Papers by Nicolas Antille
Understanding the regularity and the variability of individual travel behaviour over time has bee... more Understanding the regularity and the variability of individual travel behaviour over time has been one of the key issues in travel behaviour research for three decades. A deeper insight into the long-term mobility patterns of persons and households has been so far restricted by the limited availability of longitudinal data, though.
Nutrients, 2012
Social and psychological stressors are both a part of daily life and are increasingly recognized ... more Social and psychological stressors are both a part of daily life and are increasingly recognized as contributors to individual susceptibility to develop diseases and metabolic disorders. The present study investigated how snacks differing in sensory properties and presentation can influence ratings of affect in consumers with different levels of dispositional anxiety. This study examines the relationships between a pre-disposition to anxiety and food using a repeated exposures design with three interspersed test days over a period of two weeks. The study was conducted on ninety free-living male (n = 28) and female (n = 62) Dutch participants aged between 18 and 35 years old, with a BMI between 18 and 25 kg/m 2 and different anxiety trait levels assessed using State-Trait Anxiety Inventory tests. The study was randomized by age, gender, anxiety trait score, and followed a parallel open design. Three test products: dark chocolate, a milk chocolate snack and crackers with cheese spread (control), which differed in composition, sensory properties and presentation, were evaluated. Changes in self-reported anxiety, emotion, and energetic states were assessed as a function of eating the snacks just after consumption and up to one hour. The repeated exposure design over a period of two weeks enabled the investigations of potential cumulative effects of regular consumption of the food products. The milk chocolate snack resulted in the decrease of anxiety in high anxiety trait subjects, whereas dark chocolate and cheese and crackers respectively improved the anxiety level and the energetic state of low anxiety trait participants. The mood effects were not altered with repeated exposure, and the magnitude
Understanding the regularity and the variability of individual travel behaviour over time has bee... more Understanding the regularity and the variability of individual travel behaviour over time has been one of the key issues in travel behaviour research for three decades. A deeper insight into the long-term mobility patterns of persons and households has been so far restricted by the limited availability of longitudinal data, though. This paper presents an innovative approach to gain longitudinal travel behaviour data by means of Global Positioning Systems (GPS) and furthermore, describes the outline of post-data-processing work as well as possible analysis and modelling directions.
Rapid Communications in Mass Spectrometry
Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) was ap... more Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) was applied to identify markers for cellular differentiation. The differentiation of a human colon epithelial carcinoma T84 cell line was monitored over a period of 28 days by transepithelial electrical resistance (TER) measurements, alkaline phosphatase (AP) assay, and MALDI-TOF mass spectral fingerprints combined with statistical analysis. MALDI-MS generated specific mass spectral fingerprints characteristic of cell differentiation. Twenty-two ions were selected as diagnostic signals of fully differentiated T84 cells. Ten protein ion signals, detected by MALDI-MS and validated by statistical analysis, were proposed as T84 cell differentiation markers. Among these signals, ubiquitin was identified as a T84 cell differentiation marker by nanospray liquid chromatography/tandem mass spectrometry (nanoLC/MS/MS). Moreover, depending on the concentration of the cells seeded on the growth support, i...
Chemosensory Perception, 2009
The present study aimed to compare the accuracy and reliability of four standard methods used for... more The present study aimed to compare the accuracy and reliability of four standard methods used for classification of people as taster or non-tasters based on their sensitivity to PROP (6-n-propylthiouracil). A panel consisting of 21 subjects was tested for threshold and suprathreshold sensitivity of sodium chloride, PROP, and genotyped for TAS2R38. Two threshold methods, staircase and modified Harris-Kalmus, were used to obtain detection and recognition thresholds and compared for accuracy and repeatability. Similarly, two suprathreshold techniques, the just noticeable differences (JND) and the general labeled magnitude scale (gLMS), were used to determine Weber fractions and individual psychophysical functions and compared for accuracy and repeatability. Results show both threshold methods have been able to correctly separate people into two groups of tasters and non-tasters, with the staircase method having a lower variability among subjects. On the suprathreshold front, we found differences in sensitivity between tasters and non-tasters when comparing Weber fractions and psychophysical functions; however, our data suggest that clustering people without previous knowledge of their taster status is less accurate when using Weber fractions. Intensity ratings are more reliable to classify people into tasters and non-tasters. Results show that the staircase for threshold measurement and the gLMS methods are more reliable methods than Harris-Kalmus and JND for phenotyping people and can be used in large-scale studies in the quest to discover new genotype-phenotype associations.
