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Nowadays, transition-metal phosphides have been reported to function well in photocatalytic water splitting and possess great potential to substitute traditional noble-metal cocatalysts in the future. Herein, p-type cobalt phosphide (CoP-Co2P) nanomaterials were synthesized by phosphating the solvothermally prepared Co(OH)2 nanoflowers at a low temperature (300 °C). Then, we combined the phosphides with commercial TiO2 through facile mechanical mixing to fabricate a useful noble-metal-free photocatalyst. The phosphating time that had an influence on the composition of phosphides was tuned, and 3 h was an ideal condition after comparison. The cobalt phosphide-modified TiO2 at the optimal weight percentage (nominal 0.5%) exhibited the highest photocatalytic hydrogen rate of approximately 824.5 μmol g-1 h-1 under simulated sunlight irradiation, which was nearly equal to 160 times that of bare TiO2 and 1.7 times that of single CoP-modified TiO2. The CoPx/TiO2 heterojunction interfaces were studied using photoluminescence (PL), time-resolved PL, and photoelectrochemical methods, which revealed that the effective charge separation and transfer accelerated by the built-in electric field of p-n junction contributed significantly to the photocatalytic performance.

A versatile and sensitive quantum dot (QD)-based "signal-off" electrochemiluminescence (ECL) sensing system was constructed using target-initiated dual Mg2+-dependent DNAzyme (MNAzyme) recycling and catalytic hairpin assembly (CHA) amplification strategies. After the cascade amplification, numerous ferrocene-labeled Y-shaped DNA complexes generated on the QD-modified electrode surface. In the presence of hemin, moreover, the terminal sequence of the formed complex could assemble into hemin/G-quadruplex. Therefore, the highly efficient ECL quenching was achieved due to the multiple quenching mechanisms, including electron/energy transfer between ferrocene and QDs, the steric hindrance effects, and the horseradish peroxidase-mimicking activity of hemin/G-quadruplex. Furthermore, owing to the flexibility in regulating the recognition sequences of MNAzyme, the assaying targets can be programmed. Based on the cascade amplification and multiple ECL quenching mechanisms, the developed programmable "signal-off" ECL sensing platform demonstrates excellent sensitivity and the detection limits of 35.00 aM, 3.71 fM, and 0.28 pM (S/N = 3) for target DNA, aptamer substrate (ATP as a model), and ion (Ag+ as a model), respectively.

Novel two-dimensional silicon-based material siloxene has been synthesized handily by a one-step method, which utilizes the characteristics of the topological exfoliation to simplify the process of synthesis and modification. It is worth mentioning that for the first time amino-modified derivative has been investigated. Amino modification can promote the oxidation of siloxene, enlarge the bandgap and extend the carrier lifetime of siloxene. The application of siloxene before and after modification in water-splitting has been investigated. In addition, the superiority of the resultant two-dimensional materials was concisely elaborated, which revealed that owing to more effective photogenerated carriers' separation in amino modification siloxene, hydrogen production could be greatly promoted.

A palladium-catalyzed cross-coupling reaction with aryl halide functionalities has recently emerged as a valuable tool for protein modification. Herein, a new fluorogenic modification methodology for proteins, with genetically encoded fluorosulfate-l-tyrosine, which exhibits high efficiency and biocompatibility in bacterial cells as well as in aqueous medium, is described. Furthermore, the cross-coupling of 4-cyanophenylboronic acid on green fluorescent protein was shown to possess a unique fluorogenic property, which could open up the possibility of a responsive "off/on" switch with great potential to enable spectroscopic imaging of proteins with minimal background noise. Taken together, a convenient and efficient catalytic system has been developed that may provide broad utilities in protein visualization and live-cell imaging.

Fiber-based linear actuators (FLAs) are a key module in microrobots and biomimetic devices. It has been a great challenge to develop linear actuators that can balance output stress and output strain and hence provide high working density. Herein, we report the preparation and performance of a FLA system made from commercially available materials and allowed mass production at relatively low cost. The FLAs can lift up or lay down objects more than 1000 times of its own weight during active contraction and expansion under environmental stimuli. The contraction ratio and output stress can reach 30% and 0.24 MPa, respectively, and the sustainable work density is about 80 J/kg, which is 10 times the typical value of human skeletal muscles. Especially, the FLAs show stable catch-state (lock-up state) with no creeping and no further energy consumption.

n-Alkanes are biomarkers that are widely used as paleoenvironmental reconstruction proxies in lacustrine sediments. However, studies on their sedimentation and factors affecting sedimentation in large lakes remain relatively scarce. In this study, 120 surface sediments collected from Selin Co, central Tibetan Plateau, were used to analyze the spatial distribution of n-alkanes in a modern sedimentary system, and the factors controlling this distribution were further discussed. The sedimentary n-alkanes of Selin Co were mainly long- and middle-chain components with single or double peaks, belonging to the mixed-type input of terrestrial and aquatic plants. Leaf waxes derived from terrestrial plants in the catchment of Selin Co were the main source followed by aquatic plants, while planktonic algae living in the lake water column was a minor source, as demonstrated by their low concentration. The distribution of aquatic and terrigenous n-alkanes in the surface sediments showed a significant spatial heterogeneity; this was controlled by different factors and sedimentary processes. The distribution of terrigenous n-alkanes was mainly controlled by underwater topography; high concentrations in the sedimentary center of the east lake basin and the sub-basin in the northwest were evident. Aquatic n-alkanes were found in substantially higher concentrations in the western estuary of Zhagen River and Ali River, as well as in the southern sub-basin, Yagen Co. These distributions might be influenced by differences of geographical environment in the watershed of these main inflow rivers, as well as the intensity of sunlight, itself intensity controlled by the transparency of the water column. Although n-alkanes from the center of a lake could represent an integration of catchments in most cases, their spatial heterogeneity in large lakes like Selin Co would introduce uncertainty to paleoenvironmental reconstructions. Consequently, it is very important to investigate thoroughly the spatial distribution and controlling factors of n-alkanes in modern lake environments. It is inferred that these findings will have broad significance in large lakes similar to Selin Co, and that they will benefit studies that use n-alkanes as proxies to reconstruct past environmental changes.

Synthetic polymer membranes are widely used in many applications, including, among others, water purification, protein separation, and medicine. However, the use of existing polymer membranes faces major challenges, such as the trade-off between permeability and selectivity, membrane fouling, and poor mechanical strength. To address these problems the authors have focused their research on surface/interfacial tailoring and the structure-property relationship of polymer membranes used in liquid separation systems. Progress has been made as follows: (1) a methodology for membrane surface functionalization and nanofiltration (NF) membrane preparation based on mussel-inspired catecholic chemistry was proposed and established; (2) a class of mechanically robust and environmentally-responsive composite membranes with hydrogel pore-filled in rigid macroporous supports was designed and developed; (3) a methodology for surface tailoring and antifouling modification of polymer membranes based on amphiphilic copolymers was created and the scientific implications for amphiphilic polymer membranes elaborated; (4) an adsorption membrane with both filtration and adsorption functions was designed and developed to achieve rapid removal of trace micropollutants, including heavy metal ions, organic dyes, plasticizer, antibiotics, and others. This mini-review briefly summarizes this work.

