Neuregulin 1 affects leptin levels, food intake and weight gain in normal-weight, but not obese, db/db mice

Aim. - Studies in vitro have highlighted the potential involvement of neuregulin 1 (NRG1) in the regulation of energy metabolism. This effect has also been suggested in vivo, as intracerebroventricular injection of NRG1 reduces food intakes and weight gain in rodents. Thus, it was hypothesised that NRG1 might affect serum leptin levels in mice. Methods. - Weight, food intakes, energy expenditure, spontaneous physical activity and serum leptin levels were evaluated in normal-weight C57BL/6JRJ mice following intraperitoneal administration of NRG1 (50 mu g/kg, three times/week) or saline for 8 weeks. Based on the results of this first experiment, leptin-resistant obese db/db mice were then given NRG1 for 8 weeks. Results. - Leptin serum concentrations were six times higher in C57BL/6JRJ mice treated with NRG1 than in the animals given saline. NRG1 treatment also reduced weight gain by 10% and food intakes by 15% compared with saline treatment, while energy expenditure remained unchanged. In db/db mice, serum leptin concentrations, weight gain, food intakes, energy expenditure and spontaneous physical activity were not altered by NRG1 treatment. Conclusion. - The decrease in food intakes and weight gain associated with NRG1 treatment in C57BL/6JRJ mice may be partly explained by increased leptin levels, whereas db/db mice were not affected by the treatment, suggesting resistance to NRG1 in this pathological state

Design and fabrication of a tunable InP-based VCSEL using a electro-optic index modulator

International audienceWe present the first vertical surface emitting laser (VCSEL) operating at 1.55-μm comprising a electro-optic modulator inside its cavity. This material consists of nematic liquid crystal dispersed in a polymer material (nano-PDLC). This first VCSEL exhibits a 10 nm tuning range and an excellent side-mode suppression ratio higher than 20 dB over the whole spectral range. The device is formed by a conventional InP-based active region with an epitaxial and a dielectric Bragg mirror. The nano-PDLC layer length, close to 6 μm, is in agreement with a tunable laser emission without mode-hopping. Another decisive advantage, compared to mechanical solutions, is the tuning response time which is close to a few 10 μs to scan the full spectral range, making this device appropriate for some access network functions. This first version is optically pumped and requires 170 volts to obtain a 10 nm tunability

Long-wavelength Vertical-Cavity Surface-Emitting Laser using an electro-optic index modulator with 10-nm tuning range

International audienceWe demonstrate an original approach to achieving a tunable 1.55-µm vertical-cavity surface-emitting laser. The tunability is based on an electro-optic index modulator using nano-sized droplets of liquid crystal as a phase layer. Such an approach can produce a robust and a low-cost device. A 10-nm tuning range with less than 170V applied voltage has been demonstrated. The device is formed by a conventional InP-based active region with an epitaxial and a dielectric Bragg mirror. This optically pumped device exhibits an excellent side-mode suppression ratio of higher than 20-dB over the whole spectral range

1.55-µm optically pumped tunable VCSEL based on a nano-polymer dispersive liquid crystal phase modulator

International audienceWe present a new approach to achieve tunability on a 1.55 μm vertical cavity surface emitting laser (VCSEL). Tunability is achieved thanks to an electro-optic index modulator. This electro-optic material consists in a n-PDLC phase layer introduced inside the VCSEL cavity. N-PDLC comprises nematic liquid crystal dispersed in a polymer material. This first VCSEL exhibits a 10 nm tuning range and an excellent side-mode suppression ratio higher than 20 dB over the whole spectral range. The device is formed by a conventional InP-based active region with an epitaxial and a dielectric Bragg mirror. The n-PDLC layer length, close to 6 μm, is in agreement with a tunable laser emission without mode-hopping. Another decisive advantage, compared to mechanical solutions, is the tuning response time which is close to a few 10 μs to scan the full spectral range, making this device appropriate for some access network functions. Voltage values are the main limiting factor, 170 Volts have been required to obtain 10 nm tunability, but material engineering is in progress to improve this point. We presented a first version of the device optically pumped, the next version will be electrically pumped as required for access network applications targeted here

60 GHz resonant photoreceiver with an integrated SiGe HBT amplifier for analog radio-over-fiber links

A photoreceiver is presented for remote antennas in the unlicensed 60 GHz band utilizing an amplifier designed to present a matched impedance to a photodiode. The photoreceiver offers 29 dB higher gain than a reference photodiode over a 3 dB bandwidth of 5.7 GHz while consuming 33.6 mW. It is demonstrated up to 20 Gbps over 5 km SSMF at 4 Gbaud using QAM32 with an RMS EVM of 11.5%

Integrated Optical-Wireless Interface and Detection

This chapter elaborates on the beneficial aspects and hardware implementations of incorporating ultradense WDM-PONs (UDWDM-PONs) with hybrid optical-wireless fronthaul links and fiber to the home applications. Simulation results on the synthesis of a low-cost and low-energy consumption optoelectronic unit within the future 5G base stations (BS) are presented. In addition, an advanced neural network is investigated capable of compensating for the linear and nonlinear effects induced by semiconductor optical amplifiers (SOA)

