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The dielectric properties of bismuth-based cubic pyrochlores strongly depend on the environment of the A-site ions, e.g. the Ni2+ ions doped into Bi1.5MgNb1.5O7 (BMN) pyrochlores for tailoring dielectric properties. Both BMN and Bi1.5NiNb1.5O7 (BNN) ceramics exhibit a cubic pyrochlore structure with preferential (222) planes. However, {442} reflections are observed in BNN pyrochlores, revealing an off-center displacement of A and O' ions. The dielectric constant of BNN pyrochlores is lower than that of BMN pyrochlores, besides BNN pyrochlores have a larger dielectric loss (0.002) than BMN pyrochlores (0.0007). Ni-doping results in a loose and flexible structure contributing positively to the dielectric tunability, besides creating a large amount of oxygen vacancies. The higher amount of oxygen vacancies increases the dielectric loss of BNN pyrochlores. However, BNN pyrochlores exhibit enhanced temperature stability, with a temperature coefficient of –57 ppm/oC, which is significantly better than that of BMN pyrochlores (–362 ppm/oC).

Photoetchable glasses (PEGs) are employed in packaging of radio frequency (RF) microsystems. However, their widescale adoption has been limited by intrinsic high dielectric losses. The present study reports results of systematic investigation of dielectric and thermodynamic properties of Barium (Ba) ion substituted Li–Al–Si-based PEGs. It is demonstrated that UV absorption characteristics remain largely unchanged upon Ba ion doping. Crystallization behavior of PEGs were determined by digital scanning calorimetry. After annealing at different temperatures, the structure and morphology of precipitated crystal phases were analyzed by x-ray diffraction and electron microscopy. Results reveal that the optimal annealing temperature was 565 °C, after which dielectric properties were measured to experience a dielectric constant and minimum dielectric loss of 4.7 and 3 × 10−3, respectively. Concomitantly, the influence of temperature on dielectric properties at constant frequency was investigated. Raman spectroscopy analyses exhibit that the incorporation of Ba ions do not participate in structural changes but rather dissociate within the glass network as network modifiers, influencing the dielectric properties of Ba-doped PEG. The improvement in dielectric and thermodynamic properties demonstrated here confirms the value of PEGs as preferred interposer materials in three-dimensional RF microsystem packaging.

Effects of Eu doping at the A site on the magnetic properties of the perovskite manganite La0.8-xEuxSr0.2MnO3(x = 0 and 0.05)polycrystalline samples were investigated in this paper. The polycrystalline La0.8-xEuxSr0.2MnO3 (x = 0,0.05)samples were synthesized using a traditional solid-phase reaction method. X-ray diffraction (XRD) analysis of the polycrystalline samples did not indicate any impurities, confirming that the samples are single phase. The magnetization vs. temperature curve (M-T), as well as the magnetization vs. magnetic field curves (M-H) of the two samples, show that both synthesized structures are paramagnetic in the high-temperature region, while near the Curie temperature (Tc), the material is ferromagnetic. The Tc of both samples, La0.8-xEuxSr0.2MnO3 with x = 0 and the Eu3+-doped sample with x = 0.05, increased to 283 K and 284 K, respectively. The hysteresis loops of the samples show insignificant coercive force and no remanence. The inverse magnetic susceptibility vs. temperature curves (χ−1-T, χ−1 = H/M) indicate that the Griffiths phase temperature remains unchanged, while the Curie temperature decreases. The trends confirm that $${Eu}^{3+}$$ doping changed the ferromagnetic coupling of the system. The average field model provides a good fit for the critical parameter response of both the parent and the doped synthesized material. At an applied field of 7 T, the change in magnetic entropy of the doped sample reaches its highest value at 4.19 J/kg·K, and the refrigeration efficiency is 445 J/kg. Our results show that the newly synthesized polycrystalline samples could be used as magnetic refrigeration materials.

In order to explore a superior washcoat material to give full play to the catalytic activity of perovskite active components on the monolithic catalysts, three novel types of LaCoO3/washcoat/cordierite monolith catalysts were prepared by a facile two-step procedure which employed the cordierite honeycomb ceramic as the monolith substrate, the nano-oxides (ZrO2, ɤ-Al2O3, TiO2) as the washcoat, and the perovskite of LaCoO3 as the active components. The blank cordierite, powdered LaCoO3, semi-manufactured monolithic catalysts (washcoat/cordierite), and manufactured monolithic catalysts (LaCoO3/washcoat/cordierite) were characterized by XRD, SEM, XPS, N2 adsorption-desorption, H2-TPR, and ultrasonic test, and their catalytic activities and catalytic stability were evaluated by the toluene oxidation test. The research results indicate that the nanoparticles coated on the cordierite substrate as the washcoat can give full play to the catalytic ability of the LaCoO3 active components and also showed high catalytic stability. However, the catalytic properties of the monolithic catalysts vary notably with the species of nano-washcoat. Among all the catalysts, the porous honeycomb surface structure, uniform distribution, high ratio of surface adsorbed oxygen, and strong reducing ability together give the LaCoO3/ZrO2/cordierite monolithic catalyst the highest catalytic activity on the oxidation of toluene at low temperature, which could be attributed to the excellent interactions of perovskite and nano-ZrO2 washcoat. Therefore, the nano-oxides, especially the nano-ZrO2, have a broad practical application potential for toluene oxidation at low temperature as the washcoat of perovskite-based monolithic catalysts.

Pb0.91Ba0.06La0.02(Zr0.95−xSnxTi0.05)O3 (PBLZST, x = 0.325, 0.35, 0.375, 0.4) thick films are prepared by solid-state reaction method and flow-casting method. Trace Ba2+ content is introduced to PLZST which is effective in narrowing the hysteresis loop, lowering the Curie temperature point, and improving the fatigue characteristics. Besides that, Zr:Sn ratios are adjusted to study its influence on the material’s energy storage characteristics. PBLZST ceramics with different Zr:Sn ratios are all in tetragonal perovskite structure. The increase of Sn4+ content promotes miniaturization of crystal grain and contributes to stability of antiferroelectric phase, together with enhances the phase transition field strength and breakdown field strength of PBLZST ceramics. The PBLZST ceramic has high energy storage efficiency, which is more than 80%. The maximum effective energy storage density of PBLZST ceramics at 1.94 J/cm3 is obtained when x = 0.35, and their energy storage efficiency is 81.9%, which confirms that they are the potential materials in the pulse energy storage components.

