2,538 research outputs found

    Pull-out and push-in tests of bonded steel strands

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    Martí Vargas, JR. (2013). Pull-out and push-in tests of bonded steel strands. Magazine of Concrete Research. 65(18):1128-1131. doi:10.1680/macr.13.00061S112811316518Balázs LG .Bond Model with Non-Linear Bond-Slip Law, 1987, Politecnico di Milano, Italy, 395–430, Studi e Ricerche, Post-Graduate Course for Reinforced Concrete Structures, V.8/86.Balazs, G. L. (1992). Transfer Control of Prestressing Strands. PCI Journal, 37(6), 60-71. doi:10.15554/pcij.11011992.60.71Balazs, G. L. (1993). Transfer Length of Prestressing Strand as a Function of Draw-In and Initial Prestress. PCI Journal, 38(2), 86-93. doi:10.15554/pcij.03011993.86.93Balázs, G. L. (2007). Connecting Reinforcement to Concrete by Bond. Beton- und Stahlbetonbau, 102(S1), 46-50. doi:10.1002/best.200710109Carmo RNF .Ancoragem de Armaduras Pré-Esforçadas por Pré-Tensão. MSc thesis, 1999, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, Portugal, (in Portuguese).Faria, D. M. V., Lúcio, V. J. G., & Pinho Ramos, A. (2011). Pull-out and push-in tests of bonded steel strands. Magazine of Concrete Research, 63(9), 689-705. doi:10.1680/macr.2011.63.9.689Faria, D. M. V., Lúcio, V. J. G., & Ramos, A. P. (2011). Strengthening of flat slabs with post-tensioning using anchorages by bonding. Engineering Structures, 33(6), 2025-2043. doi:10.1016/j.engstruct.2011.02.039Faria, D. M. V., Lúcio, V. J. G., & Pinho Ramos, A. (2012). Post-punching behaviour of flat slabs strengthened with a new technique using post-tensioning. Engineering Structures, 40, 383-397. doi:10.1016/j.engstruct.2012.03.014Laldji S .Bond Characteristics of Prestressing Strand in Grout. MPhil thesis, 1987, University of Leicester, UK.Laldji, S., & Young, A. G. (1988). Bond between steel strand and cement grout in ground anchorages. Magazine of Concrete Research, 40(143), 90-98. doi:10.1680/macr.1988.40.143.90Lopes, S. M. R., & do Carmo, R. N. F. (2002). Bond of prestressed strands to concrete: transfer rate and relationship between transmission length and tendon draw-in. Structural Concrete, 3(3), 117-126. doi:10.1680/stco.2002.3.3.117Martí-Vargas, J. R., Serna-Ros, P., Fernández-Prada, M. A., Miguel-Sosa, P. F., & Arbeláez, C. A. (2006). Test method for determination of the transmission and anchorage lengths in prestressed reinforcement. Magazine of Concrete Research, 58(1), 21-29. doi:10.1680/macr.2006.58.1.21Marti-Vargas, J. R., Arbelaez, C. A., Serna-Ros, P., Navarro-Gregori, J., & Pallares-Rubio, L. (2007). Analytical model for transfer length prediction of 13 mm prestressing strand. Structural Engineering and Mechanics, 26(2), 211-229. doi:10.12989/sem.2007.26.2.211Palmer, K. D., & Schultz, A. E. (2011). Experimental investigation of the web-shear strength of deep hollow-core units. PCI Journal, 56(4), 83-104. doi:10.15554/pcij.09012011.83.10

    The effects of rational and irrational coach team talks on the cognitive appraisal and achievement goal orientation of varsity football athletes

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    The effects of rational and irrational coach team talks on cognitive appraisal and achievement goal orientation were examined. During the half-time interval of a 60-minute football match, 25 male varsity football athletes (Mage = 20.20; SD ± 1.38 years) received a rational (n = 13) or an irrational (n = 12) team talk from a coach. Irrational and rational beliefs were measured before the football match. Task engagement, cognitive appraisal (challenge and threat), and achievement goal orientation (approach and avoidance) regarding second-half football performance were measured following team-talk delivery. Athletes in the rational team talk condition reported significantly lower threat appraisal and avoidance goal orientation than athletes in the irrational team talk condition. No significant between-condition differences emerged for challenge appraisal and approach goal orientation. For coaching practice, data suggest that communicating rational or irrational beliefs to football athletes through a half time team talk will influence appraisal and achievement goal orientation regarding upcoming performance. Keywords Rational emotive behaviour therapy, irrational beliefs, rational beliefs, appraisal, achievement goal

    Recent Developments in Low-Level Lead Exposure and Intellectual Impairment in Children

