1,486 research outputs found
Dynamic splinting for knee flexion contracture following total knee arthroplasty: a case report
Total Knee Arthroplasty operations are increasing in frequency, and knee flexion contracture is a common pathology, both pre-existing and post-operative. A 61-year-old male presented with knee flexion contracture following a total knee arthroplasty. Physical therapy alone did not fully reduce the contracture and dynamic splinting was then prescribed for daily low-load, prolonged-duration stretch. After 28 physical therapy sessions, the active range of motion improved from -20° to -12° (stiff knee still lacking full extension), and after eight additional weeks with nightly wear of dynamic splint, the patient regained full knee extension, (active extension improved from -12° to 0°)
Acoustic Emission from Internal Delamination of a Four-Ply Plate
The basic inverse source problem of acoustic emission is the determination of the nature and location of the internal source from surface measurements of the transient elastic waves generated by the AE event. As pointed out by Sachse [1], this inverse problem requires a knowledge of the dynamic Green’s function for the structure under examination. The evaluation of this dynamic Green’s function is therefore a pivotal problem in the application of the techniques to monitor internal events in engineering structures. This paper deals with the determination of the transient motion of a four-ply fiber composite laminate resulting from an internal impulsive line load acting in the mid-plane of the plate in a direction normal to the mid-plane. The source function for acoustic emission associated with delamination will be located at one or other of the interfaces between the plies and the results presented here complement those of the earlier paper [2] which deals with an impulsive line load acting on the upper interface. Because of symmetry, the response to a line load at the lower interface may be deduced immediately from this upper interface solution
Acceleration of generalized hypergeometric functions through precise remainder asymptotics
We express the asymptotics of the remainders of the partial sums {s_n} of the
generalized hypergeometric function q+1_F_q through an inverse power series z^n
n^l \sum_k c_k/n^k, where the exponent l and the asymptotic coefficients {c_k}
may be recursively computed to any desired order from the hypergeometric
parameters and argument. From this we derive a new series acceleration
technique that can be applied to any such function, even with complex
parameters and at the branch point z=1. For moderate parameters (up to
approximately ten) a C implementation at fixed precision is very effective at
computing these functions; for larger parameters an implementation in higher
than machine precision would be needed. Even for larger parameters, however,
our C implementation is able to correctly determine whether or not it has
converged; and when it converges, its estimate of its error is accurate.Comment: 36 pages, 6 figures, LaTeX2e. Fixed sign error in Eq. (2.28), added
several references, added comparison to other methods, and added discussion
of recursion stabilit
Structural Requirements for Dihydrobenzoxazepinone Anthelmintics: Actions against Medically Important and Model Parasites: Trichuris muris, Brugia malayi, Heligmosomoides polygyrus, and Schistosoma mansoni.
Nine hundred million people are infected with the soil-transmitted helminths Ascaris lumbricoides (roundworm), hookworm, and Trichuris trichiura (whipworm). However, low single-dose cure rates of the benzimidazole drugs, the mainstay of preventative chemotherapy for whipworm, together with parasite drug resistance, mean that current approaches may not be able to eliminate morbidity from trichuriasis. We are seeking to develop new anthelmintic drugs specifically with activity against whipworm as a priority and previously identified a hit series of dihydrobenzoxazepinone (DHB) compounds that block motility of ex vivo Trichuris muris. Here, we report a systematic investigation of the structure-activity relationship of the anthelmintic activity of DHB compounds. We synthesized 47 analogues, which allowed us to define features of the molecules essential for anthelmintic action as well as broadening the chemotype by identification of dihydrobenzoquinolinones (DBQs) with anthelmintic activity. We investigated the activity of these compounds against other parasitic nematodes, identifying DHB compounds with activity against Brugia malayi and Heligmosomoides polygyrus. We also demonstrated activity of DHB compounds against the trematode Schistosoma mansoni, a parasite that causes schistosomiasis. These results demonstrate the potential of DHB and DBQ compounds for further development as broad-spectrum anthelmintics
Stability in Ecosystem Functioning across a Climatic Threshold and Contrasting Forest Regimes
