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Urbanization, an unavoidable global process, has driven land use change, impacted ecosystem services, and induced serious environmental problems. As a result, urban planning is a critical issue in sustainable development. In this study, we developed a framework to quantify how urbanization influences ecosystem services (ESs) in order to provide suggestions for urban planning during large scale urban agglomeration in northwestern China. We separated the region into three sub-regions (developed urban, developing urban, and rural areas), quantified five critical ESs (crop production, carbon storage, nutrient retention, sand fixation, and habitat quality), analyzed the relationships (trade-off, synergy, and bundle) among ES changes, and investigated the impacts of urbanization on these ESs. The results show that urbanization results in large scale reclamation and small scale deforestation in rural areas; it comprehensively results in an increase of four ESs (not habitat quality). Urban expansion mainly occurs in developing urban areas and causes a decrease in four ESs (not sand fixation). Based on temporal change in ESs, synergy relationships exist among them, except for between nutrient retention and crop production, which have an insignificant correlation. Urban expansion would strengthen the synergy relationships among regulating services, while green infrastructure in core urban areas would weaken these relationships. Based on the spatial distribution of ES change, two bundles were identified among the five ESs: 1) crop production, carbon storage, and nutrient retention; and 2) sand fixation and habitat quality. Based on these findings, several suggestions for urban expansion and land use planning are proposed to achieve an optimized balance between urbanization and ES protection. Investigating the impacts of rapid urbanization on ESs and their relationships could provide scientifically based suggestions for urban planning according to ES protection, sustainable urban development, and human well-being. [ABSTRACT FROM AUTHOR]

In order to study the generation of organic acids and their dissolution effects on reservoirs, the type, yield and stability of common organic acids in the stratum were analyzed by laboratory simulations of the organic acid generation from kerogen and the decarboxylation of these organic acids. A kinetic model for the generation of organic acids and thermodynamic models of the decarboxylation of organic acids and the dissolution reaction were established. Acetic acid was used as an example to characterize the integration of the organic acid generation, decarboxylation, and dissolution under geological conditions. In addition, the process of dissolution pore development in shale reservoirs of various ages was reproduced. The results show that among the organic acids produced in the kerogen thermal simulation, the most stable is acetic acid with a decarboxylation temperature higher than 250 °C, followed by formic acid, and oxalic acid is the least stable. A large amount of organic acids can be produced in the middle thermal maturation stage (Ro = 0.89%–1.25%) of organic matter (OM). The modeling method combining kinetics and thermodynamics can achieve the quantitative characterization of the process of dissolution pore development. According to the calculation results, if the organic acids dissolve the reservoir as a whole, the porosity increment produced by the dissolution of the reservoir’s minerals is not significant. In other words, the dissolution of the reservoir by organic acids does not have an overall significance. However, if the organic acids only move along the predominant pathway (such as fractures) after their generation and dissolved the surrounding minerals of this channel, obvious dissolution can be produced. Comparison of the mineral composition and crack development of shale reservoirs indicates that organic acids could preferentially dissolve the reservoir cracks, so as to improve the porosity and permeability of the reservoir. [ABSTRACT FROM AUTHOR]

In this study, 32 experimental measurements on the isothermal adsorption of methane for 18 shale samples from China's three largest continental oil basins—Songliao, Bohai Bay, and Ordos basins—were used to construct comprehensive polynomial simulation and prediction models for Langmuir volume and Langmuir pressure. The models were based on shale properties (total organic carbon (TOC) content, amount of residual hydrocarbon S 1 , and mineral composition of rocks) and adsorption condition (temperature) using a weighted sum of multiple variables. The influences of various factors were quantitatively characterized, and the prediction accuracy was verified. Langmuir volume is mainly affected by temperature, shale TOC content, amount of residual hydrocarbon, and clay mineral content; Langmuir pressure is mainly affected by clay, carbonate, feldspar and illite content (because shale pore size can be affected by shale mineral composition). Based on the resource potential and the producibility of shale gas, the area suitable for shale gas exploration and development should have high abundance of organic matter (TOC and residual hydrocarbon S 1 ), low clay mineral content and feldspar content, high conversion rate of montmorillonite to illite (strong diagenesis), and high carbonate content. The comprehensive polynomial prediction model can effectively simulate and predict Langmuir volume and Langmuir pressure, thereby reducing the amount of work necessary for evaluation of shale gas resource potential and economic feasibility. [ABSTRACT FROM AUTHOR]

