517 research outputs found
Opportunity Lost: Why and How to Improve the HHS-Proposed Legislation Governing Law Enforcement Access to Medical Records
A Feasibility Study in Measuring Soft Tissue Artifacts on the Upper Leg Using Inertial and Magnetic Sensors
Soft-tissue artifacts cause inaccurate estimates of body segment orientations. The inertial sensor (or optical marker) is orientating (or displacing) with respect to the bone it has to measure, due to muscle and skin movement [1]. In this pilot study 11 inertial and magnetic sensors (MTw, Xsens Technologies) were placed on the rectus femoris, vastus medialis and vastus lateralis (upper leg). One sensor was positioned on the tendon plate behind the quadriceps (iliotibial tract, as used in Xsens MVN [1]) and used as reference sensor. Walking, active and passive knee extensions and muscle contractions without flexion/extension were recorded using one subject. The orientation of each sensor with respect to the reference sensor was calculated. During walking, relative orientations of up to 28.6Âș were measured (22.4±3.6Âș). During muscle contractions without flexion/extension the largest relative orientations were measured on the rectus femoris (up to 11.1Âș) [2]. This pilot showed that the ambulatory measurement of deformation of the upper leg is feasible; however, improving the measurement technology is required. We therefore have designed a new inertial and magnetic sensor system containing smaller sensors, based on the design of an instrumented glove for the assessment of hand kinematics [3]. This new sensor system will then be used to investigate soft-tissue artifacts more accurately; in particular we will focus on in-use estimation and elimination of these artifacts
Relativistic Calculation of the Meson Spectrum: a Fully Covariant Treatment Versus Standard Treatments
A large number of treatments of the meson spectrum have been tried that
consider mesons as quark - anti quark bound states. Recently, we used
relativistic quantum "constraint" mechanics to introduce a fully covariant
treatment defined by two coupled Dirac equations. For field-theoretic
interactions, this procedure functions as a "quantum mechanical transform of
Bethe-Salpeter equation". Here, we test its spectral fits against those
provided by an assortment of models: Wisconsin model, Iowa State model,
Brayshaw model, and the popular semi-relativistic treatment of Godfrey and
Isgur. We find that the fit provided by the two-body Dirac model for the entire
meson spectrum competes with the best fits to partial spectra provided by the
others and does so with the smallest number of interaction functions without
additional cutoff parameters necessary to make other approaches numerically
tractable. We discuss the distinguishing features of our model that may account
for the relative overall success of its fits. Note especially that in our
approach for QCD, the resulting pion mass and associated Goldstone behavior
depend sensitively on the preservation of relativistic couplings that are
crucial for its success when solved nonperturbatively for the analogous
two-body bound-states of QED.Comment: 75 pages, 6 figures, revised content
Abundance and dynamics of filamentous fungi in the complex ambrosia gardens of the primitively eusocial beetle Xyleborinus saxeseniiRatzeburg (Coleoptera: Curculionidae, Scolytinae)
Insect fungus gardens consist of a community of interacting microorganisms that can have either beneficial or detrimental effects to the farmers. In contrast to fungus-farming ants and termites, the fungal communities of ambrosia beetles and the effects of particular fungal species on the farmers are largely unknown. Here, we used a laboratory rearing technique for studying the filamentous fungal garden community of the ambrosia beetle, Xyleborinus saxesenii, which cultivates fungi in tunnels excavated within dead trees. Raffaelea sulfurea and Fusicolla acetilerea were transmitted in spore-carrying organs by gallery founding females and established first in new gardens. Raffaelea sulfurea had positive effects on egg-laying and larval numbers. Over time, four other fungal species emerged in the gardens. Prevalence of one of them, Paecilomyces variotii, correlated negatively with larval numbers and can be harmful to adults by forming biofilms on their bodies. It also comprised the main portion of garden material removed from galleries by adults. Our data suggest that two mutualistic, several commensalistic and one to two pathogenic filamentous fungi are associated with X. saxesenii. Fungal diversity in gardens of ambrosia beetles appears to be much lower than that in gardens of fungus-culturing ants, which seems to result from essential differences in substrates and behaviour
The effects of oxygen concentration on cell death, anti-oxidant transcription, acute inflammation, and cell proliferation in precision-cut lung slices
Although animal models are often used in drug research, alternative experimental models are becoming more popular as they reduce animal use and suffering. Of particular interest are precision-cut lung slices, which refer to explants - with a reproducible thickness and diameter - that can be cultured ex vivo. Because lung slices (partially) reflect functional and structural features of whole tissue, they are often applied in the field of immunology, pharmacology, toxicology, and virology. Nevertheless, previous research failed to adequately address concerns with respect to the viability of lung slices. For instance, the effect of oxygen concentration on lung slice viability has never been thoroughly investigated. Therefore, the main goal of this study was to investigate the effect of oxygen concentration (20 vs. 80% O-2) on the degree of cell death, anti-oxidant transcription, acute inflammation, and cell proliferation in lung slices. According to the results, slices incubated at 20% O-2 displayed less cell death, antioxidant transcription, and acute inflammation, as well as more cell proliferation, demonstrating that these slices were considerably more viable than slices cultured at 80% O-2. These findings expand our knowledge on lung slices and their use as an alternative experimental model in drug research
Multiple GF-1 binding sites flank the erythroid specific transcription unit of the human carbonic anhydrase I gene
AbstractSix potential GF-1 sites which bind an erythroid factor are present in the 5' and 3' regions flanking the erythroid-speciflc transcription unit of the human carbonic anhydrase 1 (HCAI) gene. When two of these sites are placed upstream of a minimal eukaryotic promoter they confer upregulated expression in erythroid over non-erythroid cells. The presence of the erythroid factor in TPA-treated HEL cells in which the level of HCAI transcript has greatly decreased and in non-HCAI-expressing K562 cells suggests that in these cases the presence of the factor is not sufficient for HCAI expression
Biodegradable microspheres for the sustained release of PDGF-receptor directed PPB-HSA targeted to the fibrotic kidney
Biodegradable microspheres for the sustained release of PDGF-receptor directed PPB-HSA targeted to the fibrotic kidney
Biodegradable microspheres for the sustained release of PDGF-receptor directed PPB-HSA targeted to the fibrotic kidney
Allelic imbalance of 7q32.3-q36.1 during tumorigenesis in Barrett's esophagus
Malignant transformation of Barrett's esophagus is characterized by three
distinct premalignant stages: intestinal metaplasia (MET), low- (LGD), and
high-grade dysplasia (HGD). We reported recently an increase in the
frequency of loss of 7q33-q35 between LGD and HGD as determined by
comparative genomic hybridization (P. H. J. Riegman et al., Cancer Res.,
61: 3164-3170, 2001). Now the 7q32.3-q36.1 region was additionally
characterized by allelotype analysis with 11 polymorphic markers in 15
METs, 20 LGDs, 20 HGDs, and 20 Barrett's adenocarcinomas from different
patients. Low percentages of imbalance were determined in METs and LGDs,
7% and 10%, respectively, whereas HGDs and Barrett's adenocarcinomas
revealed high percentages of loss, 75% and 65%, respectively. This
difference in frequency between LGDs and HGDs appeared highly significant:
P = 0.00007. The majority of imbalances were found at D7S2439 and D7S483,
located on 7q36.1. These data suggest that markers from this area can be
used as a diagnostic tool in Barrett's esophagus, i.e., to distinguish
between watchful waiting and active treatment
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