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Critical minimum temperature limits xylogenesis and maintains treelines on the southeastern Tibetan Plateau

science Bulletin 2017年第11期62卷 804-812页

作者： Xiaoxia Li Eryuan Liang Jozica Gricar sergio Rossi Katarina Cufar aaron M. Ellison Key Laboratory of Alpine Ecology and Biodiversity Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100101 China CAs Center for Excellence in Tibetan Plateau Earth sciences Beijing 100101 China sloven ian Forestry Institute Department of Yield and Silviculture Vecna pot 2 S1-1000 Ljubljana Slovenia University of Quebec in Chicoutimi Departement des Sciences Fondamentales 555 Boulevard de l'Universite Chicoutimi (QC) G7H2B1 Canada Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems Guangdong Provincial Key Laboratory of Applied Botany South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 China University of Ljubljana Biotechnical Faculty Department of Wood Science and Technology Jamnikarjeva 101 S1-1000 Ljubljana Slovenia Harvard Forest Harvard University 324 North Main St. Petersham MA 01366 USA

Physiological and ecological mechanisms that define treelines are still debated. It has been suggested that the absence of trees above the treeline is caused by low temperatures that limit growth. Thus, we hypothesized that there is a critical minimum temperature （CTmin） preventing xylogenesis at treeline. We tested this hypothesis by examining weekly xylogenesis across three and four growing seasons in two natural smith fir （Abies georgei var. srnithii） treeline sites on the southeastern Tibetan Plateau. Despite differences in the timing of cell differentiation among years, minimum air temperature was the dominant climatic variable associated with xylem growth; the critical minimum temperature （CTmin） for the onset and end of xylogenesis occurred at 0.7 ±0.4 ℃. A process-based modelling chronology of tree-ring formation using this CTmin was consistent with actual tree-ring data. This extremely low CTmin permits smith fir growing at treeline to complete annual xylem production and maturation and provides both support and a mechanism for treeline formation.

关键词： Cambial activity Critical minimum temperature Timberline Xylem Vaganov-shashldn model

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Effects of glucagon-like peptide-1 receptor agonists on non-alcoholic fatty liver disease and inflammation

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World Journal of Gastroenterology 2014年第40期20卷 14821-14830页

作者： Xing-Chun Wang aaron M Gusdon Huan Liu shen Qu Department of Endocrinology and Metabolism Shanghai 10th People’s Hospital Tongji University Nanjing Medical University Department of Neurology and Neuroscience Weill Cornell Medical College New York NY 10065 United States

Glucagon-like peptide1 (GLP-1) is secreted from Langerhans cells in response to oral nutrient intake. Glucagon- like peptide-1 receptor agonists (GLP-1RAs) are a new class of incretin-based anti-diabetic drugs. They function to stimulate insulin secretion while suppressing glucagon secretion. GLP-1-based therapies are now well established in the management of type 2 diabetes mellitus (T2DM), and recent literature has suggested potential applications of these drugs in the treatment of obesity and for protection against cardiovascular and neurological diseases. As we know, along with change in lifestyles, the prevalence of non-alcoholic fatty liver disease (NAFLD) in China is rising more than that of viral hepatitis and alcoholic fatty liver disease, and NAFLD has become the most common chronic liver disease in recent years. Recent studies further suggest that GLP-1RAs can reduce transaminase levels to improve NAFLD by improving blood lipid levels, cutting down the fat content to promote fat redistribution, directly decreasing fatty degeneration of the liver, reducing the degree of liver fibrosis and improving inflammation. This review shows the NAFLD-associated effects of GLP-1RAs in animal models and in patients with T2DM or obesity who are participants in clinical trials. (C) 2014 Baishideng Publishing Group Inc. All rights reserved.

