-Min

2014-01-01

241

Regulation of adenovirus and cellular gene expression and of cellular transformation by the E1B-encoded 175-amino-acid protein.  

PubMed Central

Mutants of type 5 adenovirus that fail to express the E1B-gene-encoded 175-amino-acid (175R) protein are unable to morphologically transform primary or continuous cultures of rat embryo fibroblast cells. This phenotype could result from a direct effect of this E1B polypeptide (along with E1A polypeptides) on cellular gene expression resulting in a pathway leading to altered cell growth or from an indirect role of the 175R protein made possible by its ability to modulate viral early-gene (most likely E1A) expression. To distinguish between these two models, viruses were constructed that expressed the individual E1A 13S and 12S genes in the presence of either the E1B 175R or 495R protein. Regardless of the E1A gene product that was expressed, viruses that failed to express the E1B 175R protein were transformation defective. Additional studies suggest that the E1A 289R protein and E1B 495R protein function in a common pathway leading to the establishment of the transformed cell. We also observe that E3 gene expression by viruses that fail to express the E1A 289R protein affects the efficiency of focus formation. When tested in both nonpermissive CREF cells and permissive HeLa cells, the lack of 175R protein expression appeared to have no effect (a transient twofold decrease in E1A mRNA accumulation was observed in CREF cells) on viral early-gene expression. These results suggest that the initiation of the transformed cell phenotype occurs because of some interaction in a common pathway between the viral E1A proteins and E1B 175R protein. Furthermore, we have shown that the E1B 175R protein does not enhance the rate of transcription initiation from the mouse immunoglobulin heavy chain gene promoter when these sequences are localized on a viral genome, and it does not diminish the ability of the E1A proteins to decrease the rate of enhancer-dependent transcription. Images

Herbst, R S; Hermo, H; Fisher, P B; Babiss, L E

1988-01-01

242

Monomethylarsonous acid produces irreversible events resulting in malignant transformation of a human bladder cell line following 12 weeks of low-level exposure.  

PubMed

Arsenic is a known human bladder carcinogen; however, the mechanisms underlying arsenical-induced bladder carcinogenesis are not understood. Previous research has demonstrated that exposure of a nontumorigenic human urothelial cell line, UROtsa, to 50 nM monomethylarsonous acid (MMA(III)) for 52 weeks resulted in malignant transformation. To focus research on the early mechanistic events leading to MMA(III)-induced malignancy, the goal of this research was to resolve the critical period in which continuous MMA(III) exposure (50 nM) induces the irreversible malignant transformation of UROtsa cells. An increased growth rate of UROtsa cells results after 12 weeks of MMA(III) exposure. Anchorage-independent growth occurred after 12 weeks with a continued increase in colony formation when 12-week exposed cells were cultured for an additional 12 or 24 weeks without MMA(III) exposure. UROtsa cells as early as 12 weeks MMA(III) exposure were tumorigenic in severe combined immunodeficiency mice with tumorigenicity increasing when 12-week exposed cells were cultured for an additional 12 or 24 weeks in the absence of MMA(III) exposure. To assess potential underlying mechanisms associated with the early changes that occur during MMA(III)-induced malignancy, DNA methylation was assessed in known target gene promoter regions. Although DNA methylation remains relatively unchanged after 12 weeks of exposure, aberrant DNA methylation begins to emerge after an additional 12 weeks in culture and continues to increase through 24 weeks in culture without MMA(III) exposure, coincident with the progression of a tumorigenic phenotype. Overall, these data demonstrate that 50 nM MMA(III) is capable of causing irreversible malignant transformation in UROtsa cells after 12 weeks of exposure. Having resolved an earlier timeline in which MMA(III)-induced malignant transformation occurs in UROtsa cells will allow for mechanistic studies focused on the critical biological changes taking place within these cells prior to 12 weeks of exposure, providing further evidence about potential mechanisms of MMA(III)-induced carcinogenesis. PMID:20375083

Wnek, Shawn M; Jensen, Taylor J; Severson, Paul L; Futscher, Bernard W; Gandolfi, A Jay

2010-07-01

243

Stability of monomeric Cro variants: Isoenergetic transformation of a type I? to a type II? ?-hairpin by single amino acid replacements  

PubMed Central

The thermodynamic stabilities of three monomeric variants of the bacteriophage ? Cro repressor that differ only in the sequence of two amino acids at the apex of an engineered ?-hairpin have been determined. The sequences of the turns are EVK-XX-EVK, where the two central residues are DG, GG, and GT, respectively. Standard-state unfolding free energies, determined from circular dichroism measurements as a function of urea concentration, range from 2.4 to 2.7 kcal/mole, while those determined from guanidine hydrochloride range from 2.8 to 3.3 kcal/mole for the three proteins. Thermal denaturation yields van’t Hoff unfolding enthalpies of 36 to 40 kcal /mole at midpoint temperatures in the range of 53 to 58°C. Extrapolation of the thermal denaturation free energies with heat capacities of 400 to 600 cal/mole deg gives good agreement with the parameters determined in denaturant titrations. As predicted from statistical surveys of amino acid replacements in ?-hairpins, energetic barriers to transformation from a type I? turn (DG) to a type II? turn (GT) can be quite small.

Mollah, A.K.M.M.; Stennis, Rhonda L.; Mossing, Michael C.

2003-01-01

244

Bovine ?1-acid glycoprotein, a thermostable version of its human counterpart: Insights from Fourier transform infrared spectroscopy and in silico modelling.  

PubMed

?1-Acid glycoprotein (AGP) is a plasma protein and a member of the acute phase response. AGP is known to bind and carry several biologically active compounds, as well as to down-modulate the immune system activities. In this work, the structure of bovine AGP has been investigated by Fourier-Transform infrared spectroscopy. A model structure has been obtained on the basis of human AGP and refined by molecular dynamics. In spite of the similar structure, bovine AGP shows an unexpectedly higher (?20 °C) thermostability than its human counterpart. Inspection of the model structure has pointed out the presence of 12 ionic bridges and 2 sulphur-aromatic interactions, whereas only 6 ionic bridges were detected in human AGP. The high number (9) of glutamic acid residues involved in the ionic interactions might explain the significantly decreased thermostability measured at pH 5.5 (Tm ? 71 °C) with respect to pH 7.4 (Tm ? 81 °C), whereas thermostability of human AGP was only slightly affected by lowering the pH. As in human AGP and several other lipocalins, a temperature-induced molten globule state has been observed in the denaturation pathway of bovine AGP. PMID:24530968

Baldassarre, Maurizio; Galeazzi, Roberta; Maggiore, Beatrice; Tanfani, Fabio; Scirè, Andrea

2014-07-01

245

Transformation of 2,4,6-trimethylphenol and furfuryl alcohol, photosensitised by Aldrich humic acids subject to different filtration procedures.  

PubMed

Suspended particles in a system made up of Aldrich humic acids (HAs) in water account for about 13% of the total HA mass, 10-11% of the organic carbon and 9-11% of radiation extinction in the UVA region. Extinction would be made up of radiation scattering (less than one third) and absorption (over two thirds). The contribution of particles to the degradation rates of trimethylphenol and furfuryl alcohol (FFA) (probes of triplet states and (1)O(2), respectively) was lower than 10% and possibly negligible. The results indicate that triplet states and (1)O(2) occurring in the solution bulk are mostly produced by the dissolved HA fraction. Experimental data would not exclude production of (1)O(2) in particle hydrophobic cores, unavailable for reaction with FFA. However, the limited to negligible particle fluorescence places an upper limit to particle core photoactivity. PMID:22921648

Minella, Marco; Merlo, Maria Paola; Maurino, Valter; Minero, Claudio; Vione, Davide

2013-01-01

246

Unique relationship between interfacial tension test (IFT) and neutral number test (Acidity) of transformer insulation oil in PLN P3B JB - Jakarta and Banten Regional  

Microsoft Academic Search

Transformers are one of some important equipment on electricity network. Each utility, in this case PLN P3B Jawa-Bali, has to assure their reliability in order to maintain electrical power system stability by assessing transformer conditions. Insulation system, which consists of liquid and solid insulation, is the most important part of transformer system. The performance of transformer will depend on its

H. Gumilang

2009-01-01

247

Characterization of oil sands naphthenic acids treated with ultraviolet and microwave radiation by negative ion electrospray Fourier transform ion cyclotron resonance mass spectrometry.  

PubMed

Naphthenic acids (NAs) are concentrated in oil sand process water (OSPW) as a result of caustic oil sands extraction processes. There is considerable interest in methods for treatment of NAs in OSPW. Earlier work has shown that the combination of ultraviolet (UV) and microwave treatments in the laboratory was effective in reducing the concentration of classical NAs. Here we apply Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to further characterize NAs treated with (a) UV (254?nm) in the presence of TiO(2) catalyst; and/or (b) microwave irradiation (2.45?GHz). FT-ICR MS was used to characterize the NA fraction before and after treatment. Acidic oxygen-containing classes were most abundant in all samples whereas other heteroatomic classes were least abundant or not present in some samples. For example, the SO(2)-containing species were absent in UV- or combined UV- and microwave-treated samples. The O(2) class was dominant in all samples, indicative of NAs. However, samples treated with UV and microwave radiation have a lower relative abundance of other heteroatomic classes. We observed O(2), S(1)O(2), O(3), S(1)O(3), O(4), O(5), and O(6) classes, whereas the species with relatively high O(n) content, namely, the O(3), O(5), and O(6) classes, were present only in UV- and microwave-treated samples. The relatively high O(n) content is consistent with oxidation of the parent acids in treated samples. There may thus be potential implications for environmental forensics. For example, the monitoring of the ratio of SO(2):O(2) or tracking the relative abundances of O(2), O(3), O(4), O(5), and O(6) classes may provide insights for distinguishing naturally derived oil sands components from those that are process-related in aquatic environments. PMID:20941758

Headley, John V; Peru, Kerry M; Mishra, Sabyasachi; Meda, Venkatesh; Dalai, Ajay K; McMartin, Dena W; Mapolelo, Mmilili M; Rodgers, Ryan P; Marshall, Alan G

2010-11-15

248

Emissions of formaldehyde, acetic acid, methanol, and other trace gases from biomass fires in North Carolina measured by airborne Fourier transform infrared spectroscopy  

NASA Astrophysics Data System (ADS)

Biomass burning is an important source of many trace gases in the global troposphere. We have constructed an airborne trace gas measurement system consisting of a Fourier transform infrared spectrometer (FTIR) coupled to a "flow-through" multipass cell (AFTIR) and installed it on a U.S. Department of Agriculture Forest Service King Air B-90. The first measurements with the new system were conducted in North Carolina during April 1997 on large, isolated biomass fire plumes. Simultaneous measurements included Global Positioning System (GPS); airborne sonde; particle light scattering, CO, and CO2; and integrated filter and canister samples. AFTIR spectra acquired within a few kilometers of the fires yielded excess mixing ratios for 10 of the most common trace gases in the smoke: water, carbon dioxide, carbon monoxide, methane, formaldehyde, acetic acid, formic acid, methanol, ethylene, and ammonia. Emission ratios to carbon monoxide for formaldehyde, acetic acid, and methanol were each 2.5±1%. This is in excellent agreement with (and confirms the relevance of) our results from laboratory fires. However, these ratios are significantly higher than the emission ratios reported for these compounds in some previous studies of "fresh" smoke. We present a simple photochemical model calculation that suggests that oxygenated organic compounds should be included in the assessment of ozone formation in smoke plumes. Our measured emission factors indicate that biomass fires could account for a significant portion of the oxygenated organic compounds and HOx present in the tropical troposphere during the dry season. Our fire measurements, along with recent measurements of oxygenated biogenic emissions and oxygenated organic compounds in the free troposphere, indicate that these rarely measured compounds play a major, but poorly understood, role in the HOx, NOx, and O3 chemistry of the troposphere.

Yokelson, R. J.; Goode, J. G.; Ward, D. E.; Susott, R. A.; Babbitt, R. E.; Wade, D. D.; Bertschi, I.; Griffith, D. W. T.; Hao, W. M.

1999-12-01

249

Modulation of expression and cell surface binding of members of the transforming growth factor-beta superfamily during retinoic acid-induced osteoblastic differentiation of multipotential mesenchymal cells.  

PubMed

We have evaluated the effects of retinoic acid as a differentiating agent on two pluripotential mesenchymal stem cell lines, the mouse cell line C3H-10T1/2 (10T1/2), which has the capacity to differentiate in vitro into myoblasts, adipocytes, chondrocytes, and osteoblasts, and the rat cell line ROB-C26 (C26), which can, in culture, give rise to adipocytes, myoblasts, and osteoblasts. Retinoic acid (10(-6) M) reduces the incidence of myoblast and adipocyte formation and induces or increases alkaline phosphatase expression and responsiveness to PTH, two indicators of the osteoblastic phenotype. Because transforming growth factor-beta (TGF beta) superfamily members, including the different TGF beta isoforms and the bone morphogenetic proteins (BMPs), are thought to play a role in regulating bone and cartilage formation, and because exogenous TGF beta and BMP-2 have already been found to modulate osteoblastic differentiation of C26 and 10T1/2 cells, we evaluated the endogenous expression of these factors in both cell lines cultured in the presence or absence of retinoic acid. Our data show that C26 and 10T1/2 cells constitutively express a broad spectrum of TGF beta superfamily members. However, this pattern of expression is dramatically altered in response to retinoic acid. Specifically, expression of TGF beta 1 and especially TGF beta 2 is strongly increased, whereas TGF beta 3 expression is down-regulated. These changes are accompanied by a striking decline in TGF beta receptor expression levels at the cell surface. Furthermore, BMP-2 and -4 expression are decreased after treatment with retinoic acid, whereas vgr-1/BMP-6 expression is induced in C26 cells, but decreased in 10T1/2 cells. These results clearly show a dynamic changing pattern of TGF beta superfamily expression consequent to the induction of osteogenic differentiation and provide the first indication that TGF beta receptor down-regulation may be an essential part of this differentiation process. These data also establish the C26 and 10T1/2 cell lines as convenient in vitro model systems for exploring the autoregulation of osteogenic differentiation by members of the TGF beta superfamily. PMID:8385738

Gazit, D; Ebner, R; Kahn, A J; Derynck, R

1993-02-01

250

Herbicide Transformation  

PubMed Central

A strain of Fusarium solani isolated from soil by enrichment techniques used propanil (3?, 4?-dichloropropionanilide) as a sole source of organic carbon and energy for growth in pure culture. The primary product of the transformation of propanil by F. solani was isolated and identified as 3,4-dichloroaniline (DCA). This compound accumulated in the medium to a level (80 ?g/ml) which stopped further herbicide utilization. Herbicide utilization by F. solani was influenced by various environmental and nutritional factors. It was more sensitive to acid than alkaline pH. Added glucose and yeast extract increased the rate of propanil decomposition, and the reduced aeration retarded growth of the fungus and herbicide utilization. The growth of F. solani on propionate was inhibited by added DCA. Images

Lanzilotta, R. P.; Pramer, David

1970-01-01

251

Collection of VLE data for acid gas---alkanolamine systems using fourier transform infrared spectroscopy. [Vapor-liquid equilibrium  

SciTech Connect

The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. Inadequate data for vapor--liquid equilibrium (VLE) hinder the industry from converting operations to more energy efficient amine mixtures and conserving energy. Some energy reductions have been realized in the past decade by applying such amine systems as hindered'' amines, methyldiethanolamine (MDEA), and MDEA based amine mixtures. However, the lack of reliable and accurate fundamental VLE data impedes the commercial application of these more efficient alkanolamine systems. The first project objective is to improve the accuracy of vapor--liquid equilibrium measurements at low hydrogen sulfide concentrations. The second project objective is to measure the VLE for amine mixtures. By improving the accuracy of the VLE measurements on MDEA and mixtures with other amines, energy saving can be quickly and confidently implemented in the many existing absorption units already in use. If about 25% of the existing 95.3 billion SCFD gas purification capacity is converted to these new amine systems, the energy savings are estimated to be about 3 [times] 10[sup 14] BTU/yr.

Bullin, J.A.; Frazier, R.E.

1992-01-01

252

Effects of all-trans retinoic acid on signal pathway of cyclooxygenase-2 and Smad3 in transforming growth factor-?-stimulated glomerular mesangial cells.  

PubMed

All-trans retinoic acid (ATRA) has been used for the treatment of acute promyelocytic leukemia. It remains unclear, however, whether ATRA affects cyclooxygenase-2 (COX-2; an enzyme involved in prostaglandin production), PGE2, and thromboxane A2 (TXA2) (metabolic products of COX-2) by a transforming growth factor-?/Smad-signaling pathway, which plays important roles in mesangial-cell proliferation and renal fibrosis. In this study, the mRNA and protein of Smad3, Smad7, and COX-2 were detected by reverse transcription-polymerase chain reaction and Western blot, respectively, in mesangial cells stimulated by transforming growth factor-? (TGF-?) and treated with ATRA at various concentrations and times. The protein level of PGE2 and TXA2 was also measured by enzyme-linked immunosorbent assay. The localization of Smad3 and Smand7 was observed by confocal microscope. Cell proliferation was detected by MTT assay, while apoptosis was determined using Hoechest staining. The expression of Smad3, Smad7, and COX-2?mRNA and protein was increased by exogenous TGF-?, but inhibited by pretreatment of ATRA, in dose and time-dependent manners. In addition, the expression of Smad3 and Smad7 was significantly reduced not only by staurosporine, an inhibitor of threonine/serine protein kinases as well as smad, but also by NS-398, an inhibitor of COX-2. PGE2 and TXA2 were raised by TGF-?, but also decreased by ATRA, staurosporine, and NS-398. Moreover, ATRA reversed the translocation of Smad3 and Smad7 induced by TGF-?. Compared with the control, TGF-? also significantly enhanced proliferation and inhibited apoptosis of mesangial cells. ATRA dose-dependently inhibited TGF-?-induced cell proliferation, but had no significant effect on apoptosis in rat mesangial cells. Therefore, ATRA repressed COX-2, PGE2, and TXA2 via the TGF-?/Smad-signaling pathway and inhibited mesangial-cell proliferation, which might subsequently prevent renal fibrosis. PMID:24500985

Han, Jinyi; Zhang, Li; Chen, Xiaolan; Yang, Bin; Guo, Naifeng; Fan, Yaping

2014-03-01

253

Sources, transformation and fate of particulate amino acids and hexosamines under varying hydrological regimes in the tropical Wenchang/Wenjiao Rivers and Estuary, Hainan, China  

NASA Astrophysics Data System (ADS)

The small tropical Wenchang and Wenjiao Rivers on the island of Hainan, tropical China, are affected by effluents from municipal sewage, aquaculture and agriculture, and by contrasting hydrological regimes related to monsoon and tropical storms. In order to obtain information on the sources, transformation and fate of organic matter (OM) we investigated the amount and composition of amino acids and hexosamines as well as the carbon isotope composition in suspended particulate matter (SPM) from the Wenchang/Wenjiao Estuary. SPM was collected along the salinity gradient starting from the river sites, along the lagoon-shaped Bamen Bay to coastal waters during four sampling campaigns between 2006 and 2009. SPM concentrations ranged between 4.7 and 58.2 mg L-1. Apart from highest values after heavy rain events in spring and summer, SPM showed little seasonal variation, but increased with salinity. From SPM POC% (1.2-20.9%), C/N (4.9-16.5) and ?13Corg (-31.5 to -19.5‰), the molar composition and content of amino acids and hexosamines (8.2-156.2 mg g-1 dry weight) and by comparison with sediments, mangroves, soils and plants we are able to show that soil-derived material, freshwater and marine plankton were the major sources of suspended OM. High POC and amino acid contents were related to primary production sustained by dissolved nutrients to a large extent stemming from municipal and aquaculture effluents. Factor analysis showed that the suite of biogeochemical parameters measured clearly depict the terrestrial vs. marine origin and the freshness/reactivity of OM. The four groups of samples resulting from cluster analysis were basically related to varying hydrological regimes. With respect to the sources, degradation and fate of particulate OM the major factors were: (i) the year round input of labile, amino acid rich riverine OM matter at the freshwater dominated sites, (ii) high input of degraded soil OM after heavy rains with dispersal throughout the estuary and export to the adjacent coastal area, (iii) significant production of labile marine OM especially during summer inside the bay and the (iv) dominance of refractory marine OM during winter and spring season and in the offshore region. While a major part of the fresh OM fuelled by anthropogenic nutrients appears to be stored or recycled inside the bay, periodic torrential rainfalls can lead to a pulsed export of this OM to the coastal area where it may adversely affect seagrass meadows and coral reefs.

