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The long-term aging behavior and corrosion resistance of Ni–25Cr–10Fe–xSi (x = 1, 2, 3, 4) alloys with varying Si content were systematically investigated. Ni–25Cr–10Fe–xSi alloys exhibited satisfactory mechanical properties even after aging at 650 °C for 5000 hours. The yield strength of the alloys exceeded 237 MPa, and the elongation exceeded 45.9 pct. No detrimental phases such as the η and σ phases precipitated during the long-term aging process, but Si segregation at grain boundaries in the form of carbides was observed. These carbides, while present, did not significantly affect the overall mechanical performance of the alloys. Meanwhile, the corrosion resistance of Ni–25Cr–10Fe–xSi alloys under the KCl–ZnCl2 deposit increased with the increase in Si content. The higher Si content promoted the formation of a protective corrosion scale rich in Cr and Si, which acted as a barrier, preventing the penetration of oxygen and molten salt into the substrate. Ni–25Cr–10Fe–xSi alloys are expected to be suitable materials for waste incineration equipment. [ABSTRACT FROM AUTHOR]

Endosymbiotic dinoflagellates in the family Symbiodiniaceae are physiologically and ecologically important for reef-building corals. Certain symbiotic lineages may provide adaptive functions that aid corals in coping with and surviving rapid environmental and climate changes; and thus, there is a growing interest in exploring Symbiodiniaceae communities and their associated roles. Steroid biomarkers have been proposed as a means of identifying species-specific symbionts, but their reliability has yet to be examined through comparison of different coral species that harbor known Symbiodiniaceae. Here, steroid molecular and δ13C analyses are applied to four stony corals that host identified (Porites lobata and Galaxea fascicularis) or undescribed (Goniopora tenuidens and Goniastrea minuta) Symbiodiniaceae to address this issue. The 23-Me C28Δ5,22, 23,24-Me C29Δ5,22, and dinosterol are characteristic of P. lobata; while, C29Δ5, gorgosterol, and 4α-methylgorgostanol are diagnostic for G. fascicularis, tracking the marked differences in their Symbiodiniaceae assemblages. These two steroid groups also exhibit largely similar (− 20.6 to − 17.0‰) and visibly variable (− 24.1 to − 17.3‰) δ13C signatures, following the low and high diversity of symbionts in P. lobata and G. fascicularis, respectively. Our present results, together with previous reports, clearly demonstrate the effectiveness of steroid molecular and δ13C features in depicting Symbiodiniaceae population, providing a useful complement to Symbiodiniaceae genetic analysis. A further comparison of steroid characteristics between unclear and known Symbiodiniaceae in our four corals reveals the almost identical symbiotic population between G. minuta and G. fascicularis and a restricted range of symbiotic composition in G. tenuidens that is shared with G. fascicularis (and G. minuta). Additionally, the occurrence of 5α-stanols suggestive of anaerobic conversion on Δ5-sterols implies complex steroid interactions within coral–algae–microbe holobionts. [ABSTRACT FROM AUTHOR]

Background: Accurate estimation of potential evapotranspiration (PET) is the key for studying land-air interaction hydrological processes. Several models are used to estimate the PET based on standardized meteorological data. Although combination-based models have the highest level performance estimation of PET, they require more meteorological data and may therefore be difficult to apply in areas lacking meteorological observation data. Results: The results showed significant differences in the spatial trends of PET calculated by different models in China, the Doorenbots–Pruitts model revealed the highest PET (1902.6 mm), and the Kuzmin model revealed the lowest PET (349.6 mm), with the largest difference being 5.5 times. The Romanenko and the Rohwer models were the recommended temperature-based and aerodynamic-based models. On the other hand, the Abtew model was more suitable for arid and semi-arid regions, while the Priestley–Taylor model was more suitable for humid regions. Combination-based models revealed ideal calculation accuracies, among which the Penman–Monteith model was the best option for PET calculation. Conclusions: The accuracy range of Romanenko, Rohwer, Abten, Priestley Taylor, and Penman Monteith models improved in MPZ and TCZ is higher than that improved in TMZ and SMZ. This does not mean that the improved models have higher accuracy in MPZ and TCZ than in TMZ and SMZ. On the contrary, the original model performed poorly in MPZ and TCZ, so the improved accuracy was relatively large. The unimproved model was already more suitable in TMZ and SMZ, so the improved accuracy was relatively small. Therefore, regional calibration of the PET models can improve the accuracy and applicability of PET calculation, providing a reference for studying hydrological processes in different climatic zones. [ABSTRACT FROM AUTHOR]

