Flammability and Thermal Properties of Polyamide 11-Alumina Nanocomposites

Neat polyamides 11 and 12 lack high strength/high heat resistance and flame retardancy. The incorporation of selected nanoparticles is expected to enhance these properties to a level that is desired and required for performance driven applications. This enhancement may result in additional market opportunities for the polyamide 11 and 12 polymer manufacturers. The objective of this study is to develop polyamide 11 polymer nanocomposites with enhanced thermal, flammability, and mechanical performance for selective laser sintering (SLS) rapid manufacturing. Three types of nano-alumnia (X-0 needle, X-25SR, and X-0SR) with different organic treatments were melt-compounded into polyamide 11 in three different weight loadings of the nanoparticles (2.5%, 5%, and 7.5%). Injection molded specimens were fabricated for thermal, flammability, and mechanical properties characterization. Although nano-alumina was uniformly dispersed in polyamide 11 and better thermal stability of the nanomodified materials was observed, the desired FR characteristics of the nanomodified polyamide 11 was not achieved. None of the materials passed the desired UL 94 V0 rating.Mechanical Engineerin

Zusammensetzung und chromatographisches Verhalten von dialysablen Wirkstoffen eines humanen Leukozytenultrafiltrates -HLU-

Solche zum Teil widersprüchlichen Eigenschaften hinsichtlich des chromatographischen Verhaltens polydisperser Systeme an verschiedenen Phasen einerseits, der Kohlenhydrat-, Aminosäure- und Nukleosidbasengehalte andererseits, lassen sich nach gegenwärtigem Kenntnisstand dahingehend interpretieren, daß das HLU-Präparat hauptsächlich aus verschiedenen RNP- und Oligonukleotidkomponenten besteht, die durch eine sehr komplexe Struktur geprägt sind und sehr ungewöhnliche hydrodynamische Eigenschaften haben. In dieser Hinsicht ist das HLU- Präparat im Vergleich zu herkömmlichen Präparaten eine Besonderheit. RNP-Strukturen haben in neuerer Zeit große Aufmerksamkeit auf sich gezogen durch ihre Struktur-Funktionsbezeichnungen, z. B. als Enzyme (Ribozyme), als Zytokine (Ribokine) und als Teil der Mechanismen für die Abwicklung der Pre- Messenger-RNS (1, 4, 6 - 8, 12, 14, 17, 19, 23 - 27). Weitere Untersuchungen werden zeigen, in welcher Beziehung die Bioaktivitäten des HLU-Präparates zu denjenigen der Zytokine und insbesondere der Ribokine (23 - 27) stehen

Morphogenesis and tropism of organoid vascular pattern in tissue and on interfaces in vitro.

Vascular morphogenesis, the formation of organoid capillary patterns may result from the interaction of monocytes (macrophages) and endothelial cells. Monocytic morphogen activities for endothelial cells were purified (>100'000 fold) to homogeneity and characterized in structure and function from supernatants of serum-free cultures of isolated, lectin-activated porcine peripheral monocytes and from ischemic/infarcted (inflamed) heart muscle sites prepared by transient coronary occlusion by transfemoral catheterization. An isolated monokine (angiotropin) acts as morphogen in vivo and in vitro in the femto mol range: In tissues of different species, bioactive vascular patterns are induced by sprouting and capillarization phases with vascular leaky tips in transition; a relevance of the reactions in pathophysiological phenomena is suggested and may be exemplified by transient neo-hypervascularization of skeletal muscle (rabbit) with reversible, long-lasting increase in hemodynamics as vis ualized by high 99 Tc-angioscintigrams; as corollary, on defined surfaces, in cultures of cloned endothelial cells, it induces selectively cellular differentiation, migration and spatial organization basic to in-vitro-angiogenesis (1-4). As possible differentiation makers in phenotype changes of endothelial cells, the enzymes D-xylose: NADP 1-oxidoreductase (E.C. 1.1.1.179), polyol: NADP oxidoreductases (aldose reductases, E.C. 1.1.1.21), aldehyde: NAD oxidoreductases (E.C. 1.1.1.3), aldose 1-epimerase (E.C. 5.1.3.3) and carbonate hydro-lyase (carbonic anhydrase, E.C. 4.2.1.1) were investigated (5). The morphogen structure as bioactive copper-ribonucleo-polypeptide complex (Cu-RNP) was determined by its chemical and enzymatic disintegration and modification by HPLC and micro-detection methods (1). Proteolysis of polypeptide and removal of complexing Cu-ion components resulted a RNA (75 bases) (6,7). The RNA was isolated and subjected to chemical sequence analysis. It was found peculia

