Multiscale and multimodal spectral Imaging for mapping cell wall polymers in plant organs

Multiscale and Multimodal Spectral Imaging for Mapping Cell Wall Polymers in Plant Organs. 2nd International Plant Spectroscopy Conferenc

Autofluorescence multispectral image analysis at the macroscopic scale for tracking wheat grain tissues: a novel approach for a more specific identification of wheat grain dietary fibre

Wheat grain contains about 12-14% of fibres mainly located in the outer layers. The composition and the structure of wheat dietary fibres, as well as the nature and amount of co-passengers, vary according to the tissue where they are originated from. The aleurone layer is rich in low substituted arabinoxylans esterified to ferulic acid whereas outer pericarp contains highly substituted arabinoxylans but also cellulose and lignin. Consequently wheat dietary fibres properties showed a high variability according to their tissue of origin within the grain, which deeply impact their nutritional effects. If the identification of tissues in wheat grain is commonly performed, it remains challenging for food ingredient such as mill streams (flour, bran etc).Equipements are now available to acquire multispectral fluorescence images at the macroscopic scale using filters with specific excitation/emission wavelengths. These fluorescence macroscopes allow obtaining images of a representative number of particles together with a spatial resolution of less than 3 μm. In such images, the intensities measured for each pixel, though they are not spectra, can be assembled to form spectral profiles. To identify the tissular origin from this information, we propose to develop a prediction model on particles using calibration data coming from the observation of tissue sections. This approach is based on several assumptions. The first one is that the multispectral autofluorescence of plant tissues is specific and the second is that it is possible to measure fluorescence intensities in a reproducible way. The objective of the present work was to check the fluorescence macroscope as an efficient device for measuring and comparing fluorescence intensities.The variability of fluorescence profiles was studied by selecting pixels in cross-section or in particles mounted in air or in water. The statistical variations were studied by principal component analysis and variance analysis. The first effect, mainly described by principal component 1, was to differentiate aleurone layer from pericarp tissue. The second effect, mainly described by component 2, was a difference between the two mounting media. The differences between sections or powders were not correlated to the other factors and were considered as not significant. Our results show that profiles extracted from multispectral images of cross-sections or particles are similar and allow the identification of wheat grain tissues. If implemented, the prediction from cross-section could be less tedious than other methods requiring dissection and lead to the identification of more tissues. We have demonstrated the proof of concept of tracking wheat dietary fibre origin by predicting tissues on images of particles. This method could help to better qualify flours and various milling fractions as well as to control whole grain products

Effect of lens care system on silicone hydrogel contact lens wettability

Purpose: The purpose was to compare the effect of the repeated usage of two care systems (one hydrogen peroxide cleaning and disinfecting system and one polyaminopropyl biguanide (PHMB) containing multi-purpose system) with silicone hydrogel contact lenses worn for three months on a daily wear modality. A specific aspect of interest was of the effect of the care systems on contact lens wettability. Methods: Seventy-four symptomatic contact lens wearers, habitually wearing either ACUVUE® OASYS® (n = 37) or PureVision™ (n = 37), constituted the study population. The study was a two-arm prospective, investigator-masked, bilateral study of three-month duration to evaluate the effects of CLEAR CARE® compared with renu® fresh™. The subjects were randomized to one of the two lens care systems. Contact lens wettability and surface cleanliness were assessed with the Tearscope and reported in terms of pre-lens non-invasive break-up time (PL-NIBUT) and visible deposits. Baseline assessments at enrollment were with the subjects’ own contact lenses worn for at least 6 h when using their habitual PHMB-preserved care system and at the dispensing visit with new contact lenses. At the follow-up visits, the contact lenses were worn for at least 6 h, and were at least 11 days old for ACUVUE® OASYS® and 25 days old for PureVision™. Results: The results obtained showed that: (i) with CLEAR CARE®, a significant improvement in contact lens wettability was recorded compared with the habitual care system at the three-month follow-up visit (mean median PL-NIBUT 5.8 vs. 4.0 s, p < 0.001). Further, with this same lens care system a significant increase in wettability was observed at the three-month follow-up visit compared with dispensing (mean median PL-NIBUT 5.8 vs. 4.5 s, p = 0.022). (ii) Whereas no difference in contact lens wettability was observed at dispensing between the two lens care groups (mean PL-NIBUT: 4.5 vs. 4.2 s, p = 0.518), a significantly more stable pre-lens tear film was observed with CLEAR CARE® than with renu® fresh™ at both the two-month (mean PL-NIBUT: 4.6 vs. 3.7 s, p = 0.005) and three-month (mean PL-NIBUT: 5.8 vs. 4.2 s, p = 0.028) visits. iii. With renu® fresh™, no significant differences were observed at the end of three months of use compared with either the habitual care system or the new contact lens solution (mean PL-NIBUT: 3 M 4.2 vs. Disp 4.2 s (p = 0.420) vs. enrolment habitual care solution 5.1 s (p = 0.734)). iv. With CLEAR CARE® significant increases in the incidence of surfaces free of both mucus (3 month 95%. vs. habitual solution 82% enrolment; p = 0.005) and lipid (3 month 87% vs. habitual solution 72% enrolment; p = 0.009) were observed. Conclusion: Significantly better contact lens wettability and surface cleanliness were achieved for ACUVUE® OASYS® and PureVision™ with CLEAR CARE® than with renu® fresh™ at the end of three months of use

