895 research outputs found
Measuring Pancharatnam's relative phase for SO(3) evolutions using spin polarimetry
In polarimetry, a superposition of internal quantal states is exposed to a
single Hamiltonian and information about the evolution of the quantal states is
inferred from projection measurements on the final superposition. In this
framework, we here extend the polarimetric test of Pancharatnam's relative
phase for spin proposed by Wagh and Rakhecha [Phys. Lett. A {\bf 197},
112 (1995)] to spin undergoing noncyclic SO(3) evolution. We
demonstrate that the output intensity for higher spin values is a polynomial
function of the corresponding spin intensity. We further propose a
general method to extract the noncyclic SO(3) phase and visibility by rigid
translation of two spin flippers. Polarimetry on higher spin states
may in practice be done with spin polarized atomic beams.Comment: New title, minor corrections, journal reference adde
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Critical Percolation Threshold for Solvation-Site Connectivity in Polymer Electrolyte Mixtures
Poly(ethylene oxide) (PEO)-based polymer electrolytes are often mixed with rigid, nonconductive polymers to improve mechanical strength. The suppressed conductivity of the mixture typically arises from a reduced segmental mobility and a diminished connectivity between conductive PEO sites. To decouple these two mechanisms, we compare transport in symmetric miscible blends and disordered block copolymers (BCP) of PEO and poly(methyl methacrylate) (PMMA). Because the two systems have identical physicochemical properties, differences in their conductivity directly reflect the underlying PEO network connectivity. We find that, at short distances (+ solvation networks are identical for the two systems; however, a distinct variation in the network connectivity arises at length scales between 5 and 10 Å. Specifically, the BCP exhibits a lower connectivity, and therefore a lower conductivity than the blend. A quantitative model is proposed that associates long-range Li+ transport with local miscibility; the concept of network connectivity discussed here could be useful for designing polymer electrolyte systems
Cytosolic activation of cell death and stem rust resistance by cereal MLA-family CC-NLR proteins
Plants possess intracellular immune receptors designated “nucleotidebinding domain and leucine-rich repeat” (NLR) proteins that translate
pathogen-specific recognition into disease-resistance signaling. The wheat immune receptors Sr33 and Sr50 belong to the class
of coiled-coil (CC) NLRs. They confer resistance against a broad spectrum of field isolates of Puccinia graminis f. sp. tritici, including
the Ug99 lineage, and are homologs of the barley powdery mildewresistance proteinMLA10. Here, we showthat, similarly to MLA10, the
Sr33 and Sr50 CC domains are sufficient to induce cell death in Nicotiana benthamiana. Autoactive CC domains and full-length
Sr33 and Sr50 proteins self-associate in planta. In contrast, truncated CC domains equivalent in size to an MLA10 fragment for which a crystal structure was previously determined fail to induce
cell death and do not self-associate. Mutations in the truncated region also abolish self-association and cell-death signaling. Analysis of Sr33 and Sr50 CC domains fused to YFP and either nuclear
localization or nuclear export signals in N. benthamiana showed that cell-death induction occurs in the cytosol. In stable transgenic
wheat plants, full-length Sr33 proteins targeted to the cytosol provided rust resistance, whereas nuclear-targeted Sr33 was not functional. These data are consistent with CC-mediated induction
of both cell-death signaling and stem rust resistance in the cytosolic compartment, whereas previous research had suggested that
MLA10-mediated cell-death and disease resistance signaling occur independently, in the cytosol and nucleus, respectively
A new application of pelvis area data as culling tool to aid in the management of dystocia in heifers
Although fetomaternal disproportion is
the major cause of dystocia in heifers, pelvis area (PA)
is not recommended as a culling tool due to its relatively
low importance and genetic correlation with calf birth
weight (BWT), the most important factor associated
with dystocia. The objective of this observational study
of 484 limited bred yearling beef heifers was to compare
the effects of different methods of adjustment of PA data
for culling to select against dystocia. Multivariable analyses
were used to determine predictors of PA, calf BWT,
and dystocia. Hypothetical culling rates of 10 and 20%
were then applied after ranking heifers by each of the
following: unadjusted PA, PA adjusted to 365 d of age by
subtracting 0.27 cm2 per day of age difference between
each heifer’s age and 365 d (APA), PA:prebreeding
BW ratio (PA:BW), PA adjusted to the median BW of
the group using the regression coefficient of PA on BW
within age group (BWPA), and PA similarly adjusted to
the median lean BW (LBWPA). Dam parity, sire, prebreeding
age, prebreeding BW, and prebreeding BCS
were associated with PA whereas dam parity, sire, own BWT, PA, AI bull, and calf gender were associated with
calf BWT (P < 0.05). Dam parity, calf BWT, and either
BWPA or LBWPA were the only independent predictors
of dystocia (P < 0.05). Adjusting PA to BW or lean BW
(LBW) improved the sensitivity and specificity to predict
dystocia. After hypothetical culling by PA, retained
heifers were heavier and had a higher calving rate and
calves tended to be heavier at birth compared to culled
heifers, but dystocia rates were not different. Culling by
APA resulted in similar effects, except that dystocia rate
tended to be lower in retained heifers. Culling by PA:BW
resulted in lower dystocia rate in retained than in culled
heifers, but retained heifers had lower prebreeding BW
than culls. Culling by BWPA and LBWPA resulted in
