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An examination by gC×gC-TOFMS of organic molecules present inhighly degraded oils emerging from Caribbean terrestrial seeps of Cretaceous age

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geoscience Frontiers 2019年第1期10卷 5-15页

作者： Alan g.Scarlett Ana Ibis Despaigne-Diaz simon A.Wilde Kliti grice Western Australian Organic and Isotope geochemistry Centre The Institute for Geoscience Research Curtin University Department of Applied geology The Institute for Geoscience Research Curtin University

For our ancestors, oil seeps were both a fascination and a resource but as the planet's reserves of high quality low density oil becomes increasingly depleted, so there is now a renewed interest in heavier,biodegraded oils such as those encountered in terrestrial seeps. One such seep is Pitch Lake in the Caribbean island of Trinidad, which is the largest natural deposit of asphalt in the world. At the northern end of the Caribbean, oil emerges along a tectonic contact on the island on Cuba. The sources of the oils from these seeps are relatively recent and both are subject to intense weathering due to the tropical conditions. When analysed by gas chromatography(gC) both oils appear as unresolved complex mixtures(UCM) and show a very high degree of biodegradation thus presenting an analytical challenge. In this case study, these two Caribbean seep oils were analysed by comprehensive two dimensional gC with time of flight mass spectrometry(gC×gC-TOFMS) to expose many thousands of the individual compounds that comprise the UCM. The high chromatographic resolution of the gC×gC-TOFMS produced good quality mass spectra allowing many compounds including molecular fossil ‘biomarkers' to be identified. Compound classes included diamondoid hydrocarbons, demethylated hopanes and secohopanes, mono-and tri-aromatic steroids. D-ring aromatised structures of the 8,14-seco-hopanes,including demethylated forms were present in both oils but further demethylation, probably at position C-25 during biodegradation, was only observed in the Pitch Lake oil. Many polycyclic aromatic hydrocarbons(PAHs) were absent although the fungal-derived pentacyclic PAH perylene was present in both oils. The presence of the angiosperm biomarker lupane in the Pitch Lake oil constrained the age to the Late Cretaceous. The higher degree of biodegradation observed in the Cuban oil was likely due to relatively slow anaerobic processes whereas oil within Pitch Lake was probably subject to additional more rapid

关键词： Oil seep Biomarker Biodegradation gCxgC Diamondoids Aromatic steroids

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Semi-global leader-following consensus-based formation flight of unmanned aerial vehicles

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Chinese journal of Aeronautics 2022年第1期35卷 31-43页

作者： Panpan ZHOU ben M.CHEN Department of Mechanical ami Automation Engineering The Chinese University of Hong KongHong KongChina

In this paper,we investigate a formation control problem of multi-agent systems(specifically a group of unmanned aerial vehicles)based on a semi-global leader-following consensus approach with both the leader and the followers subject to input *** the low gain feedback design technique,a distributed static control protocol and a distributed adaptive control protocol are *** former solves the problem under an assumption that the communication network is undirected,and it depends on the global information of the *** the latter,we relax the undirected graph to directed ***,an adaptive updating gain is designed to avoid using the global information of the communication *** is shown that the consensus protocols can solve the semi-global leader-following consensus problem if the leader agent is globally *** results are verified successfully by both simulation and real flight tests.

关键词： Consensus Formation flying Input saturation Low gain feedback Multi-agent systems Unmanned aerial vehicles

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Comparing four machine learning algorithms for household non-intrusive load monitoring

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Energy and AI 2024年第3期17卷 206-219页

作者： Thomas Lee Young james gopsill Maria Valero Sindre Eikevåg ben Hicks University of Bristol UK

The combination of Machine Learning (ML), smart energy meters, and availability of household appliance energy profile data has opened new opportunities for Non-Intrusive Load Monitoring (NILM). However, the number of options makes it challenging in selecting optimal combinations for different energy applications, which requires studies to examine their *** paper contributes one such study that investigated four established ML approaches – K Nearest Neighbour (KNN), Support Vector Machine (SVM), eXtreme gradient Boosting (XgBoost) and Convolutional Neural Network (CNN) – and their performance in classifying appliance events from Alternating Current (AC) and Root Mean Square (RMS) energy data where the sampling frequency and training dataset set size was varied (10 Hz–1 kHz and 50–2000 examples per class, respectively). The computational expense during training, testing and storage was also assessed and evaluated with reference to real-world *** CNN classifier trained on AC data at 500 Hz and 11,000 examples gave the best F1-score (0.989) followed by the KNN classifier (0.940). The storage size required by the CNN models was 3̃MB, which is very close to fitting on cost-effective embedded system microcontrollers. This would prevent high-rate data needing to be sent to the cloud as analysis could be performed on edge computing Internet-of-Things (IoT) devices.