关键词： Glucagon-like peptide-1 receptor agonists Liver function Fat content Non-alcoholic fatty liver disease Inflammation

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Convergent synaptic and circuit substrates underlying autism genetic risks

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Frontiers in Biology 2014年第2期9卷 137-150页

作者： aaron MCGEE Guohui LI Zhongming LU shenfeng QIU Developmental Neuroscience Program Saban Research Institute Children's Hospital Los Angeles Department of Pediatrics Keck Schoolof Medicine University of Southern California Los Angeles CA 90027 USA Interdisciplinary Graduate Program in Neuroscience School of Life Science Arizona State University Tempe AZ 85287 USA Department of Basic Medical sciences University of Arizona College of Medicine-Phoenix Phoenix AZ 85004 USA

There has been a surge of diagnosis of autism spectrum disorders （AsD） over the past decade. While large, high powered genome screening studies of children with AsD have identified numerous genetic risk factors, research efforts to understanding how each of these risk factors contributes to the development autism has met with limited success. Revealing the mechanisms by which these genetic risk factors affect brain development and predispose a child to autism requires mechanistic understanding of the neurobiological changes underlying this devastating group of developmental disorders at multifaceted molecular, cellular and system levels. It has been increasingly clear that the normal trajectory of neurodevelopment is compromised in autism, in multiple domains as much as aberrant neuronal production, growth, functional maturation, patterned connectivity, and balanced excitation and inhibition of brain networks. Many autism risk factors identified in humans have been now reconstituted in experimental mouse models to allow mechanistic interrogation of the biological role of the risk gene. studies utilizing these mouse models have revealed that underlying the enormous heterogeneity of perturbed cellular events, mechanisms directing synaptic and circuit assembly may provide a unifying explanation for the pathophysiological changes and behavioral endophenotypes seen in autism, although synaptic perturbations are far from being the only alterations relevant for AsD. In this review, we discuss synaptic and circuit abnormalities obtained from several prevalent mouse models, particularly those reflecting syndromic forms of AsD that are caused by single gene perturbations. These compiled results reveal that AsD risk genes contribute to proper signaling of the developing gene networks that maintain synaptic and circuit homeostasis, which is fundamental to normal brain development.

关键词： autism spectrum disorders development risk genes synapse circuits behavior neurodevelopmental disorders

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Ectomycorrhizal and saprotrophic Fungal Communities Vary Across mm-scale soil Microsites Differing in Phosphatase Activity

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Pedosphere 2019年第3期29卷 344-359页

作者： aaron GODIN Denise BROOKs sue J. GRAYsTON Melanie D. JONEs Biology Department University of British Columbia Okanagan campus Kelowna V1V 1V7 (Canada) Department of Forest & Conservation sciences Faculty of Forestry University of British Columbia Vancouver V6T 1Z4 (Canada)

To understand nutrient cycling in soils, soil processes and microorganisms need be better characterized. To determine whether specific trophic groups of fungi are associated with soil enzyme activity, we used soil imprinting to guide mm-scale sampling from microsites with high and low phosphatase activities in birch/Douglas-fir stands. study 1 involved sampling one root window per site at 12 sites of different ages(stands);study 2 was conducted at one of the stem-exclusion stands, at which 5 root windows had been installed. Total fungal and ectomycorrhizal(EM) fungal terminal-restriction fragment length polymorphism(TRFLP)fingerprints differed between high-and low-phosphatase activity microsites at 8 of 12 root windows across 12 sites. Where differences were detected, fewer EM fungi were detected in high-than low-phosphatase activity microsites. Using 5 root windows at one site,next-generation sequencing detected similar fungal communities across microsites, but the ratio of saprotrophic to EM fungal reads was higher in high-phosphatase activity microsites in the two windows that had low EM fungal richness. In windows with differences in fungal communities, both studies indicated that EM fungi were less successful than saprotrophic fungi in colonizing fine-scale,organic matter-rich microsites. Fine-scale sampling linked with in situ detection of enzyme activity revealed relationships between soil fungal communities and phosphatase activity that could not be observed at the scales employed by conventional approaches, thereby contributing to the understanding of fine-scale phosphorus cycling in forest soils.

