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Biomimetic Precipitation of Uniaxially Grown Calcium Phosphate Crystals from Full-Length Human Amelogenin Sols

Journal of Bionic Engineering 2011年第2期8卷 114-121页

作者： Vuk Uskokovie Wu li.stefan Habeli.z Division of Biomaterials and Bioengineering Department of Preventive and Restorative Dental Sciences University of Calil'ornia 707 Parnassus Avenue San Francisco CA 94143 USA Department of Orofacial Sciences University of California 513 Parnassus Avenue San Francisco CA 94143 USA

Human dental enamel forms over a period of 2 4 years by substituting the enamel matrix, a protein gel mostly composed of a single protein, amelogenin with fibrous apatite nanocrystals. Self-assembly of a dense amelogenin matrix is presumed to direct the growth of apatite fibers and their organization into bundles that eventually comprise the mature enamel, the hardest tissue in the mammali.n body. This work aims to establi.h the physicochemical and biochemical conditions for the synthesis of fibrous apatite crystals under the control of a recombinant full-length human amelogenin rnatrix in combination with a pro- grammable titration system. The growth of apatite substrates was initiated from supersaturated calcium phosphate solutions in the presence of dispersed amelogenin assembli.s. It was shown earli.r and confirmed in this study that binding of amelogenin onto apatite surfaces presents the first step that leads to substrate-specific crystal growth. In this work, we report enhanced nucleation and growth under conditions at which amelogenin and apatite carry opposite charges and adsorption of the protein onto the apatite seeds is even more favored. Experiments at pH below the isoelectric point of amelogenin showed increased protein binding to apatite and at low Ca/P molar ratios resulted in a change in crystal morphology from plate-li.e to fibrous and rod-shaped. Concentrations of calcium and phosphate ions in the supernatant did not show drastic decreases throughout the titration period, indicating controlled precipitation from the protein suspension metastable with respect to calcium phosphate. It is argued that amelobtasts in the developing enamel may vary the density of the protein matrix at the nano scale by varying local pH, and thus control the interaction between the mineral and protein phases. The biomimetic experimental setting appli.d in this study has thus proven as convenient for gaining insight into the fundamental nature of the process ofamelogenesi

关键词： enamel amelogenin biominerali.ation apatite biomimetics

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The Asymmetric Connection of SST in the Tasman Sea with Respect to the Opposite Phases of ENSO in Austral Summer

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Advances in Atmospheric Sciences 2022年第11期39卷 1897-1913页

作者： Xueqian SUN Shuangli. li.stefan li.SS Cli.ate Change Research Center(CCRC) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Department of Atmospheric Science/Centre for Severe Weather and Cli.ate and Hydro-geological Hazards China University of GeosciencesWuhan 430074China College of Earth and Planetary Science University of Chinese Academy of SciencesBeijing 100049China Department of Soil Waterand ClimateUniversity of MinnesotaTwin CitiesSt.Paul MN 55108MinnesotaUSA

This study uses li.ear regression and composite analyses to identify a pronounced asymmetric connection of sea surface temperature(SST)in the Tasman Sea with the two opposite phases of El Ni?o-Southern Oscillation(ENSO)during austral *** El Ni?o years,the SST anomali.s(SSTAs)in the Tasman Sea exhibit a dipolar pattern with weak warmth in the northwest and modest cooli.g in the southeast,while during La Ni?a years the SSTAs exhibit a basin-scale warmth with greater *** into the underlying mechanism suggest that this asymmetry arises from a mechanism related to oceanic heat transport,specifically the anomalous Ekman meridional heat transport induced by the zonal wind stress anomali.s,rather than the surface heat fluxes on the air-sea *** analysis reveals that the asymmetry of oceanic heat transport between El Ni?o and La Ni?a years is driven by the asymmetric atmospheric circulation over the Tasman Sea stimulated by the asymmetric diabatic heating in the tropical Pacific between the two opposite ENSO phases.

