检索结果-南通市图书馆

Wafer Scale Synthesis of Dense Aligned Arrays of Single-Walled Carbon Nanotubes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2008年第2期1卷 158-165页

作者： Weiwei Zhou christopher Rutherglen Peter j.Burke Department of Electrical Engineering and Computer Science University of CaliforniaIrvineCA 92697USA

Here we present an easy one-step approach to pattern uniform catalyst lines for the growth of dense,aligned parallel arrays of single-walled carbon nanotubes(SWNTs)on quartz wafers by using photolithography or polydimethylsiloxane(PDMS)stamp microcontact printing(μCP).By directly doping an FeCl3/methanol solution into Shipley 1827 photoresist or polyvinylpyrrolidone(PVP),various catalyst lines can be well-patterned on a wafer *** addition,during the chemical vapor deposition(CVD)growth of SWNTs the polymer layers play a very important role in the formation of mono-dispersed *** universal and effi cient method for the patterning growth of SWNTs arrays on a surface is compatible with the micro-electronics industry,thus enabling of the fabrication highly integrated circuits of SWNTs.

关键词： Single-walled carbon nanotubes(SWNTs) chemical vapor deposition(CVD) photolithography microcontact printing(μCP)

Characterizing functional consequences of DNA copy number alterations in breast and ovarian tumors by spaceMap

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

journal of Genetics and Genomics 2018年第7期45卷 361-371页

作者： christopher j.Conley Umut Ozbek Pei Wang jie Peng Department of Statistics University of California Davis Department of Population Health Science and Policy Icahn School of Medicine at Mount Sinai Department of Genetics and Genomic Sciences Icahn School of Medicine at Mount Sinai

We propose a novel conditional graphical model -- spaceMap -- to construct gene regulatory networks from multiple types of high dimensional omic profiles. A motivating application is to characterize the perturbation of DNA copy number alterations （CNAs） on downstream protein levels in tumors. Through a penalized multivariate regression framework, spaceMap jointly models high dimensional protein levels as responses and high dimensional CNAs as predictors. In this setup, spaceMap infers an undirected network among proteins together with a directed network encoding how CNAs perturb the protein network, spaceMap can be applied to learn other types of regulatory relationships from high dimensional molecular profiles, especially those exhibiting hub structures. Simulation studies show spaceMap has greater power in detecting regulatory relationships over competing methods. Additionally, spaceMap includes a network analysis toolkit for biological interpretation of inferred networks. We applies spaceMap to the CNAs, gene expression and proteomics data sets from CPTAC-TCGA breast （n = 77） and ovarian （n = 174） cancer studies. Each cancer exhibits disruption of＇ion transmembrane transport＇ and ＇regulation from RNA polymerase lI promoter＇ by CNA events unique to each cancer. Moreover, using protein levels as a response yields a more functionally-enriched network than using RNA expressions in both cancer types. The network results also help to pinpoint crucial cancer genes and provide insights on the functional consequences of important CNA in breast and ovarian cancers.

关键词： Integrative genomics Proteogenomics Conditional graphical models Network analysis

Heterozygous carriers of galactocerebrosidase mutations that cause Krabbe disease have impaired microglial function and defective repair of myelin damage

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2018年第3期13卷 393-401页

作者： Nicole j.Scott-Hewitt christopher j.Folts Mark D.Noble Department of Biomedical Genetics University of Rochester School of Medicine and Dentistry

This review addresses two puzzling findings related to mutations in galactocerebrosidase （GALC） that cause Krabbe disease （KD）, a severe lysosomal storage disorder characterized by extensive myelin damage in children with mutations in both GALC alleles. First, heterozygous carriers of KD-causing mutations, which include the biological parents of children with KD, exhibit increased risk for developing other diseases. Second, variants in the GALC locus increase the risk of developing multiple sclerosis （MS）, another disease characterized by extensive myelin damage. What explains these correlations？ In studies on cuprizone-induced myelin damage in heterozygous （GALC＋/–） mice carrying one copy of a mutation that causes KD-like disease, the extent of damage was similar in GALC＋/– and wild-type （WT） mice. In contrast, GALC＋/- mice had striking defects in repair of cuprizone-induced damage. We further found unexpected microglial defects in myelin debris clearance and in the ability to up-regulate the Trem2 microglial protein critical for debris uptake. These defects were rescued by exposure to a lysosomal re-acidifying drug discovered in our studies on KD, and which provides multiple clinically relevant benefits in the twitcher （GALC＋/–） mouse model of KD. Thus, heterozygous GALC mutations cause effects on biological function that may help to understand the increased disease risk in heterozygous carriers of such mutations and to understand why GALC variations increase the risk of MS. Our findings indicate that while some genetic risk factors may contribute to complex diseases by increasing the risk of tissue damage, others may do so by compromising tissue repair.

