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Shuram-wonoka carbon isotope excursion:Ediacaran revolution in the world ocean's meridional overturning circulation

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(<30°-35°) atmospheric 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

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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

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Targeting Epac2 and GluA3-containing AMPARs:a novel therapeutic strategy for Alzheimer's disease

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Neural Regeneration Research 2025年第11期20卷 3223-3224页

作者： Tong Zhang Martina schmidt Department of Molecular Pharmacology Groningen Research Institute of PharmacyUniversity of GroningenGroningenThe Netherlands School of Pharmacy Tianjin Medical UniversityTianjinChina

Alzheimer's disease(AD)is a neurodegenerative disease that manifests progressive decline in memory and *** the early stage of AD,memory retrieval is impaired preceding memory acquisition and consolidation(Roy et al.,2016).Prior to the onset of symptoms,pathological amyloid-β(Aβ)plagues and tau protein tangles accumulate in extracellular and intracellular spaces,respectively,leading to *** these hallmark pathologies,Aβ is proposed to be the primary etiology by triggering a cascade of pathogenic events,including neuroinflammation,oxidative stress,tau hyperphosphorylation,synaptic/neuronal dysfunction,and neuronal death(Zhang et al.,2023b).

关键词： Alzheimer impaired Aβ

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Comparison between the quality and function of sperm after semen processing with two different methods

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Asian Journal of Andrology 2001年第2期3卷 125-130页

作者： M.E.Hammadeh P.M.Zavos P.Rosenbaum w.schmidt Dept. of Obs/Gyn University of Saarland 66421 Homburg/Saar GermanyAndrology Insitute of America and Kentucky Center for Reproductive Medicine & IVF Lexington KY USADept. of Obs/Gyn University of Saarland 66421 Homburg/Saar GermanyDept. of Obs/Gyn University of Saarland 66421 Homburg/Saar Germany

Aim: To compare the recovery rate of morphologically normal and chromatin condensed spermatozoa from native se-men samples using the SpermPrep^(TM) filtration columns and Percoll gradient centrifugation and to determine the influenceof the two processing techniques on fertilization and pregnancy rates in an IVF-ET program. Methods: Sixteen se-men samples obtained from patient's husband were included in this study. Each was divided into two aliquots. The firstaliquot was processed with SpermPrep^(TM) filtration columns and the second, Percoll gradient centrifugation. Smears weremade before and after semen processing with both methods for the evaluation of chromatin condensation (chromomycineCMA3) as well as morphology (strict criteria) of spermatozoa. One hundred and seventy oocytes were retrieved fromthe patients and the oocytes from each patient were subdivided into two sets : one set was inseminated using spermatozoaprocessed with SpermPrep^(TM) and the other inseminated after semen processing with Percoll gradient centrifugation. Re-sults: The Percoll method yielded a significantly higher percentage of chromatin condensed (90.8 ±6.5% vs 82.3±8.8%, P = 0.017) and morphologically normal spermatozoa (12.9±7.4% vs 6.9±4.8%, P =0.001) in com-parison to SpermPrep^(TM). whereas, sperm count recovery rate was significantly higher after the use of SpermPrep^(TM) thanafter the Percoll gradient centrifugation. The fertilization rate was similar between the two methods. Conclusion:Semen processing with Percoll should be recommended for intracytoplasmic sperm injection as the natural selection isbypassed and the SpermPrep^(TM) technique could be recommended for IVF and IUI programs as the sperm concentrationplays a more significant role in these procedures.

关键词： sperm semen processing spermPrep^(TM) percoll gradient centrifugation IVF

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Integrating impedance-based growth-rate monitoring into a microfluidic cell culture platform for live-cell microscopy

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Microsystems & Nanoengineering 2018年第1期4卷 325-336页

作者： Ketki Chawla Sebastian C.Bürgel Gregor w.schmidt Hans-Michael Kaltenbach Fabian Rudolf Olivier Frey Andreas Hierlemann ETH Zurich Department of Biosystems Science and EngineeringBio Engineering LaboratoryBaselSwitzerland ETH Zurich Department of Biosystems Science and EngineeringComputational Systems Biology GroupBaselSwitzerland

Growth rate is a widely studied parameter for various cell-based biological *** rates of cell populations can be monitored in chemostats and micro-chemostats,where nutrients are continuously ***,we present an integrated microfluidic platform that enables long-term culturing of non-adherent cells as well as parallel and mutually independent continuous monitoring of(i)growth rates of cells by means of impedance measurements and of(ii)specific other cellular events by means of high-resolution optical or fluorescence *** colonies were grown in a monolayer under culturing pads,which enabled high-resolution microscopy,as all cells were in the same focal *** cell growth and division,cells leaving the culturing area passed over a pair of electrodes and were counted through impedance *** impedance data could then be used to directly determine the growth rates of the cells in the culturing *** integration of multiple culturing chambers with sensing electrodes enabled multiplexed long-term monitoring of growth rates of different yeast strains in *** a demonstration,we modulated the growth rates of engineered yeast strains using *** results indicated that impedance measurements provide a label-free readout method to continuously monitor the changes in the growth rates of the cells without compromising high-resolution optical imaging of single cells.

关键词： impedance continuously culture

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A novel method for clustering cellular data to improve classification

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Neural Regeneration Research 2025年第9期20卷 2697-2705页

作者： Diek w.wheeler Giorgio A.Ascoli Center for Neural Informatics Structures&PlasticityKrasnow Institute for Advanced Study Bioengineering Department Volgenau School of Engineering George Mason University FairfaxVAUSA

Many fields,such as neuroscience,are experiencing the vast prolife ration of cellular data,underscoring the need fo r organizing and interpreting large datasets.A popular approach partitions data into manageable subsets via hierarchical clustering,but objective methods to determine the appropriate classification granularity are *** recently introduced a technique to systematically identify when to stop subdividing clusters based on the fundamental principle that cells must differ more between than within *** we present the corresponding protocol to classify cellular datasets by combining datadriven unsupervised hierarchical clustering with statistical *** general-purpose functions are applicable to any cellular dataset that can be organized as two-dimensional matrices of numerical values,including molecula r,physiological,and anatomical *** demonstrate the protocol using cellular data from the Janelia MouseLight project to chara cterize morphological aspects of neurons.

关键词： cellular data clustering dendrogram data classification Levene's one-tailed statistical test unsupervised hierarchical clustering

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Genistein:a possible solution for the treatment of Alzheimer’s disease

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Neural Regeneration Research 2025年第10期20卷 2903-2905页

作者： Karolina Pierzynowska Bartosz Karaszewski Grzegorz węgrzyn Department of Molecular Biology University of GdanskGdanskPoland Gdansk Polandand Department of Adult NeurologyFaculty of MedicineMedical University of GdanskGdanskPoland

Neurodegenerative diseases are defined as disorders resulting from the slow and progressive loss of function and eventual death of neural cells that result from the primary pathology of nervous *** can lead to severe nervous system dysfunction,eventually affecting multiple organs and *** hundred neurodegenerative diseases have been described,and owing to their prevalence,severity.

关键词： organs Alzheimer death

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Performance-based concept on seismic evaluation of existing bridges

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Earthquake Engineering and Engineering Vibration 2009年第1期8卷 127-135页

作者： Yu-Chi Sung wen-I Liaoi w.phillip Yen Department of Civil Engineering Taipei University of Technology Taipei 10608 Chinese Taipei Office of lnfrastructure R＆D Federal Highway Administration 6300 Georgetown Pike McLean VA 20121 USA

Conventional seismic evaluation of existing bridges explores the ability of a bridge to survive under significant earthquake excitations. This approach has several major drawbacks, such as only a single structural performance of near collapse is considered, and the simplified approach of adopting strength-based concept to indirectly estimate the nonlinear behavior of a structure lacks accuracy. As a result, performance-based concepts that include a wider variety of structural performance states of a given bridge excited by different levels of earthquake intensity is needed by the engineering community. This paper introduces an improved process for the seismic evaluation of existing bridges. The relationship between the overall structural performance and earthquakes with varying levels of peak ground acceleration （PGA） can successfully be linked. A universal perspective on the seismic evaluation of bridges over their entire life-cycle can be easily obtained to investigate multiple performance objectives. The accuracy of the proposed method, based on pushover analysis, is proven in a case study that compares the results from the proposed procedure with additional nonlinear time history analyses.

关键词： pushover analysis plastic hinge seismic capacity seismic demand performance-based concepts

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Glia-to-neuron reprogramming to the rescue?

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Neural Regeneration Research 2025年第5期20卷 1395-1396页

作者： Jack w.Hickmott Cindi M.Morshead Department of Surgery University of TorontoTorontoONCanada Donnelly Centre for Cellular and Biomolecular Research TorontoONCanada Institute of Biomedical Engineering University of TorontoTorontoONCanada The KITE Research Institute Toronto Rehabilitation InstituteUniversity Health NetworkTorontoONCanada

Over the last two decades,the dogma that cell fate is immutable has been increasingly challenged,with important implications for regenerative *** brea kth rough discovery that induced pluripotent stem cells could be generated from adult mouse fibroblasts is powerful proof that cell fate can be *** exciting extension of the discovery of cell fate impermanence is the direct cellular reprogram ming hypothesis-that terminally differentiated cells can be reprogrammed into other adult cell fates without first passing through a stem cell state.

关键词： programming passing proof

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第六章液氧泵

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导弹与航天运载技术(中英文) 1979年第3期 61-78页

作者： Harold w.schmidt

最普遍用来抽运液氧或气氧的涡轮泵是离心涡轮泵,这种涡轮泵几乎完全用于火箭发动机系统。离心泵还广泛用作地面抽运液氧的设备和作为大流量气氧压气机,凡是需要达到极高

关键词：液氧泵涡轮泵参考文献气蚀低温泵透平泵化工用泵空蚀轮(机械元件) 诱导轮密封件

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