A versatile laser-based apparatus for time-resolved ARPES with micro-scale spatial resolution

We present the development of a versatile apparatus for 6.2 eV laser-based time and angle-resolved photoemission spectroscopy with micrometer spatial resolution (time-resolved μ-ARPES). With a combination of tunable spatial resolution down to ∼11 μm, high energy resolution (∼11 meV), near-transform-limited temporal resolution (∼280 fs), and tunable 1.55 eV pump fluence up to 3 mJ/cm2, this time-resolved μ-ARPES system enables the measurement of ultrafast electron dynamics in exfoliated and inhomogeneous materials. We demonstrate the performance of our system by correlating the spectral broadening of the topological surface state of Bi2Se3 with the spatial dimension of the probe pulse, as well as resolving the spatial inhomogeneity contribution to the observed spectral broadening. Finally, after in situ exfoliation, we performed time-resolved μ-ARPES on a ∼30 μm flake of transition metal dichalcogenide WTe2, thus demonstrating the ability to access ultrafast electron dynamics with momentum resolution on micro-exfoliated materials.

Laparoscopic versus open appendicectomy performed by adult general surgeons in pre-teenage years children: a single-centre experience

INTRODUCTION

The utilisation of laparoscopic appendicectomy (LA) in children remains contentious despite the well-recognised advantages of laparoscopic surgery. The purpose of this study was to compare intraoperative and postoperative outcomes in LA and open appendicectomy (OA) when performed by adult general surgeons outside specialist paediatric practice in younger children.

METHODS

A retrospective review of all patients under the age of 13 who underwent LA for suspected appendicitis over a two-year period was conducted. These were case-matched with an equivalent number of patients who underwent OA during the same period. Intraoperative and postoperative outcomes were compared.

RESULTS

Fifty-one patients underwent LA during the study period. Patient demographics were statistically equivalent with the OA cohort. A statistically significant longer median operating time (58 vs 49min) was noted in the LA group, but intraoperative outcomes were otherwise comparable. LA, when compared with OA, was associated with a significant improvement in postoperative length of stay (2 vs 3 days, p < 0.001), postoperative complication rate (0% vs 6%, p = 0.01), negative appendicectomy rate (3.9% vs 17.6%, p < 0.001) and 30-day readmission rate (0% vs 5.9%, p = 0.03). No patients in the LA group required conversion to open surgery.

CONCLUSION

LA can be safely delivered by adult general surgeons to younger paediatric populations outside the setting of paediatric specialist practice, with statistically significant improvements in postoperative outcomes noted when compared with OA. These findings are of importance in the current healthcare context where adult general surgeons continue to perform the majority of paediatric appendicectomies.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Finite-Size Effect in Phonon-Induced Elliott-Yafet Spin Relaxation in Al

The Elliott-Yafet theory of spin relaxation in nonmagnetic metals predicts proportionality between spin and momentum relaxation times for scattering centers such as phonons. Here, we test this theory in Al nanowires over a very large thickness range (8.5-300 nm), finding that the Elliott-Yafet proportionality "constant" for phonon scattering in fact exhibits a large, unanticipated finite-size effect. Supported by analytical and numerical modeling, we explain this via strong phonon-induced spin relaxation at surfaces and interfaces, driven in particular by enhanced spin-orbit coupling.

Electron beam evaporation of superconductor-ferromagnet heterostructures

We report on the electronic and magnetic properties of superconductor-ferromagnet heterostructures fabricated by electron beam evaporation on to unheated thermally oxidised Si substrates. Polycrystalline Nb thin films (5 to 50 nm thick) were shown to possess reliably high superconducting critical temperatures (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T_{c}$$\end{document}Tc), which correlate well with the residual resistivity ratio (RRR) of the film. These properties improved during ex-situ annealing, resulting in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\Delta }T_{c}$$\end{document}ΔTc and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\Delta }$$\end{document}ΔRRR increases of up 2.2 K (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim$$\end{document}∼ 40% of the pre-annealed \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T_{c}$$\end{document}Tc) and 0.8 (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim$$\end{document}∼ 60% of the pre-annealed RRR) respectively. Nb/Pt/Co/Pt heterostructures showed substantial perpendicular anisotropy in the ultrathin limit (≤ 2.5 nm), even in the extreme limit of Pt(0.8 nm)/Co(1 nm)/Pt(0.6 nm). These results point to the use of electron beam evaporation as route to line-of-sight deposited, low-thickness, high quality Nb-based superspintronic multilayers.

Identification of RHD allelic variants discovered by atypical typing results on the NEO/Echo platforms