There remains no detailed record of the Middle Miocene vegetation and climatic changes which occurred in central Asia and their possible driving mechanisms. This is because there is still a lack of high resolution records. Here, we present a sporopollen record from the Wushan Basin on the northeastern Tibetan Plateau, central Asia, spanning the period ∼16.1–13.6 Ma. The sporopollen record shows that a dense mixed forest growing in rather warm and humid climatic conditions was affected by a general drying trend during the period ∼16.1–15 Ma. It demonstrates that although the climate was generally warm and humid during the Middle Miocene Climate Optimum (MMCO), it was also a time of climatic instability. The dense forest gave way to an open forest in response to a less humid climate between ∼15 and 14.4 Ma. Dense mixed forest made a return with an increasingly humid climate during ∼14.4–13.8 Ma. This vegetation and climatic succession could be associated with global cooling, or more particularly, a higher temperature rebound set against the background of a long-term cooling trend. A more open forest appearing in response to drier and colder climatic conditions dominated the study area during the ∼13.8–13.6 Ma period. This could be compared to the rapid global cooling event Mi-3b. This significant global cooling event exerted a major impact on terrestrial vegetation, climate and biota. Our high resolution sporopollen record demonstrates that global climate changes could have been the first order driving force for the Middle Miocene vegetation and climate changes seen in the Wushan Basin in central continental Asia, with the tectonic uplift of the Tibetan Plateau probably playing a subordinate role. [ABSTRACT FROM AUTHOR]

The loess-paleosol sequences of the Chinese Loess Plateau (CLP) are major paleoclimatic archives which document the evolution of the East Asian Monsoon (EAM) and changes in the Northern Hemisphere ice sheets during the Quaternary glacial-interglacial cycles. However, the mechanisms regulating the trend of EAM variations on a tectonic scale are unclear. The loess deposits of the western CLP, which have a close relationship with tectonics and climate, are much better-suited to exploring these mechanisms than those of the central CLP. However, studies of long-term EAM evolution from the western CLP have been hindered by the lack of long, accurately-dated sequences with high sediment accumulation rates. Here, we address this problem via high resolution magnetostratigraphic, magnetic susceptibility and grain-size analyses of a 416.2 m-long drill core located at Xijin Village, near Lanzhou. Paleomagnetic dating indicates that the basal age of the Xijin loess is ∼2.2 Ma. The χ and grain-size records reveal that the East Asian Summer Monsoon (EASM) and East Asian Winter Monsoon (EAWM) strengthened synchronously at ∼1.24 Ma. Subsequently, during interglacial periods, the EASM began to penetrate, and then dominate, in the Lanzhou region. This was followed by two stepwise uptrends, commencing at ∼0.87 and ∼0.62 Ma, which resulted in an increasingly moist interglacial climate in the region. We suggest that the uplift of the Tibetan Plateau was largely responsible for these three stepwise enhancements of the EASM. Overall, however, the long-term trend of strengthening in EAWM in the area may have been primarily caused by long-term global cooling from the Late Pliocene onwards. [ABSTRACT FROM AUTHOR]

The long-term paleoclimate record in Asia and its comparison with the global climate record are of vital importance to understanding the coupling mechanisms between tectonics and climate. However, such long-term climate history in Asia revealed using the biomarker perspective has remained elusive. Here, we reconstruct the Neogene–Quaternary climatic history of the Northeastern (NE) Tibetan Plateau based on the integrated biomarker records of the Tianshui Basin and multiple published data from its surrounding localities. These comprehensive results indicate that the NE Tibetan Plateau did not have a consistent aridity trend until ∼4 Ma. Before 4 Ma, the Neogene climate was generally humid although this pattern was temporarily interrupted by two drying intervals at ∼14.5–∼12.5 and ∼10–∼6 Ma. Each of the two drying intervals and the permanent aridification trend roughly correspond to one phase of global cooling and/or uplift event of the Tibetan Plateau, highlighting the importance and complexity of tectonic–climate interactions. However, our study indicates increasing influence of tectonic uplift on the NE Tibetan Plateau climate since late Pliocene. [ABSTRACT FROM AUTHOR]

Massive deposits of limestone were encountered for the first time by wells drilled into the bedrocks of Yitong Basin, Northeast China. U–Pb zircon dating analyses with LA-ICP-MS were then employed to determine the geological ages of the deposits and analyze the impact of a later magmatic intrusion upon the hydrocarbon generation and preservation environment in the deposits. Analyses of 6 granite samples taking from the limestone shows that the basement of the Yitong Basin contains numerous zircons of magmatic origin and these zircons are characterized in CL images as light color, clear oscillatory zoning and intact crystalline form, In terms of REE (rare earth elements) content and its distributive pattern, the zircons are shown with mild loss of Eu, high Th/U ratio and left-slanting distributive curves. Concordia plots based on U–Pb dating of 61 zircons of magmatic origin showed concentrated data points along the Concordia line, indicating no obvious Pb loss. The crystallization ages of 6 granite samples were dated as 220 Ma, 192 Ma, 261 Ma, 185 Ma, 270 Ma and 273 Ma, respectively. Based on the understanding, we inferred that the limestone of sedimentary genesis imbedded with the Permian formations of the basin was formed during deposition in the Permian era. The magma activity was the most active during the Jurassic. Magmatic intrusion was thought to be originated from deeper parent rocks below the Permian layers. It cut through the Permian limestone from the bottom up and released great amount of heat to bake the limestone. This accelerated hydrocarbon generation in the limestone and increased its KTG (kerogen to gas) rate to 0.9 or more during 190 Ma and 185 Ma. Early hydrocarbon generation and poor preservation are the two hydrocarbon-related features of the limestone. In terms of reservoir lithology, the limestone went through thermal contact metamorphism with the heat and volatile components from magmatic activities. It is also observed that contact metamorphism of the limestone was the most active near the eruption points of magma. [ABSTRACT FROM AUTHOR]

