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Promoting axon regeneration in the central nervous system by increasing PI3-kinase signaling

Neural Regeneration Research 2022年第6期17卷 1172-1182页

作者： Bart Nieuwenhuis richard Eva John van Geest Center for Brain Repair Department of Clinical NeurosciencesUniversity of CambridgeCambridgeUK

Much research has focused on the PI3-kinase and PTEN signaling pathway with the aim to stimulate repair of the injured central nervous *** in the central nervous system fail to regenerate,meaning that injuries or diseases that cause loss of axonal connectivity have life-changing *** 2008,genetic deletion of PTEN was identified as a means of stimulating robust regeneration in the optic *** is a phosphatase that opposes the actions of PI3-kinase,a family of enzymes that function to generate the membrane phospholipid PIP_(3) from PIP_(2)(phosphatidylinositol(3,4,5)-trisphosphate from phosphatidylinositol(4,5)-bisphosphate).Deletion of PTEN therefore allows elevated signaling downstream of PI3-kinase,and was initially demonstrated to promote axon regeneration by signaling through *** recently,additional mechanisms have been identified that contribute to the neuron-intrinsic control of regenerative *** review describes neuronal signaling pathways downstream of PI3-kinase and PIP3,and considers them in relation to both developmental and regenerative axon *** briefly discuss the key neuron-intrinsic mechanisms that govern regenerative ability,and describe how these are affected by signaling through *** highlight the recent finding of a developmental decline in the generation of PIP_(3) as a key reason for regenerative failure,and summarize the studies that target an increase in signaling downstream of PI3-kinase to facilitate regeneration in the adult central nervous ***,we discuss obstacles that remain to be overcome in order to generate a robust strategy for repairing the injured central nervous system through manipulation of PI3-kinase signaling.

关键词： axon cytoskeleton axon regeneration axon transport cell signaling central nervous system growth cone neuroprotection PI3-kinase PI3K PTEN trafficking transcription translation

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Distribution of Panama’s narrow-range trees:are there hot-spots?

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Forest Ecosystems 2021年第4期8卷 801-809页

作者： Elizabeth Tokarz richard Condit Morton Arboretum 4100 Illinois Rte.53LisleIL 60532USA

Background:Tree species with narrow ranges are a conservation concern because heightened extinction risk accompanies their small *** risks for these species is challenging,however,especially in tropical flora where their sparse populations seldom appear in traditional plots and ***,we utilize instead large scale databases that combine tree records from many sources to test whether the narrow-range tree species of Panama are concentrated at certain elevations or in certain *** investigations have suggested that the Choco region of eastern Panama and the high mountains of western Panama may be potential hotspots of narrow-range tree ***:All individual records were collected from public databases,and the range size of each tree species found in Panama was estimated as a polygon enclosing all its *** with ranges<20,000 km^(2) were defined as narrow *** divided Panama into geographic regions and elevation zones and counted the number of individual records and the species richness in each,separating narrow-range species from all other ***:The proportion of narrow endemics peaked at elevations above 2000 m,reaching 17.2% of the species *** elevation<1500 m across the country,the proportion was 6-11%,except in the dry Pacific region,where it was 1.5%.Wet forests of the Caribbean coast had 8.4% narrow-range species,slightly higher than other *** total number of narrow endemics,however,peaked at mid-elevation,not high elevation,because total species richness was highest at ***:High elevation forests of west Panama had higher proportions of narrow endemic trees than low-elevation regions,supporting their hot-spot status,while dry lowland forests had the lowest *** supports the notion that montane forests of Central America should be a conservation ***,given generally higher diversity at low-to mid-elevation,lowlands are also import

关键词： Narrow endemic trees Biodiversity hot-spots Panama Rarefaction High elevations BIEN database Narrow-range

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Database Commons:A Catalog of Worldwide Biological Databases

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Genomics, Proteomics & Bioinformatics 2023年第5期21卷 1054-1058页

