333 research outputs found
Die Geschichte der Lebens(un)wert-Diskussion - Bruch oder Kontinuität?
No full textSchmuhl H-W. Die Geschichte der Lebens(un)wert-Diskussion - Bruch oder Kontinuität? In: Daub U, Wunder M, eds. Des Lebens Wert – Zur Diskussion über Euthanasie und Menschenwürde. Freiburg; 1994: 51-60
Evidence for a "Wattle and Daub" Model of the Cyst Wall of Entamoeba
No full textThe cyst wall of Entamoeba invadens (Ei), a model for the human pathogen Entamoeba histolytica, is composed of fibrils of chitin and three chitin-binding lectins called Jacob, Jessie3, and chitinase. Here we show chitin, which was detected with wheat germ agglutinin, is made in secretory vesicles prior to its deposition on the surface of encysting Ei. Jacob lectins, which have tandemly arrayed chitin-binding domains (CBDs), and chitinase, which has an N-terminal CBD, were each made early during encystation. These results are consistent with their hypothesized roles in cross-linking chitin fibrils (Jacob lectins) and remodeling the cyst wall (chitinase). Jessie3 lectins likely form the mortar or daub of the cyst wall, because 1) Jessie lectins were made late during encystation; 2) the addition to Jessie lectins to the cyst wall correlated with a marked decrease in the permeability of cysts to nucleic acid stains (DAPI) and actin-binding heptapeptide (phalloidin); and 3) recombinant Jessie lectins, expressed as a maltose-binding proteins in the periplasm of Escherichia coli, caused transformed bacteria to agglutinate in suspension and form a hard pellet that did not dissociate after centrifugation. Jessie3 appeared as linear forms and rosettes by negative staining of secreted recombinant proteins. These findings provide evidence for a "wattle and daub" model of the Entamoeba cyst wall, where the wattle or sticks (chitin fibrils likely cross-linked by Jacob lectins) is constructed prior to the addition of the mortar or daub (Jessie3 lectins). Author SummaryParasitic protists, which are spread by the fecal-oral route, have cyst walls that resist environmental insults (e.g. desiccation, stomach acids, bile, etc.). Entamoeba histolytica, the cause of amebic dysentery and liver abscess, is the only protist characterized to date that has chitin in its cyst wall. We have previously characterized Entamoeba chitin synthases, chitinases, and multivalent chitin-binding lectins called Jacob. Here we present evidence that the Entamoeba Jessie3 lectin contributes to the mortar or daub, which makes the cyst wall impenetrable to small molecules. First, the Jessie3 lectin was made after chitin and Jacob lectins had already been deposited onto the surface of encysting Entamoeba. Second, cysts became impenetrable to small molecules at the same time that Jessie3 was deposited into the wall. Third, recombinant Jessie3 lectins self-aggregated and caused transfected bacteria to agglutinate. These results suggest a "wattle and daub" model of the Ei cyst wall, where the wattle or sticks (chitin fibrils likely cross-linked by Jacob lectins) is constructed prior to the addition of the mortar or daub (Jessie3 lectins).National Institutes of Health (AI44070, GM31318); Council for Scientific and Industrial Research, Government of Indi
Neutron scattering and thermodynamic studies of quantum magnetism on the kagomé lattice
No full textThesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2014.Cataloged from PDF version of thesis.Includes bibliographical references (pages 191-198).The geometry of the kagome lattice leads to exciting novel magnetic behavior in both ferromagnetic and antiferromagnetic systems. The collective spin dynamics were investigated in a variety of magnetic materials featuring spin-1/2 and spin-1 moments on kagome lattices using neutron scattering and thermodynamic probes. Both ferromagnetic and antiferromagnetic systems were studied. Cu(1,3-bdc) is an organometallic material, where the Cu2+ ions form a ferromagnetic S = 1/2. kagomé system. Synthesis techniques were developed to produce -mg-sized deuterated single crystals, and ~2,000 crystals were partially coaligned to create a sample for neutron scattering measurements. Elastic neutron scattering measurements show the existence of long range magnetic ordering below T = 1.77 K. Integrated Bragg peak intensities were analyzed to determine the structure of ordered magnetic moments. Inelastic neutron scattering measurements show the magnon dispersion spectrum, which consists of a flat high energy band and two dispersive, lower energy bands. The application of a magnetic field perpendicular to the kagome plane opens gaps between these three bands and distorts the flatness of the highest energy band. The system was modelled as a nearest-neighbor Heisenberg ferromagnet with Dzyaloshinskii-Moriya(DM) interaction. The model dispersion and scattering structure factor were calculated and fit to the data to precisely determine the strengths of the nearest-neighbor coupling and