Source apportionment of methane escaping the subsea permafrost system in the outer Eurasian Arctic Shelf

The East Siberian Arctic Shelf holds large amounts of inundated carbon and methane (CH₄). Holocene warming by overlying seawater, recently fortified by anthropogenic warming, has caused thawing of the underlying subsea permafrost. Despite extensive observations of elevated seawater CH₄ in the past decades, relative contributions from different subsea compartments such as early diagenesis, subsea permafrost, methane hydrates, and underlying thermogenic/ free gas to these methane releases remain elusive. Dissolved methane concentrations observed in the Laptev Sea ranged from 3 to 1,500 nM (median 151 nM; oversaturation by ∼3,800%). Methane stable isotopic composition showed strong vertical and horizontal gradients with source signatures for two seepage areas of δ¹³C-CH₄ = (−42.6 ± 0.5)/(−55.0 ± 0.5) ‰ and δD-CH₄ = (−136.8 ± 8.0)/(−158.1 ± 5.5) ‰, suggesting a thermogenic/natural gas source. Increasingly enriched δ¹³C-CH₄ and δD-CH₄ at distance from the seeps indicated methane oxidation. The Δ¹⁴C-CH₄ signal was strongly depleted (i.e., old) near the seeps (−993 ± 19/−1050 ± 89‰). Hence, all three isotope systems are consistent with methane release from an old, deep, and likely thermogenic pool to the outer Laptev Sea. This knowledge of what subsea sources are contributing to the observed methane release is a prerequisite to predictions on how these emissions will increase over coming decades and centuries.

The East Siberian Arctic Shelf (ESAS) is the world’s largest and shallowest shelf sea system, formed through inundation of northeast Siberia during sea level transgression in the early Holocene. The ESAS holds substantial but poorly constrained amounts of organic carbon and methane (CH₄). These carbon/methane stores are contained in unknown partitions as gas hydrates, unfrozen sediment, subsea permafrost, gas pockets within and below the subsea permafrost, and as underlying thermogenic gas (1–3). Methane release to the atmosphere from these compartments could potentially have significant effects on the global climate (4, 5), yet there are large uncertainties regarding the size and the vulnerability toward remobilization of these inaccessible and elusive subsea carbon/methane pools. Conceptual development and modeling have predicted that warming of the ESAS system by a combination of geothermal heat and climate-driven Holocene heat flux from overlying seawater, recently further enhanced by Anthropocene warming, may lead to thawing of subsea permafrost (6, 7). Subsea permafrost drilling in the Laptev Sea, in part at the same sites as 30 y ago, has recently confirmed that the subsea permafrost has indeed come near the point of thawing (8). In addition to mobilization of the carbon/methane stored within the subsea permafrost, its degradation can also lead to the formation of pathways for gaseous methane from underlying reservoirs, allowing further methane release to the overlying water column (3, 9).Near-annual ship-based expeditions to the ESAS over the past two decades have documented widespread seep locations with extensive methane releases to the water column (3, 10). Methane levels are often found to be 10 to 100 times higher than the atmospheric equilibrium and are particularly elevated in areas of strong ebullition from subsea gas seeps (“methane hotspots”). Similarly, elevated dissolved methane concentrations in bottom waters appear to be spatially related to the thermal state of subsea permafrost as deduced from modeling results and/or geophysical surveys (7, 9). Currently, we lack critical knowledge on the quantitative or even relative contributions of the different subsea pools to the observed methane release, a prerequisite for robust predictions on how these releases will develop. An important distinction needs to be made between pools that release methane gradually, such as methane produced microbially in shallow sediments during early diagenesis or in thawing subsea permafrost, versus pools with preformed methane that may release more abruptly once pathways are available, such as from disintegrating methane hydrates and pools of thermogenic (natural) gas below the subsea permafrost. Multidimensional isotope analysis offers a useful means to disentangle the relative importance of these different subsea sources of methane to the ESAS: Stable isotope data (δ¹³C-CH₄ and δD-CH₄) provide useful information on methane formation and removal pathways, and the radiocarbon content of methane (Δ¹⁴C-CH₄) helps to determine the age and methane source reservoir (see SI Appendix, text S1 for details on these isotope systematics and typical isotopic signatures for the ESAS subsea system).Here, we present triple-isotope–based source apportionment of methane conducted as part of the Swedish–Russian–US investigation of carbon–climate–cryosphere interactions in the East Siberian Arctic Ocean (SWERUS-C3) program. To this end, the distribution of dissolved methane, its stable carbon and hydrogen isotope composition, as well as natural radiocarbon abundance signature, were investigated with a focus on the isotopic fingerprint of methane escaping the seabed to pinpoint the subsea sources of elevated methane in the outer Laptev Sea.     

