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To confirm the robustness of a tunnel, the quality of the rock mass is usually evaluated by several rock mass classification (RMC) systems before its design. Besides, the accuracy of the RMC should be checked through the correlations between different RMC systems. The relationship between the different RMC systems and P-wave velocity indexes is conducive to the interpretation of the rock mass. Here, based on linear or nonlinear regression analysis of 231 samples, we established the RMR–Q, [BQ]–Q, and [BQ]–RMR relationships with R2 = 0.935, 0.732, and 0.759, respectively. Further analysis showed that the grading differences between any two RMC systems yield different characteristics when the rock mass score is at different intervals. To evaluate the relations between RMC indexes and P-wave velocity, we conducted a group study on the different grading differences among RMR, Q, or BQ. Depending on the consistency of the grading results, we arranged the values from large to small as the amplitude of the slope of the curve, and the grading results differed by either one or two levels. Our data demonstrated that the grading differences between the systems are proportional to the discontinuous state of rock mass in the classification. In addition, the classification results of Q, RMR, and BQ showed more significant differences when less consideration is given to the integrity of the rock mass.

A case of Qinghuayuan tunnel excavation below the existing Beijing Subway Line 10 is presented. The new Qinghuayuan tunnel, part of the Beijing-Zhangjiakou High-speed Railway, was excavated by a shield machine with an outer diameter of 12.2 m. The existing subway was excavated by shallow tunnelling method. The project layout, geological conditions, reinforcement measures, operational parameters of shield machine and monitoring results of the project are introduced. During the Qinghuayuan tunnel excavation below the existing subway, total thrust, shield driving speed, cutterhead rotation speed and torque were manually controlled below the average values obtained from the previous monitoring of this project, which could effectively reduce the disturbance of the surrounding soil induced by shield excavation. The Gaussian fitting function can appropriately fit both the ground and the existing subway settlements. The trough width is influenced not only by the excavation overburden depth, but also by the forepoling reinforcement and tail void grouting measures.

To study the mechanical responses of large cross-section tunnel reinforced by pretensioned rock bolts and anchor cables, an analytical model is proposed. Considering the interaction between rock mass and bolt-cable support, the strain softening characteristic of rock mass, the elastic-plastic characteristic of bolt-cable support, and the delay effect of installation are considered in the model. To solve the different mechanical cases of tunneling reinforced by bolt-cable support, an analytical approach has been put forward to get the solutions of stress and displacement associated with tunneling. The proposed analytical model is verified by numerical simulation. Moreover, parametric analysis is performed to study the effects of pretension force, cross-section area, length, and supporting density of bolt-cable support on tunnel reinforcement, which can provide references for determining these parameters in tunnel design. Based on the analytical model, a new Ground Response Curve (GRC) considering the reinforcement of bolt-cable support is obtained, which shows the pretension forces and the timely installation are important in bolt-cable support. In addition, the proposed model is applied to the analysis of the Great Wall Station Tunnel, a high-speed railway tunnel with a super large cross-section, which shows that the analytical model of bolt-cable support was a useful tool for preliminary design of large cross-section tunnel.

Based on the elastohydrodynamic theory, the nonlinear dynamic behavior of worn oil-lubricated rolling bearings is explored, and the dynamic response including the effect of trajectory of the axis center, the accelerated speed, and the film thickness is analyzed. The worn model is represented by the worn depth. The discrete iterative method and implicit Euler method are combined to solve the dynamic equations. In numerical examples, the trajectory of the axis center, the accelerated speed and the film thickness under different worn depths are discussed. It is found that the stabilized point shows significant variation with the worn depth, and the wear effect is also quite related with the rolling speed. The trajectory of the axis center of worn bearing subjected to a step load is also examined in detail.

The fast recombination of photogenerated electrons and holes in the pure TiO2 leads to a low photocatalytic efficiency in hydrogen generation or solar energy conversion. Noble metal nanoparticles have been used to combine with TiO2 for effective photocatalysis. Herein, Au@Ag@TiO2 nanorods (NRs) with core–shell structure have been prepared by hydrolysis the precursor of titanium in acid environment. UV light–driven H2 generation rate of Au@Ag@TiO2 samples demonstrated 14 times enhancement compared to P25 TiO2 at the same experimental conditions. The improved photocatalytic performance was due to the charge transfer from the conduction band of excited TiO2 to Au@Ag NRs leading to effective separation of electron–hole pairs. This mechanism has been proved by transient absorption spectroscopy and photo-electrochemical (PEC) measurements. The time resolved photocurrents of P25 TiO2 NPs is ~ 13 times higher that of Au@Ag@TiO2, indicating that a fraction of the photogenerated electrons of TiO2 driven by UV light transfer to Au@Ag nanocores instead of transporting entirely to the ITO substrates. The ultrafast transient absorption and pump-probe measurements demonstrated a faster decay in Au@Ag@TiO2 NRs compared to pure TiO2 system, indicating that the photogenerated electron–hole recombination in TiO2 is substantially suppressed by Au@Ag@TiO2 NRs attributed to the effective trapping of the photogenerated electrons by the Au@Ag cores. Au@Ag@TiO2 nanocomposites with core-shell structure have been prepared and its UV light–driven H2 generation rate has been demonstrated 14 times enhancement compared to P25 TiO2 at the same experimental conditions. The improved photocatalytic performance was due to the charge transfer, which has been proved by photocurrent measurement and the ultrafast transient absorption and pump-probe measurements.

A coumarinocoumarin-based fluorescent probe, JCCA, was developed for the detection of N2H4. JCCA exhibited a fast turn-on fluorescence enhancement in response to N2H4 with good selectivity, sensitivity and a detection limit of 7.4 nmol/L. Significantly, JCCA displayed a good capability for visualizing N2H4 in living cells and zebra fish.

With increasing age, plants will cause changes in soil physicochemical properties. The objective of this study was to investigate differences in the soil physicochemical properties in different-aged Masson pine forest plantations (i.e., 10, 20, 40, and 60 years old). Soil samples were collected in a pure Masson pine forest plantation in Southwest China. The soil determination indexes included organic carbon, nitrogen, phosphorus and potassium contents, water content, bulk density, and pH. The soil pH of a 20-year-old forest was significantly (p &lt, 0.05) higher than that of a 10, 40, and 60-year-old forest. In addition, soil-available phosphorus in a 60-year-old forest was significantly (p &lt, 0.05) higher than that in the other three age forest groups. With increasing forest age, available phosphorus increased, while available nitrogen decreased at 20 years old and then increased at 40 years old. There was a significant positive correlation (p &lt, 0.05) between total nitrogen and available potassium, no significant correlation (p&gt, 0.05) between total phosphorus and total potassium, organic carbon, bulk density, and pH, and a significant negative correlation (p &lt, 0.05) between available phosphorus and the water content. The availability and utilization efficiency of soil nutrients in young forests were higher than those in old forests and the intermediate forest age was an important time point that affected the soil properties. To improve the availability of soil nutrients and ensure the sustainable utilization of soil resources, it is necessary to increase the input of nitrogen and especially phosphorus. More attention should be given to the phytochemometric response with respect to the age of plantations.

By combining Biot's dynamic wave theory with the elastic and slip interface theory, the scattering of plane waves around a saturated lining structure embedded in saturated soil is studied. The lining structure is assumed to be arbitrary shape. Separating variable method of Helmholtz equations leads to the semi-analytical solutions of the potentials. By using the conformal mapping method, the lining structures of arbitrary shape can be mapped to the cirque at the same centre with different radii. The elastic and slip material constants of interface are introduced to analyze the effect of interfacial properties. The dynamic stress and pore pressure are solved by applying the displacement and stress boundary conditions with interface effect. In numerical examples, the dynamic stress and pore pressure under different interface coefficients (normal and circumferential spring coefficients and slip coefficient) are analyzed. It is found that the effect of normal spring coefficient is larger than that of circumferential spring coefficients. The imperfect interface effect on the dynamic stress and pore pressure is also related with the wave frequencies.

