Strain-engineering Mott-insulating La2CuO4.

The transition temperature Tc of unconventional superconductivity is often tunable. For a monolayer of FeSe, for example, the sweet spot is uniquely bound to titanium-oxide substrates. By contrast for La2-xSrxCuO4 thin films, such substrates are sub-optimal and the highest Tc is instead obtained using LaSrAlO4. An outstanding challenge is thus to understand the optimal conditions for superconductivity in thin films: which microscopic parameters drive the change in Tc and how can we tune them? Here we demonstrate, by a combination of x-ray absorption and resonant inelastic x-ray scattering spectroscopy, how the Coulomb and magnetic-exchange interaction of La2CuO4 thin films can be enhanced by compressive strain. Our experiments and theoretical calculations establish that the substrate producing the largest Tc under doping also generates the largest nearest neighbour hopping integral, Coulomb and magnetic-exchange interaction. We hence suggest optimising the parent Mott state as a strategy for enhancing the superconducting transition temperature in cuprates.

Decoupling Carrier Concentration and Electron-Phonon Coupling in Oxide Heterostructures Observed with Resonant Inelastic X-Ray Scattering.

We report the observation of multiple phonon satellite features in ultrathin superlattices of the form nSrIrO_{3}/mSrTiO_{3} using resonant inelastic x-ray scattering (RIXS). As the values of n and m vary, the energy loss spectra show a systematic evolution in the relative intensity of the phonon satellites. Using a closed-form solution for the RIXS cross section, we extract the variation in the electron-phonon coupling strength as a function of n and m. Combined with the negligible carrier doping into the SrTiO_{3} layers, these results indicate that the tuning of the electron-phonon coupling can be effectively decoupled from doping. This work both showcases a feasible method to extract the electron-phonon coupling in superlattices and unveils a potential route for tuning this coupling, which is often associated with superconductivity in SrTiO_{3}-based systems.

Doping Evolution of Magnetic Order and Magnetic Excitations in (Sr_{1-x}La_{x})_{3}Ir_{2}O_{7}.

We use resonant elastic and inelastic x-ray scattering at the Ir-L_{3} edge to study the doping-dependent magnetic order, magnetic excitations, and spin-orbit excitons in the electron-doped bilayer iridate (Sr_{1-x}La_{x})_{3}Ir_{2}O_{7} (0≤x≤0.065). With increasing doping x, the three-dimensional long range antiferromagnetic order is gradually suppressed and evolves into a three-dimensional short range order across the insulator-to-metal transition from x=0 to 0.05, followed by a transition to two-dimensional short range order between x=0.05 and 0.065. Because of the interactions between the J_{eff}=1/2 pseudospins and the emergent itinerant electrons, magnetic excitations undergo damping, anisotropic softening, and gap collapse, accompanied by weakly doping-dependent spin-orbit excitons. Therefore, we conclude that electron doping suppresses the magnetic anisotropy and interlayer couplings and drives (Sr_{1-x}La_{x})_{3}Ir_{2}O_{7} into a correlated metallic state with two-dimensional short range antiferromagnetic order. Strong antiferromagnetic fluctuations of the J_{eff}=1/2 moments persist deep in this correlated metallic state, with the magnon gap strongly suppressed.

Optimised concentration and purification of retroviruses using membrane chromatography.

The ability of an anion exchange membrane to purify a γ-retrovirus was assessed and optimised with respect to different loading and wash buffers. Recoveries of infectious virus greater than 50% were consistently obtained, while specific titre was increased up to one thousand fold when compared to the material loaded. Specific proteins removed and retained by this optimised process were identified by mass spectrometry. It was possible to successfully bind and elute the equivalent of 1.27 × 10(8) Ifu/ml of ion exchange membrane. This could then be highly concentrated, with infectious virus concentrated to a maximum of 420-fold compared to the load.

A computational simulation study of the influence of helmet wearing on head injury risk in adult cyclists.