关键词： NILM ML Edge computing Signal processing Smart meters

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Visually constructing the chemical structure of a single molecule by scanning Raman picoscopy

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National Science Review 2019年第6期6卷 1169-1175页

作者： Yao Zhang ben Yang Atif ghafoor Yang Zhang Yu-Fan Zhang Rui-Pu Wang jin-Long Yang Yi Luo Zhen-Chao Dong j.g.Hou Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China

The strong spatial confinement of a nanocavity plasmonic field has made it possible to visualize the inner structure of a single molecule and even to distinguish its vibrational modes in real space. With such ever-improved spatial resolution, it is anticipated that full vibrational imaging of a molecule could be achieved to reveal molecular structural details. Here we demonstrate full Raman images of individual vibrational modes at the ■ level for a single Mg-porphine molecule, revealing distinct characteristics of each vibrational mode in real space. Furthermore, by exploiting the underlying interference effect and Raman fingerprint database, we propose a new methodology for structural determination, which we have called 'scanning Raman picoscopy', to show how such ultrahigh-resolution spectromicroscopic vibrational images can be used to visually assemble the chemical structure of a single molecule through a simple Lego-like building process.

关键词： scanning Raman picoscopy tip-enhanced Raman spectroscopy structure determination vibrational mode imaging interference effect

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Arabinan Metabolism during Seed Development and germination in Arabidopsis

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Molecular Plant 2009年第5期2卷 966-976页

作者： Leonardo D. gomez Clare g. Steele-King Louise jones jonathan M. Foster Supachai Vuttipongchaikij simon j. McQueen-Mason CNAP Department of Biology University of York Heslington York YO10 5YW United Kingdom

Arabinans are found in the pectic network of many cell walls, where, along with galactan, they are present as side chains of Rhamnogalacturonan I. Whilst arabinans have been reported to be abundant polymers in the cell walls of seeds from a range of plant species, their proposed role as a storage reserve has not been thoroughly investigated. In the cell walls of Arabidopsis seeds, arabinose accounts for approximately 40% of the monosaccharide composition of non- cellulosic polysaccharides of embryos. Arabinose levels decline to -15% during seedling establishment, indicating that cell wall arabinans may be mobilized during germination. Immunolocalization of arabinan in embryos, seeds, and seedlings reveals that arabinans accumulate in developing and mature embryos, but disappear during germination and seedling establishment. Experiments using 14C-arabinose show that it is readily incorporated and metabolized in growing seedlings, indicating an active catabolic pathway for this sugar. We found that depleting arabinans in seeds using a fungal arabinanase causes delayed seedling growth, lending support to the hypothesis that these polymers may help fuel early seedling growth.

关键词： Cell walls development embryogenesis and seed development Arabidopsis arabinan arabinose carbohydrate metabolism physiology of plant growth.

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Evaluation of Protein Extraction Methods for Vitis vinifera Leaf and Root Proteome Analysis by Two-Dimensional Electrophoresis

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journal of Integrative Plant Biology 2010年第10期52卷 933-940页

作者： Neila jellouli Asma ben Salem Abdelwahed ghorbel Hatem ben jouira Laboratoire de Physiologie Moléculaire de la Vigne Centre de Biotechnologie de Borj Cédria

An efficient protein extraction method is crucial to ensure successful separation by two-dimensional electrophoresis （2-DE） for recalcitrant plant species, in particular for grapevine （Vitis vinifera L.）. Trichloroacetic acid-acetone （TCA-acetone） and phenol extraction methods were evaluated for proteome analysis of leaves and roots from the Tunisian cultivar ＇Razegui＇. The phenol-based protocol proved to give a higher protein yield, a greater spot resolution, and a minimal streaking on 2-DE gels for both leaf and root tissues compared with the TCA-based protocol. Furthermore, the highest numbers of detected proteins on 2-DE gels were observed using the phenol extraction from leaves and roots as compared with TCA-acetone extraction.

关键词： Proteins Protein products Extraction Extracts Acetone Tca Separating Methods Colloids Roots

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Imaging of liver cancer

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World journal of gastroenterology 2009年第11期15卷 1289-1300页

作者： ben Ariff Claire R Lloyd Sameer Khan Mohamed Shariff Andrew V Thillainayagam Devinder S Bansi Shahid A Khan simon D Taylor-Robinson Adrian KP Lim Department of Imaging Imperial College Healthcare NHS Trust Charing Cross Hospital Campus Fulham Palace Road London W6 8RF United Kingdom Department of Hepatology and gastroenterology Division of Medicine Imperial College London St Mary's Hospital Campus South Wharf Road London W2 1NY United Kingdom

Improvements in imaging technology allow exploitation of the dual blood supply of the liver to aid in the identif ication and characterisation of both malignant and benign liver lesions. Imaging techniques available include contrast enhanced ultrasound, computed tomography and magnetic resonance imaging. This review discusses the application of several imaging techniques in the diagnosis and staging of both hepatocellular carcinoma and cholangiocarcinoma and outlines certain characteristics of benign liver lesions. The advantages of each imaging technique are highlighted, while underscoring the potential pitfalls and limitations of each imaging modality.

