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Sample records for strength influences outcomes

  1. Promoting positive outcomes through strengths interventions : A literature review

    NARCIS (Netherlands)

    Ghielen, S.T.S.; van Woerkom, M.; Meyers, M.C.

    2018-01-01

    This paper reviews studies of strengths interventions published between 2011 and 2016. Strengths interventions aim to promote well-being or other positive outcomes by facilitating strengths identification, and sometimes also strengths use and/or development. The present review provides an overview

  2. G×E Interaction Influences Trajectories of Hand Grip Strength

    DEFF Research Database (Denmark)

    Petersen, Inge; Pedersen, Nancy L; Rantanen, Taina

    2016-01-01

    Age-related decline in grip strength predicts later life disability, frailty, lower well-being and cognitive change. While grip strength is heritable, genetic influence on change in grip strength has been relatively ignored, with non-shared environmental influence identified as the primary contri...

  3. Does cruciate retention primary total knee arthroplasty affect proprioception, strength and clinical outcome?

    Science.gov (United States)

    Vandekerckhove, Pieter-Jan T K; Parys, Roel; Tampere, Thomas; Linden, Patrick; Van den Daelen, Luc; Verdonk, Peter C

    2015-06-01

    It remains unclear what the contribution of the PCL is in total knee arthroplasty (TKA). The goal of this study was to investigate the influence of the PCL in TKA in relationship to clinical outcome, strength and proprioception. Two arthroplasty designs were compared: a posterior cruciate-substituting (PS) and a posterior cruciate-retaining (CR) TKA. A retrospective analysis was performed of 27 CR and 18 PS implants with a minimum of 1 year in vivo. Both groups were compared in terms of clinical outcome (range of motion, visual analogue scale for pain, Hospital for Special Surgery Knee Scoring system, Lysholm score and Knee Injury and Osteoarthritis Outcome Score), strength (Biodex System 3 Dynamometer(®)) and proprioception (balance and postural control using the Balance Master system(®)). Each design was also compared to the non-operated contralateral side in terms of strength and proprioception. There were no significant differences between both designs in terms of clinical outcome and strength. In terms of proprioception, only the rhythmic weight test at slow and moderate speed shifting from left to right was significant in favour of the CR design. None of the unilateral stance tests showed any significant difference between both designs. There was no difference in terms of strength and proprioception between the operated side and the non-operated side. Retaining the PCL in TKA does not result in an improved performance in terms of clinical outcome and proprioception and does not show any difference in muscle strength. III.

  4. Geometry and gravity influences on strength capability

    Science.gov (United States)

    Poliner, Jeffrey; Wilmington, Robert P.; Klute, Glenn K.

    1994-01-01

    Strength, defined as the capability of an individual to produce an external force, is one of the most important determining characteristics of human performance. Knowledge of strength capabilities of a group of individuals can be applied to designing equipment and workplaces, planning procedures and tasks, and training individuals. In the manned space program, with the high risk and cost associated with spaceflight, information pertaining to human performance is important to ensuring mission success and safety. Knowledge of individual's strength capabilities in weightlessness is of interest within many areas of NASA, including workplace design, tool development, and mission planning. The weightless environment of space places the human body in a completely different context. Astronauts perform a variety of manual tasks while in orbit. Their ability to perform these tasks is partly determined by their strength capability as demanded by that particular task. Thus, an important step in task planning, development, and evaluation is to determine the ability of the humans performing it. This can be accomplished by utilizing quantitative techniques to develop a database of human strength capabilities in weightlessness. Furthermore, if strength characteristics are known, equipment and tools can be built to optimize the operators' performance. This study examined strength in performing a simple task, specifically, using a tool to apply a torque to a fixture.

  5. Influence of processing factors over concrete strength.

    Science.gov (United States)

    Kara, K. A.; Dolzhenko, A. V.; Zharikov, I. S.

    2018-03-01

    Construction of facilities of cast in-situ reinforced concrete poses additional requirements to quality of material, peculiarities of the construction process may sometimes lead to appearance of lamination planes and inhomogeneity of concrete, which reduce strength of the material and structure as a whole. Technology compliance while working with cast in-situ concrete has a significant impact onto the concrete strength. Such process factors as concrete curing, vibration and compaction of the concrete mixture, temperature treatment, etc., when they are countered or inadequately followed lead to a significant reduction in concrete strength. Here, the authors experimentally quantitatively determine the loss of strength in in-situ cast concrete structures due to inadequate following of process requirements, in comparison with full compliance.

  6. INFLUENCE OF STRENGTH TRAINING PROGRAM ON ISOMETRIC MUSCLE STRENGTH IN YOUNG ATHLETES

    Directory of Open Access Journals (Sweden)

    Dragan Radovanovic

    2007-10-01

    Full Text Available Strength training, or resistance training, is a form of physical conditioning used to increase the ability to resist force. Since muscular strength is required for success in many sports, it is logical to assume that stronger and more powerful young athletes will achieve better results. The aim of the study was to examine the effects of strength training on young athletes. An eight-week strength training program for developing muscle strength was performed in this study. Training protocol was designed specifically for young adolescent’s athletes. The program consisted of exercises for lower and upper body, abdominal and lower back muscles. The programs did not involve the maximal (1-3 repetitions maximum and other very hard intensity exercises that may had negative effect on young athletes. The results showed that strength training program had positive effects on maximal isometric muscle force (Fmax and motor skill. The increase presents the combined influence of strength training and growth.

  7. Influence of multiaxial preloading on the strength of concrete

    International Nuclear Information System (INIS)

    Linse, D.

    1975-01-01

    In a preliminary study about the influence of the loading direction discs of 20/20/5 cm were loaded at different stress-rates in one direction, then unloaded and loaded up to failure again. Two series of each about 15 specimens were tested: the first series was reloaded in the same direction as it was loaded before. If the preloading was not greater than about 90% of the original short-term uniaxial strength βsub(p), one could achieve in the second loading a higher strength than the strength βsub(p). The second series was reloaded normal to the direction of preloading. By an other series of about 50 specimens the influence of triaxial preloading on the uniaxial strength of concrete was tested. Cubes of 10cm were loaded by brush bearing platens up to a stress which was maximally three times higher than the uniaxial short-term strength βsub(p), then unloaded and tested again under uniaxial compression. The achieved ultimate strength of the cubes at the second loading was obviously dependent upon the stress-state and the stress-rate of the preloading. Multiaxial preloading which is far below the ultimate multiaxial strength can considerably defect the remaining strength of concrete. The decrease in strength was defined by the reduction of the uniaxial strength. It can be assumed that the remaining multiaxial strength is reduced at least to the same rate. Further tests are planned

  8. Influence of silica fume on the strength of high strength concrete

    International Nuclear Information System (INIS)

    Akram, T.; Memon, S.A.; Khan, S.A.

    2007-01-01

    HSC (High Strength Concrete) does not become evident by a sudden change in the behavior of 'ordinary strength' concrete. There is a gradual effect that becomes more noticeable when the strength level exceeds about 40-45 MPa. There cannot be a precise level of strength which defines this change in effect. The effects are on strength and workability, requiring us to take into account in our mix proportioning, the ramifications of fineness of cement on workability and of type of aggregate and aggregate/cement ratio on strength. In fact, the selection of materials becomes more critical as the concrete strength increases and that if very high strength is required (100 MPa and higher), relatively few materials may be suitable. An experimental investigation is carried out to evaluate the feasibility of producing HSC using locally available materials and to study the influence of silica fume on the strength of HSC. The main variables in this research is amount of silica fume. The parameters that are kept constant are the amount of cement equal to 580 kg/m3, dosage of HRWRA (High Range Water Reducing Admictures) equal to 4 % by weight of cementitious materials and the ratio of fine aggregate to coarse aggregate (1:2.3). Test results revealed that it is feasible to produce HSC using locally available materials. The optimum percentage of silica fume was found to be 15 % by weight of cement. (author)

  9. Influence of initial imperfections on ultimate strength of spherical shells

    Directory of Open Access Journals (Sweden)

    Chang-Li Yu

    2017-09-01

    Full Text Available Comprehensive consideration regarding influence mechanisms of initial imperfections on ultimate strength of spherical shells is taken to satisfy requirement of deep-sea structural design. The feasibility of innovative numerical procedure that combines welding simulation and non-linear buckling analysis is verified by a good agreement to experimental and theoretical results. Spherical shells with a series of wall thicknesses to radius ratios are studied. Residual stress and deformations from welding process are investigated separately. Variant influence mechanisms are discovered. Residual stress is demonstrated to be influential to stress field and buckling behavior but not to the ultimate strength. Deformations are proved to have a significant impact on ultimate strength. When central angles are less than critical value, concave magnitudes reduce ultimate strengths linearly. However, deformations with central angles above critical value are of much greater harm. Less imperfection susceptibility is found in spherical shells with larger wall thicknesses to radius ratios.

  10. Physical activity, but not sedentary time, influences bone strength in late adolescence.

    Science.gov (United States)

    Tan, Vina Ps; Macdonald, Heather M; Gabel, Leigh; McKay, Heather A

    2018-03-20

    Physical activity is essential for optimal bone strength accrual, but we know little about interactions between physical activity, sedentary time, and bone outcomes in older adolescents. Physical activity (by accelerometer and self-report) positively predicted bone strength and the distal and midshaft tibia in 15-year-old boys and girls. Lean body mass mediated the relationship between physical activity and bone strength in adolescents. To examine the influence of physical activity (PA) and sedentary time on bone strength, structure, and density in older adolescents. We used peripheral quantitative computed tomography to estimate bone strength at the distal tibia (8% site; bone strength index, BSI) and tibial midshaft (50% site; polar strength strain index, SSI p ) in adolescent boys (n = 86; 15.3 ± 0.4 years) and girls (n = 106; 15.3 ± 0.4 years). Using accelerometers (GT1M, Actigraph), we measured moderate-to-vigorous PA (MVPA Accel ), vigorous PA (VPA Accel ), and sedentary time in addition to self-reported MVPA (MVPA PAQ-A ) and impact PA (ImpactPA PAQ-A ). We examined relations between PA and sedentary time and bone outcomes, adjusting for ethnicity, maturity, tibial length, and total body lean mass. At the distal tibia, MVPA Accel and VPA Accel positively predicted BSI (explained 6-7% of the variance, p accounting for lean mass. Sedentary time did not independently predict bone strength at either site. Greater tibial bone strength in active adolescents is mediated, in part, by lean mass. Despite spending most of their day in sedentary pursuits, adolescents' bone strength was not negatively influenced by sedentary time.

  11. influence of molding water content on shear strength characteristic

    African Journals Online (AJOL)

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    INFLUENCE OF MOLDING WATER CONTENT ON SHEAR STRENGTH OF COMPACTED CEMENT KILN DUST, K. J. Osinub. K. J. Osinub. K. J. Osinubi, et al. Nigerian Journal of Technology,. Vol. 34, No. 2, April 2015 267 pavements or as waste containment materials. Therefore, recent studies have been geared towards.

  12. Influence of strength training intensity on subsequent recovery in elderly

    DEFF Research Database (Denmark)

    da Rosa Orssatto, Lucas Bet; de Moura, Bruno Monteiro; de Souza Bezerra, Ewertton

    2018-01-01

    Understanding the influence of strength training intensity on subsequent recovery in elderly is important to avoid reductions in physical function during the days following training. Twenty-two elderly were randomized in two groups: G70 (65.9 ± 4.8 years, n = 11) and G95 (66.9 ± 5.1, n = 11...... in elderly depending on the type of physical function and intensity of training. Higher intensity resulted in greater impairment. Exercise prescription in elderly should take this into account, e.g., by gradually increasing intensity during the first months of strength training. These results have relevance...... for elderly who have to be fit for work or other activities in the days following strength training....

  13. Shear bond strength of metallic brackets: influence of saliva contamination

    Directory of Open Access Journals (Sweden)

    Luciana Borges Retamoso

    2009-06-01

    Full Text Available OBJECTIVE: To evaluate the influence of saliva contamination on shear bond strength and the bond failure pattern of 3 adhesive systems (Transbond XT, AdheSE and Xeno III on orthodontic metallic brackets bonded to human enamel. MATERIAL AND METHODS: Seventy-two permanent human molars were cut longitudinally in a mesiodistal direction, producing seventy-two specimens randomly divided into six groups. Each system was tested under 2 different enamel conditions: no contamination and contaminated with saliva. In T, A and X groups, the adhesive systems were applied to the enamel surface in accordance with manufacturer's instructions. In TS, AS and XS groups, saliva was applied to enamel surface followed by adhesive system application. The samples were stored in distilled water at 37ºC for 24 h, and then tested for shear bond strength in a universal testing machine (Emic, DL 2000 running at a crosshead speed of 1 mm/min. After bond failure, the enamel surfaces were observed under an optical microscope at 40x magnification. RESULTS: The control and contaminated groups showed no significant difference in shear bond strength for the same adhesive system. However, shear bond strength of T group (17.03±4.91 was significantly higher than that of AS (8.58±1.73 and XS (10.39±4.06 groups (p<0.05. Regarding the bond failure pattern, TS group had significantly higher scores of no adhesive remaining on the tooth in the bonding area than other groups considering the adhesive remnant index (ARI used to evaluate the amount of adhesive left on the enamel. CONCLUSIONS: Saliva contamination showed little influence on the 24-h shear bond strength of orthodontic brackets.

  14. The influence of tongue strength on oral viscosity discrimination acuity.

    Science.gov (United States)

    Steele, Catriona M

    2018-06-01

    The ability to generate tongue pressures is widely considered to be critical for liquid bolus propulsion in swallowing. It has been proposed that the application of tongue pressure may also serve the function of collecting sensory information regarding bolus viscosity (resistance to flow). In this study, we explored the impact of age-related reductions in tongue strength on oral viscosity discrimination acuity. The experiment employed a triangle test discrimination protocol with an array of xanthan-gum thickened liquids in the mildly to moderately thick consistency range. A sample of 346 healthy volunteers was recruited, with age ranging from 12 to 86 (164 men, 182 women). On average, participants were able to detect a 0.29-fold increase in xanthan-gum concentration, corresponding to a 0.5-fold increase in viscosity at 50/s. Despite having significantly reduced tongue strength on maximum isometric tongue-palate pressure tasks, and regardless of sex, older participants in this study showed no reductions in viscosity discrimination acuity. In this article, the relationship between tongue strength and the ability to discriminate small differences in liquid viscosity during oral processing is explored. Given that tongue strength declines with age in healthy adults and is also reduced in individuals with dysphagia, it is interesting to determine whether reduced tongue strength might contribute to difficulties in evaluating liquid viscosity during the oral stage of swallowing. Using an array of mildly to moderately thick xanthan-gum thickened liquids, this experiment failed to find any evidence that reductions in tongue strength influence oral viscosity discrimination acuity. © 2017 Wiley Periodicals, Inc.

  15. Using Strengthsfinder to Identify Relationships between Marketing Graduate Strengths and Career Outcomes

    Science.gov (United States)

    Tomkovick, Chuck; Swanson, Scott

    2014-01-01

    The present study seeks to better understand how marketing graduates' strengths, and utilization of those strengths in the workplace, may be associated with a variety of academic and career outcomes. Respondents completed two different questionnaires. Findings suggest that marketing graduates whose strengths are not being utilized with their work…

  16. Leg strength and lean mass symmetry influences kicking performance in Australian football.

    Science.gov (United States)

    Hart, Nicolas H; Nimphius, Sophia; Spiteri, Tania; Newton, Robert U

    2014-01-01

    Differential loading patterns during game-based participation may produce or exacerbate strength imbalances between the lower limbs. It is currently unknown whether such imbalances are functionally beneficial or detrimental to performance. This study assessed the influence of lower limb strength and lean mass symmetry on kicking accuracy in Australian Football. Thirty-one Australian footballers were required to perform a kicking assessment, producing ten drop punt kicks over twenty metres to a player target. Athletes were subsequently separated into accurate (n = 15) and inaccurate (n = 16) groups, with lower-body lean mass assessed using whole body DXA scans, and lower-body strength assessed using an isometric protocol. Accurate kickers demonstrated significantly higher relative lean mass (~8% to 16%; p = 0. 001 to 0.004) and significantly lower relative fat mass (~21% to 40%; p = 0.001 to 0.024) than inaccurate kickers. Accurate kickers did not contain any significant difference in lean mass or unilateral strength between lower limbs. Inaccurate kickers displayed significant asymmetry in lean mass (~3%; p ≤ 0.003), producing significant imbalances in strength (~8%; p ≤ 0.002) highlighting a deficiency in their support leg. Greater relative strength and improved lower limb symmetry in strength and muscularity could increase the capacity of an athlete to be technically proficient in favour of greater accuracy. Key PointsStrength deficits in the support leg may lead to inaccurate kicking outcomes.An asymmetry of 3% in lean mass generated an 8% imbalance in leg strength.Greater levels of relative lower-body strength and muscle mass are associated with improved kicking accuracy performance.

  17. Long-term outcome of muscle strength in ulnar and median nerve injury: Comparing manual muscle strength testing, grip and pinch strength dynamometers and a new intrinsic muscle strength dynamometer

    NARCIS (Netherlands)

    A.R. Schreuders (Ton); M.E. Roebroeck (Marij); J.B. Jaquet (Jean); S.E.R. Hovius (Steven); H.J. Stam (Henk)

    2004-01-01

    textabstractObjective: To compare the outcome of muscle strength with manual muscle strength testing grip and pinch strength measurements and a dynamometer which allows for measurements of the intrinsic muscles of the hand in isolation (the Rotterdam Intrinsic Hand Myometer, RIHM). Methods:

  18. Influence of Compositional Variations on Floc Size and Strength

    Science.gov (United States)

    Yin, H.; Tan, X.; Reed, A. H.; Furukawa, Y.; Zhang, G.

    2010-12-01

    Clay-biopolymer micro aggregates or flocs are abundant in waters, including rivers, lakes, and oceans. Owing to their small size and charged surfaces, fine-grained inorganic sediment particles, mainly clays, interact actively with organic substances, such as organic matter and biogenic polymers, to form aggregates or flocs, typically in the size of 10-1000 μm. The flocs in ocean waters are also termed “marine snow”. These flocs are typically porous, tenuous, and soft in nature. During transport in suspension, they may breakdown and decrease in size if the turbulent shear stress exceeds their strength. They may also collide and form larger ones if the shear stress is relatively small. Since flocs of different size and structure settle at different velocities, understanding their strength is also of essential importance for sediment hydrodynamics, transport, and management. Our study focuses on investigating the influence of compositional variations on floc size and strength so that a better understanding of floc dynamics can be achieved. A laser diffraction-based Cilas® particle size and shape analyzer with controllable fluid circulation velocity was employed to conduct floc size measurements and shape imaging, the latter achieved by a high resolution inverted optical microscope, which is also installed with the size analyzer. Totally two clay minerals, kaolinite and illite, were tested as the model inorganic solid skeleton minerals for floc formation, and two biopolymers, anionic xanthan gum and neutral guar gum, were chosen as analogs of naturally occurring organic matter or biopolymers to simulate clay-biopolymer floc formation. Moreover, the concentration of both organic and inorganic phases was varied. The floc breakage or tensile strength was indirectly estimated by the varied fluid flow velocity in the particle size analyzer’s circulation system. For each individual composition, stable flocs were formed by three different fluid circulating velocities

  19. How the global layout of the mask influences masking strength.

    Science.gov (United States)

    Ghose, Tandra; Hermens, Frouke; Herzog, Michael H

    2012-12-10

    In visual backward masking, the perception of a target is influenced by a trailing mask. Masking is usually explained by local interactions between the target and the mask representations. However, recently it has been shown that the global spatial layout of the mask rather than its local structure determines masking strength (Hermens & Herzog, 2007). Here, we varied the mask layout by spatial, luminance, and temporal cues. We presented a vernier target followed by a mask with 25 elements. Performance deteriorated when the length of the two mask elements neighboring the target vernier was doubled. However, when the length of every second mask element was doubled, performance improved. When the luminance of the neighboring elements was doubled, performance also deteriorated but no improvement in performance was observed when every second element had a double luminance. For temporal manipulations, a complex nonmonotonic masking function was observed. Hence, changes in the mask layout by spatial, luminance, and temporal cues lead to highly different results.

  20. Factors influencing the creep strength of hot pressed beryllium

    International Nuclear Information System (INIS)

    Webster, D.; Crooks, D.D.

    1975-01-01

    The parameters controlling the creep strength of hot pressed beryllium block have been determined. Creep strength was improved by a high initial dislocation density, a coarse grain size, and a low impurity content. The impurities most detrimental to creep strength were found to be aluminum, magnesium, and silicon. A uniform distribution of BeO was found to give creep strength which was inferior to a grain boundary distribution. The creep strength of very high purity, hot isostatically pressed beryllium was found to compare favorably with that of other more commonly used high temperature metals

  1. Influence of Cryotherapy on muscle strength: A Literaturae Review

    Directory of Open Access Journals (Sweden)

    Gilvaney Gomes Pereira

    2013-01-01

    Full Text Available The objective of this study was to verify the behavior of muscle strength before cryotherapy use through a literature review. To write this review it was performed the analysis of works with descriptive-analytical approach about the interference of cryotherapy in the muscle strength, and the total of the studies collected was 15. After analysis of collected studies of scientific sources it was verified that there were controversies in the researches found about the muscle strength increased or reduction. It is necessary to conduct new studies that will elucidate physiological effects of ice on the muscle strength.

  2. INFLUENCE OF CRYOTHERAPY ON MUSCLE STRENGTH: A LITERATURE REVIEW

    Directory of Open Access Journals (Sweden)

    Gilvaney Gomes Pereira

    2013-01-01

    Full Text Available The objective of this study was to verify the behavior of muscle strength before cryotherapy use through a literature review. To write this review it was performed the analysis of works with descriptive-analytical approach about the interference of cryotherapy in the muscle strength, and the total of the studies collected was 15. After analysis of collected studies of scientific sources it was verified that there were controversies in the researches found about the muscle strength increased or reduction. It is necessary to conduct new studies that will elucidate physiological effects of ice on the muscle strength.

  3. Influence of paternal age on perinatal outcomes.

    Science.gov (United States)

    Hurley, Emily G; DeFranco, Emily A

    2017-11-01

    There is an increasing trend to delay childbearing to advanced parental age. Increased risks of advanced maternal age and assisted reproductive technologies are widely accepted. There are limited data regarding advanced paternal age. To adequately counsel patients on risk, more research regarding advanced paternal age is necessary. We sought to determine the influence of paternal age on perinatal outcomes, and to assess whether this influence differs between pregnancies achieved spontaneously and those achieved with assisted reproductive technology. A population-based retrospective cohort study of all live births in Ohio from 2006 through 2012 was completed. Data were evaluated to determine if advanced paternal age is associated with an increased risk of adverse outcomes in pregnancies. The analysis was stratified by status of utilization of assisted reproductive technology. Generalized linear regression models assessed the association of paternal age on pregnancy complications in assisted reproductive technology and spontaneously conceived pregnancies, after adjusting for maternal age, race, multifetal gestation, and Medicaid status, using Stata software (Stata, Release 12; StataCorp, College Station, TX). Paternal age was documented in 82.2% of 1,034,552 live births in Ohio during the 7-year study period. Paternal age ranged from 12-87 years, with a median of 30 (interquartile range, 26-35) years. Maternal age ranged from 11-62 years, with a median of 27 (interquartile range, 22-31) years. The use of assisted reproductive technology in live births increased as paternal age increased: 0.1% 60 years, P risk factors, increased paternal age was not associated with a significant increase in the rate of preeclampsia, preterm birth, fetal growth restriction, congenital anomaly, genetic disorder, or neonatal intensive care unit admission. The influence of paternal age on pregnancy outcomes was similar in pregnancies achieved with and without assisted reproductive

  4. Side effects as influencers of treatment outcome.

    Science.gov (United States)

    Sharif, Zafar

    2008-01-01

    Research relative to the efficacy of a therapeutic agent commands a clinician's greatest interest, but treatment decisions are made based on optimizing efficacy and tolerability/safety considerations. Second-generation atypical antipsychotic drugs are a study in the importance of taking a careful look at the full benefit-risk profile of each drug. The disorders that atypical antipsychotics are approved to treat--schizophrenia, schizoaffective disorder, and bipolar disorder--are associated with an increased rate of certain medical comorbidities compared to the general population. Between-drug differences in efficacy are relatively modest for the atypicals, or between atypicals and conventionals, while differences in safety and tolerability are larger and more clinically relevant. The current article will provide a brief summary of safety-related issues that influence treatment outcome and choice of drug.

  5. Influence of physical activity on vertebral strength during late adolescence.

    Science.gov (United States)

    Junno, Juho-Antti; Paananen, Markus; Karppinen, Jaro; Tammelin, Tuija; Niinimäki, Jaakko; Lammentausta, Eveliina; Niskanen, Markku; Nieminen, Miika T; Järvelin, Marjo-Riitta; Takatalo, Jani; Tervonen, Osmo; Tuukkanen, Juha

    2013-02-01

    Reduced vertebral strength is a clear risk factor for vertebral fractures. Men and women with vertebral fractures often have reduced vertebral size and bone mineral density (BMD). Vertebral strength is controlled by both genetic and developmental factors. Malnutrition and low levels of physical activity are commonly considered to result in reduced bone size during growth. Several studies have also demonstrated the general relationship between BMD and physical activity in the appendicular skeleton. In this study, we wanted to clarify the role of physical activity on vertebral bodies. Vertebral dimensions appear to generally be less pliant than long bones when lifetime changes occur. We wanted to explore the association between physical activity during late adolescence and vertebral strength parameters such as cross-sectional size and BMD. The association between physical activity and vertebral strength was explored by measuring vertebral strength parameters and defining the level of physical activity during adolescence. The study population consisted of 6,928 males and females who, at 15 to 16 and 19 years of age, responded to a mailed questionnaire inquiring about their physical activity. A total of 558 individuals at the mean age of 21 years underwent magnetic resonance imaging (MRI) scans. We measured the dimensions of the fourth lumbar vertebra from the MRI scans of the Northern Finland Birth Cohort 1986 and performed T2* relaxation time mapping, reflective of BMD. Vertebral strength was based on these two parameters. We analyzed the association of physical activity on vertebral strength using the analysis of variance. We observed no association between the level of physical activity during late adolescence and vertebral strength at 21 years. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Influence of the welding process on martensitic high strength steel

    Directory of Open Access Journals (Sweden)

    Petr Hanus

    2014-07-01

    Full Text Available The subject of the study is martensitic 22MnB5 steels, which are used in the automotive industry. The main purpose of the performed analyses is a study of strength differences in heat affected zones of the spot welding. For the needs of the strength decrease assessment, the critical layer of the heat affected area was experimentally simulated. The aim of the work is to determine the most suitable methodology for evaluating the local changes of the elastic-plastic material response. The aim of this work is to determine the optimal methods for the determination of the yield strength and to find a firming trend in these zones.

  7. Influence of Binding Rates on Strength Properties of Moulding Sands with the GEOPOL Binder

    Directory of Open Access Journals (Sweden)

    Holtzer M.

    2014-03-01

    Full Text Available The results of investigations of moulding sands with an inorganic binder called GEOPOL, developed by the SAND TEAM Company are presented in the paper. Hardeners of various hardening rates are used for moulding sands with this binder. The main aim of investigations was determination of the influence of the hardening rate of moulding sands with the GEOPOL binder on technological properties of these sands (bending strength, tensile strength, permeability and grindability. In addition, the final strength of moulding sands of the selected compositions was determined by two methods: by splitting strength and shear strength measurements. No essential influence of the hardening rate on such parameters as: permeability, grindability and final strength was found. However, the sand in which the slowest hardener (SA 72 were used, after 1 hour of holding, had the tensile and bending strength practically zero. Thus, the time needed for taking to pieces the mould made of such moulding sand will be 1.5 - 2 hours.

  8. Influence of strength training on cardiac risk prevention in ...

    African Journals Online (AJOL)

    It has widely been shown that exercise, particularly aerobic exercise, has extensive cardioprotective benefits and is an important tool in the prevention of coronary heart disease (CHD). The present investigation aimed to determine the multivariate impact of strength training, designed to prevent the development of CHD, on ...

  9. Influence of irradiation on high-strength graphites

    International Nuclear Information System (INIS)

    Virgil'ev, Yu.S.; Grebennik, V.N.; Kalyagina, I.P.

    1989-01-01

    To ensure efficiency of the graphite elements of the construction of the masonry of reactors, the graphite must possess high radiation stability, strength, and heat resistance. In this connection, the physical properties of graphites based on uncalcined petroleum coke with a binder - high-temperature hard coal pitch - the amount of which reaches 40% are considered in this paper

  10. Influence of curing regimes on compressive strength of ultra high

    Indian Academy of Sciences (India)

    The present paper is aimed to identify an efficient curing regime for ultra high performance concrete (UHPC), to achieve a target compressive strength more than 150 MPa, using indigenous materials. The thermal regime plays a vital role due to the limited fineness of ingredients and low water/binder ratio. By activation of the ...

  11. System effects influencing the bending strength of timber beams

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager; Källsner, B.

    1998-01-01

    A stochastic model of hierarchical series system type for the bending strength of spruce beams isdefined from the anticipation that the bending failure takes place at a cross-section with a defect cluster formed by knots or grain irregularities. The parameters of the model are estimated from meas...

  12. The Influence of Forward and Backward Associative Strength on False Memories for Encoding Context

    Science.gov (United States)

    Arndt, Jason

    2016-01-01

    Two experiments examined the effects of Forward Associative Strength (FAS) and Backward Associative Strength (FAS) on false recollection of unstudied lure items. Themes were constructed such that four associates were strongly related to a lure item in terms of FAS or BAS and four associates were weakly related to a lure item in terms of FAS or BAS. Further, when FAS was manipulated, BAS was controlled across strong and weak associates, while FAS was controlled across strong and weak associates when BAS was manipulated. Strong associates were presented in one font while weak associates were presented in a second font. At test, lure items were disproportionately attributed to the source used to present lures’ strong associates compared to lures’ weak associates, both when BAS was manipulated and when FAS was manipulated. This outcome demonstrates that both BAS and FAS influence lure item false recollection, which favors global-matching models’ explanation of false recollection over the explanation offered by spreading-activation theories. PMID:25312499

  13. Joint-Angle Specific Strength Adaptations Influence Improvements in Power in Highly Trained Athletes

    Directory of Open Access Journals (Sweden)

    Rhea Matthew R.

    2016-03-01

    Full Text Available Purpose. The purpose of this study was to examine the influence of training at different ranges of motion during the squat exercise on joint-angle specific strength adaptations. Methods. Twenty eight men were randomly assigned to one of three training groups, differing only in the depth of squats (quarter squat, half squat, and full squat performed in 16-week training intervention. Strength measures were conducted in the back squat pre-, mid-, and post-training at all three depths. Vertical jump and 40-yard sprint time were also measured. Results. Individuals in the quarter and full squat training groups improved significantly more at the specific depth at which they trained when compared to the other two groups (p < 0.05. Jump height and sprint speed improved in all groups (p < 0.05; however, the quarter squat had the greatest transfer to both outcomes. Conclusions. Consistently including quarter squats in workouts aimed at maximizing speed and jumping power can result in greater improvements.

  14. The influence of main bar corrosion on bond strength in selfcompacting concrete

    Science.gov (United States)

    Ayop, S. S.; Emhemed, A. N. K.; Jamaluddin, N.; Sadikin, A.

    2017-11-01

    The experimental study was conducted to determine the influence of main bar corrosion on bond strength in self-compacting concrete (SCC). A total 16 tension pullout tests specimens reinforced with 10 mm and 14 mm diameter bar were used for the bond strength test. The properties of SCC were determined from the slump flow, T50cm, V-funnel and L box test. Reinforcing bars in the concrete were submitted to impressed current to accelerate the corrosion of the bar. It was found that the relationship between bond strength and concrete strength in un-corroded specimens differed from that of corroded specimens set in high-strength concrete because of brittleness in the corroded specimens, which caused a sudden loss of bond strength. The results revealed that specimens of un-corroded and corroded showed a higher percentage of bond strength degradation during the pullout tests.

  15. The influence of stretching on tensile strength and solubility of poly(vinyl alcohol) fibres

    NARCIS (Netherlands)

    Heikens, D.; Bleijenberg, A.C.A.M.; Hoppenbrouwers, J.J.M.; Barentsen, W.M.

    1971-01-01

    The strength of wet-spun poly(vinyl alcohol) (pva) fibres is given as function of bath-stretching, wet-stretching and hot-stretching. In the two equations derived for strength of wet-stretching and hot-stretching the complex influence of the bath-stretching and hot-stretching is demonstrated. The

  16. Baseline strength can influence the ability of salivary free testosterone to predict squat and sprinting performance.

    Science.gov (United States)

    Crewther, Blair T; Cook, Christian J; Gaviglio, Chris M; Kilduff, Liam P; Drawer, Scott

    2012-01-01

    The objective of this study was to determine if salivary free testosterone can predict an athlete's performance during back squats and sprints over time and the influence baseline strength on this relationship. Ten weight-trained male athletes were divided into 2 groups based on their 1 repetition maximum (1RM) squats, good squatters (1RM > 2.0 × body weight, n = 5) and average squatters (1RM squat 1RM and 10-m sprint times on 10 separate occasions over a 40-day period. A saliva sample was collected before testing and assayed for free testosterone and cortisol. The pooled testosterone correlations were strong and significant in the good squatters (r = 0.92 for squats, r = -0.87 for sprints, p squats, r = -0.18 for sprints). Cortisol showed no significant correlations with 1RM squat and 10-m sprint performance, and no differences were identified between the 2 squatting groups. In summary, these results suggest that free testosterone is a strong individual predictor of squat and sprinting performance in individuals with relatively high strength levels but a poor predictor in less strong individuals. This information can assist coaches, trainers, and performance scientists working with stronger weight-trained athletes, for example, the preworkout measurement of free testosterone could indicate likely training outcomes or a readiness to train at a certain intensity level, especially if real-time measurements are made. Our results also highlight the need to separate group and individual hormonal data during the repeated testing of athletes with variable strength levels.

  17. Influence of refraction index strength on the light propagation in dielectrics material with periodic refraction index

    International Nuclear Information System (INIS)

    Hidayat, Arif; Latifah, Eny; Kurniati, Diana; Wisodo, Hari

    2016-01-01

    This study investigated the influence of refraction index strength on the light propagation in refraction index-varied dielectric material. This dielectric material served as photonic lattice. The behavior of light propagation influenced by variation of refraction index in photonic lattice was investigated. Modes of the guiding light were determined numerically using squared-operator iteration method. It was found that the greater the strength of refraction index, the smaller the guiding modes.

  18. Strengths, Risk Factors, and Resilient Outcomes in Adolescents With Type 1 Diabetes

    DEFF Research Database (Denmark)

    Hilliard, Marisa E; Hagger, Virginia; Hendrieckx, Christel

    2017-01-01

    OBJECTIVE: Despite the challenges of living with type 1 diabetes, many adolescents achieve "resilient outcomes": high engagement in self-management behaviors such as self-monitoring of blood glucose (SMBG), good quality of life (QOL), and within-target glycemic outcomes (HbA1c). Adaptive diabetes...... factors. RESEARCH DESIGN AND METHODS: A total of 471 Australian adolescents with type 1 diabetes (mean age 15.7 ± 1.9 years; diabetes duration 6.9 ± 4.2 years; 62% female; 53% using insulin pumps) completed a national cross-sectional survey about their diabetes-related strengths, risk factors (depressive....../anxiety symptoms, family conflict), and resilient outcomes (SMBG frequency, general QOL, HbA1c). RESULTS: Greater diabetes strengths were significantly related to resilient outcomes: more frequent SMBG (r = 0.39), lower HbA1c (r = -0.31), and higher general QOL (r = 0.50), as well as to lower risks: fewer...

  19. Social-bond strength influences vocally mediated recruitment to mobbing.

    Science.gov (United States)

    Kern, Julie M; Radford, Andrew N

    2016-11-01

    Strong social bonds form between individuals in many group-living species, and these relationships can have important fitness benefits. When responding to vocalizations produced by groupmates, receivers are expected to adjust their behaviour depending on the nature of the bond they share with the signaller. Here we investigate whether the strength of the signaller-receiver social bond affects response to calls that attract others to help mob a predator. Using field-based playback experiments on a habituated population of wild dwarf mongooses (Helogale parvula), we first demonstrate that a particular vocalization given on detecting predatory snakes does act as a recruitment call; receivers were more likely to look, approach and engage in mobbing behaviour than in response to control close calls. We then show that individuals respond more strongly to these recruitment calls if they are from groupmates with whom they are more strongly bonded (those with whom they preferentially groom and forage). Our study, therefore, provides novel evidence about the anti-predator benefits of close bonds within social groups. © 2016 The Author(s).

  20. Influence of dunite mineral additive on strength of cement

    Science.gov (United States)

    Vasilyeva, A. A.; Moskvitina, L. V.; Moskvitin, S. G.; Lebedev, M. P.; Fedorova, G. D.

    2017-12-01

    The work studies the applicability of dunite rocks from Inagli massif (South Yakutia) for the production of mixed (composite) cement. The paper reviews the implementation of dunite for manufacturing materials and products. The chemical and mineral compositions of Inagli massif dunite rocks are presented, which relegate the rocks to magnesia-silicate rocks of low-quality in terms of its application as refractory feedstock due to appreciable serpentinization of dunite. The work presents the results of dunite study in terms of its applicability as an additive to Portland cement. The authors have established that dunite does not feature hydraulicity and can be used as a filling additive to Portland cement in the amount of up to 40%. It was unveiled that the mixed grinding of Portland cement and dunite sand with specific surface area of 5500 cm2/g yields the cement that complies with GOST 31108-2016 for CEM II and CEM V normal-cured cements with strength grades of 32.5 and 42.5. The work demonstrates the benefits of the studies of dunite as a filling additive for producing both Portland cement with mineral component and composite (mixed) cement.

  1. Strength, body composition, and functional outcomes in the squat versus leg press exercises.

    Science.gov (United States)

    Rossi, Fabrício E; Schoenfeld, Brad J; Ocetnik, Skyler; Young, Jonathan; Vigotsky, Andrew; Contreras, Bret; Krieger, James W; Miller, Michael G; Cholewa, Jason

    2018-03-01

    The purpose of this study was to compare strength, body composition, and functional outcome measures following performance of the back squat, leg press, or a combination of the two exercises. Subjects were pair-matched based on initial strength levels and then randomly assigned to 1 of 3 groups: a squat-only group (SQ) that solely performed squats for the lower body; a leg press-only group (LP) that solely performed leg presses for the lower body, or a combined squat and leg press group (SQ-LP) that performed both squats and leg presses for the lower body. All other RT variables were held constant. The study period lasted 10 weeks with subjects performing 2 lower body workouts per week comprising 6 sets per session at loads corresponding to 8-12 RM with 90- to 120-second rest intervals. Results showed that SQ had greater transfer to maximal squat strength compared to the leg press. Effect sizes favored SQ and SQ-LP versus LP with respect to countermovement jump while greater effect sizes for dynamic balance were noted for SQ-LP and LP compared to SQ, although no statistical differences were noted between conditions. These findings suggest that both free weights and machines can improve functional outcomes, and that the extent of transfer may be specific to the given task.

  2. Prognostic indicators influencing short term outcomes among ...

    African Journals Online (AJOL)

    Background: Head injury causes significant morbidity and mortalityand accounts for about 10 million cases globally. In Tanzaniait's the most common type of injury contributing about 32% to 50% of all trauma patients. Favorable outcomes for head injury patients depends on initial evaluation and proper timely intervention.

  3. Influence of cracks and pitting corrosion on residual ultimate strength of stiffened plates

    Directory of Open Access Journals (Sweden)

    ZHANG Jing

    2018-02-01

    Full Text Available [Objectives] Ships and offshore platforms serve in the harsh sea environment for a long time. Cracks and pitting corrosion will occur in such a structure and the damage will affect its ultimate strength.[Methods] To investigate the influence of cracks and pitting corrosion on ultimate bearing capacity, the ultimate strength of a structure under axial compression is studied by using a nonlinear finite element. The mesh size of a stiffened plate with cracks and pitting corrosion is first discussed. Then the influence of the relative positions of cracks and pitting corrosion, number of corrosion points and crack length impact on the residual ultimate strength of damaged stiffened plates is discussed via a series of calculations.[Results] The results indicate that the increase in crack length and pitting corrosion significantly decreases the ultimate strength of a stiffened plate. [Conclusions] This provides a useful reference for designing and maintaining ships and offshore structures in their life cycles.

  4. Investigating combined influence of petrology and technological parameters on strength of porous coke body

    Energy Technology Data Exchange (ETDEWEB)

    Dinel' t, V.M.; Shkoller, M.B.; Stankevich, A.S.; Korchuganova, G.S.

    1983-09-01

    The VUKhIN branch in Kuznetsk investigated effects of coal petrology and coking conditions on structural strength of coke in blast furnaces. Structural strength of coke produced from black coal from the Kuzbass as well as structural strength of coke partially gasified by carbon dioxide under conditions similar to those in blast furnaces was investigated. Fourteen samples of coal mixtures from the Kuzbass were used. Regression analysis was applied. Equations for forecasting coke properties on the basis of coal petrology and selected parameters characterizing coking were derived. Analyses showed that coke structural strength was decisively influenced by coefficients which characterized the average reflectivity of vitrinite in a coal mixture and its average density. After partial coke gasification by carbon dioxide effects of coefficients which characterized coal mixture nonhomogeneity (fluctuations of vitrinite reflectivity) and coal mixture density increased. Increasing coal density partially compensated negative effects of fluctuations of vitrinite reflectivity on coke structural strength. (10 refs.) (In Russian)

  5. On the influence of load variations on lifetime and strength of wood

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    2006-01-01

    To days recommendations for probability and reliability analysis of wood structures do not fully recognize the influence of wood microstructure and creep on the mechanical behavior of wood. As a consequence, certain important features in wood design cannot be considered properly. Ignoring the bas...... history on recycle-strength (residual strength). It is demonstrated in this paper, how the problems just mentioned can be solved from respecting wood as a damaged viscoelastic material, meaning that wood is a cracked (damaged) material with creep....

  6. The Influence of Creatine Monohydrate on Strength and Endurance After Doing Physical Exercise With Maximum Intensity

    Directory of Open Access Journals (Sweden)

    Asrofi Shicas Nabawi

    2017-11-01

    Full Text Available The purpose of this study was: (1 to analyze the effect of creatine monohydrate to give strength after doing physical exercise with maximum intensity, towards endurance after doing physical exercise with maximum intensity, (2 to analyze the effect of non creatine monohydrate to give strength after doing physical exercise with maximum intensity, towards endurance after doing physical exercise with maximum intensity, (3 to analyze the results of the difference by administering creatine and non creatine on strength and endurance after exercise with maximum intensity. This type of research used in this research was quantitative with quasi experimental research methods. The design of this study was using pretest and posttest control group design, and data analysis was using a paired sample t-test. The process of data collection was done with the test leg muscle strength using a strength test with back and leg dynamometer, sit ups test with 1 minute sit ups, push ups test with push ups and 30 seconds with a VO2max test cosmed quart CPET during the pretest and posttest. Furthermore, the data were analyzed using SPSS 22.0 series. The results showed: (1 There was the influence of creatine administration against the strength after doing exercise with maximum intensity; (2 There was the influence of creatine administration against the group endurance after doing exercise with maximum intensity; (3 There was the influence of non creatine against the force after exercise maximum intensity; (4 There was the influence of non creatine against the group after endurance exercise maximum intensity; (5 The significant difference with the provision of non creatine and creatine from creatine group difference delta at higher against the increased strength and endurance after exercise maximum intensity. Based on the above analysis, it can be concluded that the increased strength and durability for each of the groups after being given a workout.

  7. Does progressive resistance strength training as additional training have any measured effect on functional outcomes in older hospitalized patients?

    DEFF Research Database (Denmark)

    Tibaek, Sigrid; Andersen, Christina W.; Pedersen, Sigrid F

    2014-01-01

    OBJECTIVE: To evaluate the effect of progressive resistance strength training as additional training measured on functional outcomes in older hospitalized patients. DESIGN: A single-blinded randomized controlled trial. SETTING: Department of Geriatric Rehabilitation in university hospital...

  8. Does gender influence outcomes in critically ill patients?

    OpenAIRE

    Angele, Martin K; Pratschke, Sebastian; Chaudry, Irshad H

    2012-01-01

    Investigators continue to debate whether gender plays any role in patient outcome following injury/critical illness. We submit that age and hormonal milieu at the time of injury, rather than gender, are the critical factors influencing patient outcome under those conditions.

  9. Infertility and Weight Reduction: Influence and Outcome

    International Nuclear Information System (INIS)

    Khaskheli, M. N.; Baloch, S.; Baloch, A. S.

    2013-01-01

    Objective: To assess the effect of weight reduction in obese infertile women on conception rate spontaneously as well as with ovulation induction and pregnancy outcome. Study Design: Observational experimental study. Place and Duration of Study: Different private clinics at Mirpurkhas, Thana Bola Khan and Hyderabad, Sindh, Pakistan, from March 2008 to February 2011. Methodology: Infertile women who were obese with the body mass index (BMI) > 30 kg/ m2 and failed to conceive within 2-5 years after taking treatment of infertility for many cycles were inducted. These women underwent life style change program related to exercise and diet for 6 months and in the next 6 months they were observed for spontaneous conception. Those women who failed to conceive were prescribed ovulation induction (clomifene citrate) for the next 6 months and were observed for conception. After conception, they visited regularly during antenatal period till delivery. The data was collected and analyzed on SPSS version 17. Results: The mean decrease in the body index observed was 9.6 +- 1.23 kg/m2, spontaneous conception rate was (n = 35, 41.17%) and miscarriage rate was (n = 9, 16.66%). Conclusion: Weight reduction leads to high spontaneous conception rate as well as with ovulation induction therapy and improves the pregnancy outcome. (author)

  10. The influence of annealing temperature on the strength of TRISO coated particles

    Energy Technology Data Exchange (ETDEWEB)

    Rooyen, I.J. van, E-mail: Isabel.vanrooyen@pbmr.co.z [Pebble Bed Modular Reactor (Pty) Ltd., 1279 Mike Crawford Avenue, Centurion (South Africa); Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Neethling, J.H. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Rooyen, P.M. van [Pebble Bed Modular Reactor (Pty) Ltd., 1279 Mike Crawford Avenue, Centurion (South Africa)

    2010-07-31

    The integrity of the Pebble Bed Modular Reactor (PBMR) fuel, and specifically the SiC layer system of the Tristructural Isotropic (TRISO) coated particle (CP), namely inner pyrolytic carbon, silicon carbide and outer pyrolytic carbon (I-PyC-SiC-O-PyC), determines the containment of fission products. The PBMR fuel consists of TRISO coated particles (CPs) embedded in a graphite matrix. One of the characterization techniques investigated by PBMR is the determination of strength of CPs. It is a well known metallurgical fact that temperature, amongst many other parameters, may influence the strength of a material. A recently developed method for measuring the strength of the TRISO coated particles was used and is briefly described in this article. The advantages of this method are demonstrated by the comparison of strength measurements of five experimental PBMR CP batches as a function of annealing temperature. Significant modification of strength after annealing was measured with increased temperature within the range 1000-2100 {sup o}C. The interesting feature of decreasing standard deviation of the strength with increasing temperature will also be discussed with a possible explanation. A significant difference in coated particle strength is also demonstrated for two CP batches with layer thickness on the extremities of the SiC layer thickness specification. The effect of long duration annealing on these strength values will also be demonstrated by comparing results from 1 h to 100 h annealing periods of coated particles at a temperature of 1600 {sup o}C.

  11. The influence of annealing temperature on the strength of TRISO coated particles

    International Nuclear Information System (INIS)

    Rooyen, I.J. van; Neethling, J.H.; Rooyen, P.M. van

    2010-01-01

    The integrity of the Pebble Bed Modular Reactor (PBMR) fuel, and specifically the SiC layer system of the Tristructural Isotropic (TRISO) coated particle (CP), namely inner pyrolytic carbon, silicon carbide and outer pyrolytic carbon (I-PyC-SiC-O-PyC), determines the containment of fission products. The PBMR fuel consists of TRISO coated particles (CPs) embedded in a graphite matrix. One of the characterization techniques investigated by PBMR is the determination of strength of CPs. It is a well known metallurgical fact that temperature, amongst many other parameters, may influence the strength of a material. A recently developed method for measuring the strength of the TRISO coated particles was used and is briefly described in this article. The advantages of this method are demonstrated by the comparison of strength measurements of five experimental PBMR CP batches as a function of annealing temperature. Significant modification of strength after annealing was measured with increased temperature within the range 1000-2100 o C. The interesting feature of decreasing standard deviation of the strength with increasing temperature will also be discussed with a possible explanation. A significant difference in coated particle strength is also demonstrated for two CP batches with layer thickness on the extremities of the SiC layer thickness specification. The effect of long duration annealing on these strength values will also be demonstrated by comparing results from 1 h to 100 h annealing periods of coated particles at a temperature of 1600 o C.

  12. Influence of adhesion promoters and curing-light sources on the shear bond strength of orthodontic brackets

    Directory of Open Access Journals (Sweden)

    Claudia Tavares Machado

    2012-01-01

    Conclusions: The conventional orthodontic adhesive presented higher bond strength than the nanofilled composite, although both materials interacted similarly to the teeth. The curing-light devices tested did not influence on bond strength of orthodontic brackets.

  13. Influence of bottom ash of palm oil on compressive strength of concrete

    Science.gov (United States)

    Saputra, Andika Ade Indra; Basyaruddin, Laksono, Muhamad Hasby; Muntaha, Mohamad

    2017-11-01

    The technological development of concrete demands innovation regarding the alternative material as a part of the effort in improving quality and minimizing reliance on currently used raw materials such as bottom ash of palm oil. Bottom ash known as domestic waste stemming from palm oil cultivation in East Kalimantan contains silica. Like cement in texture and size, bottom ash can be mixed with concrete in which the silica in concrete could help increase the compressive strength of concrete. This research was conducted by comparing between normal concrete and concrete containing bottom ash as which the materials were apart of cement replacement. The bottom ash used in this research had to pass sieve size (#200). The composition tested in this research involved ratio between cement and bottom ash with the following percentages: 100%: 0%, 90%: 10%, 85%: 15% and 80%: 20%. Planned to be within the same amount of compressive strength (fc 25 MPa), the compressive strength of concrete was tested at the age of 7, 14, and 28 days. Research result shows that the addition of bottom ash to concrete influenced workability in concrete, but it did not significantly influence the compressive strength of concrete. Based on the result of compressive strength test, the optimal compressive strength was obtained from the mixture of 100% cement and 0% bottom ash.

  14. Risk factors influencing the treatment outcome in diabetic macular oedema

    Directory of Open Access Journals (Sweden)

    Gupta Amod

    1996-01-01

    Full Text Available A multivariate analysis was done on 96 eyes to evaluate the effect of various risk factors on the final visual outcome after laser photocoagulation for clinically significant macular oedema (CSME in diabetic retinopathy. Advanced age of the patient, large size of CSME and poor baseline visual acuity were found to be significantly associated with poorer outcome (p<0.05. The association of nephropathy and hypertension with poorer visual outcome was of boderline significance (p = 0.054 and 0.07, respectively. Wavelength of the laser (argon or krypton used for treatment did not significantly influence the outcome.

  15. The influence of chromosome density variations on the increase in nuclear disorder strength in carcinogenesis

    International Nuclear Information System (INIS)

    Kim, Jun Soo; Pradhan, Prabhakar; Backman, Vadim; Szleifer, Igal

    2011-01-01

    Microscopic structural changes have long been observed in cancer cells and used as a marker in cancer diagnosis. Recent development of an optical technique, partial-wave spectroscopy (PWS), enabled more sensitive detection of nanoscale structural changes in early carcinogenesis in terms of the disorder strength related to density variations. These nanoscale alterations precede the well-known microscopic morphological changes. We investigate the influence of nuclear density variations due to chromosome condensation on changes of disorder strength by computer simulations of model chromosomes. Nuclear configurations with different degrees of chromosome condensation are realized from simulations of decondensing chromosomes and the disorder strength is calculated for these nuclear configurations. We found that the disorder strength increases significantly for configurations with slightly more condensed chromosomes. Coupled with PWS measurements, the simulation results suggest that the chromosome condensation and the resulting spatial density inhomogeneity may represent one of the earliest events in carcinogenesis

  16. Shear bond strength of one-step self-etch adhesives: pH influence

    Science.gov (United States)

    Poggio, Claudio; Beltrami, Riccardo; Scribante, Andrea; Colombo, Marco; Chiesa, Marco

    2015-01-01

    Background: The aim of this study was to compare the shear bond strength of four one-step self-etch adhesives with different pH values to enamel and dentin. Materials and Methods: In this in vitro study, 200 bovine permanent mandibular incisors were used. Four one-step self-etch adhesives with different pH values were tested both on enamel and on dentin: Adper™ Easy Bond Self-Etch Adhesive (pH = 0.8-1), Futurabond NR (pH=2), G-aenial Bond (pH = 1.5), Clearfil S3 Bond (pH = 2.7). After adhesive systems application, a nanohybrid composite resin was inserted into the bonded surface. The specimens were placed in a universal testing machine. The shear bond strength was performed at a cross-head speed of 1 mm/min until the sample rupture. The shear bond strength values (MPa) of the different groups were compared with analysis of variance after that Kolmogorov and Smirnov tests were applied to assess normality of distributions. P enamel shear bond strength, the highest shear bond strength values were reported with Futurabond NR (P adhesive systems showed lower shear bond strength values with significant differences between them (P 0.05). Conclusion: The pH values of adhesive systems did not influence significantly their shear bond strength to enamel or dentin. PMID:26005459

  17. Constraining is enabling? Exploring the influence of national context on civil society strength

    NARCIS (Netherlands)

    Kamstra, J.; Pelzer, B.J.; Elbers, W.J.; Ruben, R.

    2016-01-01

    This article analyses the influence of national context on civil society strength based on four key dimensions: level of democracy, political stability, rule of law and economic development. Whereas existing studies mainly focus on Western and post-communist countries, we explicitly include

  18. Constraining Is Enabling? Exploring the Influence of National Context on Civil Society Strength

    NARCIS (Netherlands)

    Kamstra, Jelmer; Pelzer, Ben; Elbers, Willem; Ruben, Ruerd

    2016-01-01

    This article analyses the influence of national context on civil society strength based on four key dimensions: level of democracy, political stability, rule of law and economic development. Whereas existing studies mainly focus on Western and post-communist countries, we explicitly include

  19. The influence of cooling forearm/hand and gender on estimation of handgrip strength.

    Science.gov (United States)

    Cheng, Chih-Chan; Shih, Yuh-Chuan; Tsai, Yue-Jin; Chi, Chia-Fen

    2014-01-01

    Handgrip strength is essential in manual operations and activities of daily life, but the influence of forearm/hand skin temperature on estimation of handgrip strength is not well documented. Therefore, the present study intended to investigate the effect of local cooling of the forearm/hand on estimation of handgrip strength at various target force levels (TFLs, in percentage of MVC) for both genders. A cold pressor test was used to lower and maintain the hand skin temperature at 14°C for comparison with the uncooled condition. A total of 10 male and 10 female participants were recruited. The results indicated that females had greater absolute estimation deviations. In addition, both genders had greater absolute deviations in the middle range of TFLs. Cooling caused an underestimation of grip strength. Furthermore, a power function is recommended for establishing the relationship between actual and estimated handgrip force. Statement of relevance: Manipulation with grip strength is essential in daily life and the workplace, so it is important to understand the influence of lowering the forearm/hand skin temperature on grip-strength estimation. Females and the middle range of TFL had greater deviations. Cooling the forearm/hand tended to cause underestimation, and a power function is recommended for establishing the relationship between actual and estimated handgrip force. Practitioner Summary: It is important to understand the effect of lowering the forearm/hand skin temperature on grip-strength estimation. A cold pressor was used to cool the hand. The cooling caused underestimation, and a power function is recommended for establishing the relationship between actual and estimated handgrip force. Manipulation with grip strength is essential in daily life and the workplace, so it is important to understand the influence of lowering the forearm/hand skin temperature on grip-strength estimation. Females and the middle range of TFL had greater deviations. Cooling the

  20. Influence of different etching modes on bond strength and fatigue strength to dentin using universal adhesive systems.

    Science.gov (United States)

    Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Berry, Thomas P; Watanabe, Hedehiko; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

    2016-02-01

    The purpose of this study was to determine the dentin bonding ability of three new universal adhesive systems under different etching modes using fatigue testing. Prime & Bond elect [PE] (DENTSPLY Caulk), Scotchbond Universal [SU] (3M ESPE), and All Bond Universal [AU] (Bisco) were used in this study. A conventional single-step self-etch adhesive, Clearfil Bond SE ONE [CS] (Kuraray Noritake Dental) was also included as a control. Shear bond strengths (SBS) and shear fatigue strength (SFS) to human dentin were obtained in the total-etch mode and self-etch modes. For each test condition, 15 specimens were prepared for the SBS and 30 specimens for SFS. SEM was used to examine representative de-bonded specimens, treated dentin surfaces and the resin/dentin interface for each test condition. Among the universal adhesives, PE in total-etch mode showed significantly higher SBS and SFS values than in self-etch mode. SU and AU did not show any significant difference in SBS and SFS between the total-etch mode and self-etch mode. However, the single-step self-etch adhesive CS showed significantly lower SBS and SFS values in the etch-and-rinse mode when compared to the self-etch mode. Examining the ratio of SFS/SBS, for PE and AU, the etch-and-rinse mode groups showed higher ratios than the self-etch mode groups. The influence of different etching modes on dentin bond quality of universal adhesives was dependent on the adhesive material. However, for the universal adhesives, using the total-etch mode did not have a negative impact on dentin bond quality. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  1. The Influence of Diatomite on the Strength and Microstructure of Portland Cement

    Directory of Open Access Journals (Sweden)

    Liu Jun

    2016-01-01

    Full Text Available To study the influence of the types and mixing amount of diatomite on the Portland cement, we prepared the cement specimen doped with the calcined first-grade, first-grade and second-grade diatomite ,tested the 3d, 7d, 14d compressive strength, and studied and discussed phase, structure and morphology of diatomite in the binary system by the method of XRD, SEM . Experimental results show that with the addition of diatomite, the strength of cement paste increase; the optimal contents of calcined first-grade ,first-grade and second-grade diatomite in Portland cement are 5%,Compared to the blank group, the strength of specimen can be increased by 54.6%, 15.4% and 10.2%, respectively; At the same time ,the 7d microscopic hydration of different diatomite particles were analyzed through the experiment , and the shell of calcined diatomite particles were better hydrated than that of first-grade and second-grade diatomite particles. The results indicate that the diatomite can improve the strength of cement paste, the hydration of different diatomite particles can influence the growth of cement paste strength.

  2. Influence of MSD crack pattern on the residual strength of flat stiffened sheets

    Science.gov (United States)

    Nilsson, K.-F.

    A parameter study of the residual strength for a multiple site damaged (MSD) stiffened sheet is presented. The analysis is based on an elastic-plastic fracture analysis using the yield-strip model for interaction between a lead crack and the smaller MSD cracks. Two crack growth criteria, one with a pronounced crack growth resistance and one with no crack growth resistance and five different MSD crack patterns, are analysed for different sizes of the lead crack and the smaller MSD cracks. The analysis indicates that the residual strength reduction depends on all these parameters and that MSD may totally erode the crack arrest capability of a tear strap. Another important outcome is that for certain combinations also very small MSD cracks may induce a significant residual strength reduction.

  3. Influence of laser cutting on the fatigue limit of two high strength steels

    International Nuclear Information System (INIS)

    Mateo, Antonio; Fargas, Gemma; Calvo, Jessica; Roa, Joan Josep

    2015-01-01

    Laser cutting is widely used in the metal industry, particularly when components of high strength steel sheets are produced. However, the roughness of cut edges produced by laser differs from that obtained by other methods, such as mechanical blanking, and this fact influences the fatigue performance. In the present investigation, specimens of two grades of high strength austenitic steels, i.e. AISI 301LN and TWIP17Mn, were cut by laser and tested in the high cycle fatigue regime to determine their corresponding fatigue limits. A series of fatigue specimens were tested without polishing and other series after a careful polishing of the cut edges, in order to assess the influence of the cut edges condition. Results indicate a significant influence of the edge roughness, more distinctive for AISI 301LN than for TWIP steel.

  4. Influence of laser cutting on the fatigue limit of two high strength steels

    Energy Technology Data Exchange (ETDEWEB)

    Mateo, Antonio; Fargas, Gemma; Calvo, Jessica; Roa, Joan Josep [Univ. Politecnica de Catalunya, Barcelona (Spain). Dept. of Materials Science and Metallurgical Engineering

    2015-02-01

    Laser cutting is widely used in the metal industry, particularly when components of high strength steel sheets are produced. However, the roughness of cut edges produced by laser differs from that obtained by other methods, such as mechanical blanking, and this fact influences the fatigue performance. In the present investigation, specimens of two grades of high strength austenitic steels, i.e. AISI 301LN and TWIP17Mn, were cut by laser and tested in the high cycle fatigue regime to determine their corresponding fatigue limits. A series of fatigue specimens were tested without polishing and other series after a careful polishing of the cut edges, in order to assess the influence of the cut edges condition. Results indicate a significant influence of the edge roughness, more distinctive for AISI 301LN than for TWIP steel.

  5. Influence of Specimen Preparation and Test Methods on the Flexural Strength Results of Monolithic Zirconia Materials.

    Science.gov (United States)

    Schatz, Christine; Strickstrock, Monika; Roos, Malgorzata; Edelhoff, Daniel; Eichberger, Marlis; Zylla, Isabella-Maria; Stawarczyk, Bogna

    2016-03-09

    The aim of this work was to evaluate the influence of specimen preparation and test method on the flexural strength results of monolithic zirconia. Different monolithic zirconia materials (Ceramill Zolid (Amann Girrbach, Koblach, Austria), Zenostar ZrTranslucent (Wieland Dental, Pforzheim, Germany), and DD Bio zx² (Dental Direkt, Spenge, Germany)) were tested with three different methods: 3-point, 4-point, and biaxial flexural strength. Additionally, different specimen preparation methods were applied: either dry polishing before sintering or wet polishing after sintering. Each subgroup included 40 specimens. The surface roughness was assessed using scanning electron microscopy (SEM) and a profilometer whereas monoclinic phase transformation was investigated with X-ray diffraction. The data were analyzed using a three-way Analysis of Variance (ANOVA) with respect to the three factors: zirconia, specimen preparation, and test method. One-way ANOVA was conducted for the test method and zirconia factors within the combination of two other factors. A 2-parameter Weibull distribution assumption was applied to analyze the reliability under different testing conditions. In general, values measured using the 4-point test method presented the lowest flexural strength values. The flexural strength findings can be grouped in the following order: 4-point strength values than prepared before sintering. The Weibull moduli ranged from 5.1 to 16.5. Specimens polished before sintering showed higher surface roughness values than specimens polished after sintering. In contrast, no strong impact of the polishing procedures on the monoclinic surface layer was observed. No impact of zirconia material on flexural strength was found. The test method and the preparation method significantly influenced the flexural strength values.

  6. Influence of microstructure of high-strength low-alloy steels on their weldability

    International Nuclear Information System (INIS)

    Cwiek, J.; Labanowski, J.

    2003-01-01

    Microstructure of steel before welding has influence on the steel's susceptibility to cold cracking because it influences hardenability and maximum hardness of heat affected zone (HAZ). Two high-strength low-alloy (HSLA) steel grades 18G2AV and 14HNMBCu, in various heat treatment conditions, were subjected to simulated welding thermal cycles. It was revealed that maximum HAZ hardness is influenced by microstructure presented before thermal cycle was applied. The higher HAZ hardness was observed for quenched and tempered condition, comparing to full annealed and overheated conditions. (author)

  7. On the influence of moisture and load variations on the strength behavior of wood

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    2005-01-01

    Abstract: It is demonstrated in this paper that the influence of moisture- and load variations on lifetime and residual strength (re-cycle strength) of wood can be considered by theories previously developed by the author. The common, controlling factor is creep, which can be modified very easily...... by introducing a special moisture dependent relaxation time in the well-known Power-Law creep expression. Because basic failure mechanisms in wood are invariant with respect to loading modes, it is suggested that a number of methods used in design of wood structures can be generalized/simplified to apply...

  8. The Influence of Diatomite on the Strength and Microstructure of Portland Cement

    OpenAIRE

    Liu Jun; Shao Peng; Wang Shihao

    2016-01-01

    To study the influence of the types and mixing amount of diatomite on the Portland cement, we prepared the cement specimen doped with the calcined first-grade, first-grade and second-grade diatomite ,tested the 3d, 7d, 14d compressive strength, and studied and discussed phase, structure and morphology of diatomite in the binary system by the method of XRD, SEM . Experimental results show that with the addition of diatomite, the strength of cement paste increase; the optimal contents of calcin...

  9. Influence of the Reclaim from the Cordis Technology on the Core Sand Strength

    Directory of Open Access Journals (Sweden)

    Dańko J.

    2014-12-01

    Full Text Available The investigation results of the mechanical reclamation of spent moulding sands from the Cordis technology are presented in the paper. The quality assessment of the obtained reclaim and the influence of the reclaim fraction in a matrix on the core sand strength is given. The reclaim quality assessment was performed on the basis of the determination of losses on ignition, Na2O content on reclaim grains and pH values. The reclaim constituted 100%, 75% and 50% of the core sand matrix, for which the bending strength was determined. The matrix reclamation treatment was performed in the experimental rotor reclaimer RD-6. Spent sands were applied in as-delivered condition and after the heating to a temperature of 140 °C. Shaped samples for strength tests were made by shooting and hardening of sands in the warmbox technology.

  10. Influence of surface modified basalt fiber on strength of cinder lightweight aggregate concrete

    Science.gov (United States)

    Xiao, Liguang; Li, Jiheng; Liu, Qingshun

    2017-12-01

    In order to improve the bonding and bridging effect between volcanic slag lightweight aggregate concrete cement and basalt fiber, The basalt fiber was subjected to etching and roughening treatment by NaOH solution, and the surface of the basalt fiber was treated with a mixture of sodium silicate and micro-silica powder. The influence of modified basalt fiber on the strength of volcanic slag lightweight aggregate concrete was systematically studied. The experimental results show that the modified basalt fiber volcanic slag lightweight aggregate concrete has a flexural strength increased by 47%, the compressive strength is improved by 16% and the toughness is increased by 27% compared with that of the non-fiber.

  11. Probabilistic concept to describe the influence of rate of loading on strength of concrete

    International Nuclear Information System (INIS)

    Mihashi, H.; Wittmann, F.H.

    1981-01-01

    Any reliability assessment of concrete structures is dependent on realistic assumptions on strength distribution. By means of experimental test series the most appropriate distribution function cannot be determined. In this contribution a theoretical concept to describe variability of strength of concrete will be presented. This approach is based on the characteristic composite structure. The structure of concrete is composed of aggregates and a binding agent i.e. porous hardened cement paste. Under formal conditions there are already big pores and cracks in the matrix as well as in the interface before a specimen is loaded. All structural defects can be assumed to be statistically distributed all over the specimen. If a load is applied cracks start to grow form the most critical structural defects. For a realistic estimation of the reliability of a secondary containment under impact loading conditions the influence of rate of loading on mean value and variability of strength is of major interest. The presented theory predicts that the mean strength increases with a power law as the rate of loading increases, while the coefficient of variation remains constant. A number of test series have been carried out to verify the theoretical concept. Different types of mortar (model concrete) and concrete have been included in the test program. Within the range of accuracy experimental results agree well with theoretical predictions. It can be concluded that the variability of macroscopic properties of concrete can be linked with the distribution of structural defects. Strength of concrete is best represented by a Weibull-type distribution function. The influence of rate of loading on strength can be experessed by means of a general rate process. (orig.)

  12. Factors Influencing the Outcomes in Extradural Haematoma Patients

    African Journals Online (AJOL)

    neurosurgical emergencies and are one of the most common causes of mortality and disability after traumatic brain injury. This study aimed at evaluating the current management and factors that influence outcome in patients treated for extradural hematoma in an African setting. Methods: A total of 224 consecutive patients ...

  13. Activity limitations and factors influencing functional outcome of ...

    African Journals Online (AJOL)

    EB

    2013-09-03

    Sep 3, 2013 ... life and satisfaction with life1,22. A recent study conducted among community dwelling stroke survivors found functional ability and independence to be the strongest predictor of, and were responsible for the greatest variance on participation22. For determining the factors influencing outcome with the use ...