Rapid and non-destructive detection of circulating tumor cells (CTCs) with no disruption of their functions is of great significance for clinical tumor therapy. However, many existing methods for CTC detection commonly rely on conventional three-color immunofluorescence identification, which damages CTCs and easily causes loss of cells. Here, we employed a method to simultaneously capture and authenticate CTCs based on immunonanocomposites (ZnS:Mn2+ QDs and Fe3O4/SiO2) equipped with permanent fluorescent and magnetic properties. A multifunctional nanocomposite was synthesized by encapsulating ZnS:Mn2+ quantum dots (QDs) and Fe3O4 nanoparticles into SiO2 nanospheres and bio-conjugating tumor-specific anti-EpCAM antibodies onto the surface. The resulting nanocomposite had a high tumor cell binding ability, and the Fe3O4 nanoparticles had a rapid magnetic response that enabled capture of circulating tumor cells from patients' blood within minutes. In addition, the cell-immunonanocomposites complexes could be directly recognized by the yellow-orange light emitted by the ZnS:Mn2+ quantum dots, thus labeling cells without utilizing the complicated and destructive procedures involved in traditional CTCs identification. We successfully achieved a high capture efficiency of up to 90.8%, and the specific fluorescence labeling of CTCs was realized in 9 clinical breast cancer patients' samples. Furthermore, this simple, convenient and cell-friendly approach is significant for solving the problems of cell viability and enables non-destructive CTC detection, which marks an advance in cancer treatment and clinical applications.

Nostoc was orally administered to mice to evaluate the possible effects on cyclophosphamide (CY)-induced immunosuppression. The results showed that feeding Nostoc may promote the growth of mice. Me...

The excavation of large-span triple tunnels using drilling and blasting method inevitably causes complicated load transfer effects and induces potentially damaging ground vibrations. In this study, the structural responses (including the surrounding rock pressure, normal-contact pressure between the primary and secondary linings, internal forces in the secondary lining) and the seismic responses (including peak particle velocity and corner frequency), are systematically recorded. It is found that the first-excavated left tunnel is influenced heavily by the excavation of the last-excavated middle tunnel, whereas it is hardly affected by the excavation of the second-excavated right tunnel. The load carried by the primary lining is approximately three times as that carried by the secondary lining. The middle tunnel was in the least desirable state due to the formation of the large Protodyakonov’s equilibrium arch (PEA). Based on timely feedback of the comprehensive monitoring system, a series of vibration-reducing techniques were applied and effectively guaranteed safety during blasting construction. By referring to Chinese codes, the minimum safety factor of the secondary lining is 1.3; the maximum PPV (0.15 cm/s) is lower than the allowable value; and the corner frequency (40-140 Hz) will not cause resonant vibration of the Great Wall.

Leaf litter is an important component of agroforestry ecosystems that plays a key role in soil and water conservation. This study assessed the effect of leaf shape on water interception under controlled laboratory conditions. Two contrasting leaf shapes (needle-leaf, represented by Pinus massoniana; and broad-leaf, represented by Magnolia grandiflora) were placed in a steel box (2 m long and 1 m wide) for separate experiments with different leaf masses per ground area (0.5, 1.0 and 1.5 kg/m2); the steel box was positioned on two different slopes (5° and 20°) corresponding to gentle and steep slopes; the rainfall intensity was 90 mm/h. The results indicated that leaf shapes had specific effects on the interception storage capacity of the leaf litter on a slope. The needle-leaf litter intercepted 2.08 times more rainwater than the broad-leaf litter on average. As the leaf mass increased, the interception storage capacity of the leaf litter successively increased for the needle-leaf litter, while there were no obvious patterns for the broad-leaf litter. This difference occurred because the initially erect broad leaves were easily flattened by raindrop impacts due to their large surface areas and hence formed a horizontal leaf cover (or leaf overlap). This leaf accumulation structure restricted the infiltration of rainwater into the lower leaf litter while providing a short path for rainwater to leave the leaf litter, hence promoting litter flow and leading to less rainwater intercepted by the broad-leaf litter than the needle-leaf litter. Our results provide a better understanding of the effects of leaf shape on leaf litter interception on inclined slopes, which is lacking in the current literature.

This paper illustrates the surface settlement characteristics of subway station construction in the shallow-buried soft ground using the pile-beam-arch (PBA) approach of the shallow tunnelling method. The geological conditions, cross sections and measured surface settlements of 30 subway stations constructed by the PBA approach in Beijing are presented. The total surface settlements of the strip foundation station and the pile foundation station using the PBA approach mainly range from 40 mm to 80 mm and from 30 mm to 40 mm, respectively. The superposition of the surface settlements in Stage 1 and 3 of the PBA approach accounts for about 90% of the total surface settlement, and that in Stage 2 and 4 accounts for about 10%. The mean of the surface settlements produced in silty clay is smaller than that in silty sand, and is approximately 1.4 times as large as that in gravel. The surface settlement generally decreases with the increase of the overburden depth. The surface settlement could more than double due to the effect of groundwater. The surface settlement induced by the excavation of the latter level of drifts is commonly larger than that of the former level of drifts. In addition, the quality of workmanship has significant impacts on the surface settlement. This research is conducive to update the database of the world subway projects and can serve as a practical reference for future similar projects.

Immunomagnetic micro/nanoparticles (IMNs) have been widely used to isolate rare circulating tumor cells (CTCs) from blood samples for early diagnosis of cancers. However, when entering into biofluids, IMNs nonspecifically adsorb biomolecules and the in situ formed biomolecule corona covers IMN surface ligands and weakens the targeting capabilities of IMNs. In this work, we demonstrated that by surface coating of IMNs with red blood cell (RBC)-derived vesicles, the obtained biomimetic particles (RBC-IMNs) basically adsorb no biomolecules and maintain the CTC targeting ability when exposed to plasma. Compared to IMNs, RBC-IMNs exhibited an excellent cell isolation efficiency in spiked blood samples, which was improved to 95.71% from 60.22%. Furthermore, by using RBC-IMNs, we successfully isolated CTCs in 28 out of 30 prostate cancer patient blood samples and further showed the robustness of RBC-IMNs in downstream cell sequencing. The work presented here provides a new insight into developing targeted nanomaterials for biological and medical applications.

Local topography and elevation gradients can exert important influences on soil formation processes such as elemental migration, mineral weathering, and soil organic matter (SOM) accumulation, yet these influences remain insufficiently investigated to date, particularly in surface soils of subtropical monsoonal regions. Here, we report on an investigation of a series of surface soils collected from four different topographic locations across the subalpine Dajiuhu Critical Zone Observatory (CZO), representing hillslope (planar), swale and river channel (convergent), and bulge (divergent) microtopographic sites. Evidence provided by rare-earth element (REE) patterns, immobile element ratios, clay-mineral compositions, and particle-size distributions suggests that these soils have rather uniform parent materials. X-ray diffraction (XRD) analysis revealed that secondary clay minerals in these soils are complex, being dominated by various interstratified clays. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy shows similar patterns among the swale, bulge, and river-channel soils that differ from those of the hillslope soils. Most soils at convergent sites with poor drainage contain more smectitic clays (interstratified illite/smectite and chlorite/smectite) and less vermiculitic clays (hydroxyl-interlayered vermiculite and interstratified illite/hydroxyl-interlayered vermiculite), and exhibit weaker chemical weathering and fewer elemental losses than those from non-convergent sites. The diversity of clay types can be ascribed to the complexity and heterogeneity, in particular of pH and hydrology, in these soil environments. Across the range of microtopographic sites investigated here, elemental migration and chemical weathering are generally coupled, with greater elemental losses associated with more intense chemical weathering. Soil organic carbon (SOC) content generally increases at higher elevations, which is attributable to lower temperatures and a consequent reduction of microbial remineralization, and under more reducing soil water conditions. Though influenced by eolian dust, variations in Fe/Mn, Ce anomaly, and Corg/P can reflect redox conditions of different soils. SOC retention is also closely associated with soil redox status, with more reducing conditions being more conducive to SOC preservation.

