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de Farias RF de Souza JM de Melo JV Airoldi C 《Journal of colloid and interface science》2000,227(1):147-151
Polyaniline deposited on As(2)O(3) surface resulted in a new material, which was characterized by infrared spectoscopy, thermogravimetry, differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, and cyclic voltammetry. The mass percentage of polymer deposited on oxide surface is approximately 13%. The scanning electron microscopy images as well as the X-ray diffraction patterns provided conclusive evidence that the oxide surface is coated by the polymer. The cyclic voltammograms of the polyaniline adsorbed on As(2)O(3) surface showed that the adsorbate exerts remarkable effects on redox processes on this oxide. The pure oxide exhibited two oxidation/reduction peaks at 0.25/-0.06 and 0.47/-0.25 V attributed tentatively to the processes As(2)O(3)(s)+6H(+)+6e(-)=2As(s)+3H(2)O and As(s)+3H(+)+3e(-)=AsH(3)(g), respectively. The polyaniline-coated sample exhibited a better-defined voltammogram in which the first oxidation peak of the oxide had its intensity increased about four times. Copyright 2000 Academic Press. 相似文献
75.
Aitala EM Amato S Anjos JC Appel JA Ashery D Banerjee S Bediaga I Blaylock G Bracker SB Burchat PR Burnstein RA Carter T Carvalho HS Costa I Cremaldi LM Darling C Denisenko K Fernandez A Gagnon P Gerzon S Gobel C Gounder K Granite D Halling AM Herrera G Hurvits G James C Kasper PA Kondakis N Kwan S Langs DC Leslie J Lichtenstadt J Lundberg B Manacero A MayTal-Beck S Meadows B de Mello Neto JR Milburn RH de Miranda JM Napier A Nguyen A d'Oliveira AB O'Shaughnessy K Peng KC Perera LP Purohit MV 《Physical review letters》1996,76(3):364-367
76.
I review recent progress on the electroweak phase transition and baryogenesis, focusing on the minimal supersymmetric Standard
Model as the source of new physics. 相似文献
77.
JM Pakarinen H Moisio S Holopainen P Vainiotalo 《Rapid communications in mass spectrometry : RCM》1999,13(14):1485-1490
2-Methoxyethanol chemical ionization of amines, carboxylic acids and amino acids has been found to produce numerous adduct ions. The most intense adduct ions for amines are [M + H](+) and [M + 77](+), for carboxylic acids [M + 27](+), [M + 59](+) and [M + 77](+), and for amino acids [M + H](+), [M + 13](+), [M + 27](+) and [M + 77](+). Either the adduct ion [M + H](+) or [M + 77](+) was the most abundant ion found for amino acids. The proton affinities of amino acids are noticed to control the formation of the [M + H](+) and [M + 77](+) ions. The relative abundance of [M + 13](+) and [M + 27](+) ions varied for different amino acids being most intense for phenylalanine and aspartic acid. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
78.
Nicolas Creusot Saïd Kinani Patrick Balaguer Nathalie Tapie Karyn LeMenach Emmanuelle Maillot-Maréchal Jean-Marc Porcher Hélène Budzinski Sélim Aït-Aïssa 《Analytical and bioanalytical chemistry》2010,396(2):569-583
Many environmental endocrine-disrupting compounds act as ligands for nuclear receptors. Among these receptors, the human pregnane
X receptor (hPXR) is well described as a xenobiotic sensor to various classes of chemicals, including pharmaceuticals, pesticides,
and steroids. To assess the potential use of PXR as a sensor for aquatic emerging pollutants, we employed an in vitro reporter
gene assay (HG5LN-hPXR cells) to screen a panel of environmental chemicals and to assess PXR-active chemicals in (waste) water
samples. Of the 57 compounds tested, 37 were active in the bioassay and 10 were identified as new PXR agonists: triazin pesticides
(promethryn, terbuthryn, terbutylazine), pharmaceuticals (fenofibrate, bezafibrate, clonazepam, medazepam) and non co-planar
polychlorobiphenyls (PCBs; PCB101, 138, 180). Furthermore, we detected potent PXR activity in two types of water samples:
passive polar organic compounds integrative sampler (POCIS) extracts from a river moderately impacted by agricultural and
urban inputs and three effluents from sewage treatment works (STW). Fractionation of POCIS samples showed the highest PXR
activity in the less polar fraction, while in the effluents, PXR activity was mainly associated with the dissolved water phase.
