Book chapters will be unavailable on Saturday 24th August between 8am-12pm BST. This is for essential maintenance which will provide improved performance going forwards. Please accept our apologies for any inconvenience caused.
To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
This is a copy of the slides presented at the meeting but not formally written up for the volume.
Film growth in pulsed laser deposition (PLD) occurs from the energetic plume of material ejected from a solid target by pulsed laser ablation. The plume consists of a complex mixture of neutral and ionized atoms, molecules, and even small clusters with kinetic energies ranging from thermal to a few hundred eV. The extra kinetic energy provides a transient (nonequilibrium) enhancement of surface mobility and is believed to alter the nucleation and growth of thin films. However, the mechanisms by which the transient mobility enhancement affect the growth kinetics are not well understood. We use time-resolved surface x-ray diffraction (SXRD) measurements with microsecond range resolution to study the role of nonequilibrium processes in PLD of SrTiO3. The use of x-ray diffraction greatly simplifies growth kinetics studies because in the kinematic limit the x-ray intensity changes correspond directly to coverage changes. Rather than using a transport model to fit the data, we instead analyze the intensity transients using an approach that allows direct determination of the transient surface coverages from the diffraction intensities . The initial change in the coverage shows the fraction of the pulse instantaneously forming on each layer, and the time evolution of the coverages shows the amount of material transferred from the top of the islands into the growing layer. This analysis reveals that the energy-enhanced interlayer transport occurs on a time scale of microseconds or less and it dominates layer filling in PLD growth. A much smaller fraction of material, which is governed by the dwell time between successive laser shots is transferred by slow, thermally driven interlayer transport processes.  J.Z. Tischler, Gyula Eres, B.C. Larson, C.M. Rouleau, P. Zschack, and D.H. Lowndes, Phys. Rev. Lett. 96, 226104 (2006).
Characterisation of genetic diversity in a large number of European pig populations has been undertaken with EC support. The populations sampled included local (rare) breeds, national varieties of the major international breeds, commercial lines and the Chinese Meishan breed. A second phase of the project will sample a further 50 Chinese breeds. Neutral genetic markers (AFLP and microsatellites), with individual or bulk typing, were used and compared.
DNA from 59 European pig populations was extracted on samples of about 50 individuals per population. Individuals were typed for 50 microsatellites and for 148 AFLP bands. A subset of 25 populations was typed for 20 microsatellites on pools of DNA. Allele frequencies were estimated by direct allele counting for the co-dominant markers. Frequencies of AFLP negative alleles (absent bands) were obtained by taking the square root of absent band frequencies. Within-breed variability was summarised using standard statistics: expected and observed heterozygosity, mean observed and effective numbers of alleles, and F statistics. Between-breed diversity analysis was based on a bootstrapped Neighbor-Joining (NJ) tree derived from Reynolds distances (DR). The standard distance of Nei (DS) was also calculated.
Adipose tissue becomes more saturated and less unsaturated with age (Kemp et al., 1981). Desaturation of stearic acid to the oleic acid is catalysed by stearoyl-CoA desaturase (SCD) and increasing the degree of desaturation of lamb is likely to be beneficial in terms of human nutrition. By altering the levels of ovine SCD mRNA, the supply of oleic acid to the tissue could be manipulated, resulting in a practical method of changing the fatty acid profile of the animals meat. Previous work in our laboratory has shown variability between adipose tissue depots in their expression of SCD and that this variability is associated with changes in oleic acid content (Daniel et al, 2004). Such differences in SCD expression between depots implies that there may be even larger variation in SCD expression between breeds. A sheep breed with particularly high level of SCD mRNA could then be exploited through breeding programmes to produce animals with increased desaturase activity and therefore increased oleic acid content. Three sheep breeds, Texel, Beulah and Soay, were therefore used to study the influence of breed and age on SCD expression.