With the development of image recognition technology, face, body shape, and other factors have been widely used as identification labels, which provide a lot of convenience for our daily life. However, image recognition has much higher requirements for image conditions than traditional identification methods like a password. Therefore, image enhancement plays an important role in the process of image analysis for images with noise, among which the image of low-light is the top priority of our research. In this paper, a low-light image enhancement method based on the enhanced network module optimized Generative Adversarial Networks(GAN) is proposed. The proposed method first applied the enhancement network to input the image into the generator to generate a similar image in the new space, Then constructed a loss function and minimized it to train the discriminator, which is used to compare the image generated by the generator with the real image. We implemented the proposed method on two image datasets (DPED, LOL), and compared it with both the traditional image enhancement method and the deep learning approach. Experiments showed that our proposed network enhanced images have higher PNSR and SSIM, the overall perception of relatively good quality, demonstrating the effectiveness of the method in the aspect of low illumination image enhancement.

Solar-driven nitrogen fixation is a promising clean and mild approach for ammonia synthesis beyond the conventional energy-intensive Haber-Bosch process. However, it is still challenging to design highly active, stable, and low-cost photocatalysts for activating inert N2 molecules. Herein, we report the synthesis of anatase-phase black TiO2-xSy nanoplatelets enriched with abundant oxygen vacancies and sulfur anion dopants (VO-S-rich TiO2-xSy) by ion exchange method at gentle conditions. The VO-S-rich TiO2-xSy nanoplatelets display a narrowed bandgap of 1.18 eV and much stronger light absorption that extends to the near-infrared (NIR) region. The co-presence of oxygen vacancies and sulfur dopants facilitates the adsorption of N2 molecules, promoting the reaction rate of N2 photofixation. Theoretical calculations reveal the synergistic effect of oxygen vacancies and sulfur dopants on visible-NIR light adsorption and photoexcited carrier transfer/separation. The VO-S-rich TiO2-xSy exhibits improved ammonia yield rates of 114.1 μmol g-1 h-1 under full-spectrum irradiation and 86.2 μmol g-1 h-1 under visible-NIR irradiation, respectively. Notably, even under only NIR irradiation (800-1100 nm), the VO-S-rich TiO2-xSy can still deliver an ammonia yield rate of 14.1 μmol g-1 h-1. This study presents the great potential to regulate the activity of photocatalysts by rationally engineering the defect sites and dopant species for room-temperature N2 reduction.

The dynamic properties of one kind of Inter-Connected Hydro-Pneumatic Struts (IC HPS), which is designed based on the developed double-gas-chamber compacted Hydro-Pneumatic Struts (HPS) integrating double inner gas chambers, will be investigated in this research. Comparing with the traditional IC HPS designs based on single gas chamber compacted HPS, the proposed IC HPS can postpone the force distortion, and then increase the working envelop, provide good stiffness performance and be stable in both In-Phase and Out-of-Phase working condition. The equation of motion of the proposed IC HPS will be derived firstly. And then based on the established dynamic model, the related simulating model will be established utilizing the AMEsim software, and the validity of the established simulating model will be verified on the basis of experimental data and available literatures. The validity and performance of the proposed IC HPS will be verified and investigated through comprehensive comparison with traditional IC HPS designs. Finally, the detailed sensitivity analysis of the essential design parameter of the proposed IC HPS will be presented to illustrate the advantage of the proposed IC HPS design.

Photoetchable glasses (PEGs) have been widely used in three-dimensional integrated circuits as interposers. However, the high costs associated with laser through-hole technology have limited their utilization in high-frequency circuitry and packaging. Ultraviolet lithography may reduce the cost and improve through-hole properties allowing PEGs to become a preferred practice and lend them to wider usage. Herein, we investigate the viability of PEGs by systematically studying the structural, compositional, and morphological properties of their through-hole composite structures as a function of several key process parameters including exposure energy and annealing conditions. Results indicate that both exposure energy and annealing temperature and duration have compensating effects. Optimized through-glass vias (TGVs) were determined to result from an annealing temperature of 560 °C, an annealing time of 60 min, and an exposure energy of 6 J/cm2. Metallization of through-holes was carried out using magnetron sputtering of an adhesion layer of Ti followed by a Cu layer. The morphology and composition of through-hole metallization, analyzed by electron microscopy and energy dispersive X-ray spectroscopy, revealed surfaces to have sharp, well-defined edges with smooth surfaces. The proposed PEG interposer processing methodologies described here offer renewed optimism for the efficient fabrication of channels and through-vias for microfluidic and integrated circuits and other three-dimensional electronic and hybrid systems.

Relatively high dielectric loss often limits the widespread utilization of photoetchable glasses (PEG) in three-dimensional system packaging. Herein, we present the influence of B-doping on network structures and dielectric properties of a Li-Al-Si-based PEG. The addition of B is found to markedly reduce the dielectric losses over the VHF-UHF bands making these PEGs more suitable for applications. Moreover, the effect of UV exposure on structural transformations is studied by X-ray diffraction and Raman spectroscopy. At a B2O3 additive content of 2 wt.-%, the average dielectric loss and dielectric constant are found to be 0.005 and 4.57, respectively, before UV exposure. However, these values decrease to 0.0015 and 3.65, respectively, after UV exposure and thermal annealing. The annealing temperature of PEG can be adjusted based on crystallization temperature since the stability of the boron trihedra are higher than that of the silicon-oxygen tetrahedra. Overall, it is determined that the use of B2O3 as an additive is effective in altering the dielectric properties of photosensitive glass making the PEGs more suitable for low loss three-dimensional system packaging for use over VHF and UHF bands.

The Stegana (Steganina) shirozui species group is mainly distributed in East Asia. In the present study, the molecular phylogeny of the S. shirozui group was investigated based on mitochondrial (COI and ND2) and nuclear (28S rRNA) markers. The resulting trees support the S. shirozui group as monophyletic and indicate that in this group, species associated with closer affinities show higher structural homogeneity in male genitalia. Molecular species delimitation assess most species limits and recognize four new species in the S. shirozui group from south-west China: S. alianya sp. nov., S. diodonta sp. nov., S. zebromyia sp. nov. and S. zopheria sp. nov. One new synonym was also recognized. Additionally, three typical male genital characters of the S. shirozui group were placed on the molecular phylogenetic framework. The outcome of both divergence-time estimation and ancestral area reconstruction suggests that the S. shirozui group likely originated in south-west China in the Middle Miocene.

