Food texture and food intake : the role of oral sensory exposure

Background and objective: In view of the growing epidemic of obesity, it is important to investigate factors which influence food intake. Food texture has been shown to play a role in food intake regulation but underlying explaining mechanisms are unknown. The aim of this thesis was to determine the effect of food texture on satiation (assessed as ad libitum food intake) and to investigate the mediating role of oral sensory exposure and gastro-intestinal physiology in this effect. Methods: We started by investigating the effect of food viscosity on ad libitum food intake (n=108). Next, we investigated whether the effect of viscosity could be related to eating effort and/or eating rate (n=49) or to the release of the gastro-intestinal hormones ghrelin, CCK and GLP-1 (n=33). To further explore the role of oral sensory exposure, we investigated the effect of changing bite size and oral processing time of a semi-solid food on satiation (n=22), and the effect of changing food texture of three pairs of solid foods on satiation (n=106). Finally, we observed eating behavior and retro-nasal aroma release in normal weight and overweight subjects (n=54). Results: Viscosity of food had a clear effect on food intake; increasing viscosity significantly decreased ad libitum food intake and the difference in intake between the liquid and semi-solid product ranged from 29% to 34% in different settings. Eating rate played an important role; the liquid product was consumed significantly faster than the semi-solid product and a standardized eating rate led to similar intakes of these products. The selected gastro-intestinal hormones could not explain the effect of viscosity on food intake; a fixed amount of the liquid and semi-solid test product resulted in a similar response of the hormones. Food intake of a semi-solid food was significantly less when oral processing time was fixed to 9 s compared to 3 s (on average a difference of 42 g) and when consumed with fixed small bite sizes (≈ 5 g) compared to large bite sizes (≈ 15 g) (on average a difference of 106 g). Differences in food texture of solid foods, aimed to change oral processing time, did not affect food intake. Texture differences were probably too subtle to lead to differences in eating rate and subsequently to differences in food intake. Significant positive associations between food intake and eating behaviors such as eating rate and bite size were observed. Small to no differences in eating behavior and retro-nasal aroma release were found between normal weight and overweight subjects. Conclusion: The results of this thesis show that food viscosity has a direct effect on food intake. Oral sensory exposure plays a major role in this since changing eating rate, oral processing time and bite size affected food intake. These factors contribute to the effect of food texture on food intake. In addition, eating rate and bite size were characteristics of the eating style of an individual. <br/

Epitaxial aluminium-nitride tunnel barriers grown by nitridation with a plasma source

High critical current-density (10 to 420 kA/cm^2) superconductor-insulator-superconductor tunnel junctions with aluminium nitride barriers have been realized using a remote nitrogen plasma from an inductively coupled plasma source operated in a pressure range of 10^{-3} to 10^{-1} mbar. We find a much better reproducibility and control compared to previous work. From the current-voltage characteristics and cross-sectional TEM images it is inferred that, compared to the commonly used AlO_x barriers, the poly-crystalline AlN barriers are much more uniform in transmissivity, leading to a better quality at high critical current-densities.Comment: 3 pages, 3 figures, accepted for publication in AP

Reduced frequency noise in superconducting resonators

We report a reduction of the frequency noise in coplanar waveguide superconducting resonators. The reduction of 7 dB is achieved by removing the exposed dielectric substrate surface from the region with high electric fields and by using NbTiN. In a model-analysis the surface of NbTiN is found to be a negligible source of noise, experimentally supported by a comparison with NbTiN on SiOx resonators. The reduction is additive to decreasing the noise by widening the resonators.Comment: 4 pages, 4 figure

The Local Group Census: planetary nebulae in Sextans B

Five planetary nebulae (PNe) have been discovered in the nearby dwarf irregular galaxy. Emission line images were obtained using the Wide Field Camera of the 2.5m Isaac Newton Telescope (INT) at La Palma (Spain). The candidate PNe were identified by their point-like appearance and relatively strong [OIII] emission-line fluxes. They are located within a galactocentric distance of 2.8 arcmin, corresponding to 1.1 kpc at the distance of Sextans B. Luminosities are in the range 1800--5600Lsolar. Sextans B is one of the smallest dwarf irregular galaxies with a PN population. The number of PNe detected suggest an enhanced star formation rate between 1 and 5 Gyr ago.Comment: 7 pages, 2 figure

Preferential uptake of the non steroid anti-inflammatory drug diclofenac into inflamed tissues after a single oral dose in rats

