检索结果-南通市图书馆

Assessing Possibilities and Limitations for Biomarker Analyses on Outcrop Samples:A Case Study on Carbonates of the Shibantan Member (Ediacaran Period, Dengying Formation, South China)

引用

Acta Geologica Sinica(English Edition) 2014年第6期88卷 1696-1704页

作者： jan-peter duda Volker THIEL Joachim REITNER Martin BLUMENBERG Geoscience Centre Geobiology Group Georg-August-University GttingenGoldschmidtstr.337077 Gttingen Germany Federal Institute for Geosciences and Natural Resources (BGR) Stilleweg 2 30655 Hannover Germany

The Shibantan Member（Dengying Formation, South China） represents one of only two carbonate settings with Ediacara-type organisms and offers a rare opportunity to study the biogeochemistry of these ecosystems. To evaluate possibilities and limitations for future biomarker studies on fossil-bearing outcrop samples of the Shibantan Member, we analysed the spatial distribution of hydrocarbons in extractable organic matter（i.e. bitumen） on a millimetre scale. Our study demonstrates that the sample and most likely also other rocks from the same setting are contaminated with petroleum-derived compounds that bear the potential for erroneous interpretations in palaeo-reconstructions. The contamination was revealed by distribution patterns and amounts of extractable n-alkanes and acyclic isoprenoids. The contamination is linked to the external weathering surfaces but also to cracks within the rock, and the extent most likely depends on concentration gradients between these contamination sources. Here we show that contamination can successfully be distinguished from syngenetic signals obtained from non-extractable organic matter（i.e. kerogen） using catalytic hydropyrolysis（Hy Py）. However, we observed that decalcification is necessary to achieve sufficient yields of kerogen-bound hydrocarbons and to avoid artificial alteration of the biomarker signals due to matrix effects.

关键词： Ediacaran biomarkers contamination syngeneity slice-experiments catalytic hydropyrolysis(HyPy)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Individual effect of Y and Nd on the microstructure formation of Mg-Y-Nd alloys processed by severe plastic deformation and their effect on the subsequent mechanical and corrosion properties

引用

Journal of Magnesium and Alloys 2023年第2期11卷 509-521页

作者： Maria Zemkova peter Minarik jan Dittrich jan Bohlen Robert Kral Charles University Department of Physics of MaterialsKe Karlovu 512116PragueCzechia University of Zilina Research CentreUniverzitna8215/1Zilina01026Slovakia Institute of Material and Process Design Helmholtz-Zentrum Hereon21502GeesthachtGermany

This work investigated the effect of sole yttrium and neodymium alloying on the microstructure formation during severe plastic deformation by equal channel angular pressing(ECAP) and an impact on the mechanical strength and corrosion resistance of binary Mg-3Y and Mg-3Nd *** results are compared with a ternary Mg-4Y-3Nd alloy,which represents a simplified version of the commercially successful WE43 *** extensive study comprises a thorough microstructural analysis performed by scanning and transmission electron microscopy,including electron backscatter diffraction and texture analysis performed by X-ray *** is shown that the presence of Nd primarily caused precipitation during the processing of the Mg-3Nd alloy,while Y remained dissolved in the magnesium matrix in the Mg-3Y *** difference resulted in a significantly smaller average grain size in the Mg-3Y alloy(~0.77 nm) than in the Mg-3Nd alloy(~1.3 μm) after the final step of the processing and formation of a slightly different ***,the composition and the processing affected the mechanical and corrosion properties of the investigated materials,measured by compression deformation tests,microhardness measurement,and electrochemical impedance *** study shows that the ECAP-processed W3 sample exhibits a surprisingly good combination of ultrafine-grain structure,weak crystallographic texture,high strength,and high corrosion resistance compared with the other investigated *** attributes make this material very interesting for utilisation in the industry and/or medicine.