Some individuals are at risk of anti-D alloimmunization if they inherit D antigens that are qualitatively and/or quantitatively different than wild-type D. We hypothesized that patients who showed serologically inconsistent, weak, or historically discordant D typing results by microplate direct agglutination (MDA) on NEO or Echo (Immucor, Norcross, GA) might be at risk of carrying RHD allelic variants. The present study was designed to evaluate patients with RHD allelic variants if they presented with weakly reactive D typing results on the NEO or Echo. Patients were selected for RHD genotyping if their specimens showed weak reactivity with either series 4 or series 5 anti-D typing reagent, if the strength of reactivity was ≤1+ on the NEO or Echo, or if historical or current D typing results were discordant with current results. Patients selected for RHD genotyping were also tested by saline tube testing using the same anti-D series 4 and 5 reagents. Genotyping was performed by the Immucor genotyping laboratory in Warren, NJ. Of 80 patients whose samples met study inclusion, 52 (65.0%) were found to have RHD allelic variants. Sixteen patients (20.0%) expressed possible Ceppellini effect reactivity. Most importantly, 51.25 percent of the patients who presented with weakly reactive D typing results by MDA testing on the NEO (≤1+) or Echo (≤1+) had RHD allelic variants that were associated with the potential for anti-D alloimmunization. Laboratories that use MDA testing on the Neo or Echo for D typing should consider that female patients of childbearing age might be at risk of anti-D alloimmunization if they are classified as D+ based on weakly reactive D typing results. Some individuals are at risk of anti-D alloimmunization if they inherit D antigens that are qualitatively and/or quantitatively different than wild-type D. We hypothesized that patients who showed serologically inconsistent, weak, or historically discordant D typing results by microplate direct agglutination (MDA) on NEO or Echo (Immucor, Norcross, GA) might be at risk of carrying RHD allelic variants. The present study was designed to evaluate patients with RHD allelic variants if they presented with weakly reactive D typing results on the NEO or Echo. Patients were selected for RHD genotyping if their specimens showed weak reactivity with either series 4 or series 5 anti-D typing reagent, if the strength of reactivity was ≤1+ on the NEO or Echo, or if historical or current D typing results were discordant with current results. Patients selected for RHD genotyping were also tested by saline tube testing using the same anti-D series 4 and 5 reagents. Genotyping was performed by the Immucor genotyping laboratory in Warren, NJ. Of 80 patients whose samples met study inclusion, 52 (65.0%) were found to have RHD allelic variants. Sixteen patients (20.0%) expressed possible Ceppellini effect reactivity. Most importantly, 51.25 percent of the patients who presented with weakly reactive D typing results by MDA testing on the NEO (≤1+) or Echo (≤1+) had RHD allelic variants that were associated with the potential for anti-D alloimmunization. Laboratories that use MDA testing on the Neo or Echo for D typing should consider that female patients of childbearing age might be at risk of anti-D alloimmunization if they are classified as D+ based on weakly reactive D typing results.

Theory of Kondo suppression of spin polarization in nonlocal spin valves

We theoretically analyze contributions from the Kondo effect to the spin polarization and spin diffusion length in all-metal nonlocal spin valves. Interdiffusion of ferromagnetic atoms into the normal metal layer creates a region in which Kondo physics plays a significant role, giving discrepancies between experiment and existing theory. We start from a simple model and construct a modified spin drift-diffusion equation which clearly demonstrates how the Kondo physics not only suppresses the electrical conductivity but even more strongly reduces the spin diffusion length. We also present an explicit expression for the suppression of spin polarization due to Kondo physics in an illustrative regime. We compare this theory to previous experimental data to extract an estimate of the Elliot-Yafet probability for Kondo spin flip scattering of 0.7 ± 0.4, in good agreement with the value of 2/3 derived in the original theory of Kondo.

Early commencement of physical therapy in the acute phase following elective lower limb arthroplasty produces favorable outcomes: a systematic review and meta-analysis examining allied health service models

BACKGROUND

Temporal and dose-response relationships between allied health (AH) and recovery in the acute phase following lower limb (LL) arthroplasty are unclear. This systematic review investigates whether early commencement, additional therapy and/or weekend AH affects length of stay (LOS) and patient outcomes in the acute phase following LL arthroplasty.

METHODS

Electronic databases were searched in February 2015. Studies were included if they evaluated any of the following aspects of AH for adults following LL arthroplasty in the acute phase: Early compared to later therapy commencement; Additional therapy; or a 6- or 7-day service compared to a lesser service.

RESULTS

Twenty-four studies met the inclusion criteria, of which 19 investigated effects of physical therapy (PT) alone. Earlier PT reduced LOS (WMD = -1.23 days; 95% CI, -2.16 to -0.30) and resulted in higher probability of discharge directly home (relative risk = 1.45; 95% CI, 1.26-1.67). Addition of weekend PT reduced LOS (WMD = -1.04 days; 95% CI, -1.66 to -0.41) and improved function (SMD = 0.37; 95% CI, 0.02-0.73). Increasing PT from once to twice daily did not affect LOS (WMD = -0.35 days; 95% CI, -0.96-0.26) or function (SMD = 0.31; 95% CI, -0.06-0.71).

DISCUSSION

Early PT commencement and a weekend service may produce favorable outcomes following LL arthroplasty when baseline LOS is 4 days or more. Redistributing PT resources to commence as early as day of surgery regardless of weekday may accelerate postoperative recovery. Current, high quality research is needed to confirm these findings.

Kondo physics in non-local metallic spin transport devices

The non-local spin-valve is pivotal in spintronics, enabling separation of charge and spin currents, disruptive potential applications and the study of pressing problems in the physics of spin injection and relaxation. Primary among these problems is the perplexing non-monotonicity in the temperature-dependent spin accumulation in non-local ferromagnetic/non-magnetic metal structures, where the spin signal decreases at low temperatures. Here we show that this effect is strongly correlated with the ability of the ferromagnetic to form dilute local magnetic moments in the NM. This we achieve by studying a significantly expanded range of ferromagnetic/non-magnetic combinations. We argue that local moments, formed by ferromagnetic/non-magnetic interdiffusion, suppress the injected spin polarization and diffusion length via a manifestation of the Kondo effect, thus explaining all observations. We further show that this suppression can be completely quenched, even at interfaces that are highly susceptible to the effect, by insertion of a thin non-moment-supporting interlayer.