海参EPA-PC对非酒精性脂肪肝大鼠三酰甘油代谢的改善作用

摘要：目的 探究海参磷脂型二十碳五烯酸（EPA-PC）对非酒精性脂肪肝（non-alcoholic fatty liver disease, NAFLD）大鼠甘油三酯代谢的影响。方法 采用饮食中添加乳清酸的方法诱导建立NAFLD大鼠模型。雄性Wistar大鼠随机分为5组,分别为正常组、模型组、洛伐他汀对照组、EPA-PC高、低剂量组。饲喂3周后,检测大鼠肝脏及血清中总胆固醇（Total cholesterol,TC）及甘油三酯（Triglycerides,TG）含量;RT-PCR法检测大鼠肝脏中TG合成相关基因GPAT和DGAT,TG分解相关基因ATGL和HSL以及AMPK信号通路相关基因CAMKK和LKB1 mRNA的表达水平。结果 EPA-PC可以显著降低NAFLD大鼠血清和肝脏中TG和TC的含量,显著下调GPAT、DGAT和HSL的表达,显著上调ATGL和AMPK信号通路相关基因表达。结论 EPA-PC可以通过抑制TG合成,促进TG分解,并激活AMPK信号通路,从而改善NAFLD大鼠的TG的代谢。     

Multidetector Computed Tomographic Anatomy of the Lungs in the Loggerhead Sea Turtle (Caretta caretta)

Multidetector computed tomographic (CT) anatomy was used to evaluate the lungs of 10 loggerhead sea turtle (Caretta caretta) without pulmonary disease, in order to provide a baseline of turtle lung anatomy by CT imaging. In all patients, in this retrospective anatomic study, the CT datasets were carefully evaluated for assessment of the bronchial tree morphology and branching pattern, of the arborization pattern of pulmonary arteries and veins and of the bronchoarterial–bronchovenous diameter ratios. Imaging anatomy was compared with previous published data based on dissection and microscopic anatomy. With the increasing availability of advanced imaging tools for wildlife animal patients, a detailed CT anatomy background is required to decipher correctly the pathologic respiratory conditions of sea turtles. Anat Rec, 302:1658–1665, 2019. © 2018 American Association for Anatomy     

Antibody profiling using a recombinant protein–based multiplex ELISA array accelerates recombinant vaccine development: Case study on red sea bream iridovirus as a reverse vaccinology model

Predicting antigens that would be protective is crucial for the development of recombinant vaccine using genome based vaccine development, also known as reverse vaccinology. High-throughput antigen screening is effective for identifying vaccine target genes, particularly for pathogens for which minimal antigenicity data exist. Using red sea bream iridovirus (RSIV) as a research model, we developed enzyme-linked immune sorbent assay (ELISA) based RSIV-derived 72 recombinant antigen array to profile antiviral antibody responses in convalescent Japanese amberjack (Seriola quinqueradiata). Two and three genes for which the products were unrecognized and recognized, respectively, by antibodies in convalescent serum were selected for recombinant vaccine preparation, and the protective effect was examined in infection tests using Japanese amberjack and greater amberjack (S. dumerili). No protection was provided by vaccines prepared from gene products unrecognized by convalescent serum antibodies. By contrast, two vaccines prepared from gene products recognized by serum antibodies induced protective immunity in both fish species. These results indicate that ELISA array screening is effective for identifying antigens that induce protective immune responses. As this method does not require culturing of pathogens, it is also suitable for identifying protective antigens to un-culturable etiologic agents.     