关键词： ectomycorrhizae fine scale fungal communities phosphatase root windows saprotrophic fungi soil imprinting

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Broadband achromatic dielectric metalenses

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Light(science & Applications) 2018年第1期7卷 236-246页

作者： sajan shrestha Adam C.Overvig Ming Lu aaron stein Nanfang Yu Department of Applied Physics and Applied Mathematics Columbia UniversityNew YorkNY 10027USA Brookhaven National Laboratory Center for Functional NanomaterialsUptonNY 11973USA

Metasurfaces offer a unique platform to precisely control optical wavefronts and enable the realization of flat lenses,or metalenses,which have the potential to substantially reduce the size and complexity of imaging systems and to realize new imaging ***,it is a major challenge to create achromatic metalenses that produce a single focal length over a broad wavelength range because of the difficulty in simultaneously engineering phase profiles at distinct wavelengths on a single *** practical applications,there is a further challenge to create broadband achromatic metalenses that work in the transmission mode for incident light waves with any arbitrary polarization *** developed a design methodology and created libraries of meta-units—building blocks of metasurfaces—with complex cross-sectional geometries to provide diverse phase dispersions(phase as a function of wavelength),which is crucial for creating broadband achromatic *** elucidated the fundamental limitations of achromatic metalens performance by deriving mathematical equations that govern the tradeoffs between phase dispersion and achievable lens parameters,including the lens diameter,numerical aperture(NA),and bandwidth of achromatic *** experimentally demonstrated several dielectric achromatic metalenses reaching the fundamental *** metalenses work in the transmission mode with polarization-independent focusing efficiencies up to 50%and continuously provide a near-constant focal length over λ=1200–1650 *** unprecedented properties represent a major advance compared to the state of the art and a major step toward practical implementations of metalenses.

关键词： chromatic dielectric limitations

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Evaluation and management of inherited disorders of surfactant metabolism

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Chinese Medical Journal 2010年第20期123卷 2943-2947页

作者： aaron Hamvas Edward Mallinckrodt Department of Pediatrics Washington University School of Medicine and St. Louis Children's Hospital St. Louis Missouri 63110 USA

Objective To review the pathophysiology, evaluation, management, and outcomes of children with inherited disorders of surfactant metabolism due to mutations in the genes encoding surfactant proteins-B or -C（sFTPB, sFTPC）, ATP binding cassette member A3 （ABCA3）, and thyroid transcription factor （NKX2.1）.Data sources Review of the literature, previous work from the author＇s and collaborators＇ laboratories, st. Louis Children＇s Hospital Lung Transplant *** selection Key articles in the field, author＇s *** Inherited disorders of surfactant metabolism present as acute, severe respiratory dysfunction in the neonatal period （sFTPB, ABCA3, NKX2.1） or as chronic respiratory insufficiency in later infancy and childhood which is of variable onset, severity, and course （sFTPC, ABCA3, NKX2.1）. Diagnosis is established with sequencing the relevant genes; lung biopsy with electron microscopy is a useful adjunct. For surfactant protein-B and ABCA3 deficiency presenting with acute neonatal disease, treatment options are limited to lung transplantation or compassionate care. For the more chronic presentations of surfactant protein-C, ABCA3, and NKX2.1 associated disease, the natural history is variable and therefore individualized, supportive care is appropriate,Conclusions Inherited disorders of surfactant metabolism are rare, but informative diseases that provide unique opportunities for understanding mechanisms of respiratory disease in newborns and children.

关键词： respiratory distress syndrome newborn genetics lung transplantation

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Exposure to dietary mercury alters cognition and behavior of zebra finches

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Current Zoology 2017年第2期63卷 213-219页

作者： John R sWADDLE Tessa R. DIEHL Capwell E, TAYLOR aaron s. FANAEE Jessica L. BENsON Neil R. HUCKsTEP Daniel A. CRIsTOL Biology Department College of William and Mary Institute for Integrative Bird Behavior Studies Williamsburg VA 23187-8795 USA Biological sciences Virginia Tech 1405 Perry Street Blacksburg VA 24061 USA

Environmental stressors can negatively affect avian cognitive abilities, potentially reducing fitness, for example by altering response to predators, display to mates, or memory of locations of food. We expand on current knowledge by investigating the effects of dietary mercury, a ubiquitous en- vironmental pollutant and known neurotoxin, on avian cognition. Zebra finches Taeniopygia gut- tata were dosed for their entire lives with sub-lethal levels of mercury, at the environmentally rele- vant dose of 1.2 parts per million. In our first study, we compared the dosed birds with controls of the same age using tests of three cognitive abilities： spatial memory, inhibitory control, and color association. In the spatial memory assay, birds were tested on their ability to learn and remember the location of hidden food in their cage. The inhibitory control assay measured their ability to ig- nore visible but inaccessible food in favor of a learned behavior that provided the same reward. Finally, the color association task tested each bird＇s ability to associate a specific color with the presence of hidden food. Dietary mercury negatively affected spatial memory ability but not inhibi- tory control or color association. Our second study focused on three behavioral assays not tied to a specific skill or problem-solving： activity level, neophobia, and social dominance. Zebra finches exposed to dietary mercury throughout their lives were subordinate to, and more active than, con- trol birds. We found no evidence that mercury exposure influenced our metric of neophobia. Together, these results suggest that sub-lethal exposure to environmental mercury selectively harms neurological pathways that control different cognitive abilities, with complex effects on be- havior and fitness.

关键词： animal behavior ecotoxicology cognition mercury spatial memory zebra finch.

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Magnetically controlled growing instrumentation for early onset scoliosis: Caution needed when interpreting the literature

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World Journal of Orthopedics 2019年第11期10卷 394-403页

作者： Kenneth aaron shaw Justin M Hire scott Kim Dennis P Devito Michael L schmitz Joshua s Murphy Department of Orthopaedic surgery Dwight D.Eisenhower Army Medical CenterFort GordonGA 30905United States Department of Orthopaedic surgery General Leonard Wood Army Community HospitalFort Leonard WoodMO 65473United States University of Tennessee Health science Center MemphisTN 38163United States Department of Pediatric Orthopaedic surgery Children’s Healthcare of AtlantaScottish Rite CampusAtlantaGA 30342United States

BACKGROUND Magnetically controlled growing rods(MCGR) are a novel treatment option for early onset scoliosis(EOs). Although the complication profile with MCGR use has been reviewed, these reviews do not take into account important implants modifications, termed iterations, that were made due to early on postoperative complications is not well reported or *** To assess the effect of MCGR implant iterations on post-operative complications in *** A systematic review was performed to identify studies investigating MCGR specifically for the treatment of EOs, refined to those reporting the implant iteration, specifically the incorporation of the keeper plate to the implant *** with mixed implant iteration usage were excluded. Complications following surgery were recorded as well as potential risk factors and compared between implant *** Although 20 articles were identified for inclusion, 5 included mixed implant iteration leaving a total of 271 patients identified through 15 clinical studies thatmet inclusion criteria. The average follow-up was 25.4-mo. Pre-keeper plate implants were utilized in 3 studies with a total of 49 patients. Overall, 115(42.4%)post-operative complications were identified, with 87% defined as major. The addition of the keeper plate significantly decreased the rate of post-operative complications per study(35.7% vs 80.6%, P = 0.036), and the rate of distraction failure(8.1% vs 40.8%, P = 0.02). Unplanned reoperation occurred in 69(26.7%)patients but was not different between implant iteration cohorts(25.5% without keeper plate vs 27.1% with keeper plate, P = 0.92).CONCLUsION MCGR for EOs has a cumulative complication rate of 42.4% but this is significantly reduced to 35.7% when reviewing only keeper-plate enabled implants. However, 25% of published articles included mixed implant *** studies should discern between implants iterations when reporting on the usage of MCGR for EOs.

关键词： Complications Early onset scoliosis Magnetically controlled growing instrumentations Keeper plate Reoperation systematic review

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共价有机骨架纳滤膜的制备和有机污染物去除研究

共价有机骨架纳滤膜的制备和有机污染物去除研究

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作者： aaron s Pittman 天津大学

学位级别：硕士

膜分离技术因其设备投资小、低能源消耗和稳定性能在水处理中发挥着重要作用。然而,分离膜固有的渗透性-选择性的权衡效应仍然是制约膜分离技术广泛应用的重大障碍。共价有机框架材料(COF)是一种高度稳定且完全由有机分子组成的结晶框... 详细信息

膜分离技术因其设备投资小、低能源消耗和稳定性能在水处理中发挥着重要作用。然而,分离膜固有的渗透性-选择性的权衡效应仍然是制约膜分离技术广泛应用的重大障碍。共价有机框架材料(COF)是一种高度稳定且完全由有机分子组成的结晶框架材料,其多样化结构特性引起科学家们的关注。目前,基于COFs纳滤膜的制备研究仍然缺乏简便而温和的方法。界面聚合(IP)过程是一种成熟的纳滤膜制备方法。因此,本研究尝试通过界面聚合过程制备高性能COFs纳滤膜,并研究其有机污染物的脱除过程。本研究采用界面聚合技术制备了一种具有高渗透通量和截留率的COFs纳滤膜。首先,实验采用1,2,3-三氨基胍盐酸盐(TAGH)为水相单体,2,5-二羟基对苯二甲醛(Dha)为有机相单体,通过界面聚合反应在聚砜(Psf)基膜表面成功制备出连续无缺陷的共价有机框架纳滤膜。实验采用傅里叶变换红外光谱(FTIR)、扫描电子显微镜(sEM)、X射线衍射仪(XRD)对COFs纳滤膜进行结构表征,分析COFs纳滤膜的化学组成、表面形貌和晶态结构,从而验证COFs选择层的成功制备。实验系统评价了COFs纳滤膜的渗透选择性能。采用制备的TAGH-Dha/Psf纳滤膜在25°C和3 bar的操作压力下对染料分子的水溶液进行分离,其渗透通量约为40.2L·m·h·bar,对CB-T和CR染料分子的截留率高于98%,AF的截留率为95.3%,MB的截留率为95%,AO7的截留率为89%。进而,采用制备的TAGH-Dha/Psf纳滤膜在25°C和3 bar的操作压力下对1000 ppm NasO溶液进行分离,其渗透通量为19.9 Lmh,NasO截留率为12.8%。与文献报道的COFs纳滤膜相比,制备的TAGH-Dha/Psf膜表现出较高的渗透通量和染料脱除性能。因此,本工作成功在多孔基底上制备具有良好渗透选择性能和稳定性能的COFs纳滤膜,在有机污染物去除方面具有一定的应用潜力。

关键词：共价有机骨架纳滤膜界面聚合染料去除

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Role of cytokines in inflammatory bowel disease

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World Journal of Gastroenterology 2008年第27期14卷 4280-4288页

作者： Fausto sanchez-Muoz aaron Dominguez-Lopez Jesus K Yamamoto-Furusho Inflammatory Bowel Disease Clinic Department of Gastroenterology Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán Vasco de Quiroga 15 colonia Sección XVI

Inflammatory bowel disease (IBD), which includes Crohn’s disease (CD) and ulcerative colitis (UC), rep- resents a group of chronic disorders characterized by inflammation of the gastrointestinal tract, typically with a relapsing and remitting clinical course. Mucosal mac- rophages play an important role in the mucosal im- mune system, and an increase in the number of newly recruited monocytes and activated macrophages has been noted in the inflamed gut of patients with IBD. Activated macrophages are thought to be major con- tributors to the production of inflammatory cytokines in the gut, and imbalance of cytokines is contributing to the pathogenesis of IBD. The intestinal inflammation in IBD is controlled by a complex interplay of innate and adaptive immune mechanisms. Cytokines play a key role in IBD that determine T cell differentiation of Th1, Th2, T regulatory and newly described Th17 cells. Cytokines levels in time and space orchestrate the development, recurrence and exacerbation of the inflammatory process in IBD. Therefore, several cyto- kine therapies have been developed and tested for the treatment of IBD patients.

关键词： Cytokines Inflammatory bowel disease Crohn's disease Ulcerative colitis Inflammation

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