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Search Results: 1 - 10 of 5519 matches for " Markus Rickert "
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Collagen Metabolism of Human Osteoarthritic Articular Cartilage as Modulated by Bovine Collagen Hydrolysates
Saskia Schadow, Hans-Christian Siebert, Günter Lochnit, Jens Kordelle, Markus Rickert, Jürgen Steinmeyer
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0053955
Abstract: Destruction of articular cartilage is a characteristic feature of osteoarthritis (OA). Collagen hydrolysates are mixtures of collagen peptides and have gained huge public attention as nutriceuticals used for prophylaxis of OA. Here, we evaluated for the first time whether different bovine collagen hydrolysate preparations indeed modulate the metabolism of collagen and proteoglycans from human OA cartilage explants and determined the chemical composition of oligopeptides representing collagen fragments. Using biophysical techniques, like MALDI-TOF-MS, AFM, and NMR, the molecular weight distribution and aggregation behavior of collagen hydrolysates from bovine origin (CH-Alpha?, Peptan? B 5000, Peptan? B 2000) were determined. To investigate the metabolism of human femoral OA cartilage, explants were obtained during knee replacement surgery. Collagen synthesis of explants as modulated by 0–10 mg/ml collagen hydrolysates was determined using a novel dual radiolabeling procedure. Proteoglycans, NO, PGE2, MMP-1, -3, -13, TIMP-1, collagen type II, and cell viability were determined in explant cultures. Groups of data were analyzed using ANOVA and the Friedman test (n = 5–12). The significance was set to p≤0.05. We found that collagen hydrolysates obtained from different sources varied with respect to the width of molecular weight distribution, average molecular weight, and aggregation behavior. None of the collagen hydrolysates tested stimulated the biosynthesis of collagen. Peptan? B 5000 elevated NO and PGE2 levels significantly but had no effect on collagen or proteoglycan loss. All collagen hydrolysates tested proved not to be cytotoxic. Together, our data demonstrate for the first time that various collagen hydrolysates differ with respect to their chemical composition of collagen fragments as well as by their pharmacological efficacy on human chondrocytes. Our study underscores the importance that each collagen hydrolysate preparation should first demonstrate its pharmacological potential both in vitro and in vivo before being used for both regenerative medicine and prophylaxis of OA.
Polymeric implant materials for the reconstruction of tracheal and pharyngeal mucosal defects in head and neck surgery
Rickert, Dorothee
GMS Current Topics in Otorhinolaryngology, Head and Neck Surgery , 2009,
Abstract: The existing therapeutical options for the tracheal and pharyngeal reconstruction by use of implant materials are described. Inspite of a multitude of options and the availability of very different materials none of these methods applied for tracheal reconstruction were successfully introduced into the clinical routine. Essential problems are insufficiencies of anastomoses, stenoses, lack of mucociliary clearance and vascularisation. The advances in Tissue Engineering (TE) offer new therapeutical options also in the field of the reconstructive surgery of the trachea. In pharyngeal reconstruction far reaching developments cannot be recognized at the moment which would allow to give a prognosis of their success in clinical application. A new polymeric implant material consisting of multiblock copolymers was applied in our own work which was regarded as a promising material for the reconstruction of the upper aerodigestive tract (ADT) due to its physicochemical characteristics. In order to test this material for applications in the ADT under extreme chemical, enzymatical, bacterial and mechanical conditions we applied it for the reconstruction of a complete defect of the gastric wall in an animal model. In none of the animals tested either gastrointestinal complications or negative systemic events occurred, however, there was a multilayered regeneration of the gastric wall implying a regular structured mucosa.In future the advanced stem cell technology will allow further progress in the reconstruction of different kind of tissues also in the field of head and neck surgery following the principles of Tissue Engineering.
