Extended Wiener-Khinchin theorem for quantum spectral analysis

The classical Wiener-Khinchin theorem (WKT), which can extract spectral information by classical interferometers through Fourier transform, is a fundamental theorem used in many disciplines. However, there is still need for a quantum version of WKT, which could connect correlated biphoton spectral information by quantum interferometers. Here, we extend the classical WKT to its quantum counterpart, i.e., extended WKT (e-WKT), which is based on two-photon quantum interferometry. According to the e-WKT, the difference-frequency distribution of the biphoton wavefunctions can be extracted by applying a Fourier transform on the time-domain Hong-Ou-Mandel interference (HOMI) patterns, while the sum-frequency distribution can be extracted by applying a Fourier transform on the time-domain NOON state interference (NOONI) patterns. We also experimentally verified the WKT and e-WKT in a Mach-Zehnder interference (MZI), a HOMI and a NOONI. This theorem can be directly applied to quantum spectroscopy, where the spectral correlation information of biphotons can be obtained from time-domain quantum interferences by Fourier transform. This may open a new pathway for the study of light-matter interaction at the single photon level.Comment: 13 pages, 5 figure

Analysis and evaluation of a dynamic model for greenhouse lettuce growth

Aim of study: We analyzed and evaluated a nonlinear dynamic crop growth model called NICOLET B3, which can predict the dry and fresh matter content of lettuce in greenhouses. Area of study: Calibration was performed using experimental data obtained from the literature. The experiment was carried out in Saltillo, Mexico, and in a greenhouse in Beijing, China. Material and methods: We identified and discussed the feasibility of the studied model with multi-dimensional evaluation criteria. Meanwhile, a sensitivity analysis of input variables was conducted. After that, the least square identification method was used to calibrate the most sensitive parameter values to improve the robustness of the model. Main results: Results demonstrate that: i) the NICOLET B3 model is able to predict the fresh and dry matter production of lettuce with satisfactory accuracy verified (R2 = 0.9939 for fresh matter and R2 = 0.9858 for dry matter); ii) temperature has the most obvious impact on the model performance, compared with photosynthetically active radiation and CO2 concentration; iii) the model could perform well with only two inputs. Research highlights: Simulation results of evaluated NICOLET B3 model have a perfect goodness-of-fit. A method of calibrating parameters of the model and sensitivity analysis of three input variables of the model can facilitate its application

Plant adenylate cyclases have come full circle

In bacteria, fungi and animals, 3′-5′-cyclic adenosine monophosphate (cAMP) and adenylate cyclases (ACs), enzymes that catalyse the formation of 3′,5′-cAMP from ATP, are recognized as key signalling components. In contrast, the presence of cAMP and its biological roles in higher plants have long been a matter of controversy due to the generally lower amounts in plant tissues compared with that in animal and bacterial cells, and a lack of clarity on the molecular nature of the generating and degrading enzymes, as well as downstream effectors. While treatment with 3′,5′-cAMP elicited many plant responses, ACs were, however, somewhat elusive. This changed when systematic searches with amino acid motifs deduced from the conserved catalytic centres of annotated ACs from animals and bacteria identified candidate proteins in higher plants that were subsequently shown to have AC activities in vitro and in vivo. The identification of active ACs moonlighting within complex multifunctional proteins is consistent with their roles as molecular tuners and regulators of cellular and physiological functions. Furthermore, the increasing number of ACs identified as part of proteins with different domain architectures suggests that there are many more hidden ACs in plant proteomes and they may affect a multitude of mechanisms and processes at the molecular and systems levels

Interlayer Difference of Bilayer-Stacked MoS₂ Structure: Probing by Photoluminescence and Raman Spectroscopy

This work reports the interlayer difference of exciton and phonon performance between the top and bottom layer of a bilayer-stacked two-dimensional materials structure (BSS). Through photoluminescence (PL) and Raman spectroscopy, we find that, compared to that of the bottom layer, the top layer of BSS demonstrates PL redshift, Raman E 2 g 1 mode redshift, and lower PL intensity. Spatial inhomogeneity of PL and Raman are also observed in the BSS. Based on theoretical analysis, these exotic effects can be attributed to substrate-coupling-induced strain and doping. Our findings provide pertinent insight into film−substrate interaction, and are of great significance to researches on bilayer-stacked structures including twisted bilayer structure, Van der Waals hetero- and homo-structure

HNOXPred: a web tool for the prediction of gas-sensing H-NOX proteins from amino acid sequence

Summary: HNOXPred is a webserver for the prediction of gas-sensing heme-nitric oxide/oxygen (H-NOX) proteins from amino acid sequence. H-NOX proteins are gas-sensing hemoproteins found in diverse organisms ranging from bacteria to eukaryotes. Recently, gas-sensing complex multi-functional proteins containing only the conserved amino acids at the heme centers of H-NOX proteins, have been identified through a motif-based approach. Based on experimental data and H-NOX candidates reported in the literature, HNOXPred is created to automate and facilitate the identification of similar H-NOX centers across systems. The server features HNOXSCORES scaled from 0 to 1 that consider in its calculation, the physicochemical properties of amino acids constituting the heme center in H-NOX in addition to the conserved amino acids within the center. From user input amino acid sequence, the server returns positive hits and their calculated HNOXSCORES ordered from high to low confidence which are accompanied by interpretation guides and recommendations. The utility of this server is demonstrated using the human proteome as an example

Triptolide Inhibits Preformed Fibril-Induced Microglial Activation by Targeting the MicroRNA155-5p/SHIP1 Pathway

Evidence suggests that various forms of α-synuclein- (αSyn-) mediated microglial activation are associated with the progression of Parkinson’s disease. MicroRNA-155-5p (miR155-5p) is one of the most important microRNAs and enables a robust inflammatory response. Triptolide (T10) is a natural anti-inflammatory component, isolated from a traditional Chinese herb. The objective of the current study was to identify the role and potential regulatory mechanism of T10 in αSyn-induced microglial activation via the miR155-5p mediated SHIP1 signaling pathway. Mouse primary microglia were exposed to monomers, oligomers, and preformed fibrils (PFFs) of human wild-type αSyn, respectively. The expressions of TNFα and IL-1β, measured by enzyme-linked immunosorbent assay (ELISA) and qPCR, demonstrated that PFFs initiated the strongest immunogenicity in microglia. Application of inhibitors of toll-like receptor (TLR) 1/2, TLR4, and TLR9 indicated that PFFs activated microglia mainly via the NF-κB pathway by binding TLR1/2 and TLR4. Treatment with T10 significantly suppressed PFF-induced microglial activation and attenuated the release of proinflammatory cytokines including TNFα and IL-1β. Levels of IRAK1, TRAF6, IKKα/β, p-IKKα/β, NF-κB, p-NF-κB, PI3K, p-PI3K, t-Akt, p-Akt and SHIP1 were measured via Western blot. Levels of miR155-5p were measured by qPCR. The results demonstrated that SHIP1 acted as a downstream target molecule of miR155-5p. Treatment with T10 did not alter the expression of IRAK1 and TRAF6, but significantly decreased the expression of miR155-5p, resulting in upregulation of SHIP1 and repression of NF-κB activity, suggesting inhibition of inflammation and microglial activation. The protective effects of T10 were abolished by the use of SHIP1 siRNA and its inhibitor, 3AC, and miR155-5p mimics. In conclusion, our results demonstrated that treatment with T10 suppressed microglial activation and attenuated the release of proinflammatory cytokines by suppressing NF-κB activity via targeting the miR155-5p/SHIP1 pathway in PFFs-induced microglial activation