We introduce EdgeNet, a metric learning architecture for extracting semantic local shape features, directly applicable to a wide range of shape analysis applications such as point matching, object classification, shape segmentation, and partial registration. EdgeNet is based on a novel technique to keep edge-wise correspondences in the deep feature space and encodes the local structure into the learned features. It is trained under the supervision of edge-wise correspondences by using the 3D coordinates. The training loss combines a bi-triplet loss to enforce feature variations between the semantic matching points in the feature space, a transformation loss to encourage consistency between corresponding edges after alignment transformation, and a smoothness loss guarantees the flatness between the nearest points in the feature space. The learned features are proved to encode local content, structure, and asymmetry for 3D shapes. Our network can be adapted to either 3D meshes or point clouds. We compare the performance of the EdgeNet with existing state-of-the-art approaches and demonstrate the efficiency and efficacy of EdgeNet in three shape analysis tasks, including shape segmentation, partial matching, and shape retrieval.

Terrestrial Permian–Triassic boundary (PTB) sequences in South China usually contain one to three ash beds (K-bentonites), which provide evidence of a possible trigger for the terrestrial mass extinction and are useful as a distinct marker for correlation of the PTB boundary interval from terrestrial to marine areas. Here, we investigate the clay mineralogy and geochemistry of ash beds in the Zhejue and Jiucaichong sections, representing paludal and lacustrine environments, respectively, in order to better understand the source(s) and preservation of these ash beds. The two Zhejue K-bentonites exhibit similar compositions that are distinctly different from that of the Jiucaichong K-bentonite. The former contain mainly clay minerals with minor quartz, anatase, and lepidocrocite, and the clay minerals in these layers are mainly R1 and R3 mixed-layer illite/smectite (I/S) and well-crystallized to poorly-crystallized kaolinite, whereas the latter consists mainly of R3 I/S with minor quartz, feldspars, and anatase. The former have higher CIA values (92.2 and 93.8) than the latter (79.4), indicating more intense chemical weathering that may have been related to deposition in a paludal setting with high organic acid concentrations in pore fluids. These K-bentonites also exhibit differences in major-element chemistry (MgO and K2O contents are higher at Jiucaichong due to lesser weathering intensity and, possibly, early diagenetic uptake from pore fluids), REE chemistry (Jiucaichong exhibits a larger Eu anomaly), and Nd isotopic compositions (Zhejue K-bentonites have 143Nd/144Nd ratios of 0.512436 and 0.512400, higher than the 0.512190 ratio for Jiucaichong). Although some of these compositional differences may be related to the dissimilar chemical environments in which diagenesis occurred (i.e., paludal vs lacustrine), the differences in Eu anomalies and Nd isotopic compositions imply heterogeneous volcanic ash sources. The source of these K-bentonites was probably a continental volcanic arc located on the paleo-southern margin of the South China Craton, within which multiple volcanic vents may have been active concurrently.

Factors controlling variations in the clay mineralogy and geochemical composition of volcanic ash beds deposited in different types of depositional environments remain incompletely understood. The well-correlated, altered volcanic ash beds (tuffs or K-bentonites) of Permian-Triassic boundary (PTB) successions in South China provide an opportunity to better understand processes of alteration and diagenesis of volcanic materials in terrestrial, paralic, and marine sedimentary facies. The types of authigenic clay minerals produced vary among facies: mainly mixed-layer illite/smectite (I/S) clays in deep-marine, shallow-marine, and lacustrine facies, and kaolinite and mixed-layer I/S or kaolinite/smectite (K/S) clays in paludal and mixed marine-terrestrial facies. Furthermore, the stacking sequences of I/S clays in the ash beds are notably facies-dependent: mainly R3 with minor R1 in deep-marine facies, mainly R1 in shallow-marine facies, and mainly R3 in lacustrine and paludal facies. Ordering of I/S clays seems to have been controlled by porewater K+ availability, solution pH, and energy levels of the depositional environment. High-pH conditions favored the formation of feldspar and inhibited the illitization of smectite, and loss of K+ during early alteration of ash was related to environmental energy levels. However, the stacking sequences of I/S clays in terrestrial facies were dominantly controlled by burial conditions. The MgO and K2O contents of altered volcanic ash were related to sediment clay-mineral composition and thus also facies-dependent. Marine-facies ash beds contain relatively more MgO (i.e., MgO/K2O > 0.30; MgO/Al2O3 > 0.056) than terrestrial-facies ash beds (MgO/K2O Rare earth elements (REE) generally exhibit little variation within a single section but strongly facies-dependent distributions across South China. The REE distributions of deep- and shallow-marine ash beds are similar, characterized by enrichment of light REEs, slight depletion of heavy REEs, and negative Eu anomalies. The REE distributions of terrestrial ash beds are notably different, with weak negative Eu anomalies in lacustrine facies and little to no Eu anomaly in paludal facies. REE distributions can be influenced by adsorption-desorption processes on clay minerals and by dissolution-precipitation reactions involving accessory minerals. Thus, the use of REE patterns of volcanic ashes as fingerprints of source-magma chemistry must take into consideration their sedimentary and diagenetic histories. Trace elements such as Nb, Cu, Zn, Co, Cr, Ta, Mo, V, La, Th, and U exhibit different concentration patterns between ash samples of different facies and even between samples from a single section. Devitrification of volcanic glass to clay minerals can lead to redistribution of TiO2, which shows a close association with the clay fraction of altered ash beds, especially in terrestrial facies. TiO2/Al2O3 ratios of felsic ashes reflect the effects of physical reworking and chemical alteration. It is proposed that TiO2/Al2O3 values 0.140 of strong secondary overprints. The use of Zr/TiO2 vs Nb/Y diagrams for source rock discrimination must take into account such reworking and alteration processes. In terrestrial and shallow-marine facies in which ash-bed reworking is common, the ratios of immobile elements of the clay fraction can still indicate magma source within the range of sensitivity afforded by empirical discrimination diagrams.