Sphingolipids in Human Synovial Fluid - A Lipidomic Study
Marta Krystyna Kosinska, Gerhard Liebisch, Guenter Lochnit, Jochen Wilhelm, Heiko Klein, Ulrich Kaesser, Gabriele Lasczkowski, Markus Rickert, Gerd Schmitz, Juergen Steinmeyer
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0091769
Abstract: Articular synovial fluid (SF) is a complex mixture of components that regulate nutrition, communication, shock absorption, and lubrication. Alterations in its composition can be pathogenic. This lipidomic investigation aims to quantify the composition of sphingolipids (sphingomyelins, ceramides, and hexosyl- and dihexosylceramides) and minor glycerophospholipid species, including (lyso)phosphatidic acid, (lyso)phosphatidylglycerol, and bis(monoacylglycero)phosphate species, in the SF of knee joints from unaffected controls and from patients with early (eOA) and late (lOA) stages of osteoarthritis (OA), and rheumatoid arthritis (RA). SF without cells and cellular debris from 9 postmortem donors (control), 18 RA, 17 eOA, and 13 lOA patients were extracted to measure lipid species using electrospray ionization tandem mass spectrometry - directly or coupled with hydrophilic interaction liquid chromatography. We provide a novel, detailed overview of sphingolipid and minor glycerophospholipid species in human SF. A total of 41, 48, and 50 lipid species were significantly increased in eOA, lOA, and RA SF, respectively when compared with normal SF. The level of 21 lipid species differed in eOA SF versus SF from lOA, an observation that can be used to develop biomarkers. Sphingolipids can alter synovial inflammation and the repair responses of damaged joints. Thus, our lipidomic study provides the foundation for studying the biosynthesis and function of lipid species in health and most prevalent joint diseases.
A Presuppositional Critique of Constructivism
Paul R. Rickert
Christian Perspectives in Education , 2009,
Abstract: Educational theories have roots. They have roots in broader philosophies, conceptions of the nature of reality, and the theories utilized in classrooms to teach have implications for broader society. The author takes a presuppostitional view and shows that all systems have most basic beliefs that are un-provable. So at the heart of any form of interpretive schema or paradigm is faith in that schema. The author discusses the role of theories of truth, how fact-constructivism embraces a relativist position that is self-refuting, and ultimately is untenable absent a suspension of laws of logic. The author argues in favor of revelation from God as axiomatic and demonstrates how logic can exist on that basis, whereas on a secular basis, philosophy cannot generate any True facts whatsoever. The author then looks at the educational theory of constructivism and examines the theory and practices it endorses it in light of the presuppositional critique and concludes that the relativistic nature of constructivism precludes it from being a philosophically acceptable approach for the Christian.
Experiences with a simplified microsimulation for the Dallas/Fort Worth area
M. Rickert,Kai Nagel
Physics , 1997, DOI: 10.1142/S0129183197000400
Abstract: We describe a simple framework for micro simulation of city traffic. A medium sized excerpt of Dallas was used to examine different levels of simulation fidelity of a cellular automaton method for the traffic flow simulation and a simple intersection model. We point out problems arising with the granular structure of the underlying rules of motion.
Parallel implementation of the TRANSIMS micro-simulation
Kai Nagel,Marcus Rickert
Computer Science , 2001,
Abstract: This paper describes the parallel implementation of the TRANSIMS traffic micro-simulation. The parallelization method is domain decomposition, which means that each CPU of the parallel computer is responsible for a different geographical area of the simulated region. We describe how information between domains is exchanged, and how the transportation network graph is partitioned. An adaptive scheme is used to optimize load balancing. We then demonstrate how computing speeds of our parallel micro-simulations can be systematically predicted once the scenario and the computer architecture are known. This makes it possible, for example, to decide if a certain study is feasible with a certain computing budget, and how to invest that budget. The main ingredients of the prediction are knowledge about the parallel implementation of the micro-simulation, knowledge about the characteristics of the partitioning of the transportation network graph, and knowledge about the interaction of these quantities with the computer system. In particular, we investigate the differences between switched and non-switched topologies, and the effects of 10 Mbit, 100 Mbit, and Gbit Ethernet. keywords: Traffic simulation, parallel computing, transportation planning, TRANSIMS