Lake monitoring studies are essential for understanding the modern biogeochemical and sedimentological cycles to enable and support the interpretation of paleolimnological records. However, such studies remain scarce for high-altitude lakes in general and specifically for lakes on the Tibetan Plateau. We investigated the hydro-chemical and physical properties of lake Nam Co and its twenty-one major inflowing rivers from 2011 to 2013. The modern sediment flux and sediment properties were determined for samples collected by sediment traps deployed for the same study period at different water depths at three sites in Nam Co. Carbonate weathering in the catchment, especially pronounced during the monsoon season, was identified as the predominant origin of dissolved riverine hydrochemical components. The sediment budget shows remarkable temporal variation, with trends of intensified sediment fluxes during the non-monsoon season and small variations within the monsoon season. Spatially, considerably higher sedimentation fluxes were detected in nearshore sites (T1 and T3) and attributed to wind-induced resuspension. Vertically, resuspension is also an important factor that influences the sedimentation process, which leads to an exponential increase of the budget from the surface to the bottom layer. Autochthonous carbonate deposition rates presented a similar seasonal pattern, with the total sedimentation rates under the influence of the water balance. Low values occurred during the monsoon season due to dilution while deposition rapidly increased during the early post-monsoon season when the lake level decreased. Intensive carbonate deposition also occurred during the non-monsoon season, which dominated the lake hydrochemistry dynamics.

Modern dolomite was found in the sediments of 20 lakes on the central and western Tibetan Plateau during lake surveys, in August to November of 2012–2015. We analyzed the mineralogy of authigenic carbonates and the chemical composition of lake water to investigate the environmental factors affecting dolomite formation and to determine the mechanisms of dolomite formation. X-ray diffraction analysis suggested that the dolomite content ranged from 3% to 10%, with a mean of 5%, and that the majority of the dolomite in the surface lake sediments was Ca-dolomite. Dolomite formed in a wide range of salinity environments. There was a positive linear relationship between salinity and Mg/Ca ratio, whereas the pH and sulfate (SO42−) concentration are not significantly correlated with Mg/Ca ratio. High Mg/Ca ratio, high salinity, high sulfate concentration, and high pH are important environmental factors in favor of dolomite precipitation. Evaporation and microbial activity are potential mechanisms for dolomite formation in the central and western Tibetan Plateau. The positive relationship between δ18O and δ13C indicates that the dolomite formed in lakes has a long residence time and undergoes continuous evaporation. The crystal morphologies of dolomite were scattered euhedral grains with diameters of 2–10 μm, as well as sub-spherical and spherical grains (

The vibration and noise produced by the powertrain and waves inside ship cabins limit working efficiency and crew and passengers’ accommodation quality. This paper simplifies ship cabins as cavities and explores active control techniques to attenuate sound transmission via multiple parallel-supported flexible subplates. The theoretical formulations of the interaction between multiple subplates and cavities were performed and the coupling relationships between them were analyzed. Based on the multiple subplates and the cavity coupling models, numerical simulations were performed using the derived optimal controller to minimize the transmission of sound into the cavities through two and nine parallel-supported subplates. The various control strategies were explored to minimize the coupling system’s acoustic potential energy, and the control performances were compared and discussed. The mechanism of reducing sound transmission through multiple supported subplates into a cavity is revealed. The simulation results showed that the vibration pattern of the controlled subplate is changed after it is regulated, which increases its radiation to subdue the other subplates’ radiation, while increasing vibration of the controlled subplate. The more subplates a cavity has, the more kinetic energy the controlled subplate possess. Furthermore, the noise reduction performance of a cavity with fewer subplates is better than that with more subplates.

Single atom catalyst is of great importance for the oxygen reduction reaction (ORR). However, facile preparation of single atom catalyst without using well-designed precursors or labor-intensive acid leaching remains an urgent challenge. Herein, a simple pyrolysis of Fe3+-loaded mesoporous phenolic resin (mPF)-melamine precursor is used to prepare the single atom iron-anchored N-doped mesoporous graphitic carbon nanospheres (Fe/N-MGN). Investigation of the synthesis reveals the appropriate Fe-assisted catalysis effect and mPF template effect, which not only spurs the highly graphitic porous framework of Fe/N-MGN with plentiful pyridinic N/graphitic N, but also assures the dispersed single atom Fe anchoring without elaborated procedures. As a result, the as-synthesized Fe/N-MGN demonstrates high catalytic activity, good durability and excellent methanol tolerance for ORR. This work promises a facile method to regulate the graphitic carbon growth and single atom Fe loading for the highly efficient electrocatalysis.

The traditional model of grey nearness degree of incidence contains some inherent limitations in the calculation of data sequences. It does not consider the impacts of certain data on degree of incidence when there are significant differences in orders of magnitude between adjacent data in the same sequence, and big errors may occur in the calculation of some special oscillation sequences. In response to these problems, we propose a new improved method, which uses the characteristics of the model of grey nearness degree of incidence and introduces a neural network algorithm to define a grey neural network-nearness degree of incidence. Thereby, a model of nearness degree of incidence is established based on grey neural network. Then we apply a new model to the field of data mining. According to the clustering algorithm, we take all the degrees of incidence as the variables of the distance metric function, and use the clustering algorithm of data mining for data analysis. Finally, through simulation experiments, we verify the effectiveness of the clustering algorithm under the new distance metric definition. The experimental results show that, compared with other methods, the computational outcomes of the improved model are more consistent with the actual situation. The cluster algorithm with the model used can deliver results that have a high accuracy, so the new model can be applicated in a wide range of fields.

In the present work, polydopamine nanotubes (PDA NTs) decorated with silver (Ag) nanoparticles (NPs) were successfully fabricated via a template induced self-polymerization of dopamine, followed by...

The extremely thick sedimentary sequence in the Qaidam Basin, northeastern Tibetan Plateau (TP) is closely related to the uplift of the TP. Due to the scarcity of minerals that can be dated continuously, little is known about the isotopic responses of the minerals in this area to the changes in the weathering and sources over a long time period. A 938.5-m long core (magnetostratigraphic age of ∼ 2.8–0.1 Ma) was drilled in the western Qaidam Basin in 2008. The mineralogy and isotopic compositions of gypsum in this core were investigated. The gypsum recorded the primary information about the brine that formed during ∼ 2.8–0.1 Ma. The variations in the Sr isotopes (0.709817–0.714473, average of 0.711249) and Nd (0.512114–0.512614, average of 0.512184) of the gypsum samples suggest that the weathering products of the rocks in the Kunlun and Altyn mountains (Mts) likely exerted a strong control on the Sr-Nd isotopes of the lakes. The climate and the Sr content/isotopic compositions of the gypsum samples were affected by the regional tectonic activities throughout the evolution of the paleolake since 2.8 Ma. The results of this study demonstrate that Sr-Nd isotopes are useful tools for investigating the origins of evaporite deposits and the interactions between tectonic activities and climate change.

