Neural mechanisms of odour imagery induced by non-figurative visual cues

Odour imagery, the ability to experience smell when an appropriate stimulus is absent, has widely been documented as being particularly difficult. However, previous studies have shown the beneficial effect of visual cues (e.g., pictures or words) to facilitate performance in numerous tasks of olfactory nature. Therefore, the use of visual cues to evoke odours seems relevant. In this study, our interest is directed towards non-figurative coloured arrangements, which result from a patented technology and aim at chromatically representing any smell from its chemical composition and sensory description. The aim of this study was to characterise the neural mechanisms of odour imagery facilitated by these non-figurative coloured arrangements. Using functional magnetic resonance imaging, we recorded and compared hemodynamic responses during odour imagery facilitated by non-figurative coloured arrangements and pictures. Our findings reveal that the use of non-figurative coloured arrangements during odour imagery solicits olfactory and non-olfactory brain regions (orbitofrontal cortex, insula, hippocampus, thalamus, dorsolateral prefrontal cortex and supplementary motor area), which are mainly involved in olfactory processing and multimodal integration. Moreover, very similar cortical activity was found between the use of non-figurative coloured arrangements and pictures during odour imagery, with increased activity in the supplementary motor area during the use of coloured arrangements only. Overall, non-figurative coloured arrangements could become a robust tool to visually evoke odours without requiring prior familiarity with the depicted odour. Future studies should use psychometric measures to determine the relationships between brain activation, odour imagery ability and vividness of the generated odour images.

fNIRS a novel neuroimaging tool to investigate olfaction, olfactory imagery, and crossmodal interactions: a systematic review

Olfaction is understudied in neuroimaging research compared to other senses, but there is growing evidence of its therapeutic benefits on mood and well-being. Olfactory imagery can provide similar health benefits as olfactory interventions. Harnessing crossmodal visual-olfactory interactions can facilitate olfactory imagery. Understanding and employing these cross-modal interactions between visual and olfactory stimuli could aid in the research and applications of olfaction and olfactory imagery interventions for health and wellbeing. This review examines current knowledge, debates, and research on olfaction, olfactive imagery, and crossmodal visual-olfactory integration. A total of 56 papers, identified using the PRISMA method, were evaluated to identify key brain regions, research themes and methods used to determine the suitability of fNIRS as a tool for studying these topics. The review identified fNIRS-compatible protocols and brain regions within the fNIRS recording depth of approximately 1.5 cm associated with olfactory imagery and crossmodal visual-olfactory integration. Commonly cited regions include the orbitofrontal cortex, inferior frontal gyrus and dorsolateral prefrontal cortex. The findings of this review indicate that fNIRS would be a suitable tool for research into these processes. Additionally, fNIRS suitability for use in naturalistic settings may lead to the development of new research approaches with greater ecological validity compared to existing neuroimaging techniques.

French Vividness of Olfactory Imagery Questionnaire: A Potential Tool for Diagnosing Olfactory Loss by Assessing Olfactory Imagery?

Several studies have shown a significant relationship between smelling and olfactory imagery abilities. The primary aim of the present study was to validate a French version of the Vividness of Olfactory Imagery Questionnaire (VOIQ). The secondary aim was to investigate its capability to differentiate individuals with smell loss from healthy individuals. After having elaborated a French translation of the VOIQ (fVOIQ), we evaluated olfactory imagery abilities of 387 French participants who anonymously self-completed the fVOIQ: 121 pathologic individuals (hyposmic and anosmic), 244 normosmic individuals (healthy non-expert), and 22 fragrance experts. Significant split-half reliability as expressed by Spearman correlation coefficients for the global sample, as well as for each group separately, indicated the excellent internal consistency of the fVOIQ. Moreover, results revealed a significant effect of the smelling ability group on fVOIQ score, suggesting that daily olfactory stimulation is fundamental to maintaining the ability to create a vivid image and that severe loss of smell may result in progressive impairment of olfactory imagery. Our fVOIQ and the original English version seemingly have similarly high benefit in differentiating experts and normosmic individuals based on their olfactory imagery ability. Moreover, the fVOIQ seems capable of differentiating individuals with loss of smell from healthy individuals. These findings demonstrate the reliability and validity of the fVOIQ, and its capability to differentiate individuals’ smelling ability according to their olfactory imagery ability.

