Assessment of the acrylamide intake of the Belgian population and the effect of mitigation strategies.

The acrylamide (AA) intake of the Belgian consumer was calculated based on AA monitoring data of the Belgian Federal Agency for the Safety of the Food Chain (FASFC) and consumption data of the Belgian food consumption survey coordinated by the Scientific Institute for Public Health (3214 participants of 15 years or older). The average AA exposure, calculated probabilistically, was 0.4 microg kg(-1) body weight (bw) day(-1) (P97.5 = 1.6 microg kg(-1) bw day(-1)), the main contributors to the average intake being chips (23%), coffee (19%), biscuits (13%), and bread (12%). Additionally, the impact of a number of AA mitigation scenarios was evaluated (German minimization concept, scenarios for mitigation from the literature, signal values), which is an important issue for public health as well as for policy-makers. Specific actions in cooperation with the food industry to reduce the AA content of foods seems to be a more efficient strategy than mere implementation of signal values. Considering that an important share of the AA intake is due to prepared meals, the catering industry as well as consumers need to be better informed on the various possibilities for keeping the AA content of meals as low as possible.

Heterodyne lock-in thermal coupling measurements in integrated circuits: Applications to test and characterization.

Heterodyne strategies can be used to characterize thermal coupling in integrated circuits when the electrical bandwidth of the dissipating circuit is beyond the bandwidth of the thermal coupling mechanism. From the characterization of the thermal coupling, two possible applications are described: extraction of characteristics of the dissipating circuit (the determination of the center frequency of a low-noise amplifier) and the extraction of the thermal coupling transfer function.

Exposure assessment of the Belgian population to pesticide residues through fruit and vegetable consumption.

Exposure of the Belgian consumer to pesticide residues from the consumption of fruit and vegetables was determined based on data collected in the Belgian food consumption survey performed by the Scientific Institute for Public Health and data from the Belgian Federal Agency for the Safety of the Food Chain 2005 monitoring programme. A first screening of pesticide residue exposure was performed by a deterministic approach. For most pesticide residues studied, the exposure was 100 times lower than the acceptable daily intake (ADI). However, for a high consumer (97.5th percentile of consumption) the intake could reach 23% of the ADI for imazalil, 15% for chlorpropham, 14% for the dithiocarbamates, 10% for dimethoate and lambda-cyhalothrin, and 9% for chlorpyriphos. Nevertheless, probabilistic exposure assessment performed on these pesticides in a second phase of the study indicated that, except for chlorpropham, the probability to exceed the ADI is much lower than 0.1%.

Laser scanning thermoreflectance imaging system using galvanometric mirrors for temperature measurements of microelectronic devices.

We present a thermoreflectance imaging system using a focused laser sweeping the device under test with a scanner made of galvanometric mirrors. We first show that the spatial resolution of this setup is submicrometric, which makes it adapted to microelectronic thermal measurements. Then, we studied qualitative temperature variations on two dissipative structures constituted of thin (0.35 microm) dissipative resistors, the distance between two resistors being equal to 0.8 or 10 microm. This technique combines sensitivity and speed: it is faster than a point classical thermoreflectance technique and, in addition, more sensitive than a charge-coupled device thermoreflectance imaging technique.

The kinetics of heat-induced structural changes of beta-lactoglobulin.

Heat-induced structural changes of beta-lactoglobulin were studied at temperatures ranging from 67.5 to 82.5 degrees C, and at pH 7.5. These changes were monitored by measurement of surface hydrophobicity, thiol availability, and protein solubility. Kinetic studies were conducted to quantitatively describe the contribution of hydrophobic and SH/SS interchange reactions to the thermal structural changes of beta-lactoglobulin. Results indicate that beta-lactoglobulin is sensitive to heat-induced interchange reactions with consequences for protein solubility. The extent of changes measured by the increase in surface hydrophobicity and the decrease in slow-reacting SH groups content could be described by a first-order fractional conversion model and were characterized by activation energy values of 233.9 +/- 8.6 and 148.2 +/- 6.7 kJ/mol, respectively. The break in the Arrhenius plot suggested in literature for beta-lactoglobulin denaturation was confirmed in this study only for the kinetics of exposed SH groups.

Formation kinetics of hydroxymethylfurfural, lactulose and furosine in milk heated under isothermal and non-isothermal conditions.