Lakes and glaciers are widely distributed on the Tibetan Plateau and are linked via hydrological processes. They are experiencing rapid changes due to global warming, but their relationships during the Holocene are less well known due to limited coupled geological records. Here, we analyzed the δ13C-VPDB and δ18O-VPDB values and ion content of calcite and aragonite in a 407-cm-long sediment core from Guozha Co, a closed basin on the northwestern Tibetan Plateau supplied by glacial meltwater, in order to understand how the lake responded to glacier changes during the Holocene. Our results indicate that the glacial meltwater lowered the lake’s temperature and the δ18Olake water and δ18Oendogenic + authigenic carbonate values and diluted the ion concentrations in the lake water. Three stages of evolution, 8.7–4.0, 4.0–1.5, and 1.5 kyr BP to present, are distinguished based on the decrease in glacial meltwater recharge. Guozha Co has been a closed basin since at least 8.7 kyr BP, and it has changed from a fresh water lake during 8.7–1.5 kyr BP to a brackish lake from 1.5 kyr BP to present due to several climate events. The famous 4.2 kyr BP cold event was identified in the core at 4.0 kyr BP, while warm events occurred at 6.2, 3.9, 2.2, 0.9, and 0.4 kyr BP. Both glaciers and lakes in this area are controlled by climate, but they exhibit opposite changes, that is, glaciers retreat and lakes expand, and vice versa. Our results provide an accurate interpretation of the cold events based on carbonate minerals and carbon–oxygen isotopes in glacial meltwater–recharged lake sediments.

Measurement of cardiac troponin I in the blood is crucial for the early diagnosis of acute myocardial infarction. Herein, a novel and ultrasensitive electrochemiluminescence (ECL) immunosensor has been developed for determination of cardiac troponin I (cTnI) by using Au nanoclusters and hybridization chain reaction (HCR) signal amplification. In this ECL immunosensor, Au nanoclusters were dual-labeled at each end of hairpin DNA (H

Inspired by the coreactive activity of carbon nanodots (CDs) and branched polyethylenimine (BPEI) toward electrochemiluminescence (ECL) of Ru(bpy)32+, a highly luminescent and self-enhanced ECL nanohybrid (Ru-BCDs) was synthesized through covalently linking BPEI-coated carbon dots (BCDs) with Tris (4,4'-dicarboxylic acid-2,2'-bipyridyl) ruthenium(II) dichloride (Ru(dcbpy)32+). The composition and morphological characterization demonstrated that the spherical Ru-BCDs particles with 12.1 ± 1.4 nm diameter were obtained. The enhanced ECL property of Ru-BCDs was proved to originate from the dual coreactive contribution of BPEI and CDs as coreactants as well as the intramolecular electron transfer process, which could shorten the electron transfer path and minimize energy loss. A carbon nitride nanosheet (CNN) was utilized to stabilize the Ru-BCDs-modified glassy carbon electrode, which greatly improved the stability of solid-state ECL. By utilizing the affinity discrepancy of the CNN to single-stranded and double-stranded nucleic acids, a label-free and signal-on ECL biosensor was constructed for the determination of microRNA-133a (miR-133a), a potential biomarker of acute myocardial infarction. The designed biosensor exhibited good performance of miR-133a detection with a detection limit of 60 fM and could be used for the detection of real human serum with satisfactory results. The self-enhanced ECL nanohybrid with distinguished ECL efficiency holds a promising prospect in biosensing and bioimaging applications.

The incorporation of nanofillers in interfacial polymerization is a promising approach to elevate the permeability of thin-film nanocomposite (TFN) membranes. However, commonly-used inorganic nanomaterials (e.g., silica, zeolites, and carbon nanotubes) often bring defects, and thus low selectivity to the membranes due to their poor interfacial compatibility with polymeric matrix. In this work, organic polydopamine/poly(ethylene glycol) (PDA/PEG) nanocapsules were designed as fillers of the TFN membranes prepared by interfacial polymerization of piperazine with trimesoyl chloride. No aggregation phenomenon was observed for the nanocapsules in the membranes, which is attributed to their good dispersity brought by the grafted PEG brushes on the shells. Defect-free separation layer was obtained for the TFN membranes due to good miscibility of polymeric nanocapsules with polyamide matrix. The inner cavities of the embedded nanocapsules played a role of shortcuts for water permeation through the thin-films. The resultant PDA/PEG-TFN membranes showed a high water permeance of 11.7 L·m−2·h−1·bar−1, approximately 2.2 times that of the control TFC membrane, while maintained high solute rejections (RNa2SO4 = 95% and RVitamin B12 = 98%). Moreover, the PDA/PEG-TFN membranes exhibited high selectivity towards di-/mono-valent salts. This work presents a novel strategy of constructing water transport channels in selective layer to develop high performance nanofiltration membranes.

The Tibetan Plateau has many endorheic lakes which are an important part of the Asia Water Tower. In recent decades, the warming rate of the Tibetan Plateau is two times higher than the global average, and precipitation also has obvious increase. As the largest cryosphere system in the middle and low latitudes, the temperature and precipitation changes in the Tibetan Plateau have profound impacts on the lakes in the region. Before 1990, low temperature caused negative balance of lake water storage by suppressing melting water. In 1990−2000, increase of lake water stoage was promoted by temperature increase. After 2000, precipitation is the dominant factor causing the increase of lake water storage, but the continuous temperature rise in 2005−2013 strengthened evaporation and weakened the increase of lake water storage. Glaciers have different impacts on lake water storage. During the period of 2000−2013, glacier melting water contribution to lake water increase in the central and northwest parts of the Tibetan Plateau is up to 50% and 100%, respectively. Changes in water quantity and salinity are the results of lake water budget under climate change, which are important indicators and their temporal and spatial characteristics may reflect the influence of the westerly and Indian monsoon on land surface water cycle. The trend of the lake water storage in different parts of the Tibetan Plateau from 1970s to 2013 is consistent with that of precipitation in the westerly and Indian monsoon-controlled areas. It is found that with the increase of lake water storage, the salinity of lakes generally decreases in the Serling Co area. The physical and chemical properties of lake water are important factors affecting lake ecosystems, and their changes under different climatic conditions have profound impacts on the composition and trend of lake ecosystems. Increase in water temperature promotes the transmission efficiency of food chain, which leads to high ratio of zooplankton to phytoplankton and low ratio of phytoplankton to total phosphorus. Decrease in lake salinity increases the biodiversity and makes lake ecosystem structure relatively complex. In lakes with salinity of about 3−5 or 25−28 g/L, zooplankton species composition is the most sensitive to salinity change. Based on the analyses of the relationships among lake area, water level, water quantity, water physicochemical parameters and climate changes in the Tibetan Plateau, this paper reviews the research progress on lakes as a response to climate change in the region, and puts forward the main objectives and tasks of the lake research in the Second Tibetan Plateau Scientific Expedition Program.

