12,567 research outputs found
The changing role of cell culture in the generation of transgenic livestock
Transgenesis may allow the generation of farm animals with altered phenotype, animal models for research and animal bioreactors. Although such animals have been produced, the time and expense involved in generating transgenic livestock and then evaluating the transgene expression pattern is very restrictive. If questions about the ability and efficiency of expression could be asked solely in vitro rapid progress could be achieved. Unfortunately, experiments addressing transcriptional control in vitro have proved unreliable in their ability to indicate whether a transgene will be transcribed or not. However, initial studies suggest that cell culture may be able to predict in vivo post-transcriptional events. We review these issues and propose that strategies which engineer the transgene integration site could enhance the probability for efficient expression. This approach has now become feasible with the development of techniques allowing animals to be generated from somatic cells by nuclear transfer. The important step in this procedure is the use of cells grown in culture as the source of genetic information, allowing the selection of specific transgene integration events. This technology which has dramatically increased the potential use of transgenic livestock for both agricultural and biotechnological applications, is based on standard cell culture methodology. We are now at the start of a new era in large animal transgenics
Polyaryl ethers and related polysiloxane copolymer molecular coatings preparation and radiation degrdation
Poly(arylene ether sulfones) comprise a class of materials known as engineering thermoplastics which have a variety of important applications. These polymers are tough, rigid materials with good mechanical properties over a wide temperature range, and they are processed by conventional methods into products typically having excellent hydrolytic, thermal, oxidative and dimensional stability. Wholly aromatic random copolymers of hydroquinone and biphenol with 4.4 prime dichlorodiphenyl sulfone were synthesized via mechanical nucleophilic displacement. Their structures were characterized and mechanical behavior studied. These tough, ductile copolymers show excellent radiation resistance to electron beam treatment and retain much of the mechanical properties up to at least 700 Mrads under argon
Influence of static Jahn-Teller distortion on the magnetic excitation spectrum of PrO2: A synchrotron x-ray and neutron inelastic scattering study
A synchrotron x-ray diffraction study of the crystallographic structure of
PrO2 in the Jahn-Teller distorted phase is reported. The distortion of the
oxygen sublattice, which was previously ambiguous, is shown to be a chiral
structure in which neighbouring oxygen chains have opposite chiralities. A
temperature dependent study of the magnetic excitation spectrum, probed by
neutron inelastic scattering, is also reported. Changes in the energies and
relative intensities of the crystal field transitions provide an insight into
the interplay between the static and dynamic Jahn-Teller effects.Comment: 7 pages, 6 figure
Optimising Bowel Cancer Screening Phase 1: Optimising the cost effectiveness of repeated FIT screening and screening strategies combining bowel scope and FIT screening
ScHARR has been commissioned by the UK National Screening Committee (NSC) to consider the costeffectiveness
and endoscopy capacity requirements of a variety of different screening options incorporating
faecal immunochemical testing (FIT) and bowel scope (BS) within the Bowel Cancer Screening Programme
(BCSP).
An existing cost-effectiveness model was used. The model was refined considerably, new data included and
model validation was undertaken. All FIT thresholds between 20 and 180 µg/ml were modelled. Analyses were
undertaken to determine which screening strategies involving repeated FIT screening and/or bowel scope are
most cost-effective given endoscopy constraints.
Note that the conclusions reached are based on optimising cost-effectiveness where effectiveness is measured
in terms of QALYs gained. If the aim was to optimise QALY gains or CRC incidence/mortality reduction then
conclusions would be different.
The analysis without endoscopy constraints indicates that the most cost effective screening strategy is the one
which delivers the most intensive screening. Regardless of capacity constraints the current screening
strategies (gFOBT 2-yearly 60-74 with or without bowel scope age 55) are dominated by a FIT screening
strategy (i.e. a FIT strategy exists which is more effective and less expensive).
For repeated FIT screening it is recommended that the screening interval is kept to 2-yearly screening.
However, increased benefits may be obtained by re-inviting non-attenders after a 1 year interval. The optimal
starting age for a repeated FIT screening strategy is 50 or 51 hence it is suggested that the screening start age
is reduced compared to what is currently used in the BCSP. The optimal upper screening age varies between
65 and 74, depending on the capacity constraint used. The optimal FIT threshold depends on the available
capacity for screening referral colonoscopies. With 50,000 screening referral colonoscopies (current capacity)
then we recommend a strategy of 2-yearly, age 51-65, FIT161 (8 screens). With 70,000 screening referral
colonoscopies (current capacity) then we recommend a strategy of: 2-yearly, age 50-70, FIT153 (11 screens). If
90,000 screening referral colonoscopies is considered feasible to achieve in the future then we recommend a
strategy of 2-yearly, age 50-74, FIT124 (13 screens).