For heat-transfer-controlled or diffusion-controlled phase transformation simulations, the movement of the interface between different phases needs to be determined, which is commonly called the Stefan problem. Various numerical methods have been developed for this and the movement of the interface is conventionally calculated by a flux balance equation, which is usually called the Stefan condition equation. However, mass conservation errors have been reported in the literature for some of the numerical methods. In this research, a control volume method based interface movement equation was proposed to achieve mass conservation during calculation. The obtained maximum relative mass conservation error for the new interface movement equation is less than 10−13 and the total mass is constant to the machine precision. This is much smaller than that of the Stefan condition discrete equation, which is in the order of 10−2. It was also found that the mass conservation accuracy of the numerical methods partly depends on the choice of the interface movement equation. The mass change term in the Stefan condition discrete equation is only a part of the whole mass change during interface movement, leading to the mass non-conservation found in the literature. In contrast, the piecewise integration treatment in the proposed interface movement equation in this research gives a more accurate mass change description during the interface movement. The correctness of the proposed interface movement equation was also proved by a comparison with the analytical solutions.

In order to study the influence of substrates on the structure and properties of deposited functional nanocomposite film, polyester fabrics with different structures were used as substrates, metal ...

Ghost imaging is a fascinating framework which constructs the image of an object by correlating measurements between received beams and reference beams, none of which carries the structure information of the object independently. Recently, by taking into account spacetime duality in optics, computational temporal ghost imaging has attracted attention. Here, we propose a novel Fourier temporal ghost imaging (FTGI) scheme to achieve single-shot nonreproducible temporal signals. By sinusoidal coded modulation, ghost images are obtained and recovered by applying Fourier transformation. For demonstration, non-repeating events are detected with single-shot exposure architecture. It is shown in experimental results that the peak signal-to-noise ratio (PSNR) of FTGI is significantly better (13 dB increase) than traditional temporal ghost imaging in the same condition. In addition, by using the obvious physical meaning of the Fourier spectrum, we show some potential applications of FTGI, such as frequency division multiplexing demodulation in the visible light communications.

Superionic conductors with ionic conductivity on the order of mS cm-1 are expected to revolutionize the development of solid-state batteries (SSBs). However, currently available superionic conductors are limited to only a few structural families such as garnet oxides and sulfide-based glass/ceramic. Interfaces in composite systems such as alumina in lithium iodide have long been identified as a viable ionic conduction channel, but practical superionic conductors employing the interfacial conduction mechanism are yet to be realized. Here we report a novel method that creates continuous interfaces in the bulk of composite thin films. Ions can conduct through the interface, and consequently, the inorganic phase can be ionically insulating in this type of bulk interface superionic conductors (BISCs). Ionic conductivities of lithium, sodium, and magnesium ion BISCs have reached 1.16 mS cm-1, 0.40 mS cm-1, and 0.23 mS cm-1 at 25 °C in 25 μm thick films, corresponding to areal conductance as high as 464 mS cm-2, 160 mS cm-2, and 92 mS cm-2, respectively. Ultralow overpotential and stable long-term cycling for up to 5000 h were obtained for solid-state Li metal symmetric batteries employing Li ion BISCs. This work opens new structural space for superionic conductors and urges for future investigations on detailed conduction mechanisms and material design principles.

We propose and demonstrate a rectangular optical lattice filter with reconfigurable bandwidth and wavelength. The proposed reconfigurable rectangular lattice filter consists of three-stage cascaded ring-assisted Mach-Zehnder interferometers (RAMZIs), and each RAMZI unit serves as an approximate optical elliptical filter with optimized shape factor. The scheme and design principle are presented with the method of zero-pole theory. As a proof of concept, the proposed structure is fabricated on the Si3 N4 waveguide platform. In the experiment, the 3-dB bandwidth of the proposed filter can be continuously tuned from 14.1 GHz to 4.1 GHz, maintaining a rectangular transmission response, and the wavelength can also be continuously tuned. This reconfigurable rectangular optical lattice filter shows the potential in many practical applications for reconfigurable optical signal processing due to flexibility and reconfigurability.

Photoetchable glasses (PEG) are widely used as interposers in radio frequency electronic systems. However, high dielectric losses limit the utilization of PEGs in three-dimensional integrated microsystems. Herein, the internal structure of PEGs is shown to be altered by the addition of Al2O3 and its influence on dielectric properties systematically studied by X-ray diffraction, Raman spectroscopy and FT-infrared spectroscopy (FTIR). The Al2O3 content significantly influences the ring structure and an amount equal to 4 wt% results in a high degree of crystallinity and phase purity of lithium metasilicate. Lastly, a dielectric constant of 5.1 and dielectric loss of 3 × 10-3 were obtained at 1 GHz, which is attributed to weakened structural vibrations, without loss to attractive etching properties.

Tb1–xTmxFeO3 (x = 0.00, 0.15, 0.25) polycrystalline series were synthesized using a solid-state reaction. Our results show that all three prepared samples are in a distorted orthogonal structure and their space group is p b n m . When the Tm3+ doping amount increases, the characteristics of the spin-flip of the sample decreases following an initial increase at the beginning; the antiferromagnetic property almost reaches zero; the magnetization decreases at the beginning but increases later on. The maximum magnetic entropy change and magnetic refrigeration effect RCP are reduced at varying degrees. Under a 7 T magnetic field, the maximum magnetic entropy change, ΔSmax, for the three samples of Tb1–xTmxFeO3 with x = 0.00, 0.15, 0.25 is 13.78, −9.28, and 10.69 J/(K·kg), respectively; the magnetic refrigeration capacity (RCP) is 316.85, 175.2, and 297.60 J/kg, respectively. In summary, doping with the element Tm reduces ΔSmax and RCP of the sample. Since the maximum magnetic entropy change and the cooling capacity for the three samples are relatively large, they can be used as an alternative for magnetic refrigerants.

Magnetocaloric effect and critical exponent analysis of La0.8-xEuxSr0.2MnO3 (x = 0, 0.075) manganites synthesized via a solid state reaction route have been explored. Rietveld analysis indicates that crystal structure of La0.8-xEuxSr0.2MnO3 (for x = 0.0) is in orthorhombic structure with pbnm space group. After the substitution of Eu, the structure changes from orthorhombic (for x = 0.0) to rhombohedral structure for (x = 0.075) with R 3 ¯ c space group. The TC is 287 K and 271 K for the samples with x = 0.000 and x = 0.075, respectively, and the magnetic entropy change is 2.76J K − 1•kg−1 for x = 0.000 and 3.94J K − 1•kg−1 for x = 0.075. The real cooling power (RCP) is 447.7 J•kg−1 for the sample with x = 0.000 and 445 J•kg−1 for the samples with x = 0.075. Both samples show a second order phase transition in the vicinity of TC. The critical exponents were determined using modified Arrott plots and Kouvel-Fisher methods. The critical behavior of these two samples fit best with the mean field model.