Functional Simulation of the Uses of the Onboard Inter-Satellite Network in a Swarm

There are several network simulators (some on the shelves) that are very useful and helpful for network engineering. Nevertheless, none is efficient enough for simulating an onboard network spread among spacecrafts that are moving in space according to Kepler laws. Therefore, we tried to fill this gap by building our own tool based on the CNES expertise in space simulator benches. Our bench simulates the environment and the dynamics of each spacecraft, provides a model of the physical layer of the network layer (i.e. Radio Frequency transmission between moving vehicles) and offers an interface to run actual Flight Software. Embedding flight software allows us to perform functional demonstration of the network use at system level. As a first step, in order to characterize the network, we have implemented a routing policy based on the flooding principle

Prediction Of Beef Fatty Acid Composition Using Near Infrared Spectroscopy: Effects Of Tissue And Sample Preparations

International audienceThe aims of the study were to determine the best site of bovine carcass for predicting fatty acid (FA) composition using a NIRS (near infrared spectroscopy) portable equipment and to study the effect of different methods of sample preparation. 78 animals were sampled from different types and rearing systems. Seven tissues (Longissimus thoracis, Infraspinatus, Diaphragma, Rectus abdominis, shoulder subcutaneous adipose tissue (SAT), intercostal SAT and intermuscular fat at the 5th rib) were measured after sampling and grinding in liquid nitrogen. The effect of samples preparation were measured on carcass (C0), muscle without grinding (B0), ground with a meat chopper (B1), ground with a knife mill (B2) on RA muscle. FA composition was assessed using gas chromatograph and the spectra were measured at wavelengths between 350 and 2500 nm. For adipose tissue, FA were not correctly predicted from NIRS. However, predictions were more satisfactory for the major FA (C16:0, C18:0, C18:1d9c), total saturated and monounsaturated FA of muscles. The results show a better prediction of FA composition concomitant with an increased gradient of sample homogenization. For other FA and especially polyunsaturated fatty acids, the performances were not satisfactory for quantitative purposes whatever the grinding method

The antimalarial MMV688533 provides potential for single-dose cures with a high barrier to

The emergence and spread of Plasmodium falciparum resistance to first-line antimalarials creates an imperative to identify and develop potent preclinical candidates with distinct modes of action. Here, we report the identification of MMV688533, an acylguanidine that was developed following a whole-cell screen with compounds known to hit high-value targets in human cells. MMV688533 displays fast parasite clearance in vitro and is not cross-resistant with known antimalarials. In a P. falciparum NSG mouse model, MMV688533 displays a long-lasting pharmacokinetic profile and excellent safety. Selection studies reveal a low propensity for resistance, with modest loss of potency mediated by point mutations in PfACG1 and PfEHD. These proteins are implicated in intracellular trafficking, lipid utilization, and endocytosis, suggesting interference with these pathways as a potential mode of action. This preclinical candidate may offer the potential for a single low-dose cure for malaria