Rapeseed meal is a common protein supplement in ruminant diets that is characterized by high rumen protein degradability (Bertilsson et al., 1994; Vanhatalo et al., 1995). Appropriate treatment can however reduce ruminal protein degradability and increase the efficiency of protein utilization. RaPass (UM Feeds Marketing, Burton on Trent, Staffs, UK) is a commercial rapeseed meal product that made using the Maillard reaction. This is the non-enzymatic browning reaction between proteins and reducing sugars that protects protein from rumen degradation. Release of the protein at abomasal pH allows the peptide chains to be digested at an efficiency similar to that of untreated rapeseed meal (Moss et al 2000). Cows fed rapeseed meal that was treated to increase the rumen undegradable protein (RUP) content have been reported to perform better than those fed untreated rapeseed meal (Bertilsson et al., 1994). This study evaluated the potential of using RaPass as a protein supplement in dairy cow rations.
Objectives: The present study constitutes the first randomized controlled trial to investigate the relation of lutein (L) and zeaxanthin (Z) to brain function using functional magnetic resonance imaging (fMRI). It was hypothesized that L and Z supplementation in older adults would enhance neural efficiency (i.e., reduce activation) and cognitive performance on a verbal learning task relative to placebo. Methods: A total of 44 community-dwelling older adults (mean age=72 years) were randomly assigned to receive either placebo or L+Z supplementation (12 mg/daily) for 1 year. Neurocognitive performance was assessed at baseline and post-intervention on an fMRI-adapted task involving learning and recalling word pairs. Imaging contrasts of blood-oxygen-level-dependent (BOLD) signal were created by subtracting active control trials from learning and recall trials. A flexible factorial model was employed to investigate the expected group (placebo vs. supplement) by time (baseline vs. post-intervention) interaction in pre-specified regions-of-interest. Results: L and Z appeared to buffer cognitive decline on the verbal learning task (Cohen’s d=.84). Significant interactions during learning were observed in left dorsolateral prefrontal cortex and anterior cingulate cortex (p < .05, family-wise-error corrected). However, these effects were in the direction of increased rather than decreased BOLD signal. Although the omnibus interaction was not significant during recall, within-group contrasts revealed significant increases in left prefrontal activation in the supplement group only. Conclusions: L and Z supplementation appears to benefit neurocognitive function by enhancing cerebral perfusion, even if consumed for a discrete period of time in late life. (JINS, 2018, 24, 77–90)
The radiocarbon dating of volcanic ash (tephra) deposits in New Zealand has been difficult on sites remote from the eruption, which contain either little carbon or degraded and contaminated charcoal. Although many studies of contamination removal from macroscopic charcoals from tephra sequences have been made, little attention has been paid to those containing no visible charcoal, because of the difficulty of obtaining sufficient carbon for radiometric dating. We report here experiments using accelerator mass spectrometry to establish a reliable method for dating a low-carbon aeolian and peat deposit containing a tephra horizon. Results so far demonstrate that improvements to existing chemical pretreatment methods are possible, and that dates obtained on oxidized fine-grained residues can approach the maximum age determined on good quality charred wood samples.
To test modifications to nutrition label serving size information on understanding of energy (calorie) content among youth and young adults.
Participants completed two online experiments. First, participants were randomly assigned to view a beverage nutrition label with a reference amount of per serving (250 ml), per container (473 ml) or a dual-column format with both reference amounts. Participants were then randomized to view a cracker nutrition label which specified a single serving in small font, a single serving in large font, or the number of servings per bag with single serving information below. In both experiments, participants estimated energy content. Logistic regression analysis modelled correct energy estimation. Finally, participants reported their preference for serving size display format.
Canadian youth and young adults (n 2008; aged 16–24 years).
In experiment 1, participants randomized to view the nutrition label with per container or dual column were more likely to correctly identify energy content than those using per serving information (P<0·01). For experiment 2, the serving size display format had no association with correct energy estimation. The majority of participants (61·9 %) preferred the serving size format that included servings per package.
Labelling foods with nutrition information using a serving size reference amount for the entire container increased understanding of energy content. Consumers prefer nutrition labels that include more prominently featured serving size information. Additional modifications that further improve consumers’ accuracy should be examined. These results have direct implications for nutrition labelling policy.