DM interaction. The observed manon band structure is a bosonic analog to the band structure of the topological insulator systems. Antiferromagnetic kagome systems can exhibit novel magnetic ground states such as quantum spin liquids and spin nematics. Thermodynamic measurements were performed on the antiferromagnetic kagome materials MgxCu₄-x(OH)₆ Cl₂ , featuring S = 1/2 moments. These measurements reveal magnetic ordering at low values of x that is suppressed with increasing x. At x = 0.75, this ordering is not fully suppressed, but susceptibility and specific heat measurements reveal behavior similar to that of the quantum spin liquid candidate herbertsmithite. Thermodynamic and neutron scattering measurements were performed on the kagome lattice material BaNi₃(OH)₂(VO₄)₂, which features S = 1 moments. These measurements reveal competing interactions, which result in a spin glass ordering transition.by Robin Michael Daub Chisnell.Ph. D
Equol but not Genistein Improves Early Metaphyseal Fracture Healing in Osteoporotic Rats
No full textHealing of predominantly metaphyseal fractures in postmenopausal osteoporosis is delayed and comparatively poor. Hormone replacement therapy could improve fracture healing, but, because of its potential side effects, natural alternatives are more appealing. The aim of this study was to determine if the soy metabolite equol and the native isoflavone genistein, in comparison to 17 beta-estradiol, improve metaphyseal fracture healing in ovariectomy-induced osteoporotic bone of the rat. Forty-eight 12-week-old female rats developed severe osteoporosis ten weeks after ovariectomy. After metaphyseal tibial osteotomy and standardized stable internal fixation, changes in callus morphology were evaluated biomechanically, qualitatively and quantitatively in fluorochrome-labeled histological sections and microradiographs in ovariectomized rats (C) and under standardized 17 beta-estradiol (E), equol (EQ) and genistein (G) supplemented rats over a period of five weeks. Estrogen and equol were able to improve the elasticity of callus formation significantly in postmenopausal osteoporotic bone (stiffness of C: 121.40 +/- 47.08 N/mm, E: 147.90 +/- 39.38 N/mm, EQ: 167.8 +/- 59.90 N/mm). The effects of estrogen were more anabolic than those of equol and were visible in changes to the trabecular bone (N.Nd of E: 6.47 +/- 7.68, EQ: 4.25 +/- 3.96). However, in terms of the whole body, equol seemed to induce less of an adverse reaction than estrogen (body weight of C: 342.20 +/- 19.91 g, E: 280.25 +/- 12.05 g, EQ: 308.75 +/- 24.28 g). Genistein as an osteoclast inhibitor influenced callus stiffness (G: 144.50 +/- 61.52 N/mm) and negatively impacted trabecular structure (N.Nd of G: 0.59 +/- 1.01) in severely osteoporotic bones. Estrogen and equol were able to improve fracture healing in ovariectomy-induced osteoporotic bones, and the extent of callus formation played only a minor role. Genistein rather negatively influenced fracture healing. The metaphyseal osteotomy model in ovariectomized rats allows an accurate study of the therapeutic effects of antiosteoporotic substances on the fracture healing process.DFG [STU 478/2-1
Raloxifene supports early fracture healing more than estrogen in ovariectomized rats
No full textObjectives: Most people suffering from osteoporosis are undiagnosed: the first osteopenic fracture strikes an untreated organism. Therefore implant fixation often fails and bone healing is disturbed. In this basic research project, we explore possibilities to improve the quality of the osteopenic bone immediately after a fracture to avoid these complications. Methods: Thirty-six female rats, which developed osteopenia within ten weeks duration after ovariectomy (OVX), underwent a standardized metaphyseal osteotomy with a bridging T-plate-fixation. After that rats were divided into three groups, which received soyfree food supplemented with raloxifene (R: 2.02 mg/d) or estradiol-17 beta-benzoate (E: 0.09 mg/d), orally, or soyfree food (SF) only. During fracture healing the rats were subcutaneously injected with fluorescent agents to help label and visualize the process of bone formation. Bones were analyzed using a three-point bending test, histological sections and microradiographs. Results: Raloxifene and estradiol have exerted anabolic effects on the trabecular bone. Both substances induced fracture healing mainly via endosteal callus formation (R: 2.08 +/- 0.66 mm(2), E: 2.02 +/- 0.75 mm(2) vs. SF: 1.78 +/- 0.74 mm(2)). Due to early bridging and advanced fracture healing, less bone occurred in the later stages after application of test substances. The biomechanical features of the callus formations determined by the Yield load of R- (100.3 +/- 28.4 N) were at the level of E-treated bone (93.8 +/- 29.7 N) being higher in both comparing to the osteopenic bones (SF: 76.4 +/- 18.8 N). Conclusions: Raloxifene and estrogen had supporting effects in the therapy of fractures of osteopenic bone. They improved not only the bone, but also the callus structure. The raloxifene- and estradiol-treatment enhanced the mechanical properties of the osteopenic bone, which probably lead to (micro) fracture risk reduction. Taking into account all the results there is an advantage for raloxifene; additionally its negative side effects detected in human settings, with respect to e.g. breast cancer propagation, are less than that of estrogens.DFG [STU 478/2-1
