2,426 research outputs found
Histamine production during the anti-allograft response. Demonstration of a new lymphokine enhancing histamine synthesis
Histamine production is greatly increased during culture of allograft recipient spleen cells in the presence of immunizing cells (secondary mixed leukocyte cultures [MLC]) as compared to that found in primary MLC (i.e., without previous allograft). This phenomenon appears after 24 h of culture and reaches its maximum at 48 h. Optimal increased histamine production is observed when MLC is performed with spleen cells removed from mice during rejection. This increased production of histamine during secondary MLC results from the action of a lymphokine: the histamine-producing cell stimulating factor (HCSF). This factor is released by T lymphocytes. Its production requires specific stimulation of the recipient lymphocytes because increase in histamine production during secondary MLC can be only observed when recipient cells are cultured with stimulating cells bearing at least one homology at K or D loci with immunizing cells. HCSF acts on a cell which is present in bone marrow, spleen, blood, and peritoneal cells but absent in thymus or lymph node cells. This target cell is found in the less-dense layer of a discontinuous Ficoll-gradient of bone marrow cells. HCSF is heat stable, destroyed by trypsin treatment, and has a molecular weight between 50,000 and 100,000. It acts on its target cells by increasing histidine decarboxylase activity
New Russulaceae species in south-east Queensland
Russula species are ectomycorrhizal basidiomycetes common throughout Australian woodlands. Molecular and morphological examination of Russula specimens from various sites in South-east Queensland has uncovered a number of phylogenetically diverse and potentially undescribed specimens. At this stage, most of these remain as individual specimens. However, several specimens have been grouped into project species. In this presentation, two potentially new species of Russula will be described. Both species are widespread on red to black clay soils in the Toowoomba region and appear to be phylogenetically related to each other. Project species 1 has a white stipe which developed a pink flush after collection and red to pink centrally depressed cap with white gills. The spores of this species were subglobose, white and ornamented with amyloid warts connected in short chains. The second species, project species 3, is macroscopically similar, differing with its larger size, purple-pink cap colour, and rougher cap texture. Its spores are globose to subglobose, white and ornamented with small amyloid warts connected in short chains. Continued molecular and morphological studies of the Russula species of South-east Queensland may uncover more novel Australian species
Observational Learning During Simulation-Based Training in Arthroscopy: Is It Useful to Novices?
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.OBJECTIVE: Observing experts constitutes an important and common learning experience for surgical residents before operating under direct guidance. However, studies suggest that exclusively observing experts may induce suboptimal motor learning, and watching errors from non-experts performing simple motor tasks may generate better performance. We investigated whether observational learning is transferrable to arthroscopy learning using virtual reality (VR) simulation. SETTING/DESIGN: In our surgical simulation laboratory, we compared students learning basic skills on a VR arthroscopy simulator after watching an expert video demonstration of VR arthroscopy tasks or a non-expert video demonstration of the same tasks to a Control group without video demonstration. Ninety students in 3 observing groups (expert, non-expert, and Control) subsequently completed the same procedure on a VR arthroscopy simulator. We hypothesized the non-expert-watching group would outperform the expert-watching group, and both groups to outperform the Control group. We examined performance pretest, posttest, and 1 week later. PARTICIPANTS: Participants were recruited from the final year of medical school and the very early first year of surgical residency training programs (orthopaedic surgery, urology, plastic surgery, and general surgery) at Western University (Ontario, Canada). RESULTS: All participants improved their overall performance from pretest to retention (p < 0.001). At initial retention testing, non-expert-watching group outperformed the other groups in camera path length p < 0.05 and time to completion, p < 0.05, and both the expert/non-expert groups surpassed the Control group in camera path length (p < 0.05). CONCLUSION: We suggest that error-observation may contribute to skills improvement in the non-expert-watching group. Allowing novices to observe techniques/errors of other novices may assist internalization of specific movements/skills required for effective motor performances. This study highlights the potential effect of observational learning on surgical skills acquisition and offers preliminary evidence for peer-based practice (combined non-experts and experts) as a complementary surgical motor skills training strategy.This project was supported by a PhysiciansŚł Services Incorporated (PSI) Foundation, Canada grant. Funds were used to pay for salary and employee benefits (LvE). The PSI Foundation did not play a role in the investigation
