Food allergens: threshold levels and methodologies for risk management

Food allergies and allergen management are important problems of the public health and food industry. The idea of determining allergen concentrations in food ingredients and food products that are capable of causing severe allergic reactions is of great interest for regulatory bodies as well as consumer associations and the industry all over the world. In this connection, scientists proposed different approaches to determining the basis for assessment of severity of risks of food allergens for health of patients suffering from food allergy similar to methods of risk assessment for other hazards associated with food products (for example, chemical, microbiological). To assess risk of allergens, three different approaches were proposed: i) traditional risk assessment using the no observed adverse effect level (NOAEL)) and uncertainty factors; (ii) approach based on the benchmark dose (BMD)) and margin of exposure (MoE)); and (iii) probability models. These approaches can be used in risk management in food production and in the development of warning marking about the presence of allergens. The reliability of risk assessment will depend on a type, quality and quantity of data used for determining both population threshold levels (or threshold distributions) and an impact of an allergenic product/ingredient on a particular individual.

Comparison of verticality perception and postural sway induced by double temple-mastoidal and bipolar binaural 20 Hz sinusoidal galvanic vestibular stimulation

BACKGROUND: Galvanic vestibular stimulation (GVS) is believed to be one of the most valuable tools for studying the vestibular system. In our opinion, its combined effect on posture and perception needs to be examined more. OBJECTIVE: The present study was conducted to investigate the effect of a 20 Hz sinusoidal Galvanic Vestibular Stimulation (sGVS) on the body sway and subjective visual vertical (SVV) deviation through two sets of electrode montages (bipolar binaural and double temple-mastoidal stimulation) during a three-stage experiment (baseline, threshold, and supra-threshold levels). METHODS: While the individuals (32 normal individuals, 10 males, the mean age of 25.37±3.00 years) were standing on a posturography device and SVV goggles were put on, the parameters of the body sway and SVV deviation were measured simultaneously. Following the baseline stage (measuring without stimulation), the parameters were investigated during the threshold and supra-threshold stages (1 mA above the threshold) for 20 seconds. This was done separately for each electrode montage. Then, the results were compared between the three experimental stages and the two electrode montages. RESULTS: In both electrode montages, “the maximum amplitude” of the mediolateral (ML) and anteroposterior (AP) body sway decreased and increased in the threshold and supra-threshold stages, respectively, compared to the baseline stage. Comparison of the amount of “amplitude change” caused by each electrode montages showed that the double temple-mastoidal stimulation induced a significantly greater amplitude change in body sway during both threshold and supra-threshold stages (relative to the baseline stage). The absolute mean values of the SVV deviation were significantly different between the baseline and supra-threshold levels in both electrode montages. The SVV deviation in double temple-mastoidal stimulation was a bit greater than that in the bipolar binaural stimulation. CONCLUSION: Double temple-mastoidal stimulation has induced greater amount of change in the body sway and SVV deviation. This may be due to the more effective stimulation of the otoliths than semicircular canals.

A NOVEL METHOD FOR STUDYING THRESHOLD LEVELS FOR POSITIVE PHOTOTAXIS IN INSECTS

This paper presents a novel method for studying threshold levels for positive phototaxis of insects and smaller mobile organisms. Outdoor lighting affects light sensitive species and there is a need to evaluate the effect of light levels, spectral composition of the light and light distribution to mitigate the ecological impacts of the artificial light. For this purpose, a test box investigating the effect of light on insects in a controlled manner has been constructed. The box is equipped with a luminance source and the light levels can be varied from a maximum value continuously down to zero. The spectral composition of the light can be varied by changing the lamp or using optical filters. For visibility of the insects the box has infrared light emitting diodes in the ceiling and two wide-angle cameras monitor the light response. The functionality of the box is tested with the species greater wax moth.

Neural correlates of masked and unmasked tones: psychoacoustics and late auditory evoked potentials (LAEPs)

Hearing thresholds can be used to quantify one's hearing ability. In various masking conditions, hearing thresholds can vary depending on the auditory cues. With comodulated masking noise and interaural phase disparity (IPD), target detection can be facilitated, lowering detection thresholds. This perceptual phenomenon is quantified as masking release: comodulation masking release (CMR) and binaural masking level difference (BMLD). As these measures only reflect the low limit of hearing, the relevance of masking release at supra-threshold levels is still unclear. Here, we used both psychoacoustic and electro-physiological measures to investigate the effect of masking release at supra-threshold levels. We investigated whether the difference in the amount of masking release will affect listening at supra-threshold levels. We used intensity just-noticeable difference (JND) to quantify an increase in the salience of the tone. As a physiological correlate of JND, we investigated late auditory evoked potentials (LAEPs) with electroencephalography (EEG). The results showed that the intensity JNDs were equal at the same intensity of the tone regardless of masking release conditions. For LAEP measures, the slope of the P2 amplitudes with a function of the level was inversely correlated with the intensity JND. In addition, the P2 amplitudes were higher in dichotic conditions compared to diotic conditions. Estimated the salience of the target tone from both experiments suggested that the salience of masked tone at supra-threshold levels may only be beneficial with BMLD.