40CrNi steel is a low alloy steel with medium hardenability and has been widely used in the manufacturing of crankshafts, wind turbine forgings, etc. As forging is usually involved in the manufacturing of these components, optimization of the hot deformation process of 40CrNi steel is quite critical. Towards this, the prediction of flow stress and the determination of optimal processing parameter windows are of great importance. In this research, isothermal uniaxial hot compression tests were carried out for 40CrNi steel with true strain rates of 0.01, 0.1, 1, 10 and 30 s−1 and temperatures of 850–1200 °C. Both the strain compensated hyperbolic sine constitutive equation and the modified Johnson-Cook model were adopted to predict the flow stress curves, with average absolute relative errors of 0.034 and 0.061, respectively. Processing maps of the tested steel were constructed to determine the optimal deformation parameter windows, and the characteristics of the prior austenite microstructure generally correspond very well to the processing map established. Furthermore, different processing map construction methods were compared and it was found that power-dissipation efficiency maps strongly rely on the σ- e ˙ relationship. Assuming a certain type of constitutive equations leads to monotonic efficiency value patterns. Calculation methods based on experimental results are helpful to reflect the meaningful information carried by the experimental σ- e ˙ relationships.

Higher dimensional optical imaging has seen remarkable growth in the past decade. As a representative method, multiplexed structured illumination (MSI) has been widely introduced for its ultra-high resolution of high-dimensional information. In this letter, an imaging framework for recovering higher dimensional image data, which terms quadrature multiplexed structured illumination (QMSI), is proposed and demonstrated. QMSI incorporates the illumination pattern spatial phase information as a new parameter into the encoding process. This strategy can double the frequency spectrum utilization without any overhead compared to MSI, which means it can double the image sequence depth or image spatial resolution. As a proof of concept, we demonstrate the performance of QMSI by experiments on multispectral imaging.

Phylogenetic relationships of the two largest species groups in the genus Amiota [the Amiota alboguttata group (29 known and six new species) and the Amiota basdeni group (17 known and three new species)] were reconstructed using two mitochondrial gene sequences (COI and ND2). The paraphyly of the A. alboguttata group was identified based on molecular evidence. The monophyletic A. basdeni group is found to be nested in the A. alboguttata group, rendering the latter paraphyletic. Automatic barcode gap discovery and Bayesian phylogenetics and phylogeography methods were used to assess species limits of the A. alboguttata and A. basdeni groups. The results indicate that most analysed species could be delimited clearly, including nine new species (Amiota beama sp. nov., Amiota cyclophylla sp. nov., Amiota flormontana sp. nov., Amiota obtusa sp. nov., Amiota planiceps sp. nov., Amiota scrobicula sp. nov., Amiota jianjuni sp. nov., Amiota tentacula sp. nov. and Amiota xinglaii sp. nov.), except for some closely related morphospecies. Furthermore, based on the highly biased distributions of these two groups, southwestern China is hypothesized to be a possible centre of origin and diversification for Amiota in East Asia.

We report the rational design and implementation of a new class of gel guest-assisted, ionic covalent organic framework (COF) membranes that exhibit superior H+ conduction. The as-synthesized COFs are postmodified via a lithiation (or sodiation) treatment. The hydrophilic Li or Na ions in the COFs form a dense and extensive hydrogen-bonding network of H2O molecules with mobile H+ at the periphery, thereby transforming COFs into H+ conductors. Then, the ionic COFs are assembled into a flexible H+ conductor membrane via a gelation process, where the organic gel provides both mechanical strength and additional H+ carriers for fast H+ conduction. The final COF-based membrane exhibits an excellent H+ conductivity of 1.3 × 10-1 S cm-1 at 313 K and 98% relative humidity, which are the highest values of the COF-based H+ conductors reported until now and are even comparable with those of the typical commercial Nafion membrane. We anticipate that the two-in-one strategy would open up a porous COF-driven new molecular framework and membrane architectural design/opportunity for development of next-generation ionic conductors.

Optical phased array (OPA) can achieve beam steering by controlling the phase distribution of each channel. In traditional OPA, 2π phase tuning range is required to achieve beam steering. However, large phase tuning range can lead to large size, high power consumption, high operating voltage and low speed. Moreover, the performance of OPA with small phase tuning range, such as metasurface OPA, degrades greatly in traditional method. Here, we propose a design method of OPA with insufficient phase tuning range (10 dB side-mode suppression ratio (SMSR) can be achieved with any phase tuning range.

Solid electrolyte is the key component of any practical solid-state batteries. Although inorganic Li3PS4 electrolyte has been widely studied, this material is highly unstable in air, reactive towards Li metal, and difficult to process. These undesirable features have limited its application in solid state lithium batteries. In this work, a hybrid solid state electrolyte composed of β-Li3PS4 and poly(glycidyl methacrylate) is prepared through a controlled interfacial reaction between the polymer and the Li3PS4. The resulting hybrid electrolyte shows a good processability, i.e. it can be processed through simple slurry coating rather than conventional cold pressing or high-temperature sintering techniques. Furthermore, it exhibits improved air stability and decreased interfacial resistance with metallic lithium as compared with pure Li3PS4 electrolytes. More interestingly, this hybrid electrolyte exhibits a high ionic conductivity of 1.8 × 10−4 S/cm at room temperature, which is even slightly higher than the ionic conductivity of the pure β-Li3PS4. The new type of hybrid electrolyte will be highly promising for future applications in solid state batteries.

Host defense peptides (HDPs) constitute a large group of natural broad-spectrum antimicrobials and an important first line of immunity in virtually all forms of life. Specific augmentation of synthesis of endogenous HDPs may represent a promising antibiotic-alternative approach to disease control. Previously, we purified and identificated a Novel Antimicrobial Host Defense Peptide from a histone of Rabbit sacculus rotundus, and termed this Peptide RSRAH, which could promoted cellular immune function in immunosuppressed mice and protected mice from E. coli challenge (Chen in Int J Pept Res Ther 2015, 2018). In the present study, we further revealed that RSRAH expression in the sacculus rotundus is significantly higher in adult rabbits than in aging rabbits. And RSRAH is highly expressed in immune-related tissues. Furthermore, feed supplementation with 0.1% and 0.2% Atractylodes macrocephala polysaccharide, recognized as an ideal immunopotentiator, led to a significant increase in RSRAH gene expression in the Rabbit sacculus rotundus. Collectively, it was hypothesized that RSRAH may play an important role in the immune system of rabbits.

