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Geoscience Frontiers 2018年第2期9卷 391-402页

作者： George e.Williams phillip W.Schmidt Department of earth Sciences University of Adelaide Magneticearth

The late ediacaran Shuram-Wonoka excursion, with δ^(13)C_(carb) values as low as-12‰(PDB) in marineshelf deposits and spanning up to 10 Myr, is the deepest and most protracted δ^(13)C_(carb) negative anomaly recognised in earth history. The excursion formed on at least four continents in low(≤32°) palaeolatitudes, and in China is associated with a major phosphogenic event. Global and intrabasinal correlation, magnetostratigraphy, isotope conglomerate tests and further geochemical data are consistent with a primary or syn-depositional origin for the excursion. Continental-margin phosphorites are generated by oceanic upwelling driven by surface winds, and δ^(13)C_(carb) negative anomalies are explicable by oceanic upwelling of 13 C-depleted deep oceanic waters, arguing that a feature common to these exceptional ediacaran events was unprecedented perturbation of the world ocean. These events occurred during the transition from an alien Proterozoic world marked by low-palaeolatitude glaciation near sea level and strong seasonality to the familiar Phanerozoic earth with circum-polar glaciation and temperate climate, suggesting that the Shuram-Wonoka excursion is related to this profound change in earth's climate system. Of various hypotheses for Proterozoic low-palaeolatitude glaciation, only the high obliquity(>54°) hypothesis, which posits secular decrease in obliquity to near the present-day value(23.5°) during the ediacaran, predicts an unparalleled revolution in the ediacaran world ocean. The obliquity controls the sense of the world ocean's meridional overturning circulation, which today is driven by the sinking of cold, dense water at the poles and upwelling driven by zonal surface *** the decreasing obliquity passed the critical value of 54° during the ediacaran the meridional temperature gradient reversed, with the equator becoming warmer than the poles and Hadley lowlatitude(eric zonal circulation reversing. This reversal of the temperat

关键词： ediacaran Shuram-Wonoka carbon isotope excursion Oceanic meridional circulation Atmospheric circulation Proterozoic paleoclimate Obliquity of the ecliptic

Intracellular Transport of Plant Viruses： Finding the Door out of the Cell

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Molecular Plant 2011年第5期4卷 813-831页

作者： James e. Schoelz phillip A. Harries Richard S. Nelson Division of Plant Sciences University of Missouri Columbia MO 65211 USA Department of Biology Pittsburg State University Pittsburg KS 66762 USA Plant Biology Division The Samuel Roberts Noble Foundation Inc. Ardmore OK 73401 USA

Plant viruses are a class of plant pathogens that specialize in movement from cell to cell. As part of their arsenal for infection of plants, every virus encodes a movement protein （MP）, a protein dedicated to enlarging the pore size of plasmodesmata （PD） and actively transporting the viral nucleic acid into the adjacent cell. As our knowledge of intercellular transport has increased, it has become apparent that viruses must also use an active mechanism to target the virus from their site of replication within the cell to the PD. Just as viruses are too large to fit through an unmodified plasmodesma, they are also too large to be freely diffused through the cytoplasm of the cell. evidence has accumulated now for the involvement of other categories of viral proteins in intracellular movement in addition to the MP, including viral proteins originally associated with replication or gene expression. In this review, we will discuss the strategies that viruses use for intracellular movement from the replication site to the PD, in particular focusing on the role of host membranes for intracellular transport and the coordinated interactions between virus proteins within cells that are necessary for successful virus spread.

关键词： Macromolecular trafficking membrane biology membrane proteins movement proteins plasmodesmata plant-virus interactions.