  14. The influence of various risk factors on the strength of pelvic floor muscle in women

    Directory of Open Access Journals (Sweden)

    Parezanović-Ilić Katarina

    2017-01-01

    Full Text Available Background/Aim. Damage of any element of pelvic floor leads to its functional damages, reflected in the occurrence of urinary incontinence, prolapse of pelvic organs, fecal incontinence and sexual dysfunction. Basic aim of our paper was to investigate the influence of various risk factors on pelvic floor muscle strength in women. Methods. The study included 90 female patients and examined how age, job, body weight and height, number of deliveries, sports activities, incontinence occurrence, previous prolapse-caused gynecological surgeries, other gynecological surgeries and other conservatively treated gynecological diseases influence the value of pelvic floor muscle strength. Pelvic floor muscle strength was measured using vaginal dynamometer. Results. Univariate regression analysis showed that parameters such as age, demanding job, body height, number of deliveries, sports activities, prolapse-caused gynecological surgeries, other gynecological surgeries and other gynecological diseases were in positive correlation with the values of pelvic floor muscle strength. In multivariate regression model, incontinence and gynecological operation of prolapse were singled out as independent risk factors. Conclusion. If risk factors that cause damage to pelvic floor muscle are known, it is possible to prevent the damages and improve the quality of women's life.

  15. Subclinical hypothyroidism has little influences on muscle mass or strength in elderly people.

    Science.gov (United States)

    Moon, Min Kyong; Lee, You Jin; Choi, Sung Hee; Lim, Soo; Yang, Eun Joo; Lim, Jae-Young; Paik, Nam-Jong; Kim, Ki Woong; Park, Kyong Soo; Jang, Hak C; Cho, Bo Youn; Park, Young Joo

    2010-08-01

    Sarcopenia, the age-related decline in muscle mass, affects the muscle strength and muscle quality, and these changes decrease functional capacity. The prevalence of thyroid dysfunction increases with age, and changes in thyroid hormone level lead to neuromuscular deficits. We investigated the effects of subclinical hypothyroidism on the muscle mass, strength or quality in elderly people. One thousand one hundred eighteen subjects aged > or = 65 yr were randomly selected from a local population and classified into a euthyroid (280 men and 358 women), subclinically hypothyroid (61 men and 75 women), or overtly hypothyroid (7 men and 16 women) group. Although women with subclinical hypothyroidism had a higher prevalence of sarcopenia, defined according to the ratio of appendicular skeletal muscle mass to the square of height, muscle mass, strength or quality did not differ in relation to thyroid status in men or in women. Multivariate analysis including age, diabetes, hypertension, acute coronary event, alcohol, smoking, presence of pain, physical activity score, and lipid profile, showed that thyroid-stimulating hormone level was not associated with muscle mass, strength or quality. In conclusion, subclinical hypothyroidism has little influences on muscle mass, strength or quality, and may not be associated with sarcopenia.

  16. Influence of silica fume and fly ash on hydration, microstructure and strength of cement based mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Weng, Kaimao

    1992-10-01

    The influence of fly ash and silica fume on the hydration, microstructure and strength of cement-based mixtures was investigated. A literature review of the hydration processes, compressive strength development, and microstructure of Portland cement is presented, followed by description of materials and specimens preparation and experimental methodology. It was found that silica fume retards cement hydration at low water/concrete ratios. It reduces calcium hydroxide significantly and increases the amount of hydrates at early ages. Fly ash retards hydration more significantly at high water/concrete ratios than at low ratios. The combination of silica fume and fly ash further retards hydration at one day. Silica fume dominates the reaction with calcium hydroxide. Silica fume significantly increases early strength of mortars and concrete, while fly ash reduces early strength. Silica fume can substantially increase strength of fly ash mortar and concrete after 7 days. Silica fume refines pores in the range 100-500 A, while fly ash mortars exhibit gradual pore refinement as hydration proceeds. Silica fume dominates the pore refinement if used with fly ash. 89 refs., 74 figs., 16 tabs.

  17. Papain-based gel for biochemical caries removal: influence on microtensile bond strength to dentin

    Directory of Open Access Journals (Sweden)

    Evandro Piva

    2008-12-01

    Full Text Available This study investigated the influence of a papain-based gel (Papacárie for chemo-mechanical caries removal on bond strength to dentin. Human molars were assigned to the following groups: Group 1: sound teeth were flattened to expose dentin; Group 2: after flattening of surfaces, the papain-based gel was applied on the sound dentin; Group 3: overlying enamel from carious teeth was removed and mechanical excavation of dentin was conducted; Group 4: chemo-mechanical excavation of carious dentin was conducted using the papain-based gel. The Prime&Bond NT or Clearfil SE Bond adhesive systems were used for restorative procedures. A microtensile bond strength test was performed, and the modes of failure were determined under SEM. The data were submitted to two-way ANOVA and Tukey's test (p < 0.05. No significant differences were observed between the sound dentin groups. For both excavation methods, Clearfil presented a significantly higher bond strength than Prime&Bond NT. Also, for Clearfil, the mechanically excavated samples disclosed a significantly higher bond strength than the chemo-mechanically ones. For Prime&Bond NT, no significant differences were detected between the excavation methods. Predominance of mixed failures for the sound substrate and of adhesive failures for the carious dentin one was detected. The bond strength to carious dentin of the self-etching system was negatively affected by chemo-mechanical excavation using the papain-based gel.

  18. The influence of caffeine ingestion on strength and power performance in female team-sport players.

    Science.gov (United States)

    Ali, Ajmol; O'Donnell, Jemma; Foskett, Andrew; Rutherfurd-Markwick, Kay

    2016-01-01

    The aim of this study was to examine the influence of caffeine supplementation on knee flexor and knee extensor strength before, during and after intermittent running exercise in female team-sport players taking oral contraceptive steroids (OCS). Ten healthy females (24 ± 4 years; 59.7 ± 3.5 kg; undertaking 2-6 training sessions per week) taking low-dose monophasic oral contraceptives of the same hormonal composition took part in a randomised, double-blind, placebo-controlled crossover-design trial. Sixty minutes following the ingestion of a capsule containing 6 mg∙kg -1 body mass anhydrous caffeine or artificial sweetener (placebo), participants completed a 90-min intermittent treadmill-running protocol. Isometric strength performance and eccentric and concentric strength and power of the knee flexors and knee extensors (using isokinetic dynamometer), as well as countermovement jump (CMJ), was measured before, during and after the exercise protocol, as well as ~12 h post-exercise. Blood samples were taken before, during and post-exercise to measure glucose, insulin and free fatty acids (FFA). Caffeine supplementation significantly increased eccentric strength of the knee flexors ( P  performance. FFA was elevated with caffeine supplementation over time ( P  caffeine intake. Caffeine supplementation increased eccentric strength and power in female team-sport players taking OCS both during an intermittent running protocol and the following morning.

  19. Influence of superplasticizer on microstructure of a 40 MPa strength concrete

    International Nuclear Information System (INIS)

    Teixeira, Sandra M.F.; Menezes, Raquel Maria R.O.; Figueiredo, Roberto B.; Aguilar, Maria Teresa P.; Franca, Fabricio Carlos; Bezerra, Augusto Cesar da S.

    2016-01-01

    The self compacting concrete has high fluidity and deformability. Studies analyze its performance through compressive strength, mortar content and / or water cement factor, which does not allow the evaluation of superplasticante influence the microstructure of these concretes. In this work, we evaluated the influence of superplasticizer comparing the phases present in a self-compacting concrete 40 MPa and at a same conventional compressive strength, same water / cement and mortar content. Therefore, scanning techniques were employed by electron microscope low vacuum using backscattered electrons and thermal analysis. The observed results show no significant differences in the microstructure of the two composites, ie the superplasticizer does not alter the microstructure of the self-compacting concrete. However, thermal analysis indicates that the present self-compacting concrete greater calcium hydroxide content which may suggest a lower content of such dry cement concrete. (author)

  20. Influence of ionic strength on the viscosities and water loss of bentonite suspensions containing polymers

    Directory of Open Access Journals (Sweden)

    Luciana Viana Amorim

    2007-03-01

    Full Text Available A study was made of the influence of ionic strength (S on the apparent (AV and plastic (PV viscosities and water loss (WL of sodium bentonite suspension with polymers. Na-bentonite was dispersed in water (4.86% w/w of different ionic strengths (S = 0.0, 0.015, 0.030 and 0.045 M followed by the addition of polymer. Three polymer samples were studied, i.e., low viscosity carboxymethyl cellulose (CMC BV, polyanionic cellulose (PAC, and partially hydrolyzed polyacrylamide (HPAM. The results indicated that the presence of salts and increased salinity greatly influence the apparent and plastic viscosities and water loss of bentonite suspensions with polymer.

  1. Influence of Temperature on Workability and Compressive Strength of Ordinary Concrete with High Calcium Fly Ash

    Directory of Open Access Journals (Sweden)

    Gołaszewski Jacek

    2017-06-01

    Full Text Available The rheological properties of fresh ordinary concrete are closely affected by temperature and time. The paper presents the study of consistency of fresh concrete mixtures made with Portland cement and cement with calcareous fly ash. Two types of admixtures were used. It was proven that the temperature has a clear effect on workability and compressive strength concrete. Influence on workability can be reduced by selecting the appropriate superplasticizer and cement.

  2. The influence of water removal on the strength and toughness of cortical bone

    OpenAIRE

    Nyman, Jeffry S.; Roy, Anuradha; Shen, Xinmei; Acuna, Rae L.; Tyler, Jerrod H.; Wang, Xiaodu

    2006-01-01

    Although the effects of dehydration on the mechanical behavior of cortical bone are known, the underlying mechanisms for such effects are not clear. We hypothesize that the interactions of water with the collagen and mineral phases each have a unique influence on mechanical behavior. To study this, strength, toughness, and stiffness were measured with three-point bend specimens made from the mid-diaphysis of human cadaveric femurs and divided into six test groups: control (hydrated), drying i...

  3. Genetic and Environmental Influences on Pulmonary Function and Muscle Strength: The Chinese Twin Study of Aging

    DEFF Research Database (Denmark)

    Tian, Xiaocao; Xu, Chunsheng; Wu, Yili

    2017-01-01

    Genetic and environmental influences on predictors of decline in daily functioning, including forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), handgrip, and five-times-sit-to-stand test (FTSST), have not been addressed in the aging Chinese population. We performed classical twin...... was moderate for FEV1, handgrip, and FTSST (55-60%) but insignificant for FVC. Only FVC showed moderate control, with shared environmental factors accounting for about 50% of the total variance. In contrast, all measures of pulmonary function and muscle strength showed modest influences from the unique...

  4. Incidental emotions influence risk preference and outcome evaluation.

    Science.gov (United States)

    Zhao, Ding; Gu, Ruolei; Tang, Ping; Yang, Qiwei; Luo, Yue-Jia

    2016-10-01

    Incidental emotions, which are irrelevant to the current decision, play a significant role in the decision-making process. In this study, to investigate the influence of incidental emotions on behavioral, psychological, and electrophysiological responses in the process of decision making, participants were required to perform a monetary gambling task. During the selection stage, an emotional picture, which was chosen from the Chinese Affective Picture System and fell into one of three categories: negative, neutral, and positive, was presented between two alternatives (small/large amount of bet). The pictures were provided to induce incidental emotions. ERPs and self-rating emotional experiences to outcome feedback were recorded during the task. Behavioral results showed that positive incidental emotions elicited risk preference, but emotional experiences to outcome feedback were not influenced by incidental emotions. The feedback-related negativity amplitudes were larger in the positive emotion condition than in the negative and neutral emotion conditions for small outcomes (including wins and losses), whereas there was no difference between the three conditions for large outcomes. In addition, the amplitudes of P3 were reduced overall in the negative emotion condition. We suggest that incidental emotions have modulated both the option assessment stage (manifested in behavioral choices) and the outcome evaluation stage (manifested in ERP amplitudes) of decision making unconsciously (indicated by unchanged subjective emotional experiences). The current findings have expanded our understanding of the role of incidental emotion in decision making. © 2016 Society for Psychophysiological Research.

  5. Early return to baseline range of motion and strength after anterior shoulder instability surgery: a Multicenter Orthopaedic Outcomes Network (MOON) shoulder group cohort study.

    Science.gov (United States)

    Buckwalter V, Joseph A; Wolf, Brian R; Glass, Natalie; Bollier, Matt; Kuhn, John E; Hettrich, Carolyn M

    2018-03-23

    Patients often return to higher-level activities and sports at 4 to 8 months after anterior shoulder stabilization procedures. It is unknown what percentage of patients have regained normal function at this time frame and what factors predict residual deficits, range of motion (ROM), and strength after anterior shoulder instability surgery. Ten participating sites throughout the United States enrolled patients in a prospective cohort study including primary, revision, arthroscopic, and open anterior stabilization procedures. Baseline demographic data and patient outcomes questionnaires were collected with initial physical examination, treatment, surgical findings, and surgical repair details. At the 6-month follow-up visit, ROM and strength measurements were collected and compared with preoperative measurements. There were 348 patients identified who underwent surgical treatment for anterior shoulder instability. Of these, 259 patients (74.0%) returned to baseline, and 89 (26.0%) did not return to baseline shoulder ROM (≥20° loss of ROM) or strength. A higher Beighton score (P = .01) and number of dislocations (P baseline ROM and strength at early follow-up. No surgical variables were found to influence return to baseline function, including open vs. arthroscopic surgery, primary vs. revision surgery, and number of suture anchors. By 4 to 8 months postoperatively, 76% of patients return to baseline ROM, 98% return to baseline strength, and 74% return to both baseline ROM and strength. An increased number of dislocations and generalized joint laxity were associated with failure to return to baseline ROM and strength at early follow-up after anterior shoulder instability surgery. Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  6. Influence of manufacturing parameters on the strength of PLA parts using Layered Manufacturing technique: A statistical approach

    Science.gov (United States)

    Jaya Christiyan, K. G.; Chandrasekhar, U.; Mathivanan, N. Rajesh; Venkateswarlu, K.

    2018-02-01

    A 3D printing was successfully used to fabricate samples of Polylactic Acid (PLA). Processing parameters such as Lay-up speed, Lay-up thickness, and printing nozzle were varied. All samples were tested for flexural strength using three point load test. A statistical mathematical model was developed to correlate the processing parameters with flexural strength. The result clearly demonstrated that the lay-up thickness and nozzle diameter influenced flexural strength significantly, whereas lay-up speed hardly influenced the flexural strength.

  7. Influence of variables on the consolidation and unconfined compressive strength of crushed salt: Technical report

    International Nuclear Information System (INIS)

    Pfeifle, T.W.; Senseny, P.E.; Mellegard, K.D.

    1987-01-01

    Eight hydrostatic compression creep tests were performed on crushed salt specimens fabricated from Avery Island dome salt. Following the creep test, each specimen was tested in unconfined compression. The experiments were performed to assess the influence of the following four variables on the consolidation and unconfined strength of crushed salt: grain size distribution, temperature, time, and moisture content. The experiment design comprised a half-fraction factorial matrix at two levels. The levels of each variable investigated were grain size distribution, uniform-graded and well-graded (coefficient of uniformity of 1 and 8); temperature 25 0 C and 100 0 C; time, 3.5 x 10 3 s and 950 x 10 3 s (approximately 60 minutes and 11 days, respectively); and moisture content, dry and wet (85% relative humidity for 24 hours). The hydrostatic creep stress was 10 MPa. The unconfined compression tests were performed at an axial strain rate of 1 x 10 -5 s -1 . Results show that the variables time and moisture content have the greatest influence on creep consolidation, while grain size distribution and, to a somewhat lesser degree, temperature have the greatest influence on total consolidation. Time and moisture content and the confounded two-factor interactions between either grain size distribution and time or temperature and moisture content have the greatest influence on unconfined strength. 7 refs., 7 figs., 11 tabs

  8. The influence of double nested layer waviness on compression strength of carbon fiber composite materials

    International Nuclear Information System (INIS)

    Khan, Z.M.

    1997-01-01

    As advanced composite materials having superior physical and mechanical properties are being developed, optimization of their production processes in eagerly being sought. One of the most common defect in production of structural composites is layer waviness. Layer waviness is more pronounced in thick section flat and cylindrical laminates that are extensively used in missile casings, submersibles and space platforms. Layer waviness undulates the entire layers of a multidirectional laminate in through-the-thickness direction leading to gross deterioration of its compression strength. This research investigates the influence of multiple layer waviness in a double nest formation on the compression strength of a composite laminate. Different wave fractions of wave 0 degree centigrade layer fabricated in IM/85510-7 carbon - epoxy composite laminate on a steel mold using single step fabrication procedure. The laminate was cured on a heated press according to specific curing cycle. Static compression testing was performed using NASA short block compression fixture on an MTS servo Hydraulic machine. The purpose of these tests was to determine the effects of multiple layer wave regions on the compression strength of composite laminate. The experimental and analytical results revealed that up to about 35% fraction of wave 0 degree layer exceeded 35%. This analysis indicated that the percentage of 0 degree wavy layer may be used to estimate the reduction in compression strength of a composite laminate under restricted conditions. (author)

  9. Influence of Post Weld Heat Treatment on Strength of Three Aluminum Alloys Used in Light Poles

    Directory of Open Access Journals (Sweden)

    Craig C. Menzemer

    2016-03-01

    Full Text Available The conjoint influence of welding and artificial aging on mechanical properties were investigated for extrusions of aluminum alloy 6063, 6061, and 6005A. Uniaxial tensile tests were conducted on the aluminum alloys 6063-T4, 6061-T4, and 6005A-T1 in both the as-received (AR and as-welded (AW conditions. Tensile tests were also conducted on the AR and AW alloys, subsequent to artificial aging. The welding process used was gas metal arc (GMAW with spray transfer using 120–220 A of current at 22 V. The artificial aging used was a precipitation heat treatment for 6 h at 182 °C (360 °F. Tensile tests revealed the welded aluminum alloys to have lower strength, both for yield and ultimate tensile strength, when compared to the as-received un-welded counterpart. The beneficial influence of post weld heat treatment (PWHT on strength and ductility is presented and discussed in terms of current design provisions for welded aluminum light pole structures.

  10. Influence of intrapulpal pressure simulation on the bond strength of adhesive systems to dentin

    Directory of Open Access Journals (Sweden)

    Marcio Vivan Cardoso

    2008-06-01

    Full Text Available The purpose of this study was to evaluate the influence of intrapulpal pressure simulation on the bonding effectiveness of etch & rinse and self-etch adhesives to dentin. Eighty sound human molars were distributed into eight groups, according to the permeability level of each sample, measured by an apparatus to assess hydraulic conductance (Lp. Thus, a similar mean permeability was achieved in each group. Three etch & rinse adhesives (Prime & Bond NT - PB, Single Bond -SB, and Excite - EX and one self-etch system (Clearfil SE Bond - SE were employed, varying the presence or absence of an intrapulpal pressure (IPP simulation of 15 cmH2O. After adhesive and restorative procedures were carried out, the samples were stored in distilled water for 24 hours at 37°C, and taken for tensile bond strength (TBS testing. Fracture analysis was performed using a light microscope at 40 X magnification. The data, obtained in MPa, were then submitted to the Kruskal-Wallis test ( a = 0.05. The results revealed that the TBS of SB and EX was significantly reduced under IPP simulation, differing from the TBS of PB and SE. Moreover, SE obtained the highest bond strength values in the presence of IPP. It could be concluded that IPP simulation can influence the bond strength of certain adhesive systems to dentin and should be considered when in vitro studies are conducted.

  11. Factors influencing the thermally-induced strength degradation of B/Al composites

    Science.gov (United States)

    Dicarlo, J. A.

    1983-01-01

    Literature data related to the thermally-induced strength degradation of B/Al composites were examined in the light of fracture theories based on reaction-controlled fiber weakening. Under the assumption of a parabolic time-dependent growth for the interfacial reaction product, a Griffith-type fracture model was found to yield simple equations whose predictions were in good agreement with data for boron fiber average strength and for B/Al axial fracture strain. The only variables in these equations were the time and temperature of the thermal exposure and an empirical factor related to fiber surface smoothness prior to composite consolidation. Such variables as fiber diameter and aluminum alloy composition were found to have little influence. The basic and practical implications of the fracture model equations are discussed. Previously announced in STAR as N82-24297

  12. Influence of acute static stretching on the behavior of maximum muscle strength

    Directory of Open Access Journals (Sweden)

    Carmen Lúcia Borges Bastos

    2014-06-01

    Full Text Available The aim of this study was to compare the influence of acute static stretching on maximal muscle strength (1RM. The non-probabilistic sample consisted of 30 subjects split into two groups: static stretching (SS= 15 and without stretching group (WS= 15. Muscle strength evaluation (1RM was conducted with a Dynamometer model 32527pp400 Pound push / pull devices coupled in knee extension (KE and bench press (BP. The Wilcoxon test for intragroup comparisons and the Kruskal-Wallis test for comparisons between groups (p< 0.05 were selected. There were no significant differences (p> 0.05 between the SS and WS in exercise KE and BP. Therefore, it can be concluded that there was no reduction in the performance of 1RM performing the exercises KE and BP when preceded by static stretching.

  13. Factors influencing the thermally-induced strength degradation of B/Al composites

    International Nuclear Information System (INIS)

    Dicarlo, J.A.

    1983-01-01

    Literature data related to the thermally-induced strength degradation of B/Al composites were examined in the light of fracture theories based on reaction-controlled fiber weakening. Under the assumption of a parabolic time-dependent growth for the interfacial reaction product, a Griffith-type fracture model was found to yield simple equations whose predictions were in good agreement with data for boron fiber average strength and for B/Al axial fracture strain. The only variables in these equations were the time and temperature of the thermal exposure and an empirical factor related to fiber surface smoothness prior to composite consolidation. Such variables as fiber diameter and aluminum alloy composition were found to have little influence. The basic and practical implications of the fracture model equations are discussed

  14. Influence of Fly Ash on the Compressive Strength of Foamed Concrete at Elevated Temperature

    Directory of Open Access Journals (Sweden)

    Ahmad H.

    2014-01-01

    Full Text Available Foamed concrete is a lightweight concrete that is widely used in the construction industry recently. This study was carried out to investigate the influence of fly ash as a cement replacement material to the residual compressive strength of foamed concrete subjected to elevated temperature. For this study, the foamed concrete density was fixed at 1300 kg/m3 and the sand-cement ratio and water-cement was set at 1:2 and 0.45, respectively. The samples were prepared and tested at the age of 28 days. Based on the results, it has been found that with 25% inclusion of fly ash, the percentage of compressive strength loss was decreased by 3 – 50%.

  15. Change in the level of strength and endurance development of 5-6 grades pupils under cheerleading exercises influence

    Directory of Open Access Journals (Sweden)

    Tetyana Bala

    2015-06-01

    Full Text Available Purpose: determine the degree of change in the level of strength and endurance development of 5-6 grades pupils under cheerleading exercises influence. Material and Methods: theoretical analysis and generalization of scientific and methodical literature, pedagogical testing, pedagogical experiment and mathematical statistics methods. Results: parameters of strength and endurance development level are presented with their degree of change under cheerleading exercises influence for 5-6 grades pupils of secondary school. Conclusions: cheerleading exercises usage has positive influence on demonstrated strength and endurance degree of secondary school children by all investigated parameters.

  16. Influence of the Category Discharge Processing on Strength Properties of Piezocomposites

    International Nuclear Information System (INIS)

    Ramazanov, M. A.

    2006-01-01

    Piezoelectric, dielectric and physicomechanical properties of polymeric piezocomposites on piezoceramics basis are one of the major operational devices of applications. During their application in various devices for a long time can be exposed to various influences for a long time. Piezoelectric, dielectric and strength properties of polymeric piezocomposites strongly depend from the interphase phenomena, and also on charges saved up on border of the unit between components of a composition. Therefore creation the preliminary centers localization for charges in a composition is an actual problem for development effective polymeric piezocomposites. In the given work results of a research preliminary discharge processing's of powders of polymer on strength properties and dielectric characteristics of polymeric compositions on a basis polyvinilidenftorid (PVDF), high density polyethylene and piezoceramic from tetragonal structure are poisoned. Piezoceramic had structure plumbum-zirconate-titanate (PZT). Powders of polymer have been subjected to discharge processing in a quartz glass tube with a diameter 15 mm which walls with 1 mm. It is earthed, from one end and to other end it is connected with high-voltage electrode. Compositions in a volumetric ratio of 90+10 % have been obtained at temperature 435Κ under pressure 15ΜΠa. After creation reception of samples they were exposed electrothermopolarization. It is experimentally established, that after discharge processing powders of polymer depending on of processing duration electric and mechanical durability, and also an accrued charge on border of the unit of phases up to the certain value increases, and then decreases. Also it is shown, hat influence of category processing on strength and dielectric characteristics of a composition on the basis of polymer PVDF is more than , has on polyethylene basis. Changes piezoelectric, dielectric it is supposed, that, and strength properties to an extreme piezocomposite

  17. Influence of the supporting die structures on the fracture strength of all-ceramic materials.

    Science.gov (United States)

    Yucel, Munir Tolga; Yondem, Isa; Aykent, Filiz; Eraslan, Oğuz

    2012-08-01

    This study investigated the influence of the elastic modulus of supporting dies on the fracture strengths of all-ceramic materials used in dental crowns. Four different types of supporting die materials (dentin, epoxy resin, brass, and stainless steel) (24 per group) were prepared using a milling machine to simulate a mandibular molar all-ceramic core preparation. A total number of 96 zirconia cores were fabricated using a CAD/CAM system. The specimens were divided into two groups. In the first group, cores were cemented to substructures using a dual-cure resin cement. In the second group, cores were not cemented to the supporting dies. The specimens were loaded using a universal testing machine at a crosshead speed of 0.5 mm/min until fracture occurred. Data were statistically analyzed using two-way analysis of variance and Tukey HSD tests (α = 0.05). The geometric models of cores and supporting die materials were developed using finite element method to obtain the stress distribution of the forces. Cemented groups showed statistically higher fracture strength values than non-cemented groups. While ceramic cores on stainless steel dies showed the highest fracture strength values, ceramic cores on dentin dies showed the lowest fracture strength values among the groups. The elastic modulus of the supporting die structure is a significant factor in determining the fracture resistance of all-ceramic crowns. Using supporting die structures that have a low elastic modulus may be suitable for fracture strength tests, in order to accurately reflect clinical conditions.

  18. Influence of bleaching and desensitizing gel on bond strength of orthodontic brackets

    Directory of Open Access Journals (Sweden)

    Fernanda Alves Rodrigues Britto

    2015-04-01

    Full Text Available OBJECTIVE: The objective of this study was to assess, in vitro, the influence of bleaching gel and the use of desensitizing agent over bond strength of ceramic brackets bonded to bovine enamel. METHODS: One hundred bovine incisors were selected and randomly divided into five groups (n = 20: Group 1, control group (without bleaching; Group 2, bleached with 35% hydrogen peroxide; Group 3, bleached with 35% hydrogen peroxide (three applications, 15 minutes each and desensitizing agent applied for 10 minutes; Group 4, bleached with 35% hydrogen peroxide for 40 minutes; Group 5, bleached with 35% hydrogen peroxide for 40 minutes with desensitizing agent applied for 10 minutes. Brackets were bonded 7 days after bleaching and submitted to shear bond strength test after 24 hours at a compression rate of 1 mm/minute. After fracture, the adhesive remnant index (ARI was assessed under stereoscopic at 40 x magnification. Shear strength data (MPa were submitted to one-way ANOVA and Tukey's test with significance level set at 5%. RESULTS: Group 5 (29.33 MPa showed significantly higher bond strength than Group 1 (19.19 MPa, Group 2 (20.59 MPa and Group 4 (23.25 MPa, but with no difference in comparison to Group 3. There was no significant difference among the other groups. The adhesive remnant index showed predominance of score 3, that is, all resin remained adhered to enamel for all groups. CONCLUSION: Bleaching with 35% hydrogen peroxide with calcium associated with desensitizing agent application produced higher bond strength values of brackets bonded to bovine enamel.

  19. The dance’s influence on muscle strength of lower limbs on the elderly

    Directory of Open Access Journals (Sweden)

    Joseane Rodrigues da Silva

    2011-09-01

    Full Text Available The aim of this study was to evaluate the influence of dance in the lower limb muscle strength on the elderly. This research has a qualitative-quantitative aproach. The sample was composed by ten elderly of both sexes, who practiced ballroom dancing classes during twelve weeks. The evaluation was performed before and after the classes and it was composed by a questionnaire with personal data and medical history, “test stand and sit in 30 seconds” and a semi-structured interview with a guiding question regarding the perception of muscular strength of the elderly. The quantitative analysis was performed using the Student’s t-test with a significance level of p<0,05%. The qualitative analysis was made according directions proposed by Minayo (1994. The evaluation of muscle strength measured by the test of sitting and standing up, showed that four participants had a decreased and six had an increase in the number of movements executed, but not existed a significant statistical difference between the values before and after intervention (p=0,1934. However, the speech of the participants showed an improvement on the perception in relation muscle strength, mobility, joviality and self-esteem. It suggests that the effect of the dance, performed in the frequency used in this study, has an effect on the well-being and psychosocial sphere of the elderly. Playful activities in physical therapy performed by groups, bringing benefits, however, it should not be an isolated activity, it should be associated with a specific training to improve muscle strength related to the needs of each elderly.

  20. Heat treatment of a direct composite resin: influence on flexural strength

    Directory of Open Access Journals (Sweden)

    Caroline Lumi Miyazaki

    2009-09-01

    Full Text Available The purpose of this study was to evaluate the flexural strength of a direct composite, for indirect application, that received heat treatment, with or without investment. One indirect composite was used for comparison. For determination of the heat treatment temperature, thermogravimetric analysis (TGA and differential scanning calorimetry (DSC were performed, considering the initial weight loss temperature and glass transition temperature (Tg. Then, after photoactivation (600 mW/cm² - 40 s, the specimens (10 x 2 x 2 mm were heat-treated following these conditions: 170ºC for 5, 10 or 15 min, embedded or not embedded in investment. Flexural strength was assessed as a means to evaluate the influence of different heat treatment periods and investment embedding on mechanical properties. The data were analyzed by ANOVA and Tukey's test (α = 0.05. TGA showed an initial weight loss temperature of 180ºC and DSC showed a Tg value of 157°C. Heat treatment was conducted in an oven (Flli Manfredi, Italy, after 37°C storage for 48 h. Flexural strength was evaluated after 120 h at 37°C storage. The results showed that different periods and investment embedding presented similar statistical values. Nevertheless, the direct composite resin with treatments presented higher values (178.7 MPa compared to the indirect composite resin (146.0 MPa and the same direct composite submitted to photoactivation only (151.7 MPa. Within the limitations of this study, it could be concluded that the heat treatment increased the flexural strength of the direct composite studied, leading to higher mechanical strength compared to the indirect composite.

  1. Influence of Cyclic Straining on Fatigue, Deformation, and Fracture Behavior of High-Strength Alloy Steel

    Science.gov (United States)

    Manigandan, K.; Srivatsan, T. S.; Vasudevan, V. K.; Tammana, D.; Poorganji, B.

    2016-01-01

    In this paper, the results of a study on microstructural influences on mechanical behavior of the high-strength alloy steel Tenax™ 310 are presented and discussed. Under the influence of fully reversed strain cycling, the stress response of this alloy steel revealed softening from the onset of deformation. Cyclic strain resistance exhibited a linear trend for the variation of both elastic strain amplitude with reversals-to-failure, and plastic strain amplitude with reversals-to-failure. Fracture morphology was essentially the same at the macroscopic level over the entire range of cyclic strain amplitudes examined. However, at the fine microscopic level, this high-strength alloy steel revealed fracture to be mixed-mode with features reminiscent of "locally" ductile and brittle mechanisms. The macroscopic mechanisms governing stress response at the fine microscopic level, resultant fatigue life, and final fracture behavior are presented and discussed in light of the mutually interactive influences of intrinsic microstructural effects, deformation characteristics of the microstructural constituents during fully reversed strain cycling, cyclic strain amplitude, and resultant response stress.

  2. The influence of salivary contamination on shear bond strength of dentin adhesive systems.

    Science.gov (United States)

    Park, Jeong-won; Lee, Kyung Chae

    2004-01-01

    This study evaluated the influence of salivary contamination during dentin bonding procedures on shear bond strength and investigated the effect of contaminant-removing treatments on the recovery of bond strength for two dentin bonding agents. One hundred and ten human molars were embedded in cylindrical molds with self-curing acrylic resin. The occlusal dentin surface was exposed by wet grinding with #800 silicon carbide abrasive paper. The teeth were divided into five groups for One-step (OS) (BISCO, Inc) and six groups for Clearfil SE Bond (SE) (Kuraray Co, Ltd, Osaka, Japan). For One-step, the grinding surface was treated with 32% phosphoric acid; BAC (BISCO Inc) and divided into five groups: OS control group (uncontaminated), OS I (salivary contamination, blot dried), OS II (salivary contamination, completely dried), OS III (salivary contamination, wash and blot dried) and OS IV (salivary contamination, re-etching for 10 seconds, wash and blot dried). For SE bond, the following surface treatments were done: SE control group (primer applied to the fresh dentin surface), SE I (after salivary contamination, primer applied), SE II (primer, salivary contamination, dried), SE III (primer, salivary contamination, wash and dried), SE IV (after procedure of SE II, re-application of primer) and SE V (after procedure of SE III, re-application of primer). Each bonding agent was applied and light cured for 10 seconds. Clearfil AP-X (Kuraray Co, Ltd) composite was packed into the Ultradent mount jig mold and light cured for 40 seconds. The bonded specimens were stored for 24 hours in a 37 degrees C waterbath. The shear bond strengths were measured using an Instron testing machine (Model 4202, Instron Corp). The data for each group were subjected to one-way ANOVA followed by the Newman-Keuls test to make comparisons among the groups. The results were as follows: In the One-step groups, the OS II group showed statistically significant lower shear bond strength than the OS

  3. EVALUATING THE INFLUENCE OF MASSAGE ON LEG STRENGTH, SWELLING, AND PAIN FOLLOWING A HALF-MARATHON

    Directory of Open Access Journals (Sweden)

    Peter M. Tiidus

    2004-11-01

    Full Text Available Massage therapy is commonly used following endurance running races with the expectation that it will enhance post-run recovery of muscle function and reduce soreness. A limited number of studies have reported little or no influence of massage therapy on post-exercise muscle recovery. However, no studies have been conducted in a field setting to assess the potential for massage to influence muscle recovery following an actual endurance running race. To evaluate the potential for repeated massage therapy interventions to influence recovery of quadriceps and hamstring muscle soreness, recovery of quadriceps and hamstring muscle strength and reduction of upper leg muscle swelling over a two week recovery period following an actual road running race. Twelve adult recreational runners (8 male, 4 female completed a half marathon (21.1 km road race. On days 1,4, 8, and 11 post-race, subjects received 30 minutes of standardized massage therapy performed by a registered massage therapist on a randomly assigned massage treatment leg, while the other (control leg received no massage treatment. Two days prior to the race (baseline and preceding the treatments on post-race days 1, 4, 8, and 11 the following measures were conducted on each of the massage and control legs: strength of quadriceps and hamstring muscles, leg swelling, and soreness perception. At day 1, post-race quadriceps peak torque was significantly reduced (p 0.05. All measures had returned to baseline at day 11. Massage did not affect the recovery of muscles in terms of physiological measures of strength, swelling, or soreness. However, questionnaires revealed that 7 of the 12 participants perceived that the massaged leg felt better upon recovery.

  4. Influence of Random Inclusion of Coconut Fibres on the Short term Strength of Highly Compressible Clay

    Science.gov (United States)

    Ramani Sujatha, Evangelin; SaiSree, S.; Prabalini, C.; Aysha Farsana, Z.

    2017-07-01

    The choice of natural fibres for soil stabilization provides an economic, safe and eco-friendly alternative to improve the properties of soil. They are an important step forward toward sustainable development. An attempt was made to study the influence of the random addition of untreated coconut fibres on the short term strength of soil, its stress-strain behavior, compaction characteristics and index properties. The soil selected for the study is a highly compressible clay sample with a liquid limit of 52.5 % and plasticity index of 38 %. The soil has no organic content. The study reveals that the compaction curves tend to shift to the right side, indicating more plastic behavior with the addition of fibres. The addition of fibres also reorient the soil structure to a more dispersed fashion. A significant increase in the unconfined compressive strength is also observed. An increase of nearly 51 % in the unconfined compressive strength is observed at 0.75 % coir inclusion. The stress-strain behavior of the soil shows a shift toward more plastic behavior. The mode of failure of the soil specimen is by cracking and with fibre inclusion, length of the failure cracks is restrained as the fibre tends to hold the cracks together, resulting in shorter cracks, with significant bulging of the specimen at failure.

  5. Influence of aggregate characteristics on the compressive strength of normal weight concrete

    International Nuclear Information System (INIS)

    Qureshi, M.A.; Aslam, M.

    2015-01-01

    Experimental investigations on the properties of concrete have been performed around the globe and their correlation is interpreted in relevant design codes. The structural behavior of cement concrete significantly relies on the material resources, properties of the aggregates constituting the concrete and the local construction practice. These factors vary from place to place. Therefore, the compressive strength of concrete prepared from the aggregates available in one locality may not be directly applicable to the other areas. The purpose of this study is to evaluate the Influence of locally available coarse aggregates on the compressive strength of normal weight concrete (NWC) prepared under local environmental conditions of district Khairpur Mir's, Sindh, Pakistan. The coarse aggregates were collected from five different quarries in the vicinity of Khairpur Mir's, Pakistan. In total; 180 cubes were tested. 10 different batches were formed in order to arrange individual characterization of concrete. Each batch was contained of 18 cubes and each quarry contains 2 batches making a total of 36 cube with four different ratios for each quarry. Dry density and compressive strength of concrete was calculated and a comparison is provided as a guideline for the future construction work in the local community. (author)

  6. Bond strength to dentin with artificial carious lesions: influence of caries detecting dye.

    Science.gov (United States)

    Palma, R G; Turbino, M L; Matson, E; Powers, J M

    1998-06-01

    To evaluate the influence of dyes for caries detection on tensile bond strength of adhesive materials to artificial carious dentin. Buccal and lingual enamel of human molars were removed leaving intact dentin surfaces. The entire surface of each specimen was covered with nail varnish, keeping a window area of 4 x 4 mm. Artificial carious lesions were induced with acidified gel. Three dyes (0.5% basic fuchsin; Caries Finder and Cari-D-Tect) were used according to manufacturers' recommendations. Specimens were etched with 35% phosphoric acid for 20 s, washed and dried, leaving a wet dentin surface. The adhesive system (Prime & Bond 2.0) was applied in two layers and light-cured. Restorative materials (TPH Spectrum, Dyract, Advance) were bonded using a 3-mm diameter inverted-cone mold. Control groups were made without dye. Eight samples were tested for each group. After 24 hrs of storage in distilled water, the samples were debonded using a testing machine at 0.5 mm/min crosshead speed. ANOVA and Tukey-Kramer test showed that TPH Spectrum (0.73 MPa) and Dyract (0.74 MPa) had similar bond strengths, and both were higher than Advance (0.0 MPa), which was statistically different (P strength for any tested materials.

  7. Influence of Casting Section Thickness on Fatigue Strength of Austempered Ductile Iron

    Science.gov (United States)

    Olawale, J. O.; Ibitoye, S. A.

    2017-10-01

    The influence of casting section thickness on fatigue strength of austempered ductile iron was investigated in this study. ASTM A536 65-45-12 grade of ductile iron was produced, machined into round samples of 10, 15, 20 and 25 mm diameter, austenitized at a temperature of 820 °C, quenched into an austempering temperature (TA) of 300 and 375 °C and allowed to be isothermally transformed at these temperatures for a fixed period of 2 h. From the samples, fatigue test specimens were machined to conform to ASTM E-466. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) methods were used to characterize microstructural morphology and phase distribution of heat-treated samples. The fatigue strength decreases as the section thickness increases. The SEM image and XRD patterns show a matrix of acicular ferrite and carbon-stabilized austenite with ferrite coarsening and volume fraction of austenite reducing as the section thickness increases. The study concluded that the higher the value of carbon-stabilized austenite the higher the fatigue strength while it decreases as the ausferrite structure becomes coarse.

  8. Influence of enamel conditioning on the shear bond strength of different adhesives.

    Science.gov (United States)

    Brauchli, Lorenz; Muscillo, Teodoro; Steineck, Markus; Wichelhaus, Andrea

    2010-11-01

    Phosphoric acid etching is the gold standard for enamel conditioning. However, it is possible that air abrasion or a combination of air abrasion and etching might result in enhanced adhesion. The aim of this study was to investigate the effect of different enamel conditioning methods on the bond strength of six adhesives. Three different enamel conditioning procedures (phosphoric acid etching, air abrasion, air abrasion + phosphoric acid etching) were evaluated for their influence on the shear bond strength of six different adhesives (Transbond™ XT, Cool-Bond™, Fuji Ortho LC, Ultra Band-Lok, Tetric(®) Flow, Light-Bond™). Each group consisted of 15 specimens. Shear forces were measured with a universal testing machine. The scores of the Adhesive Remnant Index (ARI) were also analyzed. There were no significant differences between phosphoric acid etching and air abrasion + phosphoric acid etching. Air abrasion as a single conditioning technique led to significantly lower shear forces. The ARI scores did not correlate with the shear strengths measured. There were greater variations in shear forces for the different adhesives than for the conditioning techniques. The highest shear forces were found for the conventional composites Transbond™ XT and Cool- Bond™ in combination with conventional etching. Air abrasion alone and in combination with phosphoric acid etching showed no advantages compared with phosphoric acid etching alone and, therefore, cannot be recommended.

  9. Influence of defects on axial fatigue strength of maraging steel specimens produced by additive manufacturing

    Directory of Open Access Journals (Sweden)

    Rigon Daniele

    2018-01-01

    Full Text Available Nowadays many materials such as steels, aluminium and titanium alloys can be realised by powder bed solutions melting subsequently powder layers by means of a laser or electron beam (Laser Beam Melting – LBM and Electron Beam Melting – EBM. The microstructure realised by layer-by-layer solidification having high cooling rate cannot be considered isotropic. Therefore, the mechanical properties could be influenced by the building direction. Regarding maraging steel, the study of the influence of the building direction and the heat treatment on the static and axial fatigue strength has been investigated in a previous contribution. A large scatter of the fatigue test results was found because of the presence of detrimental surface and subsurface defects. The aim of this contribution is to present additional axial fatigue test results of maraging steel characterized by different build orientation and providing an analysis of the defects observed at the crack initiation area of the fracture surface.

  10. Influence of non-metallic inclusions on fatigue strength of high manganese steel

    International Nuclear Information System (INIS)

    Maekawa, I.; Shibata, H.; Lee, J.H.; Nishida, Shin-ichi

    1991-01-01

    Six series of high manganese austenitic steel, which contain different inclusion quantity, were prepared. Fatigue experiments, tensile tests and Charpy tests were carried out. Influence of non-metallic inclusion and of temperature on the stress intensity threshold, fatigue crack propagation behavior, elastic-plastic fracture toughness and Charpy value were studied at room temperature and low temperature. In general, strength of this high manganese steel was reduced with increase of inclusion content. Influences of the direction of elongated inclusion with regard to the rolling direction on their strengths were also discussed based on SEM observation and numerical analysis for the stress concentration at a crack tip when an inclusion was near by the tip. According to these results, an inclusion acted as an obstacle to crack propagation for LT specimen. The roughness of fracture surface of ST specimen was larger than that of SL specimen, and the crack growth rate of the former was less than that of the latter. Fatigue life was increased with decrease of temperature, and mechanical parameters such as ΔK th and J 1c were decreased with increase of temperature. The Charpy value decreased clearly with decrease of temperature

  11. Essential Factors Influencing the Bonding Strength of Cold-Sprayed Aluminum Coatings on Ceramic Substrates

    Science.gov (United States)

    Drehmann, R.; Grund, T.; Lampke, T.; Wielage, B.; Wüstefeld, C.; Motylenko, M.; Rafaja, D.

    2018-02-01

    The present work summarizes the most important results of a research project dealing with the comprehensive investigation of the bonding mechanisms between cold-sprayed Al coatings and various poly- and monocrystalline ceramic substrates (Al2O3, AlN, Si3N4, SiC, MgF2). Due to their exceptional combination of properties, metallized ceramics are gaining more and more importance for a wide variety of applications, especially in electronic engineering. Cold spray provides a quick, flexible, and cost-effective one-step process to apply metallic coatings on ceramic surfaces. However, since most of the existing cold-spray-related publications focus on metallic substrates, only very little is known about the bonding mechanisms acting between cold-sprayed metals and ceramic substrates. In this paper, the essential factors influencing the bonding strength in such composites are identified. Besides mechanical tensile strength testing, a thorough analysis of the coatings and especially the metal/ceramic interfaces was conducted by means of HRTEM, FFT, STEM, EDX, EELS, GAXRD, and EBSD. The influence of substrate material, substrate temperature, and particle size is evaluated. The results suggest that, apart from mechanical interlocking, the adhesion of cold-sprayed metallic coatings on ceramics is based on a complex interplay of different mechanisms such as quasiadiabatic shearing, static recrystallization, and heteroepitaxial growth.

  12. High risk pregnancy in the workplace. Influencing positive outcomes.

    Science.gov (United States)

    Cannon, R B; Schmidt, J V; Cambardella, B; Browne, S E

    2000-09-01

    Childbearing employees are well served by the occupational health nurse who promotes optimal preconceptual and pregnancy health practices, uses community resources, and maintains current knowledge about high risk pregnancy prevention and care. These broad goals of care can lead to decreased absenteeism, healthier and happier employees, and more positive outcomes of pregnancy. For employees with high risk pregnancies, the role of the occupational health nurse includes, but is not limited to, facilitating awareness with the employer, making suggestions for adjusting working conditions, making frequent assessments of the employee's needs, and communicating with prenatal health care providers. Occupational health nurses should never underestimate their role and potential influence on the mother, and on her significant other, for a positive outcome of her pregnancy.

  13. Influence of alkali-silica reaction and crack orientation on the uniaxial compressive strength of concrete cores from slab bridges

    DEFF Research Database (Denmark)

    Antonio Barbosa, Ricardo; Gustenhoff Hansen, Søren; Hansen, Kurt Kielsgaard

    2018-01-01

    ASR-damaged flat slab bridges in service. Furthermore, the influence of the ASR-induced crack orientation on the compressive strength and the Young’s modulus is investigated. Uniaxial compression tests, visual observations, and thin section examinations were performed on more than 100 cores drilled...... from the three severely ASR-damaged flat slab bridges. It was found that the orientation of ASR-induced cracks has a significant influence on the uniaxial compressive strength and the stress-strain relationship of the tested cores. The compressive strength in a direction parallel to ASR cracks can...

  14. The influence of using accelerator addition on High strength self-compacting concrete (HSSCC) in case of enhancement early compressive strength and filling ability parameters

    Science.gov (United States)

    Wibowo; Fadillah, Y.

    2018-03-01

    Efficiency in a construction works is a very important thing. Concrete with ease of workmanship and rapid achievement of service strength will to determine the level of efficiency. In this research, we studied the optimization of accelerator usage in achieving performance on compressive strength of concrete in function of time. The addition of variation of 0.3% - 2.3% to the weight of cement gives a positive impact of the rapid achievement of hardened concrete, however the speed of increasing of concrete strength achievement in term of time influence present increasing value of filling ability parameter of self-compacting concrete. The right composition of accelerator aligned with range of the values standard of filling ability parameters of HSSCC will be an advantage guidance for producers in the ready-mix concrete industry.

  15. Malnutrition is prevalent in patients with cardiorenal syndrome and negatively influences clinical outcome.

    Science.gov (United States)

    Gigante, A; Rosato, E; Barbano, B; Di Mario, F; Di Lazzaro-Giraldi, G; Gasperini, M L; Pofi, R; Laviano, A

    2018-01-01

    Cardiorenal syndrome (CRS) describes the concurrent failure of cardiac and renal function, each influencing the other. Malnutrition and cachexia frequently develop in patients with heart failure or kidney failure. However, no information is currently available on the prevalence of malnutrition in CRS patients. We studied CRS patients admitted to an internal medicine ward during a 5-month period and evaluated their clinical characteristics and nutritional status. Malnutrition risk was assessed by using the validated screening tool NRS-2002 whilst body composition was assessed by bioimpedance analysis and muscle function was measured by handgrip (HG) strength. Cardiac mass was also recorded. Length of stay, hospital readmission and 6-month mortality were registered. During the study period, 22 CRS patients were studied. Twenty patients were diagnosed with either CRS type 1 or CRS type 5. In CRS patients, fat-free mass showed a trend toward representing a protective factor for 6-month mortality (OR=0.904; p=0.06). Also, fat-free mass correlated with HG strength and cardiac ejection fraction. Malnutrition risk was diagnosed in 45% of the patients, whereas 8 patients met the definition of cachexia. Even without statistical significance, CRS patients with malnutrition had lower BMI (Body Mass Index) (p=0.038) and fat-free mass (p= n.s.). However, CRS malnutrition was associated to higher 6-month mortality (p= 0.05), and appears to negatively influence the outcome in CRS (OR= 9; p= 0.06). Our results show that malnutrition is prevalent in CRS patients and influences the clinical outcome. The assessment of nutritional status, and particularly body composition, should be implemented in daily practice of patients with CRS.

  16. The effect of protein and carbohydrate supplementation on strength training outcome of rehabilitation in ACL patients

    DEFF Research Database (Denmark)

    Holm, Lars; Esmarck, Birgitte; Mizuno, Masao

    2006-01-01

    supplementation groups: Protein+Carbohydrate (PC), Isocaloric-Carbohydrate (IC), or Placebo (PL), ingesting the supplementation immediately after each of 36 training sessions. Determined from images of thigh cross-sections (magnetic resonance imaging) the hypertrophy of the quadriceps muscle differed....... The results from this study demonstrate that restoration of the distal vasti muscle mass and knee extension muscle strength with resistance training is promoted further by protein-containing nutrient supplementation immediately after single exercise sessions. Thus, exercise-related protein supplementation may...... was therefore to investigate if nutrient supplementation during 12 weeks of conservative rehabilitation strength training could enhance hypertrophy and strength of the quadriceps muscle in ACL-injured patients. Twenty-six ACL-injured men and women were included and randomly distributed into three...

  17. Influence of different adhesive systems on the pull-out bond strength of glass fiber posts.

    Science.gov (United States)

    da Silva, Luciana Mendonça; Andrade, Andréa Mello de; Machuca, Melissa Fernanda Garcia; da Silva, Paulo Maurício Batista; da Silva, Ricardo Virgolino C; Veronezi, Maria Cecília

    2008-01-01

    This in vitro study evaluated the tensile bond strength of glass fiber posts (Reforpost - Angelus-Brazil) cemented to root dentin with a resin cement (RelyX ARC - 3M/ESPE) associated with two different adhesive systems (Adper Single Bond - 3M/ESPE and Adper Scotchbond Multi Purpose (MP) Plus - 3M/ESPE), using the pull-out test. Twenty single-rooted human teeth with standardized root canals were randomly assigned to 2 groups (n=10): G1- etching with 37% phosphoric acid gel (3M/ESPE) + Adper Single Bond + #1 post (Reforpost - Angelus) + four #1 accessory posts (Reforpin - Angelus) + resin cement; G2- etching with 37% phosphoric acid gel + Adper Scotchbond MP Plus + #1 post + four #1 accessory posts + resin cement. The specimens were stored in distilled water at 37 degrees C for 7 days and submitted to the pull-out test in a universal testing machine (EMIC) at a crosshead speed of 0.5 mm/min. The mean values of bond strength (kgf) and standard deviation were: G1- 29.163 +/- 7.123; G2- 37.752 +/-13.054. Statistical analysis (Student's t-test; a=0.05 showed no statistically significant difference (pAdhesive bonding failures between resin cement and root canal dentin surface were observed in both groups, with non-polymerized resin cement in the apical portion of the post space when Single Bond was used (G1). The type of adhesive system employed on the fiber post cementation did not influence the pull-out bond strength.

  18. Influence of different adhesive systems on the pull-out bond strength of glass fiber posts

    Directory of Open Access Journals (Sweden)

    Luciana Mendonça da Silva

    2008-06-01

    Full Text Available This in vitro study evaluated the tensile bond strength of glass fiber posts (Reforpost - Angelus-Brazil cemented to root dentin with a resin cement (RelyX ARC - 3M/ESPE associated with two different adhesive systems (Adper Single Bond - 3M/ESPE and Adper Scotchbond Multi Purpose (MP Plus - 3M/ESPE, using the pull-out test. Twenty single-rooted human teeth with standardized root canals were randomly assigned to 2 groups (n=10: G1- etching with 37% phosphoric acid gel (3M/ESPE + Adper Single Bond + #1 post (Reforpost - Angelus + four #1 accessory posts (Reforpin - Angelus + resin cement; G2- etching with 37% phosphoric acid gel + Adper Scotchbond MP Plus + #1 post + four #1 accessory posts + resin cement. The specimens were stored in distilled water at 37°C for 7 days and submitted to the pull-out test in a universal testing machine (EMIC at a crosshead speed of 0.5 mm/min. The mean values of bond strength (kgf and standard deviation were: G1- 29.163 ± 7.123; G2- 37.752 ±13.054. Statistical analysis (Student's t-test; a=0.05 showed no statistically significant difference (p<0.05 between the groups. Adhesive bonding failures between resin cement and root canal dentin surface were observed in both groups, with non-polymerized resin cement in the apical portion of the post space when Single Bond was used (G1. The type of adhesive system employed on the fiber post cementation did not influence the pull-out bond strength.

  19. Analysis of the influence of chemical treatment to the strength and surface roughness of FDM

    Science.gov (United States)

    Hambali, R. H.; Cheong, K. M.; Azizan, N.

    2017-06-01

    The applications of Additive Manufacturing (AM) technology have a greater functionality and wider range of application beyond an intention of prototyping. AM is the process of joining materials to form objects from Computer-Aided Design (CAD) models via layer upon layer process. One of AM technologies is the Fused Deposition Modelling (FDM), which use an extrusion method to create a part. FDM has been applied in many manufacturing applications includes an end-used parts. However, FDM tends to have bad surface quality due to staircase effect and post treatment is required. This chemical treatment is one of a way to improve the surface roughness of FDM fabricated parts. This method is one of economical and faster method. In order to enhance the surface finish of Acrylonitrile-Butadiene-Styrene (ABS) FDM parts by performing chemical treatment in an acetone solution as acetone has very low toxicity, high diffusion and low cost chemical solution. Therefore, the aim of this research is to investigate the influence of chemical treatment to the FDM used part in terms of surface roughness as well as the strength. In this project, ten specimens of standard ASTM D638 dogbone specimens have been fabricated using MOJO 3D printer. Five specimens from the dogbone were tested for surface roughness and tensile testing while another five were immersed in the chemical solution before the same testing. Based on results, the surface roughness of chemically treated dogbone has dramatically improved, compared to untreated dogbone with 97.2% of improvement. However, in term of strength, the tensile strength of dogbone is reduced 42.58% due to the rearrange of material properties and chemical effects to the joining of the filaments. In conclusion, chemical treatment is an economical and sustainable approach to enhance the surface quality of AM parts.

  20. [Chlorine coatings on skin surfaces. II. Parameters influencing the coating strength].

    Science.gov (United States)

    Gottardi, W; Karl, A

    1991-05-01

    Although active chlorine compounds have been used for more than 140 years (Semmelweis, 1848) as a skin disinfectant the phenomenon of the "chlorine covers" not earlier than 1988 has been described for the first time (Hyg. + Med. 13 (1988) 157). It deals with a chemical alteration of the uppermost skin layer which comes apparent in an oxydizing action against aqueous iodide. Its origin is chlorine covalently bound in the form of N-Cl functions to the protein matrix of the horny skin. Since the chlorine covers exhibit a persistant disinfecting activity which might be important for practice, the factors influencing their strength have been established. The most important are: the kind of the chlorine system, the concentration (oxydation capacity), pH, temperature and the volume of the used solution, the time of action, the application technique and the state of the skin. Variations of the latter can be observed at different skin areas of one and the same person as well as at the same areas of different persons, and result in differences of the cover strength up to 100%. The stability on dry skin is very good, showing a decomposition rate of approximately 1.2% per hour. However on skin surfaces moistened by sweat (e.g. hands covered by surgeons gloves) the chlorine cover is disingrated much more faster (decomposition rate: 40-50% per hour). Washing with soap as well as the action of alcohols cause virtually no decrease in the cover strength, while wetting by solutions of reducing agents (e.g. thiosulfate, cysteine, iodide) provokes a fast decomposition suitable for removing the chlorine covers.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Rotational Failure of Rubble-pile Bodies: Influences of Shear and Cohesive Strengths

    Science.gov (United States)

    Zhang, Yun; Richardson, Derek C.; Barnouin, Olivier S.; Michel, Patrick; Schwartz, Stephen R.; Ballouz, Ronald-Louis

    2018-04-01

    The shear and cohesive strengths of a rubble-pile asteroid could influence the critical spin at which the body fails and its subsequent evolution. We present results using a soft-sphere discrete element method to explore the mechanical properties and dynamical behaviors of self-gravitating rubble piles experiencing increasing rotational centrifugal forces. A comprehensive contact model incorporating translational and rotational friction and van der Waals cohesive interactions is developed to simulate rubble-pile asteroids. It is observed that the critical spin depends strongly on both the frictional and cohesive forces between particles in contact; however, the failure behaviors only show dependence on the cohesive force. As cohesion increases, the deformation of the simulated body prior to disruption is diminished, the disruption process is more abrupt, and the component size of the fissioned material is increased. When the cohesive strength is high enough, the body can disaggregate into similar-size fragments, which could be a plausible mechanism to form asteroid pairs or active asteroids. The size distribution and velocity dispersion of the fragments in high-cohesion simulations show similarities to the disintegrating asteroid P/2013 R3, indicating that this asteroid may possess comparable cohesion in its structure and experience rotational fission in a similar manner. Additionally, we propose a method for estimating a rubble pile’s friction angle and bulk cohesion from spin-up numerical experiments, which provides the opportunity for making quantitative comparisons with continuum theory. The results show that the present technique has great potential for predicting the behaviors and estimating the material strengths of cohesive rubble-pile asteroids.

  2. Factors influencing the tensile strength of repaired Achilles tendon: a biomechanical experiment study.

    Science.gov (United States)

    Jielile, Jiasharete; Bai, Jing Ping; Sabirhazi, Gulnur; Redat, Darebai; Yilihamu, Tuoheti; Xinlin, Baoltri; Hu, Geyang; Tang, Bin; Liang, Bing; Sun, Qi

    2010-10-01

    Operative treatment has been advocated as the method of choice to repair Achilles tendon rupture as surgery results in reduced re-rupture rate and faster rehabilitation. Many surgical techniques have been introduced allowing for postoperative early motion of the ankle joint. However, it is currently very difficult for surgeons to determine the optimal treatment conditions for ruptured Achilles tendon with an increasing number of end-to-end suture methods, suture materials, and epitenon suture techniques. In the present biomechanical experiment study based on an orthogonal design, thirty-two New Zealand white rabbits received Achilles tendon tenotomy and subsequent operative treatment to repair the tendon employing four end-to-end suture methods, four suture materials, and four epitenon suture techniques. The tensile strength of the repaired Achilles tendon was investigated at four rehabilitation periods, and in comparison with the results of another sixteen rabbits with normal Achilles tendons. The end-to-end suture method contributed most to the final Achilles tendon tensile strength in addition to rehabilitation period, with the highest values occurring with the use of the parachute-like ("Pa" bone) suture method. The other two factors, namely, suture material and epitenon suture technique, had relatively little influence on the results. The parachute-like ("Pa" bone) surgical technique is superior to the other three end-to-end suture methods, with enhanced tensile strength of the repaired tendon. This method allows for postoperative early kinesitherapy of the ankle and knee joints. Therefore, this technique is highly recommended in clinical situations for treatment of ruptured Achilles tendon. 2010 Elsevier Ltd. All rights reserved.

  3. Influence of Er,Cr: YSGG laser on bond strength of self-adhesive resin cement

    Directory of Open Access Journals (Sweden)

    Matheus Coelho Bandéca

    2012-08-01

    Full Text Available The purpose of this study was to investigate the bond strength of fiber post previously laser treated root canals. Forty single-rooted bovine teeth were endodontically treated, randomly and equally divided into two main groups according to the type of pretreatment: G1: 2.5% NaOCl (control group; and G2: Er,Cr:YSGG laser. Each group was further subdivided into 2 groups based on the category of adhesive systems/ luting materials used: a: an etch-and-rinse resin cement (Single Bond/RelyX ARC; 3M ESPE, and b: a self-adhesive resin cement (Rely X Unicem; 3M ESPE. Three 1.5 mm thick slabs were obtained per root and the push-out test was performed at a crosshead speed of 0.5 mm/min until post dislodgement occurred. Data were analyzed by ANOVA and post-hoc Tukey's test at a pre-set alpha of 0.05. Analysis of variance showed no statistically significant difference (p > 0.05 among the groups G1a (25.44 ± 2.35 and G1b (23.62 ± 3.48, G2a (11.77 ± 2.67 and G2b (9.93 ± 3.37. Fractures were observed at the interface between the dentin and the resin in all groups. The Er,Cr:YSGG laser irradiation did not influence on the bond strength of the resin cements and the etch-and-rinse resin cement had better results on bond strength than self-adhesive resin cement.

  4. Influence of increment thickness on dentin bond strength and light transmission of composite base materials.

    Science.gov (United States)

    Omran, Tarek A; Garoushi, Sufyan; Abdulmajeed, Aous A; Lassila, Lippo V; Vallittu, Pekka K

    2017-06-01

    Bulk-fill resin composites (BFCs) are gaining popularity in restorative dentistry due to the reduced chair time and ease of application. This study aimed to evaluate the influence of increment thickness on dentin bond strength and light transmission of different BFCs and a new discontinuous fiber-reinforced composite. One hundred eighty extracted sound human molars were prepared for a shear bond strength (SBS) test. The teeth were divided into four groups (n = 45) according to the resin composite used: regular particulate filler resin composite: (1) G-ænial Anterior [GA] (control); bulk-fill resin composites: (2) Tetric EvoCeram Bulk Fill [TEBF] and (3) SDR; and discontinuous fiber-reinforced composite: (4) everX Posterior [EXP]. Each group was subdivided according to increment thickness (2, 4, and 6 mm). The irradiance power through the material of all groups/subgroups was quantified (MARC® Resin Calibrator; BlueLight Analytics Inc.). Data were analyzed using two-way ANOVA followed by Tukey's post hoc test. SBS and light irradiance decreased as the increment's height increased (p composite used. EXP presented the highest SBS in 2- and 4-mm-thick increments when compared to other composites, although the differences were not statistically significant (p > 0.05). Light irradiance mean values arranged in descending order were (p composites. Discontinuous fiber-reinforced composite showed the highest value of curing light transmission, which was also seen in improved bonding strength to the underlying dentin surface. Discontinuous fiber-reinforced composite can be applied safely in bulks of 4-mm increments same as other bulk-fill composites, although, in 2-mm thickness, the investigated composites showed better performance.

  5. Influence of disinfectant solutions on the tensile bond strength of a fourth generation dentin bonding agent

    Directory of Open Access Journals (Sweden)

    BOCANGEL Jorge Saldivar

    2000-01-01

    Full Text Available The purpose of the present study was to evaluate the influence of different disinfectant solutions on the tensile bond strength of a fourth generation dentin bonding agent. Forty non carious human molars were selected. Teeth were embedded in acrylic resin and ground until the exposure of a flat superficial dentin surface. Teeth were randomly divided in 4 groups and treated as follows: Group 1 - 2.5% NaOCl for 40 seconds; Group 2 - 2% chlorhexidine for 40 seconds; Group 3 - 1.23% acidulated fluoride for 4 minutes; and Group 4 - control (without disinfectant solution. Following treatments, Scotchbond Multipurpose Plus® (3M was used according to the manufacturer's instructions. After that, the test specimens were built with composite resin (Z100®-3M, using a standard Teflon matrix. The specimens were stored in distilled water for 24 hours at a temperature of 37ºC. The tensile strength test was performed using a Mini Instrom testing machine. The mean values obtained for each group, in MPa, were: Group 1 - 7.37 (± 2.51; Group 2 - 11.25 (± 4.65; Group 3 - 9.80 (± 3.11; and Group 4 - 10.96 (± 3.37. The results were submitted to statistical analysis using the ANOVA test, and no statistical significant differences among the groups were found. It can be concluded that the different disinfectant substances used in this research do not adversely affect dentin adhesion.

  6. Influence of the waste glass in the axial compressive strength of Portland cement concrete

    International Nuclear Information System (INIS)

    Miranda Junior, E.J.P.; Paiva, A.E.M.

    2012-01-01

    In this work, was studied the influence of the incorporation of waste glass, coming from the stage of thinning and polishing of a company of thermal glass treatments, in the axial compressive strength of Portland cement concrete. The coarse and ground aggregates used was crushed stone and sand, respectively. For production of the concrete, percentages of glass residues of 5%, 10% and 20% had been used in substitution to the sand, and relations water/cement (a/c) 0,50, 0,55 and 0,58. The cure of the test bodies was carried through in 7, 14 and 28 days. The statistics analysis of the results was carried out through of the analysis of variance for each one of the cure times. From the results of the compressive strength of the concrete, it could be observed that the concrete has structural application for the relation a/c 0,5, independently of waste glass percentage used, and for the relation a/c 0,55 with 20% of waste glass. (author)

  7. Influence of Pre-etching Times on Fatigue Strength of Self-etch Adhesives to Enamel.

    Science.gov (United States)

    Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Endo, Hajime; Tsuchiya, Kenji; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

    To use shear bond strength (SBS) and shear fatigue strength (SFS) testing to determine the influence of phosphoric acid pre-etching times prior to application of self-etch adhesives on enamel bonding. Two single-step self-etch universal adhesives (Prime&Bond Elect and Scotchbond Universal), a conventional single-step self-etch adhesive (G-ӕnial Bond), and a conventional two-step self-etch adhesive (OptiBond XTR) were used. The SBS and SFS were obtained with phosphoric acid pre-etching for 3, 10, or 15 s prior to application of the adhesives, and without pre-etching (0 s) as a control. A staircase method was used to determine the SFS with 10 Hz frequency for 50,000 cycles or until failure occurred. The mean demineralization depth for each treated enamel surface was also measured using a profilometer. For all the adhesives, the groups with pre-etching showed significantly higher SBS and SFS than groups without pre-etching. However, there was no significant difference in SBS and SFS among groups with > 3 s of preetching. In addition, although the groups with pre-etching showed significantly deeper demineralization depths than groups without pre-etching, there was no significant difference in depth among groups with > 3 s of pre-etching. Three seconds of phosphoric acid pre-etching prior to application of self-etch adhesive can enhance enamel bonding effectiveness.

  8. Polysialates binders preparation and their influence to shear strength of foundry sand mixtures

    Directory of Open Access Journals (Sweden)

    R. Fridrich

    2008-07-01

    Full Text Available This paper deals with polysialates water-glasses preparation. There were used various procedures with the goal to create inorganic polymer on silicon and aluminum base. The one composed of SiO2 and AlO4 tetrahedron chains. For the preparation was concentrated NaOH solution used together with metakaolinite in a way low-temperature synthesis in the presence of alkaline silicate: higher pressure and temperature (autoclave to direct making of alkaline silicate made of sand, NaOH with metakaolinite addition and by melting fritted glass together with metakaolinite and dissolution in autoclave. The dissolving effectivity was evaluated by the concentration of aluminum in alkaline silicate and by the influence to reduce strengths after heat exposition with this inorganic binder.

  9. Muscle strength and regional lean body mass influence on mineral bone health in young male adults.

    Science.gov (United States)

    Guimarães, Bianca Rosa; Pimenta, Luciana Duarte; Massini, Danilo Alexandre; Dos Santos, Daniel; Siqueira, Leandro Oliveira da Cruz; Simionato, Astor Reis; Dos Santos, Luiz Gustavo Almeida; Neiva, Cassiano Merussi; Pessôa Filho, Dalton Muller

    2018-01-01

    The relationship between muscle strength and bone mineral content (BMC) and bone mineral density (BMD) is supposed from the assumption of the mechanical stress influence on bone tissue metabolism. However, the direct relationship is not well established in younger men, since the enhancement of force able to produce effective changes in bone health, still needs to be further studied. This study aimed to analyze the influence of muscle strength on BMC and BMD in undergraduate students. Thirty six men (24.9 ± 8.6 y/o) were evaluated for regional and whole-body composition by dual energy X-ray absorptiometry (DXA). One repetition maximum tests (1RM) were assessed on flat bench-press (BP), lat-pull down (LPD), leg-curl (LC), knee extension (KE), and leg-press 45° (LP45) exercises. Linear regression modelled the relationships of BMD and BMC to the regional body composition and 1RM values. Measurements of dispersion and error (R2adj and standard error of estimate (SEE)) were tested, setting ρ at ≤0.05. The BMD mean value for whole-body was 1.12±0.09 g/cm2 and BMC attained 2477.9 ± 379.2 g. The regional lean mass (LM) in upper-limbs (UL) (= 6.80±1.21 kg) was related to BMC and BMD for UL (R2adj = 0.74, pBMC and BMD for LL (R2adj = 0.68, pBMC (R2adj = 0.47, pBMC (R2adj = 0.36, pBMC and BMD in young men, strengthening the relationship between force and LM, and suggesting both to parametrizes bone mineral health.