茯苓、枸杞、黄芪提取物和海参冻干粉配伍增强免疫力作用的实验研究

目的:观察茯苓提取物、枸杞提取物、黄芪提取物和海参冻干粉配伍制成混合物的增强免疫力作用。方法:按《保健食品检验与评价技术规范》中免疫力功能检验方法,经口给予小鼠200 mg/(kg·bw)、400 mg/(kg·bw)、1000 mg/(kg·bw)剂量30 d,测定细胞免疫、体液免疫、单核-巨噬细胞吞噬功能指标及NK细胞活性。结果:高剂量组足跖肿胀度、抗体生成细胞数、半数溶血值、NK细胞活性、吞噬鸡红细胞的吞噬指数均显著高于阴性对照组(P<0.05),实验组能显著提高迟发型变态反应能力、小鼠抗体生成细胞数、血清溶血素水平、巨噬细胞吞噬鸡红细胞的能力和NK细胞活性。各剂量组对小鼠体质量增长、胸腺/体质量比值、脾脏/体质量比值、淋巴细胞增殖能力、单核-巨噬细胞碳廓清能力均无显著影响(P>0.05)。结论:茯苓提取物、枸杞提取物、黄芪提取物和海参冻干粉配伍制成的混合物具有增强免疫力作用。     

大连傅家庄海滨疗养区的特点

目的本文综述了大连傅家庄海滨疗养区的微小气候特点、空气负离子浓度、夏季水、气、沙温度变化、日光辐射强度及日光浴和海水浴对机体的影响研究近况。并说明其医疗价值。方法查阅资料并在日光浴和海水浴后，检测血脂、血粘度及免疫功能。结果疗养后血清胆固醇降低、免疫功能增强、血脂明显下降、血粘度降低。结论为各类人员的保健疗养和高血压、神经衰弱等疾病康复提供了科学依据。     

"六经为川,肠胃为海"内涵探析

基于中医学整体观念,运用取象比类的方法,借自然界"川""海"之象进一步阐释"六经"之经与腑的双重含义,以及"肠胃为海"在气血化生、津液输布、糟粕传化、扶正培本方面的内涵.指出"六经"与"肠胃"在生理上彼此依存、病理上相互影响.在现代肠道研究中,肠道消化吸收营养物质、排泄代谢废物,体现了肠胃为"气血生化之海""津液输布之海""糟粕传化之海".肠道菌群促进肠黏膜免疫系统的发育并参与调节机体免疫,体现了肠胃为"扶正培本之海".肠神经系统与内分泌系统通过脑-肠轴的双向调控,如同六经与肠胃之间的海川循环,彼此依存、生生不息.通过探析"六经为川,肠胃为海"在肠道各功能网络中的内涵,揭示象思维在中西医整合医学发展中的重要作用,为挖掘经典及科研创新开辟思路.     

冰敷对不同血脂水平高热大鼠降温效果的实验研究

目的探索冰敷对不同血脂水平高热大鼠降温效果的影响,为不同血脂水平的高热患者实施冷疗提供参考。方法将同一批大鼠随机分为高脂组和对照组,每组10只。高脂组采用高脂饲料饲养,对照组采用普通饲料饲养。饲养3周后采用20%干酵母混悬液将其致热,致热成功后将大鼠麻醉,再使用10mL清水冰袋对其颈部和腋下冰敷30min。冰敷结束0、15、30、45、60、75、90、120、180、240、300、360min监测两组大鼠体温。体温观察结束采集两组大鼠血液检测血脂水平。结果两组大鼠血清总胆固醇和低密度脂蛋白比较,差异有统计学意义(均P<0.01)。冰敷结束45min内高脂组体温显著高于对照组(P<0.05,P<0.01)。结论使用高脂饲料喂养大鼠可在短期内改变血脂状况。血脂水平对降温效果有一定影响,血脂水平高者降温效果差。冰敷过程中针对血脂水平高者应适当增加冰袋或延长冰敷时间,以达到更好的降温效果。     