Development of the nano-dust analyzer (NDA) for detection and compositional analysis of nanometer-size dust particles originating in the inner heliosphere

A linear time-of-flight mass spectrometer is developed for the detection and chemical analysis of nanometer-sized particles originating near the Sun. Nano-dust particles are thought to be produced by mutual collisions between interplanetary dust particles slowly spiraling toward the Sun and are accelerated outward to high velocities by interaction with the solar wind plasma. The WAVES instruments on the two STEREO spacecraft reported the detection, strong temporal variation, and potentially high flux of these particles. Here we report on the optimization and the results from the detailed characterization of the instrument's performance using submicrometer sized dust particles accelerated to 8-60 km/s. The Nano Dust Analyzer (NDA) concept is derived from previously developed detectors. It has a 200 cm(2) effective target area and a mass resolution of approximately m/Δm = 50. The NDA instrument is designed to reliably detect and analyze nanometer-sized dust particles while being pointed close to the Sun's direction, from where they are expected to arrive. Measurements by such an instrument will determine the size-dependent flux of the nano-dust particles and its variations, it will characterize the composition of the nano-dust and, ultimately, it may determine their source. The flight version of the NDA instrument is estimated to be <5 kg and requires <10 W for operation.

Domain wall interactions at a cross-shaped vertex

The interaction of two domain walls (DWs) at a cross-shaped vertex fabricated from two ferromagnetic nanowires has been experimentally investigated. Both magnetostatically repulsive and attractive interactions have been probed. It is found that in the repulsive case, a passing DW may directly induce the depinning of another that is already pinned at a vertex. This effect can be qualitatively described by considering only simple, magnetostatic-charge-based arguments. In the attractive case, however, asymmetric pinning is found, with complete suppression of depinning possible. This observed effect is contrary to simple charge-based arguments and highlights the need for full micromagnetic characterization of the DW interactions in more complex systems.

Germline BRCA1 mutations increase prostate cancer risk

BACKGROUND

Prostate cancer (PrCa) is one of the most common cancers affecting men but its aetiology is poorly understood. Family history of PrCa, particularly at a young age, is a strong risk factor. There have been previous reports of increased PrCa risk in male BRCA1 mutation carriers in female breast cancer families, but there is a controversy as to whether this risk is substantiated. We sought to evaluate the role of germline BRCA1 mutations in PrCa predisposition by performing a candidate gene study in a large UK population sample set.

METHODS

We screened 913 cases aged 36–86 years for germline BRCA1 mutation, with the study enriched for cases with an early age of onset. We analysed the entire coding region of the BRCA1 gene using Sanger sequencing. Multiplex ligation-dependent probe amplification was also used to assess the frequency of large rearrangements in 460 cases.

RESULTS

We identified 4 deleterious mutations and 45 unclassified variants (UV). The frequency of deleterious BRCA1 mutation in this study is 0.45%; three of the mutation carriers were affected at age 65 years and one developed PrCa at 69 years. Using previously estimated population carrier frequencies, deleterious BRCA1 mutations confer a relative risk of PrCa of ~3.75-fold, (95% confidence interval 1.02–9.6) translating to a 8.6% cumulative risk by age 65.

CONCLUSION

This study shows evidence for an increased risk of PrCa in men who harbour germline mutations in BRCA1. This could have a significant impact on possible screening strategies and targeted treatments.

Dynamic oscillations of coupled domain walls

In domain wall (DW) excitation experiments, nonlinearity (NL) intrinsic to the DW dynamics is often hard to distinguish from perturbation due to the confining potential or DW distortion. Here we numerically investigate the dynamic oscillations of magnetostatically coupled DWs: a system well understood in the quasistatic limit. NL is observed, even for a harmonic potential, due to the intrinsic DW motion. This behavior is principally dependent on terms normally associated with the DW canonical momentum and is in contrast with a NL restoring potential. This NL is not observable in quasistatic measurements, relatively insensitive to the confining potential, and may be tuned by the nanowire parameters. The shown NLs are present in any DW restoring potential and must be accounted for when probing DW potential landscapes.

Dynamic propagation and nucleation in domain wall nanowire devices

The dynamic injection and propagation of domain walls (DWs) in technologically relevant geometries have been investigated. On short (~10 ns) timescales nucleation of a DW by a localized Oersted field is found to be well described using a Néel-Brown reversal mode. Using locally injected DWs, we test the propagation of DWs over long distances (~100 µm) in close proximity nanowires and beyond the Walker breakdown limit. In nanowires that act as true conduits to a DW, data can be successfully propagated without loss or inter-wire cross-talk. This is in contrast to poorly characterized systems where the DW is found to propagate asynchronously above the critical breakdown field.