Regolith, or in situ weathered material overlying bedrock, develops through pedogenic processes such as clay-mineral formation (“argillization”). Research on products of argillization, such as kaolin, is commonly focused on its economic value rather than on an integrated understanding of the pedological, mineralogic, and geochemical processes taking place in the regolith. Here, we analyzed three kaolin-regolith drillholes from a subtropical climate zone in southern China using X-ray diffraction (XRD), major and trace element analyses, H and O isotopes, differential thermal-thermogravimetric analysis (DTA-TG), and scanning electron microscopy (SEM). Many kaolinite aggregates within regolith have fan-shaped stacks, a morphology that is closely associated with transformation of muscovite plates. Hypogene indicators such as a shallow level of granite emplacement, representative structural controls on kaolinization, mineral zoning, and hypothermal minerals cannot be observed. Mineral assemblages and morphologies, elemental binary plots (e.g., Zr vs. TiO2 and P2O5 vs. SO3), as well as chemical profiles all show characteristics typical of surfical weathering. The δ18O and δ2H values of the clay fractions range from +16.8 to +18.7‰ and from −70 to −51‰, respectively, suggesting that supergene weathering has played a key role in forming the kaolin regolith. Dominance of kaolinite over halloysite implies a near-surface, freely draining environment. Adopting the underlying weakly altered granite (saprolith) as the parent material, the kaolin regolith exhibits four elemental profile patterns as revealed by mass transfer coefficients: (1) depletion (e.g., Na), (2) depletion-enrichment (e.g., Al), (3) enrichment (e.g., Mn), and (4) biogenic (e.g., Ca). These profiles reflect a combination of chemical, geologic, and biologic processes that are typical of relatively thin, in situ regolith profiles, and that is not necessarily similar to those typically associated with deep (thick) granite weathering profiles. We propose that supergene kaolin regolith is intrinsically more similar to shallow, biologically active residual soil deposits, rather than deeply weathered granite-hosted regoliths.

This study explores the use of alkaline pretreatments to improve the hydrolyzation of rice husks to produce volatile fatty acids (VFAs). The study investigated the effects of reagent concentration and pretreatment time on protein, carbohydrates, and dissolved chemical oxygen demand (SCOD) dissolution after the pretreatment. The optimum alkaline pretreatment conditions were 0.30 g NaOH (g VS)−1, with a reaction time of 48 h. The experimental results show that when comparing the total VFA (TVFA) yields from the alkaline-pretreated risk husk with those from the untreated rice husk, over 14 d and 2 d, the maximum value reached 1237.7 and 716.0 mg·L−1 with acetic acid and propionic acid and with acetic acid and butyric acid, respectively. After the alkaline pretreatment, TVFAs increased by 72.9%; VFA accumulation grew over time. The study found that alkaline pretreatment can improve VFA yields from rice husks and transform butyric acid fermentation into propionic acid fermentation. The study results can provide guidelines to support the comprehensive utilization of rice husk and waste treatment.

Hydrogen sulfide (H2S), known as a gaseous signaling molecule, can regulate the intracellular redox status and some crucial signaling processes in the human system. Due to the intricacy of physiological reactivity and rapid catabolism of H2S in biosystems, rapid and efficient methods to monitor H2S in vivo and in vitro are highly desired. With this goal, we herein report an ultrafast fluorescent probe, CA, which was developed for the real-time detection of H2S with high sensitivity and good selectivity. CA displayed a 217-fold fluorescence enhancement in response to H2S with a detection limit of 3.5 nM. With the assistance of a confocal fluorescence microscope, we demonstrated that the probe could be applied for monitoring H2S in living cells and in zebrafish.

Changes in sediment composition in the Xunhua Basin provide insights into the climatic and tectonic evolution of the northeastern Qinghai-Tibetan Plateau during the Oligocene and Miocene. Here, we analyzed the clay mineralogy (i.e., the proportions of smectite, illite, and chlorite and clay indicators), bulk mineral composition (i.e., the amounts of calcite, quartz, gypsum, K-feldspar, plagioclase, dolomite, and halite), and trace-element indicators (i.e., Rb/Sr and Ba/Sr ratios) of sediments deposited from ~28 to 13 Ma in the Xunhua Basin to reveal the climate and/or provenance changes. The results suggest that significant changes in sediment provenance occurred at 25.1 Ma and 21.6 Ma, caused respectively by initial uplift and accelerated uplift of the Laji Shan. The Xunhua Basin experienced warm and humid conditions at 28.0–25.1 Ma, cool and dry conditions at 25.1–21.6 Ma, and somewhat warmer and wetter conditions at 21.6–19.2 Ma, followed by aridification in two steps at 19.2 Ma and 13.9 Ma. The climate cooling event at 25.1 Ma corresponds temporally to a major phase of uplift of central Tibet. Relatively warmer and wetter conditions during the early Miocene (21.6–19.2 Ma) are considered to record the influence of the Asian summer monsoon and accelerated uplift of the Laji Shan. The shift toward more arid conditions on the northeastern Qinghai-Tibetan Plateau at 19.2–13.9 Ma was probably driven by uplift of the Tibetan Plateau, and further aridification since 13.9 Ma may reflect a weakening of the East Asian summer monsoon and global climatic cooling.

The mineralogy and chemical composition of the Jiujiang red soil sediments were investigated using X-ray diffraction (XRD), X-ray fluorescence (XRF), and inductively coupled plasma mass spectrometry (ICP-MS). Mixed-layer illite–vermiculite (I/V) was confirmed based on the conditions that a broad peak of 1.0 to 1.4 nm appeared in XRD after Mg-saturation, and its d-spacing did not change after glycol treatment, but collapsed to 1.0 nm after heating, owing to the loss of water and hydroxy-cations from its interlayer. The mixed-layer I/V contents fluctuate throughout the section but show a decreasing trend upwards, suggesting decreased weathering towards the surface of the section. The chemical index of alteration (CIA) values and Rb/Sr ratios also exhibit upward decreasing trends, jointly revealing the climate shift from warm/humid to cool/dry from the Middle to the Late Pleistocene. Although the general climate evolution can be evaluated by CIA values and Rb/Sr ratios, sub-climatic events within the Jiujiang red soil sediments cannot be identified. The SiO2/Al2O3, Al2O3/Fe2O3, and SiO2/Fe2O3 ratios clearly fluctuate along the section, especially within the net-like red soil sediments, but they do not reveal multiple climate cycles. This is because of an inhomogeneous distribution of SiO2, Al2O3, and Fe2O3 in the white veins and the red matrix and also non-uniform sampling. The variation in the content of mixed-layer I/V show a strong positive correlation with changes in magnetic susceptibility of loess-paleosol sediments and in marine oxygen isotope ratios, revealing multiple sub-climate cycles on a global scale since the Middle Pleistocene. Therefore, the mixed-layer I/V contents not only reveal the whole climate trend documented in the red soil sediments since the Middle Pleistocene, but also disclose the sub-climate cycles related to the deposit-pedogenesis process.

The Bose Basin in southern China is within a region influenced by the winter westerly monsoon and, thus, potentially subject to eolian dust accumulation. A red earth sequence developed on terraces of the Youjiang River (a branch of the Pearl River) records information about climate variation during the Pleistocene and its relationship to contemporaneous global climate changes. In this study, geochemical characteristics and U-Pb geochronology of detrital zircons of the red earth sequence at Xiaomei were investigated using X-ray diffraction (XRD), X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS), thermal ionization mass spectrometry (TIMS), and detrital zircon U-Pb dating analyses. Our results show that the red earth sediments are composed of quartz and clay minerals (kaolinite, illite, and mixed-layer illite/vermiculite) with minor hematite and goethite. Mobile elements such as CaO, MgO, Na2O, K2O, Sr and Ba are depleted and immobile elements such as TiO2, Al2O3, Fe2O3(t) and Zr are enriched in comparison with loess-paleosols of the Chinese Loess Plateau (CLP), the upper continental crust (UCC), and post-Archean Australian shale (PAAS). These data indicate that the Xiaomei red earth sediments have experienced intense chemical weathering, similar to that of the Xuancheng and Jiujiang red earth sections on the middle to lower reaches of the Yangtze River. The Xiaomei sediments have similar La/Th ratios, U/Pb vs. Th/Pb relationships, and rare earth element (REE) distributions to the CLP, UCC, and PAAS, and their low eNd(0) values are indicative of an upper crustal origin. The 147Sm/144Nd and 87Sr/86Sr ratios of the Xiaomei sediments are different from loess-paleosols of the CLP but similar to those of well-mixed river sediments. U-Pb dating of detrital zircons in the Xiaomei sediments shows that crystals from different units have slightly different age distributions. The full Xiaomei section yields a distribution similar to that of Upper Permian-Triassic clastic rocks in the Youjiang area, and the distribution of the middle to upper Xiaomei section additionally shows similarities to upper crust of the South China Craton. Our results indicate that the Xiaomei red earth sequence, which dates to the late Early to early Middle Pleistocene (~ 1.0–0.6 Ma), accumulated predominantly from fluvially transported, locally weathered materials and, therefore, that the sediment-carrying capacity of the East Asian winter monsoon has been overestimated in previous provenance studies of red earth sediments in South China.

