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The Early Paleozoic eclogite belt extends discontinuously for ~500 km within the East Kunlun Orogen (EKO) and records the subduction history of the Proto-Tethys Ocean. This eclogite belt, therefore, is an excellent site for studying the first-order transition in convergent-margin tectonic systems, and the tectonic events associated with subduction and collision can be determined by reconstructing the high-pressure (HP)–ultrahigh-pressure (UHP) P–T–time path. In this contribution, we present P–T results from phase equilibrium modeling and Zr-in-rutile/titanite thermometry for eclogites located on the east and west sides of the EKO. In the eastern EKO, MT–UHP eclogite records peak conditions of ~30 kbar/650–720 °C, retrograde conditions of 10 kbar at ~650–700 °C, and then further retrograde conditions at 3–6 kbar and 500–580 °C. In the western EKO, LT–HP eclogite records peak conditions of ~27 kbar at 570 °C and then retrograde conditions at 10 ± 2 kbar/470–560 °C. These two types of eclogite record oceanic subduction (west) and continental collision (east), respectively. The EKO, therefore, contains two types of eclogites that indicate two end-member subduction complexes within the orogenic belt, further indicating that there are differences in the subduction-depth and collision-time from east to west. This finding is consistent with asymmetric suturing of the subducted Proto-Tethys Ocean within the EKO. Together, the P–T conditions and time-scales of the HP–UHP metamorphism can be applied to understand the process from subduction to collision between the Qaidam Block and the South Kunlun Block, as a consequence of asymmetric closure of the Proto-Tethys Ocean.

International audience; High-quality microwave amplifiers and notch-filters can be made from microwave optomechanical systems in which a mechanical resonator is coupled to a microwave cavity by radiation pressure. These amplifiers and filters rely on optomechanically induced transparency (OMIT) and absorption (OMIA), respectively. Such devices can amplify microwave signals with large, controllable gain, high dynamic range and very low noise. Furthermore, extremely narrowband filters can be constructed with this technique. We briefly review previous measurements of microwave OMIT and OMIA before reporting our own measurements of these phenomena, which cover a larger parameter space than has been explored in previous works. In particular, we vary probe frequency, pump frequency, pumping scheme (red or blue), probe power, pump power and temperature. We find excellent agreement between our measurements and the predictions of input/output theory, thereby guiding further development of microwave devices based on nanomechanics.

The effective detecting ONOO− variations in vivo is of great importance to well understand the complex pathophysiological processes. We reported here a photoacoustic (PA) probe AZB-1 for imaging ONOO− in vivo. AZB-1 showed an originally strong photoacoustic signal at 660 nm. And its PA signal can be turned off by shutting the ICT effect caused by the conjugated electron withdrawing group at 2-position of the aza-BODIPY core. Moreover, the probe was successfully employed to imaging ONOO− variations in inflammatory mice models. Wisely utilized this strategy may serve as powerful platforms for the preparation of novel PA chemosensors.

The rapid recombination of photogenerated charges is one of the main restriction for promoting the photocatalytic H2 generation of graphitic carbon nitride (CN) material. Herein, donor-acceptor (D-A) system was introduced into CN nanosheets by oxygen and/or phenyl doping (DA-CN) strategy to facilitate the transport of photoinduced charge carriers and H2 generation. Experimental and theoretical results revealed that the nanosheet structure of DA-CN shortened the photoexcited charges transport length to the surface, and the D-A system embedded in DA-CN provided the dipole-induced internal electric field for charges transport. As a consequence, compared with pristine CN, DA-CN samples performed the improved transport of photogenerated charges and photocatalytic H2 evolution. Notably, DA-CN-OP (oxygen and phenyl co-doping) with the strongest dipole-induced internal electric field originated from D-A system displayed the highest photocatalytic H2 evolution rate at 7.394 mmol g−1h−1, which was 7.67 times as that of pristine CN (0.964 mmol g−1h−1). This work not only provides a simple strategy to construct highly efficient CN nanosheet photocatalyst with D-A system, but also promote the deep insight into the effect of molecular dipole originated from D-A system on the transport of photoinduced charge carriers and photocatalytic activity for CN material.

Big data is transforming our world, revolutionizing operations and analytics everywhere, from financial engineering to biomedical sciences. The complexity of big data often makes dimension reduction techniques necessary before conducting statistical inference. Principal component analysis, commonly referred to as PCA, has become an essential tool for multivariate data analysis and unsupervised dimension reduction, the goal of which is to find a lower dimensional subspace that captures most of the variation in the dataset. This article provides an overview of methodological and theoretical developments of PCA over the last decade, with focus on its applications to big data analytics. We first review the mathematical formulation of PCA and its theoretical development from the view point of perturbation analysis. We then briefly discuss the relationship between PCA and factor analysis as well as its applications to large covariance estimation and multiple testing. PCA also finds important applications in many modern machine learning problems, and we focus on community detection, ranking, mixture model and manifold learning in this paper., review article, in press with Wiley StatsRef

Grain boundaries (GBs) relaxation is a promising and effective strategy to improving GB stability or stabilizing nanocrystalline metals. However, previous studies mainly focused on nanocrystalline pure metals and GB behaviors therein, without considering the role of foreign atoms such as impurity or alloying atoms in GB relaxation. In this work, the shear-strain induced structural relaxation of pure Cu Σ3 [110](112) symmetric tilt GBs (STGBs), and the effects of foreign elements (Fe and Ni) and temperature on the GB relaxation were investigated in detail by molecular dynamics method. The results show that shear strain can trigger the structural relaxation of pure, Fe- and Ni-containing Cu GBs by the emission of Shockley partial dislocations from Cu GBs. Both Fe and Ni have impediment effects on the shear-strain induced GB relaxation, though the content of Fe or Ni atom (0.00165 at.%) is quite low in the GB model. The temperature cannot trigger GB relaxation independently within the considered temperature range, but play a positive role in the shear-strain induced structural relaxations of pure, Fe- and Ni-containing Cu Σ3 [110](112) STGBs. Our work might gain new insights into the mechanically induced GB relaxation in nanocrystalline copper and could be beneficial for improving the stability of Cu GBs.