关键词： El Ni?o-Southern Oscillation SST in the Tasman Sea asymmetric connection surface heat fluxes oceanic heat transport

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A theoretical framework for improved fire suppression by li.king management models with smart early fire detection and suppression technologies

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Journal of Forestry Research 2024年第5期35卷 1-13页

作者： li.Meng Jim O’Hehir Jing Gao stefan Peters Anthony Hay University of South Australi. AdelaideSAAustralia Esk Spatial InvermayTASAustralia

Bushfires are devastating to forest managers,owners,residents,and the natural *** tech-nological advances indicate a potential for faster response times in terms of detecting and suppressing ***,to date,all these technologies have been appli.d in *** paper introduces the latest fire detection and sup-pression technologies from ground to *** operations research method was used to assemble these technologies into a theoretical framework for fire detection and *** framework harnesses the advantages of satelli.e-based,drone,sensor,and human reporting technologies as well as image processing and artificial intelli.ence machine *** study concludes that,if a system is designed to maximise the use of available technologies and carefully adopts them through complementary arrangements,a fire detection and resource suppression system can achieve the ultimate aim:to reduce the risk of fire hazards and the dam-age they may cause.

关键词： Forest fire Resource suppression Smart fire detection and suppression system Forest fire management Holi.tic system

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Theoretical investigation on axial cycli. performance of monopile in sands using interface constitutive models

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2645-2662页

作者： Pan Zhou Jingpei li.Kaoshan Dai stefan Vogt Seyedmohsen Miraei Department of Geotechnical Engineering Tongji UniversityShanghai200092China Department of Civil Geo and Environmental EngineeringTechnical University of MunichFranz-Langinger-Str.10München81245Germany Department of Civil Engineering Sichuan UniversityChengdu610065China

Cycli. loads generated by environmental factors,such as winds,waves,and trains,will li.ely lead to performance degradation in pile foundations,resulting in issues li.e permanent displacement accumulation and bearing capacity *** paper presents a semi-analytical solution for predicting the axial cycli. behavior of piles in *** solution reli.s on two enhanced nonli.ear load-transfer models considering stress-strain hysteresis and cycli. degradation in the pile-soil *** parameters are cali.rated through cycli. shear tests of the sand-steel interface and laboratory geotechnical testing of sands.A novel aspect involves the meticulous formulation of the shaft loadtransfer function using an interface constitutive model,which inherently inherits the interface model’s advantages,such as capturing hysteresis,hardening,degradation,and particle *** semi-analytical solution is computed numerically using the matrix displacement method,and the calculated values are vali.ated through model tests performed on non-displacement and displacement piles in *** results demonstrate that the predicted values show excellent agreement with the measured values for both the static and cycli. responses of piles in *** displacement pile response,including factors such as bearing capacity,mobili.ed shaft resistance,and convergence rate of permanent settlement,exhibit improvements compared to non-displacement piles attributed to the soil squeezing *** methodology presents an innovative analytical framework,allowing for integrating cycli. interface models into the theoretical investigation of pile responses.

关键词： Piles Cycli. degradation Load-transfer models Interface constitutive model Semi-analytical solution Model tests

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Computational Methods for Single-cell Multi-omics Integration and Ali.nment

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Genomics, Proteomics & Bioinformatics 2022年第5期20卷 836-849页

作者： stefan Stanojevic Yijun li.Aleksandar Ristivojevic Lana X.Garmire Department of Computational Medicine and Bioinformatics University of MichiganAnn ArborMI 48109USA Department of Biostatistics University of MichiganAnn ArborMI 48109USA Amherst College AmherstMA 01002USA

Recently developed technologies to generate single-cell genomic data have made a revolutionary impact in the field of ***-omics assays offer even greater opportunities to understand cellular states and biological *** problem of integrating different omics data with very different dimensionali.y and statistical properties remains,however,quite challenging.A growing body of computational tools is being developed for this task,leveraging ideas ranging from machine translation to the theory of networks,and represents another frontier on the interface of biology and data *** goal in this review is to provide a comprehensive,up-to-date survey of computational techniques for the integration of single-cell multi-omics data,while making the concepts behind each algorithm approachable to a non-expert audience.