Producing desired ice faces

The ability to prepare single-crystal faces has become central to developing and testing models for chemistry at interfaces, spectacularly demonstrated by heterogeneous catalysis and nanoscience. This ability has been hampered for hexagonal ice, I_h––a fundamental hydrogen-bonded surface––due to two characteristics of ice: ice does not readily cleave along a crystal lattice plane and properties of ice grown on a substrate can differ significantly from those of neat ice. This work describes laboratory-based methods both to determine the I_h crystal lattice orientation relative to a surface and to use that orientation to prepare any desired face. The work builds on previous results attaining nearly 100% yield of high-quality, single-crystal boules. With these methods, researchers can prepare authentic, single-crystal ice surfaces for numerous studies including uptake measurements, surface reactivity, and catalytic activity of this ubiquitous, fundamental solid.Studies of model, single-crystal surfaces have revolutionized understanding of a vast array of heterogeneous catalysts and nanoparticles ranging from pure metals to alloys to semiconductors. Applying the single-crystal surface strategy to ice––arguably one of the most fundamental and ubiquitous hydrogen-bonded interfaces––has been limited due to challenges associated with surface generation. As a result, questions about molecular-level dynamics, surface binding site patterns, and the molecular-level structure remain unanswered (1). Several strategies have been adopted for studying ice: (i) Depositing solid water on a metal or ionic substrate that matches the oxygen lattice (2, 3). However, ice on a substrate often has distinctly different properties from those of neat ice; indeed, such ice can even be hydrophobic (4, 5)! (ii) Uptake measurements often use a Knudsen cell with vapor-deposited ice on a substrate (6) or compacted, finely divided, artificial snow (7) to arrive at a molecular-level picture for gas–particle interaction despite the irregular, highly variable surfaces used. (iii) Small crystallites can be well characterized but, as highlighted by Libbrecht and Rickerby (8), results can be clouded by competition from nearby crystallites; small faces compete with adjacent faces. In addition, crystallites are perturbed by the supporting surface. It is therefore desirable to prepare macroscopic samples with known faces.Interactions at ice surfaces have a particularly profound effect on climate. For example, correlational studies suggest that rain formation depends on ice particles in clouds (9), but not all ice-containing clouds yield rain. It is thought that variation in supersaturation and the mechanism for gathering water molecules by ice particles profoundly affects precipitation. Discrepancies between experiment and theory are often rationalized as a result of irregular shapes, inelastic scattering, or differing binding sites leaving large uncertainties for climate models (10). More reproducible, well-characterized surfaces of I_h––the most stable form of ice at ambient pressure––are needed to bring clarity.Ice is unusual in that the macroscopic sample does not reveal the crystal lattice orientation. Neighboring grain lattice orientation is a critical issue in the ice-core and glaciology communities (11). Hence, previous work (12–14) focused on determining grain orientation with respect to the grain boundary. The most quantitative of these are the two methods of Matsuda (12). The first uses etch pits measuring lengths inside the pit. Large uncertainties in length measurements result in large uncertainties in lattice axis orientation angles; this is not a major issue for grain growth studies but is a serious problem for generating targeted faces. The second method measures only the azimuths, thus incompletely determining orientation. Both methods break down if the optic axis is near-parallel to the surface, and neither provides the tools required to accurately orient a macroscopic sample to generate a targeted face. Lattice orientation could be determined with X-ray methods (15, 16) provided such determination includes a connection to the macroscopic sample. For wide-spread use, a laboratory-based method is preferable. This work describes two methods to fill this important need. The first uses pit perimeter ratio measurements; because the perimeter is sharp, accuracy is greatly improved. The second method locates the optic axis via cross-polarizers (11, 17), then precisely determines the hexagonal orientation via etching. Closed-form, analytical formulas are derived relating lattice orientation to the macroscopic sample. These orientation formulas feed into rotation matrices generating additional analytical formulas enabling precise cutting of any targeted face. The result is illustrated by cutting each of the three major ice faces. These techniques provide researchers with the tools needed to prepare neat ice surfaces.This work specifically describes face preparation from cylindrical boules (18); however, the method is easily adapted to any macroscopic, single-crystal geometry. Due to nearly equal energy faces, ice takes on the shape of the confining container. The near-energy match is demonstrated by growth in the modified Bridgeman apparatus (19). Nucleation occurs on a polycrystalline seed; single-crystal growth is achieved due to competitive growth among the multiple ice–water interfaces (18). Careful thermal management maintains near-equilibrium conditions yielding a large single crystal, but the crystal orientation is not a priori known. [Note: ice seeded by a floating crystal tends to have the optic axis perpendicular to the growth direction but single-crystal yield is low, ~10% (20).] Close energy match among the faces also means that ice does not readily cleave along any lattice plane (21). Thus, successful face preparation for any ice sample begins with characterization of the lattice orientation.