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Microscopy Experiments (microscopy + experiment)

Distribution by Scientific Domains

Chemistry	50%
Polymers and Materials Science	33%

Selected Abstracts

Formation of a new F.C.C. ,2 phase in rapidly quenched Al55Cu35V10 alloy

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2003
D. K. Misra
Abstract X-ray diffraction and transmission electron microscopy experiments were carried out to study the structure of rapidly solidified as-cast and annealed Al55Cu35V10 alloy. The as-cast Al55Cu35V10 alloy shows the presence of a new f.c.c. ,2 phase (a=0.58nm) along with a b.c.c. (a = 0.89 nm) phase which after subsequent annealing transforms into single f.c.c. phase (a = 0.58 nm). In this paper, it is also reported that these phases are crystalline approximants to an icosahedral phase on the basis of e/a (valence electron per atom) constant line. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Influence of Binding-Site Density in Wet Bioadhesion

ADVANCED MATERIALS, Issue 20 2008
Jijun Wang
The biomimetic adhesion polymer poly[(dopamine acrylamide)- co -(butylamine acrylamide)] shows strong adhesion even in aqueous environments. With single-molecule atomic force microscopy experiments, we show that the adhesion force does not depend on the density of the functional dopamine groups. [source]

Freeze-dry microscopy of protein/sugar mixtures: Drying behavior, interpretation of collapse temperatures and a comparison to corresponding glass transition Data

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2009
Eva Meister
Abstract The purpose of this study is to investigate the change in collapse appearance and temperature of protein/sugar mixtures as a function of nucleation temperature (Tn), sublimation velocity (Vsub) and the sugar/protein mole ratio when performing freeze-dry microscopy experiments. BSA and HSA were used as sample proteins and mixed with either sucrose or trehalose. Differential scanning calorimetry was used to determine the corresponding glass transition temperatures . To allow a more representative comparison between these analytical methods, a collapse midpoint temperature (Tc-50) was introduced. While there was no distinct correlation between Tn and the onset of collapse (Toc) for either mixture, Vsub was found to correlate with the measured collapse temperature which is important for comparability of experiments. Furthermore, Vsub could be used to qualitatively investigate the product resistance to water vapor flow. A dramatic change in the appearance of collapse was found for high sugar/protein mole ratios (,362:1) which needs to be considered to avoid a misinterpretation of Toc data. At low protein concentrations midpoint data showed good agreement with Toc values but were found significantly lower at higher protein concentrations. Application of the Gordon,Taylor equation failed to predict the critical temperature for any of the protein/sugar mixtures studied. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:3072,3087, 2009 [source]

Copper-mediated radical polymerization on a microcellular monolith surface

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2004
Laurence Moine
Abstract High-capacity microcellular monoliths were prepared by a two-step process, including the synthesis of a bromoester-functionalized scaffold by the copolymerization of a highly concentrated emulsion and an in situ surface polymerization of methyl methacrylate with atom transfer radical polymerization. The influence of various parameters, such as the feed ratio, the concentration of immobilized bromoester groups, and the presence of a spacer group on the poly(methyl methacrylate) loading, was studied. Monoliths with capacities of up to 7 mmol g,1 were obtained. Thermogravimetric analyses, scanning electron microscopy experiments, and mercury intrusion porosimetry measurements were used for the characterization of the final materials. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1216,1226, 2004 [source]

Center for Synchrotron Biosciences' U2B beamline: an international resource for biological infrared spectroscopy

JOURNAL OF SYNCHROTRON RADIATION, Issue 4 2002
N. S. Marinkovic
A synchrotron infrared (IR) beamline, U2B, dedicated to the biomedical and biological sciences has been constructed and is in operation at the National Synchrotron Light Source (NSLS) of Brookhaven National Laboratory. The facility is operated by the Center for Synchrotron Biosciences of the Albert Einstein College of Medicine in cooperation with the NSLS. Owing to the broadband nature of the synchrotron beam with brightness 1000 times that of conventional sources, Fourier transform IR spectroscopy experiments are feasible on diffraction-limited sample areas at high signal-to-noise ratios and with relatively short data-acquisition times. A number of synchrotron IR microscopy experiments that have been performed in the mid-IR spectral range (500,5000,cm,1) are summarized, including time-resolved protein-folding studies in the microsecond time regime, IR imaging of neurons, bone and other biological tissues, as well as imaging of samples of interest in the chemical and environmental sciences. Owing to the high flux output of this beamline in the far-IR region (50,500,cm,1), investigations of hydrogen bonding and dynamic molecular motions of biomolecules have been carried out from 10 to 300,K using a custom-made cryostat and an evacuated box. This facility is intended as an international resource for biological IR spectroscopy fully available to outside users based on competitive proposal. [source]

Keratin-lipid structural organization in the corneous layer of snake,

BIOPOLYMERS, Issue 12 2009
Alberto Ripamonti
Abstract The shed epidermis (molt) of snakes comprises four distinct layers. The upper two layers, here considered as ,-layer, contain essentially ,-keratin. The following layer, known as mesos-layer, is similar to the human stratum corneum, and is formed by thin cells surrounded by intercellular lipids. The latter layer mainly contains ,-keratin. In this study, the molecular assemblies of proteins and lipids contained in these layers have been analyzed in the scale of two species of snakes, the elapid Tiger snake (TS, Notechis scutatus) and the viperid Gabon viper (GV, Bitis gabonica). Scanning X-ray micro-diffraction, FTIR and Raman spectroscopies, thermal analysis, and scanning electron microscopy experiments confirm the presence of the three layers in the GV skin scale. Conversely, in the TS molt a typical ,-keratin layer appears to be absent. In the latter, experimental data suggest the presence of two domains similar to those found in the lipid intercellular matrix of stratum corneum. X-ray diffraction data also allow to determine the relative orientation of keratins and lipids. The keratin fibrils are randomly oriented inside the layers parallel to the surface of scales while the lipids are organized in lamellar structures having aliphatic chains normal to the scale surface. The high ordered lipid organization in the mature mesos layer probably increases its effectiveness in limiting water-loss. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 1172,1181, 2009. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source]