Polygoni Multiflori Radix Praeparata (PMRP) is used as Chinese herbal medicine with long history. However, reports about PMRP hepatotoxicity have increased recently, and producing area might be one reason. This article aims to figure out the relationship between producing area and hepatotoxic ingredients in PMRP. HPLC fingerprint for PMRP was established and the contents of gallic acid, trans-stilbene glycoside (TSG), emodin-8-O-β-D-glucoside (EG), emodin and physcion were determined. Clustering heatmap was implemented by TCMNPAS software，and principal component analysis was implemented by SPSS and SIMCA-P software. Hepatotoxic constituents’ contents of PMRP from separate producing area were different. PMRP from Guangxi had the highest content of gallic acid, TSG, EG, emodin and physcion, followed by Hubei, Guangdong, Guizhou, Yunnan. PMRP from Henan had the lowest contents of hepatotoxic components. Hepatotoxic components’ contents of PMRP in southern were higher than central China. This study carried out a preliminary qualitative and quantitative investigation on the PMRP from different producing places, which provided a basis for safe medication of PMRP.

This paper gives a solution of Problem 1.8 in [16] . As a corollary, it is shown that every connected non-bipartite Cayley graph on a solvable group of valency at least three is at most 2-arc-transitive.

Despite the critical role of subduction in plate tectonics, the dynamics of its initiation remains unclear. High-temperature low-pressure metamorphic soles are vestiges of subduction initiation, providing records of the pressure and temperature conditions along the subducting slab surface during subduction initiation that can possibly differentiate the two end-member subduction initiation modes: spontaneous and induced. Here, using numerical models, we show that the slab surface temperature reaches 800–900 °C at ~1 GPa over a wide range of parameter values for spontaneous subduction initiation whereas for induced subduction initiation, such conditions can be reached only if the age of the overriding plate is, The mechanism of subduction initiation is a key to modern plate tectonics. Here, using numerical modeling and geological observations, the authors find that the majority of active and paleo subduction zones with metamorphic soles likely formed during induced subduction initiation that involved a young overriding plate.

Hierarchical porous iron and nitrogen co-doped carbon (Fe-N/C) materials have been considered as an appealing non-noble metal-based catalyst in oxygen reduction reactions (ORR). However, the conductivity loss caused by the scattering of electrons on pores and defects markedly limits their catalytic activity, which attracted seldom attention in this area. Herein, a novel crystalline carbon modified hierarchical porous Fe-N/C electrocatalyst with enhanced electronic conductivity is designed and prepared via a two-step calcination-catalysis process. The resistivity of hierarchical porous Fe-N/C is decreased from 2.123 Ω cm to 0.479 Ω cm after crystalline carbon introduction. The electrocatalyst annealed at 800 °C (Fe-N/C-800) exhibits a superior activity with the half-wave potential (E1/2) of 0.89 V, which outperforms the commercial carbon-supported platinum (Pt/C) catalyst (0.85 V). The strategy of crystalline carbon modification provides a fresh approach to improve the electronic conductivity of porous carbon-based materials.

A three-dimensional heterogeneous bubble nucleation model is constructed to provide a reasonable explanation at the molecular level for the foaming mechanism of polypropylene (PP) and polystyrene (PS) blends. CO2 solubilities and supersaturation rations are quantitatively calculated to help interpret the contribution of each phase of the blend in the CO2 dissolution stage. The spatial density profiles of polymer/CO2 binary melt around different polymer chains are presented to give an intuitive perspective to the thermodynamic driving force. The predicted interfacial tension and contact angles of critical bubbles provide valid evidence to distinguish the wettability of CO2 in different regions. The values of predicted free-energy barriers, critical radii, and nucleation number densities imply that bubbles that nucleate in the PP and PS blend interfacial region attached to the PS-rich phase achieve the smallest size and largest number density. The reliability of the theoretical model has been tested by partial available experimental data.

Constructing highly active and stable surface sites for O2 activation is essential to lower the barrier of Pt-based catalysts for CO oxidation. Although a few active Pt-metal oxide interfaces have been reported, questions about the stability of these sites under the long-term storage and operation remain unresolved. Here, based on developing a robust FeOx/LaFeO3 heterostructure as a support, we constructed stable Pt-support interfaces to achieve highly active CO oxidation at room temperature. Even after it is kept in the air for more than 6 months, the catalyst (without pretreatment) still maintains the high activity like a fresh one, which is superior to metal hydroxide-Pt interfaces, and meets the requirements of long-term storage for emergency use. In situ characterizations and systematic reaction results showed that CO oxidation occurs through an alternative mechanism, which is triggered by intrinsic reactants and self-adjusted to a more active interface in the reaction process. Theoretical calculations and 57Fe Mossbauer spectra revealed that abundant cation vacancies significantly increase the activity of surface oxygen species and should be responsible for this unique process. This work demonstrates an alternative concept to fabricate robust and highly active Pt-based catalysts for catalytic oxidation.

Hierarchical TS-1 has attracted enormous attention from both academia and industry due to its remarkable catalytic performance in epoxidation reactions. However, sustainable synthesis of hierarchical-nanosized TS-1 without mesoporogens is still challenging. In this work, we report a facile and mesoporogen-free strategy to simultaneously manipulate pore structure and particle size of TS-1 employing the concentrated system. Taking advantage of the suspended nuclei in the concentrated system as confirmed by the DLS-PSD and atomic force microscopy, the novel TS-1 is demonstrated to have higher Ti concentration on surface, higher surface area (539 m2/g), abundant mesopores, and reduced crystal size (ca. 150 nm). Moreover, this Au-Ti bifunctional catalyst shows a good PO formation rate with enhanced catalytic stability due to the hierarchical structure. This strategy opens a novel way for the green synthesis of hierarchical-nanosized TS-1 and facilitates industrial development of the Au/TS-1 catalyst for propene epoxidation.

The rational fabrication of heterostructures is one of efficient strategies for improving photocatalytic performance of semiconductor photocatalysts. Very recently, Domen and co-workers found that Ta3N5 single crystals grown on the surface of KTaO3 can accomplish photocatalytic overall water splitting for the first time. In order to comprehend the underlying mechanism of this photocatalytic system, we have performed a systematic study based on density functional theory first-principles calculations. Ta3N5(010)/KTaO3(110) slab models have been built according to experimental observations by considering two common terminations of KTaO3(110) surface, named as Ta3N5/O2 and Ta3N5/KTaO. The formations of interfacial bonds are thermodynamically stable, showing a covalent interaction between two components of a heterostructure. Ta3N5/O2 has a higher mobility of photogenerated charge carriers and lower recombination rate of charge carriers than Ta3N5/KTaO. The light absorption of heterostructures displays the feature of KTaO3 in the short wavelength region and the characteristic of Ta3N5 in the long wavelength region. The calculated band offsets show that Ta3N5/O2 and Ta3N5/KTaO have distinct Type-II band alignments, with Ta3N5 as the accumulator of photoinduced electrons in the former and the collector of photogenerated holes in the latter, respectively. The difference in charge density and electrostatic potential between two components acts as a driving force to promote the transfer of electrons and holes to different domains of the interface, which is beneficial to extend the lifetime of photoinduced carriers. Our results demonstrate that the function of Ta3N5 in Ta3N5/KTaO3 photocatalytic system is determined by the termination property of KTaO3(110) surface, which provides a likely reason of the observed photocatalytic activity of overall water splitting achieved by Ta3N5 synthesized by using KTaO3 as a precursor for the nitridation reaction.