lower proportions with dystocia and a tendency towards
higher calving rates in the retained heifers, without affecting
the prebreeding BW or calf BWT. It is concluded that
pelvimetry is a useful culling tool to aid in the management
of dystocia in yearling heifers and that adjustment
of PA to median BW or LBW within age group improves
its accuracy and avoids the undesirable side effects.http://www.animal-science.org/hb201
Development of a comparative genomic fingerprinting assay for rapid and high resolution genotyping of Arcobacter butzleri
Sherpa Romeo green journal. Open access, distributed under the terms of the Creative Commons Attribution (CC-BY) License.Background
Molecular typing methods are critical for epidemiological investigations, facilitating disease outbreak detection and source identification. Study of the epidemiology of the emerging human pathogen Arcobacter butzleri is currently hampered by the lack of a subtyping method that is easily deployable in the context of routine epidemiological surveillance. In this study we describe a comparative genomic fingerprinting (CGF) method for high-resolution and high-throughput subtyping of A. butzleri. Comparative analysis of the genome sequences of eleven A. butzleri strains, including eight strains newly sequenced as part of this project, was employed to identify accessory genes suitable for generating unique genetic fingerprints for high-resolution subtyping based on gene presence or absence within a strain.
Results
A set of eighty-three accessory genes was used to examine the population structure of a dataset comprised of isolates from various sources, including human and non-human animals, sewage, and river water (n=156). A streamlined assay (CGF40) based on a subset of 40 genes was subsequently developed through marker optimization. High levels of profile diversity (121 distinct profiles) were observed among the 156 isolates in the dataset, and a high Simpson’s Index of Diversity (ID) observed (ID > 0.969) indicate that the CGF40 assay possesses high discriminatory power. At the same time, our observation that 115 isolates in this dataset could be assigned to 29 clades with a profile similarity of 90% or greater indicates that the method can be used to identify clades comprised of genetically similar isolates.
Conclusions
The CGF40 assay described herein combines high resolution and repeatability with high throughput for the rapid characterization of A. butzleri strains. This assay will facilitate the study of the population structure and epidemiology of A. butzleri.Ye
Differentiation of Human Induced Pluripotent Stem Cells into Keratinocytes
Investigating basic biological mechanisms underlying human diseases relies on the availability of sufficient quantities of patient cells. As most primary somatic cells have a limited lifespan, obtaining sufficient material for biological studies has been a challenge. The development of induced pluripotent stem cell (iPSC) technology has been a game changer, especially in the field of rare genetic disorders. iPSC are essentially immortal, can be stored indefinitely, and can thus be used to generate defined somatic cells in unlimited quantities. Further, the availability of genome editing technologies, such as CRISPR/CAS, has provided us with the opportunity to create “designer� iPSC lines with defined genetic characteristics. A major advancement in biological research stems from the development of methods to direct iPSC differentiation into defined cell types. In this article, we provide the basic protocol for the generation of human iPSC-derived keratinocytes (iPSC-K). These cells have the characteristics of basal epidermal keratinocytes and represent a tool for the investigation of normal epidermal biology, as well as genetic and acquired skin disorders. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC.Wiley Open Access Accoun
Markers of assimilation of problematic experiences in dementia within the LivDem project
© 2015, © The Author(s) 2015. This study aimed to determine whether the Markers of Assimilation of Problematic Experiences in Dementia scale (MAPED) can be used to identify whether the way in which participants talk about dementia changed during the group. All eight sessions of a LivDem group, which were attended by participants were recorded and transcribed. An initial analysis identified 160 extracts, which were then rated using the MAPED system. Inter-rater reliability was 61% and following a resolution meeting, 35 extracts were discarded, leaving 125 extracts with an agreed marker code. All of the participants were identified as producing a speech marker relating to dementia, and these varied between 0 (warding off) to 6 (problem solution). Examples of these markers are provided. The proportion of emergence markers (indicating the initial stages of assimilation) compared to later markers changed significantly between the first four sessions and the final sessions. This difference was still significant even when the markers produced by the most verbal participant, Graham, were excluded. The use of process measures within psychotherapy complements more conventional outcome measures and has both theoretical and clinical implications
Dephasing in Disordered Conductors due to Fluctuating Electric Fields
We develop a novel eikonal expansion for the Cooperon to study the effect of
space- and time-dependent electric fields on the dephasing rate of disordered
conductors. For randomly fluctuating fields with arbitrary covariance we derive
a general expression for the dephasing rate which is free of infrared
divergencies in reduced dimensions. For time-dependent external fields with
finite wavelength and sufficiently small amplitude we show that the dephasing
rate is proportional to the square root of the electromagnetic power coupled
into the system, in agreement with data by Wang and Lindelof [Phys. Rev. Lett.