Identification of a novel prostate cancer susceptibility variant in the KLK3 gene transcript

Genome-wide association studies (GWAS) have identified more than 30 prostate cancer (PrCa) susceptibility loci. One of these (rs2735839) is located close to a plausible candidate susceptibility gene, KLK3, which encodes prostate-specific antigen (PSA). PSA is widely used as a biomarker for PrCa detection and disease monitoring. To refine the association between PrCa and variants in this region, we used genotyping data from a two-stage GWAS using samples from the UK and Australia, and the Cancer Genetic Markers of Susceptibility (CGEMS) study. Genotypes were imputed for 197 and 312 single nucleotide polymorphisms (SNPs) from HapMap2 and the 1000 Genome Project, respectively. The most significant association with PrCa was with a previously unidentified SNP, rs17632542 (combined P = 3.9 × 10⁻²²). This association was confirmed by direct genotyping in three stages of the UK/Australian GWAS, involving 10,405 cases and 10,681 controls (combined P = 1.9 × 10⁻³⁴). rs17632542 is also shown to be associated with PSA levels and it is a non-synonymous coding SNP (Ile179Thr) in KLK3. Using molecular dynamic simulation, we showed evidence that this variant has the potential to introduce alterations in the protein or affect RNA splicing. We propose that rs17632542 may directly influence PrCa risk.

Characteristics of patients referred by police to a psychiatric hospital

To identify any differences between patients referred by police compared with patients referred from other sources, to a psychiatric hospital in Australia, a retrospective audit of 200 patient files was undertaken. The two most common reasons for the involuntary referral of patients by police were bizarre ideas (33%) and threats of suicide (28%). When 101 patients referred by police were compared with 99 patients from other sources, police referrals were three times more likely to be diagnosed with a mental and behavioural disorder because of psychoactive substance use, less likely to be diagnosed with a mood disorder, and less likely to be diagnosed as psychotic. Police referrals were more likely to have worse functional scores; exhibit aggressive behaviour; spend fewer days in hospital; more likely to be admitted to the psychiatric intensive care unit, and to be secluded. The most important predictor for a police referral was drug or alcohol problems. The study indicates that patients referred by the police were more likely to demonstrate particular characteristics compared with patients referred by other sources.

Tunable remote pinning of domain walls in magnetic nanowires

Domain wall (DW) pinning in ferromagnetic nanowires is in general a complex process. Distortions of the DW shape make quantitative agreement between modeling and experiment difficult. Here we demonstrate pinning using nanometer scale localized stray fields. This type of interaction gives well-characterized, tailorable potential landscapes that do not appreciably distort the DW. Our experimental results are in excellent quantitative agreement with an Arrhenius-Néel model of depinning--a result only possible when the modeled potential profile agrees fully with that experienced by the DW.

Fast domain wall motion in magnetic comb structures

Modern fabrication technology has enabled the study of submicron ferromagnetic strips with a particularly simple domain structure, allowing single, well-defined domain walls to be isolated and characterized. However, these domain walls have complex field-driven dynamics. The wall velocity initially increases with field, but above a certain threshold the domain wall abruptly slows down, accompanied by periodic transformations of the domain wall structure. This behaviour is potentially detrimental to the speed and proper functioning of proposed domain-wall-based devices, and although methods for suppression of the breakdown have been demonstrated in simulations, a convincing experimental demonstration is lacking. Here, we show experimentally that a series of cross-shaped traps acts to prevent transformations of the domain wall structure and increase the domain wall velocity by a factor of four compared to the maximum velocity on a plain strip. Our results suggest a route to faster and more reliable domain wall devices for memory, logic and sensing.

Hand pattern indicates prostate cancer risk

BACKGROUND

The ratio of digit lengths is fixed in utero, and may be a proxy indicator for prenatal testosterone levels.

METHODS

We analysed the right-hand pattern and prostate cancer risk in 1524 prostate cancer cases and 3044 population-based controls.

RESULTS

Compared with index finger shorter than ring finger (low 2D : 4D), men with index finger longer than ring finger (high 2D : 4D) showed a negative association, suggesting a protective effect with a 33% risk reduction (odds ratio (OR) 0.67, 95% confidence interval (CI) 0.57-0.80). Risk reduction was even greater (87%) in age group <60 (OR 0.13, 95% CI 0.09-0.21).

CONCLUSION

Pattern of finger lengths may be a simple marker of prostate cancer risk, with length of 2D greater than 4D suggestive of lower risk.

Magnetization reversal in individual cobalt micro- and nanowires grown by focused-electron-beam-induced-deposition

We systematically study individual micro- and nanometric polycrystalline cobalt wires grown by focused-electron-beam-induced-deposition. The deposits were grown in a range of aspect ratios varying from 1 up to 26. The minimum lateral dimension of the nanowires was 150 nm, for a thickness of 40 nm. Atomic force microscopy images show beam-current-dependent profiles, associated with different regimes of deposition. The magnetization reversal of individual nanowires is studied by means of the spatially resolved magneto-optical Kerr effect. Abrupt switching is observed, with a systematic dependence on the wire's dimensions. This dependence of the coercive field is understood in magnetostatic terms, and agrees well with previous results on cobalt wires grown with different techniques. The influence of compositional gradients along the structural profile on the magnetic reversal is studied by using micromagnetic simulations. This work demonstrates the feasibility of using this technique to fabricate highly pure magnetic nanostructures, and highlights the advantages and disadvantages of the technique with respect to more conventional ones.

Near-field interaction between domain walls in adjacent Permalloy nanowires

The magnetostatic interaction between two oppositely charged transverse domain walls (TDWs) in adjacent Permalloy nanowires is experimentally demonstrated. The dependence of the pinning strength on wire separation is investigated for distances between 13 and 125 nm. The results can be described fully by considering the distribution of magnetic charge within rigid, isolated TDWs. Alternative DW internal structure cannot reproduce this observed dependence. Modeling suggests the TDW internal structure is not appreciably disturbed, and remains rigid although the pinning strength is significant.

