1,754 research outputs found
Flow characteristics of carbon fibre moulding compounds
This paper presents the development of a low-cost carbon fibre moulding compound using an automated spray deposition process. Directed Fibre Compounding (DFC) is used to produce charge packs directly from low cost carbon fibre tows and liquid epoxy resin. A range of material and process related parameters have been studied to understand their influence on the level of macroscopic charge flow, in an attempt to produce a carbon fibre moulding compound with similar flow characteristics to conventional glass fibre SMCs.
Charge packs covering just 40% of the mould can be effectively used to process DFC, without detrimentally affecting void content, fibre distribution and mechanical properties. Tensile stiffness and strength values of 36GPa and 320MPa are reported for isotropic materials (100% charge coverage), which increase to 46GPa and 408MPa with flow induced alignment (50% charge coverage) at 50% fibre volume fraction
Asymptotic Capture-Number and Island-Size Distributions for One-Dimensional Irreversible Submonolayer Growth
Using a set of evolution equations [J.G. Amar {\it et al}, Phys. Rev. Lett.
{\bf 86}, 3092 (2001)] for the average gap-size between islands, we calculate
analytically the asymptotic scaled capture-number distribution (CND) for
one-dimensional irreversible submonolayer growth of point islands. The
predicted asymptotic CND is in reasonably good agreement with kinetic
Monte-Carlo (KMC) results and leads to a \textit{non-divergent asymptotic}
scaled island-size distribution (ISD). We then show that a slight modification
of our analytical form leads to an analytic expression for the asymptotic CND
and a resulting asymptotic ISD which are in excellent agreement with KMC
simulations. We also show that in the asymptotic limit the self-averaging
property of the capture zones holds exactly while the asymptotic scaled gap
distribution is equal to the scaled CND.Comment: 4 pages, 1 figure, submitted to Phys. Rev.
ARQ-197, a small-molecule inhibitor of c-Met, reduces tumour burden and prevents myeloma-induced bone disease in vivo
The receptor tyrosine kinase c-Met, its ligand HGF, and components of the downstream signalling pathway, have all been implicated in the pathogenesis of myeloma, both as modulators of plasma cell proliferation and as agents driving osteoclast differentiation and osteoblast inhibition thus, all these contribute substantially to the bone destruction typically caused by myeloma. Patients with elevated levels of HGF have a poor prognosis, therefore, targeting these entities in such patients may be of substantial benefit. We hypothesized that ARQ-197 (Tivantinib), a small molecule c-Met inhibitor, would reduce myeloma cell growth and prevent myeloma-associated bone disease in a murine model. In vitro we assessed the effects of ARQ-197 on myeloma cell proliferation, cytotoxicity and c-Met protein expression in human myeloma cell lines. In vivo we injected NOD/SCID-γ mice with PBS (non-tumour bearing) or JJN3 cells and treated them with either ARQ-197 or vehicle. In vitro exposure of JJN3, U266 or NCI-H929 cells to ARQ-197 resulted in a significant inhibition of cell proliferation and an induction of cell death by necrosis, probably caused by significantly reduced levels of phosphorylated c-Met. In vivo ARQ-197 treatment of JJN3 tumour-bearing mice resulted in a significant reduction in tumour burden, tumour cell proliferation, bone lesion number, trabecular bone loss and prevented significant decreases in the bone formation rate on the cortico-endosteal bone surface compared to the vehicle group. However, no significant differences on bone parameters were observed in non-tumour mice treated with ARQ-197 compared to vehicle, implying that in tumour-bearing mice the effects of ARQ-197 on bone cells was indirect. In summary, these res ults suggest that ARQ-197 could be a promising therapeutic in myeloma patients, leading to both a reduction in tumour burden and an inhibition of myeloma-induced bone disease
Ordering dynamics of the driven lattice gas model
The evolution of a two-dimensional driven lattice-gas model is studied on an
L_x X L_y lattice. Scaling arguments and extensive numerical simulations are
used to show that starting from random initial configuration the model evolves
via two stages: (a) an early stage in which alternating stripes of particles
and vacancies are formed along the direction y of the driving field, and (b) a
stripe coarsening stage, in which the number of stripes is reduced and their
average width increases. The number of stripes formed at the end of the first
stage is shown to be a function of L_x/L_y^\phi, with \phi ~ 0.2. Thus,
depending on this parameter, the resulting state could be either single or
multi striped. In the second, stripe coarsening stage, the coarsening time is
found to be proportional to L_y, becoming infinitely long in the thermodynamic
limit. This implies that the multi striped state is thermodynamically stable.
The results put previous studies of the model in a more general framework
NOD/SCID-GAMMA Mice Are an Ideal Strain to Assess the Efficacy of Therapeutic Agents Used in the Treatment of Myeloma Bone Disease
Animal models of multiple myeloma vary in terms of consistency of onset, degree of tumour burden and degree of myeloma bone disease. Here we describe five pre-clinical models of myeloma in NOD/SCID-GAMMA mice to specifically study the effects of therapeutic agents on myeloma bone disease. Groups of 7–8 week old female irradiated NOD/SCID-GAMMA mice were injected intravenously via the tail vein with either 1x106 JJN3, U266, XG-1 or OPM-2 human myeloma cell lines or patient-derived myeloma cells. At the first signs of morbidity in each tumour group all animals were sacrificed. Tumour load was measured by histological analysis, and bone disease was assessed by micro-CT and standard histomorphometric methods. Mice injected with JJN3, U266 or OPM-2 cells showed high tumour bone marrow infiltration of the long bones with low variability, resulting in osteolytic lesions. In contrast, mice injected with XG-1 or patient-derived myeloma cells showed lower tumour bone marrow infiltration and less bone disease with high variability. Injection of JJN3 cells into NOD/SCID-GAMMA mice resulted in an aggressive, short-term model of myeloma with mice exhibiting signs of morbidity 3 weeks later. Treating these mice with zoledronic acid at the time of tumour cell injection or once tumour was established prevented JJN3-induced bone disease but did not reduce tumour burden, whereas, carfilzomib treatment given once tumour was established significantly reduced tumour burden. Injection of U266, XG-1, OPM-2 and patient-derived myeloma cells resulted in less aggressive longer-term models of myeloma with mice exhibiting signs of morbidity 8 weeks later. Treating U266-induced disease with zoledronic acid prevented the formation of osteolytic lesions and trabecular bone loss as well as reducing tumour burden whereas, carfilzomib treatment only reduced tumour burden. In summary, JJN3, U266 or OPM-2 cells injected into NOD/SCID-GAMMA mice provide robust models to study anti-myeloma therapies, particularly those targeting myeloma bone disease
Paleomagnetic evidence for modern-like plate motion velocities at 3.2 Ga
The mode and rates of tectonic processes and lithospheric growth during the Archean [4.0 to 2.5 billion years (Ga) ago] are subjects of considerable debate. Paleomagnetism may contribute to the discussion by quantifying past plate velocities. We report a paleomagnetic pole for the ~3180 million year (Ma) old Honeyeater Basalt of the East Pilbara Craton, Western Australia, supported by a positive fold test and micromagnetic imaging. Comparison of the 44°±15° Honeyeater Basalt paleolatitude with previously reported paleolatitudes requires that the average latitudinal drift rate of the East Pilbara was ≥2.5 cm/year during the ~170 Ma preceding 3180 Ma ago, a velocity comparable with those of modern plates. This result is the earliest unambiguous evidence yet uncovered for long-range lithospheric motion. Assuming this motion is due primarily to plate motion instead of true polar wander, the result is consistent with uniformitarian or episodic tectonic processes in place by 3.2 Ga ago
How do cities approach policy innovation and policy learning? A study of 30 policies in Northern Europe and North America
This paper reports on a study of current practice in policy transfer, and ways in which its effectiveness can be increased. A literature review identifies important factors in examining the transfer of policies. Results of interviews in eleven cities in Northern Europe and North America investigate these factors further. The principal motivations for policy transfer were strategic need and curiosity. Local officials and politicians dominated the process of initiating policy transfer, and local officials were also the leading players in transferring experience. A range of information sources are used in the search process but human interaction was the most important source of learning for two main reasons. First, there is too much information available through the Internet and the search techniques are not seen to be wholly effective in identifying the necessary information. Secondly, the information available on websites, portals and even good practice guides is not seen to be of mixed quality with risks of focussing only on successful implementation and therefore subject to some bias. Officials therefore rely on their trusted networks of peers for lessons as here they can access the ‘real implementation’ story and the unwritten lessons. Organisations which have a culture that is supportive of learning from elsewhere had strong and broad networks of external contacts and resourced their development whilst others are more insular or inward looking and reluctant to invest in policy lessons from elsewhere. Solutions to the problems identified in the evidence base are proposed
"Spice", "Kryptonite", "Black Mamba": An overview of brand names and marketing stragtegies of Novel Psychoactive Substances on the Web
Novel Psychoactive Substances (NPSs) are often sold online as “legal” and “safer” alternatives to International Controlled Drugs (ICDs) with captivating marketing strategies. Our aim was to review and summarize such strategies in terms of the appearance of the products, the brand names, and the latest trends in the illicit online marketplaces. Methods: Scientific data were searched in PsychInfo and Pubmed databases; results were integrated with an extensive monitoring of Internet (websites, online shops, chat rooms, fora, social networks) and media sources in nine languages (English, French, Farsi, Portuguese, Arabic, Russian, Spanish, and Chinese simplified/traditional) available from secure databases of the Global Public Health Intelligence Network. Results: Evolving strategies for the online diffusion and the retail of NPSs have been identified, including discounts and periodic offers on chosen products. Advertisements and new brand names have been designed to attract customers, especially young people. An increased number of retailers have been recorded as well as new Web platforms and privacy systems. Discussion: NPSs represent an unprecedented challenge in the field of public health with social, cultural, legal, and political implications.Web monitoring activities are essential for mapping the diffusion of NPSs and for supporting innovative Web-based prevention programmes.Peer reviewedSubmitted Versio
A Late Cretaceous true polar wander oscillation
True polar wander (TPW), or planetary reorientation, is well documented for other planets and moons and for Earth at present day with satellites, but testing its prevalence in Earth’s past is complicated by simultaneous motions due to plate tectonics. Debate has surrounded the existence of Late Cretaceous TPW ca. 84 million years ago (Ma). Classic palaeomagnetic data from the Scaglia Rossa limestone of Italy are the primary argument against the existence of ca. 84 Ma TPW. Here we present a new high-resolution palaeomagnetic record from two overlapping stratigraphic sections in Italy that provides evidence for a ~12° TPW oscillation from 86 to 78 Ma. This observation represents the most recent large-scale TPW documented and challenges the notion that the spin axis has been largely stable over the past 100 million years
The effect of laser shock peening on hardness and microstructure in a welded marine steel
Residual stress is generally considered as the main criterion in laser shock peening for enhancement of fatigue life. However, changes in material hardness, microstructure and surface roughness can also affect component performance. These three aspects are investigated in this paper for welded marine steel samples subjected to laser peening. After laser peening an increase in hardness was seen across the weld and parent metal, with the local hardness dependent upon the initial hardness of the region before peening. The increase was relatively higher for the weld metal which had lower initial hardness. The local surface displacement profiles reflected the number of laser peening layers applied, and the peening also affected the distortion of the specimen after welding
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