CO oxidation is one of the most important catalytic reactions and it has to be run at relatively high temperature. Photothermal catalysis system could convert light as heat to drive CO oxidation rather than their conventional counterparts that use only thermal stimulus. But the light intensity required in this photothermal catalysis system is much higher than the solar intensity, restricting the application of photothermal CO oxidation. Here we present a Fe3Si based photothermal converted system to assist Co3O4 rhombus-shaped nanorods catalysts for achieving efficient photothermal CO oxidation just under weak solar irradiation. Based on photothermal experiments, we conclude that Fe3Si based photo-thermal converted system can convert 0.3–0.35 kW m−2 solar irradiation into a temperature as high as 160 °C, 3 times higher than existing photothermal catalytic systems, which able to excite the activity of Co3O4 rhombus-shaped nanorods for complete CO oxidation, solely irradiated by third of standard solar light and outdoor sunlight. The results suggested that the photothermal CO oxidation can be driven by ambient solar irradiation in the presence of Fe3Si based photothermal system and Co3O4 rhombus-shaped nanorods, facilitating for industrial applications.

Machine learning technology has been widely applied in the field of seismic interpretation . In most cases, machine learning assisted seismic interpretation is calibrated or constrained by wells. However, due to the limitation of drilling cost, sometimes there are only a few samples can be obtained from the well-points for a specific layer, which is insufficient to guarantee the generalization ability of supervised learning. In this article, we propose a novelty semi-supervised method by combining the unsupervised isolation forest with split-selection criterion (SCiForest) algorithm and the supervised feature selection process together. The key of the proposed method is to be able to make full use of both the self-contained distribution information of multiple seismic attributes and the calibration information of limited well-points at the same time. To highlight the advantages of the proposed method referred to conventional supervised and unsupervised methods, we take the channel identification practice in the western Bohai Sea as a case study for comparison. Further discussion confirms that the proposed method can improve the visibility of channel effectively by fusing the relevant information in amplitude, frequency, and morphological attributes with limited calibration, which may provide a reliable alternative way for further machine learning assisted seismic interpretation.

Etherification of cellulose can get a series of water soluble derivatives, which can form hydrogen-bonded polymer complex with poly(acrylic acid) (PAA). Three cellulose ethers hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC) and methyl cellulose (MC) are LbL assembled with PAA to fabricate thin films. The hydrogen bonding of the films is characterized with FT-IR. The film growth behaviors are monitored by a quartz crystal microbalance (QCM) and a spectroscopic interferometer, which shows a different growth rate for different system and a strong dependence on pH values. The stability of the films can be increased by heat treatment. Once the cross-linked structure is formed, and the dissolution of film can be prevented even in the high pH value. In addition, the films show good water adsorption ability from environment. Owing to pH responsive behavior and good water adsorption, CE/PAA films can be explored for various applications, especially for biomedical application.

Here, we report the preparation of hydrogen-bonded complex fibers of graphene oxide (GO) and polyethylene oxide (PEO) and their reduction to conductive fiber. The complexation behaviors of PEO and GO at different pH values are investigated. When pH is below 2.0, PEO and GO will form the complex which precipitates out from the solution quickly. When pH is higher than 5.0, GO and PEO mixed solution will be homogenous. At pH 6.0 the GO/PEO solution shows good fluidity and pre-orientation of GO sheets. The solution is extruded into 1.0 M HCl solution where hydrogen bonding between PEO and GO is constructed and hence the fiber forms. After reduction, the fibers show good mechanical and electrical properties, and the mechanical strength is close to 500 MPa while the conductivity is more than 200 S/cm. The reduced fibers can be assembled into flexible supercapacitor, exhibiting potential for wearable electronics.

The complete hydrolysis of poly(2-ethyl-2-oxazoline) (PEOX) produces poly(ethylene imide) (PEI). While PEOX and poly(acrylic acid) (PAA) can form hydrogen-bonded polymer complexes that are precipitated from solution at low pH values, PEI and PAA can form polyelectrolyte complexes in the solutions with neutral pH values. In this work, partially hydrolyzed PEOX (PEOX-EI, hydrolysis degree 60%) and PAA are selected to prepare nanofiltration (NF) membranes. In order to obtain homogenous mixed solutions that are suitable for the membrane preparation, alkaline (NaOH) is precisely added into the system to tune the hydrogen bonding and electrostatic force between the PEOX-EI and PAA chains. FT-IR spectroscopy is applied to investigate the interactions between the PEOX-EI and PAA chains. The rheological behaviors of the homogenous mixed solutions of PEOX-EI and PAA are studied in order to optimize the membrane casting conditions. By taking the advantage of the reaction between the imine groups in PEI chains and terephthaloyl chloride, the cast membranes are further cross-linked to enhance the membrane stability. The NF performance of the complex membrane is then evaluated using methyl blue (MYB) solutions, resulting in a MYB rejection rate of 99.2% and a flux of 55.8 L/m2·h under the pressure of 6 bar.

Chronological analysis is the basic premise for paleoenvironmental research on lake sediment cores. It mainly employs bulk organic matter as a mixed dating material, although terrestrial plant remains are believed to provide reliable radiocarbon (14C) ages. 14C reservoir effects (REs) are generally problematic in establishing a final chronology and are usually recorded in aquatic macrophytes by the incorporation of dissolved inorganic carbon in high-altitude lakes of the Tibetan Plateau. We present a typical case of a 5.48 m-long core sampled from Chibuzhang Co, a lake in north Tibet, China, which contained two obvious obstacles: high REs and age reversals. The 14C RE was recently as much as ∼3500 years in the upper part according to total organic carbon (TOC) 14C ages and related dating from 210Pbex activity. It notably changed during the climatic transition to the Holocene due to carbonate input from catchment erosion and glacial meltwater, resulting in reversed 14C ages in the lower section of the core. 14C-dead carbon (or old carbon) dissolved in lake water was incorporated in the dating materials, as inferred from the 14C ages of plant samples. By combining data on grain size and carbonate content changes, two sedimentary units were identified with a boundary at 390 cm depth. These were used to estimate individual sediment accumulation rates (SARs) for the final age-depth models, instead of using a constant RE-corrected chronology. Our results provide an environmental history of ∼12.7 kyr in a long sediment core, based on an optimized SAR model of conventional 14C ages, which is supported by related lacustrine records and Bacon models. Use of separate 14C SAR analyses can solve the problem of age inversion in sediment cores, as sedimentological chronology analysis.

