bluuebunny/crossref_metadata_2025_split huggingface dataset:
What Comes First? Multitissue Involvement Leading to Radiographic Osteoarthritis: Magnetic Resonance Imaging–Based Trajectory Analysis Over Four Years in the Osteoarthritis Initiative
Authors: Roemer Frank W. , Kwoh C. Kent , Hannon Michael J. , Hunter David J. , Eckstein Felix , Fujii Tomoko , Boudreau Robert M. , Guermazi Ali 
Published: May 2015

ObjectiveTo assess whether the presence of structural osteoarthritis (OA) features over as many as 4 years prior to incident radiographic OA increases the risk of radiographic OA in a nested, case–control design.MethodsWe studied 355 knees from the Osteoarthritis Initiative cohort that developed radiographic OA before the 48‐month visit. They were matched one‐to‐one by sex, age, and contralateral knee radiographic status with a control knee. Magnetic resonance images (MRIs) were read for bone marrow lesions (BMLs), cartilage damage, meniscal damage (including tears and extrusion), Hoffa synovitis, and effusion synovitis. Conditional logistic regression was applied to assess the risk of radiographic OA with regard to the presence of BMLs (score ≥2), cartilage lesions (score ≥1.1), meniscal damage (any) and extrusion of ≥3 mm ± (score ≥2), and Hoffa and effusion synovitis (any). Time points were defined as incident radiographic OA visit (P0), 1 year prior to the detection of radiographic OA (P −1), 2 years prior to the detection of radiographic OA (P −2), etc.ResultsThe presence of Hoffa synovitis (hazard ratio [HR] 1.76 [95% confidence interval (95% CI) 1.18–2.64]), effusion synovitis (HR 1.81 [95% CI 1.18–2.78]), and medial meniscal damage (HR 1.83 [95% CI 1.17–2.89]) at P −2 predicted radiographic OA incidence. At P −1, all features but meniscal extrusion predicted radiographic OA, with highest odds for medial BMLs (HR 6.50 [95% CI 2.27–18.62]) and effusion synovitis (HR 2.50 [95% CI 1.76–3.54]). The findings at P −3 and P −4 did not reach statistical significance.ConclusionOur findings indicate that the presence of specific structural features of MRI‐detected joint damage 2 years prior to incident radiographic OA increases the risk of incident radiographic OA. However, 1 year prior to radiographic OA, the presence of almost any abnormal morphologic feature increases the risk of radiographic OA in the subsequent year.
Genome‐Wide Mapping of DNA Hydroxymethylation in Osteoarthritic Chondrocytes
Authors: Taylor Sarah E. B. , Li Ye Henry , Wong Wing H. , Bhutani Nidhi 
Published: May 2015

ObjectiveTo examine the genome‐wide distribution of hydroxymethylated cytosine (5hmC) in osteoarthritic (OA) and normal chondrocytes in order to investigate the effect on OA‐specific gene expression.MethodsCartilage was obtained from OA patients undergoing total knee arthroplasty or from control patients undergoing anterior cruciate ligament reconstruction. Genome‐wide sequencing of 5hmC‐enriched DNA was performed in a small cohort of normal and OA chondrocytes to identify differentially hydroxymethylated regions (DhMRs) in OA chondrocytes. Data from the genome‐wide sequencing of 5hmC‐enriched DNA were intersected with global OA gene expression data to define subsets of genes and pathways potentially affected by increased 5hmC levels in OA chondrocytes.ResultsA total of 70,591 DhMRs were identified in OA chondrocytes as compared to normal chondrocytes, 44,288 (63%) of which were increased in OA chondrocytes. The majority of DhMRs (66%) were gained in gene bodies. Increased DhMRs were observed in ∼50% of genes previously implicated in OA pathology including MMP3, LRP5, GDF5, and COL11A1. Furthermore, analyses of gene expression data revealed gene body gain of 5hmC appears to be preferentially associated with activated, but not repressed, genes in OA chondrocytes.ConclusionThis study provides the first genome‐wide profiling of 5hmC distribution in OA chondrocytes. We had previously reported a global increase in 5hmC levels in OA chondrocytes. Gain of 5hmC in the gene body is found to be characteristic of activated genes in OA chondrocytes, highlighting the influence of 5hmC as an epigenetic mark in OA. In addition, this study identifies multiple OA‐associated genes that are potentially regulated either singularly by gain of DNA hydroxymethylation or in combination with loss of DNA methylation.