The chemical signatures underlying host plant discrimination by aphids

The diversity of phytophagous insects is largely attributable to speciation involving shifts between host plants. These shifts are mediated by the close interaction between insects and plant metabolites. However, there has been limited progress in understanding the chemical signatures that underlie host preferences. We use the pea aphid (Acyrthosiphon pisum) to address this problem. Host-associated races of pea aphid discriminate between plant species in race-specific ways. We combined metabolomic profiling of multiple plant species with behavioural tests on two A. pisum races, to identify metabolites that explain variation in either acceptance or discrimination. Candidate compounds were identified using tandem mass spectrometry. Our results reveal a small number of compounds that explain a large proportion of variation in the differential acceptability of plants to A. pisum races. Two of these were identified as L-phenylalanine and L-tyrosine but it may be that metabolically-related compounds directly influence insect behaviour. The compounds implicated in differential acceptability were not related to the set correlated with general acceptability of plants to aphids, regardless of host race. Small changes in response to common metabolites may underlie host shifts. This study opens new opportunities for understanding the mechanistic basis of host discrimination and host shifts in insects

Direct connection of uni-traveling-carrier photodiodes to antennas for frequency reconfigurable fiber-radio transmission in the Ka band

A compact photonically-driven wireless emitter based on a Uni-Traveling-Carrier photodiode (UTC-PD) which directly connects to a short asymmetrical inductive dipole (SAID) antenna is presented. The design exploits the dependence of the UTC-PD output impedance with the reverse bias voltage to provide maximum power transfer via conjugate impedance matching at different operative frequencies within the Ka band (26.5–40 GHz) with 6 dB antenna directivity and 1 GHz 10 dB return loss channel width. Electro-optical transmission measurements confirm that the photodiode responsivity is maintained throughout the whole voltage swing used for reconfigurability.Peer ReviewedPostprint (published version

Des produits issus d’animaux terrestres recevant une alimentation enrichie en DHA algal peuvent contribuer à la couverture des besoins en cet acide gras essentiel

Ce travail présente une méthode permettant d’augmenter la consommation en DHA de la population sans accroitre le prélèvement halieutique, grâce à la production de produits provenant d’animaux terrestres nourris avec des aliments contenant du DHA provenant de microalgues de culture et d’ALA provenant du lin extrudé. Après une identification des espèces fixant le DHA en quantité importante (pondeuse, lapins, poulet de chair), des essais réalisés sur ces animaux (21 sur pondeuses, 9 sur lapins, 6 sur poulets de chair) ont permis de déterminer les conditions d’enrichissement en DHA ainsi que les teneurs en cet acide gras que l’on peut atteindre dans ces produits. Ainsi, avec cette alimentation, le contenu en DHA des œufs est de 200 mg / 100 grammes soit 3,5 fois plus qu’un œuf standard; pour le lapin (par exemple, la gigolette), cette valeur est également de 200 mg / 100 grammes soit 10 fois plus qu’une viande de lapin standard; et pour le poulet de chair (par exemple, le blanc) 83 mg / 100 grammes soit 4 fois plus qu’une viande de poulet de chair standard. La plupart de ces produits peuvent alléguer « Riche en oméga 3 » ou « Source d’oméga 3 ». Ces différents aliments peuvent être associés dans des menus permettant d’atteindre les recommandations d’ingestion de DHA sans augmenter la consommation de poisson, améliorant ainsi la santé de la population et celle de la planète dans le respect des habitudes alimentaires.

A bloodâ based nutritional risk index explains cognitive enhancement and decline in the multidomain Alzheimer prevention trial

IntroductionMultinutrient approaches may produce more robust effects on brain health through interactive qualities. We hypothesized that a bloodâ based nutritional risk index (NRI) including three biomarkers of diet quality can explain cognitive trajectories in the multidomain Alzheimer prevention trial (MAPT) over 3â years.MethodsThe NRI included erythrocyte nâ 3 polyunsaturated fatty acids (nâ 3 PUFA 22:6nâ 3 and 20:5nâ 3), serum 25â hydroxyvitamin D, and plasma homocysteine. The NRI scores reflect the number of nutritional risk factors (0â 3). The primary outcome in MAPT was a cognitive composite Z score within each participant that was fit with linear mixedâ effects models.ResultsEighty percent had at lease one nutritional risk factor for cognitive decline (NRI â ¥1: 573 of 712). Participants presenting without nutritional risk factors (NRI=0) exhibited cognitive enhancement (β = 0.03 standard units [SU]/y), whereas each NRI point increase corresponded to an incremental acceleration in rates of cognitive decline (NRIâ 1: β = â 0.04 SU/y, P = .03; NRIâ 2: β = â 0.08 SU/y, P < .0001; and NRIâ 3: β = â 0.11 SU/y, P = .0008).DiscussionIdentifying and addressing these wellâ established nutritional risk factors may reduce ageâ related cognitive decline in older adults; an observation that warrants further study.Highlightsâ ¢Multiâ nutrient approaches may produce more robust effects through interactive propertiesâ ¢Nutritional risk index can objectively quantify nutritionâ related cognitive changesâ ¢Optimum nutritional status associated with cognitive enhancement over 3â yearsâ ¢Suboptimum nutritional status associated with cognitive decline over 3â yearsâ ¢Optimizing this nutritional risk index may promote cognitive health in older adultsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152935/1/trc2jtrci201911004.pd