Rapid Communications in Mass Spectrometry, 2008
Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) was ap... more Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) was applied to identify markers for cellular differentiation. The differentiation of a human colon epithelial carcinoma T84 cell line was monitored over a period of 28 days by transepithelial electrical resistance (TER) measurements, alkaline phosphatase (AP) assay, and MALDI-TOF mass spectral fingerprints combined with statistical analysis. MALDI-MS generated specific mass spectral fingerprints characteristic of cell differentiation. Twenty-two ions were selected as diagnostic signals of fully differentiated T84 cells. Ten protein ion signals, detected by MALDI-MS and validated by statistical analysis, were proposed as T84 cell differentiation markers. Among these signals, ubiquitin was identified as a T84 cell differentiation marker by nanospray liquid chromatography/ tandem mass spectrometry (nanoLC/MS/MS). Moreover, depending on the concentration of the cells seeded on the growth support, it was possible to predict the timing of the exponential phase and of cellular differentiation by MALDI-MS-derived marker ions. MALDI-TOFMS was compared to other methods for the determination of cellular differentiation: TER measurements are rapid but yield limited information as to the cellular differentiation state. AP assays are more specific for the differentiation state but take more time. By contrast, MALDI-MS has been found to be a fast, sensitive and precise method for cell differentiation assessment and provides the opportunity for multiplexing and high throughput. Moreover, the consumable costs per assay are very low.
The Journal of Nutrition, 2008
Fructooligosaccharides (FOS) are considered prebiotics because of their ability to promote growth... more Fructooligosaccharides (FOS) are considered prebiotics because of their ability to promote growth of specific beneficial gut bacteria, such as bifidobacteria. Some studies reported potential immune-modulating properties. The aim of this study was to investigate the effect of FOS:inulin mix on murine response to Salmonella vaccine and evaluate the relevance toward protection against Salmonella infection. Balb/c mice were fed a diet containing 5% FOS:inulin mix or a control diet 1 wk before oral immunization with a suboptimal dose of live attenuated Salmonella typhimurium vaccine. Four weeks after vaccination, mice were infected with LD100 of virulent S. typhimurium. Specific blood Salmonella immunoglobulin G and fecal immunoglobulin A significantly increased in mice fed the diet containing prebiotics compared with control mice 4 wk postimmunization. Peritoneal macrophage phagocytic activity also significantly increased in FOS:inulin-fed mice at 1 wk postimmunization compared with control mice. No detectable effects were observed on the percentage of lymphoid cell subsets in the spleen. However, production of cytokines, interferon-g, interleukin-12, and tumor necrosis factor a, was numerically increased in spleen cell cultures stimulated with mitogens from FOS:inulin-fed mice 1 and 4 wk postimmunization. Salmonella translocation to lymphoid organs was not affected by feeding FOS:inulin. However, the improved response to Salmonella vaccine was concomitant with an increase in the survival rate of FOS:inulin-fed mice upon challenge with virulent Salmonella. No detectable effects were observed on the composition or the metabolic activity of the microbiota. Overall, the data suggest that a diet supplemented with FOS:inulin mix stimulates mucosal immunity and seems to improve efficacy of an oral vaccine.
Journal of Agricultural and Food Chemistry, Mar 1, 2008
Lipids between the tongue and palate strongly contribute to the sensory impact of a product. Mout... more Lipids between the tongue and palate strongly contribute to the sensory impact of a product. Mouthfeel is a sensory attribute responsible for distinguishing reduced fat from full fat food products. The aim of this work was to quantify the distribution, deposition, and retention of lipids on the tongue and palate upon oral processing and relate this to texture. The thickness of lipid deposition was measured in mouth by fluorescence. A trained panel evaluated the perceived intensity of samples to describe lipid Mouthfeel. The thickness of lipid deposition on the tongue shows spatial variation (10-100 microm) and stopped increasing after intakes higher than 8 mL of medium-chain triglycerides (MCTs). After 2 min, only 25% of the lipid deposition was retained on oral surfaces. A difference in the thickness of lipid deposition of 25 microm resulted in significantly different perception. This work describes the in-mouth behavior of food lipids and its influence on texture perception.
The relationship between individual in-mouth aroma release and individual aroma perception was in... more The relationship between individual in-mouth aroma release and individual aroma perception was investigated. Large variations in aroma release between subjects exist and the question to answer is to what extent these individual differences have an impact on aroma perception. To assess this, 13 subjects performed a 3-AFC test (three alternative forced choices), while their in-mouth aroma release simultaneously was measured by proton transfer reaction mass spectrometry (PTR-MS). In each test three solutions were consumed by the panellists, two of them were the reference at 6 ppm V, one the target at varying concentrations from 6.5 to 15 ppmV. The subjects had to identify the sample of the highest aroma concentration. A correlation between individual aroma release and aroma perception could be confirmed. Higher ability to discriminate between samples of low concentration difference was found for those subjects that showed a higher in-mouth release and a lower variability.