Evidence for the effectiveness of cycle helmets has relied either on simplified experiments or complex statistical analysis of patient cohorts or populations. This study directly assesses the effectiveness of cycle helmets over a range of accident scenarios, from basic loss of control to vehicle impact, using computational modelling. Simulations were performed using dynamics modelling software (MADYMO) and models of a 50% Hybrid III dummy, a hybrid cross bicycle and a car. Loss of control was simulated by a sudden turn of the handlebars and striking a curb, side and rear-on impacts by a car were also simulated. Simulations were run over a representative range of cycle speeds (2.0-14.0 m s(-1)) and vehicle speeds (4.5-17.9 m s(-1)). Bicycle helmets were found to be effective in reducing the severity of head injuries sustained in common accidents. They reduced the risk of an AIS>3 injury, in cases with head impacts, by an average of 40%. In accidents that would cause up to moderate (AIS=2) injuries to a non-helmeted rider, helmets eliminated the risk of injury. Helmets were also found to be effective in preventing fatal head injuries in some instances. The effectiveness of helmets was demonstrated over the entire range of cycle speeds studied, up to and including 14 m s(-1). There was no evidence that helmet wearing increased the risk of neck injury, indeed helmets were found to be protective of neck injuries in many cases. Similarly, helmets were found to offer an increase in protection even when an increase in cycle speed due to risk compensation was taken into consideration.

MADYMO simulation of children in cycle accidents: a novel approach in risk assessment.

Head injuries are a significant cause of death and injury to child cyclists both on and off the road. Current evaluations of the effectiveness of cycle helmets rely on simplified mechanical testing or the analysis of aggregated accident statistics. This paper presents a direct evaluation of helmet efficacy by using computational modelling to simulate a range of realistic accident scenarios, including loss of control, collision with static objects and vehicle impact. A 6-year-old cyclist was modelled (as a Hybrid III 6-year-old dummy), in addition to a typical children's bicycle and a vehicle using the MADYMO dynamics software package. Simulations were performed using ranges of cyclist position, cycle speed and vehicle speed with and without a helmet that meets current standards. Wearing a cycle helmet was found to reduce the probability of head injuries, reducing the average probability of fatality over the scenarios studied from 40% to 0.3%. Similarly, helmet wearing reduced the probability of neck injuries (average probability of fatality reduced from 11% to 1%). There was no evidence that helmet wearing increased the severity of brain or neck injuries caused by rotational accelerations; in fact these were slightly reduced. Similarly, there was no evidence that increased cycling speed, such as might result from helmet related risk compensation, increased the probability of head injury.

The sensitivity of the calculation of ΔV to vehicle and impact parameters.

ΔV is frequently used to describe collision severity, and is often used by accident investigators to estimate speeds of vehicles prior to a collision, and by researchers looking for correlations between severity and outcome. This study identifies how ΔV varies over a wide range of input uncertainties allowing the direct comparison of different methods of input data collection in terms of their effect on uncertainty in the calculation of ΔV. Software was developed to implement this sensitivity analysis and was validated against examples presented in the CRASH3 manual. The findings are therefore representative of, and relevant to, commercially available tools such as CRASH3 and AIDamage. It is possible to measure the vehicle and collision parameters with sufficient accuracy to determine ΔV to a level of precision that is useful to predict occupant fatality. In many cases, ΔV is largely insensitive to the input parameter and category values or values determined from photographs may be used. A vehicle specific value of the stiffness parameter B should be used. Direct measurement of crush measurements and vehicle mass (including the best estimates of fluid loss) should be used. Similarly the mass of occupants and cargo should be measured directly rather than estimated from 50th centile values. Calculation of ΔV is sensitive to PDOF which should be measured with a precision of better than ±6°.

Lentivirus capture directly from cell culture with Q-functionalised microcapillary film chromatography.

A new disposable adsorbent material for fast anion-exchange capture of nano-complexes without prefiltering, clarification or pre-processing of samples was developed based on plastic microcapillary films (MCFs). An MCF containing 19 parallel microcapillaries, each with a mean internal diameter of 142 ± 10 µm, was prepared using a melt extrusion process from an ethylene-vinyl alcohol copolymer (EVOH). The MCF internal surfaces were functionalised using branched chain chemistries to attach quaternary amine groups producing an anion-exchange adsorbent. The purification of nano-complexes using this newly fabricated MCF-EVOH-Q was successfully demonstrated with the capture of lentivirus from pre-filtered culture harvest. This 5m chromatographic substrate was found to bind and elute ∼40% of bound lentivirus or 2.5 × 10(6)infectious units (ifu). The unique properties of this chromatographic substrate that allow the passage of large particulates was further demonstrated with the capture of lentiviral particles from unfiltered un-processed culture media containing cells and cell debris. Using this approach, 56% or 1 × 10(7)ifu of captured lentivirus was eluted. A device based on this new material might be used at an early stage in clinical lentiviral production to harvest lentiviral particles, directly from bioreactors.