  10. Influence of rivet to sheet edge distance on fatigue strength of self-piercing riveted aluminium joints

    OpenAIRE

    Li, Dezhi; Han, Li; Thornton, Martin; Shergold, Mike

    2012-01-01

    Self-piercing riveting (SPR) is one of the main joining methods for lightweight aluminium automotive body structures due to its advantages. In order to further optimise the structure design and reduce the weight but without compromising strength, reduction of redundant materials in the joint flange area can be considered. For this reason, the influence of rivet to sheet edge distance on the fatigue strengths of self-piercing riveted joints was studied. Five edge distances, 5 mm, 6 mm, 8 mm, 1...

  11. Memory strength and lineup presentation moderate effects of administrator influence on mistaken identifications.

    Science.gov (United States)

    Zimmerman, David M; Chorn, Jacqueline Austin; Rhead, Lindsey M; Evelo, Andrew J; Kovera, Margaret Bull

    2017-12-01

    Administrator/witness pairs (N = 313) were randomly assigned to target-absent lineups in a 2 (Suspect/Perpetrator Similarity: High Suspect Similarity vs. Low Suspect Similarity) × 2 (Retention Interval: 30 min vs. 1 week) × 2 (Lineup Presentation: Simultaneous vs. Sequential) × 2 (Administrator Knowledge: Single-Blind vs. Double-Blind) factorial design to test whether suspect similarity and memory strength constrain interpersonal expectancy effects on eyewitness identification accuracy. Administrators who knew which lineup member was the suspect (single-blind) or who administered simultaneous lineups were more likely to emit verbal and nonverbal behaviors that suggested to the witness who the suspect was. Additionally, single-blind administrators exerted more pressure on witnesses to choose the suspect as opposed to fillers. Administrator knowledge interacted with retention interval and lineup presentation to influence mistaken identifications of innocent suspects; witnesses were more likely to mistakenly identify an innocent suspect from single-blind than double-blind lineups when witness retention intervals were long and photographs were presented simultaneously. Contrary to our predictions, suspect/perpetrator similarity did not interact with other manipulated variables to influence identification decisions. Both sequential and double-blind procedures should be used to reduce the use of suggestive behavior during lineup administration. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  12. Measuring outcomes in adult spinal deformity surgery: a systematic review to identify current strengths, weaknesses and gaps in patient-reported outcome measures.

    Science.gov (United States)

    Faraj, Sayf S A; van Hooff, Miranda L; Holewijn, Roderick M; Polly, David W; Haanstra, Tsjitske M; de Kleuver, Marinus

    2017-08-01

    Adult spinal deformity (ASD) causes severe disability, reduces overall quality of life, and results in a substantial societal burden of disease. As healthcare is becoming more value based, and to facilitate global benchmarking, it is critical to identify and standardize patient-reported outcome measures (PROMs). This study aims to identify the current strengths, weaknesses, and gaps in PROMs used for ASD. Studies were included following a systematic search in multiple bibliographic databases between 2000 and 2015. PROMs were extracted and linked to the outcome domains of WHO's International Classification of Functioning and Health (ICF) framework. Subsequently, the clinimetric quality of identified PROMs was evaluated. The literature search identified 144 papers that met the inclusion criteria, and nine frequently used PROMs were identified. These covered 29 ICF outcome domains, which could be grouped into three of the four main ICF chapters: body function (n = 7), activity and participation (n = 19), environmental factors (n = 3), and body structure (n = 0). A low quantity (n = 3) of papers was identified that studied the clinimetric quality of PROMs. The Scoliosis Research Society (SRS)-22 has the highest level of clinimetric quality for ASD. Outcome domains related to mobility and pain were well represented. We identified a gap in current outcome measures regarding neurological and pulmonary function. In addition, no outcome domains were measured in the ICF chapter body structure. These results will serve as a foundation for the process of seeking international consensus on a standard set of outcome domains, accompanied PROMs and contributing factors to be used in future clinical trials and spine registries.

  13. Influence of chlorhexidine concentration on microtensile bond strength of contemporary adhesive systems

    Directory of Open Access Journals (Sweden)

    Edson Alves de Campos

    2009-09-01

    Full Text Available The purpose of this study was to investigate the influence of chlorhexidine (CHX concentration on the microtensile bond strength (μTBS of contemporary adhesive systems. Eighty bovine central incisors were used in this study. The facial enamel surface of the crowns was abraded with 600-grit silicon carbide paper to expose flat, mid-coronal dentin surfaces. The tested materials were Scotchbond Multipurpose (SMP, Single-Bond (SB, Clearfil SE Bond (CSEB and Clearfil Tri S Bond (CTSB. All the materials were applied according to manufacturer's instructions and followed by composite application (Z250. The teeth were randomly divided into 16 groups: for the etch-and-rinse adhesives (SMP and SB, 0.12% or 2% CHX was applied prior to or after the acid etching procedure. For the self-etch adhesives (CSEB and CTSB 0.12% or 2% CHX was applied prior to the primer. Control groups for each one of the adhesive systems were also set up. The specimens were immediately submitted to μTBS testing and the data were analyzed using Analysis of Variance and the Tukey post hoc test (alpha = .01. The failure patterns of the specimens were observed using scanning electron microscopy. The effects of 2% CHX were statistically significant (p < 0.01 for the self-etch adhesives but were not significant for the etch-and-rinse adhesive systems. Analysis of the data demonstrated no statistical difference between the etch-and-rinse adhesive systems. CHX-based cavity disinfectants in concentrations higher than 0.12% should be avoided prior to the self-etch adhesive systems evaluated in this study to diminish the possibilities of reduction in bond strength.

  14. Influence of water storage on fatigue strength of self-etch adhesives.

    Science.gov (United States)

    Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Scheidel, Donal D; Watanabe, Hidehiko; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

    2015-12-01

    The purpose of this study was to determine enamel and dentin bond durability after long-term water storage using self-etch adhesives. Two single step self-etch adhesives (SU, Scotchbond Universal and GB, G-ӕnial Bond) and a two-step self-etch adhesive (OX, OptiBond XTR) were used. The shear bond strength (SBS) and shear fatigue strength (FS) of the enamel and dentin were obtained with and without phosphoric acid pre-etching prior to application of the adhesives. The specimens were stored in distilled water at 37 °C for 24 h, 6 months, and one year. A staircase method was used to determine the FS using a frequency of 10 Hz for 50,000 cycles or until failure occurred. The SBS and FS of enamel bonds were significantly higher with pre-etching, when compared to no pre-etching for the same water storage period. The FS of dentin bonds with pre-etching tended to decrease relative to no pre-etching at the same storage period. For the one year storage period, SU and GB with pre-etching showed significantly lower FS values than the groups without pre-etching. The influence of water storage on FS of the self-etch adhesives was dependent on the adhesive material, storage period and phosphoric acid pre-etching of the bonding site. Phosphoric acid pre-etching of enamel improves the effectiveness of self-etch adhesive systems. Inadvertent contact of phosphoric acid on dentin appears to reduce the ability of self-etch adhesives to effectively bond resin composite materials. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Influences of Fascicle Length During Isometric Training on Improvement of Muscle Strength.

    Science.gov (United States)

    Tanaka, Hiroki; Ikezoe, Tome; Umehara, Jun; Nakamura, Masatoshi; Umegaki, Hiroki; Kobayashi, Takuya; Nishishita, Satoru; Fujita, Kosuke; Araki, Kojiro; Ichihashi, Noriaki

    2016-11-01

    Tanaka, H, Ikezoe, T, Umehara, J, Nakamura, M, Umegaki, H, Kobayashi, T, Nishishita, S, Fujita, K, Araki, K, and Ichihashi, N. Influences of fascicle length during isometric training on improvement of muscle strength. J Strength Cond Res 30(11): 3249-3255, 2016-This study investigated whether low-intensity isometric training would elicit a greater improvement in maximum voluntary contraction (MVC) at the same fascicle length, rather than the joint angle, adopted during training. Sixteen healthy women (21.8 ± 1.5 years) were randomly divided into an intervention group and a control group. Before (Pre) and after (Post) training, isometric plantarflexion MVCs were measured every 10° through the range of ankle joint position from 20° dorsiflexion to 30° plantarflexion (i.e., 6 ankle angles). Medial gastrocnemius fascicle length was also measured at each position, using B-mode ultrasound under 3 conditions of muscle activation: at rest, 30%MVC at respective angles, and MVC. Plantarflexion resistance training at an angle of 20° plantarflexion was performed 3 days a week for 4 weeks at 30%MVC using 3 sets of twenty 3-second isometric contractions. Maximum voluntary contraction in the intervention group increased at 0 and 10° plantarflexion (0°; Pre: 81.2 ± 26.5 N·m, Post: 105.0 ± 21.6 N·m, 10°; Pre: 63.0 ± 23.6 N·m, Post: 81.3 ± 20.3 N·m), which was not the angle used in training (20°). However, the fascicle length adopted in training at 20° plantarflexion and 30%MVC was similar to the value at 0 or 10° plantarflexion at MVC. Low-intensity isometric training at a shortened muscle length may be effective for improving MVC at a lengthened muscle length because of specificity of the fascicle length than the joint angle.

  16. Influence of the mechanical properties of lime mortar on the strength of brick masonry

    OpenAIRE

    PAVIA, SARA

    2013-01-01

    PUBLISHED This paper aims at improving the quality of lime mortar masonry by understanding the mechanics of mortars and masonry and their interaction. It investigates how the mortar?s compressive and flexural strengths impact the compressive and bond strength of clay brick masonry bound with calcium lime (CL) and natural hydraulic lime (NHL) mortars. It concludes that the strength of the bond has a greater impact on the compressive strength of masonry than the mortar?s st...

  17. Systematic reviews: I. The correlation between laboratory tests on marginal quality and bond strength. II. The correlation between marginal quality and clinical outcome.

    Science.gov (United States)

    Heintze, Siegward D

    2007-01-01

    An accepted principle in restorative dentistry states that restorations should be placed with the best marginal quality possible to avoid postoperative sensitivity, marginal discoloration, and secondary caries. Different laboratory methods claim to predict the clinical performance of restorative materials, for example, tests of bond strength and microleakage and gap analysis. The purpose of this review was twofold: (1) find studies that correlated the results of bond strength tests with either microleakage or gap analysis for the same materials, and (2) find studies that correlated the results of microleakage and/or gaps with the clinical parameters for the same materials. Furthermore, influencing factors on the results of the laboratory tests were reviewed and assessed. For the first question, searches for studies were conducted in the MEDLINE database and IADR/AADR abtracts online with specific search and inclusion criteria. The outcome for each study was assessed on the basis of the statistical test applied in the study, and finally the number of studies with or without correlation was compiled. For the second question, results of the quantitative marginal analysis of Class V restorations published by the University of Zürich with the same test protocol and prospective clinical trials were searched that investigated the same materials for at least 2 years in Class V cavities. Pearson correlation coefficients were calculated for pooled data of materials and clinical outcome parameters such as retention loss, marginal discoloration, marginal integrity, and secondary caries. For the correlation of dye penetration and clinical outcome, studies on Class V restorations published by the same research institute were searched in MEDLINE that examined the same adhesive systems as the selected clinical trials. For the correlation bond strength/microleakage, 30 studies were included into the review, and for the correlation bond strength/gap analysis 18 studies. For both

  18. Tensile strength of solution-spun, ultradrawn ultrahigh-molecular-weight polyethylene fibers. 1. Influence of fiber diameter

    OpenAIRE

    Bastiaansen, C.W.M.

    1992-01-01

    The influence of fiber diam. on the tensile strength of soln.-spun, ultradrawn, ultrahigh-mol.-wt. polyethylene (UHMWPE, mol. wt. >103 kg/mol) fibers was studied. Fibers with a wide range of diams. were produced by varying the polymer concn. in soln. and by applying a drawdown to the fibers. The tensile strength of drawn fibers was compared at a const. Young's modulus in order to eliminate the influence of morphol. parameters, such as degree of chain orientation and extension, on the fracture...

  19. CHARACTERIZATION AND PERFORMANCE OF ELEMENTARY HEMP FIBRES: FACTORS INFLUENCING TENSILE STRENGTH

    Directory of Open Access Journals (Sweden)

    Mizi Fan

    2010-09-01

    Full Text Available This paper presents the outcomes from an extensive investigation on the structure and geometry of single hemp fibres, as well as configurations and related tensile strength (TS of hemp fibres, with the aid of field emission scanning and optical microscopy. The results showed that 1 the TS increased with the decrease of the diameter of individual test pieces, due possibly to the stacks of multiple single fibres within the test pieces; 2 shear failure between single fibres in a test pieces played a significant role in the test results; 3 the TS was closely related to the number of both the inherent joints along the fibre length and single fibres contained in the test pieces; 4 the splits along the length and width of hemp fibres may complicate the test results, and 5 the optimized treatment prior to decortications may double the TS of hemp fibres compared to a normal retting processing. Reliable TS of single hemp fibres have been derived by a power regression, and the predicted TS were verified with an excellent agreement with experimentally tested results. The tensile strain-stress plot was found to be linear for all hemp test pieces, showing that the behaviour of single hemp fibres obeys Hooke’s law.

  20. The Influence of Radiographic Severity on the Relationship between Muscle Strength and Joint Loading in Obese Knee Osteoarthritis Patients

    Directory of Open Access Journals (Sweden)

    Jens Aaboe

    2011-01-01

    Full Text Available Objective. To investigate the relationship between knee muscle strength and the external knee adduction moment during walking in obese knee osteoarthritis patients and whether disease severity influences this relationship. Methods. This cross-sectional study included 136 elderly obese (BMI>30 adults with predominant medial knee osteoarthritis. Muscle strength, standing radiographic severity as measured by the Kellgren and Lawrence scale, and the peak external knee adduction moment were measured at self-selected walking speed. Results. According to radiographic severity, patients were classified as “less severe” (KL 1-2, N=73 or “severe” (KL 3-4, N=63. A significant positive association was demonstrated between the peak knee adduction moment and hamstring muscle strength in the whole cohort (P=.047. However, disease severity did not influence the relationship between muscle strength and dynamic medial knee joint loading. Severe patients had higher peak knee adduction moment and more varus malalignment (P<.001. Conclusion. Higher hamstring muscle strength relates to higher estimates of dynamic knee joint loading in the medial compartment. No such relationship existed for quadriceps muscle strength. Although cross sectional, the results suggest that hamstrings function should receive increased attention in future studies and treatments that aim at halting disease progression.

  1. Hormone Replacement and Strength Training Positively Influence Balance During Gait in Post-Menopausal Females: A Pilot Study

    Science.gov (United States)

    Perry, Stephen D.; Bombardier, Eric; Radtke, Alison; Tiidus, Peter M.

    2005-01-01

    This study examined the effects of hormone replacement combined with strength training on improving dynamic balance control in post-menopausal women. Thirty one participating post-menopausal women were divided into three groups (hormone replacement (HR), non-hormone replacement (NR) and control (CR) group). HR and NR groups were tested for muscle strength and balance control during gait, prior to training and following a six week lower body strength training program. Quadriceps muscle strength was evaluated as isokinetic peak torque (60°·sec-1) using a CYBEX NORM and balance control was evaluated by center of mass - base of support relationships and ground reaction forces during gait perturbations. Only the HR group showed significantly (p < 0.05) improved balance control during the initial phase of unexpected gait termination and single stance periods while walking across uneven terrain following training. The strength gains in the HR group tended to be greater than in the NR group over the six week training program, although neither group showed statistically significant increases. The CR group showed no significant differences between testing times. HR in post-menopausal females may enhance dynamic balance control when combined with a strength training program, even if no statistically significant gains in strength are achieved. Key Points This study provides evidence that even a short modest strength training program can enhance dynamic balance control in older adult females taking hormone replacement. If potential benefits of hormone replacement therapy extend to enhancing muscle strength then this would be important in designing optimal interventions for both strength and balance for this cohort. Future work should explore the influence of hormone replacement therapy on other dynamic balance or functional tasks. PMID:24501551

  2. Test-Retest Reliability of Handgrip Strength as an Outcome Measure in Patients With Symptoms of Shoulder Impingement Syndrome.

    Science.gov (United States)

    Savva, Christos; Mougiaris, Paraskevas; Xadjimichael, Christoforos; Karagiannis, Christos; Efstathiou, Michalis

    The purpose of this study was to investigate the degree of test-retest reliability of grip strength measurement using a hand dynamometer in patients with shoulder impingement syndrome. A total of 19 patients (10 women and 9 men; mean ± standard deviation age, 33.2 ± 12.9 years; range 18-59 years) with shoulder impingement syndrome were measured using a hand dynamometer by the same data collector in 2 different testing sessions with a 7-day interval. During each session, patients were encouraged to exert 3 maximal isometric contractions on the affected hand and the mean value of the 3 efforts (measured in kilogram-force [Kgf]) was used for data analysis. The intraclass correlation coefficient (ICC 2,1 ) as well as the standard error of measurement (SEM) and Bland-Altman plot were used to estimate the degree of test-retest reliability and the measurement error, respectively. Grip strength data analysis revealed an ICC 2,1 score of 0.94, which, based on the Shrout classification, is considered as excellent test-retest reliability of grip strength measurement. The small values of SEMs reported in both sessions (SEM 1 , 2.55 Kgf; SEM 2 , 2.39 Kgf) and the small width of the 95% limits of agreement in the Bland-Altman plot (ranging from -7.39 Kgf to 7.03 Kgf) reflected the measurement precision and the narrow variation of the differences during the 2 testing sessions. Results from this study identified excellent test-retest reliability of grip strength measurement in shoulder impingement syndrome, indicating its potential use as an outcome measure in clinical practice. Copyright © 2018. Published by Elsevier Inc.

  3. Influence of the level of speed-strength preparedness on the agility of volleyball players 12–13 years old

    Directory of Open Access Journals (Sweden)

    Oleg Shevchenko

    2018-02-01

    Full Text Available Purpose: determine the impact level of indicators of speed-strength preparedness for the agility of young volleyball players 12–13 years. Material & Methods: analysis of scientific and methodological literature, pedagogical testing of speed-strength qualities and agility, pedagogical experiment, methods of mathematical statistics. The study involved 25 volleyball players aged 12–13 years, training in the basic training group of the second year of training of the sports club "Lokomotiv" in Kharkov. Young athletes were divided into an experimental – 13 people and a control –12 volleyball team. Results: after the introduction of the experimental methodology, a link was found between the level of speed-strength abilities and the agility of volleyball players. Conclusion: the positive influence of development of speed-strength qualities on indicators of agility of volleyball players that is necessary for selection of means and methods in training process of young athletes is proved.

  4. Rheological Properties of Very High-Strength Portland Cement Pastes: Influence of Very Effective Superplasticizers

    Directory of Open Access Journals (Sweden)

    Adriano Papo

    2010-01-01

    Full Text Available The influence of the addition of very effective superplasticizers, that are commercially available, employed for maximising the solid loading of very high-strength Portland cement pastes, has been investigated. Cement pastes were prepared from deionized water and a commercially manufactured Portland cement (Ultracem 52.5 R. Cement and water were mixed with a vane stirrer according to ASTM Standard C305. The 0.38 to 0.44 water/cement ratio range was investigated. Three commercial superplasticizing agents produced by Ruredil S.p.a. were used. They are based on a melamine resin (Fluiment 33 M, on a modified lignosulphonate (Concretan 200 L, and on a modified polyacrylate (Ergomix 1000. Rheological tests were performed at 25°C by using the rate controlled coaxial cylinder viscometer Rotovisko-Haake 20, system M5-osc., measuring device MV2P with serrated surfaces. The tests were carried out under continuous flow conditions. The results of this study were compared with those obtained in a previous article for an ordinary Portland cement paste.

  5. Influence of Adhesives and Methods of Enamel Pretreatment on the Shear Bond Strength of Orthodontic Brackets.

    Science.gov (United States)

    Jurišić, Sanja; Jurišić, Gordan; Jurić, Hrvoje

    2015-12-01

    The objective of present study was to examine influence of adhesives and methods of enamel pretreatment on the shear bond strength (SBS) of orthodontic brackets. The adhesives used were resin-reinforced glass ionomer cements-GIC (Fuji Ortho LC) and composite resin (Transbond XT). The experimental sample consisted of 80 extracted human first premolars. The sample was divided into four equal groups, and the metal brackets were bonded with different enamel pretreatments by using two adhesives: group A-10% polyacrylic acid; Fuji Ortho LC, group B-37% phosphoric acid; Fuji Ortho LC, group C-self etching primer; Transbond XT, group D-37% phosphoric acid, primer; Transbond XT. SBS of brackets was measured. After debonding of brackets, the adhesive remnant index (ARI) was evaluated. After the statistical analysis of the collected data was performed (ANOVA; Sheffe post-hoc test), the results showed that significantly lower SBS of the group B was found in relation to the groups C (p=0.031) and D (p=0.026). The results of ARI were similar in all testing groups and it was not possible to determine any statistically significant difference of the ARI (Chi- square test) between all four experimental groups. The conclusion is that the use of composite resins material with appropriate enamel pretreatment according to manufacturer's recommendation is the "gold standard" for brackets bonding for fixed orthodontic appliances.

  6. Influence of grain structure on quench sensitivity relative to localized corrosion of high strength aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, ShengDan, E-mail: csuliusd@163.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha 410083 (China); Li, ChengBo [Light Alloy Research Institute, Central South University, Changsha 410083 (China); Deng, YunLai; Zhang, XinMing [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha 410083 (China)

    2015-11-01

    The influence of grain structure on quench sensitivity relative to localized corrosion of high strength aluminum alloy 7055 was investigated by electrochemical test, accelerated exfoliation corrosion test, optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The decrease of quench rate led to lower corrosion resistance of both the homogenized and solution heat treated (HS) alloy with equiaxed grains and the hot-rolled and solution heat treated (HRS) alloy with elongated grains, but there was a higher increment in corrosion depth and corrosion current density and a higher decrement in corrosion potential for the latter alloy, which therefore exhibited higher quench sensitivity. It is because in this alloy the larger amount of (sub) grain boundaries led to a higher increment in the amount of quench-induced η phase and precipitates free zone at (sub) grain boundaries with the decrease of quench rate, and there was a larger increment in the content of Zn, Mg and Cu in the η phase at grain boundaries due to slow quenching. The presence of subgrain boundaries in the HRS alloy tended to increase corrosion resistance at high quench rates higher than about 630 °C/min but decrease it at lower quench rates. - Highlights: • (Sub)Grain boundaries increase quench sensitivity relative to localized corrosion. • Subgrain boundaries decrease corrosion resistance below quench rate of 630 °C/min. • More (sub) grain boundaries leads to more GBPs and PFZ with decreasing quench rate.

  7. Influence of nanoporous structure on mechanical strength of aluminium and aluminium alloy adhesive structural joints

    International Nuclear Information System (INIS)

    Spadaro, C; Dispenza, C; Sunseri, C

    2006-01-01

    The influence of surface treatments on the mechanical strength of adhesive joints was investigated. The attention was focused on AA2024 alloy because it is extensively used in both the automotive and aerospace industries. Adhesive joints fabricated with pure aluminium were also investigated in order to evidence possible differences in the surface features after identical treatments. Before joining with a commercial epoxy adhesive, metal substrates were subjected to different kinds of treatment and the surfaces were characterized by SEM analysis. The formation of a microporous surface in the AA2024 alloy, upon etching and anodizing, is discussed on the basis of the role of the intermetallic particles and their electrochemical behaviour with respect to the aluminium matrix. Moreover, nanostructured porous oxide layers on both type of substrate were also formed, as a consequence of the anodizing process. Differences in their morphologies were revealed as a function of both the applied voltage and the presence of alloying elements. On this basis, an explanation of the different values of fracture energy measured by means of T-peel tests carried out on the corresponding joints was attempted

  8. Influence of fall related factors and bone strength on fracture risk in the frail elderly.

    Science.gov (United States)

    Sambrook, P N; Cameron, I D; Chen, J S; Cumming, R G; Lord, S R; March, L M; Schwarz, J; Seibel, M J; Simpson, J M

    2007-05-01

    When subjects are selected on the basis of fall risk alone, therapies for osteoporosis have not been effective. In a prospective study of elderly subjects at high risk of falls, we investigated the influence of bone strength and fall risk on fracture. At baseline we assessed calcaneal bone ultrasound attenuation (BUA) as well as quantitative measures of fall risk in 2005 subjects in residential care. Incident falls and fractures were recorded (median follow-up 705 days). A total of 6646 fall events and 375 low trauma fracture events occurred. The fall rate was 214 per 100 person years and the fracture rate 12.1 per 100 person years. 82% of the fractures could be attributed to falls. Although fracture rates increased with decreasing BUA (incidence rate ratio 1.94 for lowest vs. highest BUA tertile, pfalls also affected fracture incidence. Subjects who fell frequently (>3.15 falls/per person year) were 3.35 times more likely to suffer a fracture than those who did not fall. Some fall risk factors such as balance were associated with the lowest fracture risk lowest in the worst performing group. Multivariate analysis revealed higher fall rate, history of previous fracture, lower BUA, lower body weight, cognitive impairment and better balance as significant independent risk factors for fracture. In the frail elderly, both skeletal fragility and fall risk including the frequency of exposure to falls are important determinants of fracture risk.

  9. Influence of aluminium sheet surface modification on the self-piercing riveting process and the joint static lap shear strength

    OpenAIRE

    Li, Dezhi

    2017-01-01

    Self-piercing riveting (SPR) has been widely used in automotive as one of the major joining technologies for aluminium structures due to its advantages over some of the more traditional joining technologies. Research has shown that friction is a very important factor that influences both the riveting process and the joint strength for SPR, but these influences have not been fully understood. In this paper, AA5754 sheets with different surface textures, such as original with solid wax, hot wat...

  10. The influence of aggregates type on W/C ratio on the strength and other properties of concrete

    Science.gov (United States)

    Malaiskiene, J.; Skripkiunas, G.; Vaiciene, M.; Karpova, E.

    2017-10-01

    The influence of different types of aggregates and W/C ratio on concrete properties is analysed. In order to achieve this aim, lightweight (with expanded clay aggregate) and normal concrete (with gravel aggregate) mixtures are prepared with different W/C ratios. Different W/C ratios are selected by reducing the amount of cement when the amount of water is constant. The following properties of concrete have been determined: density, compressive strength and water absorption. Additionally, the statistical data analysis is performed and influence of aggregate type and W/C ratio on concrete properties is determined. The empirical equations indicating dependence between concrete strength and W/C and strength of aggregate are obtained for normal concrete and light-weight concrete.

  11. Genetic Variation in the Dopamine System Influences Intervention Outcome in Children with Cerebral Palsy

    Directory of Open Access Journals (Sweden)

    Rochellys Diaz Heijtz

    2018-02-01

    Interpretation: Naturally occurring genetic variation in the dopamine system can influence treatment outcomes in children with cerebral palsy. A polygenic dopamine score might be valid for treatment outcome prediction and for designing individually tailored interventions for children with cerebral palsy.

  12. Personality traits in bipolar disorder and influence on outcome.

    Science.gov (United States)

    Sparding, Timea; Pålsson, Erik; Joas, Erik; Hansen, Stefan; Landén, Mikael

    2017-05-03

    The aim was to investigate the personality profile of bipolar disorder I and II, and healthy controls, and to study whether personality influences the course of bipolar disorder. One hundred ten patients with bipolar disorder I, 85 patients with bipolar disorder II, and 86 healthy individuals had their personality profile assessed using the Swedish universities Scales of Personality (SSP), an instrument developed to explore personality-related vulnerabilities and correlates of psychiatric disorders. Patients were followed prospectively for 2 years. To assess the impact of Neuroticism, Aggressiveness, and Disinhibition on illness course, we performed logistic regressions with the outcome variables mood episodes (depressive, hypo/manic, mixed), suicide attempts, violence, and the number of sick leave days. Bipolar disorder I and II demonstrated higher global measures of Neuroticism, Aggressiveness, and Disinhibition as compared with healthy controls. A third of the patients scored ≥1 SD above the population-based normative mean on the global neuroticism measure. The two subtypes of bipolar disorder were, however, undistinguishable on all of the personality traits. In the unadjusted model, higher neuroticism at baseline predicted future depressive episodes and suicide attempts/violent behavior, but this association disappeared when adjusting for baseline depressive symptoms as assessed with MADRS. A significant minority of the patients scored ≥1 SD above the population mean on the global measures of Neuroticism, Aggressiveness and Disinhibition; scores this high are usually evident clinically. Yet, the personality profile does not seem to have prognostic value over a 2-year period.

  13. On Loosening Plastic Composite under Active Load and Its Influence on the Deformation and Strength Properties

    Directory of Open Access Journals (Sweden)

    K. F. Komkov

    2015-01-01

    Full Text Available Processing the test results of the composite, which is a mechanical mixture of metal particles with a plastic polymer binder, has shown that its deformation and strength properties are substantially different from those of stable plastic material. The specimen tests for tensile and compression with measuring transverse deformations, as well as torsion tests of tubular samples have revealed that the process of its deformation is accompanied by a change in the original structure.The composite instability is caused by the fact that during this process, it acquires considerable loosening that depends on the type of the stress-state. Hard metal particles are hardly deformed at any stress-state, but they form a layer of bonds that affect the mixture behavior under force action. The total deformation is the plastic flow of the binder on which deformation, caused both by sliding and by loss of the surface layer bonds, is superimposed.The analysis shows that with destruction at tensile test the non-linear part of the bulk deformation (dilatancy is 6 times more than "conditionally" elastic (3.5 times compressed. The objective of this work is to develop a technique for determining a dilatancy, define its influence on deformation and strength properties of the composite, and improve the mathematical model of the material. The proposed model based on the tensor-nonlinear equations describes loosening, as an additional component of the mean deformation and as a mean stress component, hereinafter referred to as: the first - by the deformation, the second – by the stress. A ratio value of the nonlinear part of deformation with the quadratic tensor argument to the linear part, which reaches 0.3, shows the need for such equations. It also shows the influence of deformation on the relationship between the deviators.To enhance capabilities of mathematical model is possible after including therein the equations for the spherical part of the tensor of deformation

  14. Influence of strength on magnitude and mechanisms of adaptation to power training.

    Science.gov (United States)

    Cormie, Prue; McGuigan, Michael R; Newton, Robert U

    2010-08-01

    To determine whether the magnitude of performance improvements and the mechanisms driving adaptation to ballistic power training differ between strong and weak individuals. Twenty-four men were divided into three groups on the basis of their strength level: stronger (n = 8, one-repetition maximum-to-body mass ratio (1RM/BM) = 1.97 +/- 0.08), weaker (n = 8, 1RM/BM = 1.32 +/- 0.14), or control (n = 8, 1RM/BM = 1.37 +/- 0.13). The stronger and weaker groups trained three times per week for 10 wk. During these sessions, subjects performed maximal-effort jump squats with 0%-30% 1RM. The impact of training on athletic performance was assessed using a 2-d testing battery that involved evaluation of jump and sprint performance as well as measures of the force-velocity relationship, jumping mechanics, muscle architecture, and neural drive. Both experimental groups showed significant (P < or = 0.05) improvements in jump (stronger: peak power = 10.0 +/- 5.2 W.kg, jump height = 0.07 +/- 0.04 m; weaker: peak power = 9.1 +/- 2.3 W.kg, jump height = 0.06 +/- 0.04 m) and sprint performance after training (stronger: 40-m time = -2.2% +/- 2.0%; weaker: 40-m time = -3.6% +/- 2.3%). Effect size analyses revealed a tendency toward practically relevant differences existing between stronger and weaker individuals in the magnitude of improvements in jump performance (effect size: stronger: peak power = 1.55, jump height = 1.46; weaker: peak power = 1.03, jump height = 0.95) and especially after 5 wk of training (effect size: stronger: peak power = 1.60, jump height = 1.59; weaker: peak power = 0.95, jump height = 0.61). The mechanisms driving these improvements included significant (P < or = 0.05) changes in the force-velocity relationship, jump mechanics, and neural activation, with no changes to muscle architecture observed. The magnitude of improvements after ballistic power training was not significantly influenced by strength level. However, the training had a tendency toward

  15. Ceramic microsieves: influence of perforation shape and distribution on flow resistance and membrane strength

    NARCIS (Netherlands)

    Kuiper, S.; Brink, R.; Nijdam, W.; Krijnen, Gijsbertus J.M.; Elwenspoek, Michael Curt

    2002-01-01

    Ceramic microsieves with slit-shaped perforations were compared to sieves with circular-shaped perforations, regarding flow resistance and membrane strength. Destructive tests show that the highest strength is obtained if the perforations are placed in a non-alternating pattern. Especially for

  16. The influence of particles of a minor component on the matrix strength of sodium chloride

    NARCIS (Netherlands)

    Van Veen, B.; van der Voort Maarschalk, Kees; Bolhuis, G.K; Gons, M.; Zuurman, K.; Frijlink, H.W

    2002-01-01

    This paper deals with the matrix strength of sodium chloride particles in pure sodium chloride tablets and in tablets compressed from binary mixtures of sodium chloride with low concentrations of pregelatinised starch. Because this study concerns the strength of the sodium chloride matrix, the

  17. The influence of size and structure of metal orthodontic bracket base on bond strength on tooth enamel

    Directory of Open Access Journals (Sweden)

    Mitić Vladimir

    2009-01-01

    Full Text Available Introduction. The factors which may influence the bond strength of the applied orthodontic brackets on the tooth surface are the size and structure of the bracket base. Objective. The aim of the paper was to investigate the influence of size and shape of different types of brackets on bond strength on the enamel and analyze the remaining quality of adhesive material on the tooth surface after debonding of orthodontic brackets (adhesive remnant index - ARI. Methods. In this study, three types of metal brackets of different sizes and shapes of Dentaurum manufacturer were used (Utratrimm, Equilibrium 2, Discovery, Dentaurum, Inspringen, Germany. The brackets were applied onto the middle part of the anatomic crowns of buccal surfaces of 30 premolars extracted for orthodontic reasons. In addition, the pre-treatment of teeth by 37% orthophosphoric acid and adhesive material System1+ (Dentaurum, Germany were used. Results. The mean value of the bonded brackets bond strength of Discovery type after debonding was 8.67±0.32 MPa, while the value of the bonded brackets bond strength of Equilibrium 2 type amounted to 8.62±0.22 MPa. The value of the bonded brackets bond strength of Ultratrimm type after debonding was 8.22±0.49 MPa. There were no statistical differences in the values of bond strength regarding all three groups of the investigated orthodontic brackets (F=4.56; p<0.05. Conclusion. The base size and design of metal orthodontic brackets did not play a significant role in bond strength, while the values of ARI index were identical in all three investigated groups.

  18. Influence of Curing Age and Mix Composition on Compressive Strength of Volcanic Ash Blended Cement Laterized Concrete

    Directory of Open Access Journals (Sweden)

    Babafemi A.J.

    2012-01-01

    Full Text Available This study investigates the influence of curing age and mix proportions on the compressive strength of volcanic ash (VA blended cement laterized concrete. A total of 288 cubes of 100mm dimensions were cast and cured in water for 3, 7, 28, 56, 90 and 120 days of hydration with cement replacement by VA and sand replacement by laterite both ranging from 0 to 30% respectively while a control mix of 28-day target strength of 25N/mm2 (using British Method was adopted. The results show that the compressive strength of the VA-blended cement laterized concrete increased with the increase in curing age but decreased as the VA and laterite (LAT contents increased. The optimum replacement level was 20%LAT/20%VA. At this level the compressive strength increased with curing age at a decreasing rate beyond 28 days. The target compressive strength of 25N/mm2 was achieved for this mixture at 90 days of curing. VA content and curing age was noted to have significant effect (α ≤ 0.5 on the compressive strength of the VA-blended cement laterized concrete.

  19. Influence of warm air-drying on enamel bond strength and surface free-energy of self-etch adhesives.

    Science.gov (United States)

    Shiratsuchi, Koji; Tsujimoto, Akimasa; Takamizawa, Toshiki; Furuichi, Tetsuya; Tsubota, Keishi; Kurokawa, Hiroyasu; Miyazaki, Masashi

    2013-08-01

    We examined the effect of warm air-drying on the enamel bond strengths and the surface free-energy of three single-step self-etch adhesives. Bovine mandibular incisors were mounted in self-curing resin and then wet ground with #600 silicon carbide (SiC) paper. The adhesives were applied according to the instructions of the respective manufacturers and then dried in a stream of normal (23°C) or warm (37°C) air for 5, 10, and 20 s. After visible-light irradiation of the adhesives, resin composites were condensed into a mold and polymerized. Ten samples per test group were stored in distilled water at 37°C for 24 h and then the bond strengths were measured. The surface free-energies were determined by measuring the contact angles of three test liquids placed on the cured adhesives. The enamel bond strengths varied according to the air-drying time and ranged from 15.8 to 19.1 MPa. The trends for the bond strengths were different among the materials. The value of the γS⁺ component increased slightly when drying was performed with a stream of warm air, whereas that of the γS⁻ component decreased significantly. These data suggest that warm air-drying is essential to obtain adequate enamel bond strengths, although increasing the drying time did not significantly influence the bond strength. © 2013 Eur J Oral Sci.

  20. Does national expenditure on research and development influence stroke outcomes?

    Science.gov (United States)

    Kim, Young Dae; Jung, Yo Han; Norrving, Bo; Ovbiagele, Bruce; Saposnik, Gustavo

    2017-10-01

    Background Expenditure on research and development is a macroeconomic indicator representative of national investment. International organizations use this indicator to compare international research and development activities. Aim We investigated whether differences in expenditures on research and development at the country level may influence the incidence of stroke and stroke mortality. Methods We compared stroke metrics with absolute amount of gross domestic expenditure on R&D (GERD) per-capita adjusted for purchasing power parity (aGERD) and relative amount of GERD as percent of gross domestic product (rGERD). Sources included official data from the UNESCO, the World Health Organization, the World Bank, and population-based studies. We used correlation analysis and multivariable linear regression modeling. Results Overall, data on stroke mortality rate and GERD were available from 66 countries for two periods (2002 and 2008). Age-standardized stroke mortality rate was associated with aGERD (r = -0.708 in 2002 and r = -0.730 in 2008) or rGERD (r = -0.545 in 2002 and r = -0.657 in 2008) (all p < 0.001). Multivariable analysis showed a lower aGERD and rGERD were independently and inversely associated with higher stroke mortality (all p < 0.05). The estimated prevalence of hypertension, diabetes, or obesity was higher in countries with lower aGERD. The analysis of 27 population-based studies showed consistent inverse associations between aGERD or rGERD and incident risk of stroke and 30-day case fatality. Conclusions There is higher stroke mortality among countries with lower expenditures in research and development. While this study does not prove causality, it suggests a potential area to focus efforts to improve global stroke outcomes.

  1. Influence of diabetes mellitus on heart failure risk and outcome

    Directory of Open Access Journals (Sweden)

    Van Belle Eric

    2003-01-01

    Full Text Available Abstract Our aim is to summarize and discuss the recent literature linking diabetes mellitus with heart failure, and to address the issue of the optimal treatment for diabetic patients with heart failure. The studies linking diabetes mellitus (DM with heart failure (HF The prevalence of diabetes mellitus in heart failure populations is close to 20% compared with 4 to 6% in control populations. Epidemiological studies have demonstrated an increased risk of heart failure in diabetics; moreover, in diabetic populations, poor glycemic control has been associated with an increased risk of heart failure. Various mechanisms may link diabetes mellitus to heart failure: firstly, associated comorbidities such as hypertension may play a role; secondly, diabetes accelerates the development of coronary atherosclerosis; thirdly, experimental and clinical studies support the existence of a specific diabetic cardiomyopathy related to microangiopathy, metabolic factors or myocardial fibrosis. Subgroup analyses of randomized trials demonstrate that diabetes is also an important prognostic factor in heart failure. In addition, it has been suggested that the deleterious impact of diabetes may be especially marked in patients with ischemic cardiomyopathy. Treatment of heart failure in diabetic patients The knowledge of the diabetic status may help to define the optimal therapeutic strategy for heart failure patients. Cornerstone treatments such as ACE inhibitors or beta-blockers appear to be uniformly beneficial in diabetic and non diabetic populations. However, in ischemic cardiomyopathy, the choice of the revascularization technique may differ according to diabetic status. Finally, clinical studies are needed to determine whether improved metabolic control might favorably influence the outcome of diabetic heart failure patients.

  2. Temperature and ionic strength influences on actinide(VI)/(V) redox potentials for carbonate limiting complexes

    International Nuclear Information System (INIS)

    Capdevila, H.; Vitorge, P.

    1998-01-01

    Actinide behaviour was studied in two limiting aqueous solutions: acidic and carbonate. Cyclic voltametry was validated with well-known U redox system. SIT was used to account for I influence. Taylor's series expansions to the second order were used to account for T influence. Redox potentials of actinide couples had previously been measured in non complexing media. The above data treatments give standard values for redox potential E 0 , for the corresponding entropy ΔS 0 , enthalpy ΔH 0 and heat capacity ΔC p 0 changes, and also for the corresponding excess values (i.e. the variation of these thermodynamic constants with ionic strength). This methodology was here used in carbonate media to measure the potential of the redox couple PuO 2 (CO 3 ) 3 4- /PuO 2 (CO 3 ) 3 5- from 5 to 70 degC and from I = 0.5 to 4.5 M in Na 2 CO 3 , NaClO 4 media. Experimental details and full results are given for Pu. Only final results are given for Np. Previous and/or published data for U and Am are discussed. E and ΔS variations with T or I were enough to be measured. The values obtained for the fitted SIT coefficients Δε, and for ΔS and ΔCp are similar for U, Np and Pu redox reactions. Using this analogy for Am missing data is discussed. β 3 V /β 3 VI formation constant ratio of the carbonate limiting complexes were deduced from the potential shift from complexing to non complexing media for the Actinide(VI)/Actinide(V) redox couples. β 3 V (U and Pu) and β 3 VI (Np) were finally proposed using published β3 VI (U and Pu) and β 3 V (Np). For Am, this data treatment was used to discuss the AmO 2 2+ / AmO 2 + redox potential

  3. Preoperative opioid strength may not affect outcomes of anterior cervical procedures: a post hoc analysis of 2 prospective, randomized trials

    Science.gov (United States)

    Kelly, Michael P.; Anderson, Paul A.; Sasso, Rick C.; Riew, K. Daniel

    2015-01-01

    Object The aim of this study is to evaluate the relationship between preoperative opioid strength and outcomes of anterior cervical decompressive surgery. Methods A retrospective cohort of 1004 patients enrolled in 1 of 2 investigational device exemption studies comparing cervical total disc arthroplasty (TDA) and anterior cervical discectomy and fusion (ACDF) for single-level cervical disease causing radiculopathy or myelopathy was selected. At a preoperative visit, opioid use data, Neck Disability Index (NDI) scores, 36-ltem Short-Form Health Survey (SF-36) scores, and numeric rating scale scores for neck and arm pain were collected. Patients were divided into strong (oxycodone/morphine/meperidine), weak (codeine/propoxyphene/ hydrocodone), and opioid-naïve groups. Preoperative and postoperative (24 months) outcomes scores were compared within and between groups using the paired t-test and ANCOVA, respectively. Results Patients were categorized as follows: 226 strong, 762 weak, and 16 opioid naïve. The strong and weak groups were similar with respect to age, sex, race, marital status, education level, Worker's Compensation status, litigation status, and alcohol use. At 24-month follow-up, no differences in change in arm or neck pain scores (arm: strong –52.3, weak –50.6, naïve –54.0, p = 0.244; neck: strong –52.7, weak –50.8, naïve –44.6, p = 0.355); NDI scores (strong –36.0, weak –33.3, naïve –32.3, p = 0.181); or SF-36 Physical Component Summary scores (strong: 14.1, weak 13.3, naïve 21.7, p = 0.317) were present. Using a 15-point improvement in NDI to determine success, the authors found no between-groups difference in success rates (strong 80.6%, weak 82.7%, naïve 73.3%, p = 0.134). No difference existed between treatment arms (TDA vs ACDF) for any outcome at any time point. Conclusions Preoperative opioid strength did not adversely affect outcomes in this analysis. Careful patient selection can yield good results in this patient

  4. Influence of periodontal ligament simulation on bond strength and fracture resistance of roots restored with fiber posts

    Directory of Open Access Journals (Sweden)

    Ana Maria Estivalete MARCHIONATTI

    2014-10-01

    Full Text Available Objective: Considering that periodontal ligament simulation may influence the stress distribution over teeth restored with intraradicular retainers, this study aimed to assess the combined effect of mechanical cycling and periodontal ligament simulation on both the bond strength between fiber posts and root dentin and the fracture resistance of teeth restored using glass fiber posts. Material and Methods: Ninety roots were randomly distributed into 3 groups (n=10 (C-MC: control; P-MC: polyether; AS-MC: addition silicone to test bond strength and 6 groups (n=10 (C: control; P: polyether; AS: addition silicone, without mechanical cycling, and C-MC, P-MC and AS-MC with mechanical cycling to test fracture strength, according to the material used to simulate the periodontal ligament. For the bond strength test, fiber posts were cemented, cores were built, mechanical cycling was applied (2×106 cycles, 88 N, 2.2 Hz, and 45º incline, and the teeth cut into 3 slices (2 mm, which were then subjected to the push-out test at 1 mm/min. For the fracture strength test, fiber posts were cemented, cores were built, and half of the groups received mechanical cycling, followed by the compressive strength (45° to the long axis and 1 mm/min performed on all groups. Results: Periodontal ligament simulation did not affect the bond strength (p=0.244 between post and dentin. Simulation of periodontal ligament (p=0.153 and application of mechanical cycling (p=0.97 did not affect fracture resistance. Conclusions: The materials used to simulate the periodontal ligament did not affect fracture or bond strength, therefore periodontal ligament simulation using the tested materials could be considered optional in the conditions of the study.

  5. Responsiveness of performance-based outcome measures for mobility, balance, muscle strength and manual dexterity in adults with myotonic dystrophy type 1.

    Science.gov (United States)

    Kierkegaard, Marie; Petitclerc, Émilie; Hébert, Luc J; Mathieu, Jean; Gagnon, Cynthia

    2018-02-28

    To assess changes and responsiveness in outcome measures of mobility, balance, muscle strength and manual dexterity in adults with myotonic dystrophy type 1. A 9-year longitudinal study conducted with 113 patients. The responsiveness of the Timed Up and Go test, Berg Balance Scale, quantitative muscle testing, grip and pinch-grip strength, and Purdue Pegboard Test was assessed using criterion and construct approaches. Patient-reported perceived changes (worse/stable) in balance, walking, lower-limb weakness, stair-climbing and hand weakness were used as criteria. Predefined hypotheses about expected area under the receiver operating characteristic curves (criterion approach) and correlations between relative changes (construct approach) were explored. The direction and magnitude of median changes in outcome measures corresponded with patient-reported changes. Median changes in the Timed Up and Go test, grip strength, pinch-grip strength and Purdue Pegboard Test did not, in general, exceed known measurement errors. Most criterion (72%) and construct (70%) approach hypotheses were supported. Promising responsiveness was found for outcome measures of mobility, balance and muscle strength. Grip strength and manual dexterity measures showed poorer responsiveness. The performance-based outcome measures captured changes over the 9-year period and responsiveness was promising. Knowledge of measurement errors is needed to interpret the meaning of these longitudinal changes.

  6. Influences of Gd on the microstructure and strength of Mg-4.5Zn alloy

    International Nuclear Information System (INIS)

    Yang Jie; Xiao Wenlong; Wang Lidong; Wu Yaoming; Wang Limin; Zhang Hongjie

    2008-01-01

    Microstructure and mechanical properties of peak-aged Mg-4.5Zn-xGd (x 0, 0.5, 1.0 and 1.5 wt.%) alloys have been investigated. The results showed that the grain size of the alloys was refined gradually with increasing Gd. Mg 5 Gd and Mg 3 Gd 2 Zn 3 phases were found in the Gd-containing alloys. The strengths were greatly improved with Gd additions, and the highest strength level was obtained in the Mg-4.5Zn-1.5Gd alloy, in which the ultimate tensile strength and yield strength were 231 MPa and 113 MPa, respectively. Through comparing with the Mg-4.5Zn alloy, the increments of ultimate tensile strength and yield strength were 22 MPa and 56 MPa, respectively. The improved strength was mainly correlated to the grain refining effect, the strengthening effect of the Mg 5 Gd and Mg 3 Gd 2 Zn 3 phases and also the hardening effect of the solutioned Gd atoms

  7. Influence of application methods of one-step self-etching adhesives on microtensile bond strength

    Directory of Open Access Journals (Sweden)

    Chul-Kyu Choi,

    2011-05-01

    Full Text Available Objectives The purpose of this study was to evaluate the effect of various application methods of one-step self-etch adhesives to microtensile resin-dentin bond strength. Materials and Methods Thirty-six extracted human molars were used. The teeth were assigned randomly to twelve groups (n = 15, according to the three different adhesive systems (Clearfil Tri-S Bond, Adper Prompt L-Pop, G-Bond and application methods. The adhesive systems were applied on the dentin as follows: 1 The single coating, 2 The double coating, 3 Manual agitation, 4 Ultrasonic agitation. Following the adhesive application, light-cure composite resin was constructed. The restored teeth were stored in distilled water at room temperature for 24 hours, and prepared 15 specimens per groups. Then microtensile bond strength was measured and the failure mode was examined. Results Manual agitation and ultrasonic agitation of adhesive significantly increased the microtensile bond strength than single coating and double coating did. Double coating of adhesive significantly increased the microtensile bond strength than single coating did and there was no significant difference between the manual agitation and ultrasonic agitation group. There was significant difference in microtensile bonding strength among all adhesives and Clearfil Tri-S Bond showed the highest bond strength. Conclusions In one-step self-etching adhesives, there was significant difference according to application methods and type of adhesives. No matter of the material, the manual or ultrasonic agitation of the adhesive showed significantly higher microtensile bond strength.

  8. Species type controls root strength and influences slope stability in coastal Ecuador

    Science.gov (United States)

    Anttila, E.; Wray, M. E.; Knappe, E.; Ogasawara, T.; Tholt, A.; Cliffe, B.; Oshun, J.

    2014-12-01

    Tree roots, particular those of old growth trees, provide significant cohesive strength that can prevent shallow landslides. Little is known about the root strength of trees growing in dry tropical forests. In 1997, Bahía de Caráquez, Ecuador experienced a large landslide, which may have been precipitated by massive deforestation along the Ecuadorian coast. We used a tensile spring apparatus combined with root maps to caclulate the cohesive strength of different native species of trees. Whereas the results show the previously reported power law relationship between root diameter and tensile strength, our data also reveals new contributions. First, we find that trees have far stronger and more abundant roots than neighboring bushes, and thus add far more cohesive strength to the hillslope. Furthermore, there is a wide range of tensile strength among the native trees measured, with algarrobo having the strongest roots, and ceibo gernally being weak rooted. Finally, we use a slope stability model to predict failure conditions considering the strength added to a hillslope if vegetation is predominantly composed of bushes, algarrobo, or ceibo. Our results, which are the first of their kind for the Ecuadorian dry tropical forest, will be used to guide the ongoing native reforestation efforts of Global Student Embassy. Our unique partnership with Global Student Embassy connects our field study to practical land use decisions that will lead to increased slope and decreased human danger along coastal Ecuador's dry tropical forest.

  9. The influence of groundwater flow effect on changes of loess soil strength characteristics

    Directory of Open Access Journals (Sweden)

    Bida S.V.

    2015-09-01

    Full Text Available The problem of stability of slopes - one of the most topical at present. It is proved that the reliability of the slope stability assessment affects the accuracy of the strength characteristics of the soil. One of the most common methods is one-plane shifts method Established that processing of results of soil shift test in logarithmic coordinates can more accurately identify indicators of strength. Discovered that the magnitude of the strength characteristics of soil test results which is obtained on one plane shift depends on the vertical pressure during testing.

  10. Influence of diesel engine combustion on the rupture strength of partially stabilized zirconia

    International Nuclear Information System (INIS)

    Brinkman, C.R.; Begun, G.M.; Cavin, O.B.; Foster, B.E.; Graves, R.L.; Kahl, W.K.; Liu, K.C.; Simpson, W.A.

    1989-01-01

    Results are reported for tests on partially stabilized zirconia (PSZ-TS and MS grade) bars exposed in the combustion chambers of two operating single-cylinder 0.825-L diesel engines. Specifics of test conditions and procedures are presented. Subsequent to exposure, the bars were subjected to four-point bending and the rupture strengths determined. The TS grade showed a decrease in average strength of 32%, while the strength of the MS grade decreased by about 9% in comparison to average behavior of unaged material. Results of X-ray diffraction analysis, Raman spectroscopy, isothermal aging studies, and ceramographic characterization are given to define reasons for material degradation

  11. The Influences of Iron Ore Tailings as Fine Aggregate on the Strength of Ultra-High Performance Concrete

    Directory of Open Access Journals (Sweden)

    Zhigang Zhu

    2015-01-01

    Full Text Available The present study looks for the feasibility of preparing UHPC with iron ore tailings (IOT for short as fine aggregate. To enhance outstanding high performances, some influences on UHPC mortars were investigated such as different kinds of sands, different mix ratio of sands, and different largest particle size of fine aggregate. The results show that IOT have negligible poorer aggregate performance than silica sands but better than river sands. The strength of UHPC reaches the highest point when silica sands were instead 60% by IOT. As the largest particle size of fine aggregate is decreasing, the strength and frost resistance of UHPC were improved, but the liquidity was decreased. Micropowder of IOT affects the strength and the optimal content was 4%.

  12. Influence of surface treatment of yttria-stabilized tetragonal zirconia polycrystal with hot isostatic pressing on cyclic fatigue strength.

    Science.gov (United States)

    Iijima, Toshihiko; Homma, Shinya; Sekine, Hideshi; Sasaki, Hodaka; Yajima, Yasutomo; Yoshinari, Masao

    2013-01-01

    Hot isostatic pressing processed yttria-stabilized tetragonal zirconia polycrystal (HIP Y-TZP) has the potential for application to implants due to its high mechanical performance. The aim of this study was to investigate the influence of surface treatment of HIP Y-TZP on cyclic fatigue strength. HIP Y-TZP specimens were subjected to different surface treatments. Biaxial flexural strength was determined by both static and cyclic fatigue testing. In the cyclic fatigue test, the load was applied at a frequency of 10 Hz for 10(6) cycles in distilled water at 37°C. The surface morphology, roughness, and crystal phase of the surfaces were also evaluated. The cyclic fatigue strength (888 MPa) of HIP Y-TZP with sandblasting and acid-etching was more than twice that of Y-TZP as specified in ISO 13356 for surgical implants (320 MPa), indicating the clinical potential of this material.

  13. Experimental investigation of the factors influencing the polymer-polymer bond strength during two component injection moulding

    DEFF Research Database (Denmark)

    Islam, Mohammad Aminul; Hansen, Hans Nørgaard; Tang, Peter Torben

    2007-01-01

    Two component injection moulding is a commercially important manufacturing process and a key technology for Moulded Interconnect Devices (MIDs). Many fascinating applications of two component or multi component polymer parts are restricted due to the weak interfacial adhesion of the polymers...... effectively control the adhesion between two polymers. The effects of environmental conditions on the bond strength after moulding are also investigated. The material selections and environmental conditions were chosen based on the suitability of MID production, but the results and discussion presented....... A thorough understanding of the factors that influence the bond strength of polymers is necessary for multi component polymer processing. This paper investigates the effects of the process and material parameters on the bond strength of two component polymer parts and identifies the factors which can...

  14. Experimental investigation of the factors influencing the polymer-polymer bond strength during two-component injection moulding

    DEFF Research Database (Denmark)

    Islam, Aminul; Hansen, Hans Nørgaard; Bondo, Martin

    2010-01-01

    Two-component injection moulding is a commercially important manufacturing process and a key technology for combining different material properties in a single plastic product. It is also one of most industrially adaptive process chain for manufacturing so-called moulded interconnect devices (MIDs......). Many fascinating applications of two-component or multi-component polymer parts are restricted due to the weak interfacial adhesion of the polymers. A thorough understanding of the factors that influence the bond strength of polymers is necessary for multi-component polymer processing. This paper...... investigates the effects of the process conditions and geometrical factors on the bond strength of two-component polymer parts and identifies the factors which can effectively control the adhesion between two polymers. The effects of environmental conditions on the bond strength are also investigated...

  15. Influence of friction stir welding process and tool parameters on strength properties of AA7075-T6 aluminium alloy joints

    International Nuclear Information System (INIS)

    Rajakumar, S.; Muralidharan, C.; Balasubramanian, V.

    2011-01-01

    The aircraft aluminium alloys generally present low weldability by traditional fusion welding process. The development of the friction stir welding has provided an alternative improved way of satisfactorily producing aluminium joints, in a faster and reliable manner. In this present work, the influence of process and tool parameters on tensile strength properties of AA7075-T 6 joints produced by friction stir welding was analysed. Square butt joints were fabricated by varying process parameters and tool parameters. Strength properties of the joints were evaluated and correlated with the microstructure, microhardness of weld nugget. From this investigation it is found that the joint fabricated at a tool rotational speed of 1400 rpm, welding speed of 60 mm/min, axial force of 8 kN, using the tool with 15 mm shoulder diameter, 5 mm pin diameter, 45 HRc tool hardness yielded higher strength properties compared to other joints.

  16. Applying Strengths Model principles to build a rural community-based mental health support service and achieve recovery outcomes.

    Science.gov (United States)

    Dunstan, Debra; Anderson, Donnah

    2018-02-01

    The Personal Helpers and Mentors (PHaMs) service is a non-clinical, community-based Australian Government initiative aimed at increasing opportunities for recovery for people whose lives are severely affected by mental illness. Using a strengths-based recovery model, PHaMs caseworkers support and mentor people 'at risk of falling through the gaps' between state funded clinical treatment services and federally funded social services (such as supported housing, education and employment). While there is evidence that PHaMs realises its aim in metropolitan areas, little is known about how services are developed and function in low resource rural settings and what outcomes are achieved. These questions were addressed in a case study of a PHaMs service in a rural town in the state of New South Wales, Australia. Data were collected from two sources: local service documents prepared for staff orientation and operational purposes, and records and reports of service participants\\' performance and achievements. Participants\\' gains in wellbeing, recovery goals, and the target outcome areas of increased access to services, increased personal capacity and self-reliance, and increased community participation, were gathered from self-reports. The Role Functioning Scale was used as a measure of caseworker ratings of participants\\' adaptive functioning. The qualitative data were examined for semantic content and underlying themes. The quantitative analyses involved repeated measures and between-groups comparisons of uncontrolled pre-test–post-test and retrospective pre-test data. From commencement of the service in October 2009 to June 2014, an estimated 31% of the people living with severe mental illness in the local government area had accessed the PHaMs service (N=126; mean age 31.9 years; 42% male, 27% Aboriginal). The document analysis revealed that despite a lack of detail on how a PHaMs service should be developed or delivered, by focusing on the goal of client recovery

  17. Influence of gamma-radiation on tensile strength properties of polytetrafluoroethylene (PTFE)

    CERN Document Server

    Gafurov, U G; Nemkova, N

    2002-01-01

    The tensile strength properties of polytetrafluoroethylene are studied at modification doses of gamma-irradiation. The main molecular process of polymer destruction is found to be the thermostimulated slippage of molecular chains. (author)

  18. Influence of ultraviolet irradiation treatment on porcelain bond strength of titanium surfaces.

    Science.gov (United States)

    Kumasaka, Tomonari; Ohno, Akinori; Hori, Norio; Hoshi, Noriyuki; Maruo, Katsuichiro; Kuwabara, Atsushi; Seimiya, Kazuhide; Toyoda, Minoru; Kimoto, Katsuhiko

    2018-01-26

    To determine the effect of titanium (Ti) surface modification by ultraviolet irradiation (UVI) on the bond strength between Ti and porcelain. Grade 2 Ti plates were allotted to five groups: sandblasted (SA), 15 min UVI (UV), SA+5 min UVI (SA+UV5), SA+10 min UVI (SA+UV10), and SA+15 min UVI (SA+UV15). After surface treatment, porcelain was added. A precious metal (MC) was used for comparison with Ti. The effects of 24-h storage at room temperature versus thermal cycling only at 5 and 55°C in water were evaluated. Subsequently, the tensile strength of each sample was tested. Data were analyzed using one-way analysis of variance and the Tukey test. In both the room temperature and thermal cycling groups, the MC and SA+15 min UVI samples showed significantly greater bond strengths than the other samples (pbond strength between porcelain and the Ti surface.

  19. Survival and Injury Outcome After TBI: Influence of Pre- and Post-Exposure to Caffeine

    Science.gov (United States)

    2012-10-01

    10-1-0757 TITLE: Survival and Injury Outcome After TBI: Influence of Pre- and Post- Exposure to Caffeine PRINCIPAL INVESTIGATOR...Lusardi, Ph.D. Survival and Injury Outcome After TBI: Influence of Pre- and Post- Exposure to Caffeine 33 Legacy Emanual Hospital & Health Center...Phase 1: Study the prophylactic effects of caffeine exposure prior to FPI

  20. Manual and oral apraxia in acute stroke, frequency and influence on functional outcome

    DEFF Research Database (Denmark)

    Pedersen, P M; Jørgensen, H S; Kammersgaard, L P

    2001-01-01

    To determine the frequency of manual and oral apraxia in acute stroke and to examine the influence of these symptoms on functional outcome.......To determine the frequency of manual and oral apraxia in acute stroke and to examine the influence of these symptoms on functional outcome....

  1. The Influence of Wagon Structure Part Shape Optimization on Ultimate Fatigue Strength

    OpenAIRE

    Milovanović, Vladimir; Živković, Miroslav; Jovičić, Gordana; Živković, Jelena; Kozak, Dražan

    2016-01-01

    This study investigates how shape optimisation affects the ultimate fatigue strength of a mechanical part. The mechanical part chosen for this investigation is an axle guard of running gear elements of the Hccrrs 2x2 axle car-carrying wagon. The static and fatigue strength analysis procedure according to the UIC 517 standard and numerical methods have been applied. Material properties were determined experimentally and the necessary numerical calculations were performed by using the finite el...

  2. Influence of Eco-Friendly Mineral Additives on Early Age Compressive Strength and Temperature Development of High-Performance Concrete

    Science.gov (United States)

    Kaszynska, Maria; Skibicki, Szymon

    2017-12-01

    High-performance concrete (HPC) which contains increased amount of both higher grade cement and pozzolanic additives generates more hydration heat than the ordinary concrete. Prolonged periods of elevated temperature influence the rate of hydration process in result affecting the development of early-age strength and subsequent mechanical properties. The purpose of the presented research is to determine the relationship between the kinetics of the heat generation process and the compressive strength of early-age high performance concrete. All mixes were based on the Portland Cement CEM I 52.5 with between 7.5% to 15% of the cement mass replaced by the silica fume or metakaolin. Two characteristic for HPC water/binder ratios of w/b = 0.2 and w/b = 0.3 were chosen. A superplasticizer was used to maintain a 20-50 mm slump. Compressive strength was determined at 8h, 24h, 3, 7 and 28 days on 10x10x10 cm specimens that were cured in a calorimeter in a constant temperature of T = 20°C. The temperature inside the concrete was monitored continuously for 7 days. The study determined that the early-age strength (t<24h) of concrete with reactive mineral additives is lower than concrete without them. This is clearly visible for concretes with metakaolin which had the lowest compressive strength in early stages of hardening. The amount of the superplasticizer significantly influenced the early-age compressive strength of concrete. Concretes with additives reached the maximum temperature later than the concretes without them.

  3. Influence of Curing Humidity on the Compressive Strength of Gypsum-Cemented Similar Materials

    Directory of Open Access Journals (Sweden)

    Weiming Guan

    2016-01-01

    Full Text Available The analogous simulation experiment is widely used in geotechnical and mining engineering. However, systematic errors derived from unified standard curing procedure have been underestimated to some extent. In this study, 140 gypsum-cemented similar material specimens were chosen to study their curing procedure with different relative humidity, which is 10%–15%, 40%, 60%, and 80%, respectively. SEM microstructures and XRD spectra were adopted to detect the correlation between microstructures and macroscopic mechanical strength during curing. Our results indicated that the needle-like phases of similar materials began to develop in the early stage of the hydration process through intersecting with each other and eventually transformed into mat-like phases. Increase of humidity may inhibit the development of needle-like phases; thus the compressive strength changes more smoothly, and the time required for the material strength to reach the peak value will be prolonged. The peak strength decreases along with the increase of humidity while the humidity is higher than 40%; however, the reverse tendency was observed if the humidity was lower than 40%. Finally, we noticed that the material strength usually reaches the peak value when the water content continuously reduces and tends towards stability. Based on the above observation, a curing method determination model and experimental strength predication method for gypsum-cemented similar materials were proposed.

  4. Bond strength of three luting agents to zirconia ceramic - influence of surface treatment and thermocycling

    Directory of Open Access Journals (Sweden)

    Ahmed Attia

    2011-08-01

    Full Text Available OBJECTIVE: This in vitro study aimed to evaluate the influence of different surface treatments, 3 luting agents and thermocycling on microtensile bond strength (µTBS to zirconia ceramic. Material and METHODS: A total of 18 blocks (5x5x4 mm were fabricated from zirconia ceramic (ICE Zirkonia and duplicated into composite blocks (Alphadent. Ceramic blocks were divided into 3 groups (n=6 according to the following surface treatments: airborne-particle abrasion (AA, silica-coating, (SC (CoJet and silica coating followed by silane application (SCSI (ESPE Sil. Each group was divided into 3 subgroups (n=2 according to the 3 luting agents used. Resin-modified glass-ionomer cement (RMGIC, Ketac Cem Plus, self-adhesive resin cement (UN, RelyX Unicem and adhesive resin cement (ML, MultiLink Automix were used for bonding composite and zirconia blocks. Each bonding assembly was cut into microbars (10 mm long and 1±0.1 mm². Seven specimens of each subgroup were stored in water bath at 37ºC for 1 week. The other 7 specimens were stored in water bath at 37ºC for 30 days then thermocycled (TC for 7,500 cycles. µTBS values were recorded for each specimen using a universal testing machine. Statistical analyses were performed using a 3-way ANOVA model followed by serial 1-way ANOVAs. Comparison of means was performed with Tukey's HSD test at (α=0.05. RESULTS: µTBS ranged from 16.8 to 31.8 MPa after 1 week and from 7.3 to 16.4 MPa after 30 days of storage in water and thermocycling. Artificial aging significantly decreased µTBS (p<0.05. Considering surface treatment, SCSI significantly increased µTBS (p<0.05 compared to SC and AA. Resin cements (UN and ML demonstrated significantly higher µTBS (p<0.05 compared to RMGIC cement. CONCLUSIONS: Silica coating followed by silane application together with adhesive resin cements significantly increased µTBS, while thermocycling significantly decreased µTBS.

  5. Influence of Temporary Cements on the Bond Strength of Self-Adhesive Cement to the Metal Coronal Substrate.

    Science.gov (United States)

    Peixoto, Raniel Fernandes; De Aguiar, Caio Rocha; Jacob, Eduardo Santana; Macedo, Ana Paula; De Mattos, Maria da Gloria Chiarello; Antunes, Rossana Pereira de Almeida

    2015-01-01

    This research evaluated the influence of temporary cements (eugenol-containing [EC] or eugenol-free [EF]) on the tensile strength of Ni-Cr copings fixed with self-adhesive resin cement to the metal coronal substrate. Thirty-six temporary crowns were divided into 4 groups (n=9) according to the temporary cements: Provy, Dentsply (eugenol-containing), Temp Cem, Vigodent (eugenol-containing), RelyX Temp NE, 3M ESPE (eugenol-free) and Temp Bond NE, Kerr Corp (eugenol-free). After 24 h of temporary cementation, tensile strength tests were performed in a universal testing machine at a crosshead speed of 0.5 mm/min and 1 kN (100 kgf) load cell. Afterwards, the cast metal cores were cleaned by scraping with curettes and air jet. Thirty-six Ni-Cr copings were cemented to the cast metal cores with self-adhesive resin cement (RelyX U200, 3M ESPE). Tensile strength tests were performed again. In the temporary cementation, Temp Bond NE (12.91 ± 2.54) and Temp Cem (12.22 ± 2.96) presented the highest values of tensile strength and were statistically similar to each other (p>0.05). Statistically significant difference (pcementation of Ni-Cr copings with self-adhesive resin cement. In addition, Temp Cem (120.68 ± 48.27) and RelyX Temp NE (103.04 ± 26.09) showed intermediate tensile strength values. In conclusion, the Provy eugenol-containing temporary cement was associated with the highest bond strength among the resin cements when Ni-Cr copings were cemented to cast metal cores. However, the eugenol cannot be considered a determining factor in increased bond strength, since the other tested cements (1 eugenol-containing and 2 eugenol-free) were similar.

  6. Influence of brazing conditions on the strength of brazed joints of alumina dispersion-strengthened copper to 316 stainless steel

    International Nuclear Information System (INIS)

    Nishi, H.; Kikuchi, K.

