Results 41 to 50 of about 9,289,923 (301)

Gut microbiome and aging—A dynamic interplay of microbes, metabolites, and the immune system

FEBS Letters, EarlyView.
Age‐dependent shifts in microbial communities engender shifts in microbial metabolite profiles. These in turn drive shifts in barrier surface permeability of the gut and brain and induce immune activation. When paired with preexisting age‐related chronic inflammation this increases the risk of neuroinflammation and neurodegenerative diseases.
Aaron Mehl, Eran Blacher
wiley   +1 more source

Experimental and theoretical study of second and third harmonic generation in amorphous silicon

, 2022
We report contrasted experimental and theoretical results on second and third harmonic generation from an amorphous silicon nanolayer. We perform this study by analysing the harmonic optical signals generated when fs and ps pulses tuned at 800nm and ...
Scalora, Michael, Trull Silvestre, José Francisco, Vilaseca Alavedra, Ramon, Rodríguez Suñé, Laura, Cojocaru, Crina, Akozbek, Neset   +5 more
core   +1 more source

Frequency comb generation threshold via second-harmonic excitation in χ(2) optical microresonators

APL Photonics, 2020
We investigate the threshold of χ(2) frequency comb generation in lithium niobate whispering gallery microresonators theoretically and experimentally. When generating a frequency comb via second-harmonic excitation, also commonly known as second-harmonic
Jan Szabados, Boris Sturman, Ingo Breunig   +2 more
doaj   +1 more source

Design and analysis strategies for robust microbiome ageing research

FEBS Letters, EarlyView.
The gut microbiome changes with age and associates with age‐related morbidity and mortality, establishing it as a potential biomarker and intervention target for ageing. Realising this potential requires methodological rigour, yet distinguishing biological signals from methodological artefacts remains challenging across cohorts. This review provides an
Mark Olenik, İsmail Güderer, Yi Wang, Tayyaba Alvi, Prasoon Pandey, Handan Melike Dönertaş   +5 more
wiley   +1 more source

Random Quasi-Phase-Matched Second Harmonic Generation in Periodically Poled Lithium Tantalate

, 2009
We experimentally observed and explained bulk second harmonic generation via random quasi-phase-matching, derived from a periodically poled lithium tantalate sample with a randomly patterned mark-to-space ...
A. Pasquazi, Morandotti, R., STIVALA, Salvatore, BUSACCA, Alessandro, A. C. Busacca, R. Morandotti, S. Stivala, G. Assanto, Oliveri, L, Pasquazi, A, R. L. Oliveri, Assanto, G, S. Riva Sanseverino, RIVA SANSEVERINO, Stefano   +13 more
core   +1 more source

Second harmonic generation at a time-varying interface

Nature Communications
Time-varying metamaterials rely on large and fast changes of the linear permittivity. Beyond the linear terms, however, the effect of a non-perturbative modulation of the medium on harmonic generation remains largely unexplored.
Romain Tirole, Stefano Vezzoli, Dhruv Saxena, Shu Yang, T. V. Raziman, Emanuele Galiffi, Stefan A. Maier, John B. Pendry, Riccardo Sapienza   +8 more
doaj   +1 more source

Optical Second Harmonic Generation of Low-Dimensional Semiconductor Materials

Nanomaterials
In recent years, the phenomenon of optical second harmonic generation (SHG) has attracted significant attention as a pivotal nonlinear optical effect in research. Notably, in low-dimensional materials (LDMs), SHG detection has become an instrumental tool
Yue Fu, Zhengyan Liu, Song Yue, Kunpeng Zhang, Ran Wang, Zichen Zhang   +5 more
doaj   +1 more source

Microbiome‐blood–brain barrier interactions in aging — mechanisms and therapeutic potential

FEBS Letters, EarlyView.
Aging reshapes the gut microbiome (↓SCFA‐producing commensals; ↑pro‐inflammatory outputs), shifting circulating metabolites (↓SCFAs; ↑LPS, ↑TMAO, ↑PAA) that act at the BBB to increase nonspecific transcytosis, alter transport, and promote astrocyte reactivity, heightening brain vulnerability.
Daniel Cuervo‐Zanatta, Hari Baskar Balasubramanian, Amir Pasokh, Marietta Zille   +3 more
wiley   +1 more source

Conservation laws of generalized angular momentum by second-harmonic generation in underdense plasmas harmonic generation [PDF]

EPJ Web of Conferences
Light beams exhibit two intrinsic quantized degrees of freedom: spin angular momentum (SAM) and orbital angular momentum (OAM) whose manipulation enables precise control over the topological characteristics of electromagnetic fields. Recently, structured
Voisine Alexis, Béjot Pierre, Billard Franck, Marroux Hugo, Faucher Olivier, Hertz Edouard   +5 more
doaj   +1 more source

Second-harmonic generation of temporally low-coherence light

APL Photonics, 2020
In this Letter, we study the second-harmonic (SH) generation of temporally low-coherence light using the statistical optics method. By introducing the statistical characteristics of low-coherence light into the nonlinear coupled wave equation, we predict
Xiaohui Zhao, Lailin Ji, Dong Liu, Yanqi Gao, Daxing Rao, Yong Cui, Wei Feng, Fujian Li, Haitao Shi, Chong Shan, WeiXin Ma, Zhan Sui   +11 more
doaj   +1 more source