This paper presents a case of Gaojiayuan subway station of Beijing Subway Line 14 constructed using combined shield and shallow tunnelling method. The layout, geological and hydrogeological conditions, construction process and related measures to accelerate construction speed and safeguard ground stability of the station are illustrated. The ground surface settlements of the subway station due to construction were systematically monitored. The monitoring results showed that the surface settlements were mainly caused by shield tunnelling, side drifts excavation and double arch excavation. The surface settlement above the station crown of a cross section induced by the above-mentioned three construction stages accounted for about 3.45–7.28%, 35.65–45.54%, 51.01–57.40% of the total settlement value. Limit surface settlement was produced due to the installation of jet grouting columns and cast-in-place piles, and the settlement could be effectively controlled after the completion of pile-beam-arch-wall system. It is noted that grouting can effectively compensate the ground loss and heave the ground accordingly. Moreover, due to the inherent complexity of the subway station construction, the surface settlement curve in a section fluctuated and no longer followed the Gaussian distribution.

Hydrogen peroxide, one of the curial reactive oxygen species, is believed to involve in a wide range of physiological processes. In this work, we designed and synthesized a new fluorescent probe, HKB, for the detection of hydrogen peroxide, by taking advantage of the combination of ICT and ESIPT mechanisms. Different from other benzothiazole-based ratiometric probes, the intramolecular ESIPT process is preserved in probe HKB and the large Stokes shift is remained. Probe HKB displayed significant ratiometric fluorescence variations (I594nm/ I666nm) upon the addition of 50 equiv. of hydrogen peroxide under a single-wavelength excitation at 440 nm in PBS buffer (pH = 7.0, 10 mM, 30% CH3CN) and showed a large Stokes shift change from 102 nm to 254 nm. Moreover, this probe exhibited excellent mitochondria targeting property with a 0.94 Pearson’s colocalization coefficient using Rh123 as a reference. Gratifyingly, preliminary biological experiments indicated that probe HKB could sense both the exogenous and endogenous hydrogen peroxide in living HeLa cells.

Visible-to-shortwave infrared reflectance (VSWIR) spectroscopy is a fast and efficient approach for estimation of soil properties. In order to test whether soil weathering intensity can be predicted using reflectance spectra in the VSWIR range (350–2500 nm), and to examine the efficacy of this methodology to supplement or substitute for traditional mineralogical and geochemical techniques of paleoclimate reconstruction, we investigated a Quaternary soil sequence at Shengli in the Sichuan Basin of southwestern China. VSWIR absorption bands can be characterized by geometrical parameters including position (P), depth (D), width (W), asymmetry (AS), and full width at half maximum (F). Our results indicate that spectral features in the visible-to-near-infrared (VNIR; 350–1000 nm) range can be interpreted in terms of the presence and/or concentration of individual Fe-oxide phases. Spectrally detected water is mostly bound in clay minerals, and this single dominant water source facilitates interpretation of shortwave infrared (SWIR; 1000–2500 nm) parameters. Soil spectral parameters were compared with the Fe-oxide mineralogy, major element composition, and clay mineralogy of soil samples obtained from conventional laboratory analyses. Strong correlations are found between VNIR parameters and Fe-oxide mineralogy, with D 900 serving as the best proxy for total ferric iron concentration. P 900 and D 700 /D 500 exhibit similar variation trends and relationships to the hematite/(hematite + goethite) [H/(H + G)] ratio of soil samples, confirming their value as monsoonal weathering intensity proxies. Lower values of P 900 and D 700 /D 500 indicate warmer and seasonally drier pedoenvironments, reflecting a stronger East Asian summer monsoon. The utility of some SWIR parameters for assessment of weathering intensity declines in inhomogeneous soils (e.g., those having vermiform structure). Thus, spectral evaluation of weathering intensity is most effective in soils that are relatively homogeneous, for which weathering degree is highly correlated to AS 2200 , D 2200 /D 1900 , and AS 1400 . The utility of these spectral proxies depends mainly on the mineral composition of soils and the application type (i.e., laboratory versus field studies). The application of VSWIR in the field (e.g., imaging spectroscopy, or IS) shows promise for rapid, in-situ mapping of weathering intensity, thus providing a convenient approach to paleoclimate reconstruction in remote and inaccessible regions.

The COVID‐19 pandemic, induced by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has caused great impact on the global economy and people's daily life. In the clinic, most patients with COVID‐19 show none or mild symptoms, while approximately 20% of them develop severe pneumonia, multiple organ failure, or septic shock due to infection‐induced cytokine release syndrome (the so‐called “cytokine storm”). Neutralizing antibodies targeting inflammatory cytokines may potentially curb immunopathology caused by COVID‐19; however, the complexity of cytokine interactions and the multiplicity of cytokine targets make attenuating the cytokine storm challenging. Nonspecific in vivo biodistribution and dose‐limiting side effects further limit the broad application of those free antibodies. Recent advances in biomaterials and nanotechnology have offered many promising opportunities for infectious and inflammatory diseases. Here, potential mechanisms of COVID‐19 cytokine storm are first discussed, and relevant therapeutic strategies and ongoing clinical trials are then reviewed. Furthermore, recent research involving emerging biomaterials for improving antibody‐based and broad‐spectrum cytokine neutralization is summarized. It is anticipated that this work will provide insights on the development of novel therapeutics toward efficacious management of COVID‐19 cytokine storm and other inflammatory diseases., Enabled by recent advances in materials science and nanotechnology, emerging biomaterials hold great potential to provide better solutions for COVID‐19 cytokine storm and other inflammatory diseases. By reviewing the state‐of‐the‐art cytokine neutralization systems and highlighting the promising technology development, this work intends to spark further research and development activity in this critical research area.

A super-span tunnel that has the characteristics of a large excavation area, a small high-span ratio and a significant spatial effect exhibits a complex mechanical response during the excavation process. In this paper, taking the Badaling Great Wall station in Beijing, China as the engineering background, a case study of field monitoring a super-span tunnel has been presented. A typical monitoring section was selected in the super-span transition section of the tunnel and the deformation and forces of both the surrounding rock and the support structures were systematically monitored. The dynamic evolution and the spatial distribution characteristics of the monitoring data, including the internal displacement of the surrounding rock, the tunnel displacement, the contact pressure between the surrounding rock and the primary supports, the contact pressure between the primary and secondary supports, the axial forces in the bolts and cables, the internal forces in both the steel arches and the secondary supports and the internal stresses of the surrounding rock, were analyzed. The results of the monitoring and the analyses have shown that the deformation and the forces acting on both the surrounding rock and the tunnel&rsquo, s lining are directly related to the construction procedures, the geological conditions and the locations in the super-span tunnel. According to the results, a few suggestions to improve the construction of the tunnel have been proposed.