In terms of bowel scope screening the model found uncertainty in whether it is cost effective to replace one
FIT screen with a one-off bowel scope at age 58/59. However, a repeated FIT screening strategy requiring
125k screening referral colonoscopies annually would be far more effective and cost effective than a one-off
bowel scope at age 59. Such strategies could be considered to have equivalent ‘endoscopy capacity’ (assuming
that 10 bowel scopes and 4 screening referral colonoscopies are equivalent ).Hence, if bowel scope capacity
could be used for undertaking screening referral colonoscopies this would result in higher effectiveness and
cost-effectiveness
Deterministic entanglement and tomography of ion spin qubits
We have implemented a universal quantum logic gate between qubits stored in
the spin state of a pair of trapped calcium 40 ions. An initial product state
was driven to a maximally entangled state deterministically, with 83% fidelity.
We present a general approach to quantum state tomography which achieves good
robustness to experimental noise and drift, and use it to measure the spin
state of the ions. We find the entanglement of formation is 0.54.Comment: 3 figures, 4 pages, footnotes fixe
Long-lived mesoscopic entanglement outside the Lamb-Dicke regime
We create entangled states of the spin and motion of a single Ca
ion in a linear ion trap. The motional part consists of coherent states of
large separation and long coherence time. The states are created by driving the
motion using counterpropagating laser beams. We theoretically study and
experimentally observe the behaviour outside the Lamb-Dicke regime, where the
trajectory in phase space is modified and the coherent states become squeezed.
We directly observe the modification of the return time of the trajectory, and
infer the squeezing. The mesoscopic entanglement is observed up to with coherence time 170 microseconds and mean phonon excitation
\nbar = 16.Comment: 5 pages, 3 figures. Revised version after editor comment
Ground-state cooling of a trapped ion Using long-wavelength radiation
We demonstrate ground-state cooling of a trapped ion using radio-frequency (rf) radiation. This is a powerful tool for the implementation of quantum operations, where rf or microwave radiation instead of lasers is used for motional quantum state engineering. We measure a mean phonon number of n¯=0.13(4) after sideband cooling, corresponding to a ground-state occupation probability of 88(7)%. After preparing in the vibrational ground state, we demonstrate motional state engineering by driving Rabi oscillations between the |n=0⟩ and |n=1⟩ Fock states. We also use the ability to ground-state cool to accurately measure the motional heating rate and report a reduction by almost 2 orders of magnitude compared with our previously measured result, which we attribute to carefully eliminating sources of electrical noise in the system
P4‐655: Addressing Ad Health Disparities Through A Cultural Lens
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153187/1/alzjjalz201909021.pd
The Circumnuclear Molecular Gas in the Seyfert Galaxy NGC4945
We have mapped the central region of NGC 4945 in the transition of
CO, CO, and CO, as well as the continuum at 1.3 mm, at an
angular resolution of 5\farc \times 3\farc with the Submillimeter Array. The
relative proximity of NGC 4945 (distance of only 3.8 Mpc) permits a detailed
study of the circumnuclear molecular gas and dust in a galaxy exhibiting both
an AGN (classified as a Seyfert 2) and a circumnuclear starburst in an inclined
ring with radius 2\farcs5 (50 pc). We find that all three molecular
lines trace an inclined rotating disk with major axis aligned with that of the
starburst ring and large-scale galactic disk, and which exhibits solid-body
rotation within a radius of 5\farc (95 pc). We infer an inclination
for the nuclear disk of , somewhat smaller than the
inclination of the large-scale galactic disk of . The
continuum emission at 1.3 mm also extends beyond the starburst ring, and is
dominated by thermal emission from dust. If it traces the same dust emitting in
the far-infrared, then the bulk of this dust must be heated by star-formation
activity rather than the AGN. We discover a kinematically-decoupled component
at the center of the disk with a radius smaller than 1\farcs4 (27 pc), but
which spans approximately the same range of velocities as the surrounding disk.
This component has a higher density than its surroundings, and is a promising
candidate for the circumnuclear molecular torus invoked by AGN unification
models.Comment: 13 pages, 10 figures,accepted by Ap
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