Molecular dynamics study of water diffusion in an amphiphilic block copolymer with large difference in the blocks＇ glass transition temperatures

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Frontiers of Chemical Science and engineering 2017年第3期11卷 440-447页

作者： Yang Zhou phillip Choi Department of Chemical and Materials engineering University of Alberta Edmonton Edmonton AB T6G 1H9 Canada

Isothermal-isobaric molecular dynamics simu- lation was used to study the diffusion mechanism of water in polyurethane-block-poly（N-isopropyl acrylamide）（PU- block-PNIPAm） with a hydrophobic PU/hydrophilic PNIPAm mass ratio of 1.4 to 1 at 298 K and 450 K. Here, the experimental glass transition temperature （Tg） of PU is 243 K while that of PNIPAm is 383 K. Different amounts of water up to 15 wt-% were added to PU-block- PNIPAm. We were able to reproduce the specific volumes and glass transition temperatures （250 K and 390 K） of PU- block-PNIPAm. The computed self-diffusion coefficient of water increased exponentially with increasing water concentration at both temperatures （i.e., following the free volume model of Fujita）. It suggested that water diffusion in PU-block-PNIPAm depends only on its fractional free volume despite the free volume inhomo- geneity. It is noted that at 298 K, PU is rubbery while PNIPAm is glassy. Regardless of temperature, radial distribution functions showed that water formed clusters with sizes in the range of 0.2-0.4 nm in PU-block- PNIPAm. At low water concentrations, more clusters were found in the PU domain but at high water concentrations, more in the PNIPAm domain. It is believed that water molecules diffuse as clusters rather than as individual molecules.

关键词： molecular dynamics simulation amphiphilic block copolymer free volume water diffusivity fujita model

Strongly seasonal Proterozoic glacial climate in low palaeolatitudes:Radically different climate system on the pre-ediacaran earth

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Geoscience Frontiers 2016年第4期7卷 555-571页

作者： George e.Williams phillip W.Schmidt Grant M.Young Department of earth Sciences University of AdelaideSA 5005Australia CSIRO Mineral Resources Flagship PO Box 52North RydeNSW 16FOAustralia Department of earth Sciences University of Western OntarioLondonOntario N6A 5B7Canada

Proterozoic （pre-ediacaran） glaciations occurred under strongly seasonal climates near sea level in low palaeolatitudes. Metre-scale primary sand wedges in Cryogenian periglacial deposits are identical to those actively forming, through the infilling of seasonal （winter） thermal contraction-cracks in perma- frost by windblown sand, in present-day polar regions with a mean monthly air temperature range of 40 ~C and mean annual air temperatures of -20 ~C or lower. Varve-like rhythmites with dropstones in Proterozoic glacial successions are consistent with an active seasonal freeze-thaw cycle. The seasonal （annual） oscillation of sea level recorded by tidal rhythmites in Cryogenian glacial successions indicates a significant seasonal cycle and extensive open seas. Palaeomagnetic data determined directly for Prote- rozoic glacial deposits and closely associated rocks indicate low palaeolatitudes： Cryogenian deposits in South Australia accumulated at 〈10% most other Cryogenian deposits at 〈20~ and Palaeoproterozoic deposits at 〈15~ palaeolatitude. Palaeomagnetic data imply that the Proterozoic geomagnetic field approximated a geocentric axial dipole, hence palaeolatitudes represent geographic latitudes. The Cry- ogenian glacial environment included glacier-flee, continental permafrost regions with ground frozen on a kyr time-scale, aeolian sand-sheets, extensive and long-lived open seas, and an active hydrological cycle. This palaeoenvironment confiicts with the ＇snowball earth＇ and ＇slushball earth＇ hypotheses, which cannot accommodate large seasonal changes of temperature near the equator. Consequently, their proponents have attempted to refute the evidence for strong seasonality by introducing Popperian ＇auxiliary assumptions＇. However, non-actualistic arguments that the Cryogenian sand wedges indicate diurnal or weakly seasonal temperature changes are based on misunderstandings of periglacial pro- cesses. Modelling of a strongly seasonal climate for a frozen-over ear

关键词： Proterozoic Glaciation Periglacial structures Varves Paleoclimate Paleomagetism

Increased Drying Rate Lowers the Critical Water Content for Survival in embryonic Axes of english Oak (Quercus robur L.) Seeds

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Journal of Integrative Plant Biology 2011年第4期53卷 270-280页