Unger, Daniela; Herbeck, Lucia S.; Li, Min; Bao, Hongyan; Wu, Ying; Zhang, Jing; Jennerjahn, Tim

2013-04-01

254

Collection of VLE data for acid gas - alkanolamine systems using Fourier transform infrared spectroscopy. Final report, September 29, 1990--September 30, 1996  

SciTech Connect

This report describes research from September 29, 1990 through September 30, 1996, involving the development a novel Fourier transform infrared (FTIR) spectroscopic apparatus and method for measuring vapor - liquid equilibrium (VLE) systems of carbon dioxide and hydrogen sulfide with aqueous alkanolamine solutions. The original apparatus was developed and modified as it was used to collect VLE data on acid gas systems. Vapor and liquid calibrations were performed for spectral measurements of hydrogen sulfide and carbon dioxide in the vapor and in solution with aqueous diethanolamine (DEA) and methyldiethanolamine (MDEA). VLE measurements were made of systems of hydrogen sulfide and carbon dioxide in 20 wt % DEA at 50{degrees}C and 40{degrees}C. VLE measurements were made of systems of hydrogen sulfide and carbon dioxide in 50 wt% and 23 wt% MDEA at 40{degrees}C and in 23 wt% MDEA at 50{degrees}C. VLE measurements were made of systems of hydrogen sulfide and carbon dioxide in 35 wt% MDEA + 5 wt% DEA and in 35 wt% MDEA + 10 wt% DEA at 40{degrees}C and 50{degrees}C. Measurements were made of residual amounts of carbon dioxide in each VLE system. The new FTIR spectrometer is now a consistently working and performing apparatus.

Bullin, J.A.; Rogers, W.J.

1996-11-01

255

Fluorescence excitation-emission matrix combined with regional integration analysis to characterize the composition and transformation of humic and fulvic acids from landfill at different stabilization stages.  

PubMed

Fluorescence excitation-emission matrix spectroscopy (EEMs) combined with fluorescence regional integration (FRI) analysis was used to investigate the composition and transformation of humic acid (HA) and fulvic acid (FA) from landfill. The EEMs of HAs at different landfill ages were characterized by two typical fluorescence chromophores with Ex/Em pairs at Ex=420-470 nm/Em=490-530 nm and Ex=345-375 nm/Em=450-465 nm. EEMs of FA were featured by other two distinctly different fluorophores with Ex/Em pairs at Ex=315-335 nm/Em=420-440 nm and Ex=255-275 nm/Em=425-455 nm. The results show that HA extracted from the refuse disposed in the year of 1989 was formed by connecting small-condensed aromatic structures with protein-like chains. Compared with HA extracted from the refuse disposed in the year of 1992, HA extracted from the refuse of 1996 had a higher fluorescence intensity and lower r(()(B)(,)(A)()) (the ratio of the fluorescence intensities of peak B and peak A) value. It contained low molar mass components, low aromatic condensation degree, and more easily oxidized substituents. This indicates that the landfill time strongly affects the EEMs characteristics of HA, and that the humification degree of HA increases with the landfill time. A red shift to a longer wavelength region and an increase of fluorescence intensity were observed when the concentration of HA was increased, suggesting that concentration had a great influence on the fluorescence characteristics of HAs. pH (2-12) also had significant effects on the fluorescence intensity, although it exerted no effect on the peak position of fluorescence of HA and FA. The results of FRI show that increasing concentration lead to more interactions among various structure components and that small molecular weight units tend to aggregate or be masked into more complicated and larger structures. The pH influence on the fluorescence intensity of HA seems mainly through molecular configuration, while the fluorescence intensity change with pH may be due to various substituents of FA. PMID:22104617

Xiaoli, Chai; Guixiang, Liu; Xin, Zhao; Yongxia, Hao; Youcai, Zhao

2012-03-01

256

Secreted protein acidic and rich in cysteine (SPARC) is upregulated by transforming growth factor (TGF)-? and is required for TGF-?-induced hydrogen peroxide production in fibroblasts  

PubMed Central

Background Idiopathic pulmonary fibrosis (IPF) is a poorly understood progressive disease characterized by the recurrent damage of alveolar epithelial cells as well as inappropriate expansion and activation of fibroblasts resulting in pronounced extracellular matrix (ECM) deposition. Although recent studies have indicated the involvement of secreted protein acidic and rich in cysteine (SPARC), a matricellular protein regulating ECM deposition, in the pathogenesis of fibrosis, factors regulating SPARC expression or roles of SPARC in fibrosis have not been fully elucidated. Results Among the profibrotic factors examined in cultured fibroblasts, we showed that SPARC expression was upregulated mainly by transforming growth factor (TGF)-?. We also showed that expression of SPARC in the lung was upregulated in the murine bleomycin-induced pulmonary fibrosis model, which was inhibited by TGF-? receptor I inhibitor. Knockdown of SPARC in fibroblasts using siRNA or treatment with the antioxidant N-acetylcysteine attenuated epithelial cell injury induced by TGF-?-activated fibroblasts in a coculture system. We also demonstrated that SPARC was required for hydrogen peroxide (H2O2) production in fibroblasts treated with TGF-?. Furthermore, TGF-? activated integrin-linked kinase (ILK), which was inhibited by SPARC siRNA. Knockdown of ILK attenuated extracellular H2O2 generation in TGF-?-stimulated fibroblasts. Our results indicated that SPARC is upregulated by TGF-? and is required for TGF-?-induced H2O2 production via activation of ILK, and this H2O2 production from fibroblasts is capable of causing epithelial cell injury. Conclusions The results presented in this study suggest that SPARC plays a role in epithelial damage in the IPF lung via enhanced H2O2 production from fibroblasts activated by TGF-?. Therefore, SPARC inhibition may prevent epithelial injury in IPF lung and represent a potential therapeutic approach for IPF.

2013-01-01

257

Temperature-dependent Fourier transform infrared spectroscopy and Raman mapping spectroscopy of phase-separation in a poly(3-hydroxybutyrate)-poly(L-lactic acid) blend.  

PubMed

Variable-temperature Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopic mapping measurements were applied to study the phase separation of a poly(3-hydroxybutyrate) (PHB)-poly(L-lactic acid) (PLA) (50 : 50 wt.%) polymer-blend film as a function of temperature between 25 and 175 °C. Because of the better band separation compared with the fundamental absorptions, the first overtones of the ?(C=O) bands of PHB and PLA were used to evaluate the temperature-dependent FT-IR images as PLA-PHB and PHB-PLA band-ratio contour plots, respectively. From the visualization of the band-ratio FT-IR images, it could be derived that even beyond the melting point of PLA (145 °C), the lateral position and the geometry of the PHB-rich and PLA-rich phases were retained up to 165 °C. Furthermore, the FT-IR images derived during and after the melting of PHB (174 °C) provided an interesting insight into the homogenization process of the polymer melt. By exploiting its higher lateral resolution, valuable additional information became available from the Raman mapping measurements. Based on the Raman data, the scenario of phase-separated PHB-rich and PLA-rich domains of about 50 ?m size, based on the FT-IR imaging measurements, had to be revised. Instead, the originally interpreted PHB-rich and PLA-rich domains are actually clusters of much smaller grains. Additionally, the Raman images measured in the same temperature interval revealed that the clusters of small PHB-rich grain structures aggregated as a function of temperature increase. These investigations prove that FT-IR and Raman imaging in combination with variable-temperature measurements can provide new (and so far unavailable) insights into structural phenomena of phase-separated polymer blends. PMID:23622432

Unger, Miriam; Sato, Harumi; Ozaki, Yukihiro; Fischer, Dieter; Siesler, Heinz W

2013-02-01

258

Transformation Station  

NSDL National Science Digital Library

Shapes are all over the place in geometry. One way we can move these shapes is with transformations. Use these games to help you practice and identify the three types of transformations: reflections, translations, and rotations. Just as a refresher, watch this video about transformational geometry: Gingerbread Transformer! When you are ready...start playing the games!! Take it to the court for Basketball Geometry! Once you type in your name and choose a player, pay attention to the coach for a review on the three types of transformations. While you play, ...

Stroud, Mrs.

2010-09-01

259

Fate of Transforming Deoxyribonucleic Acid After Uptake by Competent Bacillus subtilis: Phenotypic Characterization of Radiation-Sensitive Recombination-Deficient Mutants  

PubMed Central

A collection of 16 isogenic recombination-deficient strains of Bacillus subtilis isolated on the basis of sensitivity to methyl methane sulfonate (MMS) or mitomycin C (MC) were characterized phenotypically. All were found to be somewhat sensitive to ultraviolet irradiation, MC, and MMS. The mutants were all blocked in “late” steps in the transformation process and were provisionally grouped into four categories on the basis of the various properties examined. Class I mutants were deficient in transformation and heterologous transduction with phage PBS1 but were transducible with homologous donors at nearly the wild-type frequency. They were blocked in donor-recipient complex (DRC) formation but formed essentially normal amounts of double-strand fragments (DSF) and single-strand fragments (SSF). The class IIa strain was deficient in transformation and PBS1 transduction, and formed DRC which was normal by all available physical and biological criteria. Class IIb mutants were deficient in transformation and PBS1 transduction, and failed to form DRC. They did produce DSF and SSF. Class III mutants were deficient in transformation, were normal in PBS1 transduction, and formed DRC which was physically indistinguishable from that of the Rec+ parent although with slightly lowered donor-type transforming activity. Class IV strains were deficient in PBS1 transduction but were transformed at nearly the wild-type efficiency. None of the mutant strains was deficient in the adenosine triphosphate-dependent deoxyribonuclease.

Dubnau, D.; Davidoff-Abelson, R.; Scher, B.; Cirigliano, C.

1973-01-01

260

Biocompatible, pH-sensitive AB(2) Miktoarm Polymer-Based Polymersomes: Preparation, Characterization, and Acidic pH-Activated Nanostructural Transformation.  

PubMed

Motivated by the limitations of liposomal drug delivery systems, we designed a novel histidine-based AB(2)-miktoarm polymer (mPEG-b-(polyHis)(2)) equipped with a phospholipid-mimic structure, low cytotoxicity, and pH-sensitivity. Using "core-first" click chemistry and ring-opening polymerization, mPEG(2kDa)-b-(polyHis(29kDa))(2) was successfully synthesized with a narrow molecular weight distribution (1.14). In borate buffer (pH 9), the miktoarm polymer self-assembled to form a nano-sized polymersome with a hydrodynamic radius of 70.2 nm and a very narrow size polydispersity (0.05). At 4.2 µmol/mg polymer, mPEG(2kDa)-b-(polyHis(29kDa))(2) strongly buffered against acidification in the endolysosomal pH range and exhibited low cytotoxicity on a 5 d exposure. Below pH 7.4 the polymersome transitioned to cylindrical micelles, spherical micelles, and finally unimers as the pH was decreased. The pH-induced structural transition of mPEG(2kDa)-b-(polyHis(29kDa))(2) nanostructures may be caused by the increasing hydrophilic weight fraction of mPEG(2kDa)-b-(polyHis(29kDa))(2) and can help to disrupt the endosomal membrane through proton buffering and membrane fusion of mPEG(2kDa)-b-(polyHis(29kDa))(2). In addition, a hydrophilic model dye, 5(6)-carboxyfluorescein encapsulated into the aqueous lumen of the polymersome showed a slow, sustained release at pH 7.4 but greatly accelerated release below pH 6.8, indicating a desirable pH sensitivity of the system in the range of endosomal pH. Therefore, this polymersome that is based on a biocompatible histidine-based miktoarm polymer and undergoes acid-induced transformations could serve as a drug delivery vehicle for chemical and biological drugs. PMID:23002330

Yin, Haiqing; Kang, Han Chang; Huh, Kang Moo; Bae, You Han

2012-09-28

261

Animating Transformations  

NSDL National Science Digital Library

In most introductory linear algebra courses, prominent applications of transformations or mappings are moving (rotating, reflecting, translating), resizing (contracting, expanding), changing the shape (shearing, projecting) objects in the plane. A typical problem in such courses is to write the matrix of a transformation that changes points in such prescribed ways. The goal of this demo is to help students more easily visualize such transformations on a wide class of plane objects.

Roberts, Lila F.; Hill, David R.

2003-01-24

262

Collection of VLE data for acid gas - alkanolamine systems using Fourier transform infrared spectroscopy. Final report, September 29, 1990--September 30, 1996.  

National Technical Information Service (NTIS)

This report describes research from September 29, 1990 through September 30, 1996, involving the development a novel Fourier transform infrared (FTIR) spectroscopic apparatus and method for measuring vapor - liquid equilibrium (VLE) systems of carbon diox...

J. A. Bullin W. J. Rogers

1996-01-01

263

Transforming Schools.  

ERIC Educational Resources Information Center

Transforming the school as an organization requires change in all its components. More important, transformation connects the technical components with the human elements to create fundamental changes in the ways people perceive, think, and behave. With the community, a Wisconsin school board adopted a school district value statement to be used as…

Goens, George A.; Clover, Sharon I. R.

1992-01-01

264

Transformative Education.  

ERIC Educational Resources Information Center

The authors present the essential aspects composing the framework of transformative education. They discuss the general ends it promotes, the psychosocial theory upon which it is based, and the processes through which transformations are realized. Critical questions and educational virtues that serve as guidelines for implementation of…

Boyd, Robert D.; Myers, J. Gordon

1988-01-01

265

Acid rain  

Microsoft Academic Search

The causes and effects of acid rain are detailed. Sulfur dioxide and nitrogen dioxide emissions from anthropogenic sources are the primary causative agents. These emissions are transported over long distances and transformed into sulfates and nitrates and washed out of the atmosphere. Trends in acidity in precipitation water are reviewed for eastern portions of Canada and the U.S. Adverse effects

R. E. Ghelardi; B. L. Murphy

2009-01-01

266

Increase in nervonic acid content in transformed yeast and transgenic plants by introduction of a Lunaria annua L. 3- ketoacyl-CoA synthase ( KCS ) gene  

Microsoft Academic Search

Nervonic acid is a Very Long-Chain Monounsaturated Fatty Acid (VLCMFA), 24:1 ?15 (cis-tetracos-15-enoic acid) found in the seed oils of Lunaria annua, borage, hemp, Acer (Purpleblow maple) and Tropaeolum speciosum (Flame flower). However, of these, only the “money plant” (Lunaria annua L.) has been studied and grown sparingly for future development as a niche crop and the outlook has been

Yiming Guo; Elzbieta Mietkiewska; Tammy Francis; Vesna Katavic; Jennifer M. Brost; Michael Giblin; Dennis L. Barton; David C. Taylor

2009-01-01

267

[Transformation toughening  

SciTech Connect

In NiAl, we have succeeded in determining the complete Ginzburg-Landau strain free energy function necessary to model the cubic to tetragonal martensite transformation in a sample of any size. We believe that this is the first time that the parameters of a Ginzburg-Landau functional and the complete strain spinodal for any three-dimensional displacive transformation were used in simulating the transformation near a crack tip under Mode I loading; the transformation pattern and toughening are different from standard transformation toughening theories. Furthermore, the strain spinodal has an approximately conical shape which can be specified by two material dependent experimentally accessible parameters, rather than the ellipsoidal shape in standard theories. Stress induced martensitic transformation in a polycrystalline sample of NiAl was simulated. In the ZrO[sub 2] system, first principles calculations to determine the semi-empirical potentials for simulating the cubic-tetragonal and tetragonal-monoclinic transformations have been started by doing a more elaborate total energy calculation.In the Al[sub 2]0[sub 3] system, we have discovered that the first principles calculations and semi-empirical potentials have just been completed byanother group in England which we will use instead to base our molecular dynamics simulations on.

Rafa, M.J.

1993-04-19

268

Backlund Transformations as Canonical Transformations.  

National Technical Information Service (NTIS)

Toda and Wadati as well as Kodama and Wadati have shown that the Backlund transformations, for the exponential lattice equation, sine-Gordon equation, K-dV (Korteweg de Vries) equation and modified K-dV equation, are canonical transformations. It is shown...

A. Villani A. H. Zimerman

1977-01-01

269

Triple transformation  

NASA Astrophysics Data System (ADS)

A new business plan that enables policy transformation and resource mobilization at the national and international level, while improving access to resources, will allow the Green Climate Fund to integrate development goals and action on climate change.

Khan, Farrukh I.; Schinn, Dustin S.

2013-08-01

270

Transformation Golf  

NSDL National Science Digital Library

In this game students use the isometric transformations (sliding, flipping and turning) to sink a golf ball into a cup. There are nine holes in the course and learners are challenged to meet or break a par score.

2011-01-01

271

Transformation toughening  

Microsoft Academic Search

The critical stress-intensity factor,Kc, of materials containing tetragonal ZrO2 was found to decrease with increasing temperature and CeO2 alloying additions, as predicted by theory. The temperature dependence ofKc was related to the temperature dependence of the chemical free-energy change associated with tetragonal-monoclinic transformation. Good agreement with thermodynamic data available for pure ZrO2 was obtained when the size of the transformation

F. F. Lange

1982-01-01

272

Collection of VLE data for acid gas---alkanolamine systems using fourier transform infrared spectroscopy. Phase 2, October 1, 1991--September 30, 1992.  

National Technical Information Service (NTIS)

The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. Inadequate data for vapor--liquid equilibrium (VLE) ...