Sudden release of accreted ice in fuel systems could pose a serious challenge in aircraft operation. The resultant snowshower may reach the filter and fuel-oil heat exchanger, causing a restriction in fuel flow to the engine. It is fundamental to have an appreciation of the character and the interface shear strength of the accreted ice in aircraft fuel systems. This helps to recognise factors for the sudden release of the accreted ice and the intensity of the consequential snowshower. An experimental study was carried out to quantify the character and the interface shear strength of accreted ice on subcooled surfaces submerged in jet fuel. Ice was accreted on naked aluminium, painted aluminium and carbon fibre composite surfaces at various subcooled temperatures. The accreted ice was akin to fresh snow and exhibited soft and fluffy attributes. The character may be expressed quantitatively in terms of the porosity and was found to be c. 0·95. The ice weakly adhered to the substrate surfaces, and the interface shear strength was found to be c. 0·36Pa and c. 2·19Pa at the top surface and at the vertical surface of a specimen block, respectively. It was not possible to detect any variation in the porosity and the interface shear strength for different types of surface finishes and differences in water affnity in fuels due to the crude approach in the estimation of these parameters.
The Ki-67 proliferative index has become a useful, objective, immunohistochemical tool that can aid in grading and prognostication for patients with oligodendrogliomas. Previous studies have described the prognostic significance of the Ki-67 index for such patients.
According to the WHO classification of tumors of the central nervous system (2007) ”mitotic activity is low in WHO grade II oligodendroglioma, and labeling indices for proliferation markers are accordingly low, usually below 5%”. Furthermore, the predictive value of the Ki-67 index appears to be independent of age, tumor site, and histological grade. What is less well described is the relative accuracy of traditional vs. semi-automated methods of enumeration for a test where small differences can influence grading, prognosis and treatment. Tang et al. (2012), studying gastroenteropancreatic neuroendocrine tumours, found high concordance between two semi-automated methods for Ki-67 quantitation whereas “eyeballed estimates” were far less reliable. We will compare the reported proliferative index estimates to those calculated by digital image analysis of 35 recent oligodendrogliomas from the LHSC Pathology archives.
To assess understanding of the Department of Health weaning guidelines and weaning influences in a self-selected sample of black and minority ethnic (BME) parents, residing in London.
A face-to-face, questionnaire-facilitated survey among Black African, Black Caribbean and South Asian parents.
An opportunistic sample of parents was recruited from Sure Start centres, churches and play groups across key London boroughs.
Three hundred and forty-nine interviews were included; 107 Black African, fifty-four Black Caribbean, 120 South Asian and sixty-four of Black mixed-race ethnicity.
Fifty-two per cent of Black and 66 % of South Asian parents had accurate understanding of the guidelines. Inaccurate knowledge of the guidelines was associated with weaning before 17 weeks (P < 0·001); 36 % of Black Africans and 31 % of Black Caribbeans were weaned before 4 months compared with 16 % of South Asians. All BME groups were most influenced by weaning information from the previous generations of mothers in their families, which was associated with earlier weaning (21·5 (sd 6·5) v. 24·1 (sd 4·2) weeks; F(2,328) = 5·79, P = 0·003), and less so by professional infant feeding advice, which was associated with a later weaning age (23·7 (sd 5·1) v. 20·7 (sd 5·7) weeks; F(1,344) = 34·7, P < 0·001).
Lack of awareness of the Department of Health weaning guidelines is common among these BME populations, whose weaning behaviour is strongly influenced by informal advice. Further research is necessary to elucidate the influences on weaning in these populations and to facilitate the development of infant feeding support which is salient for BME groups in the UK.
About a thousand optical absorption features on the interstellar extinction curve popularly known as the Diffuse Interstellar Bands (DIBs) have been observed. The numbers are increasing every year, thanks to the improvement in telescope and spectroscopic technology. Ultra-high resolution spectroscopic observations and emission features corresponding to some of the DIBs suggest that, some if not all, of these features are due to large molecules. The strength of DIBs depend on the amount of reddening which is directly proportional to the amount of material present between the background star and the observer. Since, the strengths of the DIBs are not strongly correlated with each other, there must be several carriers. Time Dependent Density Functional Theory (TDDFT) calculations are useful in narrowing down molecular systems that may be further investigated in the laboratory.