Effects of fluoride on primary cultured haemocytes from the marine gastropod Haliotis tuberculata
International audienceAs a consequence of human's activities, fluoride concentration in many aquatic ecosystems is significantly increasing. Nevertheless, little is known about fluoride toxicity to aquatic life. In this study the effect of exposure to different concentrations of sodium fluoride (2, 10, 50, 250 and 1,250 ÎŒg mL â1) during 24 h on primary cultured haemocytes of the gastropod Haliotis tuberculata was realized. Results indicate no significant effect of NaF on cell viability, Lysosomal membrane stability, phagocytosis and ROS production at concentrations of 2, 10, 50 and 250 ÎŒg mL â1. Nevertheless, lysosomal membrane alterations, a decrease of phagocytosis and morphological changes of H. tuberculata haemocytes were observed at concentration of 1,250 ”g mL â1 NaF suggesting a potential impact of NaF at high concentration in the environment
Optimization of the Touchscreen-Based Visuomotor Conditional Learning Task in Mice
The translational gap between animal models and clinical trials is a longstanding, yet largely unresolved, limitation in the study of cognition. This discrepancy is largely due to the differences in how cognition is assessed in animal models compared to those in clinical populations. In the stimulus-response (S-R) learning literature, for example, the techniques used to assess the acquisition of habitual behaviour differ greatly across species, leading to poor cross-species translation and often conflicting results. As a result, we set out to optimize a S-R learning task in mice using the touchscreen-based operant technologies. Similar to human studies, this touchscreen technique encourages animals to respond to visual stimuli displayed on a touchscreen according to a specific rule. Allowing for very similar, if not identical, cognitive assays in mice and men, this technique promotes high translational potential and a high degree of standardisation. Originally developed for rats, the Visuomotor Conditional Learning (VMCL) task encourages animals to learn arbitrary associations between visual stimuli and motor responses. In naĂŻve C57BL/6 mice, we sought to optimize VMCL task parameters to promote better and more efficient responding, identifying the length of inter-trial intervals and the limited hold period as two potential candidates. The validation of this task will provide a novel means through which to study the neural correlates of S-R learning, and its use in conjunction with fiber photometry recordings may be provided
Setting an International Research Agenda for Fear of Cancer Recurrence: an online delphi consensus study
This Document is Protected by copyright and was first published by Frontiers. All rights reserved. it is reproduced with permissionBackground: Fear of cancer recurrence (FCR) is common amongst cancer survivors. There is rapidly growing research interest in FCR but a need to prioritise research to address the most pressing clinical issues and reduce duplication and fragmentation of effort. This study aimed to establish international consensus among clinical and academic FCR experts regarding priorities for FCR research.
Methods: Members of the International Psycho-oncology Society (IPOS) Fear of Cancer Recurrence Special Interest Group (FORwards) were invited to participate in an online Delphi study. Research domains identified in Round 1 were presented and discussed at a focus group (Round 2) to consolidate the domains and items prior to presentation in further survey rounds (Round 3) aimed at gaining consensus on research priorities of international significance.
Results: Thirty four research items were identified in Round 1 and 33 of the items were consolidated into 6 overarching themes through a focus group discussion with FCR experts. The 33 research items were presented in subsequent rounds of the delphi technique. Twenty one participants contributed to delphi round 1, 16 in round 2 and 25 and 29 participants for subsequent delphi rounds. Consensus was reached for 27 items in round 3.1. A further 4 research items were identified by panellists and included in round 3.2. After round 3.2, 35 individual research items were ratified by the panellists. Given the high levels of consensus and stability between rounds no further rounds were conducted. Overall intervention research was considered the most important focus for FCR research. Panellists identified models of care that facilitate greater access to FCR treatment and evaluation of the effectiveness of FCR interventions in real world settings as the two research items of highest priority. Defining the mechanisms of action and active components across FCR/P interventions, was the third highest priority identified.
