Incommensurate antiferromagnetic fluctuations in single-crystalline LiFeAs studied by inelastic neutron scattering

We present an inelastic neutron scattering study on single-crystalline LiFeAs devoted to the characterization of the incommensurate antiferromagnetic fluctuations at $\mathbf{Q}=(0.5\pm\delta, 0.5\mp\delta, q_l)$. Time-of-flight measurements show the presence of these magnetic fluctuations up to an energy transfer of 60 meV, while polarized neutrons in combination with longitudinal polarization analysis on a triple-axis spectrometer prove the pure magnetic origin of this signal. The normalization of the magnetic scattering to an absolute scale yields that magnetic fluctuations in LiFeAs are by a factor eight weaker than the resonance signal in nearly optimally Co-doped BaFe$_2$As$_2$, although a factor two is recovered due to the split peaks owing to the incommensurability. The longitudinal polarization analysis indicates weak spin space anisotropy with slightly stronger out-of-plane component between 6 and 12 meV. Furthermore, our data suggest a fine structure of the magnetic signal most likely arising from superposing nesting vectors.Comment: 9 pages, 8 figure

PP23 Evaluation of pre-hospital use of a valsalva assist device (VAD) in the Emergency treatment of supraventricular tachycardia (SVT) [EVADE]. A randomised controlled feasibility trial.

Background Supraventricular tachycardia (SVT) is a common heart rhythm disorder. The Valsalva Manoeuvre (VM) is a safe, internationally recommended, initial treatment, but has a low success rate in normal practice. Recent studies have shown much better cardioversion rates, approaching 50%, can be achieved using a postural modification (the modified VM) and a manometer controlled 40 mmHg strain. Successful cardioversion could avoid hospital conveyance and unpleasant treatments, such as adenosine. Routine use of a manometer is not practical out of hospital. Blowing on an empty syringe has been suggested as an alternative but is unreliable in providing correct and consistent pressures. A Valsalva Assist Device (VAD), designed to provide a 40 mmHg strain resistance has been developed. It is small, portable, can be packaged with instructions for the modified VM and if successful, may be left with the patient. Methods We conducted a pragmatic, randomised controlled feasibility trial, comparing VAD versus standard practice delivered VMs. All other aspects of care were according to SWASFT guidelines. Participants were followed up to ask their views on trial procedures. Interim results (month 5 of 6) 23 volunteer Station Leads recruited 22 Study Clinicians from 27 ambulance stations. 29 patients were enrolled over 5 months, 19 in the last 2 months (the first 3 months included steady recruitment and setup). The later enrolment rate extrapolates to a presentation rate of approximately 220 eligible patients to SWASFT each year. Complete data sets were available in 100% of participants. When followed up, participants reported verbal consent to be widely acceptable, although SVT symptoms were substantially distracting for many during this process. Conclusion Our experience of recruitment and data collection suggest a definitive trial, using similar methodology, is possible, but the low occurrence rate may challenge feasibility. Consent taking methods may require refinement for a larger trial

The measurement of response shift in patients with advanced prostate cancer and their partners

BACKGROUND: There is increasing evidence to support the phenomenon of response shift (RS) in quality of life (QoL) studies, with many current QoL measures failing to allow for this. If significant response shift occurs amongst prostate cancer patients, it will be necessary to allow for this in the design of future clinical research and to reassess the conclusions of previous studies that have not allowed for this source of bias. This study therefore aimed to assess the presence of RS and psychosocial morbidity in patients with advanced prostate cancer and their partners. METHODS: 55 consecutive advanced prostate cancer patients and their partners completed the Prostate Cancer Patient & Partner questionnaire (PPP), shortly after diagnosis and again at 3 months and 6 months. At the follow-up visits, both patients and partners also completed a then-test in order to assess RS. RESULTS: Partners consistently showed greater psychological morbidity than patients in relation to the prostate cancer. This was most marked on the General Cancer Distress (GCD) subscale (p < 0.001, paired t-test), and regarding worries about treatment (p = 0.01). Significant RS was identified in partners and patients by the use of the then-test technique, particularly on the GCD subscale, the concerns about treatment and the concerns about urinary symptoms items. CONCLUSION: These results suggest the presence of RS in patients with advanced prostate cancer and their partners, with higher levels of psychosocial morbidity noted amongst partners. This is the first study to identify RS in partners and calls into question the interpretation of all studies assessing changes in QoL that fail to allow for this phenomenon