Mitochondrial Biogenesis Is Impaired in Osteoarthritis Chondrocytes but Reversible via Peroxisome Proliferator–Activated Receptor γ Coactivator 1α
Authors: Wang Yun , Zhao Xianling , Lotz Martin , Terkeltaub Robert , Liu‐Bryan Ru 
Published: May 2015

ObjectiveThe etiology of chondrocyte mitochondrial dysfunction in osteoarthritis (OA) is not completely understood. OA chondrocytes are deficient in the metabolic biosensors active AMP‐activated protein kinase (AMPK) and sirtuin 1 (SIRT‐1), which modulate the mitochondrial biogenesis “master regulator” peroxisome proliferator–activated receptor γ coactivator 1α (PGC‐1α). Moreover, PGC‐1α critically mediates AMPK anticatabolic activity in chondrocytes. The aim of this study was to test the hypothesis that mitochondrial biogenesis is deficient in human OA chondrocytes and that this deficiency functionally increases chondrocyte procatabolic responses, which are reversed by activation of the AMPK/SIRT‐1/PGC‐1α pathway.MethodsWe assessed the expression and activity (phosphorylation) of AMPKα, SIRT‐1, and PGC‐1α in human knee chondrocytes and human and mouse knee cartilage, and we defined and compared the content and function of mitochondria, including oxidative phosphorylation and expression of mitochondrial biogenesis factors (mitochondrial transcriptional factor A [TFAM] and nuclear respiratory factors [NRFs]).ResultsHuman knee OA chondrocytes had a decreased mitochondrial biogenesis capacity, which was linked to reduced AMPKα activity and decreased expression of SIRT‐1, PGC‐1α, TFAM, NRF‐1, and NRF‐2. Human knee OA and aging mouse knee cartilage had decreased expression of TFAM and ubiquinol–cytochrome c reductase core protein, a subunit of mitochondrial complex III, in situ. Chondrocyte TFAM knockdown inhibited mitochondrial biogenesis and enhanced procatabolic responses to interleukin‐1β. Finally, activation of AMPK by A‐769662 increased PGC‐1α expression via SIRT‐1 and reversed impairments in mitochondrial biogenesis, oxidative phosphorylation, and intracellular ATP in human knee OA chondrocytes.ConclusionMitochondrial biogenesis is deficient in human OA chondrocytes, and this deficiency promotes chondrocyte procatabolic responses. TFAM‐mediated activation of the AMPK/SIRT‐1/PGC‐1α pathway reverses these effects, suggesting translational potential of pharmacologic AMPK activators to limit OA progression.