J. A. Bullin R. E. Frazier

1992-01-01

273

Collection of VLE data for acid gas-alkanolamine systems using Fourier transform infrared spectroscopy. Technical report, October 1, 1994--July 31, 1995.  

National Technical Information Service (NTIS)

The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. The natural gas industry requires vapor-liquid equil...

J. A. Bullin W. J. Rogers

1995-01-01

274

Pyrolysis of alanine and ?-aminoisobutyric acid: identification of less-volatile products using gas chromatography\\/Fourier transform infrared spectroscopy\\/mass spectrometry  

Microsoft Academic Search

In addition to volatile low-molecular-weight decomposition compounds, ?-aminoisobutyric acid (Aib) and alanine (Ala) pyrolysis at 500°C under nitrogen atmosphere leads to less-volatile products resulting from amino acid intermolecular condensation. The major pathway is the formation of cyclic dipeptides piperazine-2,5-diones with the yields of 1% for Aib and 68% for Ala. To identify other pyrolysis products, they have been extracted by

Vladimir A Basiuk; Rafael Navarro-González; Elena V Basiuk

1998-01-01

275

Identification of water-soluble heavy crude oil organic-acids, bases, and neutrals by electrospray ionization and field desorption ionization fourier transform ion cyclotron resonance mass spectrometry.  

PubMed

We identify water-soluble (23 degrees C) crude oil NSO nonvolatile acidic, basic, and neutral crude oil hydrocarbons by negative-ion ESI and continuous flow FD FT-ICR MS at an average mass resolving power, m/deltam50% = 550,000. Of the 7000+ singly charged acidic species identified in South American crude oil, surprisingly, many are water-soluble, and much more so in pure water than in seawater. The truncated m/z distributions for water-soluble components exhibit preferential molecular weight, size, and heteroatom class influences on hydrocarbon solubility. Acidic water-soluble heteroatomic classes detected at >1% relative abundance include O, O2, O3, O4, OS, O2S, O3S, O4S, NO2, NO3, and NO4. Parent oil class abundance does not directly relate to abundance in the water-soluble fraction. Acidic oxygen-containing classes are most prevalent in the water-solubles, whereas acidic nitrogen-containing species are least soluble. In contrast to acidic nitrogen-containing heteroatomic classes, basic nitrogen classes are water-soluble. Water-soluble heteroatomic basic classes detected at >1% relative abundance include N, NO, NO2, NS, NS2, NOS, NO2S, N2, N2O, N2O2, OS, O2S, and O2S2. PMID:17533826

Stanford, Lateefah A; Kim, Sunghwan; Klein, Geoffrey C; Smith, Donald F; Rodgers, Ryan P; Marshall, Alan G

2007-04-15

276

An application of derivative and continuous wavelet transforms to the overlapping ratio spectra for the quantitative multiresolution of a ternary mixture of paracetamol, acetylsalicylic acid and caffeine in tablets.  

PubMed

Quantitative multiresolution of tablets and ternary mixtures of paracetamol (PAR), acetylsalicylic acid (ASP) and caffeine (CAF) having strongly overlapping spectra was accomplished by two graphical transform methods as ratio spectra first derivative-zero crossing and ratio spectra-continuous wavelet transform-zero crossing (ratio spectra CWT-zero crossing) methods. In this study, ratio spectra derivative-zero crossing and ratio spectra CWT-zero crossing methods are based on the use of transformed signals of the ratio spectra and their calibration graphs were obtained by measuring the dA/dlambda and CWT amplitudes of the ratio spectra corresponding to zero crossing points. For the comparison purpose, PLS calibration method was applied to predict the content of the same mixtures containing the subject active compounds. The obtained calibrations were tested by using the synthetic mixtures and standard addition technique and they applied to the simultaneous determination of PAR, ASP and CAF in commercial pharmaceutical preparation. The obtained results were statistically compared with each other as well as those obtained by HPLC method and they showed good agreement. PMID:18969761

Dinç, Erdal; Ozdemir, Abdil; Baleanu, Dumitru

2005-01-15

277

Emissions of formaldehyde, acetic acid, methanol, and other trace gases from biomass fires in North Carolina measured by airborne Fourier transform infrared spectroscopy  

Microsoft Academic Search

Biomass burning is an important source of many trace gases in the global troposphere. We have constructed an airborne trace gas measurement system consisting of a Fourier transform infrared spectrometer (FTIR) coupled to a ``flow-through'' multipass cell (AFTIR) and installed it on a U.S. Department of Agriculture Forest Service King Air B-90. The first measurements with the new system were

R. J. Yokelson; J. G. Goode; D. E. Ward; R. A. Susott; R. E. Babbitt; D. D. Wade; I. Bertschi; D. W. T. Griffith; W. M. Hao

1999-01-01

278

SHARP transformation  

NASA Astrophysics Data System (ADS)

The U.S. Navy"s SHAred Reconnaissance Pod (SHARP) employs the Recon/Optical, Inc. (ROI) CA-279 dual spectral band (visible/IR) digital cameras operating from an F-18E/F aircraft to perform low-to-high altitude reconnaissance missions. SHARP has proven itself combat worthy, with a rapid transition from development to operational deployment culminating in a highly reliable and effective reconnaissance capability for joint forces operating in Operation Iraqi Freedom (OIF). The U.S. Navy"s intelligence, surveillance and reconnaissance (ISR) roadmap transforms the SHARP system from being solely an independent reconnaissance sensor to a node in the growing Joint ISR network. ROI and the U.S. Navy have combined their resources to ensure the system"s transformation continues to follow the ISR road map. Pre-planned product improvements (P3I) for the CA-270 camera systems will lead the way in that transformation.

Wyatt, Stephan

2004-08-01

279

Transformational leadership.  

PubMed

Rapid changes in the health care system have caused competition among institutions, as organizations are restructured to increase client satisfaction, resulting in the need for a new style of leadership. The transformational leader communicates the mission and vision of the organization and empowers others to effectively resolve conflicts that may arise with change. The health care team that can cope with changes and conflicts views restructuring as a positive transaction and approaches client satisfaction with energy and motivation. Institutions with transformational leadership are the ones that will survive the transition. PMID:8945261

Taccetta-Chapnick, M

1996-01-01

280

Molecular distribution, seasonal variation, chemical transformation and sources of dicarboxylic acids and related compounds in atmospheric aerosols at remote marine Gosan site, Jeju Island  

NASA Astrophysics Data System (ADS)

: A homologous series of C2-C12 ?, ?-dicarboxylic acids, ?-oxocarboxylic acids (C2-C9), pyruvic acid and ?-dicarbonyls (C2-C3) were detected in atmospheric aerosols collected between April 2003 and April 2004 from remote marine Gosan site (33°29? N, 126°16? E) located in Jeju Island, South Korea. They were determined using a GC-FID and GC/MS. Total diacid concentration ranged from 130 to 1911 ng m-3 (av. 642 ng m-3), whereas total oxoacid concentration ranged from 7 to 155 ng m-3 (av. 43 ng m-3), and pyruvic acid and ?-dicarbonyls ranged from 0.5 to 15 ng m-3 (av. 5 ng m-3) and 2-108 ng m-3 (av. 17.3 ng m-3), respectively. Oxalic (C2) acid was the most abundant in all seasons followed by malonic (C3) or succinic (C4) acid, and phthalic (Ph) acid. The concentration of diacids decreased with an increase in carbon number except for azelaic (C9) acid, which was more abundant than suberic (C8) acid. Glyoxylic acid was predominant ?-oxoacid contributing to 92% of total ?-oxoacid. Total diacids, oxoacids and dicarbonyls showed maximum concentrations in spring and occasionally in winter, while minimum concentrations were observed in summer. Air mass trajectory analysis suggests that either spring or winter maxima can be explained by strong continental outflow associated with cold front passages, while summer minima are associated with warm southerly flows, which transport clean marine air from low latitudes to Jeju Island. The comparison between total diacid concentration level of this study and other study results of urban and remote sites of East Asia reveals that Gosan site is more heavily influenced by the continental outflow from China. The seasonal variation of malonic/succinic (C3/C4), malic/succinic (hC4/C4), fumaric/maleic (F/M), oxalic/pyruvic (C2/Py) and oxalic/Glyoxal (C2/Gly) ratios showed maxima in summer due to an enhanced photo-production and degradation of diacids and related compounds. Throughout all seasons C3/C4 ratio at Gosan site, located between Chinese cities and Chichi-jima Island in Japan was observed higher than those in Chinese cities and lower than that of the Chichi-jima Island, pointing to the formation of diacid during long range transport. The lowest values of adipic/azelaic (C6/C9) and phthalic/azelaic (Ph/C9) were observed as a result of the overwhelming biogenic emission of the precursors (e.g., unsaturated fatty acids) of azelaic acid in summer.In this study, we will also discuss the sources and transport pathways of diacids and related compounds resolved using a hybrid receptor model, potential source contribution function (PSCF) and model results will be compared with available in-situ observations in East Asia.

Kundu, S.; Kawamura, K.; Lee, M.

2009-12-01

281

Metabolic diversity in biohydrogenation of polyunsaturated fatty acids by lactic acid bacteria involving conjugated fatty acid production  

Microsoft Academic Search

Lactobacillus plantarum AKU 1009a effectively transforms linoleic acid to conjugated linoleic acids of cis-9,trans-11-octadecadienoic acid (18:2) and trans-9,trans-11–18:2. The transformation of various polyunsaturated fatty acids by washed cells of L. plantarum AKU 1009a was investigated. Besides linoleic acid, ?-linolenic acid [cis-9,cis-12,cis-15-octadecatrienoic acid (18:3)], ?-linolenic acid (cis-6,cis-9,cis-12–18:3), columbinic acid (trans-5,cis-9,cis-12–18:3), and stearidonic acid [cis-6,cis-9,cis-12,cis-15-octadecatetraenoic acid (18:4)] were found to be transformed.

Shigenobu Kishino; Jun Ogawa; Kenzo Yokozeki; Sakayu Shimizu

2009-01-01

282

Transformations of high spin MnII and FeII polymeric pivalates in reactions with pivalic acid and o -phenylenediamines  

Microsoft Academic Search

The thermolysis and reactions of the polymeric high spin MnII and FeII complexes [Mn(-OOCBut)2(HOEt)]n (1) and [Fe(-OOCBut)2]n (3) with pivalic acid and o-phenylenediamines 1,2-(NH2)2C6H2R2 (R = H or Me) were studied. The synthesis of compound 1 performed with a deficiency of pivalate anions affords the antiferromagnetic chloropivalate polymer { (MeCN)(HOOCBut)(H2O)Mn5Cl(OH)(OOCBut)8MeCN}n. The reaction of 1 with an excess of pivalic acid

M. A. Kiskin; G. G. Aleksandrov; Zh. V. Dobrokhotova; V. M. Novotortsev; Yu. G. Shvedenkov; I. L. Eremenko

2006-01-01

283

DC Transformer.  

National Technical Information Service (NTIS)

A component level dc transformer is described in which no alternating currents or voltages are present. It operates by combining features of a homopolar motor and a homopolar generator, both de devices, such that the output voltage of a de power supply ca...

C. M. Ihlefeld R. C. Youngquist S. O. Starr

2013-01-01

284

Transforming Defense.  

National Technical Information Service (NTIS)

From April 17-20, 2001, the U.S. Army War College sponsored a major conference to examine the many issues and questions surrounding the transformation of the U.S. Armed Forces from a Cold War paradigm into a defense establishment ready to meet the complex...

C. C. Crane

2001-01-01

285

Exploring Transformations  

NSDL National Science Digital Library

In this activity, students will explore transformations of an absolute value function. Step by step instructions guide students in using graphing calculators to examine the effect that stretching and translating has on the coordinates of the graph. Teacher notes and a worksheet are also included to aid in teaching this lesson.

2011-11-25

286

Effective transformation of aldoximes to nitriles by dehydration with 2-methylene-1,3-dioxepane in the presence of a Lewis acid catalyst  

Microsoft Academic Search

The dehydration of aldoximes with 2-methylene-1,3-dioxepane (MDO) proceeds smoothly in the presence of a catalytic amount of Lewis acid such as scandium(III) triflate to give corresponding nitriles in moderate to high yields under mild conditions.

Shin-ichi Fukuzawa; Yasuhiro Yamaishi; Hideki Furuya; Keiji Terao; Fumiaki Iwasaki

1997-01-01

287

TERATOGENIC EFFECTS OF RETINOIC ACID ARE MODULATED IN MICE LACKING EXPRESSION OF EPIDERMAL GROWTH FACTOR AND TRANSFORMING GROWTH FACTOR-ALPHA  

EPA Science Inventory

Background: EGF and TGF regulate cell proliferation and differentiation in the embryo. The induction of cleft palate (CP) by all trans retinoic acid (RA) was associated with altered expression of TGF, EGF receptor and binding of EGF. The present study uses knockout (KO) mice to e...

288

Molecular level description of the sorptive fractionation of a fulvic Acid on aluminum oxide using electrospray ionization fourier transform mass spectrometry.  

PubMed

We addressed here, by means of electrospray ionization mass spectrometry (ESI-MS) with ultrahigh resolution, the molecular level fractionation of a reference fulvic acid (SRFA) during its sorption at an alumina surface, taken as a model for surfaces of natural aluminum oxide hydrates. Examination of ESI-MS spectra of a native SRFA solution and of supernatants collected in sorption experiments at acidic pH showed that the ?5700 compounds identified in the native solution were partitioned between the solution and alumina surface to quite varying degrees. Compounds showing the highest affinity for the surface were aromatic compounds with multiple oxygenated functionalities, polycyclic aromatic compounds depleted of hydrogen and carrying few oxygenated groups, and aliphatic compounds with very high O/C values, highlighting the fact that SRFA constituents were sorbed mainly via chemical sorption involving their oxygenated functionalities. We observed an inverse correlation between the degree of sorption of a molecule within a CH2 series and its number of CH2 groups and a positive correlation between the degree of sorption and the number of CO2 groups in a COO series, which was remarkable. These correlations provide evidence at the molecular scale that molecule acidity is the key parameter governing fulvic acid (FA) sorptive fractionation, and they are useful for predicting sorption of FA at a natural oxide surface. PMID:24905077

Galindo, Catherine; Del Nero, Mirella

2014-07-01

289

Transformations Journal  

NSDL National Science Digital Library

Different forms of communication have always had a tendency to transform interactions and everyday life in ways that have surprised people from many different backgrounds. Academics have long been interested in such dynamic transformations, and this electronic journal represents one of the responses to such processes. As their site notes, this journal is "dedicated to the exploration of ideas, issues and debates emerging out of contemporary global culture." Visitors to the site can read the complete version of every issue on the site, and they will be pleased to find such intriguing titles as "Rethinking Regionality", "Accidental Environments", and "Fleeing the City". Interested parties can also consult the site to learn about the journal's editorial board, their calls for papers, submission guidelines, and related links.

290

Pulse transformers  

Microsoft Academic Search

Pulse transformers capable of transmitting substantially rectangular voltage pulses, with durations of less than one microsecond, were developed for radar applications during World War II. Their primary functions were to match the impedances of high-power microwave radio-frequency electron-tube generators to electronic pulse generators and coaxial transmission cables, and to provide polarity reversal and impedance matching functions within pulse generator circuitry.

H. Lord

1971-01-01

291

Polyunsaturated fatty acid metabolism in Atlantic salmon (Salmo salar) undergoing parr-smolt transformation and the effects of dietary linseed and rapeseed oils  

Microsoft Academic Search

Duplicate groups of Atlantic salmon parr were fed diets containing either fish oil (FO), rapeseed oil (RO), linseed oil (LO) or linseed oil supplemented with arachidonic acid (20:4n-6; AA) (LOA) from October (week 0) to seawater transfer in March (week 19). From March to July (weeks 20–34) all fish were fed a fish oil-containing diet. Fatty acyl desaturation and elongation

D. R. Tocher; J. G. Bell; J. R. Dick; R. J. Henderson; F. McGhee; D. Michell; P. C. Morris

2000-01-01

292

Interaction of the transforming acidic coiled-coil 1 (TACC1) protein with ch-TOG and GAS41/NuBI1 suggests multiple TACC1-containing protein complexes in human cells.  

PubMed Central

Dysregulation of the human transforming acidic coiled-coil (TACC) proteins is thought to be important in the evolution of breast cancer and multiple myeloma. However, the exact role of these proteins in the oncogenic process is currently unknown. Using the full-length TACC1 protein as bait to screen a human mammary epithelial cDNA library, we have identified two genes that are also amplified and overexpressed in tumours derived from different cellular origins. TACC1 interacts with the C-terminus of both the microtubule-associated colonic and hepatic tumour overexpressed (ch-TOG) protein, and the oncogenic transcription factor glioma amplified sequence 41/NuMA binding protein 1 (GAS41/NuBI1; where NuMA stands for nuclear mitotic apparatus protein 1). This suggests that the TACC proteins can form multiple complexes, dysregulation of which may be an important step during tumorigenesis.

Lauffart, Brenda; Howell, Scott J; Tasch, Jason E; Cowell, John K; Still, Ivan H

2002-01-01

293

Development of a multichannel Fourier-transform spectrometer to measure weak chemiluminescence: Application to the emission of singlet-oxygen dimol in the decomposition of hydrogen peroxide with gallic acid and K 3[Fe(CN) 6  

NASA Astrophysics Data System (ADS)

A Fourier-transform spectrometer equipped with a Savart-plate polarization interferometer was developed for observation of weak chemiluminescence and applied to a measurement of emission spectra in the decomposition of hydrogen peroxide with gallic acid and K 3[Fe(CN) 6]. The band appearing at ˜580 nm in the chemiluminescence spectrum was assigned to the emission of singlet-oxygen dimol, the peak wavelength being shifted from that observed in the reaction of hydrogen peroxide with sodium hypochlorite, ˜633 nm. The band intensity was increased with the increasing concentration of K 3[Fe(CN) 6] up to ˜100 mM, and thereafter the peak wavelength was shifted from 580 to 700 nm with a decrease in the intensity.

Tsukino, Kazuo; Satoh, Toshihiro; Ishii, Hiroshi; Nakata, Munetaka

2008-05-01

294

The application of the yeast N-acetyltransferase MPR1 gene and the proline analogue L-azetidine-2-carboxylic acid as a selectable marker system for plant transformation  

PubMed Central

The yeast N-acetyltransferase MPR1 gene has previously been shown to confer resistance to the toxic proline analogue azetidine-2-carboxylic acid (A2C) in yeast and transgenic tobacco. Here experiments were carried out to determine if MPR1 and A2C can work as a selectable marker system for plant transformation. The MPR1 gene was inserted into a binary vector under the control of the cauliflower mosaic virus 35S promoter and nopaline synthase terminator, and transformed into tobacco via the Agrobacterium tumefaciens-mediated leaf disc method. A2C was applied in the selection medium to select for putative transformants. PCR analysis showed that 28.4% and 66.7% of the plantlets selected by 250??M and 300??M A2C were positive for the MPR1 gene, respectively. Southern and northern blot analysis and enzyme activity assay confirmed the stable gene incorporation, transcription, and translation of the MPR1 transgene in the transgenic plants. The transgene-carrying T1 progeny could be distinguished from the recessive progeny when grown on 400, 450, or 500??M A2C. Examination of the metabolism of 22 transgenic plants by gas chromatography–mass spectrometry profiling did not reveal any significant changes. In conclusion, the results demonstrate that MPR1/A2C is a safe and efficient selection system that does not involve microbial antibiotic or herbicide resistance genes. Recent studies showed that MPR1 can protect yeast against oxidative stresses by decreasing the accumulation of the proline catabolite ?1-pyrroline-5-carboxylate (P5C). However, H2O2 treatment resulted in contradictory responses among the five transgenic lines tested. Further experiments are required to assess the response of MPR1 transgenic plants under oxidative stress.