关键词： Single-cell Multi-omics Machine learning Unsupervised learning Integration

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Channel-resolved subcycle interferences of electron wave packets emitted from H_(2) in two-color laser fields

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High Power Laser Science and Engineering 2016年第4期4卷 1-7页

作者： Xinhua Xie stefan Roither Daniil Kartashov li.Zhang Andrius Baltuska Markus Kitzler Photonics Institute Technische Universitat Wien Institute of Theoretical Chemistry University of Vienna

We report on the observation of subcycle interferences of electron wave packets released during strong field ionization of H_2 with cycle-shaped two-color laser fields. With a reaction microscope we measure three-dimensional momentum distributions of photoelectrons correlated with either H_2^+ or protons within different energy ranges generated by dissociation of H_2^+. We refer to these different types of photoelectrons as channels. Our results show that the subcycle interference structures of electron wave packets are very sensitive to the cycle shape of the two-color laser field. We explain this behavior by the dependence of the ionization time within an optical cycle on the shape of the laser field cycle. The subcycle interference structures can be further used to obtain insight into the subcycle dynamics of molecules during strong field interaction.

关键词： molecular dynamics strong field ionization wave packet interference

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Altitudinal patterns of stand structure and herb layer diversity of Picea schrenkiana forests in the central Tianshan Mountains,Northwest China

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Journal of Arid Land 2011年第4期3卷 254-260页

作者： li.ing li.XiangPing WANG stefan ZERBE li.un ZHANG JingYun FANG Department of Ecology College of Urban and Environmental Sciences ＆ Key Laboratory for Earth Surface Processes of the Ministry of Education Peking University Beijing 100871 China Faculty of Science and Technology Free University of Bolzano Bolzano 39100 Italy The Key Laboratory of Silviculture and Conservation of the Ministry of Education College of Forestry Beijing Forestry University Beijing 100083 China Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China

Altitude is a useful indicator to examine patterns of forest structure and species diversity in relation to environmental *** this study,the altitude patterns of forest stand structure and species diversity were analyzed across 20 plots in the Tianchi Nature Reserve,Northwest *** results showed that mean stem height（Hm）,maximum stem height（Hmax） and mean stem diameter at breast height（Dm） of Picea schrenkiana trees all decreased significantly with increasing *** tree height（H＊） decreased while stem taper increased significantly as altitude increased,suggesting remarkable altitudinal changes in biomass allocation between the diameter and height growth of Picea *** herbaceous richness increased significantly with increasing altitude,or with decreasing total basal area（TBA）,Hm and stand volume（Volume）.High li.ht availabili.y for understory herbs might account for the higher species richness at high *** Index decreased significantly with the increase in altitude intervals,while the Cody Index demonstrated a converse pattern,suggesting greater differences in species composition with larger distances.

关键词： allometry beta diversity species richness Picea schrenkiana Tianshan Mountains Xinjiang

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Convolutional neural network-assisted recognition of nanoscale L1_(2) ordered structures in face-centred cubic alloys

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npj Computational Materials 2021年第1期7卷 60-68页

作者： Yue li.Xuyang Zhou Timoteo Colnaghi Ye Wei Andreas Marek Hongxiang li.stefan Bauer Markus Rampp Leigh T.Stephenson Max-Planck Institut für Eisenforschung GmbH Max-Planck-Straße 140237 DüsseldorfGermany Max Planck Computing and Data Facili.y Gießenbachstraße 285748 GarchingGermany State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing100083 BeijingChina Max Planck Institute for Intelli.ent Systems Max-Planck-Ring 472076 TübingenGermany

Nanoscale L12-type ordered structures are widely used in face-centered cubic(FCC)alloys to exploit their hardening capacity and thereby improve mechanical *** fine-scale particles are typically fully coherent with matrix with the same atomic configuration disregarding chemical species,which makes them challenging to be *** distribution maps(SDMs)are used to probe local order by interrogating the three-dimensional(3D)distribution of atoms within reconstructed atom probe tomography(APT)***,it is almost impossible to manually analyze the complete point cloud(>10 milli.n)in search for the partial crystallographic information retained within the ***,we proposed an intelli.ent L1_(2)-ordered structure recognition method based on convolutional neural networks(CNNs).The SDMs of a simulated L1_(2)-ordered structure and the FCC matrix were firstly *** simulated images combined with a small amount of experimental data were used to train a CNN-based L1_(2)-ordered structure recognition ***,the approach was successfully appli.d to reveal the 3D distribution of L1_(2)–typeδ′–Al3(li.g)nanoparticles with an average radius of 2.54 nm in a FCC Al-li.Mg *** minimum radius of detectable nanodomain is even down to 5Å.The proposed CNN-APT method is promising to be extended to recognize other nanoscale ordered structures and even more-challenging short-range ordered phenomena in the near future.

