Characterization of low-energy magnetic excitations in chromium

The low-energy excitations of Cr, i.e. the Fincher-Burke (FB) modes, have been investigated in the transversely polarized spin-density-wave phase by inelastic neutron scattering using a single-(Q+-) crystal with a propagation vector (Q+-) parallel to [0,0,1]. The constant-momentum-transfer scans show that the energy spectra consist of two components, namely dispersive FB modes and an almost energy-independent cross section. Most remarkably, we find that the spectrum of the FB modes exhibits one peak at 140 K near Q = (0,0,0.98) and two peaks near Q = (0,0,1.02), respectively. This is surprising because Cr crystallizes in a centro-symmetric bcc structure. The asymmetry of those energy spectra decreases with increasing temperature. In addition, the observed magnetic peak intensity is independent of Q suggesting a transfer of spectral-weight between the upper and lower FB modes. The energy-independent cross section is localized only between the incommensurate peaks and develops rapidly with increasing temperature.Comment: 6 pages, 8 figure

House dust mite reduction and avoidance measures for treating eczema

BACKGROUND: Eczema is an inflammatory skin disease that tends to involve skin creases, such as the folds of the elbows or knees; it is an intensely itchy skin condition, which can relapse and remit over time. As many as a third of people with eczema who have a positive test for allergy to house dust mite have reported worsening of eczema or respiratory symptoms when exposed to dust. OBJECTIVES: To assess the effects of all house dust mite reduction and avoidance measures for the treatment of eczema. SEARCH METHODS: We searched the following databases up to 14 August 2014: the Cochrane Skin Group Specialised Register, CENTRAL in The Cochrane Library (2014, Issue 8), MEDLINE (from 1946), Embase (from 1974), LILACS (from 1982), and the GREAT database. We also searched five trials registers and checked the reference lists of included and excluded studies for further references to relevant studies. We handsearched abstracts from international eczema and allergy meetings. SELECTION CRITERIA: Randomised controlled trials (RCTs) of any of the house dust mite reduction and avoidance measures for the treatment of eczema, which included participants of any age diagnosed by a clinician with eczema as defined by the World Allergy Organization. We included all non‐pharmacological and pharmacological interventions that sought to reduce or avoid exposure to house dust mite and their allergenic faeces. The comparators were any active treatment, no treatment, placebo, or standard care only. DATA COLLECTION AND ANALYSIS: Two authors independently checked the titles and abstracts identified, and there were no disagreements. We contacted authors of included studies for additional information. We assessed the risk of bias using Cochrane methodology. MAIN RESULTS: We included seven studies of 324 adults and children with eczema. Overall, the included studies had a high risk of bias. Four of the seven trials tested interventions with multiple components, and three tested a single intervention. Two of the seven trials included only children, four included children and adults, and one included only adults. Interventions to reduce or avoid exposure to house dust mite included covers for mattresses and bedding, increased or high‐quality vacuuming of carpets and mattresses, and sprays that kill house dust mites. Four studies assessed our first primary outcome of 'Clinician‐assessed eczema severity using a named scale'. Of these, one study (n = 20) did not show any significant short‐term benefit from allergen impermeable polyurethane mattress encasings and acaricide spray versus allergen permeable cotton mattress encasings and placebo acaricide spray. One study (n = 60) found a modest statistically significant benefit in the Six Area, Six Sign Atopic Dermatitis (SASSAD) scale over six months (mean difference of 4.2 (95% confidence interval 1.7 to 6.7), P = 0.008) in favour of a mite impermeable bedding system combined with benzyltannate spray and high‐filtration vacuuming versus mite permeable cotton encasings, water with a trace of alcohol spray, and a low‐filtration vacuum cleaner. The third study (n = 41) did not compare the change in severity of eczema between the two treatment groups. The fourth study (n = 86) reported no evidence of a difference between the treatment groups. With regard to the secondary outcomes 'Participant‐ or caregiver‐assessed global eczema severity score' and the 'Amount and frequency of topical treatment required', one study (n = 20) assessed these outcomes with similar results being reported for these outcomes in both groups. Four studies (n = 159) assessed 'Sensitivity to house dust mite allergen using a marker'; there was no clear evidence of a difference in sensitivity levels reported between treatments in any of the four trials. None of the seven included studies assessed our second primary outcome 'Participant‐ or caregiver‐assessed eczema‐related quality of life using a named instrument' or the secondary outcome of 'Adverse effects'. We were unable to combine any of our results because of variability in the interventions and paucity of data. AUTHORS' CONCLUSIONS: We were unable to determine clear implications to inform clinical practice from the very low‐quality evidence currently available. The modest treatment responses reported were in people with atopic eczema, specifically with sensitivity to one or more aeroallergens. Thus, their use in the eczema population as a whole is unknown. High‐quality long‐term trials of single, easy‐to‐administer house dust mite reduction or avoidance measures are worth pursuing

A method for isolating and culturing placental cells from failed early equine pregnancies

Early pregnancy loss occurs in 6–10% of equine pregnancies making it the main cause of reproductive wastage. Despite this, reasons for the losses are known in only 16% of cases. Lack of viable conceptus material has inhibited investigations of many potential genetic and pathological causes. We present a method for isolating and culturing placental cells from failed early equine pregnancies. Trophoblast cells from 18/30 (60%) failed equine pregnancies of gestational ages 14–65 days were successfully cultured in three different media, with the greatest growth achieved for cells cultured in AmnioChrome™ Plus. Genomic DNA of a suitable quality for molecular assays was also isolated from 29/30 of these cases. This method will enable future investigations determining pathologies causing EPL

