2,626 research outputs found
Cooperativity and Frustration in Protein-Mediated Parallel Actin Bundles
We examine the mechanism of bundling of cytoskeletal actin filaments by two
representative bundling proteins, fascin and espin. Small-angle X-ray studies
show that increased binding from linkers drives a systematic \textit{overtwist}
of actin filaments from their native state, which occurs in a linker-dependent
fashion. Fascin bundles actin into a continuous spectrum of intermediate twist
states, while espin only allows for untwisted actin filaments and
fully-overtwisted bundles. Based on a coarse-grained, statistical model of
protein binding, we show that the interplay between binding geometry and the
intrinsic \textit{flexibility} of linkers mediates cooperative binding in the
bundle. We attribute the respective continuous/discontinous bundling mechanisms
of fascin/espin to differences in the stiffness of linker bonds themselves.Comment: 5 pages, 3 figures, figure file has been corrected in v
Conventional solid-state fermentation impacts the white lupin proteome reducing the abundance of allergenic peptides
The demand for high-quality and sustainable protein sources is on the rise. Lupin is an emerging plant-based source of protein with health-enhancing properties; however, the allergenic potential of lupins limits their widespread adoption in food products. A combination of discovery and targeted quantitative proteome measurements was used to investigate the impact of solid-state fermentation induced by Rhizopus oligosporus on the proteome composition and allergenic protein abundances of white lupin seed. In total, 1,241 proteins were uniquely identified in the fermented sample. Moreover, the effectiveness of the solid-state fermentation in reducing the abundance of the tryptic peptides derived from white lupin allergens was demonstrated. Comparably, a greater decrease was noted for the major white lupin allergen based on -conglutin peptide abundances. Hence, conventional solid-state fermentation processing can be beneficial for reducing the potential allergenicity of lupin-based foods. This finding will open new avenues for unlocking the potential of this under-utilised legume
G91-1026 Sunflower Production in Nebraska
Seeds, seedbed preparations, fertilizing and controlling weeds in sunflowers are among the topics covered here. Sunflowers are native to Nebraska. Cultivated for centuries by native American Indians as a food crop, sunflowers were taken to Europe in the mid-16th century. Oilseed sunflowers have been a U.S. crop since 1986. Sunflower production is divided into two market classes, oil and confectionery. The oil type is by far the most commonly grown market class. Recent health trends have brought sunflower cooking oil into prominence because the oil is low in saturated fats. Confectionery types are grown for the edible roasted sunflower seed market, and are produced under strict contract guidelines. Seed size is critical, with small seeds designated for bird seed market channels. Growing the confectionery type without a contract is risky. Sunflower production of both market classes is currently around 30,000 acres in Nebraska. Recently a third market class has started to develop based on high oleic acid content, which gives products better shelf life
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The Role of Temporal Evolution in Modeling Atmospheric Emissions from Tropical Fires
Fire emissions associated with tropical land use change and maintenance influence atmospheric composition, air quality, and climate. In this study, we explore the effects of representing fire emissions at daily versus monthly resolution in a global composition-climate model. We find that simulations of aerosols are impacted more by the temporal resolution of fire emissions than trace gases such as carbon monoxide or ozone. Daily-resolved datasets concentrate emissions from fire events over shorter time periods and allow them to more realistically interact with model meteorology, reducing how often emissions are concurrently released with precipitation events and in turn increasing peak aerosol concentrations. The magnitude of this effect varies across tropical ecosystem types, ranging from smaller changes in modeling the low intensity, frequent burning typical of savanna ecosystems to larger differences when modeling the short-term, intense fires that characterize deforestation events. The utility of modeling fire emissions at a daily resolution also depends on the application, such as modeling exceedances of particulate matter concentrations over air quality guidelines or simulating regional atmospheric heating patterns
Performance Testing of a Novel Off-plane Reflection Grating and Silicon Pore Optic Spectrograph at PANTER
An X-ray spectrograph consisting of radially ruled off-plane reflection
gratings and silicon pore optics was tested at the Max Planck Institute for
extraterrestrial Physics PANTER X-ray test facility. The silicon pore optic
(SPO) stack used is a test module for the Arcus small explorer mission, which
will also feature aligned off-plane reflection gratings. This test is the first
time two off-plane gratings were actively aligned to each other and with a SPO
to produce an overlapped spectrum. The gratings were aligned using an active
alignment module which allows for the independent manipulation of subsequent
gratings to a reference grating in three degrees of freedom using picomotor