Long-chain n-alkanols and n-alkanes in core sediments from the northern South China Sea (SCS) were measured to make a comparison during terrestrial vegetation reconstruction from ~42 ka to ~7 ka. The results showed that terrestrial vegetation record from long-chain n-alkanes matched well with previous studies in nearby cores, showing that more C4 plants developed during the Last Glacial Maximum (LGM) and C3 plants dominated in the interglacial period. However, these scenarios were not revealed by terrestrial vegetation reconstruction using long-chain n-alkanols, which showed C3 plant expansion during the LGM. The discrepancy during the interglacial period could be attributed to the aerobic degradation of functionalized long-chain n-alkanols in the oxygen-rich bottom water, resulting in poor preservation of terrestrial vegetation signals. On the other hand, the different advantages of functionalized n-alkanols and non-functional n-alkanes to record local and distal vegetation signals, respectively, may offer a potential explanation for the contradiction during the LGM when the SCS was characterized by low-oxygen deep water. Nevertheless, large variations on n-alkyl lipid compositions in C3/C4 plants could play a part in modulating sedimentary long-chain n-alkanols and n-alkanes toward different vegetation signals, thereby suggesting that caution must be taken in respect to the terrestrial vegetation reconstruction using long-chain n-alkanes and long-chain n-alkanols. [ABSTRACT FROM AUTHOR]

Bifunctional electrocatalysts with high activity toward both oxygen reduction and evolution reaction are highly desirable for rechargeable Zn-air batteries. Herein, a kind of carbon nanotube (CNT) supported single-site Fe-N-C catalyst was fabricated via pyrolyzing in-situ grown Fe-containing zeolitic imidazolate frameworks on CNTs. CNTs not only serve as the physical supports of the Fe-N-C active sites but also provide a conductive network to facilitate the fast electron and ion transfer. The as-synthesized catalysts exhibit a half-wave potential of 0.865 V for oxygen reduction reaction and a low overpotential of 0.442 V at 10 mA·cm−2 for oxygen evolution, which is 310 mV smaller than that of Fe-N-C without CNTs. The rechargeable Zn-air batteries fabricated with such hybrid catalysts display a high peak power density of 182 mW·cm−2 and an excellent cycling stability of over 1,000 h at 10 mA·cm−2, which outperforms commercial Pt-C and most of the reported catalysts. This facile strategy of combining single-site Metal-N-C with CNTs network is effective for preparing highly active bifunctional electrocatalysts. [ABSTRACT FROM AUTHOR]

Lake level and its inferred East Asian summer monsoon (EASM) evolution in northern boundary of EASM during the Holocene are highly debated. Here, we present a 15-ka record of glycerol dialkyl glycerol tetraethers (GDGTs) in a closed lake in northern China to address this issue. Surface and downcore sediment data demonstrate sedimentary GDGT-0 and branched GDGTs (brGDGTs) are of aquatic production. Contents of GDGT-0 and brGDGTs increase but brGDGT-based paleo-temperature proxy decreases with water depth in surface sediments along a nearshore to offshore transect. This trend is likely due to an increasingly hypoxic condition, favored by anaerobic microbes producing these GDGT-0 and brGDGTs, in bottom water. Accordingly, brGDGT-derived water temperature and pH would reflect bottom water conditions that are largely regulated by water depth of the lake. Downcore GDGT data and their derived temperature and pH consistently reveal a gradually increasing lake level from the late Pleistocene to the early Holocene, a high level during 9.5–5 ka BP and a decreasing trend afterward. The lake-level records from independent and robust proxies in this study largely agree with pollen records in the region, supporting a mid-Holocene maximum EASM precipitation. [ABSTRACT FROM AUTHOR]