    1998-01-01

    Brazing of alumina dispersion-strengthened copper (DS Cu) to 316 stainless steel were conducted in order to investigate the influence of filler metals and brazing conditions on the joint strength. The brazing were performed with a silver-base (BAg-8) and three kinds of gold-base (BAu-2.4.11) filler metals with varying brazing joint clearance and brazing time. The filler metal had a greater effect on the joint strength than the brazing joint clearance and brazing time. The joint with BAu-2 was superior to the joint with other filler metals. The tensile strength of the joint with BAu-2 was as large as that of DS Cu, however, the Charpy and low cycle fatigue strength were lower than those of DS Cu. The DS Cu melted near the brazed zone, consequently recrystallization and agglomeration of alumina occurred in the diffusion layer for all filler metals. The grain size after the recrystallization was small in order of BAu-2. BAu-4 and BAu-11, that was in accordance with the order of the brazing temperature. The excellent fracture strength for the joint with BAu-2 was attributed to the smallest grain size. (orig.)

  7. Influence of tool geometry and process parameters on macrostructure and static strength in friction stir spot welded polyethylene sheets

    International Nuclear Information System (INIS)

    Bilici, Mustafa Kemal; Yuekler, Ahmet Irfan

    2012-01-01

    Highlights: → All velding parameters and different tool geometries have demonstrated a different effects on weld strength. → Friction stir spot welding of polyethylene mechanical scission is very important. → Metric screw the tool has a great influence on the weld strength of FSSW. -- Abstract: The effect of important welding parameters and tool properties that are effective on static strength in friction stir spot welds of polyethylene sheets were studied. Six different tool pin profiles (straight cylindrical, tapered cylindrical, threaded cylindrical, triangular, square and hexagonal) with different shoulder geometries, different pin length, pin angle and concavity angle were used to fabricate the joints. The tool rotational speed, tool plunge depth and dwell time were determined welding parameters. All the welding operations were done at the room temperature. Welding force and welding zone material temperature measurements were also done. Lap-shear tests were carried out to find the weld static strength. Weld cross section appearance observations were also done. From the experiments, the effect of pin profile, pin length, pin angle, dwell time and tool rotational speed on friction stir spot welding formation and weld strength was determined.

  8. The Gait Deviation Index Is Associated with Hip Muscle Strength and Patient-Reported Outcome in Patients with Severe Hip Osteoarthritis

    DEFF Research Database (Denmark)

    Rosenlund, Signe; Holsgaard-Larsen, Anders; Overgaard, Søren

    2016-01-01

    ) and with severe primary hip osteoarthritis underwent 3-dimensional gait analysis. Mean Gait Deviation Index, pain after walking and maximal isometric hip muscle strength (flexor, extensor, and abductor) were recorded. All patients completed the 'Physical Function Short-form of the Hip disability...... was to investigate associations between Gait Deviation Index as a measure of gait 'quality' and hip muscle strength and between Gait Deviation Index and patient-reported outcomes in patients with primary hip osteoarthritis. METHOD: Forty-seven patients (34 males), aged 61.1 ± 6.7 years, with BMI 27.3 ± 3.4 (kg/m2...... and Osteoarthritis Outcome Score (HOOS-Physical Function) and the Hip disability and Osteoarthritis Outcome Score subscales for pain (HOOS-Pain) and quality-of-life (HOOS-QOL). RESULTS: Mean Gait Deviation Index was positively associated with hip abduction strength (pstrength (p = 0...

  9. Influence of Fracture Width on Sealability in High-Strength and Ultra-Low-Permeability Concrete in Seawater

    OpenAIRE

    Fukuda, Daisuke; Nara, Yoshitaka; Hayashi, Daisuke; Ogawa, Hideo; Kaneko, Katsuhiko

    2013-01-01

    For cementitious composites and materials, the sealing of fractures can occur in water by the precipitation of calcium compounds. In this study, the sealing behavior in a macro-fractured high-strength and ultra-low-permeability concrete (HSULPC) specimen was investigated in simulated seawater using micro-focus X-ray computed tomography (CT). In particular, the influence of fracture width (0.10 and 0.25 mm) on fracture sealing was investigated. Precipitation occurred mainly at the outermost pa...

  10. Influence of matrix metalloproteinase synthetic inhibitors on dentin microtensile bond strength of resin cements.

    Science.gov (United States)

    Stape, T H S; Menezes, M S; Barreto, B C F; Aguiar, F H B; Martins, L R; Quagliatto, P S

    2012-01-01

    This study evaluated the effect of dentin pretreatment with 2% chlorhexidine (CHX) or 24% ethylenediamine tetra-acetic acid gel (EDTA) on the dentin microtensile bond strength (μTBS) of resin cements. Composite blocks were luted to superficial noncarious human dentin (n=10) using two resin cements (RelyX ARC [ARC] and RelyX U100 [U100]) and three dentin pretreatments (without pretreatment-control, CHX, and EDTA). CHX was applied for 60 seconds on the acid-etched dentin in the ARC/CHX group, and for the same time on smear layer-covered dentin in the U100/CHX group. EDTA was applied for 45 seconds on smear-covered dentin in the U100/EDTA group, and it replaced phosphoric acid conditioning in the ARC/EDTA group for 60 seconds. After storage in water for 24 hours, specimens were prepared for microtensile bond strength testing. The results were submitted to two-way analysis of variance (ANOVA) followed by Tukey test. ARC produced significantly higher μTBS (pEDTA was used. For ARC, no pretreatment and CHX produced higher μTBS than EDTA. For U100, EDTA produced higher μTBS; no statistical difference occurred between CHX pretreatment and when no pretreatment was performed. While CHX did not affect immediate dentin bond strength of both cements, EDTA improved bond strength of U100, but it reduced dentin bond strength of ARC.

  11. Influence of heat treatment on the strength and fracture toughness of 7N01 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bo [School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan (China); Wang, Xiaomin, E-mail: xmwang991011@163.com [School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan (China); Chen, Hui; Hu, Jie [School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan (China); Huang, Cui [School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan (China); Gou, Guoqing [School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan (China)

    2016-09-05

    7N01 aluminum (Al) alloys are treated by five heat treatment methods as peak aging (T6), over aging (T74), high temperature and subsequently low temperature aging (HLA), retrogression and reaging (RRA) and double retrogression and reaging (DRRA). The strength and fracture toughness of the five samples are tested, and the microstructures are investigated by optical microscopy (OM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The results show that 7N01 Al-alloy treated at T6 condition has high strength but low fracture toughness. Compared with T6 treatment, T74 and HLA treatments increase the fracture toughness by 67% and 90% respectively, while the strength decrease by 9% and 17%. RRA process is a proper treatment method for 7N01 which improves the fracture toughness without sacrificing strength. The fracture toughness of DRRA treated alloy is much lower than that of RRA. Quantitative analysis through TEM images shows that the heat treatment affects the mechanical properties of 7N01 Al-alloy highly through changing the precipitates in grains and on grain boundaries, which can be explained by the coherency strengthening mechanism and Orowan mechanism. - Highlights: • Five heat treatments which can change the properties of 7N01 Al alloy were designed. • Quantitative analysis of precipitates was employed to study the mechanism. • RRA treatment can make proper strength/toughness property balances for 7N01 Al alloy.

  12. Influence of Curing Conditions on Long-Term Compressive Strength of Mortars with Accelerating Admixtures

    Science.gov (United States)

    Pizoń, Jan; Łaźniewska-Piekarczyk, Beata

    2017-10-01

    One of disadvantages of accelerating admixtures usage is possibility of significant decline of long-term compressive strength of concrete in comparison to non-modified one. Described tests were intended to define scale of lowered long-term compressive strength of mortars caused by accelerating admixtures in different curing conditions. Portland cement and blended cement with ground granulated blast furnace slag (GGBFS) addition and four types of non-chloride accelerating agents were used. Compressive strength was tested after 7 up to 360 days. Curing conditions were designed to simulate probable conditions close to reality. Such conditions are simulation of internal concrete elements, external elements cast on start of summer and external elements cast on start of winter. Results had shown that it is invalid to state that every accelerating admixture will cause drop of long-term compressive strength in every conditions and for every cement type. Change of curing conditions even after a long time (in this case half of the year) leads to significant differences in compression strength.

  13. Influence of surface treatments on the shear bond strength of orthodontic brackets to porcelain

    Science.gov (United States)

    Wang, Cong; Zeng, Jishan; Wang, Shaoan; Yang, Zheng; Huang, Qian; Chen, Pixiu; Zhou, Shujuan; Liu, Xiaoqing

    2008-11-01

    The purpose of this study was to investigate the effect of various surface treatments after different storage time and thermocycling on the shear bond strength of orthodontic brackets to the feldspathic porcelain surfaces. 128 disc-shaped porcelain specimens were randomly assigned to the following surface treatments: 9.6% HFA, 9.6% HFA combined with silane, 50 μ aluminum trioxide sandblasting followed by silane and application of silane after 37% phosphoric acid. Metal or ceramic brackets were bonded onto each treated porcelain facet with light cured resin. The samples were stored in 37 °C water 1 day or 7 days, thermocycled 500 times from 5 to 55 °C. The shear bond strengths were measured (1 mm/min), and statistically analyzed. The bond failure sites were classified according to ARI system. The surface of the glazed, sandblasted, hydrofluoric and phosphoric acid etched porcelain were examined with SEM. All groups achieved reasonable bond strengths to withstand the application of orthodontic forces. Water storage for 7 days caused lower shear bond strength than that of 1 day. But there is no statistically significant difference between the two groups. The mean shear bond strength provided by ceramic bracket with mechanical retention had no statistical difference with that of metal bracket. Therefore, the optimal treatment for orthodontic brackets bonding to feldspathic porcelain was to apply phosphoric acid combined with silane.

  14. Influence of previous acid etching on bond strength of universal adhesives to enamel and dentin.

    Science.gov (United States)

    Torres, Carlos Rocha Gomes; Zanatta, Rayssa Ferreira; Silva, Tatiane Josefa; Huhtala, Maria Filomena Rocha Lima; Borges, Alessandra Bühler

    2017-01-01

    The objective of this study was to evaluate the effect of acid pretreatment on the bond strength of composite resin bonded to enamel and dentin with 2 different universal self-etching adhesives. The null hypothesis was that the acid treatment performed prior to adhesive application would not significantly change the bond strength to enamel or dentin for either universal adhesive tested. A sample of 112 bovine incisors were selected and embedded in acrylic resin. Half were ground until a flat enamel surface was obtained, and the other half were polished until a 6 × 6-mm area of dentin was exposed, resulting into 2 groups (n = 56). The enamel and dentin groups were divided into 2 subgroups according to the adhesive system applied: Futurabond U or Scotchbond Universal. Each of these subgroups was divided into 2 additional subgroups (n = 14); 1 subgroup received phosphoric acid pretreatment, and 1 subgroup did not. The bond strength was assessed with a microtensile test. Data from enamel and dentin specimens were analyzed separately using 1-way analysis of variance. The acid pretreatment did not significantly change the bond strength of the adhesives tested, either to enamel (P = 0.4161) or to dentin (P = 0.4857). The acid etching pretreatment did not affect the bond strength to dentin and enamel when the tested universal multipurpose adhesive systems were used.

  15. Influence of heat treatment on the strength and fracture toughness of 7N01 aluminum alloy

    International Nuclear Information System (INIS)

    Li, Bo; Wang, Xiaomin; Chen, Hui; Hu, Jie; Huang, Cui; Gou, Guoqing

    2016-01-01

    7N01 aluminum (Al) alloys are treated by five heat treatment methods as peak aging (T6), over aging (T74), high temperature and subsequently low temperature aging (HLA), retrogression and reaging (RRA) and double retrogression and reaging (DRRA). The strength and fracture toughness of the five samples are tested, and the microstructures are investigated by optical microscopy (OM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The results show that 7N01 Al-alloy treated at T6 condition has high strength but low fracture toughness. Compared with T6 treatment, T74 and HLA treatments increase the fracture toughness by 67% and 90% respectively, while the strength decrease by 9% and 17%. RRA process is a proper treatment method for 7N01 which improves the fracture toughness without sacrificing strength. The fracture toughness of DRRA treated alloy is much lower than that of RRA. Quantitative analysis through TEM images shows that the heat treatment affects the mechanical properties of 7N01 Al-alloy highly through changing the precipitates in grains and on grain boundaries, which can be explained by the coherency strengthening mechanism and Orowan mechanism. - Highlights: • Five heat treatments which can change the properties of 7N01 Al alloy were designed. • Quantitative analysis of precipitates was employed to study the mechanism. • RRA treatment can make proper strength/toughness property balances for 7N01 Al alloy.

  16. How the Subpolar gyre strength influences phytoplankton blooms dynamics in the North Atlantic

    DEFF Research Database (Denmark)

    Ferreira, Ana Sofia; Payne, Mark; MacKenzie, Brian

    2012-01-01

    height (SSH, from the AVISO project) as a proxy of current strength. Three regions were strategically chosen to characterize positions relative to the NASPG, describing: region 1—the northern part of NASPG, including the Irminger Current (IC); region 2—the North Atlantic Current (NAC), its northwards......Changes in the North Atlantic Subpolar gyre (NASPG) have been linked to the interannual variability of primary production. However, little is known about the mechanisms behind both environmental processes, and how the NASPG strength may extend its potential impacts to higher trophic levels......, including early life stages of commercial fish species. We assess NASPG strength effect on North Atlantic phytoplankton bloom dynamics. We analyse time‐series (from 1998 to 2010) of chlorophyll a (Chl a, from the Globcolour project) annual anomaly as a proxy of phytoplankton abundance, and of sea surface...

  17. Infliximab's influence on anastomotic strength and degree of inflammation in intestinal surgery in a rabbit model

    DEFF Research Database (Denmark)

    Frostberg, Erik; Ström, Petter; Gerke, Oke

    2014-01-01

    and conclusions. The purpose of this study was to investigate whether a single dose infliximab has an adverse effect on the anastomotic healing process, observed as reduced anastomotic breaking strength and histopathologically verified lower grade of inflammatory response, in the small intestine of a rabbit....... METHODS: Thirty New Zealand rabbits (median weight 2.5 kg) were allocated to treatment with an intravenous bolus of either 10 mg/kg infliximab (n = 15) or placebo (n = 15). One week later all rabbits underwent two separate end-to-end anastomoses in the jejunum under general anesthesia. At postoperative...... day three, the anastomotic breaking strength was determined and histopathological changes were examined. RESULTS: The mean value of anastomotic breaking strength in the placebo group was 1.89 +/- 0.36 N and the corresponding value was 1.81 +/- 0.33 N in the infliximab treated rabbits...

  18. Influence of Nanolime and Curing Period on Unconfined Compressive Strength of Soil

    Directory of Open Access Journals (Sweden)

    Panbarasi Govindasamy

    2017-01-01

    Full Text Available This paper presents the improvement of the unconfined compressive strength (UCS of soil by mixing different percentages of nanolime and 5% lime with soil. The UCS of treated soil increased significantly over curing time with increasing percentage of nanolime. The optimum results were reached at only 0.5% nanolime admixtures which were much higher than 5% lime admixture. This may be due to higher ability of nanolime to flocculate and agglomerate the soil particles compared with the lime. In addition, the lime could fill only the micropores while nanolime could fill the micro- and nanopores as well. The strength gain is inversely proportional to the remolded moisture content and curing period. However, when the content of nanolime used is larger than 0.5%, nanolime particles are not uniformly dispersed. Therefore, a weak area in the form of voids is created, consequently the homogeneous hydrated microstructure cannot be formed, and finally the strength will decrease.

  19. Influence of the modes of laser cladding on bond strength and wear resistance of coatings

    Science.gov (United States)

    Birukov, V. P.; Tatarkin, D. Yu; Chriptovish, E. V.; Fichkov, A. A.

    2017-12-01

    The paper presents the results of metallographic studies and laboratory comparative tests on the adhesion strength of the coating to the substrate and abrasion on the scheme Brinell-Haworth cladding powder coatings on Nickel-based and samples of steel 40X. Strength of adhesion of the first coating layer with a hardness of HRC 38-42 was 400-480 MPa. It is shown that when the hardness of the deposited layer HRC 58-61 wear resistance of the coatings is higher than 40X steel in the normalized and improved in 10 and 4.6 times, respectively.

  20. Influence of superconductor film composition on adhesion strength of coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Kesgin, Ibrahim; Khatri, Narayan; Liu, Yuhao; Delgado, Louis; Galstyan, Eduard; Selvamanickam, Venkat

    2015-11-20

    The effect of high temperature superconductor (HTS) film composition on the adhesion strength of rare- earth barium copper oxide coated conductors (CCs) has been studied. It has been found that the mechanical integrity of the superconductor layer is very susceptible to the defects especially those along the ab plane, probably due to the weak interfaces between the defects and the matrix. Gd and Y in the standard composition were substituted with Sm and the number of in-plane defects was drastically reduced. Consequently, a four-fold increase in adhesion or peeling strength in Sm-based CCs was achieved compared to the standard GdYBCO samples.

  1. Influence of superconductor film composition on adhesion strength of coated conductors

    International Nuclear Information System (INIS)

    Kesgin, Ibrahim; Khatri, Narayan; Liu, Yuhao; Delgado, Louis; Galstyan, Eduard; Selvamanickam, Venkat

    2016-01-01

    The effect of high temperature superconductor (HTS) film composition on the adhesion strength of rare-earth barium copper oxide coated conductors (CCs) has been studied. It has been found that the mechanical integrity of the superconductor layer is very susceptible to the defects especially those along the ab plane, probably due to the weak interfaces between the defects and the matrix. Gd and Y in the standard composition were substituted with Sm and the number of in-plane defects was drastically reduced. Consequently, a four-fold increase in adhesion or peeling strength in Sm-based CCs was achieved compared to the standard GdYBCO samples. (paper)

  2. The influence of cellular structures on flow stress of high strength components manufactured using SLM

    DEFF Research Database (Denmark)

    Mahshid, Rasoul; Hansen, Hans Nørgaard; Loft Højbjerre, Klaus

    2016-01-01

    Additive manufacturing has shown significant improvement in material and machines for high-quality solid freeform fabrication processes such as selective laser melting (SLM). In particular, manufacturing lattice structures using the SLM procedure is of interest. This research examines the effect...... of cellular materials on compression strength. The specimens are manufactured additively using industrial 3D printing systems from high-strength alloy. The material has the right mechanical properties for manufacturing tool components. This includes samples with solid and lattice structures. The Compression...

  3. The influence of humidity on strengths and durability of light guides fibers

    International Nuclear Information System (INIS)

    Karimov, S.N.; Kuksenko, V.S.; Sultonov, U.; Abdumanonov, A.; Shamsidinov, M.I.

    1993-01-01

    Humidity influence on durability and light water durability fibres is studied are studied in this article. Humidity energy under influence of process destruction decreases activity, durability and durability decreases is shown

  4. A comprehensive study on the influence of strength and stiffness eccentricities to the on-plan rotation of asymmetric structure

    Science.gov (United States)

    Rashidi, Azida; Majid, Taksiah A.; Fadzli, M. N.; Faisal, Ade; Noor, Suhaila M.

    2017-10-01

    All buildings are subjected to some degree of torsion which in turn changes the member torsional demands from that of translation only. Torsional effects on buildings subjected to earthquakes are not found directly in structural analysis unless full three-dimensional inelastic dynamic time history analysis is conducted. Since design is often conducted using two-dimensional analysis, these effects are not directly considered. There is currently an understanding on how different factors may influence torsion, however, the degree to which these factors influence torsion is relatively unknown. Slab rotation effect is considered a major response parameter to represent the severity of the torsional response of eccentric systems; hence, it is considered in this study. The centre of strength (CR) and centre of stiffness (CS) are the two main factors under considerations. A comprehensive analysis on eighty different CR and CS conditions are applied to a three-dimensional, asymmetric building and their influences to slab rotation are observed. The CR/CS conditions are applied by varying strength eccentricities (er) and stiffness eccentricities (es) using two condition models. Then, earthquake ground motions are applied in z-direction under elastic and inelastic conditions. The results interpreted using a simple approach shows important slab rotation behaviour that forms interesting findings from this study. The slab rotation demand is found to reduce as strength eccentricity moves away from the Centre of Mass (CoM) but is independent of the stiffness eccentricity. The study also confirms finding of previous works which states that stiffness eccentricity plays a minor role when assessing the torsional behaviour of a ductile systems. Results from inelastic analysis shows slab rotation demand increases as strength eccentricity is closer to the CoM but it remains constant for elastic analysis.

  5. Influence of frequency and duration of strength training for effective management of neck and shoulder pain

    DEFF Research Database (Denmark)

    Andersen, Christoffer H; Andersen, Lars Louis; Gram, Bibi

    2012-01-01

    training (REF). Primary outcome was self-reported neck and shoulder pain (scale 0-9) and secondary outcome work disability (Disability in Arms, Shoulders and Hands (DASH)). RESULTS: The intention-to-treat analysis showed reduced neck and right shoulder pain in the training groups after 20 weeks compared...

  6. Influence of synthetic calcium silicates on the strength properties of fine-grained concrete

    Science.gov (United States)

    Yarusova, S. B.; Gordienko, P. S.; Kozin, A. V.; Zhevtun, I. G.; Perfilev, A. V.

    2018-04-01

    The effect of additives based on acicular calcium hydrosilicates (xonotlite and tobermorite) and wollastonite, obtained from boric acid production waste in autoclave synthesis at a temperature of 220 °C, on the strength of fine-grained concrete, has been studied in this paper. It was shown that when the calcium hydrosilicates and wollastonite are introduced, an increase in the strength characteristics of concrete is observed. After heat and moisture treatment, the maximum increase in strength is observed with the addition of 4% of mass content of calcium hydrosilicates and 6% of mass content of wollastonite. After 28 days of hardening under normal conditions, the maximum increase in strength of concrete is observed with the addition of 4% of mass content of both types of additives. It was shown that the water absorption of concrete decreases with a maximum when 4% of mass content is added, as in the case of the introduction of calcium hydrosilicates, and wollastonite. With a further increase in the number of additives, the amount of water absorption increases, but these values remain below the values for the control sample without additives.

  7. Influence of Internal Sulfate Attack on Some Properties of High Strength Concrete

    Directory of Open Access Journals (Sweden)

    Nada Mahdi Fawzi

    2015-08-01

    Full Text Available One of the most important problems that faces the concrete industry in Iraq is the deterioration due to internal sulfate attack , since it reduces the compressive strength and increases the expansion of concrete. Consequently, the concrete structure may be damage .The effects of total and total effective sulfate contents on high strength concrete (HSC have been studied in the present study. The research studied the effect of sulfate content in cement , sand and gravel , as well as comparing the total sulfate content with the total effective SO3 content. Materials used were divided into two groups of SO3 in cement ,three groups of SO3 in sand ,and two groups of SO3 in gravel. The results show that considering the total effective sulfate content is better than the total content of sulfates since the effect of sulfate in each constituent of concrete, depends on it's granular size .The smaller the particle size of the material the more effective is the sulfate in it. Therefore, it is recommended to follow the Iraqi specification for total effective sulfate content, because it gives more flexibility to the use of sand and gravel with higher sulfate content. The results of compressive strength at 90-days show that the effect of total effective SO3 content of ( 2.647% , 2.992% , 3.424% that correspond to total sulfate of ( 3.778%, 3.294%, 4.528% decrease the compressive strength by (7.53%, 11.44%, 14.59% respectively.

  8. Various conditioning methods for root canals influencing the tensile strength of titanium posts

    NARCIS (Netherlands)

    Schmage, P.; Sohn, J.; Nergiz, I.; Ozcan, M.; Nergiz, [No Value

    2004-01-01

    Conditioning the root canal is frequently advised to achieve high post-retention when resin composite luting cements are used. However, Manufacturers’ instructions for this purpose differ widely from one another. The aim of this study was to compare the tensile bond strengths of passive, tapered,

  9. The influence of water flow (reversal) on bond strength development in young masonry

    NARCIS (Netherlands)

    Groot, C.; Larbi, J.

    1999-01-01

    Water loss from the fresh mortar is believed to be related to mortar-brick bond strength development in masonry. Recent research on mortar-brick bond has shown that, particularly, effects of water flow on the composition and the hydration conditions of the mortar-brick interface have to be taken

  10. influence of orientation and size of voids on concrete cube strength

    African Journals Online (AJOL)

    Dr Obe

    (1982),"Structural Masonry Designer's. Manual", Granada Publishing Frogmore,. G.B.. 9. Ezeokonkwo, J.C (1988), "Uniaxial. Compressive Strength of Sandcrete. Hollow Blocks and its Dependence on. Geometry", M. Eng. Thesis, submitted to the Department of Civil Engineering,. University of Nigeria, Nsukka, Nigeria. 10.

  11. The influence of titanium dioxide additive on the short-term DC breakdown strength of polyethylene

    DEFF Research Database (Denmark)

    Khalil, M. S; Henk, Peter O; Henriksen, Mogens

    1990-01-01

    , with hemispherically tipped cylindrical electrodes completely embedded in the material, with a minimum gap length between the electrode tips of 0.25 mm. All tests were conducted at room temperature. Results indicate that, although the addition of TiO2 reduces the DC breakdown strength of the doped material if compared...

  12. Influence of EDC on Dentin-Resin Shear Bond Strength and Demineralized Dentin Thermal Properties

    Directory of Open Access Journals (Sweden)

    Lin Tang

    2016-11-01

    Full Text Available This study aimed to evaluate the bonding strength and thermal properties of demineralized dentin with and without EDC treatment. Sound human molars were randomly divided into seven treatment groups (n = 20: control, 80% ethanol, and five EDC ethanol solutions (0.01–1.0 M. In each group, 16 samples were used for bond strength assessment and 4 samples were used for scanning electron microscopy (SEM analysis. A further 70 intact molars were used to obtain a fine demineralized dentin powder, treated with the same solutions and were evaluated the crosslink degree by ninhydrin test and denaturation temperature (Td by differential scanning calorimetry. EDC-treated specimens (<1.0 M had a higher bond strength, especially 0.3 and 0.5 M group, than the control counterpart. There was a significant drop in bond strength of 1.0 M EDC group. SEM revealed a homogeneous and regular interface under all treatments. EDC treatment significantly increased the demineralized dentin cross-link degree and Td compared with the control and ethanol treatments. The 0.3 and 0.5 M treatments showed the highest cross-link degree and Td. In terms of mechnical and theramal properties consideration, 0.3 and 0.5 M EDC solutions may be favorable for when applied with etch-and-rinse adhesives, but it is still needed further long-term study.

  13. Influence of dentinal regions on bond strengths of different adhesive systems.

    Science.gov (United States)

    Ozer, F; Unlü, N; Sengun, A

    2003-06-01

    This in vitro study assessed comparatively the shear bond strengths of three composite resins, 3M Valux Plus (3MVP), Herculite (H), Clearfil AP-X (CAP-X), a polyacid modified composite resin Dyract (D), and a resin modified glass-ionomer materials Vitremer (V), to cervical and buccal dentine regions of extracted human molar teeth. Four different bonding systems, 3M ScotchBond Multipurpose (SB), Clearfil Liner Bond 2 (LB2), Opti Bond (OB), and Prime & Bond 2.1 (PB 2.1) were used with the manufacturer's respective composite and compomer materials. One hundred freshly extracted mandibular molar teeth were selected for this study. Flat buccal dentine surfaces were created on 50 teeth and cylindrical rods of the five materials were bonded to the dentine surfaces. For assessment of cervical bond strengths, the materials were bonded to mesial and distal enamel bordered occlusal dentinal surfaces of the remaining 50 teeth. The five groups of restorative procedures were applied as follows; Group 1: SB + 3MVP, Group 2: LB2 + CAP-X, Group 3: OB + H, Group 4: PB2.1 + D, Group 5: Vitremer primer (VP) VP + V. Each restorative procedure thus had 20 specimens (10 buccal + 10 cervical). After 24 h of water storage (37 degrees C), the specimens were tested on a Universal Testing machine in shear with a cross head speed of 0.5 mm min-1. The bond strength values were calculated in MPa and the results were evaluated statistically using Kruskal-Wallis one-way/anova and Mann-Whitney U-tests. It was found that the bond strengths of SB + 3MVP, LB2 + CAP-X and VP + V to buccal dentine surfaces were significantly stronger (P 0.05). Vitremer was found the least successful adhesive material in terms of shear bond strength on both buccal and occluso-cervical dentine surfaces.

  14. Investigating the impact of a combined approach of perceived organisational support for strengths use and deficit correction on employee outcomes

    NARCIS (Netherlands)

    Els, C.; Mostert, K.; van Woerkom, M.

    2018-01-01

    Orientation: The positive psychology paradigm suggests a balanced focus on employee strengths and deficits. However, an overemphasis on strengths has raised questions regarding the value of a focus on strengths use, deficit improvement or a combined approach with a balanced focus on both. Research

  15. Factors Influencing Visual Outcome after Surgery for Retinal ...

    African Journals Online (AJOL)

    Dr femi Oderinlo

    Three factors favourably affected visual outcome and were of statistical ... These changes are likely to affect the. 10,11 ... within the South Western geopolitical region of Nigeria is one of the ... tamponade (silicon oil or C F gas in a single case), or a combination ..... studies also had similar final anatomic success rates, 90.2%.

  16. Family and Community Influences on Educational Outcomes among Appalachian Youth

    Science.gov (United States)

    Brown, Ryan; Copeland, William E.; Costello, E. Jane; Erkanli, Alaattin; Worthman, Carol M.

    2009-01-01

    Recent research has shown how quantifiable aspects of community context affect a wide range of behaviors and outcomes. Due partially to the historical development of this field, currently published work focuses on urban rather than rural areas. We draw upon data from a longitudinal study of families and health in Appalachia--the Great Smoky…

  17. Influence of Welding Time on Tensile-Shear Strength of Linear Friction Welded Birch (Betula pendula L. Wood

    Directory of Open Access Journals (Sweden)

    Jussi Ruponen

    2015-04-01

    Full Text Available The purpose of this work was to determine the optimal welding time for linear friction welding of birch (Betula pendula L. wood while keeping the other parameters constant and at similar levels compared to other species in a similar density range. Specimens with dimensions of 20 × 5 × 150 mm3 were welded together, and the influence of welding time (2.5, 3.0, 3.5, and 4.0 s on the mechanical properties of the specimens was determined. The studies included a tensile-shear strength test as well as visual estimation of wood failure percentage (WFP. Additionally, X-ray microtomographic imaging was used to investigate and characterise the bond line properties as a non-destructive testing method. The highest mean tensile-shear strength, 7.9 MPa, was reached with a welding time of 3.5 s. Generally, all four result groups showed high, yet decreasing proportional standard deviations as the welding time increased. X-ray microtomographic images and analysis express the heterogeneity of the weld line clearly as well. According to the averaged group-wise results, WFP and tensile-shear strength correlated positively with an R2 of 0.93. An extrapolation of WFP to 65% totals a tensile-shear strength of 10.6 MPa, corresponding to four common adhesive bonds determined for beech.

  18. Influence of nanoparticles on color stability, microhardness, and flexural strength of acrylic resins specific for ocular prosthesis.

    Science.gov (United States)

    Andreotti, Agda Marobo; Goiato, Marcelo Coelho; Moreno, Amália; Nobrega, Adhara Smith; Pesqueira, Aldiéris Alves; dos Santos, Daniela Micheline

    2014-01-01

    The aim of this study was to assess the effect of adding nanoparticles to N1 acrylic resin intended for artificial sclera, in terms of the color stability, microhardness, and flexural strength of the resin. Three hundred samples of N1 acrylic resin were used: 100 samples for color stability and microhardness tests (each test was performed on the opposite side of each sample), and 200 samples for flexural strength testing (100 samples before and after 1,008 hours of accelerated aging). Samples for each test were separated into ten groups (n=10), ie, without nanoparticles (control group) or with nanoparticles of zinc oxide, titanium dioxide (TiO₂), and barium sulfate at weight concentrations of 1%, 2%, and 2.5% (nanoparticle groups). Data were subjected to statistical analysis with nested analysis of variance and Tukey's test (P<0.05 significance level). Among the nanoparticle groups, the TiO₂ groups showed better color stability at all concentrations. Microhardness values increased after artificial aging, except for the control and zinc oxide groups. After aging, the 1%-2% TiO₂ groups had significantly higher microhardness values compared with the other nanoparticle groups. Before aging, there was a significant difference in flexural strength between the control and nanoparticle groups. After aging, the control and TiO₂ groups, regardless of concentration, showed the lowest flexural strength values. Incorporation of nanoparticles directly influenced the acrylic resin properties, with TiO₂ being the most influential nanoparticle in terms of the evaluated properties.

  19. Influence of frequency on shear fatigue strength of resin composite to enamel bonds using self-etch adhesives.

    Science.gov (United States)

    Takamizawa, Toshiki; Scheidel, Donal D; Barkmeier, Wayne W; Erickson, Robert L; Tsujimoto, Akimasa; Latta, Mark A; Miyazaki, Masashi

    2016-09-01

    The purpose of this study was to determine the influence of different frequency rates on of bond durability of self-etch adhesives to enamel using shear fatigue strength (SFS) testing. A two-step self-etch adhesive (OX, OptiBond XTR), and two single step self-etch adhesives (GB, G-ӕnial Bond and SU, Scotchbond Universal) were used in this study. The shear fatigue strength (SFS) to enamel was obtained. A staircase method was used to determine the SFS values with 50,000 cycles or until failure occurred. Fatigue testing was performed at frequencies of 5Hz, 10Hz, and 20Hz. For each test condition, 30 specimens were prepared for the SFS testing. Regardless of the bond strength test method, OX showed significantly higher SFS values than the two single-step self-etch adhesives. For each of the three individual self-etch adhesives, there was no significant difference in SFS depending on the frequency rate, although 20Hz results tended to be higher. Regardless of the self-etch adhesive system, frequencies of 5Hz, 10Hz, and 20Hz produced similar results in fatigue strength of resin composite bonded to enamel using 50,000 cycles or until bond failure. Accelerated fatigue testing provides valuable information regarding the long term durability of resin composite to enamel bonding using self-etch adhesive system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Study populations and casemix: influence on analysis of postoperative outcomes.

    Science.gov (United States)

    Isbister, W H

    2000-04-01

    The importance of patient casemix as a determinant of surgical outcome is now being recognized. The present study was undertaken in order to compare the presentation and outcomes in colorectal patients managed surgically by the same surgeon, in the same way, in different settings. Colorectal outcome data from the University Department of Surgery in Wellington and the King Faisal Specialist Hospital in Riyadh were analysed in order to determine casemix differences between the two hospitals. Data relating to the type of surgery, the surgeon, the patient's disease, the operation performed and the postoperative complications were compared. Specific colorectal clinical indicators were compared for two commonly performed operations for rectal cancer: anterior resection and abdomino-perineal resection of the rectum. Wellington patients were slightly older and there were more females. Emergency surgery was more frequent in Wellington. Left hemicolectomy, sigmoid colectomy, abscess drainage and pilonidal surgery were more common in Wellington whereas abdomino-perineal resection and anterior resection of the rectum, stoma closure, fistula surgery, seton insertion, restorative proctocolectomy and ileostomy were undertaken more frequently in Riyadh. More complex anal fistulas were managed in Riyadh. Condylomata accuminata, pilonidal abscess, anorectal abscess, rectal prolapse and diverticular disease were rarely seen in Riyadh. There were more postoperative pulmonary and cardiac complications in Wellington. Patients having anterior resection of the rectum were younger in Riyadh and there were proportionally more females. There were some obvious numerical outcome differences in postoperative atelectasis, wound infection, anastomotic leak and deep vein thrombosis rates but none of these reached statistical significance except atelectasis. In Riyadh the usual male-to-female ratio of patients undergoing abdomino-perineal resection was reversed but, again, none of the numerical

  1. Neoadjuvant chemoradiotherapy of rectal carcinoma. Baseline hematologic parameters influencing outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Hodek, Miroslav; Sirak, Igor; Paluska, Petr; Kopecky, Jindrich; Petera, Jiri; Vosmik, Milan [University Hospital in Hradec Kralove, Department of Oncology and Radiotherapy, Hradec Kralove (Czech Republic); Ferko, Alexander; Oerhalmi, Julius [University Hospital in Hradec Kralove, Department of Surgery, Hradec Kralove (Czech Republic); Hovorkova, Eva; Hadzi Nikolov, Dimitar [University Hospital in Hradec Kralove, Fingerland Department of Pathology, Hradec Kralove (Czech Republic)

    2016-09-15

    The link between the blood count and a systemic inflammatory response (SIR) is indisputable and well described. Pretreatment hematological parameters may predict the overall clinical outcomes in many types of cancer. Thus, this study aims to systematically evaluate the relationship between baseline blood count levels and treatment response in rectal cancer patients treated with neoadjuvant chemoradiotherapy. From 2009-2015, 173 patients with locally advanced rectal cancer were retrospectively enrolled in the study and analyzed. The baseline blood count was recorded in all patients 1 week before chemoradiation. Tumor response was evaluated through pathologic findings. Blood count levels which included RBC (red blood cells), Hb (hemoglobin), PLT (platelet count), neutrophil count, WBC (white blood cells), NLR (neutrophil-to-lymphocyte ratio), and PLR (platelet-to-lymphocyte ratio) were analyzed in relation to tumor downstaging, pCR (pathologic complete response), OS (overall survival), and DFS (disease-free survival). Hb levels were associated with a response in logistic regression analysis: pCR (p = 0.05; OR 1.04, 95 % CI 1.00-1.07); T downstaging (p = 0.006; OR 1.03, 95 % CI 1.01-1.05); N downstaging (p = 0.09; OR 1.02, 95 % CI 1.00-1.04); T or N downstaging (p = 0.007; OR 1.04, 95 % CI 1.01-1.07); T and N downstaging (p = 0.02; OR 1.02, 95 % CI 1.00-1.04); Hb and RBC were the most significant parameters influencing OS; PLT was a negative prognostic factor for OS and DFS (p = 0.008 for OS); an NLR value of 2.8 was associated with the greatest significance for OS (p = 0.03) and primary tumor downstaging (p = 0.02). Knowledge of pretreatment hematological parameters appears to be an important prognostic factor in patients with rectal carcinoma. (orig.) [German] Die Verbindung zwischen dem Blutbild und der systemischen Entzuendungsreaktion (''systemic inflammatory response'', SIR) ist unbestreitbar und gut beschrieben. Aufgrund der

  2. Infliximab's influence on anastomotic strength and degree of inflammation in intestinal surgery in a rabbit model

    DEFF Research Database (Denmark)

    Frostberg, Erik; Ström, Petter; Gerke, Oke

    2014-01-01

    and conclusions. The purpose of this study was to investigate whether a single dose infliximab has an adverse effect on the anastomotic healing process, observed as reduced anastomotic breaking strength and histopathologically verified lower grade of inflammatory response, in the small intestine of a rabbit......BACKGROUND: Infliximab, a TNF-alpha inhibitor, is a potent anti-inflammatory drug in the treatment of inflammatory bowel diseases. Recent studies have investigated the effect of infliximab treatment on postoperative complications such as anastomotic leakage, however, with conflicting results...... of infliximab, given one week prior to surgery, does not have an impact on the anastomotic breaking strength on the third postoperative day in the small intestine of rabbits....

  3. Influence of TiC precipitation in austenitic stainless steel on strength, ductility and helium embrittlement

    International Nuclear Information System (INIS)

    Kesternich, W.; Matta, M.K.; Rothaut, J.

    1984-01-01

    Creep experiments were performed on 1.4970 (German DIN standard) and 316 (AISI standard) type austenitic steels after various thermomechanical pretreatments and after α-implantation. The microstructure introduced by the pretreatments was characterized by transmission electron microscopy and the behaviour of strength and ductility is correlated to the dislocation and precipitate distributions. He embrittlement can be suppressed in these simulation experiments when dispersive TiC precipitate distributions are produced by the proper pretreatments or are allowed to form during creep testing. It is shown that adequate pretreatment results in a significantly superior behaviour of the 1.4970 steel as compared to the 316 type steel in all three investigated properties, i.e. strength, ductility and resistance to He embrittlement. (orig.)

  4. The influence of lay-up and thickness on composite impact damage and compression strength

    Science.gov (United States)

    Guynn, E. G.; Obrien, T. K.

    1985-01-01

    The effects of composite stacking sequence, thickness, and percentage of zero-degree plies on the size, shape, and distribution of delamination through the laminate thickness and on residual compression strength following impact were studied. Graphite/epoxy laminates were impacted with an 0.5 inch diameter aluminum sphere at a specific low or high velocity. Impact damage was measured nondestructively by ultrasonic C-scans and X-radiography and destructively by the deply technique, and compression strength tests were performed. It was found that differences in compression failure strain due to stacking sequence were small, while laminates with very low percentages of zero-degree plies had similar failure loads but higher failure strains than laminates with higher percentages of zero-degree plies. Failure strain did not correlate with planar impact damage area, and delaminations in impact regions were associated with matrix cracking.

  5. Influence of Ovarian Hormones on Strength Loss in Healthy and Dystrophic Female Mice

    Science.gov (United States)

    Kosir, Allison M.; Mader, Tara L.; Greising, Angela G.; Novotny, Susan A.; Baltgalvis, Kristen A.; Lowe, Dawn A.

    2014-01-01

    Purpose The primary objective of this study was to determine if strength loss and recovery following eccentric contractions is impaired in healthy and dystrophic female mice with low levels of ovarian hormones. Methods Female C57BL/6 (wildtype) or mdx mice were randomly assigned to ovarian-intact (Sham) and ovariectomized (Ovx) groups. Anterior crural muscles were tested for susceptibility to injury from 150 or 50 eccentric contractions in wildtype and mdx mice, respectively. An additional experiment challenged mdx mice with a 2-wk treadmill running protocol followed by an eccentric contraction injury to posterior crural muscles. Functional recovery from injury was evaluated in wildtype mice by measuring isometric torque 3, 7, 14, or 21 days following injury. Results Ovarian hormone deficiency in wildtype mice did not impact susceptibility to injury as the ~50% isometric torque loss following eccentric contractions did not differ between Sham and Ovx mice (p=0.121). Similarly in mdx mice, hormone deficiency did not affect percent of pre injury isometric torque lost by anterior crural muscles following eccentric contractions (p=0.952), but the percent of pre injury torque in posterior crural muscles was lower in Ovx compared to Sham mice (p=0.014). Recovery from injury in wildtype mice was affected by hormone deficiency. Sham mice recovered pre injury isometric strength by 14 days (96 ± 2%) while Ovx mice maintained deficits at 14 and 21 days post injury (80 ± 3% and 84 ± 2%; phormone status did not impact the vulnerability of skeletal muscle to strength loss following eccentric contractions. However, ovarian hormone deficiency did impair the recovery of muscle strength in female mice. PMID:25255128

  6. Four chemical methods of porcelain conditioning and their influence over bond strength and surface integrity

    Science.gov (United States)

    Stella, João Paulo Fragomeni; Oliveira, Andrea Becker; Nojima, Lincoln Issamu; Marquezan, Mariana

    2015-01-01

    OBJECTIVE: To assess four different chemical surface conditioning methods for ceramic material before bracket bonding, and their impact on shear bond strength and surface integrity at debonding. METHODS: Four experimental groups (n = 13) were set up according to the ceramic conditioning method: G1 = 37% phosphoric acid etching followed by silane application; G2 = 37% liquid phosphoric acid etching, no rinsing, followed by silane application; G3 = 10% hydrofluoric acid etching alone; and G4 = 10% hydrofluoric acid etching followed by silane application. After surface conditioning, metal brackets were bonded to porcelain by means of the Transbond XP system (3M Unitek). Samples were submitted to shear bond strength tests in a universal testing machine and the surfaces were later assessed with a microscope under 8 X magnification. ANOVA/Tukey tests were performed to establish the difference between groups (α= 5%). RESULTS: The highest shear bond strength values were found in groups G3 and G4 (22.01 ± 2.15 MPa and 22.83 ± 3.32 Mpa, respectively), followed by G1 (16.42 ± 3.61 MPa) and G2 (9.29 ± 1.95 MPa). As regards surface evaluation after bracket debonding, the use of liquid phosphoric acid followed by silane application (G2) produced the least damage to porcelain. When hydrofluoric acid and silane were applied, the risk of ceramic fracture increased. CONCLUSIONS: Acceptable levels of bond strength for clinical use were reached by all methods tested; however, liquid phosphoric acid etching followed by silane application (G2) resulted in the least damage to the ceramic surface. PMID:26352845

  7. Influence of uncoated and coated plastic waste coarse aggregates to concrete compressive strength

    OpenAIRE

    Purnomo Heru; Pamudji Gandjar; Satim Madsuri

    2017-01-01

    The use of plastic waste as coarse aggregates in concrete is part of efforts to reduce environmental pollution. In one hand the use of plastic as aggregates can provide lighter weight of the concrete than concrete using natural aggregates, but on the other hand bond between plastic coarse aggregates and hard matrix give low concrete compressive strength. Improvement of the bond between plastic coarse aggregate and hard matrix through a sand coating to plastic coarse aggregate whole surface is...

  8. Influence of storage times on bond strength of resin cements to root canal

    Directory of Open Access Journals (Sweden)

    Matheus Coêlho Bandéca

    2010-03-01

    Full Text Available The resin cements are responsible to retention of the indirect materials decreasing marginal leakage, increasing failure resistance compared with conventional cementation. The cementation within root canal is very hard due unfavorable conditions regarding the application of adhesive techniques caused by inadequate access. Therefore, considering the possibility to decrease steps of cementation, this study was performed to evaluate the bond strength of self-adhesive resin cement (RelyX TM U100, 3M ESPE and resin cement combined with self-ecthing adhesive system (Panavia® F 2.0, Kuraray light-cured with Quartz Tungsten Halogen (QTH following storage at 37 °C immediately after light-curing, 24 and 48 hours and 7 days. The root canals were prepared to receive the glass fiber post in the depth of 10 mm, irrigated with 17% EDTA and NaOCl, rinsed with distilled water and dried using paper points. The roots were perpendicularly sectioned into approximately 1 mm thick sections, obtaining ninety-six slices (n = 12. The slices were trimmed using a cylindrical diamond bur in the proximal surfaces until it touched the post and attached into a device, which were mounted on a strength tester (Bisco and loaded in tension at a speed of 0.5 mm/min until failure occurred at specimens. The analysis of variance (ANOVA and Tukey's post-hoc tests showed significant statistical differences (P .05. The resin cements 24 and 48 hours after light-curing were statistically similar among themselves (P > .05. The both resin cement showed similar bond strength into root canal on different storage times. The highest bond strength values of the resin cements were showed 7 days after curing.

  9. Influence of surface treatment on shear bond strength of orthodontic brackets

    Directory of Open Access Journals (Sweden)

    Ione Helena Vieira Portella Brunharo

    2013-06-01

    Full Text Available INTRODUCTION: The shear bond strength of orthodontic brackets bonded to micro-hybrid and micro-particulate resins under different surface treatment methods was assessed. METHODS: Two hundred and eighty test samples were divided into 28 groups (n = 10, where 140 specimens were filled with Durafill micro-particulate resin and 140 with Charisma composite. In 140 samples, a coupling agent (silane was applied. The surface treatment methods were: Phosphoric and hydrofluoric acid etching, sodium bicarbonate and aluminum oxide blasting, stone and burs. A Universal Instron Machine was used to apply an occlusal shear force directly to the resin composite bracket surface at a speed of 0.5 mm/min. The means were compared using analysis of variance and multivariate regression to assess the interaction between composites and surface treatment methods. RESULTS: Means and standard deviations for the groups were: Sodium bicarbonate jet 11.27±2.78; burs 9.26±3.01; stone 7.95±3.67; aluminum oxide blasting 7.04±3.21; phosphoric acid 5.82±1.90; hydrofluoric acid 4.54±2.87, and without treatment 2.75±1.49. An increase of 1.94 MPa in shear bond strength was seen in Charisma groups. Silane agent application reduced the Charisma shear bond strength by 0.68 Mpa, but increased Durafill means for bicarbonate blasting (0.83, burs (0.98 and stone drilling (0.46. CONCLUSION: The sodium bicarbonate blasting, burs and stone drilling methods produced adequate shear bond strength and may be suitable for clinical use. The Charisma micro hybrid resin composite showed higher shear bond means than Durafill micro particle composite.

  10. Influence of surface treatment on shear bond strength of orthodontic brackets.

    Science.gov (United States)

    Brunharo, Ione Helena Vieira Portella; Fernandes, Daniel Jogaib; de Miranda, Mauro Sayão; Artese, Flavia

    2013-01-01

    The shear bond strength of orthodontic brackets bonded to micro-hybrid and micro-particulate resins under different surface treatment methods was assessed. Two hundred and eighty test samples were divided into 28 groups (n = 10), where 140 specimens were filled with Durafill micro-particulate resin and 140 with Charisma composite. In 140 samples, a coupling agent (silane) was applied. The surface treatment methods were: Phosphoric and hydrofluoric acid etching, sodium bicarbonate and aluminum oxide blasting, stone and burs. A Universal Instron Machine was used to apply an occlusal shear force directly to the resin composite bracket surface at a speed of 0.5 mm/min. The means were compared using analysis of variance and multivariate regression to assess the interaction between composites and surface treatment methods. Means and standard deviations for the groups were: Sodium bicarbonate jet 11.27 ± 2.78; burs 9.26 ± 3.01; stone 7.95 ± 3.67; aluminum oxide blasting 7.04 ± 3.21; phosphoric acid 5.82 ± 1.90; hydrofluoric acid 4.54 ± 2.87, and without treatment 2.75 ± 1.49. An increase of 1.94 MPa in shear bond strength was seen in Charisma groups. Silane agent application reduced the Charisma shear bond strength by 0.68 Mpa, but increased Durafill means for bicarbonate blasting (0.83), burs (0.98) and stone drilling (0.46). The sodium bicarbonate blasting, burs and stone drilling methods produced adequate shear bond strength and may be suitable for clinical use. The Charisma micro hybrid resin composite showed higher shear bond means than Durafill micro particle composite.

  11. Influence of Photoinitiator on Accelerated Artificial Aging and Bond Strength of Experimental Resin Cements.

    Science.gov (United States)

    Righi, Helouise; Costa, Ana Rosa; Oliveira, Dayane Carvalho Ramos Salles de; Abuna, Gabriel Flores; Sinhoreti, Mario Alexandre Coelho; Naufel, Fabiana Scarparo

    2018-01-01

    The goal of this study was to evaluate in vitro the effect of the photoinitiator phenylpropanedione (PPD), alone or combined with camphorquinone (CQ), on color stability of photoactivated resin cements and their bond strength to ceramics using a micro-shear test. Four resin cements were used: a commercial brand cement (RelyX Veneer®) and 3 experimental cements with different types and concentration of photoinitiators. For color analysis, ceramic discs were cemented on bovine dentin specimens to simulate indirect restorations (n=8) and were exposed to UV for 120 h and tested for color alteration using a reflectance spectrophotometer and the CIEL*a*b* system. Data were analyzed by Anova and Tukey's test at 5% significance level. The color test results did not present statistically significant difference for the ∆E for all the studied cements, neither for ∆L, ∆a and ∆b. For the bond strength, all the studied cements showed statistically significant differences to each other, with the highest result for the RelyX Veneer® (29.07 MPa) cement, followed by the cement with CQ (21.74 MPa) and CQ+PPD (19.09 MPa) cement; the lowest result was obtained by the cement using only PPD as a photoinitiator (13.99 MPa). So, based on the studied parameters, PPD was not advantageous as photoinitiator of resin cements, because it showed a low value of bond strength to the ceramics and no superior color stability.

  12. Affect influences feature binding in memory: Trading between richness and strength of memory representations.

    Science.gov (United States)

    Spachtholz, Philipp; Kuhbandner, Christof; Pekrun, Reinhard

    2016-10-01

    Research has shown that long-term memory representations of objects are formed as a natural product of perception even without any intentional memorization. It is not known, however, how rich these representations are in terms of the number of bound object features. In particular, because feature binding rests on resource-limited processes, there may be a context-dependent trade-off between the quantity of stored features and their memory strength. The authors examined whether affective state may bring about such a trade-off. Participants incidentally encoded pictures of real-world objects while experiencing positive or negative affect, and the authors later measured memory for 2 features. Results showed that participants traded between richness and strength of memory representations as a function of affect, with positive affect tuning memory formation toward richness and negative affect tuning memory formation toward strength. These findings demonstrate that memory binding is a flexible process that is modulated by affective state. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  13. Influence of uncoated and coated plastic waste coarse aggregates to concrete compressive strength

    Directory of Open Access Journals (Sweden)

    Purnomo Heru

    2017-01-01

    Full Text Available The use of plastic waste as coarse aggregates in concrete is part of efforts to reduce environmental pollution. In one hand the use of plastic as aggregates can provide lighter weight of the concrete than concrete using natural aggregates, but on the other hand bond between plastic coarse aggregates and hard matrix give low concrete compressive strength. Improvement of the bond between plastic coarse aggregate and hard matrix through a sand coating to plastic coarse aggregate whole surface is studied. Sand used to coat the plastic aggregates are Merapi volcanic sand which are taken in Magelang. Three mixtures of polypropylene (PP coarse plastic aggregates, Cimangkok river sand as fine aggregates, water and Portland Cement Composite with a water-cement ratio of 0.28, 0.3 and 0.35 are conducted. Compression test are performed on concrete cylindrical specimens with a diameter of 10 cm and a height of 20 cm. The results in general show that concrete specimens using plastic aggregates coated with sand have higher compressive strength compared to those of concrete specimens using plastic aggregates without sand coating. The bond improvement is indirectly indicated by the betterment of concrete compressive strength.

  14. Influence of bagasse ash and recycled concrete aggregate on hardened properties of high-strength concrete

    Directory of Open Access Journals (Sweden)

    P. Rattanachu

    2018-04-01

    Full Text Available This research aimed to use of bagasse ash as a cement replacement in high-strength recycled aggregate concrete (HS-RAC. Crushed limestone was replaced with 100% recycled concrete aggregate (RCA and the ground bagasse ash (GBA was used to partially replace ordinary Portland cement (OPC at 20, 35 and 50%wt of binder to cast HS-RAC. The results indicated that the replacing of crushed limestone with RCA had a negative impact on the properties of the concrete. Increasing the amount of GBA in HS-RAC resulted in a decrease in density and an increase in the volume of permeable pore space. The concrete mixtures prepared with 20%wt GBA replacement of OPC promoted greater the compressive strength than the conventional concrete (CT concrete at 90 days or more. HS-RAC with GBA (up to 50% was more durable in terms of chloride ion penetration resistance, although it had lower compressive strength than the CT concrete.

  15. A randomized controlled trial on the effectiveness of strength training on clinical and muscle cellular outcomes in patients with prostate cancer during androgen deprivation therapy: rationale and design

    International Nuclear Information System (INIS)

    Thorsen, Lene; Nilsen, Tormod S; Raastad, Truls; Courneya, Kerry S; Skovlund, Eva; Fosså, Sophie D

    2012-01-01

    Studies indicate that strength training has beneficial effects on clinical health outcomes in prostate cancer patients during androgen deprivation therapy. However, randomized controlled trials are needed to scientifically determine the effectiveness of strength training on the muscle cell level. Furthermore, close examination of the feasibility of a high-load strength training program is warranted. The Physical Exercise and Prostate Cancer (PEPC) trial is designed to determine the effectiveness of strength training on clinical and muscle cellular outcomes in non-metastatic prostate cancer patients after high-dose radiotherapy and during ongoing androgen deprivation therapy. Patients receiving androgen deprivation therapy for 9-36 months combined with external high-dose radiotherapy for locally advanced prostate cancer are randomized to an exercise intervention group that receives a 16 week high-load strength training program or a control group that is encouraged to maintain their habitual activity level. In both arms, androgen deprivation therapy is continued until the end of the intervention period. Clinical outcomes are body composition (lean body mass, bone mineral density and fat mass) measured by Dual-energy X-ray Absorptiometry, serological outcomes, physical functioning (muscle strength and cardio-respiratory fitness) assessed with physical tests and psycho-social functioning (mental health, fatigue and health-related quality of life) assessed by questionnaires. Muscle cellular outcomes are a) muscle fiber size b) regulators of muscle fiber size (number of myonuclei per muscle fiber, number of satellite cells per muscle fiber, number of satellite cells and myonuclei positive for androgen receptors and proteins involved in muscle protein degradation and muscle hypertrophy) and c) regulators of muscle fiber function such as proteins involved in cellular stress and mitochondrial function. Muscle cellular outcomes are measured on muscle cross sections and

  16. Hepatitus B virus infection : factors influencing the outcome

    NARCIS (Netherlands)

    J. van Hattum (Jan)

    1986-01-01

    textabstractThis study was designed to find correlations between the various courses of disease after hepatitis B virus (HBV) infection and factors that could conceivably have influenced the course of disease. The aim of the study was to find correlations between parameters of viral replication and

  17. Social network influences on technology acceptance : A matter of tie strength, centrality and density

    NARCIS (Netherlands)

    Ten Kate, Stephan; Haverkamp, Sophie; Mahmood, Fariha; Feldberg, Frans

    2010-01-01

    This study examines social network influences on the individual technology acceptance. Since it is believed that individuals' trust, opinions and behavior are influenced by their network, an analysis of that network may help to provide some explanations on technology acceptance. However, since

  18. Forewarned is forearmed : Conserving self-control strength to resist social influence

    NARCIS (Netherlands)

    Janssen, Loes; Fennis, Bob M.; Pruyn, Ad Th. H.

    2010-01-01

    Recent research has shown that resisting persuasion involves active self-regulation. Resisting an influence attempt consumes self-regulatory resources, and in a state of self-regulatory resource depletion, people become more susceptible to (unwanted) influence attempts. However, the present studies

  19. Modulating influences of memory strength and sensitivity of the retrieval test on the detectability of the sleep consolidation effect.

    Science.gov (United States)

    Schoch, Sarah F; Cordi, Maren J; Rasch, Björn

    2017-11-01

    Emotionality can increase recall probability of memories as emotional information is highly relevant for future adaptive behavior. It has been proposed that memory processes acting during sleep selectively promote the consolidation of emotional memories, so that neutral memories no longer profit from sleep consolidation after learning. This appears as a selective effect of sleep for emotional memories. However, other factors contribute to the appearance of a consolidation benefit and influence this interpretation. Here we show that the strength of the memory trace before sleep and the sensitivity of the retrieval test after sleep are critical factors contributing to the detection of the benefit of sleep on memory for emotional and neutral stimuli. 228 subjects learned emotional and neutral pictures and completed a free recall after a 12-h retention interval of either sleep or wakefulness. We manipulated memory strength by including an immediate retrieval test before the retention interval in half of the participants. In addition, we varied the sensitivity of the retrieval test by including an interference learning task before retrieval testing in half of the participants. We show that a "selective" benefit of sleep for emotional memories only occurs in the condition with high memory strength. Furthermore, this "selective" benefit disappeared when we controlled for the memory strength before the retention interval and used a highly sensitive retrieval test. Our results indicate that although sleep benefits are more robust for emotional memories, neutral memories similarly profit from sleep after learning when more sensitive indicators are used. We conclude that whether sleep benefits on memory appear depends on several factors, including emotion, memory strength and sensitivity of the retrieval test. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Influence of the Testing Gage Length on the Strength, Young's Modulus and Weibull Modulus of Carbon Fibres and Glass Fibres

    Directory of Open Access Journals (Sweden)

    Luiz Claudio Pardini

    2002-10-01

    Full Text Available Carbon fibres and glass fibres are reinforcements for advanced composites and the fiber strength is the most influential factor on the strength of the composites. They are essentially brittle and fail with very little reduction in cross section. Composites made with these fibres are characterized by a high strength/density ratio and their properties are intrisically related to their microstructure, i.e., amount and orientation of the fibres, surface treatment, among other factors. Processing parameters have an important role in the fibre mechanical behaviour (strength and modulus. Cracks, voids and impurities in the case of glass fibres and fibrillar misalignments in the case of carbon fibres are created during processing. Such inhomogeneities give rise to an appreciable scatter in properties. The most used statistical tool that deals with this characteristic variability in properties is the Weibull distribution. The present work investigates the influence of the testing gage length on the strength, Young's modulus and Weibull modulus of carbon fibres and glass fibres. The Young's modulus is calculated by two methods: (i ASTM D 3379M, and (ii interaction between testing equipment/specimen The first method resulted in a Young modulus of 183 GPa for carbon fibre, and 76 GPa for glass fibre. The second method gave a Young modulus of 250 GPa for carbon fibre and 50 GPa for glass fibre. These differences revelead differences on how the interaction specimen/testing machine can interfere in the Young modulus calculations. Weibull modulus can be a tool to evaluate the fibre's homogeneity in terms of properties and it is a good quality control parameter during processing. In the range of specimen gage length tested the Weibull modulus for carbon fibre is ~ 3.30 and for glass fibres is ~ 5.65, which indicates that for the batch of fibres tested, the glass fibre is more uniform in properties.

  1. Influence of Fatigue on Tackling Ability in Rugby League Players: Role of Muscular Strength, Endurance, and Aerobic Qualities.

    Directory of Open Access Journals (Sweden)

    Tim J Gabbett

    Full Text Available This study investigated the influence of repeated high-intensity effort exercise on tackling ability in rugby league players, and determined the relationship between physical qualities and tackling ability under fatigued conditions in these athletes. Eleven semi-professional rugby league players underwent measurements of speed (10 m and 40 m sprint, upper-body strength (4 repetition maximum [RM] bench press and weighted chin-up, upper-body muscular endurance (body mass maximum repetition chin-up, body mass maximum repetition dips, lower-body strength (4RM squat, and estimated maximal aerobic power (multi-stage fitness test. Tackling ability was assessed using a standardized one-on-one tackling test, before, during, and following four bouts of repeated high-intensity effort (RHIE exercise. The relationship between physical qualities and fatigue-induced decrements in tackling ability were determined using Pearson product moment correlation coefficients. Each cycle of the RHIE protocol induced progressive reductions in tackling ability. A moderate reduction (Effect Size = ~-1.17 ± 0.60, -34.1 ± 24.3% in tackling ability occurred after the fourth cycle of the RHIE protocol. Players with greater relative lower-body strength (i.e. 4RM squat/kg had the best tackling ability under fatigued conditions (r = 0.72, p = 0.013. There were no significant relationships between tackling ability under fatigued conditions and any other physical quality. These findings suggest that lower-body strength protects against fatigue-induced decrements in tackling ability. The development of lower-body strength should be a priority to facilitate the development of robust tackling skills that are maintained under fatigue.

  2. Leader Affect and Leadership Effectiveness: How leader affective displays influence follower outcomes

    NARCIS (Netherlands)

    V.A. Visser (Victoria)

    2013-01-01

    textabstractThe aim of this dissertation is to uncover the relationship between leader affective displays and leadership effectiveness. Five empirical studies were conducted to test the influence of several leader affective displays on different follower outcomes that indicate leadership

  3. The influence of neck thrombus on clinical outcome and aneurysm morphology after endovascular aneurysm repair

    NARCIS (Netherlands)

    F.M.V. Bastos Gonçalves (Frederico); H.J.M. Verhagen (Hence); K. Chinsakchai (Khamin); J.W. van Keulen (Jasper); M.T. Voûte (Michiel); H.J.A. Zandvoort (Herman); F.L. Moll (Frans); J.A. van Herwaarden (Joost)

    2012-01-01

    textabstractObjective: This study investigated the influence of significant aneurysm neck thrombus in clinical and morphologic outcomes after endovascular aneurysm repair (EVAR). Methods: The patient population was derived from a prospective EVAR database from two university institutions in The

  4. Influence of cement compressive strength and porosity on augmentation performance in a model of orthopedic screw pull-out.

    Science.gov (United States)

    Pujari-Palmer, Michael; Robo, Celine; Persson, Cecilia; Procter, Philip; Engqvist, Håkan

    2018-01-01

    Disease and injuries that affect the skeletal system may require surgical intervention and internal fixation, i.e. orthopedic plate and screw insertion, to stabilize the injury and facilitate tissue repair. If the surrounding bone quality is poor the screws may migrate, or the bone may fail, resulting in fixation failure. While numerous studies have shown that cement augmentation of the interface between bone and implant can increase screw pull-out force, the physical properties of cement that influence pull-out force have not been investigated. The present study sought to determine how the physical properties of high strength calcium phosphate cements (hsCPCs, specifically dicalcium phosphate) affected the corresponding orthopedic screw pull-out force in urethane foam models of "healthy" and "osteoporotic" synthetic bone (Sawbones). In the simplest model, where only the bond strength between screw thread and cement (without Sawbone) was tested, the correlation between pull-out force and cement compressive strength (R 2 = 0.79) was weaker than correlation with total cement porosity (R 2 = 0.89). In open pore Sawbone that mimics "healthy" cancellous bone density the stronger cements produced higher pull-out force (50-60% increase). High strength, low porosity cements also produced higher pull-out forces (50-190% increase) in "healthy" Sawbones with cortical fixation if the failure strength of the cortical material was similar to, or greater than (a metal shell), actual cortical bone. This result is of particular clinical relevance where fixation with a metal plate implant is indicated, as the nearby metal can simulate a thicker cortical shell, thereby increasing the pull-out force of screws augmented with stronger cements. The improvement in pull-out force was apparent even at low augmentation volumes of 0.5mL (50% increase), which suggest that in clinical situations where augmentation volume is limited the stronger, lower porosity calcium phosphate cement (CPC) may

  5. Influence of sodalite zeolite infiltration on the coefficient of thermal expansion and bond strength of all-ceramic dental prostheses.

    Science.gov (United States)

    Naji, Ghassan Abdul-Hamid; Omar, Ros Anita; Yahya, Rosiyah

    2017-03-01

    In all-ceramic systems, a high incidence of veneer chip-off has been reported in clinical studies. Coefficient of thermal expansion (CTE) behaviour is one of the factors that may increase residual stress in the interface and influence the veneer/core bond strength. Therefore, this study aimed to evaluate the effect of sodalite zeolite-infiltration on the CTE behaviour and bond strength of different all-ceramic prostheses. The case-study groups were synthesized sodalite zeolite-infiltrated alumina (IA-SOD) and synthesized sodalite zeolite-infiltrated zirconia-toughened alumina (ZTA) (IZ-SOD), while the control groups were glass-infiltrated alumina (IA-glass) and glass-infiltrated ZTA (IZ-glass). Forty cylindrical-shaped samples measuring 5 mm in diameter and 10 mm in height were tested for CTE using a thermo-mechanical analyser machine, and forty disc-shaped ceramic samples measuring 12 mm in diameter and 1.2 ± 0.2 mm in thickness were prepared using specially designed stainless steel split mould and veneered by cylinder-shaped (2 mm high × 2 mm diameter) low-fusing porcelain (Vita VM7). The veneer/core samples were sintered and tested for shear bond strength using a high precision universal testing machine. Scanning electron microscope, stereo microscope, atomic force microscope, and energy-dispersive X-ray spectroscopy were used to investigate the structural characteristics of samples at the fracture surface. The collected data were analyzed with a one-way ANOVA and Tukey HSD test (α=.05). IZ-SOD revealed highest CTE and shear bond strength values, while the IA-glass revealed the lowest values than the other groups. There was no significant difference in CTE and bond strength among IZ-SOD, IA-SOD and IZ-glass samples (p>0.05). The experimental SOD zeolite-infiltrated samples revealed higher CTE mismatch and bond strength along with a more favourable mode of failure than did the commercial glass-infiltrated samples. Sandblast technique is considered as effective

  6. Influence of dentin contamination by temporary cements on the bond strength of adhesive systems

    Directory of Open Access Journals (Sweden)

    Josimeri Hebling

    2009-01-01

    Full Text Available Objective: The aim of this study was to assess the bond strength of adhesive systems to dentin contaminated by temporary cements with or without eugenol. Method: Flat dentin surfaces were obtained from twenty-four human third molars. With exception of the control group (n=8, the surfaces were covered with Interim Restorative Material (Caulk Dentsplay, Milford, DE, USA or Cavit (3M ESPE, St. Paul, MN, USA and kept in an oven at 37oC for seven days. After removing the cements, the adhesive systems Adper Single Bond (3M ESPE, St. Paul, MN, USA or Clearfil SE Bond (Kuraray Co. Ltd., Osaka, Japan were applied in accordance with the manufacturers’ recommendations, and then the crowns were constructed in of resin composite. The teeth were sectioned into specimens with a cross-sectional bond area of 0.81mm2, which were sub mitted to microtensile testing in a mechanical test machine at an actuator speed of 0.5mm/min. The data were analyzed by t- and ANOVA tests, complemented by Tukey tests (α=0.05. Results: For Adper Single Bond (3M ESPE, St. Paul, MN, USA, bond strength did not differ statistically (p>0.05 for all the experimental conditions. For Clearfil SE Bond (Kuraray Co. Ltd., Osaka, Japan, only the Interim Restorative Material (Caulk Dentsplay, Milford, DE, USA Group showed significantly lower bond strength (30.1±13.8 MPa in comparison with the other groups; control (38.9±13.5 MPa and Cavit (3M ESPE, St. Paul, MN, USA (42.1±11.0 MPa, which showed no significant difference between them.Conclusion: It was concluded that the previous covering of dentin with temporary cement containing eugenol had a deleterious effect on the adhesive performance of the self-etching system only.