La biología de Pogonomyrmex cunicularius pencosensis (Hymenoptera: Formicidae) en relación con su comportamiento como dispersora de semillas coneleosoma en el Noroeste semiárido argentino The biology of Pogonomyrmex cunicularius pencosensis (Hymenoptera: Formicidae) in relationship to its behaviour as disperser of elaiosome-bearing seeds in semiarid Northwest Argentina
Adriana Aranda-Rickert,Sebastián Fracchia
Revista de la Sociedad Entomol?3gica Argentina , 2012,
Abstract: Pogonomyrmex cunicularius pencosensis Forel es la dispersora dominante de semillas con eleosoma en el Desierto del Monte septentrional del Noroeste semiárido de Argentina. En este trabajo, se estudian varios aspectos de la biología de esta especie de hormiga, relacionados con su capacidad para dispersar semillas mirmecócoras. Se presentan datos sobre la nidificación, el tama o de la colonia, la dieta y la estrategia de forrajeo de P. cunicularius pencosensis. Finalmente, se discute cómo todos estos aspectos de la historia natural de P. cunicularius pencosensis podrían influenciar positivamente sobre la dispersión de semillas mirmecócoras de plantas nativas del área de estudio, así como sus implicancias ecológicas y evolutivas. Pogonomyrmex cunicularius pencosensis Forel is the dominant disperser of elaiosome bearing seeds in the northern Monte Desert of semiarid Northwest Argentina. In this study, various aspects of the biology of this ant species were examined and related to its ability to disperse myrmecochorous seeds. Data are presented on P. cunicularius pencosensis nesting habits, colony size, feeding habits and foraging behaviour. Finally, it is discussed how all these aspects of the life history of P. cunicularius pencosensis may positively influence the seed dispersal of native myrmecochorous plants, as well as their ecological and evolutive implications.
Paradoxical hepatic tumor: Undifferentiated embryonal sarcoma of the liver
Sodhi Kushaljit,Bekhitt Elhamy,Rickert Christian
Indian Journal of Radiology and Imaging , 2010,
Abstract: Undifferentiated embryonal sarcoma (UES) is a rare primary malignant tumor of the liver that typically presents in late childhood. We report a case of primary UES, which had a typical paradoxical appearance on different imaging modalities.
Back to the Past: Marxist Concepts Reborn
Phillip A. Smith,Joseph A. Rickert
Journal of Alternative Perspectives in the Social Sciences , 2009,
Abstract: Since the end of the Cold War, theorists have proclaimed theend of Marxism and the celebrated superiority of the capitalist system. However, after nearly two decades of an international system where free market capitalism has not faced any viable competition from rival ideologies, we have seen not the unbridled success of the capitalist system, but rather its continued weakening and its transformation into an increasingly unstable and unsustainable system built on false wealth and dubious accounting practices that survives by the proliferation of consumer debt. When this enormous economic bubble bursts, the entire economy is threatened to go down with it unless it is salvaged by massive government spending plans to sustain the system. In this paper we use Marx’s principles of Estranged Labour &Alienation, Loss of Surplus & Value, and Fetishisms with Commodities and Exchange to outline thefundamental themes that are present in the international system, which have allowed for the rebirth of Marxian principles and which have been validated through the current economic/political environment of the international system.
东北太平洋天然气水合物伴生沉积物中自生石膏矿物
王家生,E.,Suess,D.,Rickert
中国科学 地球科学 中国科学 地球科学 , 2003,
Abstract: ?自生微球粒状石膏集合体和颗粒状石膏集合体被首次发现于东北太平洋水合物脊海区的两个沉积物钻孔SO143-221和SO143/TVG40-2中.X光粉晶衍射和电子探针分析表明,上述两种不同形态的集合体内矿物晶体均具有典型的石膏衍射峰和化学成分,其中主要化学组成略小于其他海区自生石膏.扫描电子显微镜分析显示,石膏呈清晰的单晶和双晶,清晰的晶体边界、晶面、晶棱和解理面.结合沉积物岩芯中已发现的与水合物伴生的自生碳酸盐岩和富含SO42-和Ca2+离子的孔隙水,有理由认为这类石膏是自生形成于与水合物相关的沉积环境中,很可能形成于研究区富含SO42-离子的海底水与下伏沉积物中甲烷水合物层之间的交互地段.自生的颗粒状石膏集合体和石膏微球粒集合体分别产自同一研究区不同的钻孔沉积物内,说明了两个钻孔位置处在不同的微地球化学动力环境.因此,这种特征性自生石膏可视作一种识别标志应用于其他海区,以确定其沉积环境是否与天然气水合物有关.
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