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The Indo-Pacific Warm Pool (IPWP) exerts a dominant role in global climate by releasing huge amounts of water vapour and latent heat to the atmosphere and modulating upper ocean heat content (OHC), which has been implicated in modern climate change1. The long-term variations of IPWP OHC and their effect on monsoonal hydroclimate are, however, not fully explored. Here, by combining geochemical proxies and transient climate simulations, we show that changes of IPWP upper (0–200 m) OHC over the past 360,000 years exhibit dominant precession and weaker obliquity cycles and follow changes in meridional insolation gradients, and that only 30%–40% of the deglacial increases are related to changes in ice volume. On the precessional band, higher upper OHC correlates with oxygen isotope enrichments in IPWP surface water and concomitant depletion in East Asian precipitation as recorded in Chinese speleothems. Using an isotope-enabled air–sea coupled model, we suggest that on precessional timescales, variations in IPWP upper OHC, more than surface temperature, act to amplify the ocean–continent hydrological cycle via the convergence of moisture and latent heat. From an energetic viewpoint, the coupling of upper OHC and monsoon variations, both coordinated by insolation changes on orbital timescales, is critical for regulating the global hydroclimate.

Clay minerals deposited at the southern Mendeleev Ridge in the Arctic Ocean have a unique provenance, which can be used to reconstruct changes in the local sedimentary environment. We show that sediments in core ARC7-E23 record high-frequency changes in clay minerals since the penultimate interglacial. The clay minerals, grain size, and ice-rafted debris indicate the extent of the East Siberia Ice Sheet (ESIS). During the glacial periods of Marine Isotope Stage 2 (MIS2) and MIS4, the southern Mendeleev Ridge was likely covered by an ESIS-extended ice shelf, blocking almost all sediment input from the Canadian Arctic and Laptev Sea, but allowing transport of fine-grained sediments from the East Siberian and Chukchi Sea shelves. After ESIS retreat, the Beaufort Gyre and Transpolar Drift became the primary transport mechanism for the distally sourced sediments. Climate conditions in MIS3 enhanced both the oceanic circulation and sediment transport.

Integration of perennial grass species into the current food production systems, especially in the agropastoral regions worldwide, may produce multiple benefits including, among others, a more stable productivity and a smaller eco-environmental footprint. However, one of the fundamental challenges facing the large-scale adoption of such grass species is their ability to withstand the vagaries of winter in these regions. Here, we present a comprehensive evaluation of the winter hardiness of 50 indigenous Chinese cultivars of alfalfa, a high-quality leguminous perennial grass, in comparison with six introduced U.S. cultivars in a multi-site field experiment in northern China. Our results reveal that indigenous cultivars have stronger winter hardiness than introduced cultivars. Cultivars native in the north performed better than southern cultivars, suggesting that suitability evaluation is an unavoidable step proceeding any regional implementations. Our results also show that the metric we used to assess alfalfa’s winter hardiness, the average score index (ASI), produced more consistent results than another more-widely used metric of winter survival rate (WSR). These findings offer a systematic field evidence that supports regional cropping system adjustment and production system betterment to ensure food security under climate change in the region and beyond.

The Indo-Pacific Warm Pool (IPWP) exerts a dominant role in global climate by releasing huge amounts of water vapour and latent heat to the atmosphere and modulating upper ocean heat content (OHC), which has been implicated in modern climate change