Measuring domain wall fidelity lengths using a chirality filter

The motion of transverse domain walls (DWs) in thin Permalloy nanowires has been studied by locally detecting the chirality of the moving DW, using a cross-shaped trap acting as a chirality filter. We find that structural changes of the DW occur over a characteristic minimum distance: the "DW fidelity length." The measured field dependence of the fidelity length is in good qualitative agreement with a 1D analytical model and with published results of numerical simulations and experiments. We also demonstrate extension of the fidelity length to meter length scales using a series of filters.

Influence of a GT repeat element on shear stress responsiveness of the VWF gene promoter

BACKGROUND

Plasma von Willebrand factor (VWF) is mainly derived from endothelial cells, cells that express a large repertoire of genes that are transcriptionally regulated by fluid shear stress. Endothelial VWF expression is not uniform throughout the vasculature, and levels are increased at regions associated with disturbed blood flow and steep gradients of shear stress. It is, however, unknown whether shear stress influences the regulation of VWF gene expression.

OBJECTIVES

Our objective was to evaluate the effect of shear stress on endogenous endothelial VWF mRNA expression and VWF promoter (-2722 to -1224) activity and to determine whether genetic elements modulate this flow-induced expression.

METHODS

A parallel plate flow chamber was used to expose endothelial cells to a shear level of 15 dynes cm(-2) for 24 or 6 h. VWF mRNA expression was analyzed. Various VWF promoter constructs that each contain either SNP haplotypes 1 or 2 and either a 17-GT or a 23-GT repeat element were transfected into endothelial cells, and flow-induced promoter activation was assessed.

RESULTS

When endothelial cells were exposed to shear stress, endogenous VWF mRNA expression increased 1.84-fold and average VWF promoter activity was enhanced 3.4-fold. Single nucleotide polymorphisms at -2708 and -2525, and the shear stress-response element at -1585, are not responsible for the shear stress-induced increase. Rather a GT repeat element at -2124 mediates the increase in activity, and the length of this polymorphic repeat element influences the magnitude of induction.

CONCLUSIONS

Shear stress enhances VWF promoter activity and a polymorphic GT repeat element mediates the stress-induced transactivation.

Diagnostic radiation procedures and risk of prostate cancer

Exposure to ionising radiation is an established risk factor for many cancers. We conducted a case-control study to investigate whether exposure to low dose ionisation radiation from diagnostic x-ray procedures could be established as a risk factor for prostate cancer. In all 431 young-onset prostate cancer cases and 409 controls frequency matched by age were included. Exposures to barium meal, barium enema, hip x-rays, leg x-rays and intravenous pyelogram (IVP) were considered. Exposures to barium enema (adjusted odds ratio (OR) 2.06, 95% confidence interval (CI) 1.01-4.20) and hip x-rays (adjusted OR 2.23, 95% CI 1.42-3.49) at least 5 years before diagnosis were significantly associated with increased prostate cancer. For those with a family history of cancer, exposures to hip x-rays dating 10 or 20 years before diagnosis were associated with a significantly increased risk of prostate cancer: adjusted OR 5.01, 95% CI 1.64-15.31 and adjusted OR 14.23, 95% CI 1.83-110.74, respectively. Our findings show that exposure of the prostate gland to diagnostic radiological procedures may be associated with increased cancer risk. This effect seems to be modified by a positive family history of cancer suggesting that genetic factors may play a role in this risk association.

The influences of genotype, environment, and genotype×environment interaction on wheat quality

Knowledge of the relative contributions of genotype (G), environment (E), and genotype and environment interaction (G × E) effects on wheat (Triticum aestivum L.) quality leads to more effective selection in breeding programs and segregation of more uniform parcels of grain better suited to the needs of customers. Their effects on wheat quality were reviewed using papers obtained from 4 major international databases. The literature is dominated by research from North America, with lesser contributions from Europe, Australia, and the rest of the world. Use of analysis of variance to partition sources of variation due to G, E, and G × E was the most common approach but, more recently, residual maximum likelihood methods that can accommodate large, but unbalanced, datasets have been used. In North America and Europe, the relative contributions of G, E, and G × E varied across studies, but traits associated with protein content were more influenced by E and G × E than those associated with protein quality, dough rheology and starch characteristics, where G effects were more important. Variation in the relative contributions of G, E, and G × E was highly dependent on the G and E sampled. The Australian studies were characterised by a relative lack of G × E, with G and E rankings being similar across the country for the protein quality, dough rheology, and starch quality traits examined in detail. This suggests that, in Australia, more efficient testing of potential cultivars will be possible for these traits, especially when the underlying variation at the gene level is known, and that efficiencies in the design and conduct of trial systems and quality evaluations could be achieved by testing samples from targetted environments without affecting genetic gain and overall crop quality.