The Effect of Odour Valence and Odour Detection Threshold on the Withholding and Cancellation of Reach-to-Press Responses

Introduction Withholding uninitiated actions and cancelling ongoing ones are two main components of response inhibition, a key element of the executive control. Inhibitory performance is sensitive to emotional contexts elicited by subliminal and supraliminal visual material. However, whether stimuli from other sensory modalities, such as odours, would equally modulate response inhibition remains unclear. Here, we aimed to assess the effect of task-irrelevant odours as a function of their valence and threshold on both action withholding and action cancellation of reach-to-press movements. Method Thirty-two healthy participants performed a Go/No-Go task that included the presentation of pleasant (orange) and unpleasant (trimethyloxazole) odour primes at supra- and sub-threshold levels; clean air was included as a control condition. The reach-to-press responses were composed of an initial release phase and a subsequent reaching phase. Results Only the supra-threshold pleasant (vs. control) odour impaired action withholding. Moreover, the pleasant (vs. control) odour—presented at both sub- and supra-threshold levels—elicited more accurate Go responses, whereas the sub- and supra-threshold pleasant and unpleasant (vs. control) odours triggered faster responses in the release phase. Additionally, only the supra-threshold pleasant (vs. unpleasant) odour impaired action cancellation in the reaching phase. Furthermore, reaching responses were slower following the supra-threshold unpleasant (vs. control) odour. Conclusions Our findings extend the sparse literature on the impact of odour stimuli on goal-directed behaviour, highlighting the role of both odour valence and threshold in the modulation of response inhibition. Implications Determining the mechanisms by which odour stimuli modulate response inhibition lays the foundations for research on odour-triggered disinhibition.

Study on the Effect of Gaze Position and Image Brightness on Peripheral Dimming Technique

Here, we study a low-power technique for displays based on gaze tracking, called peripheral dimming. In this work, the threshold levels of the lightness reduction ratio (LRR), where people notice differences in brightness, depending on gaze positions and image brightness, are investigated. A psychophysical experiment with five gaze positions and three image brightness conditions is performed, and the estimated threshold levels are obtained. To investigate the significance of the differences between the threshold levels, the overlap method and the Bayesian estimation (BEST) analysis are performed. The analysis results show that the difference of the threshold levels depending on the conditions is insignificant. Thus, the proposed technique can operate with a constant LRR level, regardless of the gaze position or image brightness, while maintaining the perceptual image quality. In addition, the proposed technique reduces the power consumption of virtual reality (VR) displays by 12–14% on average. We believe that the peripheral dimming technique would contribute to reducing the power of the self-luminous displays used for VR headsets with an integrated eye tracker.

AN OBSERVATIONAL STUDY OF HEARING THRESHOLDS IN PROFESSIONAL DRIVERS

Introduction: Noise has become a very important stress factor in the environment. Drivers are the most commonly affected persons due to trafc noise. The majority of drivers remain unaware about noise induced hearing loss as this is an insidious process, leading to temporary or permanent hearing impairment, but preventable. Pure Tone audiometric test is used to determine the degree of hearing loss in noise exposed individuals. Aim & Objective: To nd the hearing threshold levels for high and mid frequency sounds for both ears in Professional drivers. To evaluate the preponderance of hearing loss between right and left ear using hearing thresholds. Materials & Methods: This study was conducted in 100 Professional male drivers aged between 30-40 years who are working in Tamil Nadu State Transport Corporation, Madurai. Pure tone audiometry was used to measure the high and mid frequency hearing threshold levels in both ears. Results: The mean (SD) hearing threshold for high and mid frequency sounds was signicantly higher in left ear comparative to right ear with P value < 0.05. The statistically signicant difference in hearing loss was observed between both ears. Conclusion : Our study showed statistically signicant higher hearing threshold for high and mid frequency sounds in left ear compared to right ear, that concludes left ear is more prone for hearing loss than the right ear

An SEIR model with infected immigrants and recovered emigrants

We present a deterministic SEIR model of the said form. The population in point can be considered as consisting of a local population together with a migrant subpopulation. The migrants come into the local population for a short stay. In particular, the model allows for a constant inflow of individuals into different classes and constant outflow of individuals from the R-class. The system of ordinary differential equations has positive solutions and the infected classes remain above specified threshold levels. The equilibrium points are shown to be asymptotically stable. The utility of the model is demonstrated by way of an application to measles.