Careful Manipulation (careful + manipulation)

Distribution by Scientific Domains
Polymers and Materials Science40%

Selected Abstracts

Solution Synthesis of Two Orthogonally Protected Lactosides as Tetravalent Disaccharide-Based Scaffolds

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 13 2004
Sergio Castoldi
Abstract Two tetravalent lactosidic scaffolds have been synthesised in solution from commercial lactose. Careful manipulation of the protecting groups allowed us to orthogonally protect four OH groups for their use as diversity sites for the development of broad screening libraries of sugar mimics. The selective access to each of these hydroxy groups has been demonstrated on scaffold 2 by deprotection and functionalisation with p -fluorophenyl isocyanate. Finally, the 6-OH derivative of compound 2 was covalently attached to a polymeric support. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

Dynamic Magnetic Properties of Ferroic Films, Multilayers, and Patterned Elements

ADVANCED FUNCTIONAL MATERIALS, Issue 15 2010
Robert L. Stamps
Abstract Modification and control of material properties through careful manipulation of geometry on nano- and sub-nanometer length scales is a cornerstone of modern materials science and technology. An exciting area in which these concepts have provided exceptional advances has been magnetoelectronics and nanomagnetism. Important scales in magnetic metals are conduction spin diffusion lengths and distances over which local moments correlate. Advanced techniques now allow for the creation of structures patterned on these length scales in three dimensions. The focus of this article is on magnetic structures whose dynamic properties can be strongly modified by ion bombardment and lithographic patterning. Examples are given of how microwave frequency properties can be tuned with external fields, how factors controlling magnetic switching can be controlled, and how manipulation of magnetic domain walls can be used to reveal new and surprising phenomena. [source]

A double-blind randomized vehicle-controlled clinical trial investigating the effect of ZnPTO dose on the scalp vs. antidandruff efficacy and antimycotic activity

INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 4 2003
P. Bailey
Synopsis Dandruff is a common problem in approximately 30% of the world's population. Reports in the literature regarding treatment of this condition with various antidandruff shampoos usually report the level of active ingredient within the formulation. However, we propose that a more important parameter relating to antidandruff efficacy is the amount of active ingredient delivered to the scalp from the shampoo. This report describes the results from two studies designed to investigate the relationship between the level of zinc pyrithione (ZnPTO) deposited onto the scalp and the resultant scalp condition. A double-blind randomized vehicle-controlled clinical study comparing three shampoos , a vehicle, a low-depositing ZnPTO shampoo and a high-depositing ZnPTO shampoo , was carried out in the U.K. with 53 panelists with dandruff or mild-to-moderate seborrheic dermatitis of the scalp. Both shampoos containing ZnPTO were significantly superior in antidandruff efficacy to the vehicle. Furthermore, the high-depositing ZnPTO shampoo was significantly superior compared with the low-depositing ZnPTO shampoo in terms of both antidandruff efficacy and antimycotic activity. Antidandruff performance and antimycotic activity of ZnPTO-containing shampoos is highly dependent on the amount of active ingredient delivered to the scalp. Furthermore, careful manipulation of the formulation parameters of an antidandruff shampoo can result in enhanced levels of delivery of the active ingredient without having to increase the level of active ingredient within the formulation. Résumé Les pellicules sont un problème courant rencontré par environ 30% de la population mondiale. Les rapports de la littérature relatifs à son traitement par des shampooings antipelliculaires mentionnent couramment le taux d'actif inclus dans la formule. Nous proposons cependant un paramètre plus important, vis à vis de l'activité antipelliculaire, c'est à dire le taux d'actif délivré par le shampooing sur le cuir chevelu. Cet article décrit les résultats de deux études conçues pour déterminer les types de relation entre le taux de Zn PTO déposé sur le cuir chevelu et l'état de celui ci qui en résulte. Une étude randomisée, contrôlée par véhicule, a comparé 3 shampooings (la base véhicule non traitante, un shampooing à faible déposition de Zn PTO et un shampooing à fort taux de dépôt de Zn PTO), a été conduite au Royaume Uni sur 53 volontaires sujets pelliculaires ou à faible ou modérée Dermite Séborrhéique. Les deux shampooings contenant le Zn PTO ont été trouvés significativement supérieurs dans leur activité anti pelliculaire au véhicule. De plus, le shampooing à fort dépôt était significativement plus efficace que celui à faible dépôt, tant dans l'activité anti pellicualire qu'anti mycotique. En conclusion, la performance anti pelliculaire et anti mycotique de shampooings à base de Zn PTO semble hautement dépendante du taux d'actif délivré sur le cuir chevelu. De plus, un choix judicieux des paramètres de formulation du shampooing anti pelliculaire peut amener à accroître les taux de délivrance de l'actif sans avoir à augmenter celui ci au sein de la formule. [source]

New tricks of an old molecule: lifespan regulation by p53

AGING CELL, Issue 5 2006
Johannes H. Bauer
Summary As guardian of the genome the tumor suppressor p53 controls a crucial point in protection from cellular damage and response to stressors. Activation of p53 can have beneficial (DNA repair) or detrimental (apoptosis) consequences for individual cells. In either case activation of p53 is thought to safeguard the organism at large from the deleterious effects of various stresses. Recent data suggest that the function of p53 might also play a role in the regulation of organismal lifespan. Increased p53 activity leads to lifespan shortening in mice, while apparent reduction of p53 activity in flies leads to lifespan extension. Although the mechanism by which p53 regulates lifespan remains to be determined, these findings highlight the possibility that careful manipulation of p53 activity during adult life may result in beneficial effects on healthy lifespan. [source]

Processing and Properties of a Porous Oxide Matrix Composite Reinforced with Continuous Oxide Fibers

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2003
Magnus G. Holmquist
A process to manufacture porous oxide matrix/polycrystalline oxide fiber composites was developed and evaluated. The method uses infiltration of fiber cloths with an aqueous slurry of mullite/alumina powders to make prepregs. By careful manipulation of the interparticle pair potential in the slurry, a consolidated slurry with a high particle density is produced with a sufficiently low viscosity to allow efficient infiltration of the fiber tows. Vibration-assisted infiltration of stacked, cloth prepregs in combination with a simple vacuum bag technique produced composites with homogeneous microstructures. The method has the additional advantage of allowing complex shapes to be made. Subsequent infiltration of the powder mixture with an alumina precursor was made to strengthen the matrix. The porous matrix, without fibers, possessed good thermal stability and showed linear shrinkage of 0.9% on heat treatment at 1200°C. Mechanical properties were evaluated in flexural testing in a manner that precluded interlaminar shear failure before failure via the tensile stresses. It was shown that the composite produced by this method was comparable to porous oxide matrix composites manufactured by other processes using the same fibers (N610 and N720). The ratio of notch strength to unnotch strength for a crack to width ratio of 0.5 was 0.7,0.9, indicating moderate notch sensitivity. Interlaminar shear strength, which is dominated by matrix strength, changed from 7 to 12 MPa for matrix porosity ranging from 38% to 43%, respectively. The porous microstructure did not change after aging at 1200°C for 100 h. Heat treatment at 1300°C for 100 h reduced the strength for the N610 and N720 composites by 35% and 20%, respectively, and increased their brittle nature. [source]