Development and operation of the defence COVID-19 lab as a SARS-CoV-2 diagnostic screening capability for UK military personnel.

BACKGROUND: In the face of the COVID-19 pandemic, the Defence Science and Technology Laboratory (Dstl) and Defence Pathology combined to form the Defence Clinical Lab (DCL), an accredited (ISO/IEC 17025:2017) high-throughput SARS-CoV-2 PCR screening capability for military personnel. LABORATORY STRUCTURE AND RESOURCE: The DCL was modular in organisation, with laboratory modules and supporting functions combining to provide the accredited SARS-CoV-2 (envelope (E)-gene) PCR assay. The DCL was resourced by Dstl scientists and military clinicians and biomedical scientists. LABORATORY RESULTS: Over 12 months of operation, the DCL was open on 289 days and tested over 72 000 samples. Six hundred military SARS-CoV-2-positive results were reported with a median E-gene quantitation cycle (Cq) value of 30.44. The lowest Cq value for a positive result observed was 11.20. Only 64 samples (0.09%) were voided due to assay inhibition after processing started. CONCLUSIONS: Through a sustained effort and despite various operational issues, the collaboration between Dstl scientific expertise and Defence Pathology clinical expertise provided the UK military with an accredited high-throughput SARS-CoV-2 PCR test capability at the height of the COVID-19 pandemic. The DCL helped facilitate military training and operational deployments contributing to the maintenance of UK military capability. In offering a bespoke capability, including features such as testing samples in unit batches and oversight by military consultant microbiologists, the DCL provided additional benefits to the UK Ministry of Defence that were potentially not available from other SARS-CoV-2 PCR laboratories. The links between Dstl and Defence Pathology have also been strengthened, benefitting future research activities and operational responses.

Evidence of soft dipole resonance in

The first conclusive evidence of a dipole resonance in ^{11}Li having isoscalar character observed from inelastic scattering with a novel solid deuteron target is reported. The experiment was performed at the newly commissioned IRIS facility at TRIUMF. The results show a resonance peak at an excitation energy of 1.03±0.03 MeV with a width of 0.51±0.11 MeV (FWHM). The angular distribution is consistent with a dipole excitation in the distorted-wave Born approximation framework. The observed resonance energy together with shell model calculations show the first signature that the monopole tensor interaction is important in ^{11}Li. The first ab initio calculations in the coupled cluster framework are also presented.

Low-temperature triple-alpha rate in a full three-body nuclear model.

A new three-body method is used to compute the rate of the triple-alpha capture reaction, which is the primary source of 12C in stars. In this Letter, we combine the Faddeev hyperspherical harmonics and the R-matrix method to obtain a full solution to the three-body α+α+α continuum. Particular attention is paid to the long-range effects caused by the pairwise Coulomb interactions. The new rate agrees with the Nuclear Astrophysics Compilation of Reaction rates for temperatures greater than 0.07 GK, but a large enhancement at lower temperature is found (≈10(12) at 0.02 GK). Our results are compared to previous calculations where additional approximations were made. We show that the new rate does not significantly change the evolution of stars around one solar mass. In particular, such stars still undergo a red-giant phase consistent with observations, and no significant differences are found in the final white dwarfs.

Measurements of the T(t,2n)4He neutron spectrum at low reactant energies from inertial confinement implosions.

Measurements of the neutron spectrum from the T(t,2n)4He (tt) reaction have been conducted using inertial confinement fusion implosions at the OMEGA laser facility. In these experiments, deuterium-tritium (DT) gas-filled capsules were imploded to study the tt reaction in thermonuclear plasmas at low reactant center-of-mass (c.m.) energies. In contrast to accelerator experiments at higher c.m. energies (above 100 keV), these results indicate a negligible n + 5He reaction channel at a c.m. energy of 23 keV.

Conjugation of Y. pestis F1-antigen to gold nanoparticles improves immunogenicity.

The efficacy of 15 nm gold nanoparticles (AuNP) coated with Yersinia pestis F1-antigen, as an immunogen in mice, has been assessed. The nanoparticles were decorated with F1-antigen using N-hydroxysuccinimide and N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride coupling chemistry. Mice given AuNP-F1 in alhydrogel generated the greatest IgG antibody response to F1-antigen when compared with mice given AuNP-F1 in PBS or given unconjugated F1-antigen in PBS or alhydrogel. Compared with unconjugated F1-antigen, the IgG2a response was enhanced in mice dosed with AuNP-F1 in PBS (p<0.05) but not in mice immunised with AuNP-F1 in alhydrogel. All treatment groups developed a memory response to F1-antigen, the polarity of which was inflenced by formulation in alhydrogel. The sera raised against F1-antigen coupled to AuNPs was able to competitively bind to rF1-antigen, displacing protective macaque sera.

Coupled-channel calculation of nonelastic cross sections using a density-functional structure model.

A microscopic calculation of reaction cross sections for nucleon-nucleus scattering was performed by coupling the elastic channel to all particle-hole excitations in the target and one-nucleon pickup channels. The particle-hole states may be regarded as doorway states through which the flux flows to more complicated configurations, and subsequently to long-lived compound nucleus resonances. Target excitations for (40,48)Ca, 58Ni, 90Zr, and 144Sm were described in a random-phase framework using a Skyrme functional. Reaction cross sections obtained agreed very well with experimental data and predictions of a fitted optical potential. Couplings between inelastic states were found to be negligible, while the pickup channels contribute significantly. For the first time observed absorptions are completely accounted for by explicit channel coupling, for incident energies between 10 and 40 MeV.