Classical ecological theory predicts that changes in the availability of essential resources such as nitrogen should lead to changes in plant community composition due to differences in species-specific nutrient requirements. What remains unknown, however, is the extent to which climate change will alter the relationship between plant communities and the nitrogen cycle. During intervals of climate change, do changes in nitrogen cycling lead to vegetation change or do changes in community composition alter the nitrogen dynamics? We used long-term ecological data to determine the role of nitrogen availability in changes of forest species composition under a rapidly changing climate during the early Holocene (16k to 8k cal. yrs. BP). A statistical computational analysis of ecological data spanning 8,000 years showed that secondary succession from a coniferous to deciduous forest occurred independently of changes in the nitrogen cycle. As oak replaced pine under a warming climate, nitrogen cycling rates increased. Interestingly, the mechanism by which the species interacted with nitrogen remained stable across this threshold change in climate and in the dominant tree species. This suggests that changes in tree population density over successional time scales are not driven by nitrogen availability. Thus, current models of forest succession that incorporate the effects of available nitrogen may be over-estimating tree population responses to changes in this resource, which may result in biased predictions of future forest dynamics under climate warming
Generation and characterisation of Friedreich ataxia YG8R mouse fibroblast and neural stem cell models
This article has been made available through the Brunel Open Access Publishing Fund.Background: Friedreich ataxia (FRDA) is an autosomal recessive neurodegenerative disease caused by GAA repeat expansion in the first intron of the FXN gene, which encodes frataxin, an essential mitochondrial protein. To further characterise the molecular abnormalities associated with FRDA pathogenesis and to hasten drug screening, the development and use of animal and cellular models is considered essential. Studies of lower organisms have already contributed to understanding FRDA disease pathology, but mammalian cells are more related to FRDA patient cells in physiological terms. Methodology/Principal Findings: We have generated fibroblast cells and neural stem cells (NSCs) from control Y47R mice (9 GAA repeats) and GAA repeat expansion YG8R mice (190+120 GAA repeats). We then differentiated the NSCs in to neurons, oligodendrocytes and astrocytes as confirmed by immunocytochemical analysis of cell specific markers. The three YG8R mouse cell types (fibroblasts, NSCs and differentiated NSCs) exhibit GAA repeat stability, together with reduced expression of frataxin and reduced aconitase activity compared to control Y47R cells. Furthermore, YG8R cells also show increased sensitivity to oxidative stress and downregulation of Pgc-1α and antioxidant gene expression levels, especially Sod2. We also analysed various DNA mismatch repair (MMR) gene expression levels and found that YG8R cells displayed significant reduction in expression of several MMR genes, which may contribute to the GAA repeat stability. Conclusions/Significance: We describe the first fibroblast and NSC models from YG8R FRDA mice and we confirm that the NSCs can be differentiated into neurons and glia. These novel FRDA mouse cell models, which exhibit a FRDA-like cellular and molecular phenotype, will be valuable resources to further study FRDA molecular pathogenesis. They will also provide very useful tools for preclinical testing of frataxin-increasing compounds for FRDA drug therapy, for gene therapy, and as a source of cells for cell therapy testing in FRDA mice. © 2014 Sandi et al
Physical Properties of Wolf-Rayet Stars
The striking broad emission line spectroscopic appearance of Wolf-Rayet (WR)
stars has long defied analysis, due to the extreme physical conditions within
their line and continuum forming regions. Recently, model atmosphere studies
have advanced sufficiently to enable the determination of stellar temperatures,
luminosities, abundances, ionizing fluxes and wind properties. The observed
distributions of nitrogen (WN) and carbon (WC) sequence WR stars in the Milky
Way and in nearby star forming galaxies are discussed; these imply lower limits
to progenitor masses of ~25, 40, 75 Msun for hydrogen-depleted (He-burning) WN,
WC, and H-rich (H-burning) WN stars, respectively. WR stars in massive star
binaries permit studies of wind-wind interactions and dust formation in WC
systems. They also show that WR stars have typical masses of 10-25 Msun,
extending up to 80 Msun for H-rich WN stars. Theoretical and observational
evidence that WR winds depend on metallicity is presented, with implications
for evolutionary models, ionizing fluxes, and the role of WR stars within the
context of core-collapse supernovae and long-duration gamma ray bursts.Comment: 76 pages, 8 figures. Minor revision to "Annual Review of Astronomy &
Astrophysics" review article Volume 45 (2007) following editors comments.
Version with full resolution figures is available from
ftp://astro1.shef.ac.uk/pub/pac/AnnRev_revised.pd
Concentration Change and Countervailing Power in the U.S. Food Manufacturing Industries
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