作者： Lina Ma Dong Zou Lin Liu Huma Shireen Amir AAbbasi Alex bateman Jingfa Xiao Wenming Zhao Yiming Bao Zhang Zhang National Genomics Data Center Beijing Institute of GenomicsChinese Academy of Sciences and China National Center for BioinformationBeijing 100101China CAS Key Laboratory of Genome Sciences and Information Beijing Institute of GenomicsChinese Academy of Sciences and China National Center for BioinformationBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China National Center for Bioinformatics Programme of Comparative and Evolutionary GenomicsFaculty of Biological SciencesQuaid-i-Azam UniversityIslamabad 45320Pakistan European Molecular Biology Laboratory European Bioinformatics Institute(EMBL-EBI)HinxtonCambridge CB101SDUnited Kingdom

Biological databases serve as a global fundamental infrastructure for the worldwide scientific community,which dramatically aid the transformation of big data into knowledge discovery and drive significant innovations in a wide range of research *** the rapid data production,biological databases continue to increase in size and *** build a catalog of worldwide biological databases,we curate a total of 5825 biological databases from 8931 publications,which are geographically distributed in 72 countries/regions and developed by 1975 institutions(as of September 20,2022).We further devise a z-index,a novel index to characterize the scientific impact of a database,and rank all these biological databases as well as their hosting institutions and countries in terms of citation and ***,we present a series of statistics and trends of worldwide biological databases,yielding a global perspective to better understand their status and impact for life and health *** up-to-date catalog of worldwide biological databases,as well as their curated meta-information and derived statistics,is publicly available at Database Commons(https://***/databasecommons/).

关键词： Biological database Catalog Database Commons Citation z-index

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Safeguarding our future by protecting biodiversity

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Plant Diversity 2020年第4期42卷 221-228页

作者： richard T.Corlett Center for Integrative Conservation Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaYunnan666303China Center of Conservation Biology Core Botanical GardensChinese Academy of SciencesMenglaYunnan666303China

The Anthropocene is marked by twin crises:climate change and biodiversity *** change has tended to dominate the headlines,reflecting,in part,the greater complexity of the biodiversity *** itself is a difficult *** plants dominate the global biomass and terrestrial arthropods probably dominate in terms of numbers of species,but most of the Tree of Life consists of single-celled eukaryotes,bacteria,and *** plants provide a huge variety of products and services to people,ranging from those that are species-specific,such as food,medicine,and genetic resources,to many which are partly interchangeable,such as timber and forage for domestic animals,and others which depend on the whole community,but not on individual species,such as regulation of water supply and carbon *** use of information from remote sensing has encouraged a simplified view of the values of nature's contributions to people,but this does not match the way most people value *** can currently estimate the proportion of species threatened by human impacts only for a few well-assessed groups,for which it ranges from 14%(birds)to 63%(cycads).Less than 8%of land plants have been assessed,but it has been estimated that 30e44%are threatened,although there are still few(0.2%)well-documented *** for improving protection of biodiversity include:improving the inventory,with surveys focused on geographical areas and taxonomic groups which are under-collected;expanding the protected area system and its representativeness;controlling overexploitation;managing invasive species;conserving threatened species ex situ;restoring degraded ecosystems;and controlling climate *** Convention on Biological Diversity(CBD)COP15 and the United Nations Framework Convention on Climate Change(UNFCCC)COP26 meetings,both postponed to 2021,will provide an opportunity to address both crises,but success will require high ambition from all participants.