This article performed a series of parallel experiments with numerical modeling to reveal key factors affecting the gas adsorption capacity of shale, including shale quality, gas composition and geological conditions. Adsorption experiments for shales with similar OM types and maturities indicate that the OM is the core carrier for natural gas in shale, while the clay mineral has limited effect. The N 2 and CO 2 adsorption results indicate pores less than 3 nm in diameter are the major contributors to the specific surface area for shale, accounting for 80% of the total. In addition, micropores less than 2 nm in diameter are generated in large numbers during the thermal evolution of organic matter, which substantially increases the specific surface area and adsorption capacity. Competitive adsorption experiments prove that shale absorbs more CO 2 than CH 4 , which implies that injection CO 2 could enhance the CH 4 recovery, and further research into N 2 adsorption competitiveness is needed. The Langmuir model simulations indicate the shale gas adsorption occurs via monolayers. Geologically applying the adsorption potential model indicates that the adsorption capacity of shale initially increases before decreasing with increasing depth due to the combined temperature and pressure, which differs from the changing storage capacity pattern for free gases that gradually increase with increasing depth at a constant porosity. These two tendencies cause a mutual conversion between absorbed and free gas that favors shale gas preservation. During the thermal evolution of organic matter, hydrophilic NSO functional groups gradually degrade, reduce the shale humidity and increase the gas adsorption capacity. The shale quality, gas composition and geological conditions all affect the adsorption capacity. Of these factors, the clay minerals and humidity are less important and easily overshadowed by the other factors, such as organic matter abundance. [ABSTRACT FROM AUTHOR]

Abstract: Long and continuous terrestrial paleoclimate records are important in understanding forcing mechanisms of Cenozoic climate. However, such records are rare. Sediments in basins near the edges of the Tibetan Plateau are potential paleoclimate archives, but dating them is a challenge. Here we report a successful application of paleomagnetism to a set of fluvio-lacustrine sediments in the Tianshui Basin, NE Tibet, and found that this set of sediments spans ∼17.1–6.1Ma. Preliminary biomarker studies found that this set of sediments has climatically important organic components and, thus, these sediments are perfect paleoclimatic archives. Generating high-resolution biomarker records will be able to cast light on climatic history in NE Tibet during the Miocene. [Copyright &y& Elsevier]

Abstract: The Miocene vegetation and climate history of western China remains unclear. However, widely-distributed Miocene sediments of the Tianshui Basin in the NE Tibetan Plateau provide a great potential for deciphering the Miocene vegetation and climate history of this region. This paper presents first sporopollen record from these sediments, covering the period from 17.1 to 6.1Ma. Sporopollen data reveal that temperate, warm-temperate broad-leaved forest of Quercus, Ulmus and Betula dominated the Tianshui region between 17.1 and 14.7Ma, which was replaced by forest or forest-steppe of Ulmus, Artemisia and Betula between 14.7 and 11.7Ma. After a return to a broad-leaved forest of Betula and Quercus during 11.7–8.5Ma, the forest decreased rapidly and was replaced mostly by steppe vegetation (mainly composed of Artemisia, Chenopodiaceae and Poaceae) after 8.5Ma. We interpret the observed vegetation changes as a result of global climate change, which is characterized by global cooling, development of Arctic ice-sheets and permanent El Niño state after the Middle Miocene Climatic Optimum. The rapid development of steppe at about 8.5Ma suggested a permanent drying of the Asian interior at this time, coinciding with the onset of the well-known Hipparion red clay deposition in North China. [Copyright &y& Elsevier]

Abstract: Based on the density functional theory (DFT), using first-principles plane-wave ultrasoft pseudopotential method, the models of the unit cell of pure ZnO and two highly Li–2N co-doped supercells of Zn0.9375Li0.0625O0.875N0.125 and Zn0.9167Li0.0833O0.8333N0.1667 were constructed, and the geometry optimization for the three models was carried out. The total density of states (TDOS) and the band structures (BS) were also calculated. The calculation results showed that in the range of high doping concentration, when the co-doping concentration is more than a certain value, the conductivity decreased with the increase of co-doping concentration of Li–2N in ZnO, which agrees with the change trend of the experimental results. [Copyright &y& Elsevier]