Clinical Characterization of Antiphospholipid Syndrome by Detection of IgG Antibodies Against β2‐Glycoprotein I Domain 1 and Domain 4/5: Ratio of Anti–Domain 1 to Anti–Domain 4/5 As a Useful New Biomarker for Antiphospholipid Syndrome
Authors: Andreoli Laura , Chighizola Cecilia B. , Nalli Cecilia , Gerosa Maria , Borghi M. Orietta , Pregnolato Francesca , Grossi Claudia , Zanola Alessandra , Allegri Flavio , Norman Gary L. , Mahler Michael , Meroni Pier Luigi , Tincani Angela 
Published: May 2015

ObjectiveIt has been suggested that only antibodies against domain 1 (D1) of β2‐glycoprotein I (β2GPI) are pathogenic and diagnostic. The role of antibodies against other β2GPI domains is still debated. This study was undertaken to evaluate the clinical relevance of domain specificity profiling of anti‐β2GPI IgG antibodies in antiphospholipid syndrome (APS) patients and in control groups of patients with systemic autoimmune rheumatic diseases and in asymptomatic antiphospholipid antibody (aPL) carriers.MethodsWe evaluated 159 subjects with persistently positive, medium or high‐titer anti‐β2GPI IgG, including 56 patients with thrombotic (obstetric or nonobstetric) primary APS, 31 women with obstetric primary APS, 42 aPL‐positive patients with systemic autoimmune rheumatic diseases, and 30 asymptomatic aPL carriers. One hundred healthy donors were included. Anti‐β2GPI D1 and D4/5 IgG were tested on research enzyme‐linked immunosorbent assays containing recombinant β2GPI domains.ResultsAs compared to other groups, aPL carriers displayed higher frequency/titer of anti‐D4/5 IgG. Unlike anti‐D4/5, anti‐D1 IgG antibodies were more frequent and at higher titer in triple than in single or double aPL‐positive subjects. An anti‐D1 to anti‐D4/5 ratio of ≥1.5 was predictive of systemic autoimmunity (odds ratio 3.25 [95% confidence interval 1.45–7.49], P = 0.005). Neither anti‐D1 nor anti‐D4/5 antibodies were associated with APS clinical criteria.ConclusionAnti‐D1 IgG is the preferential specificity not only in vascular and obstetric primary APS, but also in patients with systemic autoimmune rheumatic disease with no clinical features of APS. Conversely, aPL carriers do not have a polarized profile toward D1. Combined testing for anti‐β2GPI IgG with different domain specificity allows a more accurate aPL profiling, with polarization toward anti‐D1 IgG as a possible fingerprint of systemic autoimmunity.
Observations of fire‐induced turbulence regimes during low‐intensity wildland fires in forested environments: implications for smoke dispersion
Authors: Heilman Warren E. , Clements Craig B. , Seto Daisuke , Bian Xindi , Clark Kenneth L. , Skowronski Nicholas S. , Hom John L. 
Published: May 2015

AbstractLow‐intensity wildland fires occurring beneath forest canopies can result in particularly adverse local air‐quality conditions. Ambient and fire‐induced turbulent circulations play a substantial role in the transport and dispersion of smoke during these fire events. Recent in situ measurements of fire–atmosphere interactions during low‐intensity wildland fires have provided new insight into the structure of fire‐induced turbulence regimes and how forest overstory vegetation can affect the horizontal and vertical dispersion of smoke. In this paper, we provide a summary of the key turbulence observations made during two low‐intensity wildland fire events that occurred in the New Jersey Pine Barrens.
Zum Trag‐ und Erwärmungsverhalten von Verbundstützen mit massivem Stahlkern im Brandfall
Authors: Schaumann Peter , Kleibömer Inka 
Published: May 2015

AbstractAusbetonierte Hohlprofilstützen mit massiven Einstellprofilen stellen eine attraktive Möglichkeit dar, schlanke Stützen auch bei hohen Lasten zu realisieren und gleichzeitig hohe Anforderungen an den Feuerwiderstand zu erfüllen. Das Tragverhalten im Brandfall unterscheidet sich dabei grundlegend von dem anderer ausbetonierter Hohlprofilstützen, die bei gleicher Querschnittsfläche deutlich geringere Lasten abtragen. Dieser Beitrag behandelt Ergebnisse eines Forschungsprojektes, in dem das Tragverhalten einer runden Verbundstütze mit massivem Stahlkern im Brandfall experimentell untersucht wurde. Nach Erreichen der Feuerwiderstandsklasse R 90 wurde die Stütze bis zum Erreichen der Traglast belastet. Im Zuge der Untersuchungen wurde die Entwicklung der Temperaturen im Querschnitt ermittelt und den Ergebnissen numerisch ermittelter Temperaturfeldberechnungen gegenübergestellt.Thermal and structural response of concrete‐filled tubular columns with massive steel core in case of fireConcrete‐filled tubular columns with embedded massive steel core represent an attractive constructional possibility to design slender columns that are both resisting high loads and fulfil requirements concerning the fire resistance. The structural behaviour in case of fire thereby differs from the typical behaviour of concrete‐filled tubular columns without steel core, which carry remarkably lower loads. In the following paper, the thermal and mechanical behaviour of a circular composite column with embedded massive steel core is investigated experimentally. After achieving the fire resistance class R 90, the column was loaded up to failure and thus the residual bearing capacity was ascertained. Furthermore, the measurement of temperatures within the individual parts of the cross‐section was another aspect of the experimental investigations. Those data are additionally compared to numerically calculated temperatures.