Immunomodulation of macrophages against cancer has emerged as an encouraging therapeutic strategy. However, there exist two major challenges in effectively activating macrophages for antitumor immunotherapy. First, ligation of signal regulatory protein alpha (SIRPα) on macrophages to CD47, a "don't eat me" signal on cancer cells, prevents macrophage phagocytosis of cancer cells. Second, colony stimulating factors, secreted by cancer cells, polarize tumor-associated macrophages (TAMs) to a tumorigenic M2 phenotype. Here, it is reported that genetically engineered cell-membrane-coated magnetic nanoparticles (gCM-MNs) can disable both mechanisms. The gCM shell genetically overexpressing SIRPα variants with remarkable affinity efficiently blocks the CD47-SIRPα pathway while the MN core promotes M2 TAM repolarization, synergistically triggering potent macrophage immune responses. Moreover, the gCM shell protects the MNs from immune clearance; and in turn, the MN core delivers the gCMs into tumor tissues under magnetic navigation, effectively promoting their systemic circulation and tumor accumulation. In melanoma and breast cancer models, it is shown that gCM-MNs significantly prolong overall mouse survival by controlling both local tumor growth and distant tumor metastasis. The combination of cell-membrane-coating nanotechnology and genetic editing technique offers a safe and robust strategy in activating the body's immune responses for cancer immunotherapy.

Recent evidence suggests a role of type II collagen in Kashin-Beck disease (KBD) degeneration. We aimed to assess the abnormal expression of heat shock protein 47 (HSP47) which is associated with a decrease in type II collagen and an increase in cartilage degradation in KBD. Hand phalange cartilages were collected from KBD and healthy children. Rats were administered with T-2 toxin under the selenium (Se)-deficient diet. ATDC5 cells were seeded on bone matrix gelatin to construct engineered cartilaginous tissue. C28/I2 and ATDC5 cells and engineered tissue were exposed to different concentrations of T-2 toxin with or without Se. Cartilage degeneration was determined through histological evaluation. The distribution and expression of type II collagen and HSP47 were investigated through immunohistochemistry, western blotting, and real-time PCR. KBD cartilages showed increased chondronecrosis and extracellular matrix degradation in deep zone with decreased type II collagen and HSP47 expression. The low-Se + T-2 toxin animal group showed a significantly lower type II collagen expression along with decreased HSP47 expression. Decreased type II collagen and HSP47 in C28/I2 and ATDC5 cells induced by T-2 toxin showed a dose-dependent manner. Hyaline-like cartilage with zonal layers was developed in engineered cartilaginous tissues, with decreased type II collagen and HSP47 expression found in T-2 toxin-treated group. Se-supplementation partially antagonized the inhibitory effects of T-2 toxin in chondrocytes and cartilages. HSP47 plays a role in the degenerative changes of KBD and associated with T-2 toxin-induced decreased type II collagen expression, further promoting matrix degradation.

Polyhydroxyalkanoates (PHAs) are a potential substitute for traditional plastics. Synthesis of PHAs using excess sludge without additional domestication as a mixed microbial culture can reduce production costs. PHAs were synthesized using excess sludge (R1) from a continuous flow system performing simultaneous nitrification/denitrification and phosphorus removal. Excess sludge (R2) from a A2O wastewater treatment plant was used as a mixed microflora culture (MMC) and the waste fermentation liquid was used as a carbon source. Results showed that with volatile fatty acid (VFA) concentrations of 430–520 mg/L (COD of 650–750 mg/L), when R1 and R2 were reacted under anaerobic conditions, the maximum generated concentrations of PHAs were 84.41 mg/g and 30.8 mg/g, respectively. When aeration volumes were 5, 10, 15, and 20 L/h, the amounts of PHAs synthesized from R1 and R2 increased by varying degrees, with the highest amount generated at 10 L/h (108.6 mg/g and 58.58 mg/g, respectively). In the process of PHA formation, ORP shows a decreasing trend. When the concentration of PHAs reaches a maximum level, ORP drops to a “valley point.” Lower ORP valley points indicate a higher potential for synthesis of PHAs. Therefore, ORP can be used as a control parameter to reflect the reaction process in the micro-oxygen synthesis of PHAs.

Summary Plastid-encoded genes are coordinately transcribed by the nucleus-encoded RNA polymerase (NEP) and the plastid-encoded RNA polymerase (PEP). Resulting primary transcripts are frequently subject to RNA editing by C-to-U conversions at specific sites. The physiological role of many editing events is largely unknown. Here, we have used the CRISPR/Cas9 technique in rice to knock out a member of the PLS-DYW subfamily of pentatricopeptide repeat (PPR) proteins. We found that OsPPR16 is responsible for a single editing event at position 545 in the chloroplast rpoB mRNA, resulting in an amino acid change from serine to leucine in the β-subunit of the plastid-encoded RNA polymerase. In striking contrast to loss-of-function mutations of the putative orthologue in Arabidopsis, which were reported to have no visible phenotype, knock-out of OsPPR16 leads to impaired accumulation of RpoB, reduced expression of PEP-dependent genes and a pale phenotype during early plant development. Thus, by editing the rpoB mRNA, OsPPR16 is required for faithful plastid transcription, which in turn is required for chlorophyll synthesis and efficient chloroplast development. Our results provide new insights into the interconnection of the finely tuned regulatory mechanisms that operate at the transcriptional and post-transcriptional levels of plastid gene expression.

In this study, the effects of inoculating Saccharomyces cerevisiae (S. cerevisiae) on the production of volatile fatty acids (VFAs) via anaerobic fermentation of organic solid waste peanut meal were investigated. At 35°C (temperature of the medium), inoculums consisting of six different S. cerevisiae-peanut meal ratios were used in sequencing batch anaerobic fermentation, and the changes in VFA, protein, glycogen, pH, NH4+, and soluble chemical oxygen demand (SCOD) levels during the fermentation process were studied. Results showed that after inoculation with S. cerevisiae, the anaerobic fermentation of peanut meal mainly produced even-chain VFAs (acetic acid and n-butyric acid); in the early stage of fermentation, inoculation of S. cerevisiae enhanced protein dissolution efficiency and degradation rate, and completely degraded soluble glycogen. The utilization ratio of the protein and soluble glycogen improved. Analysis of significant difference showed that compared to the peanut meal control, the experimental group correlated significantly with the VFAs. The VFA obtained with the inoculum: peanut meal ratio of 0.15 g g−1 was mainly acetic acid, with peak concentration of 10,797.09 mg L−1, which was 1.82 times higher than that obtained with only the peanut meal fermentation. Response surface methodology predicted that the inoculation ratio was 0.15 g g−1, and the effect of producing VFAs was the best when the fermentation time was 8.63d. The results showed that S. cerevisiae inoculation may improve VFA production and increase the proportion of even acids.

This paper presents a case of Chongwenmen subway station of Beijing Subway Line 5 excavated below the existing Line 2, which was the first project of new subway construction below existing subway in Beijing. The minimum clearance between the new and the existing tunnels was 1.98 m. The layout, the geological and hydrogeological conditions, the construction process, and the monitoring measures are introduced. During construction, the maximum settlement of the existing tunnels reached 31.3 mm and the speed of trains run inside the existing tunnels was slowed down. In order to compensate the settlement of the existing tunnels and ensure the operational safety of the trains running inside the existing tunnels, compensation grouting was adopted. The pillar between the existing and the new tunnels was strengthened by grouting first. Then the pillar and the existing tunnels were uplifted together by specific controlled grouting pressure. The compensation grouting successfully uplift the existing tunnels. Moreover the subsequent settlements of the existing tunnels were small as the pillar had been sufficiently reinforced.