  7. Influence of saliva contamination on the shear bond strength of adhesives on enamel

    Directory of Open Access Journals (Sweden)

    Tatiana Feres Assad-Loss

    2012-04-01

    Full Text Available OBJECTIVE: To evaluate shear bond strength of 3 adhesive systems (Single Bond, TransbondTM MIP and TransbondTM XT applied on bovine enamel under saliva contamination condition. METHOD: One hundred and twenty enamel surfaces of bovine incisors were divided into 6 groups (n = 20 according to the adhesive system used (TransbondTM XT, TransbondTM MIP and Single Bond with or without saliva contamination. For each adhesive system, there were two groups defined as no contamination group (NC: 37% H3PO4 conditioning for 30 seconds and two layers of adhesive systems; saliva contamination group (SC: After the first adhesive layer application, the examined areas were contaminated with saliva. Samples were mounted appropriately for testing and stored in deionized water at 37 ºC for 7 days. Samples were then submitted to shear bond strength trials at a speed of 0.5 mm/min. The Adhesive Remnant Index (ARI was evaluated under stereomicroscopy. Two-way analysis of variance and the Tukey test were used to compare mean values (α = 0.05. RESULTS: Groups XT (NC = 26.29 ± 7.23; MIP (NC = 24.47 ± 7.52 and SB (NC = 32.36 ± 4.14 XT (SC = 19.59 ± 6.76; MIP (SC = 18.08 ± 6.39 and SB (SC = 18.18 ± 7.03 MPa. ARI 0 and 1 were the most prevalent scores in all study groups examined. CONCLUSION: Saliva contamination significantly decreased bond strength of the three adhesive systems examined (p <0.05. However, the comparison of groups with and without saliva contamination did not reveal any significant differences, and, therefore, the three systems may be considered equivalent.

  8. Influence of Different Etching Modes on Bond Strength to Enamel using Universal Adhesive Systems.

    Science.gov (United States)

    Diniz, Ana Cs; Bandeca, Matheus C; Pinheiro, Larissa M; Dos Santosh Almeida, Lauber J; Torres, Carlos Rg; Borges, Alvaro H; Pinto, Shelon Cs; Tonetto, Mateus R; De Jesus Tavarez, Rudys R; Firoozmand, Leily M

    2016-10-01

    The adhesive systems and the techniques currently used are designed to provide a more effective adhesion with reduction of the protocol application. The objective of this study was to evaluate the bond strength of universal adhesive systems on enamel in different etching modes (self-etch and total etch). The mesial and distal halves of 52 bovine incisors, healthy, freshly extracted, were used and divided into seven experimental groups (n = 13). The enamel was treated in accordance with the following experimental conditions: FUE-Universal System - Futurabond U (VOCO) with etching; FUWE - Futurabond U (VOCO) without etching; SB-Total Etch System - Single Bond 2 (3M); SBUE-Universal System - Single Bond Universal (3M ESPE) with etching; SBUWE - Single Bond Universal (3M ESPE) without etching; CLE-Self-etch System - Clearfil SE Bond (Kuraray) was applied with etching; CLWE - Clearfil SE Bond (Kuraray) without etching. The specimens were made using the composite spectrum TPH (Dentsply) and stored in distilled water (37 ± 1°C) for 1 month. The microshear test was performed using the universal testing machine EMIC DL 2000 with the crosshead speed of 0.5 mm/minute. The bond strength values were analyzed using statistical tests (Kruskal-Wallis test and Mann-Whitney test) with Bonferroni correction. There was no statistically significant difference between groups (p adhesive interface revealed that most failures occurred between the interface composite resin and adhesive. The universal adhesive system used in dental enamel varies according to the trademark, and the previous enamel etching for universal systems and the self-etch both induced greater bond strength values. Selective enamel etching prior to the application of a universal adhesive system is a relevant strategy for better performance bonding.

  9. Influence of Cognitive Ability on Therapy Outcomes for Anomia in Adults with Chronic Poststroke Aphasia

    Science.gov (United States)

    Dignam, Jade; Copland, David; O'Brien, Kate; Burfein, Penni; Khan, Asaduzzaman; Rodriguez, Amy D.

    2017-01-01

    Purpose: The relationship between cognitive abilities and aphasia rehabilitation outcomes is complex and remains poorly understood. This study investigated the influence of language and cognitive abilities on anomia therapy outcomes in adults with aphasia. Method: Thirty-four adults with chronic aphasia participated in Aphasia Language Impairment…

  10. Cooperative context is a determinant of the social influence on outcome evaluation: An electrophysiological study.

    Science.gov (United States)

    Kimura, Kenta; Katayama, Jun'ichi

    2016-02-01

    The present study examined whether or not a cooperative context is a determinant of the social influence on the evaluation of two action outcomes: a monetary outcome and a conflict of opinion with other group members. In the present study, three-person groups were randomly assigned to be either a cooperative or individual group and asked to perform a gambling task. The monetary outcomes in the cooperative group were interrelated among group members, whereas those in the individual group did not influence each other. The present results showed that monetary outcomes elicited feedback-related negativity (FRN) and a conflict of opinion with other group members elicited FRN-like negativity, which reflect an evaluation of the motivational significance of action outcomes. The FRN elicited by monetary outcomes was reduced when participants shared decisions with other group members only in the cooperative group, indicating that the cooperative context reduced the motivational significance of monetary outcomes through the diffusion of responsibility. The FRN-like negativity elicited by a conflict of opinion showed a different pattern between the cooperative and individual groups, indicating that the cooperative context can influence the evaluation of a conflict of opinion, possibly via the modulation of group cohesiveness or conflict processing. The present results suggest that a cooperative context, rather than the social setting, is a determinant of the social influence on outcome evaluation. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. The Influence of Negligence, Intention, and Outcome on Children's Moral Judgments

    Science.gov (United States)

    Nobes, Gavin; Panagiotaki, Georgia.; Pawson, Chris

    2009-01-01

    Piaget (1932) and subsequent researchers have reported that young children's moral judgments are based more on the outcomes of actions than on the agents' intentions. The current study investigated whether negligence might also influence these judgments and explain children's apparent focus on outcome. Children (3-8 years of age) and adults (N =…

  12. INFLUENCE OF PERSONALITY ON THE OUTCOME OF TREATMENT IN DEPRESSION : SYSTEMATIC REVIEW AND META-ANALYSIS

    NARCIS (Netherlands)

    Newton-Howes, Giles; Tyrer, Peter; Johnson, Tony; Mulder, Roger; Kool, Simone; Dekker, Jack; Schoevers, Robert

    There continues to be debate about the influence of personality disorder on the outcome of depressive disorders and is relative interactions with treatment. To determine whether personality disorder, both generically and in terms of individual clusters, leads to a worse outcome in patients with

  13. Influence of application methods of one-step self-etching adhesives on microtensile bond strength

    OpenAIRE

    Chul-Kyu Choi,; Sung-Ae Son; Jin-Hee Ha; Bock Hur; Hyeon-Cheol Kim; Yong-Hun Kwon; Jeong-Kil Park

    2011-01-01

    Objectives The purpose of this study was to evaluate the effect of various application methods of one-step self-etch adhesives to microtensile resin-dentin bond strength. Materials and Methods Thirty-six extracted human molars were used. The teeth were assigned randomly to twelve groups (n = 15), according to the three different adhesive systems (Clearfil Tri-S Bond, Adper Prompt L-Pop, G-Bond) and application methods. The adhesive systems were applied on the dentin as follows: 1) T...

  14. Irreversible traps, their influence on the embrittlement of high strength steel

    International Nuclear Information System (INIS)

    Mariano, I; Mansilla, G

    2012-01-01

    Hydrogen (H) can be trapped in lattice defects such as vacancies, dislocations, grain boundaries and interfaces between the matrix and precipitates. The effect on the mechanical properties depends on factors inherent in materials such as the activation energy of irreversible traps (H trapped in Network Places) and its sensitivity to embrittlement. Differential scanning calorimetry (DSC) allows the study of those processes in which enthalpy variation occurs. The purpose is to record the difference in enthalpy change that occurs in the sample as a function of temperature or time. This work represents a study of H embrittlement of high strength steel resulfurized

  15. On the influence of crack closure on strength estimates of wood

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    2004-01-01

    Three well-known duration of load models (Gerhard, Barrett/Foschi, DVM) are considered in this note with respect to their ability to predict lifetime of wood subjected to harmonically varying loads. The result obtained is that they practically predict the same lifetime—which for low frequency...... in metals).It is suggested that any of the simple models can be used in practice when low frequency load variations are considered. The DVM model, however, should be preferred because of its ability to predict residual strength, and because of its ‘build in’ flexibility with respect to wood quality...

  16. INFLUENCE OF AMNIOTIC FLUID INDEX ON FOETAL OUTCOME

    Directory of Open Access Journals (Sweden)

    Raja Lakshmi

    2015-03-01

    Full Text Available BACKGROUND AND OBJECTIVE: In these days of smaller families and the obstetrician having to share the onus of giving a healthy child capable of independent existence as well as to ensure that the population is limited for further progress of this developing country, the estimation o f foetal maturity assumes greatest practical importance. As means to achieving the end, estimates of foetal maturity have been done by various clinical and laboratory methods of which assessment of amniotic fluid index assumes importance. The objective is to study the correlation of amniotic fluid index on foetal outcome at term gestation . MATERIALS AND METHODS: The study was carried out on two hundred antenatal women who attended the institute of obstetrics and gynaecology at a Government Hospital for Wome n and Children in Visakhapatnam from Jan 2014 to Jan 2015. It is a comparative prospective study comparing 100 cases of Oligohydramnios (amniotic fluid index 5 cm as control group. RESU LTS : Perinatal outcome was inferred by noting the various parameters and Statistical Analysis was done by applying the chisquare (x2 test and the value of probability was taken . CONCLUSION: The goal of antepartum fetal surveillance is to identify the fetu s at increased risk. Amniotic fluid volume has been proved as an indirect measure of feto - placental function and hence the estimation of amniotic fluid volume assists the obstetrician in risk assessment

  17. Influence of surface defects on the tensile strength of carbon fibers

    Science.gov (United States)

    Vautard, F.; Dentzer, J.; Nardin, M.; Schultz, J.; Defoort, B.

    2014-12-01

    The mechanical properties of carbon fibers, especially their tensile properties, are affected by internal and surface defects. In order to asses in what extent the generation of surface defects can result in a loss of the mechanical properties, non-surface treated carbon fibers were oxidized with three different surface treatment processes: electro-chemical oxidation, oxidation in nitric acid, and oxidation in oxygen plasma. Different surface topographies and surface chemistries were obtained, as well as different types and densities of surface defects. The density of surface defects was measured with both a physical approach (Raman spectroscopy) and a chemical approach (Active Surface Area). The tensile properties were evaluated by determining the Weibull modulus and the scale parameter of each reference, after measuring the tensile strength for four different gauge lengths. A relationship between the tensile properties and the nature and density of surface defects was noticed, as large defects largely control the value of the tensile strength. When optimized, some oxidation surface treatment processes can generate surface functional groups as well as an increase of the mechanical properties of the fibers, because of the removal of the contamination layer of pyrolytic carbon generated during the carbonization of the polyacrylonitrile precursor. Oxidation in oxygen plasma revealed to be a promising technology for alternative surface treatment processes, as high levels of functionalization were achieved and a slight improvement of the mechanical properties was obtained too.

  18. Influence of Pre-Sintered Zirconia Surface Conditioning on Shear Bond Strength to Resin Cement

    Directory of Open Access Journals (Sweden)

    Tomofumi Sawada

    2016-06-01

    Full Text Available This study analyzed the shear bond strength (SBS of resin composite on zirconia surface to which a specific conditioner was applied before sintering. After sintering of either conditioner-coated or uncoated specimens, both groups were divided into three subgroups by their respective surface modifications (n = 10 per group: no further treatment; etched with hydrofluoric acid; and sandblasted with 50 µm Al2O3 particles. Surfaces were characterized by measuring different surface roughness parameters (e.g., Ra and Rmax and water contact angles. Half of the specimens underwent thermocycling (10,000 cycles, 5–55 °C after self-adhesive resin cement build-up. The SBSs were measured using a universal testing machine, and the failure modes were analyzed by microscopy. Data were analyzed by nonparametric and parametric tests followed by post-hoc comparisons (α = 0.05. Conditioner-coated specimens increased both surface roughness and hydrophilicity (p < 0.01. In the non-thermocycled condition, sandblasted surfaces showed higher SBSs than other modifications, irrespective of conditioner application (p < 0.05. Adhesive fractures were commonly observed in the specimens. Thermocycling favored debonding and decreased SBSs. However, conditioner-coated specimens upon sandblasting showed the highest SBS (p < 0.05 and mixed fractures were partially observed. The combination of conditioner application before sintering and sandblasting after sintering showed the highest shear bond strength and indicated improvements concerning the failure mode.

  19. The influence of the grain boundary strength on the macroscopic properties of a polycrystalline aggregate

    International Nuclear Information System (INIS)

    Simonovski, Igor; Cizelj, Leon; Garrido, Oriol Costa

    2013-01-01

    Highlights: ► Grain boundary stiffness should be at least 1.5× higher that the stiffness of bulk grains. ► The ratio δ n pl /δ n el should be at least 400. ► Simultaneous increase of δ n el and δ n pl at constant grain boundary strength increases numerical stability but results in high percentage of damage grain boundary area. ► Shear contributes significantly to damage initialization. -- Abstract: In this work a model, based on a X-ray diffraction contrast tomography data of a stainless steel wire with a diameter of 0.4 mm is presented. As measured 3D grain geometry and crystallographic orientation of individual grains are directly transferred into a finite element model. Anisotropic elasticity and crystal plasticity constitutive laws are used for the bulk grain material while the grain boundaries are explicitly modeled using the cohesive zone approach. A parametric study on the effects of the grain boundary strength and other cohesive zone parameters on the macroscopic response and damaged grain boundary area of a polycrystalline aggregate is presented. Recommendations for the cohesive zone parameters values aimed at achieving low damaged grain boundary area during numerical tensile tests are given while at the same time taking into account the numerical stability of the simulations

  20. The influence of the grain boundary strength on the macroscopic properties of a polycrystalline aggregate

    Energy Technology Data Exchange (ETDEWEB)

    Simonovski, Igor, E-mail: Igor.Simonovski@ec.europa.eu [European Commission, DG-JRC, Institute for Energy and Transport, P.O. Box 2, NL-1755 ZG Petten (Netherlands); Cizelj, Leon, E-mail: Leon.Cizelj@ijs.si [Jožef Stefan Institute, Reactor Engineering Division, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); Garrido, Oriol Costa, E-mail: Oriol.Costa@ijs.si [Jožef Stefan Institute, Reactor Engineering Division, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia)

    2013-08-15

    Highlights: ► Grain boundary stiffness should be at least 1.5× higher that the stiffness of bulk grains. ► The ratio δ{sub n}{sup pl}/δ{sub n}{sup el} should be at least 400. ► Simultaneous increase of δ{sub n}{sup el} and δ{sub n}{sup pl} at constant grain boundary strength increases numerical stability but results in high percentage of damage grain boundary area. ► Shear contributes significantly to damage initialization. -- Abstract: In this work a model, based on a X-ray diffraction contrast tomography data of a stainless steel wire with a diameter of 0.4 mm is presented. As measured 3D grain geometry and crystallographic orientation of individual grains are directly transferred into a finite element model. Anisotropic elasticity and crystal plasticity constitutive laws are used for the bulk grain material while the grain boundaries are explicitly modeled using the cohesive zone approach. A parametric study on the effects of the grain boundary strength and other cohesive zone parameters on the macroscopic response and damaged grain boundary area of a polycrystalline aggregate is presented. Recommendations for the cohesive zone parameters values aimed at achieving low damaged grain boundary area during numerical tensile tests are given while at the same time taking into account the numerical stability of the simulations.

  1. Determination of Bond Capacity in Reinforced Concrete Beam and Its Influence on the Flexural Strength

    Directory of Open Access Journals (Sweden)

    Mohammad Rashidi

    2016-05-01

    Full Text Available This paper presents results of an experimental investigation of actual performance of the reinforced concrete beam in bond under flexure, when reinforced with tension steel is going to consider. In this experiment four specimens of beam and a bar in the middle of the width of the beam has been used and 2.5 cm of concrete cover has been considered from the center of the bar. In addition, transverse bars have been used to reassure lack of shear yield at the two ends of the beam. Flexural bar has been put in the middle of the beam symmetrically and the length of the flexural bar in each of the samples shall be: 15, 20, 30 and 40 cm. Three cylindrical samples were made in order to determine f’c and were examined at 28 days and the compressive strength of concrete used in this study was about 35 MPa. The beam samples were examined after 28 days via two-point loading system. Based on the results, increasing the length of bar causes increase of flexural strength. The presence of longitudinal rebar resulted in the ultimate momentum to be more than the crack momentum of the cross-section in parts which have broken at the point of longitudinal bar cut.

  2. Influence of non-metallic second phases on fatigue behaviour of high strength steel components

    International Nuclear Information System (INIS)

    Gonzalez, L.; Elvira, R.; Garcia de Andoin, A.; Pizarro, R.; Bertrand, C.

    2005-01-01

    To assess the real effect of the inclusion type on fatigue life of ultra clean high strength steels mechanical components made of 100Cr6 steel were fatigue tested and fracture surfaces analysed to determine the origin of fatigue cracks.Two heats proceedings from different steelmaking routes were taken for the tests. The material were forged into ring shape components which were fatigue tested under compression-compression loads. Failures were analysed by SFEM (Scanning field Emission Microscopy), proving that most of failures at high loads were originated by manganese sulphides of small size (10-70 micros), while less than 40% of all fatigue cracks due to inclusions were caused by titanium carbonitrides and hard oxides. It has been demonstrated that once number and size of hard inclusions have been reduced, the hazardous effect of oxides and carbonitrides on the fatigue life decreases also. However, softer inclusions as manganese sulphides, currently considered as less hazardous, play a more relevant role as direct cause of fatigue failure and they should be taken into account in a deeper way in order to balance both machinability and fatigue life requirements in high strength steel components. (Author) 11 refs

  3. Influence of laser etching on enamel and dentin bond strength of Silorane System Adhesive.

    Science.gov (United States)

    Ustunkol, Ildem; Yazici, A Ruya; Gorucu, Jale; Dayangac, Berrin

    2015-02-01

    The aim of this in vitro study was to evaluate the shear bond strength (SBS) of Silorane System Adhesive to enamel and dentin surfaces that had been etched with different procedures. Ninety freshly extracted human third molars were used for the study. After the teeth were embedded with buccal surfaces facing up, they were randomly divided into two groups. In group I, specimens were polished with a 600-grit silicon carbide (SiC) paper to obtain flat exposed enamel. In group II, the overlying enamel layer was removed and exposed dentin surfaces were polished with a 600-grit SiC paper. Then, the teeth in each group were randomly divided into three subgroups according to etching procedures: etched with erbium, chromium:yttrium-scandium-gallium-garnet laser (a), etched with 35% phosphoric acid (b), and non-etched (c, control). Silorane System Adhesive was used to bond silorane restorative to both enamel and dentin. After 24-h storage in distilled water at room temperature, a SBS test was performed using a universal testing machine at a crosshead speed of 1 mm/min. The data were analyzed using two-way ANOVA and Bonferroni tests (p enamel and dentin (p > 0.05). The SBS of self-etch adhesive to dentin was not statistically different from enamel (p > 0.05). Phosphoric acid treatment seems the most promising surface treatment for increasing the enamel and dentin bond strength of Silorane System Adhesive.

  4. [Influence of disc height on outcome of posterolateral fusion].

    Science.gov (United States)

    Drain, O; Lenoir, T; Dauzac, C; Rillardon, L; Guigui, P

    2008-09-01

    Experimentally, posterolateral fusion only provides incomplete control of flexion-extension, rotation and lateral inclination forces. The stability deficit increases with increasing height of the anterior intervertebral space, which for some warrants the adjunction of an intersomatic arthrodesis in addition to the posterolateral graft. Few studies have been devoted to the impact of disc height on the outcome of posterolateral fusion. The purpose of this work was to investigate the spinal segment immobilized by the posterolateral fusion: height of the anterior intervertebral space, the clinical and radiographic impact of changes in disc height, and the short- and long-term impact of disc height measured preoperatively on clinical and radiographic outcome. In order to obtain a homogeneous group of patients, the series was limited to patients undergoing posterolateral arthrodesis for degenerative spondylolisthesis, in combination with radicular release. This was a retrospective analysis of a consecutive series of 66 patients with mean 52 months follow-up (range 3-63 months). A dedicated self-administered questionnaire was used to collect data on pre- and postoperative function, the SF-36 quality of life score, and patient satisfaction. Pre- and postoperative (early, one year, last follow-up) radiographic data were recorded: olisthesic level, disc height, intervertebral angle, intervertebral mobility (angular, anteroposterior), and global measures of sagittal balance (thoracic kyphosis, lumbar lordosis, T9 sagittal tilt, pelvic version, pelvic incidence, sacral slope). SpineView was used for all measures. Univariate analysis searched for correlations between variation in disc height and early postoperative function and quality of fusion at last follow-up. Multivariate analysis was applied to the following preoperative parameters: intervertebral angle, disc height, intervertebral mobility, sagittal balance parameters, use of osteosynthesis or not. At the olisthesic

  5. Clinico-pathological factors influencing surgical outcome in drug resistant epilepsy secondary to mesial temporal sclerosis.

    Science.gov (United States)

    Savitr Sastri, B V; Arivazhagan, A; Sinha, Sanjib; Mahadevan, Anita; Bharath, R D; Saini, J; Jamuna, R; Kumar, J Keshav; Rao, S L; Chandramouli, B A; Shankar, S K; Satishchandra, P

    2014-05-15

    Mesial temporal sclerosis (MTS) is the most common cause of drug resistant epilepsy amenable for surgical treatment and seizure control. This study analyzed the outcome of patients with MTS following anterior temporal lobectomy and amygdalohippocampectomy (ATL-AH) over 10 years and correlated the electrophysiological and radiological factors with the post operative seizure outcome. Eighty seven patients were included in the study. Sixty seven (77.2%) patients had an Engel Class 1 outcome, 9 (11.4%) had Class 2 outcome. Engel's class 1 outcome was achieved in 89.9% at 1 year, while it reduced slightly to 81.9% at 2 years and 76.2% at 5 year follow up. Seventy seven (88.5%) patients had evidence of hippocampal sclerosis on histopathology. Dual pathology was observed in 19 of 77 specimens with hippocampal sclerosis, but did not influence the outcome. Factors associated with an unfavorable outcome included male gender (p=0.04), and a higher frequency of pre-operative seizures (p=0.005), whereas the presence of febrile seizures (p=0.048) and loss of hippocampal neurons in CA4 region on histopathology (p=0.040) were associated with favorable outcome. The effect of CA4 loss on outcome is probably influenced by neuronal loss in other subfields as well since isolated CA4 loss was rare. Abnormal post operative EEG at the end of 1 week was found to be a significant factor predicting unfavorable outcome (p=0.005). On multivariate analysis, the pre-operative seizure frequency was the only significant factor affecting outcome. The present study observed excellent seizure free outcome in a carefully selected cohort of patients with MTS with refractory epilepsy. The presence of dual pathology did not influence the outcome. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. The influence of poly(acrylic) acid number average molecular weight and concentration in solution on the compressive fracture strength and modulus of a glass-ionomer restorative.

    LENUS (Irish Health Repository)

    Dowling, Adam H

    2011-06-01

    The aim was to investigate the influence of number average molecular weight and concentration of the poly(acrylic) acid (PAA) liquid constituent of a GI restorative on the compressive fracture strength (σ) and modulus (E).

  7. Can a soda-lime glass be used to demonstrate how patterns of strength dependence are influenced by pre-cementation and resin-cementation variables?

    LENUS (Irish Health Repository)

    Hooi, Paul

    2013-01-01

    To determine how the variability in biaxial flexure strength of a soda-lime glass analogue for a PLV and DBC material was influenced by precementation operative variables and following resin-cement coating.

  8. Framing matters: contextual influences on interracial interaction outcomes.

    Science.gov (United States)

    Babbitt, Laura G; Sommers, Samuel R

    2011-09-01

    Previous studies indicate that interracial interactions frequently have negative outcomes but have typically focused on social contexts. The current studies examined the effect of manipulating interaction context. In Study 1, Black and White participants worked together with instructions that created either a social focus or a task focus. With a task focus, interracial pairs were more consistently synchronized, Black participants showed less executive function depletion, and White participants generally showed reduced implicit bias. Follow-up studies suggested that prejudice concerns help explain these findings: White participants reported fewer concerns about appearing prejudiced when they imagined an interracial interaction with a task focus rather than a social focus (Study 2a), and Black participants reported less vigilance against prejudice in an imagined interracial interaction with a task focus rather than a social focus (Study 2b). Taken together, these studies illustrate the importance of interaction context for the experiences of both Blacks and Whites.

  9. Influence of cold deformation and annealing on hydrogen embrittlement of cold hardening bainitic steel for high strength bolts

    Energy Technology Data Exchange (ETDEWEB)

    Hui, Weijun, E-mail: wjhui@bjtu.edu.cn [School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Zhang, Yongjian; Zhao, Xiaoli; Shao, Chengwei [School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Wang, Kaizhong; Sun, Wei; Yu, Tongren [Technical Center, Maanshan Iron & Steel Co., Ltd., Maanshan 243002, Anhui (China)

    2016-04-26

    The influence of cold drawing and annealing on hydrogen embrittlement (HE) of newly developed cold hardening bainitic steel was investigated by using slow strain rate testing (SSRT) and thermal desorption spectrometry (TDS), for ensuring safety performance of 10.9 class high strength bolts made of this kind of steel against HE under service environments. Hydrogen was introduced into the specimen by electrochemical charging. TDS analysis shows that the hydrogen-charged cold drawn specimen exhibits an additional low-temperature hydrogen desorption peak besides the original high-temperature desorption peak of the as-rolled specimen, causing remarkable increase of absorbed hydrogen content. It is found that cold drawing significantly enhances the susceptibility to HE, which is mainly attributed to remarkable increase of diffusible hydrogen absorption, the occurrence of strain-induced martensite as well as the increase of strength level. Annealing after cold deformation is an effective way to improve HE resistance and this improvement strongly depends on annealing temperature, i.e. HE susceptibility decreases slightly with increasing annealing temperature up to 200 °C and then decreases significantly with further increasing annealing temperature. This phenomenon is explained by the release of hydrogen, the recovery of cold worked microstructure and the decrease of strength with increasing annealing temperature.

  10. The influence of flame hardening process to aluminum 7075 series on the mechanical strength and micro structure

    Science.gov (United States)

    Koin, Sudibtia Titio; Triyono, Teguh; Surojo, Eko

    2018-02-01

    The 7075 series alloys are heat treatable wrought aluminum alloys based on the Al-Zn-Mg(-Cu) system. They are widely used in high-performance structural aerospace and transportation applications. Apart from compositional, casting and thermo-mechanical processing effects, the balance of properties is also significantly influenced by the way in which the materials are heat-treated. This paper describes the effect of flame hardening process to aluminum 7075 series on the increasing hardness, tensile strength, and evolution of microstructure. A test specimen had made by machining process and flame heating. Temperature of solution heat treatment is varied on 350 °C, 400 °C, 450 °C and 500 °C. After that process a test specimen would be quenched at nitrate-nitrite liquid during 45 minutes and artificial aging at 120°C until two days. The testing specimen consist of hardness and tensile strength according to ASTM. The result showed that specimen had precipitation on microstructure lead to an increase in aluminum properties. On the temperature 450°C solution heat treatment, the aluminum properties reached the highest value, namely, hardness of 129 HVN and tensile strength 570 MPa.

  11. Influence of Graphene Nanosheets on Rheology, Microstructure, Strength Development and Self-Sensing Properties of Cement Based Composites

    Directory of Open Access Journals (Sweden)

    Sardar Kashif Ur Rehman

    2018-03-01

    Full Text Available In this research, Graphene oxide (GO, prepared by modified hammer method, is characterized using X-ray Diffraction (XRD, Fourier Transform Infrared (FT-IR Spectrometry and Raman spectra. The dispersion efficiency of GO in aqueous solution is examined by Ultraviolet–visible spectroscopy and it is found that GO sheets are well dispersed. Thereafter, rheological properties, flow diameter, hardened density, compressive strength and electrical properties of GO based cement composite are investigated by incorporating 0.03% GO in cement matrix. The reasons for improvement in strength are also discussed. Rheological results confirm that GO influenced the flow behavior and enhanced the viscosity of the cement based system. From XRD and Thermogravimetric Analysis (TGA results, it is found that more hydration occurred when GO was incorporated in cement based composite. The GO based cement composite improves the compressive strength and density of mortar by 27% and 1.43%, respectively. Electrical properties results showed that GO–cement based composite possesses self-sensing characteristics. Hence, GO is a potential nano-reinforcement candidate and can be used as self-sensing sustainable construction material.

  12. Influence of austenization temperature on microstructure and mechanical properties of a new ultra-high strength low alloyed steel

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Ya-Ya; Xu, Chi; Su, Xiang; Sun, Yu-Lin; Pan, Xi; Cao, Yue-De; Chen, Guang [Nanjing Univ. of Science and Technology, Nanjing (China). Engineering Research Center of Materials Behavior and Design

    2017-07-01

    The effects of austenization temperature on the microstructures and mechanical properties of a newly designed ultra-high strength low alloy martensitic steel were systematically studied. The microstructures of the martensitic steels which were quenched from different temperatures between 860 and 980 C were investigated by transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) and discussed. The results showed that the martensite laths were found to coarsen slowly and the carbide precipitates dissolved gradually with increasing austenization temperature. As the austenization temperature increased from 860 to 980 C, the volume of retained austenite and the numerical ratio of high angle grain boundaries (HAGBs) were observed to increase while the numerical ratio of low angle grain boundaries (LAGBs) decreased. Rockwell C hardness (HRC), tensile strength and yield strength increased at first and then decreased, while impact toughness was greatly improved with increasing austenization temperature. The fracture mechanism was brittle fracture when austenitized at low temperatures, while it was ductile fracture when austenitized at high temperatures. The mechanical properties were significantly influenced by the formation of retained austenite, the dissolution of carbides, and the numerical ratio of HAGBs and LAGBs.

  13. Influence of casting defects on fatigue strength of an investment cast Ti-6Al-4V alloy

    Directory of Open Access Journals (Sweden)

    Léopold Gaëlle

    2014-06-01

    Full Text Available The influence of casting defects on fatigue strength of an investment cast Ti-6Al-4V alloy is investigated. The most common of these defects are: pinhole, linear defect and inclusion. Each of them is currently defined by its size, morphology and position from the surface but is different from each other for a same type. An experimental campaign is defined with different types of defect. The first part of the campaign is focused on the influence of an artificial and spherical defect, considering two different surface conditions. It is shown that fatigue behaviour of this alloy is very sensitive to the surface condition of this artificial defect despite stress concentrations at the tip of the defect. The second part of the campaign is focused on casting defects: reduction of fatigue life is quantified and it is shown that an electro-discharge machined defect cannot be representative of pinhole.

  14. Outcomes of a Character Strengths-Based Intervention on Self-Esteem and Self-Efficacy of Psychiatrically Hospitalized Youths.

    Science.gov (United States)

    Toback, Rebecca L; Graham-Bermann, Sandra A; Patel, Paresh D

    2016-05-01

    Mental health treatment approaches based on character strengths can be used to complement the traditional focus on functional impairment. The study tested use of a character strengths-based intervention to enhance the self-esteem and self-efficacy of psychiatrically hospitalized youths. Eighty-one hospitalized adolescents were randomly assigned to intervention or comparison groups. The intervention used the Values in Action Inventory of Strengths for Youth to discover character strengths and incorporate them into coping skills. Self-efficacy and self-esteem were measured at baseline, postintervention, two weeks, and three months. Self-esteem and self-efficacy initially increased in both groups, but only the intervention group showed sustained improvement. The intervention was associated with increased self-efficacy at two weeks and increased self-efficacy and self-esteem at three months. A brief, easily administered character strengths-based intervention may be an adjunctive tool in the treatment of psychiatrically hospitalized youths.

  15. Influence of nanoparticles on color stability, microhardness, and flexural strength of acrylic resins specific for ocular prosthesis

    Directory of Open Access Journals (Sweden)

    Andreotti AM

    2014-12-01

    Full Text Available Agda Marobo Andreotti, Marcelo Coelho Goiato, Amália Moreno, Adhara Smith Nobrega, Aldiéris Alves Pesqueira, Daniela Micheline dos Santos Araçatuba Dental School, São Paulo State University, Araçatuba, São Paulo, Brazil Abstract: The aim of this study was to assess the effect of adding nanoparticles to N1 acrylic resin intended for artificial sclera, in terms of the color stability, microhardness, and flexural strength of the resin. Three hundred samples of N1 acrylic resin were used: 100 samples for color stability and microhardness tests (each test was performed on the opposite side of each sample, and 200 samples for flexural strength testing (100 samples before and after 1,008 hours of accelerated aging. Samples for each test were separated into ten groups (n=10, ie, without nanoparticles (control group or with nanoparticles of zinc oxide, titanium dioxide (TiO2, and barium sulfate at weight concentrations of 1%, 2%, and 2.5% (nanoparticle groups. Data were subjected to statistical analysis with nested analysis of variance and Tukey’s test (P<0.05 significance level. Among the nanoparticle groups, the TiO2 groups showed better color stability at all concentrations. Microhardness values increased after artificial aging, except for the control and zinc oxide groups. After aging, the 1%–2% TiO2 groups had significantly higher microhardness values compared with the other nanoparticle groups. Before aging, there was a significant difference in flexural strength between the control and nanoparticle groups. After aging, the control and TiO2 groups, regardless of concentration, showed the lowest flexural strength values. Incorporation of nanoparticles directly influenced the acrylic resin properties, with TiO2 being the most influential nanoparticle in terms of the evaluated properties. Keywords: acrylic resins, eye, artificial, color, hardness, nanoparticles

  16. Influence of atmospheric pressure low-temperature plasma treatment on the shear bond strength between zirconia and resin cement.

    Science.gov (United States)

    Ito, Yuki; Okawa, Takahisa; Fukumoto, Takahiro; Tsurumi, Akiko; Tatsuta, Mitsuhiro; Fujii, Takamasa; Tanaka, Junko; Tanaka, Masahiro

    2016-10-01

    Zirconia exhibits excellent strength and high biocompatibility in technological applications and it is has therefore been investigated for clinical applications and research. Before setting prostheses, a crown prosthesis inner surface is sandblasted with alumina to remove contaminants and form small cavities. This alumina sandblasting causes stress-induced phase transition of zirconia. Atmospheric-pressure low-temperature plasma has been applied in the dental industry, particularly for adhesives, as a surface treatment to activate the surface energy and remove contaminants. The purpose of this study was to examine the influence of atmospheric-pressure low-temperature plasma treatment on the shear bond strength between zirconia and adhesive resin cement. The surface treatment method was classified into three groups: untreated (Cont group), alumina sandblast treatment (Sb group), and atmospheric-pressure low-temperature plasma treatment (Ps group). Adhesive resin cement was applied to stainless steel and bonded to zirconia. Shear adhesion tests were performed after complete hardening of the cement. Multiple comparisons were performed using a one-way analysis of variance and the Bonferroni method. X-ray diffractometry was used to examine the change in zirconia crystal structure. Statistically significant differences were noted between the control and Sb groups and between the control and Ps groups. In contrast, no statistically significant differences were noted for the Ps and Sb bond strength. Atmospheric-pressure low-temperature plasma treatment did not affect the zirconia crystal structure. Atmospheric-pressure low-temperature plasma treatment improves the bonding strength of adhesive resin cement as effectively as alumina sandblasting, and does not alter the zirconia crystal structure. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  17. Influence of glass particle size of resin cements on bonding to glass ceramic: SEM and bond strength evaluation.

    Science.gov (United States)

    Valentini, Fernanda; Moraes, Rafael R; Pereira-Cenci, Tatiana; Boscato, Noéli

    2014-05-01

    This study investigated the effect of the filler particle size (micron or submicron) of experimental resin cements on the microtensile bond strength to a glass-ceramic pretreated with hydrofluoric acid (HFA) etching or alumina airborne-particle abrasion (AA). Cements were obtained from a Bis-GMA/TEGDMA mixture filled with 60 mass% micron-sized (1 ± 0.2 µm) or submicron-sized (180 ± 30 µm) Ba-Si-Al glass particles. Ceramic blocks (PM9; VITA) were treated with 10% HFA for 60 s or AA for 15 s. Silane and adhesive were applied. Ceramic blocks were bonded to resin composite blocks (Z250; 3M ESPE) using one of the cements. Bonded specimens were sectioned into beams (n = 20/group) and subjected to microtensile bond strength tests. Data were analyzed using ANOVA and Student-Newman-Keuls' tests (5%). Failure modes were classified under magnification. Morphologies of the treated ceramic surfaces and bonded interfaces were evaluated by scanning electron microscopy. The HFA-submicron group had lower bond strengths than the other groups. All AA-submicron specimens debonded prematurely. Mixed failures were predominant for HFA groups, whereas interfacial failures predominated for AA groups. SEM revealed a honeycomb-like aspect in the HFA-treated ceramic, whereas the AA-treated groups showed an irregular retentive pattern. Continuity of cement infiltration along the bonded interface was more uniform for HFA-treated compared to AA-treated specimens. Cracks toward the bulk of the ceramic were observed in AA-treated specimens. Particle size significantly influenced the ceramic bond strength, whereas surface treatment had a minor effect. Copyright © 2014 Wiley Periodicals, Inc.

  18. The influence of silane evaporation procedures on microtensile bond strength between a dental ceramic and a resin cement

    Directory of Open Access Journals (Sweden)

    Pereira Carolina

    2010-01-01

    Full Text Available Aim: To assess the influence of silane evaporation procedures on bond strength between a dental ceramic and a chemically activated resin cement. Materials and Methods: Eighteen blocks (6 mm Χ 14 mm Χ 14 mm of ceramic IPS Empress 2 were cemented (C and B to composite resin (InTen-S blocks using a chemical adhesive system (Lok. Six groups were analyzed, each with three blocks divided according to ceramic surface treatment: two control groups (no treatment, NT; 10% hydrofluoric acid plus silane Monobond-S dried at room temperature, HFS; the other four groups comprised different evaporation patterns (silane rinsed and dried at room temperature, SRT; silane rinsed in boiling water and dried as before, SBRT; silane rinsed with boiling water and heat dried at 50°C, SBH; silane dried at 50 ± 5°C, rinsed in boiling water and dried at room temperature, SHBRT. The cemented blocks were sectioned to obtain specimens for microtensile test 7 days after cementation and were stored in water for 30 days prior to testing. Fracture patterns were analyzed by optical and scanning electron microscopy. Statistics and Results: All blocks of NT debonded during sectioning. One way ANOVA tests showed higher bond strengths for HFS than for the other groups. SBRT and SBH were statistically similar, with higher bond strengths than SRT and SHBRT. Failures were 100% adhesive in SRT and SHBRT. Cohesive failures within the "adhesive zone" were detected in HFS (30%, SBRT (24% and SBH (40%. Conclusion: Silane treatment enhanced bond strength in all conditions evaluated, showing best results with HF etching.

  19. Influence of Carbide Modifications on the Mechanical Properties of Ultra-High-Strength Stainless Steels

    Science.gov (United States)

    Seo, Joo-Young; Park, Soo-Keun; Kwon, Hoon; Cho, Ki-Sub

    2017-10-01

    The mechanical properties of ultra-high-strength secondary hardened stainless steels with varying Co, V, and C contents have been studied. A reduced-Co alloy based on the chemical composition of Ferrium S53 was made by increasing the V and C content. This changed the M2C-strengthened microstructure to a MC plus M2C-strengthened microstructure, and no deteriorative effects were observed for peak-aged and over-aged samples despite the large reduction in Co content from 14 to 7 wt pct. The mechanical properties according to alloying modification were associated with carbide precipitation kinetics, which was clearly outlined by combining analytical tools including small-angle neutron scattering (SANS) as well as an analytical TEM with computational simulation.

  20. Influence of association of "EVA-NBR" on indirect tensile strength of modified bituminous concrete

    Science.gov (United States)

    Chinoun, M.; Soudani, K.; Haddadi, S.

    2016-04-01

    The aim of this work is to contribute to the improvement of the mechanical properties of bituminous concrete by modification of bituminous concrete. In this study, we present the results of the indirect tensile strength "ITS" of modified bituminous concrete by the combination of two modifiers, one is a plastomer EVA (Ethylene Vinyl Acetate) and the other is a industrial waste from the shoe soles grinding NBR (Nitrile Butadiene Rubber) as crumb rubber. To modify the bitumen a wet process was used. The results show that the modification of bitumen by EVA-NBR combination increases their resistance to the indirect traction "ITS" compared to the bituminous concrete control. The mixture of 5% [50% EVA+ 50% NBR] is given the best result among the other associations.

  1. The influence of training status on the drop in muscle strength after acute exercise

    DEFF Research Database (Denmark)

    Pingel, Jessica; Moerch, L; Kjaer, M

    2009-01-01

    to running exercise immediately after immobilization, the muscle strength of the triceps-surae muscles dropped even further, but just in the immobilized leg (41%; P importance of determining the muscle endurance when evaluating the effect of immobilization on muscle......Skeletal muscles fatigue after exercise, and reductions in maximal force appear. A difference in training status between the legs was introduced by unilateral immobilization of the calf muscles for 2 weeks in young men, who were randomly assigned to two groups, either a RUN group (n = 8......) that was exposed to prolonged exercise (1-h running: individual pace) or a REST group (n = 12) that did no exercise after immobilization. Cross-sectional area (CSA) of the triceps-surae muscles was calculated by magnetic resonance imaging (MRI), and maximal voluntary contraction (MVC) force of the plantar flexors...

  2. Viscoelastic behaviour and static fatigue strength of glass/epoxy composites. Influence of hydrothermal ageing

    International Nuclear Information System (INIS)

    Chateauminois, Antoine

    1991-01-01

    As ageing strength of composites appears to be one of the main criteria of their durability, this research thesis addresses the hydrothermal ageing of unidirectional glass/epoxy composites used for load-bearing structures. After having presented the used materials (epoxy matrix, reinforcement, composite elaboration), the author present the experimental techniques: viscoelastic analysis, three-point bend static fatigue test, coupled gravimetry and calorimetry, and thermogravimetry. In the next parts, the author reports the study of water sorption processes (bibliographical study, experimental study of water sorption kinetics, experimental study of interfacial diffusion within the composite), the study of plasticizing phenomena (methodology of study of plasticizing phenomena, study of the modifications of the linear viscoelastic behaviour in the glass transition region and at room temperature, relationship between plasticizing and fatigue mechanical properties by fracture studies), and the study of irreversible degradation and damage mechanisms

  3. Influence of Etching Protocol and Silane Treatment with a Universal Adhesive on Lithium Disilicate Bond Strength.

    Science.gov (United States)

    Kalavacharla, V K; Lawson, N C; Ramp, L C; Burgess, J O

    2015-01-01

    To measure the effects of hydrofluoric acid (HF) etching and silane prior to the application of a universal adhesive on the bond strength between lithium disilicate and a resin. Sixty blocks of lithium disilicate (e.max CAD, Ivoclar Vivadent) were sectioned into coupons and polished. Specimens were divided into six groups (n=10) based on surface pretreatments, as follows: 1) no treatment (control); 2) 5% HF etch for 20 seconds (5HF); 3) 9.5% HF etch for 60 seconds (9.5HF); 4) silane with no HF (S); 5) 5% HF for 20 seconds + silane (5HFS); and 6) 9.5% HF for 60 seconds + silane (9.5HFS). All etching was followed by rinsing, and all silane was applied in one coat for 20 seconds and then dried. The universal adhesive (Scotchbond Universal, 3M ESPE) was applied onto the pretreated ceramic surface, air thinned, and light cured for 10 seconds. A 1.5-mm-diameter plastic tube filled with Z100 composite (3M ESPE) was applied over the bonded ceramic surface and light cured for 20 seconds on all four sides. The specimens were thermocycled for 10,000 cycles (5°C-50°C/15 s dwell time). Specimens were loaded until failure using a universal testing machine at a crosshead speed of 1 mm/min. The peak failure load was used to calculate the shear bond strength. Scanning electron microscopy images were taken of representative e.max specimens from each group. A two-way analysis of variance (ANOVA) determined that there were significant differences between HF etching, silane treatment, and the interaction between HF and silane treatment (puniversal adhesive.

  4. Influence of different crosshead speeds on diametral tensile strength of a methacrylate based resin composite: An in-vitro study.

    Science.gov (United States)

    Sood, Anubhav; Ramarao, Sathyanarayanan; Carounanidy, Usha

    2015-01-01

    The aim was to evaluate the influence of different crosshead speeds on diametral tensile strength (DTS) of a resin composite material (Tetric N-Ceram). The DTS of Tetric N-Ceram was evaluated using four different crosshead speeds 0.5 mm/min (DTS 1), 1 mm/min (DTS 2), 5 mm/min (DTS 3), 10 mm/min (DTS 4). A total of 48 specimens were prepared and divided into four subgroups with 12 specimens in each group. Specimens were made using stainless steel split custom molds of dimensions 6 mm diameter and 3 mm height. The specimens were stored in distilled water at room temperature for 24 h. Universal testing machine was used and DTS values were calculated in MPa. Analysis of variance was used to compare the four groups. Higher mean DTS value was recorded in DTS 2 followed by DTS 4, DTS 1, and DTS 3, respectively. However, the difference in mean tensile strength between the groups was not statistically significant (P > 0.05). The crosshead speed variation between 0.5 and 10 mm/min does not seem to influence the DTS of a resin composite.

  5. Influence of method and period of storage on the microtensile bond strength of indirect composite resin restorations to dentine

    Directory of Open Access Journals (Sweden)

    Fernanda Ribeiro Santana

    2008-12-01

    Full Text Available This study evaluated the influence of the method and period of storage on the adhesive bond strength of indirect composite resin to bovine dentin. Ninety bovine incisors were stored in three different solutions: 0.2% thymol, 10% formalin, and 0.2% sodium azide, during 3 periods of storage: 7 days, 30 days and 6 months, resulting in 9 groups (n = 10. The roots were cut off and the buccal surface was ground with #600-grit silicon carbide paper. The surface was conditioned with 37% phosphoric acid for 15 s and a composite resin restoration (TPH Spectrum was fixed using a one-bottle adhesive system (Adper Single Bond and a dual-cured resinous cement (Rely X ARC under a load of 500 g for 5 minutes. The samples were serially cut perpendicular to the bonded interface to obtain slices of 1.2 mm in thickness. Each slab was trimmed with a cylindrical diamond bur resulting in an hourglass shape with a cross-sectional area of approximately 1 mm². The microtensile bond strength (μTBS testing was performed in a testing machine (EMIC 2000 DL at a 0.5 mm/minute crosshead-speed until failure. After fracture, the specimens were examined under SEM to analyze the mode of fracture. μTBS Means were expressed in MPa and the data were analyzed by two-way ANOVA (3X3 and the Tukey test (α = 0.05. The storage times of 7 and 30 days produced no significant difference irrespective of the solution type. The formalin and thymol solutions, however, did have a negative influence on bond strength when the teeth were stored for 6 months.

  6. Influence of acute stress on decision outcomes and heuristics.

    Science.gov (United States)

    Hepler, Teri J; Kovacs, Attila J

    2017-03-01

    The purpose of this study was to examine the take-the-first (TTF) heuristic and decision outcomes in sports under conditions of no, mental, and physical stress. Participants (N.=68) performed 8 video decision-making trials under each of 3 stress conditions: no stress (counting backwards), mental stress (mental serial subtraction), and physical stress (running on treadmill at 13 RPE). Prior to each decision-making trial, participants were exposed to 30 seconds of stress. The decision-making task required participants to watch a video depicting an offensive situation in basketball and then decide what the player with the ball should do next. No differences were found between the 3 stress conditions on TTF frequency, number of options generated, quality of first generated option, or final decision quality. However, participants performing under conditions of no stress and physical stress generated their first option and made their final decision faster than they did when making decisions under mental stress. Overall, results suggest that mental stress impairs decision speed and that TTF is an ecologically rationale heuristic in dynamic, time-pressured situations.

  7. [Influence of anesthesia procedure on malignant tumor outcome].

    Science.gov (United States)

    Fukui, K; Werner, C; Pestel, G

    2012-03-01

    Malignant tumors are the second major cause of death in Germany. The essential therapy of operable cancer is surgical removal of primary tumors combined with adjuvant therapy. However, several consequences of surgery may promote metastasis, such as shedding of tumor cells into the circulation, decrease in tumor-induced antiangiogenesis factors, excessive release of growth factors for wound healing and suppression of immunity induced by surgical stress. In the last decade it has become clear that cell-mediated immunity controls the development of metastasis. Various perioperative factors, such as surgical stress, certain anesthetic and analgesic drugs and pain can suppress the patients' immune system perioperatively. On the other hand, by modifications of the anesthesia technique (e.g. regional anesthesia) and perioperative management to minimize immunosuppression, anesthesiologists can play a considerable role for a better outcome in patients having malignant tumors. Sufficient clinical evidence is not yet available to prove or disprove the hypothesis that anesthesia practice can improve cancer prognosis. Despite difficulties in study design, several prospective randomized trials are currently running and the results are awaited to elucidate this topic.

  8. The Influence of Distractor Strength and Response Order on MCQ Responding

    Science.gov (United States)

    Kiat, John Emmanuel; Ong, Ai Rene; Ganesan, Asha

    2018-01-01

    Multiple-choice questions (MCQs) play a key role in standardised testing and in-class assessment. Research into the influence of within-item response order on MCQ characteristics has been mixed. While some researchers have shown preferential selection of response options presented earlier in the answer list, others have failed to replicate these…

  9. Heat denaturation of soy glycinin : Influence of pH and ionic strength on molecular structure

    NARCIS (Netherlands)

    Lakemond, C.M.M.; Jongh, de H.H.J.; Hessing, M.; Gruppen, H.; Voragen, A.G.J.

    2000-01-01

    The 7S/11S glycinin equilibrium as found in Lakemond et al. (J. Agric. Food Chem. 2000, 48, xxxx-xxxx) at ambient temperatures influences heat denaturation. It is found that the 7S form of glycinin denatures at a lower temperature than the 11S form, as demonstrated by a combination of calorimetric

  10. The influence of different bracket base surfaces on tensile and shear bond strength

    NARCIS (Netherlands)

    Algera, T.J.; Kleverlaan, C.J.; Prahl-Andersen, B.; Feilzer, A.J.

    2008-01-01

    Fracture of the bracket-cement-enamel system usually takes place between the bracket and the cement. Especially for glass ionomer-based materials, it is helpful if this part of the system can be improved. The aim of this in vitro study was to investigate the influence of different bracket base

  11. Does Age Influence Cardiac Resynchronization Therapy Use and Outcome?

    Science.gov (United States)

    Heidenreich, Paul A; Tsai, Vivian; Bao, Haikun; Curtis, Jeptha; Goldstein, Mary; Curtis, Lesley; Hernandez, Adrian; Peterson, Pamela; Turakhia, Mintu P; Masoudi, Frederick A

    2015-06-01

    This study sought to describe the use of CRT-D and its association with survival for older patients. Many patients who receive cardiac resynchronization therapy with defibrillator (CRT-D) in practice are older than those included in clinical trials. We identified patients undergoing ICD implantation in the National Cardiovascular Disease Registry (NCDR) ICD registry from 2006 to 2009, who also met clinical trial criteria for CRT, including left ventricular ejection fraction (LVEF) ≤35%, QRS ≥120 ms, and New York Heart Association (NYHA) functional class III or IV. NCDR registry data were linked to the social security death index to determine the primary outcome of time to death from any cause. We identified 70,854 patients from 1,187 facilities who met prior trial criteria for CRT-D. The mean age of the 58,147 patients receiving CRT-D was 69.4 years with 6.4% of patients age 85 or older. CRT use was 80% or higher among candidates in all age groups. Follow-up was available for 42,285 patients age ≥65 years at 12 months. Receipt of CRT-D was associated with better survival at 1 year (82.1% vs. 77.1%, respectively) and 4 years (54.0% vs. 46.2% , respectively) than in those receiving only an ICD (p different for different age groups (p = 0.86 for interaction). More than 80% of older patients undergoing ICD implantation who were candidates for a CRT-D received the combined device. Mortality in older patients undergoing ICD implantation was high but was lower for those receiving CRT-D. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  12. Factors influencing the use of outcome measures in physical therapy practice.

    Science.gov (United States)

    Wedge, Frances M; Braswell-Christy, Jennifer; Brown, Cynthia J; Foley, Kathleen T; Graham, Cecilia; Shaw, Sharon

    2012-02-01

    Use of outcome measures in physical therapy practice is central to evaluating the effectiveness of treatment interventions, providing accountability and addressing quality of physical therapy programs. There is limited discussion on barriers and facilitators to using outcome measures in physical therapy practice. The purpose of this study was to identify factors that influence a physical therapist when deciding to use outcome measures in clinical practice. Participants were 21 physical therapists, seven each from skilled nursing facilities, outpatient clinics, and inpatient rehabilitation facilities. A grounded theory approach was used for interview and data collection. Common themes were determined from the data and a theory developed to explain the rationale behind physical therapists' decisions to use or not use outcome measures in clinical practice. Three overlapping themes related to (1) concepts of time, (2) knowledge, and (3) facility culture were indentified as factors influencing the use of outcome measures. A fourth encompassing theme, professionalism, identified the value placed on the use of outcome measures in practice. Data revealed that therapists require more information on the outcome measures available, and this information needs to be easily accessible within the workplace. Therapists value information generated by using outcome measures in the clinical setting, but need information on what measures are available and psychometric properties. Information must be easily accessible and measures easy to use. Newer graduates and recent learners have a foundation in the use of outcome measures, but more needs to be done in the clinic and through continuing education to promote increased use and understanding.

  13. The influence of curing time on the shear strength of fluidized fly ash

    Directory of Open Access Journals (Sweden)

    Gruchot Andrzej

    2015-06-01

    Full Text Available The paper presents results of research on the influence of compaction and air and water curing on angle of internal friction and cohesion of fluidized fly ash from “Połaniec” Power Plant. It was stated that the increase in compaction resulted in an insignificant increase of the angle of internal friction and a quite significant increase of cohesion. While the type and time of curing had a great influence on the angle of internal friction and cohesion. The highest values of angle of internal friction were obtained in the air curing, and the lowest in the water curing whereas in case of cohesion there was an inverse relation. The rise of curing time resulted in largely increased cohesion and small changes of angle of internal friction.

  14. Predicting the drying shrinkage behavior of high strength portland cement mortar under the combined influence of fine aggregate and steel micro fiber

    International Nuclear Information System (INIS)

    Li, Zhengqi

    2017-01-01

    The workability, 28-day compressive strength and free drying shrinkage of a very high strength (121-142 MPa) steel micro fiber reinforced portland cement mortar were studied under a combined influence of fine aggregate content and fiber content. The test results showed that an increase in the fine aggregate content resulted in decreases in the workability, 28-day compressive strength and drying shrinkage of mortar at a fixed fiber content. An increase in the fiber content resulted in decreases in the workability and drying shrinkage of mortar, but an increase in the 28-day compressive strength of mortar at a fixed fine aggregate content. The modified Gardner model most accurately predicted the drying shrinkage development of the high strength mortars, followed by the Ross model and the ACI 209R-92 model. The Gardner model gave the least accurate prediction for it was developed based on a database of normal strength concrete. [es

  15. Predicting the drying shrinkage behavior of high strength portland cement mortar under the combined influence of fine aggregate and steel micro fiber

    Directory of Open Access Journals (Sweden)

    Zhengqi Li

    2017-03-01

    Full Text Available The workability, 28-day compressive strength and free drying shrinkage of a very high strength (121-142 MPa steel micro fiber reinforced portland cement mortar were studied under a combined influence of fine aggregate content and fiber content. The test results showed that an increase in the fine aggregate content resulted in decreases in the workability, 28-day compressive strength and drying shrinkage of mortar at a fixed fiber content. An increase in the fiber content resulted in decreases in the workability and drying shrinkage of mortar, but an increase in the 28-day compressive strength of mortar at a fixed fine aggregate content. The modified Gardner model most accurately predicted the drying shrinkage development of the high strength mortars, followed by the Ross model and the ACI 209R-92 model. The Gardner model gave the least accurate prediction for it was developed based on a database of normal strength concrete.

  16. A Research Agenda for Evaluating Strength of Internal Preferences and External Influences in Consumer Smartphone Switching

    OpenAIRE

    Nykänen, Jussi Ilmari; Tuunainen, Virpi Kristiina; Tuunanen, Tuure

    2015-01-01

    This article proposes a research agenda to study what causes consumers to switch smartphone manufacturer and operating system brands. International consumer survey is planned for data collection and structural equation modeling method will be used to extrapolate whether internal preferences play a larger role than external influences in consumers’ switching behavior. The effects are expected to be moderated by behavioral control, subjective uncertainty and prior switching ex...

  17. Strength Training Parallel with Plyometric and Cross training Influences on Speed Endurance

    OpenAIRE

    C.C.Chandra Obul Reddy; Dr. K. Rama Subba Reddy

    2017-01-01

    The purpose of the study was to find out the influence of weight training parallel with plyometric and cross training on speed endurance. To achieve this purpose of the study, forty-five men students studying CSSR & SRRM Degree College, Kamalapuram, YSR (D), Andhra Pradesh, India were randomly selected as subjects during the year 2015-2016. They were divided into three equal groups of fifteen subjects each. Group I underwent weight training parallel with plyometric training for three sessions...

  18. Influence of relative density on the cyclic shear strength of sands

    Directory of Open Access Journals (Sweden)

    Arab A.

    2018-01-01

    Full Text Available This paper presents a laboratory study of the influence of relative density on the liquefaction potential of a soil. The study is based on undrained triaxial tests that were performed on samples with relative density Id = 0.15, 0.5 and 0.65. The article is composed of three parts. First, we present the materials and characteristics of the studied sands. the second part deals with the procedure and the device used. The third part studies the influence of the relative density on the liquefaction potential of the three sands (Hostun Rf, Chlef and Rass. This study also makes it possible to explore the influence of granulometry on the liquefaction potential. The results of the tests show that concordant results have been obtained which clearly show that the increase of the relative density leads to a significant improvement in the resistance to liquefaction of the sands. This effect is very significant when the initial relative density Id = 0.50 to Id = 0.65.

  19. Influence of heterogeneity on rock strength and stiffness using discrete element method and parallel bond model

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    Spyridon Liakas

    2017-08-01

    Full Text Available The particulate discrete element method (DEM can be employed to capture the response of rock, provided that appropriate bonding models are used to cement the particles to each other. Simulations of laboratory tests are important to establish the extent to which those models can capture realistic rock behaviors. Hitherto the focus in such comparison studies has either been on homogeneous specimens or use of two-dimensional (2D models. In situ rock formations are often heterogeneous, thus exploring the ability of this type of models to capture heterogeneous material behavior is important to facilitate their use in design analysis. In situ stress states are basically three-dimensional (3D, and therefore it is important to develop 3D models for this purpose. This paper revisits an earlier experimental study on heterogeneous specimens, of which the relative proportions of weaker material (siltstone and stronger, harder material (sandstone were varied in a controlled manner. Using a 3D DEM model with the parallel bond model, virtual heterogeneous specimens were created. The overall responses in terms of variations in strength and stiffness with different percentages of weaker material (siltstone were shown to agree with the experimental observations. There was also a good qualitative agreement in the failure patterns observed in the experiments and the simulations, suggesting that the DEM data enabled analysis of the initiation of localizations and micro fractures in the specimens.

  20. The Influence Of Loam Type And Cement Content On The Compressive Strength Of Rammed Earth

    Directory of Open Access Journals (Sweden)

    Narloch P. L.

    2015-03-01

    Full Text Available Currently, a worldwide dynamic rise of interest in using soil as a construction material can be observed. This trend is evident in the rapid rise of the amount of standards that deal with soil techniques. In 2012 the number of standards was larger by one third than five years prior. To create a full standardization of the rammed earth technique it is necessary to take into account the diversity of used soil and stabilizing additives. The proportion of the components, the process of element production and the research methods must also be made uniform. The article describes the results of research on the compressive strength of rammed earth samples that differed from each other with regards to the type of loam used for the mixture and the amount of the stabilizer. The stabilizer used was Portland cement CEM I 42.5R. The research and the analysis of the results were based on foreign publications, the New Zealand standard NZS 4298:1998, the American Standard NMAC14.7.4 and archival Polish Standards from the 1960’s that dealt with earth material.

  1. Tests on creep and influence of creep on strength of concrete under multiaxial stresses

    International Nuclear Information System (INIS)

    Lanig, N.; Stoeckl, S.; Kupfer, H.

    1988-12-01

    Long-time tests of three-axially loaded, sealed cylindrical specimens d = 15 cm, h = 40 cm, were carried out. The 20-cm-cube strength of the concrete was app. 45 N/mm 2 . The creep stresses were chosen in the following ranges: 0,3 ≤ σ c /β c ≤ 2,1; 0 ≤ σ r /σ l ≤ 1,0. The creep coefficients obtained were clearly depending on the multi-axial stress conditions. The creep coefficients for a t = 2 years loading were reaching app. 1 for σ l /β c = 0,3 and app. 3 for σ l /β c = 2,1, when the test evaluation was based on the initial deformations meausred after 1 minute. For σ l /β c = 2,1 the creep coefficients obtained were about 4 times as large, proceeding form calculated elastic deformations. Further evaluations concerned the Young's modulus E, Poisson's ratio μ, the bulk modulus K and the shear modulus G. The preceding permanent load leads to an increase in the Young's modulus of the concrete in longitudinal direction of the specimen up to about 4 times the value of not preloaded comparative specimens. (orig.) [de

  2. Influence of study in hee on ubiquity and strength of students’ computer gambling

    Directory of Open Access Journals (Sweden)

    M.D. Kudryavtsev

    2016-06-01

    Full Text Available Purpose: to clear up effectiveness of learning-education process for counteraction of students’ harmful passion to computer games’ ubiquity. Material: 1st - 3rd year students (main health group were the objects of the research. In total they were 952 boys and 523 girls. In 1st year students’ academic groups testing was carried out ant the beginning of academic year (October; in academic groups of 1st-3rd year students the testing was at the end of academic year (May. Results: it was found that among 1st year boy students ubiquity of computer gaming as well as time losses, connected with it are higher than among girl students. Educational process is not sufficiently effective in struggle against computer gaming. For girls, this passion is not dangerous in general. In the course of study at HEE, the strength of this passion reduces independent on sex. Conclusions: for increase of educational process’s effectiveness and improvement of students’ life quality it is necessary to consider personal features of boy students as well as to organize health related measures with the help of health related physical culture means.

  3. Analysis of factors influencing the bond strength in roll bonding processes

    Science.gov (United States)

    Khaledi, Kavan; Wulfinghoff, Stephan; Reese, Stefanie

    2018-05-01

    Cold Roll Bonding (CRB) is recognized as an industrial technique in which the metal sheets are joined together in order to produce laminate metal composites. In this technique, a metallurgical bond resulting from severe plastic deformation is formed between the rolled metallic layers. The main objective of this paper is to analyse different factors which may affect the bond formation in rolling processes. To achieve this goal, first, an interface model is employed which describes both the bonding and debonding. In this model, the bond strength evolution between the metallic layers is calculated based on the film theory of bonding. On the other hand, the debonding process is modelled by means of a bilinear cohesive zone model. In the numerical section, different scenarios are taken into account to model the roll bonding process of metal sheets. The numerical simulation includes the modelling of joining during the roll bonding process followed by debonding in a Double Cantilever Beam (DCB) peeling test. In all simulations, the metallic layers are regarded as elastoplastic materials subjected to large plastic deformations. Finally, the effects of some important factors on the bond formation are numerically investigated.

  4. Microstructural influence on fatigue properties of a high-strength spring steel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C.S.; Lee, K.A.; Li, D.M. [Pohang Univ. of Sci. and Technol. (Korea, Republic of). Center for Adv. Aerospace Mater.; Yoo, S.J.; Nam, W.J. [Technical Research Laboratory, Pohang Iron and Steel Co. Ltd, Pohang 790-785 (Korea, Republic of)

    1998-01-30

    A study has been made to investigate the fatigue properties of a high-strength spring steel in relation to the microstructural variation via different heat treatments. Rotating-bending fatigue and fatigue crack growth (FCG) tests were conducted to evaluate the fatigue properties, and a transmission electron microscope (TEM) equipped with an energy dispersive X-ray (EDX) unit was used to characterize the tempered microstructure. The results indicate that the fatigue endurance {sigma}{sub f} increases with increasing tempering temperature, reaching a maximum at 450 C, then decreases. The increase of {sigma}{sub f} is mainly attributed to the refined distribution of precipitation, together with the structural uniformity of tempered martensite. The softening of tempered martensite due to excessive precipitation accounts for the decrease of {sigma}{sub f}. By contrast, the FCG results show an insensitivity of the stage-II growth behavior to the microstructural changes for the whole range of tempering temperature tested. The insensitivity is interpreted in terms of the counterbalancing microstructure-dependent contributions to the FCG behavior. (orig.) 30 refs.

  5. Influence of chemical composition on microstructure and strength of alloy 718

    Energy Technology Data Exchange (ETDEWEB)

    Fedorova, T.; Roesler, J.; Gehrmann, B. [Technische Univ. Braunschweig (Germany); Kloewer, J. [ThyssenKrupp VDM GmbH, Werdohl (Germany)

    2010-07-01

    Alloy 718 has been used for many years due to its unique mechanical properties and good processing characteristics. However, the temperature limit for Alloy 718 is about 650 C because of the thermal instability of the main strengthening phase {gamma}''-Ni{sub 3}(Nb, Ti, Al). At high temperatures meta-stable {gamma}'' changes into stable {delta}-Ni{sub 3}Nb with large size and plate-like morphology. As a consequence of this the alloy looses its microstructural stability and strength. The basic intent of this paper is to examine the role of major and minor elements within typical specification limits for Alloy 718 with respect to (i) microstructure evolution, (ii) strengthening effects and (iii) thermal stability of {gamma}' and {gamma}''. For this purpose, thermodynamic calculations using the software THERMOCALC were performed, varying the content of Nb, Ti, Al as well as B and Zr. In addition, alloys with precisely controlled chemical composition were prepared by drop casting in a vacuum arc furnace and hot forged, so that it was possible to compare the theoretical predictions with experimental results. The microstructure evolution was studied in detail by means of scanning electron microscopy and X-ray diffraction. Furthermore, mechanical properties including tensile and creep behaviour were examined. Based on these results, dependencies between chemical composition and microstructural stability will be elucidated. (orig.)

  6. The influence of tie strength on evolutionary games on networks: An empirical investigation

    Science.gov (United States)

    Buesser, Pierre; Peña, Jorge; Pestelacci, Enea; Tomassini, Marco

    2011-11-01

    Extending previous work on unweighted networks, we present here a systematic numerical investigation of standard evolutionary games on weighted networks. In the absence of any reliable model for generating weighted social networks, we attribute weights to links in a few ways supported by empirical data ranging from totally uncorrelated to weighted bipartite networks. The results of the extensive simulation work on standard complex network models show that, except in a case that does not seem to be common in social networks, taking the tie strength into account does not change in a radical manner the long-run steady-state behavior of the studied games. Besides model networks, we also included a real-life case drawn from a coauthorship network. In this case also, taking the weights into account only changes the results slightly with respect to the raw unweighted graph, although to draw more reliable conclusions on real social networks many more cases should be studied as these weighted networks become available.

  7. Influence of bleaching regimen and time elapsed on microtensile bond strength of resin composite to enamel

    Directory of Open Access Journals (Sweden)

    Fulya Toksoy Topcu

    2017-01-01

    Full Text Available Objectives: The aim of this study was to evaluate the effects of time elapsed since bleaching and different bleaching regimens on the microtensile bond strength of resin composite to enamel. Methodology: Forty flattened buccal enamel surfaces were divided into four groups: An unbleached (control group and three bleaching groups. Control group specimens were not subjected to a bleaching regimen (Group 1, while those in the bleaching groups were bleached as follows: opalescence 10% (Group 2, whiteness perfect 16% (Group 3, and whiteness hydrogen peroxide 35% (Group 4. Thereafter, the bleached specimens were divided into three subgroups (n = 4 teeth each for restoration according to predetermined posttreatment time intervals (immediately, 1 week, and 2 weeks. Bonded specimens were then sectioned and subjected to μTBS testing. The data were analyzed using Kruskal–Wallis and Mann–Whitney U-tests at α = 0.05. Results: There was a significant difference in the μTBS of the resin composite to enamel in groups that were bonded immediately after bleaching and in the control group (P 0.05. Conclusions: Adhesive restorative procedures could not be performed immediately or after 1 week irrespective of the type or concentration of bleaching system used. Composite restorations on bleached enamel surfaces should be performed after an interval of at least 2 weeks.

