A negative answer to a question about leading terms ideals of polynomial ideals

We construct an example of a finitely generated ideal $I$ of $R\left[X\right]$, where $R$ is a one-dimensional domain, whose leading terms ideal is not finitely generated. This gives a negative answer to the open question of whether if $R$ is a domain with Krull dimension ≤1, then for any finitely generated ideal $I$ of $R\left[X\right]$, the leading terms ideal of $I$ is also finitely generated. Moreover, as a positive part of our answer, we prove that for any one-dimensional domain $R$ and any $a,b\in R$, the ideal of $R\left[X\right]$ generated by the leading terms of $〈1+aX,b〉$ is finitely generated.     

Trimethylsilyl group migrations in cryogenic ozonolysis of trimethylsilylethene: evidence for nonconcerted primary ozonide decomposition pathway

The identification of trimethylsiloxy-1,2-dioxetane and 2-trimethylsilyloperoxyacetaldehyde and assignment of trimethylsiloxymethyl formate as products of the low-temperature ozonolysis of trimethylsilylethene demonstrate feasibility of migrations of trimethylsilyl group in a dioxygen-centered (oxyperoxy) diradical produced via a homolytic cleavage of each of both O-O bonds in the primary ozonide. The results provide the first experimental evidence on the nonconcerted decomposition of the primary ozonide.     

IR laser ablative modification of poly(ethylene-co-acrylic acid) zinc salt

IR laser-induced ablative degradation of poly(ethylene-co-acrylic acid) zinc salt (PEAZn) leads to cleavage of both polyethylene backbone and CO₂H group. It yields carbon oxides and volatile hydrocarbons (ethene as a major product) and affords ablative deposition of solid ionomeric films in which the initial ratio -CO₂H/-CO₂Zn is decreased due to higher thermal stability of the -CO₂Zn group. The laser-induced process differs remarkably from conventional degradation of similar polyethylene chain-based metal methacrylate ionomers that are known to yield cold ring fraction containing only -CO₂H group. The cleavage of the polyethylene backbone in the laser-induced degradation becomes more important at higher fluences. The presence of sodium metasilicate is shown to accelerate the decomposition of the CO₂H group.     

The comparative molecular surface analysis (COMSA)--a nongrid 3D QSAR method by a coupled neural network and PLS system: predicting pK(a) values of benzoic and alkanoic acids

A self-organizing neural network was used to design a novel method capable of the quantitative prediction of molecular properties. The method is based on the comparison of molecular surfaces performed by the coupled neural network and PLS system. Unlike CoMFA and related methods it does not compare the properties describing a discrete set of points but the average property values calculated for a certain area of the molecular surface. It has been found that the results of the PLS analysis of the series of the comparative matrices of the molecular electrostatic potential (MEP) are quite stable. Also the results only slightly depend on such parameters as the number of points sampled at the molecular surface (D) or a winning distance (MD) of the self-organizing neurons. The influence of these parameters for modeling the effects limited by steric and electronic effects was determined and the pK(a) values of the ortho-, meta-, and para- (o-, m-, p-) analogues of benzoic acid and selected alkanoic acids were predicted. We generally found that for the series analyzed CoMSA gave better models than CoMFA.     

Laser-induced chemistry in silane-hexafluoroacetone mixtures for production of novel Si/C/F/O and C/F/O materials

Chemical reactions induced by CO₂-laser radiation in mixtures of silane and hexafluoroacetone afford various gaseous silicon- and carbon-containing compounds and result in deposition of microstructures of carbon, C/F/O and Si/C/O/F materials. These products are suggested to be formed by a variety of exothermic reactions initiated through SiH₄-photosensitized decomposition of hexafluoroacetone. Silane is shown to be a very potent reagent for the reduction of C-F bonds.     

Laser‐induced dielectric breakdown in tetramethylgermane/tetramethyltin mixtures: deposition of nanostructured Sn/Ge/C and Ge?Sn/C films

Transversely Excited Atmospheric (TEA) CO₂ laser‐irradiation of gaseous tetramethylgermane (TMG)–tetramethyltin (TMT) mixtures in Ar results in decomposition of both organometallic compounds and in chemical vapour deposition of nanostructured films analyzed by FTIR and Raman spectroscopy, X‐ray diffraction and electron microscopy. They were shown to have similar morphology and elemental composition and constituents dependent on the TMG–TMT ratio. The analyses confirm the presence of nanosized carbon‐rich (graphitic) structures that incorporate C? M and M? M (M ?Ge, Sn) bonds containing an amorphous phase together with crystalline, either β‐Sn or metastable Sn‐rich Ge? Sn alloy. The unique latter constituent is favored at high concentrations of TMG precursor. Copyright © 2010 John Wiley & Sons, Ltd.     

The surface characteristics of polycrystalline cobalt electrooxidised in sulfuric acid solutions

The oxidation of cobalt electrodes has been carried out by means of cyclic voltammetry and coulometry under controlled potential in sulfuric acid solutions of different concentrations. The electrochemical scanning tunneling microscope/scanning tunneling microscope (ECSTM/STM) systems constructed by the authors and scanning electron microscopy (SEM) with the SEM-EDX system of surface analysis of the elements have been used. The procedure applied in this work made it possible to observe the fragments of the same surface by means of SEM and ECSTM/STM. The most typical images for a polycrystalline Co electrode with a ±10% accuracy at the scales of 4800 nm × 4800 nm and 100 nm × 100 nm are presented and the results are discussed. In a diluted electrolyte (0.1 M), irregular forms of a stable cobalt oxide with Co:O ratio ∼1:1 appear. Unreproducible results have been obtained in a 1.0 M H₂SO₄ solution. Compact and relatively regular layers of cobalt oxide of the same ratio have been obtained in 0.1 M H₂SO₄, as well as in 10.0 M sulfuric acid solution, under controlled oxidation potential at the passivation range. Received: 6 January 1999 / Accepted: 5 May 1999     

Anwendung von29Si-KMR zur Analyse der silylierten Verbindungen. KMR-Spektren von (CH3)3Si-O-C-Derivaten

Ohne Zusammenfassung     

“Clickable” and Antifouling Block Copolymer Brushes as a Versatile Platform for Peptide‐Specific Cell Attachment

To tailor cell–surface interactions, precise and controlled attachment of cell‐adhesive motifs is required, while any background non‐specific cell and protein adhesion has to be blocked effectively. Herein, a versatile and highly reproducible antifouling surface modification based on “clickable” groups and hierarchically structured diblock copolymer brushes for the controlled attachment of cells is reported. The polymer brush architecture combines an antifouling bottom block of poly(2‐hydroxyethyl methacrylate) poly(HEMA) and an ultrathin azide‐bearing top block, which can participate in well‐established “click” reactions including the highly selective copper‐catalyzed alkyne‐azide cycloaddition (CuAAC) reaction under mild conditions. This straightforward approach allows the rapid conjugation of a cell‐adhesive, alkyne‐bearing cyclic RGD peptide motif, enabling subsequent specific attachment of NIH 3T3 fibroblasts, their extensive proliferation and confluent cell sheet formation after 48 h of incubation. The generally applicable strategy presented in this report can be employed for surface functionalization with diverse alkyne‐bearing biological moieties via CuAAC or copper‐free alkyne‐azide cycloaddition protocols, making it a versatile functionalization approach and a promising tool for tissue engineering, biomaterial implant design, and other applications that require surfaces supporting highly specific cell attachment.