Conclusions: The findings of this study outline a research agenda for international FCR research. Intervention research to identify models of care that increase access to treatment, are based on a flexible approach based on symptom severity and can be delivered within routine clinical care, were identified as research areas to prioritise. Greater understanding of the active components and mechanisms of action of existing FCR interventions will facilitate increased tailoring of interventions to meet patient need
Molecular identification of fungal endophytes in Dipodium roseum roots
Dipodium or hyacinth orchids are large, fleshy, terrestrial orchids commonly seen in summer in Australian woodlands. Most species have limited chlorophyll, appear to be non-photosynthetic and rely on mycorrhizal fungi for their nutrition. Previous molecular investigations of the endophytic fungi of roots of Dipodium variegatum and Dipodium hamiltonianum have shown that the orchids are largely colonised by members of the ectomycorrhizal basidiomycete family, the Russulaceae. The fact that these plants consistently grew close to the base of Eucalyptus and Callitris trees suggested that the orchids acquire carbon and minerals from the tree host via an ectomycorrhizal connection. In the current project the fungal endophytes of Dipodium roseum were investigated for the first time. Orchid roots were sampled from multiple sites over two seasons in southern Queensland, Australia. DNA was extracted from colonised roots and isolated pelotons of the orchid. PCR amplification was conducted using ITS1F and ITS4 primers and following DNA purification, sent for Sanger sequencing at the Australian Genome Research Facility. BLAST searches of returned sequences against the GenBank database revealed a variety of fungi colonising the roots of D. roseum. This included a number of fungi not previously found as root endophytes of Orchidaceae species
A two-phase flow model to simulate mold filling and saturation in Resin Transfer Molding
The final publication is available at Springer via http://dx.doi.org/10.1007/s12289-015-1225-zThis paper addresses the numerical simulation of void formation and transport during mold filling in Resin Transfer Molding (RTM). The saturation equation, based on a two-phase flow model resin/air, is coupled with Darcy s law and mass conservation to simulate the unsaturated filling flow
that takes place in a RTM mold when resin is injected through the fiber bed. These equations lead to a system composed of an advection diffusion equation for saturation including capillary effects and an elliptic equation for pressure taking into account the effect of air residual saturation. The model introduces the relative permeability as a function of resin saturation. When capillary effects are omitted, the hyperbolic nature of the saturation equation and its strong coupling with Darcy
equation through relative permeability represent a challenging numerical issue. The combination of the constitutive physical laws relating permeability to saturation with the coupled system
of the pressure and saturation equations allows predicting the saturation profiles. The model was validated by comparison with experimental data obtained for a fiberglass reinforcement
injected in a RTM mold at constant flow rate. The saturation measured as a function of time during the resin impregnation of the fiber bed compared very well with numerical predictions.The authors acknowledge financial support of the Spanish Government (Projects DPI2010-20333 and DPI2013-44903-R-AR), of the National Science and Research Council of Canada (NSERC) and of the Canada Reseach Chair (CRC) program.GascĂłn MartĂnez, ML.; GarcĂa Manrique, JA.; Lebel, F.; Ruiz, E.; Trochu, F. (2016). A two-phase flow model to simulate mold filling and saturation in Resin Transfer Molding. International Journal of Material Forming. 