actuators which are controllable external to the test chamber. We report the
line spread functions of the spectrograph and the actively aligned gratings,
and plans for future development.Comment: Draft Version March 19, 201
SODA: Bottleneck Diffusion Models for Representation Learning
We introduce SODA, a self-supervised diffusion model, designed for
representation learning. The model incorporates an image encoder, which
distills a source view into a compact representation, that, in turn, guides the
generation of related novel views. We show that by imposing a tight bottleneck
between the encoder and a denoising decoder, and leveraging novel view
synthesis as a self-supervised objective, we can turn diffusion models into
strong representation learners, capable of capturing visual semantics in an
unsupervised manner. To the best of our knowledge, SODA is the first diffusion
model to succeed at ImageNet linear-probe classification, and, at the same
time, it accomplishes reconstruction, editing and synthesis tasks across a wide
range of datasets. Further investigation reveals the disentangled nature of its
emergent latent space, that serves as an effective interface to control and
manipulate the model's produced images. All in all, we aim to shed light on the
exciting and promising potential of diffusion models, not only for image
generation, but also for learning rich and robust representations
Application of nanoimprinting technique for fabrication of trifocal diffractive lens with sine-like radial profile
The fabrication of submicron-height sine-like relief of a trifocal diffractive zone plate using a nanoimprinting technique is studied. The zone plate is intended for use in combined trifocal diffractive-refractive lenses and provides the possibility to form trifocal intraocular lenses with predetermined light intensity distribution between foci. The optical properties of the designed zone plate having the optical powers 3 D, 0, -3D in the three main diffraction orders are theoretically and experimentally investigated. The results of the theoretical investigations are in good agreement with experimental measurements. The effects of the pupil size (lens diameter) as well as the wavelength-dependent behavior of the zone plate are also discussed
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El Niño and health risks from landscape fire emissions in southeast Asia
Emissions from landscape fires affect both climate and air quality. Here, we combine satellite-derived fire estimates and atmospheric modelling to quantify health effects from fire emissions in southeast Asia from 1997 to 2006. This region has large interannual variability in fire activity owing to coupling between El Niño-induced droughts and anthropogenic land-use change. We show that during strong El Niño years, fires contribute up to 200 μg m−3 and 50 ppb in annual average fine particulate matter (PM2.5) and ozone surface concentrations near fire sources, respectively. This corresponds to a fire contribution of 200 additional days per year that exceed the World Health Organization 50 μg m−3 24-hr PM2.5 interim target and an estimated 10,800 (6,800–14,300)-person (~ 2%) annual increase in regional adult cardiovascular mortality. Our results indicate that reducing regional deforestation and degradation fires would improve public health along with widely established benefits from reducing carbon emissions, preserving biodiversity and maintaining ecosystem services
Factors Influencing Pseudo-Accommodation—The Difference between Subjectively Reported Range of Clear Focus and Objectively Measured Accommodation Range
The key determinants of the range of clear focus in pre-presbyopes and their relative contributions to the difference between subjective range of focus and objective accommodation assessments have not been previously quantified. Fifty participants (aged 33.0 ± 6.4 years) underwent simultaneous monocular subjective (visual acuity measured with an electronic test-chart) and objective (dynamic accommodation measured with an Aston open-field aberrometer) defocus curve testing for lenses between +2.00 to −10.00 DS in +0.50 DS steps in a randomized order. Pupil diameter and ocular aberrations (converted to visual metrics normalized for pupil size) at each level of blur were measured. The difference between objective range over which the power of the crystalline lens changes and the subjective range of clear focus was quantified and the results modelled using pupil size, refractive error, tolerance to blur, and ocular aberrations. The subjective range of clear focus was principally accounted for by age (46.4%) and pupil size (19.3%). The objectively assessed accommodative range was also principally accounted for by age (27.6%) and pupil size (15.4%). Over one-quarter (26.0%) of the difference between objective accommodation and subjective range of clear focus was accounted for by age (14.0%) and spherical aberration at maximum accommodation (12.0%). There was no significant change in the objective accommodative response (F = 1.426, p = 0.229) or pupil size (F = 0.799, p = 0.554) of participants for levels of defocus above their amplitude of accommodation. Pre-presbyopes benefit from an increased subjective range of clear vision beyond their objective accommodation due in part to neural factors, resulting in a measured depth-of-focus of, on average, 1.0
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