Measurement of strain fields near coldworked holes

Residual strains near coldworked holes were measured for several degrees of radial expansion. Moiré-grating photography created magnified replicas of deformed gratings. Fringe patterns with sensitivity multiplication and S/N improvement were obtained by optical data processing and by using slotted apertures for photography. Computer data reduction and plotting provided the required strain maps.     

Comparison of the three-phase oil relative permeability models

A comparative study of seven different methods for predicting three-phase oil relative permeabilities in the presence of gas and water phases is presented. Predicted oil relative permeabilities from these correlations have been compared with published three-phase experimental data obtained in Berea sandstone core samples. Some of the correlations under study have been recently developed and have never been tested against the laboratory data.The comparison shows that the commonly used models such as Stones' often do not give accurate predictions of the experimental data. It is concluded that the recently developed models fit the experimental data as well as or better than the previously developed and widely used three-phase oil relative permeability models.     

A composite Bayesian hierarchical model of compositional data with zeros

We present an effective approach for modelling compositional data with large concentrations of zeros and several levels of variation, applied to a database of elemental compositions of forensic glass of various use types. The procedure consists of the following: (i) partitioning the data set in subsets characterised by the same pattern of presence/absence of chemical elements and (ii) fitting a Bayesian hierarchical model to the transformed compositions in each data subset. We derive expressions for the posterior predictive probability that newly observed fragments of glass are of a certain use type and for computing the evidential value of glass fragments relating to two competing propositions about their source. The model is assessed using cross‐validation, and it performs well in both the classification and evidence evaluation tasks. Copyright © 2014 John Wiley & Sons, Ltd.     

Synthesis and Crystallographic Study of <Emphasis Type="Italic">N</Emphasis>′-(1-benzylpiperidin-4-yl)acetohydrazide

Abstract  

As part of a study into new Fentanyl-derived opioid compounds with potent analgesic activity and reduced side effects the starting material title compound, C₁₄H₂₁N₃O (1), was synthesized and characterized by NMR spectroscopy and single-crystal X-ray diffraction. The crystal structure is monoclinic Cc with unit cell parameters a = 14.1480(3) ?, b = 14.1720(4) ?, c = 27.6701(7) ?, β = 96.956(1)°, α = γ = 90°. The compound has crystallized with four crystallographically unique molecules in the asymmetric unit; each molecule has a very similar conformation and an analysis of the structure shows that although all four unique molecules overlay very well there is no evidence of pseudo-symmetry which would relate the molecules in the higher symmetry space group C2/c. The crystal packing consists of two separate hydrogen bonded chains which are linked together to form a thick 2D structure in the ab plane.     

Characterization of plasma polymerized C, H, and O containing compounds by MALDI mass spectrometry

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is used for the first time to characterize radio frequency plasma-deposited polymers and for investigation of the plasma polymerization process. The MALDI mass spectra of the plasma polymers of allyl alcohol, di(ethylene glycol) vinyl ether and ethylene glycol butyl vinyl ether are all reported using solvent-based MALDI sample preparation approaches. The MALDI mass spectra of each of the three plasma polymers contain distinctive polymer series ion signals having molecular weight distributions below 2000 Da. Unexpectedly, however, the ion signals from each of the three plasma polymers show a common polymer repeat unit of 44 Da, for which the chemical formula is most likely -(C(2)H(4)O)-, and no evidence of the expected radical chain polymerization polymer is detected. These results are discussed in terms of the likely involvement of gas-phase radical species having different stabilities in the radio frequency plasma environment.     

Enhancement of deoxyribonucleic acid microarray performance using post-hybridization signal amplification

Microarray performance depends upon the ability to screen samples against a vast array of probes with the appropriate sensitivity and selectivity. While these factors are significantly influenced by probe design, they are also subject to the particular detection methodology and reagents employed. Herein we describe the incorporation of super avidin-biotin system (SABS) and secondary enzymatic enhancement (SEE) as post-hybridization signal amplification techniques to improve the sensitivity of oligonucleotide microarrays. To these ends, we tested these methods on electrochemically interrogated arrays using both purified influenza A PCR products and randomly amplified genomic Francisella tularensis DNA as targets. While SABS treatment did not improve sensitivity for CombiMatrix ElectraSense(?) arrays using purified influenza A cDNA, chip sensitivity was improved 10-fold for randomly amplified targets. SEE improved performance to a greater degree and was able to lower the detection limits 10-fold for influenza A and 100-fold for F. tularensis DNA. These results indicate the promising capability of post-hybridization amplification techniques for enhancing microarray performance.     

Effect of Hydration on Silk Film Material Properties

Effects of hydration on silk fibroin film properties were investigated for water‐annealed and MeOH‐treated samples. Hydration increased thickness by 60% for MeOH‐immersed films, while water‐annealed samples remained constant. MeOH‐immersed films showed an 80% mass loss due to water, while water‐annealed lost only 40%. O₂ permeability was higher in MeOH‐immersed films with Dk values of 10^?10 (mL O₂ · cm) · (cm^?1 · s^?1 · mmHg^?1), while those of water‐annealed films reached only one fifth of this value. All films showed a decrease in Young's modulus and increased plastic deformation by two orders of magnitude when submerged in saline solution. FT‐IR showed that β‐sheet content in water‐annealed films increased with increasing water vapor pressure, while MeOH‐immersed films showed no change.

     

Improving IRMPD in a quadrupole ion trap

A focused laser is used to make infrared multiphoton photodissociation (IRMPD) more efficient in a quadrupole ion trap mass spectrometer. Efficient (up to 100%) dissociation at the standard operating pressure of 1 × 10⁻³ Torr can be achieved without any supplemental ion activation and with shorter irradiation times. The axial amplitudes of trapped ion clouds are measured using laser tomography. Laser flux on the ion cloud is increased six times by focusing the laser so that the beam waist approximates the ion cloud size. Unmodified peptide ions from 200 Da to 3 kDa are completely dissociated in 2.5–10 ms at a bath gas pressure of 3.3 × 10⁻⁴ Torr and in 3–25 ms at 1.0 × 10⁻³ Torr. Sequential dissociation of product ions is increased by focusing the laser and by operating at an increased bath gas pressure to minimize the size of the ion cloud.     

Phenyl-type and C1 stationary phases for environmentally friendlier chromatography

C1 and phenyl-type stationary phases were assessed in terms of their environmental impact on separations using as test solutes polycyclic aromatic hydrocarbons. Methanol (MeOH) and acetonitrile (ACN) mobile-phase gradients were employed. These stationary phases were examined to determine if different physical and chemical properties possessed by these surfaces decreased the organic solvent consumption, and yet maintained peak capacity. The cumulative energy demand (CED) was used to gauge the environmental impact of the separations. The separation of the polycyclic aromatic hydrocarbon test mixture using current methodologies (i.e. a C18/ACN combination) had a CED of 1.13 MJ-eq, and a peak capacity of 27 peaks (resolving 7 of 12 peak pairs with R_s>1). In comparison, a butyl phenyl stationary phase with a methanol mobile phase had a peak capacity of 26, but with a CED of 0.670 MJ-eq. Monolithic columns containing C18 and C1 phases were also tested. A monolithic C18 column with MeOH had the lowest CED at 0.675 MJ-eq, a peak capacity of 28 peaks and good resolving power (resolving ten peak pairs with R_s>1), suggesting that this is a viable option with respect to reducing environmental impact for these types of analyses.