Background: Water migration and use are important processes in trees. However, it is possible to overestimate transpiration by equating the water absorbed through the plant roots to that diffused back to the atmosphere through stomatal transpiration. Therefore, it is necessary to quantify the water transpired and stored in plants. Method: The δ2H/δ18O technique and heat ratio method were used to explore the water usage of coniferous and broad-leaved tree species, including the proportions of water used for transpiration and water storage. Results: Platycladus orientalis and Quercus variabilis had strong plasticity in their water usage from different sources. Platycladus orientalis primarily used groundwater (30.5%) and the 60–100-cm soil layer (21.6%) throughout the experimental period and was sensitive to precipitation, absorbing water from the 0–20-cm layer (26.6%) during the rainy season. Quercus variabilis absorbed water from all sources (15.7%–36.5%) except from the 40–60-cm soil layer during the dry season. In addition, it did not change its water source but increased its groundwater uptake during the rainy season. The annual mean water fluxes of P. orientalis and Q. variabilis were 374.69 and 469.50 mm·year− 1, with 93.49% and 93.91% of the water used for transpiration, respectively. However, nocturnal sap flow in P. orientalis and Q. variabilis was mainly used for water storage in the trunk rather than transpiration, which effectively alleviated drought stress and facilitated the transport of nutrients. Conclusions: The water stored in both species comprised 6%–7% of the total water fluxes and, therefore, should be considered in water balance models. [ABSTRACT FROM AUTHOR]

The Silurian-Devonian interval is an essential period in Earth history for witnessing the rise of sarcopterygian fishes and terrestrial vascular plants. In addition to its implication in global stratigraphic correlation, the precise location of the Silurian-Devonian boundary (SDB) in East Yunnan closely relates to the minimal and maximal estimated dates for the lungfish-tetrapod split. Several geochemical indicators including the values and curves of δ13Corg, δ13Ccarb and TOC are obtained from the continuous SDB sequence in Dahe, Yiliang County, East Yunnan. The results reveal the significant positive δ13Corg shifts in the upper part of the Yulungssu Formation and the lower part of the Xishancun Formation, and the peak value (−20.0‰) in the sample YD-25 from the lowermost of the Xishancun Formation, replicating the δ13Corg variation trend from the uppermost Silurian to the lowermost Devonian worldwide. The δ13Corg variation across the SDB at the Dahe Section resembles the SDB curve from the borehole Klonk-1 drilled at the top of the Klonk GSSP in the Prague Basin, Czech Republic. As such, we place the SDB in the Dahe Area between the samples of YD-17 and YD-18 from the lowermost part of the Xishancun Formation. This SDB assignment is corroborated by new findings of Early Devonian thelodont Parathelodus from the lower part of the Xishancun Formation in Qujing Area. The resolution of the SDB in Dahe, coupled with available paleontological data and the biostratigraphic zonation in East Yunnan, has provided vital data for the geological ages of the fish-bearing strata in East Yunnan. The earliest rhipidistian Youngolepis from the Xishancun Formation (Lochkovian, Devonian) and earliest stem-sarcopterygian Psarolepis from the Kuanti Formation (Ludfordian, Silurian) in East Yunnan indicate that the split between lungfish and tetrapods occurred between 426.5 and 416.0 Ma. [ABSTRACT FROM AUTHOR]

Glycerol dialkyl glycerol tetraethers (GDGTs), specific membrane lipids synthesized mainly by bacteria and archaea, can be divided into isoprenoids and methyl branched alkyl GDGTs (iGDGTs and brGDGTs, respectively). Three GDGTs groups (iGDGTs, brGDGTs, and other membrane lipids) in a peat sample were separated and collected in this study using semi-preparative high-performance liquid chromatography (HPLC) and silica gel column chromatography. The obtained recoveries for the whole analytical procedure were 85%−55% using semi-preparative HPLC and 70%−20% using gel column chromatography. In addition, in each method, the recoveries of brGDGTs and iGDGTs were similar, regardless of the huge difference in their contents. High purity was found in the fractionated groups, determined based on ether cleavage and reduction. Moreover, the semi-preparative HPLC method could realize a better separation efficiency than the silica gel method, but it was time-consuming and required expensive equipment, while the silica gel chromatography method featured merits of time saving and convenient operation at the cost of a slight reduction in separation efficiency. The advantages of the silica gel method make it an operational laboratory method for batch experiments and isotopic studies. [ABSTRACT FROM AUTHOR]