Considerable efforts are being invested to explore alternative ceramic materials to yttria stabilized zirconia (YSZ) for thermal barrier coating (TBC) applications. In this work, 18 mol% YO1.5 stabilized HfO2 (18YSH) is proposed as potential TBC material. Stoichiometric 18YSH was prepared by atmospheric plasma spraying. The 18YSH coating exhibits low thermal conductivity over the whole temperature range investigated and a minimum thermal conductivity of 0.832 W/m·K at 800 °C. Average hardness and Young's modulus values have been determined to be 7.01 ± 1.33 GPa and 111 ± 26.8 GPa respectively. These values are superior to those exhibited by YSZ coating. In addition, the sintering temperature of 18YSH coating is at least 100 °C higher than that of a 8 YSZ coating and thus 18YSH will be more resistant to sintering. Finally, 1) the coating reliability of 18YSH TBC has been studied by thermal cycling to 1100 °C and 2) calcium–magnesium–alumino-silicate-(CMAS)-induced degradation was investigated at 1250/1300 °C. The related failure mechanism was investigated and a model describing the CMAS degradation process is presented.

Due to the intensive human activities and rapid economic development during the past few decades, the anthropogenic sourced nitrogen (N) input into coastal waters has increased dramatically. In this study, the net anthropogenic nitrogen input (NANI), including the deposition of atmospheric N, the application of N fertiliser, the fixation of biological N, and the net N inputs from food and feed, into the Zhanjiang Bay watershed from 1978 to 2018 were estimated using statistical data, and the driving forces were analysed using the Logarithmic Mean Divisia Index (LMDI) factor decomposition approach. The results show that the NANI dramatically increased from 5269 to 20 639 kg N km−2. The cause of this increase was related to high input from N fertilisers and the net food and feed N input (with average contributions of 56.45% and 41.42%, respectively), which was accompanied by rapid economic development in Zhanjiang Bay. The output from the LMDI illustrates that the cause of the changes in the NANI was a shift in the dietary structure instead of an increase in the human population, which suggests that the impact of human population on the increase in the NANI using simple relational analysis may be overestimated. Remarkably, we found that the N from aquatic protein and animal protein comprised a significant proportion of the total N consumption in this coastal city, which differs from previous studies of inland cities. This is likely due to the fact that aquaculture is significantly developed in this coastal city.

This paper presents an experimental study of the fundamental phenomena of progressive creeping discharge as well as the influences of pressboard ageing and voltage amplitude under divergent AC voltages. A ramp-stress test is used to determine the partial discharge inception voltage (PDIV) and the flashover voltage of oil/pressboard interface versus pressboard ageing. Constant-stress tests are carried out to investigate the partial discharge (PD) behaviors, the pressboard surface temperature, and the oil-dissolved gases of progressive creeping discharges. It is found that the pressboard ageing affects only the interface PDIV. The progressive creeping discharges concentrate at the triple-junction and comprises probably oil corona discharges and surface discharges in pressboard dimples. If no pressboard damage is present, the progressive discharges exhibit in general a constant PD pattern but a diminishing intensity, and nevertheless can be sustained for the severely-aged pressboards under strong voltages. The underlying causes are correlated with the competing effects of pressboard ageing on interface moisture and the triple-junction field intensification. Gas analyses indicate the hydrogen is the principal faulty gas and the Duval's Triangle diagnoses the progressive creeping discharges as either low-energy or high-energy discharge fault. No pressboard overheating is observed during the discharges.

This paper presents both an experimental study and a theoretical discussion on the relevant faults resulting from progressive creeping discharge. Pressboard ageing, voltage amplitude, and pressboard type are configured to generate the faults under divergent creeping stresses. The fault progression is recorded by high-resolution camera, partial discharge (PD) device, and optic-fiber thermometer. The damaged pressboards are scrutinized by microscopy and image-processing techniques, and gas chromatography is used to analyze the gas compositions. The progression of internal treeing shows distinct stages of different interface phenomena, such as spark discharge, white marks, and bubbling effect, as well as varying discharge patterns. In contrast, the progression of surface tracking is a simple but hardly noticeable process due to the PD disappearance. The internal carbonization channels are believed the fundamental causes of the interface phenomena pertinent to internal treeing. A theoretical model is proposed to expound the development of the internal carbonization channels, which considers the charge emission, the pressboard pyrolysis, and the percolation theory. The failure mode of internal treeing is schematically illustrated using a four-phase model, and the effects of thermal ageing and field distribution on surface tracking are discussed. Lastly, a detailed comparison is made between internal treeing and surface tracking in terms of the occurrence condition, initiation mechanism, growth driver, and growth characteristics.

In this letter, we propose a lightweight yet effective Topology Guided Kinodynamic planner (TGK-Planner) for quadrotor aggressive flights with limited onboard computing resources. The proposed system follows the traditional hierarchical planning workflow, with novel designs to improve the robustness and efficiency in both the pathfinding and trajectory optimization sub-modules. Firstly, we propose the topology guided graph , which roughly captures the topological structure of the environment and guides the state sampling of a sampling-based kinodynamic planner. In this way, we significantly improve the efficiency of finding a safe and dynamically feasible trajectory. Then, we refine the smoothness and continuity of the trajectory in an optimization framework, which incorporates the homotopy constraint to guarantee the safety of the trajectory. The optimization program is formulated as a sequence of quadratic programmings (QPs) and can be iteratively solved in a few milliseconds. Finally, the proposed system is integrated into a fully autonomous quadrotor and validated in various simulated and real-world scenarios. Benchmark comparisons show that our method outperforms state-of-the-art methods with regard to efficiency and trajectory quality. Moreover, we will release our code as an open-source package. 1 1 Code is released at https://github.com/ZJU-FAST-Lab/TGK-Planner .