The Journal of nutrition, 2008
Fructooligosaccharides (FOS) are considered prebiotics because of their ability to promote growth... more Fructooligosaccharides (FOS) are considered prebiotics because of their ability to promote growth of specific beneficial gut bacteria, such as bifidobacteria. Some studies reported potential immune-modulating properties. The aim of this study was to investigate the effect of FOS:inulin mix on murine response to Salmonella vaccine and evaluate the relevance toward protection against Salmonella infection. Balb/c mice were fed a diet containing 5% FOS:inulin mix or a control diet 1 wk before oral immunization with a suboptimal dose of live attenuated Salmonella typhimurium vaccine. Four weeks after vaccination, mice were infected with LD100 of virulent S. typhimurium. Specific blood Salmonella immunoglobulin G and fecal immunoglobulin A significantly increased in mice fed the diet containing prebiotics compared with control mice 4 wk postimmunization. Peritoneal macrophage phagocytic activity also significantly increased in FOS:inulin-fed mice at 1 wk postimmunization compared with con...
The Journal of nutrition, 2005
We studied the ability of the probiotic organism Enterococcus faecium SF68 to antagonize Giardia ... more We studied the ability of the probiotic organism Enterococcus faecium SF68 to antagonize Giardia intestinalis infection in mice. Oral feeding of E. faecium strain SF68 starting 7 d before inoculation with Giardia trophozoites significantly increased the production of specific anti-Giardia intestinal IgA and blood IgG. This humoral response was mirrored at the cellular level by an increased percentage of CD4(+) T cells in the Peyer's patches and in the spleens of SF68-fed mice. The improvement of specific immune responses in probiotic-fed mice was associated with a diminution in the number of active trophozoites in the small intestine as well as decreased shedding of fecal Giardia antigens (GSA65 protein). The ability of SF68 to stimulate the immune system at both mucosal and systemic levels highlights mechanisms by which this probiotic might antagonize pathogens in vivo. Taken together, the data demonstrate the strong potential of strain SF68 to prevent protozoa from causing int...
Journal of Agricultural and Food Chemistry, 2008
Temporal release and retention of aroma compounds from structured emulsions (where unsaturated mo... more Temporal release and retention of aroma compounds from structured emulsions (where unsaturated monoglycerides are added to the oil) and conventional oil-in-water emulsions were studied using in vitro dynamic headspace analysis by proton-transfer reaction mass spectrometry and static headspace analysis by gas chromatography-mass spectrometry. Under dynamic conditions, the structured emulsion exhibited delayed release compared to the oil-in-water emulsion containing the same lipid content of 5%. The time to maximum concentration T max of amphiphilic and lipophilic aroma compounds increased by a factor of 1.2 (for 3E-hexenal) to 1.9 (for octanal). The aroma release profile of the 5% lipid structured emulsion was close to that obtained for the oil-in-water emulsion containing 10% lipid. Under static conditions, the 5% lipid structured emulsion retained more of the most lipophilic aroma compounds than its counterpart 5% oil-in-water nonstructured emulsion. The present study provides potential solutions for modulating aroma release profiles of reduced-fat foods by self-assembly structures.
Journal of Agricultural and Food Chemistry, 2008
Lipids between the tongue and palate strongly contribute to the sensory impact of a product. Mout... more Lipids between the tongue and palate strongly contribute to the sensory impact of a product. Mouthfeel is a sensory attribute responsible for distinguishing reduced fat from full fat food products. The aim of this work was to quantify the distribution, deposition, and retention of lipids on the tongue and palate upon oral processing and relate this to texture. The thickness of lipid deposition was measured in mouth by fluorescence. A trained panel evaluated the perceived intensity of samples to describe lipid Mouthfeel. The thickness of lipid deposition on the tongue shows spatial variation (10-100 microm) and stopped increasing after intakes higher than 8 mL of medium-chain triglycerides (MCTs). After 2 min, only 25% of the lipid deposition was retained on oral surfaces. A difference in the thickness of lipid deposition of 25 microm resulted in significantly different perception. This work describes the in-mouth behavior of food lipids and its influence on texture perception.
Journal of Agricultural and Food Chemistry, 2003
The goal of this study was to better understand the correspondence between sensory perception and... more The goal of this study was to better understand the correspondence between sensory perception and in-nose compound concentration. Five aroma compounds at three different concentrations increasing by factors of 4 were added to four matrixes (water, skim milk, 2.7% fat milk, and 3.8% fat milk). These were evaluated by nosespace analysis with detection by proton transfer reaction mass spectrometry (PTR-MS), using five panelists. These same panelists evaluated the perceived intensity of each compound in the matrixes at the three concentrations. PTR-MS quantification found that the percent released from an aqueous solution swallowed immediately was between 0.1 and 0.6%, depending on the compound. The nosespace and sensory results showed the expected effect of fat on release, where lipophilic compounds showed reductions in release as fat content increases. The effect is less than that observed in headspace studies. A general correlation between nosespace concentration and sensory intensity ratings was found. However, examples of perceptual masking were found where higher fat milks showed reductions in aroma compound intensity ratings, even if the nosespace concentrations were the same.