  8. The influence of ceramic surface treatments on the micro-shear bond strength of composite resin to IPS Empress 2.

    Science.gov (United States)

    Panah, Faride Gerami; Rezai, Sosan Mir Mohammad; Ahmadian, Leila

    2008-07-01

    An increasing demand for esthetic restorations has resulted in the development of new ceramic systems, but fracture of veneering ceramics still remains the primary cause of failure. Porcelain repair frequently involves replacement with composite resin, but the bond strength between composite resin and all-ceramic coping materials has not been studied extensively. The purpose of this study was to evaluate the influence of different ceramic surface treatments on the micro-shear bond strength of composite resin to IPS Empress 2 coping material. Sixteen 7 x 7 x 1 mm(3) lithia disilicate-based core ceramic plates were fabricated using the lost wax technique. The plates were divided into eight groups, and eight different surface treatments were performed: (1) no treatment (NT); (2) airborne-particle abrasion with 50-mum alumina particles (Al); (3) acid etching with 9.6% hydrofluoric acid for 1 min (HF); (4) silane coating (S); (5) AlHF; (6) AlS; (7) HFS; and (8) AlHFS. Then, ten composite resin cylinders (0.8-mm diameter x 0.5-mm height) were light-polymerized onto the ceramic plates in each group. Each specimen was subjected to a shear load at a crosshead speed of 0.5 mm/min until fracture occurred. The fracture sites were examined with scanning electron microscopy (SEM) to determine the location of failure during debonding and to examine the surface treatment effects. One-way analysis of variance (ANOVA) and multiple comparison (Dunnet T3) tests were used for statistical analysis of data. The mean micro-shear bond strength values (SD) in MPa were--NT: 4.10 (3.06), Al: 7.56 (4.11), HF: 14.04 (2.60), S: 14.58 (2.14), AlHF: 15.56 (3.36), AlS: 23.02 (4.17), HFS: 24.7 (4.43), AlHFS: 26.0 (3.71). ANOVA indicated the influence of surface treatment was significant (p Empress 2 was significantly different depending on the surface treatment method. Among the investigated methods, silane coating after airborne-particle abrasion and etching was the most effective surface treatment

  9. Influence of blood contamination during multimode adhesive application on the microtensile bond strength to dentin.

    Science.gov (United States)

    Kucukyilmaz, E; Celik, E U; Akcay, M; Yasa, B

    2017-12-01

    The present study evaluated the effects of blood contamination performed at different steps of bonding on the microtensile bond strength (μTBS) of multimode adhesives to dentin when using the self-etch approach. Seventy-five molars were randomly assigned to three adhesive groups comprising 25 specimens each: two multimode adhesives [Single Bond Universal (SBU) and All-Bond Universal (ABU)] and a conventional one-step self-etch adhesive [Clearfil S3 Bond Plus (CSBP)]. Each group was subdivided as follows: (1) uncontaminated (control): bonding application/light curing as a positive control; (2) contamination-1 (cont-1): bonding application/light curing/blood contamination/dry as a negative control; (3) contamination-2 (cont-2): bonding application/light curing/blood contamination/rinse/dry; (4) contamination-3 (cont-3): bonding application/blood contamination/dry/bonding re-application/light curing; and (5) contamination-4 (cont-4): bonding application/blood contamination/rinse/dry/bonding re-application/light curing. Dentin specimens were prepared for μTBS testing after the composite resin application. Data were analyzed with two-way ANOVA and post-hoc tests (α = 0.05). μTBS values were similar in cont-3 groups, and ABU/cont-4 and corresponding control groups, but were significantly lower in the other groups than in their control groups (P groups showed the lowest μTBS values (P blood contaminants and reapplying the adhesive may regain the dentin adhesion when contamination occurs before light curing. Alternatively, rinsing and drying contaminants followed by adhesive re-application may be effective depending on adhesive type.

  10. How attitude strength and information influence moral decision making: Evidence from event-related potentials.

    Science.gov (United States)

    Hundrieser, Manuela; Stahl, Jutta

    2016-05-01

    Moral judgments are based on complex processing. This study aimed to investigate neural correlates of moral decisions. Participants (N = 32) were asked to express their opinion on various moral issues while ERPs were recorded. After reading texts containing either confirming or contradicting arguments regarding the issues, participants were asked to express their opinion again. A higher N400 amplitude and a higher amplitude of the late positive potential for value-incongruent words compared to value-congruent words could be observed. Furthermore, after participants had read conflicting arguments, slower responses and larger N400 differences (value-incongruent minus value-congruent) were observed. These results showed that language processing for a moral context is influenced by the subjective value system, and it can be assumed that a demanding cognitive elaboration contributed to the observed RT and N400 priming effects. This is the first ERP study comparing moral judgments before and after reading confirming or conflicting information; it revealed that evaluative reasoning can influence neural processing for moral decisions. © 2016 Society for Psychophysiological Research.

  11. Influence of Using Clinical Microscope as Auxiliary to Perform Mechanical Cleaning of Post Space: A Bond Strength Analysis.

    Science.gov (United States)

    Ferreira, Ricardo; Prado, Maíra; de Jesus Soares, Adriana; Zaia, Alexandre Augusto; de Souza-Filho, Francisco José

    2015-08-01

    The aim of the present study was to evaluate the influence of using a clinical microscope while performing mechanical cleaning of post space walls on the bond strength of a fiberglass post to dentin. Forty-five bovine roots were used. After preparation, roots were filled using gutta-percha and Pulp Canal Sealer (SybronEndo, Orange, CA). Subsequently, for post space preparation, the roots were divided into 3 groups: control (only heat condenser + specific bur of the post system); cleaning without a microscope, mechanical cleaning (after the procedure described in the control group, round burs were used to improve cleaning); and cleaning with a microscope, mechanical cleaning performed with round burs visualized under a clinical microscope. Then, fiberglass posts were cemented. The roots were prepared and evaluated by the push-out test. Data were analyzed using Kruskal-Wallis and Student-Newman-Keuls tests (P microscope (cervical 1.66 ± 2.3, middle 0.65 ± 1.1, apical 0.79 ± 1.2, and total1.04 ± 1.7), and cleaning with a microscope (cervical 3.26 ± 2.8, middle 1.97 ± 3.5, apical 1.85 ± 4.1, and total 2.37 ± 3.5). In the cleaning with a microscope group, the bond strength values were significantly higher than those in the other groups. In all groups, the main failure pattern was adhesive between cement and dentin. The use of a clinical microscope while performing mechanical cleaning during post space preparation improved the bond strength of a fiberglass post to dentin. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  12. Fire performance, mechanical strength and dimensional stability of wood flour–polyethylene composites under the influence of different fire retardants

    Directory of Open Access Journals (Sweden)

    Mehdi Roohani

    2017-05-01

    Full Text Available Flammability is one of the most important parameters that often limit the application range of wood plastic composites. Therefore, the improvements of retardancy performance of these products have a considerable impact. The aim of this work was to evaluate the influence of expandable graphite (EG and its combination with aluminum tirhydroxide (ATH, inorganic phosphate (IP and melamine borate (MB on the flammability of wood flour–polyethylene composites. Composites were prepared by the melt compounding method and cone calorimetry as well as limited oxygen index (LOI tests was employed to study their flammability properties. Also, the effect of different fire retardants on the mechanical strength and water uptake of samples were investigated. Cone calorimetry characterization indicated that with incorporation of fire retardans heat release rate and burning rate decrease and char residual as well as the time to ignition increase. These findings ascribed to formation of char layer by fire retardants. The combination of EG and other fire retardants yielded better improvements in flame retardancy in comparison to the sample that has just EG as flame retardant. The LOI test was used to determine the lowest concentration of oxygen at which a material will maintain combustion in a flowing mixture of oxygen and nitrogen. The results showed that inclusion of fire retardants improve the LOI of sample. Furthermore, the presence of fire retardants decreased the tensile and flexural resistance (strength and modules and impact strength of samples, and increased the water absorption as well as thickness swelling. Generally, among the different treatments examined, the EG–ATH retardancy system showed highest potential in flame retardancy of composites.

  13. [Influence of retainer design on fixation strength of resin-bonded glass fiber reinforced composite fixed cantilever dentures].

    Science.gov (United States)

    Petrikas, O A; Voroshilin, Iu G; Petrikas, I V

    2013-01-01

    Fiber-reinforced composite (FRC) fixed partial dentures (FPD) have become an accepted part of the restorative dentist's armamentarium. The aim of this study was to evaluate in vitro the influence of retainer design on the strength of two-unit cantilever resin-bonded glass FRC-FPDs. Four retainer designs were tested: a dual wing, a dual wing + horizontal groove, a dual wing + occlusal rest and a step-box. Of each design on 7 human mandibular molars, FRC-FPDs of a premolar size were produced. The FRC framework was made of resin Revolution (Kerr) impregnated glass fibers (GlasSpan, GlasSpan) and veneered with hybrid resin composite (Charisma, Kulzer). Revolution (Kerr) was used as resin luting cement. FRC-FPDs were loaded to failure in a universal testing machine. T (Student's)-test was used to evaluate the data. The four designs were analyzed with finite element analysis (FEA) to reveal the stress distribution within the tooth/restoration complex. Significantly lower fracture strengths were observed with inlay-retained FPDs (step-box: 172±11 N) compared to wing-retained FPDs (poptimal design for replacement of a single premolar by means of a two-unit cantilever FRC-FPDs.

  14. Influence of application method on surface free-energy and bond strength of universal adhesive systems to enamel.

    Science.gov (United States)

    Imai, Arisa; Takamizawa, Toshiki; Sai, Keiichi; Tsujimoto, Akimasa; Nojiri, Kie; Endo, Hajime; Barkmeier, Wayne W; Latta, Mark A; Miyazaki, Masashi

    2017-10-01

    The aim of the present study was to determine the influence of different adhesive application methods and etching modes on enamel bond effectiveness of universal adhesives using shear bond strength (SBS) testing and surface free-energy (SFE) measurements. The adhesives Scotchbond Universal, All-Bond Universal, Adhese Universal, and G-Premio Bond were used. Prepared bovine enamel specimens were divided into four groups, based on type of adhesive, and subjected to the following surface treatments: (i) total-etch mode with active application; (ii) total-etch mode with inactive application; (iii) self-etch mode with active application; and (iv) self-etch mode with inactive application. Bonded specimens were subjected to SBS testing. The SFE of the enamel surfaces with adhesive was measured after rinsing with acetone and water. The SBS values in total-etch mode were significantly higher than those in self-etch mode. In total-etch mode, significantly lower SBS values were observed with active application compared with inactive application; in contrast, in self-etch mode there were no significant differences in SBS between active and inactive applications. A reduction in total SFE was observed for active application compared with inactive application. The interaction between etching mode and application method was statistically significant, and the application method significantly affected enamel bond strength in total-etch mode. © 2017 Eur J Oral Sci.

  15. Influence of different pre-etching times on fatigue strength of self-etch adhesives to dentin.

    Science.gov (United States)

    Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Suzuki, Takayuki; Scheidel, Donal D; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

    2016-04-01

    The purpose of this study was to use shear bond strength (SBS) and shear fatigue strength (SFS) testing to determine the influence on dentin bonding of phosphoric acid pre-etching times before the application of self-etch adhesives. Two single-step self-etch universal adhesives [Prime & Bond Elect (EL) and Scotchbond Universal (SU)], a conventional single-step self-etch adhesive [G-aenial Bond (GB)], and a two-step self-etch adhesive [OptiBond XTR (OX)] were used. The SBS and SFS values were obtained with phosphoric acid pre-etching times of 3, 10, or 15 s before application of the adhesives, and for a control without pre-etching. For groups with 3 s of pre-etching, SU and EL showed higher SBS values than control groups. No significant difference was observed for GB among the 3 s, 10 s, and control groups, but the 15 s pre-etching group showed significantly lower SBS and SFS values than the control group. No significant difference was found for OX among the pre-etching groups. Reducing phosphoric acid pre-etching time can minimize the adverse effect on dentin bonding durability for the conventional self-etch adhesives. Furthermore, a short phosphoric acid pre-etching time enhances the dentin bonding performance of universal adhesives. © 2016 Eur J Oral Sci.

  16. Waiting Time for Coronal Preparation and the Influence of Different Cements on Tensile Strength of Metal Posts

    Directory of Open Access Journals (Sweden)

    Ilione Kruschewsky Costa Sousa Oliveira

    2012-01-01

    Full Text Available This study aimed to assess the effect of post-cementation waiting time for core preparation of cemented cast posts and cores had on retention in the root canal, using two different luting materials. Sixty extracted human canines were sectioned 16 mm from the root apex. After cast nickel-chromium metal posts and cores were fabricated and luted with zinc phosphate (ZP cement or resin cement (RC, the specimens were divided into 3 groups (n = 10 according to the waiting time for core preparation: no preparation (control, 15 minutes, or 1 week after the core cementation. At the appropriate time, the specimens were subjected to a tensile load test (0.5 mm/min until failure. Two-way ANOVA (time versus cement and the Tukey tests (P < 0.05 showed significantly higher (P < 0.05 tensile strength values for the ZP cement groups than for the RC groups. Core preparation and post-cementation waiting time for core recontouring did not influence the retention strength. ZP was the best material for intraradicular metal post cementation.

  17. Influence of Sulfate-Reducing Bacteria on the Corrosion Residual Strength of an AZ91D Magnesium Alloy

    Science.gov (United States)

    Zhu, Xianyong; Liu, Yaohui; Wang, Qiang; Liu, Jiaan

    2014-01-01

    In this paper, the corrosion residual strength of the AZ91D magnesium alloy in the presence of sulfate-reducing bacteria is studied. In the experiments, the chemical composition of corrosion film was analyzed by a scanning electron microscope with energy dispersive X-ray spectroscopy. In addition, a series of instruments, such as scanning electronic microscope, pH-meter and an AG-10TA materials test machine, were applied to test and record the morphology of the corrosion product, fracture texture and mechanical properties of the AZ91D magnesium alloy. The experiments show that the sulfate-reducing bacteria (SRB) play an important role in the corrosion process of the AZ91D magnesium alloy. Pitting corrosion was enhanced by sulfate-reducing bacteria. Corrosion pits are important defects that could lead to a significant stress concentration in the tensile process. As a result, sulfate-reducing bacteria influence the corrosion residual strength of the AZ91D magnesium alloy by accelerating pitting corrosion. PMID:28788236

  18. The influence of the scale effect and high temperatures on the strength and strains of high performance concrete

    Directory of Open Access Journals (Sweden)

    Korsun Vladimyr Ivanovych

    2014-03-01

    Full Text Available The most effective way to reduce the structure mass, labor input and expenses for its construction is to use modern high-performance concrete of the classes С50/60… С90/105, which possess high physical and mathematic characteristics. One of the constraints for their implementation in mass construction in Ukraine is that in design standards there are no experimental data on the physical and mathematic properties of concrete of the classes more than С50/60. Also there are no exact statements on calculating reinforced concrete structures made of high-performance concretes.The authors present the results of experimental research of the scale effect and short-term and long-term heating up to +200 ° C influence on temperature and shrinkage strain, on strength and strain characteristics under compression and tensioning of high-strength modified concrete of class C70/85. The application of high performance concretes is challenging in the process of constructing buildings aimed at operating in high technological temperatures: smoke pipes, coolers, basins, nuclear power plants' protective shells, etc. Reducing cross-sections can lead to reducing temperature drops and thermal stresses in the structures.

  19. Mind-muscle connection training principle: influence of muscle strength and training experience during a pushing movement.

    Science.gov (United States)

    Calatayud, Joaquin; Vinstrup, Jonas; Jakobsen, Markus D; Sundstrup, Emil; Colado, Juan Carlos; Andersen, Lars L

    2017-07-01

    To investigate the effect of different attentional focus conditions on muscle activity during the push-up exercise and to assess the possible influence of muscle strength and training experience. Eighteen resistance-trained men performed 1RM bench press testing and were familiarized with the procedure during the first session. In the second session, three different conditions were randomly performed: regular push-up and push-up focusing on using the pectoralis major and triceps brachii muscles, respectively. Surface electromyography (EMG) was recorded and analyzed (EMG normalized to max; nEMG) for the triceps brachii and pectoralis major muscles. Participants had on average 8 (SD 6) years of training experience and 1RM of 1.25 (SD 0.28) kg per kg bodyweight. Focusing on using pectoralis major increased activity in this muscle by 9% nEMG (95% CI 5-13; Cohen's d 0.60) compared with the regular condition. Triceps activity was not significantly influenced by triceps focus although borderline significant, with a mean difference of 5% nEMG (95% CI 0-10; Cohen's d 0.30). However, years of training experience was positively associated with the ability to selectively activate the triceps (β = 0.41, P = 0.04), but not the pectoralis. Bench press 1RM was not significantly associated with the ability to selectively activate the muscles. Pectoralis activity can be increased when focusing on using this muscle during push-ups, whereas the ability to do this for the triceps is dependent on years of training experience. Maximal muscle strength does not appear to be a decisive factor for the ability to selectively activate these muscles.

  20. Does Histologic Subtype Influence the Post-Operative Outcome in Spinal Meningioma?

    Science.gov (United States)

    Zham, Hanieh; Moradi, Afshin; Rakhshan, Azadeh; Zali, Alireza; Rahbari, Ali; Raee, Mohammadreza; Ashrafi, Farzad; Ahadi, Mahsa; Larijani, Leila; Baikpour, Masoud; Khayamzadeh, Maryam

    2016-04-01

    Postoperative outcome of spinal meningiomas is an important issue in surgery decision-making. There are limited and conflicting data in the literature about the prognostic factors influencing recovery, especially about the histopathologic subtypes. This study was carried out to evaluate the effect of some of these factors on postoperative outcome. This study was performed on 39 patients operated for spinal meningioma between October 1998 and January 2012; their histopathologic subtype was determined according to WHO criteria. The follow up period ranged between 8 - 120 months. The influence of histopathologic subtype, grade, age, sex, surgical approach, local adhesion and anatomical location was assessed according to Frankel classification of neurologic deficit. From a total number of 39 spinal meningiomas, 34 cases were WHO grade I, from which 15 cases were psammomatous, 7 cases were meningothelial, 9 cases were transitional and 3 cases were fibroblastic. Five cases were grade II, 3 of which had clear cell appearance and the remaining 2 had chordoid appearance. The mean age was 51.6 (22 to 76) years; 25 cases were female and 14 cases were male. This study revealed that grade II meningioma cases had poor prognosis in all 5 cases and psammomatous subtype had poor postoperative outcome in 40% of cases while the other subtypes had good outcome in all cases (P = 0.026). Cervical location of the tumor was also related with poor outcome in 37.5% of the cases, while 22.5% had poor outcome in other locations (P = 0.029). Age below and above 45 years and sex had no significant influence on the outcome. Spinal meningiomas of psammomatous type and grade II spinal meningiomas are associated with less favorable postoperative neurologic outcome. Cervical location has also a negative correlation with a good outcome.

  1. Influence of Cutting Temperature on the Tensile Strength of a Carbon Fiber-Reinforced Polymer

    Directory of Open Access Journals (Sweden)

    Jérémy Delahaigue

    2017-12-01

    Full Text Available Carbon fiber-reinforced plastics (CFRP have seen a significant increase in use over the years thanks to their specific properties. Despite continuous improvements in the production methods of laminated parts, a trimming operation is still necessary to achieve the functional dimensions required by engineering specifications. Laminates made of carbon fibers are very abrasive and cause rapid tool wear, and require high cutting temperatures. This creates damage to the epoxy matrix, whose glass-transition temperature is often recognized to be about 180 °C. This study aims to highlight the influence of the cutting temperature generated by tool wear on the surface finish and mechanical properties obtained from tensile tests. Trimming operations were performed on a quasi-isotropic 24-ply carbon/epoxy laminate, of 3.6 mm thickness, with a 6 flutes diamond-coated (CVD cutter. The test specimens of 6 mm and 12 mm wide were obtained by trimming. The reduced width of the coupons allowed amplification of the effect of defects on the measured properties by increasing the proportion of coupon cross-section occupied by the defects. A new tool and a tool in an advanced state of wear were used to generate different cutting temperatures. Results showed a cutting temperature of 300 °C for the new tool and 475 °C for the worn tool. The analysis revealed that the specimens machined with the new tool have no thermal damage and the cut is clean. The plies oriented at −45° presented the worst surface finish according to the failure mode of the fiber. For the worn tool, the surface was degraded and the matrix was carbonized. After cutting, observations showed a degraded resin spread on the machined surface, which reduced the surface roughness and hid the cutting defects. In support of these observations, the tensile tests showed no variation of the mechanical properties for the 12 mm-wide specimens, but did show a 10% loss in mechanical properties for the 6 mm

  2. Can Quantitative Muscle Strength and Functional Motor Ability Differentiate the Influence of Age and Corticosteroids in Ambulatory Boys with Duchenne Muscular Dystrophy?

    Science.gov (United States)

    Buckon, Cathleen; Sienko, Susan; Bagley, Anita; Sison-Williamson, Mitell; Fowler, Eileen; Staudt, Loretta; Heberer, Kent; McDonald, Craig M; Sussman, Michael

    2016-07-08

    In the absence of a curative treatment for Duchenne Muscular Dystrophy (DMD), corticosteroid therapy (prednisone, deflazacort) has been adopted as the standard of care, as it slows the progression of muscle weakness and enables longer retention of functional mobility. The ongoing development of novel pharmacological agents that target the genetic defect underlying DMD offer hope for a significant alteration in disease progression; however, substantiation of therapeutic efficacy has proved challenging. Identifying functional outcomes sensitive to the early, subtle changes in muscle function has confounded clinical trials. Additionally, the alterations in disease progression secondary to corticosteroid therapy are not well described making it difficult to ascertain the benefits of novel agents, often taken concurrently with corticosteroids. The purpose of this study was to examine outcome responsiveness to corticosteroid therapy and age at the onset of a natural history study of ambulatory boys with DMD. Eighty-five ambulatory boys with DMD (mean age 93 mo, range 49 to 180 mo) were recruited into this study. Fifty participants were on corticosteroid therapy, while 33 were corticosteroid naïve at the baseline assessment. Within each treatment group boys were divided in two age groups, 4 to 7 years and 8 and greater years of age. The Biodex System 3 Pro isokinetic dynamometer was used to assess muscle strength. Motor skills were assessed using the upper two dimensions (standing/walking, running & jumping) of the Gross Motor Function Measure (GMFM 88) and Timed Motor Tests (TMTs) (10-meter run, sit to stand, supine to stand, climb 4-stairs). Two way analysis of variance and Pearson correlations were used for analysis. A main effect for age was seen in select lower extremity muscle groups (hip flexors, knee extensors and ankle dorsiflexors), standing dimension skills, and all TMTs with significantly greater weakness and loss of motor skill ability seen in the older age

  3. The Stereotype-Matching Effect: Greater Influence on Functioning When Age Stereotypes Correspond to Outcomes

    Science.gov (United States)

    Levy, Becca R.; Leifheit-Limson, Erica

    2009-01-01

    Older individuals assimilate, and are targeted by, contradictory positive and negative age stereotypes. It was unknown whether the influence of stereotype valence is stronger when the stereotype content corresponds to the outcome domain. We randomly assigned older individuals to either positive-cognitive, negative-cognitive, positive-physical, or negative-physical subliminal-age-stereotype groups and assessed cognitive and physical outcomes. As predicted, when the age stereotypes corresponded to the outcome domains, their valence had a significantly greater impact on cognitive and physical performance. This suggests that if a match occurs, it is more likely to generate expectations that become self-fulfilling prophecies. PMID:19290757

  4. Feasibility of resistance training in adult McArdle patients: clinical outcomes and muscle strength and mass benefits.

    Science.gov (United States)

    Santalla, Alfredo; Munguía-Izquierdo, Diego; Brea-Alejo, Lidia; Pagola-Aldazábal, Itziar; Díez-Bermejo, Jorge; Fleck, Steven J; Ara, Ignacio; Lucia, Alejandro

    2014-01-01

    We analyzed the effects of a 4-month resistance (weight lifting) training program followed by a 2-month detraining period in 7 adult McArdle patients (5 female) on: muscle mass (assessed by DXA), strength, serum creatine kinase (CK) activity and clinical severity. Adherence to training was ≥84% in all patients and no major contraindication or side effect was noted during the training or strength assessment sessions. The training program had a significant impact on total and lower extremities' lean mass (P training by +855 g (95% confidence interval (CI): 30, 1679) and +547 g (95%CI: 116, 978), respectively, and significantly decreasing with detraining. Body fat showed no significant changes over the study period. Bench press and half-squat performance, expressed as the highest value of average muscle power (W) or force (N) in the concentric-repetition phase of both tests showed a consistent increase over the 4-month training period, and decreased with detraining. Yet muscle strength and power detraining values were significantly higher than pre-training values, indicating that a training effect was still present after detraining. Importantly, all the participants, with no exception, showed a clear gain in muscle strength after the 4-month training period, e.g., bench press: +52 W (95% CI: 13, 91); half-squat: +173 W (95% CI: 96, 251). No significant time effect (P > 0.05) was noted for baseline or post strength assessment values of serum CK activity, which remained essentially within the range reported in our laboratory for McArdle patients. All the patients changed to a lower severity class with training, such that none of them were in the highest disease severity class (3) after the intervention and, as such, they did not have fixed muscle weakness after training. Clinical improvements were retained, in all but one patient, after detraining, such that after detraining all patients were classed as class 1 for disease severity.

  5. Influence of the number of cycles on shear fatigue strength of resin composite bonded to enamel and dentin using dental adhesives in self-etching mode.

    Science.gov (United States)

    Tsujimoto, Akimasa; Barkmeier, Wayne W; Erickson, Robert L; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

    2018-01-30

    The influence of the number of cycles on shear fatigue strength to enamel and dentin using dental adhesives in self-etch mode was investigated. A two-step self-etch adhesive and two universal adhesives were used to bond to enamel and dentin in self-etch mode. Initial shear bond strength and shear fatigue strength to enamel and dentin using the adhesive in self-etch mode were determined. Fatigue testing was used with 20 Hz frequency and cycling periods of 50,000, 100,000 and 1,000,000 cycles, or until failure occurred. For each of the cycling periods, there was no significant difference in shear fatigue strength across the cycling periods for the individual adhesives. Differences in shear fatigue strength were found between the adhesives within the cycling periods. Regardless of the adhesive used in self-etch mode for bonding to enamel or dentin, shear fatigue strength was not influenced by the number of cycles used for shear fatigue strength testing.

  6. Feasibility and outcomes of a classical Pilates program on lower extremity strength, posture, balance, gait, and quality of life in someone with impairments due to a stroke.

    Science.gov (United States)

    Shea, Sarah; Moriello, Gabriele

    2014-07-01

    Pilates is a method that can potentially be used for stroke rehabilitation to address impairments in gait, balance, strength, and posture. The purpose of this case report was to document the feasibility of using Pilates and to describe outcomes of a 9-month program on lower extremity strength, balance, posture, gait, and quality of life in an individual with stroke. The participant was taught Pilates exercises up to two times per week for nine months in addition to traditional rehabilitation in the United States. Outcomes were assessed using the Berg Balance Scale (BBS), Stroke Impact Scale (SIS), GAITRite System(®), 5 repetition sit-to-stand test (STST), and flexicurve. Improvements were found in balance, lower extremity strength, and quality of life. Posture and gait speed remained the same. While these changes cannot be specifically attributed to the intervention, Pilates may have added to his overall rehabilitation program and with some modifications was feasible to use in someone with a stroke. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Influence of air-powder polishing on bond strength and surface-free energy of universal adhesive systems.

    Science.gov (United States)

    Tamura, Yukie; Takamizawa, Toshiki; Shimamura, Yutaka; Akiba, Shunsuke; Yabuki, Chiaki; Imai, Arisa; Tsujimoto, Akimasa; Kurokawa, Hiroyasu; Miyazaki, Masashi

    2017-11-29

    The influences of air-powder polishing with glycine or sodium bicarbonate powders on shear bond strengths (SBS) and surface-free energies of universal adhesives were examined. Scotchbond Universal Adhesive (SU, 3M ESPE), G-Premio Bond (GP, GC), Adhese Universal (AU, Ivoclar Vivadent), and All-Bond Universal (AB, Bisco) were used in this study. Bovine dentin surfaces were air polished with glycine or sodium bicarbonate powders prior to the bonding procedure, and resin pastes were bonded to the dentin surface using universal adhesives. SBSs were determined after 24-h storage in distilled water at 37°C. Surface-free energy was then determined by measuring contact angles using three test liquids on dentin surfaces. Significantly lower SBSs were observed for dentin that was air-powder polished and surface-free energies were concomitantly lowered. This study indicated that air-powder polishing influences SBSs and surface-free energies. However, glycine powder produced smaller changes in these surface parameters than sodium bicarbonate.

  8. Influence of peer review on the reporting of primary outcome(s) and statistical analyses of randomised trials.

    Science.gov (United States)

    Hopewell, Sally; Witt, Claudia M; Linde, Klaus; Icke, Katja; Adedire, Olubusola; Kirtley, Shona; Altman, Douglas G

    2018-01-11

    Selective reporting of outcomes in clinical trials is a serious problem. We aimed to investigate the influence of the peer review process within biomedical journals on reporting of primary outcome(s) and statistical analyses within reports of randomised trials. Each month, PubMed (May 2014 to April 2015) was searched to identify primary reports of randomised trials published in six high-impact general and 12 high-impact specialty journals. The corresponding author of each trial was invited to complete an online survey asking authors about changes made to their manuscript as part of the peer review process. Our main outcomes were to assess: (1) the nature and extent of changes as part of the peer review process, in relation to reporting of the primary outcome(s) and/or primary statistical analysis; (2) how often authors followed these requests; and (3) whether this was related to specific journal or trial characteristics. Of 893 corresponding authors who were invited to take part in the online survey 258 (29%) responded. The majority of trials were multicentre (n = 191; 74%); median sample size 325 (IQR 138 to 1010). The primary outcome was clearly defined in 92% (n = 238), of which the direction of treatment effect was statistically significant in 49%. The majority responded (1-10 Likert scale) they were satisfied with the overall handling (mean 8.6, SD 1.5) and quality of peer review (mean 8.5, SD 1.5) of their manuscript. Only 3% (n = 8) said that the editor or peer reviewers had asked them to change or clarify the trial's primary outcome. However, 27% (n = 69) reported they were asked to change or clarify the statistical analysis of the primary outcome; most had fulfilled the request, the main motivation being to improve the statistical methods (n = 38; 55%) or avoid rejection (n = 30; 44%). Overall, there was little association between authors being asked to make this change and the type of journal, intervention, significance of the

  9. Influence of pre-existing inflammation on the outcome of acute coronary syndrome

    DEFF Research Database (Denmark)

    Odeberg, J.; Freitag, M.; Forssell, Henrik

    2016-01-01

    Objectives: Inflammation is a well-established risk factor for the development of coronary artery disease (CAD) and acute coronary syndrome (ACS). However, less is known about its influence on the outcome of ACS. The aim of this study was to determine if blood biomarkers of inflammation were...... that a pre-existing low-grade inflammation may dispose towards MI over UA....

  10. The influence of perceived characteristics of management development programs on employee outcomes.

    NARCIS (Netherlands)

    Ardts, J.C.A.; van der Velde, M.E.G.; Maurer, T.

    2010-01-01

    Employees’ perceptions of Management Development (MD) programs is the topic of this study. The purpose is to examine the influence of three important perceived characteristics of MD programs on relevant MD outcomes. The MD characteristics are: availability of role models, perceived control, and

  11. The Influence of Investment in Workplace Learning on Learning Outcomes and Organizational Performance

    Science.gov (United States)

    Park, Yoonhee; Jacobs, Ronald L.

    2011-01-01

    Although the importance of workplace learning has been recognized in research and practice, there is little empirical support that describes how workplace learning, including both formal and informal learning, is linked to organizational performance. This study investigated the influence of investment in workplace learning on learning outcomes and…

  12. The Level of Alexithymia in Alcohol-Dependent Patients Does Not Influence Outcomes after Inpatient Treatment

    NARCIS (Netherlands)

    Haan, H.A. de; Schellekens, A.F.A.; Palen, J.A.M. van der; Verkes, R.J.; Buitelaar, J.K.; Jong, C.A.J. de

    2012-01-01

    Background: The inability of individuals with Alcohol Use Disorders (AUD) to recognize and describe their feelings and cravings may be due to alexithymia. Previous researches have shown evidence for a negative influence of alexithymia on treatment outcomes in patients with AUD. Therefore, it was

  13. The level of alexithymia in alcohol-dependent patients does not influence outcomes after inpatient treatment.

    NARCIS (Netherlands)

    Haan, H.A. de; Schellekens, A.F.A.; Palen, J.A.M. van der; Verkes, R.J.; Buitelaar, J.K.; Jong, C.A.J. de

    2012-01-01

    BACKGROUND: The inability of individuals with Alcohol Use Disorders (AUD) to recognize and describe their feelings and cravings may be due to alexithymia. Previous researches have shown evidence for a negative influence of alexithymia on treatment outcomes in patients with AUD. Therefore, it was

  14. The level of Alexithymia in alcohol-dependent patients does not influence outcomes after inpatient treatment

    NARCIS (Netherlands)

    de Haan, Hein A.; Schellekens, Arnt F.A.; van der Palen, Jacobus Adrianus Maria; Verkes, Robbert-Jan; Buitelaar, Jan K.; de Jong, Cor A.J.

    2012-01-01

    Background: The inability of individuals with Alcohol Use Disorders (AUD) to recognize and describe their feelings and cravings may be due to alexithymia. Previous researches have shown evidence for a negative influence of alexithymia on treatment outcomes in patients with AUD. Therefore, it was

  15. Influence of gender on EVAR outcomes with new low-profile devices

    DEFF Research Database (Denmark)

    Bendermacher, B L W; Grootenboer, Nathalie; Cuypers, Ph W

    2013-01-01

    Women have not benefitted to the same extent as men of endovascular abdominal aortic repair (EVAR). Besides differences in hormones and the higher rate of undiagnosed cardiovascular disease, there are anatomical differences between men and women influencing the outcome of endovascular treatment o...

  16. The Influence of Contextual Factors on the Sustainability of Professional Development Outcomes

    Science.gov (United States)

    Sandholtz, Judith Haymore; Ringstaff, Cathy

    2016-01-01

    This study investigated how contextual factors influenced the sustainability of outcomes from a 3-year, state-funded professional development program that provided science assistance for K-2 teachers in small, rural school districts. The research used a case-study approach with a purposive sample of five elementary schools that varied in…

  17. Social distance influences the outcome evaluation of cooperation and conflict: Evidence from event-related potentials.

    Science.gov (United States)

    Chen, Yezi; Lu, Jiamei; Wang, Yiwen; Feng, Zhouqi; Yuan, Bo

    2017-04-24

    Previous research shows that social distance plays an important role in promoting cooperation and that subtle cues that reduce social distance increase the tendency to cooperate. However, it is unclear how social distance influences our outcome evaluation of cooperative and conflict feedback. The present study investigated the influence of social distance on cooperative and conflict behavior and the evaluation process of the cooperative and conflict outcomes, using the event-related potentials (ERPs) technique. We recorded ERPs from 14 normal adults playing a social game task against a friend and a stranger. The results showed that the FRN (Feedback Related Negativity) and P300 were affected by the opponent's choice to cooperate or aggress; however, only the P300 was affected by social distance. Specifically, when the opponent chose to cooperate, the feedback elicited a smaller FRN and a larger P300 amplitude; and compared with playing against friends, the P300 had a larger amplitude when participants gaming with strangers. Our results indicate that at the early stage of the evaluation of cooperation and conflict outcomes, individuals may initially and quickly encode the valence of outcomes, judging whether an outcome is consistent with their expectations. However, at the late stage, which involves a top-down cognitive appraisal process, some social factors, such as social distance, may moderate processing of attention resource allocation of feedback about outcomes, and of higher-level motivation/affective appraisal. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Influence of Heat-Treatment on the Adhesive Strength between a Micro-Sized Bonded Component and a Silicon Substrate under Bend and Shear Loading Conditions

    International Nuclear Information System (INIS)

    Ishiyama, Chiemi

    2012-01-01

    Adhesive bend and shear tests of micro-sized bonded component have been performed to clarify the relationship between effects of heat-treatment on the adhesive strength and the bonded specimen shape using Weibull analysis. Multiple micro-sized SU-8 columns with four different diameters were fabricated on a Si substrate under the same fabrication condition. Heat-treatment can improve both of the adhesive bend and shear strength. The improvement rate of the adhesive shear strength is much larger than that of the adhesive bend strength, because the residual stress, which must change by heat-treatment, should effect more strongly on the shear loading. In case of bend type test, the adhesive bend strength in the smaller diameters (50 and 75 μm) widely vary, because the critical size of the natural defect (micro-crack) should vary more widely in the smaller diameters. In contrast, in case of shear type test, the adhesive shear strengths in each diameter of the columns little vary. This suggests that the size of the natural defects may not strongly influence on the adhesive shear strength. All the result suggests that both of the adhesive bend and shear strengths should be complicatedly affected by heat-treatment and the bonded columnar diameter

  19. Influence of core-finishing intervals on tensile strength of cast posts-and-cores luted with zinc phosphate cement

    Directory of Open Access Journals (Sweden)

    Michele Andrea Lopes Iglesias

    2012-08-01

    Full Text Available The core finishing of cast posts-and-cores after luting is routine in dental practice. However, the effects of the vibrations produced by the rotary cutting instruments over the luting cements are not well-documented. This study evaluated the influence of the time intervals that elapsed between the cementation and the core-finishing procedures on the tensile strength of cast posts-and-cores luted with zinc phosphate cement. Forty-eight bovine incisor roots were selected, endodontically treated, and divided into four groups (n = 12: GA, control (without finishing; GB, GC, and GD, subjected to finishing at 20 minutes, 60 minutes, and 24 hours after cementation, respectively. Root canals were molded, and the resin patterns were cast in copper-aluminum alloy. Cast posts-and-cores were luted with zinc phosphate cement, and the core-finishing procedures were applied according to the groups. The tensile tests were performed at a crosshead speed of 0.5 mm/min for all groups, 24 hours after the core-finishing procedures. The data were subjected to one-way analysis of variance (ANOVA and Tukey's test (α = 0.05. No significant differences were observed in the tensile strengths between the control and experimental groups, regardless of the time interval that elapsed between the luting and finishing steps. Within the limitations of the present study, it was demonstrated that the core-finishing procedures and time intervals that elapsed after luting did not appear to affect the retention of cast posts-and-cores when zinc phosphate cement was used.

  20. Bond Strength of Resin Composite to Dentin with Different Adhesive Systems: Influence of Relative Humidity and Application Time.

    Science.gov (United States)

    Amsler, Fabienne; Peutzfeldt, Anne; Lussi, Adrian; Flury, Simon

    2015-06-01

    To investigate the influence of relative humidity and application time on bond strength to dentin of different classes of adhesive systems. A total of 360 extracted human molars were ground to mid-coronal dentin. The dentin specimens were treated with one of six adhesive systems (Syntac Classic, OptiBond FL, Clearfil SE Bond, AdheSE, Xeno Select, or Scotchbond Universal), and resin composite (Filtek Z250) was applied to the treated dentin surface under four experimental conditions (45% relative humidity/application time according to manufacturers' instructions; 45% relative humidity/reduced application time; 85% relative humidity/application time according to manufacturers' instructions; 85% relative humidity/reduced application time). After storage (37°C, 100% humidity, 24 h), shear bond strength (SBS) was measured and data analyzed with nonparametric ANOVA followed by Kruskal-Wallis tests and Mann-Whitney U-tests with Bonferroni-Holm correction for multiple testing (level of significance: α = 0.05). Increased relative humidity and reduced application time had no effect on SBS for Clearfil SE Bond and Scotchbond Universal (p = 1.00). For Syntac Classic, OptiBond FL, AdheSE, and Xeno Select there was no effect on SBS of reduced application time of the adhesive system (p ≥ 0.403). However, increased relative humidity significantly reduced SBS for Syntac Classic, OptiBond FL, and Xeno Select irrespective of application time (p ≤ 0.003), whereas for AdheSE, increased relative humidity significantly reduced SBS at recommended application time only (p = 0.002). Generally, increased relative humidity had a detrimental effect on SBS to dentin, but reduced application time had no effect.

  1. INFLUENCE OF QUARTZ CERAMICS SINGLE-STAGE PROCESSING BY GEL-FORMING WATER SOLUTIONS ON ITS STRENGTH

    Directory of Open Access Journals (Sweden)

    S. K. Evstropiev

    2014-09-01

    Full Text Available The main research results of the influence of quartz ceramics processing by silicon- and aluminum-containing gel- forming water solutions on its durability and porosity are given. Aqueous-alcoholic solutions based on tetraethoxysilane (TEOS, Si(C2H5O4 with additives of aluminum nitrate are proposed for impregnation of porous quartz ceramics samples. Ceramic samples are being impregnated with solutions at the room temperature for 12 minutes. After impregnation they are being exposed to drying at the room temperature for 24 hours and heat treatment in the electric muffle furnace. The made experiments show that impregnation of quartz ceramics porous samples by gel-forming solutions leads to durability growth of not burned samples by 6-7 times even without additional heat treatment. High-temperature heat treatment of previously impregnated ceramic samples leads to decomposition of aluminum nitrate and removal of fossils, and also to hardening of the formed additional bonds between material particles. It considerably improves strength characteristics of quartz ceramics as well. Thus, the possibility of considerable hardening of porous quartz ceramics and stability growth of its strength properties by preliminary impregnation of silicon- and aluminum-bearing gel-forming solutions even without additional heat treatment is experimentally shown. It is revealed that impregnation of porous quartz ceramic samples by these solutions leads only to insignificant reduction of porosity of samples. Subsequent heat treatment of the impregnated porous ceramic samples at the temperatures, equal to 900-1200oC, results in additional significant increase in their mechanical durability.

  2. Investigating the Influence of Micro-Arc Oxide Coating on Rigidity and Strength of Long Force Elements of Spacecraft

    Directory of Open Access Journals (Sweden)

    V. K. Shatalov

    2014-01-01

    Full Text Available Outboard elements (arms, towers are widely used in spacecraft structure for setting-out of a payload; their high stiffness-weight ratio provides an opportunity to decrease the mass. The deployment unit is considered as an example of outboard structure. Its strength beams work under special conditions in operation. At the transportation stage beams are under considerable vibration loads. Therefore for increasing the natural resonance frequency it is rational to increase their rigidity. Using the micro-arc oxide coating suggests itself because the modulus of elasticity of the micro-arc oxide coating is more than that of the aluminium alloy. The beams suffer considerable bending load at the step of deploying; therefore the aluminium alloy with the micro-arc oxide coating must have suitable loading capacity, in addition to increased rigidity.Influence of micro-arc oxide coating on the rigidity and strength of tubes f rom aluminium alloy is investigated. It is determined that forming the micro-arc oxide coating on thin-walled tubes with a ratio of the coating area to the cross-section area of more than 25% is the most rational. In this case the rigidity of composite material considerably exceeds the rigidity of the aluminium alloy of the same cross-section while the redistribution of stresses in the surface coating of heterogeneous elasticity cross-section doesn’t cause the sudden increase of stresses. Also forming an attainable thickness of the micro-arc oxide coating on the surface of tube from aluminium alloy will be rational solution because the increase of attainable thickness of the microarc oxide coating provides an opportunity to form it on thick-walled tubes saving an acceptable, in the context of the strength, ratio of the coating area to the overall cross-section area.Micro-arc oxidation is an advanced method to form the wear resistant, resistant to corrosion, heat-shielding and electrically insulating coatings, but depending on the

  3. The effects of rest interval length on acute bench press performance: the influence of gender and muscle strength.

    Science.gov (United States)

    Ratamess, Nicholas A; Chiarello, Christina M; Sacco, Anthony J; Hoffman, Jay R; Faigenbaum, Avery D; Ross, Ryan E; Kang, Jie

    2012-07-01

    The purpose of this study was to investigate the effects of rest interval (RI) length on bench press performance in subjects with disparity in maximum strength. Two cohorts of subjects performed 3 bench press protocols in random order consisting of 3 sets of up to 10 repetitions with 75% of 1-repetition maximum (1RM) using either 1-, 2-, or 3-minute RIs between sets. In the first cohort, 22 men and women were studied to investigate gender influence. In the second cohort, 23 men were tested for 1RM bench press strength and placed into a low 1RM (mean = 80.7 ± 7.5 kg) or high 1RM (mean = 140.6 ± 11.9 kg) experimental group. The number of successful repetitions completed, average power, and velocity for each set were recorded. Women performed significantly more repetitions than men with 1-minute (26.9 ± 4.4 vs. 21.1 ± 3.5), 2-minute (29.0 ± 2.0 vs. 24.0 ± 4.5), and 3-minute (29.7 ± 1.8 vs. 25.8 ± 5.1) RIs. The magnitude of decline in average velocity and power was significantly higher in men than in women. Total number of repetitions performed was significantly greater in the low 1RM group than in the high 1RM group at 1-minute (21.6 ± 5.0 vs. 18.1 ± 2.0) and 2-minute RIs (24.2 ± 5.4 vs. 21.3 ± 2.8). Significant negative correlations were observed between 1RM bench press and total number of repetitions completed for 1- and 2-minute RIs (r = -0.558 and -0.490, respectively). These data indicate that maximal strength plays a role in bench press performance with varying RIs and suggest that shorter RIs may suffice in women to attain a specific volume.

  4. Feasibility of resistance training in adult McArdle patients: Clinical outcomes and muscle strength and mass benefits

    Directory of Open Access Journals (Sweden)

    Alfredo eSantalla

    2014-12-01

    Full Text Available We analyzed the effects of a 4-month resistance (weight lifting training program followed by a 2-month detraining period in 7 adult McArdle patients (5 female on: muscle mass (assessed by DXA, strength, serum creatine kinase (CK activity and clinical severity. Adherence to training was ≥ 84% in all patients and no major contraindication or side effect was noted during the training or strength assessment sessions. The training program had a significant impact on total and lower extremities’ lean mass (P0.05 was noted for baseline or post strength assessment values of serum CK activity, which remained essentially within the range reported in our laboratory for McArdle patients. All the patients changed to a lower severity class with training, such that none of them were in the highest disease severity class (3 after the intervention and, as such, they did not have fixed muscle weakness after training. Clinical improvements were retained, in all but one patient, after detraining, such that after detraining all patients were classed as class 1 for

  5. THE INFLUENCE OF HIP STRENGTH ON KNEE KINEMATICS DURING A SINGLE-LEGGED MEDIAL DROP LANDING AMONG COMPETITIVE COLLEGIATE BASKETBALL PLAYERS.

    Science.gov (United States)

    Suzuki, Hidetomo; Omori, Go; Uematsu, Daisuke; Nishino, Katsutoshi; Endo, Naoto

    2015-10-01

    A smaller knee flexion angle and larger knee valgus angle during weight-bearing activities have been identified as risk factors for non-contact anterior cruciate ligament (ACL) injuries. To prevent such injuries, attention has been focused on the role of hip strength in knee motion control. However, gender differences in the relationship between hip strength and knee kinematics during weight-bearing activities in the frontal plane have not been evaluated. The purpose of this study was to determine the influence of hip strength on knee kinematics in both genders during a single-legged landing task in the frontal plane. The hypotheses were that 1) subjects with a greater hip strength would demonstrate larger knee flexion and smaller knee valgus and internal rotation angles and 2) no gender differences would exist during the single-legged landing task. Forty-three Japanese collegiate basketball players (20 males, 23 females) participated in this study. Three-dimensional motion analysis was used to evaluate knee kinematics during a single-legged medial drop landing (SML). A hand-held dynamometer was used to assess hip extensor (HEXT), abductor (HAB), and external rotator (in two positions: seated position [SHER] and prone [PHER]) isometric strength. Spearman rank correlation coefficients (ρ) were determined for correlations between hip strength and knee kinematics at initial contact (IC) and peak (PK) during SML (p genders. Hip strength may, therefore, play an important role in knee motion control during sports activities, suggesting that increased hip strength may help to prevent non-contact ACL injuries in athletes of both genders. Moreover, gender-specific programs may be needed to control abnormal knee motion, as the influence of hip strength on knee kinematics may differ based on gender. 3.

  6. Positive Outcome Expectancy Mediates the Relationship Between Peer Influence and Internet Gaming Addiction Among Adolescents in Taiwan.

    Science.gov (United States)

    Wu, Jo Yung Wei; Ko, Huei-Chen; Wong, Tsui-Yin; Wu, Li-An; Oei, Tian Po

    2016-01-01

    The present study examined the role of positive outcome expectancy in the relationship between peer/parental influence and Internet gaming addiction (IGA) among adolescents in Taiwan. Two thousand, one hundred and four junior high students completed the Chen Internet Addiction Scale for IGA, Parental Influence for IGA, peer influence for IGA, and Positive Outcome Expectancy of Internet Gaming Questionnaire. Results showed that the three types of peer influences (positive attitudes toward Internet gaming, frequency of Internet game use, and invitation to play) and positive outcome expectancy were significantly and positively correlated with IGA. Moreover, peer influence was also positively correlated with positive outcome expectancy. On the other hand, positive outcome expectancy and parental influences had a low correlation. Structural equation modeling analysis revealed that positive outcome expectancy did not mediate the relationship between either type of parental influences and IGA, and only the parent's invitation to play Internet games directly predicted IGA severity. However, peers' positive attitude or the frequency of peers' Internet game use positively predicted IGA and was fully mediated through positive outcome expectancy of Internet gaming. In addition, the frequency of peers' invitation to play Internet games directly and indirectly predicted IGA severity through a partial mediation of positive outcome expectancy of Internet gaming. The overall fit of the model was adequate and was able to explain 25.0 percent of the variance. The findings provide evidence in illuminating the role of peer influences and positive outcome expectancy of Internet gaming in the process of why adolescents may develop IGA.

  7. The influence of intention and outcome on evaluations of social interaction.

    Science.gov (United States)

    Wu, Xiaoying; Hua, Rui; Yang, Zhangxiang; Yin, Jun

    2018-01-01

    Reading and making sense of social interactions between individuals is an important part of our daily social lives. Given that actions tend to be interpreted in terms of intent within the observed outcome, we investigated how intent and outcome interactively influence evaluations of social interactions. Through visual animations, intent was operationalized as an agent's (i.e., actor's) act intentionally or unintentionally having an influence on another agent (i.e., affectee). In Experiment 1, the act was helpful and the consequences brought small or great benefits to the affectee. In Experiment 2, the act was harmful and brought small or great losses to the affectee. We found that for both helpful and harmful contexts, social interaction evaluations were influenced by an interaction between the intent and outcome of the act. Specifically, great help/harm (i.e., the great-benefits or great-losses condition) was rated as a stronger social interaction than small help/harm, and the difference was larger in the intentional condition than in the unintentional condition. Furthermore, regardless of the interaction valence, the effect of the intent was larger than the effect of the outcome when evaluating social interaction. This result suggests that observers consider the intent and outcome jointly when evaluating a given social interaction, and the intent has a privileged role in this process. These findings are consistent with the idea that the intent is often deemed to be the cause driving the effect of outcome, and they help us to understand how social interactions are constructed within the action understanding system. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Thermoelastic/plastic analysis of waste-container sleeve: III. Influence of salt strength on sleeve loading. Technical memorandum report (RSI-0018)

    International Nuclear Information System (INIS)

    Pariseau, W.G.

    1975-01-01

    Three combinations of salt tensile, compressive and shear strength in linear and nonlinear yield conditions used in the axially symmetric, large displacement thermoelastic/plastic waste-container/sleeve loading estimates show no influence on the analysis. The salt remains elastic throughout the excavation and subsequent 10 year heating period. Tensile stresses are not observed, tensile strength is thus not important to the analysis even at 10 percent of the compressive strength value. Although strictly applicable only to the conditions of the analyses reported here, the capability for incorporating arbitrary strength combinations in linear or non-linear yield conditions is demonstrated. Computer plots of principal stresses and displacement fields at various stages of the excavation and heating simulation aid in the visualization of repository concept mechanics and show the possible need for additional mesh refinement for more precise stress information

  9. Influence of sand to coarse aggregate ratio on the interfacial bond strength of steel fibers in concrete for nuclear power plant

    International Nuclear Information System (INIS)

    Kim, Jung Jin; Kim, Dong Joo; Kang, Su Tae; Lee, Jang Hwa

    2012-01-01

    Highlights: ► The final goal is to develop a fiber reinforced concrete for containment buildings. ► We investigated the effect of S/a on the bond strength of steel fibers. ► Deformed steel fibers produced much higher interfacial bond strength. ► As S/a increased, twisted fiber showed a significant enhancement in bond strength. ► Smooth and hooked fiber showed no clear difference as S/a increased. - Abstract: The interfacial bond strength of three high strength steel fibers (smooth, hooked, and twisted fiber) in concrete of nuclear power plants was investigated to develop fiber reinforced concrete for containment building. Sand to aggregate ratio (S/a) was adjusted to compensate reduction in the workability due to adding fibers; the influence of S/a ratio on the interfacial bond strength was investigated. As the S/a ratio increased from 0.444 to 0.615, the bond strength of twisted steel fiber was significantly improved while smooth and hooked steel fiber showed no clear difference. The different sensitivity according to the S/a ratio results from the different pullout mechanism: twisted steel fiber generates more mechanical interaction during fiber pullout at the interface between fiber and matrix than smooth and hooked fibers. The microscopic observation by scanning electron microscope back-scattered electrons images discovered lower porosity at the interfacial transition zone between fiber and concrete with higher S/a ratio.

  10. Factors that influence the outcome of information technology projects in South Africa: An empirical investigation

    Directory of Open Access Journals (Sweden)

    Carl Marnewick

    2009-12-01

    Full Text Available Purpose: In developing countries such as South Africa, many organisations are reliant on information and communication technology (ICT to provide accurate, relevant and timely information. For organisations to obtain and sustain a competitive advantage, ICT systems are constantly implemented, upgraded, modified or replaced. These initiatives are often managed as projects. While there is an increasing amount of both financial resources and effort being spent on ICT, these projects are not always delivered within the predetermined project constraints. This implies additional time to complete, as well as additional costs, as resources are not released in time to participate in other projects. It is therefore important to understand the factors that influence the outcome of South African ICT projects relative to their original constraints. Problem Investigated: The goal of this article is to determine the factors that influence South African ICT projects, taking into consideration the fact that most current published research on this topic was done within the context of a developed country such as the USA and Europe. Design and/or methodology: The outcomes of ICT projects in South Africa as well as the factors that influence them were determined through an extensive survey. An analysis was done on the factors together with a correlation between the main factors contributing to project outcomes. The purpose of this was to establish if a factor's presence or absence influenced the eventual outcome. Findings: The factors that contribute to a successful outcome are often outside the direct control of the project manager and tend to be complex in nature. One factor that does stand out is that the alignment of projects with business objectives influences their perceived success. Originality/Value: The benefits of this article are that it firstly provides a South African perspective of current ICT project management practices, and secondly, it highlights

  11. Effect of low appendicular lean mass, grip strength, and gait speed on the functional outcome after surgery for distal radius fractures.

    Science.gov (United States)

    Roh, Young Hak; Noh, Jung Ho; Gong, Hyun Sik; Baek, Goo Hyun

    2017-12-01

    Patients with low appendicular lean mass plus slow gait speed or weak grip strength are at risk for poor functional recovery after surgery for distal radius fracture, even when they have similar radiologic outcomes. Loss of skeletal muscle mass and consequent loss in muscle function associate with aging, and this condition negatively impacts the activities of daily living and increases elderly individuals' frailty to falls. Thus, patients with low appendicular lean mass would show different functional recovery compared to those without this condition after surgery for distal radius fracture (DRF). This study compares the functional outcomes after surgery for DRF in patients with or without low appendicular lean mass plus slowness or weakness. A total of 157 patients older than 50 years of age with a DRF treated via volar plate fixation were enrolled in this prospective study. A definition of low appendicular lean mass with slowness or weakness was based on the consensus of the Asian Working Group for Sarcopenia. The researchers compared functional assessments (wrist range of motion and Michigan Hand Questionnaire [MHQ]) and radiographic assessments (radial inclination, volar tilt, ulnar variance, and articular congruity) 12 months after surgery between patients with and without low appendicular lean mass plus slowness or weakness. Multivariable regression analyses were performed to determine whether appendicular lean mass, grip strength, gait speed, patient demographic, or injury characteristics accounted for the functional outcomes. Patients with low appendicular lean mass plus slowness or weakness showed a significantly lower recovery of MHQ score than those in the control group throughout 12 months. There was no significant difference in the range of motion between the groups. The radiologic outcomes showed no significant difference between groups in terms of volar tilt, radial inclination, or ulnar variance. According to multivariable regression analysis

  12. The Influence of Reconstruction Kernel on Bone Mineral and Strength Estimates Using Quantitative Computed Tomography and Finite Element Analysis.

    Science.gov (United States)

    Michalski, Andrew S; Edwards, W Brent; Boyd, Steven K

    2017-10-17

    Quantitative computed tomography has been posed as an alternative imaging modality to investigate osteoporosis. We examined the influence of computed tomography convolution back-projection reconstruction kernels on the analysis of bone quantity and estimated mechanical properties in the proximal femur. Eighteen computed tomography scans of the proximal femur were reconstructed using both a standard smoothing reconstruction kernel and a bone-sharpening reconstruction kernel. Following phantom-based density calibration, we calculated typical bone quantity outcomes of integral volumetric bone mineral density, bone volume, and bone mineral content. Additionally, we performed finite element analysis in a standard sideways fall on the hip loading configuration. Significant differences for all outcome measures, except integral bone volume, were observed between the 2 reconstruction kernels. Volumetric bone mineral density measured using images reconstructed by the standard kernel was significantly lower (6.7%, p kernel. Furthermore, the whole-bone stiffness and the failure load measured in images reconstructed by the standard kernel were significantly lower (16.5%, p kernel. These data suggest that for future quantitative computed tomography studies, a standardized reconstruction kernel will maximize reproducibility, independent of the use of a quantitative calibration phantom. Copyright © 2017 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  13. Influence of Fracture Width on Sealability in High-Strength and Ultra-Low-Permeability Concrete in Seawater

    Directory of Open Access Journals (Sweden)

    Katsuhiko Kaneko

    2013-06-01

    Full Text Available For cementitious composites and materials, the sealing of fractures can occur in water by the precipitation of calcium compounds. In this study, the sealing behavior in a macro-fractured high-strength and ultra-low-permeability concrete (HSULPC specimen was investigated in simulated seawater using micro-focus X-ray computed tomography (CT. In particular, the influence of fracture width (0.10 and 0.25 mm on fracture sealing was investigated. Precipitation occurred mainly at the outermost parts of the fractured surface of the specimen for both fracture widths. While significant sealing was observed for the fracture width of 0.10 mm, sealing was not attained for the fracture width of 0.25 mm within the observation period (49 days. Examination of the sealed regions on the macro-fracture was performed using a three-dimensional image registration technique and applying image subtraction between the CT images of the HSULPC specimen before and after maintaining the specimen in simulated seawater. The temporal change of the sealing deposits for the fracture width of 0.10 mm was much larger than that for the fracture width of 0.25 mm. Therefore, it is concluded that the sealability of the fracture in the HSULPC is affected by the fracture width.

  14. Influence of Fracture Width on Sealability in High-Strength and Ultra-Low-Permeability Concrete in Seawater.

    Science.gov (United States)

    Fukuda, Daisuke; Nara, Yoshitaka; Hayashi, Daisuke; Ogawa, Hideo; Kaneko, Katsuhiko

    2013-06-25

    For cementitious composites and materials, the sealing of fractures can occur in water by the precipitation of calcium compounds. In this study, the sealing behavior in a macro-fractured high-strength and ultra-low-permeability concrete (HSULPC) specimen was investigated in simulated seawater using micro-focus X-ray computed tomography (CT). In particular, the influence of fracture width (0.10 and 0.25 mm) on fracture sealing was investigated. Precipitation occurred mainly at the outermost parts of the fractured surface of the specimen for both fracture widths. While significant sealing was observed for the fracture width of 0.10 mm, sealing was not attained for the fracture width of 0.25 mm within the observation period (49 days). Examination of the sealed regions on the macro-fracture was performed using a three-dimensional image registration technique and applying image subtraction between the CT images of the HSULPC specimen before and after maintaining the specimen in simulated seawater. The temporal change of the sealing deposits for the fracture width of 0.10 mm was much larger than that for the fracture width of 0.25 mm. Therefore, it is concluded that the sealability of the fracture in the HSULPC is affected by the fracture width.

  15. The interaction between non-metallic inclusions and surface roughness in fatigue failure and their influence on fatigue strength

    International Nuclear Information System (INIS)

    Saberifar, S.; Mashreghi, A.R.; Mosalaeepur, M.; Ghasemi, S.S.

    2012-01-01

    Highlights: ► The fatigue strength of a tested steel was affected by inclusions and surface notches. ► Inclusions were the main fatigue crack sources even in rough specimens. ► The stress intensity factor represented the behavior of inclusions properly. ► In rough steels the effect of inclusions was intensified by surface roughness. ► The critical inclusion size increased when surface roughness was removed. -- Abstract: In this study, the influence of non-metallic inclusions on the fatigue behavior of 30MnVS6 steel containing different inclusion sizes and surface roughness has been investigated. Scanning electron microscope (SEM) was used to examine fatigue fracture origins. It was concluded that the non-metallic inclusions were dominant fatigue crack initiation sites in both smooth and rough specimens. This was justified by the calculation of stress intensity factor generated by both surface roughness and non-metallic inclusions, based on Murakami’s model. In addition, it was found that for a given stress, the critical inclusion size could be increased by eliminating the surface roughness.

  16. Laterality and grip strength influence hand bone micro-architecture in modern humans, an HRpQCT study.

    Science.gov (United States)

    Reina, Nicolas; Cavaignac, Etienne; Trousdale, William H; Laffosse, Jean-Michel; Braga, José

    2017-06-01

    It is widely hypothesized that mechanical loading, specifically repetitive low-intensity tasks, influences the inner structure of cancellous bone. As such, there is likely a relationship between handedness and bone morphology. The aim of this study is to determine patterns in trabecular bone between dominant and non-dominant hands in modern humans. Seventeen healthy patients between 22 and 32 years old were included in the study. Radial carpal bones (lunate, capitate, scaphoid, trapezium, trapezoid, 1st, 2nd and 3rd metacarpals) were analyzed with high-resolution micro-computed tomography. Additionally, crush and pinch grip were recorded. Factorial analysis indicated that bone volume ratio, trabeculae number (Tb.N), bone surface to volume ratio (BS.BV), body weight, stature and crush grip were all positively correlated with principal components 1 and 2 explaining 78.7% of the variance. Volumetric and trabecular endostructural parameters (BV/TV, BS/BV or Tb.Th, Tb.N) explain the observed inter-individual variability better than anthropometric or clinical parameters. Factors analysis regressions showed correlations between these parameters and the dominant side for crush strength for the lunate (r 2 = 0.640, P modern human wrist. © 2017 Anatomical Society.

  17. Modelling and simulation of the influence of forming processes on the structural behavior of high strength steels

    International Nuclear Information System (INIS)

    Gelin, J.C.; Thibaud, S.; Boudeau, N.

    2005-01-01

    The paper first describes experiments and modeling concerning the identification of material behavior for high strength steels with phase transformations associated to plastic deformation. The experiments consist of tensile and bulging tests carried out on 316L stainless steels and TRIP 700 steels used in automotive industry. These experiments have permitted to determine the hardening curves of such materials vs. the martensite volume fraction associated to plastic deformation. It has been demonstrated that the stress triaxiality has a major role in the martenstic transformation and a model is proposed to define the flow stress vs. effective strain accounting planar anisotropy and variation of martenstic volume fraction. Then a plasticity model has been proposed in an anisotropic form and the related flow rules have been defined. The resulting model has been implemented in different finite elements software, and applied in numerical simulations of stamping and hydroforming of typical components to prove the effects of forming processes on the resulting properties of the components. Finally, the structural behavior of the resulting components is investigated and the effects of forming processes on the resulting structural behaviour are analyzed. Two cases are presented, one concerns the deep drawing of a cylindrical cup and the other concerns the stamping of a closed U channel used as a structural part for crash frames. Is has been clearly proved that the variation of martensite volume fraction arising during processing has a strong influence on the resulting behaviour of the parts considering springback and crash resistance

  18. Replay of conditioned stimuli during late REM and stage N2 sleep influences affective tone rather than emotional memory strength.

    Science.gov (United States)

    Rihm, Julia S; Rasch, Björn

    2015-07-01

    Emotional memories are reprocessed during sleep, and it is widely assumed that this reprocessing occurs mainly during rapid eye movement (REM) sleep. In support for this notion, vivid emotional dreams occur mainly during REM sleep, and several studies have reported emotional memory enhancement to be associated with REM sleep or REM sleep-related parameters. However, it is still unknown whether reactivation of emotional memories during REM sleep strengthens emotional memories. Here, we tested whether re-presentation of emotionally learned stimuli during REM sleep enhances emotional memory. In a split-night design, participants underwent Pavlovian conditioning after the first half of the night. Neutral sounds served as conditioned stimuli (CS) and were either paired with a negative odor (CS+) or an odorless vehicle (CS-). During sound replay in subsequent late REM or N2 sleep, half of the CS+ and half of the CS- were presented again. In contrast to our hypothesis, replay during sleep did not affect emotional memory as measured by the differentiation between CS+ and CS- in expectancy, arousal and valence ratings. However, replay unspecifically decreased subjective arousal ratings of both emotional and neutral sounds and increased positive valence ratings also for both CS+ and CS- sounds, respectively. These effects were slightly more pronounced for replay during REM sleep. Our results suggest that re-exposure to previously conditioned stimuli during late sleep does not affect emotional memory strength, but rather influences the affective tone of both emotional and neutral memories. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Does the Rotator Cuff Tear Pattern Influence Clinical Outcomes After Surgical Repair?

    Science.gov (United States)

    Watson, Scott; Allen, Benjamin; Robbins, Chris; Bedi, Asheesh; Gagnier, Joel J; Miller, Bruce

    2018-03-01

    Limited literature exists regarding the influence of rotator cuff tear morphology on patient outcomes. To determine the effect of rotator cuff tear pattern (crescent, U-shape, L-shape) on patient-reported outcomes after rotator cuff repair. Cohort study; Level of evidence, 3. Patients undergoing arthroscopic repair of known full-thickness rotator cuff tears were observed prospectively at regular intervals from baseline to 1 year. The tear pattern was classified at the time of surgery as crescent, U-shaped, or L-shaped. Primary outcome measures were the Western Ontario Rotator Cuff Index (WORC), the American Shoulder and Elbow Surgeons (ASES), and a visual analog scale (VAS) for pain. The tear pattern was evaluated as the primary predictor while controlling for variables known to affect rotator cuff outcomes. Mixed-methods regression and analysis of variance (ANOVA) were used to examine the effects of tear morphology on patient-reported outcomes after surgical repair from baseline to 1 year. A total of 82 patients were included in the study (53 male, 29 female; mean age, 58 years [range, 41-75 years]). A crescent shape was the most common tear pattern (54%), followed by U-shaped (25%) and L-shaped tears (21%). There were no significant differences in outcome scores between the 3 groups at baseline. All 3 groups showed statistically significant improvement from baseline to 1 year, but analysis failed to show any predictive effect in the change in outcome scores from baseline to 1 year for the WORC, ASES, or VAS when tear pattern was the primary predictor. Further ANOVA also failed to show any significant difference in the change in outcome scores from baseline to 1 year for the WORC ( P = .96), ASES ( P = .71), or VAS ( P = .86). Rotator cuff tear pattern is not a predictor of functional outcomes after arthroscopic rotator cuff repair.

  20. Influence of local surface texture by tool impression on the self piercing\\ud riveting process and the static lap shear strength

    OpenAIRE

    Li, Dezhi

    2017-01-01

    To increase fuel efficiency and reduce emission, aluminium alloys have been increasingly used in automotive body-in-white structures for lightweighting. Due to its advantages over some of the more traditional joining technologies, self-piercing riveting (SPR) has been widely used for these lightweight structures. Research has showed that friction is a very important factor that influences both the riveting process and joint strength for SPR, but these influences have not been fully understood...

  1. Influence of Immersion Conditions on The Tensile Strength of Recycled Kevlar®/Polyester/Low-Melting-Point Polyester Nonwoven Geotextiles through Applying Statistical Analyses

    Directory of Open Access Journals (Sweden)

    Jing-Chzi Hsieh

    2016-05-01

    Full Text Available The recycled Kevlar®/polyester/low-melting-point polyester (recycled Kevlar®/PET/LPET nonwoven geotextiles are immersed in neutral, strong acid, and strong alkali solutions, respectively, at different temperatures for four months. Their tensile strength is then tested according to various immersion periods at various temperatures, in order to determine their durability to chemicals. For the purpose of analyzing the possible factors that influence mechanical properties of geotextiles under diverse environmental conditions, the experimental results and statistical analyses are incorporated in this study. Therefore, influences of the content of recycled Kevlar® fibers, implementation of thermal treatment, and immersion periods on the tensile strength of recycled Kevlar®/PET/LPET nonwoven geotextiles are examined, after which their influential levels are statistically determined by performing multiple regression analyses. According to the results, the tensile strength of nonwoven geotextiles can be enhanced by adding recycled Kevlar® fibers and thermal treatment.