The antimalarial MMV688533 provides potential for single-dose cures with a high barrier to

The emergence and spread of Plasmodium falciparum resistance to first-line antimalarials creates an imperative to identify and develop potent preclinical candidates with distinct modes of action. Here, we report the identification of MMV688533, an acylguanidine that was developed following a whole-cell screen with compounds known to hit high-value targets in human cells. MMV688533 displays fast parasite clearance in vitro and is not cross-resistant with known antimalarials. In a P. falciparum NSG mouse model, MMV688533 displays a long-lasting pharmacokinetic profile and excellent safety. Selection studies reveal a low propensity for resistance, with modest loss of potency mediated by point mutations in PfACG1 and PfEHD. These proteins are implicated in intracellular trafficking, lipid utilization, and endocytosis, suggesting interference with these pathways as a potential mode of action. This preclinical candidate may offer the potential for a single low-dose cure for malaria

Exploration fonctionnelle des cellules cutanées en réponse au glyoxal et identification de facteurs impliqués dans le retard de cicatrisation lié au diabète : test de la Metformine comme molécule antiglycante

The risk of developing chronic wounds such as diabetic foot is prevalent among diabetic patients, leading to amputation. Although causes leading to wound healing defect are still poorly understood, it has been shown that Advanced Glycation End-products (AGEs) like Nε-(carboxymethyl)lysine (CML), resulting from chronic hyperglycemia, are accumulated in the skin. In this work, we aimed to highlight cutaneous glycation effects to better understand the wound healing delay among diabetic patients. First, we studied human dermal fibroblast behavior after the addition of a strong glycating agent: the glyoxal. We validated that the addition of glyoxal triggered an accumulation of CML linked to a drastic decrease in fibroblasts proliferation and migration. It appeared that in presence of glyoxal, type I collagen is correctly produced but it does not mature properly and it cannot induce the formation of collagen fibers. These results evidenced the pronounced effects of glycation on wound healing and skin quality. Moreover, glyoxal induced a strong accumulation of lipid droplets in the cytoplasm of fibroblasts, demonstrating a significant imbalance in lipid metabolism as observed in diabetic patients. To go further, we proved that metformin, as anti-glycating molecule, could prevent lipid droplets accumulation. Next, a 3D skin model with keratinocytes, fibroblasts and endothelial cells was performed with glyoxal and metformin. Interestingly, the presence of glyoxal decreased vessel maturity and disturbed epidermal differentiation with a decrease of epidermal thickness and keratin 1 expression. A 3D wound healing skin model showed a slowdown of keratinocyte migration in response to glyoxal. These 3D models allowed us to highlight that metformin restores epidermal differentiation and ameliorates vessel stability. However it was not related to the restoration of keratinocytes migration. Finally, the application of a metformin-containing dressing on chronic compression wounds performed on diabetic mice was not related to a wound healing improvement in these experimental conditions. Taking together, our results could explain skin fragility found in diabetic patients. Indeed, glyoxal seemed to act at different levels and disturbed some wound healing stages, such as proliferation, migration, neo-epidermis formation and remodeling of extracellular matrix. These encouraging results open broad perspectives for the study of skin diabetic complications and the establishment of innovative therapeutic approaches and particularly, the high potential of metformin.Les personnes diabétiques présentent un risque accru de développer des plaies chroniques, le plus souvent au niveau du pied, pouvant mener jusqu’à l’amputation. Les causes de ce défaut de cicatrisation sont encore mal connues. Il a cependant été montré qu’une des conséquences de l’hyperglycémie est l’accumulation de produits terminaux de glycation, ou AGEs, tel que le Nε-(carboxymethyl)lysine (CML), au niveau de la peau des patients. Notre projet a eu pour objectif de mettre en évidence les effets de la glycation au niveau cutané afin de mieux comprendre les défauts de cicatrisation des diabétiques. Dans un premier temps, notre travail a consisté à étudier le comportement des fibroblastes dermiques humains en réponse à un agent de glycation fort : le glyoxal. Nous avons montré une diminution importante de la prolifération et de la migration cellulaire à la suite d’une accumulation de CML. Il apparaît qu’en présence de glyoxal les fibroblastes produisent correctement le collagène I mais sont incapables de le cliver et/ou de l’assembler correctement. Ces résultats suggèrent que la glycation pourrait retarder la fermeture d’une plaie et induire une fragilité cutanée. Nous avons également pu mettre en évidence une forte accumulation de vésicules lipidiques dans le cytoplasme des fibroblastes en réponse au glyoxal, ce qui traduit un déséquilibre important du métabolisme des lipides comme il est observé chez les diabétiques. Pour aller plus loin, la metformine aux propriétés antiglycantes, pourrait permettre de limiter l’accumulation lipidique. Par la suite, un modèle de peaux 3D avec kératinocytes, fibroblastes et cellules endothéliales a été testé en présence de glyoxal et/ou de metformine. Le glyoxal induit une diminution de la maturité des vaisseaux sanguins, une forte perturbation de la différenciation épidermique avec notamment une diminution de l’épaisseur de l’épiderme et de l’expression de la kératine 1. Dans un modèle 3D de cicatrisation, nous avons montré que la migration des kératinocytes est drastiquement diminuée après traitement au glyoxal. Ces modèles 3D nous ont permis de mettre en évidence que la metformine est capable de rétablir partiellement la différenciation épidermique et d’améliorer la stabilité des vaisseaux sanguins, mais ne permet pas d’augmenter la migration des kératinocytes. Enfin, nous avons testé un pansement contenant de la metformine sur des plaies de compression chroniques induites chez la souris diabétique. Sur ce modèle in vivo nous n’avons cependant pas pu mettre en évidence une amélioration de la cicatrisation en présence de metformine. Ces travaux de thèse ont permis de mettre en évidence que la glycation est à l’origine d’une perturbation forte de différents paramètres essentiels au processus de cicatrisation comme la migration, la prolifération, la différenciation et le remodelage de la matrice extracellulaire. Ces résultats ouvrent d'importantes perspectives pour étudier les complications cutanées liées au diabète et la mise en place d'approches thérapeutiques innovantes comme la metformine qui montre un fort potentiel