Background Two-dimensional electrophoresis (2-DE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) are widely used in plant proteomics research. However, these two techniques cannot be simultaneously satisfied by traditional protein extraction methods when investigate cotton leaf proteome. Results Here, we evaluated the efficiency of three different protein extraction methods for 2-DE and LC-MS/MS analyses of total proteins obtained from cotton leaves. The protein yield of the borax/PVPP/phenol (BPP) method (0.14%) was significantly lower than the yields of the trichloroacetic acid/acetone (TCA) precipitation method (1.42%) and optimized TCA combined with BPP (TCA-B) method (0.47%). The BPP method was failed to get a clear 2-DE electrophoretogram. Fifty pairs of protein spots were randomly selected from the 2-DE gels of TCA- and TCA-B-extracted proteins for identification by MALDI TOF/TOF, and the results of 42 pairs were consistent. High-throughput proteomic analysis showed that 6339, 9282 and 9697 unique proteins were identified from the total cotton leaf proteins extracted by the TCA, BPP and TCA-B methods, respectively. Gene Ontology (GO) analysis revealed that the proteins specifically identified by TCA method were primarily distributed in the plasma membrane, while BPP and TCA-B methods specific proteins distributed in the cytosol, indicating the sub-cellular preference of different protein extraction methods. Further, ATP-dependent zinc metalloprotease FTSH 8 could be observed in the 2-DE gels of TCA and TCA-B methods, and could only be detected in the LC-MS/MS results of the BPP and TCA-B methods, showing that TCA-B method might be the optimized choice for both 2-DE and LC-MS/MS. Conclusion Our data provided an improved TCA-B method for protein extraction that is compatible with 2-DE and LC-MS/MS for cotton leaves and similar plant tissues which is rich in polysaccharides and polyphenols. Electronic supplementary material The online version of this article (10.1186/s12864-019-5658-5) contains supplementary material, which is available to authorized users.

Mesoporous Al-doped NiO ultralong nanowires with better uniformity, dispersity and well-defined morphologies were synthesized by a simple surfactant based hydrothermal treatment of aqueous solution of Al(NO3)3, NiCl2 and NaC2O4 in the presence of ethylene glycol and polyethylene glycol through continuous open air heating at 500 °C. The sensing performances of the gas sensor’s based on bare and Al-doped NiO nanowires had been investigated towards ethanol, methanol, acetone, xylene, toluene and benzene. The results specified that the 3.2 at% Al-doped NiO nanowires display better gas sensitivity characteristics as compare to that of undoped, 1.6 at%, 2.1 at% and 4.3 at% Al-doped NiO nanowires. It has been investigated that the sensitivity features were upgraded with an increment on Al concentration into the crystallites based on NiO nanowires. The assimilation of Al3+ ions within NiO crystals modifies the carrier concentration by inducing changes in the chemisorbed and deficient oxygen of NiO nanowires. Hence, the incorporation of Al3+ into NiO nanowires would be a capable way for scheming and devising significant gas sensors.

Glaciers on the Tibetan Plateau are an important freshwater resource for large populations in south and southeast Asia. Therefore, it is important to understand past variations in glacier activity in the region to assess their possible response to ongoing climatic warming. Here, we present the results of analyses of grain size, total organic carbon, pollen ratio (Artemisia to Chenopodiaceae) and the element content of a 435 cm-long sediment core from proglacial lake Buruo Co on the northern Tibetan Plateau. Our results indicate that the Buruo Co catchment experienced relatively warm and humid conditions during 5.2–4.0 cal kyr BP, during which retreating glaciers released large amounts of freshwater. Precipitation was also abundant during this interval as a result of the relatively strong Indian Summer Monsoon and weaker Westerlies and thus the lake level was high. During 4.0–1.3 cal kyr BP, the Westerlies were gradually enhanced and the climate became colder and drier; in response, the glaciers advanced and the lake level decreased. During 1.3–0 cal kyr BP, under relatively cold conditions, a large volume of glacial ice was maintained; nevertheless, under the Westerlies influence, the lake level rose. Four episodes of glacial advance are detected: at 3.6–3.4, 3.2–2.3, 1.9–1.7 and 0.4–0.1 cal kyr BP. These episodes correspond well with Bond events in the North Atlantic, implying that climate change and glacial activity at Buruo Co were largely driven by variations in Northern Hemisphere insolation and by climatic oscillations in the North Atlantic region, via the influence of the Westerlies.

Here, we demonstrated the potential of an ultrathin Mg-rich MgO tunneling layer as a passivation layer for earth-abundant Cu2O based solar cell. An ultrathin Mg-rich MgO layer was introduced to the interface of Cu2O/SnO2 heterojunction by electron beam evaporation, which greatly enhanced the efficiency of Cu2O/SnO2 heterojunction solar cell. The MgO layer was found to significantly reduce the CuO defect density and create a stoichiometry Cu2O surface confirmed by high-resolution X-ray photoelectron spectroscopy. Thus, charge recombination caused by interface defect was mitigated bringing an increased device efficiency. This work highlights the need for stoichiometric Cu2O surface in Cu2O-based solar cells.

Direct measurements of formation properties such as the shale volume, porosity, permeability, and fluid saturation are often accompanied by expensive cost and are time-consuming too. Well logging inversion provides an alternative way for the determination of formation properties. Compared to traditional theoretical models or formalized empirical fitted models, machine learning assisted logging regression modeling is more accurate and objective. Several machine learning regression algorithms such as neural networks, support vector regression, fuzzy logic, k nearest neighbors regression, multivariate adaptive regression spline, and random forest have already been applied. In this article, we present the Linear Random Forest algorithm and investigate its application in logging regression modeling. By systematic comparison with 8 other algorithms including least squared linear regression, neural networks, epsilon support vector regression, k nearest neighbors regression, regression tree, regression random forest, gradient descent boosted trees, and linear decision tree, the advantage of linear random forest in performance is confirmed by 24 real-world tasks from 7 different areas. Deeper discussions reveal that the advantages of linear random forest source from its strong learning ability, robustness, and feasibility of the hypothesis space. Through our study, the superiority of linear random forest for logging regression modeling is substantiated, which provides a more reasonable way for the further practices of logging regression modeling.

Change in lake water storage is an important factor influencing hydrological cycle, regional environment, and climate on the Tibetan Plateau (TP) because of the large number (>1000 lakes) and huge areas (>46,500 km2) of lakes. Due to the lack of in situ lake level monitoring for most lakes, and long-term continuous satellite altimetry data for some large lakes, estimates of water storage changes for all lakes throughout the TP over a long time is challenging. We have estimated the lake water storage changes of 315 lakes (each lake is >10 km2) during the period of 1976–2013 through an empirical equation based on Shuttle Radar Topography Mission (SRTM) DEM (Digital Elevation Model) data and Landsat images. These lakes are located within endorheic basins and occupied approximately 80% of the total lake surface areas of the TP in 2013 based on the results of this study and Zhang et al. (2014). The results showed that the lake water storage decreased by 23.69 Gt from 1976 to 1990 and increased by 140.8 Gt from 1990 to 2013. Increased water storage was mainly concentrated in the central TP (regions A) and northern TP (region B). The increase in total lake surface area during the period 2000–2013 in region B (1981.6 km2) was greater than that in region A (1869.1 km2), but the increase in the water storage in the former was half of that in the latter, indicating that lake surface area changes cannot represent the degree of lake water storage change due to differences in the topography and lake size. Although the total variation in the rate of the lake water storage change (7.19 Gt/y) was similar to the rate of increase in the mass (7 ± 7 Gt/y) estimated from Gravity Recovery and Climate Experiment (GRACE) data for the whole region, the spatial distribution of these variations was largely different. During the period 2000–2013, a trend analysis revealed that precipitation was perhaps the primary reason for lake change throughout the TP, while a decreasing evaporation rate only contributed approximately 1.5%, 2.5% and 1.7% to the expansions of the lakes in regions A, C and D respectively. However, based on modern glacier mass balance observation data, we estimated that glacial meltwater may have contributed 22.2%, 39.8%, 50.6% and 100% to the increasing water storage during the period 2000–2013 by rough estimates in regions A, B, C and D, respectively, indicating that glacial meltwater perhaps was a primary contributor to lake expansion in region D, which was located in an extremely cold and dry climate with a broad distribution of glaciers.