Li2O-Al2O3-SiO2 (LAS) photostructurable glasses (PSGs) are promising substrate materials with excellent three-dimensional shaping control. In this study, we prepared SrO-doped LAS-PSGs with different SrO content. The effect of SrO content on the dielectric and mechanical properties of the LAS-PSGs was investigated by deconvoluting (four-component) their Raman bands. The LAS-PSG sample with 1 wt% SrO exhibited enhanced mechanical properties: the enhanced surface micro-hardness of 568.20 HV, and the improved flexural strength of 157.23 MPa while maintaining a low dielectric loss of 4.1 × 10−3. These improvements of mechanical properties can be attributed to the increased relative fraction of Q3 units (Qn: n bridging oxygen bonds in a [SiO4] tetrahedral unit) in this sample. This is due to Q3 units being able to enhance the network structure of LAS-PSGs with little effect on [SiO4] tetrahedral units connections.

Calculating the spectral function of two dimensional systems is arguably one of the most pressing challenges in modern computational condensed matter physics. While efficient techniques are available in lower dimensions, two dimensional systems present insurmountable hurdles, ranging from the sign problem in quantum Monte Carlo (MC), to the entanglement area law in tensor network based methods. We hereby present a variational approach based on a Chebyshev expansion of the spectral function and a neural network representation for the wave functions. The Chebyshev moments are obtained by recursively applying the Hamiltonian and projecting on the space of variational states using a modified natural gradient descent method. We compare this approach with a modified approximation of the spectral function which uses a Krylov subspace constructed from the "Chebyshev wave-functions". We present results for the one-dimensional and two-dimensional Heisenberg model on the square lattice, and compare to those obtained by other methods in the literature., Comment: 8 pages, 5 figs

Inspired by the concept of system-in-a-package (SiP) in electronics, here we report a hybrid microwave photonic receiver prototype by integrating lithium niobate (LiNbO3) dual-parallel phase modulators with silicon nitride (Si3N4) integrated tunable microring filters. In particular, we experimentally characterize these employed key elements and evaluate the down-conversion performance of RF signals from 4-20 GHz to the intermediate frequency. With the advantages of the tunable microwave photonic signal filtering, uniform system performance within a broad operation bandwidth, and low SWaP, the demonstrated hybrid microwave photonic receiver module shows a potential setup to satisfy the requirements of wireless communication systems, phased-array radar systems, and electronic warfare.

(1 − x)BaTiO3–x (Bi2O3, Sm2O3) (BT–BS, x = 0.1, 0.15, 0.2, 0.25, 0.3) ceramics were prepared by traditional solid phase sintering method. The effects of structure, temperature and frequency on dielectric tunability, ferroelectric relaxation characteristics and dielectric loss were analyzed. Phase analysis by XRD showed that the main crystal phase was BaTiO3 perovskite structure, in addition to the second phase of Bi7.68Ti0.32O12.16 was also generated. The surface morphology was analyzed by SEM, it was found that the generation of second phase and the porosity decreased with the increase of BS content. At the same time, the increase of Sm3+ promoted the growth of crystal particles. The dielectric constant-temperature curve gradually became flat, which indicated that the relaxation characteristics of the ferroelectric ceramic gradually appear. The Curie temperature point gradually decreased with the doping of the BS. The relationship between dielectric loss and temperature showed that the dielectric loss increased when the temperature over 150 °C. This is mainly related to relaxation polarization at high temperature. Under the action of DC applied electric field and room temperature, dielectric loss and dielectric constant decreased with the increase of BS content. Meanwhile, dielectric tunability was improved when composite phase appeared. The maximum dielectric tunability (E = 50 kV/cm, 10 kHz) was 58.4% at x = 0.25.

The dielectric and energy-storage properties of (Pb0.97−xSrxLa0.02)(Zr0.675Sn0.285Ti0.04)O3 (x = 0, 0.005, 0.01, 0.015) bulk ceramics and thick films were investigated. All samples are orthorhombic perovskite antiferroelectric phase and have dielectric temperature relaxation property. Sr-dopant can improve the stability of the antiferroelectric phase and increase the phase transition field, but cause a decrease in dielectric constant. Thick films have a higher maximum tolerable external electric field strength than bulk ceramics. Compared with undoped thick film, the forward phase transition field and the backward phase transition field of the 1.5% doped thick film increased by 32% and 27%, respectively. The maximum polarization of the 1.5% doped thick film is decreased by 17%. The largest recoverable energy-storage density was obtained in thick film with 1% Sr doping. The largest recoverable energy-storage density is 2.77 J/cm3, which is 9.4% higher than the undoped thick film ceramic and 477% higher than the bulk ceramic with 1% Sr doping. The high energy storage density indicates that the obtained thick film is promising for pulsed power capacitors.

The interference of co-existing substances often causes trouble in the analysis of trace metal ions in complex samples, even for highly selective sensors. For this reason, an instant and inexpensive fluorescence sensor array for discrimination of heavy metal ions in complex samples was developed. The sensor array was constructed using four kinds of Mn doped ZnS quantum dots (Mn: ZnS QDs), which were facilely modified with N-Acetyl-cysteine, citric acid, mercaptopropionic acid and triammonium-N-dithiocarboxyiminodiacetate, respectively. For each metal ion, quantitative calibration curves were obtained with the concentration level ranging from 10 to 100 pg/mL (R2 > 0.96). Due to the different quenching effect for Cu, Hg, Ag and Cd on various QDs, the sensor array exhibited a unique pattern of fluorescence variations at a low concentration of 30 pg/ml and can be discriminated successfully by principal component analysis (PCA). The contribution of individual sensors within the array was demonstrated and the obtained information was used to design sensor arrays with two and three sensor elements. The sensor array was also applied to identify the metal ions in unknown mixtures, containing single, binary, ternary and quaternary constitutions. Linear discriminant analysis (LDA) showed that the samples could be well recognized and distinguished. The sensor array was finally applied in water samples with three different concentrations, indicating the co-existing substances rarely influenced discriminatory capacity of the sensor array. Compared to instrumental analysis, this fluorescence sensor array-based method has proven to be more convenient since the nanoparticles can be prepared flexibly according to the property of the target.