Raloxifene supports early fracture healing more than estrogen in ovariectomized rats
No full textObjectives: Most people suffering from osteoporosis are undiagnosed: the first osteopenic fracture strikes an untreated organism. Therefore implant fixation often fails and bone healing is disturbed. In this basic research project, we explore possibilities to improve the quality of the osteopenic bone immediately after a fracture to avoid these complications. Methods: Thirty-six female rats, which developed osteopenia within ten weeks duration after ovariectomy (OVX), underwent a standardized metaphyseal osteotomy with a bridging T-plate-fixation. After that rats were divided into three groups, which received soyfree food supplemented with raloxifene (R: 2.02 mg/d) or estradiol-17 beta-benzoate (E: 0.09 mg/d), orally, or soyfree food (SF) only. During fracture healing the rats were subcutaneously injected with fluorescent agents to help label and visualize the process of bone formation. Bones were analyzed using a three-point bending test, histological sections and microradiographs. Results: Raloxifene and estradiol have exerted anabolic effects on the trabecular bone. Both substances induced fracture healing mainly via endosteal callus formation (R: 2.08 +/- 0.66 mm(2), E: 2.02 +/- 0.75 mm(2) vs. SF: 1.78 +/- 0.74 mm(2)). Due to early bridging and advanced fracture healing, less bone occurred in the later stages after application of test substances. The biomechanical features of the callus formations determined by the Yield load of R- (100.3 +/- 28.4 N) were at the level of E-treated bone (93.8 +/- 29.7 N) being higher in both comparing to the osteopenic bones (SF: 76.4 +/- 18.8 N). Conclusions: Raloxifene and estrogen had supporting effects in the therapy of fractures of osteopenic bone. They improved not only the bone, but also the callus structure. The raloxifene- and estradiol-treatment enhanced the mechanical properties of the osteopenic bone, which probably lead to (micro) fracture risk reduction. Taking into account all the results there is an advantage for raloxifene; additionally its negative side effects detected in human settings, with respect to e.g. breast cancer propagation, are less than that of estrogens.DFG [STU 478/2-1
Química del mortero de cal del siglo XIX en una tabique Pampango (Wattle-and-Daub) de Filipinas
No full texthe chemical characterization of a thick lime mortar coating on a wall construction method in the Philippines called tabique Pampango, or wattle-and-daub method, is reported in this study. The daub material from a 19th century Spanish Colonial Period church convent in Loboc, Bohol, was analyzed using X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and sieve analysis. These analyses demonstrate that the daub material comprises a largely calcitic binder with clay minerals naturally present in the raw material or clayey soils added intentionally. The presence of clay minerals made the binder hydraulic or hardened through added water. Fine-sized aggregates are abundant in the daub material, making it suitable for non-load bearing applications. This study provided a chemical basis on the construction techniques employed during the colonial period in the Philippines that is useful for advancing conservation work and local historical knowledge.Neste estudo é relatada a caracterização química de um revestimento de argamassa de cal espessa num método de construção de paredes nas Filipinas, denominado tabique Pampango, ou método wattle-and-daub. O material de argamassa de um convento da igreja do período colonial Espanhol do século XIX em Loboc, Bohol, foi analisado mediante Fluorescência de raios X (XRF), Difração de raios X (XRD), Espectroscopia de infravermelho com transformada de Fourier (FTIR), análise termogravimétrica (TGA) e análise de peneira. Estas análises demonstram que o material é composto por um aglutinante amplamente calcítico com minerais argilosos presentes de forma natural na na matéria-prima ou solos argilosos adicionados intencionalmente. A presença de minerais argilosos tornou o aglutinante hidráulico ou endurecido por meio da adição de água. Os agregados de tamanho fino são abundantes, tornando-o adequado para aplicações que não suportam carga. Este estudo proporcionou uma base química sobre as técnicas de construção empregues durante o período colonial nas Filipinas, que é útil para o avanço do trabalho de conservação e para o conhecimento histórico local.En este