Rapid relief of acute sore throat with AMC/DCBA throat lozenges: randomised controlled trial.

AIM: As antibiotics are generally not recommended for the treatment of acute sore throat, the availability of clinically efficacious, over-the-counter (OTC) treatment alternatives is becoming increasingly important. This study was designed to determine the analgesic properties of amylmetacresol and 2,4-dichlorobenzyl alcohol (AMC/DCBA) throat lozenges (Strepsils) in the relief of acute sore throat caused by upper respiratory tract infections. METHODS: Patients (n = 310) were randomly assigned to receive AMC/DCBA throat lozenges (n = 155) or non-medicated placebo lozenges (n = 155). After baseline assessments, patients completed three rating assessments at 10 timepoints from 5 to 20 min after first dose. Subsequent lozenges were taken as required, and assessments were made at the end of Day 1, 24 h after first dose, and at the end of Days 2 and 3. Analgesic properties were assessed by comparing severity of throat soreness and sore throat relief ratings. Difficulty in swallowing and functional impairment scores were also assessed. RESULTS: Amylmetacresol/DCBA throat lozenges reduced throat soreness at 5 min after first dose, which persisted for 2 h and was significantly different vs. non-medicated lozenges at all assessment timepoints for the duration of the 3-day study. Similar significant effects were observed with sore throat relief, easing of difficulty with swallowing and functional impairment scores. There were no differences in adverse events reported between treatment groups. CONCLUSION: Amylmetacresol/DCBA throat lozenges provide rapid analgesic effects that last for 2 h, providing ongoing relief long after the lozenge has dissolved. The superior analgesic effects and improvements in functional impairment scores observed with AMC/DCBA throat lozenges translate into pain relief benefits that are clinically meaningful and are thus a suitable OTC treatment option for patients in the self-management of acute sore throat.

The implications of stress patterns in the vertebral body under axial support of an artificial implant.

Clinical studies show an association between changed load patterns both in the disc and its adjacent vertebral body, with painful degenerated discs. This suggests that failure to restore the normal loading pattern on implantation of a disc replacement could be a cause of lower clinical success rate. In the present study the variations of load patterns in the vertebra after disc implantation was studied using a simplified finite element models of natural and artificial discs. The effect of implant size and presence of voids at the implant-bony endplate interface were studied, for the worst case scenario of no bone remodelling. An altered stress pattern was observed in the vertebrae of implanted segments. The use of smaller size implants and presence of voids at the interface caused localized stress concentration in the endplate and adjacent cancellous bone. The study results support the hypothesis that current implants fail to restore normal loading patterns in the vertebral body, and the localized high stress regions could be the source of pain, and the cause of low success rate of TDRs.

The internal pressure and stress environment of the scoliotic intervertebral disc--a review.

The aetiology, in terms of both initiation and progression, of the deformity in idiopathic scoliosis is at present unclear. Even in neuromuscular cases, the mechanisms underlying progression are not fully elucidated. It is thought, however, that asymmetrical loading is involved in the progression of the disease, with evidence mainly from animal studies and modelling. There is, however, very little direct information as to the origin or mechanism of action of these forces in the scoliotic spine. This review describes the concept of intervertebral disc pressure or stress and examines possible measurement techniques. The biological and mechanical consequences of abnormalities in these parameters are described. Future possible studies and their clinical significance are also briefly discussed. Techniques of pressure measurement have culminated in the development of 'pressure profilometry', which provides stress profiles across the disc in mutually perpendicular axes. A hydrated intervertebral disc exhibits mainly hydrostatic behaviour. However, in pathological states such as degeneration and scoliosis, non-hydrostatic behaviour predominates and annular peaks of stress occur. Recent studies have shown that, in scoliosis, high hydrostatic pressures are seen with asymmetrical stresses from concave to convex sides. These abnormalities could influence both disc and endplate cellular activity directly, causing asymmetrical growth and matrix changes. In addition, disc cells could be influenced via nutritional changes consequent to end-plate calcification. Evidence suggests that the stress environment of the scoliotic disc is abnormal, probably generated by high and asymmetrical loading of non-muscular origin. If present in the scoliotic spine during daily activities, this could generate a positive feedback of cellular changes, resulting in curve progression. Future advances in understanding may rely on the development of computer models owing to the difficulties of in-vivo invasive measurements.