63. A FEMINIST EXPLORATION OF WOMEN'S EXPERIENCES OF HAVING A SEXUALLY TRANSMITTED INFECTION

Background and objectives: Sexually transmitted infections (STIs) affect millions of people worldwide and are capable of causing significant physical and psychological harm to individuals and communities. Although STIs can affect any sexually active individual they have more severe consequences for women compared to men, and are capable of causing infant death, infertility, and reproductive cancer. Despite the increasing prevalence of STIs, issues associated with the mental health consequences of these infections remain largely unexplored. However the negative impact on self-esteem and the stigma associated with STIs have been identified as important factors affecting the psychological wellbeing of individuals. This study aims to explore women's experiences and perceptions of having an STI from a feminist perspective. This paper will present initial findings. Methodology: This study utilised a feminist methodology. Data was obtained through qualitative open-ended interviews with the women participants either in person or online and all data was subjected to feminist narrative analysis. Results and conclusion: Data collection and analysis is in progress at the time of abstract submission. It is anticipated that preliminary results will be presented at this sexual health conference. Initial analysis has revealed that stigma, condom negotiation, self-blame, and acceptance/empowerment are major themes within the women participants' stories. This research will contribute to the existing body of literature and provide information to facilitate appropriate care provided by healthcare personnel through gaining insights and understanding into the needs of these women.

Genetic linkage and association analysis in type 1 von Willebrand disease: results from the Canadian type 1 VWD study

BACKGROUND

von Willebrand disease (VWD) is the most common bleeding disorder known in humans, with type 1 VWD representing the majority of cases. Unlike the other variant forms of VWD, type 1 disease represents a complex genetic trait, influenced by both genetic and environmental factors.

AIM

To evaluate the contribution of the von Willebrand factor (VWF) and ABO blood group loci to the type 1 VWD phenotype, and to assess the potential for locus heterogeneity in this condition, we have performed genetic linkage and association studies on a large, unselected type 1 VWD population.

METHOD

We initially collected samples from 194 Canadian type 1 VWD families for analysis. After the exclusion of families found to have either type 2 or type 3 VWD, and pedigrees with samples from single generations, linkage and association analysis was performed on 155 type 1 VWD families.

RESULTS AND CONCLUSION

The linkage study has shown a low heterogeneity LOD score of 2.13 with the proportion of families linked to the VWF gene estimated to be 0.41. Linkage was not detected to the ABO locus in this type 1 VWD population. In the family-based association test, significant association was found between the type 1 VWD phenotype, the quantitative traits, VWF:Ag, VWF:RCo, and FVIII:C and the ABO 'O' and 'A' alleles and the VWF codon 1584 variant. There was also weak association with the -1185 promoter polymorphism and VWF:Ag, VWF:RCo, and FVIII:C plasma levels. These studies provide further evidence to support the role for genetic loci other than VWF and ABO in the pathogenesis of type 1 VWD.

Silicon gel sheeting for preventing and treating hypertrophic and keloid scars

BACKGROUND

Keloid and hypertrophic scars are common and are caused by a proliferation of dermal tissue following skin injury. They cause functional and psychological problems for patients, and their management can be difficult. The use of silicon gel sheeting to prevent and treat hypertrophic scarring is still relatively new, and started in 1981 with treatment of burn scars.

OBJECTIVES

To determine the effectiveness of silicon gel sheeting for: (1) prevention of hypertrophic or keloid scarring in people with newly healed wounds (e.g. post surgery); (2) treatment of established scarring in people with existing keloid or hypertrophic scars.

SEARCH STRATEGY

Trials were identified from searches of the Cochrane Wounds Group Specialised Register (searched September 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2005); MEDLINE (1989 to June 2002); EMBASE (1988 to May 2002); CINAHL (1982 to May 2002) and reference lists of articles and relevant reviews. The major supplier of silicon gel sheeting (Smith and Nephew) was approached for details of unpublished, ongoing and recently published trials.

SELECTION CRITERIA

Any randomised or quasi-randomised controlled trials, or controlled clinical trials comparing silicon gel sheeting for prevention or treatment of hypertrophic or keloid scars against no treatment, placebo, or any other treatment type except surgery.

DATA COLLECTION AND ANALYSIS

All relevant trials were assessed for methodological quality. Data were extracted independently by both reviewers using a standardized form, and the results cross-checked. All trials, meeting the selection criteria were assessed for methodological quality.

MAIN RESULTS

Thirteen trials, involving 559 people, ranging in age from 2 to 81 years, were included in the review. The trials compared adhesive silicon gel sheeting with control; non-silicon gel sheeting; silicon gel plates with added Vitamin E; laser therapy; triamcinolone acetonide injection, and non-adhesive silicon gel sheeting. In the prevention studies, when compared with a no treatment option; whilst silicon gel sheeting reduced the incidence of hypertrophic scarring in people prone to scarring, (RR 0.46, 95% CI 0.21 to 0.98) these studies were highly susceptible to bias. Silicon gel sheeting produced a statistically significant improvement in scar elasticity, (RR 8.60, 95% CI 2.55 to 29.02), but again these studies were highly susceptible to bias.

AUTHORS' CONCLUSIONS

Trials evaluating silicon gel sheeting as a treatment for hypertrophic and keloid scarring are of poor quality and highly susceptible to bias. There is weak evidence of a benefit of silicon gel sheeting as a prevention for abnormal scarring in high risk individuals but the poor quality of research means a great deal of uncertainty prevails.