Physicochemical, Sensorial and Microbiological Characterization of PoroCheese, an Artisanal Mexican Cheese Made from Raw Milk

Poro cheese is a regional product originally from the area of Los Rios, Tabasco in Mexico. In the context of preserving the heritage of Poro cheese and protecting the specific characteristics that define its typicity through an origin designation, the present study was conducted to establish a general profile of Poro cheese by characterizing their physicochemical, textural, rheological, sensorial and microbiological characteristics. Differences in moisture, proteins, fats, NaCl, titrable acidity, pH, color texture and rheology amongst cheese factories were observed and ranges were established. Fifteen descriptors were generated to provide a descriptive analysis, eight of which were significantly different amongst the factories with no differences in the global acceptability of cheese. The favorite cheese had the highest scores for aroma attributes. Conventional and molecular methods were used to identify the main microorganisms, for which Lactobacillus plantarum, L. fermentum, L. farciminis and L. rhamnosus were the main microorganisms found in Porocheese. The obtained data constituted the parameters for characterizing Poro cheese, which will strongly help to support its origin appellation request process.

Fundamental aspects of noise in analog-hardware neural networks

We study and analyze the fundamental aspects of noise propagation in recurrent as well as deep, multilayer networks. The motivation of our study is neural networks in analog hardware; yet, the methodology provides insight into networks in general. Considering noisy linear nodes, we investigate the signal-to-noise ratio at the network's outputs, which determines the upper limit of computational precision. We consider additive and multiplicative noise, which can be purely local as well as correlated across populations of neurons. This covers the chief internal-perturbations of hardware networks, and noise amplitudes were obtained from a physically implemented neural network. Analytically derived descriptions agree exceptionally well with numerical data, enabling clear identification of the components critical for management and mitigation of noise. We find that analog neural networks are surprisingly robust, in particular, against noisy neurons. Their uncorrelated perturbations are almost fully suppressed, while correlated noise can accumulate. Our work identifies notoriously sensitive points while highlighting a surprising robustness of such computational systems.

Single-shot ultrafast laser processing of high-aspect-ratio nanochannels using elliptical Bessel beams

Ultrafast lasers have revolutionized material processing, opening a wealth of new applications in many areas of science. A recent technology that allows the cleaving of transparent materials via non-ablative processes is based on focusing and translating a high-intensity laser beam within a material to induce a well-defined internal stress plane. This then enables material separation without debris generation. Here, we use a non-diffracting beam engineered to have a transverse elliptical spatial profile to generate high-aspect-ratio elliptical channels in glass of a dimension 350  nm×710  nm and subsequent cleaved surface uniformity at the sub-micron level.

High aspect ratio micro-explosions in the bulk of sapphire generated by femtosecond Bessel beams

Femtosecond pulses provide an extreme degree of confinement of light matter-interactions in high-bandgap materials because of the nonlinear nature of ionization. It was recognized very early on that a highly focused single pulse of only nanojoule energy could generate spherical voids in fused silica and sapphire crystal as the nanometric scale plasma generated has energy sufficient to compress the material around it and to generate new material phases. But the volumes of the nanometric void and of the compressed material are extremely small. Here we use single femtosecond pulses shaped into high-angle Bessel beams at microjoule energy, allowing for the creation of very high 100:1 aspect ratio voids in sapphire crystal, which is one of the hardest materials, twice as dense as glass. The void volume is 2 orders of magnitude higher than those created with Gaussian beams. Femtosecond and picosecond illumination regimes yield qualitatively different damage morphologies. These results open novel perspectives for laser processing and new materials synthesis by laser-induced compression.

Mapping human risk of infection with Borrelia burgdorferi sensu lato, the agent of Lyme borreliosis, in a periurban forest in France

Lyme borreliosis is a major zoonosis in Europe, with estimates of over 26,000 cases per year in France alone. The etiological agents are spirochete bacteria that belong to the Borrelia burgdorferi sensu lato (s. l.) complex and are transmitted by hard ticks among a large range of vertebrate hosts. In Europe, the tick Ixodes ricinus is the main vector. In the absence of a vaccine and given the current difficulties to diagnose and treat chronic Lyme syndromes, there is urgent need for prevention. In this context, accurate information on the spatial patterns of risk of exposure to ticks is of prime importance for public health. The objective of our study was to provide a snapshot map of the risk of human infection with B. burgdorferi s. l. pathogens in a periurban forest at a high resolution, and to analyze the factors that contribute to variation in this risk. Field monitoring took place over three weeks in May 2011 in the suburban Sénart forest (3,200ha; southeast of Paris), which receives over 3 million people annually. We sampled ticks over the entire forest area (from 220 forest stands with a total area of 35,200m(2)) and quantified the density of questing nymphs (DON), the prevalence of infection among nymphs (NIP), and the density of infected nymphs (DIN), which is the most important predictor of the human risk of Lyme borreliosis. For each of these response variables, we explored the relative roles of weather (saturation deficit), hosts (abundance indices of ungulates and Tamias sibiricus, an introduced rodent species), vegetation and forest cover, superficial soil composition, and the distance to forest roads. In total, 19,546 questing nymphs were collected and the presence of B. burgdorferi s. l. was tested in 3,903 nymphs by qPCR. The mean DON was 5.6 nymphs per 10m(2) (standard deviation=10.4) with an average NIP of 10.1% (standard deviation=0.11). The highest DIN was 8.9 infected nymphs per 10m(2), with a mean of 0.59 (standard deviation=0.6). Our mapping and modeling revealed a strong heterogeneity of risk within the forest. The highest risk was found in the eastern part of the forest and localized patches in the northwestern part. Lyme borreliosis risk was positively associated with stands of deciduous trees (mainly oaks) and roe deer abundance. Contrary to expectations, DIN actually increased with distance from the point of introduction of T. sibiricus (i.e., DIN was higher in areas with potentially lower abundances of T. sibiricus). Thus, despite the fact that T. sibiricus is an important reservoir host for B. burgdorferi s. l., our study found that other explanatory factors played a more important role in determining the density of infected ticks. Precise mapping of the risk of exposure to Lyme borreliosis in a highly visited forest represents an important tool for targeting prevention and control measures, as well as making the general public and local health officials aware of the risks.