Adherence of academic geriatric practitioners to osteoporosis screening guidelines.

OBJECTIVES: To examine the bone mineral density (BMD) testing habits of geriatricians and geriatric fellows at the University of Connecticut fellowship training program to evaluate their adherence screening guidelines. DESIGN: Retrospective chart review. SETTING: University based academic geriatric practice in Farmington, CT. PARTICIPANTS: Chart review of two hundred female patients over age 65 under care of seven faculty geriatricians and eight geriatric fellows in training. MEASUREMENTS: Data collected included BMD testing status, patient's osteoporosis risk factors and functional status. RESULTS: Physicians ordered BMD tests in 151 (76%) patients; 128 (64%) had a bone mineral density test within three years. A personal history of fracture was the only osteoporosis risk factor that correlated to higher rates of osteoporosis testing. Physicians were more likely to order BMD screening in younger patients (92% in 65-74 vs. 74% in ages 85+, P=.031), patients independent in activities of daily living (72% vs. 32, P=.002), and patients without dementia (70% vs.37%, p=.007). BMD testing results found 82% with osteopenia or osteoporosis. CONCLUSIONS: A geriatric group that is highly attuned to bone health demonstrated more optimal adherence to OP testing guidelines for all "at-risk" older women and better than reported previously. Functional status more strongly predicted BMD testing than osteoporosis risk factors. This study suggests that with improved physician education and familiarity with the disease, high rates of BMD testing for earlier identification of geriatric patients at risk for osteoporosis are achievable.

The effect of leg fracture level and vehicle front-end geometry on pedestrian knee injury and response.

In this study a MADYMO (mathematical dynamic modelling) model has been used to identify the influence of leg fracture on the injuries sustained by the pedestrian during front end impact with a vehicle. A factorial study of a MADYMO pedestrian and vehicle model are used to investigate the effect of different leg fracture tolerances, geometry, and vehicle compliance on the criteria measured in the European Enhanced Vehicle-safety Committee (EEVC) pedestrian safety tests. These criteria include knee bending, knee shear response, and lower leg bone (tibia) acceleration. The main study examines the spread of typical values of lower limb tolerance based on reported literature and contrasts the response of weaker, low-strength bones, normal tolerance, and limbs which do not fracture. Results show that knee bending angles and therefore ligament strains are significantly increased when fracture does not occur, and are decreased in bones exhibiting a low-strength response. Bone fracture tolerance is shown to be a significant parameter influencing knee bending. The parameters are compared to show that knee shear is significantly influenced by vehicle bumper compliance and that both criteria are heavily influenced by bumper height. Vehicles with more aggressive geometry, higher bumpers, and larger bumper lead were considered for comparative purposes.

A one-dimensional theoretical prediction of the effect of reduced end-plate permeability on the mechanics of the intervertebral disc.

The permeability of the cartilage end-plate (CEP) may play an important role in intervertebral disc (IVD) degeneration by controlling the convective and diffusive transport of metabolites into the nucleus pulposus. A one-dimensional poroelastic model was used to predict the effect of a CEP of lower permeability than the disc tissue on the convective transfer into and out of the IVD. With decreasing CEP permeability, associated with degeneration, the model predicted that the change in disc height with time became more linear; the disc could not rehydrate as quickly; and internal fluid movement was slowed. This study has shown that CEP permeability will only markedly have an effect on fluid movement, and hence convective nutrition, if the permeability of the CEP is reduced to less than that of the disc tissue.