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    In the last decade children’s blood lead levels have fallen significantly in a number of countries, and current mean levels in developed countries are in the region of 3 μg/dL. Despite this reduction, childhood lead poisoning continues to be a major public health problem for certain at-risk groups of children, and concerns remain over the effects of lead on intellectual development in infants and children. The evidence for lowered cognitive ability in children exposed to lead has come largely from prospective epidemiologic studies. The current World Health Organization/Centers for Disease Control and Prevention blood level of concern reflects this and stands at 10 μg/dL. However, a recent study on a cohort of children whose lifetime peak blood levels were consistently < 10 μg/dL has extended the association of blood lead and intellectual impairment to lower levels of lead exposure and suggests there is no safety margin at existing exposures. Because of the importance of this finding, we reviewed this study in detail along with other recent developments in the field of low-level lead exposure and children’s cognitive development. We conclude that these findings are important scientifically, and efforts should continue to reduce childhood exposure. However, from a public health perspective, exposure to lead should be seen within the many other risk factors impacting on normal childhood development, in particular the influence of the learning environment itself. Current lead exposure accounts for a very small amount of variance in cognitive ability (1–4%), whereas social and parenting factors account for 40% or more

    Orally active antischistosomal early leads identified from the open access malaria box.

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    BACKGROUND: Worldwide hundreds of millions of schistosomiasis patients rely on treatment with a single drug, praziquantel. Therapeutic limitations and the threat of praziquantel resistance underline the need to discover and develop next generation drugs. METHODOLOGY: We studied the antischistosomal properties of the Medicines for Malaria Venture (MMV) malaria box containing 200 diverse drug-like and 200 probe-like compounds with confirmed in vitro activity against Plasmodium falciparum. Compounds were tested against schistosomula and adult Schistosoma mansoni in vitro. Based on in vitro performance, available pharmacokinetic profiles and toxicity data, selected compounds were investigated in vivo. PRINCIPAL FINDINGS: Promising antischistosomal activity (IC50: 1.4-9.5 µM) was observed for 34 compounds against schistosomula. Three compounds presented IC50 values between 0.8 and 1.3 µM against adult S. mansoni. Two promising early leads were identified, namely a N,N'-diarylurea and a 2,3-dianilinoquinoxaline. Treatment of S. mansoni infected mice with a single oral 400 mg/kg dose of these drugs resulted in significant worm burden reductions of 52.5% and 40.8%, respectively. CONCLUSIONS/SIGNIFICANCE: The two candidates identified by investigating the MMV malaria box are characterized by good pharmacokinetic profiles, low cytotoxic potential and easy chemistry and therefore offer an excellent starting point for antischistosomal drug discovery and development

    Inertial sensor real-time feedback enhances the learning of cervical spine manipulation: a prospective study.

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    BACKGROUND: Cervical Spinal Manipulation (CSM) is considered a high-level skill of the central nervous system because it requires bimanual coordinated rhythmical movements therefore necessitating training to achieve proficiency. The objective of the present study was to investigate the effect of real-time feedback on the performance of CSM. METHODS: Six postgraduate physiotherapy students attending a training workshop on Cervical Spine Manipulation Technique (CSMT) using inertial sensor derived real-time feedback participated in this study. The key variables were pre-manipulative position, angular displacement of the thrust and angular velocity of the thrust. Differences between variables before and after training were investigated using t-tests. RESULTS: There were no significant differences after training for the pre-manipulative position (rotation p = 0.549; side bending p = 0.312) or for thrust displacement (rotation p = 0.247; side bending p = 0.314). Thrust angular velocity demonstrated a significant difference following training for rotation (pre-training mean (sd) 48.9°/s (35.1); post-training mean (sd) 96.9°/s (53.9); p = 0.027) but not for side bending (p = 0.521). CONCLUSION: Real-time feedback using an inertial sensor may be valuable in the development of specific manipulative skill. Future studies investigating manipulation could consider a randomized controlled trial using inertial sensor real time feedback compared to traditional training

    Effect of chitosan essential oil films on the storage-keeping quality of pork meat products