Tsai, Fei-Yi; Ulanov, Alexander; Widholm, Jack M.

2010-01-01

295

Hamlet's Transformation.  

NASA Astrophysics Data System (ADS)

William Shakespeare's Hamlet has much evidence to suggest that the Bard was aware of the cosmological models of his time, specifically the geocentric bounded Ptolemaic and Tychonic models, and the infinite Diggesian. Moreover, Shakespeare describes how the Ptolemaic model is to be transformed to the Diggesian. Hamlet's "transformation" is the reason that Claudius, who personifies the Ptolemaic model, summons Rosencrantz and Guildenstern, who personify the Tychonic. Pantometria, written by Leonard Digges and his son Thomas in 1571, contains the first technical use of the word "transformation." At age thirty, Thomas Digges went on to propose his Perfit Description, as alluded to in Act Five where Hamlet's age is given as thirty. In Act Five as well, the words "bore" and "arms" refer to Thomas' vocation as muster-master and his scientific interest in ballistics. England's leading astronomer was also the father of the poet whose encomium introduced the First Folio of 1623. His oldest child Dudley became a member of the Virginia Company and facilitated the writing of The Tempest. Taken as a whole, such manifold connections to Thomas Digges support Hotson's contention that Shakespeare knew the Digges family. Rosencrantz and Guildenstern in Hamlet bear Danish names because they personify the Danish model, while the king's name is latinized like that of Claudius Ptolemaeus. The reason Shakespeare anglicized "Amleth" to "Hamlet" was because he saw a parallel between Book Three of Saxo Grammaticus and the eventual triumph of the Diggesian model. But Shakespeare eschewed Book Four, creating this particular ending from an infinity of other possibilities because it "suited his purpose," viz. to celebrate the concept of a boundless universe of stars like the Sun.

Usher, P. D.

1997-12-01

296

Transformations - Dilation  

NSDL National Science Digital Library

In this interactive simulation, students are able to visualize and manipulate objects to understand dilation transformations. Students are able to adjust the center of dilation, rotate and move figures, change the scale factor to see what effect it has on the figures, add their own figures, and more. Across the top of the page, visitors will find links to activities to guide students as they explore the site, and more advanced activities involving computation are available in the Parent/Teacher section. The Instructions sections has detailed information for students and teachers alike on how to use the manipulative.

2003-01-01

297

Rotary Transformer  

NASA Technical Reports Server (NTRS)

None given. From first Par: Many spacecraft (S/C) and surface rovers require the transfer of signals and power across rotating interfaces. Science instruments, antennas and solar arrays are elements needing rotary power transfer for certain (S/C) configurations. Delivery of signal and power has mainly been done by using the simplest means, the slip ring approach. This approach, although simple, leaves debris generating noise over a period of time...The rotary transformer is a good alternative to slip rings for signal and power transfer.

McLyman, Colonel Wm. T.

1996-01-01

298

Novel action modality of the diterpenoid anisomelic acid causes depletion of E6 and E7 viral oncoproteins in HPV-transformed cervical carcinoma cells.  

PubMed

Cervical cancer, the second most common malignancy among women, is mainly caused by human papilloma virus (HPV) infection. In HPV-positive cervical cancer cells, the activity of p53 and the induction of p21 are inhibited by the HPV oncoproteins E6 and E7. Therefore, blocking the activity of E6 and E7 would serve as an important therapeutic target in these cancer cells. In this study, anisomelic acid (AA), a natural compound belonging to the same diterpenoid family of bioactive compounds as taxol, was found to deplete the E6 and E7 proteins in HPV-positive cervical cancer cells. Consequently, p53 and the p53-responsive gene, p21, were dramatically induced, leading to G2/M-phase cell cycle arrest. AA-mediated cell cycle arrest and p21 expression were canceled when p53 was down-regulated by p53-shRNA. AA also induced p53-independent intrinsic apoptosis by depletion of the cellular inhibitor of apoptosis protein 2 (cIAP2) whose proteosomal degradation is inhibited by E6. The in ovo chick embryo chorioallantoic membrane (CAM) assay showed that anisomelic acid inhibited the tumor growth of the cervical cancer SiHa cells. AA is revealed to hold a novel action modality based on specific targeting of the HPV oncoproteins, which restores p53-mediated growth arrest and induces apoptosis by terminating E6-mediated cIAP2 stabilization. PMID:24565908

Paul, Preethy; Rajendran, Senthil Kumar; Peuhu, Emilia; Alshatwi, Ali A; Akbarsha, Mohammad A; Hietanen, Sakari; Eriksson, John E

2014-05-15

299

An experimental investigation of Lewis acid-base interactions of liquid carbon dioxide using Fourier Transform Infrared (FT-IR) spectroscopy  

NASA Astrophysics Data System (ADS)

Presented here is an investigation into the solvent properties of liquid carbon dioxide by means of FT-IR spectroscopy. A high-pressure, circulation-type apparatus was designed and built specifically for this study. The spectra for the combination bands for carbon dioxide show that there are interactions between methanol and carbon dioxide. However, the spectra of the fundamental O-D vibration of deuterated methanol in liquid carbon dioxide indicate that there is no hydrogen bonding. Therefore. we conclude that the interactions between carbon dioxide and methanol are Lewis acid-base interactions rather than hydrogen bonding. This conclusion is supported by experiments where acetone is introduced into the CO2/methanol- d binary system. FT-IR measurements show that acetone hydrogen bonds with deuterated methanol.

Reilly, J. T.; Bokis, C. P.; Donohue, M. D.

1995-05-01

300

[The efficiency of hexose energy transformation into energy for volatile fatty acid production in the rumen of sheep fed diets containing sawdust].  

PubMed

Based on the production and interrelationship of volatile fatty acids (VFA), the mathematical method according to Orskov et al. (1968) was used to determine the efficiency of VFA production, and/or conversion of the energy of hexoses contained in fodders into VFA energy in rumen. VFA were separated by gas chromatography. The energy yield of VFA production in the rumen contents of wethers was averaged from the samples taken one, three and five hours after feeding. Whethers were fed 11 experimental diets, in which a part of bulk fodder (5-20%) was replaced by treated or untreated sawdust, and/or a diet without sawdust. The energy yield varied from 73.12 to 76.51% and the maximum values were achieved with the diets containing no sawdust. Compared with the diets with sawdust addition, the differences are statistically significant (P less than 0.05). The addition of the treated beech sawdust to the same diet, in comparison with untreated sawdust resulted in a higher energy yield of VFA production, however, with no statistical significance. The ratio of acetate to propionate was in a direct but negative relationship to energy yield of VFA production (n = 44, r = -0.905, P less than 0.001). Therefore the diets rich in cellulose, which cause an increase in the molar percentage of acetic acid and a subsequent increase in the ratio of acetate to propionate, might be responsible for the energy losses in the form of methane and can result in the decrease in total energy balance (Orskov et al., 1968). PMID:6815857

Baran, M; Jalc, D; Kalacnjuk, G I; Bod'a, K; Zelenák, I

1982-01-01

301

Quantitative Analysis of Long Chain Fatty Acids Present in a Type I Kerogen Using Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: Compared with BF3/MeOH Methylation/GC-FID  

NASA Astrophysics Data System (ADS)

Long chain fatty acids (LCFAs) are present in various natural samples and are easily detectable using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS) in negative ion mode. The capability of the ESI-FT-ICR-MS for quantifying LCFAs was evaluated by performing a standard addition followed by an internal standard methodology to several kerogen extracts using n-C20 fatty acid as standard. As the concentration of the standard increased, the magnitude of its peak ( m/z 311.29525) increased linearly but with two separate slopes, leaving the entire mass spectra relatively unchanged, which shows evidence of reproducibility. Response factors of other LCFAs are obtained using a standard addition approach. We employed five LCFA standards ( n-C15, n-C19, n-C24, n-C26, and n-C30) with different carbon numbers. This allowed us to determine the response factor of all fatty acids (with carbon number between 15 and 30) by plotting the slope of each standard versus its carbon number. With the observed response factors and use of the internal standard, the concentrations of LCFAs in four kerogen extracts were measured by ESI-FT-ICR-MS and compared with those from GC-FID. The carbon number distribution obtained by ESI-FT-ICR-MS matched well the GC-FID distribution (5%-50%) with the exception of C16 and C18, considering that ESI-FT-ICR-MS does not differentiate between normal and branched LCFAs, whereas GC-FID does. This allows one to quantitatively compare samples with a relatively similar matrix for specific compounds such as LCFAs with no need of time-consuming derivatization procedures. Moreover, the calibration can be extended to higher carbon numbers with ESI-FT-ICR-MS, beyond the capabilities of GC/MS.

Kamga, Albert W.; Behar, Fancoise; Hatcher, Patrick G.

2014-05-01

302

Hough Transform from the Radon Transform  

Microsoft Academic Search

An appropriate special case of a transform developed by J. Radon in 1917 is shown to have the major properties of the Hough transform which is useful for finding line segments in digital pictures. Such an observation may be useful in further efforts to generalize the Hough transform. Techniques for applying the Radon transform to lines and pixels are developed

Stanley R. Deans

1981-01-01

303

[Effect of alpha-lipoic acid on the sensitivity of transformed fibroblasts to lysis by natural killer cells. Comparison with NAC action].  

PubMed

The purpose of this study was to compare the effects of two antioxidants, alpha-lipoic acid (ALA) and N-acetylcysteine (NAC) on the sensitivity of 3T3-SV40 fibroblasts to lytic activity of natural killer (NK) cells. ALA (1.25 mM) reduced significantly the fibroblast sensitivity in several hours, whereas NAC (10 mM) did not change it. Subsequent removal of the antioxidants from the cultivation medium resulted in gradual recovery of the sensitivity in the case of ALA and in complete loss of it in the case of NAC. Inactivation of gelatinase MMP-2 (matrix metalloproteinase) using pretreatment of the cells with the inhibitor of MMP, G6001, or specific antibodies to MMP-2 or MMP-9 resulted in decrease of 3T3-SV40 sensitivity to NK cells activity. This effect was similar to that of ALA, not to the NAC one. Pretreatment of NK cells with G6001 did not influence their lytic activity. The results obtained demonstrate that the direct antioxidant, NAC (having reduced thiol groups), and the indirect one, ALA (reducing thiol groups and acting as a direct antioxidant only inside the cell) activate principally different intracellular signal pathways. However, both NAC and ALA pathway includes inactivation of MMP-2. PMID:19566031

Filatova, N A; Kirpichnikova, K M; Vakhromova, E A; Gamale?, I A

2009-01-01

304

Collection of VLE data for acid gas---alkanolamine systems using fourier transform infrared spectroscopy. Phase 2, October 1, 1991--September 30, 1992  

SciTech Connect

The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. Inadequate data for vapor--liquid equilibrium (VLE) hinder the industry from converting operations to more energy efficient amine mixtures and conserving energy. Some energy reductions have been realized in the past decade by applying such amine systems as ``hindered`` amines, methyldiethanolamine (MDEA), and MDEA based amine mixtures. However, the lack of reliable and accurate fundamental VLE data impedes the commercial application of these more efficient alkanolamine systems. The first project objective is to improve the accuracy of vapor--liquid equilibrium measurements at low hydrogen sulfide concentrations. The second project objective is to measure the VLE for amine mixtures. By improving the accuracy of the VLE measurements on MDEA and mixtures with other amines, energy saving can be quickly and confidently implemented in the many existing absorption units already in use. If about 25% of the existing 95.3 billion SCFD gas purification capacity is converted to these new amine systems, the energy savings are estimated to be about 3 {times} 10{sup 14} BTU/yr.

Bullin, J.A.; Frazier, R.E.

1992-12-01

305

Collection of VLE data for acid gas-alkanolamine systems using Fourier transform infrared spectroscopy. Phase 1, September 29, 1990--September 30, 1991  

SciTech Connect

The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. Inadequate data for vapor -- liquid equilibrium (VLE) hinder the industry from converting operations to more energy efficient amine mixtures and conserving energy. Some energy reductions have been realized in the past decade by applying such amine systems as ``hindered`` amines, methyldiethanolamine (MDEA), and MDEA based amine mixtures. However, the lack of reliable and accurate fundamental VLE data impedes the commercial application of these more efficient alkanolamine systems. The first project objective is to improve the accuracy of vapor -- liquid equilibrium measurements at low hydrogen sulfide concentrations. The second project objective is to measure the VLE for amine mixtures. By improving the accuracy of the VLE measurements on MDEA and mixtures with other amines, energy saving can be quickly and confidently implemented in the many existing absorption units already in use. If about 25% of the existing 95.3 billion SCFD gas purification capacity is converted to these new amine systems, the energy savings are estimated to be about 3 {times} 10{sup 14} BTU/yr.

Bullin, J.A.; Frazier, R.E.

1991-09-01

306

Collection of VLE data for acid gas-alkanolamine systems using Fourier transform infrared spectroscopy. Technical report, October 1, 1994--July 31, 1995  

SciTech Connect

The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. The natural gas industry requires vapor-liquid equilibrium (VLE) data to develop more energy efficient amine mixtures. Some energy reductions have been realized in the past decade by applying such amine systems as hindered amines, methyldiethanolamine (MDEA), and MDEA based amine mixtures. However, the lack of reliable and accurate VLE data impedes the commercial application of these more efficient alkanolamine systems. The first objective of this project is to improve the accuracy of vapor-liquid equilibrium measurements at low hydrogen sulfide concentrations. The second objective is to make VLE measurements for amine mixtures. By improving the accuracy of the VLE data on MDEA and other amines, energy savings can be implemented in the many existing absorption units already in use. If about 25% of the existing 95.3 billion SCFD gas purification capacity is converted to these new amine systems, the energy saved is estimated to be 3 {times} 10{sup 14} BTU/yr. 14 refs., 31 figs., 12 tabs.

Bullin, J.A.; Rogers, W.J.

1995-08-01

307

Investigation of mediated oxidation of ascorbic acid by ferrocenemethanol using large-amplitude Fourier transformed ac voltammetry under quasi-reversible electron-transfer conditions at an indium tin oxide electrode.  

PubMed

The ability of the technique of large-amplitude Fourier transformed (FT) ac voltammetry to facilitate the quantitative evaluation of electrode processes involving electron transfer and catalytically coupled chemical reactions has been evaluated. Predictions derived on the basis of detailed simulations imply that the rate of electron transfer is crucial, as confirmed by studies on the ferrocenemethanol (FcMeOH)-mediated electrocatalytic oxidation of ascorbic acid. Thus, at glassy carbon, gold, and boron-doped diamond electrodes, the introduction of the coupled electrocatalytic reaction, while producing significantly enhanced dc currents, does not affect the ac harmonics. This outcome is as expected if the FcMeOH (0/+) process remains fully reversible in the presence of ascorbic acid. In contrast, the ac harmonic components available from FT-ac voltammetry are predicted to be highly sensitive to the homogeneous kinetics when an electrocatalytic reaction is coupled to a quasi-reversible electron-transfer process. The required quasi-reversible scenario is available at an indium tin oxide electrode. Consequently, reversible potential, heterogeneous charge-transfer rate constant, and charge-transfer coefficient values of 0.19 V vs Ag/AgCl, 0.006 cm s (-1) and 0.55, respectively, along with a second-order homogeneous chemical rate constant of 2500 M (-1) s (-1) for the rate-determining step in the catalytic reaction were determined by comparison of simulated responses and experimental voltammograms derived from the dc and first to fourth ac harmonic components generated at an indium tin oxide electrode. The theoretical concepts derived for large-amplitude FT ac voltammetry are believed to be applicable to a wide range of important solution-based mediated electrocatalytic reactions. PMID:18666783

Lertanantawong, Benchaporn; O'Mullane, Anthony P; Zhang, Jie; Surareungchai, Werasak; Somasundrum, Mithran; Bond, Alan M

2008-09-01

308

Complex BIFORE transform  

Microsoft Academic Search

Complex BIFORE (Binary FOurior REpresentation) transform belongs to the family of discrete orthogonal transformations and is analogous to discrete Fourier transform (DFT) when dealing with complex inputs. For real inputs, complex BIFORE transform (CBT) reduces to BIFORE or Hadamard transform (BT or HT) whose bases are Walsh functions. BT has been applied in several phases of information processing and sequency

K. R. RAO; N. AHMED

1971-01-01

309

Fast Polar Harmonic Transforms  

Microsoft Academic Search

Polar Harmonic Transform (PHT) is termed to represent a set of transforms those kernels are basic waves and harmonic in nature. PHTs consist of Polar Complex Exponential Transform (PCET), Polar Cosine Transform (PCT) and Polar Sine Transform (PST). They are proposed to represent invariant image patterns for two dimensional image retrieval and pattern recognition tasks. They are demonstrated to show

Zhuo Yang; Sei-ichiro Kamata

2010-01-01

310

Hough transform from the radon transform.  

PubMed

An appropriate special case of a transform developed by J. Radon in 1917 is shown to have the major properties of the Hough transform which is useful for finding line segments in digital pictures. Such an observation may be useful in further efforts to generalize the Hough transform. Techniques for applying the Radon transform to lines and pixels are developed through examples, and the appropriate generalization to arbitrary curves is discussed. PMID:21868933

Deans, S R

1981-02-01

311

Hadamard transform imaging  

SciTech Connect

We have constructed a Hadamard transform Raman microscopic imaging system, and have developed it to a high definition (64K pixel) technique. We have demonstrated multispectral Raman imaging and developed the first three-dimensional (digital confocal) Raman imaging. We have explored the systematic errors in Hadamard multiplexing techniques and developed corrections. We have used our Raman microscope techniques to explore defect distributions on graphite electrodes and damage effects on SERS-activated silver electrodes. We have used the microprobe capabilities of our instrument to investigate the kinetics of polyacrylamide formation in electrolysis capabilities. We have worked closely with a manufacture of holographic displays to develop and incorporate holographic filters and holographic beam splitters into Raman spectrographs and microscopes. Finally, we have developed Hadamard multiplexing techniques for densitometric measurements of protein or nucleic acid blots.

Morris, M.D.

1992-01-01

312

Army Maintenance System Transformation.  

National Technical Information Service (NTIS)

The first official use of the term 'transformation' is often attributed to the document 'Joint Vision 2010,' which was published in 1996. Logistics, an integral component of this transformation, is adjusting as well. As a part of logistics transformation,...