关键词： Magnesium Rare earth elements Microstructure Texture Mechanical strength Corrosion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Dynamic Actin Controls Polarity Induction de novo in Protoplasts

引用

Journal of Integrative Plant Biology 2013年第2期55卷 142-159页

作者： Beatrix Zaban jan Maisch peter Nick Botanical Institute Molecular Cell Biology Karlsruhe Institute of Technology

Cell polarity and axes are central for plant morphogenesis. To study how polarity and axes are induced de novo, we investigated protoplasts of tobacco Nicotiana tabacum cv. BY-2 expressing fluorescently- tagged cytoskeletal markers. We standardized the system to such a degree that we were able to generate quantitative data on the temporal patterns of regeneration stages. The synthesis of a new cell wall marks the transition to the first stage of regeneration, and proceeds after a long preparatory phase within a few minutes. During this preparatory phase, the nucleus migrates actively, and cytoplasmic strands remodel vigorously. We probed this system for the effect of anti-cytoskeletal compounds, inducible bundling of actin, RGD-peptides, and temperature. Suppression of actin dynamics at an early stage leads to aberrant tripolar cells, whereas suppression of microtubule dynamics produces aberrant sausage- like cells with asymmetric cell walls. We integrated these data into a model, where the microtubular cytoskeleton conveys positional information between the nucleus and the membrane controlling the release or activation of components required for cell wall synthesis. Cell wall formation is followed by the induction of a new cell pole requiring dynamic actin filaments, and the new cell axis is manifested as elongation growth perpendicular to the orientation of the aligned cortical microtubules.

关键词： Actin axis formation microtubules polarity induction tobacco BY-2 protoplasts.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Break of symmetry in regenerating tobacco protoplasts is independent of nuclear positioning

引用

Journal of Integrative Plant Biology 2016年第9期58卷 799-812页

作者： Linda Brochhausen jan Maisch peter Nick Molecular Cell Biology Botanical Institute Karlsruhe Institute of Technology Katserstr. 2 D-76133 Karlsruhe Germany

Nuclear migration and positioning are crucial for the morphogenesis of plant cells. We addressed the potential role of nuclear positioning for polarity induction using an experimental system based on regenerating protoplasts, where the induction of a cell axis de novo can be followed by quantification of specific regeneration stages. Using overexpression of fluorescently tagged extranuclear （perinu- clear actin basket, kinesins with a calponin homology domain （KCH）） as well as intranuclear （histone H2B） factors of nuclear positioning and time-lapse series of the early stages of regeneration, we found that nuclear position is no prerequi- site for polarity formation. However, polarity formation and nuclear migration were both modulated in the transgenic lines, indicating that both phenomena depend on factors affecting cytoskeletal tensegrity and chromatin structure. We integrated these findings into a model where retrograde signals are required for polarity induction. These signals travel via the cytoskeleton from the nucleus toward targets at the plasma membrane.

关键词： Axis formation cytoskeleton nuclear migration polarity induction tobacco BY-2 protoplast

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Running Temperature and Mechanical Stability of Grease as Maintenance Parameters of Railway Bearings

引用

International Journal of Automation and computing 2010年第2期7卷 160-166页

作者： jan Lundberg Aditya Parida peter Sderholm Division of Operation and Maintenance Engineering Lule University of Technology

Spherical roller bearings in railway car wheels are critical components whose failure may have catastrophic consequences. The present study aims to analyse the mechanical stability of greases and temperature of bearings as indicators for condition-based bearing maintenance. The performed case study includes nine fully-formulated commercial greases examined in the wheel bearings of five ore cars operated in northern Scandinavia. The studied ore cars travelled a distance of about 300 000 km during a period of three years. Small samples of the greases were taken on eight occasions to test their mechanical stability. In addition, the temperatures of the bearings were continuously recorded. After the test period, the wear, electrical damage, and corrosion of the bearings were examined. One of the findings is that the shear stress of the grease at a certain shear velocity （the certain yieldstress （CEY） value） is a good maintenance indicator and is highly dependent on the grease type. The bearing＇s wear, electrical damage and corrosion also depend on the grease type. However, no oxidation of the greases was identified. The paper also outlines a systematic methodology to determine an overall maintenance indicator for railway roller bearings which is based on the field measurements.

