1,001 research outputs found
Analysis of hip joint loading during walking with different shoe types using instrumented total hip prostheses
Hip joint loads need careful consideration during postoperative physiotherapy after joint replacement. One factor influencing joint loads is the choice of footwear, but it remains unclear which footwear is favorable. The objective of the present study was to investigate the influence of footwear on hip joint loads in vivo. Instrumented hip endoprostheses were used for in vivo load measurements. The parameters resultant contact force (F-res), bending moment (M-bend) and torsional moment (M-tors) were evaluated during treadmill walking at 4 km/h with different shoe types. In general, footwear tended to increase hip joint loading, with the barefoot shoe having the least influence. F-res and M-bend were significantly increased during heel strike for all shoe types in comparison to barefoot walking, with everyday shoe (34.6%; p=0.028 and 47%; p=0.028, respectively) and men's shoe (33.2%; p=0.043 and 41.1%; p=0.043, respectively) resulting in the highest changes. M-tors at AbsMax was increased by all shoes except for the barefoot shoe, with the highest changes for men's shoe (+17.6%, p=0.043) and the shoe with stiffened sole (+17.5%, p=0.08). Shoes, especially those with stiff soles or elaborate cuishing and guiding elements, increase hip joint loads during walking. The influence on peak loads is higher for M-tors than for F-res and M-bend. For patients in which a reduction of hip joints loads is desired, e.g. during physiotherapy after recent surgery or to alleviate symptoms of osteoarthritis, low profile shoes with a flexible sole may be preferred over shoes with a stiff sole or elaborate cushioning elements
Broadband multi-wavelength campaign on PKS 2005-489
The spectral energy distribution (SED) of high-frequency peaked BL Lac
objects (HBL) is characterized by two peaks: one in the UV-X-ray and one in the
GeV-TeV regime. An interesting object for analyzing these broadband
characteristics is PKS 2005-489, which in 2004 showed the softest TeV spectrum
ever measured. In 2009, a multi-wavelength campaign has been conducted with,
for the first time, simultaneous observations by H.E.S.S. (TeV), Fermi/LAT
(GeV), RXTE (keV), Swift (keV, UV, optical) and ATOM (optical) to cover the two
peaks of the SED. During this campaign PKS 2005-489 underwent a high state in
all wavebands which gives the opportunity to study in detail the emission
processes of a high state of this interesting HBL.Comment: 2009 Fermi Symposium; eConf Proceedings C09112
Indirect search for Dark Matter with H.E.S.S
Observations of the Galactic center region with the H.E.S.S. telescopes have
established the existence of a steady, extended source of gamma-ray emission
coinciding with the position of the super massive black hole Sgr A*. This is a
remarkable finding given the expected presence of dense self-annihilating Dark
Matter in the Galactic center region. The self-annihilation process is giving
rise to gamma-ray production through hadronization including the production of
neutral pions which decay into gamma-rays but also through (loop-suppressed)
annihilation into final states of almost mono-energetic photons. We study the
observed gamma-ray signal (spectrum and shape) from the Galactic center in the
context of Dark Matter annihilation and indicate the prospects for further
indirect Dark matter searches with H.E.S.S.Comment: 9 pages, 3 figures. Accepted for Publication in Advances is Space
Research, COSPAR meeting Beijing (2006
A new method of reconstructing very-high-energy gamma-ray spectra: the Template Background Spectrum
Very-high-energy (VHE, E>0.1 TeV) gamma-ray emission regions with angular
extents comparable to the field-of-view of current imaging air-Cherenkov
telescopes (IACT) require additional observations of source-free regions to
estimate the background contribution to the energy spectrum. This reduces the
effective observation time and deteriorates the sensitivity. A new method of
reconstructing spectra from IACT data without the need of additional
observations of source-free regions is developed. Its application is not
restricted to any specific IACT or data format. On the basis of the template
background method, which defines the background in air-shower parameter space,
a new spectral reconstruction method from IACT data is developed and studied,
the Template Background Spectrum (TBS); TBS is tested on published H.E.S.S.
data and H.E.S.S. results. Good agreement is found between VHE gamma-ray
spectra reported by the H.E.S.S. collaboration and those re-analysed with TBS.