The influence of past variations in water column denitrification (WCD) in the eastern tropical Pacific (ETP) on the western tropical Pacific (WTP) remains ambiguous, due to the deficiency of enough down-core records of nitrogen isotope (δ15N) in the WTP. In this study, sedimentary δ15N record down a core from the northern WTP is investigated to revisit this issue. After elucidating the potential presence of multiple forms of N by analyzing bulk parameters and the potential occurrence of alteration by examining amino acids, the bulk sedimentary δ15N can be accepted as an available indicator of nitrate δ15N. Further, a comprehensive comparison of δ15N records in the North Pacific reveals largely similar variations from the last glacial maximum to early Holocene, suggesting a common feature of WCD signals associated with basin-scale processes, likely as a consequence of basin-wide ocean circulations. Our result suggests that the signals of local N2 fixation in the western Pacific marginal seas would have been constrained by a synchronous glacial-interglacial change of the source WCD signals. [ABSTRACT FROM AUTHOR]

Aims: Water-use efficiency (WUE) is a key parameter to understand plant survival strategies and promote forest management in response to climate change. Here, the whole-plant instantaneous WUE (WUEi-P) and short-term WUE (WUEs-P) were investigated in response to soil water content (SWC) and atmosphere CO2 concentration (Ca). Methods: The WUEi-P was measured using a plant chamber and mini-lysimeters. The WUEs-P was estimated using different isotopic models. These estimates were compared with measured results (WUEs-P,mea; the ratio of the whole-plant cumulative CO2 assimilation to water loss). Results: Except at severe drought, WUEi-P generally decreased with increasing SWC, but increased with increasing Ca. At mild and moderate drought, the percentage increases in WUEi-P by elevating Ca from 600 to 800 μmol·mol−1 (23.45%–32.78%) were higher than those from 400 to 600 μmol·mol−1 (9.12%–8.33%). However, the opposite pattern was found under well- and excessive-watered conditions. The variation in WUEs-P,mea in response to Ca × SWC was similar to that in WUEi-P. The developed whole-plant isotopic model (i.e. the plant classical model) is based on the hypothesis that the mesophyll conductance (gm) should be considered to model whole-plant WUE. This model provided the best fit with WUEs-P,mea compared with previously proposed models (plant linear model, as well as leaf linear and classical model). This indicated that the contribution of gm, whole-plant respiration, and unproductive water loss should be considered when scaling from leaf to whole-plant level. Conclusions: These results have implications for mechanisms of plant water and carbon cycles and improve predictive capability for whole-plant WUE from δ13C. [ABSTRACT FROM AUTHOR]

Background: In the context of a warming climate and dry conditions, aggravating water shortages, research on partitioning total evapotranspiration (ET) into soil evaporation (E) and plant transpiration (T) is needed.Methods and aims: Recently, using the oxygen isotope ratio as a tracer has proved to be a valuable way to better partition ET. In this study, we carefully considered the process of heavy water fractionation during the transpiration process, and specifically, we modified the kinetic fractionation coefficient (αk2) of transpiration, based on previous formulations used to estimate it.Results: Our results show that, for the hourly and daily mean data set, both the isotopic-steady-state (ISS) and non-steady-state (NSS) assumptions for δ18O of leaf water (δL,b) provided a good fit with observed δL,b when using the modified αk2. In contrast, using αk2 values traditionally assigned led to significant deviations from observed δL,b (p < 0.05), potentially influencing ET partitioning results. On diurnal time scales, the percent contribution of T to total ET (FT) is sensitive to different model assumptions and different formulations to estimate αk2. The modeled FT, assuming NSS conditions and using the modified αk2 value, led to the best agreement with observed values. In contrast, on longer time scales (days), using the ISS assumption to partition ET is adequate, as the NSS assumption could introduce more complexities and uncertainties.Conclusions: Our study demonstrates that the stable isotope technique is a promising utility for quantitatively partitioning ET. To more accurately estimate FT, we also call on a better description of the nature of αk2 of transpiration. [ABSTRACT FROM AUTHOR]