With the development of urban subway, there are more projects of new subway construction below existing subway. The project is more challenging if the new subway is excavated below the existing subway with no pillar in between. In this research, we propose an analytical solution to investigate the mechanical responses of the existing tunnel due to new tunnel construction below without clearance. We put forward a superposition method based on the Winkler model to simulate the absence of the springs under the existing tunnel at the intersection of the new and existing tunnel. The proposed solution is successfully validated by FEM simulation. The influences of the input parameters of the model, including the range of deleted springs, the coefficient of subgrade reaction, and the equivalent bending stiffness, on the deflection and the bending moment of the existing tunnel, are studied. The research can serve as a reference to ensure both the safety and the serviceability of existing tunnels in case of new tunnelling below existing tunnel without clearance.

Assays toward single-cell analysis have attracted the attention in biological and biomedical researches to reveal cellular mechanisms as well as heterogeneity. Yet nowadays microfluidic devices for single-cell analysis have several drawbacks: some would cause cell damage due to the hydraulic forces directly acting on cells, while others could not implement biological assays since they could not immobilize cells while manipulating the reagents at the same time. In this work, we presented a two-layer pneumatic valve-based platform to implement cell immobilization and treatment on-chip simultaneously, and cells after treatment could be collected non-destructively for further analysis. Target cells could be encapsulated in sodium alginate droplets which solidified into hydrogel when reacted with Ca2+ . The size of hydrogel beads could be precisely controlled by modulating flow rates of continuous/disperse phases. While regulating fluid resistance between the main channel and passages by the integrated pneumatic valves, on-chip capture and release of hydrogel beads was implemented. As a proof of concept for on-chip single-cell treatments, we showed cellular live/dead staining based on our devices. This method would have potential in single cell manipulation for biochemical cellular assays.

The mineral-bound organic matter (OM) in soils is of great importance for the global carbon cycle. Long-standing debate exists regarding the mechanisms of soil organic matter (SOM) preservation and, especially, the role of organo-clay mineral associations. Investigation of such associations is rarely undertaken in peat soils. In this study, we examine organo-clay relationships in the Dajiuhu peat soil in Hubei Province, central China, based on molecular markers, which allows for understanding of rates of OM degradation and the preservation of OM associated with clay minerals. We analyzed the major and trace element chemistry, clay mineralogy, and lipid compositions of both the coarse- and clay-sized fractions of the soil. The uniformity of trace element and REE distribution patterns in the soil (except for Layer 2) suggests that the source materials were well mixed. Chemical index of alteration (CIA) values of 70–85 indicate moderate to strong weathering processes. A significant correlation between Corg:P and TOC may indicate that redox conditions were a significant control on OM preservation. The clay fraction of Dajiuhu peatland soils also has played an important role in preserving OM, especially in anoxic environments. Fourier transform infrared spectrophotometry (FTIR) and X-ray diffraction (XRD) analysis show that OM is absorbed mainly on the edges of illite grains rather than in interlayer sites. The amphoteric margins of illite crystals allow them to more effectively bind organic compounds. The high Rl/h ratio, high carbon preference index (CPI), and high ratio of unsaturated-to-saturated fatty acids (C18:2/C18) in the clay-sized fraction provide further biomarker evidence that illite efficiently protects OM from biodegradation, thus enhancing the OM content of soils.

A thiocoumarin dye, Probe 1, has been developed for the detection of hypochlorite anion (ClO−) via the desulfurization of thiocoumarin. The heavy atom effect efficiently quenched the fluorescence of Probe 1. Upon the addition of ClO−, Probe 1 was instantaneously oxidized into its oxo form, resulting in a strong yellow fluorescence with an emission maximum at 552 nm and a large Stokes shift (141 nm). This probe exhibited excellent selectivity toward ClO− over other reactive oxygen species, common metal ions and anions. Gratifyingly, the typical desulfurizing agents such as Hg2+ and Ag+ had little interfering effect on the behavior of Probe 1 for the detection of ClO−. This probe dispalyed a low detection limit (1.7 × 10−7 M). Importantly, the application of this probe for the detection of endogenous ClO− in living cells had been successfully demonstrated.

Permian-Triassic (P-Tr) altered volcanic ashes (tuffs) are widely distributed within the P-Tr boundary successions in South China. Volcanic altered ashes from terrestrial section-Chahe (CH) and marine section-Shangsi (SS) are selected to further understand the influence of sedimentary environments and volcanic sources on diagenetic alterarion on volcanic tuffs. The zircon 206Pb/238U ages of the corresponding beds between two sections are almost synchronous. Sedimentary environment of the altered tuffs was characterized by a low pH and did not experience a hydrothermal process. The dominant clay minerals of all the tuff beds are illite-smectite (I-S) minerals, with minor chlorite and kaolinite. I-S minerals of CH (R3) are more ordered than SS (R1), suggesting that CH also shows a higher diagenetic grade and more intensive chemical weathering. Besides, the nature of the volcanism of the tuff beds studied is derived from different magma sources. The clay mineral compositions of tuffs have little relation with the types of source volcanism and the depositional environments. Instead, the degree of the mixed-layer clay minerals and the REE distribution are mainly dependent upon the sedimentary environments. Thus, the mixed-layer clay minerals ratio and their geochemical index can be used as the paleoenvironmental indicator.

A lined tunnel in a semi-infinite alluvial valley with an elastic-slip interface is constructed, and the dynamic stress distribution around the circular tunnel subjected to SH waves is analyzed. The elastic-slip interface model is introduced to simulate the actual interface condition. The Green's function is used to derive the wave fields of incident, scattered, and refracted waves. The elastic and slip coefficients are used to describe the interface properties. The displacement contours and dynamic stresses with different interface coefficients are analyzed. The interface effects under different wave frequencies and embedded depths are also examined in detail.

The slurry type shield method is an important tunnelling method, especially for underwater tunnels in soft soil. If the slurry pressure is too high, it may lead to slurry fracturing of the stratum in front of the excavation face and cause water inrush accidents. Controlling the face stability of shallow shield tunnels is difficult owing to the inadequate understanding of the slurry induced fracturing mechanism. Most importantly, understanding the details of the slurry fracturing propagation process is not enough, as the process is especially complicated. However, the propagation process cannot be directly observed in the field or in small-scale laboratory tests because it occurs in bodies of soil. Thus far, an effective approach to investigate the slurry fracturing mechanism in the surrounding stratum of a slurry shield tunnel has not been reported. In this paper, a numerical simulation method for evaluating tunnelling-induced slurry fracturing is presented. The developed numerical model considered the couplings of stress distribution, fluid flows, and fracturing. The fracture initiation, branching, and propagation in the stratum could be reproduced numerically. A series of simulations for different ratios of cover depth to tunnel diameter were carried out to investigate the propagation process of slurry fracturing. The effects of slurry pressure at the tunnelling face and the cover depth above the tunnel were investigated. The results of the fracturing process induced by slurry, such as the fracture propagation velocity, slurry pressure distribution along the fracture, fracture initiation pressure, fracture extending pressure, and stratum deformations, were analyzed.