Two-dimensional ferromagnetic spin-orbital excitations in honeycomb VI3

VI$_{3}$ is a ferromagnet with planar honeycomb sheets of bonded V$^{3+}$ ions held together by van der Waals forces. We apply neutron spectroscopy to measure the two dimensional ($J/J_{c} \approx 17$) magnetic excitations in the ferromagnetic phase, finding two energetically gapped ($\Delta \approx k_{B} T_{c} \approx$ 55 K) and dispersive excitations. We apply a multi-level spin wave formalism to describe the spectra in terms of two coexisting domains hosting differing V$^{3+}$ orbital ground states built from contrasting distorted octahedral environments. This analysis fits a common nearest neighbor in-plane exchange coupling ($J$=-8.6 $\pm$ 0.3 meV) between V$^{3+}$ sites. The distorted local crystalline electric field combined with spin-orbit coupling provides the needed magnetic anisotropy for spatially long-ranged two-dimensional ferromagnetism in VI$_{3}$.Comment: (main text - 7 pages, 4 figures; supplementary information - 13 pages, 9 figures, to be published in Phys. Rev. B

Investigation of the dynamics of 1-octene adsorption at 293 K in a ZSM-5 catalyst by inelastic and quasielastic neutron scattering

The properties of 1-octene adsorbed in zeolite ZSM-5 at 293 K are studied by means of inelastic and quasielastic neutron scattering (INS and QENS) in order to investigate interactions relevant to the zeolite solid acid catalysis of fluidised catalytic cracking reactions. The INS spectrum is compared to that recorded for the solid alkene and reveals significant changes of bonding on adsorption at ambient temperatures; the changes are attributed to the oligomerization of the adsorbed 1-octene to form a medium chain n-alkane or n-alkane cation. QENS analysis shows that these oligomers are immobilised within the zeolite pore structure but a temperature-dependant fraction is able to rotate around their long axis within the pore channels

Magnetic Excitations of Undoped Iron Oxypnictides

We study the magnetic excitations of undoped iron oxypnictides using a three-dimensional Heisenberg model with single-ion anisotropy. Analytic forms of the spin wave dispersion, velocities, and structure factor are given. Aside from quantitative comparisons which can be made to inelastic neutron scattering experiments, we also give qualitative criteria which can distinguish various regimes of coupling strength. The magnetization reduction due to quantum zero point fluctuations shows clear dependence on the c-axis coupling.Comment: 4 pages, 5 figures, to appear in Frontiers of Physics in China: a special issue on Iron-based superconductor

PAin SoluTions In the Emergency Setting (PASTIES)--patient controlled analgesia versus routine care in emergency department patients with non-traumatic abdominal pain: randomised trial

© Smith et al 2015. OBJECTIVE: To determine whether patient controlled analgesia (PCA) is better than routine care in providing effective analgesia for patients presenting to emergency departments with moderate to severe non-traumatic abdominal pain.DESIGN: Pragmatic, multicentre, parallel group, randomised controlled trialSETTING: Five English hospitals.PARTICIPANTS: 200 adults (66% (n=130) female), aged 18 to 75 years, who presented to the emergency department requiring intravenous opioid analgesia for the treatment of moderate to severe non-traumatic abdominal pain and were expected to be admitted to hospital for at least 12 hours.INTERVENTIONS: Patient controlled analgesia or nurse titrated analgesia (treatment as usual).MAIN OUTCOME MEASURES: The primary outcome was total pain experienced over the 12 hour study period, derived by standardised area under the curve (scaled from 0 to 100) of each participant's hourly pain scores, captured using a visual analogue scale. Pre-specified secondary outcomes included total morphine use, percentage of study period in moderate or severe pain, percentage of study period asleep, length of hospital stay, and satisfaction with pain management.RESULTS: 196 participants were included in the primary analyses (99 allocated to PCA and 97 to treatment as usual). Mean total pain experienced was 35.3 (SD 25.8) in the PCA group compared with 47.3 (24.7) in the treatment as usual group. The adjusted between group difference was 6.3 (95% confidence interval 0.7 to 11.9). Participants in the PCA group received significantly more morphine (mean 36.1 (SD 22.4) v 23.6 (13.1) mg; mean difference 12.3 (95% confidence interval 7.2 to 17.4) mg), spent less of the study period in moderate or severe pain (32.6% v 46.9%; mean difference 14.5% (5.6% to 23.5%)), and were more likely to be perfectly or very satisfied with the management of their pain (83% (73/88) v 66% (57/87); adjusted odds ratio 2.56 (1.25 to 5.23)) in comparison with participants in the treatment as usual group.CONCLUSIONS: Significant reductions in pain can be achieved by PCA compared with treatment as usual in patients presenting to the emergency department with non-traumatic abdominal pain. Trial registration European Clinical Trials Database EudraCT2011-000194-31; Current Controlled Trials ISRCTN25343280