{\bf{59}}, 1156 (1987)].Comment: 17 Latex-pages, one figure; we now give more technical details and
discuss the screening problem more carefully; to appear in Phys. Rev.
Granulovirus PK-1 kinase activity relies on a side-to-side dimerization mode centered on the regulatory αC helix
The life cycle of Baculoviridae family insect viruses depends on the viral protein kinase, PK-1, to phosphorylate the regulatory protein, p6.9, to induce baculoviral genome release. Here, we report the crystal structure of Cydia pomenella granulovirus PK-1, which, owing to its likely ancestral origin among host cell AGC kinases, exhibits a eukaryotic protein kinase fold. PK-1 occurs as a rigid dimer, where an antiparallel arrangement of the αC helices at the dimer core stabilizes PK-1 in a closed, active conformation. Dimerization is facilitated by C-lobe:C-lobe and N-lobe:N-lobe interactions between protomers, including the domain-swapping of an N-terminal helix that crowns a contiguous β-sheet formed by the two N-lobes. PK-1 retains a dimeric conformation in solution, which is crucial for catalytic activity. Our studies raise the prospect that parallel, side-to-side dimeric arrangements that lock kinase domains in a catalytically-active conformation could function more broadly as a regulatory mechanism among eukaryotic protein kinases
A randomised control crossover trial of a theory based intervention to improve sun-safe and healthy behaviours in construction workers:Study protocol
Abstract Background Exposure to sunlight can have both positive and negative health impacts. Excessive exposure to ultra-violet (UV) radiation from the sun can cause skin cancer, however insufficient exposure to sunlight has a detrimental effect on production of Vitamin D. In the construction industry there are onsite proactive behaviours for safety, but sun-safety remains a low priority. There is limited research on understanding the barriers to adopting sun-safe behaviours and the association this may have with Vitamin D production. This paper reports a protocol for an intervention study, using text messaging in combination with a supportive smartphone App. The intervention aims to both reduce UV exposure during months with higher UV levels and promote appropriate dietary changes to boost Vitamin D levels during months with low UV levels. Method/design Approximately 60 construction workers will be recruited across the United Kingdom. A randomised control crossover trial (RCCT) will be used to test the intervention, with randomisation at site level – i.e. participants will receive both the control (no text messages or supportive App support) and intervention (daily text messages and supportive App). Using the Theory of Planned Behaviour (TPB) the intervention focuses on supporting sun-safety and healthy dietary decisions in relation to Vitamin D intake. The intervention emphasises cultivating the perception of normative support in the workplace, increasing awareness of control and self-efficacy in taking sun-protective behaviours, making healthier eating choices to boost Vitamin D, and tackling stigmas attached to image and group norms. Each study epoch will last 21 days with intervention text messages delivered on workdays only. The supportive App will provide supplementary information about sun protective behaviours and healthy dietary choices. The primary outcome measure is 25-hydroxy-Vitamin D [25(OH)D] level (obtained using blood spot sampling), which will be taken pre and post control and intervention periods. Secondary outcome measures are two-fold, (1) using the TPB to detect changes in behaviour, and (2) quantifying UV exposure during the UK peak radiation season (April–September) using body-mounted UV sensors. Discussion This study will provide important information about the effectiveness of a technology-based intervention to promote sun-safety and healthy behaviours in outdoor construction workers. Trial registration ISRCTN15888934 retrospectively registered 15.01.2018
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