关键词： Maintenance mechanical stability railway roller bearings grease lubrication.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Non-compliant and compliant balloons for endovascular rescue therapy of cerebral vasospasm after spontaneous subarachnoid haemorrhage: experiences of a single- centre institution with radiological follow- up of the treated vessel segments

引用

Stroke & Vascular Neurology 2021年第1期6卷 16-24页

作者： Alexander Neumann jan Küchler Claudia Ditz Kara Krajewski jan Leppert peter Schramm Hannes Schacht Neuroradiology University Medical Center Schleswig Holstein Lubeck CampusLubeckGermany Neurosurgery University Medical Center Schleswig Holstein Lubeck CampusLubeckGermany

Background For endovascular rescue therapy(ERT)of cerebral vasospasm(CVS)due to spontaneous subarachnoid haemorrhage(sSAH),non-compliant(NCB)and compliant(CB)balloons are used with both balloon types bearing the risk of vessel injury due to specific mechanical *** severe delayed arterial narrowing after transluminal balloon angioplasty(TBA)for CVS has sporadically been described,valid data concerning incidence and relevance are *** aim was to analyse the radiological follow-up(RFU)of differently TBA-treated arteries(CB or NCB).Methods Twelve patients with utilisation of either NCB or CB for CVS were retrospectively analysed for clinical characteristics,ERT,functional outcome after 3 months and *** with the initial angiogram,we classified delayed arterial narrowing as mild,moderate and severe(60% calibre reduction).Results Twenty-three arteries were treated with CB,seven with *** median first RFU was 11 months after TBA with CB and 10 after *** was performed with catheter angiography in 18 arteries(78%)treated with CB and in five(71%)after NCB;magnetic resonance angiography was acquired in five vessels(22%)treated with CB and in two(29%)after *** arterial narrowing was detected in three arteries(13%)after CB and in one(14%)after *** or severe findings were neither detected after use of CB nor *** We found no relevant delayed arterial narrowing after TBA for CVS after *** previous assumptions that CB provides for more dilatation in segments adjacent to CVS,we observed no disadvantages concerning long-term adverse *** data support TBA as a low-risk treatment option.

关键词： balloon cerebral after

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Perturbation finite element solution for chemo-elastic boundary value problems under chemical equilibrium

引用

Acta Mechanica Sinica 2019年第5期35卷 981-991页

作者： peter L.Bishay jan Sladek Nicholas Fabry Vladimir Sladek Chuanzeng Zhang College of Engineering and Computer Science California State UniversityNorthridgeCAUSA Institute of Construction and Architecture Slovak Academy of SciencesBratislavaSlovakia Department of Civil Engineering University of Siegen57068 SiegenGermany

Modeling the elastic behavior of solids in energy conversion and storage devices such as fuel cells and lithium-ion batteries is usually difficult because of the nonlinear characteristics and the coupled chemo-mechanical behavior of these *** this work,a perturbation finite element(FE)formulation is developed to analyze chemo-elastic boundary value problems(BVPs)under chemical *** perturbation method is applied to the FE equations because of the nonlinearity in the chemical potential expression as a function of solute *** compositional expansion coefficient is used as the perturbation *** the perturbation expansion,a system of partial differential equations for the displacement and dimensionless solute concentration functions is obtained and solved in consecutive *** presence of a numerical solution enables modeling 3D chemo-elastic solids,such as battery electrodes or ionic gels,of any geometric shape with defects of different *** proposed method is tested in several numerical examples such as plates with circular or elliptical holes,and *** numerical examples showed how the shape of the defect can change the distribution of solute concentration around the *** in chemo-elastic solids create sharp peaks in solute concentration around crack tips,and the intensity of these peaks increases as the far field solute concentration decreases.

关键词： Chemical potential Solute concentration Compositional expansion coefficient 2D stationary problem

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ectopic liver: Different manifestations, one solution

引用

World Journal of Gastroenterology 2013年第38期19卷 6485-6489页

作者： Pavel Zonca Lubomir Martinek peter Ihnat jan Fleege Department of Surgery University Hospital Ostrava70852 OstravaCzech Republic Department of Surgical Studies Faculty of MedicineUniversity of Ostrava70300 OstravaCzech Republic MVZ Zentrum für Pathologie und Zytodiagnostik GmbH 50996 KlnGermany