Background: The present study examined the validity of a university-based speaking assessment (Test of Oral Proficiency in English, TOPE for short) in mainland China. The speaking assessment was developed to meet the standards (Standard for Oral Proficiency in English, SOPE for short) set for teaching and learning of the oral English by the university. Methods: The degree of interaction among candidates in the second part of the test (Presentation and Discussion) was analyzed in terms of frequency of the language functions. These functions were reflected in the test syllabus, which was developed based on the CEFR. Results: Quantitative analysis revealed that majority of language functions intended by the test syllabus has been elicited in candidate performances. At the same time, students showed a relatively lack of interactional functions. Further qualitative investigations identified some speaking features that have the potential to affect scores of the candidate. Conclusions: Merits and limitations of using the CEFR for developing the speaking assessment (i.e., applicability of the CEFR for TOPE) were discussed. The study was concluded with its limitations and suggestions for future study. [ABSTRACT FROM AUTHOR]

This study investigated the composition of long-chain alkyl diols, triols, sec-alcohols, hydroxyl acids, and other hydroxylated compounds in Azolla imbricata and compared the organic alcohol components of Azolla filiculoides, Azolla microphylla, and South China Sea (SCS) sediments in order to investigate the possible indication of Azolla being the biological source of diols and triols in SCS sediment. Large amounts of diols, monohydroxy acids, and sec-alcohols with internal hydroxy groups at ω20 were detected in the three types of Azolla. Among these, 1,ω20-diol and ω20-hydroxy acid exhibited strong even-odd predominance distribution, whereas ω20- sec-alcohol exhibited strong odd-even predominance distribution. In addition, small amounts of diols, triols, and dihydroxy acids with internal hydroxy groups at 9, 10 or ω9, ω10 were detected, among which the chain length of C was predominate. Compounds having similar structures as those in Azolla reflected a similar biosynthetic pathway: ω20-hydroxy acid exhibiting even-odd predominance distribution is decarboxylated to ω20- sec-alcohol exhibiting odd-even predominance distribution and converted to 1, ω20-diol with even-odd predominance distribution by acyl reduction; ω9, ω10-hydroxy acid is converted to 1,20,21(1, ω9, ω10)-triol by acyl reduction, and then converted to 9,10-diol by hydrogenation and dehydration. The alcohol components in A. imbricata were clearly not the biological source of 1,13/1,14/1,15-C diols and 1,3,4-C triols in the SCS sediment. Certain marine diatoms might be the source of 1,14-C diol in inshore sediment, but the biological source of diols and triols in the SCS sediment requires further investigation. [ABSTRACT FROM AUTHOR]

After the detection of the 1,20,21-C long-chain triol in some sediments and freshwater pteridophytes, in this study, a new homologous long-chain triol, 1,3,4-C, is detected for the first time in the Site4B core sediment in the northern South China Sea. The hydroxyl location and length of the carbon chain of this newly discovered triol differ from those of 1,20,21-C triol. The test results of its molecular distribution and individual carbon isotope reveal that 1,3,4-Ctriol has a good correlation with n-C even carbon-numbered long-chain fatty alcohols, with R ( n=68) values of 0.905, 0.929 and 0.903, respectively, and its carbon isotope composition, at-32.3‰±1.9‰, is similar to that of n-C, at-29.13‰±0.87‰,-32.98‰±1.28‰, and-32.98‰±1.28‰. 1,3,4-C triol from the Site4B core sediment and terrigenous long-chain fatty alcohol ( n-C) show highly consistent distribution trends in the entire section; thus, the former could serve as a proxy indicator of the terrigenous input. Considering that the 1,20,21-C triol in previous research belongs to Azolla, which are fresh water pteridophytes, the 1,3,4-C triol identified in this study might have similar biogenetic derivation. Thus, determination of its biogenic area and growing environment could provide potential organic geochemical evidence supporting the terrigenous input and source in the northern South China Sea. [ABSTRACT FROM AUTHOR]