关键词： Anthropocene Climate change Conservation Ecosystem services Values

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Rough Sets,Their Extensions and Applications

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International Journal of Automation and computing 2007年第3期4卷 217-228页

作者： richard Jensen Department of Computer Science The University of Wales AberystwythCeredigion SY23 3DBUK

Rough set theory provides a useful mathematical foundation for developing automated computational systems that can help understand and make use of imperfect knowledge. Despite its recency, the theory and its extensions have been widely applied to many problems, including decision analysis, data mining, intelligent control and pattern recognition. This paper presents an outline of the basic concepts of rough sets and their major extensions, covering variable precision, tolerance and fuzzy rough sets. It also shows the diversity of successful applications these theories have entailed, ranging from financial and business, through biological and medicine, to physical, art, and meteorological.

关键词： Rough sets data processing fuzzy sets

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Test-Particle Simulation of Space Plasmas

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Communications in Computational Physics 2010年第8期8卷 471-483页

作者： richard Marchand Department of Physics University of Alberta1132289 AvenueEdmontonAlbertaT6G 2G7Canada

Test-particle simulations provide a useful complement to the kinetic simulations of many-body systems and their approximate treatment with multiple *** a kinetic approach,systems are described at a microscopic level in terms of a large number of degrees of *** or multiple moment approaches,however,provide a description at the macroscopic level,in terms of relatively few physical parameters involving averages or moments of particle distribution ***,fully kinetic descriptions should be done whenever *** to their complexity,the use of these approaches is often not practical in many cases of *** comparison,the fluid approximation is much simpler to implement and *** can be used to describe complex phenomena in multi-dimensional geometry with realistic boundary *** main drawback is its inability to account for many phenomena taking place on fine space or time scales,or phenomena involving nonlocal *** approaches are also not adapted to describe large deviations from local equilibrium,such as the occurrence of particle beams or otherwise strong *** the test-particle method,particle trajectories are calculated using approximated fields obtained from a low level approach,such as multiple *** fields can also be obtained from experiments or *** that these fields are representative of actual systems,various kinetic and statistical properties of the system can then be calculated,such as particle distribution functions and moments *** this paper,the test-particle method is discussed in the context of classical statistical physics of many-body interacting point *** different formulations of the method are presented,which correspond to four broad categories of the application encountered in the field of plasma physics and astronomy.

关键词： Test-particle method first order kinetic modelling space plasmas

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RecBERT:Semantic recommendation engine with large language model enhanced query segmentation for k-nearest neighbors ranking retrieval

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Intelligent and Converged Networks 2024年第1期5卷 42-52页

作者： richard Wu the Dublin Unified School District and the SF Artificial Intelligence Club DublinCA 94568USA

The increasing amount of user traffic on Internet discussion forums has led to a huge amount of unstructured natural language data in the form of user *** modern recommendation systems rely on manual tagging,relying on administrators to label the features of a class,or story,which a user comment corresponds *** common approach is to use pre-trained word embeddings to compare class descriptions for textual similarity,then use a distance metric such as cosine similarity or Euclidean distance to find top k ***,neither approach is able to fully utilize this user-generated unstructured natural language data,reducing the scope of these recommendation *** paper studies the application of domain adaptation on a transformer for the set of user comments to be indexed,and the use of simple contrastive learning for the sentence transformer fine-tuning process to generate meaningful semantic embeddings for the various user comments that apply to each *** order to match a query containing content from multiple user comments belonging to the same class,the construction of a subquery channel for computing class-level similarity is *** channel uses query segmentation of the aggregate query into subqueries,performing k-nearest neighbors(KNN)search on each individual *** achieves state-of-the-art performance,outperforming other state-of-the-art models in accuracy,precision,recall,and F1 score for classifying comments between four and eight classes,*** outperforms the most precise state-of-the-art model(distilRoBERTa)in precision by 6.97%for matching comments between eight classes.

