Search results for "Ethylene"
showing 10 items of 2589 documents
Chromoscopy-Guided Endomicroscopy Increases the Diagnostic Yield of Intraepithelial Neoplasia in Ulcerative Colitis
2007
Background & Aims: Because of the large number of biopsy specimens, surveillance colonoscopy in ulcerative colitis (UC) is currently time consuming and significant flat lesions still may be missed. In this study we assessed the value of combined chromoscopy and endomicroscopy for the diagnosis of intraepithelial neoplasias in a randomized controlled trial. Methods: A total of 161 patients with long-term UC in clinical remission were randomized at a 1:1 ratio to undergo conventional colonoscopy or chromoscopy with endomicroscopy. Eight patients were excluded because of insufficient bowel preparation. In the conventional colonoscopic group (n = 73), random biopsy examinations and targeted bio…
Impact of bioactive packaging systems based on EVOH films and essential oils in the control of aflatoxigenic fungi and aflatoxin production in maize.
2017
Aspergillus flavus and A. parasiticus are the most common fungal species associated with aflatoxin (AF) contamination of cereals, especially maize, and other agricultural commodities. AFB1, the most frequent and toxic metabolite, is a powerful hepatotoxic, teratogenic and mutagenic compound. Effective strategies to control these fungal species and AFs in food and feed are required. Active packaging film containing essential oils (EO) is one of the most innovative food packaging concepts. In this study, ethylene-vinyl alcohol (EVOH) copolymer films incorporating EO from Origanum vulgare (ORE), Cinnamomum zeylanicum (CIN) or their major active constituents, carvacrol (CAR) and cinnamaldehyde …
Thermodynamic Behavior of Non-Ionic Tri-block Copolymers in Water at Three Temperatures
2006
Apparent molar volumes (V Φ) of aqueous solutions of some copolymers, based on ethylene oxide (EO) and propylene oxide (PO) units, were determined as functions of concentration at three temperatures. Viscosity measurements were also carried out on some of these systems. The effects studied include how the molecular architecture and the molecular weight affect the aggregation of the copolymer, keeping constant the EO/PO ratio. Modeling of the volumetric data yielded the partial molar volume of the copolymer in the standard (V°) and the aggregated (V M) states, as well as the equilibrium constant for micellization and the aggregation number. Analysis of the viscosity data supported the insigh…
Hormonal regulation of S-adenosylmethionine synthase transcripts in pea ovaries
1996
Two cDNA clones coding for S-adenosyl-L-methionine synthase (SAMs, EC 2.5.1.6) have been isolated from a cDNA library of gibberellic acid-treated unpollinated pea ovaries. Both cDNAs were sequenced showing a high degree of identity but coding for different SAMs polypeptides. The presence of two SAMs genes in pea was further confirmed by Southern analysis. Expression of the SAMs genes in the pea plant was found at different levels in vegetative and reproductive tissues. We characterized the expression levels of SAMs genes during the development or senescence of pea ovaries. Northern analysis showed that transcription of SAMs genes in parthenocarpic fruits was upregulated by auxins in the sam…
Effect of adolescent exposure to WIN 55212-2 on the acquisition and reinstatement of MDMA-induced conditioned place preference.
2009
The present study employs a conditioned place preference procedure (CPP) to examine the effects of exposure to the cannabinoid agonist WIN 55212-2 (WIN) (0.1 and 0.5mg/kg) during adolescence on the reinforcing properties of +/-3,4-methylenedioxymetamphetamine hydrochloride (MDMA) (1.25 and 2.5mg/kg) in mice. On postnatal day (PD) 27, animals received a daily injection of the assigned treatment on 5 consecutive days, and three days later the place conditioning procedure was initiated (PD 35). The results suggest that pre-exposure to cannabinoids strengthens the properties of MDMA and favors reinstatement of the craving for the drug, which endorses the gateway hypothesis.
Multivariate Metal-Organic Frameworks for the Simultaneous Capture of Organic and Inorganic Contaminants from Water
2019
We report a new water-stable multivariate (MTV) Metal-Organic Framework (MOF) prepared by combining two different oxamide-based metalloligands derived from the natural amino acids L-serine and L-methionine. This unique material features hexagonal channels decorated with two types of flexible and functional 'arms' (-CH2OH and -CH2CH2SCH3) capable to act, synergistically, for the simultaneous and efficient removal of both inorganic (heavy metals like Hg2+, Pb2+ and Tl+) and organic (dyes such as Pyronin Y, Auramine O, Brilliant Green and Methylene Blue) contaminants and, in addition, this MTV-MOF is completely reusable. Single-crystal X-ray diffraction (SCXRD) measurements allowed to solve th…
Synthesis of tritium labeled 7α-methoxycarbonyl-15β,16β-methylene-3-oxo-17α-pregn-4-ene-21, 17-carbolactone, [3H]SH-D515, a highly selective tracer f…
1988
The synthesis of 7α-methoxycarbonyl-15β,16β-methylene-3-oxo-17α-pregn-4-ene-21,17-carbolactone (5, SH-D515, ZK 91587), a potent aldosterone antagonist exhibiting a strong and very selective binding to the mineralocorticoid receptor and the tritiated analog 6 is reported.
Monolayers of asymmetrical diethylalkanoat disulfides on gold(111):.the influence of chain length difference on atomic force microscope images
1998
Several symmetrical and asymmetrical long-chain diethylalkanoat disulfides were synthesized and character- ized. The differences in the chain lengths of the disul- fides ranged between zero and five methylene units. Self- assembled monolayers of these disulfides formed on Au(111) surfaces were studied by atomic force microscopy (AFM) in order to obtain information about the origin of the image contrast. Domains with hexagonal lattices (lattice constants 5:2- 5:3 A) were detected for all derivatives, independent of the chain length differences. This indicates that the contrast arises roughly at a depth of 4- 8 A in the monolayers at imag- ing forces between 0: 2a nd 3n N. For SAMs of diethyl…
Static and Dynamic Properties of a n-C100H202 Melt from Molecular Dynamics Simulations
1997
We present in this work results from atomistic molecular dynamics simulations of a n-C100H202 melt. This work represents a first effort to simulate a fully equilibrated ensemble of chains of suffic...
Cracking of n-heptane on a hzsm-5 zeolite. The influence of acidity and pore structure
1985
Abstract The crackino of n-heptane on a HZSM-5 zeolite has been studied in a continuous qlass flow reactor, at atmospheric pressure, up to 470°C. The initial selectivities to the different reaction products, kinetic rate constants, activation energies and decay parameters have been calculated and compared with those obtained using a large pore zeolite (HYUS). A different product distribution is obtained with the two zeolites. In that way, and considering initial selectivities, different C 6 /C 1 , C 5 /C 2 , C 4 /C3, i-C 4 /n-C 4 , ethylene/ethane, propylene/propane ratios have been found on the two zeolite catalysts. The results have been quantitatively explained by considerinq a direct cr…