6-Formylisoophiopogonone B (7a) and 8-formylophiopogonone B (7b), two natural products isolated from Ophiopogon japonicus, represent a subgroup of rare 6/8-formyl/methyl-homoisoflavonoid skeletons. Herein we report an efficient method for the synthesis of these formyl/methyl-homoisoflavonoids. The synthesized compounds were evaluated for their neuroprotective effects on the MPP+-induced SH-SY5Y cell injury model and showed marked activity. Exploration of the neuroprotective mechanisms of compound 7b led to an increased expression of autophagy marker LC3-II and down-regulation of autophagy substrate p62/SQSTM1. Molecular docking studies showed that 7b may prevent the inhibition of the classic PI3K-AKT-mTOR signaling pathway by interfering with the human HSP90AA1.

High performance Microelectromechanical system (MEMS) gyroscopes are in great demand in the fields of precise navigation, automatic driving and precise attitude measurement. Honeycomb disk resonator gyroscope(HDRG) which works on wineglass-modes has many advantages including higher immunity to fabrication errors, better resonant mode consistency and better inner electrode arrangement, showing excellent potentials to be the next-generation MEMS gyroscope with high performance and good robustness. In this paper, a new HDRG prototype is designed based on the comprehensive optimizations of resonant structure and electrode configuration. The main structure parameters and the lumped-mass configuration are optimized systematically through the finite element simulation, while the configuration and arrangement of the inner electrodes are optimized based on the vibration amplification effect, offering systematic reference for the optimizations of other MEMS gyroscopes. The new HDRG is fabricated through a SOI fabrication technique and tested with a close-loop digital circuit. Quality factor of the optimized HDRG prototype reaches 650k, proving to be a record in silicon disk resonator gyroscopes. The bias instability of the optimized gyroscope reaches 0.015°/h under room temperature without any compensation, approaching the accuracy of navigation grade. Scale factor nonlinearity reached around 120ppm in the range of ±300°/s without compensation. The comprehensive performance is at the forefront of MEMS resonant gyroscopes.

Accurate roof segmentation is one of the key steps for automatically constructing three-dimensional (3-D) building models. Building roofs can differ significantly in terms of their size, shape comp...

Endogenous salicylic acid (SA) regulates leaf senescence, but the underlying mechanism remains largely unexplored. The exogenous application of SA to living plants is not efficient for inducing leaf senescence. By taking advantage of probenazole (PBZ)-induced biosynthesis of endogenous SA, we previously established a chemical inducible leaf senescence system that depends on SA biosynthesis and its core signaling receptor NPR1 in Arabidopsis thaliana. Here, using this system, we identified WRKY46 and WRKY6 as key components of the transcriptional machinery downstream of NPR1 signaling. Upon PBZ treatment, the wrky46 mutant exhibited significantly delayed leaf senescence. We demonstrate that NPR1 is essential for PBZ/SA-induced WRKY46 activation, whereas WRKY46 in turn enhances NPR1 expression. WRKY46 interacts with NPR1 in the nucleus, binding to the W-box of the WRKY6 promoter to induce its expression in response to SA signaling. Dysfunction of WRKY6 abolished PBZ-induced leaf senescence, while overexpression of WRKY6 was sufficient to accelerate leaf senescence even under normal growth conditions, suggesting that WRKY6 may serve as an integration node of multiple leaf senescence signaling pathways. Taken together, these findings reveal that the NPR1-WRKY46-WRKY6 signaling cascade plays a critical role in PBZ/SA-mediated leaf senescence in Arabidopsis.

The hot corrosion behavior of YSZ/ZrW2O8 composites as a promising thermal barrier coating system exposed to V2O5 at 700 °C and 850 °C was investigated in order to better understand the influence of the incorporated ZrW2O8 with isotropic negative thermal expansion performance on the corrosion resistance. Results indicate that the ZrW2O8 incorporation could retard the degradation of YSZ from V2O5 attack and the corrosion process is significantly related to the inclusion content and the temperature. The corrosion resistance could be determined by the incorporation content, while the reaction products are only temperature dependent. At 700 °C, ZrV2O7, YVO4 and m-ZrO2 were the main corrosion products, while ZrW2O8 recrystallized under the acidic environment provided by V2O5. At 850 °C, ZrW2O8 decomposed and only WO3, YVO4 and m-ZrO2 could be detected as final corrosion products. The corrosion mechanisms of YSZ/ZrW2O8 composites at 700 °C and 850 °C were discussed based on the phase diagrams and Lewis acid-base rule as well as the volume compensation of the positive and negative expansion ceramics.

We start up the study of the stability of general graph pairs. This notion is a generalization of the concept of the stability of graphs. We say that a pair of graphs ( Γ , Σ ) is stable if Aut ( Γ × Σ ) ≅ Aut ( Γ ) × Aut ( Σ ) and unstable otherwise, where Γ × Σ is the direct product of Γ and Σ. An unstable graph pair ( Γ , Σ ) is said to be a nontrivially unstable graph pair if Γ and Σ are connected coprime graphs, at least one of them is non-bipartite, and each of them has the property that different vertices have distinct neighborhoods. We obtain necessary conditions for a pair of graphs to be stable. We also give a characterization of a pair of graphs ( Γ , Σ ) to be nontrivially unstable in the case when both graphs are connected and regular with coprime valencies and Σ is vertex-transitive. This characterization is given in terms of the Σ-automorphisms of Γ, which are a new concept introduced in this paper as a generalization of both automorphisms and two-fold automorphisms of a graph.

Ce and Mn modified TiO2 sorbents (CeMnTi) were prepared by a co-precipitation method, and their ability to remove elemental mercury from coal gas in a fixed bed reactor was studied. Based on results of Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS) studies, the modification mechanisms of the CeMnTi sorbents are discussed. Mn doping improved the specific surface area and dispersion of cerium oxides on the sorbent surface, while Ce doping increased the proportion of Mn4+ in manganese oxides by a synergetic effect between manganese oxides and cerium oxides. The effects of the active component, temperature, and coal gas components on the mercury removal performance of the sorbents were investigated. The results showed that the CeMnTi sorbents exhibited high mercury removal efficiency. Ce0.2Mn0.1Ti adsorbed 91.55% elemental mercury from coal gas at 160 °C. H2S and O2 significantly improved the ability of sorbents to remove mercury. Part of the H2S formed stable sulfates or sulfites through a series of oxidation reaction chains on the sorbent surface. HCl also improved the mercury removal performance, but reduced the promotion effect of H2S for mercury removal when coexisting with H2S. CO and H2 had a minor inhibitory effect on mercury adsorption. The recycling performance of the sorbents was investigated by thermal regeneration. The thermal decomposition of the used sorbents indicated that mercury compounds were present mainly in the form of HgO and HgS, and higher temperature was beneficial for regeneration. The formation of sulfates and sulfites in the presence of H2S led to a decrease in mercury removal efficiency.

