THE EFFECT OF ACCURACY CONSTRAINTS ON LOWER LIMB JOINT CONTRIBUTIONS DURING THE INSTEP SOCCER KICK

The aim of this study was to quantify the effect of accuracy constraints on the kinematics of the soccer instep kick with specific reference to the relative contributions of the segments of the kicking leg. Eight university level soccer players were recruited into the study. Targets of three sizes were positioned and upon a verbal cue the subjects kicked the ball towards the requested target. For each, successful, kick the lower limb 3-dimensional kinematics and relative joint contributions in the local flexion-extension plane immediately prior to impact were recorded. We found foot speeds decreased significantly for the smaller targets. Soccer kicks between the no target and small target significantly increased the contribution of the ankle joint by 24%. This was at the expense of decreases in both the knee (10%) and hip (14%) contributions. Incorporating targets in soccer kicking affects the proximal to distal transition and relative joint contributions of the lower limb

Monodisperse Cylindrical Micelles and Block Comicelles of Controlled Length in Aqueous Media

Cylindrical block copolymer micelles have shown considerable promise in various fields of biomedical research. However, unlike spherical micelles and vesicles, control over their dimensions in biologically relevant solvents has posed a key challenge that potentially limits in depth studies and their optimization for applications. Here, we report the preparation of cylindrical micelles of length in the wide range of 70 nm to 1.10 μm in aqueous media with narrow length distributions (length polydispersities <1.10). In our approach, an amphiphilic linear-brush block copolymer, with high potential for functionalization, was synthesized based on poly­(ferrocenyldimethylsilane)-<i>b</i>-poly­(allyl glycidyl ether) (PFS-<i>b</i>-PAGE) decorated with triethylene glycol (TEG), abbreviated as PFS-<i>b</i>-(PEO-<i>g</i>-TEG). PFS-<i>b</i>-(PEO-<i>g</i>-TEG) cylindrical micelles of controlled length with low polydispersities were prepared in <i>N</i>,<i>N</i>-dimethylformamide using small seed initiators via living crystallization-driven self-assembly. Successful dispersion of these micelles into aqueous media was achieved by dialysis against deionized water. Furthermore, B–A–B amphiphilic triblock comicelles with PFS-<i>b</i>-poly­(2-vinylpyridine) (P2VP) as hydrophobic “B” blocks and hydrophilic PFS-<i>b</i>-(PEO-<i>g</i>-TEG) “A” segments were prepared and their hierarchical self-assembly in aqueous media studied. It was found that superstructures formed are dependent on the length of the hydrophobic blocks. Quaternization of P2VP was shown to cause the disassembly of the superstructures, resulting in the first examples of water-soluble cylindrical multiblock comicelles. We also demonstrate the ability of the triblock comicelles with quaternized terminal segments to complex DNA and, thus, to potentially function as gene vectors

Transformation and patterning of supermicelles using dynamic holographic assembly

Although the solution self-assembly of block copolymers has enabled the fabrication of a broad range of complex, functional nanostructures, their precise manipulation and patterning remain a key challenge. Here we demonstrate that spherical and linear supermicelles, supramolecular structures held together by non-covalent solvophobic and coordination interactions and formed by the hierarchical self-assembly of block copolymer micelle and block comicelle precursors, can be manipulated, transformed and patterned with mediation by dynamic holographic assembly (optical tweezers). This allows the creation of new and stable soft-matter superstructures far from equilibrium. For example, individual spherical supermicelles can be optically held in close proximity and photocrosslinked through controlled coronal chemistry to generate linear oligomeric arrays. The use of optical tweezers also enables the directed deposition and immobilization of supermicelles on surfaces, allowing the precise creation of arrays of soft-matter nano-objects with potentially diverse functionality and a range of applications

Microfibres and macroscopic films from the coordination-driven hierarchical self-assembly of cylindrical micelles

Anisotropic nanoparticles prepared from block copolymers are of growing importance as building blocks for the creation of synthetic hierarchical materials. However, the assembly of these structural units is generally limited to the use of amphiphilic interactions. Here we report a simple, reversible coordination-driven hierarchical self-assembly strategy for the preparation of micron-scale fibres and macroscopic films based on monodisperse cylindrical block copolymer micelles. Coordination of Pd(0) metal centres to phosphine ligands immobilized within the soluble coronas of block copolymer micelles is found to induce intermicelle crosslinking, affording stable linear fibres comprised of micelle subunits in a staggered arrangement. The mean length of the fibres can be varied by altering the micelle concentration, reaction stoichiometry or aspect ratio of the micelle building blocks. Furthermore, the fibres aggregate on drying to form robust, self-supporting macroscopic micelle-based thin films with useful mechanical properties that are analogous to crosslinked polymer networks, but on a longer length scale