Interaktionen zwischen Abdichtungsbauwerk und Wirtsgestein im Steinsalz
Authors: Stahlmann Joachim , Missal Christian , Gährken Andreas 
Published: May 2015

AbstractBei der Planung von Tiefen‐ oder Endlagern für radioaktive Abfälle wird angestrebt, den Zutritt von Wässern oder Lösungen langfristig zu verhindern, um das Schutzziel über Tage zu erreichen. Da im Fall einer Worst‐case‐Betrachtung der Zutritt nicht vollständig ausgeschlossen werden kann, sind die Zugangsstrecken zu den Einlagerungsbereichen abzudichten. Die Funktion wird im Wesentlichen durch die Interaktion zwischen Wirtsgestein und Abdichtungsbauwerk bestimmt. Insbesondere sind die Auflockerungszone im konturnahen Bereich, die Kontaktzone, Spannungsumlagerungen im Gebirge sowie die Kriecheigenschaften des Gebirges abdichtungsrelevant. Zusätzlich sind die Baustoffeigenschaften des Dammes zu berücksichtigen: Die Abkühlphase nach dem Abbindeprozess und autogenes Schwinden führen zu einer Spaltbildung zwischen Abdichtungsbauwerk und Wirtsgestein. Dieser Spalt ist für die kurzfristige Funktionsfähigkeit zu verpressen, langfristig kann das aufkriechende Gebirge eine ausreichend geringe Permeabilität gewährleisten. Es zeigt sich jedoch, dass die Übertragbarkeit der Modellvorstellungen aus dem Erfahrungshorizont des Bergbaus und des Bauingenieurwesens, auch im Hinblick auf die möglichen Fluidwegigkeiten, noch zu hinterfragen ist.Interaction between sealing structure and host rock in rock saltDuring the development of radioactive waste disposal it is intended to prevent the inflow of water and solution over a long period of time to reach the safety objective at the surface. As the inflow cannot be completely excluded when considering a worst case scenario, the access drifts towards the emplacement chambers have to be sealed. This function is primarily influenced by the interaction between the host rock and the sealing structure. The excavation damaged zone close to the contour, contact zone, stress redistribution in the host rock and the creeping capacity of the host rock are particularly relevant for the sealing. In addition, the characteristics of the sealing structure's building materials have to be considered: the cooling phase after the setting process and autogenous shrinkage lead to the development of gaps between the sealing structure and the host rock. These gaps have to be injected in order to reach a short‐term operability, while the long‐term low permeability can be provided by the creeping host rock. It became clear that the portability of the model concepts based on the experiences in mining and civil engineering have to be questioned, especially with regards to possible fluid flow.
