Diet modifies the risk of colorectal cancer (CRC), and inconclusive evidence suggests that yogurt may protect against CRC. We analysed the data collected from two separate colonoscopy-based case–control studies. The Tennessee Colorectal Polyp Study (TCPS) and Johns Hopkins Biofilm Study included 5446 and 1061 participants, respectively, diagnosed with hyperplastic polyp (HP), sessile serrated polyp, adenomatous polyp (AP) or without any polyps. Multinomial logistic regression models were used to derive OR and 95 % CI to evaluate comparisons between cases and polyp-free controls and case–case comparisons between different polyp types. We evaluated the association between frequency of yogurt intake and probiotic use with the diagnosis of colorectal polyps. In the TCPS, daily yogurt intake v. no/rare intake was associated with decreased odds of HP (OR 0·54; 95 % CI 0·31, 0·95) and weekly yogurt intake was associated with decreased odds of AP among women (OR 0·73; 95 % CI 0·55, 0·98). In the Biofilm Study, both weekly yogurt intake and probiotic use were associated with a non-significant reduction in odds of overall AP (OR 0·75; 95 % CI 0·54, 1·04) and (OR 0·72; 95 % CI 0·49, 1·06) in comparison with no use, respectively. In summary, yogurt intake may be associated with decreased odds of HP and AP and probiotic use may be associated with decreased odds of AP. Further prospective studies are needed to verify these associations.

We report on the analysis of virtual powder-diffraction patterns from serial femtosecond crystallography (SFX) data collected at an X-ray free-electron laser. Different approaches to binning and normalizing these patterns are discussed with respect to the microstructural characteristics which each highlights. Analysis of SFX data from a powder of Pr0.5Ca0.5MnO3 in this way finds evidence of other trace phases in its microstructure which was not detectable in a standard powder-diffraction measurement. Furthermore, a comparison between two virtual powder pattern integration strategies is shown to yield different diffraction peak broadening, indicating sensitivity to different types of microstrain. This paper is a first step in developing new data analysis methods for microstructure characterization from serial crystallography data.

A transmission electron microscope (TEM) is much more than just a tool for imaging the static state of materials. To demonstrate this, we present work on studying the mechanical and electrical properties of carbon nanotube devices. Multiwall carbon nanotubes are concentrically stacked tubular sheets of graphite, where the spacing between each cylinder is simply the natural spacing of graphite. Using a custom-built in-situ nanomanipulation probe, we have shown that it is possible to slide the nanotube layers in a telescopic extension mode that exhibits low friction, demonstrating the potential of nanotubes as the ultimate synthetic nanobearing. During this telescopic extension, the electrical resistance of the nanotube devices increases, opening the possibility that these devices can also be used as nanoscale rheostats. We also briefly describe work on using electron holography inside a TEM to study the electric field distribution in nanotube field-emission devices and on using a nanotube itself as a biprism for electron holography. These measurements together demonstrate the wealth of information that can be obtained and frontiers that can be opened by putting operational nanodevices inside an electron microscope.

Microstructures of La1-xCaxMnO3 compounds (x = ⅓ and 0.5) prepared with and without intermediate grinding were studied using transmission electron microscopy. A high density of antiphase boundaries (APBs) with displacement vector 1/2 〈111〉, indexed in orthorhombic unit cell, has been observed in bulk samples with no or minimum intermediate grinding. The nature of this APB is analyzed and found to bedue to the symmetry breaking introduced by the tilting of MnO6 octahedra relative to the ideal perovskite structure. Samples prepared using two intermediate grinds do not show these defects indicating that the microstructure can be controlled through synthesis routes. The effect of domain boundaries on the colossal magnetoresistance effect is discussed.

The ABA-1 protein of Ascaris lumbricoides (of humans) and Ascaris suum (of pigs) is abundant in the pseudocoelomic fluid of the parasites and also appears to be released by the tissue-parasitic larvae and the adult stages. The genes encoding the polyprotein precursor of ABA-1 (aba-1) were found to be arranged similarly in the two taxa, comprising tandemly repeating units encoding a large polyprotein which is cleaved to yield polypeptides of approximately 15 kDa which fall into 2 distinct classes, types A and B. The polyprotein possibly comprises only 10 units. The aba-1 gene of A. lumbricoides is polymorphic, and the majority of substitutions observed occur in or near predicted loop regions in the encoded proteins. mRNA for ABA-1 is present in infective larvae within the egg, and in all parasitic stages, but was not detectable in unembryonated eggs. ABA-1 mRNA was confined to the gut of adult parasites, and not in body wall or reproductive tissues. Recombinant protein representing a single A-type unit for the A. lumbricoides aba-1 gene was produced and found to bind retinol (Vitamin A) and a range of fatty acids, including the pharmacologically active lipids lysophosphatidic acid, lysoplatelet activating factor, and there was also evidence of binding to leukotrienes. It failed to bind to any of the anthelmintics screened. Differential Scanning Calorimetry showed that the recombinant protein was highly stable, and unfolded in a single transition at 90·4 °C. Analysis of the transition indicated that the protein occurs as a dimer and that the dimer dissociates simultaneously with the unfolding of the monomer units.