The Qilian Shan, on the Northeast margin of the Qinghai–Tibetan Plateau, is weakly influenced by the Asian monsoon. Until recently, the Quaternary glacial geology of this region has been poorly understood. This paper describes a sequence of Quaternary glacial deposits in the upper reaches of the Bailang River. Using electron spin resonance (ESR), thermoluminescence (TL) and radiocarbon dating, tills, loess, buried soils and landforms were dated. The oldest till was dated ∼463 ka BP by ESR. A younger till and its outwash terrace were dated to ∼135 and 130 ka BP. The loess on this outwash terrace was dated to 141.7±11.4 ka BP at its base and 43.7±3.5 ka BP in its central part by TL dating. A buried soil on a younger till was dated at 6920±78 ka BP using 14C. The glacial landforms and these dating results show that glacial advances occurred during the Little Ice Age, the Neoglacial, MIS 2–4, MIS 6, and MIS 12. Glaciation during MIS 12 implies that the Qilian Mountains were rising coevally with the Qinghai–Tibetan Plateau, and were probably at a sufficient elevation for glaciation since at least 463 ka BP. [Copyright &y& Elsevier]

The transfer of Cd and Zn from calcareous soils nearby a non-ferrous mining and smelting bases to the spring wheat (Triticum aestivum L.) and corn (Zea mays L.) tissues and the interactions between the two metals concerned were investigated under actual field conditions. Samples of soils and entire crops were randomly collected during harvest time in 1998 in the Baiyin region. The soil metal contents showed that the furrows had been polluted (mean values: 3.16 mg kg−1 for Cd; 146.78 mg kg−1 for Zn) and the significant spatial variation of the soil contamination existed here (ranges, Cd: 0.14–19.3 mg kg−1; Zn: 43.5–565.0 mg kg−1). The translocation ratios of the two metals from soil to crop parts in the region studied were relatively lower and the order of the element transfer in different plant tissues was root>stem>grain. The transfer ratio of element Cd was lower than that of element Zn. Cd and Zn uptake by the crop structures could be best described by four models (P<0.01): linear; exponential; quadratic; and cubic. Apart from a linear relationship between the element Cd in the corn grains and soils, models were generally non-linear. An analysis of Cd&z.sbnd;Zn interaction mechanism led to the conclusion that the effects of the two metals were synergistic to each other under field conditions, in which increasing Cd and Zn contents in soils could increase the accumulations of Zn or Cd in the two crops. [Copyright &y& Elsevier]

• Spatial relationships among five ecosystem services were quantified. • Random forest analysis was used to identify their socio-ecological drivers. • Topography plays an increasing role in sand fixation during 1989–2017. • Socioeconomic development alters ecosystem service relationships. • Land use pattern and vegetation coverage are critical in policy making. Understanding the dynamics and relationships among ecosystem services (ESs) and their underlying socio-ecological driving mechanisms has great importance for policy-makers to achieve sustainable development. In this study, using the City Belt along the Yellow River in Ningxia, China as the study area, we quantified and mapped five ESs for the period 1989–2017, analyzed the spatial relationships among ESs through hotspots analysis, correlation analysis and cluster delineation, and explored the dynamic impacts of socio-ecological factors on ESs through random forest analysis. The results showed that spatial distributions and relationships among ESs had significant change over the past three decades, driven by the varied impacts of socio-ecological factors. Cropland in the central plain could supply higher values of food production, carbon sequestration and nutrient retention, which were mainly impacted by land use pattern and vegetation coverage and existed significant synergies among them at regional scale. Specially, the hotspots of food production and carbon sequestration both decreased in the northern part over time, while the former one was caused by the increasing impacts of socioeconomic indicators and the latter one by climate factors. Northwestern and southern mountains could provide higher values of sand fixation, which was mainly impacted by the increasing impact of topography and decreasing impact of climate factors. Thus hotspots of sand fixation increased in the mountainous areas and decreased in other regions. Socio-economic factors had an increasing impact on recreational opportunity, resulting the transformation of its hotspots from mountains to the central Yinchuan city and transition region between mountains and central plain. Dynamic impacts of socio-ecological factors could alter the spatial relationships among ESs and impact their co-occurrence across space. Specific management strategies have been proposed for different sub-regions to improve ESs under the land-use system reform, ecological civilization and rural revitalization in China. [ABSTRACT FROM AUTHOR]