关键词： sentence transformer simple contrastive learning large language models query segmentation k-nearest neighbors

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Production Process and Properties of a Highly Porous Al Alloy Made Using NaCl Droplets as a Space Holder

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Acta Metallurgica Sinica(English Letters) 2015年第8期28卷 1034-1040页

作者： Manuela Covaciu Andrew richard Kennedy Faculty of Engineering University of Nottingham Faculty of Material Science and Engineering Universitatea Tehnica din Cluj-Napoca School of Engineering Pontificia Universidad Católica de Chile

Porous Al structures have been made using a porogen leaching method but with additional novel steps. In this way, Al-0.25Cu-0.6Si-1.0Mg alloys with interconnected, open cells have been made, with high levels of porosity（up to 89%）. The use of 4 to 5 mm diameter sodium chloride droplets combined with interspersion of the metal powder and droplets in the die and dissolution of the salt before sintering was found to enable easier interspersion of the two components, resulting in good connectivity of the beads via the formation of ‘‘windows＇＇ between the pores, and rapid elimination of salt from the structure. Porous Al with densities in the range of 0.28–0.86 g/cm3 exhibited compressive yield strengths in the range of 0.14 to 7.5 MPa, with no difference being observed between the samples made by this route and by more conventional dissolution of the salt after sintering. These novel steps widen the possibility for porous metal manufacture to other materials, not limited by the need to have a sintering temperature below that for the melting point of salt.

关键词： Aluminium alloy Sodium chloride Porous metal

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A framework for quantifying properties of 3-dimensional movement-based signals

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Current Zoology 2010年第3期56卷 327-336页

作者： Shaun TD NEW richard A PETERS ARC Centre of Excellence in Vision Science Division of EvolutionEcology & GeneticsResearch School of BiologyThe Australian National University

Understanding how signal properties are optimized for the reliable transmission of information requires accurate de- scription of the signal in time and space. For movement-based signals where movement is restricted to a single plane, measure- ments from a single viewpoint can be used to consider a range of viewing positions based on simple geometric calculations. However, considerations of signal properties from a range of viewing positions for movements extending into three-dimensions （3D） are more problematic. We present here a new framework that overcomes this limitation, and enables us to quantify the extent to which movement-based signals are view-specific. To illustrate its application, a Jacky lizard tail flick signal was filmed with synchronized cameras and the position of the tail tip digitized for both recordings. Camera aligmnent enabled tl^e construction of a 3D display action pattern profile. We analyzed the profile directly and used it to create a detailed 3D animation. In the virtual environment, we were able to film the same signal from multiple viewing positions and using a computational motion analysis algorithm （gradient detector model） to measure local image velocity in order to predict view dependent differences in signal properties. This approach will enable consideration of a range of questions concerning movement-based signal design and evolu- tion that were previously out of reach [Current Zoology 56 （3）： 327-336, 2010].

关键词： Signal evolution Sensory Ecology Movement-based signal 3D Display Action Pattern

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Performance of slotted pores in particle manufacture using rotating membrane emulsification

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Particuology 2009年第2期7卷 114-120页

作者： Nita Aryanti richard A. Williams Institute of Particle Science and Engineering School of ProcessEnvironmental & Materials EngineeringUniversity of LeedsLeeds LS2 9JTUK

This paper addresses the use of different slotted pores in rotating membrane emulsification technology. Pores of square and rectangular shapes were studied to understand the effect of aspect ratio （1-3.5） and their orientation on oil droplet formation. Increasing the membrane rotation speed decreased the droplet size, and the oil droplets produced were more uniform using slotted pores as compared to circular geometry. At a given rotation speed, the droplet size was mainly determined by the pore size and the fluid velocity of oil through the pore （pore fluid velocity）. The ratio of droplet diameter to the equivalent diameter of the slotted pore increased with the pore fluid velocity. At a given pore fluid velocity and rotation speed, pore orientation significantly influences the droplet formation rate： horizontally disposed pores （with their longer side perpendicular to the membrane axis） generate droplets at double the rate of vertically disposed pores. This work indicates practical benefits in the use of slotted membranes over conventional methods.

关键词： Membrane emulsification Slotted pore Tubular membrane Rotating emulsification Size control High throughput

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