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    Edible films based on chitosan were prepared, with and without basil or thyme essential oils, with the aim of assessing their protective ability against lipid oxidation and their antimicrobial activity. Chitosan films had good oxygenbarrier properties, which were worsened by essential oil addition, especially when the film equilibrium moisture content increased. Due to the oxygen-barrier effect, all the films effectively protected pork fat from oxidation, in comparison to unprotected samples. In spite of the worsening of the oxygen-barrier properties, the films with essential oils were more effective than those of pure chitosan, which points to the chemical action of specific antioxidant compounds of the oils. Films were effective to control microbial growth in minced pork meat, although the incorporation of essential oils did not improve their antimicrobial activity. Throughout the storage, the films led to colour changes in minced pork meat associated with the conversion of myoglobin into metmyoglobin due to the reduction of the oxygen availability.The authors acknowledge the financial support provided by the Universitat Politecnica de Valencia (PAID-06-09-2834), Generalitat Valenciana (GV/2010/082) and Ministerio de Educacion y Ciencia (AGL2010-20694). Author J. Bonilla is deeply grateful to Generalitat Valenciana for a Santiago Grisolia Grant.Bonilla Lagos, MJ.; Vargas, M.; Atarés Huerta, LM.; Chiralt Boix, MA. (2014). Effect of chitosan essential oil films on the storage-keeping quality of pork meat products. Food and Bioprocess Technology. 7(8):2443-2450. https://doi.org/10.1007/s11947-014-1329-3S2443245078ASTM D3985. (1995). Standard test method for oxygen gas transmission rate through plastic films and sheeting using a coulometric sensor. 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New preservation technologies: possibilities and limitations. International Dairy Journal, 14, 273–285.Di Pasqua, R., Hoskins, N., Betts, G., & Mauriello, G. (2006). Changes in membrane fatty acids composition of microbial cells induced by addiction of thymol, carvacrol, limonene, cinnamaldehyde and eugenol in the growing media. Journal of Agricultural and Food Chemistry, 54, 2745–2749.Di Pierro, P., Sorrentino, A., Mariniello, L., Giosafatto, C. V. L., & Porta, R. (2011). Chitosan/whey protein film as active coating to extend Ricotta cheese shelf-life. LWT--Food Science and Technology, 44, 2324–2327.Fabra, M. J., Talens, P., Gavara, R., & Chiralt, A. (2012). Barrier properties of sodium caseinate films as affected by lipid composition and moisture content. Journal of Food Engineering, 109(3), 372–379.Gaysinsky, S., Davidson, P. M., Bruce, B. D., & Weiss, J. (2005). Growth inhibition of E. 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    New miniPromoter Ple345 (NEFL) drives strong and specific expression in retinal ganglion cells of mouse and primate retina.

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    Retinal gene therapy is leading the neurological gene therapy field, with 32 ongoing clinical trials of recombinant adeno-associated virus (rAAV)-based therapies. Importantly, over 50% of those trials are using restricted promoters from human genes. Promoters that restrict expression have demonstrated increased efficacy and can limit the therapeutic to the target cells thereby reducing unwanted off-target effects. Retinal ganglion cells are a critical target in ocular gene therapy; they are involved in common diseases such as glaucoma, rare diseases such as Leber's hereditary optic neuropathy, and in revolutionary optogenetic treatments. Here, we used computational biology and mined the human genome for the best genes from which to develop a novel minimal promoter element(s) designed for expression in restricted cell types (MiniPromoter) to improve the safety and efficacy of retinal ganglion cell gene therapy. Gene selection included the use of the first available droplet-based single-cell RNA sequencing (Drop-seq) dataset, and promoter design was bioinformatically driven and informed by a wide range of genomics datasets. We tested seven promoter designs from four genes in rAAV for specificity and quantified expression strength in retinal ganglion cells in mouse, and then the single best in nonhuman primate retina. Thus, we developed a new human-DNA MiniPromoter, Ple345 (NEFL), which in combination with intravitreal delivery in rAAV9 showed specific and robust expression in the retinal ganglion cells of the nonhuman-primate rhesus macaque retina. In mouse, we also developed MiniPromoters expressing in retinal ganglion cells, the hippocampus of the brain, a pan neuronal pattern in the brain, and peripheral nerves. As single-cell transcriptomics such as Drop-seq become available for other cell types, many new opportunities for additional novel restricted MiniPromoters will present

    Iron carbonate formation kinetics onto corroding and pre-filmed carbon steel surfaces in carbon dioxide corrosion environments

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    This work investigates the Corrosion Layer Accumulation Rate (CLAR) of iron carbonate (FeCO3) onto X65 carbon steel in carbon dioxide containing environments using the direct method of corrosion layer mass gain measurement. Glass cell experiments were performed at 80 °C and pH 6.3 or 6.8 over a range of bulk FeCO3 saturation ratios using both actively corroding carbon steel and steel pre-filmed with FeCO3. The CLARs obtained from experiments using actively corroding samples displayed strong agreement with the most recently developed precipitation model by Sun and Nesic at high supersaturation for pH 6.3 and 6.8, but a disparity at low supersaturation for the solution at pH 6.8. The observed discrepancy was attributed to the significant difference in surface saturation ratio between the two conditions when the steel is actively corroding. CLARs determined for pre-FeCO3 filmed carbon steel show that the kinetics of FeCO3 formation reduce significantly once the film establishes a protective barrier at lower values of bulk supersaturation. The results highlight the contrast between surface layer accumulation kinetics in the early stages of growth and those encountered in the long-term after the development of a protective film
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