Employee Loyalty and Organizational Performance: A Critical Survey

International audiencePurpose – The paper aims to clarify the relationship between employee loyalty and organizational performance. It starts with the idea that the employee loyalty creates value for the organization. This statement is widely endorsed in the literature although there is little consensus on the definition of loyalty. The paper proposes a refined synthesis of the literature on the link between employee loyalty and organizational performanceDesign/methodology/approach – The paper addresses the question of whether there is a robust positive link between employee loyalty and organizational performance. We start by reviewing the various, sometimes divergent, approaches to employee loyalty in the literature and then compare the different indicators of loyalty in relation to their relevance to different indicators of performance.Findings – The paper provides a critical overview of the different existing conceptions of employee loyalty. It points out ambiguity about both the theoretical contours of the concept, and practical means of making it a source of value for the organization. The paper shows that the link between employee loyalty and performance varies according to the type of indicators usedResearch limitations/implications – The paper highlights a variety of indicators for employee loyalty to their firm and for organizational performance. But much research remains to be conducted, notably on the managerial levers that might consolidate or improve organizational performance.Originality/value – This paper fulfils an identified need to survey a fragmented theoretical field of analysis

Manifestations, déterminants et conséquences de la fidélité des salariés : Une lecture critique de la littérature

International audienceRésumé : Bien que la fidélité des salariés soit un thème central pour les organisations, il n’existe pas de consensus dans la littérature sur la définition-même du concept. Les travaux restent très ambigus sur la nature, les origines, les expressions ou encore les retombées organisationnelles de la fidélité des salariés. Face à ce constat, nous proposons une grille de lecture synthétique de la littérature distinguant les indicateurs de fidélité de ses déterminants et de ses effets pour les organisations.Abstract: While employees’ loyalty is a central theme for organizations, no consensus emerges from literature about the definition of the concept. Works are very ambiguous concerning the nature of employees’ loyalty, concerning its origins, concerning its expressions and concerning its organizational consequences. Based on this observation, we propose a synthetic analysis grid which distinguishes the determining factor, the manifestations and the organizational consequences of employees’ loyalty