Current Preclinical Testing of New Hip Arthroplasty Technologies Does Not Reflect Real-World Loadings: Capturing Patient-Specific and Activity-Related Variation in Hip Contact Forces

Background: Total hip replacement (THR) implants are routinely tested for their tribological performance through regulatory pre-clinical wear testing (e.g. ISO-14242). The standardized loading conditions defined in these tests consist of simplified waveforms, which do not specifically represent in vivo loads in different groups of patients. The aim of this study was to investigate, through musculoskeletal modelling, patient-specific and activity-related variation in hip contact forces (HCFs) in a large cohort of THR patients during common activities of daily living (ADLs). Methods: 132 THR patients participated in a motion-capture analysis while performing different ADLs, including walk, fast walk, stair ascent and descent (locomotor); sit-to-stand, stand-to-sit, squat and lunge (non-locomotor). HCFs were then calculated using the AnyBody Modelling System and qualitatively compared across all activities. The influence of gender on HCFs was analysed through statistical parametric mapping (SPM) analysis. Results: Systematic differences were found in HCF magnitudes and individual components in both locomotor and non-locomotor ADLs. The qualitative analysis of the ADLs revealed a large range and a large variability of forces experienced at the hip during different activities. Significant differences in the three-dimensional loading patterns were observed between males and females across most activities. Conclusions: THR patients present a large variability in the forces experienced at the hip joint during their daily life. The inter-patient variation might partially explain the heterogeneity observed in implant survival rates. A more extensive pre-clinical implant testing standard, under clinically relevant loading conditions has been advocated to better predict and avoid clinical wear problems

Abundance and species diversity hotspots of tracked marine predators across the North American Arctic

Aim: Climate change is altering marine ecosystems worldwide and is most pronounced in the Arctic. Economic development is increasing leading to more disturbances and pressures on Arctic wildlife. Identifying areas that support higher levels of predator abundance and biodiversity is important for the implementation of targeted conservation measures across the Arctic. Location: Primarily Canadian Arctic marine waters but also parts of the United States, Greenland and Russia. Methods: We compiled the largest data set of existing telemetry data for marine predators in the North American Arctic consisting of 1,283 individuals from 21 species. Data were arranged into four species groups: (a) cetaceans and pinnipeds, (b) polar bears Ursus maritimus (c) seabirds, and (d) fishes to address the following objectives: (a) to identify abundance hotspots for each species group in the summer–autumn and winter–spring; (b) to identify species diversity hotspots across all species groups and extent of overlap with exclusive economic zones; and (c) to perform a gap analysis that assesses amount of overlap between species diversity hotspots with existing protected areas. Results: Abundance and species diversity hotpots during summer–autumn and winter–spring were identified in Baffin Bay, Davis Strait, Hudson Bay, Hudson Strait, Amundsen Gulf, and the Beaufort, Chukchi and Bering seas both within and across species groups. Abundance and species diversity hotpots occurred within the continental slope in summer–autumn and offshore in areas of moving pack ice in winter–spring. Gap analysis revealed that the current level of conservation protection that overlaps species diversity hotspots is low covering only 5% (77,498 km 2 ) in summer–autumn and 7% (83,202 km 2 ) in winter–spring. Main conclusions: We identified several areas of potential importance for Arctic marine predators that could provide policymakers with a starting point for conservation measures given the multitude of threats facing the Arctic. These results are relevant to multilevel and multinational governance to protect this vulnerable ecosystem in our rapidly changing world

Anthropometric indices of Gambian children after one or three annual rounds of mass drug administration with azithromycin for trachoma control.

BACKGROUND: Mass drug administration (MDA) with azithromycin, carried out for the control of blinding trachoma, has been linked to reduced mortality in children. While the mechanism behind this reduction is unclear, it may be due, in part, to improved nutritional status via a potential reduction in the community burden of infectious disease. To determine whether MDA with azithromycin improves anthropometric indices at the community level, we measured the heights and weights of children aged 1 to 4 years in communities where one (single MDA arm) or three annual rounds (annual MDA arm) of azithromycin had been distributed. METHODS: Data collection took place three years after treatment in the single MDA arm and one year after the final round of treatment in the annual MDA arm. Mean height-for-age, weight-for-age and weight-for-height z scores were compared between treatment arms. RESULTS: No significant differences in mean height-for-age, weight-for-age or weight-for-height z scores were found between the annual MDA and single MDA arms, nor was there a significant reduction in prevalence of stunting, wasting or underweight between arms. CONCLUSIONS: Our data do not provide evidence that community MDA with azithromycin improved anthropometric outcomes of children in The Gambia. This may suggest reductions in mortality associated with azithromycin MDA are due to a mechanism other than improved nutritional status

Development of a transparent interactive decision interrogator to facilitate the decision-making process in health care.