Food Quality and Preference, 2009
To better understand how different sensory attributes combine to produce a refreshing sensation, ... more To better understand how different sensory attributes combine to produce a refreshing sensation, we used a gel model system to vary the composition of ingredients selected to modulate the refreshing sensation: cooling agent, citric acid, peach and mint flavourings and xanthan. A group of 160 target consumers rated the refreshing intensity of the gels and a trained sensory panel evaluated the sensory properties of the same gels using Quantitative Descriptive Analysis Ò . An internal preference mapping methodology was applied to identify the contribution of the products' sensory characteristics to the refreshing scores given by consumers. Consumers agreed quite well on the least refreshing gels which were the sweetest, but they differed regarding the sensory drivers of the most refreshing gels. Three segments of consumers were identified for which refreshing was driven mainly by perception of cold/mint, acid and thickness, respectively. Food habits may be partly responsible for the different key sensory drivers among consumer clusters.
Calcified Tissue International, 2006
The PIXImus dual-energy X-ray absorptiometer (DXA) is designed to measure body composition, bone ... more The PIXImus dual-energy X-ray absorptiometer (DXA) is designed to measure body composition, bone mineral content (BMC), area (BA), and density (BMD) in mice and rats. The aims of this study were to longitudinally measure BMC, BA, and BMD in growing rats and to identify potential technical problems associated with the PIXImus. Total femur and lumbar DXA measurements, body weight, and length of initially 3-week-old rats (n = 10) were taken at weeks 5, 9, and 14. BMC and BMD of femoral metaphyseal and diaphyseal regions rich in trabecular and cortical bone, respectively, were obtained. Results showed significant increases in body weight, total femur BMC and BMD, lumbar area, length, BMC, and BMD at each time point. There was a significant positive correlation between body weight and total femur BMD (r = 0.97, P < 0.001) as well as lumbar BMD (r = 0.99, P < 0.001). BMD values for the femoral metaphyseal region and the lumbar spine were also positively correlated (r = 0.96, P < 0.01). Several technical issues (e.g., positioning of animals), difficulties (e.g., in analysis of images), and limitations (e.g., inability to detect underdeveloped calcified bone in growing animals and bone edge detection) of the software pertinent to the PIXImus were evident. In conclusion, despite limitations in the software, the PIXImus is a valuable tool for studying skeletal development of growing rats.
Bioinformatics, 2004
Motivation: Microarray technology has become a powerful research tool in many fields of study; ho... more Motivation: Microarray technology has become a powerful research tool in many fields of study; however, the cost of microarrays often results in the use of a low number of replicates (k ). Under circumstances where k is low, it becomes difficult to perform standard statistical tests to extract the most biologically significant experimental results. Other more advanced statistical tests have been developed; however, their use and interpretation often remain difficult to implement in routine biological research. The present work outlines a method that achieves sufficient statistical power for selecting differentially expressed genes under conditions of low k , while remaining as an intuitive and computationally efficient procedure. Results: The present study describes a Global Error Assessment (GEA) methodology to select differentially expressed genes in microarray datasets, and was developed using an in vitro experiment that compared control and interferon-γ treated skin cells. In this experiment, up to nine replicates were used to confidently estimate error, thereby enabling methods of different statistical power to be compared. Gene expression results of a similar absolute expression are binned, so as to enable a highly accurate local estimate of the mean squared error within conditions. The model then relates variability of gene expression in each bin to absolute expression levels and uses this in a test derived from the classical
Food Quality and Preference, 2008
In preference mapping, mean liking scores of the products often appear to be the resultant of div... more In preference mapping, mean liking scores of the products often appear to be the resultant of diverging opinions that need to be summarized with a small number of homogeneous consumer clusters. For doing so, the common practice of most consumer research agencies is to use hierarchical clustering methods. The objective of this work is to compare this common practice with partitioning methods (e.g. k-means clustering) that we generally apply. These comparisons are made on actual Nestlé studies and on simulated datasets. For actual studies, methods are compared according to four indexes measuring the compactness and the separation of the clustering. For simulated data, the methods are compared on their ability to recover the a priori defined clusters. Results show that common partitioning methods like k-means outperform hierarchical methods for clustering consumers in preference mapping.
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Papers by Nicolas Antille