F. V. Gilbertson

2006-01-01

313

Toward Machine Learning Through Genetic Code-like Transformations  

Microsoft Academic Search

The gene expression process in nature involves several representation transformations of the genome. Translation is one among them; it constructs the amino acid sequence in proteins from the nucleic acid-based mRNA sequence. Translation is defined by a code book, known as the universal genetic code. This paper explores the role of genetic code and similar representation transformations for enhancing the

Hillol Kargupta; Samiran Ghosh

2002-01-01

314

Assessment of FLD-based algorithms for the retrieval of vegetation solar-induced fluorescence from the in-filling of the telluric O2-A and O2-B lines  

NASA Astrophysics Data System (ADS)

This study evaluates the performances of different algorithms for the retrieval of solar induced fluorescence of vegetation in both the telluric O2-A and O2-B bands of the atmospheric molecular oxygen, respectively at 760 nm and 687 nm. In particular, we evaluated the performances of three algorithms amongst those already applied by the scientific community: two of them are based on the use of two or three spectral bands (sFLD and 3FLD methods), while the third one exploits the information content of all the spectral channels in certain bands by applying a polynomial model for fluorescence and reflectance (SFM method). These were applied to a synthetic set of fluorescence data corresponding to different types of vegetation. The main technical specifications of the spectroradiometer have been outlined in terms of three different airborne operating scenarios, addressing different flight altitudes and speeds chosen on the basis of typical platforms suitable for operation from low-medium altitudes. The results underline that the high spectral resolution of the instrument plays a fundamental role for the determination of the value of fluorescence with a good precision and accuracy, as expected. Nevertheless, the extraction of the value of fluorescence in the O2-A band is less critical than in the O2-B band and, specifically, it is less sensitive to the spectral resolution of the spectroradiometer. Even at low spectral resolutions, however, the retrieval algorithms based on polynomial fitting provided better results than methods based on the use of spectral bands.

Palombi, Lorenzo; Di Ninni, Paola; Guzzi, Donatella; Lognoli, David; Nardino, Vanni; Pippi, Ivan; Raimondi, Valentina

2013-10-01

315

Levulinic acid in organic synthesis  

Microsoft Academic Search

Data concerning the methods of synthesis, chemical transformations and application of levulinic acid are analysed and generalised. The wide synthetic potential of levulinic acid, particularly as a key compound in the synthesis of various heterocyclic systems, saturated and unsaturated ketones and diketones, difficultly accessible acids and other compounds is demonstrated. The accessibility of levulinic acid from hexose-containing wood-processing and agricultural

Boris V Timokhin; V A Baransky; G D Eliseeva

1999-01-01

316

Induction of transforming growth factor-beta autocrine activity by all-trans-retinoic acid and 1 alpha,25-dihydroxyvitamin D3 in NRP-152 rat prostatic epithelial cells.  

PubMed

Retinoids and vitamin D analogues are known to inhibit the proliferation of a variety of cells in culture and prevent the formation of certain tumors in mammals. Although it is well established that these hormones control the transcription of many genes upon binding to and activating specific nuclear receptors, the mechanisms by which they prevent cancer are as yet poorly understood. In this study the role of the transforming growth factor-beta (TGF-beta) growth inhibitors, in promoting the biological activities of all-trans-retinoic acid (RA) and 1 alpha,25-dihydroxyvitamin D3 (1,25-(OH)2D3) was studied in NRP-152 cells, a nontumorigenic epithelial line derived from rat dorsal-lateral prostate. Inhibition of growth by nanomolar concentrations of RA was associated with an increase in both mRNA and protein for all three TGF-beta isoforms, with greater and much earlier increases for TGF-beta s 2 and 3 (5.5 h) than for TGF-beta 1 (24 h). A monoclonal antibody against TGF-beta and TGF-beta 1 latency associated peptide (LAP), both of which neutralize all three TGF-beta isoforms, each block the ability of RA to inhibit growth of NRP-152 cells by > 95%. Neutralization of growth inhibition by isoform-specific antibodies suggested that all three TGF-beta s are involved in this effect. The ability of RA to upregulate fibronectin and thrombospondin expression in NRP-152 cells was also blocked by the monoclonal antibody. 1,25-(OH)2D3, which also induced TGF-beta s 2 and 3 but not TGF-beta 1, and their respective mRNAs, also induced fibronectin and thrombospondin through induction of TGF-beta. Thus, autocrine production of TGF-beta s may be a significant part of the mechanisms by which RA and 1,25-(OH)2D3 promote cellular differentiation. PMID:8557772

Danielpour, D

1996-01-01

317

Hadamard transform image coding  

Microsoft Academic Search

The introduction of the fast Fourier transform algorithm has led to the development of the Fourier transform image coding technique whereby the two-dimensional Fourier transform of an image is transmitted over a channel rather than the image itself. This devlopement has further led to a related image coding technique in which an image is transformed by a Hadamard matrix operator.

W. K. Pratt; J. Kane; H. C. Andrews

1969-01-01

318

RM2: Transform operations  

NASA Technical Reports Server (NTRS)

The two-dimensional transform used in the research TV source encoder, RM2 is discussed. It is shown that both conceptually and in terms of the number of required computations, the RM2 transform is considerably simpler than the Fast Hadamard Transform. The latter can in fact be generated by extending the RM2 transform.

Rice, R. F.

1974-01-01

319

Fast Discrete Curvelet Transforms  

Microsoft Academic Search

This paper describes two digital implementations of a new mathematical transform, namely, the second generation curvelet transform (12, 10) in two and three dimensions. The first digital transformation is based on unequally-spaced fast Fourier transforms (USFFT) while the second is based on the wrapping of specially selected Fourier samples. The two implementations essentially dier by the choice of spatial grid

Emmanuel Cande?s; Laurent Demanet; David Donoho; Lexing Ying

2006-01-01

320

Transform domain LMS algorithm  

Microsoft Academic Search

The concept of transform domain adaptive filtering is introduced. In certain applications, filtering in the transform domain results in great improvements in convergence rate over the conventional time-domain adaptive filtering. The relationship between several existing frequency domain adaptive filtering algorithms is established. Applications of the discrete Fourier transform (DFT) and the discrete cosine transform (DCT) domain adaptive filtering algorithms in

S. Narayan; A. M. Peterson; M. J. Narasimha

1983-01-01

321

Discrete Cosine Transform  

Microsoft Academic Search

A discrete cosine transform (DCT) is defined and an algorithm to compute it using the fast Fourier transform is developed. It is shown that the discrete cosine transform can be used in the area of digital processing for the purposes of pattern recognition and Wiener filtering. Its performance is compared with that of a class of orthogonal transforms and is

N. Ahmed; T. Natarajan; K. R. Rao

1974-01-01

322

Assessing the Hartley transform  

Microsoft Academic Search

The fast algorithm for the (real) Hartly transform is discussed in relation to the established fast algorithm for the (complex) Fourier transform. The two transforms are compared by timing comparably written programs on a given machine, and the discipline of timing is discussed as an adjunct to complexity analysis. With real data, one Hartley transform program can economically replace such

R. N. Bracewell

1990-01-01

323

Transforming the Way We Teach Function Transformations  

ERIC Educational Resources Information Center

In this article, the authors discuss "function," a well-defined rule that relates inputs to outputs. They have found that by using the input-output definition of "function," they can examine transformations of functions simply by looking at changes to input or output and the respective changes to the graph. Applying transformations to the input…

Faulkenberry, Eileen Durand; Faulkenberry, Thomas J.

2010-01-01

324

Characterization of acid tars  

Microsoft Academic Search

Acid tars from the processing of petroleum and petrochemicals using sulfuric acid were characterized by gas chromatography\\/mass spectrometry (GC\\/MS), inductively coupled plasma\\/optical emission spectrometry (ICP\\/OES), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectrometry, and scanning electron microscopy\\/energy dispersive X-ray (SEM\\/EDX) micro-analysis. Leaching of contaminants from the acid tars in 48h batch tests with distilled water at a liquid-to-solid ratio

Sunday A. Leonard; Julia A. Stegemann; Amitava Roy

2010-01-01

325

Immunosuppression in Hamsters with Progressive Visceral Leishmaniasis Is Associated with an Impairment of Protein Kinase C Activity in Their Lymphocytes That Can Be Partially Reversed by Okadaic Acid or Anti-Transforming Growth Factor ? Antibody  

PubMed Central

Progressive visceral infection of golden hamsters by Leishmania donovani amastigotes led to gradual impairment of the proliferative responses of their splenic or peripheral blood mononuclear cells (SPMC or PBMC, respectively) to in vitro stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin (Io). Removal of macrophage-like adherent cells from SPMC or PBMC of infected animals (I-SPMC or I-PBMC) was earlier shown to restore almost completely their lymphoproliferative responses to PMA plus Io. The present study was directed to evaluate the status of protein kinase C (PKC), a molecule(s) known to play a key role in the lymphoproliferative process. Our results demonstrate that PKC activities (Ca2+, phosphatidyl serine, and diacyl glycerol dependent) in the cytosolic fraction of untreated nonadherent I-SPMC or I-PBMC as well as in the membrane fraction of PMA-treated cells were decreased significantly relative to those for normal controls. However, removal of adherent cells from I-SPMC or I-PBMC and subsequent overnight in vitro cultivation of nonadherent cells (lymphocytes) resulted in significant restoration of PKC activity in the cytosolic or membrane fraction of untreated or PMA-treated cells, respectively. Partial, though significant, restoration of PKC activity could also be achieved in the membrane fraction of PMA-treated cells following overnight in vitro treatment of I-SPMC or I-PBMC with the Ser/Thr phosphatase inhibitor okadaic acid (OA) or an anti-transforming growth factor ? (anti-TGF-?) neutralizing antibody. These results correlated well with the ability of OA or the anti-TGF-? antibody to restore the lymphoproliferative response of I-SPMC or I-PBMC following stimulation with PMA plus Io. Interestingly enough, immunoblotting experiments failed to show any reduction in the level or translocation (following PMA treatment) of conventional PKC isoforms in the SPMC or PBMC of infected animals compared to those of normal controls. The results presented in this study suggest that the adherent cells generated in the SPMC or PBMC of infected animals exert a suppressive effect on the proliferative response of nonadherent cells (lymphocytes) which is likely to be mediated through the downregulation of the activation pathway involving PKC and its downstream molecules such as mitogen-activated protein kinases. Further, the observed suppression of PKC activity and subsequent lymphoproliferative responses can be attributed to alternations in the intracellular phosphorylation-dephosphorylation events. The relevance of these results is discussed in relation to the role of TGF-?, levels of which are known to be elevated in visceral leishmaniasis.

Mookerjee, Ananda; Sen, Parimal C.; Ghose, Asoke C.

2003-01-01

326

Direct Current Transformer.  

National Technical Information Service (NTIS)

A direct current transformer was built in which the primary consists of an elongated strip of superconductive material, across the ends of which is applied a direct current potential. Parallel and closely spaced to the primary is positioned a transformer ...

E. W. Urban S. M. Khanna

1977-01-01

327

Equations For Rotary Transformers  

NASA Technical Reports Server (NTRS)

Equations derived for input impedance, input power, and ratio of secondary current to primary current of rotary transformer. Used for quick analysis of transformer designs. Circuit model commonly used in textbooks on theory of ac circuits.

Salomon, Phil M.; Wiktor, Peter J.; Marchetto, Carl A.

1988-01-01

328

The Adaptive Hough Transform  

Microsoft Academic Search

We introduce the Adaptive Hough Transform, AHT, as an efficient way of implementing the Hough Transform, HT, method for the detection of 2-D shapes. The AHT uses a small accumulator array and the idea of a flexible iterative \\

John Illingworth; Josef Kittler

1987-01-01

329

Pulse Transformer Design Study.  

National Technical Information Service (NTIS)

This final report describes the design, development of fabrication techniques, fabrication, and testing of two uniform field, air core pulse transformers. The described transformer design minimizes the volume of dielectric material, which provides turn-to...

H. Aslin

1977-01-01

330

Transformations in Solidified Gases.  

National Technical Information Service (NTIS)

Transformations in solidified gases have been studied in very few laboratories yet they are governed by factors of wide scientific interest, some of which are very different from those involved in the commonly studied transformations of metallic substance...

C. S. Barrett

1968-01-01

331

Discrete radon transform  

Microsoft Academic Search

This paper describes the discrete Radon transform (DRT) and the exact inversion algorithm for it. Similar to the discrete Fourier transform (DFT), the DRT is defined for periodic vector-sequences and studied as a transform in its own right. Casting the forward transform as a matrix-vector multiplication, the key observation is that the matrix-although very large-has a block-circulant structure. This observation

GREGORY BEYLKIN

1987-01-01

332

Optical Hartley transforms  

Microsoft Academic Search

The two-dimensional Hartley transform is of particular interest not only as a tool for analysis and processing of images and other two-dimensional functions, but because it can be implemented optically without introducing the phase ambiguities associated with intensity-only observations of Fourier transforms. The Hartley transform property of producing real transforms from real inputs means that square law detection introduces only

J. D. Villasenor

1994-01-01

333

Golden Hadamard Transform Matrices  

Microsoft Academic Search

Here is introducing a new transform known as the Golden Hadamard Transform whose kernel contains just the Golden Mean. An analytical comparison is made with the Walsh-Hadamard Transform to use in various applications such as coding, error correction codes etc.

Sos Agaian; Hakob Sarukhanyan; Jaakko Astola

334

Stationary Hadamard Transform Spectrometry  

Microsoft Academic Search

Two novel applications of a stationary electro -optic shutter have been successfully developed for use in Hadamard transform spectrometry. The first of these combines interferometric and Hadamard transform techniques for a spectrometric instrument offering advantages over conventional spectrometers. A Hadamard transform encoding mask is incorporated into a multiple-beam Fizeau interferometer design, allowing the use of a single detector element rather

James David Tate

1991-01-01

335

The pulse sorting transform  

Microsoft Academic Search

A modification of conventional Fourier transforms is presented. This modification is called the pulse sorting transform (PST) and is useful in extracting information from signals comprised of interleaved pulse trains. A brief derivation of the PST from the conventional transform is presented, followed by theorems that describe the PST's properties. Several examples of how the PST can be an effective

K. C. Overman; D. F. Mix; J. A. Lookadoo

1990-01-01

336

Transformer Core Clamp.  

National Technical Information Service (NTIS)

This report describes a transformer core clamp that increases both the clamping force applied to a center leg of the transformer core and the shock resistance of the transformer core. The clamp is constructed with opposed clamp plates on the outward facin...

B. Allen N. Williams

1980-01-01

337

Transformations - Composition (NLVM)  

NSDL National Science Digital Library

This Java applet enables learners to explore compositions of two transformations (among sliding, flipping and turning) both informally and within a coordinate system. Students select and compose shapes and manipulate the transformations to see the effect on a transformed image. Links to instructions, activities and teacher/parent information are included.

2011-01-01

338

The Transformation of Suffering  

Microsoft Academic Search

This article offers reflections on The Passion of the Lord, edited by James A. Noel and Matthew V. Johnson. The title “The Transformation of Suffering” refers not only to the transformations emerging from the epic suffering endured by Jesus and by peoples of the African diaspora, but to the ways each of us may be spiritually transformed by the crucible

Liza J. Rankow

2006-01-01

339

On SYZ mirror transformations  

Microsoft Academic Search

In this expository paper, we discuss how Fourier-Mukai-type transformations, which we call SYZ mirror transformations, can be applied to provide a geometric understanding of the mirror symmetry phenomena for semi-flat Calabi-Yau manifolds and toric Fano manifolds. We also speculate the possible applications of these transformations to other more general settings.

Kwokwai Chan; Naichung Conan Leung

2008-01-01

340

Modulating the acidity: highly acidic Brønsted acids in asymmetric catalysis.  

PubMed

Recently, chiral highly acidic Brønsted acids have emerged as powerful catalysts for enantioselective C-C and C-X bond-forming reactions. Their strong acidity renders them valuable tools for the activation of imines, carbonyl compounds, and other weakly basic substrates. As a result, new perspectives are opened and highly stereoselective transformations based on the concept of chiral contact-ion-pair catalysis can be realized. This Minireview gives an overview of the design and application of these new organocatalysts and presents recent results in this rapidly growing field. PMID:21678531

Rueping, Magnus; Nachtsheim, Boris J; Ieawsuwan, Winai; Atodiresei, Iuliana

2011-07-18

341

Note: Tesla transformer damping.  

PubMed

Unexpected heavy damping in the two winding Tesla pulse transformer is shown to be due to small primary inductances. A small primary inductance is a necessary condition of operability, but is also a refractory inefficiency. A 30% performance loss is demonstrated using a typical "spiral strip" transformer. The loss is investigated by examining damping terms added to the transformer's governing equations. A significant alteration of the transformer's architecture is suggested to mitigate these losses. Experimental and simulated data comparing the 2 and 3 winding transformers are cited to support the suggestion. PMID:22852736

Reed, J L

2012-07-01

342

Note: Tesla transformer damping  

NASA Astrophysics Data System (ADS)

Unexpected heavy damping in the two winding Tesla pulse transformer is shown to be due to small primary inductances. A small primary inductance is a necessary condition of operability, but is also a refractory inefficiency. A 30% performance loss is demonstrated using a typical ``spiral strip'' transformer. The loss is investigated by examining damping terms added to the transformer's governing equations. A significant alteration of the transformer's architecture is suggested to mitigate these losses. Experimental and simulated data comparing the 2 and 3 winding transformers are cited to support the suggestion.

Reed, J. L.

2012-07-01

343

Fractional finite Fourier transform  

NASA Astrophysics Data System (ADS)

We show that a fractional version of the finite Fourier transform may be defined by using prolate spheroidal wave functions of order zero. The transform is linear and additive in its index and asymptotically goes over to Namias's definition of the fractional Fourier transform. As a special case of this definition, it is shown that the finite Fourier transform may be inverted by using information over a finite range of frequencies in Fourier space, the inversion being sensitive to noise. Numerical illustrations for both forward (fractional) and inverse finite transforms are provided.