A novel systematic heterostructures based on NiO/ZnSnO3 microsphere-decorated fibers were produced with a simple two-step process based on the electrospinning and hydrothermal procedures. A large density of NiO microspheres were homogeneously and epitaxially decorated on ZnSnO3 nanofibers. The crystal, structural and surface compositional properties of sample based on NiO/ZnSnO3 composites were investigated by XRD, SEM, TEM, EDX, XPS and BET characterization. The complex heterostructure based on NiO/ZnSnO3 microsphere-decorated fibers had shown an extremely huge specific surface area with mesoporous nature, which is essential for superior gas sensors. The as-produced sensors based on NiO/ZnSnO3 composites display superficially improved sensing characteristics, including high sensitivity and selectivity response with fast response and recovery speed towards ethanol gas at low operational temperature as compare to pure ZnSnO3 nanofibers. The sensitivity response of sensor based on NiO/ZnSnO3 microsphere-decorated fibers were 23.95 towards 20 ppm ethanol gas at 160 °C, which was about 2.5 times superior than that of bare ZnSnO3 nanofibers. The upgraded sensitivity performance of composites based on NiO/ZnSnO3 microsphere-decorated fibers might be ascribed to the large specific surface area with mesoporous nature having enormous quantity of oxygen contents, p-n heterojunction effects and synergetic actions between NiO and ZnSnO3 heterostructure.

Reconstructing vegetation and climate changes after the Last Glacial Maximum on the Tibetan Plateau (TP) is a key to understand past Indian Summer Monsoon (ISM) dynamics and the interplay between the ISM and Westerlies. In this study, a pollen record covering the last deglaciation and Holocene from Lake Tangra Yumco on the central TP is presented. A regional vegetation and climate history on the TP during the late glacial period is inferred, corresponding to long-term variations in the atmospheric circulation systems. Prior to 16,100 cal a BP, most areas of the TP are covered by treeless vegetation, mostly affected by the Westerlies. After that three major vegetation shifts to more humid-preferring vegetation types on the TP are detected during 16,100–14,600, 13,600–13,000, 12,400–10,400 cal a BP. These shifts should indicate three rapid intensifications in the ISM. During the Holocene (11400–3000 cal a BP), alpine steppe persists in the Tangra Yumco basin. Moistest conditions with strongest ISM occur prior to 8600 cal a BP. After 8600 cal a BP, climate is probably drier with a weakened ISM. Moreover, drought events at 9600–9300, 8200–7400, 5500, 4700–3700, 3200 cal a BP indicate the weakening events of ISM. Vegetation and climate changes on the central TP are mainly insolation driven, but are also associated with the influence of Holocene abrupt cold events in the North Atlantic region.

The development of efficient adsorbents is significant for the miniaturization and cost reduction of water purifying facility. In our previous study, a new kind of silica aerogel fibers (SAFs) with hierarchical structure and hollow structure were developed, which shows outstanding mass transport property and adsorption performance. Herein, we further control and study the hierarchical structure and hollow structure of silica aerogel fibers by changing the sulfuric acid concentration of ageing bath and spinning speed. For removing methylene blue, A0W120 SAFs sample, with DI water as ageing bath and a winding speed of 120 mm/s, presents the best mass transport property and adsorption performance, as they possess larger pore sizes in the outer layer, thinner fiber wall and higher degree of hollowness. The removal rates of methylene blue by A0W120 SAFs sample is up to 91.6% and 98.2% in 2 and 5 min, respectively, which are at least 30% higher than other comparable commercial adsorbents, while the adsorption capacity of methylene blue reaches up to 139.1 mg/g.

Selin Co, the largest lake situated on the central Tibetan Plateau (TP) and lying in the transitional zone between the Indian Summer Monsoon and the Westerlies, is an ideal site to investigate the region's paleoclimatic evolution since the Late Pleistocene. In this study, we present a high-resolution geochemical and mineralogical record retrieved from a 585-cm core in Selin Co covering the last 13 cal kyr BP based on a robust AMS 14C-determined chronology with a reservoir effect calibration. Various proxies, such as the mean grain size, Ti, Ca, Rb/Sr, total inorganic carbon (TIC) and total organic carbon (TOC), showed that the period from 12.9 to 11 cal kyr BP was characterized by stronger runoff, lower salinity and a higher lake level, indicating a cold and wet period. A Younger Dryas event likely occurred during the period 12.8–12.5 cal kyr BP, and all proxies exhibited a sharp change from 11.2 to 10.8 cal kyr BP that showed the termination of the cold/wet period followed by the onset of the Holocene. From 11 to 8 cal kyr BP, a transition from a drier to a relatively wet period occurred. An abrupt decrease in the TOC record in Selin Co at ~9.2 cal kyr BP suggested a cold event. During the period 8 to 4 cal kyr BP, a relatively warm and dry climate was observed. At ~4 cal kyr BP, all proxies indicated a low lake level and hence a dry event in Selin Co. A stable low lake level after 4 cal kyr BP was observed until an increase beginning at 800 cal yr BP. A significant lake level rise has coincided with the strengthening Westerlies during recent decades. These climatic variabilities in the Selin Co area since the Late Glacial have primarily been driven by temperature-induced evaporation in addition to precipitation via monsoonal circulation and/or westerly jets.

In this work, g-C3N4@TiO2 nanostructures with hollow sphere morphology, small grain size, high crystalline quality, and high surface area are successfully synthesized by the annealing method using melamine and hollowsphere precursor, which could be a universal method to synthesis hollow sphere nanoheterojunction. Excellent photocatalytic property was observed from the as-prepared g-C3N4@TiO2 nanostructure with 466.43 μmol·g–1·h–1 hydrogen generation rate under visible light irradiation (>420 nm), which was 5.5 times as much as the control couple, nanoparticle nanoheterojunction g-C3N4@TiO2. No apparent deactivation was found during the follow-up cycle performance test. The special morphology and the heterojunction construction contribute to both visible light absorption and photogenerated electron–hole pair separation efficiency and finally to the photocatalytic property. The content of g-C3N4 was proved to be an important parameter for the promotion of the photocatalytic property. Overlarge content may l...