New Magnetic Excitations in the Spin-Density-Wave of Chromium

Low-energy magnetic excitations of chromium have been reinvestigated with a single-Q crystal using neutron scattering technique. In the transverse spin-density-wave phase a new type of well-defined magnetic excitation is found around (0,0,1) with a weak dispersion perpendicular to the wavevector of the incommensurate structure. The magnetic excitation has an energy gap of E ~ 4 meV and at (0,0,1) exactly corresponds to the Fincher mode previously studied only along the incommensurate wavevector.Comment: 4 pages, 4 figure

Spin echo small angle neutron scattering using a continuously pumped He-3 neutron polarisation analyser

We present a new instrument for spin echo small angle neutron scattering (SESANS) developed at the Low Energy Neutron Source at Indiana University. A description of the various instrument components is given along with the performance of these components. At the heart of the instrument are a series of resistive coils to encode the neutron trajectory into the neutron polarisation. These are shown to work well over a broad range of neutron wavelengths. Neutron polarisation analysis is accomplished using a continuously operating neutron spin filter polarised by Rb spin-exchange optical pumping of 3He. We describe the performance of the analyser along with a study of the 3He polarisation stability and its implications for SESANS measurements. Scattering from silica Stöber particles is investigated and agrees with samples run on similar instruments

Pharmacokinetics of intramuscular tranexamic acid in bleeding trauma patients: a clinical trial.

BACKGROUND: Intravenous tranexamic acid (TXA) reduces bleeding deaths after injury and childbirth. It is most effective when given early. In many countries, pre-hospital care is provided by people who cannot give i.v. injections. We examined the pharmacokinetics of intramuscular TXA in bleeding trauma patients. METHODS: We conducted an open-label pharmacokinetic study in two UK hospitals. Thirty bleeding trauma patients received a loading dose of TXA 1 g i.v., as per guidelines. The second TXA dose was given as two 5 ml (0·5 g each) i.m. injections. We collected blood at intervals and monitored injection sites. We measured TXA concentrations using liquid chromatography coupled to mass spectrometry. We assessed the concentration time course using non-linear mixed-effect models with age, sex, ethnicity, body weight, type of injury, signs of shock, and glomerular filtration rate as possible covariates. RESULTS: Intramuscular TXA was well tolerated with only mild injection site reactions. A two-compartment open model with first-order absorption and elimination best described the data. For a 70-kg patient, aged 44 yr without signs of shock, the population estimates were 1.94 h-1 for i.m. absorption constant, 0.77 for i.m. bioavailability, 7.1 L h-1 for elimination clearance, 11.7 L h-1 for inter-compartmental clearance, 16.1 L volume of central compartment, and 9.4 L volume of the peripheral compartment. The time to reach therapeutic concentrations (5 or 10 mg L-1) after a single intramuscular TXA 1 g injection are 4 or 11 min, with the time above these concentrations being 10 or 5.6 h, respectively. CONCLUSIONS: In bleeding trauma patients, intramuscular TXA is well tolerated and rapidly absorbed. CLINICAL TRIAL REGISTRATION: 2019-000898-23 (EudraCT); NCT03875937 (ClinicalTrials.gov)

On critical behavior of phase transitions in certain antiferromagnets with complicated ordering

Within the four-loop \ve expansion, we study the critical behavior of certain antiferromagnets with complicated ordering. We show that an anisotropic stable fixed point governs the phase transitions with new critical exponents. This is supported by the estimate of critical dimensionality $N_c^C=1.445(20)$ obtained from six loops via the exact relation $N_c^C={1/2} N_c^R$ established for the real and complex hypercubic models.Comment: Published versio

An asymptotic form of the reciprocity theorem with applications in x-ray scattering

The emission of electromagnetic waves from a source within or near a non-trivial medium (with or without boundaries, crystalline or amorphous, with inhomogeneities, absorption and so on) is sometimes studied using the reciprocity principle. This is a variation of the method of Green's functions. If one is only interested in the asymptotic radiation fields the generality of these methods may actually be a shortcoming: obtaining expressions valid for the uninteresting near fields is not just a wasted effort but may be prohibitively difficult. In this work we obtain a modified form the reciprocity principle which gives the asymptotic radiation field directly. The method may be used to obtain the radiation from a prescribed source, and also to study scattering problems. To illustrate the power of the method we study a few pedagogical examples and then, as a more challenging application we tackle two related problems. We calculate the specular reflection of x rays by a rough surface and by a smoothly graded surface taking polarization effects into account. In conventional treatments of reflection x rays are treated as scalar waves, polarization effects are neglected. This is a good approximation at grazing incidence but becomes increasingly questionable for soft x rays and UV at higher incidence angles. PACs: 61.10.Dp, 61.10.Kw, 03.50.DeComment: 19 pages, 4 figure

Overview of progress on the improvement projects for the LANSCE accelerator and target facilities

Three projects have been initiated since 1994 to improve the performance of the accelerator and target facilities for the Los Alamos Neutron Science Center (LANSCE). The LANSCE Reliability Improvement Project (LRIP) was separated into two phases. Phase 1, completed in 1995, targeted near-term improvements to beam reliability and availability that could be completed in one-year`s time. Phase 2, now underway and scheduled for completion in May 1998, consists of two projects: (a) implementation of direct H-injection for the Proton Storage Ring (PSR) and (b) an upgrade of the target/moderator system for the short pulse spallation neutron (SPSS) source. The latter will reduce the target change-out time from about 10 months to about three weeks. The third project, the SPSS Enhancement Project, is aimed at increasing the PSR output beam current to 200 {micro}A at 30 Hz and providing up to seven new neutron scattering instruments