  2. The influence of age, sex, bulb position, visual feedback, and the order of testing on maximum anterior and posterior tongue strength and endurance in healthy belgian adults.

    Science.gov (United States)

    Vanderwegen, Jan; Guns, Cindy; Van Nuffelen, Gwen; Elen, Rik; De Bodt, Marc

    2013-06-01

    This study collected data on the maximum anterior and posterior tongue strength and endurance in 420 healthy Belgians across the adult life span to explore the influence of age, sex, bulb position, visual feedback, and order of testing. Measures were obtained using the Iowa Oral Performance Instrument (IOPI). Older participants (more than 70 years old) demonstrated significantly lower strength than younger persons at the anterior and the posterior tongue. Endurance remains stable throughout the major part of life. Gender influence remains significant but minor throughout life, with males showing higher pressures and longer endurance. The anterior part of the tongue has both higher strength and longer endurance than the posterior part. Mean maximum tongue pressures in this European population seem to be lower than American values and are closer to Asian results. The normative data can be used for objective assessment of tongue weakness and subsequent therapy planning of dysphagic patients.

  3. Does source of funding and conflict of interest influence the outcome and quality of spinal research?

    Science.gov (United States)

    Amiri, Amir Reza; Kanesalingam, Kavitha; Cro, Suzie; Casey, Adrian T H

    2014-02-01

    There has been longstanding controversy surrounding the influence of funding source on the conduct and outcome of medical research. In 2011, a systematic review of the use of recombinant bone morphogenetic protein-2 revealed underreporting of unfavorable outcomes in some industry-sponsored trials. We hypothesize that Industrial funding and the presence of potential conflict of interest will be associated with low levels of evidence (LOE) and greater proportions of favorable outcomes in spinal research. The aim of this study is to investigate the association between funding source and potential conflict of interest on the LOE and study outcome in the current spinal research. Systematic review of all the spinal publications in five leading spinal, orthopedics, neurosurgery, and general medical journals during 2010 (print and online). Supplements were included. Outcome and the LOE of research papers. Two reviewers independently assessed all publications. Commentaries, editorials, letters, open operating theatres, case reports, narrative reviews, and study protocols were excluded. The self-reported potential conflict of interest and type of funding was extracted from each paper. Funding type was classified as foundation, industry, public, intramural, multiple (including industry), multiple (without industry), and unfunded. The outcome of each study was classified as favorable, unfavorable, equivocal, or not applicable. Clinical publications were ranked using the LOE guidelines produced by the Oxford Center for Evidence-Based Medicine. Overall, 1356 papers were analyzed, out of which 864 were suitable for LOE grading. There was good interobserver reliability for assignment of LOE grade, κ=0.897 (psource of funding (psource and study outcome (p=.01). The proportion of industry-funded studies with favorable outcomes (88%) was higher than that of publicly and foundation-funded studies (73% and 74%, respectively). The associated odds ratio for reporting favorable outcomes

  4. Changes in the flexural strength of engineering ceramics after high temperature sodium corrosion test. Influence after sodium exposure for 1000 hours

    International Nuclear Information System (INIS)

    Hayashi, Kazunori; Tachi, Yoshiaki; Kano, Shigeki; Hirakawa, Yasushi; Komine, Ryuji; Yoshida, Eiichi

    1998-02-01

    Engineering ceramics have excellent properties such as high strength, high hardness and high heat resistance compared with metallic materials. To apply the ceramic in fast reactor environment, it is necessary to evaluate the sodium compatibility and the influence of sodium on the mechanical properties of ceramics. In this study, the influence of high temperature sodium on the mechanical properties of sintered ceramics of conventional and high purity Al 2 O 3 , SiC, SiAlON, AlN and unidirectional solidified ceramics of Al 2 O 3 /YAG eutectic composite were investigated by means of flexure tests. Test specimens were exposed in liquid sodium at 823K and 923K for 3.6Ms. There were no changes in the flexural strength of the conventional and high purity Al 2 O 3 , AlN and Al 2 O 3 /YAG eutectic composite after the sodium exposure at 823K. On the contrary, the decrease in the flexural strength was observed in SiC and SiAlON. After the sodium exposure at 923K, there were also no changes in the flexural strength of AlN and Al 2 O 3 /YAG eutectic composite. In the conventional and high purity Al 2 O 3 and SiC, the flexural strength decreased and signs of grain boundary corrosion were detected by surface observation. The flexural strength of SiAlON after the sodium exposure at 923K increased instead of severe corrosion. In the specimens those showed no changes in the flexural strength, further exposure in sodium is needed to verify whether the mechanical properties degrade or not. For SiAlON, it is necessary to clarify the reason for the increased strength after the sodium exposure at 923K. (author)

  5. Teammates and social influence affect weight loss outcomes in a team-based weight loss competition.

    Science.gov (United States)

    Leahey, Tricia M; Kumar, Rajiv; Weinberg, Brad M; Wing, Rena R

    2012-07-01

    Team-based internet interventions are increasing in popularity as a way of promoting weight loss in large numbers of individuals. Given that social networks influence health behavior change, this study investigated the effects of teammates and social influence on individual weight loss during a team-based weight loss competition. Shape Up Rhode Island (SURI) 2009 was a 12-week online program open to adult residents of Rhode Island. Participants joined with a team and competed with other teams on weight loss and/or physical activity. Overweight/obese (OW/OB) individuals (N = 3,330; 76% female; age = 46.1 ± 10.8; BMI = 31.2 ± 5.3 kg/m(2)), representing 987 teams, completed the weight loss program. Multilevel modeling was used to examine whether weight loss clustered among teammates and whether percentage of teammates in the weight loss division and reported teammate influence on weight loss were associated with individual weight outcomes. OW/OB completers reported losing 4.2 ± 3.4% of initial body weight. Weight loss was similar among teammates (intraclass correlation coefficient (ICC) = 0.10, P social influence for weight loss were associated with greater percent weight loss (P's ≤ 0.002). Similarly, achieving a clinically significant (5%) weight loss tended to cluster within teams (ICC = 0.09; P social influence for weight loss were associated with increased likelihood of achieving a 5% weight loss (odds ratio (OR) = 1.06; OR = 1.20, respectively). These results suggest that teammates affect weight loss outcomes during a team-based intervention. Harnessing and maximizing teammate influence for weight loss may enhance weight outcomes in large-scale team-based programs.

  6. Aquatic Therapy Improves Outcomes for Subacute Stroke Patients by Enhancing Muscular Strength of Paretic Lower Limbs Without Increasing Spasticity: A Randomized Controlled Trial.

    Science.gov (United States)

    Zhang, Yue; Wang, Yi-Zhao; Huang, Li-Ping; Bai, Bei; Zhou, Shi; Yin, Miao-Miao; Zhao, Hua; Zhou, Xiao-Na; Wang, Hong-Tu

    2016-11-01

    The aim of this study was to evaluate the effects of an aquatic exercise program designed to enhance muscular strength in paretic lower limbs in subacute stroke patients. Thirty-six subacute stroke patients were randomly divided to a conventional or an aquatic group (n = 18 each). Outcome measures were assessed at baseline and after 8 wks of training. For the paretic lower limbs, maximum isometric voluntary contraction strength of the rectus femoris and biceps femoris caput longus and the tibialis anterior and lateral gastrocnemius was measured. Cocontraction ratios during knee extension and flexion and ankle dorsiflexion and plantarflexion were calculated respectively. In addition, Modified Ashworth Scale, Functional Ambulation Category, and Barthel Index were assessed. Compared with the conventional intervention, the aquatic intervention resulted in significantly higher knee extension (P = 0.002) and ankle plantarflexion torque (P = 0.002), accompanied with a significantly lower knee extension cocontraction ratio in the paretic limb (P = 0.000). Functional Ambulation Category (P = 0.009) and Barthel Index (P = 0.024) were greater in aquatic group than conventional group posttreatment. Modified Ashworth Scale scores did not show any differences between groups. Aquatic exercise enhanced muscle strength in paretic lower limbs and improved muscle cocontraction without increasing spasticity in subacute stroke patients.

  7. Influence of xylem ray integrity and degree of polymerization on bending strength of beech wood decayed by Pleurotus ostreatus and Trametes versicolor

    Science.gov (United States)

    Ehsan Bari; Reza Oladi; Olaf Schmidt; Carol A. Clausen; Katie Ohno; Darrel D. Nicholas; Mehrdad Ghodskhah Daryaei; Maryam Karim

    2015-01-01

    The scope of this research was to evaluate the influence of xylem ray (XR) and degree of polymerization (DP) of holocellulose in Oriental beech wood (Fagus orientalis Lipsky.) on impact bending strength against two white-rot fungi. Beech wood specimens, exposed to Pleurotus ostreatus and Trametes versicolor, were evaluated for...

  8. Transport and Retention of TiO2 Rutile Nanoparticles in Saturated Porous Media: Influence of Solution pH, Ionic Strength, and the Presence of Humic Acid

    Science.gov (United States)

    The influence of solution pH, ionic strength, and varying concentrations of the Suwannee River Humic Acid (SRHA) on the transport of titanium dioxide (TiO2, rutile) nanoparticle aggregates (nTiO2) in saturated porous media was investigated through systematically examining the tra...

  9. Impact of Burnout on Organizational Outcomes, the Influence of Legal Demands: The Case of Ecuadorian Physicians

    Directory of Open Access Journals (Sweden)

    Paola Ochoa

    2018-05-01

    Full Text Available Interest in burnout has developed extensively worldwide, but there is scarce the literature regarding the consequences that new legal demands have on burnout and on organizational outcomes in physicians. The global context of the medical profession has been characterized in the recent years by changes in the employment patterns, profound intensification of work, and increment of labor flexibility. In this context, the study aims to analyze the influence of burnout on organizational outcomes in physicians, depending on new legal demands perception in Ecuador. Regarding the method, the research was cross sectional and in the first stage, studied the psychometric characteristics, validity and reliability of the instrument to assess burnout through a series of confirmatory factor analyses (CFA. In a second part, we assessed, the robustness of the model of causal relations between the burnout dimensions and organizational outcomes. We carried out a series of path analysis, structural equation model. The study was accomplished in five hospitals and the sample was incidental, comprising 435 physicians from Ecuador. We divided the group in two subcategories, Sample A, composed by participants that considered that new Criminal Code (COIP affects them and the Sample B, the group of physicians who believed that the COIP does not affect them. Burnout was assessed with the Spanish adaptation of the Maslach Burnout Inventory (MBI, the Organizational outcomes were measured with a seven-item self-report questionnaire, and we included an item regarding to the influence of new Criminal Code. We formulated four hypotheses, that considered that physicians who believed that the COIP affect them experience a greater negative influence of burnout on organizational outcomes. The results indicated that the group of physicians who believed that the COIP affects them (Sample A experienced a greater negative influence of cynicism on productivity than Sample B. Moreover

  10. Impact of Burnout on Organizational Outcomes, the Influence of Legal Demands: The Case of Ecuadorian Physicians.

    Science.gov (United States)

    Ochoa, Paola

    2018-01-01

    Interest in burnout has developed extensively worldwide, but there is scarce the literature regarding the consequences that new legal demands have on burnout and on organizational outcomes in physicians. The global context of the medical profession has been characterized in the recent years by changes in the employment patterns, profound intensification of work, and increment of labor flexibility. In this context, the study aims to analyze the influence of burnout on organizational outcomes in physicians, depending on new legal demands perception in Ecuador. Regarding the method, the research was cross sectional and in the first stage, studied the psychometric characteristics, validity and reliability of the instrument to assess burnout through a series of confirmatory factor analyses (CFA). In a second part, we assessed, the robustness of the model of causal relations between the burnout dimensions and organizational outcomes. We carried out a series of path analysis, structural equation model. The study was accomplished in five hospitals and the sample was incidental, comprising 435 physicians from Ecuador. We divided the group in two subcategories, Sample A, composed by participants that considered that new Criminal Code (COIP) affects them and the Sample B, the group of physicians who believed that the COIP does not affect them. Burnout was assessed with the Spanish adaptation of the Maslach Burnout Inventory (MBI), the Organizational outcomes were measured with a seven-item self-report questionnaire, and we included an item regarding to the influence of new Criminal Code. We formulated four hypotheses, that considered that physicians who believed that the COIP affect them experience a greater negative influence of burnout on organizational outcomes. The results indicated that the group of physicians who believed that the COIP affects them (Sample A) experienced a greater negative influence of cynicism on productivity than Sample B. Moreover, the lack of

  11. The Influence of No Fault Compensation on Functional Outcomes After Lumbar Spine Fusion.

    Science.gov (United States)

    Montgomery, Alexander Sheriff; Cunningham, John Edward; Robertson, Peter Alexander

    2015-07-15

    compared with the dramatically inferior outcomes for these patients under other worker's compensation systems, suggest that the system of compensation has a major influence on patient outcomes, and that change of compensation to a universal no fault system is beneficial for patients undergoing lumbar fusion surgery. 2.

  12. Influence of Race, Ethnicity and Social Determinants of Health on Diabetes Outcomes.

    Science.gov (United States)

    Walker, Rebekah J; Strom Williams, Joni; Egede, Leonard E

    2016-04-01

    There is strong evidence that race, ethnicity and social determinants of health significantly influence outcomes for patients with diabetes. A better understanding of the mechanisms of these relationships or associations would improve development of cost-effective, culturally tailored programs for patients with diabetes. This article reviews the current state of the literature on the influence of race and ethnicity and social determinants of health on process of care, quality of care and outcomes for diabetes, with particular emphasis on the rural South to give an overview of the state of the literature. The literature review shows that racial or ethnic differences in the clinical outcomes for diabetes, including glycemic, blood pressure (BP) and lipid control, continue to persist. In addition, the literature review shows that the role of social determinants of health on outcomes, and the possible role these determinants play in disparities have largely been ignored. Psychosocial factors, such as self-efficacy, depression, social support and perceived stress, show consistent associations with self-care, quality of life and glycemic control. Neighborhood factors, such as food insecurity, social cohesion and neighborhood esthetics have been associated with glycemic control. Perceived discrimination has also been associated with self-care and the psychological component of quality of life. Healthcare professionals need to be skilled in assessing social determinants of health and taking them into consideration in clinical care. In addition, more research is needed to identify the separate and combined influence of race and ethnicity and social determinants of health on process of care, quality of care and outcomes in diabetes, especially in the South, where the burden of disease is particularly high. Copyright © 2016 Southern Society for Clinical Investigation. All rights reserved.

  13. The Human Skin Microbiome Associates with the Outcome of and Is Influenced by Bacterial Infection

    OpenAIRE

    van Rensburg, Julia J.; Lin, Huaiying; Gao, Xiang; Toh, Evelyn; Fortney, Kate R.; Ellinger, Sheila; Zwickl, Beth; Janowicz, Diane M.; Katz, Barry P.; Nelson, David E.; Dong, Qunfeng; Spinola, Stanley M.

    2015-01-01

    ABSTRACT The influence of the skin microbiota on host susceptibility to infectious agents is largely unexplored. The skin harbors diverse bacterial species that may promote or antagonize the growth of an invading pathogen. We developed a human infection model for Haemophilus ducreyi in which human volunteers are inoculated on the upper arm. After inoculation, papules form and either spontaneously resolve or progress to pustules. To examine the role of the skin microbiota in the outcome of H. ...

  14. The influence of caregiver depression on adolescent mental health outcomes: findings from refugee settlements in Uganda

    OpenAIRE

    Meyer, Sarah R; Steinhaus, Mara; Bangirana, Clare; Onyango-Mangen, Patrick; Stark, Lindsay

    2017-01-01

    Background Family-level predictors, including caregiver depression, are considered important influences on adolescent mental health. Adolescent depression and anxiety in refugee settings is known to be a significant public health concern, yet there is very limited literature from humanitarian settings focusing on the relationship between caregiver mental health and adolescent mental health. In the context of a larger study on child protection outcomes in refugee settings, researchers explored...

  15. Leader Affect and Leadership Effectiveness: How leader affective displays influence follower outcomes

    OpenAIRE

    Visser, Victoria

    2013-01-01

    textabstractThe aim of this dissertation is to uncover the relationship between leader affective displays and leadership effectiveness. Five empirical studies were conducted to test the influence of several leader affective displays on different follower outcomes that indicate leadership effectiveness. The results showed that leader happy displays enhance followers’ creative performance, whereas leader sad displays enhance followers’ analytical performance. In addition, a leader displaying ha...

  16. Autonomy, Affiliation, and Ability: Relative Salience of Factors that Influence Online Learner Motivation and Learning Outcomes

    Directory of Open Access Journals (Sweden)

    Kuan-Chung Chen

    2010-03-01

    Full Text Available Autonomy, affiliation, and ability appear as main factors that influence online learners‟ motivation and learning outcomes, however, the relative salience of these three factors remains unclear in the online learning literature. Drawing on Deci and Ryan‟s self-determination theory, this study sought to bridge this gap by investigating the relative salience of perceived autonomy, affiliation, and ability on learner motivation and learning outcomes in two special education online programs (N = 262. This study found that the most salient predictor varied from categories of motivation and learning outcomes, and the number of significant predictors increased by participants‟ level of motivation/self-determination. Results of this study provide implications for online learner support.

  17. The Influence of Posttraumatic Stress Disorder on Treatment Outcomes of Patients With Borderline Personality Disorder.

    Science.gov (United States)

    Boritz, Tali; Barnhart, Ryan; McMain, Shelley F

    2016-06-01

    The aim of this study was to determine the influence of posttraumatic stress disorder (PTSD) on treatment outcomes in patients with borderline personality disorder (BPD). Participants were 180 individuals diagnosed with BPD enrolled in a randomized controlled trial that compared the clinical and cost effectiveness of dialectical behavior therapy (DBT) and general psychiatric management (GPM). Multilevel linear models and generalized linear models were used to compare clinical outcomes of BPD patients with and without PTSD. BPD patients with comorbid PTSD reported significantly higher levels of global psychological distress at baseline and end of treatment compared to their non-PTSD counterparts. Both groups evidenced comparable rates of change on suicide attempts and non-suicidal self-injury (NSSI), global psychological distress, and BPD symptoms over the course of treatment and post-treatment follow-up. DBT and GPM were effective for BPD patients with and without PTSD across a broad range of outcomes.

  18. Systematic review: Do patient expectations influence treatment outcomes in total knee and total hip arthroplasty?

    Directory of Open Access Journals (Sweden)

    Haanstra Tsjitske M

    2012-12-01

    Full Text Available Abstract Objective This systematic review aims to summarise all the available evidence related to the association between pre-operative patient expectations (outcome expectations, process expectations and self efficacy expectations and 5 different treatment outcomes (overall improvement, pain, function, stiffness and satisfaction in patients with total knee or total hip arthroplasty at three different follow-op periods (>6 weeks; >6 weeks- ≤6 months; >6 months. Methods English and Dutch language articles were identified through PubMed, EMBASE.com, PsycINFO, CINAHL and The Cochrane Library from inception to September 2012. Articles assessing the association between pre-operative patient expectations and treatment outcomes for TKA/THA in either adjusted or unadjusted analysis were included. Two reviewers, working independently, determined eligibility, rated methodological quality and extracted data on study design, population, expectation measurements, outcome measurements and strength of the associations. Methodological quality was rated by the same reviewers on a 19 item scale. The scores on the quality assessment were taken into account when drawing final conclusions. Results The search strategy generated 2252 unique references, 18 articles met inclusion criteria. Scores on the methodological quality assessment ranged between 6% and 79%. Great variety was seen in definitions and measurement methods of expectations. No significant associations were found between patient expectations and overall improvement, satisfaction and stiffness. Both significant positive and non-significant associations were found for the association between expectations and pain and function. Conclusions There was no consistency in the association between patients’ pre-operative expectations and treatment outcomes for TKA and THA indentified in this systematic review. There exists a need for a sound theoretical framework underlying the construct of

  19. The influence of radiotherapy on cosmetic outcome after breast conservative surgery

    International Nuclear Information System (INIS)

    McCormick, Beryl; Sacchini, Virgilio; Luini, Alberto; Agresti, Roberto; Greco, Marco; Manzari, Antonella; Mariani, Luigi; Zucali, Roberto

    1995-01-01

    Purpose: The influence of radiotherapy in the cosmetic outcome after conservative surgery for breast cancer was evaluated using an objective method of calculating the asymmetry between the two breasts. Methods and Materials: One hundred and one patients treated with the same conservative surgery were evaluated for cosmetic outcome. Sixty-one of them received external radiotherapy (50 + 10 Gy) to the residual breast; the remaining 40 underwent surgery only. The aspect of the patients' breasts was objectively assessed for symmetry by means of a computerized technique. A subjective assessment of the cosmetic outcome was performed both by physician and patient. These objective and subjective assessments were compared in the two groups treated with or without radiotherapy. Results: The results obtained did not show significant differences in terms of cosmetic outcome in the two groups. Skin telangectasia was noted in two radiotherapy patients, while hypertrophic breast scars were only noted in six nonirradiated patients. Conclusions: We found that standard radiotherapy does not seem to influence the symmetry and the cosmetic results in breast conservative treatment when compared to a similar group of patients with the same quadrantectomy procedure and no radiotherapy

  20. Influence of porosity and groundmass crystallinity on dome rock strength: a case study from Mt. Taranaki, New Zealand

    Science.gov (United States)

    Zorn, Edgar U.; Rowe, Michael C.; Cronin, Shane J.; Ryan, Amy G.; Kennedy, Lori A.; Russell, James K.

    2018-04-01

    Lava domes pose a significant hazard to infrastructure, human lives and the environment when they collapse. Their stability is partly dictated by internal mechanical properties. Here, we present a detailed investigation into the lithology and composition of a Rocks with variable porosity and groundmass crystallinity were compared using measured compressive and tensile strength, derived from deformation experiments performed at room temperature and low (3 MPa) confining pressures. Based on data obtained, porosity exerts the main control on rock strength and mode of failure. High porosity (> 23%) rocks show low rock strength (rocks (5-23%) exhibit higher measured rock strengths (up to 278 MPa) and brittle failure. Groundmass crystallinity, porosity and rock strength are intercorrelated. High groundmass crystal content is inversely related to low porosity, implying crystallisation and degassing of a slowly undercooled magma that experienced rheological stiffening under high pressures deeper within the conduit. This is linked to a slow magma ascent rate and results in a lava dome with higher rock strength. Samples with low groundmass crystallinity are associated with higher porosity and lower rock strength, and represent magma that ascended more rapidly, with faster undercooling, and solidification in the upper conduit at low pressures. Our experimental results show that the inherent strength of rocks within a growing dome may vary considerably depending on ascent/emplacement rates, thus significantly affecting dome stability and collapse hazards.

  1. The influence of high heat input and inclusions control for rare earth on welding in low alloy high strength steel

    Science.gov (United States)

    Chu, Rensheng; Mu, Shukun; Liu, Jingang; Li, Zhanjun

    2017-09-01

    In the current paper, it is analyzed for the influence of high heat input and inclusions control for rare earth on welding in low alloy high strength steel. It is observed for the structure for different heat input of the coarse-grained area. It is finest for the coarse grain with the high heat input of 200 kJ / cm and the coarse grain area with 400 kJ / cm is the largest. The performance with the heat input of 200 kJ / cm for -20 °C V-shaped notch oscillatory power is better than the heat input of 400 kJ / cm. The grain structure is the ferrite and bainite for different holding time. The grain structure for 5s holding time has a grain size of 82.9 μm with heat input of 200 kJ/cm and grain size of 97.9 μm for 10s holding time. For the inclusions for HSLA steel with adding rare earth, they are Al2O3-CaS inclusions in the Al2O3-CaS-CaO ternary phase diagram. At the same time, it can not be found for low melting calcium aluminate inclusions compared to the inclusions for the HSLA steel without rare earth. Most of the size for the inclusions is between 1 ~ 10μm. The overall grain structure is smaller and the welding performance is more excellent for adding rare earth.

  2. Influence of loading and unloading velocity of confining pressure on strength and permeability characteristics of crystalline sandstone

    Science.gov (United States)

    Zhang, Dong-ming; Yang, Yu-shun; Chu, Ya-pei; Zhang, Xiang; Xue, Yan-guang

    2018-06-01

    The triaxial compression test of crystalline sandstone under different loading and unloading velocity of confining pressure is carried out by using the self-made "THM coupled with servo-controlled seepage apparatus for containing-gas coal", analyzed the strength, deformation and permeability characteristics of the sample, the results show that: with the increase of confining pressures loading-unloading velocity, Mohr's stress circle center of the specimen shift to the right, and the ultimate intensity, peak strain and residual stress of the specimens increase gradually. With the decrease of unloading velocity of confining pressure, the axial strain, the radial strain and the volumetric strain of the sample decrease first and then increases, but the radial strain decreases more greatly. The loading and unloading of confining pressure has greater influence on axial strain of specimens. The deformation modulus decreases rapidly with the increase of axial strain and the Poisson's ratio decreases gradually at the initial stage of loading. When the confining pressure is loaded, the deformation modulus decrease gradually, and the Poisson's ratio increases gradually. When the confining pressure is unloaded, the deformation modulus increase gradually, and the Poisson's ratio decreases gradually. When the specimen reaches the ultimate intensity, the deformation modulus decreases rapidly, while the Poisson's ratio increases rapidly. The fitting curve of the confining pressure and the deformation modulus and the Poisson's ratio in accordance with the distribution of quadratic polynomial function in the loading-unloading confining pressure. There is a corresponding relationship between the evolution of rock permeability and damage deformation during the process of loading and unloading. In the late stage of yielding, the permeability increases slowly, and the permeability increases sharply after the rock sample is destroyed. Fitting the permeability and confining pressure

  3. Influence of alloy microstructure on the microshear bond strength of basic alloys to a resin luting cement.

    Science.gov (United States)

    Bauer, José; Costa, José Ferreira; Carvalho, Ceci Nunes; Souza, Douglas Nesadal de; Loguercio, Alessandro Dourado; Grande, Rosa Helena Miranda

    2012-01-01

    The aim of this study was to evaluate the influence of microstructure and composition of basic alloys on their microshear bond strength (µSBS) to resin luting cement. The alloys used were: Supreme Cast-V (SC), Tilite Star (TS), Wiron 99 (W9), VeraBond II (VBII), VeraBond (VB), Remanium (RM) and IPS d.SIGN 30 (IPS). Five wax patterns (13 mm in diameter and 4mm height) were invested, and cast in a centrifugal casting machine for each basic alloy. The specimens were embedded in resin, polished with a SiC paper and sandblasted. After cleaning the metal surfaces, six tygon tubes (0.5 mm height and 0.75 mm in diameter) were placed on each alloy surface, the resin cement (Panavia F) was inserted, and the excess was removed before light-curing. After storage (24 h/37°C), the specimens were subjected to µSBS testing (0.5 mm/min). The data were subjected to a one-way repeated measures analysis of variance and Turkey's test (α=0.05). After polishing, their microstructures were revealed with specific conditioners. The highest µSBS (mean/standard deviation in MPa) were observed in the alloys with dendritic structure, eutectic formation or precipitation: VB (30.6/1.7), TS (29.8/0.9), SC (30.6/1.7), with the exception of IPS (31.1/0.9) which showed high µSBS but no eutectic formation. The W9 (28.1/1.5), VBII (25.9/2.0) and RM (25.9/0.9) showed the lowest µSBS and no eutectic formation. It seems that alloys with eutectic formation provide the highest µSBS values when bonded to a light-cured resin luting cement.

  4. Beneath the veil: Plant growth form influences the strength of species richness-productivity relationships in forests

    Science.gov (United States)

    Oberle, B.; Grace, J.B.; Chase, J.M.

    2009-01-01

    Aim: Species richness has been observed to increase with productivity at large spatial scales, though the strength of this relationship varies among functional groups. In forests, canopy trees shade understorey plants, and for this reason we hypothesize that species richness of canopy trees will depend on macroclimate, while species richness of shorter growth forms will additionally be affected by shading from the canopy. In this study we test for differences in species richness-productivity relationships (SRPRs) among growth forms (canopy trees, shrubs, herbaceous species) in small forest plots. Location: We analysed 231 plots ranging from 34.0?? to 48.3?? N latitude and from 75.0?? to 124.2?? W longitude in the United States. Methods: We analysed data collected by the USDA Forest Inventory and Analysis program for plant species richness partitioned into different growth forms, in small plots. We used actual evapotranspiration as a macroclimatic estimate of regional productivity and calculated the area of light-blocking tissue in the immediate area surrounding plots for an estimate of the intensity of local shading. We estimated and compared SRPRs for different partitions of the species richness dataset using generalized linear models and we incorporated the possible indirect effects of shading using a structural equation model. Results: Canopy tree species richness increased strongly with regional productivity, while local shading primarily explained the variation in herbaceous plant richness. Shrub species richness was related to both regional productivity and local shading. Main conclusions: The relationship between total forest plant species richness and productivity at large scales belies strong effects of local interactions. Counter to the pattern for overall richness, we found that understorey herbaceous plant species richness does not respond to regional productivity gradients, and instead is strongly influenced by canopy density, while shrub species

  5. Influence of successive badminton matches on muscle strength, power, and body-fluid balance in elite players.

    Science.gov (United States)

    Abian-Vicen, Javier; Castanedo, Adrián; Abian, Pablo; Gonzalez-Millan, Cristina; Salinero, Juan José; Del Coso, Juan

    2014-07-01

    The aim was to analyze the influence of competitive round on muscle strength, body-fluid balance, and renal function in elite badminton players during a real competition. Body mass, jump height during a countermovement jump, handgrip force, and urine samples were obtained from 13 elite badminton players (6 men and 7 women) before and after the 2nd-round and quarterfinal matches of the national Spanish badminton championship. Sweat rate was determined by using prematch-to-postmatch body-mass change and by weighing individually labeled fluid bottles. Sweat rates were 1.04 ± 0.62 and 0.98 ± 0.43 L/h, while rehydration rate was 0.69 ± 0.26 and 0.91 ± 0.52 L/h for the 2nd round and quarterfinals, respectively. Thus, dehydration was 0.47% ± 1.03% after the 2nd round and 0.23% ± 0.43% after the quarterfinals. There were no differences in prematch-to-postmatch jump height, but jump height was reduced from 37.51 ± 8.83 cm after the 2nd-round game to 34.82 ± 7.37 cm after the quarterfinals (P badminton competition were effective to prevent dehydration. A badminton match did not affect jump height or handgrip force, but jump height was progressively reduced by the competitive round. Badminton players' renal responses reflected diminished renal flux due to the high-intensity nature of this racket sport.

  6. [Different strength intermittent treadmill training of growth period rats and related bone metabolism of the hormone influence].

    Science.gov (United States)

    Xie, Shun-cheng; Ma, Xue-jun; Guo, Cheng-ji; Liu, Hong-zhen

    2012-05-01

    To explore the influence of different strength intermittent treadmill training of growth period rats on the bone metabolism, so as to provide the training intensity of teenagers to set theory support. Select 70 male four weeks Wistar rats according to body weight randomly divided into seven groups (n = 10): the control group and the exercise group. According to the VO2max the exercise group was divided into 6 groups: 65%, 70%, 75%, 80%, 85% and 90% group. Nine weeks treadmill training, training six days a week, each group of training three times, each time not less than 10min, the interval was 30 min. The last movement after 24 h, took the femur and blood to measured the bone mineral density (BMD), bone mass (BMC) and alkaline phosphatase (AKP), resist tartaric acid acidic phosphatase (Str-ACP). 1. The femoral BMD (0.1393 +/- 0.0031), BMC (0.4525 +/- 0.0335) of 70% group were significantly higher than those in the control group (BMD: 0.1200 +/- 0.0095, BMC: 0.3238 +/- 0.0485) and the other sports group (65% BMD:0.1339 +/- 0.0062, BMC: 0.4058 +/- 0.0492, 75% BMD: 0.1296 +/- 0.0015, BMC: 0.3869 +/- 0.0254, 80% BMD: 0.1223 +/- 0.0082, BMC: 0.3454 +/- 0.0483, 85% BMD: 0.1250 +/- 0.0044, BMC: 0.3731 +/- 0.0381, 90% BMD: 0.1171 +/- 0.0047, BMC: 0.3051 +/- 0.0286) (P growth period rat bone mass and bone mineral density to increase obviously.

  7. Culture and ethnicity influence outcomes of the Scoliosis Research Society Instrument in adolescent idiopathic scoliosis.

    Science.gov (United States)

    Morse, Lee Jae; Kawakami, Noriaki; Lenke, Lawrence G; Sucato, Daniel J; Sanders, James O; Diab, Mohammad

    2012-05-20

    Retrospective comparative study. To report preoperative differences in the Scoliosis Research Society Outcomes Instrument (SRS-30) between multiple US ethnicities and native Japanese and Korean children with adolescent idiopathic scoliosis (AIS). The SRS-24 was developed in a US cohort with AIS. Comparative studies using the SRS-24 between US and Japanese patients showed differences, suggesting that culture might affect functional outcome. Preoperative SRS-30 outcomes were collected from 1853 children with AIS from 6 different ethnic groups: US white (1234), black (213), Hispanic (78), and Asian (29), as well as native Japanese (192) and Koreans (107). Analysis of covariance of 4 SRS-30 domains (pain, appearance, activity, and mental) was compared between groups adjusting for differences in age, sex, major curve magnitude, and body mass index. Pairwise comparisons of the 4 SRS-30 domains were adjusted for multiple comparisons, using Bonferroni correction. A P value of less than 0.05 was considered significant. Significant differences between ethnicities were found in all domains (P Culture and ethnicity influence SRS-30 outcomes in AIS. Whites reported more pain than Japanese and Koreans. Japanese and Koreans had the lowest appearance scores. Koreans additionally were distinguished by the lowest activity, mental, and total scores. These cultural and ethnic differences must be taken into account when counseling patients with AIS and studying functional outcomes.

  8. Influence of body habitus on feasibility and outcome of laparoscopic liver resections: a prospective study.

    Science.gov (United States)

    Ratti, Francesca; D'Alessandro, Valentina; Cipriani, Federica; Giannone, Fabio; Catena, Marco; Aldrighetti, Luca

    2016-06-01

    The aim of the present study was to prospectively investigate whether the anthropometric measures of A Body Shape Index (ABSI, taking into account waist circumference adjusted for height and weight) affects feasibility and outcome of laparoscopic liver resections. One hundred patients undergoing laparoscopic liver resection were prospectively included in the study (2014-2015). Preoperative clinical parameters, including body mass index (BMI) and ABSI were evaluated for associations with intraoperative outcome and postoperative results (morbidity, mortality and functional recovery). Twenty-two and 78 patients underwent major and minor hepatectomies, respectively. Conversion rate was 9%, mean blood loss was 210 ± 115 ml. Postoperative morbidity was 15% and mortality was nil. Mean length of stay was 4 days. When considering the entire series, ABSI was not associated with intra and postoperative outcome. After stratification of patients according to difficulty score, Pearson's correlation demonstrated an association between ABSI and intraoperative blood loss (P = 0.03) and time for functional recovery (P = 0.05) in patients undergoing resections with high score of difficulty. Body habitus has an influence on outcome of laparoscopic liver resections with high degree of difficulty, while feasibility and outcome of low difficulty resections seem not to be affected by anthropometric measures. © 2016 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

  9. It's all in the attitude: The role of job attitude strength in job attitude-outcome relationships.

    Science.gov (United States)

    Schleicher, Deidra J; Smith, Troy A; Casper, Wendy J; Watt, John D; Greguras, Gary J

    2015-07-01

    Integrating attitude theory with the job attitudes literature, we position job attitude strength (JAS) as a missing yet important theoretical concept in the study of job attitudes. We examine JAS as a moderator of the relationship between job satisfaction and several criteria of interest to organizational scholars (job performance, organizational citizenship behavior, withdrawal). We also examine multiple relevant indicators of JAS (i.e., attitude certainty, attitude extremity, latitude of rejection, and structural consistency), both to shed light on its conceptual nature and to provide meaningful practical direction to researchers interested in incorporating JAS into job attitude research. Data were collected in five field samples (total N = 816). Results support our hypotheses: JAS moderates the relationships between job satisfaction and performance, organizational citizenship behavior, and turnover intentions; in each case, these relationships are significantly stronger for employees with stronger job satisfaction attitudes. However, as expected, not all JAS indicators are equally effective as moderators. We discuss our findings in terms of their theoretical, empirical, and practical implications for the future study of job attitudes. (c) 2015 APA, all rights reserved).

  10. Influence of arterial occlusion on outcome after intravenous thrombolysis for acute ischemic stroke.

    Science.gov (United States)

    Medlin, Friedrich; Amiguet, Michael; Vanacker, Peter; Michel, Patrik

    2015-01-01

    We aimed to assess the interaction between intravenous thrombolysis (IVT) and arterial occlusion on acute cervicocerebral computed tomographic angiography on the outcome of patients with acute ischemic stroke. Patients from the Acute Stroke Registry and Analysis of Lausanne (ASTRAL) registry with onset-to-door-time ≤4 hours, acute cervicocerebral computed tomographic angiography, a premorbid modified Rankin Scale ≤2, and a National Institute of Health Stroke Scale (NIHSS) >4 were selected. Patients with significant intracranial arterial obstruction (≥50%-99%) and undergoing acute endovascular treatment were excluded. An interaction analysis of IVT and initial arterial occlusion for favorable 3 months outcome (modified Rankin Scale <3) were performed with adjustment for potential confounders. Among 654 included patients, 382 (58%) showed arterial occlusion, of whom 263 (69%) received IVT. Two hundred seventy-two showed no/minimal obstruction of whom 139 (51%) received IVT. In the adjusted interaction analysis, there was a trend in favor of the arterial occlusion group (odds ratio [OR]=3.97; 95% confidence interval [CI], 0.83-18.97; P=0.08). IVT (versus no IVT) was associated with better outcome in patients with occlusion (adjusted OR for favorable outcome, 3.01; 95% CI, 1.10-8.28) but not in patients with no/minimal obstruction (OR, 0.76; 95% CI, 0.21-2.74). Conversely, patients with occlusion had a similar rate of favorable outcome as no/minimal obstruction when thrombolysed (OR, 0.5; 95% CI, 0.17-1.47) but had a less favorable outcome without thrombolysis (OR, 0.13; 95% CI, 0.04-0.44). In this retrospective analysis of consecutive patients with acute ischemic stroke, there was a trend for more favorable outcomes with IVT in the setting of initial arterial occlusion than in the setting of no/minimal obstruction. Before confirmation in randomized controlled studies, this information should not influence thrombolysis decisions, however. © 2014 American Heart

  11. Effects of High Intensity Interval Training and Strength Training on Metabolic, Cardiovascular and Hormonal Outcomes in Women with Polycystic Ovary Syndrome: A Pilot Study.

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    Ida Almenning

    Full Text Available Polycystic ovary syndrome is a common endocrinopathy in reproductive-age women, and associates with insulin resistance. Exercise is advocated in this disorder, but little knowledge exists on the optimal exercise regimes. We assessed the effects of high intensity interval training and strength training on metabolic, cardiovascular, and hormonal outcomes in women with polycystic ovary syndrome.Three-arm parallel randomized controlled trial. Thirty-one women with polycystic ovary syndrome (age 27.2 ± 5.5 years; body mass index 26.7 ± 6.0 kg/m2 were randomly assigned to high intensity interval training, strength training, or a control group. The exercise groups exercised three times weekly for 10 weeks.The main outcome measure was change in homeostatic assessment of insulin resistance (HOMA-IR. HOMA-IR improved significantly only after high intensity interval training, by -0.83 (95% confidence interval [CI], -1.45, -0.20, equal to 17%, with between-group difference (p = 0.014. After high intensity interval training, high-density lipoprotein cholesterol increased by 0.2 (95% CI, 0.02, 0.5 mmol/L, with between group difference (p = 0.04. Endothelial function, measured as flow-mediated dilatation of the brachial artery, increased significantly after high intensity interval training, by 2.0 (95% CI, 0.1, 4.0 %, between-group difference (p = 0.08. Fat percentage decreased significantly after both exercise regimes, without changes in body weight. After strength training, anti-Müllarian hormone was significantly reduced, by -14.8 (95% CI, -21.2, -8.4 pmol/L, between-group difference (p = 0.04. There were no significant changes in high-sensitivity C-reactive protein, adiponectin or leptin in any group.High intensity interval training for ten weeks improved insulin resistance, without weight loss, in women with polycystic ovary syndrome. Body composition improved significantly after both strength training and high intensity interval training. This pilot

  12. Effects of High Intensity Interval Training and Strength Training on Metabolic, Cardiovascular and Hormonal Outcomes in Women with Polycystic Ovary Syndrome: A Pilot Study.

    Science.gov (United States)

    Almenning, Ida; Rieber-Mohn, Astrid; Lundgren, Kari Margrethe; Shetelig Løvvik, Tone; Garnæs, Kirsti Krohn; Moholdt, Trine

    2015-01-01

    Polycystic ovary syndrome is a common endocrinopathy in reproductive-age women, and associates with insulin resistance. Exercise is advocated in this disorder, but little knowledge exists on the optimal exercise regimes. We assessed the effects of high intensity interval training and strength training on metabolic, cardiovascular, and hormonal outcomes in women with polycystic ovary syndrome. Three-arm parallel randomized controlled trial. Thirty-one women with polycystic ovary syndrome (age 27.2 ± 5.5 years; body mass index 26.7 ± 6.0 kg/m2) were randomly assigned to high intensity interval training, strength training, or a control group. The exercise groups exercised three times weekly for 10 weeks. The main outcome measure was change in homeostatic assessment of insulin resistance (HOMA-IR). HOMA-IR improved significantly only after high intensity interval training, by -0.83 (95% confidence interval [CI], -1.45, -0.20), equal to 17%, with between-group difference (p = 0.014). After high intensity interval training, high-density lipoprotein cholesterol increased by 0.2 (95% CI, 0.02, 0.5) mmol/L, with between group difference (p = 0.04). Endothelial function, measured as flow-mediated dilatation of the brachial artery, increased significantly after high intensity interval training, by 2.0 (95% CI, 0.1, 4.0) %, between-group difference (p = 0.08). Fat percentage decreased significantly after both exercise regimes, without changes in body weight. After strength training, anti-Müllarian hormone was significantly reduced, by -14.8 (95% CI, -21.2, -8.4) pmol/L, between-group difference (p = 0.04). There were no significant changes in high-sensitivity C-reactive protein, adiponectin or leptin in any group. High intensity interval training for ten weeks improved insulin resistance, without weight loss, in women with polycystic ovary syndrome. Body composition improved significantly after both strength training and high intensity interval training. This pilot study

  13. The sleeping patterns of Head Start children and the influence on developmental outcomes.

    Science.gov (United States)

    Schlieber, M; Han, J

    2018-05-01

    Sleep has a significant influence on children's development. The objective of this study was to investigate Head Start children's sleeping patterns and the impact on cognitive and behavioural outcomes. Using the 2009 cohort of the Head Start Family and Child Experiences Survey (N = 2,868), information on sleeping patterns was assessed through parent interviews. Cognitive outcomes were assessed using direct assessments (Peabody Picture Vocabulary Test-IV, the Expressive One-Word Picture Vocabulary Test, and Subtests of the Woodcock-Johnson III) in addition to teacher report. Behavioural outcomes were assessed through parent and teacher reports. A multiple regression analysis was performed for each outcome variable. Descriptive findings showed that 89% of children had a regular bedtime at least 4 days per week and that the average amount of sleep per night was 10.41 hr. White mothers were more likely than other racial groups to adhere to a consistent bedtime, and maternal employment predicted less hour of sleep per night. Multiple regression analyses revealed that disrupted sleep had a negative influence on cognitive outcomes, especially in areas of mathematical problem solving, receptive language, teacher-reported literacy behaviours, and approaches to learning. Disrupted sleep was associated with the risk of misbehaviour by increasing teacher and parent ratings on aggressive behaviours, hyperactivity, and withdrawing in addition to decreased scores on overall social skills. Having an inconsistent bedtime negatively predicted expressive vocabulary and teacher-reported literacy behaviours. The findings of this study support the influential role of sleep on children's development. Sleeping through the night and having a consistent bedtime were found to be predictive of many areas of cognitive and behavioural development. Head Start staff can provide the supports to increase parental knowledge on appropriate child sleep practices. © 2017 John Wiley & Sons Ltd.

  14. Influence of personality on the outcome of treatment in depression: systematic review and meta-analysis.

    Science.gov (United States)

    Newton-Howes, Giles; Tyrer, Peter; Johnson, Tony; Mulder, Roger; Kool, Simone; Dekker, Jack; Schoevers, Robert

    2014-08-01

    There continues to be debate about the influence of personality disorder on the outcome of depressive disorders and is relative interactions with treatment. To determine whether personality disorder, both generically and in terms of individual clusters, leads to a worse outcome in patients with depressive disorders and whether this is influenced by type of treatment, a systematic electronic search of MEDLINE, CINAHL, and PsycINFO from 1966, 1982, and 1882, respectively, until February 2007 was undertaken. The keyword terms depression, mental illness, and personality disorder were used. All references were reviewed and personal correspondence was undertaken. Only English language papers were considered. Any English language paper studying a depressed adult population was considered for inclusion. Studies needed to clearly define depression and personality disorder using peer-reviewed instruments or International Classification of Disease/Diagnostic Statistical Manual criteria. Outcome assessment at greater than 3 weeks was necessary. Final inclusion papers were agreed on by consensus by at least two reviewers. All data were extracted using predetermined criteria for depression by at least two reviewers in parallel. Disagreement was settled by consensus. Complex data extraction was confirmed within the study group. Data were synthesized using log odds ratios in the Cochrane RevMan 5 program. The finding of comorbid personality disorder and depression was associated with a more than double the odds of a poor outcome for depression compared with those with no personality disorder (OR 2.16, CI 1.83-2.56). This effect was not ameliorated by the treatment modality used for the depressive disorder. This finding led to the conclusion that personality disorder has a negative impact on the outcome of depression. This finding is important in considering prognosis in depressive disorders.

  15. HORMONE REPLACEMENT AND STRENGTH TRAINING POSITIVELY INFLUENCE BALANCE DURING GAIT IN POST-MENOPAUSAL FEMALES: A PILOT STUDY

    Directory of Open Access Journals (Sweden)

    Stephen D. Perry

    2005-12-01

    Full Text Available This study examined the effects of hormone replacement combined with strength training on improving dynamic balance control in post-menopausal women. Thirty one participating post-menopausal women were divided into three groups (hormone replacement (HR, non-hormone replacement (NR and control (CR group. HR and NR groups were tested for muscle strength and balance control during gait, prior to training and following a six week lower body strength training program. Quadriceps muscle strength was evaluated as isokinetic peak torque (60°·sec-1 using a CYBEX NORM and balance control was evaluated by center of mass - base of support relationships and ground reaction forces during gait perturbations. Only the HR group showed significantly (p < 0.05 improved balance control during the initial phase of unexpected gait termination and single stance periods while walking across uneven terrain following training. The strength gains in the HR group tended to be greater than in the NR group over the six week training program, although neither group showed statistically significant increases. The CR group showed no significant differences between testing times. HR in post-menopausal females may enhance dynamic balance control when combined with a strength training program, even if no statistically significant gains in strength are achieved

  16. Comorbidity negatively influences the outcomes of diagnostic tests for musculoskeletal pain in the orofacial region.

    Science.gov (United States)

    Koutris, Michail; Visscher, Corine M; Lobbezoo, Frank; Naeije, Machiel

    2013-06-01

    The aim of this study was to investigate whether diagnostic tests for musculoskeletal pain in the orofacial region [temporomandibular disorder (TMD) pain] are influenced by the presence of comorbid conditions, and to determine whether this influence decreases when the presence of "familiar pain" is used as outcome measure. In total, 117 patients (35 men, 82 women; 75 TMD-pain patients, 42 pain-free patients; mean age ± SD = 42.94 ± 14.17 years) were examined with palpation tests and dynamic/static tests. After each test, they were asked whether any pain was provoked and whether this pain response was familiar or not. For four clinical outcome measures (pain on palpation, familiar pain on palpation, pain on dynamic/static tests, and familiar pain on dynamic/static tests), multiple logistic regression analyses were performed with the presence of TMD pain as the primary predictor and regional (neck/shoulder) pain, widespread pain, depression, and somatization as comorbid factors. Pain on palpation was not associated with the primary predictor but with regional pain [P = 0.02, odds ratio (OR) = 4.59] and somatization (P = 0.011, OR = 8.47), whereas familiar pain on palpation was associated with the primary predictor (P = 0.003, OR = 5.23), but also with widespread pain (P = 0.001, OR = 2.02). Pain on dynamic/static tests was associated with the primary predictor (P pain on dynamic/static tests was only associated with the primary predictor (P diagnostic tests are negatively influenced by the presence of comorbidity. This influence decreases when the presence of familiar pain is used as outcome measure. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  17. The relative influence of maternal nutritional status before and during pregnancy on birth outcomes in Vietnam.

    Science.gov (United States)

    Young, Melissa F; Nguyen, Phuong Hong; Addo, O Yaw; Hao, Wei; Nguyen, Hieu; Pham, Hoa; Martorell, Reynaldo; Ramakrishnan, Usha

    2015-11-01

    This study aimed to: (1) examine the role of multiple measures of prepregnancy nutritional status (weight, height, body composition) on birth outcomes (low birth weight (LBW), small for gestational age (SGA), preterm, birth weight, birth length, infant head circumference and mid-upper arm circumference (MUAC)); (2) assess relative influence of maternal nutritional status before and during (gestational weight gain) pregnancy on birth outcomes. We used prospective data on maternal body size and composition collected from women who participated in a randomized controlled trial evaluating the impact of preconceptional micronutrient supplements (PRECONCEPT) on birth outcomes in Thai Nguyen province, Vietnam (n=1436). Anthropometric measurements were obtained before conception through delivery by trained health workers. The relationship between prepregnancy nutritional status indicators, gestational weight gain (GWG) and birth outcomes were examined using generalized linear models, adjusting for potential confounding factors. Maternal prepregnancy weight (PPW) was the strongest anthropometric indicator predicting infant birth size. A 1 standard deviation (SD) increase in PPW (5.4kg) was associated with a 283g (95%CI: 279-286) increase in birthweight. A similar and independent association was observed with birthweight for an increase of 1 SD in gestational weight gain (4kg) (250g; 95% CI: 245-255). Women with a PPW pregnancy were more likely to give birth to a SGA (OR 2.9: 95%CI 1.9-4.5, OR 3.3: 95%CI 2.2-5.1) or LBW infant (OR 3.1: 95%CI 1.5-6.2, OR 3.4: 95%CI 1.6-7.2), respectively. These findings indicate that clinical care and programs aimed at improving birth outcomes will have the greatest impact if they address maternal nutrition both before and during pregnancy. Women with a PPW pregnancy along with routine obstetric care on gestational weight gain is critical to improve birth outcomes. NCT01665378 (https://clinicaltrials.gov/show/NCT01665378). Copyright © 2015

  18. Effects of gastrocnemius recession on ankle motion, strength, and functional outcomes: a systematic review and national healthcare database analysis.

    Science.gov (United States)

    Gianakos, Arianna; Yasui, Youichi; Murawski, Christopher D; Kennedy, John G

    2016-04-01

    The purpose of this systematic review was to report the effects of gastrocnemius recession on ankle dorsiflexion range of motion, function, and push-off power. The MEDLINE and EMBASE databases were reviewed with terms "gastrocnemius recession". The inclusion criteria were: (1) clinical studies, (2) published in a peer-reviewed journal within the past 10 years, and (3) published in English. Excluded were: (1) review articles, (2) cadaveric studies, (3) studies including patients under the age of 18 years, (4) studies evaluating a neurologic condition, (5) level of evidence 5, and (6) Quality of Evidence Score fashion with variable results, but of these, no study reported a return to normal power. The mean complication rate was 14%. The available evidence supports that GR improves functional outcomes and increases dorsiflexion range of motion. Furthermore, GR affects gait kinematics, which may cause compensatory effects at the knee, ankle, and subtalar joints. Evidence has shown that power does not return to normal levels. Clinicians may utilize these data clinically to determine whether patients may benefit from GR or not. IV.

  19. Influence of steel fibers on the shear and flexural performance of high-strength concrete beams tested under blast loads

    Science.gov (United States)

    Algassem, O.; Li, Y.; Aoude, H.

    2017-09-01

    This paper presents the results of a study examining the effect of steel fibres on the blast behaviour of high-strength concrete beams. As part of the study, a series of three large-scale beams built with high-strength concrete and steel fibres are tested under simulated blast loading using the shock-tube testing facility at the University of Ottawa. The specimens include two beams built with conventional high-strength concrete (HSC) and one beam built with high-strength concrete and steel fibres (HSFRC). The effect of steel fibres on the blast behaviour is examined by comparing the failure mode, mid-span displacements and, overall blast resistance of the specimens. The results show that the addition of steel fibres in high-strength concrete beams can prevent shear failure and substitute for shear reinforcement if added in sufficient quantity. Moreover, the use of steel fibres improves flexural response under blast loading by reducing displacements and increasing blast capacity. Finally, the provision of steel fibres is found to improve the fragmentation resistance of high-strength concrete under blast loads.

  20. Optimism Moderates the Influence of Pain Catastrophizing on Shoulder Pain Outcome: A Longitudinal Analysis.

    Science.gov (United States)

    Coronado, Rogelio A; Simon, Corey B; Lentz, Trevor A; Gay, Charles W; Mackie, Lauren N; George, Steven Z

    2017-01-01

    Study Design Secondary analysis of prospectively collected data. Background An abundance of evidence has highlighted the influence of pain catastrophizing and fear avoidance on clinical outcomes. Less is known about the interaction of positive psychological resources with these pain-associated distress factors. Objective To assess whether optimism moderates the influence of pain catastrophizing and fear avoidance on 3-month clinical outcomes in patients with shoulder pain. Methods Data from 63 individuals with shoulder pain (mean ± SD age, 38.8 ± 14.9 years; 30 female) were examined. Demographic, psychological, and clinical characteristics were obtained at baseline. Validated measures were used to assess optimism (Life Orientation Test-Revised), pain catastrophizing (Pain Catastrophizing Scale), fear avoidance (Fear-Avoidance Beliefs Questionnaire physical activity subscale), shoulder pain intensity (Brief Pain Inventory), and shoulder function (Pennsylvania Shoulder Score function subscale). Shoulder pain and function were reassessed at 3 months. Regression models assessed the influence of (1) pain catastrophizing and optimism and (2) fear avoidance and optimism. The final multivariable models controlled for factors of age, sex, education, and baseline scores, and included 3-month pain intensity and function as separate dependent variables. Results Shoulder pain (mean difference, -1.6; 95% confidence interval [CI]: -2.1, -1.2) and function (mean difference, 2.4; 95% CI: 0.3, 4.4) improved over 3 months. In multivariable analyses, there was an interaction between pain catastrophizing and optimism (β = 0.19; 95% CI: 0.02, 0.35) for predicting 3-month shoulder function (F = 16.8, R 2 = 0.69, Poptimism lessened the influence of pain catastrophizing on function. There was no evidence of significant moderation of fear-avoidance beliefs for 3-month shoulder pain (P = .090) or function (P = .092). Conclusion Optimism decreased the negative influence of pain

  1. Influences of Training on Individual Outcomes for High School Sports Officials

    Directory of Open Access Journals (Sweden)

    Timothy D. Ryan

    2014-04-01

    Full Text Available The primary purpose of this study was to explore the influences of training on specific quality of work outcomes of job satisfaction, pay satisfaction, and intentions to leave within high school sports officials. Evidence suggests that there is a shortage of high school officials in all categories of high school sport. Via a web-based survey, we explored the effects of training on the individual outcomes under study. Results indicated that the level of training had a significant effect on job satisfaction, pay satisfaction, and turnover intentions. Analyses indicated that officials with less training had higher turnover intentions and lower job satisfaction than officials who had more training. Conversely, officials who engaged numerous training hours had lower pay satisfaction. This exploratory study supports the importance of training high school officials but, more importantly, provides an initial assessment on the reverse effects of training on pay satisfaction.

  2. The Influence Of Learning Model Guided Findings Of Student Learning Outcomes

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    A. SaefulBahri

    2015-03-01

    Full Text Available Abstract This study examines the influence of the learning model guided findings on student learning outcomes in subjects PAI eighth grade students of SMP Plus al Masoem. The research method used in this study is a quantitative method in the form of quasi-experiment Quasi-Experimental Design. The findings of the study are expected to demonstrate 1 the difference significant increase in learning outcomes between the experimental class using guided discovery method that uses the control class discussion of learning models 2 Constraints in the method of guided discovery activities and the limited ability of educators in the experimental class in implements the method of guided discovery and constraints faced by students while digging the information they need so we need special strategies to motivate students in the experimental class in order for them creatively find the right way to gather information that supports learning PAI.

  3. Influence of sand to coarse aggregate ratio on the interfacial bond strength of steel fibers in concrete for nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Jin, E-mail: jjinslow@nate.com [Department of Civil and Environmental Engineering, SeJong University, 98 Gunja-Dong, Gwangjin-Gu, Seoul 143-747 (Korea, Republic of); Kim, Dong Joo, E-mail: djkim75@sejong.ac.kr [Department of Civil and Environmental Engineering, SeJong University, 98 Gunja-Dong, Gwangjin-Gu, Seoul 143-747 (Korea, Republic of); Kang, Su Tae, E-mail: stkang@daegu.ac.kr [Department of Civil Engineering, Daegu University, 201 Daegudae-ro, Jillyang, Gyeongsan, Gyeongbuk 712-714 (Korea, Republic of); Lee, Jang Hwa, E-mail: jhlee@kict.re.kr [Korea Institute of Construction Technology, 2311 Daewha-Dong, Ilsan-Gu, Goyang-Si, Gyeonggi-Do 411-712 (Korea, Republic of)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The final goal is to develop a fiber reinforced concrete for containment buildings. Black-Right-Pointing-Pointer We investigated the effect of S/a on the bond strength of steel fibers. Black-Right-Pointing-Pointer Deformed steel fibers produced much higher interfacial bond strength. Black-Right-Pointing-Pointer As S/a increased, twisted fiber showed a significant enhancement in bond strength. Black-Right-Pointing-Pointer Smooth and hooked fiber showed no clear difference as S/a increased. - Abstract: The interfacial bond strength of three high strength steel fibers (smooth, hooked, and twisted fiber) in concrete of nuclear power plants was investigated to develop fiber reinforced concrete for containment building. Sand to aggregate ratio (S/a) was adjusted to compensate reduction in the workability due to adding fibers; the influence of S/a ratio on the interfacial bond strength was investigated. As the S/a ratio increased from 0.444 to 0.615, the bond strength of twisted steel fiber was significantly improved while smooth and hooked steel fiber showed no clear difference. The different sensitivity according to the S/a ratio results from the different pullout mechanism: twisted steel fiber generates more mechanical interaction during fiber pullout at the interface between fiber and matrix than smooth and hooked fibers. The microscopic observation by scanning electron microscope back-scattered electrons images discovered lower porosity at the interfacial transition zone between fiber and concrete with higher S/a ratio.

  4. The Influence of GI and GII on the Compression After Impact Strength of Carbon Fiber/Epoxy Laminates and Sandwich Structure

    Science.gov (United States)

    Nettles, A. T.; Scharber, L. L.

    2017-01-01

    This study measured the compression after impact strength of IM7 carbon fiber laminates made from epoxy resins with various mode I and mode II toughness values to observe the effects of these toughness values on the resistance to damage formation and subsequent residual compression strength-carrying capabilities. Both monolithic laminates and sandwich structure were evaluated. A total of seven different epoxy resin systems were used ranging in approximate GI values of 245-665 J/sq m and approximate GII values of 840-2275 J/sq m. The results for resistance to impact damage formation showed that there was a direct correlation between GII and the planar size of damage, as measured by thermography. Subsequent residual compression strength testing suggested that GI had no influence on the measured values and most of the difference in compression strength was directly related to the size of damage. Thus, delamination growth assumed as an opening type of failure mechanism does not appear to be responsible for loss of compression strength in the specimens examined in this study.

  5. A comparative study to determine strength of autopolymerizing acrylic resin and autopolymerizing composite resin influenced by temperature during polymerization: An In Vitro study

    Directory of Open Access Journals (Sweden)

    Anuj Chhabra

    2017-01-01

    Full Text Available Aim: Temporary coverage of a prepared tooth is an important step during various stages of the fixed dental prosthesis. Provisional restorations should satisfy proper mechanical requirements to resist functional and nonfunctional loads. A few studies are carried out regarding the comparison of the effect of curing environment, air and water, on mechanical properties of autopolymerizing acrylic and composite resin. Hence, the aim of this study was to compare the transverse strength of autopolymerizing acrylic resin and autopolymerizing composite resin as influenced by the temperature of air and water during polymerization. Materials and Methods: Samples of autopolymerizing acrylic resin and composite resin were prepared by mixing as per manufacturer's instructions and were placed in a preformed stainless steel mold. The mold containing the material was placed under different controlled conditions of water temperature and air at room temperature. Polymerized samples were then tested for transverse strength using an Instron universal testing machine. Results: Alteration of curing condition during polymerization revealed a significant effect on the transverse strength. The transverse strength of acrylic resin specimens cured at 60°C and composite resin specimens cured at 80°C was highest. Polymerizing the resin in cold water at 10°C reduced the mechanical strength. Conclusions: Polymerization of the resin in hot water greatly increased its mechanical properties. The method of placing resin restoration in hot water during polymerization may be useful for improving the mechanical requirements and obtaining long-lasting performance.

  6. Influence of intrauterine and extrauterine growth on neurodevelopmental outcome of monozygotic twins

    Directory of Open Access Journals (Sweden)

    R.K. Reolon

    2008-08-01

    Full Text Available There have been indications that intrauterine and early extrauterine growth can influence childhood mental and motor function. The objective of the present study was to evaluate the influence of intrauterine growth restriction and early extrauterine head growth on the neurodevelopmental outcome of monozygotic twins. Thirty-six monozygous twin pairs were evaluated at the corrected age of 12 to 42 months. Intrauterine growth restriction was quantified using the fetal growth ratio. The effects of birth weight ratio, head circumference at birth and current head circumference on mental and motor outcomes were estimated using mixed-effect linear regression models. Separate estimates of the between (interpair and within (intrapair effects of each measure on development were thus obtained. Neurodevelopment was assessed with the Bayley Scales of Infant Development, 2nd edition, by a psychologist blind to the exposure. A standardized neurological examination was performed by a neuropediatrician who was unaware of the exposures under investigation. After adjustment, birth weight ratio and head circumference at birth were not associated with motor or mental outcomes. Current head circumference was associated with mental but not with motor outcomes. Only the intrapair twin effect was significant. An increase of 1 cm in current head circumference of one twin compared with the other was associated with 3.2 points higher in Mental Developmental Index (95%CI = 1.06-5.32; P < 0.03. Thus, no effect of intrauterine growth was found on cognition and only postnatal head growth was associated with cognition. This effect was not shared by the co-twin.

  7. Influence of corneal asphericity on the refractive outcome of intraocular lens implantation in cataract surgery.

    Science.gov (United States)

    Savini, Giacomo; Hoffer, Kenneth J; Barboni, Piero

    2015-04-01

    To evaluate the possible influence of anterior corneal surface asphericity on the refractive outcomes in eyes having intraocular lens (IOL) implantation after cataract surgery. Fondazione G.B. Bietti IRCCS, Rome, Italy. Retrospective comparative case series. Intraocular lens power was calculated using the Haigis, Hoffer Q, Holladay 1, and SRK/T formulas. Asphericity (Q-value) was measured at 8.0 mm with a Placido-disk corneal topographer (Keratron), a rotating Scheimpflug camera (Pentacam), and a rotating Scheimpflug camera combined with Placido-disk corneal topography (Sirius). The relationship between the error in refraction prediction (ie, difference between expected refraction and refraction measured 1 month after surgery) and the Q-value was assessed by linear regression. The same IOL model (Acrysof SA60AT) was implanted in 115 eyes of 115 consecutive patients. Regression analysis showed a statistically significant relationship between the error in refraction prediction and the Q-value with all formulas and all devices. In all cases, a more negative Q-value (prolate cornea) was associated with a myopic outcome, whereas a more positive Q-value (oblate cornea) was associated with a hyperopic outcome. The highest coefficient of determination was detected between the Hoffer Q formula and the Placido-disk corneal topographer (R(2) = 0.2630), for which the error in refraction prediction (y) was related to the Q-value (x) according to the formula y = -0.2641 + 1.4589 × x. Corneal asphericity influences the refractive outcomes of IOL implantation and should be taken into consideration when using third-generation IOL power formulas. Dr. Hoffer receives book royalties from Slack, Inc., Thorofare, New Jersey, and formula royalties from all manufacturers using the Hoffer Q formula. No other author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  8. The Influence of Methotrexate Treatment on Male Fertility and Pregnancy Outcome After Paternal Exposure.

    Science.gov (United States)

    Grosen, Anne; Kelsen, Jens; Hvas, Christian Lodberg; Bellaguarda, Emanuelle; Hanauer, Stephen B

    2017-04-01

    Inflammatory bowel disease incidence peaks during the reproductive years. Methotrexate (MTX) is frequently used for inflammatory bowel disease, but its use during pregnancy is contraindicated in women because of teratogenic effects. The aim of this review is to investigate the influence of MTX on male fertility and pregnancy outcomes after paternal MTX exposure. A systematic literature search was performed by applying 2 focus areas, "methotrexate" and "male fertility or pregnancy outcome." Terms and keywords were used both as MeSH terms and free-text searches. Pertinent articles were searched for additional relevant references. In animal studies, MTX induces aberrations in sperm DNA that have not been identified in humans. The effects of MTX on human sperm quality have only been described in case reports. A transient adverse effect on sperm quality with low-dose MTX has been reported, but several other cases have not found harmful effects of MTX. MTX has not been measured in human sperm ejaculates; yet, the risk of a direct toxic effect on the fetus through MTX-contaminated seminal plasma seems negligible. Until now, 284 pregnancies with paternal MTX exposure have been reported. The outcomes were 248 live births and a total of 13 malformations, with no overt indication of MTX embryopathy. This review reveals the lack of studies on the safety of MTX with regard to male reproduction. It is not clear whether MTX transiently influences male fertility and sperm DNA integrity, and more studies are needed. Comparative cohort studies found no increased risk of adverse pregnancy outcomes.

  9. Academic season does not influence cardiac surgical outcomes at US Academic Medical Centers.

    Science.gov (United States)

    Lapar, Damien J; Bhamidipati, Castigliano M; Mery, Carlos M; Stukenborg, George J; Lau, Christine L; Kron, Irving L; Ailawadi, Gorav

    2011-06-01

    Previous studies have demonstrated the influence of academic season on outcomes in select surgical populations. However, the influence of academic season has not been evaluated nationwide in cardiac surgery. We hypothesized that cardiac surgical outcomes were not significantly influenced by time of year at both cardiothoracic teaching hospitals and non-cardiothoracic teaching hospitals nationwide. From 2003 to 2007, a weighted 1,614,394 cardiac operations were evaluated using the Nationwide Inpatient Sample database. Patients undergoing cardiac operations at cardiothoracic teaching and non-cardiothoracic teaching hospitals were identified using the Association of American Medical College's Graduate Medical Education Tracking System. Hierarchic multivariable logistic regression analyses were used to estimate the effect of academic quarter on risk-adjusted outcomes. Mean patient age was 65.9 ± 10.9 years. Women accounted for 32.8% of patients. Isolated coronary artery bypass grafting was the most common operation performed (64.7%), followed by isolated valve replacement (19.3%). The overall incidence of operative mortality and composite postoperative complication rate were 2.9% and 27.9%, respectively. After accounting for potentially confounding risk factors, timing of operation by academic quarter did not independently increase risk-adjusted mortality (p = 0.12) or morbidity (p = 0.24) at academic medical centers. Risk-adjusted mortality and morbidity for cardiac operations were not associated with time of year in the US at teaching and nonteaching hospitals. Patients should be reassured of the safety of performance of cardiac operations at academic medical centers throughout a given academic year. Copyright © 2011 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  10. Influence of superplasticizer on microstructure of a 40 MPa strength concrete; Influencia do aditivo superplastificante na microestrutura de um concreto de resistencia mecanica de 40 MPa

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Sandra M.F.; Menezes, Raquel Maria R.O.; Figueiredo, Roberto B.; Aguilar, Maria Teresa P. [Universidade Federal de Minas Gerais (UFMG), MG (Brazil); Franca, Fabricio Carlos [LafargeHolcim, Rio de Janeiro, RJ (Brazil); Bezerra, Augusto Cesar da S. [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET-MG), MG (Brazil)

    2016-07-01

    The self compacting concrete has high fluidity and deformability. Studies analyze its performance through compressive strength, mortar content and / or water cement factor, which does not allow the evaluation of superplasticante influence the microstructure of these concretes. In this work, we evaluated the influence of superplasticizer comparing the phases present in a self-compacting concrete 40 MPa and at a same conventional compressive strength, same water / cement and mortar content. Therefore, scanning techniques were employed by electron microscope low vacuum using backscattered electrons and thermal analysis. The observed results show no significant differences in the microstructure of the two composites, ie the superplasticizer does not alter the microstructure of the self-compacting concrete. However, thermal analysis indicates that the present self-compacting concrete greater calcium hydroxide content which may suggest a lower content of such dry cement concrete. (author)

  11. Influence of diabetes and hyperglycaemia on infectious disease hospitalisation and outcome

    DEFF Research Database (Denmark)

    Benfield, Thomas; Jensen, J S; Nordestgaard, B G

    2007-01-01

    AIMS/HYPOTHESIS: Diabetes mellitus is believed to increase susceptibility to infectious diseases. The effects of hyperglycaemia per se on infectious disease risk are unknown and the influence of diabetes on infectious disease outcome is controversial. MATERIALS AND METHODS: We studied 10......,063 individuals from the Danish general population, who were participants in The Copenhagen City Heart Study, over a follow-up period of 7 years. Risk of hospitalisation caused by any infectious disease, and subsequent risk of disease progression to death were estimated by Cox proportional hazards regression...