The compound-specific stable carbon isotope compositions ( δC) of leaf wax n-alkanes from two short sediment cores recovered off the Pearl River estuary (PRE) were analyzed to check for their capability of indicating decadal scale catchment environmental change. Sedimentary long-chain n-alkanes exhibited an odd-over-even predominance, with a maximum at n-C or n-C, indicating their leaf wax origin was from vascular plants. The δC values of C and C n-alkane in all the sediment samples were in the range of -28.8‰ to -31.2‰, consistent with the C plant-dominated vegetation in the Pearl River catchments. The time series of δC records from the two cores were comparable and displayed a decreasing trend from the early 20th century to the end of the 1970s, followed by a reversal in that change leading to continued increase for ca. 15 years. After being corrected for the effect of atmospheric CO rise and δC decline, the δC records largely retained their raw changing pattern; the post-1980 increase being more conspicuous. The slightly decreasing trend in corrected δC records before around 1980 may have been caused by an increase in precipitation, whereas the subsequent increase of δC is likely associated with the observed dry climate and/or intensive anthropogenic deforestation. Our results thus demonstrate that leaf wax n-alkanes buried in the sediments off the PRE may well reflect change in the regional climate and/or human activity in the river catchments over the past century. [ABSTRACT FROM AUTHOR]

The Changjiang Estuary has been considered as one of the most polluted estuaries in the world due to high nitrate (NO) input, especially in spring and summer. In this study, δN and δO of NO, along with other chemical parameters in this area, were measured in spring to evaluate NO biogeochemical processes. A simple two end-members mixing model was used to examine the relative contribution of the Changjiang River Diluted Water and marine water to NO sources in the Changjiang Estuary and the adjacent East China Sea. The isotopic signals show that NO behaved relatively and conservatively in Transect F and Transect P where assimilation was weak possibly due to vertical mixing, while active assimilation and weak nitrification occurred in Transect D. Spatial difference in assimilation was indicated by the ∼1:1 enrichment of δN and δO in the three transects, while spatial difference in nitrification was reflected by deviations of δN and δO from assimilation line. Our results suggest that the input of the Changjiang River Diluted Water promoted NO assimilation possibly by stratifying the water column which favored the phytoplankton growth. [ABSTRACT FROM AUTHOR]

Magnetic parameters have been widely used as a rapid, cost-effective, and non-destructive method. To assess whether their magnetic properties reflect the development history in the Pearl River Delta, three sediment cores collected from South China coastal waters were selected for magnetic research. The results indicate that the predominant ferrimagnetic mineral is magnetite, with an additional smaller amount of surprisingly high-coercive greigite. Fine-grained superparamagnetic and single-domain particles of magnetite and the relative contribution of greigite are increased when the total concentration of ferrimagnetic minerals is higher. Three well-known stages of the Chinese history, i.e., iron smelting, cultural revolution, and the latest phase of opening and reforming were identified in the vertical variation of magnetic concentration parameters. Although the record of the three cores is not completely consistent, the results point out that magnetic concentration parameters can reflect the development and pollution history in surrounding coastal areas. [ABSTRACT FROM AUTHOR]

To investigate characteristics of H isotope variation in long-chain n-alkanes ( δD) from higher plants in surface soils under a single ecosystem, 12 samples from a basalt regolith were randomly collected from Damaping in Wanquan County of Zhangjiakou in North China. Molecular distribution and C ( δC) and H isotopes of long-chain n-alkanes, as well as C isotopes of TOC ( δC), were analyzed. Both δC and δC values from four representative dominant long-chain n-alkanes ( n-C, n-C, n-C, n-C) derived from terrestrial higher plants show minor variations among the 12 samples, indicating the major contributor is from local grasses with a uniform C3 photosynthetic pathway. In contrast, variations in δD values of the four long-chain n-alkanes are relatively large, with the more abundant homologs generally showing more negative δD values and less variation. However, variation of <30‰ among weighted averaged δD values of the four long-chain n-alkanes is not only less than that among δD values for different modern terrestrial C grasses from the specific locations, but also less than the literature values of δD of long-chain n-alkanes for single species over different seasons. Thus, because the sources of long-chain n-alkanes in surface soils and sediments are similarly from multiple individual plants, our results are significant in confirming that paleoclimatic, paleoenvironmental and paleohydrological information can be interpreted more accurately from δD values of long-chain n-alkanes from sediments, particularly terrestrial sediments with organic matter derived from in-situ plants. [ABSTRACT FROM AUTHOR]