The observations of the unidentified infrared (UIR) bands point towards the widespread presence of Polycyclic Aromatic Hydrocarbon (PAH) molecules. Though, not a single PAH has been discovered in interstellar space, these are the largest molecules suspected to be present. PAHs are stable towards energetic environment prevailing under interstellar conditions rendering these molecules to be good candidates as DIB carriers. We report TDDFT calculations to predict electronic transitions of neutral, protonated-deuteronated and PAHs with five member rings with various sites of protonation and deuteronation. Compared to their neutral forms, these charged isoelectronic forms of PAHs are predicted to have active transitions in the visible region, which means they are suitable candidates as carriers for some of the DIBs and laboratory studies are warranted for these systems.
We report on high quality Ba1−xKxBiO3 (BKBO) thin films grown by pulsed laser deposition. The best films exhibit resistive and magnetic transition temperatures of 28 K, with a transition width of 0.4 K and critical current densities above 106 A/cm2 measured at 5 K. Surface impedance is measured to be 1 mΩ. Films are single phase and highly oriented in the (100) direction and electron diffraction shows no other phases. Analysis using Moire' fringes shows films to consist of 100 nm size dislocation-free regions which show a high degree of in-plane epitaxy.
Use of a Fourier—transform interferometer integrated with a variable incidence angle ellipsometer extends the spectral range and the capabilities of spectroscopic ellipsometry into the infrared. With a spectral range of 600 to 6600 cm—1, thick layers, such as epitaxial doped layers and polymers can be analysed.
A full description of this novel instrument will be given. Incidence angle can be variedautomatically to enhance signal/noise and the ellipsometric data can be obtained together with vibrational absorption bands information to give a characteristic “fingerprint ” of the layers.
Examples of spectra of HCN polymer on nickel, DMHS on aluminium and PMMA on silicon willbe presented for various incidence angles and layer thickness.
Measurements were made of the conductance of single crystal Au-doped Si and silicon-on-sapphire (SOS) during irradiation with 30 nsec ruby laser pulses. After the decay of the photoconductive response, the sample conductance is determined primarily by the thickness and conductivity of the molten layer. For the single crystal Au-doped Si, the solid-liquid interface velocity during recrystallization was determined from the current transient to be 2.5 m/sec for energy densities between 1.9 and 2.6 J/cm2, in close agreement with numerical simulations based on a thermal model of heat flow. SOS samples showed a strongly reduced photoconductive response, allowing the melt front to be observed also. For complete melting of a 0.4 μm Si layer, the regrowth velocity was 2.4 m/sec.
The goal of the project was to determine whether PDAC (poly (diallyldimethylammonium chloride), also abbreviated PDADMAC) could be printed reproducibly to create patterns with a sub-micron resolution. PDAC was stamped onto bare silicon using PDMS stamps having features only about 150 nm wide. A variety of aqueous PDAC inks were tried, to study the effect of concentration and ionic strength on the pattern produced. In order to get good prints, new stamping techniques were also required. A rigid stamping apparatus was built to ensure steady placement, and the stamps were spin coated with a different ink solution to produce thin, even coats of ink.  Using these methods, the pattern transferred.
Members of the Ruddlesden-Popper system, La2Ni(1-x)CoxO4+δ (0.00 ≤ × ≤ 1.00), were synthesized and studied for their potential use as cathodes for solid-oxide fuel cells. An unusual structural trend has been noted across the series, which appears to correlate with the oxygen-hyperstoichiometry observed. Details of the structural variance by x-ray and neutron diffraction, as well as selected physical properties for this system will be presented.
In-plane aligned MgO thin films (∼100Å) have been obtained on various amorphous substrates by Ar+ ion-assisted electron-beam evaporation. Based on RHEED and cross-section TEM, we have shown that the MgO texture appears at a very early stage of film growth and is optimized at a thickness of around 100Å. Optimal thickness is the stage at which the surface is fully covered by MgO crystallites. The planar-view TEM of grain structure evolution in samples at different stages of growth reveals the dynamics of the texture developing process. Small, (100)-faceted MgO grains were observed both in planar-view and cross-section TEM images.