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1.
2.
In this paper we prove for several classes of ideals in regular local rings of equicharacteristic 0 that the symbolic square
of the ideal contains no minimal generator of the ideal. Our techniques come from residual intersections, integral closures
of ideals, and differentials.
Received January 14, 1997; in final form March 20, 1997 相似文献
3.
Reversed-phase LC-MS/MS is used to determine major estrogenic alkylphenol ethoxylates (APEOs) and their biotransformation products. It allows the simultaneous analysis of eight APEOs, alkylphenoxy carboxylates (APECs) and alkylphenols (APs) in sewage treatment plant (STP) effluents in the same extract after solid-phase enrichment on polymeric Oasis HLB. As precursor ions, [APEO + NH4]+, [APEC - H]- and [AP - H]- were monitored. Instrumental limits of detection (LOD) were 2-600 pg, corresponding to sample concentrations of 0.04-12 ng l(-1), without correction for overall method recoveries. Matrix-induced signal suppression during electrospray ionisation (ESI) and extraction as well as overall method recoveries were assessed and the suitability of deuterated surrogates as internal standards was evaluated. 相似文献
4.
Biener MM Biener J Friend CM 《Langmuir : the ACS journal of surfaces and colloids》2005,21(5):1668-1671
The Au-S interaction is probably the most intensively studied interaction of Au surfaces with nonmetals, as, for example, it plays an important role in Au ore formation(1) and controls the structure and dynamics of thiol-based self-assembled monolayers (SAMs). Various S-induced surface structures on Au(111) were recently reported for different conditions and predominantly interpreted in terms of a static Au surface. Here, we demonstrate that the Au(111) surface exhibits a very dynamic character upon interaction with adsorbed sulfur: large-scale surface restructuring and incorporation of Au atoms into a growing 2D AuS phase were observed in situ. These results provide new insight into the Au-S surface chemistry. 相似文献
5.
Hubbuch J Linden T Knieps E Ljunglöf A Thömmes J Kula MR 《Journal of chromatography. A》2003,1021(1-2):93-104
An experimental study on the interplay of sorbent structure and fluid phase conditions (pH) has been carried out examining adsorption and transport of bovine serum albumin (BSA) and a monoclonal antibody (IgG 2a) on SP Sepharose Fast Flow and SP Sepharose XL. SP Sepharose Fast Flow is characterised by a relatively open pore network, while SP Sepharose XL is a composite structure with ligand-carrying dextran chains filling the pore space. Both adsorbents have similar ionic capacity. Protein transport and adsorption profiles were evaluated using confocal laser scanning microscopy. Under all investigated conditions, BSA uptake could be adequately explained by a pore diffusion mechanism. The adsorption profiles obtained for IgG 2a, however, indicated that changes in fluid phase conditions as well as a change in the solid phase structure could result in a more complex uptake mechanism as compared to pore diffusion alone. This mechanism results in a fast transport of proteins into the adsorbent, followed by an overshoot of protein in the center of the sorbent and a setback towards a homogeneous adsorption profile. 相似文献
6.
The following substances could be prepared by Grignard reactions or by conversions with trichlorosilane: C6F5CH2CHCH2, C6F5(CH2)3SiCl3, CF3(CF2)9CH2CHCH2, CF3(CF2)7(CH2)2SiCl3, CF3(CF2)11(CH2)3CHCH2 und CF3(CF2)11(CH2)5SiCl3.They were characterized by spectroscopical and microanalytical methods. 相似文献
7.
The hindered rotor transitions of H(2) adsorbed in the chemically related and prototypical porous metal-organic frameworks IRMOF-1, IRMOF-8, IRMOF-11, and MOF-177 were studied by inelastic neutron scattering to gain information on the specifics of H(2) binding in this class of adsorbents. Remarkably sharp and complex spectra of these materials signify a diversity of well-defined binding sites. Similarities in the spectral features as a function of H(2) loading and correlations with recent crystallographic studies were used to assign transitions ranging in rotational barrier from <0.04 to 0.6 kcal/mol as corresponding to localized adsorption sites on the organic and inorganic components of these frameworks. We find that binding of H(2) at the inorganic cluster sites is affected by the nature of the organic link and is strongest in IRMOF-11 in accord with our adsorption isotherm data. The sites on the organic link have lower binding energies, but a much greater capacity for increases in H(2) loading, which demonstrates their importance for hydrogen uptake by these materials. 相似文献
8.
Hedin N Graf R Christiansen SC Gervais C Hayward RC Eckert J Chmelka BF 《Journal of the American Chemical Society》2004,126(30):9425-9432
The structure of a novel molecularly ordered two-dimensional (2D) silicate framework in a surfactant-templated mesophase has been established by using a combination of solid-state nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction, and quantum chemical and empirical force-field modeling. These materials are unusual in their combination of headgroup-directed 2D crystalline framework ordering, zeolite-like ring structures within the layers, and long-range mesoscopic organization without three-dimensional (3D) atomic periodicity. The absence of registry between the silicate sheets, resulting from the liquidlike disorder of the alkyl surfactant chains, has presented significant challenges to the determination of framework structures in these and similar materials lacking 3D crystalline order. Double-quantum (29)Si NMR correlation experiments establish the interactions and connectivities between distinct intra-sheet silicon sites from which the structure of the molecularly ordered inorganic framework is determined. 相似文献
9.
Hanan Y. Aati Mahmoud Emam Jawaher Al-Qahtani Sultan Aati Abdulrahman Aati Juergen Wanner Mohamed M. Seif 《Molecules (Basel, Switzerland)》2022,27(21)
The liver is a crucial organ among body organs due to its wide functions, in particular, detoxification and metabolism. Exposure to detrimental chemicals or viral infections may provoke liver dysfunction and ultimately induce liver tissue damage. Finding natural substances for liver disease treatment to overcome the conventional treatments’ side effects has attracted the attention of researchers worldwide. Our current work was conducted to investigate the hepato-therapeutic activities of essential oil (EO) isolated from Tagetes patula flowers. EO was extracted using the hydro-distillation (HD) technique and its chemical composition was identified by GC/MS. Then, the hepatic treatment potential of extracted EO was evaluated in vivo against CCL4 in rats. HD of T. patula flowers yielded highly chemical constituents of EO along with significant antioxidant potential. A coherent molecular network was fashioned via the Global Natural Products Social Molecular Networking (GNPS) to visualize the essential components and revealed that the sesquiterpene (E)-β-caryophyllene was the most predominant volatile constituent which accounted for 24.1%. The treatment of CCL4 led to significant induced oxidative stress markers malonaldehyde, total protein, and non-protein sulfhydryl, as well as elevated serum aminotransferase, gamma-glutamyl transferase, alkaline phosphatase, and bilirubin. In addition, it disrupted the level of lipid profile. The post-treatment using T. patula EO succeeded in relieving all toxic effects of CCl4 and recuperating the histopathological signs induced by CCL4. Silymarin was used as a standard hepatoprotective agent. The obtained results demonstrated that the extracted EO exerted high protective activities against the toxicity of CCL4. Moreover, the T. patula flowers EO can be used as a natural remedy to relieve many contemporary liver diseases related to oxidative stress. 相似文献
10.