The accumulation of soil organic matter (SOM), poorly crystalline Fe oxides and metal-humus complexes is a trait of non-allophanic Andosols. The process of andosolization, which may occur in ferrallitic soils with high organic matter content, can involve transformation from well crystallized Fe oxides to poorly crystallized Fe oxides and Fe-humus complexes. This study investigates such changes in pedogenic Fe mineral associations for a soil toposequence between 1500 and 2260 m altitude along the southern flank of the volcanic Bambouto Mountains, Western Cameroon. The soils consist of highly weathered material, dominated by kaolinite, gibbsite and Fe oxides, grading to Protoandic Umbrisols at high altitude, recording an increase in SOM content with increasing altitude. As revealed by selective extraction analysis, the relative amount of poorly crystalline Fe oxides is low in the Bt and Bo horizons of low-altitude pedons, as well as in deep subsurface horizons of the high-altitude pedons. In contrast, it is significantly higher in the A and Bw horizons of the high-altitude pedons, with a clear increase with increasing altitude. Mossbauer spectroscopy analysis of B horizon samples identifies goethite as the dominant Fe oxide phase in nearly all pedons, with higher hematite contents in a mid-altitude zone marked by lower annual rainfall than in other parts of the toposequence. The Mossbauer spectra also reveal the presence of dissolved organic matter (DOM)-ferrihydrite, whose abundance is greatest in the Bw horizon of the high-altitude pedons, with an increase in relative abundance with increasing altitude. The observed patterns are attributed to dissolution-reprecipitation of Fe oxides that initially formed through ferrallitic weathering of volcanic parent materials that were roughly uniform along the toposequence. At high altitude, coupled hematite dissolution and DOM-ferrihydrite formation are favoured by high organic matter contents and low pH, related to cool humid environmental conditions and their effect on the vegetation and organic matter cycling.

A coupled approach based on grain size and geochemical elements is used to trace the provenance of surface sediments and to confirm the distribution patterns of grain size and elements on the continental shelf off western Guangdong Province and northeastern Hainan Island. The mean grain size ranges from 0.05 ϕ to 7.28 ϕ with a mean value of 5.60 ϕ. The average concentrations of major elements descend in the order of SiO2 >Al2O3 >CaO>Fe2O3 >K2O>MgO>Na2O>TiO2 >P2O5 >MnO, while those of trace elements exhibit a descending order of Sr>Rb >Zn>V>Cr>Pb>Ni>Cu>As>Cd. On the basis of the distribution patterns of elements and results of statistical analysis, the study area is classified into three zones. Zone I locates on the continental shelf off western Guangdong Province, and the sediments are mainly from Pearl River, Taiwanese rivers, and small rivers nearby. Zone II locates in the eastern exit of Qiongzhou Strait and the coastal area off Leizhou Peninsula, and the sediments are mainly from the erosion products of Qiongzhou Strait and Hainan Island. Zone III locates off the eastern Hainan Island and the continental shelf deeper than −50 m isobaths, and the sediments are mainly from Hainan Island and coral reef. The influence from open water should also be considered. Results indicate that the grain size is the main controlling factor for major and trace element contents and that anthropogenic impact and biological activity also play an important role in the distribution of these elements.

Soils along a toposequence (1500–2260 m) on the southern slope of the volcanic Bambouto Mountains in western Cameroon were investigated to elucidate the occurrence and development of andic properties at high altitude (>1800 m) in the study area. The surface layer that has these properties has in the past been interpreted as a weathered volcanic ash layer, overlying ferrallitic soils that developed from lava flow deposits and derived pediments. Physico-chemical and mineralogical data demonstrate that the andic properties of the high-altitude pedons result from SOM accumulation, favoured by climate and vegetation. The ‘andosolization’ process affecting these profiles involves the formation of organo-metallic complexes, which is mediated by organic ligands and controlled by the dissolution of gibbsite and iron oxides. Increasing andosolization with increasing altitude, due to SOM accumulation, is well reflected by soil classification names, especially by the humic qualifier for the soils below 1800 m a.s.l. and the protoandic subqualifier for the soils at higher altitude. All analysed properties show features that are incompatible with derivation of the upper part of the high-altitude pedons from volcanic ash. In studies of soils from similar settings, care should be taken to avoid misinterpretation of surface horizons marked by environmentally conditioned development of organo-metallic complexes as ash-derived layers.