关键词： alloys ordered cubic

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Circularly polarized phosphorescence and photon transport of micro/nanocrystals of ruthenium and iridium complexes with chiral anions

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Science China Chemistry 2023年第10期66卷 2892-2902页

作者： Zhong-Qiu li.Zhong-li.ng Gong Tongli.g li.ng stefan Bernhard Yu-Wu Zhong Jiannian Yao Beijing National Laboratory for Molecular Sciences(BNLMS) CAS Key Laboratory of PhotochemistryCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Chemistry Carnegie Mellon UniversityPittsburghPennsylvania 15213USA

Materials with efficient circularly polarized phosphorescences(CPPs) are of potential use in advanced data encryption and anticounterfeiting, bioimaging, optoelectronic devices and so forth. Herein, a simple method is presented for the preparations of CPP-active micro/nanocrystals with large luminescence dissymmetry factors(glum), high phosphorescence quantum efficiencies(Φ_(P)) and tunable emission colors. Diastereomeric Ir^(Ⅲ) and Ru^(Ⅱ) complexes with chiral(±)-camphorsulfonate counter-anions are readily synthesized and assembled into crystalli.e microrods, microplates or nanofibers with ordered morphologies. The chirali.y information of chiral counter-anions is efficiently transferred to the metal components to afford CPPs with cyan, green,yellow, or red emission colors and Φ_(P)in the range of 5%–85%. The number of chiral anions is found to play a role in influencing the CPP magnitudes of these crystals. The dicationic Ru^(Ⅱ) and tricationic Ir^(Ⅲ) complexes show glumvalues in the 10^(-2)order, which are much larger with respect to those of monocationic Ir^(Ⅲ) complexes. Single crystal X-ray analysis is performed to obtain information on the chirali.y transfer of these materials. In addition, circularly polarized photonic signal waveguiding is demonstrated using the microcrystals of an Ir^(Ⅲ)complex. This work demonstrates an appeali.g strategy of constructing chiral micro/nano-architectures for potential appli.ations in chiral nanophotonics.

关键词： circularly polarized luminescence transition metal complexes chirali.y transfer micro/nanocrystals photon transport

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Vacuolar Sorting Receptor （VSR） Proteins Reach the Plasma Membrane in Germinating Pollen Tubes

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Molecular Plant 2011年第5期4卷 845-853页

作者： Hao Wang Xiao-Hong Zhuang stefan Hillmer David G. Robinson li.Wen Jiang School of li.e Sciences Centre for Cell and Developmental Biology The Chinese University of Hong Kong Shatin New Territories Hong Kong China State Key Laboratory of Agrobiotechnology The Chinese University of Hong Kong Shatin New Territories Hong Kong China Department of Cell Biology Heidelberg Institute for Plant Science University of Heidelberg Germany

Vacuolar sorting receptors （VSRs） are type I integral membrane proteins that mediate the vacuolar transport of soluble cargo proteins via prevacuolar compartments （PVCs） in plants. Confocal immunofluorescent and immunogold Electron Microscope （EM） studies have locali.ed VSRs to PVCs or multivesicular bodies （MVBs） and trans-Golgi network （TGN） in various plant cell types, including suspension culture cells, root cells, developing and germinating seeds. Here, we provide evidence that VSRs reach plasma membrane （PM） in growing pollen tubes. Both immunofluorescent and immunogold EM studies with specific VSR antibodies show that, in addition to the previously demonstrated PVC/MVB locali.ation, VSRs also locali.e to PM in li.y and tobacco pollen tubes prepared from chemical fixation or high-pressure freezing/frozen substitution. Such a PM locali.ation suggests an additional role of VSR proteins in mediating protein transport to PM and endocytosis in growing pollen tubes. Using a high-speed Spinning Disc Confocal Microscope, the possible fusion between VSR-positive PVC organelles and the PM was also observed in li.ing tobacco pollen tubes transiently expressing the PVC reporter GFP-VSR. In contrast, the lack of a prominent PM locali.ation of GFP-VSR in li.ing pollen tubes may be due to the highly dynamic situation of vesicular transport in this fast-growing cell type.

关键词： Plasma membrane pollen tube vacuolar sorting receptor.

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