Thermische Einwirkungen natürlicher Brände auf Bauteile und Tragwerke
Authors: Riese Olaf , Zehfuß Jochen 
Published: May 2015

AbstractDie außergewöhnliche Bemessungssituation Brand als Lasteinwirkung auf Bauteile und Tragwerke ist in DIN EN 1991‐1‐2:2010‐12, Eurocode 1: Einwirkungen auf Tragwerke – Teil 1‐2: Allgemeine Einwirkungen – Brandeinwirkungen auf Tragwerke geregelt. Im zugehörigen Nationalen Anhang DIN EN 1991‐1‐2/NA werden die national festzulegenden Parameter bzw. nationale Festlegungen sowie die Anwendung informativer Anhänge für Deutschland definiert. Neben der Einheits‐Temperaturzeitkurve (ETK) als standardisierte thermische Einwirkung werden in DIN EN 1991‐1‐2 und zugehörigem Nationalen Anhang auch Naturbrandmodelle geregelt, mit denen die thermischen Einwirkungen leistungsorientiert in Abhängigkeit der vorhandenen Brandlasten, Ventilationsverhältnisse, Brandraumgeometrie und thermischen Eigenschaften der Umfassungsbauteile berechnet werden können. In der Musterliste der Technischen Baubestimmungen von März 2014 werden Randbedingungen für die Anwendung der Naturbrandverfahren beschrieben. Im Rahmen dieses Aufsatzes werden die zur Ermittlung der thermischen Einwirkung mit Naturbrandmodellen zugrunde zu legenden Brandszenarien und Bemessungsbrände dargestellt und auf deren Eignung und sinnvollen Anwendungsbereich eingegangen.Thermal actions of components and structures exposed to natural firesThe exceptional case of fire load on construction parts and structures as action for building components is regulated by DIN EN 1991‐1‐2: 2010‐12, Eurocode 1: Actions on structures – Part 1‐2: General actions – fire actions on structures. In the National Annex DIN EN 1991‐1‐2/NA the national determined parameters and national requirements as well as the application of informative annex for Germany are defined. The DIN EN 1991‐1‐2 and the associated National Annex regulate the standard temperature‐time curve (ETK) as standardized thermal load and furthermore natural fire models which can be used for performance based fires safety design considering the actual fire loads, ventilation conditions, geometry of fire room and thermal properties of the structural components. In the Musterliste der Technischen Baubestimmungen of March 2014 boundary conditions are described for the application of natural fire method. This paper shows fire scenarios and design fires for determination of the thermal load with natural fire models and their suitability and practicable application.
Vorspannung bei Onshore‐Windenergieanlagen
Authors: Gläser Christian , Puttendörfer Niklas , Brockmann Sven , Hartwig Thomas 
Published: May 2015

AbstractMit steigender Bedeutung der Windkraft und Weiterentwicklung der Turbinen werden höhere Türme für Windenergieanlagen erforderlich. Verbunden damit ergeben sich Änderungen in der Bauweise der Türme. Abhängig vom verwendeten Turmtyp werden die Fundamente unterschiedlich ausgebildet. Bei Stahltürmen werden Stahlteile oder vorgespannte Ankerbolzen einbetoniert, während für den Beton‐Beton‐Anschluss bei Spannbeton‐ und Hybridtürmen andere vorgespannte Lösungen Anwendung finden. Bis vor wenigen Jahren kamen in Deutschland bei vorgespannten Türmen nur Spannglieder mit nachträglichem Verbund zum Einsatz. Weiterentwicklungen haben dazu geführt, dass jetzt auch weltweit Spannbeton‐ und Hybridtürme mit externen Spanngliedern vorgespannt werden. Auch wenn der grundsätzliche Aufbau der Spannglieder ähnlich wie im Brückenbau sein kann, muss die Anwendbarkeit für die abweichenden Randbedingungen im Turm einer Windenergieanlage nachgewiesen sein.Bei der Vielzahl der weltweit ausgeführten Anlagen ist es nicht ausgeblieben, dass aufgrund von Ausführungsfehlern oder während der Bemessung nicht berücksichtigter Erkenntnisse die Verstärkung vorhandener Konstruktionen erforderlich werden kann. Im vorliegenden Artikel wird die Instandsetzung eines Fundaments beschrieben, bei dem infolge ursprünglich zu niedriger