The results of recent ab-initio, relaxed, computations for the energy barrier to the motion of a kink on a 30° partial dislocation in silicon are summarised. The electronic structure and charge density are given. We suggest that the shearing motions involved with ductility and kink motion are controlled by the band structure energy involving valence electrons, whereas the tensile forces involved in fracture depend on both ion-ion and valence forces. Experimental atomic resolution TEM images of dissociated dislocation lines in silicon are discussed. These are formed using “forbidden reflections” with the dislocation lines lying on (111), normal to the electron beam. For images of samples at 600 C recorded at video rates, differences between successive frames reveal the motion of individual kinks, from which the kink velocity and migration energy can be estimated.

The growth mechanism for small precipitates of Al2O3 formed by internal oxidation in the Nb–Al2O3 interface is studied in detail. The observations show that the Nb (001)/Al2O3 (00.1) interface is almost atomically flat and that there are no interface compounds. We suggest that the final layer on the Al2O3 side of this interface consists of oxygen atoms. The effects of image forces on misfit dislocations are found to result in a standoff distance between dislocation cores and the interface, in good agreement with the recent theory. The implications of this for the strength of metal-ceramic bonding are discussed.

In this paper we report the first observations by cathodoluminescence in TEM of radiative infrared emission from dislocations in silicon. These results were obtained at 23-25K in a Philips EM400 electron microscope. Our results are interpreted in the light of earlier photoluminescence work, and the prospects for obtaining spectra from a small number of well characterized dislocations with high spatial resolution are reviewed. Preliminary results are also reported showing the infrared band-gap emission spectrum of GaInAs at 90K recorded using a small Fourier Transform Spectrometer fitted to the same electron microscope. Finally, we describe timing coincidence experiments from samples in which only those visible CL photons are counted which arrive at the detector at the same time as the corresponding transmitted electron energy loss event. We describe the use of this technique for life-time mapping in semiconductors.

1.1. The work for the paper was carried out by the authors as members of the Bonus and Valuation Research Group of the Faculty of Actuaries. The previous paper produced as a result of work done in the Bonus Research Group (Studies of Reversionary Bonus using a Model Office, TFA 37, 91) used a deterministic model office. Future interest rates and returns from equity investment were assumed known and the effects on reversionary bonus of variations in the valuation bases, rates of expansion and inflation of expenses were examined. The assumption of an exact knowledge of future investment returns was a great simplification and begged many of the important questions facing a life office actuary. In this paper the Research Group has paid attention to the change in the value of the assets under variations in financial conditions.

Evidence for a new microcrystalline precipitate in CZ Si annealed for 256 hrs at 635°C is presented by electron microdiffraction. This may be a precursor phase for the formation of amorphous platelets [9]. Multiple scattering microdiffraction calculations which distinguish the symmetries of two models for the thermal donor are also given.

Recent applications of the “Atom Location by Channelling Enhanced Microanalysis” (ALCHEMI) are summarised. This is a quantitative method for determining the sites of impurity atoms in crystals using an electron microscope and X-ray analysis system. Since the fractional site occupancies are given in terms of measured X-ray counts alone, it involves no adjustable parameters. New experiments have been performed on the temperature dependence of characteristic X-ray production under channelling conditions for InP and GaAs. We conclude that low temperatures will give more accurate results for “ALCHEMI” in some materials due to the reduction in diffuse inelastic phonon scattering, and that the study of this temperature dependence may provide new information from small areas or particles on the correlations amongst atom motions due to thermal vibration.

Ohmic contacts to GaAs have been studied using a high resolution TEM, an SEM and a STEM with an energy dispersive x-ray attachment. Two different deposition sequences of the constituent Au-Ge-Ni metals yielded specific contact resistivities that varied by one order of magnitude. Crosssection images of the interface between the GaAs and the metal Au-Ge-Ni layers following alloying showed protrusions at the interface. Contacts with low specific resistivities showed deeper protrusion and also significantly more Ge and Ni in the GaAs.