Herein, we disclose a ruthenium-catalyzed meta-selective C-H activation of phosphines by using intrinsic P(III) as a directing group. 2,2,6,6-Tetramethylheptane-3,5-dione acts as the ligand and exhibits an excellent performance in boosting the meta-alkylation. The protocol allows an efficient and straightforward synthesis of meta-alkylated tertiary phosphines. Several meta-alkylated phosphines were evaluated for Pd-catalyzed Suzuki coupling and found to be superior to commercially available ortho-substituted phosphines. The practicability of this methodology is further demonstrated by the synthesis of difunctionalized phosphines.

The thermal performance of building walls could be improved by using phase change material (PCM), and there is already a lot of research about the heat transfer characteristics of PCM walls. However, the moisture transfer characteristics of PCM walls have rarely been studied. It is known that the heat transfer and the moisture transfer in the walls are highly coupled, and the moisture transfer process will also be affected when the wall is integrated with PCM. Therefore, a coupled heat and moisture transfer model for the walls with PCM was developed in this paper. The model was firstly validated by the experimental results, and then, it was used to investigate the characteristics of the moisture transfer in the PCM walls. Two series simulations, with different boundary conditions, were conducted. The results showed that the PCM not only had effects on the heat transfer in the wall, but also had effects on the moisture transfer in the wall. Compared with the wall without PCM, the peak relative humidity and the peak moisture flux of the wall with PCM were both small. Compared with the relative humidity fluctuation range of the wall without PCM, it was 77.03% lower when the wall contained 50% PCM. Compared with the moisture flux fluctuation range of the wall without PCM, it was 63.61% lower when the wall contained 50% PCM. The condensation risk in the wall could be reduced by using PCM.

Coastal reclamation projects have been extensively constructed along the coastline of the East China Sea over the past decades. To investigate the impact of reclamations on the Rui’an coastal zone, regional tidal and sediment dynamics were studied by combining field data and numerical modeling. Field data of tidal elevation and currents, suspended sediment concentration (SSC), and bottom erosion were obtained during both spring and neap tides from 2014 to 2019. Data analysis suggested that the reclamation and construction of the dike reduced the currents in the tidal flat and subsequently reduced the SSC values. The sediment was mainly deposited in the tidal flat after construction. The largest annual deposition rate was approximately 1 m, occurring in the southern part near the dike, while the deposition rate was only 0.08 m/a in the middle part of the tidal flat. In addition, the results of the numerical experiment proved that the reclamation and dike construction contributed to the variations in currents and SSC, thus altering the deposition in the tidal flat. It is suggested that the construction of coastal works and social facilities in macro-turbid coastal zones, such as the Rui’an coast, require the evaluation of possible impact on sediment dynamics.

Background Pretreatment is the key step for utilizing lignocellulosic biomass, which can extract cellulose from lignin and disrupt its recalcitrant crystalline structure to allow much more effective enzymatic hydrolysis; and organic acids pretreatment with dual benefic for generating xylooligosaccharides and boosting enzymatic hydrolysis has been widely used in adding values to lignocellulose materials. In this work, furoic acid, a novel recyclable organic acid as catalyst, was employed to pretreat sugarcane bagasse to recover the xylooligosaccharides fraction from hemicellulose and boost the subsequent cellulose saccharification. Results The FA-assisted hydrolysis of sugarcane bagasse using 3% furoic acid at 170 °C for 15 min resulted in the highest xylooligosaccharides yield of 45.6%; subsequently, 83.1 g/L of glucose was harvested by a fed-batch operation with a solid loading of 15%. Overall, a total of 120 g of xylooligosaccharides and 335 g glucose could be collected from 1000 g sugarcane bagasse starting from the furoic acid pretreatment. Furthermore, furoic acid can be easily recovered by cooling crystallization. Conclusion This work put forward a novel furoic acid pretreatment method to convert sugarcane bagasse into xylooligosaccharides and glucose, which provides a strategy that the sugar and nutraceutical industries can be used to reduce the production cost. The developed process showed that the yields of xylooligosaccharides and byproducts were controllable by shortening the reaction time; meanwhile, the recyclability of furoic acid also can potentially reduce the pretreatment cost and potentially replace the traditional mineral acids pretreatment.

As one of the most important imaging modalities, magnetic resonance imaging (MRI) still faces relatively low sensitivity to monitor low-abundance molecules. A newly developed technology, hyperpolarized 129Xe magnetic resonance imaging (MRI), can boost the signal sensitivity to over 10 000-fold compared with that under conventional MRI conditions, and this technique is referred to as ultrasensitive MRI. However, there are few methods to visualize complex mixtures in this field due to the difficulty in achieving favorable “cages” to capture the signal source, namely, 129Xe atoms. Here, we proposed metal–organic frameworks (MOFs) as tunable nanoporous hosts to provide suitable cavities for xenon. Due to the widely dispersed spectroscopic signals, 129Xe in different MOFs was easily visualized by assigning each chemical shift to a specific color. The results illustrated that the pore size determined the exchange rate, and the geometric structure and elemental composition influenced the local charge experienced by xenon. We confirmed that a complex mixture was first differentiated by specific colors in ultrasensitive MRI. The introduction of MOFs helps to overcome long-standing obstacles in ultrasensitive, multiplexed MRI., Metal organic frameworks with tunable pore structures are able to provide varied chemical environments for hyperpolarized 129Xe atom hosting, which results in distinguishing magnetic resonance signals, and stains ultra-sensitive magnetic resonance imaging (MRI) with diverse colors.

Multifilamentary Bi2Sr2CaCu2Ox (Bi2212) composite wires are the only high-temperature superconducting round wires (RWs) with sufficient critical current density (Jc) for superconducting magnets generating magnetic fields greater than 25 T. Previous works indicated that various voids in Bi2212 filaments and bridges between the adjacent Bi2212 filaments in Bi2212 RWs were generated after heat treatment. Such complicated microstructural structure will inevitably affect its electrical behavior. Previous studies only focus on single microstructural feature, voids or bridges. Hence, we developed a numerical model containing both voids and bridges to explore the comprehensive influence of these two microstructural features. Due to the preliminary results, it shows that the E-J relationships of the models with bridges and with infinity bridges are similar in the case of numerous bridges between filaments. It indicated that we can build a simplified geometry structural model by removing all the bridges and bonding the adjacent filaments directly. And then the parametric study of the voids was carried out and the results explained that the height (diameter) of void is the key factor to dominant its electrical behavior.