作者： Tobias M.Ntuli William e.Finch-savage Patricia Berjak Norman W.Pammenter Plant Germplasm Conservation Research School of Biological and Conservation SciencesUniversity of KwaZulu-NatalWestville CampusPrivate Bag X54001Durban 4000South Africa Department of Life and Consumer Sciences University of South AfricaPrivate Bag X6Florida 1710JohannesburgSouth Africa Warwick HRI Warwick UniversityWellesbourneWarwick CV35 9EFUK Plant Germplasm Conservation Research School of Biological and Conservation SciencesUniversity of KwaZulu-NatalWestville

The potential to cryopreserve embryonic axes of desiccation-sensitive（recalcitrant） seeds is limited by damage during the desiccation necessary for low temperature survival,but the basis of this injury and how to reduce it is not well *** effects of drying rate on the viability,respiratory metabolism and free radical-mediated processes were therefore investigated during dehydration of Quercus robur L embryonic ***,assessed by evidence of germination and tetrazolium staining,showed a sharp decline at 0.27 and 0.8 g/g during rapid（〈12 h） or slow（3d） dehydration,*** dehydration therefore lowered the critical water content for *** any given water content rapid dehydration was associated with higher activities of the free radical processing enzymes,superoxide dismutase,catalase and glutathione reductase and lower levels of hydroperoxide and membrane *** dehydration was also associated with lower malate dehydrogenase activity,and a reduced decline in phosphofructokinase activity and in levels of the oxidized form of nicotinamide *** may have contributed to increased damage during slow dehydration,since viability declined even in hydrated storage after 3 *** results presented are consistent with rapid dehydration reducing the accumulation of damage resulting from desiccation induced aqueous-based deleterious reactions.

关键词： Quercus robur L Seeds Figure NADH

Development of a Long-Term Operational Optimization Model for a Building energy System Supplied by a Geothermal Field

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Journal of Thermal Science 2022年第5期31卷 1293-1301页

作者： KÜMPeL Alexander STOFFeL phillip MÜLLeR Dirk RWTH Aachen University E.ON Energy Research CenterInstitute for Energy Efficient Buildings and Indoor ClimateAachen 52074Germany

In order to reduce energy consumption and CO_(2) emissions in the building sector, more and more renewable energy sources are integrated into energy systems. especially geothermal fields combined with heat pumps are able to supply buildings with heat and cold at low carbon emissions. However, using geothermal fields as heat and cold source influences the ground temperature. Consequently, the ground temperature can change dramatically over a building’s lifetime, leading to less efficient operation of the energy system. Therefore, a sustainable operation is required to ensure the long-term efficiency of geothermal fields. In this paper, we develop an optimization model to derive operating strategies for an efficient long-term operation of a building energy system coupled to a geothermal field. The investigated energy system is the main building of the *** energy Research Center in Aachen, Germany, which includes a heat pump, two boilers, a combined heat, and power unit, a glycol cooler, and a geothermal field with 41 probes. For each component, we develop energy-based sub-models, which are connected to form the overall system. The geothermal field is modeled by using a g-functions approach as well as a simplified resistance-capacitance approach. To achieve short computing times and realize an optimization horizon of several years, the optimization problem is formulated as mixed-integer linear programming(MILP). The developed model is optimized regarding two different objectives: the minimization of energy costs and the minimization of long-term temperature changes in the ground. Conclusions for an efficient and sustainable operation of the field, especially for the cooling supply, can be derived from the optimization results. It is shown that a state of equilibrium should be aimed to achieve an energy-efficient operation, in which the temperature of the field is close to the initial ground temperature.