9(2):229-239. doi:10.1007/s12289-015-1225-zS22923992Patel N, Lee LJ (1996) Modeling of void formation and removal in liquid composite molding. Part I: wettability analysis. Polym Compos 17(1):96â103Ruiz E, Achim V, Soukane S, Trochu F, BrĂ©ard J (2006) Optimization of injection flow rate to minimize micro/macro-voids formation in resin transfer molded composites. Compos Sci Technol 66(3â4):475â486Trochu F, Ruiz E, Achim V, Soukane S (2006) Advanced numerical simulation of liquid composite molding for process analysis and optimization. Compos A: Appl Sci Manuf 37(6):890â902Park CH, Lee W (2011) Modeling void formation and unsaturated flow in liquid composite molding processes: a survey and review. J Reinf Plast Compos 30(11):957â977Pillai KM (2004) Modeling the unsaturated flow in liquid composite molding processes: a review and some thoughts. J Compos Mater 38(23):2097â2118Breard J, Saouab A, Bouquet G (2003) Numerical simulation of void formation in LCM. Compos A: Appl Sci Manuf 34:517â523Breard J, Henzel Y, Trochu F, Gauvin R (2003) Analysis of dynamic flows through porous media. Part I: comparison between saturated and unsaturated flows in fibrous reinforcements. Polym Compos 24(3):391â408Parnas RS, Phelan FR Jr (1991) The effect of heterogeneous porous media on mold filling in Resin Transfer Molding. SAMPE Q 22(2):53â60Parseval DY, Pillai KM, Advani SG (1997) A simple model for the variation of permeability due to partial saturation in dual scale porous media. Transp Porous Media 27(3):243â264Pillai KM (2002) Governing equations for unsaturated flow through woven fiber mats. Part 1. Isothermal flows. Compos A: Appl Sci Manuf 33(7):1007â1019Simacek P, Advani SG (2003) A numerical model to predict fiber tow saturation during Liquid Composite Molding. Compos Sci Technol 63:1725â1736GarcĂa JA, GascĂłn L, Chinesta F (2010) A flux limiter strategy for solving the saturation equation in RTM process simulation. Compos A: Appl Sci Manuf 41:78â82Chui WK, Glimm J, Tangerman FM, Jardine AP, Madsen JS, Donnellan TM, Leek R (1997) Process modeling in Resin Transfer Molding as a method to enhance product quality. SIAM Rev 39(4):714â727Nordlund M, Michaud V (2012) Dynamic saturation curve measurement for resin flow in glass fibre reinforcement. Compos A: Appl Sci Manuf 43:333â343GarcĂa JA, Ll G, Chinesta F (2003) A fixed mesh numerical method for modelling the flow in liquid composites moulding processes using a volume of fluid technique. Comput Methods Appl Mech Eng 192(7â8):877â893GarcĂa JA, Ll G, Chinesta F, Trochu F, Ruiz E (2010) An efficient solver of the saturation equation in liquid composite molding processes. Int J Mater Form 3(2):1295â1302Lebel F (2012) ContrĂŽle de la fabrication des composites par injection sur renforts. Ăcole Polytechnique de MontrĂ©al, CanadaVan Genuchten MT (1980) Closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci Soc Am J 44(5):892â898Buckley SE, Leverett MC (1942) Mechanism of fluid displacement in sands. Pet Trans AWME 146:107â116Lundstrom TS, Gebart BR (1994) Influence from process parameters on void formation in Resin Transfer Molding. Polym Compos 15(1):25â33Lundstrom TS (1997) Measurement of void collapse during Resin Transfer Molding. Compos A: Appl Sci Manuf 28(3):201â214Lundstrom TS, Frishfelds V, Jakovics A (2010) Bubble formation and motion in non-crimp fabrics with perturbed bundle geometry. Compos A: Appl Sci Manuf 41:83â92Lebel F, Fanaei A, Ruiz E, Trochu F (2012) Experimental characterization by fluorescence of capillary flows in the fiber tows of engineering fabrics. Open J Inorg Non-Metallic Mater 2(3):25â45Brooks RH, Corey AT (1964) Hydraulic properties of porous media. Colorado State University. Hydrology Papers 1â37Corey AT (1954) The interrelation between gas and oil relative permeabilities. Prod Monthly 19(1):38â4
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