Flexoelectricity and photoelectricity with their coupled effect (the so-called flexo-photoelectronic effect), are of increasing interest in the study of electronics and optoelectronics in van der Waals layered semiconductors. However, the related device design is severely restricted owing to the ambiguous underlying physical nature of flexo-photoelectronic effects originating from the co-manipulation of light and strain-gradients. Here, flexoelectric polarization and the flexo-photoelectronic effect of few-layered semiconductors have been multi-dimensionally investigated from high-resolution microscopic characterization on the nanoscale, physics analysis, and deriving a device design. We found that two back-to-back built-in electric fields form in bent InSe and WSe2, and greatly modulate the transport behaviors of photogenerated carriers, further facilitating the separation of photogenerated electron–hole pairs and trapping the holes/electrons in InSe or WSe2 channels, recorded in realtime by a home-made technique of lighting Kelvin probe force microscopy (KPFM). The slow release of trapped carriers contributes to the photoconductance relaxation after illumination. Utilizing the photoconductance relaxation, a light-stimulated artificial synapse based on the flexo-photoelectronic effect of bent InSe has been achieved. Significantly, all the pair-pulse facilitation (PPF) behavior, spike frequency-dependent excitatory post-synaptic current (EPSC) and the transition from short-term memory (STM) to long-term memory (LTM) have been successfully realized in this artificial synapse. This work adds to the investigation of flexo-photoelectronic effects on 2D optoelectronics, and moves towards the development of 2D neuromorphic electronics.

This paper considers the problems of finite-time prescribed performance tracking control for a class of strict-feedback nonlinear systems with input dead-zone and saturation simultaneously. The unknown nonlinear functions are approximated by fuzzy logic systems and the unmeasurable states are estimated by designing a fuzzy state observer. In addition, a non-affine smooth function is used to approximate the non-smooth input dead-zone and saturated nonlinearity, and it is varied to the affine form via the mean value theorem. An adaptive fuzzy output feedback controller is developed by backstepping control method and Nussbaum gain method. It guarantees that the tracking error falls within a pre-set boundary at finite time and all the signals of the closed-loop system are bounded. The simulation results illustrate the feasibility of the design scheme.

Production of glyceric acid (GLA) by the oxidation of glycerol is a promising green and efficient process, which could replace conventional biological fermentation with low efficiency. However, simultaneously achieving the efficient oxidation of glycerol to GLA and the separation of subsequent products remains a challenging task due to the easy decomposition and condensation of selective oxidation products at high temperature. Herein, we propose a novel glycerol to GLA process (termed as VDG process) by bringing insight into the essence of thermal-sensitivity. In the VDG process, glycerol is selectively oxidized to GLA and other thermal-sensitivity byproducts by our recently developed PtRu/MCM-41 nanocatalysts under base-free conditions. The high purity separation of products is realized at a temperature lower than its decomposition temperature through integrating the vacuum dividing wall columns. This intensified process reduces the energy consumption and production cost. Compared with the conventional glycerol to GLA process, this VDG process provided up to 61.3% increase in energy efficiency and 47.9% reduction of the total production costs. Moreover, the life cycle assessment from multi-scales obviously indicates that the performance of greenhouse gas emissions, non-renewable energy demand and waste water generation in the VDG process are about 5.0 times, 1.6 times and 9.5 times lower than the conventional process, respectively. The results in this study harbour tremendous guiding significance to the design of efficient biomass polyol conversion to value-added products.

A novel composite consisting of NiO/NiC/g-C3N4 with excellent photocatalytic properties was successfully synthesized by the simple calcination of layered double metal hydroxide (LDH) and melamine. The color and chemical composition of the as-prepared composites could be tailored by changing the mass ratio of NiAl-LDH and g-C3N4. For the L4C composite at the ratio of 1 : 1, it showed the desired dark color due to the generated NiC. It also showed high photodegradation efficiency under visible light irradiation, reaching 97.5% toward Rhodamine B and 92.6% toward tetracycline. The high photodegradation efficiency could be mainly attributed to the unique formation of NiC cocatalysts coupled with g-C3N4 and NiO semiconductors, which constructed a Z-scheme system and facilitated the efficient separation of the photogenerated electron–hole pairs. The present findings provide a promising approach for fabricating the new types of composite photocatalysts for pollutant degradation.

Battery-type electrode materials show inferior power density due to sluggish ion-diffusion kinetics within the solid phase. Herein, we outline a strategy to improve the cation migration for ultrafast energy storage by utilizing a built-in electric field (BEF) at the heterostructure interface. Both theoretical calculations and Kelvin probe measurements reveal that two kinds of BEF – in opposite directions – are produced at fully charged and discharged states on co-axial MoOx/MoON nanotubes (NTs). The transport kinetics are greatly increased by the BEF effect, leading to a dramatic increase of capacitance, especially at a high charging rate. Subsequently, MoOx/MoON NTs exhibit a specific capacitance of 1976 F cm−3 at a current density of 2.5 A cm−3. And 1267 F cm−3 is retained at a high current density of 100 A cm−3, which can be ascribed to the improvement of fast ionic transport in the electrode bulk caused by the BEF effect. This work also inspires a new pathway toward rational engineering of heterostructures for high-capacitance and high-rate energy storage.

As a versatile quantification and tracking technology, 19F magnetic resonance imaging (19F MRI) provides quantitative “hot-spot” images without ionizing radiation, tissue depth limit, and background interference. However, the lack of suitable imaging agents severely hampers its clinical application. First, because the 19F signals are solely originated from imaging agents, the relatively low sensitivity of MRI technology requires high local 19F concentrations to generate images, which are often beyond the reach of many 19F MRI agents. Second, the peculiar physicochemical properties of many fluorinated compounds usually lead to low 19F signal intensity, tedious formulation, severe organ retention, etc. Therefore, the development of 19F MRI agents with high sensitivity and with suitable physicochemical and biological properties is of great importance. To this end, perfluoro-tert-butanol (PFTB), containing nine equivalent 19F and a modifiable hydroxyl group, has outperformed most perfluorocarbons as a valuable building block for high performance 19F MRI agents. Herein, we summarize the development and application of PFTB-based 19F MRI agents and analyze the strategies to improve their sensitivity and physicochemical and biological properties. In the context of PFC-based 19F MRI agents, we also discuss the challenges and prospects of PFTB-based 19F MRI agents.