关键词： geothermal energy building energy systems operational optimization long-term operation

Cloud-Based Optimal Control of Individual Borehole Heat exchangers in a Geothermal Field

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Journal of Thermal Science 2022年第5期31卷 1253-1265页

作者： STOFFeL phillip KÜMPeL Alexander MÜLLeR Dirk RWTH Aachen University E.ON Energy Research CenterInstitute for Energy Efficient Buildings and Indoor Climate52074 AachenGermany

Integrating renewable energy sources is a crucial component in reducing CO_(2) emissions in the building sector. In particular, shallow geothermal energy is expected to play a significant role in the regenerative energy supply of buildings. An effective control strategy for the geothermal field is crucial to reduce the overall energy consumption. This paper analyzes the benefits of controlling an existing field’s individual borehole heat exchangers(BHe) using nonlinear model predictive control(NMPC) and moving horizon estimation. The considered geothermal field consists of 41 BHes and is used for heating and cooling. each BHe is equipped with temperature sensors for in-and outflow and has individually controllable valves, while a central hydraulic pump feeds all BHes. The sensor measurements are accessed through a cloud platform, enabling also set point writing for the pump speed and the valve positions. To control the BHes individually, we propose a two-stage process. In the calibration stage, a moving horizon estimator estimates the actual borehole and ground temperatures for each BHe. In the second stage, first, a nonlinear model predictive controller optimizes the number of active BHes necessary to meet the buildings’ energy demand. With the estimated ground temperatures as a basis, it is determined which BHes shall be(de)-activated. The active BHes are fed with a fixed volume flow of 24 L/min to ensure turbulent heat transfer. To reduce the power usage of the pumps, an optimal control problem based on a simple hydraulic model of the geothermal field is used. The methodology is analyzed through simulations first and then validated experimentally. The results show that half or more of the BHes could be deactivated most of the time, leading to 67% savings in electricity consumption by the hydraulic pump. The experimental validation confirms the high energy saving potential of the proposed methodology, reducing the consumption of electrical energy by 71%. Additiona

关键词： geothermal energy moving horizon estimation model predictive control operation optimization optimal control

Inorganic nanoparticles and the microbiome

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Nano Research 2018年第10期11卷 4936-4954页

作者： Kunyu Qiu phillip G. Durham Aaron C. Anselmo Division of Pharmacoengineering and Molecular Pharmaceutics Eshelman School of Pharmacy University of North Carolina atChapel Hill Chapel Hill NC27599 USA

Routine exposure to inorganic nanoparticles （NPs） that are incorporated into consumer products such as foods/drinks, packaging materials, pharmaceuticals, and personal care products （e.g. cosmetics, sunscreens, shampoos） occurs on a daily basis. The standard everyday use of these products facilitates interactions between the incorporated inorganic NPs, mammalian tissues （e.g. skin, gastrointestinal tract, oral cavity）, and the community of microbes that resides on these tissues. Changes to the microbiome have been linked to the initiation/ progression of many diseases and there is a growing interest focused on understanding how inorganic NPs can initiate these changes. As these mechanisms are revealed and defined, it may be possible to rationally design microbiota- modulating therapies based on inorganic NPs. In this article, we will：（i） provide a background on inorganic NPs that are commonly found in consumer products such as those that incorporate titanium, zinc, silver, silica, or iron, （ii） discuss how NP properties, microbiota composition, and the physiological microenvironment can mediate the effects that inorganic NPs have on the microbiota, and （iii） highlight opportunities for inorganic NP therapies that are designed to interact with, and navigate, the microbiome.

关键词： inorganic nanoparticles microbiota microbiome bacteria metals

hiPSCs: Reprogramming towards cell-based therapies

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Open Journal of Regenerative Medicine 2013年第3期2卷 61-73页

作者： phillip e. Woolwine 不详

Stem cell therapies show great potential for use in regenerative medicine, though advancements in safe stem cell technology need to be realized. Human induced pluripotent stem cells (hiPSCs) hold an advantage over other stem cell types for use in cell-based therapies due to their potential as an unlimited source of rejuvenated and immunocompatible SCs which do not elicit the ethical and moral debates associated with the destruction of human embryos. Towards realization of this potential this review focuses on the recent progress in DNA-and xeno-free reprogramming methods, particularly small molecule methods, as well as addresses some of the latest insights on donor cell gene expression, telomere dynamics, and epigenetic aberrations that are a potential barrier to successful widespread clinical applications.

关键词： iPSC Reprogramming Small Molecules Oct4 epigenetics Regenerative Medicine Clinical Regulations