Spatiotemporal structure of femtosecond Bessel beams from spatial light modulators

We numerically investigate the spatiotemporal structure of Bessel beams generated with spatial light modulators (SLMs). Grating-like phase masks enable the spatial filtering of undesired diffraction orders produced by SLMs. Pulse front tilt and temporal broadening effects are investigated. In addition, we explore the influence of phase wrapping and show that the spatiotemporal structure of SLM-generated femtosecond Bessel beams is similar to Bessel X-pulses at short propagation distance and to subluminal pulsed Bessel beams at long propagation distance.

Arbitrary nonparaxial accelerating periodic beams and spherical shaping of light

We report the observation of arbitrary accelerating beams (ABs) designed using a nonparaxial description of optical caustics. We use a spatial light modulator-based setup and techniques of Fourier optics to generate circular and Weber beams subtending over 95 deg of arc. Applying a complementary binary mask also allows the generation of periodic ABs taking the forms of snake-like trajectories, and the application of a rotation to the caustic allows the first experimental synthesis of optical ABs upon the surface of a sphere in three dimensions.

Sending femtosecond pulses in circles: highly nonparaxial accelerating beams

We use caustic beam shaping on 100 fs pulses to experimentally generate nonparaxial accelerating beams along a 60° circular arc, moving laterally by 14 µm over a 28 µm propagation length. This is the highest degree of transverse acceleration reported to our knowledge. Using diffraction integral theory and numerical beam propagation simulations, we show that circular acceleration trajectories represent a unique class of nonparaxial diffraction-free beam profile which also preserves the femtosecond temporal structure in the vicinity of the caustic.

Arbitrary accelerating micron-scale caustic beams in two and three dimensions

We generate arbitrary convex accelerating beams by direct application of an appropriate spatial phase profile on an incident Gaussian beam. The spatial phase calculation exploits the geometrical properties of optical caustics and the Legendre transform. Using this technique, accelerating sheet caustic beams with parabolic profiles (i.e. Airy beams), as well as quartic and logarithmic profiles are experimentally synthesized from an incident Gaussian beam, and we show compatibility with material processing applications using an imaging system to reduce the main intensity lobe at the caustic to sub-10 micron transverse dimension. By applying additional and rotational spatial phase, we generate caustic-bounded sheet and volume beams, which both show evidence of the recently predicted effect of abrupt autofocussing. In addition, an engineered accelerating profile with femtosecond pulses is applied to generate a curved zone of refractive index modification in glass. These latter results provide proof of principle demonstration of how this technique may yield new degrees of freedom in both nonlinear optics and femtosecond micromachining.

Active food packaging evolution: transformation from micro- to nanotechnology

Predicting which attributes consumers are willing to pay extra for has become straightforward in recent years. The demands for the prime necessity of food of natural quality, elevated safety, minimally processed, ready-to-eat, and longer shelf-life have turned out to be matters of paramount importance. The increased awareness of environmental conservation and the escalating rate of foodborne illnesses have driven the food industry to implement a more innovative solution, i.e. bioactive packaging. Owing to nanotechnology application in eco-favorable coatings and encapsulation systems, the probabilities of enhancing food quality, safety, stability, and efficiency have been augmented. In this review article, the collective results highlight the food nanotechnology potentials with special focus on its application in active packaging, novel nano- and microencapsulation techniques, regulatory issues, and socio-ethical scepticism between nano-technophiles and nano-technophobes. No one has yet indicated the comparison of data concerning food nano- versus micro-technology; therefore noteworthy results of recent investigations are interpreted in the context of bioactive packaging. The next technological revolution in the domain of food science and nutrition would be the 3-BIOS concept enabling a controlled release of active agents through bioactive, biodegradable, and bionanocomposite combined strategy.