BACKGROUND: Decisions about the use of new technologies in health care are often based on complex economic models. Decision makers frequently make informal judgments about evidence, uncertainty, and the assumptions that underpin these models. OBJECTIVES: Transparent interactive decision interrogator (TIDI) facilitates more formal critique of decision models by decision makers such as members of appraisal committees of the National Institute for Health and Clinical Excellence in the UK. By allowing them to run advanced statistical models under different scenarios in real time, TIDI can make the decision process more efficient and transparent, while avoiding limitations on pre-prepared analysis. METHODS: TIDI, programmed in Visual Basic for applications within Excel, provides an interface for controlling all components of a decision model developed in the appropriate software (e.g., meta-analysis in WinBUGS and the decision model in R) by linking software packages using RExcel and R2WinBUGS. TIDI's graphical controls allow the user to modify assumptions and to run the decision model, and results are returned to an Excel spreadsheet. A tool displaying tornado plots helps to evaluate the influence of individual parameters on the model outcomes, and an interactive meta-analysis module allows the user to select any combination of available studies, explore the impact of bias adjustment, and view results using forest plots. We demonstrate TIDI using an example of a decision model in antenatal care. CONCLUSION: Use of TIDI during the NICE appraisal of tumor necrosis factor-alpha inhibitors (in psoriatic arthritis) successfully demonstrated its ability to facilitate critiques of the decision models by decision makers

Dimensional control and morphological transformations of supramolecular polymeric nanofibers based on cofacially-stacked planar amphiphilic platinum(II) complexes

Square-planar platinum­(II) complexes often stack cofacially to yield supramolecular fiber-like structures with interesting photophysical properties. However, control over fiber dimensions and the resulting colloidal stability is limited. We report the self-assembly of amphiphilic Pt­(II) complexes with solubilizing ancillary ligands based on polyethylene glycol [PEG_<i>n</i>, where <i>n</i> = 16, 12, 7]. The complex with the longest solubilizing PEG ligand, <b>Pt-PEG</b>_<b>16</b>, self-assembled to form polydisperse one-dimensional (1D) nanofibers (diameters <5 nm). Sonication led to short seeds which, on addition of further molecularly dissolved <b>Pt-PEG</b>_<b>16</b> complex, underwent elongation in a “living supramolecular polymerization” process to yield relatively uniform fibers of length up to <i>ca</i>. 400 nm. The fiber lengths were dependent on the <b>Pt-PEG</b>_<b>16</b> complex to seed mass ratio in a manner analogous to a living covalent polymerization of molecular monomers. Moreover, the fiber lengths were unchanged in solution after 1 week and were therefore “static” with respect to interfiber exchange processes on this time scale. In contrast, similarly formed near-uniform fibers of <b>Pt-PEG</b>_<b>12</b> exhibited dynamic behavior that led to broadening of the length distribution within 48 h. After aging for 4 weeks in solution, <b>Pt-PEG</b>_<b>12</b> fibers partially evolved into 2D platelets. Furthermore, self-assembly of <b>Pt-PEG</b>_<b>7</b> yielded only transient fibers which rapidly evolved into 2D platelets. On addition of further fiber-forming Pt complex (<b>Pt-PEG</b>_<b>16</b>), the platelets formed assemblies <i>via</i> the growth of fibers selectively from their short edges. Our studies demonstrate that when interfiber dynamic exchange is suppressed, dimensional control and hierarchical structure formation are possible for supramolecular polymers through the use of kinetically controlled seeded growth methods

Assessing the diagnostic accuracy of the identification of hyperkinetic disorders following the introduction of government guidelines in England

<p>Abstract</p> <p>Background</p> <p>Previous studies have suggested that both underdiagnosis and overdiagnosis routinely occur in ADHD and hyperkinesis (hyperkinetic disorders). England has introduced governmental guidelines for these disorders' detection and treatment, but there has been no study on clinical diagnostic accuracy under such a regime.</p> <p>Methods</p> <p>All open cases in three Child and Adolescent Mental Health Services (CAMHS) in the South East of England were assessed for accuracy in the detection of hyperkinetic disorders, using a two-stage process employing the Strengths and Difficulties Questionnaire (SDQ) for screening, with the cut-off between "unlikely" and "possible" as the threshold for identification, and the Development And Well-Being Assessment (DAWBA) as a valid and reliable standard.</p> <p>Results</p> <p>502 cases were collected. Their mean age 11 years (std dev 3 y); 59% were clinically diagnosed as having a hyperkinetic disorder including ADHD. Clinicians had missed two diagnoses of hyperkinesis and six of ADHD. The only 'false positive' case was one that had become asymptomatic on appropriate treatment.</p> <p>Conclusion</p> <p>The identification of children with hyperkinetic disorders by three ordinary English CAMHS teams appears now to be generally consistent with that of a validated, standardised assessment. It seems likely that this reflects the impact of Governmental guidelines, which could therefore be an appropriate tool to ensure consistent accurate diagnosis internationally.</p