A detailed kinetic study of hydroxymethylfurfural, lactulose and furosine formation was performed upon heating milk at temperatures between 90 degrees C and 140 degrees C. In case of prolonged heating, formation kinetics could be described by a fractional conversion model. Considering only the first phase of the model, kinetics could be simplified to a pseudo-zero order model. A first assessment of kinetic parameters was made by isothermal experiments. Data were analysed using both a 2-step linear and a 1-step non-linear regression method. Only for furosine, did the global 1-step regression approach seem to give better results than the individual 2-step regression approach. Next, the estimated parameters k(ref) and Ea were re-evaluated under non-isothermal conditions by subjecting milk to a time variable temperature profile. Given the complexity of Maillard reaction, it seemed better to estimate kinetic parameters under non-isothermal conditions when using a simplified model. Formation of hydroxymethylfurfural, lactulose and furosine was characterized by an Ea value of 90.2 kJ/mol (k(110 degrees C) = 1.2 micromol/l, min), 99.1 kJ/mol (k(110 degrees C) = 51.5 mg/l, min) and 88.7 kJ/mol (k(110 degrees C) = 16.3 mg/100 g protein, min) respectively. Additionally, 90% joint confidence regions were constructed in order to obtain an accurate representation of the statistical confidence associated with the simultaneously estimated parameters.

Inactivation kinetics of alkaline phosphatase and lactoperoxidase, and denaturation kinetics of beta-lactoglobulin in raw milk under isothermal and dynamic temperature conditions.

A detailed kinetic study of alkaline phosphatase, lactoperoxidase and beta-lactoglobulin was carried out in the context of identifying intrinsic time-temperature indicators for controlling the heat processing of milk. The heat inactivation or denaturation of alkaline phosphatase, lactoperoxidase and beta-lactoglobulin under isothermal conditions was found to follow first order kinetics. Experimental results were analysed using both a two step linear regression and a one step non-linear regression method. Results obtained using the two statistical techniques were comparable, but the 95% confidence interval for the predicted values was smaller when the one step non-linear regression method was used, indicating its superiority for estimating kinetic parameters. Thermal inactivation of alkaline phosphatase and lactoperoxidase was characterized by z values of 5.3 deg C (D60 degrees C = 24.6 min) and 4.3 deg C (D71 degrees C = 38.6 min) respectively. For the denaturation of beta-lactoglobulin we found z values of 7.9 deg C (D7.5 degrees C = 49.9 min) in the temperature range 70-80 degrees C and 24.2 deg C (D85 degrees C = 3.53 min) in the range 83-95 degrees C. Dref and z were evaluated under dynamic temperature conditions. To estimate the statistical accuracy of the parameters, 90% joint confidence regions were constructed.

Effect of temperature and/or pressure on lactoperoxidase activity in bovine milk and acid whey.

At atmospheric pressure, inactivation of lactoperoxidase (LPO) in milk and whey was studied in a temperature range of 69-73 degrees C and followed first order kinetics. Temperature dependence of the first order inactivation rate constants could be accurately described by the Arrhenius equation, with an activation energy of 635.3 +/- 70.7 kJ/mol for raw bovine milk and 736.9 +/- 40.9 kJ/mol for diluted whey, indicating a very high temperature sensitivity. On the other hand, LPO is very pressure resistant and not or only slightly affected by treatment at pressure up to 700 MPa combined with temperatures between 20 and 65 degrees C. Both for thermal and pressure treatment, stability of LPO was higher in milk than in diluted whey. Besides, a very pronounced antagonistic effect between high temperature and pressure was observed, i.e. at 73 degrees C, a temperature where thermal inactivation at atmospheric pressure occurs rapidly, application of pressure up to 700 MPa exerted a protective effect. At atmospheric pressure, LPO in diluted whey was optimally active at a temperature of about 50 degrees C. At all temperatures studied (20-60 degrees C), LPO remained active during pressure treatment up to 300 MPa, although the activity was significantly reduced at pressures higher than 100 MPa. The optimal temperature was found to shift to lower values (30-40 degrees C) with increasing pressure.

Surface acoustic waves at the vacuum-thermoviscoelastic solid interface.

The present investigation concerns the propagation of surface waves at the vacuum-solid interface of a solid which is isotropic and thermoviscoelastic, i.e., for which the effects of heat conductivity need to be taken into account. Calculations show that, in addition to the Rayleigh wave, a thermal surface wave propagates that couples both the thermal and the elasticity effects. This latter wave is interpreted in terms of evanescent plane waves. The displacement field associated with this wave is calculated and interpreted. Some experimental results are also presented.

Organic material concentration in auditory outer hair cells measured by laser interferometry.