This includes analyses of point-like sources, sources in crowded regions, and
of very extended sources down to sources with fluxes of a few percent of the
Crab Nebula flux and excess-to-background ratios around 0.1. However, the TBS
background normalisation introduces new statistical and systematic errors which
are accounted for, but may constitute a limiting case for very faint extended
sources. The TBS method enables the spectral reconstruction of data when other
methods are hampered or even fail. It does not need dedicated observations of
VHE gamma-ray-free regions (e.g. as the On/Off background does) and circumvents
known geometrical limitations to which other methods (e.g. the reflected-region
background) for reconstructing spectral information of VHE gamma-ray emission
regions are prone to; TBS would be, in specific cases, the only feasible way to
reconstruct energy spectra.Comment: 18 pages, accepted for publication (Astronomy and Astrophysics
Locating the VHE source in the Galactic Centre with milli-arcsecond accuracy
Very high-energy gamma-rays (VHE; E>100 GeV) have been detected from the
direction of the Galactic Centre up to energies E>10 TeV. Up to now, the origin
of this emission is unknown due to the limited positional accuracy of the
observing instruments. One of the counterpart candidates is the super-massive
black hole (SMBH) Sgr A*. If the VHE emission is produced within ~10^{15} cm
~1000 r_G (r_G=G M/c^2 is the Schwarzschild radius) of the SMBH, a decrease of
the VHE photon flux in the energy range 100--300 GeV is expected whenever an
early type or giant star approaches the line of sight within ~ milli-arcseconds
(mas). The dimming of the flux is due to absorption by pair-production of the
VHE photons in the soft photon field of the star, an effect we refer to as
pair-production eclipse (PPE). Based upon the currently known orbits of stars
in the inner arcsecond of the Galaxy we find that PPEs lead to a systematic
dimming in the 100--300 GeV band at the level of a few per cent and lasts for
several weeks. Since the PPE affects only a narrow energy band and is well
correlated with the passage of the star, it can be clearly discriminated
against other systematic or even source-intrinsic effects. While the effect is
too small to be observable with the current generation of VHE detectors,
upcoming high count-rate experiments like the Cherenkov telescope array (CTA)
will be sufficiently sensitive. Measuring the temporal signature of the PPE
bears the potential to locate the position and size of the VHE emitting region
within the inner 1000 r_G or in the case of a non-detection exclude the
immediate environment of the SMBH as the site of gamma-ray production
altogether.Comment: 7 pages, published in MNRAS 402, pg. 1342-134
TSH-CHECK-1 test: diagnostic accuracy and potential application to initiating treatment for hypothyroidism in patients on anti-tuberculosis drugs.
Thyroid-stimulating hormone (TSH) promotes expression of thyroid hormones which are essential for metabolism, growth, and development. Second-line drugs to treat tuberculosis (TB) can cause hypothyroidism by suppressing thyroid hormone synthesis. Therefore, TSH levels are routinely measured in TB patients receiving second-line drugs, and thyroxin treatment is initiated where indicated. However, standard TSH tests are technically demanding for many low-resource settings where TB is prevalent; a simple and inexpensive test is urgently needed
Identification and functional characterisation of a locus for target site integration in Fusarium graminearum
Background
Fusarium Head Blight (FHB) is a destructive floral disease of different cereal crops. The Ascomycete fungus Fusarium graminearum (Fg) is one of the main causal agents of FHB in wheat and barley. The role(s) in virulence of Fg genes include genetic studies that involve the transformation of the fungus with different expression cassettes. We have observed in several studies where Fg genes functions were characterised that integration of expression cassettes occurred randomly. Random insertion of a cassette may disrupt gene expression and/or protein functions and hence the overall conclusion of the study. Target site integration (TSI) is an approach that consists of identifying a chromosomal region where the cassette can be inserted. The identification of a suitable locus for TSI in Fg would avert the potential risks of ectopic integration.
Results
Here, we identified a highly conserved intergenic region on chromosome 1 suitable for TSI. We named this intergenic region TSI locus 1. We developed an efficient cloning vector system based on the Golden Gate method to clone different expression cassettes for use in combination with TSI locus 1. We present evidence that integrations in the TSI locus 1 affects neither fungal virulence nor fungal growth under different stress conditions. Integrations at the TSI locus 1 resulted in the expression of different gene fusions. In addition, the activities of Fg native promoters were not altered by integration into the TSI locus 1. We have developed a bespoke bioinformatic pipeline to analyse the existence of ectopic integrations, cassette truncations and tandem insertions of the cassette that may occurred during the transformation process. Finally, we established a protocol to study protein secretion in wheat coleoptiles using confocal microscopy and the TSI locus 1.
Conclusion
The TSI locus 1 can be used in Fg and potentially other cereal infecting Fusarium species for diverse studies including promoter activity analysis, protein secretion, protein localisation studies and gene complementation. The bespoke bioinformatic pipeline developed in this work together with PCR amplification of the insert could be an alternative to Southern blotting, the gold standard technique used to identify ectopic integrations, cassette truncations and tandem insertions in fungal transformation
Combined pangenomics and transcriptomics reveals core and redundant virulence processes in a rapidly evolving fungal plant pathogen
Background
Studying genomic variation in rapidly evolving pathogens potentially enables identification of genes supporting their “core biology”, being present, functional and expressed by all strains or “flexible biology”, varying between strains. Genes supporting flexible biology may be considered to be “accessory”, whilst the “core” gene set is likely to be important for common features of a pathogen species biology, including virulence on all host genotypes. The wheat-pathogenic fungus Zymoseptoria tritici represents one of the most rapidly evolving threats to global food security and was the focus of this study.
Results
We constructed a pangenome of 18 European field isolates, with 12 also subjected to RNAseq transcription profiling during infection. Combining this data, we predicted a “core” gene set comprising 9807 sequences which were; (1) present in all isolates; (2) lacking inactivating polymorphisms; and (3) expressed by all isolates. A large accessory genome, consisting of 45% of the total genes was also defined. We classified genetic and genomic polymorphism at both chromosomal and individual gene scales. Proteins required for essential functions including virulence, had lower-than average sequence variability amongst core genes. Both core and accessory genomes encoded many small, secreted candidate effector proteins that likely interact with plant immunity. Viral vector-mediated transient in planta overexpression of 88 candidates failed to identify any which induced leaf necrosis characteristic of disease. However, functional complementation of a non-pathogenic deletion mutant lacking five core genes, demonstrated that full virulence was restored by re-introduction of the single gene exhibiting least sequence polymorphism and highest expression.
Conclusions
These data support the combined use of pangenomics and transcriptomics for defining genes which represent core, and potentially exploitable, weaknesses in rapidly evolving pathogens
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