A multi-index analysis including grain size, major and trace elements is performed on the surface sediments from the northeastern Beibu Gulf to trace the sources of the sediments and to understand the controlling factors for elements distribution. The mean grain size exhibits a wide variation ranging from 0.09Φ to 8.05Φ with an average value of 5.33Φ. The average contents of major elements descend in an order of c(SiO2)>c(Al2O3)>c(Fe2O3)>c(CaO)>c(MgO)>c(K2O)>c(Na2O)>c(TiO2)>c(P2O5)>c(MnO), while those of trace elements exhibit a descending order of c(Sr)>c(Rb)>c(V)>c(Zn)>c(Cr)>c(Pb)>c(Ni)>c(Cu)>c(As). On the basis of elementary distribution characteristics and statistical analyses, the study area is divided into the four zones: Zone I is located in the northeastern coastal area of the gulf, which receives large amount of fluvial materials from local rivers in Guangxi and Guangdong, China, and the Qiongzhou Strait; Zone II is located in the center of the study area, where surface sediments exhibits a multiple source; Zone III is located in the Qiongzhou Strait, where surface sediments are dominated by materials from the Zhujiang River and Hainan; Zone IV is located in the southwest of the study area, where surface sediments are mainly originated from the Red River and Hainan. The statistical analyses of sediment geochemical characteristics reveal that the grain size, which is mainly influenced by hydrodynamics and mineral composition of terrigenous materials, is the leading factor controlling the elementary distribution. Meanwhile, impacts from anthropogenic activities and marine biogenic process will also be taken into consideration.

Although many researchers have studied the antibacterial effects of gas discharge plasma in root canal disinfection, there are few studies on the potential of liquid discharge plasma in root canal disinfection. This study aimed to investigate the antibacterial effects of liquid discharge cold plasma (LDCP) on Enterococcus faecalis (E. faecalis) planktonic cultures and four-week-old root canal biofilms. Antibacterial efficacy was determined by the colony-forming unit method. Changes in the viability and surface morphology were studied by confocal laser scanning microscopy and scanning electron microscopy, respectively. The results showed that LDCP treatment had a significant antibacterial effect on planktonic E. faecalis, and had a better antibacterial effect on biofilms than 0.2% chlorhexidine treatment. The normal spherical structure of E. faecalis dissociated, and biofilm architectures were destroyed after LDCP treatment. This work opens doors to the potential application of using liquid discharge plasma devices for root canal treatment.

Tea, the world's second most popular drink, is an essential part of some people's lives. Thus, this study aimed to explore potential tea-drug interactions with a view to promoting the rational administration of drugs.A specific and sensitive approach involving high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and a probe cocktail was established and validated to evaluate the inhibitory effects of four teas on five cytochrome P450 (CYP450) enzymes in rats. Metoprolol tartrate (MT), omeprazole (OMP), phenacetin (PNT), tolbutamide (TOL), and testosterone (T) were selected as the probe drugs for CYP2D6, CYP2C19, CYP1A2, CYP2C6, and CYP3A1/2, respectively, and were simultaneously quantified in the multiple reaction monitoring (MRM) mode with positive electrospray ionization (ESI+) in a single 12-min run.The extraction recoveries, matrix effect values, as well as intra/interday accuracy and precision met the determination standards. CYP1A2 and CYP2C6 were strongly inhibited by green tea, and CYP2C6 was also strongly inhibited by Pu'er tea. Ti Kuan Yin tea had a weak inhibitory effect, and black tea had only a slight inhibitory effect, on CYP1A2. Furthermore, the four types of tea did not have significantly altered the activity of CYP2D6, CYP2C19, and CYP3A1/2The method used in the present study was successfully applied to assess the inhibitory effects of aqueous extracts of four types of tea on CYP450 isoforms

Orbitally driven warm pool upper-water temperature regulates the equatorial Pacific climate change over the past 25,000 years., Dynamics driving the El Niño–Southern Oscillation (ENSO) over longer-than-interannual time scales are poorly understood. Here, we compile thermocline temperature records of the Indo-Pacific warm pool over the past 25,000 years, which reveal a major warming in the Early Holocene and a secondary warming in the Middle Holocene. We suggest that the first thermocline warming corresponds to heat transport of southern Pacific shallow overturning circulation driven by June (austral winter) insolation maximum. The second thermocline warming follows equatorial September insolation maximum, which may have caused a steeper west-east upper-ocean thermal gradient and an intensified Walker circulation in the equatorial Pacific. We propose that the warm pool thermocline warming ultimately reduced the interannual ENSO activity in the Early to Middle Holocene. Thus, a substantially increased oceanic heat content of the warm pool, acting as a negative feedback for ENSO in the past, may play its role in the ongoing global warming.