Outer hair cells (OHC) of the mammalian cochlea are quasicylindrical cells of different length, which play a major role in hearing at threshold. Their particular shape allows the use of a noninvasive laser interferometric technique of isolated cells in vitro in order to measure the organic material concentration (OMC), hence the density of each cell body. In most (95%) of the OHCs isolated from the same guinea pig, when the cell diameter is normalized, the results show that the cell body OMC does not vary with cell length. In different animals, the respective normalized OMC mean values can vary between 70 kg/m3 and 103 kg/m3. A few OHCs with morphological particularities often possess cell body OMCs > 103 kg/m3. The results of the interferometric measurements in isolated OHCs confirm that density variations in the cell bodies are not involved in a sound frequency coding. The in vitro OMC variations of the OHCs could be related to the isolation procedure; however, they could also correlate with actual in vivo OMC variations.

The generality of mental addition models: simple and complex addition in a decision-production task.

Recently, Widaman, Geary, Cormier, and Little (in press) offered a general componential model for simple and complex addition. In the present study, the generalizability of this model to very complex addition problems and to production task performance was tested. We investigated addition-production performance using a new research paradigm, the decision-production task. The paradigm was used to assess the reaction times of 16 adults to 100 single-digit addition problems (Experiment 1) and to very complex three-digit addition problems (Experiment 2). Generally, the results give evidence for the basic assumptions of the Widaman et al. model. Some of the results, however, demonstrate that short-term memory load factors and strategy choices also have important effects on complex addition-production performance. Furthermore, the results of both experiments indicate that, in production tasks, the nature of the elementary search/compute process can be characterized as a memory-retrieval process and that the decision-production paradigm is a valuable alternative to the classical verbal production paradigm.

Research findings on the nature of constructs in schizophrenics.

Using a personal construct theory approach, Radley (1974) proposes a theoretical view about the nature and genesis of schizophrenic thought disorder. In this study, we replicate some results of previous studies on which Radley relies and we test some implications of his view. A test, consisting of the four possible combinations of elicited and supplied constructs and elicited and supplied elements was administered on group of schizophrenics, part of them being thought disordered (TD), part of them being not thought disordered (NTD) at the moment of testing and on a matched group of normals. An additional test was administered in order to obtain a maldistribution score. Our findings confirm most of the characteristics of the TD and NTD phase in schizophrenics, as proposed by Radley and they suggest some additions to that view. Moreover, they call for some changes in the scoring system of the Grid Test for Schizophrenic Thought Disorder (Bannister & Fransella, 1967) by using the Element Consistency, Social Agreement and maldistribution scores and Intensity and Differentiation scores of only the retest.

Field independence and recognition of trait names in an incidental learning paradigm.

Field-dependent individuals are known to be superior to field-independent individuals at recognizing socially relevant material in an incidental learning paradigm. The present study tested the hypothesis that this superiority is moderated by the target-relatedness of distractors. The stimuli were trait names. To assess recognition memory a recognition list was used with distractors differing in degrees of relatedness to the targets. Results indicate that the relationship of field-dependence to false recognition of distractor traits is moderated by the target-relatedness of the latter.

Field-dependence and stability of self-view.

Contrary to Witkin's opinion, field-dependent individuals are expected to show higher stability of self-view than field-independent individuals. 73 Belgian second-year university students were submitted to the Group Embedded Figures Test. The Five Personality Factor Test measuring extraversion, friendliness, emotional instability, conscientiousness and general culture, was administered to each student for self-description (self-report) and to both parents for description of the student (mother's report and father's report). The decrease of correlation between self-report and parent's report as a function of the degree of student's field-independence supports the author's hypothesis. Results are interpreted in terms of closer attention of field-independent individuals to relevant cues.

The influence of some parental characteristics on children's primary abilities and field independence: a study of adopted children.

The Children's Embedded Figures Test and measures of V, P, N and S abilities were administered to 5-7-year-old Belgian children (33 boys and 36 girls) adopted early in life. These child variables were correlated with the main factorial dimensions of the adoptive parents' answers on the Parental Attitude Research Instrument and on Buehler's Life Goals Inventory and with the adoptive mother's child-rearing practices, determined through an interview. The PARI dimensions were unrelated to children's test performances. Reinforcement of competition and independence, an interview variable, was significantly related to several ability measures and to the CEFT, especially in girls. The significant correlations of some LGI dimensions with boys' and/or girls' primary abilities were interpreted by referring to the influence on the development of children's abilities of a future-oriented attitude toward learning and memory and of a warm parent-child interaction.