Search

The membrane insertion of human group IB phospholipase A2 (hlBPL[A.sub.2]) is analyzed and compared with that of a structurally homologous V3W mutant of human group IIA PL[A.sub.2] (V3W-hIlAPL[A.sub.2]) and with a structurally divergent group II1 bee venom PL[A.sub.2] (bvPL[A.sub.2]). Increasing the anionic charge of membranes results in a blue shift of the fluorescence of [Trp.sup.3] of hIBPL[A.sub.2], a decrease in quenching by acrylamide, and an increase in enzyme activity, reflecting an enhancement in the membrane binding of PL[A.sub.2].

Two natural alkaloids, oncinotine and neooncinotine are synthesized with the help of efficient ring-closing metathesis (RCM) reactions. Two different methods are developed to achieve the Michael addition of acrylamide and two amidations of succinic anhydride and Grubbs catalyst are used to form the 17- and 18-membered lactams in 50% and 68% yields, respectively.

Rhodium-catalyzed asymmetric 1,6-addition of arylboronic acids to [beta]-alkynyl acrylamides substituted with a silyl group on the alkyne terminus to give high yields of axially chiral allenylsilanes is reported. Asymmetric synthesis of axially chiral allenylsilanes is performed in the presence of rhodium/chiral diene complex.

Two-dimensional microfluidic architecture is shown that has integrated polyacrylamide gel electrophoresis (PAGE) with immunoblotting in a fully automated format. A complete native immunoblot of free prostate specific antigen from human seminal fluid is shown and the analysis of post-PAGE electrophoretic transfer has displayed high efficiency and minimal sample dispersion.

Binding of highly branched poly(N-isopropylacrylamide) with vancomycin end groups to Staphylococcus aureus has induced a coil-to-globule phase transition. The polymers have aggregated the Gram-positive bacteria over a wide range of temperatures, but cooling to 24-26 [degree]C has progressed the polymer-bound bacteria through a globule-to-coil phase transition, after which the bacteria are released.

The site-directed tryptophan fluorescence (SDTF) was applied to the AB and GH loops to study the pH-driven conformational changes relevant to ligand binding. A significant difference observed in the titration curves between the holo and apo forms of the W28 mutant indicated that the conformational switches of the AB loop relevant to ligand binding was modulated by protonation states of the residues around position 28.

Poly(N-cyclopropylacrylamide) (p-PNCPA) has varied the dispersion state of single-walled carbon nanotubes (SWNTs) in water and it is a thermo-responsive polymer whose conformation has changed with temperature, leading to changes in the nanotube dispersion state. The drying of the p-PNCPA aqueous suspensions have produced composites whose microstructure and electrical conductivity have changed with drying temperature and the stimuli-controlled dispersion of carbon nanotubes have a variety of applications in nanoelectronics.

A novel approach is described for the temperature-triggered development of water-soluble photoresists based on photocleavable poly(N-isopropylacrylamide) copolymers. The photocleavable groups are deprotected resulting in an increased Lower Critical Solution Temperature (LCST) and the illuminated parts of spin-coated copolymers layers dissolve at higher temperatures than the surrounding areas, leading to pattern development.

A cationic rhodium(I)/(R,R)-QuinoxP* complex has catalyzed the highly enantioselective direct intermolecular hydroacylation of [alpha]-substituted acrylamides with unfunctionalized aliphatic aldehydes to produce the corresponding [gamma]-ketoamides in high yields.

The grafted polymer from silicon nanowire arrays via surface-initiated atom transfer radical polymerization was used to construct nanoscale topography on a thermally responsive poly(N-isopropylacrylamide) (PNIPAAm) surface. The results provide insight into the applications of PNIPAAm in the fields of biomaterials and biomedicine under human physiological temperature and as a new strategy for fabricating other blood-compatible materials.

A range of partially modified retro (PMR) [psi][NHC[H.sub.2]] peptide mimetics containing hydrolytically stable C[H.sub.2]CH(C[F.sub.3])CO unit are prepared. The conformational study of the newly prepared peptidomimetics has shown a [beta]-turn-like conformation for the structures both in the solid state and in solution.

A new form factor model is used for analyzing small-angle neutron scattering data from a thermosensitive copolymer microgel consisting of N-isopropylacrylamide (PNIPAM) and N-isopropylmethacrylamide (PNIPMAM regions). The results have shown that a one-pot synthesis has led to a highly sophisticated material with phase separated domains on a microscopic length scale.

The phase behavior of N-(isopropyl)propionamide (NiPPA), which is the repeat unit of poly(N-isopropylacrylamide) (PNiPA), in deuterated aqueous solution is examined. The differences in the spectroscopic results of polymer and repeat unit solutions are understood from the phase behavior of NiPPA and PNiPA.

The dynamic behavior of the phase separation of aqueous solutions is analyzed by a laser T-jump method. The studies have shown that the values of time constants increased linearly with increasing square of hydrodynamic radius.

The layer-by-layer assembly of polyelectrolyte multilayers on soft and porous temperature-sensitive poly(N-isopropylacrylamide) (PNiPAM) microgel is described. Fluorescence correlation spectroscopy is used for distinguishing free labeled polyelectrolytes and those bound to the microgel.

The article presents two newly devised strategies that lead to the asymmetric coordination polymerization of the acrylamides by employing the enantiomeric metallocenium enolate catalysts to achieve better optical activity. The described polymerization technique is found to be extremely useful, as it offers excellent opportunities for the production of optically active chiral polymers, mediated by various readily available chiral metallocene catalysts.

A study seeks to compare the thermoresponsive properties of the copolymers P(ME[O.sub.2]MA-co-OEGMA) to those of poly(N-isopropylacrylamide) (PNIPAM), which is considered the 'gold standard' of thermoresponsive polymers. Findings show that P(ME[O.sub.2]MA-co-OEGMA) copolymers can be considered as ideal structures, which combine both the properties of poly-(ethylene glycol) (PEG) and PNIPAM in a single macromolecule.