Developmental abnormalities are rare in the *** study presents two case reports of ectopic *** first case was a 31-year-old male with clinical indication for laparoscopic *** identified a perforated appendix and an unknown tumorous lesion in the ligamentum hepato *** patient underwent a laparoscopic appendectomy,intraoperative lavage of the peritoneal cavity,and extirpation of the lesion in the ligamentum hepato *** examination of the excised tumor revealed that it comprised liver tissue with fibrinous *** tumor was completely separate from the liver with no *** was classified as an ectopic *** further therapy was *** second case was a59-year-old male with a tumor on the upper pole of the spleen,incidentally diagnosed in an ultrasound *** biopsy raised suspicion of hepatocellular carcinoma.A positron emission tomography-computed tomography examination revealed accumulation of F-18 fluorodeoxyglucose only in the *** patient underwent a splenectomy with a resection and reconstruction of *** the hepatocellular carcinoma was confirmed,adjuvant therapy(sorafenib)was *** operations and postoperative recoveries were uncomplicated in both *** the low incidence of ectopic liver and rare complications,it is necessary to maintain awareness of this *** potential malignancy risk for ectopic liver tissue is the basis for radical surgical *** for hepatocellular carcinoma in an ectopic liver follows the same guidelines as those followed for treating the"mother"liver.

关键词： Ectopic Liver Hepatocellular carcinoma Diagnostic Treatment

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Specific detection of the floodwater mosquitoes Aedes sticticus and Aedes vexans DNA in predatory diving beetles

引用

Insect Science 2015年第4期22卷 549-559页

作者： Thomas Z. Persson Vinnersten peter Halvarsson jan O. Lundstrom Department of Ecology and Genetics Evolutionary Biology Centre Uppsala University SE-75236 Uppsala Swedish Biological Mosquito Control Project Nedre Dalalvens Utvecklings AB Gysinge Sweden

Floodwater mosquitoes （Diptera： Culicidae） are associated with periodically flooded wet meadows, marshes, and swamps in floodplains of major rivers worldwide, and their larvae are abundant in the shallow parts of flooded areas. The nuisance caused by the blood-seeking adult female mosquitoes motivates mosquito control. Larviciding with Bacillus thuringiensis israelensis is considered the most environmentally safe method. However, some concern has been raised whether aquatic predatory insects could be indi- rectly affected by this reduction in a potential vital prey. Top predators in the temporary wetlands in the River Dal/ilven floodplains are diving beetles （Coleoptera： Dytiscidae）, and Aedes sticticus andAe, vexans are the target species for mosquito control. For detailed stud- ies on this aquatic predator-prey system, we developed a polymerase chain reaction （PCR） assay for detection of mosquito DNA in the guts of medinm-sized diving beetles. Primers were designed for amplifying short mitochondrial DNA fragments of the cytochrome C oxidase subunit I （COI） gene in Ae. sticticus and Ae. vexans, respectively. Primer speci- ficity was confirmed and half-life detectability ofAe. sticticus DNA in diving beetle guts was derived from a feeding and digestion experiment. The Ae. sticticus DNA within diving beetle guts was detected up to 12 h postfeeding, and half-life detectability was estimated to 5.6 h. In addition, field caught diving beetles were screened for Ae. sticticus and Ae. vexans DNA and in 14% of the diving beetles one or both mosquito species were detected, showing that these mosquito species are utilized as food by the diving beetles.

关键词： Aedes sticticus Dytiscidae floodwater mosquitoes gut content analysis half-life detectability PCR

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Early markers of reperfusion injury after liver transplantation: association with primary dysfunction

引用

Hepatobiliary & Pancreatic Diseases International 2015年第3期14卷 246-252页

作者： Helge Bruns jan Heil Daniel Schultze Mohammed Al Saeedi peter Schemmer Department of General and Transplant Surgery University Hospital Heidelberg

BACKGROUND： In patients with end-stage fiver disease, fiver transplantation is the only available curative treatment. Al- though the outcome and quality of life in the patients have improved over the past decades, primary dys- or nonfimction （PDF/PNF） can occur. Early detection of PDF and PNF is crucial and could lead to individual therapies. This study was designed to identify early markers of reperfusion injury and PDF in liver biopsies taken during the first hour after reperfusion.

关键词： primary dysfunction liver transplantation predictive markers reperfusion injury microarray

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：