BACKGROUND: Diclofenac is a nonsteroidal anti-inflammatory drug which is available as prescription (RX) and over-the-counter (OTC) medication for the systemic and topical treatment of painful and inflammatory conditions such as arthritis and back pain. This study was undertaken to investigate the distribution and retention of diclofenac and/or its metabolites in inflamed tissues, using the carrageenan-induced inflammation model and quantitative whole body autoradiography in rats. METHODS: [14C]diclofenac sodium was administrated as a single 2 mg/kg oral dose 1 h after injection of carrageenan into one front and one hind footpads and subcutaneously into the dorsum of the neck of rats. A control animal received saline injections. Three carrageenan-treated rats and one control rat were sacrificed at 1, 4, 8, and 24 h after [14C]diclofenac sodium administration (total of 4 rats/time point). The carcasses were immediately snap-frozen and prepared for cryosectioning. Lengthwise whole-body sections (40 microm thick), including all major tissues, were obtained from different levels across the body. The tissue concentrations of total radiolabeled components were determined using quantitative autoradioluminography. RESULTS: The radioactivity patterns demonstrated that diclofenac and/or its metabolites preferentially distributed into the inflamed tissues. In unharmed tissues the distribution was similar in control and treated animals. The exposure, based on the areas under the tissue concentration versus time (AUC(0-tlast)), was 26 and 53 fold higher in the inflamed neck and inflamed footpads of treated animals than in control rats; the exposures in unharmed tissues were similar in the treated and control rats, and the AUC(0-tlast) was 17 fold higher in the inflamed paws than in the non inflamed footpads of the carrageenan-treated rats. The higher exposure in the inflamed tissues may be explained partly to the fact that the elimination of total radiolabeled components from inflamed tissues (t(1/2) = 6 h) appeared lower than from the corresponding unharmed tissues (t(1/2) = 2 h). CONCLUSION: This animal study demonstrated that diclofenac and/or its metabolites were rapidly and preferentially taken up and retained in inflamed tissues. Although there were theoretical considerations that mildly acidic NSAID may show some preferential distribution in inflamed tissues there was no clear experimental proof for diclofenac until the present study

A study of rotating globular clusters - the case of the old, metal-poor globular cluster NGC 4372

Aims: We present the first in-depth study of the kinematic properties and derive the structural parameters of NGC 4372 based on the fit of a Plummer profile and a rotating, physical model. We explore the link between internal rotation to different cluster properties and together with similar studies of more GCs, we put these in the context of globular cluster formation and evolution. Methods: We present radial velocities for 131 cluster member stars measured from high-resolution FLAMES/GIRAFFE observations. Their membership to the GC is additionally confirmed from precise metallicity estimates. Using this kinematic data set we build a velocity dispersion profile and a systemic rotation curve. Additionally, we obtain an elliptical number density profile of NGC 4372 based on optical images using a MCMC fitting algorithm. From this we derive the cluster's half-light radius and ellipticity as r_h=3.4'+/-0.04' and e=0.08+/-0.01. Finally, we give a physical interpretation of the observed morphological and kinematic properties of this GC by fitting an axisymmetric, differentially rotating, dynamical model. Results: Our results show that NGC 4372 has an unusually high ratio of rotation amplitude to velocity dispersion (1.2 vs. 4.5 km/s) for its metallicity. This, however, puts it in line with two other exceptional, very metal-poor GCs - M 15 and NGC 4590. We also find a mild flattening of NGC 4372 in the direction of its rotation. Given its old age, this suggests that the flattening is indeed caused by the systemic rotation rather than tidal interactions with the Galaxy. Additionally, we estimate the dynamical mass of the GC M_dyn=2.0+/-0.5 x 10^5 M_Sun based on the dynamical model, which constrains the mass-to-light ratio of NGC 4372 between 1.4 and 2.3 M_Sun/L_Sun, representative of an old, purely stellar population.Comment: Accepted for publication in A&A, 12 pages, 14 figures, 2 table

Submillimeter polarisation and magnetic field properties in the envelopes of proto-planetary nebulae CRL 618 and OH 231.8+4.2

We have carried out continuum and line polarisation observations of two Proto-planetary nebulae (PPNe), CRL 618 and OH 231.8+4.2, using the Submillimeter Array (SMA) in its compact configuration. The frequency range of observations, 330-345 GHz, includes the CO(J=3-2) line emission. CRL 618 and OH 231.8+4.2 show quadrupolar and bipolar optical lobes, respectively, surrounded by a dusty envelope reminiscent of their AGB phase. We report a detection of dust continuum polarised emission in both PPNe above 4 sigma but no molecular line polarisation detection above a 3 sigma limit. OH 231.8+4.2 is slightly more polarised on average than CRL 618 with a mean fractional polarisation of 4.3 and 0.3 per cent, respectively. This agrees with the previous finding that silicate dust shows higher polarisation than carbonaceous dust. In both objects, an anti-correlation between the fractional polarisation and the intensity is observed. Neither PPNe show a well defined toroidal equatorial field, rather the field is generally well aligned and organised along the polar direction. This is clearly seen in CRL 618 while in the case of OH 231.8+4.2, the geometry indicates an X-shaped structure coinciding overall with a dipole/polar configuration. However in the later case, the presence of a fragmented and weak toroidal field should not be discarded. Finally, in both PPNe, we observed that the well organised magnetic field is parallel with the major axis of the 12CO outflow. This alignment could indicate the presence of a magnetic outflow launching mechanism. Based on our new high resolution data we propose two scenarios to explain the evolution of the magnetic field in evolved stars.Comment: 11 pages, 8 figures and 1 table. Accepted for publication in the Monthly Notices of the Royal Astronomical Societ

