Search

Self-reactive B cell progenitors are eliminated through central tolerance checkpoints, a process thought to be restricted to the bone marrow in mammals. Here, we identified a consecutive trajectory of B cell development in the meninges of mice and non-human primates. The meningeal B cells were located predominantly at the dural sinuses, where endothelial cells expressed essential niche factors to support B cell development. Parabiosis experiments together with lineage tracing showed that meningeal developing B cells were replenished continuously from hematopoietic stem cell (HSC)-derived progenitors via a circulation-independent route. Autoreactive immature B cells that recognized myelin oligodendrocyte glycoprotein (MOG), a central nervous system-specific antigen, were eliminated specifically from the meninges. Furthermore, genetic deletion of the Mog gene restored the self-reactive B cell population in the meninges. These findings identify the meninges as a distinct reservoir for B cell development, allowing in situ negative selection to ensure a locally non-self-reactive immune repertoire.

Reduced graphene oxide&ndash, epoxy grafted poly(styrene-co-acrylate) composites (GESA) were prepared by anchoring different amount of epoxy modified poly(styrene-co-acrylate) (EPSA) onto reduced graphene oxide (rGO) sheets through &pi, &ndash, &pi, electrostatic attraction. The GESA composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The anti-corrosion properties of rGO/EPSA composites were evaluated by electro-chemical impedance spectroscopy (EIS) in hydroxyl-polyacrylate coating, and the results revealed that the corrosion rate was decreased from 3.509 &times, 10&minus, 1 to 1.394 &times, 6 mm/a.

International audience; In apple, carbon source/sink relationships are assumed to affect fruit growth and floral induction and consequently tree flowering potential. Nevertheless, the effect of local variation of carbon source/sink relationships and distances within trees on these processes remains unclear. This study aimed at investigating the effect of distances between leaves, fruits and meristems on fruit size and floral induction. Experiments were performed on adult trees of the ‘Golden’ cultivar from 2015 until 2017 in the south of France. Thirteen treatments with different kinds of local leaf or fruit removal were set up in mid-June on trees previously managed to be either in low or high crop loads. Mean fruit weight and floral induction rate were evaluated in the different parts of the tree including defructified and defoliated parts.The floral induction rate was reduced on parts of the tree that were defoliated, whatever the defoliation treatment and, therefore, the distance to remaining leaves. Moreover, no impact of defoliations on floral induction was observed on not-defoliated parts of the trees. Both together, these results show a major impact of local source/sink conditions on floral induction. Fruit weight was reduced on the parts of the trees that were defoliated when leaf removal was performed on one side of the Y-Shape trees or on half of the branches. This decrease was also observed but to a lesser extent on defoliated shoots when leaf removal was performed randomly on half the shoots. This suggests that carbon fluxes came from the neighboring shoots to sustain fruit growth of non-leafy shoots. Fruit weight increased for trees subjected to fruit removal treatments, probably due to a flux of carbon from the parts of trees without fruits. This study confirms that source-sink relationships have a great impact on floral induction and fruit growth. Moreover it gives new knowledge on the scale of plant organization at which source-sink relationships affect these processes. These experiments will be used to calibrate a functional structural model built to simulate floral induction variability within trees.

This letter introduces a 4th order active RC complex filter with 1.5MHz center frequency and 1MHz bandwidth. The total harmonic distortion of the filter is less than −60dB and the image rejection ratio is greater than 60dB. A novel technique is also proposed in this letter to automatically adjust the variation of the time constant. The advantages of the proposed method are its high precision and simplicity. Using 5bits control words, the tuning error is less than ±1.6%.

A photo-polymerization initiator based on an imidazolium and an oxometalate, viz., (BMIm)2(DMIm) PW12O40 (where, BMIm = 1-butyl-3-methylimizodium, DMIm = 3,3'-Dimethyl-1,1'-Diimidazolium) is reported. It polymerizes several industrially important monomers and is recoverable hence can be reused. The Mn and PDI are controlled and a reaction pathway is proposed., Comment: Letter, 3 pages

This paper introduces a continuous time 5th order LP Butterworth OTA-C filter with cutoff frequency of 16 MHz. The automatic tuning system is implemented based on PLL with a special VCO. The simulation results show that the accuracy of the cutoff frequency is less than 1% and, even in the worst case, less than 3%.