The molecular distribution of long-chain n-alkanes in 62 soil samples collected from diverse locations across eastern China was analyzed. The long-chain n-alkanes were mostly dominated by n-C or n-C, regardless of the overlying vegetation type at each site. The results were compared with those summarized from the literature, covering more than 100 soil samples within China and more than 300 genera of modern plants distributed worldwide. There were similar n-alkane distribution patterns for most genera, with no clear differences among grasses, shrubs, and trees. The evidence from analyses of surface soils and modern plants indicates that the relationship between the molecular distribution of long-chain n-alkanes of surface soils and source vegetation is highly complex, and is influenced by many factors. Further, it is suggested that source vegetation types should not be simply inferred from distribution patterns of long-chain n-alkanes in sediments. [ABSTRACT FROM AUTHOR]

Using -24‰ and -14‰ as the endpoints of stable carbon isotopic composition of total organic carbon (δ13 CTOC) of surface soil under pure C3 and C4 vegetation, and surface soil δ13 CTOC data from eastern China, Australia and the Great Plains of North America, we estimate the relative abundance of C3/C4 plants (i.e., the ratio of C3 or C4 biomass to local primary production) in modern vegetation for each region. The relative abundance of modern C3/C4 vegetation from each region is compared to the corresponding climatic parameters (mean annual temperature and precipitation) to explore the relationship between relative C4 abundance and climate. The results indicate that temperature controls the growth of C4 plants. However, even where temperature is high enough for the growth of C4 plants, they will only dominate the landscape when precipitation declines as temperatures increase. Our results are consistent with those of other investigations of the geographic distribution of modern C4 plant species. Therefore, our results provide an important reference for interpretation of past C3/C4 relative abundance records in these three regions. [ABSTRACT FROM AUTHOR]

Anion-exchange superporous cellulose (DEAE-SC) and microporous cellulose (DEAE-MC) adsorbents were packed in an electrochromatographic column, and the effect of external electric field (eEF) on the dynamic adsorption was investigated. The column was designed to provide longitudinal, transverse or 2-dimensional (2D) eEF. It was found that the electro-kinetic effect caused by the introduction of an electric field played an important role in the dynamic adsorption of bovine serum albumin to the adsorbents. The dynamic binding capacity (DBC) in the presence of 2D eEF was higher than in the presence of a one-dimensional eEF. The effect of flow velocity on the DBC of the two adsorbents was also demonstrated. It was found that the effect of electric field on the DEAE-MC column was more remarkable than that on the DEAE-SC column at the same flow rate, whereas the DEAE-SC column showed higher DBC and adsorption efficiency (AE) than the DEAE-MC column. With increasing flow rate, the DEAE-SC column could still offer high DBC and AE in the presence of the 2D eEF. For example, a DBC of 21.4 mg/mL and an AE of 57.7% were obtained even at a flow rate as high as 900 cm/h. The results indicate that the 2D electrochromatography packed with the superporous cellulose adsorbent is promising for high-speed protein chromatography. [ABSTRACT FROM AUTHOR]

Carbon Preference Index (CPI values) of higher plant-derived long-chain n-alkanes extracted from 62 surface soil samples in eastern China exhibited a specific pattern of variations, namely gradual increase with the increasing latitudes. Such regular variations existed in both forest soil and grassland soil. Our data implied that CPI values of higher plant-derived long-chain n-alkanes had a certain connection with climatic conditions, and such a connection was not influenced by vegetation types. Together with previous data from marine sediments, loess/paleosol sequences, tertiary red clay and modern plants, our observation made us conclude that CPI values of higher plant-derived long-chain n-alkanes may be used as an excellent proxy for paleoclimatic studies. [ABSTRACT FROM AUTHOR]

Surface soil samples collected over a high spatial resolution in eastern China were analyzed for carbon Isotope composition (δ13C) of total organic carbon (TOC) and higher plant-derived long-chain n-alkanes, with the latter reported as weighted mean values. The two sets of δ13C values are significantly correlated and show similar trends in spatial variation. The spatial distribution of δ13C shows less negative values in the mid-latitudes between 31°N and 40°N and more negative ones at higher and lower latitudes. This is consistent with previously reported carbon isotope data from surface soil phytoliths in the same region and suggests that the mid-latitude area provides relatively favorable growing conditions for C4 plants. Furthermore, δ13C values of both TOC and long-chain n-alkanes from 12 surface soil samples collected from a small grassland in north China displayed similar carbon isotope values and the difference between paired δ13C of a soil samples remains relatively constant. Our data demonstrate that in eastern China, soil δ13C composition of both TOC and long-chain n-alkanes is effective indicators of C3/C4 ratios of the prevailing vegetation. This work suggests that -22% and -32% are good estimated end members for the weighted mean δ13C values of long-chain n-alkanes (C27, C29 and C31 n-alkanes) from soils under dominant C4 or C3 vegetation, allowing us to reconstruct paleovegetation trends. [ABSTRACT FROM AUTHOR]