Khare, Kedar; George, Nicholas

2004-07-01

344

The protective effects of omega-6 fatty acids in experimental autoimmune encephalomyelitis (EAE) in relation to transforming growth factor-beta 1 (TGF-?1) up-regulation and increased prostaglandin E2 (PGE2) production  

PubMed Central

Polyunsaturated fatty acids are known to affect the immune response and administration of the omega-6 fatty acid linoleic acid has been reported to be beneficial in multiple sclerosis (MS) and EAE. In this study we have investigated the effects of oral feeding of plant lipid rich in the omega-6 fatty acid gamma-linolenic acid from Borago officinalis on acute and relapse disease and the immune response in EAE using SJL mice. EAE was induced by an encephalitogenic peptide (92–106) of myelin oligodendrocyte glycoprotein (MOG), and mice were fed the plant lipid daily from 7 days after EAE induction to assess the effects on acute disease and from day 25 to assess the effects on disease relapse. The clinical incidence and histological manifestations of acute EAE, and the clinical relapse phase of chronic relapsing EAE (CREAE) were markedly inhibited by omega-6 fatty acid feeding. A significant increase in the production of TGF-?1 in response to concanavalin A (Con A) at day 13 and a significant increase in TGF-?1 and PGE2 to Con A, PPD and MOG peptide (92–106) at day 21 were detected in spleen mononuclear cells from fatty acid-fed mice. There was no difference in interferon-gamma, IL-4 and IL-2 production between the fatty acid?fed and control groups. Significantly higher TGF-? mRNA expression was found in the spleens of omega-6 fatty acid-fed mice at day 21. There were no differences in spleen cell proliferative response to Con A, PPD and MOG peptide (92–106). Biochemical analysis of spleen cell membrane fatty acids revealed significant increases in the eicosanoid precursor fatty acids dihomo-?-linolenic acid and arachidonic acid in response to gamma-linolenic acid feeding, indicating rapid metabolism to longer chain omega-6 fatty acids. These results show that oral feeding of gamma-linolenic acid-rich plant lipid markedly affects the disease course of acute EAE and CREAE and is associated with an increase in cell membrane long chain omega-6 fatty acids, production of PGE2 and gene transcription and, on activation, secretion of TGF-?1.

Harbige, L S; Layward, L; Morris-Downes, M M; Dumonde, D C; Amor, S

2000-01-01

345

The protective effects of omega-6 fatty acids in experimental autoimmune encephalomyelitis (EAE) in relation to transforming growth factor-beta 1 (TGF-beta1) up-regulation and increased prostaglandin E2 (PGE2) production.  

PubMed

Polyunsaturated fatty acids are known to affect the immune response and administration of the omega-6 fatty acid linoleic acid has been reported to be beneficial in multiple sclerosis (MS) and EAE. In this study we have investigated the effects of oral feeding of plant lipid rich in the omega-6 fatty acid gamma-linolenic acid from Borago officinalis on acute and relapse disease and the immune response in EAE using SJL mice. EAE was induced by an encephalitogenic peptide (92-106) of myelin oligodendrocyte glycoprotein (MOG), and mice were fed the plant lipid daily from 7 days after EAE induction to assess the effects on acute disease and from day 25 to assess the effects on disease relapse. The clinical incidence and histological manifestations of acute EAE, and the clinical relapse phase of chronic relapsing EAE (CREAE) were markedly inhibited by omega-6 fatty acid feeding. A significant increase in the production of TGF-beta1 in response to concanavalin A (Con A) at day 13 and a significant increase in TGF-beta1 and PGE2 to Con A, PPD and MOG peptide (92-106) at day 21 were detected in spleen mononuclear cells from fatty acid-fed mice. There was no difference in interferon-gamma, IL-4 and IL-2 production between the fatty acid-fed and control groups. Significantly higher TGF-beta mRNA expression was found in the spleens of omega-6 fatty acid-fed mice at day 21. There were no differences in spleen cell proliferative response to Con A, PPD and MOG peptide (92-106). Biochemical analysis of spleen cell membrane fatty acids revealed significant increases in the eicosanoid precursor fatty acids dihomo-gamma-linolenic acid and arachidonic acid in response to gamma-linolenic acid feeding, indicating rapid metabolism to longer chain omega-6 fatty acids. These results show that oral feeding of gamma-linolenic acid-rich plant lipid markedly affects the disease course of acute EAE and CREAE and is associated with an increase in cell membrane long chain omega-6 fatty acids, production of PGE2 and gene transcription and, on activation, secretion of TGF-beta1. PMID:11122253

Harbige, L S; Layward, L; Morris-Downes, M M; Dumonde, D C; Amor, S

2000-12-01

346

Method for production of petroselinic acid and OMEGA12 hexadecanoic acid in transgenic plants  

DOEpatents

The present invention relates to a process for producing lipids containing the fatty acid, petroselinic acid, in plants. The production of petroselinic acid is accomplished by genetically transforming plants which do not normally accumulate petroselinic acid with a gene for a {omega}12 desaturase from another species which does normally accumulate petroselinic acid. 19 figs.

Ohlrogge, J.B.; Cahoon, E.B.; Shanklin, J.; Somerville, C.R.

1995-07-04

347

Method for production of petroselinic acid and OMEGA12 hexadecanoic acid in transgenic plants  

DOEpatents

The present invention relates to a process for producing lipids containing the fatty acid petroselinic acid in plants. The production of petroselinic acid is accomplished by genetically transforming plants which do not normally accumulate petroselinic acid with a gene for a .omega.12 desaturase from another species which does normally accumulate petroselinic acid.

Ohlrogge, John B. (Okemos, MI); Cahoon, Edgar B. (Lansing, MI); Shanklin, John (Upton, NY); Somerville, Christopher R. (Okemos, MI)

1995-01-01

348

Analysis and transformation of image using spectral transformation technique  

Microsoft Academic Search

Image processing is a rapidly growing field. There are several transforms that do image transformation i.e image enhancement and segmentation. Among all the transformations spectral transformation is the simplest one because it is similar to the commonly used geometric coordinate transformation except that the geometric coordinate are replaced with the spectral bands. I can perform spectral transformation by different algorithms,

V. Singh; M. Singh

2010-01-01

349

A Catalan Transform and Related Transformations on Integer Sequences  

NASA Astrophysics Data System (ADS)

We introduce and study an invertible transformation on integer sequences related to the Catalan numbers. Transformation pairs are identified among classical sequences. A closely related transformation which we call the generalized Ballot transform is also studied, along with associated transformations. Results concerning the Fibonacci, Jacobsthal and Pell numbers are derived. Finally, we derive results about combined transformations.

Barry, Paul

2005-09-01

350

A protocol for transformation of Torenia.  

PubMed

This chapter describes an Agrobacterium tumefaciens-mediated transformation protocol for torenia, a plant that has several useful characteristics and is primarily used for ornamental and experimental purposes. Leaf segments of torenia were co-cultured with A. tumefaciens containing a vector plasmid for 7 days at 22°C under dark conditions on Murashige and Skoog (MS) medium containing 1 mg/L benzyladenine, 1 mg/L indoleacetic acid, and 100 ?M acetosyringone. Subsequent culturing at 25°C under a 16-h photoperiod with fluorescent light on MS medium containing 1 mg/L benzyladenine, 300 mg/L carbenicillin, and selection agent (300 mg/L kanamycin or 20 mg/L hygromycin) allowed for transformant selection. Transgenic shoots were obtained from green compact calli after 2-3 months of culture in the selection medium. This method can achieve a transformation rate of approximately 5% (transformants/explant). PMID:22351016

Aida, Ryutaro

2012-01-01

351

Gas-phase Acidities of Aspartic Acid, Glutamic Acid, and their Amino Acid Amides.  

SciTech Connect

Gas-phase acidities (GA or ?Gacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkage’s importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 3–4 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2? group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

Li, Zhong; Matus, Myrna H.; Velazquez, Hector A.; Dixon, David A.; Cassady, Carolyn J.

2007-02-14

352

Gas-phase acidities of aspartic acid, glutamic acid, and their amino acid amides  

NASA Astrophysics Data System (ADS)

Gas-phase acidities (GA or [Delta]Gacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkage's importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 3-4 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2- group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

Li, Zhong; Matus, Myrna H.; Velazquez, Hector Adam; Dixon, David A.; Cassady, Carolyn J.

2007-09-01

353

The LMT Transformational System  

Microsoft Academic Search

We present a newly designed transformational system for the MT system LMT, consisting of a transformational formalism, LMT-TL,\\u000a and an algorithm for applying transformations written in this formalism. LMT-TL is both expressive and simple because of the\\u000a systematic use of a powerful pattern matching mechanism that focuses on dependency trees. LMT-TL is a language in its own\\u000a right, with no

Michael C. Mccord; Arendse Bernth

1998-01-01

354

The Cascaded Hough Transform  

Microsoft Academic Search

When using the original slope-intercept parameterisationfor the Hough transform, the resulting parameterspace actually corresponds to the dual space. Indeed,lines are transformed into points, and for everypoint there is also a corresponding line. This paperpresents a way of exploiting this special property, bythe introduction of the Cascaded Hough Transform, orCHT for short. This allows to look for the overallstructure in an

Tinne Tuytelaars; Marc Proesmans; Luc Van Gool

1998-01-01

355

Nanosecond Pulse Transformers  

Microsoft Academic Search

The transmission-line approach to the design of transformers yields a unit with no first-order rise-time limit since this approach uses distributed rather than lumped constants. The total time delay through the transmission-line-type transformer may exceed the rise time by a large factor, unlike conventional transformers. The extra winding length can be employed to improve the low-frequency response of the unit.

C. Norman Winningstad

1959-01-01

356

Magnetically Controlled Variable Transformer  

NASA Technical Reports Server (NTRS)

Improved variable-transformer circuit, output voltage and current of which controlled by use of relatively small current supplied at relatively low power to control windings on its magnetic cores. Transformer circuits of this type called "magnetic amplifiers" because ratio between controlled output power and power driving control current of such circuit large. This ratio - power gain - can be as large as 100 in present circuit. Variable-transformer circuit offers advantages of efficiency, safety, and controllability over some prior variable-transformer circuits.

Kleiner, Charles T.

1994-01-01

357

Two Different Squeeze Transformations  

NASA Technical Reports Server (NTRS)

Lorentz boosts are squeeze transformations. While these transformations are similar to those in squeezed states of light, they are fundamentally different from both physical and mathematical points of view. The difference is illustrated in terms of two coupled harmonic oscillators, and in terms of the covariant harmonic oscillator formalism.

Han, D. (Editor); Kim, Y. S.

1996-01-01

358

Pathways to Transformation.  

ERIC Educational Resources Information Center

The ubiquitous use of the term "transformation" in experiential education has blurred its specific meaning in any given case. Designing an effective curriculum requires instructors to determine what kind of transformation they would like to generate. A review of two research projects provides insights about different types of personal change and…

Henderson, Bob; Cushing, Pamela

359

Direct current transformer  

NASA Technical Reports Server (NTRS)

A direct current transformer in which the primary consists of an elongated strip of superconductive material, across the ends of which is direct current potential is described. Parallel and closely spaced to the primary is positioned a transformer secondary consisting of a thin strip of magnetoresistive material.

Khanna, S. M.; Urban, E. W. (inventors)

1979-01-01

360

Operating Transformers by Temperature  

Microsoft Academic Search

This paper discusses a proposal, sponsored by the Transformer Subcommittee of the Committee on Electrical Machinery, which is intended to serve as a guide in operating transformers by temperature rather than in accordance with their nameplate ratings. There is a real difference between ``rating standards'' and ``recommendations for operation;'' one simply specifies the measure of a machine under a definite

W. M. Dann

1930-01-01

361

Human Dimension of Transformation.  

National Technical Information Service (NTIS)

The transformation of the U.S. military and the Department of Defense represents a complex process which has been evolving since the end of the Cold War. Successful transformation will require a cultural change that focuses on producing forces that when i...

R. E. Scurlock

2004-01-01

362

TRANSFORMS, ALGORITHMS AND APPLICATIONS  

Microsoft Academic Search

Fourier transforms and other related transforms are an essential tool in applications of science, engineering and technology. In fact, much of the work currently being done in mathematics, physics and engineering has its roots in Fourier's pioneering idea of representing an arbitrary function as the sum of a trigonometric series. The main purpose of these notes is to give a

M. J. Soares

363

The Discrete Pulse Transform  

Microsoft Academic Search

We investigate a recent algorithm, here called a discrete pulse transform (DPT), for the multiresolution analysis of a sequence. A DPT represents a sequence as a sum of pulses, where a pulse is a sequence which is zero everywhere except for a certain number of consecutive elements which have a constant nonzero value. Unlike the discrete Fourier and wavelet transforms,

C. H. Rohwer; D. P. Laurie

2006-01-01

364

Transformational Plasmon Optics  

Microsoft Academic Search

Transformation optics has recently attracted extensive interest, since it provides a novel design methodology for manipulating light at will. Although transformation optics in principle embraces all forms of electromagnetic phenomena on all length scales, so far, much less efforts have been devoted to near-field optical waves, such as surface plasmon polaritons (SPPs). Due to the tight confinement and strong field

Yongmin Liu; Thomas Zentgraf; Guy Bartal; Xiang Zhang

2010-01-01

365

Biochemical transformation of coals  

DOEpatents

A method of biochemically transforming macromolecular compounds found in solid carbonaceous materials, such as coal is provided. The preparation of new microorganisms, metabolically weaned through challenge growth processes to biochemically transform solid carbonaceous materials at extreme temperatures, pressures, pH, salt and toxic metal concentrations is also disclosed. 7 figs.

Lin, M.S.; Premuzic, E.T.

1999-03-23

366

Support Principals, Transform Schools  

ERIC Educational Resources Information Center

The Transformational Coaching Team in Oakland Unified School District provides differentiated, sustained, job-embedded support to the district's school leaders. In this article, members of the team describe how they work with principals to transform the culture of schools. Student achievement data show above-average improvement in schools in which…

Aguilar, Elena; Goldwasser, Davina; Tank-Crestetto, Kristina

2011-01-01

367

Genetic Transformation of Bacteria.  

ERIC Educational Resources Information Center

An activity in which students transform an ampicillin-sensitive strain of E. coli with a plasmid containing a gene for ampicillin resistance is described. The procedure for the preparation of competent cells and the transformation of competent E. coli is provided. (KR)

Moss, Robert.

1991-01-01

368

Transformational Development of User Interfaces with Graph Transformations  

Microsoft Academic Search

In software engineering transformational development aims at developing software systems by transforming a coarse-grained specification to final code (or to a detailed specification) through a sequence of small transformation steps. Transformational development is known to bring benefits such as: correctness-preserving of the development cycle, explicit mappings between development steps, reusability and reversibility of transformations. No piece of literature provides a

Quentin Limbourg; Jean Vanderdonckt

2004-01-01

369

The martensitic transformation in ceramics — its role in transformation toughening  

Microsoft Academic Search

This paper reviews the current knowledge and understanding of martensitic transformations in ceramics — the tetragonal to monoclinic transformation in zirconia in particular. This martensitic transformation is the key to transformation toughening in zirconia ceramics. A very considerable body of experimental data on the characteristics of this transformation is now available. In addition, theoretical predictions can be made using the phenomenological

Patrick M. Kelly; L. R. Francis Rose

2002-01-01

370

[Agrobacterium rhizogenes-mediated transformation and the regeneration of transformants in Alhagi pseudalhagi].  

PubMed

The regenerated shoot segments of Alhagi pseudalhagi were sliced and infected with Agrobacterium rhizogenes strain A4. The hairy roots and transformed calli were obtained through selection on hormone free MS medium. The transformants were cultured on MS medium with 2 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D) and 0.5-1 mg/L 6-benzylaminopurine (6-BA) to induce calli. 3 mg/L 6-BA and 0.5 mg/L naphthalene acetic acid (NAA) were applied for shoot differentiation. Shoots were planted on MS medium with 2 mg/L indole-3-butyric acid (IBA) and produced roots. Opine analysis proved the integration and expression of T-DNA in over 95% hairy roots, 75% transformed calli and transformed plantlets respectively. The 81% hairy root cells had normal chromosome numbers (2n = 18). The alterations of chromosome number were observed. After one year of subculturing, the regeneration ability of transformants was maintained. PMID:12549099

Bu, H Y; Jing, J Z; Jia, J F

2001-06-01

371

The Practice of Transformative Pedagogy  

ERIC Educational Resources Information Center

The author examined the practice of transformative pedagogy in an undergraduate teacher education program. The research was guided by two questions: What is the impact of transformative pedagogy on fostering preservice teachers' transformative learning? and What practices of transformative pedagogy impact student transformative learning?…

Ukpokodu, Omiunota

2009-01-01

372

Transformer design tradeoffs  

NASA Technical Reports Server (NTRS)

Material was presented to assist transformer designers in the transition from long-used English units to the less familiar metric equivalents. A coordination between the area product numbers ap (product of window and core cross-section areas) and current density J was developed for a given regulation and temperature rise. Straight-line relationships for Ap and Volume, Ap and surface area At and, Ap and weight were developed. These relationships can now be used as new tools to simplify and standardize the process of transformer design. They also made it possible to design transformers of small bulk and volume or to optimize efficiency.

Mclyman, W. T.

1976-01-01

373

Pattern Transformation with DNA Circuits  

PubMed Central

Readily programmable chemical networks are important tools as the scope of chemistry expands from individual molecules to larger molecular systems. While many complex systems have been constructed using conventional organic and inorganic chemistry, the programmability of biological molecules such as nucleic acids allows for precise, high-throughput, and automated design, as well as simple, rapid, and robust implementation. Here we show that systematic and quantitative control over the diffusivity and reactivity of DNA molecules yields highly programmable chemical reaction networks (CRNs) that execute at the macroscale. In particular, we design and implement non-enzymatic DNA circuits capable of performing pattern transformation algorithms such as edge detection. We also show that it is possible to fine-tune and multiplex such circuits. We believe these strategies will provide programmable platforms for prototyping CRNs, for discovering bottom-up construction principles, and for generating patterns in materials.

Chirieleison, Steven M.; Allen, Peter B.; Simpson, Zack B.; Ellington, Andrew D.; Chen, Xi

2014-01-01

374

Fourier Transform Interferometry.  

National Technical Information Service (NTIS)

The basic Michelson interferometer, as used for Fourier transform spectroscopy, is analyzed in this report. The principles of operation are explained, and its inherent limitations are shown. An original analysis of apodization, for the case of an off-axis...

D. R. Hearn

1999-01-01

375

Proof in Transformation Geometry  

ERIC Educational Resources Information Center

The first of three articles showing how inductively-obtained results in transformation geometry may be organized into a deductive system. This article discusses two approaches to enlargement (dilatation), one using coordinates and the other using synthetic methods. (MM)

Bell, A. W.

1971-01-01

376

A Classical Science Transformed.  

ERIC Educational Resources Information Center

Describes how satellites and other tools of space technology have transformed classical geodesy into the science of space geodynamics. The establishment and the activities of the French Center for Geodynamic and Astronomical Research Studies (CERGA) are also included. (HM)

Kovalevsky, Jean

1979-01-01

377

Pulse Transformer Design Study.  

National Technical Information Service (NTIS)

The design of a compact, lightweight, high average power, air-core pulse transformer to satisfy the electrical and physical requirements of a developmental power conditioning system is presented. (Author)

H. Aslin P. Chao

1975-01-01

378

The Laguerre Transform.  

National Technical Information Service (NTIS)

A novel transform is presented which maps continuum functions (such as probability distributions) into discrete sequences and permits rapid numerical calculation of convolutions, multiple convolutions, and Neumann expansions for Volterra integral equation...

J. Keilson W. Nunn U. Sumita

1980-01-01

379

Transformational Grammars Again.  