Toughness and tensile strength are important mechanical properties of polymers. However, it is generally very challenging to improve the toughness without an obvious decrease in the tensile strength, and vice versa, which greatly limits the applications of polymers. Here we developed a novel hydrogen bonding-based self-assembly technology for melt blending polymers to achieve a notable improvement in toughness without an obvious decrease in the tensile strength. Thermoplastic polyurethane (TPU)/polyamide 6 (PA6) blend was selected a model composite and its elongation at break increased significantly from 1150% (0 wt% PA6) to 1350% (7.5 wt% PA6) and 1375% (10 wt% PA6), without an obvious decrease in the tensile strength. We deeply investigated the relationship between microcosmic self-assembly and macroscopic mechanical properties in polymer melt blends. It was found that the hard and soft segment groups (urethane and ester) of TPU form new hydrogen bonds with the amide group of PA6 through hydrogen-bonded self-assembly during the melt blending process, while the intrinsic hydrogen bonding structure of TPU was obviously shielded and weakened. As a result, the TPU/PA6 melt blends showed a notable improvement in toughness without an obvious decrease in the tensile strength. Since most previous self-assembly studies were carried out in solution and there was little work focused on the industrial convenient melt blending method, our study paves the way for further studies on both theoretical studies and practical applications of polymer blends.

Barium strontium titanate (BaxSr1–xTiO3, BST) thin films have large dielectric constant, low dielectric loss, especially the high dielectric tunability, which make them prospective candidates for microwave tunable applications. Resent developments in BST thin films by doping modification are reviewed. The A-site doping, B-site doping, and both sites codoping modifications are summarized and analyzed, respectively. The comparison of dielectric properties and microstructure of the BST thin films with different sites doping modifications is critically analyzed. The single A-site or B-site doping modification cannot obtain the BST thin films with balanced enhancement of the dielectric properties. However, the different elements codoping in both A-site and B-site of BST thin films is demonstrated to be an effective method to achieve balanced dielectric property optimization.

Polycrystalline samples of La0.9−xEuxSr0.1MnO3 (x = 0.00, 0.05) were prepared using the standard solid-state reaction method. The effects of Eu3+ doping on the magnetic properties, magnetic entropy changes, and critical behaviors of La0.9Sr0.1MnO3 polycrystalline samples were systematically investigated. Preformed cluster phases were present in both samples in the temperature ranges of 118–326 K and 121–329 K, respectively. Additionally, near the Curie temperature (TC), the samples exhibited a second-order transition. The critical behaviors of the two samples were best fitted with the mean field model. The maximum magnetic entropy changes $$ \left| {\Delta S_{\text{M}} } \right| $$ of the two tested samples at 7 T near TC were 2.76 J K−1 kg−1 and 2.53 J K−1 kg−1, respectively; in addition, their relative cooling power was 425.28 J kg−1 and 354.93 J kg−1, respectively. The maximum magnetic entropy change calculated from the fitted data was in close agreement with the experimental data. These results indicate that the samples have the potential to realize magnetic refrigeration in the high-temperature regime (T > 77 K).

The large-scale hydraulic fracturing technology is commonly employed to significantly improve oil recovery in shale. An exceptional phenomenon from many field tests is worthy of attention that the majority of fracturing fluid (mainly water) does not return to the surface during hydraulic fracturing, but flows into shale matrix. As a consequence of this phenomenon, oil-water two-phase flow would happen. However, the fluid transportation in nano-pores is different from that of the conventional sandstone reservoirs. To understand oil-water two-phase flow in shale, an integrated pore network model (PNM) framework including network construction and flow simulation is developed. In the network construction, combined with a pore-size distribution (PSD) curve of shale system, a shale multiscale random pore network model is proposed, where organic pores and inorganic pores can be distinguished appropriately. In the flow simulation, considering that the traditional Hagen-Poiseuille equation may not be applicable in shale system, new bulk fluid and corner film flow models with slip length in various geometric pores (circular, square, equilateral triangle) are developed using the computational fluid dynamic (CFD) method. Through the quasi-static simulation technique, we estimate the flow properties in shale including capillary pressure and relative permeability. Simulation results confirm the slip effect would significantly affect oil-water two-phase flow in shale. And then, influences of shale pore structure on two-phase flow are further investigated. Through coupling network construction and two-phase flow simulation, we believe our work could shed light on the further research for multi-phase transportation in shale.

Sulfurized Polyacrylonitrile (S-PAN) has garnered extensive attention as cathode materials for Li S batteries in recent years because of its advantages such as high sulfur utilization efficiency, high Coulombic efficiency and low self-discharge rate. However, it is difficult to effectively balance the conflict between a high S loading (> 45 wt%) and cycling stability for S-PAN. In this work, we employed an in situ wrapping method to improve the cycling performance of high-S-content S-PAN. Compared with the unwrapped S-PAN, the capacity retention ratio of the wrapped S-PAN cathode increased from 38% to 62% after 100 cycles at 0.25C. The analyzed results suggested that the wrapping layer on the high-S-content S-PAN may compose a mixture of sulfide, inorganic LiBxOy and some organic compounds.

A novel integrated on-chip wavelength-based beam emitter is proposed and fabricated to realize two-dimensional optical scanning. By combining both wavelength division filters and emission array, 80 × 8 far-field optical beam spots are achieved with a field of view of 6° × 4°. Both collimation and projection modes are tested and 64 wavelength channels are realized in 10 nm bandwidth from 1550 to 1560 nm. This device can be used for LIDAR, optical wireless communication, and high-speed infrared imaging applications.

B3LYP/6-311++G(d,p) level of theory was carried out to explain the isomerization process of retinal stereoisomer based on the structural and molecular properties in gas phase and implicit aqueous environment. Frequency calculations on the fully optimized molecular geometries of the retinal isomers confirmed them to be true minima. The relative energies, dipole moments, bond orders, theoretically predicted vibrational frequencies, and HOMO–LUMO energy gaps of the retinal isomers were analyzed. The influence of the explicit aqueous environment on the geometrical parameters associated with the geometry of polyene chain and the vibrational spectra of retinal isomers were evident. The geometries of 11-cis and all-trans retinal isomers exhibited delocalized bonds along the polyene chain in the aqueous phase with a pattern of longer double bonds and shorter single bonds. The vibrational frequencies of the retinal isomers calculated at the B3LYP level of theory were in better agreement with the experimental values in the gas phase. The method and results presented in this study may help to better understand the effects of environment on its isomerization process.