estudio se informa sobre la caracterización química de un revestimiento de mortero de cal espeso en un método de construccíon de muros en Filipinas llmado tabique Pampango, o método de acacia y barro. El material de embadurnamiento de un convento de la iglesia del período colonial Español del siglo XIX en Loboc, Bohol, se analizó mediante flourescencia de rayos X (XRF), difracción de rayos X (XRD), espectroscopía infrarroja por transformada de Fourier (FTIR), análisis termogravimétrico (TGA) y analisis granulometrico. Estos análisis demuestran que el material de embadurnamiento comprende un aglutinante principalmente calcítico con minerales arcillosos presentes de forma natural en la materia prima o suelos arcillosos añadidos intencionalmente. La presencia de minerales arcillosos hizo que el aglutinante fuera hidráulico o se endureciera mediante la adición de agua. Los agregados de tamaño fino abundan en el material de embadurnamiento, lo que lo hace adecuado para aplicaciones que no soportan carga. Este estudio proporcionó una base química sobre las técnicas de construcción empleadas durante el período colonial en Filipinas que es útil para promover el trabajo de conservación y el conocimiento histórico local
Author Correction: Considerations in the search for epistasis
No full textFollowing publication of the original article [1], the authors identified that two author affiliations were incorrect. Joséphine Daub is affiliated with Utrecht University (21) and not affiliation 9. Sanne Abeln is affiliated with Utrecht University only (21) and not affiliation 1. The original article [1] has been corrected.</p
Effect of human parathyroid hormone hPTH (1–34) applied at different regimes on fracture healing and muscle in ovariectomized and healthy rats
No full textThree experiments were conducted to investigate the effect of intermittent administration of parathyroid hormone (PTH) (1-34) applied at different regimes on fracture healing and muscle in healthy and ovariectomized (Ovx at 3 months of age) rats. Five-month old rats underwent bilateral transverse metaphyseal osteotomy of tibia and were divided into groups (12 rats each). In Exp 1, Ovx rats were either treated with PTH (7x/w, 1-35d), with oral estradiol-17 beta-benzoate (0.4 mg/kg BW, 1-35d) or untreated. In Exp. 2, there were 3 groups: healthy untreated or treated with PTH (5x/w, 1-35d or 7-35d). In Exp. 3, there were 7 groups: healthy, Ovx, "healthy PTH 5x/w 7-35d", "Ovx PTH 5x/w 7-35d, 14-35d or 14-28d", "Ovx PTH every other day 7-35d". Single dosage of PTH was 40 mu g/kg BW. After 35 days of healing one tibia was analyzed by computed tomographical, biomechanical, histological analyses. The other tibia was used in analyses of Alp, Oc, Trap 1, Igf-1, Rank1, Opg genes (Exp.2, 3). Serum Oc and Alp were measured. Body, uterus weight was recorded. M. gastrocnemius was analyzed for weight (Exp. 2), fiber size and mitochondria] respiratory activity (MRA) (Exp.3). Estrogen enhanced uterus weight, prevented body increase, however, did not improve bone healing in Ovx rats (Exp. 1). PTH administration from days 1 and 7 improved bone parameters in all rats regardless of the application frequency (7, 5x/w or every other day) (Exp. 1, stiffness Ovx: 118 + 13 N/mm, Ovx PTH: 250+/-20 N/mm) being more effective in healthy rats (Exp. 3, stiffness improvement Healthy: 59 to 174 N/mm, Ovx: 52 to 98 N/mm). Serum Oc level was elevated in PTH treated rats. Application from day 14 proved to be less effective (Exp. 3). PTH had no effect (P>0.05) on body, uterus and muscle weight, muscle fiber size, MRA and expression of bone markers. PTH promoted bone healing in Ovx and healthy rats, when it is applied during early stage of healing without having any adverse systemic effect. In perspective, PTH may represent a treatment for enhancement of fracture healing. The findings need to be confirmed by follow-up studies on other animals. (C) 2010 Elsevier Inc. All rights reserved.DFG [STU 478/3-1
Antworten auf zentrale Fragen zur Einführung von CO2 Preisen
No full textDiese Zusammenstellung einiger in der Öffentlichkeit häufig diskutierter Fragen zur CO2-Bepreisung bereitet den Stand der Forschung für Interessierte auf.LEUREZitierung: Mattauch, Linus, Felix Creutzig, Nils aus dem Moore, Max Franks, Franziska Funke, Michael Jakob, Lutz Sager, Moritz Schwarz, Achim Voß, Marie-Luise Beck, Claus-Heinrich Daub, Moritz Drupp, Felix Ekardt, Gregor Hagedorn, Mathias Kirchner, Tobias Kruse, Thomas Loew, Karsten Neuhoff, Isabella Neuweg, Sonja Peterson, Matthias Roesti, Gerhard Schneider, Robert Schmidt, Reimund Schwarze, Jan Siegmeier, Philippe Thalmann, Johannes Wallacher (2019). Antworten auf zentrale Fragen zur Einführung von CO_2-Preisen. Gestaltungsoptionen und ihre Auswirkungen für den schnellen Übergang in die klimafreundliche Gesellschaft. Diskussionsbeiträge der Scientists for Future 2, 2019, doi:10.5281/zenodo.337115
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