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High Extent (high + extent)
Selected AbstractsSynthesis and biological evaluation of new benzo[f]furo[2,3- h]-and benzo[f]pyrano[2,3- h]coumarin derivatives. ,JOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 3 2007Maria Tsoukka Furocoumarins 3,5 and pyranocoumarin 7 were synthesized from the reaction of furonaphthalenediones 2,4 and pyranonaphthalenedione 6 respectively with carbethoxymethylene(triphenyl)phosphorane in refluxing DCM for 3-6 hours or under microwave irradiation in toluene for a few minutes. Compounds 3,5,7 and their precursors were tested as anti-inflammatory/antioxidant agents. They were found to compete significantly high DMSO for OH radicals, to scavenge O2, and to inhibit lipoxygenase to a high extent. [source] Microemulsions as colloidal vehicle systems for dermal drug delivery.JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2005Part V: Microemulsions without, with glycolipid as penetration enhancer Abstract The aim of this study was to investigate the dermal administration of a highly hydrophilic model drug, diphenhydramine (DPH), in colloidal systems with an aqueous colloidal phase in the presence of a glycolipid (GL) as a penetration modifier. Dermal penetration of DPH, GL, and isopropylpalmitate (IPP) from ME systems without GL and with GL as well as from a hydrogel used as standard formulation were estimated in vitro using human skin. The penetration of the drug, the oil (IPP), and the GL was measured with highly sensitive HPLC, HPLC-MS, and GC-MS assays, respectively. It could be shown that penetration modifier GL is penetrating very fast, and to a high extent into and through the human skin. In contrast, the penetration of IPP used as oily phase in the ME is limited. When incorporated in the ME systems GL and DPH was accumulated in the viable epidermis and in the dermis. Using ME containing a penetration modifier such as GL, a slight additional enhancing effect could be observed, particularly concerning the penetration of DPH into the acceptor fluid when a highly hydrophilic drug such as DPH was applied. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:821,827, 2005 [source] Modification of Polymer Substrates with Low Surface Free Energy Material by Low-Temperature Cured PolybenzoxazineMACROMOLECULAR RAPID COMMUNICATIONS, Issue 1 2008Chun-Syong Liao Abstract The B-ala/AIBN PBZ system has a high extent of ring-opening of oxazine because phenol-containing oligomers are formed at the early stage of the curing process. As a result, the B-ala/AIBN PBZ system possesses a relatively stronger intramolecular hydrogen bonding and lower surface energy than the pure B-ala system at low temperature curing. In this context, poly(4-vinyl pyridine), poly(4-vinyl phenol) thin films and polycarbonate substrates, which lack liquid resistance, possess low surface free energy after modification with B-ala/AIBN,=,5/1 PBZ. [source] A New View of the Anionic Diene Polymerization MechanismMACROMOLECULAR SYMPOSIA, Issue 1 2004A.Z. Niu Abstract We investigated the anionic polymerization of butadiene in d-heptane solvent using tert -butyl lithium as initiator. Two complementary techniques were used to follow the polymerization processes: 1H NMR and small angle neutron scattering (SANS). The time resolved 1H NMR measurements allowed us to evaluate quantitatively the kinetics of the processes involved. The initiation event commences slowly and then progressively accelerates. This indicates an autocatalytic mechanism. The microstructure of the first monomer units attached is to a high extent 1,2. The disappearance of initiator --- at about 10% monomer conversion --- signals the onset of the normal ,6% vinyl content of the chain. Small angle neutron scattering was used to study the aggregation behavior of the carbon lithium head groups. It is well known that the polar head groups aggregate and form micellar structures. For dienes in non-polar solvents the textbook mechanism assumes the formation of only tetramers during the propagation reaction. By combining 1H NMR and SANS results we were able to determine quantitatively the aggregation number during all stages of the polymerization. Our measurements show the existence of large-scale structures during the initiation period. The initial degree of aggregation of more than 100 living polymer chains diminished as the polymerization progressed. In addition, even larger, giant structures with Nagg >>1000 and Rg , 1000Å were found. [source] Q- und R-Matten aus Kunststoff für Bewehrungsaufgaben in der GeotechnikBAUTECHNIK, Issue 9 2004Georg Heerten Dr.