Photostructurable Li2O-Al2O3-SiO2 glass is a promising material to fabricate complex three-dimensional structure with a high aspect ratio. However, its high dielectric loss at high frequencies has restrained its application in the field of integrated circuits packaging. In this research, La2O3, which has a large ionic radius, as well as strong polarization and bonding strength, was used to obstruct mobile ion migration to reduce the dielectric loss. The results indicated that moderate doping with La2O3 could effectively reduce the dielectric loss. When the dopant amount was 3%, the dielectric loss was successfully reduced to a minimum of 4 × 10−3 with a dielectric constant of 6.6 at 1 GHz, and this sample also possessed the optimal dielectric-temperature stability. Additionally, the effects of doping on the photosensitivity and crystallization behavior were also analysed. The results suggested that La2O3 doping did not affect the photosensitivity and selective crystallization characteristics. However, La2O3 restrained the precipitation of silicate from the [SiO4] tetrahedron, resulting in a decrease of nucleation rate and a delay of crystallization.

The catalytic conversion of nitrogen to ammonia is one of the most important processes in nature and chemical industry. However, the traditional Haber-Bosch process of ammonia synthesis consumes substantial energy and emits a large amount of carbon dioxide. Solar-driven nitrogen fixation holds great promise for the reduction of energy consumption and environmental pollution. On the basis of both experimental results and density functional theory calculations, here we report that the oxygen vacancy engineering on ultrathin BiOBr nanosheets can greatly enhance the performance for photocatalytic nitrogen fixation. Through the addition of polymetric surfactant (polyvinylpyrrolidone, PVP) in the synthesis process, VO-BiOBr nanosheets with desirable oxygen vacancies and dominant exposed {001} facets were successfully prepared, which effectively promote the adsorption of inert nitrogen molecules at ambient condition and facilitate the separation of photoexcited electrons and holes. The oxygen defects narrow the ...

Halobenzoquinones (HBQs) were reported as disinfection byproducts (DBPs) which had potential risk of bladder cancer. In this paper, a highly selective analytical method for HBQs was developed by HBQs-mediated assembly of amino acid modified Mn-doped ZnS/Quantum Dots (Mn: ZnS QDs). In the presence HBQs, a charge-transfer complex (CTC) was formed between aromatic rings of HBQs and the primary amino groups on the surface of the QDs. The formation of CTC led to the aggregation of QDs, as a result fluorescence decreasing occurred. The decrease was correlated with the concentration of HBQs. Then a fluorescence sensor array for discrimination of three kinds of HBQs including 2,6-Dichloro-1,4-benzoquinone (DCBQ), 2,6-Dibromo-1,4-benzoquinone (DBBQ) and 2,3,6-trichloro-1,4-benzoquinone (TCBQ) was developed. Four kinds of amino acids including cysteine, threonine, tyrosine and tryptophan were embellished on the Mn: ZnS QDs. The different extents of aggregation led to different fluorescence decreasing effect, thus distinct fluorescence patterns were created. It showed that three kinds of HBQs could be discriminated successfully by fluorescence sensor array at a range of concentrations through principal component analysis (PCA). The unknown samples were predicted by with a stepwise linear discriminant analysis (SLDA) using Mahalanobis distance as a selection criterion with accuracy of 100%. Remarkably, the practicability of the proposed sensor array was further validated by identification of three kinds of HBQs at different concentrations in real drinking water samples. Compared to LC/MS/MS, this fluorescent sensor array-based method was proved to be more convenient since the nanoparticles can be prepared flexibly according to the property of the target.

Obesity-induced colonic inflammation-stimulated colitis is one of the main causes of colorectal cancer. Dietary phytochemicals are considered to be an effective strategy for relieving obesity-induced inflammatory diseases such as diabetes and colitis. Ginsenoside Rk3 (Rk3) is the main bioactive component of ginseng. Our previous study has demonstrated that Rk3 can effectively alleviate obesity-induced type 2 diabetes, but whether it plays a beneficial role in obesity-induced colitis remains poorly understood. Here, we found that Rk3 intervention repaired the intestinal barrier dysfunction by increasing the expression of the tight junction proteins (zonula occludens-1, claudin, and occludin), and reduced colonic inflammatory cytokine levels, oxidative stress, and macrophage infiltration in high-fat diet-induced mice. Importantly, Rk3 effectively ameliorated the metabolic dysbiosis of intestinal flora with significantly decreased Firmicute/Bacteroidete ratios and suppressed the inflammatory cascade by inhibiting the TLR4/NF-κB signaling pathway. Taken together, our findings indicate that Rk3 can be used as a potential natural anti-inflammatory agent to reduce chronic obesity-induced colitis.

Xingfang Yu,1,* Xin Liao,2,* Hongwei Chen1 1Department of Orthopedics, The Affiliated Yiwu Hospital of Wenzhou Medical University, Yiwu, Zhejiang, 322000, People’s Republic of China; 2Department of Orthopedics, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325000, People’s Republic of China*These authors contributed equally to this workCorrespondence: Hongwei ChenDepartment of Orthopedics, The Affiliated Yiwu Hospital of Wenzhou Medical University, Yiwu, Zhejiang, 322000, People’s Republic of ChinaTel +86-13506896988Email sssaaa18@163.comBackground: Bone infections remain one of the most common and serious complications of orthopedic surgery, posing a tremendous economic burden to society and patients. This is because bacteria colonize and multiply on the surface of the implant. The (MMT/PLL)8 multilayer films have been shown to effectively release antibiotics depending on the changes in the microenvironment. Here, vancomycin was loaded into the (MMT/PLL)8 multilayer films, which were prepared to be used as a local delivery system for the treatment of bone infections.Methods: We used the layer-by-layer self-assembly method to prepare VA-loaded coatings (MMT/PLL-VA)8 consisting of montmorillonite (MMT), poly-L-lysine (PLL), and VA. The thickness and surface morphology of coatings were characterized using spectroscopic ellipsometry and scanning electron microscopy (SEM). In order to evaluate the drug release behavior from coatings in different media, we measured the size of the zone of inhibition. Additionally, in vitro antibacterial activity was assessed using the shake-flask culture method and SEM images, while that of in vivo was evaluated by establishing an animal model of bone infection.Results: Our findings revealed that small-molecule antibiotics were successfully loaded into the (MMT/PLL-VA)8 multilayer film structure during the hierarchical self-assembly process and subsequently the multilayer film structure depicted linear growth behavior. The PLL in the multilayer films was progressively degraded which triggered the VA release when contacted with CMS or bacterial infections. The release of VA from multilayer film structure depends on the concentration changes of CMS. Notably, the multilayer films presented great in vitro cell compatibility. Moreover, the prepared antibacterial multilayer films showed excellent antibacterial property by killing more than 99.99% of S. aureus in 24 h. More importantly, we found that multilayer film exhibits good sterilization effect and biocompatibility under the stimulation of bacterial liquid both in vitro and in vivo antibacterial ability tests.Conclusion: Altogether, this study shows that (MMT/PLL-VA)8 multilayer films containing CMS and bacteria-responsive drug release properties posess high bactericidal activity and good biocompatibility. This finding provides a novel strategy for the treatment of bone infections.Keywords: bone infections, multilayer films, microenvironment, layer-by-layer, antibacterial