关键词： Hepatic cell carcinoma Cholangiocarcinoma Contrast enhanced ultrasound Computed tomography Magnetic resonance imaging

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Heterogeneous 2D/3D photonic integrated microsystems

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Microsystems & Nanoengineering 2016年第1期2卷 143-151页

作者： S.j.ben Yoo Binbin guan Ryan P.Scott Department of Electrical and Computer Engineering University of CaliforniaDavisCA 95616USA

The continuing trend of exponential growth in data communications and processing are driving the need for large-scale heterogeneous *** to the trend we have observed in electronic integrated circuit development,we are witnessing a growing trend in 3D photonic integrated circuits(PICs)development in addition to that in 2D *** are two main methods for fabricating 3D *** first method,which utilizes ultrafast laser inscription(ULI),offers freeform shaping of waveguides in arbitrary contours and *** second method,which utilizes multilayer stacking and coupling of planar PICs,exploits relatively mature 2D PIC fabrication processes applied to each layer *** the fabrication methods for 3D PICs have advantages and disadvantages such that certain applications may favor one method over the ***,a joining of 2D PICs with 3D PICs can help develop integrated microsystems with new functionalities such as non-mechanical beam steering,spacedivision multiplexing(SDM),programmable arbitrary beam shaping,and photonic signal *** discuss examples of 3D PICs and 2D/3D integrated PICs in two applications:SDM via orbital-angular-momentum(OAM)multiplexing/demultiplexing and optical beam steering using optical phased *** a 2D PIC by itself can function as an OAM multiplexer or demultiplexer,it has limitations in supporting both ***,a 3D PIC fabricated by ULI can easily support both polarizations with low propagation loss.A combination of a 3D PIC and a 2D PIC designed and fabricated for OAM applications has successfully multiplexed and demultiplexed 15 OAM states to demonstrate polarization-diversified SDM coherent optical communications using multiple OAM *** excitation of multi-ring OAM states can allow highly scalable SDM utilizing Laguerre–gaussian modes or linearly polarized(LP)*** preliminary fabrication of multi-ring OAM multiplexers and demultiplexers using the

关键词： photonic integrated circuits three-dimensional photonics ultrafast laser inscription

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Characterization of colonic dendritic cells in normal and colitic mice

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World journal of gastroenterology 2005年第40期11卷 6338-6347页

作者： Sheena M Cruickshank Nicholas R English Peter j Felsburg simon R Carding Institute of Molecular and Cellular Biology Antigen Presentation Research group Department of Clinical Science

AIM： Recent studies demonstrating the direct involvement of dendritic cells （DC） in the activation of pathogenic T cells in animal models of inflammatory bowel disease identify DC as important antigen presenting cells in the colon. However, very little is known about the properties of colonic DC. METHODS： Using immunohistochemistry, electron microscopy and flow cytometry we have characterized and compared colonic DC in the colon of healthy animals and interleukin-2-deficient （IL2-/-） mice that develop colitis. RESULTS： In the healthy colon, DC resided within the lamina propria and in close association with the basement membrane of colonic villi. Type i myeloid （CD11c^＋, CD11b^＋, B220, CD8） DC made up the largest （40-45%） population and all DC expressed low levels of CD80, CD86, and CD40, and had high endooltic activity consistent with an immature phenotype. In colitic IL2-/- mice, colonic DC numbers increased four- to five-fold and were localized within the epithelial layer and within aggregates of T and B cells. They were also many more DC in mesenteric lymph nodes （MLN）. The majority （〉85%） of DC in the colon and MLN of IL2./ mice were type 1 myeloid, and expressed high levels of MHC class II, CD80, CD86, CD40, DEC 205, and CCR5 molecules and were of low endocytic activity consistent with mature DC. CONCLUSION： These findings demonstrate striking changes in the number, distribution and phenotype of DC in the inflamed colon. Their intimate association with lymphocytes in the colon and draining lymph nodes suggest that they may contribute directly to the ongoing inflammation in the colon.

关键词： Colonic dendritic cells Interleukin 2 Colitis

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基于环形结构的无源编码超表面设计

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新疆师范大学学报（自然科学版） 2025年第2期44卷 27-35页

作者：陈燕王静王本贤新疆师范大学物理与电子工程学院新疆发光矿物与光功能材料研究重点实验室新疆乌鲁木齐830054

编码超表面可通过编码序列调控空间波束方向,有利于无线通信系统目标用户定向传输和通信质量的提高。文章设计了工作在3.5 gHz的环形周期金属贴片的三层结构单元超表面,通过改变单元结构尺寸,得到基本编码单元,将编码单元按照不同方式排... 详细信息

编码超表面可通过编码序列调控空间波束方向,有利于无线通信系统目标用户定向传输和通信质量的提高。文章设计了工作在3.5 gHz的环形周期金属贴片的三层结构单元超表面,通过改变单元结构尺寸,得到基本编码单元,将编码单元按照不同方式排布,在此条件下实现单波束、双波束电磁波辐射。采用卷积运算的波束调控方法,垂直入射平面波激励下,反射波束角度的最大值由传统排布方式下的30°扩大至51°,而最小反射波束角度达到5°,为超表面上电磁波束的连续灵活调控提供了一种新思路。

关键词：编码超表面波束调控卷积运算

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