375 research outputs found

    Benzo-fused Tri[8]annulenes as Molecular Models of Cubic Graphite

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    Cyclotrimerization of 9,10‐dibromo‐9,10‐dihydrodibenzo[3,4:7,8]cycloocta[1,2‐l]phenanthrene with potassium tert‐butoxide in the presence of a transition‐metal catalyst afforded two polycyclic aromatic hydrocarbon stereoisomers consisting of three cyclooctatetraene (COT) moieties connected via a central benzene ring. Both isomeric tri[8]annulenes were obtained selectively through the choice of the catalyst: The α,α,α‐form (Ru catalyst) displayed a threefold symmetrywith the COT subunits forming the side walls of a (chiral) molecular cup. In the thermodynamically more stable α,α,β‐isomer (Pd catalyst), one of the three boat‐shaped COTs was flipped over and faced the opposite molecular hemisphere with respect to the central benzene ring as evidenced by crystal structure analysis. Both title compounds are small segments of “cubic graphite”, an elusive carbon allotrope

    Bio-responsive polymer hydrogels homeostatically regulate blood coagulation

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    Bio-responsive polymer architectures can empower medical therapies by engaging molecular feedback-response mechanisms resembling the homeostatic adaptation of living tissues to varying environmental constraints. Here we show that a blood coagulation-responsive hydrogel system can deliver heparin in amounts triggered by the environmental levels of thrombin, the key enzyme of the coagulation cascade, which - in turn - becomes inactivated due to released heparin. The bio-responsive hydrogel quantitatively quenches blood coagulation over several hours in the presence of pro-coagulant stimuli and during repeated incubation with fresh, non-anticoagulated blood. These features enable the introduced material to provide sustainable, autoregulated anticoagulation, addressing a key challenge of many medical therapies. Beyond that, the explored concept may facilitate the development of materials that allow the effective and controlled application of drugs and biomolecules

    Albumin-coupled methotrexate (MTX-HSA) is a new anti-arthritic drug which acts synergistically to MTX

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    Objective. To evaluate the anti-arthritic effects of the new inflammation-targeted drug MTX-HSA and to investigate whether peripheral blood mononuclear cells (PBMC) are potential target cells for albumin-mediated drug delivery. Methods. The murine model of collagen-induced arthritis (CIA) was used to measure the anti-arthritic effect of MTX, MTX-HSA or a combination of both (n = 30 to 35 per group). In addition, the uptake of fluorescence-labelled albumin (AFLc-HSA) in PBMC of 14 patients with RA was measured by fluorescence-activated cell sorting (FACS). Results. In equivalent doses of 7.5 mg/kg intravenously (IV) twice a week, MTX-HSA is significantly (P<0.02) superior to MTX in inhibiting the development of CIA and reducing the joint count as well as the number of affected paws. When given in lower doses as combination therapy, both drugs act synergistically (P<0.03). A mean of 96, 72 and 64% of the CD14-, CD16- and CD20-positive cells from peripheral blood of rheumatoid arthritis (RA) patients showed an uptake of albumin after incubation with AFLc-HSA in vitro. This finding was not significantly different in comparison to healthy controls. In contrast, the number of CD3-positive cells taking up albumin is increased significantly in RA patients in comparison to controls (26.3 ± 12.9% s.d. vs 11.6 ± 7.3% s.d.; P = 0.005). Conclusion. The data show that the effectiveness of MTX-HSA in CIA is superior to MTX and that both drugs act synergistically. In addition, albumin appears to be taken up by peripheral blood cells, suggesting that they might be one of the potential target cells of this novel anti-arthritic treatment approac

    Deoxyribonucleic Acid as a Universal Electrolyte for Bio-Friendly Light-Emitting Electrochemical Cells [in press]

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    In the search for bio and eco‐friendly light sources, light‐emitting electrochemical cells (LECs) are promising candidates for the implementation of biomaterials in their device architecture thanks to their low fabrication complexity and wide range of potential technological applications. In this work, the use of the DNA derivative DNA‐cetyltrimethylammonium (DNA‐CTMA) is introduced as the ion‐solvating component of the solid polymer electrolyte (SPE) in the active layer of solution‐processed LECs. The focus is particularly on the investigation of its electrochemical and ionic conductivity properties demonstrating its suitability for device fabrication and correlation with thin film morphology. Furthermore, upon blending with the commercially available emissive polymer Super Yellow, the structure property relationship between the microstructure and the ionic conductivity is investigated and yields an optimized LEC performance. The large electrochemical stability window of DNA‐CTMA enables a stable device performance for a variety of emitters covering the complete visible spectral range, thus highlighting the universal character of this naturally sourced SPE

    Обновленные рекомендации EULAR/ERA–EDTA 2019 г. по терапии волчаночного нефрита. Комментарии экспертов. Часть II

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    The paper presents the main provisions of the updated 2019 EULAR/ERA-EDTA guidelines for the lupus nephritis (LN) therapy, which have been prepared by an international group of rheumatologists, nephrologists, morphologists, and pediatricians. Part 2 of the article discusses additional therapy, monitoring, and prognosis for LN, and the management of patients with end-stage renal failure and antiphospholipid syndrome. Attention is paid to the problem of LN and pregnancy, as well as to the management of pediatric patients with kidney damage.Представлены основные положения обновленных рекомендаций EULAR/ERA–EDTA 2019 г. по терапии волчаночного нефрита (ВН), подготовленных международной группой ревматологов, нефрологов, морфологов и педиатров. Во второй части статьи обсуждаются дополнительная терапия, мониторинг и прогноз при ВН, вопросы ведения пациентов с терминальной почечной недостаточностью, антифосфолипидным синдромом. Уделено внимание проблеме ВН и беременности, а также тактике ведения пациентов детского возраста с поражением почек

    Head of State of Exception

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    During the escalation of the “German Autumn” in 1977 the Federal German government resorted to a specific form of crisis management that had been described as an undeclared state of exception. It was Federal chancellor Helmut Schmidt in the first place who oversaw the anti-terrorist measures in the situation room where the executive branch ruled for six weeks beyond any parliamentary control. This article examines the role that Helmut Schmidt had played for the creation of a “subjective state of exception” (Julius Hatschek) and how this could be seen as stemming from Schmidt’s earlier experiences and handling of crisis situations dating back to the 1960s. In this regard it has to be asked with Giorgio Agamben, if in the West German case, the state of exception had become the rule
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