53 research outputs found
The Role of the United Nations in a Unipolar World
Presents comments on issues concerning the role of the United Nations in a unipolar world system. Discussion on the issue concerning the failure of the Security Council to reach unanimity on the occupation of Iraq and the regime change; Views on preventive war; Information on several problems encountered by the UN wherein their actions are considered irrelevant. From the EPIIC Symposium at Tufts University, February 2004
Application of a Novel Venous Cannula for En-Bloc Removal of Undesirable Intravascular Material
Application of the focused beam reflectance measurement method (FBRM) to the characterization of plant cells in suspension culture
The ability to determine biomass levels and organism morphological characteristics is
of importance in many bioprocesses
The History, Development, and Purpose of the Sensory Integration Global Network
The Sensory Integration Global Network (SIGN) is a Web-based resource developed by a loosely structured group of international volunteers dedicated to protecting the integrity and promoting the work of Ayres Sensory IntegrationÂŽ (ASI). SIGN provides an international resource to educate the public and professionals about A. Jean Ayres and sensory integration theory and practice to help them to discriminate between ASI and other interventions, especially those that use similar descriptors of improving sensory integration and sensory processing.
This article aims to increase awareness of the existence of SIGN within the readership of the American Occupational Therapy Association\u27s (AOTA\u27 s) Sensory Integration Special Interest Section. The persons working with SIGN hope that by informing the public about the trademark and exposing both the public and professionals to the underlying principles incorporated within the trademarked ASI approach, consumers will be able to make educated choices about the types of interventions they access. Additionally, the network hopes to assist practitioners by clarifying the terminology used when describing sensory integration practice
Exploiting the continuous in situ generation of mesyl azide for use in a telescoped process
The hazardous diazo transfer reagent mesyl azide has been safely generated and used in situ for continuous diazo transfer as part of an integrated synthetic process with an embedded safety quench. Diazo transfer to βâketo esters and a βâketosulfone was successful. Inâline phase separation, by means of a continuous liquidâliquid separator enabled direct telescoping with a thermal Wolff rearrangement.
1
Predicting new molecular targets for known drugs
Although drugs are intended to be selective, at least some bind to several physiological targets, explaining side effects and efficacy. Because many drugâtarget combinations exist, it would be useful to explore possible interactions computationally. Here we compared 3,665 US Food and Drug Administration (FDA)-approved and investigational drugs against hundreds of targets, defining each target by its ligands. Chemical similarities between drugs and ligand sets predicted thousands of unanticipated associations. Thirty were tested experimentally, including the antagonism of the β1 receptor by the transporter inhibitor Prozac, the inhibition of the 5-hydroxytryptamine (5-HT) transporter by the ion channel drug Vadilex, and antagonism of the histamine H4 receptor by the enzyme inhibitor Rescriptor. Overall, 23 new drugâtarget associations were confirmed, five of which were potent (less than 100ânM). The physiological relevance of one, the drug N,N-dimethyltryptamine (DMT) on serotonergic receptors, was confirmed in a knockout mouse. The chemical similarity approach is systematic and comprehensive, and may suggest side-effects and new indications for many drugs
Biofilm Development in a Membrane Aerated Biofilm Reactor: Effect of Flow Velocity on Performance
The effect of liquid flow velocity on biofilm development in a membrane-aerated biofilm reactor was investigated both by mathematical modeling and by experiment, using Vibrio natriegens as a test organism and acetate as carbon substrate. It was shown that velocity influenced mass transfer in the diffusion boundary layer, the biomass detachment rate from the biofilm, and the maximum biofilm thickness attained. Values of the overall mass transfer coefficient of a tracer through the diffusion boundary layer, the biofilm, and the membrane were shown to be identical during different experiments at the maximum biofilm thickness. Comparison of the results with published values of this parameter in membrane attached biofilms showed a similar trend. Therefore, it was postulated that this result might indicate the mechanism that determines the maximum biofilm thickness in membrane attached biofilms. In a series of experiments, where conditions were set so that the active layer of the membrane attached biofilm was located close to the membrane biofilm interface, it was shown that the most critical effect on process performance was the effect of velocity on biofilm structure. Biofilm thickness and effective diffusivity influenced reaction and diffusion in a complex manner such that the yield of biomass on acetate was highly variable. Consideration of endogenous respiration in the mathematical model was validated by direct experimental measurements of yield coefficients. Good agreement between experimental measurements of acetate and oxygen uptake rates and their prediction by the mathematical model was achieved.Kerr-McGee Oil (U.K.) plc
Focussed beam reflectance measurement (FBRM) monitoring of particle size and morphology in suspension cultures of Morinda citrifolia and Centaurea calcitrapa
Laser light scattering technology, as applied in the Lasentec focussed beam reflectance measurement (FBRM) system, was used to characterise two morphologically dissimilar plant cell suspension cultures, Morinda citrifolia and Centaurea calcitrapa. Shake-flask suspensions were analysed in terms of biomass concentration and aggregate size/shape over the course of typical batch growth cycles. For the heavily aggregated C. calcitrapa, biomass levels [from 10-160 g fresh weight (fw) l-1)] were linearly correlated with FBRM counts. For M. citrifolia, which grows in unbranched chains of 2-10 elongated cells, linear correlation of biomass concentration with FBRM counts was applicable in the range 0-100 g fw l-1; at higher levels (100-300 g fw l-1), biomass was non-linearly correlated with FBRM counts and length-weighted average FBRM chord length. For both cell systems, particle morphology (size/shape) was quantified using semi-automated digital image analysis. The average aggregate equivalent diameter (C. calcitrapa) and average chain length (M. citrifolia), determined using image analysis, closely tracked the FBRM average chord length. The data clearly demonstrate the potential for applying the FBRM technique for rapid characterisation of plant cell suspension cultures
Dissolution Kinetics of a BCS Class II Active Pharmaceutical Ingredient
This paper presents a laboratory
study examining the dissolution
kinetics of ibuprofen crystals in water containing a phosphate buffer
(pH 7.20) at 37 °C, examining the influences of initial undersaturation
ratio, agitation rate, crystal habit, and particle size. For each
experiment, the concentration during the dissolution process was followed
using UV spectroscopy, ATR-FTIR, and FBRM methods. The dissolution
profiles were correlated using eight mathematical models, and the
dissolution rate parameters were determined. The Weibull model, the
KorsmeyerâPeppas model, and the first-order kinetics model
gave better correlation results than the other models used in this
paper for the dissolution of ibuprofen crystals. The particle size
distribution slightly shifted to the right after dissolution, confirming
that smaller particles with higher surface areas dissolved more rapidly.
During dissolution, two distinct behaviors were obtained at different
levels of undersaturation ratio; therefore, it is postulated that
the mechanism of dissolution switches from being mass-transfer-limited
at higher levels of undersaturation ratio to being limited by the
rate of surface detachment at lower undersaturation ratio levels
- âŚ