Betonfestigkeit durch die Umschnürung des Fundaments mittels Spanngliedern aktiv ein dreiaxialer Spannungszustand erzeugt wird, der die vertikale Druckfestigkeit des Fundaments erhöht.Post‐Tensioning for Onshore‐Wind Energy Plants – From New Construction to retrofitting of existing structuresWith increasing importance of wind power and development of stronger turbines higher towers for wind energy are required. Related to this, changes in the design of the towers are necessary. Depending on the used tower type foundations are designed differently. While in a steel tower steel parts or bolts are cast in the concrete, prestressed solutions can be used for the concrete‐concrete connection in post‐tensioned concrete and hybrid towers. While a few years ago in Germany only bonded tendons were used for post‐tensioned towers, further developments have globally led to stressing concepts using external tendons in post‐tensioned concrete and hybrid towers. Although the basic layout of the tendons may be similar to tendons used in bridge construction, the applicability of the different boundary conditions in the wind‐tower has to be verified.With the multitude of running plants it cannot completely be prevented that failures during execution or factors not considered during design makes it necessary to strengthen existing towers. In this article, retrofitting of a foundation is described in which due to originally lower concrete strength by the confinement of the foundation an actively triaxial stress state is generated by tendons, which increases the vertical compressive strength of the foundation.
Stabilitätsverhalten von schlanken Wandscheiben aus Normal‐ und Ultrahochleistungsbeton
Authors: Lechner Thomas , Fischer Oliver 
Published: May 2015

AbstractDie Entwicklung und Erforschung des Ultrahochleistungsbetons hat dazu geführt, dass es heute vorteilhaft ist, viele klassische Betonbauteile aus diesem innovativen Werkstoff herzustellen. Für Wandscheiben bedeutet dies, dass sich die Dicke aufgrund der hohen Druckfestigkeit reduzieren lässt, während sich die Dauerhaftigkeit infolge der geringen Porosität erhöht. Da Wandscheiben aus Ultrahochleistungsbeton im Vergleich zu Wänden aus Normalbeton bei gleicher Querschnittstragfähigkeit deutlich größere Schlankheiten aufweisen können, gewinnt das Stabilitätsverhalten entsprechend an Bedeutung. Der vorliegende Beitrag beschreibt Untersuchungen zum Stabilitätsverhalten von Wandscheiben, die am Lehrstuhl für Massivbau der Technischen Universität München (TUM) durchgeführt wurden. Der Forschungsschwerpunkt lag dabei auf zweiseitig gehaltenen Scheiben aus unbewehrtem Normalbeton sowie faserbewehrtem Ultrahochleistungsbeton. An diesen wurden experimentelle und numerische Untersuchungen zum Trag‐ und Verformungsverhalten durchgeführt. Nachfolgend werden die Ergebnisse dieser Untersuchungen sowie ein Ingenieurmodell zur Berechnung der maßgebenden Stabilitätslasten von schlanken, zweiseitig gehaltenen Scheiben vorgestellt.Load bearing behavior and stability of slender wall panels made of normal strength and ultra‐high performance concrete.Following more than one decade of theoretical and experimental research on ultra‐high performance concrete (UHPC) today there is a series of possible applications to efficiently utilize this new and innovative material in load‐bearing structures. One example are walls and wall panels respectively, the thickness of which may be decisively reduced thanks to the high compressive strength, leading to increasingly slender structures being more sensitive in terms of stability. The present paper describes theoretical and experimental investigations on the load‐bearing and buckling behavior of normal strength and UHPC wall panels being currently performed at the chair of concrete and masonry structures of TUM. In doing so, exemplary results of these investigations are presented and discussed and an engineering model determining critical loads of slender walls is derived.