A comparative study for yield performance and adaptation of some Australian and CIMMYT/ICARDA wheat genotypes grown at selected locations in Australia and the WANA region

A regional adaptation analysis was conducted to provide a basis for effective and efficient wheat germplasm exchange between Australia and the WANA region. A set of 38 Australian and CIMMYT/ICARDA genotypes was tested for grain yield in 29 environments in Australia and the WANA region for 3 years commencing in 1994–95 season. Classification analysis of grain yield data identified 9 genotypic groups and 5 environmental groups with similar patterns in yield performance within each group. Genotypes with similar origin and pedigree were similar in yield performance across environments in Australia and the WANA region. Environmental conditions across both regions showed similarity in discriminating genotypes for their yield performance. Genotypes Attila, Spear, Excalibur, and 82Y:1186 were highest yielding in Australia and the WANA region. However, genotypes Nesser, Pfau/Seri//Bow, Hartog, Vulcan, and Sunland showed wide adaptation across both regions. Genotypes Cranbrook, Genaro 81, Seri 82, Kauz, SUN 190A, and Pgo/Seri 82 showed specific adaptation to favourable environments. Genotypes in each group, based on yield performance, showed differing degrees of yield stability. Pfau/Seri//Bow has the potential for release for commercial production in Australia and the WANA region. The genotypes Pfau/Seri//Bow, Hartog, Sunland, and Vulcan could be used in trials in both regions as indicator varieties to evaluate new breeding lines for mutual exchange between the 2 sets of breeding programs.

Cell-permeable ceramides increase basal glucose incorporation into triacylglycerols but decrease the stimulation by insulin in 3T3-L1 adipocytes

OBJECTIVE

To investigate mechanisms for the regulation of glucose incorporation into triacylgycerols in adipocytes by ceramides, which mediate some actions of tumour necrosis factor-alpha (TNFalpha).

DESIGN

The effects of C(2)- and C(6)-ceramides (N-acetyl- and N-hexanoyl-sphingosines, respectively) on glucose uptake and incorporation into triacylglycerols and pathways of signal tansduction were measured in 3T3-L1 adipocytes.

RESULTS

C(6)-ceramide increased basal 2-deooxyglucose uptake but decreased insulin-stimulated uptake without changing the EC(50) for insulin. Incubating 3T3-L1 adipocytes from 2 to 24 h with C(2)-ceramide progressively increased glucose incorporation into the fatty acid and especially the glycerol moieties of triacylglycerol. These effects were accompanied by increased GLUT1 synthesis resulting from ceramide-induced activation phosphatidylinositol 3-kinase, ribosomal S6 kinase and mitogen-activated protein kinase. C(2)-ceramide also increased p21-activated kinase and protein kinase B activities. However, C(2)-ceramide decreased the insulin-stimulated component of these signalling pathways and also glucose incorporation into triacylglycerol after 2 h.

CONCLUSIONS

Cell-permeable ceramides can mimic some effects of TNFalpha in producing insulin resistance. However, ceramides also mediate long-term effects that enable 3T3 L1 adipocytes to take up glucose and store triacylglycerols in the absence of insulin. These observations help to explain part of the nature and consequence of TNFalpha-induced insulin resistance and the control of fat accumulation in adipocytes in insulin resistance and obesity.

Corrigendum to: A comparative study for yield performance and adaptation of some Australian and CIMMYT/ICARDA wheat genotypes grown at selected locations in Australia and the WANA region

A regional adaptation analysis was conducted to provide a basis for effective and efficient wheat germplasm exchange between Australia and the WANA region. A set of 38 Australian and CIMMYT/ICARDA genotypes was tested for grain yield in 29 environments in Australia and the WANA region for 3 years commencing in 1994–95 season. Classification analysis of grain yield data identified 9 genotypic groups and 5 environmental groups with similar patterns in yield performance within each group. Genotypes with similar origin and pedigree were similar in yield performance across environments in Australia and the WANA region. Environmental conditions across both regions showed similarity in discriminating genotypes for their yield performance. Genotypes Attila, Spear, Excalibur, and 82Y:1186 were highest yielding in Australia and the WANA region. However, genotypes Nesser, Pfau/Seri//Bow, Hartog, Vulcan, and Sunland showed wide adaptation across both regions. Genotypes Cranbrook, Genaro 81, Seri 82, Kauz, SUN 190A, and Pgo/Seri 82 showed specific adaptation to favourable environments. Genotypes in each group, based on yield performance, showed differing degrees of yield stability. Pfau/Seri//Bow has the potential for release for commercial production in Australia and the WANA region. The genotypes Pfau/Seri//Bow, Hartog, Sunland, and Vulcan could be used in trials in both regions as indicator varieties to evaluate new breeding lines for mutual exchange between the 2 sets of breeding programs.

Dissociated ROS production and ceramide generation in sulfasalazine-induced cell death in Raw 264.7 cells

Sulfasalazine (SSZ) is a drug used in inflammatory bowel disease, whose precise mechanism of action remains to be clarified. Here, we report that incubation of Raw 264.7 cells with SSZ but not salicylates [acetylsalicylic acid (ASA), 4-aminosalicylic acid (4-ASA), and 5-ASA] causes a mixed apoptotic and necrotic form of cell death. In contrast to its metabolites, sulfapyridine and 5-ASA, SSZ exposure in Raw 264.7 cells resulted in a threefold increase in ceramide generation, as well as a robust production of reactive oxygen species (ROS). However, inhibition of ceramide production by fumonisin B1 failed to attenuate cell death. Preincubation with catalase, cyclosporin A (CsA), and bongkrekic acid attenuated ROS production. When dead cells were quantified for apoptotic versus necrotic cell death, catalase and N-acetylcysteine reproducibly attenuated apoptosis, whereas CsA, in addition to reducing apoptosis, was observed to dramatically enhance necrosis. In conclusion, the cell-death response induced by SSZ in Raw 264.7 cells involves ROS in the apoptotic limb but is independent of ceramide formation.

