Ultrafast Surface Plasmonic Switch in Non-Plasmonic Metals

We demonstrate that ultrafast carrier excitation can drastically affect electronic structures and induce brief surface plasmonic response in non-plasmonic metals, potentially creating a plasmonic switch. Using first-principles molecular dynamics and Kubo-Greenwood formalism for laser-excited tungsten we show that carrier heating mobilizes d electrons into collective inter and intraband transitions leading to a sign flip in the imaginary optical conductivity, activating plasmonic properties for the initial non-plasmonic phase. The drive for the optical evolution can be visualized as an increasingly damped quasi-resonance at visible frequencies for pumping carriers across a chemical potential located in a d-band pseudo-gap with energy-dependent degree of occupation. The subsequent evolution of optical indices for the excited material is confirmed by time-resolved ultrafast ellipsometry. The large optical tunability extends the existence spectral domain of surface plasmons in ranges typically claimed in laser self-organized nanostructuring. Non-equilibrium heating is thus a strong factor for engineering optical control of evanescent excitation waves, particularly important in laser nanostructuring strategies

Nutritional value of defatted larvae meal and whole larvae from black soldier fly

Session 66, Théâtre 10International audienceBlack soldier fly (BSF) larvae is a novel protein source to feed poultry. However, only nutritional values for BSF mealsare available in the literature, whereas the use of whole larvae could be a promising strategy, for instance when usedas an environmental enrichment material. Thus, this study aimed to investigate the nutritional value of three differentBSF products: defatted larvae meal (LM) and whole larvae, either dried (DL) or fresh (FL). On a dry matter (DM)basis, crude protein (CP) and crude fat (CF) contents were respectively of 57 and 10% for LM vs 39 and 34% forwhole larvae. A total of 48 Ross 308 male boilers were randomly assigned to individual cages for a digestibility trial.Four treatments were used: a control diet (C), a LM diet containing 75% C + 25% LM and two larvae diets containing,on a DM basis, 75% C + 25% of FL or DL larvae. Whole larvae were distributed on top of pellets in the same feeder.For the three products (LM, DL, and FL), the metabolizable energy (AMEn) and the apparent total tract digestibility(ATTD) of DM, CF, CP, and gross energy (GE) were measured, as well as the standardised ileal digestibility (SID) ofamino acids (AA). The ATTD of DM, GE, and CP were significantly higher (P<0.001) for DL and FL compared to LM(DM: 83 vs 60%; GE: 85 vs 63%; CP: 68 vs 53%). TTAD of CF was significantly higher for DL (98.2%) comparedto LM (94.6%; P<0.01) and FL (95.7%; P<0.05). The AMEn was significantly lower for LM compared to DL/FL(2,730 vs 4,950 kcal/kg DM; P<0.001). The SID of all AA were significantly lower for LM (52-86%) compared toDL and FL (77-98%) with respective values of 84 vs 93% for lysine and 85 vs 95% for methionine+cysteine. Thesedifferences could be explained by the higher chitin content in LM, due to defatting process. At high concentration,chitin is indeed known to impair nutrients digestibility. These results provide the first data on the nutritional value ofwhole BSF larvae and confirm that BSF larvae are a highly digestible source of nutrients for poultry

Digestion dynamics in broilers fed rapeseed meal

Abstract Rapeseed proteins are described to be poorly digestible in chickens. To further identify some molecular locks that may limit their use in poultry nutrition, we conducted a proteomic study on the various chicken digestive contents and proposed an integrative view of the proteins recruited in the crop, proventriculus/gizzard, duodenum, jejunum, and ileum for digestion of rapeseed by-products. Twenty-seven distinct rapeseed proteins were identified in the hydrosoluble fraction of the feed prior ingestion. The number of rapeseed proteins identified in digestive contents decreases throughout the digestion process while some are progressively solubilized in the most distal digestive segment, likely due to a combined effect of pH and activity of specific hydrolytic enzymes. Fifteen chicken proteins were identified in the hydrosoluble proventriculus/gizzard content, including chymotrypsin-like elastase and pepsin. Interestingly, on the 69 distinct proteins identified in duodenum, only 9 were proteolytic enzymes, whereas the others were associated with homeostasis, and carbohydrate, lipid, vitamin and hormone metabolisms. In contrast, chicken proteins identified in jejunal and ileal contents were mostly proteases and peptidases. The present work highlights the relevance of using integrative proteomics applied to the entire digestive tract to better appreciate the protein profile and functions of each digestive segment

X-ray absorption K edge as a diagnostic of the electronic temperature in warm dense aluminum

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Electronic Structure Investigation of Highly Compressed Aluminum with K Edge Absorption Spectroscopy

The electronic structure evolution of highly compressed aluminum has been investigated using timeresolved $K$ edge x-ray absorption spectroscopy. A long laser pulse (500 ps, I$_L$ $\approx$ 8 X 10$^{13}$ W/cm$^2$) wasused to create a uniform shock. A second ps pulse (I$_L$ $\approx$ 10$^{17}$ W/cm$^2$) generated an ultrashort broadbandx-ray source near the Al $K$ edge. The main target was designed to probe aluminum at reshocked conditionsup to now unexplored (3 times the solid density and temperatures around 8 eV). The hydrodynamicalconditions were obtained using rear side visible diagnostics. Data were compared to ${ab}$ ${initio}$ and denseplasma calculations, indicating potential improvements in either description. This comparison shows thatx-ray-absorption near-edge structure measurements provide a unique capability to probe matter at theseextreme conditions and severally constrains theoretical approaches currently used