Vanadium dioxide has been widely investigated as a thermochromic smart window material. However, it has mediocre thermochromic properties (low solar modulation ability ΔTsol, low luminous transmission Tlum and high transition temperature (τc)). More importantly, the Achilles heel of VO2 is its thermodynamically unstable characteristics which severely hinder its commercialization. Different approaches have been investigated to enhance its thermochromic properties and nanocomposites outperformed other methods according to calculations and experiments. The conventional nanocomposite technique is to disperse VO2 nanoparticles (NPs), usually made by the solution process, into a transparent media and the highest ΔTsol could only reach 20% theoretically. In this report, we employed the glass industry compatible process of magnetron sputtering, followed by rapid thermal annealing (RTA). Instead of the usual continuous films, this thin film process gave a unique structure where VO2 NPs are dispersed in a V2O5/V3O7 matrix with a dense thermodynamically stable V2O5 overcoat. This new type of nanocomposite gives a nearly doubled ΔTsol (20%) compared with that of the best reported continuous single vanadium oxide film (10%). The accelerated test suggested that the expected service life of this film is 23 years, which is a breakthrough in VO2 based thermochromic smart windows. The high durability, due to the encapsulation of V2O5, together with the significantly enhanced thermochromic properties and facile industry compatible process, provide a new strategy to scale up this technology into real-world applications.

Codoping with cations and anions is found to be an effective approach to tailor the electronic structures of semiconductor-based photocatalysts. In this work, a systematic hybrid density functional study has been carried out for BaTiO3 with a wide bandgap, codoped with TM and X (TM = V, Nb, Ta, Mo and W, X = N and C), with the objective of improving its photocatalytic activity for water splitting under visible light irradiation. Oxygen-rich conditions are found to be more favorable for the synthesis of the (TM + X)-codoped materials, and under these conditions, the formation energy for the codoped BaTiO3 is even lower than that of the TM-monodoped system. A smaller deformation of the BaTiO3 crystal structure corresponds to a more favorable formation of (TM + X)-codoped systems. Passivated codoping is found to be advantageous because it effectively reduces the band gap without encountering any localized impurity states observed in the related monodoped systems. The band alignments for all the codoped systems are well positioned for the feasibility of both photooxidation and photoreduction of water. It is found that there are seven investigated systems with bandgaps smaller than 3 eV. Among them, passivated codoped systems including Mo and W have been found to be the most effective for narrowing the bandgap (Eg is in the range of 1.55–2.16 eV), increasing the mobilities of photoinduced carriers and improving the photocatalytic activity of BaTiO3 under visible light. These materials are promising photocatalysts for overall water splitting under visible-light irradiation and further experimental investigations are highly demanded to explore their potential applications in the photocatalytic field.

Supercapacitors are highly attractive in the large-scale energy storage field, but the “trade-off” between the gravimetric capacitance and the volume and area specific capacitance greatly affects their further development. In this work, we developed coralloid-like porous carbon sheets (CPCS) with double support structure via a bidirectional anchoring strategy, exhibiting ultra-low specific surface area (26.95 m2 g−1) and moderate packing density (0.75 g cm−3). In the meantime, the proposed dual-anchor structure model made the interior “self-doping” defects and the exterior “foreign-doping” defects fully exposed, which is seldom obtained by other artificial methods. Based on this, it delivered a superior overall performance in gravimetric, volumetric, and areal capacitances (308.89 F g−1, 231.67 F cm−3, and 1146 μF cm−2) and stable cyclability (10 000 cycles), which is the highest capacitance reported for polyacrylonitrile-based hard carbon without chemical/physical activation. Considering the low-energy and innovative synthesis route, our work may shed some light on developing advanced carbons promising for supercapacitors.

Cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) are essential biothiols for cellular growth, metabolism, and maintenance of a biological system. Thus, the detection of biothiols is highly important for early diagnosis and evaluation of disease progression. In this article, a series of sulfonyl aza-BODIPYs was synthesized, characterized, and examined by 1H-NMR, 13C-NMR, crystallization, photophysical properties and DFT calculation. Among these structures, a fluorescent probe, BDP-1, exhibited selective detection of Cys among various biothiols via nucleophilic aromatic substitution and typical size of Cys molecules. BDP-1 showed color change and near-infrared (NIR) fluorescence enhancement after reaction with Cys to generate BDP-OH, confirmed by HRMS. The red shift of absorption wavelength showed a similar tendency resulting in time-dependent density functional theory (TD-DFT). Furthermore, the calculated detection limit of BDP-1 toward Cys was 5.23 μM. This probe facilitates the colorimetric and fluorescent detection of Cys over other biothiols.

Surface passivation with organic materials is one of the most effective and popular strategies to improve the stability and efficiency of perovskite solar cells (PSCs). However, the secondary bonding formed between organic molecules and perovskite layers is still not strong enough to protect the perovskite absorber from degradation initialized by oxygen and water attacking at defects. Recently, passivation with inorganic materials has gradually been favored by researchers due to the effectiveness of chemical and mechanical passivation. Lead-containing substances, alkali metal halides, transition elements, oxides, hydrophobic substances, etc. have already been applied to the surface and interfacial passivation of PSCs. These inorganic substances mainly manipulate the nucleation and crystallization process of perovskite absorbers by chemically passivating defects along grain boundaries and surface or forming a mechanically protective layer simultaneously to prevent the penetration of moisture and oxygen, thereby improving the stability and efficiency of the PSCs. Herein, we mainly summarize inorganic passivating materials and their individual passivation principles and methods. Finally, this review offers a personal perspective for future research trends in the development of passivation strategies through inorganic materials.

Background Vaccination provides a viable alternative to antibiotics for the treatment of drug-resistant bacterial infection. Bacterial protoplasts have gained much attention for a new generation vaccine due to depleting toxic outer wall components. Purpose The objective of this study was to reveal the effects of bacterial protoplast-derived nanovesicles (PDNVs) size on antibacterial immunity. Methods Herein, we prepared bacterial PDNVs with different sizes by removing the cell wall of Staphylococcus aureus (S. aureus) to generate multi-antigen nanovaccines. Furthermore, we investigated the ability of PDNVs in different sizes to activate dendritic cells (DCs) and trigger humoral and cellular immune responses in vivo. Results We obtained particles of ∼200 nm, 400 nm, and 700 nm diameters and found that all the PDNVs readily induce efficient maturation of DCs in the draining lymph nodes of the vaccinated mice. Dramatically, the activation of DCs was increased with decreasing particle sizes. In addition, vaccination with PDNVs generated elevated expression levels of specific antibody and the production of INF-γ, especially the smaller ones, indicating the capability of inducing strong humoral immunity and Th1 biased cell responses against the source bacteria. Conclusion These observed results provide evidence for size-dependent orchestration of immune responses of PDNVs and help to rationally design and develop effective antibacterial vaccines.

