Confocal Raman spectroscopy was applied to the characterization of various states emerging in the screening of protein crystallization. Four main characterized states, namely single crystals, microcrystals, precipitates, and clear drops without solid materials, appear in a droplet for crystallization; the first three states should be critically distinguished and characterized because of the limitations of visual observation under an optical microscope. Using lysozyme and other proteins, crystallization was performed by the hanging drop vapor diffusion technique and was monitored through an automated confocal Raman system. Prior to the spectroscopic analysis, an optical microscope with a charge-coupled device (CCD) camera and associated image processing software were used to rapidly identify the XY locations to be measured spectroscopically by focusing the laser beam on a test sample. Instead of the current image analysis by optical microscopy, confocal Raman spectroscopy with a high spatial resolution was used to identify the state of protein crystallization. Such real-time Raman monitoring also distinguished real protein crystals from pseudo-protein crystals emerging in a crystallization droplet.
We consider the polarization of unstable type-IIB D0-branes in the presence of a background five-form field strength. This phenomenon is studied from the point of view of the leading terms in the non-abelian Born Infeld action of the unstable D0-branes. The equations have SO(4) invariant solutions describing a non-commutative 3-sphere, which becomes a classical 3-sphere in the large-N limit. We discuss the interpretation of these solutions as spherical D3-branes. The tachyon plays a tantalizingly geometrical role in relating the fuzzy S 3 geometry to that of a fuzzy S 4 .
Co–Cr–Ta/Cr bilayered films for longitudinal recording disks were deposited by facing targets sputtering (FTS) on 2.5 in. and ultraflat disk substrates of durable single-crystal silicon at temperature Ts of 100 °C and Ar pressure PAr of 0.2 mTorr. TEM observation of the films revealed ultrafine microstructures, and grain boundaries were unclear. The noise and recording characteristics of those disks were comparable with those of very high-performance disks with Co–Cr–Pt films, with coercivity Hc of 2.4 kOe, employed as a reference, even though the Co–Cr–Ta films exhibited macroscopic Hc of only 800 Oe. In this study, Co85Cr13Ta2/Cr bilayered films with the same composition as the above-mentioned disks were deposited by plasma-enhanced (PEFTS) on 2.5 in. and glass–ceramic substrates with ultraflat surface and tough durability at Ts of 100 °C to obtain better microstructure, signal-to-noise ratio (SNR), and surface flatness, with consequent lower flying height, than those on Si substrates, thus making it possible to fabricate ultrahigh-density recording disks. The PEFTS apparatus has several outstanding advantages such as plasma-free substrates, low background pressure of 5×10−7 Torr, low PAr of 0.1 mTorr, and higher mobility of the adatoms than in conventional FTS because of the proximity of the substrate to the central axis of the targets, indicating uniform plasma distribution, with up to six target units in a vacuum chamber. The film’s surface roughness Ra of 0.7 nm and the high mobility of the adatoms result in narrow grain boundaries without pores and inclusions, which were observed by TEM, and better overwrite performance than that of Si substrates and the same SNR as Si substrates, which were measured with a read/write test stand. These results will allow practical application in ultrahigh-density recording systems, including 1 in. microdrives.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.