295 research outputs found
Impacts of International Wheat Breeding Research in Developing Countries, 1966-97
Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,
Tripoli : on the shores of Tripoli
https://digitalcommons.library.umaine.edu/mmb-vp/2606/thumbnail.jp
That\u27s How I Believe In You
https://digitalcommons.library.umaine.edu/mmb-vp/6241/thumbnail.jp
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Mesophase Separation and Probe Dynamics in Protein-Polyelectrolyte Coacervates
Protein–polyelectrolyte coacervates are self-assembling macroscopically monophasic biomacromolecular fluids whose unique properties arise from transient heterogeneities. The structures of coacervates formed at different conditions of pH and ionic strength from poly(dimethyldiallylammonium chloride) and bovine serum albumin (BSA), were probed using fluorescence recovery after photobleaching. Measurements of self-diffusion in coacervates were carried out using fluorescein-tagged BSA, and similarly tagged Ficoll, a non-interacting branched polysaccharide with the same size as BSA. The results are best explained by temporal and spatial heterogeneities, also inferred from static light scattering and cryo-TEM, which indicate heterogeneous scattering centers of several hundred nm. Taken together with previous dynamic light scattering and rheology studies, the results are consistent with the presence of extensive dilute domains in which are embedded partially interconnected 50–700 nm dense domains. At short length scales, protein mobility is unobstructed by these clusters. At intermediate length scales, proteins are slowed down due to tortuosity effects within the blind alleys of the dense domains, and to adsorption at dense/dilute domain interfaces. Finally, at long length scales, obstructed diffusion is alleviated by the break-up of dense domains. These findings are discussed in terms of previously suggested models for protein–polyelectrolyte coacervates. Possible explanations for the origin of mesophase separation are offered
Raman spectroscopy of a single ion coupled to a high-finesse cavity
We describe an ion-based cavity-QED system in which the internal dynamics of
an atom is coupled to the modes of an optical cavity by vacuum-stimulated Raman
transitions. We observe Raman spectra for different excitation polarizations
and find quantitative agreement with theoretical simulations. Residual motion
of the ion introduces motional sidebands in the Raman spectrum and leads to ion
delocalization. The system offers prospects for cavity-assisted
resolved-sideband ground-state cooling and coherent manipulation of ions and
photons.Comment: 8 pages, 6 figure
Primary myxoid liposarcoma of the supraglottic larynx
Sarcomas are a rare occurrence accounting for roughly 1% of all cancer cases reported. Of these, 9–18% will be identified as liposarcoma. Overall, only 4–9% of all liposarcomas occur in the head and neck region. As such, it is a rare event to see a primary liposarcoma of the aerodigestive tract. These tumors are typically misdiagnosed secondary to their indolent, asymptomatic course and similarities in appearance to other benign lesions. An understanding of these lesions will help clinicians appropriately manage their patients. We present a case of a 60-year male with a primary supraglottic myxoid liposarcoma, and provide relevant information about liposarcomas
Suitability of linear quadrupole ion traps for large Coulomb crystals
Growing and studying large Coulomb crystals, composed of tens to hundreds of
thousands of ions, in linear quadrupole ion traps presents new challenges for
trap implementation. We consider several trap designs, first comparing the
total driven micromotion amplitude as a function of location within the
trapping volume; total micromotion is an important point of comparison since it
can limit crystal size by transfer of radiofrequency drive energy into thermal
energy. We also compare the axial component of micromotion, which leads to
first-order Doppler shifts along the preferred spectroscopy axis in precision
measurements on large Coulomb crystals. Finally, we compare trapping potential
anharmonicity, which can induce nonlinear resonance heating by shifting normal
mode frequencies onto resonance as a crystal grows. We apply a non-deforming
crystal approximation for simple calculation of these anharmonicity-induced
shifts, allowing a straightforward estimation of when crystal growth can lead
to excitation of different nonlinear heating resonances. In the axial
micromotion and anharmonicity points of comparison, we find significant
differences between the compared trap designs, with an original rotated-endcap
trap performing slightly better than the conventional in-line endcap trap
Rapid automatic assessment of microvascular density in sidestream dark field images
The purpose of this study was to develop a rapid and fully automatic method for the assessment of microvascular density and perfusion in sidestream dark field (SDF) images. We modified algorithms previously developed by our group for microvascular density assessment and introduced a new method for microvascular perfusion assessment. To validate the new algorithm for microvascular density assessment, we reanalyzed a selection of SDF video clips (n = 325) from a study in intensive care patients and compared the results to (semi-)manually found microvascular densities. The method for microvascular perfusion assessment (temporal SDF image contrast analysis, tSICA) was tested in several video simulations and in one high quality SDF video clip where the microcirculation was imaged before and during circulatory arrest in a cardiac surgery patient. We found that the new method for microvascular density assessment was very rapid (<30 s/clip) and correlated excellently with (semi-)manually measured microvascular density. The new method for microvascular perfusion assessment (tSICA) was shown to be limited by high cell densities and velocities, which severely impedes the applicability of this method in real SDF images. Hence, here we present a validated method for rapid and fully automatic assessment of microvascular density in SDF images. The new method was shown to be much faster than the conventional (semi-)manual method. Due to current SDF imaging hardware limitations, we were not able to automatically detect microvascular perfusion
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