The massive expanding molecular torus in the planetary nebula NGC 6302

We measure the mass and kinematics of the massive molecular torus in the planetary nebula NGC 6302. The nebula is the proto-typical butterfly nebula. The origin of the wing-like morphology is disputed: determining the mass-loss history of the confining torus is an important step in understanding the formation of this structure. We performed submillimeter observations with JCMT and the SMA interferometer. The continuum emission as well as the J=2-1 and 3-2 transitions of 12CO and 13CO are analysed at arcsecond resolution. The CO emission indicates a mass of the torus of ~ 2Msun +/- 1Msun. The 12CO and 13CO emission matches the dark lane seen in absorption in the Halpha image of the object. The CO torus is expanding with a velocity of ~ 8 km/s, centred at Vlsr=-31.5 km/s. The size and expansion velocity of the torus indicates that the torus was ejected from ~ 7500 yr to 2900 yr ago, with a mass-loss rate of 5x10^{-4}Msun/yr. We also see a ballistic component in the CO images with a velocity gradient of 140 km/s/pc. The derived mass-loss history of the torus favours binary interaction as the cause of the ejection of the torus. We predict the existence of a companion with an orbital period P < 1 month.Comment: 13 pages, 10 figures, accepted for publication in A&

The metallicity extremes of the Sagittarius dSph using SALT spectroscopy of PNe

In this work we present the first spectroscopic results obtained with the Southern African Large Telescope (SALT) telescope during its perfomance-verification phase. We find that the Sagittarius dwarf spheroidal galaxy (Sgr) Sgr contains a youngest stellar population with [O/H] -0.2 and age t>1 Gyr, and an oldest population with [O/H]=-2.0. The values are based on spectra of two planetary nebulae (PNe), using empirical abundance determinations. We calculated abundances for O, N, Ne, Ar, S, Cl, Fe, C and He. We confirm the high abundances of PN StWr2-21 with 12+log(O/H) = 8.57+/-0.02 dex. The other PN studied, BoBn1, is an extraordinary object in that the neon abundance exceeds that of oxygen. The abundances of S, Ar and Cl in BoBn1 yield the original stellar metallicity, corresponding to 12+log(O/H) = 6.72+/-0.16 dex which is 1/110 of the solar value. The actual [O/H] is much higher: third dredge-up enriched the material by a factor of ~12 in oxygen, ~240 in nitrogen and ~70 in neon. Neon as well as nitrogen and oxygen content may have been produced in the intershell of low-mass AGB stars. Well defined broad WR lines are present in the spectrum of StWr2-21 and absent in the spectrum of BoBn1. This puts the fraction of [WR]-type central PNe stars to 67% for dSph galaxies.Comment: 14 pages, 4 figures, accepted to MNRA

Food neophobia and mealtime food consumption in 4-5 year old children.

Background: Previous research has documented a negative association between maternal report of child food neophobia and reported frequency of consumption of fruit, vegetables, and meat. This study aimed to establish whether neophobia is associated with lower intake of these food types in naturalistic mealtime situations. Methods: One hundred and nine parents of 4–5 year olds completed questionnaires which included a six-item version of the Child Food Neophobia Scale (CFNS). The children took part in a series of 3 test lunch meals at weekly intervals at school at which they were presented with: chicken, cheese, bread, cheese crackers, chocolate biscuits, grapes and tomatoes or carrot sticks. Food items served to each child were weighed before and after the meal to assess total intake of items in four categories: Fruit and vegetables, Protein foods, Starchy foods and Snack foods. Pearson Product Moment Correlations and independent t tests were performed to examine associations between scores on the CFNS and consumption during lunches. Results: Neophobia was associated with lower consumption of fruit and vegetables, protein foods and total calories, but there was no association with intake of starch or snack foods. Conclusion: These results support previous research that has suggested that neophobia impacts differentially on consumption of different food types. Specifically it appears that children who score highly on the CFNS eat less fruit, vegetables and protein foods than their less neophobic peers. Attempts to increase intake of fruit, vegetables and protein might usefully incorporate strategies known to reduce the neophobic response