A novel ratiometric electrochemiluminescence (ECL)-electrochemical (EC) hybrid biosensor with a high accuracy and reproducibility was fabricated for the ultrasensitive detection of miRNA-133a. With the help of a DNA tetrahedron nanostructure and hybridization chain reaction dual amplification strategy, the detection limit of 12.17 aM for miRNA-133a was obtained.

Vascular endothelial growth factors (VEGFs) play an important role in tissue repair and regeneration. In this study, VEGFs were immobilised by photo-reactive gelatine by photo-irradiation and the effect of immobilisation was quantitatively investigated. Immobilised VEGFs enhanced endothelial cell migration and growth more than soluble VEGFs. In addition, the activation effects depended on the VEGF isoforms. Prolonged activation of phosphorylation sites in the VEGF receptor, which is associated with migration and proliferation, was observed on the immobilised VEGF surfaces. The results indicated that photo-immobilised VEGFs induced high cell activation by stimulating phosphorylation of the VEGF receptor, VEGFR2, which activated multiple cell functions.

Herein, we have presented a facile and efficient method of ring-opening nucleophilic fluorination of aziridines, affording highly regio-selective β-fluorinated amines. Firstly, the example of ring-opening hydrofluorination of azetidines was reported. Then, the Olah's reagent also provided a promising method for the construction of enantioenriched β-fluoro-α-amino acid derivatives, which could be used for the preparation of peptide-based bioactive molecules.

In this study, a wavelength-resolved electrochemiluminescence resonance energy transfer (ECL-RET) ratiometric immunosensor from Au nanoparticle functionalized graphite-like carbon nitride nanosheets (Au-g-C3N4) to Au nanoclusters (Au NCs) has been constructed for the first time. At a working voltage of 0 to -1.2 V, Au-g-C3N4 showed a strong cathodic ECL emission with a peak at 460 nm, which overlapped well with the absorption spectra of Au NCs thus stimulating the fluorescence emission of Au NCs at 610 nm. Moreover, within this voltage range, the Au NCs showed no ECL signal; therefore, they would not interfere with the detection of the system. We used cardiac troponin I (cTnI) as an analytical model to construct a sandwich immunosensor based on the ECL-RET ratiometric strategy. By measuring the responses of the ECL460 nm/FL610 nm ratio at different cTnI concentrations, the sensitive detection of cTnI with a wide range of 50 fg mL-1 to 50 ng mL-1 and a low detection limit of 9.73 fg mL-1 can be achieved. This work enriches the wavelength-resolved ECL-RET system and provides an innovative reference for the development of more efficient and sensitive ECL-RET ratiometry.

A highly enantioselective [3 + 2] cycloaddition between 2,3-dioxopyrrolidines and N-2,2,2-trifluoroethylisatin ketimines with a quinine-derived squaramide catalyst in a diastereodivergence way has been described, which leads to two diastereomeric enantioenriched bispiro[oxindole-bi-pyrrolidine]s (incorporating CF3 units) with four consecutive stereocenters, including two adjacent spiro-quaternary centers. The reaction afforded the corresponding adducts in good to excellent yields with good to excellent enantioselectivities.

Ratiometric electrochemiluminescence (ECL) has attracted special focus in the biological analysis field, because it could eliminate the environmental interference and allow for precise measurement. Herein, a dual-wavelength ratiometric ECL biosensor was designed for the detection of cardiac troponin I (cTnI), where (4,4′-dicarboxylic acid-2,2′-bipyridyl) ruthenium(II) (Ru(dcbpy)32+) and Au nanoparticle-loaded graphene oxide/polyethylenimine (GPRu–Au) nanomaterial acts as an acceptor, and Au nanoparticle-modified graphitic phase carbon nitride nanosheet composite (Au–CNN) acts as donor. Au–CNN shows a high and steady ECL signal centered at 455 nm, which is well-matched with the adsorption of GPRu–Au; thereby, a highly efficient electrochemiluminescent resonance energy transfer (ECL-RET) sensing platform is designed. AuNPs facilitate the immobilization of antibody on the nanomaterials through a Au–N bond. The high surface area of graphene oxide/polyethylenimine allows a large number of Ru(dcbpy)32+ to be lo...

The fabrication of piezoresistive strain sensor with unified and balanced properties of high sensitivity, stretchability, and durability still remains a great challenge due to the oversimplified thin film structure of strain sensor. In this work, a high-performance strain sensor based on conductive poly(styrene-butadiene-styrene)/carbon nanotube fiber (SBS/CNT fiber, SCF) was prepared via wet-spinning. Then, the morphology, mechanical property, piezoresistive performance and sensing mechanism of the SCF-based sensors were systematically investigated. The resultant SCF-based sensors simultaneously demonstrated superior sensitivity (with a gauge factor of 175 under 50% deformation), wide workable range (>260%) and excellent durability due to the excellent flexibility of SBS polymer (the breaking elongation of pure SBS fiber > 1300%), high conductivity of CNT (105 S/cm) and the strong π-π interaction between CNT and SBS. These properties make the composite fiber a perfect fit to monitor various large deformation in a wide range of applications. Moreover, the associated sensing mechanism was also systematically explained by tunneling theory and the evolution of the conductive network during the stretching-releasing process.

Graphene-based hydrogel materials have attracted increasing attention in engineering applications such as oil-water separation. In this work, we report a novel, facile, environmental-friendly and cost-effective synthesis method for fluorographene nanosheets through Michael’s Addition reaction and the fabrication of amphiphobic LA/F/rGO hydrogel, based on a low-temperature hydrothermal process of partially reduced graphene oxide (rGO) and 1H,1H,2H,2H-perfluorodecanethiol (PF) in the presence of a reducing agent l -ascorbic acid (LA). The LA/F/rGO hydrogel has a low density of ∼19 mg/ml, with excellent thermal stability and regenerable adsorption capacity (up to 20 times its original weight) for various organic solvents. The as-prepared LA/F/rGO hydrogel shows intriguing oil repellant and oil bouncing behaviors underwater. Pre-soaking with water or oil allows selective and efficient separation of water or oil from their mixtures. The new LA/F/rGO hydrogel developed in this work has been demonstrated as a promising candidate for efficient adsorbent of oil pollutants in waste water treatment, oil/water separator and oil fence material. This work provides new insights into the development of novel graphene-based nanocomposite materials for oil-water separation and oil leaking, with a wide range of engineering and environmental applications.