关键词： vulnerability locus multiple sclerosis Krabbe disease galactocerebrosidase microglia myelin repair lysosomal storage disorders heterozygous carriers Trem2 demyelination

Bank erosion in an Andean páramo river system: Implications for hydro-development and carbon dynamics in the neotropical Andes

在线全文

学校读者我要写书评

暂无评论

journal of Mountain Science 2019年第2期16卷 243-255页

作者： Derek j.MARTIN christopher ELY Beverley C.WEMPLE Department of Geography and Planning Appalachian State University Department of Geography University of Vermont

The páramo of the Northern Andes provide critically important ecosystem services to the Northern Andean region in the form of water provisioning and carbon sequestration, both of which are a result of the páramo?s organic-rich soils. Little is known, however, about the hydro-geomorphic characteristics of the rivers that drain these ecosystems. With impending plans for widespread hydro-development and increasing implementation of carbon-sequestering compensation for ecosystem services programs in the region it is imperative that we develop a thorough understanding of the hydrogeomorphic role that rivers play in this unique ecosystem. The objective of this study was to quantify bank erosion along an Amazonian headwater stream draining a small, relatively undisturbed páramo catchment to gain a better understanding of the natural erosion regime and the resulting sediment contributions from this unique ecosystem. This study implemented a combination of field, laboratory, and Geographic Information Systems techniques to quantify bank erosion rates and determine a bank erosion sediment yield from the Ningar River, a small páramo catchment(22.7 km^2) located in the eastern Andean cordillera of Ecuador. Results show that bank erosion rates range from 3.0 to ≥ 390.0 mm/yr, are highly episodic, and yield at least 487 tons of sediment annually to the Ningar River. These results imply that 1) páramo ecosystems substantially contribute to the sediment load of the Amazon River basin; 2) bank erosion is a potentially significant flux component of basin-scale carbon cycles in páramo ecosystems; and 3) hydrologic alteration campaigns(dam building) will likely critically alter these contributions and concomitantly disconnect a critical source of sediment and nutrients to downstream ecosystems.

关键词： Bank erosion Páramo Fluvial geomorphology Andes

Using Bayesian multitemporal classification to monitor tropical forest cover changes in Kalimantan,Indonesia

在线全文

学校读者我要写书评

暂无评论

International journal of Digital Earth 2022年第1期15卷 2061-2077页

作者： Inggit Lolita Sari christopher j.Weston Glenn j.Newnham Liubov Volkova Faculty of Science School of Ecosystem and Forest SciencesThe University of MelbourneCreswickAustralia Research Center for Remote Sensing National Research and Innovation Agency (BRIN)JakartaIndonesia CSIRO Land and Water Clayton SouthAustralia

Significant areas of native forest in Kalimantan,on the island of Borneo,have been cleared for the expansion of plantations of oil palm and *** this study multisource remote sensing was used to develop a time series of land cover maps that distinguish native forest from *** a study area in east Kalimantan,Landsat images were combined with either ALOS PALSAR or Sentinel-1 images to map four land cover classes(native forest,oil palm plantation,rubber plantation,non-forest).Bayesian multitemporal classification was applied to increase map accuracy and maps were validated using a confusion matrix;final map overall accuracy was>90%.Over 18 years from 2000 to 2018 nearly half the native forests in the study area were converted to either non-forest or plantations of either rubber or oil palm,with the highest losses between 2015 and *** upwards from 2008 large areas of degraded or cleared forests,mapped as non-forest,were converted to oil palm *** of native forests to plantation mainly occurred in lowland and wetland forest,while significant forest regrowth was detected in degraded *** maps will help Indonesia with strategies and policies for balancing economic growth and conservation.