Suprastrukturiertes Chitin/Chitosan, Derivate und Konfektionen davon fuer die umweltvertraegliche Materialtechnik, Hochleistungsverbundwerkstoffe und bionische Werkstoffe

Suprastructured chitin/chitosan (I) and its derivatives has: (i) a chitin/chitosan content of 0.01-99.9%, (ii) a glycan content of 0-60% and (iii) a melanin content of 0-40%. Also claimed is a process for producing the above material, comprising isolating chitin or a chitin derivative from plants or animals, treating it with a series of water-miscible organic solvents in order of decreasing boiling point, and drying the product. USE - (I) is used in compositions that may also contain polyphosphates, bio-catalysts, nucleic acids, proteins, cells, drugs and/or organic substances; in composite materials together with biogenic, abiogenic and/or synthetic materials, where the biogenic materials are preferably selected from cellulose, paper, silk, wool, fur and carbon, the abiogenic materials are preferably selected from glass, basalt, metals, magnetisable materials, magnetic materials, electric conductors and ''electrisable'' materials, and the synthetic materials are preferably selected fr om nylon, Perlon and polyurethanes, especially where the composite materials are in the form of wallpaper, floor coverings, clothing, bedding, upholstery or automobile or aeroplane parts; in biochips; in electronic chips; in information systems; in absorbents; for filtration and purification of liquids and gases; for coating interfaces and/or surfaces, especially of plastics; for production of hexosamines and pentosamines, especially D-glucosamine and acetyl-D-glucosamine

Enzymatische Halogenierung und Dehalogenierung 2 Abschlussbericht

Das grundsaetzliche Ziel des Projektes ist es, neueste Erkenntnisse ueber halogenierende und dehalogenierende Enzyme zur Loesung spezifischer Synthese-und Abbauprobleme zu verwenden. Im vorangegangenen Projektteil stand die grundlagenorientierte Suche nach entsprechenden Biokatalysatoren im Vordergrund. Die dabei gesammelten Erfahrungen wurden in diesem Folgeprojekt auf praxisnahe Probleme angewandt. Bei den halogenierenden Enzymen wurden die klonierten Nicht-Haem-Haloperoxidasen hinsichtlich Reaktionsmechanismus und technischer Verwendbarkeit genauer charakterisiert. Bei den Dehalogenasen wurde gezielt nach Aktivitaeten zur Umwandlung der in technischen Prozessen anfallenden chlorierten C3-Kohlenwasserstoffe in verwertbare Substanzen gesucht. Um diese Ziele effektiv zu erreichen, wurde die im vorausgehenden Projektteil entwickelte Halogenid-Messtechnik fuer diese speziellen Anforderungen modifiziert. Mit dieser Halogenid-Messtechnik ist ein effizientes Screening nach CKW-abbauenden Mikroorganismen aus Anreicherungskulturen moeglichThe aim of the project is to find and utilize new microorganisms and enzymes for specific synthesis problems. In the previous part the search for these activities was the main topic. Here we investigate how these activities can be utilized. With halogenating enzymes, bacterial non-heme haloperoxidases were cloned and characterized in respect to reaction mechanism, and applicability in bioreactors. With dehalogenases new organisms and enzymes for degradation of halogenated propane derivatives, which are proplematic by-products from C-3 production processes, were characterized. To achieve these goals a halide sensor technique for sensitive halide detection has been developed and adapted to measurement of halogenation and dehalogenation reactions. With this technique an efficient screening method for dehalogenating enrichment cultures and enzymatic activities has become availableSIGLEAvailable from TIB Hannover: D.Dt.F. QN1(6,32) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Entzuendungsmediatoren: chemische Anlockung, Motilitaetsbeeinflussung und molekulare Mechanismen biologischer Nachrichtenuebertragung bei der Ansammlung von Leukozyten

SIGLETechnische Informationsbibliothek Hannover: DM 5479. / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman