2,839 research outputs found

    Cell wall microstructure, pore size distribution and absolute density of hemp shiv

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    This paper, for the first time, fully characterizes the intrinsic physical parameters of hemp shiv including cell wall microstructure, pore size distribution and absolute density. Scanning electron microscopy revealed microstructural features similar to hardwoods. Confocal microscopy revealed three major layers in the cell wall: middle lamella, primary cell wall and secondary cell wall. Computed tomography improved the visualization of pore shape and pore connectivity in three dimensions. Mercury intrusion porosimetry (MIP) showed that the average accessible porosity was 76.67 ± 2.03% and pore size classes could be distinguished into micropores (3–10 nm) and macropores (0.1–1 µm and 20–80 µm). The absolute density was evaluated by helium pycnometry, MIP and Archimedes’ methods. The results show that these methods can lead to misinterpretation of absolute density. The MIP method showed a realistic absolute density (1.45 g cm−3) consistent with the density of the known constituents, including lignin, cellulose and hemi-cellulose. However, helium pycnometry and Archimedes’ methods gave falsely low values owing to 10% of the volume being inaccessible pores, which require sample pretreatment in order to be filled by liquid or gas. This indicates that the determination of the cell wall density is strongly dependent on sample geometry and preparation

    Facility for fast neutron irradiation tests of electronics at the ISIS spallation neutron source

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    The VESUVIO beam line at the ISIS spallation neutron source was set up for neutron irradiation tests in the neutron energy range above 10 MeV. The neutron flux and energy spectrum were shown, in benchmark activation measurements, to provide a neutron spectrum similar to the ambient one at sea level, but with an enhancement in intensity of a factor of 107. Such conditions are suitable for accelerated testing of electronic components, as was demonstrated here by measurements of soft error rates in recent technology field programable gate arrays

    Physical characterisation of hemp shiv: Cell wall structure and porosity

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    Hemp shiv has been widely used as a plant aggregate incorporated into natural building composites such as hemp-lime due to its low thermal conductivity and high moisture buffer value. The aim of this research is to study the intrinsic physical parameters such as the porosity and cell wall structure of hemp shiv, which are responsible for the favourable thermal and hygric properties of hemp shiv. Scanning electron microscope observations of hemp shiv revealed microstructural features. A computed tomography (CT) scan improved the vizualization of pore shape and pore connectivity in three dimensions. The vessels exhibit little variation in size and there is no clear pore arrangement with a diffuse-porous distribution. The vessels are mostly solitary although some small groups of adjacent vessels exhibit shared cell walls between them. The vessels are approximately 50 to 100 μm in diameter and are surrounded by relatively thick fibre cells. These thick-walled fibres are located between the vessels with a diameter ranging from 1μm to 2μm. The pore frequency of hemp shiv (generally only measured on diffuse-porous woods) is around 20.8 vessels/mm2. The porosity of hemp shiv has been studied by a combination of mercury intrusion porosimetry (MIP) and CT scanning. Average accessible porosity of hemp shiv is 76.67 ± 2.03 % measured by MIP measurement and from 50% to 75% measured by CT, depending on the threshold and resolution

    Interpersonal functioning in obsessive-compulsive personality disorder

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    The core symptoms of obsessive-compulsive personality disorder (OCPD) often lead to interpersonal difficulties. However, little research has explored interpersonal functioning in OCPD. This study examined interpersonal problems, interpersonal sensitivities, empathy, and systemizing, the drive to analyze and derive underlying rules for systems, in a sample of 25 OCPD individuals, 25 individuals with comorbid OCPD and obsessive-compulsive disorder (OCD), and 25 healthy controls. We found that OCPD individuals reported hostile-dominant interpersonal problems and sensitivities with warm-dominant behavior by others, whereas OCPD+OCD individuals reported submissive interpersonal problems and sensitivities with warm-submissive behavior by others. Individuals with OCPD, with and without OCD, reported less empathic perspective taking relative to healthy controls. Finally, we found that OCPD males reported a higher drive to analyze and derive rules for systems than OCPD females. Overall, results suggest that there are interpersonal deficits associated with OCPD and the clinical implications of these deficits are discussed

    A statistical analysis of murine incisional and excisional acute wound models

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    YesMice represent the most commonly used species for preclinical in vivo research. While incisional and excisional acute murine wound models are both frequently employed, there is little agreement on which model is optimum. Moreover, current lack of standardization of wounding procedure, analysis time point(s), method of assessment, and the use of individual wounds vs. individual animals as replicates makes it difficult to compare across studies. Here we have profiled secondary intention healing of incisional and excisional wounds within the same animal, assessing multiple parameters to determine the optimal methodology for future studies. We report that histology provides the least variable assessment of healing. Furthermore, histology alone (not planimetry) is able to detect accelerated healing in a castrated mouse model. Perhaps most importantly, we find virtually no correlation between wounds within the same animal, suggesting that use of wound (not animal) biological replicates is perfectly acceptable. Overall, these findings should guide and refine future studies, increasing the likelihood of detecting novel phenotypes while reducing the numbers of animals required for experimentation

    The B7 Homologues and their Receptors in Hematologic Malignancies

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    The B7 homologues and their receptors regulate both peripheral tolerance and adaptive immunity. This field is rapidly evolving as new ligands and receptors are being identified. Much of the work supporting their role in the regulation of host anti‐tumor immunity has been derived from experimental models and clinical trials in solid malignancies. However, a growing body of evidence demonstrates that the B7‐H family has important immunologic and non‐immunologic functions in a variety of hematologic malignancies. Herein, we will review recent evidence that supports the therapeutic targeting of the B7 homologues in hematologic malignancies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91338/1/ejh1766.pd

    Embodied learning: Responding to AIDS in Lesotho's education sector

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    This is an Author's Accepted Manuscript of an article published in Children's Geographies, 7(1), 2009. Copyright @ 2009 Taylor & Francis, available online at: http://www.tandfonline.com/doi/abs/10.1080/14733280802630981.In contrast to pre-colonial practices, education in Lesotho's formal school system has historically assumed a Cartesian separation of mind and body, the disciplining of students' bodies serving principally to facilitate cognitive learning. Lesotho has among the highest HIV-prevalence rates worldwide, and AIDS has both direct and indirect impacts on the bodies of many children. Thus, students' bodies can no longer be taken for granted but present a challenge for education. Schools are increasingly seen as a key point of intervention to reduce young people's risk of contracting the disease and also to assist them to cope with its consequences: there is growing recognition that such goals require more than cognitive learning. The approaches adopted, however, range from those that posit a linear and causal relationship between knowledge, attitudes and practices (so-called ‘KAP’ approaches, in which the role of schools is principally to inculcate the pre-requisite knowledge) to ‘life skills programmes’ that advocate a more embodied learning practice in schools. Based on interviews with policy-makers and practitioners and a variety of documentary sources, this paper examines a series of school-based AIDS interventions, arguing that they represent a less radical departure from ‘education for the mind’ than might appear to be the case. The paper concludes that most interventions serve to cast on children responsibility for averting a social risk, and to ‘normalise’ aberrant children's bodies to ensure they conform to what the cognitively-oriented education system expects
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