关键词： Multitemporal classification Bayesian networks Landsat ALOS PALSAR sentinel-1 Indonesia

Adaptively driven X-ray diffraction guided by machine learning for autonomous phase identification

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2023年第1期9卷 2036-2043页

作者： Nathan j.Szymanski christopher j.Bartel Yan Zeng Mouhamad Diallo Haegyeom Kim Gerbrand Ceder Department of Materials Science&Engineering UC BerkeleyBerkeleyCA 94720USA Materials Sciences Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA

Machine learning(ML)has become a valuable tool to assist and improve materials characterization,enabling automated interpretation of experimental results with techniques such as X-ray diffraction(XRD)and electron *** ML models are fast once trained,there is a key opportunity to bring interpretation in-line with experiments and make on-the-fly decisions to achieve optimal measurement effectiveness,which creates broad opportunities for rapid learning and information extraction from ***,we demonstrate such a capability with the development of autonomous and adaptive *** coupling an ML algorithm with a physical diffractometer,this method integrates diffraction and analysis such that early experimental information is leveraged to steer measurements toward features that improve the confidence of a model trained to identify crystalline *** validate the effectiveness of an adaptive approach by showing that ML-driven XRD can accurately detect trace amounts of materials in multi-phase mixtures with short measurement *** improved speed of phase detection also enables in situ identification of short-lived intermediate phases formed during solid-state reactions using a standard in-house *** findings showcase the advantages of in-line ML for materials characterization and point to the possibility of more general approaches for adaptive experimentation.

关键词： phase diffraction autonomous

Timescales of geological processes: Preface

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geoscience Frontiers 2019年第1期10卷 1-3页

作者： Andrew Putnis christopher j.Spencer Tom Raimondo The Institute for Geoscience Research School of Earth and Planetary Science Curtin University School of Natural and Built Environments University of South Australia

*** One of the major challenges in Geoscience is to understand how the formation and evolution of the Earth System are governed by timescales-that is,how the various geological processes that continue to contribute to its present-day structure and composition operated in the deep *** traditional view of such processes refers to events that occur at immense spatial scales and over hundreds of millions of years,constrained in most cases by the ages of rocks determined using isotopic dating methods or the fossil ***,the modern view of geological processes has increasingly acknowledged that their durations can be significantly shorter than previously thought possible,or indeed detectable without recent analytical *** are a prime example of rapid,high energy and episodic events that have a profound effect on subsequent processes such as metamorphism,fluid transport,and ore formation e the evidence of which is written in microstructures,compositional zoning,and P-T *** studies have also revealed that the reaction rates between fluids and rocks can be extremely rapid relative to geological *** has led to the notion that geological processes are not necessarily continuous over millions of years but may,in fact,be sporadic,with long periods where essentially no reactions take place punctuated by periods of intense activity.

关键词： In Preface Timescales of geological processes

Secular change in earth processes： Preface

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2018年第4期9卷 965-966页

作者： Richard M.Palin christopher j.Spencer Department of Geology and Geological Engineering Colorado School of Mines Golden CO 80401 USA The Institute of Geoscience Research (TIGER) School of Earth and Planetary Sciences Curtin University WA 6102 Australia

*** Uniformitarianism is a traditional approach used in many areas of geoscience that assumes the geologic processes observed today operated similarly throughout all of Earth history（Hutton,1788;Windley,1993）,with such an ideology commonly encapsulated by the maxim＂the present is the key to the past＂.This concept is closely associated with the philosophical principle of Occam’s razor.

关键词： Secular change in earth processes Preface

On Systems of Boundary Value Problems for Differential Inclusions

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2007年第3期23卷 549-556页

作者： Lynn ERBE christopher C.TISDELL Patricia j.Y.WONG Department of Mathematics The University of Nebraska-LincolnLincolnNE 68588-0130USA School of Mathematics and Statistics The University of New South WalesSydney 2052Australia School of Electrical and Electronic Engineering Nanyang Technological University50 Nanyan9 AvenueSingapore 639798Singapore

Herein we consider the existence of solutions to second-order, two-point boundary value problems （BVPs） for systems of ordinary differential inclusions. Some new Bernstein-Nagumo conditions are presented that ensure a priori bounds on the derivative of solutions to the differential inclusion. These a priori bound results are then applied, in conjunction with appropriate topological methods, to prove some new existence theorems for solutions to systems of BVPs for differential inclusions. The new conditions allow of the treatment of systems of BVPs without growth restrictions.

关键词： boundary value problem, systems of differential inclusions, existence of solutions a priori bounds Bernstein-Nagumo condition