Chemical analyses quantified several PXR-active substances (i.e., alkylphenols, hormones, pharmaceuticals, pesticides, PCBs,
bisphenol A) in POCIS fractions and effluent extracts. However, mass-balance calculations showed that the analyzed compounds
explained only 0.03% and 1.4% of biological activity measured in POCIS and STW samples, respectively. In effluents, bisphenol
A and 4-tert-octylphenol were identified as main contributors of instrumentally derived PXR activities. Finally, the PXR bioassay provided
complementary information as compared to estrogenic, androgenic, and dioxin-like activity measured in these samples. This
study shows the usefulness of HG5LN-hPXR cells to detect PXR-active compounds in water samples, and further investigation
will be necessary to identify the detected active compounds. 相似文献
79.
Fabrício RS Pereira Andréa Alessio Maurício S Sercheli Tatiane Pedro Elizabeth Bilevicius Jane M Rondina Helka FB Ozelo Gabriela Castellano Roberto JM Covolan Benito P Damasceno Fernando Cendes 《BMC neuroscience》2010,11(1):1-13
Background
Recent studies have shown that the human right-hemispheric auditory cortex is particularly sensitive to reduction in sound quality, with an increase in distortion resulting in an amplification of the auditory N1m response measured in the magnetoencephalography (MEG). Here, we examined whether this sensitivity is specific to the processing of acoustic properties of speech or whether it can be observed also in the processing of sounds with a simple spectral structure. We degraded speech stimuli (vowel /a/), complex non-speech stimuli (a composite of five sinusoidals), and sinusoidal tones by decreasing the amplitude resolution of the signal waveform. The amplitude resolution was impoverished by reducing the number of bits to represent the signal samples. Auditory evoked magnetic fields (AEFs) were measured in the left and right hemisphere of sixteen healthy subjects.Results
We found that the AEF amplitudes increased significantly with stimulus distortion for all stimulus types, which indicates that the right-hemispheric N1m sensitivity is not related exclusively to degradation of acoustic properties of speech. In addition, the P1m and P2m responses were amplified with increasing distortion similarly in both hemispheres. The AEF latencies were not systematically affected by the distortion.Conclusions
We propose that the increased activity of AEFs reflects cortical processing of acoustic properties common to both speech and non-speech stimuli. More specifically, the enhancement is most likely caused by spectral changes brought about by the decrease of amplitude resolution, in particular the introduction of periodic, signal-dependent distortion to the original sound. Converging evidence suggests that the observed AEF amplification could reflect cortical sensitivity to periodic sounds. 相似文献80.
D.S. Bhange C. Dejoie F. Porcher N. Malikova P. Martinetto E. Dooryhée M. Anne 《The European physical journal. Special topics》2010,189(1):279-284
The present work focuses on the dynamic studies of N’N-dimethyl-paranitroaniline (dmpNA) encapsulated in silicalite zeolite.
Quasielastic neutron scattering (QENS) experiments are carried out using neutron spin-echo technique. Polarisation of the
scattered neutron beam is measured at carefully chosen values of Q = 0.35, 0.9, 1.1 and 1.45 ?−1 at fixed T = 298 K and at fixed Q = 0.9 ?−1 at 150, 200, 250 and 298 K. This gives insight into the motion and the related activation energy of the guest dmpNA molecule.
The quasielastic signal observed in the present system within the time range considered is due to fast local rotational motions
of protons of the end methyl groups. The results are in good agreement with the dynamics of methyl group rotations reported
in the literature by back-scattering QENS technique. 相似文献