To understand climate changes recorded in the Luochuan loess-palaeosols, Shaanxi province, northwestern China, clay mineralogy was studied using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM) methods. XRD results show that clay mineral compositions in the Luochuan loess-palaeosols are dominantly illite, with minor chlorite, kaolinite, smectite, and illite-smectite mixed-layer clays (I/S). Illite is the most abundant species in the sediments, with a content of 61%–83%. The content of chlorite ranges from 5%–22%, and the content of kaolinite ranges from 5%–19%. Smectite (or I/S) occurs discontinuously along the loess profile, with a content of 0–8%. The Kubler index of illite (IC) ranges from 0.255°–0.491°, and the illite chemical index (ICI) ranges from 0.294–0.394. The CIA values of the loesspalaeosols are 61.9–69.02, and the R3+/(R3+ + R2+ + M+) values are 0.508–0.589. HRTEM observations show that transformation of illite to illite-smectite has occurred in both the loess and palaeosol, suggesting that the Luochuan loess-palaeosols have experienced a certain degree of chemical weathering. The Luochuan loess-palaeosols have the same clay mineral assemblage along the profile. However, the relative contents of clay mineral species, CIA, ICI, and IC values fluctuate frequently along the profile, and all these parameters display a similar trend. Moreover, climate changes suggested by the clay index are consistent with variations in the deep-sea δ18O records and the magnetic susceptibility value, and thus, climate changes in the Luochuan region have been controlled by global climate change.

Ni/PMN-PT thin films were prepared by DC megnetron sputtering, and different sputtering temperatures were applied. The crystalline micro-structure and morphology were characterized by XRD, EDS, VSM and SEM. The magneto-electric properties and adhesion strength were measured by force-magneto-electric measurement system and Nano Test Vantage system. The magnetic hystersis loops indicated that the thin film expressed obvious electric-field modulation effect on magnetic properties. By adjusting the sputtering temperature, the crystalline and magnetic properties in Ni/PMN-PT thin film can be improved significantly. In addition, the scratch behavior showed that the critical load values for cracking and failure were significantly related with the sputtering temperature.

Clay minerals are the most reactive and important inorganic components in soils, but soil mineralogy classifies as a minor topic in soil sciences. Revisiting soil mineralogy has been gradually required. Clay minerals in soils are more complex and less well crystallized than those in sedimentary rocks, and thus, they display more complicated X-ray diffraction (XRD) patterns. Traditional characterization methods such as XRD are usually expensive and time-consuming, and they are therefore inappropriate for large datasets, whereas visible and near-infrared reflectance spectroscopy (VNIR) is a quick, cost-efficient, and nondestructive technique for analyzing soil mineralogic properties of large datasets. The main objectives of this review are to bring readers up to date with information and understanding of VNIR as it relates to soil mineralogy and attracts more attention from a wide variety of readers to revisit soil mineralogy. We begin our review with a description of fundamentals of VNIR. We then review common methods to process soil VNIR spectra and summary spectral features of soil minerals with particular attention to those μm fractions. We further critically review applications of chemometric methods and related model building in spectroscopic soil mineral studies. We then compare spectral measurement with multivariate calibration methods, and we suggest that they both produce excellent results depending on the situation. Finally, we suggest a few avenues of future research, including the development of theoretical calibrations of VNIR more suitable for various soil samples worldwide, better elucidation of clay mineral-soil organic carbon (SOC) interactions, and building the concept of integrated soil mapping through combined information (e.g., mineral composition, soil organic matter-SOM, SOC, pH, and moisture).

A red-emitting fluorescent probe has been developed for the selective and sensitive detection of Hg2+. With the addition of Hg2+, the solution of probe 1 displayed a remarkable fluorescence enhancement (102 fold) with λemmax = 625 nm and a large Stokes shift (150 nm). The detection limit of this probe was as low as 7.1 nM based on S/N = 3. This probe exhibited a good performance in detecting Hg2+ in real water samples, living cells and organisms.

This paper investigated the undrained responses for deep circular tunnels with reinforcement in saturated ground analytically. An idealized model of an axisymmetric tunnel with an initial hydrostatic stress field was proposed. Plane-strain analysis was performed to obtain the ground reaction curves by gradually decreasing the internal support pressure from the initial stress to zero after tunnel excavation. The reinforced ground by full-face grouting was assumed as an equivalent circular region to consider the reinforcement effect. Both of the natural ground and the reinforced ground were assumed as the elastic-perfectly plastic materials satisfying the Mohr-Coulomb yield criterion. The proposed model was used to estimate the efficiency of the reinforcement parameters for a deep underwater tunnel. The analytical results were validated by the numerical results. Results show that as the decrease of internal support pressure, the plastic zone may firstly appear not only in the reinforced ground or in the natural ground, but also appear in the two zones simultaneously. Six forms of different plastic zone distributions were categorized. The ground reaction curve for each form was analyzed and 8 critical support pressures were obtained in the unified theoretical framework for the specific boundary conditions. The present model has advantages in undrained analysis of ground reaction curves for deep tunnels in saturated ground considering the effects of ground reinforcement compared with the classical model.

The estimation of the wave-induced instantaneous liquefaction is particularly important for the design of foundations of offshore structures. Regarding the occurrence of liquefaction in a non-cohesive seabed, most existing studies using constant permeability were found to cause fallacious tensile stresses in the liquefied zone and further pollute the overall pore pressure distribution. A dynamic permeability model was previously presented to mitigate the shortcoming but posed difficulties in the nonlinear convergence. To overcome the shortcoming of the previous studies, this study proposes the concept of modelling the liquefaction-involved wave-seabed interactions as a nonlinear complementarity problem, wherein a Karush–Kuhn–Tucker condition is constructed, based on revisiting the liquefaction criterion most widely applied in ocean engineering. The Lagrange multiplier method and the primal–dual active set strategy are employed to numerically deal with the nonlinear complementarity problem. The performance of the chosen multiplier space is investigated by theoretical analyzing and numerical modelling. Compared with the previous dynamic permeability model, the present model is totally free of extra parameters and precisely fulfills the no-tension requirement. Moreover, the difficulties of dynamic permeability in the nonlinear convergence are overcome and no divergence is observed in the numerical tests.

Tillage-induced surface microrelief (TSM) is commonly thought of as an effective measure to control soil erosion on agricultural lands. The objective of this study is to discuss how rainfall intensity and duration affect the role of TSM in soil erosion. Three rainfall intensities of 60, 90 and 120 mm/h and four rainfall durations of 15, 30, 60 and 90 min for each intensity were investigated. Two slope ranges, corresponding to a gentle slope (5° to 10°) and a steep slope (20° to 25°), were considered. Two different TSMs, consisting of depressions and mounds (DM) and troughs and ridges (TR), were used for testing in a soil box that was 2 m long by 1 m wide. A smooth surface (SS) served as a control. The runoff and sediment reduction benefits (RRB and SRB), represented by the ratios of the difference between the tilled slope and SS to that of SS, were used to quantify the role of TSM in soil erosion. The results showed that DM and TR delayed runoff initiation regardless of rainfall intensity and slope. The TSM RRB and SRB decreased with increasing rainfall intensity, duration and slope. Compared to the SS, the DM RRB decreased from 43% to 6% when the rainfall duration increased from 15 to 90 min, and the TR RRB decreased from 100% to 31% on the gentle slopes; on the steep slopes, the DM and TR RRBs decreased from 24% and 46% to nearly zero when the rainfall duration increased from 15 to 90 min. When rainfall intensity was below 90 mm/h and the duration was shorter than 60 min, DM and TR were effective at controlling soil loss; when the duration increased to 90 min or the rainfall intensity was 120 mm/h, the sediment form DM and TR was much higher than that from SS. In particular, the sediment from DM and TR increased by 114% to 330% when the rainfall intensity was 120 mm/h. This indicates that DM and TR were not effective at controlling soil loss during rainfall with a high rainfall intensity and/or long duration. In addition, TR exhibited greater effectiveness at controlling soil and water loss than DM under the same situations. Therefore, rainfall conditions and slopes are important factors influencing the soil and water conservation benefits of TSMs, and the effectiveness of TSMs on soil erosion reduction needs to be further assessed in conjunction with climate change.