308 research outputs found

    Developing sexual competence? Exploring strategies for the provision of effective sexualities and relationships education

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    School-based sexualities and relationships education (SRE) offers one of the most promising means of improving young people's sexual health through developing 'sexual competence'. In the absence of evidence on whether the term holds the same meanings for young people and adults (e.g. teachers, researchers, policy-makers), the paper explores 'adult' notions of sexual competence as construed in research data and alluded to in UK Government guidance on SRE, then draws on empirical research with young people on factors that affect the contexts, motivations and outcomes of sexual encounters, and therefore have implications for sexual competence. These data from young people also challenge more traditional approaches to sexualities education in highlighting disjunctions between the content of school-based input and their reported sexual experience. The paper concludes by considering the implications of these insights for developing a shared notion of what SRE is trying to achieve and suggestions for recognition in the content and approaches to SRE.</p

    Rapid Aeroelastic Analysis of Blade Flutter in Turbomachines

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    The LINFLUX-AE computer code predicts flutter and forced responses of blades and vanes in turbomachines under subsonic, transonic, and supersonic flow conditions. The code solves the Euler equations of unsteady flow in a blade passage under the assumption that the blades vibrate harmonically at small amplitudes. The steady-state nonlinear Euler equations are solved by a separate program, then equations for unsteady flow components are obtained through linearization around the steady-state solution. A structural-dynamics analysis (see figure) is performed to determine the frequencies and mode shapes of blade vibrations, a preprocessor interpolates mode shapes from the structural-dynamics mesh onto the LINFLUX computational-fluid-dynamics mesh, and an interface code is used to convert the steady-state flow solution to a form required by LINFLUX. Then LINFLUX solves the linearized equations in the frequency domain to calculate the unsteady aerodynamic pressure distribution for a given vibration mode, frequency, and interblade phase angle. A post-processor uses the unsteady pressures to calculate generalized aerodynamic forces, response amplitudes, and eigenvalues (which determine the flutter frequency and damping). In comparison with the TURBO-AE aeroelastic-analysis code, which solves the equations in the time domain, LINFLUX-AE is 6 to 7 times faster

    A novel hyperekplexia-causing mutation in the pre-transmembrane segment 1 of the human glycine receptor alpha1 subunit reduces membrane expression and impairs gating by agonists

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    In this study, we have compared the functional consequences of three mutations (R218Q, V260M, and Q266H) in the 1 subunit of the glycine receptor (GlyRA1) causing hyperekplexia, an inherited neurological channelopathy. In HEK-293 cells, the agonist EC50s for glycine- activated Cl currents were increased from 26 M in wtGlyRA1, to 5747, 135, and 129 M in R218Q, V260M, and Q266H GlyRA1 channels, respectively. Cl currents elicited by -alanine and taurine, which behave as agonists at wtGlyRA1, were decreased in V260M and Q266H mutant receptors and virtually abolished in GlyRA1 R218Q receptors. Gly-gated Cl currents were similarly antagonized by low concentrations of strychnine in both wild-type (wt) and R218Q GlyRA1 channels, suggesting that the Arg-218 residue plays a crucial role in GlyRA1 channel gating, with only minor effects on the agonist/ antagonist binding site, a hypothesis supported by our molecular model of the GlyRA1 subunit. The R218Q mutation, but not the V260M or the Q266H mutation, caused a marked decrease of receptor subunit expression both in total cell lysates and in isolated plasma membrane proteins. This decreased expression does not seem to explain the reduced agonist sensitivity of GlyRA1 R218Q channels since no difference in the apparent sensitivity to glycine or taurine was observed when wtGlyRA1 receptors were expressed at levels comparable with those of R218Q mutant receptors. In conclusion, multiple mechanisms may explain the dramatic decrease in GlyR function caused by the R218Q mutation, possibly providing the molecular basis for its association with a more severe clinical phenotype

    Iodopentafluorobenzene: Electronic state spectroscopy by high resolution vacuum ultraviolet photoabsorption and photoelectron spectroscopy

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    The electronic transitions of iodopentafluorobenzene (C6F5I) have been investigated experimentally for the first time by high-resolution photoabsorption spectroscopy in the energy range 3.6 – 10.7 eV. The character of the valence excited states has been discussed taking into account calculations available in the literature. The ionisation energies of the molecule in its electronic ground state have been measured by high-resolution He(I) photoelectron spectroscopy. The energies of the ionic bands are shifted by about 0.5 eV compared to the earliest literature values but they agree with the most recently published measurements. All the spectra presented in this paper represent highest resolution measurements of their kind for iodopentafluorobenzene. The absolute photoabsorption cross sections have been used to model photolysis rates and residence times in the terrestrial atmosphere

    The influence of anesthetics, neurotransmitters and antibiotics on the relaxation processes in lipid membranes