• The strain field caused by nano-scale GP II zone in an Al -Zn- Mg-Cu alloy can be accurately measured by GPA technique. • The correctness of theoretical model of GP II zone can be verified by comparing it to the experimental strain field. • The level of residual strain along the x-direction is higher than along the y-direction. The Guinier-Preston (GP) II zone in an Al–Zn–Mg–Cu alloy was investigated by using a high-resolution electron microscopy (HREM). We used Geometric Phase Analysis (GPA) technique to measure the experimental HREM image and the simulated HREM image to obtain the strain distribution maps. The results show converging strain fields in the GP II zone, and the maximum compressive strain can reach −7.2% and −6.7%, respectively. The distribution of the experimental strain field was in consistence with that of the simulation result. The average strain of the alloy measured using XRD is 0.191%. [ABSTRACT FROM AUTHOR]

Abstract: This study presents new apatite fission-track (AFT) data from the Tianshui-Huicheng region, which is situated in the northeastern margin of the Tibetan Plateau. AFT results (including 19 detrital and 13 bedrock samples) show that deposition in the Tianshui-Huicheng basin range from early Eocene to late Miocene–Pliocene and most of the apatites derived from the Western Qinling orogenic belt, reflecting one rapid exhumation episode (at 34–29Ma) and two phases of volcanism (at 23–18Ma and ca. 13Ma). The exhumation history of the Tianshui-Huicheng region is likely related to episodic tectonic activity and directly linked to the kinematics of active deformation of the Tibetan Plateau. Active processes deciphered from the detritus indicate that deformation reached the northeastern Tibetan Plateau margin as early as ca. 49Ma, which is manifested by the initiation of the Tianshui-Huicheng basin. The 23–18Ma event, linked to the lithosphere deformation of the Western Qinling and the Neogene basin formation along the Tianshui-Huicheng region. By modeling the bedrock samples, an 8–4Ma event was revealed which resulted from the intense deformation of the Tianshui-Huicheng region. [Copyright &y& Elsevier]

A current-mode two-stage continuous-time pipelined (CTP) ADC for wideband receivers is proposed in this paper, to eliminate power-hungry front-end trans-impedance amplifier (TIA). An improved current mirror with low input impedance and high linearity is used to receive the current input signal and duplicate it to the delay chain and the quantization path of the 3-bit first stage. Then, the residue current is amplified and filtered by an embedded 1st-order TIA and further quantized by the second stage, which is implemented by a VCO-based quantizer to improve ADC energy efficiency and anti-aliasing filtering. Simulation results in a 12 nm FinFET process show that clocked at 4.8 GS/s, the proposed ADC achieves 55.7 dB SNDR for a 600 MHz bandwidth and consumes only 83.4 mW power under supplies of 0.9 V, 1.2 V, and 1.5 V, corresponding to an excellent FoM of 154.3 dB. [ABSTRACT FROM AUTHOR]

• Fano resonance based on MIM waveguide cavity with a metal nanowall is presented. • The geometric sizes, temperature effect on Fano resonance is analysis in details. • The proposed structure may have application in slow light, filter and sensor. The temperature control of Fano resonance via a resonator waveguide system which is composed of a side coupled ring cavity and a metal nanowall is presented. The ring resonator is filled with sealed ethanol which can tune the Fano resonance by the temperature. Two dimensional finite difference time domain method is used to calculate the transmission and field distribution. The Fano resonance is originated from the coupling between the discrete state and the continua state. The discrete state and continua state is from the side coupled ring resonator and the metal nanowall, respectively. The asymmetrical Fano linestyle can be tuned by changing the temperature of the sealed ethanol or the geometric parameters. Multiple Fano resonance can be obtained by introducing another ring resonator and can be tuned by temperature or size independently. The proposed plasmonic structure may have application in slow light device, nanoscale filter, all optical switch and refractive index sensor. [ABSTRACT FROM AUTHOR]

Optical switching based on metamaterial has attracted wide attention for its outstanding performance in light controlling and energy manipulation. Here, we present a theoretical investigation of tunable plasmonic absorption based on a plasmonic nanostructure with phase-changing material. The structure consists of double metal layers covered with nanoholes for perfect optical absorption. To make the optical absorption tunable, we design a G e 2 S b 2 T e 5 (GST) layer located between the double metal layers. Our design of the metamaterial structure can realize absorption switching through crystalline and amorphous phase transitions in near infrared range. Moreover, by tuning the different crystallization, the plasmonic absorption can be adjusted from 99.1% to 4.9%. The demonstration will pave the way towards the dynamical optical absorption control in both the nano-science field and a number of applications, including plasmonic switch, plasmonic modulator and plasmonic metasurfaces. [ABSTRACT FROM AUTHOR]

