26 research outputs found
Quantum optical signal processing in diamond
Controlling the properties of single photons is essential for a wide array of
emerging optical quantum technologies spanning quantum sensing, quantum
computing, and quantum communications. Essential components for these
technologies include single photon sources, quantum memories, waveguides, and
detectors. The ideal spectral operating parameters (wavelength and bandwidth)
of these components are rarely similar; thus, frequency conversion and spectral
control are key enabling steps for component hybridization. Here we perform
signal processing of single photons by coherently manipulating their spectra
via a modified quantum memory. We store 723.5 nm photons, with 4.1 nm
bandwidth, in a room-temperature diamond crystal; upon retrieval we demonstrate
centre frequency tunability over 4.2 times the input bandwidth, and bandwidth
modulation between 0.5 to 1.9 times the input bandwidth. Our results
demonstrate the potential for diamond, and Raman memories in general, to be an
integrated platform for photon storage and spectral conversion.Comment: 6 pages, 4 figure
Storage and retrieval of ultrafast single photons using a room-temperature diamond quantum memory
We report the storage and retrieval of single photons, via a quantum memory,
in the optical phonons of room-temperature bulk diamond. The THz-bandwidth
heralded photons are generated by spontaneous parametric downconversion and
mapped to phonons via a Raman transition, stored for a variable delay, and
released on demand. The second-order correlation of the memory output is
, demonstrating preservation of non-classical
photon statistics throughout storage and retrieval. The memory is low-noise,
high-speed and broadly tunable; it therefore promises to be a versatile
light-matter interface for local quantum processing applications.Comment: 6 pages, 4 figure
Storage of polarization-entangled THz-bandwidth photons in a diamond quantum memory
Bulk diamond phonons have been shown to be a versatile platform for the
generation, storage, and manipulation of high-bandwidth quantum states of
light. Here we demonstrate a diamond quantum memory that stores, and releases
on demand, an arbitrarily polarized 250 fs duration photonic qubit. The
single-mode nature of the memory is overcome by mapping the two degrees of
polarization of the qubit, via Raman transitions, onto two spatially distinct
optical phonon modes located in the same diamond crystal. The two modes are
coherently recombined upon retrieval and quantum process tomography confirms
that the memory faithfully reproduces the input state with average fidelity
with a total memory efficiency of . In an
additional demonstration, one photon of a polarization-entangled pair is stored
in the memory. We report that entanglement persists in the retrieved state for
up to 1.3 ps of storage time. These results demonstrate that the diamond phonon
platform can be used in concert with polarization qubits, a key requirement for
polarization-encoded photonic processing
Punicic Acid a Conjugated Linolenic Acid Inhibits TNFα-Induced Neutrophil Hyperactivation and Protects from Experimental Colon Inflammation in Rats
BACKGROUND:Neutrophils play a major role in inflammation by releasing large amounts of ROS produced by NADPH-oxidase and myeloperoxidase (MPO). The proinflammatory cytokine TNFalpha primes ROS production through phosphorylation of the NADPH-oxidase subunit p47phox on Ser345. Conventional anti-inflammatory therapies remain partially successful and may have side effects. Therefore, regulation of neutrophil activation by natural dietary components represents an alternative therapeutic strategy in inflammatory diseases such as inflammatory bowel diseases. The aim of this study was to assess the effect of punicic acid, a conjugated linolenic fatty acid from pomegranate seed oil on TNFalpha-induced neutrophil hyperactivation in vitro and on colon inflammation in vivo. METHODOLOGY AND PRINCIPAL FINDINGS:We analyzed the effect of punicic acid on TNFalpha-induced neutrophil upregulation of ROS production in vitro and on TNBS-induced rat colon inflammation. Results show that punicic acid inhibited TNFalpha-induced priming of ROS production in vitro while preserving formyl-methionyl-leucyl-phenylalanine (fMLP)-induced response. This effect was mediated by the inhibition of Ser345-p47phox phosphorylation and upstream kinase p38MAPK. Punicic acid also inhibited fMLP- and TNFalpha+fMLP-induced MPO extracellular release from neutrophils. In vivo experiments showed that punicic acid and pomegranate seed oil intake decreased neutrophil-activation and ROS/MPO-mediated tissue damage as measured by F2-isoprostane release and protected rats from TNBS-induced colon inflammation. CONCLUSIONS/SIGNIFICANCE:These data show that punicic acid exerts a potent anti-inflammatory effect through inhibition of TNFalpha-induced priming of NADPH oxidase by targeting the p38MAPKinase/Ser345-p47phox-axis and MPO release. This natural dietary compound may provide a novel alternative therapeutic strategy in inflammatory diseases such as inflammatory bowel diseases
Global maps of soil temperature
Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world\u27s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (−0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications
Global maps of soil temperature
Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km² resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e., offset) between in-situ soil temperature measurements, based on time series from over 1200 1-km² pixels (summarized from 8500 unique temperature sensors) across all the world’s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in-situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications