One-Dimensional p-Adic Subanalytic Sets

In this paper we extend two theorems from [2] on p-adic subanalyticsets, where p is a fixed prime number, Q_p is the field of p-adicnumbers and Z_p is the ring of p-adic integers. One of thesetheorems [2, 3.32] says that each subanalytic subset of Z_p issemialgebraic. This is extended here as follows.     

Investigation of the validity of the kinetic plot method to predict the performance of coupled column systems operated at very high pressures under different thermal conditions

The present study investigates how strong the kinetic plot method is influenced by the changes in plate height, retention factor and apparent column permeability that arise under conditions of very high pressure. More precisely, the study investigates how well a set of performance measurements conducted on a single short column can be used to predict the performance of a long sequence of coupled columns. This has been investigated for the two practically most relevant thermal conditions, i.e., that of a forced-air oven and that of a still-air oven. Measuring column performance data for acetophenone and benzene on a series of coupled 3.5 μm columns that could be operated up to 1000 bar, it was found that the kinetic plot method provides accurate predictions of time versus efficiency for the still-air oven systems, over the entire range of investigated pressures and column lengths (up to 60 cm), provided k′ and K_v0 are evaluated at the maximal pressure. For the forced-air oven which leads to worse performances than the still-air oven, the kinetic plot prediction is less accurate, partly because the thermal conditions (near-isothermal) tend to vary if the number of coupled columns increases. The fact that the thermal conditions of the column wall might vary with the column length is an additional complexity making very-high pressure separations less predictable and harder to interpret and model.     

Semi‐supervised linear discriminant analysis

Fisher's linear discriminant analysis is one of the most commonly used and studied classification methods in chemometrics. The method finds a projection of multivariate data into a lower dimensional space so that the groups in the data are well separated. The resulting projected values are subsequently used to classify unlabeled observations into the groups. A semi‐supervised version of Fisher's linear discriminant analysis is developed so that the unlabeled observations are also used in the model‐fitting procedure. This approach is advantageous when few labeled and many unlabeled observations are available. The semi‐supervised linear discriminant analysis method is demonstrated on a number of data sets where it is shown to yield better separation of the groups and improved classification over Fisher's linear discriminant analysis. Copyright © 2011 John Wiley & Sons, Ltd.     

Low-medium resolution HLA-DQ2/DQ8 typing for coeliac disease predisposition analysis by colorimetric assay

Coeliac disease is an inflammation of the small intestine, occurring in genetically susceptible individuals triggered by the ingestion of gluten. Human Leukocyte Antigens (HLA) DQ2 and DQ8 gene have been identified as key genetic factors in coeliac disease as they are presented in almost 100 % of the patients. These genes are encoded by the combination of certain alleles in the DQA and DQB region of chromosome 6. Specifically, DQA1*05:01 and DQB1*02:01 alleles for serologically defined leukocyte antigen DQ2 cis, DQA1*05:05 and DQB1*02:02 for DQ2 trans and DQA1*03:01 and DQB1*03:02 alleles for the DQ8. Specific identification of these alleles is a challenge due to the high number of alleles that have been identified so far: 46 in the DQA region and 160 in the DQB region (as of IMGT/HLA Database 10/2011 release). In the reported work, the development of a multiplex colorimetric assay for the low to medium HLA typing of the DQ2 and DQ8 genes is presented. The optimisation of probe design and assay conditions, performed by both surface plasmon resonance and enzyme-linked oligonucleotide assay, are reported. Finally, the performances of the developed typing platform were validated by the analysis of real patient samples and HLA typing, compared with those obtained using hospital based typing technology and an excellent correlation obtained.     

Performance limits and kinetic optimization of parallel and serially connected multi-column systems spanning a wide range of efficiencies for liquid chromatography

Using a set of experimentally determined liquid chromatography column performance data, it has been investigated how a range of efficiencies can best be covered when using a multi-column system. Two main variants are considered: a serially-connected variant (realizing different column lengths by connecting a different number of column segments in series) and a parallel-connected variant (realizing different column lengths by simply switching between columns with a different length arranged in parallel). Both variants are compared for their ability to keep the average analysis time along a given range of efficiencies as close as possible to the intrinsic Knox & Saleem-speed limit. It was found that the serial connection mode offers a better compromise between average speed and amount of required silica (total required column length) than the parallel connection mode for all efficiency ranges running from 5000–10,000 plates up to 75,000–150,000 plates. Considering an ultra-high performance liquid chromatography (UHPLC) operation at 1200 bar, the best possible serial connection system can get within about within 15–25% of the Knox & Saleem-speed limit, whereas a three-column parallel system can only get to within 40–50% of the speed limit, while needing 50–100% more total column length. In absolute terms, the serially-connected system with individually optimized segment lengths should be able to cover a range of 5000–75,000 theoretical plates (dynamic range of 25) in an average analysis time of 14.3 min when using a 1200 bar instrument. At 400 bar, this would be 37.9 min, showing that the construction of wide-efficiency range systems would be one of the application areas where the advantages of UHPLC-conditions would be most fully realized.     

Mechanical and structural properties of native and alkali-treated bacterial cellulose produced by Gluconacetobacter xylinus strain ATCC 53524

Mechanical properties of hydrated bacterial cellulose have been tested as a function of fermentation time and following the alkali treatment required for sterilisation prior to biomedical applications. Bacterial cellulose behaves as a viscoelastic material, with brittle failure reached at approximately 20% strain and 1.5 MPa stress under uniaxial tension. Treatment with 0.1 M NaOH resulted in minimal effects on the mechanical properties of bacterial cellulose. Fermentation time had a large effect on both bacterial numbers and cellulose yield but only minor effects on mechanical properties, showing that the fermentation system is a robust method for producing cellulose with predictable materials properties. The failure zone in uniaxial tension was shown to be associated with large-scale fibre alignment, consistent with this being the major determinant of mechanical properties. Under uniaxial tension, elastic moduli and failure stresses are an order of magnitude lower than those obtained under biaxial tension, consistent with the fibre alignment mechanism which is not available under biaxial tension.     

Boundedly complete weak-Cauchy basic sequences in Banach spaces with the PCP

It is proved that every non-trivial weak-Cauchy sequence in a Banach space with the PCP (the Point of Continuity Property) has a boundedly complete basic subsequence. The following result, due independently to S. Bellenot and C. Finet, is then deduced as a corollary. If a Banach space X has separable dual and the PCP, then every non-trivial weak-Cauchy sequence in X has a subsequence spanning an order-one quasi-reflexive space.     

The Controlled Oxidation of Organic Sulfides to Sulfoxides with the Help of O-Iodosylbenzoic Acid

The oxidation procedure plus a simple preparation of oiodosylbenzoic acid are described.