Symbolic squares in regular local rings

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     

Carbohydrate chain of ganglioside GM1 as a ligand: identification of the binding strategies of three 15 mer peptides and their divergence from the binding modes of growth-regulatory galectin-1 and cholera toxin

The branched pentasaccharide chain of ganglioside GM1 is a prominent cell surface ligand, for example, for cholera toxin or tumor growth-regulatory homodimeric galectins. This activity profile via protein recognition prompted us to examine the binding properties of peptides with this specificity. Our study provides insights into the mechanism of molecular interaction of this thus far unexplored size limit of the protein part. We used three pentadecapeptides in a combined approach of mass spectrometry, NMR spectroscopy and molecular modelling to analyze the ligand binding in solution. Availability of charged and hydrophobic functionalities affected the intramolecular flexibility of the peptides differently. Backfolding led to restrictions in two cases; the flexibility was not reduced significantly by association of the ligand in its energetically privileged conformations. Major contributions to the interaction energy arise from the sialic acid moiety contacting Arg/Lys residues and the N-terminal charge. Considerable involvement of stacking between the monovalent ligand and aromatic rings could not be detected. This carbohydrate binding strategy is similar to how an adenoviral fiber knob targets sialylated glycans. Rational manipulation for an affinity enhancement can now be directed to reduce the flexibility, exploit the potential for stacking and acquire the cross-linking capacity of the natural lectins by peptide attachment to a suitable scaffold.     

Simultaneous determination of alkylphenol ethoxylates and their biotransformation products by liquid chromatography/electrospray ionisation tandem mass spectrometry

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.     

Revisiting the S-Au(111) interaction: static or dynamic?

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.     

Darstellung von polyfluororganotrichlorsilanen

The following substances could be prepared by Grignard reactions or by conversions with trichlorosilane: C₆F₅CH₂CHCH₂, C₆F₅(CH₂)₃SiCl₃, CF₃(CF₂)₉CH₂CHCH₂, CF₃(CF₂)₇(CH₂)₂SiCl₃, CF₃(CF₂)₁₁(CH₂)₃CHCH₂ und CF₃(CF₂)₁₁(CH₂)₅SiCl₃.They were characterized by spectroscopical and microanalytical methods.     

Characterization of H2 binding sites in prototypical metal-organic frameworks by inelastic neutron scattering

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.     

Chemical Composition of Tagetes patula Flowers Essential Oil and Hepato-Therapeutic Effect against Carbon Tetrachloride-Induced Toxicity (In-Vivo)

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.     

Plasma Polymerization Inside Tubes in Hexamethyldisiloxanes and Ethyne Glow Discharges: Effects of Deposition Atmosphere on Wetting and Ageing in Solvents

The coating deposition inside tubes becomes increasingly important for fluidic applications, in which inner surfaces are chemically and mechanically strained by the flowing liquid and by scratching of particles. The developed process for tube coating, presented in this work, is based on the discharge in the precursor gas atmosphere between two mesh electrodes at the ends of the tube. The gas mixture is introduced on one end and pumped through the electrode on the other end. Igniting plasma inside the tube, the tube walls are the barrier to the atmosphere. Especially pulsed DC discharges for plasma polymerization in this alignment lead to good coating results, which is shown in this work focusing on deposition in pure and mixed hexamethyldisiloxane, ethyne, and oxygen atmospheres. Chemical binding, wetting, and ageing are strongly influenced by the choice of the gas mixtures. Sufficient oxygen partial pressure in the deposition atmosphere leads to hydrophilic behavior of the SiO₂-like polymer-like carbon coatings, all other applied atmospheres to generally hydrophobic behavior of pure and Si-doped plasma polymers, respectively.     

Inactivation of Vaccinia Virus by Natural Sunlight and by Artificial UVB Radiation

This study determined the sensitivity of vaccinia virus, an orthopox virus commonly used as a surrogate for variola virus (etiological agent of smallpox), exposed to UVB radiation emitted by a solar simulator, or to direct natural sunlight. The data obtained indicate that: (1) the virucidal effect of natural sunlight can be mimicked adequately by an artificial light source with similar spectral characteristics in the UVB, (2) viral sensitivity to UVB or to solar radiation can be correlated with experimental data previously obtained with UVC, (3) the correlation factor between virus inactivation by solar radiation (measured at 300 ± 5 nm) and by UVC (254 nm) is between 33 and 60, and (4) the sensitivity of viruses either dry on glass surfaces or in liquid suspension is similar when in the presence of similar amounts of cellular debris and growth media. The findings reported in this study should assist in estimating the threat posed by the persistence of virus during epidemics or after an accidental or intentional release.