Our exploration of multimodal nanoprobes aims to combine photoacoustic (PA) imaging, 19F magnetic resonance (MR), and fluorescence (FL) imaging, which offers complementary advantages such as high spatial resolution, unlimited penetration, and high sensitivity to enable more refined images for accurate tumor diagnoses. In this research, perfluorocarbons (PFCs) and indocyanine green (ICG) are encapsulated by poly(lactic-co-glycolic acid) (PLGA) for intravital 19F MR/FL/PA tri-modal imaging-guided photothermal therapy. Then, it is coated with an A549 cancer cell membrane (AM) to fabricate versatile theranostic nanoprobes (AM-PP@ICGNPs). After systemic administration, FLI reveals time-dependent tumor homing of NPs with high sensitivity, 19F MRI provides tumor localization of NPs without background signal interference, and PAI illustrates the detailed distribution of NPs inside the tumor with high spatial resolution. What is more, AM-PP@ICGNPs accumulated in the tumor area exhibit a prominent photothermal effect (48.4 °C) under near infrared (NIR) laser irradiation and realize an enhanced antitumor response in vivo. These benefits, in combination with the excellent biocompatibility, make AM-PP@ICGNPs a potential theranostic nanoagent for accurate tumor localization and ultimately achieve superior cancer therapy.

Four polysaccharides, MFPA1, MFPA2, MFPB1, and MFPB2, were isolated from Mori Fructus using DEAE-52 cellulose chromatography. MFPA1 (177 kDa) was composed of mannose, rhamnose, glucose, and xylose,...

Here, we reported a strategy for channel methylation to construct a robust ultramicroporous metal-organic framework (MOF) Ni(TMBDC)(DABCO)0.5 through hydrothermal synthesis method and investigated its adsorption performance for recovering ethane (C2) and propane (C3) from natural gas. The as-synthesized Ni(TMBDC)(DABCO)0.5 featured ultramicroporosity with a uniform pore size of 0.5 nm. The resulting sample showed a strong adsorption interaction with C3H8 and C2H6, and its C3H8 adsorption capacity at a low pressure of 1 kPa was up to 2.80 mmol/g and its C2H6 adsorption capacity at a low pressure of 10 kPa reached as high as 2.93 mmol/g, exhibiting strong binding affinity for ethane and propane. The enhanced adsorption can be attributed to the presence of the dense and accessible methyl and methylene groups in the channels of the sample. Grand Canonical Monte Carlo (GCMC) simulations also confirmed that the methylene groups from the DABCO pillar and the methyl groups from the TMBDC ligand play an important role in enhancing the adsorption of ethane and propane. Its ideal adsorbed solution theory (IAST)-predicted selectivity of C2H6/CH4 reached unprecedentedly 29, much higher than most of the reported data for MOFs. The stability test confirmed that the crystal structure of Ni(TMBDC)(DABCO)0.5 still remained intact after it was exposed to moist air with a relative humidity of 100% for days. The breakthrough experiment demonstrated that the CH4/C2H6/C3H8 ternary mixture was completely separated using a fixed bed of Ni(TMBDC)(DABCO)0.5 at ambient temperature, showing a great potential for recovering the low content of ethane and propane from natural gas.

Primary dendritic arm spacing (PDAS) is an important microstructure feature of the nickel-base single crystal superalloys. In this paper, a numerical model predicting the PDAS evolution with additive manufacturing parameters using pulsed laser is established, which combines the theoretical PDAS models with the temperature field calculation model during pulsed laser process. Based on this model, processing maps that related process parameters to the evolution of PDAS are generated. To obtain more accurate prediction model, the parameters of different solidification conditions, $$\overline{{G^{ - 0.5} V^{ - 0.25} }}$$ and $$\overline{{G}^{-0.5}{V}^{-0.25}}$$ , are selected to calculate PDAS. The simulation results show that the PDAS increases as the arise of P and t. The processing-PDAS map can accurately predict the evolution of PDAS with pulsed laser process parameters, which is well in accordance with the experimental results. Additionally, the PDAS values calculated by the $$\overline{{G}^{-0.5}{V}^{-0.25}}$$ are more in line with the experimental results than those calculated by the $${\bar{G}}^{-0.5}{\bar{V}}^{-0.25}$$ .

A multi-scale peridynamic (PD) model of concrete with three material phases is developed to study the influences of the properties of the interfacial transition zone (ITZ) on chloride diffusion. In the PD model, the quadtree algorithm is employed to generate the multi-scale grid and two correction schemes based on the background grid are developed to calibrate the volume and length of PD bonds. A comparison with the uniform grid PD model and the finite element model is carried out to validate the proposed multi-scale PD model. The results of the multi-scale PD model are consistent with that of the two models. In addition, the effects of ITZ properties, including ITZ diffusivity and ITZ thickness, on chloride diffusion are investigated. These results demonstrate that the penetration depth and the chloride concentration increase with the increasing ITZ diffusivity and ITZ thickness, and the increase rate of chloride concentration decreases with the exposed time.

Background Phylogenetic relationships among the myriapod subgroups Chilopoda, Diplopoda, Symphyla and Pauropoda are still not robustly resolved. The first phylogenomic study covering all subgroups resolved phylogenetic relationships congruently to morphological evidence but is in conflict with most previously published phylogenetic trees based on diverse molecular data. Outgroup choice and long-branch attraction effects were stated as possible explanations for these incongruencies. In this study, we addressed these issues by extending the myriapod and outgroup taxon sampling using transcriptome data. Results We generated new transcriptome data of 42 panarthropod species, including all four myriapod subgroups and additional outgroup taxa. Our taxon sampling was complemented by published transcriptome and genome data resulting in a supermatrix covering 59 species. We compiled two data sets, the first with a full coverage of genes per species (292 single-copy protein-coding genes), the second with a less stringent coverage (988 genes). We inferred phylogenetic relationships among myriapods using different data types, tree inference, and quartet computation approaches. Our results unambiguously support monophyletic Mandibulata and Myriapoda. Our analyses clearly showed that there is strong signal for a single unrooted topology, but a sensitivity of the position of the internal root on the choice of outgroups. However, we observe strong evidence for a clade Pauropoda+Symphyla, as well as for a clade Chilopoda+Diplopoda. Conclusions Our best quartet topology is incongruent with current morphological phylogenies which were supported in another phylogenomic study. AU tests and quartet mapping reject the quartet topology congruent to trees inferred with morphological characters. Moreover, quartet mapping shows that confounding signal present in the data set is sufficient to explain the weak signal for the quartet topology derived from morphological characters. Although outgroup choice affects results, our study could narrow possible trees to derivatives of a single quartet topology. For highly disputed relationships, we propose to apply a series of tests (AU and quartet mapping), since results of such tests allow to narrow down possible relationships and to rule out confounding signal.