Measurement of the two-halo neutron transfer reaction (1)H((11)Li, (9)Li)(3)H at 3A MeV.

The p((11)Li, (9)Li)t reaction has been studied for the first time at an incident energy of 3A MeV at the new ISAC-2 facility at TRIUMF. An active target detector MAYA, built at GANIL, was used for the measurement. The differential cross sections have been determined for transitions to the (9)Li ground and first excited states in a wide range of scattering angles. Multistep transfer calculations using different (11)Li model wave functions show that wave functions with strong correlations between the halo neutrons are the most successful in reproducing the observation.

15C-15F Charge symmetry and the 14C(n,gamma)15C reaction puzzle.

The low-energy reaction 14C(n,gamma)15C provides a rare opportunity to test indirect methods for the determination of neutron capture cross sections by radioactive isotopes versus direct measurements. It is also important for various astrophysical scenarios. Currently, puzzling disagreements exist between the 14C(n,gamma)15C cross sections measured directly, determined indirectly, and calculated theoretically. To solve this puzzle, we offer a strong test based on a novel idea that the amplitudes for the virtual 15C-->14C + n and the real 15F -->14O + p decays are related. Our study of this relation, performed in a microscopic model, shows that existing direct and some indirect measurements strongly contradict charge symmetry in the 15C and 15F mirror pair. This brings into question the experimental determinations of the astrophysically important (n,gamma) cross sections for short-lived radioactive targets.

Two-proton widths of 12O, 16Ne, and three-body mechanism of Thomas-Ehrman shift.

Two-proton decays of 12O and 16Ne ground states are studied in a three-body model. We have found that the two-proton widths for the states should be much less than the existing experimental values (about 10 times for 12O and about 100 times for 16Ne). We also have found that the structure of these states differs significantly from the mirror isobaric analog states (IAS): breaking of isobaric symmetry is at the level of tens of percents. Together with a corresponding decrease of the Coulomb energy, this effect can be considered as a three-body mechanism of the Thomas-Ehrman shift.

A mechanism for combinatorial regulation of electrical activity: Potassium channel subunits capable of functioning as Src homology 3-dependent adaptors.

It is an open question how ion channel subunits that lack protein-protein binding motifs become targeted and covalently modified by cellular signaling enzymes. Here, we show that Src-family protein tyrosine kinases (PTKs) bind to heteromultimeric Shaker-family voltage-gated potassium (Kv) channels by interactions between the Src homology 3 (SH3) domain and the proline-rich SH3 domain ligand sequence in the Shaker-family subunit Kv1.5. Once bound to Kv1.5, Src-family PTKs phosphorylate adjacent subunits in the Kv channel heteromultimer that lack proline-rich SH3 domain ligand sequences. This SH3-dependent tyrosine phosphorylation contributes to significant suppression of voltage-evoked currents flowing through the heteromultimeric channel. These results demonstrate that Kv1.5 subunits function as SH3-dependent adaptor proteins that marshal Src-family kinases to heteromultimeric potassium channel signaling complexes, and thereby confer functional sensitivity upon coassembled channel subunits that are themselves not bound directly to Src-family kinases by allowing their phosphorylation. This is a mechanism for information transfer between subunits in heteromultimeric ion channels that is likely to underlie the generation of combinatorial signaling diversity in the control of cellular electrical excitability.

Gastric motility and emptying in normal and post-vagotomy subjects.

The effects of proximal gastric vagotomy (PGV) and vagotomy with pyloroplasty (V and P) on gastric motility were studied using a solid meal labelled with a radiopharmaceutical agent. In having on-line computer facilities it was possible not only to record the rate of emptying but also to analyse the relative roles of the fundus and the antrum within the overall framework of gastric emptying. In normal subjects the fundus filled and then emptied in an almost linear pattern. The antrum, however, did not completely fill until well after the meal was eaten and thereafter appeared to maintain a constant volume during the study. The redistribution of contents between fundus and antrum was reflected in the total stomach emptying curve as a delay, or lag phase before gastric emptying commenced. After both types of vagotomy fundic filling was delayed, representing a slower eating time, which was presumably due to early satiety. Antral filling and volume was disturbed only after V and P, which was also reflected by a loss of the lag phase seen on the total stomach curve. PGV retained antral function but there was significant delay in the redistribution of contents between fundus and antrum, though this did not have clinical significance. The rate of emptying was unaffected by either operation. It was concluded PGV did maintain antral function and a more normal pattern of emptying compared with V and P. After V and P the changes in antral function were considerable and these changes are probably associated with some of the complications resulting from this operation.

The initial phase of gastric emptying before and after vagotomy and pyloroplasty.

The initial phase of gastric emptying of solid food was monitored with the use of a gamma camera and on-line computer facilities. In normal subjects a consistent pattern was seen comprising an early delay in the onset of emptying ("plateau"), followed by an exponential decay curve. After vagotomy the plateau was lost, and the exponential pattern of emptying commenced once the stomach was full. There was no evidence of sudden "dumping" of contents from the stomach. The overall rates of emptying as measured by the half emptying time (T 1/2) were the same in normal and postvagotomy subjects.