High aspect ratio taper-free microchannel fabrication using femtosecond Bessel beams

We present a systematic study of femtosecond laser microchannel machining in glass using nondiffracting Bessel beams. In particular, our results identify a source and focusing parameter working window where high aspect ratio taper-free microchannels can be reproducibly produced without sample translation. With appropriate source parameters, we machine channels of 2 microm diameter and with aspect ratios up to 40. We propose the filamentation stability of the Bessel beam propagation as the critical factor underlying the controlled and reproducible results that have been obtained.

Surface nanoprocessing with nondiffracting femtosecond Bessel beams

We demonstrate the application of nondiffracting Bessel beams for reproducible nanometric-scale feature patterning in glass. A femtosecond pulse zero-order Bessel beam with a central spot radius of 360 nm was used to write 500 nm radius nanocraters over a longitudinal positioning range exceeding 20 microm, with a variation in radius of less than 10%. The use of Bessel beams significantly reduces constraints on critical sample positioning in the nanoscale writing regime, enabling the use of femtosecond pulses for fast inscription of nanometer-scale features over large sample areas.

Optimization of the components concentrations of the lactoperoxidase system by RSM

AIMS

The aim of this work was to use response surface methodology (RSM) approach, a statistical mathematical tool, to model effects and interactions of glucose oxidase (GOD), glucose, lactoperoxidase (LPO) and pH-values on the thiocyanate (SCN-) peroxidation, to determine the best concentrations of lactoperoxidase system (LP-s) components in order to obtain maximal SCN- peroxidation and so to enhance the LP-s antibacterial effects.

METHODS AND RESULTS

Experimental design using RSM was used for modelling effects and interactions of GOD (28.5-142.5 IU l(-1)), glucose (0.55-11.11 mmol l(-1)), LPO (0-6284 IU l(-1)) concentrations, and pH-values (6.0-7.4) on thiocyanate peroxidation. A fixed SCN- concentration of 0.5 mmol l(-1) was used. Experiments were carried out at 4 or at 25 degrees C in 0.1 mol l(-1) phosphate buffer. Optimized concentrations for both temperatures (4 and 25 degrees C) were quite similar and were 85.5 IU l(-1) for GOD, 8 mmol l(-1) for glucose and 3927.5 IU l(-1) for LPO at an initial pH-value of 6.5. SCN- peroxidation was more efficient at 25 than at 4 degrees C. At 4 degrees C, no interaction between factors occurred. At 25 degrees C, thiocyanate peroxidation was affected by GOD/glucose, GOD/pH and LPO/pH. Thiocyanate peroxidation was mainly increased by glucose and LPO factors. The optimized system had a bacteriostatic effect on Listeria monocytogenes CIP 82110(T) and a strong bactericidal effect on Pseudomonas fluorescens CIP 6913(T).

CONCLUSIONS

Appropriate combinations of LPO, GOD, glucose concentrations and pH-values allowed maximal thiocyanate peroxidation and enhanced the antibacterial effect of the LP-s.

SIGNIFICANCE AND IMPACT OF THE STUDY

This optimization by RSM approach allowed a better understanding of the LP-s functioning, the description of the component impacts on the SCN- peroxidation, and the observation of different interactions between the factors. The antimicrobial efficiency of LP-s can be enhanced by better concentration ratios of the LP-s components.

Broadband supercontinuum interferometer for high-resolution profilometry

In this paper, it is shown that a white light supercontinuum source generated in an air-silica microstructured optical fiber pumped with picosecond pulses offers the possibility to improve fringes visibility in interferometric acquisitions. Consequently, this source combined with a spectral interferometer, reaches high-resolution profilometric measurements. Phase calculation based on seven point algorithm can perform theoretically a subnanometer resolution. This method provides a one line profile of large surfaces from the analysis of a single shot image, without any mechanical scanning.

Imaging through a scattering medium with an interferential spectrometer by selection of an amplitude modulation correlator

Low-coherence interferometric systems provide three-dimensional imaging through scattering media by measurement of the object's temporal response. An optical correlator is presented that allows direct recording of the signal issued from the object under reflection. The filtering technique enhances the image visibility and allows one to obtain an image with a good signal-to-noise ratio. The performance of two particular imaging systems, point-to-point and vertical-slice imaging, is discussed with an object comprising two cover plates that are attached.

[Imagination of women with breast cancer. About the etiologic theories of 10 patients]

The announcement of the diagnosis of a breast cancer causes a rupture in the continuity of life of the patients. For women with such a potentially mortal illness, the development of an etiologic theory, falling under a subjective appropriation of the disease, allows them to face the traumatism of the diagnostic and the course of the cancer itself. These theories, often spontaneous, sometimes supported by the psychologist's work, are a great ally for the somatician in the therapy of those women.