Based on new and existing data on oxygen isotopes, alkenone-surface seawater temperature trends, planktonic foraminifers, lithology, and clay mineral composition of piston cores, a distinct cooling event has been identified around 8,200 cal a b. p. in the middle Okinawa Trough, northwest Pacific. This corresponds to the 8,200 a b. p. cooling event recorded in many places of the Northern Hemisphere. During this event, the local temperature decreased by 1°C, and the δ18O value increased by 0.6‰. A strengthened Asian winter monsoon is the most probable cause for this event, which thus adds further credibility to the contention that we are dealing here with a global phenomenon. [ABSTRACT FROM AUTHOR]

Reports that the reconstruction of pCO2 in the tropic ocean is one of the important issues to understanding global climatic changes. Description of the study, in which the high-resolution stratigraphic analysis of core 17962 was conducted, located in the southern South China Sea (SCS); Consideration of the contents of sedimentary organic matter, the stable carbon isotopic composition of sedimentary organic matter, and other indicators; Results of the study, which show that the average pCO2 was estimated at 240 ppmV during the last glaciation, and at 320 ppmV in the Holocene.

Presents a study on the sedimentary records of Black Carbon (BC) in the sea area of the Spratly Islands. Definition of BC; Sample and measurements of BC; Results and analysis.

Reports on the long-chain alkenones present in the shallow sediment of Hotong Qagan Nur Lake in China. Information on the lake; Samples and experiments; Results and discussion.

Gene therapy and viral vaccine are becoming attractive therapeutic options for the treatment of different malignant diseases. Viral vector productions are often using static culture vessels and small volume stainless steel bioreactors (SSB). However, the yield of each vessel can be relatively low and multiple vessels often need to be operated simultaneously. This significantly increases labor intensity, production costs, contamination risks, and limits its ability to be scaled up, thus, creating challenges to meet the quantities required once the gene therapy or viral vaccine medicine goes into clinical phases or to market. Single-use bioreactor combining with microcarrier provides a good option for viral vector and vaccine production. The goal of the present studies was to develop the microcarrier bead-to-bead expansion and transfer process for HEK293T cells and Vero cells and scale-up the cultures to 50–200 l single-use bioreactors. Following microcarrier bead-to-bead transfer, the peak cell concentration of HEK293T cells reached 1.5 × 106 cells/ml in XDR-50 bioreactor, whereas Vero cells reached 3.1 × 106 cells/ml and 3.3 × 106 cells/ml in XDR-50 bioreactor and XDR-200 bioreactor, respectively. The average growth rates reached 0.61–0.68/day. The successful microcarrier-based scaleup of these two cell lines in single-use bioreactors demonstrates potential large-scale production capabilities of viral vaccine and vector for current and future vaccines and gene therapy. [ABSTRACT FROM AUTHOR]

To identify a vegetation configuration pattern with a high-efficiency purification ability for total nitrogen (TN), available nitrogen (AN), total phosphorous (TP), available phosphorous (AP), and chemical oxygen demand (COD) based on comprehensive assessment results, a water discharge experiment was performed in the Luan River in China with the following riparian forests: I, pure broad-leaved; II, mixed broad-leaved; III, mixed coniferous and broad-leaved; IV, mixed coniferous; and V, pure coniferous. From the riparian buffer zone to the river channel, the evaluation showed that pattern I had the highest purification ability at 1 m and 2 m; at a width of 4 m, pattern III had the highest purification ability; at a distance of 7 m, pattern V showed the highest purification ability; at 10 m, pattern IV showed the highest purification ability, pattern II the lowest. It is advisable to give priority to plant coniferous species from 0 m to 4 m from the river bank, while it is advisable to give priority to plant broad-leaved species from 4 m to 10 m from the river bank. We therefore recommend these vegetation configuration patterns in the development and management of runoff purification systems. [ABSTRACT FROM AUTHOR]