National Technical Information Service (NTIS)

The note presents some criticisms of Chomsky's theory of Transformational Grammar, and in particular of his most recent attempt to demarcate syntax from semantics by means of the distinction between selectional and subcategorization rules. I argue that, a...

Y. Wilks

1967-01-01

380

Generic quantum Fourier transforms  

Microsoft Academic Search

The quantum Fourier transform (QFT) is the principal ingredient of most efficient quantum algorithms. We present a generic framework for the construction of efficient quantum circuits for the QFT by \\

Cristopher Moore; Daniel N. Rockmore; Alexander Russell

2004-01-01

381

Fiber optics transforms  

Microsoft Academic Search

We give fiber or planar lightwave circuit (PLC) architectures to implement the discrete Fourier transform (DFT) and the discrete Hartley transform (DHT) directly in the optical domain. In both cases, we present a recursive approach for the decimation-in-frequency algorithm, considering parallel and serial input configurations. We also describe PLC devices for high-speed optical filtering and data compression, based on discrete

Michela Svaluto Moreolo; Gabriella Cincotti

2008-01-01

382

Plant transformation technology  

Microsoft Academic Search

Plant transformation has its roots in the research on Agrobacterium that was being undertaken in the early 1980s. The last two decades have seen significant developments in plant transformation\\u000a technology, such that a large number of transgenic crop plants have now been released for commercial production. Advances\\u000a in the technology have been due to development of a range of Agrobacterium-mediated

Christine A. Newell

2000-01-01

383

Series Transmission Line Transformer  

DOEpatents

A series transmission line transformer is set forth which includes two or more of impedance matched sets of at least two transmissions lines such as shielded cables, connected in parallel at one end ans series at the other in a cascading fashion. The cables are wound about a magnetic core. The series transmission line transformer (STLT) which can provide for higher impedance ratios and bandwidths, which is scalable, and which is of simpler design and construction.

Buckles, Robert A. (Livermore, CA); Booth, Rex (Livermore, CA); Yen, Boris T. (El Cerrito, CA)

2004-06-29

384

The application of Fourier-transform infrared (FTIR) and Raman spectroscopy (FTR) to the evaluation of structural changes in wool fibre keratin after deuterium exchange and modification by the orthosilicic acid  

NASA Astrophysics Data System (ADS)

An injury of hair macrostructure and substantial alkalinity of the water-lipid shield medium on wool fibre surface is conducive to a transition of heavy metal elements into ion forms. It also helps SiO 2 in a transition into a colloidal form of orthosilicic acid and its penetration in this form of the wool fibre structure. Consequently, it leads to the biomineralization of the wool fibre [J. Mol. Struct. 511-512 (1999) 307; J. Mol. Struct. 511-512 (2000) 397]. Changes taking place in the process of biomineralization, mainly in the amorphous region, may be responsible for the effectiveness of the technological processes and the properties of ready wool products [3]. Wool fibres obtained from Polish Merino sheep were treated with solution of orthosilicic acid (H 4SiO 4· nH 2O) in experimental conditions during which fibres first underwent extraction with methylene chloride and them with asolution of orthosilicic acid in alkaline medium. Studies of deuterium exchange in the wool fibre keratin were applied to study changes in the structure of wool fibre keratin in the process of orthosilicic acid treatment. The changes in the structure of wool fibre were studied by means of infrared spectroscopy (FTIR) and Raman spectroscopy (FTR).

Wojciechowska, El?bieta; W?ochowicz, Andrzej; Wysocki, Marian; Pielesz, Anna; Wese?ucha-Birczy?ska, Aleksandra

2002-09-01

385

Transformation of phenol into phenylalanine by a methanogenic consortium  

SciTech Connect

Phenol is a widely used chemical found in many wastewaters of industrial origin. The degradation of phenol by methanogenic bacterial consortia has been reported by many investigators. To better characterise the metabolism of this consortium, a new metabolic pathway of benzoic acid, an intermediary in the degradation of phenol, is reported. This study describes the transformations of benzoic acid into 3-phenylpropionic acid and phenylalanine. 25 refs., 5 figs.

Lepine, F.; Milot, S.; Beaudet, R.; Villemur, R. [Universite du Quebec, Laval (Canada)] [and others

1996-03-01

386

Transformation superplasticity of zirconium  

SciTech Connect

A tensile strain of 270% was achieved for coarse-grained zirconium subjected to transformation superplasticity condition, where strain increments are accumulated upon repeated thermal cycling around the allotropic transformation temperature under the biasing effect of a uniaxial tensile stress. The strain increment per cycle was found to consist of two equal contributions from transformations on heating and cooling and to increase linearly with the applied stress. The measured strain increments are in good quantitative agreement with predictions based on the average internal stress during the transformation, which was determined independently from experimental transformation times. As the cycling frequency is raised, the average strain rate increases (a maximum value of 1.3 {times} 10{sup {minus}4} s{sup {minus}1} was measured), but the strain increment per cycle decreases above a critical cycling frequency, for which the sample gage section undergoes only a partial phase transformation. The resulting reduction in internal mismatch and increase in internal stress are modeled using the experimental observation that {beta}-Zr deforms by a mixture of diffusional and dislocation creep in the stress range of interest.

Zwigl, P. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering; Dunand, D.C. [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering

1998-10-01

387

Floral Transformation of Wheat  

NASA Astrophysics Data System (ADS)

A method is described for the floral transformation of wheat using a protocol similar to the floral dip of Arabidopsis. This method does not employ tissue culture of dissected embryos, but instead pre-anthesis spikes with clipped florets at the early, mid to late uninucleate microspore stage are dipped in Agrobacterium infiltration media harboring a vector carrying anthocyanin reporters and the NPTII selectable marker. T1 seeds are examined for color changes induced in the embryo by the anthocyanin reporters. Putatively transformed seeds are germinated and the seedlings are screened for the presence of the NPTII gene based on resistance to paromomycin spray and assayed with NPTII ELISAs. Genomic DNA of putative transformants is digested and analyzed on Southern blots for copy number to determine whether the T-DNA has integrated into the nucleus and to show the number of insertions. The non-optimized transformation efficiencies range from 0.3 to 0.6% (number of transformants/number of florets dipped) but the efficiencies are higher in terms of the number of transformants produced/number of seeds set ranging from 0.9 to 10%. Research is underway to maximize seed set and optimize the protocol by testing different Agrobacterium strains, visual reporters, vectors, and surfactants.

Agarwal, Sujata; Loar, Star; Steber, Camille; Zale, Janice

388

Kinetics of phase transformations  

SciTech Connect

This volume contains papers presented at the Materials Research Society symposium on Kinetics of Phase Transformations held in Boston, Massachusetts from November 26-29, 1990. The symposium provided a forum for research results in an exceptionally broad and interdisciplinary field. Presentations covered nearly every major class of transformations including solid-solid, liquid-solid, transport phenomena and kinetics modeling. Papers involving amorphous Si, a dominant topic at the symposium, are collected in the first section followed by sections on four major areas of transformation kinetics. The symposium opened with joint sessions on ion and electron beam induced transformations in conjunction with the Surface Chemistry and Beam-Solid Interactions: symposium. Subsequent sessions focused on the areas of ordering and nonlinear diffusion kinetics, solid state reactions and amorphization, kinetics and defects of amorphous silicon, and kinetics of melting and solidification. Seven internationally recognized invited speakers reviewed many of the important problems and recent results in these areas, including defects in amorphous Si, crystal to glass transformations, ordering kinetics, solid-state amorphization, computer modeling, and liquid/solid transformations.

Thompson, M.O. (Cornell Univ., Ithaca, NY (United States)); Aziz, M.J. (Harvard Univ., Cambridge, MA (United States)); Stephenson, G.B. (International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center)

1992-01-01

389

Decreased DNA damage by acid and increased repair of acid-damaged DNA in acid-habituated Escherichia coli.  

PubMed

A study of the conjugal transfer of ColV,I-K94 tn 10 from acid-treated donors suggested that acid-habituated recipients repair acid-damaged plasmid DNA better than those that are not habituated. The presence of an increased repair activity for acid-damaged DNA in habituated cells was confirmed by isolating pBR322 from acid-treated organisms; habituated cells produced more transformants when transformed by it than did non-habituated ones. Additionally, agarose gel electrophoretic studies of pBR322 DNA isolated from acid-damaged cells and tests of its transforming activity both indicated that plasmid DNA in habituated cells is less damaged by extreme acidity than is that in non-habituated organisms. PMID:1938675

Raja, N; Goodson, M; Smith, D G; Rowbury, R J

1991-06-01

390

Precise Semantics of EMF Model Transformations by Graph Transformation  

Microsoft Academic Search

Model transformation is one of the key activities in model-driven soft- ware development. An increasingly popular technology to define modeling lan- guages is provided by the Eclipse Modeling Framework (EMF). Several EMF model transformation approaches have been developed, focusing on different transformation aspects. To validate model transformations wrt. functional behav- ior and correctness, a formal foundation is needed. In this

Enrico Biermann; Claudia Ermel; Gabriele Taentzer

2008-01-01

391

Transformation Assay for Identification of Psychrotrophic Achromobacters  

PubMed Central

The finding that many psychrotrophic, gram-negative, nonmotile, oxidase-positive coccobacilli (achromobacters) are competent for genetic transformation made possible the development of a transformation assay that permits recognition of genetically related strains. It has been demonstrated that 109 independently isolated achromobacters are genetically related since deoxyribonucleic acid samples from all of these organisms were able to transform a single competent auxotrophic strain to prototrophy. Genetically interacting bacteria included strains that lacked one or more of the characteristics typical for most achromobacters. An oxidase-negative mutant of one of these strains reacted positively in the transformation assay, unlike other oxidase-negative bacteria. Achromobacters were derived from fish, poultry, irradiated foods, seawater, and other sources. One strain previously classified as Micrococcus cryophilus has been shown to be related to the achromobacters. Two achromobacters had an optimum growth temperature of 35°C and behaved as typical mesophiles. The moraxellae and Acinetobacter were shown to be unrelated to the achromobacters by using the transformation assay. The ready demonstration of genetic relatedness provides a new basis for taxonomic grouping of the psychrotrophic achromobacters. Images

Juni, Elliot; Heym, Gloria A.

1980-01-01

392

Transformation of Anaplasma phagocytophilum  

PubMed Central

Background Tick-borne pathogens cause emerging zoonoses, and include fastidious organisms such as Anaplasma phagocytophilum. Because of their obligate intracellular nature, methods for mutagenesis and transformation have not been available. Results To facilitate genetic manipulation, we transformed A. phagocytophilum (Ap) to express a green fluorescent protein (GFP) with the Himar1 transposase system and selection with the clinically irrelevant antibiotic spectinomycin. Conclusion These transformed bacteria (GFP/Ap) grow at normal rates and are brightly fluorescent in human, monkey, and tick cell culture. Molecular characterization of the GFP/Ap genomic DNA confirmed transposition and the flanking genomic insertion locations were sequenced. Three mice inoculated with GFP/Ap by intraperitoneal injection became infected as demonstrated by the appearance of morulae in a peripheral blood neutrophil and re-isolation of the bacteria in culture.

Felsheim, Roderick F; Herron, Michael J; Nelson, Curtis M; Burkhardt, Nicole Y; Barbet, Anthony F; Kurtti, Timothy J; Munderloh, Ulrike G

2006-01-01

393

Shape transformation for polyhedral objects  

Microsoft Academic Search

Techniques that transform one two-dimensionaf image into another have gained widespread use m recent yeara. Extending these tech- niques to transform pairs of 3D objects, as opposed to 2D images of the objects, providea several advsntagea, including the ability to sn- imate the objects independently of the transformation. This paper presents an algorithm for computing such transformations. The al- gorithm

James R. Kent; Wayne E. Carlson; Richard E. Parent

1992-01-01

394

Stationary Hadamard Transform Spectrometry.  

NASA Astrophysics Data System (ADS)

Two novel applications of a stationary electro -optic shutter have been successfully developed for use in Hadamard transform spectrometry. The first of these combines interferometric and Hadamard transform techniques for a spectrometric instrument offering advantages over conventional spectrometers. A Hadamard transform encoding mask is incorporated into a multiple-beam Fizeau interferometer design, allowing the use of a single detector element rather than the more problematic linear detector arrays in the near-infrared region. The instrument can be made small, inexpensive, and compatible with harsh industrial environments. The second application of the stationary encoding mask is in conjunction with a Hadamard transform (HT) Raman spectrometer for use in the near-infrared spectral region. This spectral region is important to the practicing Raman spectroscopist since problems associated with fluorescence in the visible spectral region are reduced significantly. However, on going to the near-infrared region, a sacrifice is made in terms of adequate Raman signal resulting in poorer signal -to-noise ratio. As such, there is a need for multiplexing spectrometers to recover the loss associated with the near -infrared spectral region. The Hadamard transform Raman spectrometer using a stationary encoding mask offers this multiplex advantage. Both instruments share some special features such as the ability to perform spectral subtraction. However, the stationary encoding masks used in both instruments have some disadvantages (e.g. less than 100% modulation efficiency). One disadvantage associated with the electro -optic encoding masks is the finite mask response time. The finite mask response time, in addition to increasing data acquisition time, has deleterious effects on the recovered spectrum following a Hadamard transform To a large extent, the problem has been alleviated by a special correction procedure which when applied to spectral results actually compensates for the spectral error associated with the finite mask response time. The use of this correction procedure, in effect, allows the user to acquire spectral data at accelerated rates relative to conventional acquisition schemes.

Tate, James David

395

Toothpicks and Transformations  

NSDL National Science Digital Library

In this math lesson, learners explore transformations and quadratic functions through toothpick patterns. Learners examine the mathematical pattern that emerges as they build a geometric design with toothpicks. The pattern is quadratic, and the learners determine the mathematical model in several different forms. Learners investigate the recursive nature of the relationship. An explicit model for the relation is developed, and a third model is developed by examining the scatterplot and determining the equation from the transformations. Finally, the group uses graphing calculators to develop another model and to verify that all of the models--factored form, vertex form, and general form--are equivalent.

Pbs

2012-01-01

396

Evolved image compression transforms  

NASA Astrophysics Data System (ADS)

State-of-the-art image compression and reconstruction schemes utilize wavelets. Quantization and thresholding are commonly used to achieve additional compression, but cause permanent, irreversible information loss. This paper describes an investigation into whether evolutionary computation (EC) may be used to optimize forward (compression-only) transforms capable of matching or exceeding the compression capabilities of a selected wavelet, while reducing the aggregate error in images subsequently reconstructed by that wavelet. Transforms are independently trained and tested using three sets of images: digital photographs, fingerprints, and satellite images.

Aldridge, Shawn; Babb, Brendan; Moore, Frank; Peterson, Michael

2010-04-01

397

Boswellic acid inhibits expression of acid sphingomyelinase in intestinal cells  

PubMed Central

Background Boswellic acid is a type of triterpenoids with antiinflammatory and antiproliferative properties. Sphingomyelin metabolism generates multiple lipid signals affecting cell proliferation, inflammation, and apoptosis. Upregulation of acid sphingomyelinase (SMase) has been found in several inflammation-related diseases such as inflammatory bowel diseases, atherosclerosis, and diabetes. Methods The present study is to examine the effect of 3-acetyl-11-keto-?-boswellic acids (AKBA), a potent boswellic acid, on acid SMase activity and expression in intestinal cells. Both transformed Caco-2 cells and non-transformed Int407 cells were incubated with AKBA. After incubation, the change of acid SMase activity was assayed biochemically, the enzyme protein was examined by Western blot, and acid SMase mRNA was quantified by qPCR. Results We found that AKBA decreased acid SMase activity in both intestinal cell lines in dose and time dependent manners without affecting the secretion of the enzyme to the cell culture medium. The effect of AKBA was more effective in the fetal bovine serum-free culture medium. Among different types of boswellic acid, AKBA was the most potent one. The inhibitory effect on acid SMase activity occurred only in the intact cells but not in cell-free extract in the test tubes. At low concentration, AKBA only decreased the acid SMase activity but not the quantity of the enzyme protein. However, at high concentration, AKBA decreased both the mass of acid SMase protein and the mRNA levels of acid SMase in the cells, as demonstrated by Western blot and qPCR, respectively. Under the concentrations decreasing acid SMase activity, AKBA significantly inhibited cell proliferation. Conclusion We identified a novel inhibitory effect of boswellic acids on acid SMase expression, which may have implications in human diseases and health.

2009-01-01

398

The general quadratic Radon transform  

NASA Astrophysics Data System (ADS)

The general quadratic Radon transform in two dimensions is investigated. Whereas the classical Radon transform of a smooth function represents the integration over all lines, the general quadratic Radon transform integrates over all conic sections. First, the parabolic isofocal Radon transform, i.e. the restriction of the general quadratic Radon transform to all parabolae with focus in the origin, is defined and illustrated. We show its intense relation to the classical Radon transform, deduce a support theorem, formulate an extension of the support theorem and derive an inversion formula. The natural extension to a more general class of isofocal quadratic Radon transforms is outlined. We show how the general quadratic Radon transform can be derived from the integrals over all parabolae by solving the related Cauchy problem. Finally, we introduce an entirely geometrical definition of a generalized Radon transform, the oriented generalized Radon transform.

Denecker, Koen; Van Overloop, Jeroen; Sommen, Frank

1998-06-01

399

Some transformations of tacrolimus, an immunosuppressive drug.  

PubMed

Transformations of the macrocyclic lactone tacrolimus (1), an important immunosuppressive drug produced by Streptomyces species, are described. These transformation products are primarily of interest as reference substances for drug impurity analyses. Upon action of acid (p-toluenesulfonic acid in toluene), tacrolimus is dehydrated by loss of water from the ?-hydroxyketone moiety with partial inversion of configuration at C-8, resulting in formation of 5-deoxy-?(5,6)-tacrolimus and 5-deoxy-?(5,6)-8-epitacrolimus. The structure of the latter was determined by single-crystal X-ray crystallography. The same products are formed upon action of free radicals (iodine in boiling toluene), along with formation of 8-epitacrolimus. The latter is converted by p-toluenesulfonic acid to 5-deoxy-?(5,6)-8-epitacrolimus. Treatment of tacrolimus with weak base (1,5-diazabicyclo[4.3.0]nonene) gives, in addition to 8-epitacrolimus, the open-chain acid corresponding to 5-deoxy-?(5,6)-tacrolimus, a rare non-cyclic derivative of tacrolimus. Strong base (t-butoxide) causes pronounced degradation of the molecule. Thermolysis of tacrolimus leads to ring expansion by an apparent [3,3]-sigmatropic rearrangement of the allylic ester moiety with subsequent loss of water from the ?-hydroxyketone moiety. (1)H and (13)C NMR spectra of the obtained compounds, complicated by the presence of amide bond rotamers and ketal moiety tautomers, were assigned by extensive use of 2D NMR techniques. PMID:23238171

Skytte, Dorthe M; Jaroszewski, Jerzy W; Johansen, Kenneth T; Hansen, Steen Honoré; Hansen, Liselotte; Nielsen, Peter G; Frydenvang, Karla

2012-12-10

400

Prioritization of pesticide environmental transformation products in drinking water supplies.  