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    In the proximity of melting transitions of artificial and biological membranes fluctuations in enthalpy, area, volume and concentration are enhanced. This results in domain formation, changes of the elastic constants, changes in permeability and slowing down of relaxation processes. In this study we used pressure perturbation calorimetry to investigate the relaxation time scale after a jump into the melting transition regime of artificial lipid membranes. This time corresponds to the characteristic rate of domain growth. The studies were performed on single-component large unilamellar and multilamellar vesicle systems with and without the addition of small molecules such as general anesthetics, neurotransmitters and antibiotics. These drugs interact with membranes and affect melting points and profiles. In all systems we found that heat capacity and relaxation times are related to each other in a simple manner. The maximum relaxation time depends on the cooperativity of the heat capacity profile and decreases with a broadening of the transition. For this reason the influence of a drug on the time scale of domain formation processes can be understood on the basis of their influence on the heat capacity profile. This allows estimations of the time scale of domain formation processes in biological membranes.Comment: 12 pages, 6 figure

    Correction effects of the ScoliOlogiC(® )„Chêneau light" brace in patients with scoliosis

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    BACKGROUND: Different bracing concepts are used today for the treatment of scoliosis. The plaster cast method worldwide seems to be the most practiced technique at the moment. CAD (Computer Aided Design) systems are on the market which allow brace adjustments without plaster. The latest development however, is the use of the ScoliOlogiC™ off the shelf system enabling the orthopaedic technician to construct a light brace for scoliosis correction from a variety of pattern specific shells to be connected to an anterior and a posterior upright. This „Chêneau light" brace, developed according to the Chêneau principle, promises a reduced impediment of quality of life in the brace. However, material reduction should not result in reduced effectiveness. Therefore the primary correction effect in the „Chêneau light" brace has been evaluated and compared with that of other braces used today. METHODS: The correction effects of the first 81 patients (main diagnosis Adolescent Idiopathic Scoliosis (AIS) [n = 64] or Early Onset Scoliosis (EOS) [n = 15]), treated according to the principle of the „Chêneau light" brace were evaluated after an average treatment time of 6 weeks by a full-body X-ray made in the standing position whilst wearing the brace and compared with the last X-ray before bracing. The average curvature angle of the whole group was 35,6°, the average age was 12,9 years (SD 1,9), average Risser sign was 1,3 (SD 1,5), average Tanner rating 2,75 (SD 0,7). RESULTS: The Cobb angle in the whole group was reduced by an average of 16,4°, which corresponds to a correction effect of 51%. The differences were highly significant in the T-test (T = 17,4; p < 0,001). The best correction effects reported in literature so far are about 40% in two different studies. The correction effect was highest in lumbar and thoracolumbar curve pattern (62 %; n = 18). In thoracic scoliosis the correction effect was 36 % (n = 41) and in double major curve pattern 50 % (n = 22). The correction effect correlated slightly negative with age (r = -0,24; p = 0,014), negatively with the Risser stage (-0,29; p = 0,0096) and correlated negatively with the Cobb angle measured before treatment (r = -0,43; p < 0,0001). CONCLUSION: The use of the „Chêneau light" brace leads to correction effects above average when compared to the correction effects of other braces described in literature. The reduction of material seems to affect the desired correction in a positive way

    Phase transitions in biological membranes

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    Native membranes of biological cells display melting transitions of their lipids at a temperature of 10-20 degrees below body temperature. Such transitions can be observed in various bacterial cells, in nerves, in cancer cells, but also in lung surfactant. It seems as if the presence of transitions slightly below physiological temperature is a generic property of most cells. They are important because they influence many physical properties of the membranes. At the transition temperature, membranes display a larger permeability that is accompanied by ion-channel-like phenomena even in the complete absence of proteins. Membranes are softer, which implies that phenomena such as endocytosis and exocytosis are facilitated. Mechanical signal propagation phenomena related to nerve pulses are strongly enhanced. The position of transitions can be affected by changes in temperature, pressure, pH and salt concentration or by the presence of anesthetics. Thus, even at physiological temperature, these transitions are of relevance. There position and thereby the physical properties of the membrane can be controlled by changes in the intensive thermodynamic variables. Here, we review some of the experimental findings and the thermodynamics that describes the control of the membrane function.Comment: 23 pages, 15 figure

    Can osseous landmarks in the distal medial humerus be used to identify the attachment sites of ligaments and tendons: paleopathologic–anatomic imaging study in cadavers

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    Objective: To describe osseous landmarks that allow identification of the attachments of the ligaments and tendons in the distal medial aspect of the humerus. Materials and methods: Reliable osseous landmarks in the distal medial aspect of the humerus were identified in 34 well-preserved specimens from a paleopathologic collection. These osseous landmarks were then sought in magnetic resonance (MR) images of ten cadaveric elbow specimens so that the ease of their visualization and optimal imaging plane could be assessed. To assign these osseous landmarks to specific attachments of the tendons and ligaments in the distal medial humerus, we cut the specimens in slices and photographed and examined them. Subsequently, the prevalence of these osseous landmarks as well as the attachment sites of the tendons and ligaments in this location was determined. Results: We determined ten reliable osseous landmarks in the distal medial aspect of the humerus, their prevalence and ease of identification, and their relationship to the attachments of the tendons and ligaments at the medial distal humerus. Conclusion: It is possible to use osseous landmarks at the distal medial humerus to facilitate identification of the different attachments of tendons and ligaments when MR images of the elbow are assesse
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