Understanding the spatial distributions of multiple ecosystem services (ESs), their associations, and their underlying socio-ecological contributing factors is critical for ES management. Using the city belt along the Yellow River in Ningxia, northwestern China, as a case study, this study quantified the spatial distribution of six ESs (food production, carbon sequestration, carbon storage, nutrient retention, sand fixation and recreational opportunity), analyzed the synergy and trade-off relations among them through correlation analysis, classified ES bundles through a self-organizing map method (SOM), explored the impacts of socio-ecological factors on the ESs through Ordinary Least Square regression (OLS) and Geo-detector analysis, delineated socio-ecological clusters using the SOM, and characterized the relationship between ES bundles and driver clusters through overlap analysis. The results suggest that spatial associations among ESs can be predicted by their driving mechanisms. Synergy relations existed among crop production, carbon sequestration, carbon storage and nutrient retention, and these were impacted by similar driving mechanisms. Synergy also existed between sand fixation and recreational opportunity, but significant differences existed in their driving mechanisms. Trade-off relations were shown between ESs in these two groups at the whole region scale. Three bundles were detected among the six ESs: bundle 1, characterized by recreational opportunity of high supply and other services of limited supply, was located in the transitional region between the central plain and the fringe mountains, and mainly driven by climate and proximity factors; bundle 2, characterized by high sand fixation, medium carbon storage and limited other services, was located in the northwestern and southern mountains and driven by climate and geography factors; bundle 3, characterized by high food production, carbon sequestration, carbon storage and nutrient retention of medium supply and other two services of limited supply, was located in the central plain and driven by vegetation coverage and proximity factors. Human activities can partly overcome the limitations of ecological conditions, thus specific strategies for different regions are proposed to maintain and improve ESs under global climate change. • Spatial correlations among six ecosystem services were assessed. • Their spatial co-variation were delineated and mapped using self-organizing map. • Their socio-ecological influencing background were detected. • Spatial associations among ecosystem services can be predicted by their driving mechanisms. [ABSTRACT FROM AUTHOR]

The electrical control of Fano resonance via a plasmonic waveguide system which is composed of a metal-air-metal stub coupled with ring cavity is presented. An organic material with a large electro-optical coefficient is incorporated in the stub to tune the Fano resonance by the external voltage. Two dimensional finite difference time domain method is used to calculate the transmission and field distribution. The Fano resonance is originated from the coupling between the stub and the ring resonator. The asymmetrical Fano linestyle can be tuned by changing the applied voltage or the geometrical parameters. The proposed plasmonic structure may have application in slow light device, nanoscale filter, all optical switch and refractive index sensor. [ABSTRACT FROM AUTHOR]

Abstract Spectral features and nanosensing of hexagonal array of holes with a circular cross section metamaterial are investigated by performing the three dimensional finite difference time domain simulation. Fabry-Perot resonance effect and localized surface plasmon resonance of the hexagonal holes array generate absorption peak under normal incidence. Besides the geometrical parameters of the nanostructure, absorption characteristics strongly depend on the refractive index of environmental or dielectric layer. The results of this paper may have potential application not only in plasmonic absorber but also in nanosensor. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The <2 μm fraction of Xijin loess includes both wind-blown detrital and in situ pedogenic components. • The pedogenic components are reversely correlated with the >40 μm fraction and global marine oxygen isotope. • The pedogenic components are superior to the magnetic susceptibility for high-resolution reconstruction of the Quaternary climate change in the western Chinese Loess Plateau. Abstract Chinese loess deposits preserve abundant information on the aridification of the Asian interior and Asian monsoon evolution during the Quaternary. Although substantial progress has been made in deciphering the paleoclimatic record of the thick loess deposits in the western Chinese Loess Plateau (CLP), the environmental significance of variations in the magnetic susceptibility (χ) and the ultrafine (<2 μm) grain-size is still unclear when compared with the central CLP. Here, we present high-resolution records of χ, frequency-dependent magnetic susceptibility (χ fd) and grain-size (<2 μm and >40 μm fractions) of the 416-m-long Xijin loess core from the Lanzhou Basin, northeastern Tibetan Plateau. Our results indicate that the <2 μm fraction of the core consists of both detrital dust and material produced during pedogenesis. An integrated analysis of records of χ, χ fd , grain-size (<2 μm) and clay minerals reveals that the pedogenic component of the <2 μm fraction is significantly anti-correlated with the >40 μm fraction and marine oxygen isotope record. Consequently, we conclude that the pedogenic component is a more accurate and sensitive indicator of weathering and soil formation than the χ record, and it is well suited to reconstructing high-resolution Quaternary climatic change in the western CLP. Furthermore, the proportion of the pedogenic component increased systematically over the past 2.2 million years, which may have been primarily caused by long-term global cooling since the Early Pleistocene together with the episodic uplift of the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Growing evidence highlights the potential consequences of long-term spaceflight, including gray matter volume reduction and cognitive dysfunction with subclinical manifestations of diabetes mellitus among astronauts, but the underlying mechanisms remain unknown. In this study, we found that long-term simulated weightlessness induced hippocampal insulin resistance and subsequent neuronal damage and cognitive impairment in rats. Rats subjected to 4-week tail suspension exhibited peripheral insulin resistance, evidenced by increased fasting blood glucose and abnormal glucose tolerance and insulin tolerance, alongside reduced spontaneous activity and impaired recognition memory. In addition, 4 weeks of simulated weightlessness induced neuronal apoptosis and degeneration in the hippocampus, as evidenced by increased TUNEL and Fluoro-Jade B staining-positive neurons. Mechanistically, insulin-stimulated hippocampal Akt phosphorylation was decreased, while PTEN, the negative regulator of insulin signaling, was increased in the hippocampus in tail-suspended rats. Interestingly, treatment with berberine, an insulin sensitizer, partly reversed the above-mentioned effects induced by simulated weightlessness. These data suggest that long-term simulated weightlessness induces cognitive impairment as well as neuronal apoptosis and neural degeneration, partially through hippocampal insulin resistance via PTEN up-regulation. Berberine treatment attenuates hippocampal insulin resistance and improves cognitive function. Schematic figure illustrating hippocampal insulin resistance induced by PTEN up-regulation involved in cognitive impairment induced by simulated weightlessness. Simulated weightlessness leads to hippocampal insulin resistance through up regulating the expression of PTEN and inhibiting Akt phosphorylation, which causes neuronal degeneration and apoptosis, and further results in cognitive dysfunction. Berberine attenuated simulated weightlessness-induced cognitive impairment by improving hippocampal insulin resistance via down-regulating PTEN and increasing the content of p-AktS473. [Display omitted] [ABSTRACT FROM AUTHOR]