PubMed

Receiving waters within catchments may be exposed to many different transformation products following the application of pesticides. As environmental waters are abstracted for drinking water treatment these compounds may pose a risk to human health. This paper describes a prioritization approach for identifying the most important transformation products in drinking water sources. The approach can be applied to different geographical areas that have suitable pesticide usage data. The risk based approach incorporates data on pesticide usage and toxicity as well as transformation product formation, mobility, and persistence. The application of the approach is illustrated for two geographical areas that have good quality pesticide usage data: Great Britain and California. The transformation products with the highest risk index and a complete experimentally derived data set for Great Britain were 3,5,6-trichloro-2-pyridinol, thifensulfuron acid, and kresoxim-methyl acid and for California were carbendazim, aldicarb sulfoxide, and RP30228. PMID:17180979

Sinclair, Chris J; Boxall, Alistair B A; Parsons, Simon A; Thomas, Miles R

2006-12-01

401

Comparative study of Hilbert–Huang transform, Fourier transform and wavelet transform in pavement profile analysis  

Microsoft Academic Search

This study employs the Hilbert–Huang transform (HHT), the wavelet transform and the Fourier transform to analyse the road surface profiles of three pavement profiles. The wavelet and Fourier transforms have been the traditional spectral analysis methods, but they are predicated on a priori selection of basis functions that are either of infinite length or have fixed finite widths. The central

A. Y. Ayenu-Prah; N. O. Attoh-Okine

2009-01-01

402

Production of conjugated fatty acids by lactic acid bacteria.  

PubMed

Conjugated fatty acids have attracted much attention as a novel type of biologically beneficial functional lipid. Some isomers of conjugated linoleic acid (CLA) reduce carcinogenesis, atherosclerosis, and body fat. Considering the use of CLA for medicinal and nutraceutical purposes, a safe isomer-selective process is required. The introduction of biological reactions for CLA production could be an answer. We screened microbial reactions useful for CLA production, and found several unique reactions in lactic acid bacteria. Lactic acid bacteria produced CLA from linoleic acid. The produced CLA comprised a mixture of cis-9,trans-11-octadecadienoic acid (18:2) and trans-9,trans-11-18:2. Lactobacillus plantarum AKU 1009a was selected as a potential CLA producer. Using washed cells of L. plantarum AKU 1009a as a catalyst, CLA production from linoleic acid reached 40 mg/ml under the optimized conditions. The CLA-producing reaction was found to consist of two successive reactions, i.e., hydration of linoleic acid to 10-hydroxy-12-octadecenoic acid and dehydrating isomerization of the hydroxy fatty acid to CLA. On the basis of these results, the transformation of hydroxy fatty acids by lactic acid bacteria was investigated. Lactic acid bacteria transformed ricinoleic acid (12-hydroxy-cis-9-octadecenoic acid) to CLA (a mixture of cis-9,trans-11-18:2 and trans-9,trans-11-18:2). Castor oil, which is rich in the triacylglycerol form of ricinoleic acid, was also found to act as a substrate for CLA production by lactic acid bacteria with the aid of lipase-catalyzed triacylglycerol hydrolysis. L. plantarum AKU 1009a produced conjugated trienoic fatty acids from alpha- and gamma-linolenic acid. The trienoic fatty acids produced from alpha-linolenic acid were identified as cis-9,trans-11,cis-15-octadecatrienoic acid (18:3) and trans-9,trans-11,cis-15-18:3. Those produced from gamma-linolenic were cis-6,cis-9,trans-11-18:3 and cis-6,trans-9,trans-11-18:3. The conjugated trienoic fatty acids produced from alpha- and gamma-linolenic acid were further saturated by L. plantarum AKU 1009a to trans-10,cis-15-18:2 and cis-6,trans-10-18:2, respectively. PMID:16310724

Ogawa, Jun; Kishino, Shigenobu; Ando, Akinori; Sugimoto, Satoshi; Mihara, Kousuke; Shimizu, Sakayu

2005-10-01

403

Eugenol from normal and transformed root cultures of Coluria geoides  

Microsoft Academic Search

Transformed root cultures of Coluria geoides Ledeb. were established with the use of Agrobacterium rhizogenes LBA 9402. Both normal and transformed root cultures were investigated for their growth and yield of eugenol. Normal roots were grown in B5 medium-supplemented with 0.2 mg l-1 of kinetin and 0.2 mg l-1 of 1-naphthaleneacetic acid (NAA). Hairy roots grew well in hormone-free B5

O. Olszowska; A. W. Alfermann; M. Furmanowa

1996-01-01

404

Winthrop College Transformed Curriculum.  

ERIC Educational Resources Information Center

Dealing with the issue of a changing society and recognizing that teacher education has remained basically unchanged for 100 years, the faculty of the Winthrop College School of Education agreed to take the risk involved with transforming the teacher education curriculum. Three interdisciplinary teams have identified curriculum to be taught to…

Hawisher, Margaret F.

405

Fourier Transform I  

NSDL National Science Digital Library

Created by Lang Moore for the Connected Curriculum Project, the purpose of this module is to study the Fourier transform and use it to describe solutions of the heat equation on an infinite rod. This is one of a much larger set of learning modules hosted by Duke University.

Moore, Lang

2010-07-02

406

Transforming Data into Knowledge  

ERIC Educational Resources Information Center

School systems can be data rich and information poor if they do not understand and manage their data effectively. The task for school leaders is to put existing data into a format that lends itself to answering questions and improving outcomes for the students. Common barriers to transforming data into knowledge in education settings often include…

Mills, Lane

2006-01-01

407

Transforming Education with Technology  

ERIC Educational Resources Information Center

In this EL interview, Karen Cator, the director of the Office of Educational Technology at the U.S. Department of Education, talks about ways to realize the potential of technology to transform education. She discusses what students need: their own digital devices for classroom use, the ability to use the information they access, the skills to…

Scherer, Marge

2011-01-01

408

Fourier transform deflection mapping  

Microsoft Academic Search

In a previous paper in 1992, we presented a flow visualization technique based on deflection mapping. We now present a new method for the interpretation of deflection mapping of small angles obtained by Ronchi gratings. In this method, a Fourier transform is operated on the transmission pattern of the Ronchi grating and the individual sine terms are then obtained by

Arie Dahan; Gabi Ben-Dor; Ezra Bar-Ziv

1993-01-01

409

Transformative Mixed Methods Research  

ERIC Educational Resources Information Center

Paradigms serve as metaphysical frameworks that guide researchers in the identification and clarification of their beliefs with regard to ethics, reality, knowledge, and methodology. The transformative paradigm is explained and illustrated as a framework for researchers who place a priority on social justice and the furtherance of human rights.…

Mertens, Donna M.

2010-01-01

410

Hadamard transform imaging  

Microsoft Academic Search

We have constructed a Hadamard transform Raman microscopic imaging system, and have developed it to a high definition (64K pixel) technique. We have demonstrated multispectral Raman imaging and developed the first three-dimensional (digital confocal) Raman imaging. We have explored the systematic errors in Hadamard multiplexing techniques and developed corrections. We have used our Raman microscope techniques to explore defect distributions

1992-01-01

411

Hexagonal Parallel Pattern Transformations  

Microsoft Academic Search

The concept of the two-dimensional (2-D) parallel computer with square module arrays was first introduced by Unger. It is the purpose of this paper to discuss the relative merits of square and hexagonal module arrays, to propose an operational symbolism for the various basic hexagonal modular transformations which may be performed by these comupters, to illustrate some logical circuit implementation,

M. J. E. Golay

1969-01-01

412

Leaders lost in transformation  

Microsoft Academic Search

Purpose – To examine why most Lean transformations achieve only modest favorable results, despite years of effort. Design\\/methodology\\/approach – Comparative\\/evaluative discussion of efforts made by senior managers to implement the Lean management system, with commentary on a published example. Findings – Presents common obstacles and identifies common implementation errors that must be avoided in order to realize the full benefits

M. L. Emiliani; D. J. Stec

2005-01-01

413

Fourier Transform Mass Spectrometry.  

ERIC Educational Resources Information Center

Discusses the nature of Fourier transform mass spectrometry and its unique combination of high mass resolution, high upper mass limit, and multichannel advantage. Examines its operation, capabilities and limitations, applications (ion storage, ion manipulation, ion chemistry), and future applications and developments. (JN)

Gross, Michael L.; Rempel, Don L.

1984-01-01

414

Migration by Fourier transform  

Microsoft Academic Search

Wave equation migration is known to be simpler in principle when the horizontal coordinate or coordinates are replaced by their Fourier conjugates. Two practical migration schemes utilizing this concept are developed. One scheme extends the Claerbout finite difference method, greatly reducing dispersion problems usually associated with this method at higher dips and frequencies. The second scheme effects a Fourier transform

R. H. Stolt

1978-01-01

415

Transforming Primary Mathematics  

ERIC Educational Resources Information Center

What is good mathematics teaching? What is mathematics teaching good for? Who is mathematics teaching for? These are just some of the questions addressed in "Transforming Primary Mathematics", a highly timely new resource for teachers which accessibly sets out the key theories and latest research in primary maths today. Under-pinned by findings…

Askew, Mike

2011-01-01

416

Beyond Reform: Transformation  

ERIC Educational Resources Information Center

The Coalition of Essential Schools (CES) is not a reform movement. To reform is to make a thing again; reformation implies a stasis that doesn't deliver enough for the educational future. This issue of Horace demonstrates that Essential schools and the districts and networks that support them are at various points in the journey of transformation,…

Davidson, Jill

2007-01-01

417

Leading System Transformation  

ERIC Educational Resources Information Center

This article outlines progress made towards education transformation in Wales. It explores the way in which tri-level reform is guiding system level change in Wales and looks at the implementation of the School Effectiveness Framework, which is at the heart of the reform process. It describes the way in which professional learning communities are…

Harris, Alma

2010-01-01

418

Transformations: Reflection (NLVM)  

NSDL National Science Digital Library

This Java applet enables learners to explore the reflection transformation both informally and within a coordinate system. Students select and compose shapes and manipulate the axis of symmetry (the mirror) to see the effect on a reflected image. Links to instructions, activities and teacher/parent information are included.

2011-01-01

419

Teaching, Caring, and Transformation  

ERIC Educational Resources Information Center

Educator Bell Hooks acknowledged the fundamental truth that teaching, caring, and transformation are closely linked, that is, that true teaching must be accompanied by a deep level of care in order for learning to take place. No matter how young or old, no matter the subject matter, and no matter where teaching and learning take place--a…

Nieto, Sonia

2012-01-01

420

Transformation Optics Using Graphene  

Microsoft Academic Search

Metamaterials and transformation optics play substantial roles in various branches of optical science and engineering by providing schemes to tailor electromagnetic fields into desired spatial patterns. We report a theoretical study showing that by designing and manipulating spatially inhomogeneous, nonuniform conductivity patterns across a flake of graphene, one can have this material as a one-atom-thick platform for infrared metamaterials and

Ashkan Vakil; Nader Engheta

2011-01-01

421

Discrete Gabor transform  

Microsoft Academic Search

A feasible algorithm for implementing the Gabor expansion, the coefficients of which are computed by the discrete Gabor transform (DGT), is presented. For a given synthesis window and sampling pattern, computing the auxiliary biorthogonal function of the DGT is nothing more than solving a linear system. The DGT presented applies for both finite as well as infinite sequences. By exploiting

S. Qian; D. Chen

1993-01-01

422

Is Distance Learning Transformational?  

ERIC Educational Resources Information Center

Is distance learning transformational? The author heard this question posed to a panel of faculty members during Distance Education Week activities. After reflecting upon her own students' reaction to her syllabus, her answer to the question changed from an initial, enthusiastic "yes" to a reflective "maybe," given the most favorable environment.…

Hoskins, Barbara J.

2013-01-01

423

Informing the Transformation.  

National Technical Information Service (NTIS)

Frequently Asked Questions: What is NCW. What is Power to the Edge; * Why are they critical to success in the 21st Century; * How is NCW related to transformation. To EBO; * Are NCW and Power to the Edge proving out in practice; * Are we creating new vuln...

D. S. Alberts

2005-01-01

424

A FURTHER EVALUATION OF MICROCOULOMETRY FOR ATMOSPHERIC NITRIC ACID MONITORING  

EPA Science Inventory

A coulometric instrument for measuring gaseous nitric acid is modified to improve response time characteristics and simplify operation. Possible interferences were investigated and found minimal. Comparison measurements of nitric acid by long path Fourier Transform infrared analy...

425

The Conversion of Carboxylic Acids to Ketones: A Repeated Discovery  

ERIC Educational Resources Information Center

The conversion of carboxylic acids to ketones is a useful chemical transformation with a long history. Several chemists have claimed that they discovered the conversion of carboxylic acids to ketones yet in fact the reaction is actually known for centuries.

Nicholson, John W.; Wilson, Alan D.

2004-01-01

426

Amino acids  

MedlinePLUS

Amino acids are organic compounds that combine to form proteins . Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids ...

427

Rainbow Fourier Transform  

NASA Technical Reports Server (NTRS)

We present a novel technique for remote sensing of cloud droplet size distributions. Polarized reflectances in the scattering angle range between 135deg and 165deg exhibit a sharply defined rainbow structure, the shape of which is determined mostly by single scattering properties of cloud particles, and therefore, can be modeled using the Mie theory. Fitting the observed rainbow with such a model (computed for a parameterized family of particle size distributions) has been used for cloud droplet size retrievals. We discovered that the relationship between the rainbow structures and the corresponding particle size distributions is deeper than it had been commonly understood. In fact, the Mie theory-derived polarized reflectance as a function of reduced scattering angle (in the rainbow angular range) and the (monodisperse) particle radius appears to be a proxy to a kernel of an integral transform (similar to the sine Fourier transform on the positive semi-axis). This approach, called the rainbow Fourier transform (RFT), allows us to accurately retrieve the shape of the droplet size distribution by the application of the corresponding inverse transform to the observed polarized rainbow. While the basis functions of the proxy-transform are not exactly orthogonal in the finite angular range, this procedure needs to be complemented by a simple regression technique, which removes the retrieval artifacts. This non-parametric approach does not require any a priori knowledge of the droplet size distribution functional shape and is computationally fast (no look-up tables, no fitting, computations are the same as for the forward modeling).

Alexandrov, Mikhail D.; Cairns, Brian; Mishchenko, Michael I.

2012-01-01

428

Rainbow Fourier transform  

NASA Astrophysics Data System (ADS)

We present a novel technique for remote sensing of cloud droplet size distributions. Polarized reflectances in the scattering angle range between 135° and 165° exhibit a sharply defined rainbow structure, the shape of which is determined mostly by single scattering properties of cloud particles, and therefore, can be modeled using the Mie theory. Fitting the observed rainbow with such a model (computed for a parameterized family of particle size distributions) has been used for cloud droplet size retrievals. We discovered that the relationship between the rainbow structures and the corresponding particle size distributions is deeper than it had been commonly understood. In fact, the Mie theory-derived polarized reflectance as a function of reduced scattering angle (in the rainbow angular range) and the (monodisperse) particle radius appears to be a proxy to a kernel of an integral transform (similar to the sine Fourier transform on the positive semi-axis). This approach, called the rainbow Fourier transform (RFT), allows us to accurately retrieve the shape of the droplet size distribution by the application of the corresponding inverse transform to the observed polarized rainbow. While the basis functions of the proxy-transform are not exactly orthogonal in the finite angular range, this procedure needs to be complemented by a simple regression technique, which removes the retrieval artifacts. This non-parametric approach does not require any a priori knowledge of the droplet size distribution functional shape and is computationally fast (no look-up tables, no fitting, computations are the same as for the forward modeling).

Alexandrov, Mikhail D.; Cairns, Brian; Mishchenko, Michael I.

2012-12-01

429

OVOC Emissions and Atmospheric Transformations.  

NASA Astrophysics Data System (ADS)

We quantified the main emissions from a few vegetation samples and many biomass fires using ground-based, open-path FTIR and airborne, closed-cell FTIR. The two instruments have been rigorously compared to each other and to PTR-MS and canister sampling. OVOC are major emissions from plants. OVOC account for about 70 percent of NMOC from savanna fires (the largest type of biomass burning) and 70-80 percent of NMOC from production and use of domestic biofuels (the second largest type of biomass burning). A table of average biofuel emissions is presented. Data from laboratory and free-burning fires, obtained from Alaska to South Africa, is used to develop equations that predict OVOC emissions from a wide variety of global fires. The impact of OVOC on smoke plume chemistry and the post-emission transformations of OVOC were investigated with two models. Addition of HCHO alone to the simple chemistry used in some global models dramatically reduces NOx lifetime and speeds up O3 formation rates in plumes. A detailed model verifies these effects and shows that OVOC profoundly affect formation of HOx, peroxide, and nitrogen reservoir species. The modeled photochemical transformations of OVOC are diverse, but some key pathways are unknown. We observed rapid production of both O3 and additional OVOC and OH of 1.7E7 in smoke plumes in Alaska and Africa; all reasonably consistent with model predictions. In addition, we found that cloud processing caused large post-emission changes in smoke trace gases including removal of nearly all methanol, a decrease in acetic acid, and a large increase in HCHO. These observations suggest that OVOC could react in cloud droplets and lead to production of modified aerosol. In addition, transport of OVOC by deep convection may be associated with large effects not explained by solubility alone.

Yokelson, R. J.; Christian, T. J.; Bertschi, I. T.; Ward, D. E.; Field, R. J.; Hobbs, P. V.; Goode, J.; Mason, S.; Susott, R.; Babbitt, R.; Hao, W. M.

2002-12-01

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Characterization of acid tars.  

PubMed

Acid tars from the processing of petroleum and petrochemicals using sulfuric acid were characterized by gas chromatography/mass spectrometry (GC/MS), inductively coupled plasma/optical emission spectrometry (ICP/OES), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectrometry, and scanning electron microscopy/energy dispersive X-ray (SEM/EDX) micro-analysis. Leaching of contaminants from the acid tars in 48 h batch tests with distilled water at a liquid-to-solid ratio 10:1 was also studied. GC/MS results show that the samples contained aliphatic hydrocarbons, cyclic hydrocarbons, up to 12 of the 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs), and numerous other organic groups, including organic acids (sulfonic acids, carboxylic acids and aromatic acids), phenyl, nitrile, amide, furans, thiophenes, pyrroles, and phthalates, many of which are toxic. Metals analysis shows that Pb was present in significant concentration. DSC results show different transition peaks in the studied samples, demonstrating their complexity and variability. FTIR analysis further confirmed the presence of the organic groups detected by GC/MS. The SEM/EDX micro-analysis results provided insight on the surface characteristics of the samples and show that contaminants distribution was heterogeneous. The results provide useful data on the composition, complexity, and variability of acid tars; information which hitherto have been scarce in public domain. PMID:19857924

Leonard, Sunday A; Stegemann, Julia A; Roy, Amitava

2010-03-15