Rigid-body modelling of shaken baby syndrome.

Recent reassessment of the literature on the shaken baby syndrome (SBS) has revealed a lack of scientific evidence and understanding of all aspects of the syndrome. In particular, studies have been unable to clarify the mechanisms of injury, indicating that impact, rather than shaking alone, is necessary to cause the type of brain damage observed. Rigid-body modelling (RBM) was used to investigate the effect of neck stiffness on head motion and head-torso impacts as a possible mechanism of injury. Realistic shaking data obtained from an anthropometric test dummy (ATD) was used to simulate shaking. In each study injury levels for concussion were exceeded, though impact-type characteristics were required to do so in the neck stiffness study. Levels for the type of injury associated with the syndrome were not exceeded. It is unlikely that further gross biomechanical investigation of the syndrome will be able to significantly contribute to the understanding of SBS. Current injury criteria are based on high-energy, single-impact studies. Since this is not the type of loading in SBS it is suggested that their application here is inappropriate and that future studies should focus on injury mechanisms in low-energy cyclic loading.

Demonstration of the appearance of the paraspinal musculoligamentous structures of the cervical spine using ultrasound.

The application of ultrasound in the imaging of the neck has primarily focussed on anterior structures (e.g., thyroid gland). Structures located on the posterior aspect of the neck have received little attention. This study illustrates the capability of modern ultrasound equipment in visualising the musculoligamentous structures of the neck, particularly the paraspinal musculature. Ten healthy adult volunteers (6 female; 4 male) underwent ultrasound examination of the cervical spine. A standardised technique for transducer placement was adopted and successive images of the neck of each subject were obtained. Spatial compound (extended field of view) images were obtained in subjects using one of two different ultrasound systems. Images of structures produced by ultrasound were compared to those achieved with magnetic resonance imaging in three subjects. Identification of key landmarks aided orientation and identification of structures. The internal architecture of the musculoligamentous structures of the cervical spine, especially the posterior neck muscles, was demonstrated well using ultrasound. Our study showed that modern ultrasound equipment is capable of producing clear images of the posterior cervical spine musculature and certain bony features.

Musculoskeletal motion flow fields using hierarchical variable-sized block matching in ultrasonographic video sequences.

We examine tissue deformations using non-invasive dynamic musculoskeletal ultrasonograhy, and quantify its performance on controlled in vitro gold standard (groundtruth) sequences followed by clinical in vivo data. The proposed approach employs a two-dimensional variable-sized block matching algorithm with a hierarchical full search. We extend this process by refining displacements to sub-pixel accuracy. We show by application that this technique yields quantitatively reliable results.

Fear of recurrence and possible cases of anxiety and depression in orofacial cancer patients.

Recurrence risk in orofacial cancer patients is relatively high in comparison to other cancers. Little information exists on whether patients are unduly concerned over the possibility of recurrence and the association of this concern with psychological morbidity. Aim of study was to assess fear of recurrence and psychological morbidity in orofacial cancer patients. Two samples of patients with orofacial cancer were followed prospectively. First sample (n = 87) were consecutively drawn 3 months and 7 months following initial treatment. Second sample (n = 100) were cross-sectionally drawn from out-patient list and followed 2 years later. A single question item was employed to assess fear of recurrence used in previous work. Hospital Anxiety and Depression Scale was adopted as the measure of psychological morbidity. A prospective survey design was employed. Over 80% of patients expressed concern over the possibility of recurrence at 3 months post treatment. This level reduced to 72% at 7 months (P=0.06). Approximately two-thirds of patients sampled cross-sectionally were concerned at both assessment occasions. Psychological morbidity was greatest at 3 months post treatment (possible cases: anxiety 37% and depression 28%). Women were more likely to report anxiety (at possible case level) than men 3 months following treatment (P<0.05). Patients aged 65 or more years were less concerned about recurrence. This effect was significant on both occasions that sample two patients were assessed (P's<0.002). Very few patients who expressed no concern about recurrence, at 3 months, were found to report anxiety or depression sufficient to be recognized as a possible case (3 and 0% respectively). The positive association between psychological morbidity and fears of recurrence was significant at the majority of data collection points, with the exception that depression was more independent of these concerns.