The clathrin-associated protein adaptin-2 (AP2) is a distinctive member of the hetero-tetrameric clathrin adaptor complex family. It plays a crucial role in many intracellular vesicle transport pathways. The hydroxyapatite (HAp) nanoparticles can enter cells through clathrin-dependent endocytosis, induce apoptosis, and ultimately inhibit tumor metastasis. Exploring the micro process of the binding of AP2 and HAp is of great significance for understanding the molecular mechanism of HAp’s anti-cancer ability. In this work, we used molecular modeling to study the binding of spherical, rod-shaped, and needle-shaped HAps toward AP2 protein at the atomic level and found that different nanoparticles’ morphology can determine their binding specificity through electrostatic interactions. Our results show that globular HAp significantly changes AP2 protein conformation, while needle-shaped HAP has more substantial binding energy with AP2. Therefore, this work offers a microscopic picture for cargo recognition in clathrin-mediated endocytosis, clarifies the design principles and possible mechanisms of high-efficiency nano-biomaterials, and provides a basis for their potential anti-tumor therapeutic effects.

This paper is concerned with the monostability and bistability problem of probabilistic Boolean networks (PBNs). First, the concepts of the cycle and fixed point for the PBNs are put forward. Second, the definitions of (strictly) monostability and (strictly) bistability are introduced for the PBNs. Subsequently, a sufficient and necessary condition is derived for the monostability and bistability of the PBNs. In the light of the obtained sufficient and necessary condition, we consider the state feedback stabilization problem of probabilistic Boolean control networks (PBCNs). Specifically, we propose a method to determine whether the PBCN is (strictly) monostable or (strictly) bistable. Moreover, the state feedback controller has been designed for the state feedback stabilization of PBCNs. Finally, two examples, including the apoptosis network model, are given to illustrate the effectiveness of the obtained theoretical results.

Current circulating tumor cells (CTC) detection methods have to compromise between sensitivity and throughput. High-throughput imaging cytometer based on serial time-encoded amplified microscopy (STEAM) facilitates CTC detection at single-cell sensitivity from abundant cells. However, this method lacks the information to spot heterogeneity of cells with high morphological similarity. Researches on cell biophysical properties suggest cell mechanotyping can be an indicator of phenotypic heterogeneity to improve classification ability of STEAM cytometer. Here, we present a high-throughput label-free acoustofluidic imaging cytometer for single-cell mechanotyping based on STEAM and acoustofluidic technology. The generated acoustic resonance field translocates cells to different transversal exit positions under continuous flow according to their intrinsic biophysical properties. Such displacements are recorded with images simultaneously using STEAM cytometry at approximately 2000 cells/s. We experimentally verified that our method accounting for both cell images and acoustic displacements can improve mechanotyping accuracy by 12% upon image-based phenotyping method. This new acoustofluidic imaging cytometer facilitates high-accuracy and high-throughput imaging cytometry for single-cell CTC mechanotyping.

A comprehensive study was conducted to investigate the pyrolysis characteristics of municipal sludge, and the activation energy of sludge pyrolysis was determined using the Model-free method. The detailed migration characteristics of heavy metals in the pyrolysis products were also investigated at different pyrolysis temperatures (250–850 °C). The results demonstrate that sludge pyrolysis is a multi-step process; the activation energy of pyrolysis increased with the pyrolysis conversion rate, and the average activation energy was calculated as 79.59 kJ mol−1. As the pyrolysis temperature increased, the char yield decreased, the tar yield increased then decreased, and the gas yield increased. At 850 °C, the thermal volatilities of heavy metals followed the sequence Cu

The aim of the study was to investigate the protective effects of selenium yeast (SeY) against necroptosis triggered by Cd via inhibition of oxidative stress and MAPK pathway in the liver of chicken. Two hundred 120-day-old layers were randomly divided into four groups and raised for 120 days. The histopathological examination showed that necrosis characteristics were observed in Cd-exposed chicken livers. The exposure of Cd significantly reduced the activities of SOD, GSH-Px and CAT while improving MDA level in both serum and liver of chickens (P 0.05), and induced oxidative stress. The MLKL, Rip1, RIP3, ERK, JNK and P38 mRNA expression of Cd group were significantly higher than other three groups (P ＜ 0.01), and those in the Se + Cd group were significantly higher than control group and Se group (P ＜ 0.01). However, the mRNA expression level of caspase8 of Cd was significantly lower than other three groups (P ＜ 0.01), and that in the Se + Cd group was significantly higher than control group and Se group (P ＜ 0.01), so the supplement of SeY could improve these situations. Similar results were also detected at the protein level. The results of the present study indicated that Cd could induce oxidative stress, activate MAPK pathway and evoke necroptosis damage in chicken livers, whereas SeY had protective effects in preventing this kind of Cd-induced injury by inhibition of oxidative stress and down-regulation MAPK pathway.

Rice undergoes leaf senescence accompanied with grain filling when the plants reach the end of their temporal niche, and a delay in leaf senescence ultimately improves the yield and quality of grain. To estimate the decline in photosynthesis during leaf senescence and to find an efficient and useful tool to identify rice genotypes with a longer duration of active photosynthesis, we examined PSII photosynthetic activity in the flag leaves of japonica rice Shennong265 (SN265) and Beigeng3 (BG3) during leaf senescence using chlorophyll a fluorescence kinetics. The results show that inhibition occurred in the electron transport chains, but the energetic connectivity of PSII units was not affected as dramatically during leaf senescence. PSII reaction centres (RCs) were transformed into ‘silent RCs,’ and the chlorophyll content decreased during leaf senescence. However the size of the ‘economic’ antennae increased. Further, the percentage of variation of the specific energy flux parameters can rationally be used to indicate leaf senescence from the perspective of energy balance. Although the performance indices were more sensitive than other functional and structural JIP-test parameters, they still did not serve as an indicator of crop yield.