The tailored nanofilms have attracted a rapidly growing interest in various separation processes. Recently, microporous materials have provided a promising way to meet this requirement due to their distinct structures. However, suffering from the uncontrollable heterogeneous nucleation, crystalline materials are difficult to form the ultrathin and defect-free nanofilms. Herein, tannic acid (TA)/Fe3+ complex, which was microporous amorphous material, was fabricated on the ultrafiltration membrane via the layer-by-layer technique. Interestingly, in addition to the pH value mentioned in the literature, the aggregation of Fe3+ in the aqueous solution was also found to have significant influence on chemical composition and physical structure of the complex. Through the strict control on the Fe3+ aggregation, the defect-free TA/Fe3+ nanofilm has an average pore size of 0.7 nm, which was the smallest among the reported TA/Fe3+ nanofilms. More importantly, the pore size of nanofilm was in accordance with our expectation, and the molecular dynamic simulation further confirmed the result. It demonstrated that the tailored pore structure of the nanofilm can be designed on the basis of the molecular structure. Moreover, the nanofilm has an ultrathin thickness of 5 nm. To the best of our knowledge, the nanofilm was the thinnest nanofilm used for liquid separation. Compared with the nanofilms made by various materials, the TA/Fe3+ nanofilm obviously broke through the selectivity-permeability trade-off of the nanofilms, with the ultrathin thickness and the narrow pore size distribution. Additionally, the TA/Fe3+ nanofilm can precisely separate molecules that were close in size. This work provides a facile method to fabricate tailored nanofilms with high performance designed at a molecular level.

Artificial materials have no biological functions, but they are important for medical devices such as artificial organs and matrices for regenerative medicine. In this study, mitogenic and differentiation‐inducible materials are devised via the simple coating of polypeptides, which contain the sequence of epidermal growth factor or insulin‐like growth factor with a key amino acid (3,4‐dihydroxyphenylalanine) of underwater adhesive proteins. The adhesive polypeptides prepared via solid‐phase synthesis form layers on various substrates involving organic and inorganic materials to provide biological surfaces. Through the direct activation of cognate receptors on interactive surfaces, the materials enable increased cell growth and differentiation compared to that achieved by soluble growth factors. This superior growth and differentiation are attributed to the long‐lasting signal transduction (triggered by the bound growth factors), which do not cause receptor internalization and subsequent downregulation., 3,4‐dihydroxyphenylalanine‐containing peptides form bioactive layers on organic and inorganic material surfaces. On the adhesive growth factor nanolayers, cells receive long‐term biological signals from immobilized growth factors, leading to improved cell growth and differentiation.

Water resources are rich on the Tibetan Plateau, with large amounts of glaciers, lakes, and permafrost. Terrestrial water storage (TWS) on the Tibetan Plateau has experienced a significant change in recent decades. However, there is a lack of research about the spatial difference between TWSC and lake water storage change (LWSC), which is helpful to understand the response of water storage to climate change. In this study, we estimate the change in TWS, lake water storage (LWS), soil moisture, and permafrost, respectively, according to satellite and model data during 2005−2013 in the inner Tibetan Plateau and glacial meltwater from previous literature. The results indicate a sizeable spatial difference between TWSC and LWSC. LWSC was mainly concentrated in the northeastern part (18.71 ± 1.35 Gt, 37.7% of the total) and southeastern part (22.68 ± 1.63 Gt, 45.6% of the total), but the increased TWS was mainly in the northeastern region (region B, 18.96 ± 1.26 Gt, 57%). Based on mass balance, LWSC was the primary cause of TWSC for the entire inner Tibetan Plateau. However, the TWS of the southeastern part increased by 3.97 ± 2.5 Gt, but LWS had increased by 22.68 ± 1.63 Gt, and groundwater had lost 16.91 ± 7.26 Gt. The increased TWS in the northeastern region was equivalent to the increased LWS, and groundwater had increased by 4.47 ± 4.87 Gt. Still, LWS only increased by 2.89 ± 0.21 Gt in the central part, and the increase in groundwater was the primary cause of TWSC. These results suggest that the primary cause of increased TWS shows a sizeable spatial difference. According to the water balance, an increase in precipitation was the primary cause of lake expansion for the entire inner Tibetan Plateau, which contributed 73% (36.28 Gt) to lake expansion (49.69 ± 3.58 Gt), and both glacial meltwater and permafrost degradation was 13.5%.

Two-dimensional (2D) nanomaterial-nucleic acid interactions have been widely used in the construction of fluorescent sensors, but they are rarely used in the construction of electrochemiluminescent (ECL) sensors and have never been used in the design of ratiometric ECL sensors. Therefore, a ratiometric ECL sensing platform was developed in this study based on the ECL resonance energy transfer (ECL-RET) of graphitic carbon nitride nanosheets (GCNNs)/Ru(bpy)32+ donor/acceptor pair. The 2D GCNNs showed much weaker affinity to the long dsDNA duplexes formed by hybridization chain reaction (HCR) than Ru(bpy)32+-lableled fuel hairpin DNAs (H1 and H2) for HCR. Therefore, the target-initiated HCR resulted in the luminescence enhancement of the GCNNs at 460 nm and the luminescence attenuation of the Ru(bpy)32+ at 610 nm. By measuring the I460 nm/I610 nm ratios, quantitative analysis of microRNA-133a was realized with a limit of detection of 0.41 pM. In addition, this ECL-RET sensing platform can be easily extended to detect metal ions or aptamer substrates by simply redesigning helper DNAs without changing the sequences of fuel hairpin DNAs. Moreover, due to the programmability of HCR, a series of sensitive logic gates (“OR”, “INHIBIT”, “AND”, “NAND” and “INHIBIT-OR”) based on the ECL-RET ratiometry can be constructed and responded to as low as 100 pM of Hg2+ or Ag+.

Lake water storage is essential information for lake research. Previous studies usually used bathymetric data to acquire underwater topography by interpolation method, and to therefore estimate water storage. However, due to the large area of Tibetan Plateau (TP) lakes, the method of bathymetry was challenging to cover the whole region of one lake, and the accuracy of the underwater topography, in which no bathymetric data covered, was low, which resulted in a comparatively large error of lake water storage estimation and its change. In this study, we used Shuttle Radar Topography Mission (SRTM) and in situ bathymetric data to establish the underwater topography of Hohxil Lake (HL) and Lexiewudan Lake (LL) in the Hohxil Region of North TP and estimate and analyzed the changes of lake level and water storage. The results showed HL and LL’s water storage was 5.12 km3 and 5.31 km3 in 2019, respectively, and their level increased by 0.5 m/y and 0.57 m/y during 2003−2018, respectively. They were consistent with those (0.5 m/y and 0.5 m/y) from altimetry data, and they were much more accurate than those results (0.077 m/y and 0.156 m/y) from bathymetric data. These findings indicated that this method could improve the accuracy of lake water storage and change estimation. We estimated water storage of two lakes by combining with multitemporal Landsat images, which had doubled since 1976. Our results suggested that the increasing precipitation may dominate the lake expansion by comparing with the change of temperature and precipitation and the increasing glacial meltwater contributed approximately 4.8% and 10.7% to lake expansion of HL and LL during 2000–2019 based on the glacier mass balance data, respectively.