Protection against experimental Staphylococcus aureus arthritis by vaccination with clumping factor A, a novel virulence determinant

The importance of the fibrinogen-binding adhesin clumping factor A (ClfA) in the pathogenesis of Staphylococcus aureus septic arthritis was examined in an animal model. The protective effect of active and passive immunization with ClfA also was investigated in S. aureus infection models. The severity of arthritis was markedly reduced in mice challenged intravenously with a clfA mutant, compared with mice infected with the wild-type strain. Mice immunized with recombinant ClfA and challenged with S. aureus developed less-severe arthritis than did mice immunized with a control antigen. Passive immunization of mice with rat and rabbit anti-ClfA antibodies protected against S. aureus arthritis and sepsis-induced death, indicating that the protection by active immunization is antibody mediated. Taken together, these data strongly suggest that ClfA is a crucial virulence determinant for septic arthritis and an excellent target for the generation of immune therapies directed against S. aureus.

5-Aminosalicylate stimulates phospholipase D activity in macrophages

5-Aminosalicylate, which is considered to be the active moiety of sulfasalazine, is one of the most widely used agents for treatment of inflammatory bowel disease. However, its mechanism of action is unclear. In this report, we provide evidence that the phospholipase D pathway is a target for this drug in macrophages. Activation of phospholipase D leads to the generation of important second messengers such as phosphatidic acid, lysophosphatidic acid and diacylglycerol, all of which can regulate cellular responses involved in inflammation. Murine peritoneal macrophages were labeled with [(3)H]myristate, incubated with various drugs, agonists, or inhibitors, and phospholipase D activity was assayed. 5-Aminosalicylate or sulfasalazine stimulated phospholipase D in a time- and concentration-dependent manner. Chelation of extracellular Ca(2+) inhibited phospholipase D activation by either of these drugs whereas pretreatment of macrophages with the tyrosine kinase inhibitor genistein had no effect. Downregulation of protein kinase C by prolonged incubation with phorbol ester completely blocked the activation of phospholipase D. Pertussis toxin decreased the activation of phospholipase D. The levels of inositol 1,4,5-trisphosphate increased by 260% after treatment of macrophages with 5-aminosalicylate. A phosphoinositide-specific phospholipase C inhibitor U73122 blocked phospholipase D activation completely. Interestingly, long-term preincubation of the macrophages with a relatively low concentration of 5-aminosalicylate that did not stimulate phospholipase D activity by itself, potentiated the effect of phorbol ester-induced activation of phospholipase D. Taken together, these results show that 5-aminosalicylate activates phospholipase D via a pathway involving inositol 1,4,5-trisphosphate generation, calcium fluxes, and Gi/Go. Although the mechanisms by which phospholipase D activation by 5-aminosalicylate or sulfasalazine might attenuate inflammatory responses in the intestine remain to be defined, these results highlight a novel potential mechanism of action for these drugs.

The relationship between community psychiatric nurses and clients with severe and persistent mental illness: the client's experience

The aim of this phenomenological study was to construct an interpretation of the experience of nurse-patient relationships, in the context of community psychiatric nursing. The purpose of this paper is to focus on the experience of the relationship from the perspective of the clients. Themes of 'having someone looking out for me', 'working in collaboration', and 'being understood and gaining understanding' were identified. This thematic structure was used to understand the meaning of the relationship for the clients. Implications for practice, education, clinical supervision and mental health services are discussed.

Species-specific PCR for the identification of ovine, porcine and chicken species in meta and bone meal (MBM)

BSE, first identified in the UK in 1986 is thought to have arisen from feeding scrapie infected Meat and Bone Meal (MBM), produced under sub-optimal conditions, to cattle. For quality and safety reasons there is a requirement for a good analytical test for the surveillance of processed MBM. This study describes species-specific PCR assays for the identification of ovine, porcine and poultry species in MBM. A comparison between two distinct DNA extraction methods, i.e. the silicaguanidiumthiocyanate DNA isolation procedure and a commercial DNA extraction kit, is also presented. Application of this technology to species identification in industrial MBM was investigates as part of this study.

Yield performance and adaptation of some Australian and CIMMYT/ICARDA developed wheat genotypes in the West Asia North Africa (WANA) region

A set of 29 advanced breeding lines and named cultivars from different breeding programs in Australia was compared with 18 genotypes developed by the CIMMYT/ICARDA breeding programs for their adaptation and yield performance using 5 locations in the WANA region for 2 years. Classification analysis identified 13 CIMMYT/ICARDA genotypes that had a pattern in yield performance similar to 2 Australian cultivars, Leichhardt and Hartog. The classification of environments effectively identified trials that experienced heat stress and received supplementary irrigation. Most of the genotypes developed by the CIMMYT/ICARDA breeding programs showed wide adaptation in the WANA region. Genotypes developed for Australian Mediterranean environments failed to show wide adaptation in the WANA region. However, many Australian genotypes showed specific adaptation to heat-stressed environments. Variation among Australian genotypes for disease resistance and heat tolerance couldbe used for wheat improvement in the WANA region.