Osteosarcoma (OS) is a common primary malignancy in children and adolescents with relative high survival rate after chemotherapy. While, the toxicity of chemotherapy and personalized different response to chemotherapy makes it difficult for the selection of therapeutics and improvement of diagnosis. In this study, we conducted a combined analysis of two types of microarray datasets (gene expression and DNA methylation) from the Gene Expression Omnibus (GEO). Differential methylation sites (DMS) were identified by the IMA package and differential expression genes (DEGs) were screened out via the limma package. A total of 11,242 DMS (corresponding to 3080 genes (DMGs)) and 337 DEGs, with 40 overlaps (OS genes) between DEGs and DMGs, were identified. Enriched functions of OS genes were obtained through the Database for Annotation, Visualization and Integrated Discovery (DAVID). The OS genes were mainly enriched in the biological processes related to inflammatory/immune response and Pertussis pathways and Hematopoietic cell lineage pathways. Besides, OS-specific disease network was obtained, and found that UBS and NRF1 were regulated by multiple OS genes. Kaplan Meier analysis of OS genes identified BHMT2, DOCK2, DNALI1 and RIPK3 as significant OS survival-related genes. SEMA3A and PRAME are included in the 40 OS genes and within the top 10 most up-regulated DEGs. Their expression changes were further validated in U2OS osteosarcoma cell lines and hOB normal cell lines through quantitative PCR (qPCR) and consistent result with microarray analysis was obtained. Based on this study, some novel targets were identified for OS, which would be helpful in its early diagnosis and treatment. [ABSTRACT FROM AUTHOR]

The Palaeogene evolution of the northeastern Tibetan Plateau remains elusive, because of the paucity of well-dated long-lasting and continuous sedimentary records. In this work, we present a detailed detrital apatite fission track thermochronology and stratigraphic study in the Lanzhou basin, located on the eastern-most margin of northeastern Tibet, where Eocene to middle Miocene sediments are well preserved. Combining the analysis of sedimentology records and synsedimentary tectonic structures, four regional tectonic phases are deciphered (52–47 Ma, 40–32 Ma, 23–20 Ma and <16 Ma, respectively). These episodes were spaced out by three periods of tectonic stability or quiescence linked to regional relief-reduction. Our apatite fission-track data suggest that far-field stress due to the India-Asia collision had been propagated to this region since early Eocene, and the modern northeastern portion of the Tibetan Plateau has been buildup since then. Thereafter, the growth of the northeastern Tibetan Plateau was dominated by a tectonic activity/inactivity cycle until late Miocene. Thus, the regional growth history appears to have been episodic in nature during the Cenozoic. [ABSTRACT FROM AUTHOR]