-Ing. Wachsende Güterströme und Warenverkehre im Zentrum eines wachsenden Europas und zunehmender Warenaustausch als Folge der Globalisierung der Weltwirtschaft stellen erhebliche Anforderungen an den Erhalt und Ausbau leistungsfähiger Infrastruktursysteme (Straße, Schiene, Wasserstraße). Nachhaltigkeitskonzepte bei der Bautätigkeit und Finanzierungsprobleme der öffentlichen Auftraggeber sind aktuelle Randbedingungen, denen mit Geokunststoff-Bauweisen optimal Rechnung getragen werden kann. Es können neben den technischen auch die ökonomischen und ökologischen Vorteile , Baukosten sparen, Baustoffressourcen schonen , parallel genutzt werden. Eine Stützwand als "Bewehrte-Erde-Konstruktion" kann ganz erheblich kostengünstiger als eine Stahlbeton-Stützmauer hergestellt werden. Die Ertüchtigung von wenig tragfähigen Böden mit flächig angeordneten Bewehrungslagen und/oder pfahlartigen geokunststoffummantelten Bodensäulen vermeidet umfangreichen Bodenaustausch, spart Kosten, verhindert umfangreichen Transport von Bodenmassen mit LKWs. Hierdurch werden knappe Baustoffressourcen wie Sand und Kies geschont sowie eine z. T. erhebliche Entlastung örtlicher Verkehrswege bewirkt. Q and R mats made of synthetics for reinforcement functions in the field of geotechnics. An increasing flow of goods in a growing central Europe, resulting from the globalisation of the world economy, makes high demands on the maintenance and development of an efficient infrastructure (road, railway, waterway). Sustainability concepts for the construction activities and funding problems of the contracting authorities are current boundary conditions which can be accommodated optimally with geosynthetic construction methods. At the same time, besides the technical advantages, the economical and ecological advantages can be used too , saving of construction costs and taking care of building materials resources. A retaining wall as "Reinforced-Earth-Structure" can be constructed at much lower cost than a retaining wall made of reinforced concrete. The improvement of subsoils with low bearing capacity, by using reinforcing layers in the area and/or soil columns similar to piles wrapped with geosynthetics, avoids a considerable exchange of soil, saves costs and avoids substantial soil transports by trucks. Thus, care is taken on rare building materials resources like sand and gravel and the traffic routes are partly released to a high extent. [source] Therapeutic drug monitoring of itraconazole and the relevance of pharmacokinetic interactionsCLINICAL MICROBIOLOGY AND INFECTION, Issue 2006A. Domínguez-Gil Hurlé Abstract A review of the pharmacological aspects of greatest relevance in relation to the monitoring of itraconazole serum levels is presented in this article. The main causes of pharmacokinetic variability, e.g., poor aqueous solubility, the presystemic first-pass effect with the involvement of transporters such as P-glycoprotein, the high extent of metabolism mediated by the CYP450 system and a high probability of pharmacological interactions, are documented and discussed. The pharmacokinetic,pharmacodynamic criteria used to optimise antibiotic therapy, as well as their application to antifungal drugs, are also discussed. Data concerning the breakpoints established for the minimum serum concentrations of itraconazole are included, and the most relevant justifications for drug monitoring are cited. [source] Improving kp Data Originating from PLP Number DistributionsMACROMOLECULAR THEORY AND SIMULATIONS, Issue 3 2006Andreas Kornherr Abstract Summary: Based on certain features, especially the width of the so-called extra peaks in the simulated number-chain-length distribution (CLD) of polymers prepared by pulsed laser polymerization (PLP), it is calculated by which factor the positions of the points of inflections and maxima deviate from the theoretical L0 data that are to be used for the evaluation of kp. These corrections are for slightly chain-length-dependent termination by disproportionation or combination and cover a wide range of chain-lengths and primary radical production. They can be applied either to the point of inflection on the low-molecular weight side of the extra peaks or to the peak maximum. On average, the mean error that is about ,2.5% for uncorrected data from first-order points of inflection is reduced to the order of less than 1% even if no assumption concerning the mode of termination is made. The situation is similar for the positions of the first-order peak maxima where the mean error of about +7% likewise can be cut down to less than 1% if the proper correction function is chosen. Second- and third-order peaks data, which are a priori less falsified, yield still better results after correction. Mass sensitivity of the detection process has comparatively little effect: it is only for unrealistically high extents of chain-length dependence in detection that considerable falsifications are to be expected. As an additional result it turned out that correction functions obtained for number distributions are also applicable to mass spectrometry raw distributions and even for mass distributions x(l),·,l provided Poissonian broadening is the only broadening process. Number distribution xC(l) calculated for termination by combination times attenuation function F1(l). [source] | |||||||||||||