Species composition and biomass are two important indicators in assessing the effects of restoration measures of degraded grasslands. In this paper, we present a field study on the temporal changes in plant community characteristics, species diversity and biomass production in a degraded temperate meadow steppe in response to an enclosure measure in Hulunbuir in Northern China. Our results showed that the plant community responded positively to the fence enclosure in terms of vegetation coverage, height, above- and belowground biomass. A year-to-year increase in aboveground biomass was observed, and this increase plateaued at the ninth year of the enclosure. Our results also showed that the existing dominant and foundation species gained predominance against other species. The sum of the biomass of these two species was more than doubled after the ninth year of the enclosure. However, belowground biomass only briefly increased until the fifth year of the enclosure and then decreased until the end of the experimental period. Plant diversity, evenness, and richness indices showed similar trends to that of belowground biomass. Overall, we found that the degraded temperate meadow steppe responded significantly positively to the enclosure treatment, but an optimal condition was only reached after approximately 5&ndash, 7 years of continuous protection, providing a solid use case for grassland conservation and management at regional scales.

Land use and its dynamics have attracted considerable scientific attention for their significant ecological and socioeconomic implications. Many studies have investigated the past changes in land use, but efforts exploring the potential changes in land use and implications under future scenarios are still lacking. Here we simulate the future land use changes and their impacts on ecosystem services in Northeast China (NEC) over the period of 2000–2050 using the CLUE–S (Conversion of Land Use and its Effects at Small regional extent) model under the scenarios of ecological security (ESS), food security (FSS) and comprehensive development (CDS). The model was validated against remote sensing data in 2005. Overall, the accuracy of the CLUE–S model was evaluated at 82.5%. Obtained results show that future cropland changes mainly occur in the Songnen Plain and the Liaohe Plain, forest and grassland changes are concentrated in the southern Lesser Khingan Mountains and the western Changbai Mountains, while the Sanjiang Plain will witness major changes of the wetlands. Our results also show that even though CDS is defined based on the goals of the regional development plan, the ecological service value (ESV) under CDS is RMB 2656.18 billion in 2050. The ESV of CDS is lower compared with the other scenarios. Thus, CDS is not an optimum scenario for eco-environmental protection, especially for the wetlands, which should be given higher priority for future development. The issue of coordination is also critical in future development. The results can help to assist structural adjustments for agriculture and to guide policy interventions in NEC.

Diabetes is one of the most serious metabolic diseases worldwide, and frequent monitoring of blood glucose is an essential part of diabetic management. However, a significant drawback of current monitoring methods was destructive and time-consuming. To meet this need, this study was to develop a method for rapid and noninvasive blood glucose assay in a skin tissue phantom by Near-Infrared spectroscopy (NIRS) and Raman spectroscopy. With partial least-squares (PLS) regression method, the multivariate calibration models of NIRS were generated and optimized individually by considering spectral region, spectral pretreatment methods and latent variables (LVs). The optimal NIR model was established with root mean square error of cross-validation (RMSECV) of 0.114, root mean square error of validation (RMSEP) of 0.061, correlation coefficient (R) of 0.9933, and residual predictive deviation (RPD) of 12.2, respectively. The validation results demonstrated that NIRS could be applied for rapid and noninvasive blood glucose assay.

Reclamation of degraded grasslands as managed grasslands has been increasingly accelerated in recent years in China. Land use change affects soil nitrogen (N) dynamics and nitrous oxide (N2O) emissions. However, it remains unclear how large-scale grassland reclamation will impact the grassland ecosystem as a whole. Here, we investigated the effects of the conversion from native to managed grasslands on soil N dynamics and N2O emissions by field experiments in Hulunber in northern China. Soil (0-10cm), nitrate (NO3-), ammonium (NH4+), and microbial N were measured in plots in a temperate steppe (Leymus chinensis grassland) and two managed grasslands (Medicago sativa and Bromus inermis grasslands) in 2011 and 2012. The results showed conversion of L. chinensis grassland to M. sativa or B. inermis grasslands decreased concentrations of NO3--N, but did not change NH4+-N. Soil microbial N was slightly decreased by the conversion of L. chinensis grassland to M. sativa, but increased by the conversion to B. inermis. The conversion of L. chinensis grassland to M. sativa (i.e., a legume grass) increased N2O emissions by 26.2%, while the conversion to the B. inermis (i.e., a non-legume grass) reduced N2O emissions by 33.1%. The conversion from native to managed grasslands caused large created variations in soil NO3--N and NH4+-N concentrations. Net N mineralization rates did not change significantly in growing season or vegetation type, but to net nitrification rate. These results provide evidence on how reclamation may impact the grassland ecosystem in terms of N dynamics and N2O emissions.

As a biological affinity chromatographic method, cell membrane chromatography (CMC) using a silica stationary phase covered with specific cell membrane has been used in screening active components....

BACKGROUND: Hyperuricemia is the only biochemical index in the classification of acute gouty arthritis in American Rheumatism Association 1977 and the main basis of clinical diagnosis for most doctors. However, nearly half of the time gout occurs without hyperuricemia, especially in an acute attack，which leads to an urgent need to find a new substitute diadynamic criteria of gout. Xanthine and hypoxanthine, as precursors of uric acid, have been reported to be high in gout patients with hyperuricemia and presumed to be gout biomarkers. OBJECTIVES: To further explore the possibility of xanthine and hypoxanthine to be gout biomarkers as substitutes for uric acid. METHODS: A reversed‐phase HPLC‐UV method was employed for simultaneous quantitative detection of uric acid (UA), xanthine (X), and hypoxanthine (HX) in gout patients’ (with and without hyperuricemia) and healthy persons’ serum. RESULTS: The xanthine and hypoxanthine concentrations in gout patients with hyperuricemia and without hyperuricemia are higher than in healthy persons with a P

Manganese (Mn) and cerium (Ce) are known as reactive metals sensitive to marine redox conditions, and can therefore serve as useful proxies for paleoceanographic environments. Quaternary sedimentary records in the Arctic Ocean show a consistent cyclicity of Mn enrichments, but Mn sources, transportation and deposition patterns, and relationship to paleoclimatic conditions are not well understood. Sediment core ARC3-B85D from the Alpha Ridge with the estimated stratigraphy covering ~350 kyr is used to investigate a coupled distribution of Mn and Ce in Quaternary Arctic Ocean sediments. By analyzing Mn and Ce distribution patterns in the core and surface sediments from the western Arctic Ocean and adjacent shelves, we investigate the conditions and dynamics of concurrent metal enrichments. Stratigraphic Ce and Mn patterns follow inferred glacial-interglacial cycles, with enrichments generally occurring during interglacial-type conditions with high sea levels. However, the relationships involved are not straightforward as highest Mn and Ce enrichments seem to occur closer to the end of interglacial/major interstadial periods, when sea levels were lowering from their highest positions. We conclude that the enrichment patterns are primarily defined by sediment dynamics controlling resuspension and transportation of reactive metals and their deposition in the central Arctic Ocean after diagenetic preconditioning on the shelves. We further infer that major transportation agents are sea-level affected cross-shelf and mid-depth ocean currents rather than sea ice as has been proposed earlier. Comprehending this coupled geochemical and sedimentary system is important for improving the chronostratigraphic framework for Quaternary deposits in the Arctic Ocean.

Sediment cores from the Northwind Ridge north of the Arctic Chukchi-Alaskan margin were analyzed for a suite of stratigraphic and provenance proxies. Based on the correlation to previously studied regional records, cores under study present sedimentary environments of Marine Isotope Stages (MIS) 1–11 (∼0.4 Ma) on millennial time scales. Contrasting glacial-interglacial conditions and provenance were characterized by means of clay-mineral and geochemical (elemental and isotopic) proxies along with grain size. Interglacial environments are interpreted as sea-ice dominated, with pre-Holocene sediment transported mostly from the East Siberian to Chukchi-Alaskan margin. In comparison with the recent conditions, this pattern suggests a stronger Transpolar Drift expanding into the Canada Basin at the expense of the Beaufort Gyre, or stronger along-shelf currents. Glacial intervals prior to MIS4 have a predominantly North American signature with carbonaceous or terrigenous source rocks. Carbonaceous inputs marked by Ca peaks are tracked to the western Canadian Arctic Archipelago eroded by the Laurentide Ice Sheet (LIS). Terrigenous sources (Zr peaks) are likely related to areas impacted by the Innuitian Ice Sheet and/or the LIS Mackenzie ice stream. MIS 4 and 2 intervals have a different composition with the Siberian/Chukchi rather than North American provenance. A stronger winnowing indicated by grain size in the glacial intervals suggests a stronger mid-depth circulation. Study results provide new boundary conditions for modeling paleocirculation and glaciations in the western Arctic Ocean.

Spatially explicit modeling techniques recently emerged as an alternative to monitor land use changes. This study adopted the well-known CLUE-S (Conversion of Land Use and its Effects at Small regional extent) model to analyze the spatio-temporal land use changes in a hot-spot in Northeast China (NEC). In total, 13 driving factors were selected to statistically analyze the spatial relationships between biophysical and socioeconomic factors and individual land use types. These relationships were then used to simulate land use dynamic changes during 1980–2010 at a 1 km spatial resolution, and to capture the overall land use change patterns. The obtained results indicate that increases in cropland area in NEC were mainly distributed in the Sanjiang Plain and the Songnen Plain during 1980–2000, with a small reduction between 2000 and 2010. An opposite pattern was identified for changes in forest areas. Forest decreases were mainly distributed in the Khingan Mountains and the Changbai Mountains between 1980 and 2000, with a slight increase during 2000–2010. The urban areas have expanded to occupy surrounding croplands and grasslands, particularly after the year 2000. More attention is needed on the newly gained croplands, which have largely replaced wetlands in the Sanjiang Plain over the last decade. Land use change patterns identified here should be considered in future policy making so as to strengthen local eco-environmental security.

A large ice sheet or ice shelf may have developed repeatedly along the East Siberian continental margin since the Middle Pleistocene. In combination with ice-rafted debris, major elements, and foraminifera, clay mineral records from four gravity sediment cores are used to trace ice events along the East Siberian continental margin during the last two glaciations. The clay mineral assemblages show a strong link to the extent of the East Siberian ice sheet (ESIS) rather than the ice shelf or icebergs sourced from the Canadian Arctic. During the last two glaciations, illite-rich sediment from East Siberia was transported mainly toward the deep basin, whereas kaolinite-rich sediment from the Canadian Arctic was mostly blocked from the East Siberian continental margin. We speculate that during marine isotope stage 2 (MIS2), the southern Mendeleev Ridge, Chukchi Basin, and Chukchi Rise may have been covered by an ESIS-extended ice shelf; however, the Chukchi Plateau and Northwind Ridge were dominated by a Laurentide-sourced ice shelf. During MIS4, the ESIS may have undergone a marked expansion, with an extended ice shelf occupying all of the Chukchi Plateau and Northwind Ridge, thereby restricting iceberg discharge from other ice sheets.

Acyclovir (ACV) is a synthetic antiviral agent with serious side effect, particularly its nephrotoxicity, so this study was to explore the ultrasensitive detection of ACV by surface-enhanced Raman scattering (SERS). The enhancement capability of nanoparticles prepared by different chemical reduction were compared, and Ag nanoparticles reduced by citrate are the most propriate enhanced substrate for acyclovir. In addition, comparison between prominent SERS-enhanced bands and the precise mode descriptions predicted through density functional theory (DFT) simulations is used to understand the mechanisms between ACV and metallic surface. 130 different levels of ACV concentrations in a range from 10-1∼10-7 were used to build quantitative prediction models by two different modeling methods, partial least-squares (PLS) regression and artificial neural network (ANN). Under the optimal conditions, the performance of the PLS model was much better than ANN. The results demonstrated that SERS imaging with multivariate analysis holds great potential for the sensitive and cost effective clinic test of ACV and its metabolites in biological fluids.