The Qaidam basin is the largest intermountain basin within the Tibetan Plateau. The spatio-temporal evolution of the basin and the provenances of the deposits in the SW Qaidam basin were greatly influenced by the boundary ranges. Comprehensive research is needed to identify the relationships between the basin and the surrounding ranges. Therefore, 4682 heavy mineral data from 70 wells and 720 detrital zircon ages from 8 samples were used to investigate the provenances of the deposits in the SW Qaidam basin and to further constrain the tectonic evolution of the boundary ranges. The heavy mineral data, zircon U-Pb ages, and paleocurrent data indicate that the Qimen Tagh Range and the Altyn Tagh Range were two provenances of the sediments deposited in the SW Qaidam basin during the Cenozoic. The variations of heavy mineral assemblages and ZTR index (100 ∗ (zircon + tourmaline + rutile)/total transparent heavy minerals) on the northern flank of the Qimen Tagh Range suggest that the Qimen Tagh Range experienced rapid uplift in the Early to Middle Miocene. Furthermore, according to the greatly increased quantities of epidote and hornblende sourced from the Altyn Tagh Range and the obvious decrease in the ZTR index values, the Altyn Tagh Range underwent fast uplift in the Late Oligocene to Early Miocene. In addition, based on the ages of the granitic plutons in the Altyn Tagh Range and the zircon ages in the Ganchaigou and Qigequan sections, the strike-slip movement of the Altyn Tagh Fault (ATF) initiated during or no later than the Middle Eocene, resulting in the ATF offsets of ca. 200 km between the Middle Eocene and the Miocene and of ca. 345 km between the Middle Eocene and the present. [ABSTRACT FROM AUTHOR]

The synorogenic basin deposits and bedrocks of their source terranes within and along the Tibetan Plateau contain fundamental information regarding the spatiotemporal evolution of the largest orogenic plateau on Earth. The Guide–Xining region is located on the northeastern portion of the Tibet and its Eocene–early Pleistocene basin succession is well preserved. By integrating apatite fission-track thermochronology from sedimentary and basement samples, with heavy minerals and paleocurrent data, we decipher an almost complete sequence of exhumation and depositional events during the Cenozoic. Our data indicates that the initial deformation along the Guide–Xining region occurred since the Eocene, with the reorganization of the regional tectonomorphology and the formation of a broad basin. Thereafter, this single large basin was disrupted by multiple episodes of exhumation and deformation. Our study illuminate that the multiple-stage active processes (occurred at 49–42, 36–32, 23–19, 16–13 and 8–4 Ma) work together to produce the current NE Tibetan Plateau. [ABSTRACT FROM AUTHOR]

The soil color is widely used in paleoclimate and paleoenvironment reconstructions in the Chinese Loess Plateau. To better understand the color spatial changes during the glacial–interglacial cycle, the soil color lightness ( L * ), characteristic spectra, magnetic susceptibilities and mean grain sizes of three loess–paleosol sequences were compared. Results showed that high L * and low hematite to goethite ratios (Hm/Gt) appeared in loess units, and low L * and high Hm/Gt ratios accompanied paleosol layers, indicating glacial–interglacial hydrothermal oscillation. L * in the Yulin section was higher than in the Chaona and Lihuacun sections, indicating that different precipitations have great effect on L * . Furthermore, Hm/Gt, magnetic susceptibility ( χ lf ), and mean grain size are correlated closely with L * . L * and Hm/Gt not only document climatic variations in the glacial–interglacial cycle vis - à - vis loess–paleosol sequences, but also can identify Heinrich cold events and millennial scale Dansgaard–Oeschger (D–O) warm events. It suggests that soil color responds sensitively to global climate change driven by ice volumes. L * and Hm/Gt curves exhibit higher frequencies and larger amplitudes than magnetic susceptibility ( χ lf ) curves, indicating that L * and Hm/Gt can be regarded as sensitive and reliable proxies for characterizing high-resolution climate change during the last glacial–interglacial cycle. [ABSTRACT FROM AUTHOR]

Nb-doped VO 2 microtube arrays were fabricated by a thermal oxidation process of V–Nb alloy foils in air. The Nb-doped VO 2 microtubes are featured with the rod-like, hollow, and rectangular cross-sectional single crystal, where arrays aligned nearly vertically on the surface of a Nb-doped V 2 O 5 substrate. Phase transition examinations demonstrate that Nb doping can decrease the metal-insulator transition temperatures of VO 2 by approximately 15 °C/at. % Nb, which reaches the highest decrease efficiency for metal-insulator transition temperatures of Nb-doped VO 2. The phase transition route and mechanism of Nb-doped VO 2 microtube arrays are revealed. • Nb-doped VO 2 microtube arrays were fabricated. • Nb doping can decrease the metal-insulator transition temperature of VO 2 by approximately 15 °C/at. % Nb. • The phase transition route and mechanism of Nb-doped VO 2 microtube arrays are revealed. [ABSTRACT FROM AUTHOR]