  12. Comorbid Diagnosis of Psychotic Disorders in Borderline Personality Disorder: Prevalence and Influence on Outcome

    Directory of Open Access Journals (Sweden)

    C. W. Slotema

    2018-03-01

    Full Text Available BackgroundA diagnosis of psychotic disorder is traditionally considered incompatible with borderline personality disorder (BPD, even though patients sometimes fulfill the diagnostic criteria for both disorders. How often this happens is barely known, as is the influence of comorbid psychotic disorders on the outcome of BPD. Since studies on isolated auditory verbal hallucinations in patients with BPD indicate that these perceptual symptoms have severe consequences and are associated with suicidal behavior and hospitalization, patients with comorbid psychotic disorders are unlikely to fare better.ObjectiveTo examine the point prevalence of psychotic disorders in patients with BPD, their association with the outcome of BPD, and their predictive value for outcome.MethodsIn a cross-sectional design, 84 female outpatients diagnosed with BPD were interviewed with the aid of the MINI-International Neuropsychiatric Interview to establish the point prevalence of comorbid psychotic and other comorbid disorders. After termination of their treatment at a specialized outpatient clinic, the type of referral was considered to be a “good” outcome when they were referred to their general practitioner or to basic psychiatric care for noncomplex patients, and a “poor” outcome when referred to a specialized psychiatric department or to a psychiatric district team for patients with severe psychiatric disorders.ResultsPsychotic disorders were present in 38% of the patients with BPD. With a prevalence of 20%, psychotic disorder not otherwise specified (NOS was the most common subtype; the least common types were schizophrenia (2%, substance-induced psychotic disorder (2%, and brief psychotic disorder (1%. Among six types of comorbid disorders, only psychotic disorders were associated with a poor outcome; they were also predictors for a poor outcome, along with comorbid mood disorders, eating disorders, and somatoform disorders, as well as the severity of BPD

  13. [On the influence of D-penicillamine on collage metabolism - investigations of the rupture of strength in tailfibre in rats of several ages (author's transl)].

    Science.gov (United States)

    Trzenschik, K; Lindenhayn, K; Mühlbach, R; Napieralski, P; Noack, K

    1980-01-01

    The tensile strength of rat tail tendons of animals wtih a different age is more influenced by D-Penicillamine (DPA) in younger rats than in elderly rats. DPA has the best effect in the regions with the highest collagen turnover. After the use of DPA the collagen of tails of the elderly rats resembles the collagen of the younger animals. The reason of this alteration is probably a lower degree of cross-links of the collagen after the use of DPA.

  14. Participatory ergonomics simulation of hospital work systems: The influence of simulation media on simulation outcome

    DEFF Research Database (Denmark)

    Andersen, Simone Nyholm; Broberg, Ole

    2015-01-01

    of tool operation support ergonomics identification and evaluation related to the work system entities space and technologies & tools. The table-top models’ high fidelity of function relations and affordance of a helicopter view support ergonomics identification and evaluation related to the entity......Current application of work system simulation in participatory ergonomics (PE) design includes a variety of different simulation media. However, the actual influence of the media attributes on the simulation outcome has received less attention. This study investigates two simulation media: full......-scale mock-ups and table-top models. The aim is to compare, how the media attributes of fidelity and affordance influence the ergonomics identification and evaluation in PE design of hospital work systems. The results illustrate, how the full-scale mock-ups’ high fidelity of room layout and affordance...

  15. Influence of Anterior Cruciate Ligament Tear on Thigh Muscle Strength and Hamstring-to-Quadriceps Ratio: A Meta-Analysis

    Science.gov (United States)

    Ahn, Sung-Eun; Park, Min-Ji; Lee, Dae-Hee

    2016-01-01

    Theoretical compensation after anterior cruciate ligament (ACL) tear could cause quadriceps weakness and hamstring activation, preventing anterior tibial subluxation and affecting the expected hamstring-to-quadriceps ratio. Although quadriceps weakness often occurs after ACL tears, it remains unclear whether hamstring strength and hamstring-to-quadriceps ratio increase in ACL deficient knees. This meta-analysis compared the isokinetic muscle strength of quadriceps and hamstring muscles, and the hamstring-to-quadriceps ratio, of the injured and injured limbs of patients with ACL tears. This meta-analysis included all studies comparing isokinetic thigh muscle strengths and hamstring-to-quadriceps ratio in the injured and uninjured legs of patients with ACL tear, without or before surgery. Thirteen studies were included in the meta-analysis. Quadriceps and hamstring strengths were 22.3 N∙m (95% CI: 15.2 to 29.3 N∙m; Phamstring-to-quadriceps ratio was 4% greater in ACL deficient than in uninjured limbs (95% CI: 1.7% to 6.3%; Phamstring muscles of patients with ACL tear, with the decrease in quadriceps strength being 3-fold greater. These uneven reductions slightly increase the hamstring-to-quadriceps ratio in ACL deficient knees. PMID:26745808

  16. Influence of manganese, carbon and nitrogen on high-temperature strength of Fe-Cr-Mn austenitic alloys

    International Nuclear Information System (INIS)

    Hosoi, Y.; Okazaki, Y.; Wade, N.; Miyahara, K.

    1990-01-01

    High Mn-Cr-Fe base alloys are candidates for the first wall material of fusion reactors because of rapid decay of radioactivity of the alloys after neutron irradiation compared with that of Ni-Cr-Fe base alloys. Their high temperature properties, however, are not clearly understood at present. In this paper, a study has been made of the effects of Mn, C and N content on the high-temperature tensile strength and creep properties of a 12% CR-Fe base alloy. Mn tends to decrease tensile strength and proof stress at intermediate temperatures. At higher temperatures in the austenite range, however, tensile properties scarcely depend on Mn content. C and N additions improve the tensile properties markedly. The combined addition of 0.2%C and 0.2%N to a 12%Cr-15%Mn-Fe base alloy makes the strength at 873K as high as that of a modified type 316 stainless steel. Combined alloying with C and N also improves the creep strength. Cold working is very useful in increasing the creep strength because of the finely dispersed precipitates in the matrix during creep. From these results, Fe-12%Cr-15%Mn-15%Mn-0.2%c-0.2%N is recommended as one of the most suitable alloys in this system for high temperature usage. (author)

  17. The Influence of Trainee Gaming Experience and Computer Self-Efficacy on Learner Outcomes of Videogame-Based Learning Environments

    National Research Council Canada - National Science Library

    Orvis, Karin A; Orvis, Kara L; Belanich, James; Mullin, Laura N

    2005-01-01

    .... The purpose of the current research was to investigate the influence of two trainee characteristics, prior videogame experience and computer self-efficacy, on learner outcomes of a videogame-based training environment...

  18. Influence of median surgeon operative duration on adverse outcomes in bariatric surgery.

    Science.gov (United States)

    Reames, Bradley N; Bacal, Daniel; Krell, Robert W; Birkmeyer, John D; Birkmeyer, Nancy J O; Finks, Jonathan F

    2015-01-01

    Evidence suggests that prolonged operative time adversely affects surgical outcomes. However, whether faster surgeons have better outcomes is unclear, as a surgeon׳s speed could reflect skill and efficiency, but may alternatively reflect haste. This study evaluates whether median surgeon operative time is associated with adverse surgical outcomes after laparoscopic Roux-en-Y gastric bypass. We performed a retrospective cohort study using statewide clinical registry data from the years 2006 to 2012. Surgeons were ranked by their median operative time and grouped into terciles. Multivariable logistic regression with robust standard errors was used to evaluate the influence of median surgeon operative time on 30-day surgical outcomes, adjusting for patient and surgeon characteristics, trainee involvement, concurrent procedures, and the complex interaction between these variables. A total of 16,344 patients underwent surgery during the study period. Compared to surgeons in the fastest tercile, slow surgeons required 53 additional minutes to complete a gastric bypass procedure (median [interquartile range] 139 [133-150] versus 86 [69-91], Ppatient characteristic only, slow surgeons had significantly higher adjusted rates of any complication, prolonged length of stay, emergency department visits or readmissions, and venous thromboembolism (VTE). After further adjustment for surgeon characteristics, resident involvement, and the interaction between these variables, slow surgeons had higher rates of any complication (10.5% versus 7.1%, P=.039), prolonged length of stay (14.0% versus 4.4%, P=.002), and VTE (0.39% versus .22%, P<.001). Median surgeon operative duration is independently associated with adjusted rates of certain adverse outcomes after laparoscopic Roux-en-Y gastric bypass. Improving surgeon efficiency while operating may reduce operative time and improve the safety of bariatric surgery. Copyright © 2015 American Society for Bariatric Surgery. Published by

  19. The Influence of Consumers€™ Tie Strength, Homophily and Source Credibility Toward Electronic Word-of-mouth (Ewom) Behavior

    OpenAIRE

    Oroh, Winda Lely

    2014-01-01

    Electronic word-of-mouth (eWOM) in the form of online product reviews can influence the sales of a product and/or service, and that informational€based determinants are very important to consumers when evaluating reviews. The purpose of this research is to analyze the influence of consumers€™ tie strength, homophily, and source credibility toward electronic word-of-mouth behavior (eWOM). This research used quantitative analyze. The method used to analyze the data is the Multiple Regression A...

  20. Influence of perfusion and ventilation scans on therapeutic decision making and outcome in cases of possible embolism

    International Nuclear Information System (INIS)

    Mercandetti, A.J.; Kipper, M.S.; Moser, K.M.

    1985-01-01

    The authors examined the influence of perfusion (Q) and ventilation (V) scans on therapeutic decision making and outcome among 229 patients referred for lung scans because embolism was suggested and found that specific V/Q scan patterns strongly influenced postscan decisions regarding initiation, maintenance or cessation of heparin therapy. These therapeutic decisions bore a relationship to outcome (recurrences and death) and disclosed decision-making deficits that need remedy by future investigational and educational efforts. 25 references, 5 tables

  1. Influence of incorporation of ZrO2 nanoparticles on the repair strength of polymethyl methacrylate denture bases

    Directory of Open Access Journals (Sweden)

    Gad MM

    2016-10-01

    Full Text Available Mohammed M Gad,1 Ahmed Rahoma,2,3 Ahmad M Al-Thobity,1 Aws S ArRejaie4 1Department of Substitutive Dental Sciences, 2Department of Restorative Dental Sciences, College of Dentistry, University of Dammam, Dammam, Saudi Arabia; 3Department of Dental Materials, College of Dentistry, Al-Azhar University, Assiut, Egypt; 4Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia Background: Repeated fracture of the denture base is a common problem in prosthodontics, and it represents a nuisance and a time sink for the clinician. Therefore, the possibility of increasing repair strength using new reinforcement materials is of great interest to prosthodontists.Aim of the study: This study aimed to evaluate the effects of incorporation of zirconia nanoparticles (nano-ZrO2 on the flexural strength and impact strength of repaired polymethyl methacrylate (PMMA denture bases.Materials and methods: One hundred eighty specimens of heat-polymerized acrylic resin were fabricated (90 for each test and divided into three main groups: one control group (intact specimens and two groups divided according to surface design (45° bevels and butt joints, in which specimens were prepared in pairs to create 2.5 mm gaps. Nano-ZrO2 was added to repair resin in 2.5 wt%, 5 wt%, and 7.5 wt% concentrations of acrylic powder. A three-point bending test was used to measure flexural strength, and a Charpy-type test was used to measure impact strength. Scanning electron microscopy was used to analyze the fracture surfaces and nano-ZrO2 distribution. The results were analyzed with a paired sample t-test and an unpaired t-test, with a P-value of ≤0.05 being significant.Results: Incorporation of nano-ZrO2 into the repair resin significantly increased flexural strength (P<0.05. The highest value was found in the bevel group reinforced with 7.5% nano-ZrO2, whereas the lowest value was found in the butt group reinforced with 2.5% nano

  2. Influence of magnetic arc oscillation and current pulsing on microstructure and high temperature tensile strength of alloy 718 TIG weldments

    International Nuclear Information System (INIS)

    Sivaprasad, K.; Ganesh Sundara Raman, S.; Mastanaiah, P.; Madhusudhan Reddy, G.

    2006-01-01

    The aim of the present work is to study the effect of magnetic arc oscillation and current pulsing on the microstructure and high temperature tensile strength of alloy 718 tungsten inert gas weldments. The magnetic arc oscillation technique resulted in refined Laves phase with lesser interconnectivity. The full benefits of current pulsing in breaking the dendrites could not be realized in the present study due to relatively higher heat input used in the welding process. In the direct aged condition weldments prepared using magnetic arc oscillation technique exhibited higher tensile strength due to the presence of refined and lesser-interconnected Laves particles. In the solution treated and aged condition, magnetic arc oscillated weldments exhibited lower tensile strength compared with the weldments made without arc oscillation due to the presence of large amounts of finer δ needles

  3. Lean mass influences overnight changes in hydration, blood pressure and strength in community-dwelling older women.

    Science.gov (United States)

    Benton, Melissa J; Schlairet, Maura C

    2016-10-01

    We evaluated the hypothesis that greater lean mass promotes better overnight hydration, improved postural blood pressure and greater strength. Thirty women, aged 71 ± 0.9 years (mean ± SE), completed one measurement in a euhydrated state and another the following morning after an overnight fast. Measurements included hydration, lean mass, orthostatic blood pressure and strength. Participants were grouped by fat-free mass index (FFMI), with cut-points defined as low (blood pressure. On day 1, women with low FFMI experienced significant postural systolic blood pressure changes from sitting to standing (-11.3 ± 4.0 mmHg, p postural blood pressure and loss of strength that increases the risk for early morning falls.

  4. In vitro evaluation of influence of salivary contamination on the dentin bond strength of one-bottle adhesive systems

    Directory of Open Access Journals (Sweden)

    Nujella B.P Suryakumari

    2011-01-01

    Full Text Available Aim: To evaluate the effect of salivary contamination on the bond strength of one-bottle adhesive systems - (the V generation at various stages during the bonding procedure and to investigate the effect of the contaminant removing treatments on the recovery of bond strengths. Materials and Methods: In this study the V generation one-bottle system - (Adper Single Bond was tested. Fifty caries-free human molars with flat dentin surfaces were randomly divided into five groups of ten teeth each: Group I had 15 second etching with 35% Ortho Phosphoric acid, 15 second rinse and blot dried (Uncontaminated; Group II contaminated and blot dried; Group III contaminated and completely dried; Group IV contaminated, washed, blot dried; Group V contaminated, retched washed, and blot dried. The bonding agent was applied and resin composite (Z-100 3M ESPE was bonded to the treated surfaces using the Teflon mold. The specimens in each group were then subjected to shear bond strength testing in an Instron Universal testing machine at a crosshead speed of 1 mm / minute and the data were subjected to one way ANOVA for comparison among the groups (P<0.05. Results: There was a significant difference between the group that was dried with strong oil-free air after contamination (Group III and the other groups. When the etched surface was contaminated by saliva, there was no statistical difference between the just blot dry, wash, or the re-etching groups (Groups II, IV, V if the dentin surface was kept wet before priming. When the etched dentin surface was dried (Group III the shear bond strength decreased considerably. Conclusion: The bond strengths to the tooth structure of the recent dentin bonding agents are less sensitive to common forms of contamination than assumed. Re-etching without additional mechanical preparation is sufficient to provide or achieve the expected bond strength.

  5. Influence of Selected Factors on the Relationship between the Dynamic Elastic Modulus and Compressive Strength of Concrete.

    Science.gov (United States)

    Jurowski, Krystian; Grzeszczyk, Stefania

    2018-03-22

    In this paper, the relationship between the static and dynamic elastic modulus of concrete and the relationship between the static elastic modulus and compressive strength of concrete have been formulated. These relationships are based on investigations of different types of concrete and take into account the type and amount of aggregate and binder used. The dynamic elastic modulus of concrete was tested using impulse excitation of vibration and the modal analysis method. This method could be used as a non-destructive way of estimating the compressive strength of concrete.

  6. Influence of mechanical stress level in preliminary stress-corrosion testing on fatigue strength of a low-carbon steel

    International Nuclear Information System (INIS)

    Aleskerova, S.A.; Pakharyan, V.A.

    1978-01-01

    Effect of corrosion and mechanical factors of preliminary stress corrosion of a metal in its fatigue strength, has been investigated. Smooth cylindrical samples of 20 steel have been tested. Preliminary corrosion under stress has been carried out under natural sea conditions. It is shown that mechanical stresses in the case of preliminary corrosion affect fatigue strength of low-carbon steels, decreasing the range of limited durability and fatigue limit. This effect increases with the increase of stress level and agressivity of corrosive medium

  7. Influence of Selected Factors on the Relationship between the Dynamic Elastic Modulus and Compressive Strength of Concrete

    Science.gov (United States)

    Jurowski, Krystian; Grzeszczyk, Stefania

    2018-01-01

    In this paper, the relationship between the static and dynamic elastic modulus of concrete and the relationship between the static elastic modulus and compressive strength of concrete have been formulated. These relationships are based on investigations of different types of concrete and take into account the type and amount of aggregate and binder used. The dynamic elastic modulus of concrete was tested using impulse excitation of vibration and the modal analysis method. This method could be used as a non-destructive way of estimating the compressive strength of concrete. PMID:29565830

  8. Factors that influence outcomes in cochlear implantation in adults, based on patient related characteristics - a retrospective study

    NARCIS (Netherlands)

    Kraaijenga, Véronique J C; Smit, Adriana L; Stegeman, Inge; Smilde, Jeanet J M; van Zanten, G A; Grolman, Wilko

    2016-01-01

    OBJECTIVE: Outcomes in speech perception following cochlear implantation in adults vary widely. Many studies have been carried out to identify and quantify factors that influence outcomes. This paper adds a new dimension to pre-existing literature. DESIGN: Single center retrospective cohort study.

  9. The influence of interleukin-7 receptor α-chain haplotypes on outcome after allogeneic hematopoietic cell transplantation

    DEFF Research Database (Denmark)

    Broux, B; Shamim, Z; Wang, T

    2014-01-01

    We investigated the influence of IL-7 receptor α-chain (IL-7Rα) gene haplotypes in donors on the outcome of haematopoietic cell transplantation (HCT). Unlike the association between single donor SNPs and HCT outcome found previously, only trends towards association were found here, due to 'diluti...

  10. Influence of spinal sagittal alignment, body balance, muscle strength, and physical ability on falling of middle-aged and elderly males.

    Science.gov (United States)

    Imagama, Shiro; Ito, Zenya; Wakao, Norimitsu; Seki, Taisuke; Hirano, Kenichi; Muramoto, Akio; Sakai, Yoshihito; Matsuyama, Yukihiro; Hamajima, Nobuyuki; Ishiguro, Naoki; Hasegawa, Yukiharu

    2013-06-01

    Risk factors for falling in elderly people remain uncertain, and the effects of spinal factors and physical ability on body balance and falling have not been examined. The objective of this study was to investigate how factors such as spinal sagittal alignment, spinal range of motion, body balance, muscle strength, and gait speed influence falling in the prospective cohort study. The subjects were 100 males who underwent a basic health checkup. Balance, SpinalMouse(®) data, grip strength, back muscle strength, 10-m gait time, lumbar lateral standing radiographs, body mass index, and fall history over the previous year were examined. Platform measurements of balance included the distance of movement of the center of pressure (COP) per second (LNG/TIME), the envelopment area traced by movement of the COP (E AREA), and the LNG/E AREA ratio. The thoracic/lumbar angle ratio (T/L ratio) and sagittal vertical axis (SVA) were used as an index of sagittal balance. LNG/TIME and E AREA showed significant positive correlations with age, T/L ratio, SVA, and 10-m gait time; and significant negative correlations with lumbar lordosis angle, sacral inclination angle, grip strength and back muscle strength. Multiple regression analysis showed significant differences for LNG/TIME and E AREA with T/L ratio, SVA, lumbar lordosis angle and sacral inclination angle (R (2) = 0.399). Twelve subjects (12 %) had experienced a fall over the past year. Age, T/L ratio, SVA, lumbar lordosis angle, sacral inclination angle, grip strength, back muscle strength, 10-m gait time, height of the intervertebral disc, osteophyte formation in radiographs and LNG/E AREA differed significantly between fallers and non-fallers. The group with SVA > 40 mm (n = 18) had a significant higher number of subjects with a single fall (6 single fallers/18: p = 0.0075) and with multiple falls (4 multiple fallers/18: p = 0.0095). Good spinal sagittal alignment, muscle strength and 10-m gait speed improve body balance

  11. Significant influence of the primary liver disease on the outcomes of hepatic retransplantation.

    LENUS (Irish Health Repository)

    Qasim, A

    2012-02-01

    BACKGROUND: There are many indications for hepatic retransplantation. AIM: To identify factors influencing retransplantation needs and outcomes. PATIENTS AND METHODS: Retransplantation records from January 1993 to March 2005 were analysed. Patient and disease characteristics and survival outcomes for retransplantation were compared between various groups. RESULTS: Totally, 286 primary and 42 hepatic retransplantations were performed. Retransplantation indications included primary sclerosing cholangitis (PSC), primary biliary cirrhosis, chronic hepatitis C (HCV), chronic active hepatitis (CAH), and alcohol-related disease. Mean follow-up post-retransplantation was 31 +\\/- 9 months. Actuarial patient survival at 3 months, 1 year, 3 years, 5 years, and at the end of study was 71.4, 69, 59.5, 54.7, and 50%, respectively. Early and late retransplantation had 1-year survival of 73 and 68.5%, respectively. Retransplantation need was significantly higher for PSC, HCV, and CAH. CONCLUSIONS: Hepatic retransplantation remains a successful salvage option for transplant complications; however, its need is significantly influenced by the primary liver disease.

  12. Results after laparoscopic partial splenectomy for children with hereditary spherocytosis: Are outcomes influenced by genetic mutation?

    Science.gov (United States)

    Pugi, Jakob; Carcao, Manuel; Drury, Luke J; Langer, Jacob C

    2018-05-01

    Laparoscopic partial splenectomy (LPS) theoretically maintains long-term splenic immune function for children with hereditary spherocytosis (HS). Our goal was to review our results after LPS and to determine if specific genetic mutations influence outcome. All children with HS undergoing LPS between 2005 and 2016 were reviewed. Thirty-one children underwent LPS (16 male) at a median age of 9 (range 2-18) years. All experienced an increase in hemoglobin and decrease in reticulocyte count early after LPS and at last follow-up. Twenty-two were sent for genetic analysis. Mutations in α-spectrin, β-spectrin, and Ankyrin were identified in 6, 5, and 11 patients, respectively. Gene mutation was not correlated with complications, perioperative transfusion, length of hospital stay, or median hemoglobin, platelet, or reticulocyte counts. Three children required completion splenectomy at 10.9, 6.9, and 3.2years post-LPS, each with a different gene mutation. LPS is effective in reversing anemia and reducing reticulocytosis. So far less than 10% have required completion splenectomy, and those children did benefit from delaying the risks of asplenia. In this preliminary analysis, genetic mutation did not influence outcome after LPS. A larger multicenter study is necessary to further investigate potential correlations with specific genetic mutations. Prognosis Study. IV. Copyright © 2018. Published by Elsevier Inc.

  13. Genetic influence on methadone treatment outcomes in patients undergoing methadone maintenance treatment for opioid addiction: a pilot study

    Directory of Open Access Journals (Sweden)

    Samaan Z

    2014-08-01

    Full Text Available Zainab Samaan,1–4 Monica Bawor,3,4 Brittany B Dennis,2,3 Carolyn Plater,5 Michael Varenbut,5 Jeffrey Daiter,5 Andrew Worster,5,6 David C Marsh,5,7 Charlie Tan,8 Dipika Desai,3 Lehana Thabane,2,9,10 Guillaume Pare11 1Department of Psychiatry and Behavioural Neurosciences, 2Department of Clinical Epidemiology and Biostatistics, 3Population Genomics Program, Chanchlani Research Centre, 4MiNDS Neuroscience Program, McMaster University, Hamilton, Ontario, Canada; 5Ontario Addiction Treatment Centres, Richmond Hill, Ontario, Canada; 6Department of Medicine, McMaster University, Hamilton, Ontario, Canada; 7Northern Ontario School of Medicine, Laurentian University, Sudbury, Ontario, Canada; 8Michael G. DeGroote School of Medicine, McMaster University, 9Biostatistics Unit, Centre for Evaluation of Medicine, 10System Linked Research Unit, 11Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada Introduction: Treatment of opioid addiction with methadone is effective; however, it is known to produce interindividual variability. This may be influenced in part by genetic variants, which can increase the initial risk of developing opioid addiction as well as explain differences in response to treatment. This pilot study aimed to assess the feasibility of conducting a full-scale genetic analysis to identify genes that predict methadone treatment outcomes in this population. Methods: This was a cross-sectional observational study of patients admitted to a methadone maintenance treatment program for opioid addiction. We obtained demographic and clinical characteristics in addition to blood and urine samples, for the assessment of treatment outcomes. Results: The recruitment process yielded 252 patients, representing a 20% recruitment rate. We conducted genetic testing based on a 99.6% rate of provision of DNA samples. The average retention in treatment was 3.4 years, and >50% of the participants reported psychiatric and

  14. The influence of tracheostomy timing on outcomes in trauma patients: A meta-analysis.

    Science.gov (United States)

    Cai, Shi-Qi; Hu, Jun-Wu; Liu, Dong; Bai, Xiang-Jun; Xie, Jie; Chen, Jia-Jun; Yang, Fan; Liu, Tao

    2017-04-01

    This study aims to assess the influence of tracheostomy timing on outcomes among trauma patients, including mortality, medical resource utility and incidence of pneumonia. A systematic review of the literature was conducted by internet search. Data were extracted from selected studies and analyzed using Stata to compare outcomes in trauma patients with early tracheostomy (ET) or late tracheostomy (LT)/prolonged intubation (PI). 20 studies met our inclusion criteria with 3305 patients in ET group and 4446 patients in LT/PI group. Pooled data revealed that mortality was not lower in trauma patients with ET compared to those with LT/IP. However, ET was found to be associated with a significantly reduced length of ICU and hospital stay, shorter MV duration and lower risk of pneumonia. Evidence of this meta-analysis supports the dimorphism in some clinical outcomes of trauma patients with different tracheostomy timing. Additional well-designed randomized controlled trials (RCTs) are needed to confirm it in future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Nutrition and Helicobacter pylori: Host Diet and Nutritional Immunity Influence Bacterial Virulence and Disease Outcome

    Directory of Open Access Journals (Sweden)

    Kathryn P. Haley

    2016-01-01

    Full Text Available Helicobacter pylori colonizes the stomachs of greater than 50% of the world’s human population making it arguably one of the most successful bacterial pathogens. Chronic H. pylori colonization results in gastritis in nearly all patients; however in a subset of people, persistent infection with H. pylori is associated with an increased risk for more severe disease outcomes including B-cell lymphoma of mucosal-associated lymphoid tissue (MALT lymphoma and invasive adenocarcinoma. Research aimed at elucidating determinants that mediate disease progression has revealed genetic differences in both humans and H. pylori which increase the risk for developing gastric cancer. Furthermore, host diet and nutrition status have been shown to influence H. pylori-associated disease outcomes. In this review we will discuss how H. pylori is able to create a replicative niche within the hostile host environment by subverting and modifying the host-generated immune response as well as successfully competing for limited nutrients such as transition metals by deploying an arsenal of metal acquisition proteins and virulence factors. Lastly, we will discuss how micronutrient availability or alterations in the gastric microbiome may exacerbate negative disease outcomes associated with H. pylori colonization.

  16. Influence of Lumbar Lordosis on the Outcome of Decompression Surgery for Lumbar Canal Stenosis.

    Science.gov (United States)

    Chang, Han Soo

    2018-01-01

    Although sagittal spinal balance plays an important role in spinal deformity surgery, its role in decompression surgery for lumbar canal stenosis is not well understood. To investigate the hypothesis that sagittal spinal balance also plays a role in decompression surgery for lumbar canal stenosis, a prospective cohort study analyzing the correlation between preoperative lumbar lordosis and outcome was performed. A cohort of 85 consecutive patients who underwent decompression for lumbar canal stenosis during the period 2007-2011 was analyzed. Standing lumbar x-rays and 36-item short form health survey questionnaires were obtained before and up to 2 years after surgery. Correlations between lumbar lordosis and 2 parameters of the 36-item short form health survey (average physical score and bodily pain score) were statistically analyzed using linear mixed effects models. There was a significant correlation between preoperative lumbar lordosis and the 2 outcome parameters at postoperative, 6-month, 1-year, and 2-year time points. A 10° increase of lumbar lordosis was associated with a 5-point improvement in average physical scores. This correlation was not present in preoperative scores. This study showed that preoperative lumbar lordosis significantly influences the outcome of decompression surgery on lumbar canal stenosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Shape of Thyroid Cartilage Influences Outcome of Montgomery Medialization Thyroplasty: A Gender Issue.

    Science.gov (United States)

    Desuter, Gauthier; Henrard, Sylvie; Van Lith-Bijl, Julie T; Amory, Avigaëlle; Duprez, Thierry; van Benthem, Peter Paul; Sjögren, Elisabeth

    2017-03-01

    This study aimed to determine whether the shape of the thyroid cartilage and gender influence voice outcomes after a Montgomery thyroplasty implant system (MTIS). A retrospective cohort study was performed on 20 consecutive patients who underwent MTIS. Voice outcome variables were the relative decrease in Voice Handicap Index (%) and the absolute increase in maximum phonation time (MPT) (in seconds). Material variables were the angle between the thyroid cartilage laminae (α-angle), the size of the prosthesis, and a combination of both (the α-ratio). Continuous variables were analyzed using medians and were compared between groups using the Mann-Whitney U test. Factors associated with the outcome variables were assessed by multivariable linear regression. A Pearson coefficient was calculated between material variables. The absolute increase in MPT between the pre- and postoperative period was significantly different between men and women, with a median absolute increase of 11.0 seconds for men and of 1.3 seconds for women (P gender issue that needs to be further studied and eventually tackled. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  18. The Influence of Hearing Aid Use on Outcomes of Children With Mild Hearing Loss.

    Science.gov (United States)

    Walker, Elizabeth A; Holte, Lenore; McCreery, Ryan W; Spratford, Meredith; Page, Thomas; Moeller, Mary Pat

    2015-10-01

    This study examined the effects of consistent hearing aid (HA) use on outcomes in children with mild hearing loss (HL). Five- or 7-year-old children with mild HL were separated into 3 groups on the basis of patterns of daily HA use. Using analyses of variance, we compared outcomes between groups on speech and language tests and a speech perception in noise task. Regression models were used to investigate the influence of cumulative auditory experience (audibility, early intervention, HA use) on outcomes. Full-time HA users demonstrated significantly higher scores on vocabulary and grammar measures compared with nonusers. There were no significant differences between the 3 groups on articulation or speech perception measures. After controlling for the variance in age at confirmation of HL, level of audibility, and enrollment in early intervention, only amount of daily HA use was a significant predictor of grammar and vocabulary. The current results provide evidence that children's language development benefits from consistent HA use. Nonusers are at risk in areas such as vocabulary and grammar compared with other children with mild HL who wear HAs regularly. Service providers should work collaboratively to encourage consistent HA use.

  19. The Influence of Cardiac Risk Factor Burden on Cardiac Stress Test Outcomes.

    Science.gov (United States)

    Schrock, Jon W; Li, Morgan; Orazulike, Chidubem; Emerman, Charles L

    2011-06-01

    Chest pain is the most common admission diagnosis for observation unit patients. These patients often undergo cardiac stress testing to further risk stratify for coronary artery disease (CAD). The decision of whom to stress is currently based on clinical judgment. We sought to determine the influence of cardiac risk factor burden on cardiac stress test outcome for patients tested from an observation unit, inpatient or outpatient setting. We performed a retrospective observational cohort study for all patients undergoing stress testing in our institution from June 2006 through July 2007. Cardiac risk factors were collected at the time of stress testing. Risk factors were evaluated in a summative fashion using multivariate regression adjusting for age and known coronary artery disease. The model was tested for goodness of fit and collinearity and the c statistic was calculated using the receiver operating curve. A total of 4026 subjects were included for analysis of which 22% had known CAD. The rates of positive outcome were 89 (12.0%), 95 (12.6%), and 343 (16.9%) for the OU, outpatients, and hospitalized patients respectively. While the odds of a positive test outcome increased for additional cardiac risk factors, ROC curve analysis indicates that simply adding the number of risk factors does not add significant diagnostic value. Hospitalized patients were more likely to have a positive stress test, OR 1.41 (1.10 - 1.81). Our study does not support basing the decision to perform a stress test on the number of cardiac risk factors.

  20. Influence of new societal factors on neovascular age-related macular degeneration outcomes.

    Science.gov (United States)

    Giocanti-Aurégan, Audrey; Chbat, Elige; Darugar, Adil; Morel, Christophe; Morin, Bruno; Conrath, John; Devin, François

    2018-02-01

    To assess the impact of unstudied societal factors for neovascular age-related macular degeneration (nAMD) on functional outcomes after anti-VEGFs. Charts of 94 nAMD patients treated in the Monticelli-Paradis Centre, Marseille, France, were reviewed. Phone interviews were conducted to assess societal factors, including transportation, living status, daily reading and social security scheme (SSS). Primary outcome was the impact of family support and disease burden on functional improvement in nAMD. Between baseline and month 24 (M24), 42.4% of the variability in best-corrected visual acuity (BCVA) was explained by the cumulative effect of the following societal factors: intermittent out-patient follow-up, marital status, daily reading, transportation type, commuting time. No isolated societal factor significantly correlated with ETDRS BCVA severity at M24. A trend to correlation was observed between the EDTRS score at M24 and the SSS (P = 0.076), economic burden (P = 0.075), time between diagnosis and treatment initiation (P = 0.070). A significant correlation was found for the disease burdensome on the patient (P = 0.034) and low vision rehabilitation (P = 0.014). Societal factors could influence functional outcomes in nAMD patients treated with anti-VEGFs. They could contribute to the healing process or sustain disease progression.

  1. In vitro Assessment of Influence of Various Bleaching Protocols on the Strength of Ceramic Orthodontic Brackets bonded to Bleached Tooth Surface: A Comparative Study.

    Science.gov (United States)

    Iska, Divya; Devanna, Raghu; Singh, Madhvi; Chitumalla, Rajkiran; Balasubramanian, Sai C Bala; Goutam, Manish

    2017-12-01

    Esthetics is one of the common issues because of which patients consult dental orthodontic treatment. Two ways of tooth bleaching are available these days, which includes in-office bleach and home bleach. Various bleaching protocols are available these days for treating the tooth surfaces. Hence, we planned the present study for investigating the impact of various intracoronal bleaching protocols on shear bond strength of ceramic brackets bonded to tooth surface after bleaching. The present study included assessment of 100 extracted maxillary central incisors with the integrated buccal surface. A resin block was made and individual teeth were embedded in each block. Root canal therapy procedure was performed in all the teeth, after which 2 mm short of tooth apex up to the level of cementoenamel junction, removal of the root canal filling was done. All the samples were broadly divided into four study groups with 25 samples in each group. Bleaching procedure was carried in all the samples intracoronally followed by testing of shear bond strength using universal force testing machine. Following the modified adhesive remnant index (AI), assessment of remaining adhesive on the brackets was done. All the results were compiled and analyzed by Statistical Package for the Social Sciences (SPSS) software version 17.0. In the control group, mean shear bond strength was found to be 17.9 MPa. While comparing the carbamide peroxide (CP) group with sodium perborate study group, we observed a statistically significant difference. Nonsignificant results were obtained while comparing the shear bond strength in between sodium perborate group and hydrogen peroxide (HP) group. Intracoronal bleaching does affect the shear bond strength of ceramic brackets. Sodium perborate bleaching influences shear bond strength more strongly than other bleaching agents such as CP and HP. In patients undergoing orthodontic treatment, HP is a preferred agent where bleaching has to be followed by

  2. The Influence of Resistance Training Experience on the Between-Day Reliability of Commonly Used Strength Measures in Male Youth Athletes.

    Science.gov (United States)

    Weakley, Jonathon J S; Till, Kevin; Darrall-Jones, Joshua; Roe, Gregory A B; Phibbs, Padraic J; Read, Dale B; Jones, Ben L

    2017-07-01

    Weakley, JJS, Till, K, Darrall-Jones, J, Roe, GAB, Phibbs, PJ, Read, DB, and Jones, BL. The influence of resistance training experience on the between-day reliability of commonly used strength measures in male youth athletes. J Strength Cond Res 31(7): 2005-2010, 2017-The purpose of this study was to determine the between-day reliability of commonly used strength measures in male youth athletes while considering resistance training experience. Data were collected on 25 male athletes over 2 testing sessions, with 72 hours rest between, for the 3 repetition maximum (3RM) front squat, chin-up, and bench press. Subjects were initially categorized by resistance training experience (inexperienced; 6-12 months, experienced; >2 years). The assessment of the between-day reliability (coefficient of variation [CV%]) showed that the front squat (experienced: 2.90%; inexperienced: 1.90%), chin-up (experienced: 1.70%; inexperienced: 1.90%), and bench press (experienced: 4.50%; inexperienced: 2.40%) were all reliable measures of strength in both groups. Comparison between groups for the error of measurement for each exercise showed trivial differences. When both groups were combined, the CV% for the front squat, bench press, and chin-up were 2.50, 1.80, and 3.70%, respectively. This study provides scientists and practitioners with the between-day reliability reference data to determine real and practical changes for strength in male youth athletes with different resistance training experience. Furthermore, this study demonstrates that 3RM front squat, chin-up, and bench press are reliable exercises to quantify strength in male youth athletes.

  3. [Influence of Attachment Style on the Outcome of Bariatric Surgery - A Pilot Study].

    Science.gov (United States)

    Appel, Johanna Elisabeth; Ift, Franziska; Kißler, Hermann; Kloos, Christof; Lehmann, Thomas; Strauß, Bernhard; Wick, Katharina

    2016-12-01

    Background: Bariatric surgery can lower body weight and comorbidities. Different factors might influence the outcome of this treatment. This pilot study examines whether patients' attachment style can influence surgical outcome. Methods: The sample consisted of 32 patients (f=24; m=8; BMI preoperative=47,8 kg/m 2 ±5,2; age=53±9,84) who underwent a laparoscopic sleeve gastrectomy. The following variables were assessed pre- and postoperatively via questionnaires: quality of life (BAROS), self esteem (SES), depression, anxiety, psychological distress (SCL-90R), feelings of hunger, cognitive control, irritated eating behaviour (FEV) and weight related variables (BMI, EWL%, EBL%, TBL). Attachment style was determined postoperatively using the BPQE. Results: None of the participating patients suffered from a binge eating disorder. There was no significant difference of the BMI at any time between the 12 securely attached (SA) patients and the 19 insecurely attachted (IA) patients. Compared to the SA patients IA patients preoperatively showed lower outcomes in variables concerning eating behaviour and mental health. Comparing the 2 groups postoperatively the IA patients achieved lower levels in variables concerning mental health than SA patients and did not reach the preoperative values of the SA patients. Both groups benefited from surgery related to weight loss, mental health and eating behaviour. There was no difference found in the development from pre- to postoperative between SA and IA patients. Discussion & Conclusion: Patients profit by a bariatric intervention independent of their attachment style. By evaluating the attachment style, it could be possible to individually optimize pre- and postoperative patients support in order to gain more effective surgery results. Follow up studies extended to multi-site assessment are required. © Georg Thieme Verlag KG Stuttgart · New York.

  4. Influence of Molarity and Chemical Composition on the Development of Compressive Strength in POFA Based Geopolymer Mortar

    Directory of Open Access Journals (Sweden)

    S. M. Alamgir Kabir

    2015-01-01

    Full Text Available The investigation concerns the use of the optimum mix proportion of two locally available pozzolanic waste materials, namely, ground granulated blast furnace slag (GGBS and palm oil fuel ash (POFA, together with metakaolin (MK as binders. In addition, another local waste material, manufactured sand (M-sand, was used as a replacement for conventional sand in the development of green geopolymer mortar. Twenty-four mortar mixtures were designed with varying binder contents and alkaline activators. The oven dry curing was also kept consistent for all the mix proportions at a temperature of 65°C for 24 hours. The highest 28-day compressive strength of about 48 MPa was obtained for the mortar containing 20% of MK, 35% of GGBS, and 45% of POFA. The increment of MK beyond 20% leads to reduction of the compressive strength. The GGBS replacement beyond 35% also reduced the compressive strength. The entire specimen achieved average 80% of the 28-day strength at the age of 3 days. The density decreased with the increase of POFA percentage. The finding of this research by using the combination of MK, GGBS, and POFA as binders to wholly replace conventional ordinary Portland cement would lead to alternate eco-friendly geopolymer matrix.

  5. Influence of Thermal Annealing and a Glass Coating on the Strength of Soda-Lime-Silicate Glass

    Science.gov (United States)

    2017-11-01

    7. Fletcher PC, Tillman JJ . Effect of silicone quenching and acid polishing on the strength of glass. J Am Ceram Soc. 1964;47(8):379–382. 8...advanced ceramics at ambient temperature. West Conshohocken (PA): ASTM International; 2015. 14. Swab JJ , Thies SR, Wright JC, Shoenstein JA, Patel PJ

  6. Influence of Anterior Cruciate Ligament Tear on Thigh Muscle Strength and Hamstring-to-Quadriceps Ratio: A Meta-Analysis.

    Science.gov (United States)

    Kim, Hyun-Jung; Lee, Jin-Hyuck; Ahn, Sung-Eun; Park, Min-Ji; Lee, Dae-Hee

    2016-01-01

    Theoretical compensation after anterior cruciate ligament (ACL) tear could cause quadriceps weakness and hamstring activation, preventing anterior tibial subluxation and affecting the expected hamstring-to-quadriceps ratio. Although quadriceps weakness often occurs after ACL tears, it remains unclear whether hamstring strength and hamstring-to-quadriceps ratio increase in ACL deficient knees. This meta-analysis compared the isokinetic muscle strength of quadriceps and hamstring muscles, and the hamstring-to-quadriceps ratio, of the injured and injured limbs of patients with ACL tears. This meta-analysis included all studies comparing isokinetic thigh muscle strengths and hamstring-to-quadriceps ratio in the injured and uninjured legs of patients with ACL tear, without or before surgery. Thirteen studies were included in the meta-analysis. Quadriceps and hamstring strengths were 22.3 N∙m (95% CI: 15.2 to 29.3 N∙m; Pratio was 4% greater in ACL deficient than in uninjured limbs (95% CI: 1.7% to 6.3%; Pratio in ACL deficient knees.

  7. The influence of removing sizing on strength and stiffness of conventional and high modulus E-glass fibres

    DEFF Research Database (Denmark)

    Petersen, Helga Nørgaard; Kusano, Yukihiro; Brøndsted, Povl

    2016-01-01

    Two types of E-glass fibres, a conventional and a high modulus where the last one in the following will be denoted as ECR-glass fibre, were investigated regarding density, diameter, stiffness and strength. The fibres were analysed as pristine and after sizing removal treatments. The sizing was re...

  8. Structure of the β-strength function in heavy nuclei and its influence on the β-delayed fission

    International Nuclear Information System (INIS)

    Wene, C.O.; Isosimow, I.N.; Naumow, Y.W.; Klapdor, H.V.

    1978-01-01

    The shape of the beta strength function Ssub(β) for neutron-rich nuclei is discussed. The structure of Ssub(β) is calculated microscopically for the GT-β-decay of 236 , 238 Pa and is shown to be decisive for the probability for β-delayed fission. (orig.) [de

  9. The Influence of Age-related Changes in Tactile Sensibility and Muscular Strength on Hand Function in Older Adult Females

    Directory of Open Access Journals (Sweden)

    Jun Murata

    2010-12-01

    Conclusion: These results suggested that the manual dexterity in the hand function was attenuated with increasing age. We considered that this attenuating effect was associated with a decline in tactile sensibility rather than a change in the muscular strength of the hand.

  10. Influence of various surface-conditioning methods on the bond strength of metal brackets to ceramic surfaces

    NARCIS (Netherlands)

    Schmage, P; Nergiz, [No Value; Herrmann, W; Ozcan, M; Nergiz, Ibrahim; �zcan, Mutlu

    With the increase in adult orthodontic treatment comes the need to find a reliable method for bonding orthodontic brackets onto metal or ceramic crowns and fixed partial dentures. In this study, shear bond strength and surface roughness tests were used to examine the effect of 4 different surface

  11. Soy Glycenin: Influence of pH and Ionic Strength on Solubility and Molecular Structure at Ambient Temperatures

    NARCIS (Netherlands)

    Lakemond, C.M.M.; Jongh, de H.H.J.; Hessing, M.; Gruppen, H.; Voragen, A.G.J.

    2000-01-01

    This study describes the relationship between the solubility of glycinin, a major soy protein, and its structural properties at a quaternary, tertiary, and secondary folding level under conditions representative for food products. When the ionic strength is lowered from 0.5 to 0.2 or 0.03, the basic

  12. Influence of political opposition and compromise on conservation outcomes in the Tongass National Forest, Alaska.

    Science.gov (United States)

    Beier, Colin M

    2008-12-01

    To understand how a highly contentious policy process influenced a major conservation effort, I examined the origins, compromises, and outcomes of the Alaska National Interest Lands Conservation Act of 1980 (ANILCA) for the Tongass National Forest. Tongass wilderness designation was among the most controversial issues in the ANILCA debate, and it faced strong opposition from influential lawmakers, land managers, and Alaska residents. To investigate the influence of this opposition on Tongass conservation outcomes, I conducted a gap analysis of Tongass reserves and a policy analysis of the ANILCA debate and traced the influence of specific interests through the amendments, negotiations, and resulting compromises needed to enact ANILCA. Overall, I found that Tongass reserves comprise a broadly representative cross-section of ecosystems and species habitats in southeastern Alaska. Redrawn reserve boundaries, industry subsidies, and special access regulations reflected compromises to minimize the impact of wilderness conservation on mining, timber, and local stakeholder interests, respectively. Fragmentation of the Admiralty Island National Monument-the most ecologically valuable and politically controversial reserve-resulted from compromises with Alaskan Native (indigenous peoples of Alaska) corporations and timber interests. Despite language to accommodate "reasonable access" to wilderness reserves, ongoing access limitations highlight the concerns of Alaska residents that opposed ANILCA several decades ago. More broadly, the Tongass case suggests that early and ambitious conservation action may offset strong political opposition; compromises needed to establish key reserves often exacerbate development impacts in unprotected areas; and efforts to minimize social conflicts are needed to safeguard the long-term viability of conservation measures.

  13. Responsiveness of the Countermovement Jump and Handgrip Strength to an Incremental Running Test in Endurance Athletes: Influence of Sex.

    Science.gov (United States)

    García-Pinillos, Felipe; Delgado-Floody, Pedro; Martínez-Salazar, Cristian; Latorre-Román, Pedro Á

    2018-03-01

    The present study analyzed the acute effects of an incremental running test on countermovement jump (CMJ) and handgrip strength performance in endurance athletes, considering the effect of post-exercise recovery time and sex. Thirty-three recreationally trained long-distance runners, 20 men and 13 women, participated voluntarily in this study. The participants performed the Léger test, moreover, the CMJ and handgrip strength tests were carried out before and after the running test and during different stages of recovery (at the 1st min of recovery (posttest1), 5th min of recovery (posttest2), and 10th min of recovery (posttest3)). Two-way analysis of variance revealed a significant improvement in the CMJ (pre-posttest1, p = 0.001) and handgrip strength (pre-posttest2, p = 0.017) during recovery time. The Pearson's Chi-2 test showed no significant relationship ( p ≥ 0.05) between sex and post-activation potentiation (PAP). A linear regression analysis pointed to heart rate recovery as a predictive factor of CMJ improvement (PAP). In conclusion, despite significant fatigue reached during the Léger test, the long-distance runners did not experience an impaired CMJ and handgrip strength performance, either men or women, achieving an improvement (PAP) in posttest conditions. The results obtained showed no significant relationship between sex and PAP. Moreover, significant effect of recovery after running at high intensity on CMJ performance and handgrip strength was found. Finally, the data suggest that PAP condition can be predicted by heart rate recovery in endurance runners.

  14. Influence of Anterior Cruciate Ligament Tear on Thigh Muscle Strength and Hamstring-to-Quadriceps Ratio: A Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Hyun-Jung Kim

    Full Text Available Theoretical compensation after anterior cruciate ligament (ACL tear could cause quadriceps weakness and hamstring activation, preventing anterior tibial subluxation and affecting the expected hamstring-to-quadriceps ratio. Although quadriceps weakness often occurs after ACL tears, it remains unclear whether hamstring strength and hamstring-to-quadriceps ratio increase in ACL deficient knees. This meta-analysis compared the isokinetic muscle strength of quadriceps and hamstring muscles, and the hamstring-to-quadriceps ratio, of the injured and injured limbs of patients with ACL tears. This meta-analysis included all studies comparing isokinetic thigh muscle strengths and hamstring-to-quadriceps ratio in the injured and uninjured legs of patients with ACL tear, without or before surgery. Thirteen studies were included in the meta-analysis. Quadriceps and hamstring strengths were 22.3 N∙m (95% CI: 15.2 to 29.3 N∙m; P<0.001 and 7.4 N∙m (95% CI: 4.3 to 10.5 N∙m; P<0.001 lower, respectively, on the injured than on the uninjured side. The mean hamstring-to-quadriceps ratio was 4% greater in ACL deficient than in uninjured limbs (95% CI: 1.7% to 6.3%; P<0.001. Conclusively, Decreases were observed in both the quadriceps and hamstring muscles of patients with ACL tear, with the decrease in quadriceps strength being 3-fold greater. These uneven reductions slightly increase the hamstring-to-quadriceps ratio in ACL deficient knees.

  15. Influence of socioeconomic factors on pregnancy outcome in women with structural heart disease.

    Science.gov (United States)

    van Hagen, Iris M; Baart, Sara; Fong Soe Khioe, Rebekah; Sliwa-Hahnle, Karen; Taha, Nasser; Lelonek, Malgorzata; Tavazzi, Luigi; Maggioni, Aldo Pietro; Johnson, Mark R; Maniadakis, Nikolaos; Fordham, Richard; Hall, Roger; Roos-Hesselink, Jolien W

    2018-05-01

    Cardiac disease is the leading cause of indirect maternal mortality. The aim of this study was to analyse to what extent socioeconomic factors influence the outcome of pregnancy in women with heart disease. The Registry of Pregnancy and Cardiac disease is a global prospective registry. For this analysis, countries that enrolled ≥10 patients were included. A combined cardiac endpoint included maternal cardiac death, arrhythmia requiring treatment, heart failure, thromboembolic event, aortic dissection, endocarditis, acute coronary syndrome, hospitalisation for cardiac reason or intervention. Associations between patient characteristics, country characteristics (income inequality expressed as Gini coefficient, health expenditure, schooling, gross domestic product, birth rate and hospital beds) and cardiac endpoints were checked in a three-level model (patient-centre-country). A total of 30 countries enrolled 2924 patients from 89 centres. At least one endpoint occurred in 645 women (22.1%). Maternal age, New York Heart Association classification and modified WHO risk classification were associated with the combined endpoint and explained 37% of variance in outcome. Gini coefficient and country-specific birth rate explained an additional 4%. There were large differences between the individual countries, but the need for multilevel modelling to account for these differences disappeared after adjustment for patient characteristics, Gini and country-specific birth rate. While there are definite interregional differences in pregnancy outcome in women with cardiac disease, these differences seem to be mainly driven by individual patient characteristics. Adjustment for country characteristics refined the results to a limited extent, but maternal condition seems to be the main determinant of outcome. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise

  16. Social Support Influences on Substance Abuse Outcomes among Sober Living House Residents with Low and Moderate Psychiatric Severity

    Science.gov (United States)

    Polcin, Douglas L.; Korcha, Rachael

    2017-01-01

    Social support and psychiatric severity are known to influence substance abuse. However, little is known about how their influences vary under different conditions. We aimed to study how different types of social support were associated with substance abuse outcomes among persons with low and moderate psychiatric severity who entered Sober Living…

  17. The Influence of High Drug Loading in Xanthan Tablets and Media with Different Physiological pH and Ionic Strength on Swelling and Release.

    Science.gov (United States)

    Mikac, Urša; Sepe, Ana; Baumgartner, Saša; Kristl, Julijana

    2016-03-07

    The formation of a gel coat around xanthan (Xan) tablets, empty or loaded with pentoxifylline (PF), and its release in media differing in pH and ionic strength by NMR, MR imaging, and two release methods were studied. The T1 and T2 NMR relaxation times in gels depend predominantly on Xan concentration; the presence of PF has negligible influence on them. It is interesting that the matrix swelling is primarily regulated by Xan despite high drug loading (25%, 50%). The gastric pH and high ionic strength of the media do not influence the position of the penetration and swelling fronts but do affect the erosion front and gel thickness. The different release profiles obtained in mixing and nonmixing in vitro methods are the consequence of matrix hydration level and erosion at the surface. In water and in diluted acid medium with low ionic strength, the main release mechanism is erosion, whereas in other media (pH 1.2, μ ≥ 0.20 M), anomalous transport dominates as was found out by fitting of measured data with theoretical model. Besides the in vitro investigation that mimics gastric conditions, mathematical modeling makes the product development more successful.

  18. Quality of life outcomes in women with endometriosis are highly influenced by recruitment strategies.

    Science.gov (United States)

    De Graaff, A A; Dirksen, C D; Simoens, S; De Bie, B; Hummelshoj, L; D'Hooghe, T M; Dunselman, G A J

    2015-06-01

    To what extent are outcome measures in endometriosis-related quality of life studies influenced by the setting in which patient recruitment is performed? Quality of life outcomes in women with endometriosis are highly influenced by recruitment strategies. Most studies on quality of life in women with endometriosis are conducted in tertiary care centres or patient associations. It is conceivable that the setting in which patient recruitment is performed influences the quality of life results. This has not been investigated before. Retrospective questionnaire based cohort study (part of the World Endometriosis Research Foundation (WERF) EndoCost study). The investigated women were recruited in three settings: a tertiary care centre for endometriosis (n = 135); five secondary care centres (n = 63); an endometriosis patient association (n = 291). The secondary and tertiary care population included women with a laparoscopic and/or histological diagnosis of endometriosis. The patient association population consisted of women with a self-reported diagnosis of surgically confirmed endometriosis. The populations did not differ in terms of age, co-morbidities and education level. Delay of diagnosis was the longest in the patient association (median 7 years) (tertiary care 2 years; secondary care 1.5 years) (P values were analysed as if the symptom was not present. Missing values never exceeded 10%, except for one value. Therefore, it can be expected that the effect of missing data on the outcome is negligible. Twenty-five patients belonged to more than one category. A sensitivity analysis showed that the influence of assigning patients to another category was limited. Outcomes regarding quality of life are highly influenced by recruitment strategy. None of the groups appeared to be a representative selection of the total population of women with endometriosis. An alternative strategy for creating a representative population for cost and quality of life studies is probably to

  19. Does increased salinity influence the competitive outcome of two producer species?

    Science.gov (United States)

    Venâncio, C; Anselmo, E; Soares, A; Lopes, I

    2017-02-01

    Within the context of global climate changes, it is expected that low-lying coastal freshwater ecosystems will face seawater intrusion with concomitant increase in salinity levels. Increased salinity may provoke disruption of competitive relationships among freshwater species. However, species may be capable of acclimating to salinity, which, in turn, may influence the resilience of ecosystems. Accordingly, this work aimed at assessing the effects of multigenerational exposure to low levels of salinity in the competitive outcome of two species of green microalgae: Raphidocelis subcapitata and Chlorella vulgaris. To attain this, three specific objectives were delineated: (1) compare the toxicity of natural seawater (SW) and NaCl (as a surrogate of SW) to the two microalgae, (2) determine the capacity of the two microalgae species to acclimate to low salinity levels, and (3) assess the influence of exposure to low salinity levels in the competitive outcome of the two microalgae. Results revealed SW to be slightly less toxic than NaCl for the two microalgae. The EC 25,72 h for growth rate was 4.63 and 10.3 mS cm -1 for R. subcapitata and 6.94 and 15.4 mS cm -1 for C. vulgaris, respectively for NaCl and SW. Both algae were capable of acclimating to low levels of salinity, but C. vulgaris seemed to acclimate faster than R. subcapitata. When exposed in competition, under control conditions, the growth rates of C. vulgaris were lower than those of R. subcapitata. However, C. vulgaris was capable of acquiring competitive advantage equaling or surpassing the growth rate of R. subcapitata with the addition of NaCl or SW, respectively. The multigenerational exposure to low levels of salinity influenced the competitive outcome of the two algae both under control and salinity exposure. These results suggest that long-term exposure to low salinity stress can cause shifts in structure of algae communities and, therefore, should not be neglected since algae are at the basis

  20. Examining the influence of injection speed and mould temperature on the tensile strength of polypropylene and ABS

    DEFF Research Database (Denmark)

    Aarøe, Esben Raahede; Blaimschein, Karl Stephan; Deker, Lasse

    This report is the final task of course “41738 Experimental Plastics Technology” in the three weeks period of June 2009 at DTU, IPL. The aim of this project has been to investigate the ultimate tensile strength behaviour of two different polymers, with different structural composition, by varying...... the injection speed and the mold temperature independently while keeping all other process parameters fixed. In addition the scaling from production of large to small geometries has been investigated by doing two parallel productions and test setups of respectively injection moulded and micro injection moulded...... specimens. After production and tensile testing the specimens were examined with a microscope to underpin conclusions from the tensile test data. It was experienced that the injection speed in general increased the the tensile strength by orienting the polymeric-chains lengthwise in the specimens and thus...

  1. The influence of using volcanic ash and lime ash as filler on compressive strength in self compacting concrete

    Science.gov (United States)

    Karolina, Rahmi; Panatap Simanjuntak, Murydrischy

    2018-03-01

    Self Compacting Concrete (SCC) is a technology which is developing today in which concrete solidifies by itself without using vibrator. Casting conventional concrete which has a lot of reinforcement bars sometimes finds difficulty in achieving optimal solidity. The method used to solve this problem is by using SCC technology. SCC was made by using filler, volcanic ash, and lime ash as the filling materials so that the concrete became more solid and hollow space could be filled up. The variation of using these two materials was 10%, 15%, 20%, and 25% of the cementitious mass and using 1% of superplasticizer from cementitious material. The supporting testing was done by using the test when the concrete was still fluid and when it was solid. Malleable concrete was tested by using EFNARC 2002 standard in slump flow test, v-funnel test, l-shaped box test, and j-ring test to obtain filling ability and passing ability. In this malleable lime concrete test, there was the decrease, compared with normal SCC concrete without adding volcanic ash and lime ash. Testing was also done in solid concrete in compressive strength, tensile strength, and concrete absorption. The result of the testing showed that the optimum tensile strength in Variation 1, without volcanic ash and lime ash – with 1% of superplasticizer was 39.556 MPa, the optimum tensile strength in Variation 1, without volcanic ash and lime ash- with 1% of super-plasticizer was 3.563 MPa, while the value of optimum absorption which occurred in Variation 5 (25% of volcanic ash + 25% of lime ash + 50% of cement + 1% of superplasticizer) was 1.313%. This was caused by the addition of volcanic ash and lime ash which had high water absorption.

  2. Influence of temporary cement contamination on the surface free energy and dentine bond strength of self-adhesive cements.

    Science.gov (United States)

    Takimoto, Masayuki; Ishii, Ryo; Iino, Masayoshi; Shimizu, Yusuke; Tsujimoto, Akimasa; Takamizawa, Toshiki; Ando, Susumu; Miyazaki, Masashi

    2012-02-01

    The surface free energy and dentine bond strength of self-adhesive cements were examined after the removal of temporary cements. The labial dentine surfaces of bovine mandibular incisors were wet ground with #600-grit SiC paper. Acrylic resin blocks were luted to the prepared dentine surfaces using HY Bond Temporary Cement Hard (HY), IP Temp Cement (IP), Fuji TEMP (FT) or Freegenol Temporary Cement (TC), and stored for 1 week. After removal of the temporary cements with an ultrasonic tip, the contact angle values of five specimens per test group were determined for the three test liquids, and the surface-energy parameters of the dentine surfaces were calculated. The dentine bond strengths of the self-adhesive cements were measured after removal of the temporary cements in a shear mode at a crosshead speed of 1.0mm/min. The data were subjected to one-way analysis of variance (ANOVA) followed by Tukey's HSD test. For all surfaces, the value of the estimated surface tension component γ(S)(d) (dispersion) was relatively constant at 41.7-43.3 mJm(-2). After removal of the temporary cements, the value of the γ(S)(h) (hydrogen-bonding) component decreased, particularly with FT and TC. The dentine bond strength of the self-adhesive cements was significantly higher for those without temporary cement contamination (8.2-10.6 MPa) than for those with temporary cement contamination (4.3-7.1 MPa). The γ(S) values decreased due to the decrease of γ(S)(h) values for the temporary cement-contaminated dentine. Contamination with temporary cements led to lower dentine bond strength. The presence of temporary cement interferes with the bonding performance of self-adhesive cements to dentine. Care should be taken in the methods of removal of temporary cement when using self-adhesive cements. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Influence of Abutment Design on Stiffness, Strength, and Failure of Implant-Supported Monolithic Resin Nano Ceramic (RNC) Crowns.

    Science.gov (United States)

    Joda, Tim; Huber, Samuel; Bürki, Alexander; Zysset, Philippe; Brägger, Urs

    2015-12-01

    Recent technical development allows the digital manufacturing of monolithic reconstructions with high-performance materials. For implant-supported crowns, the fixation requires an abutment design onto which the reconstruction can be bonded. The aim of this laboratory investigation was to analyze stiffness, strength, and failure modes of implant-supported, computer-assisted design and computer-aided manufacturing (CAD/CAM)-generated resin nano ceramic (RNC) crowns bonded to three different titanium abutments. Eighteen monolithic RNC crowns were produced and loaded in a universal testing machine under quasi-static condition according to DIN ISO 14801. With regard to the type of titanium abutment, three groups were defined: (1) prefabricated cementable standard; (2) CAD/CAM-constructed individualized; and (3) novel prefabricated bonding base. Stiffness and strength were measured and analyzed statistically with Wilcoxon rank sum test. Sections of the specimens were examined microscopically. Stiffness demonstrated high stability for all specimens loaded in the physiological loading range with means and standard deviations of 1,579 ± 120 N/mm (group A), 1,733 ± 89 N/mm (group B), and 1,704 ± 162 N/mm (group C). Mean strength of the novel prefabricated bonding base (group C) was 17% lower than of the two other groups. Plastic deformations were detectable for all implant-abutment crown connections. Monolithic implant crowns made of RNC seem to represent a feasible and stable prosthetic construction under laboratory testing conditions with strength higher than the average occlusal force, independent of the different abutment designs used in this investigation. © 2014 Wiley Periodicals, Inc.

  4. Investigation of the structural influence on the strength behaviour of TiC-Ni-Mo hard alloys

    International Nuclear Information System (INIS)

    Pilyankevich, A.N.; Shapoval, T.A.; Paderno, V.N.; Verkhovodov, P.A.; Vitryanyuk, V.K.

    The microstructure and fracture area of TiC-based hard alloys with nickel-molybdenum binder, in particular of TN-20, has been investigated with the aid of electron microscopy. It is shown that an analysis of the structure and of the behaviour of its constituents during fracture enables an assessment of the production process, of the strength and physical properties of the compact as well as of its usability under actual conditions of use. (author)

  5. Shear bond strength of resin composite bonded with two adhesives: Influence of Er: YAG laser irradiation distance

    Science.gov (United States)

    Shirani, Farzaneh; Birang, Reza; Malekipour, Mohammad Reza; Hourmehr, Zahra; Kazemi, Shantia

    2014-01-01

    Background: Dental surfaces prepared with different Er:YAG laser distance may have different characteristics compared with those prepared with conventional instruments. The aim of this study was to investigate the effect of Er:YAG laser irradiation distance from enamel and dentin surfaces on the shear bond strength of composite with self-etch and etch and rinse bonding systems compared with conventional preparation method. Materials and Methods: Two hundred caries-free human third molars were randomly divided into twenty groups (n = 10). Ten groups were designated for enamel surface (E1-E10) and ten for dentin surface (D1-D10). Er: YAG laser (2940 nm) was used on the E1-E8 (240 mJ, 25 Hz) and D1-D8 (140 mJ, 30 Hz) groups at four different distances of 0.5 (standard), 2, 4 and 11 mm. Control groups (E9, E10, D9 and D10) were ground with medium grit diamond bur. The enamel and dentin specimens were divided into two subgroups that were bonded with either Single Bond or Clearfil SE Bond. Resin composite (Z100) was dispensed on prepared dentin and enamel. The shear bond strengths were tested using a universal testing machine. Data were analyzed by SPSS12 statistical software using three way analysis of variance, Tukey and independent t-test. P enamel and dentin substrates (P enamel surfaces (in both bonding agent subgroups) and on dentin surfaces (in the Single Bond subgroup). Conclusion: Laser irradiation decreases shear bond strength. Irradiation distance affects shear bond strength and increasing the distance would decrease the negative effects of laser irradiation. PMID:25540665

  6. The Influence of No-Primer Adhesives and Anchor Pylons Bracket Bases on Shear Bond Strength of Orthodontic Brackets

    Directory of Open Access Journals (Sweden)

    Andrea Scribante

    2013-01-01

    Full Text Available Objective. The aim of this study was to compare the shear bond strength (SBS and adhesive remnant index (ARI scores of no-primer adhesives tested with two different bracket bases. Materials and Methods. 120 bovine permanent mandibular incisors were divided into 6 groups of 20 specimens. Two brackets (ODP with different bracket bases (anchor pylons and 80-gauge mesh were bonded to the teeth using a conventional adhesive (Transbond XT and two different no-primer adhesive (Ortho Cem; Heliosit systems. Groups were tested using an instron universal testing machine. SBS values were recorded. ARI scores were measured. SEM microphotographs were taken to evaluate the pattern of bracket bases. Statistical analysis was performed. ANOVA and Tukey tests were carried out for SBS values, whereas a chi-squared test was applied for ARI scores. Results. Highest bond strength values were reported with Transbond XT (with both pad designs, Ortho Cem bonded on anchor pylons and Heliosit on 80-gauge mesh. A higher frequency of ARI score of “3” was reported for Transbond XT groups. Other groups showed a higher frequency of ARI score “2” and “1.” Conclusion. Transbond XT showed the highest shear bond strength values with both pad designs.

  7. The influence of water on the strength of Neapolitan Yellow Tuff, the most widely used building stone in Naples (Italy)

    Science.gov (United States)

    Heap, Michael J.; Farquharson, Jamie I.; Kushnir, Alexandra R. L.; Lavallée, Yan; Baud, Patrick; Gilg, H. Albert; Reuschlé, Thierry

    2018-06-01

    Neapolitan Yellow Tuff (NYT) has been used in construction in Naples (Italy) since the Greeks founded the city—then called Neapolis—in the sixth century BCE. We investigate here whether this popular building stone is weaker when saturated with water, an issue important for assessments of weathering damage and monument preservation. To this end, we performed 28 uniaxial compressive strength measurements on dry and water-saturated samples cored from a block of the lithified Upper Member of the NYT. Our experiments show that the strength of the zeolite-rich NYT is systematically reduced when saturated with water (the ratio of wet to dry strength is 0.63). Complementary experiments show that two other common Neapolitan building stones—Piperno Tuff and the grey Campanian Ignimbrite (both facies of the Campanian Ignimbrite deposit devoid of zeolites)—do not weaken when wet. From these data, and previously published data for tuffs around the globe, we conclude that the water-weakening in NYT is a consequence of the presence of abundant zeolites (the block tested herein contains 46 wt.% of zeolites). These data may help explain weathering damage in NYT building stones (due to rainfall, rising damp, and proximity to the sea or water table) and the observed link between rainfall and landslides, rock falls, and sinkhole formation in Naples, and the weathering of other buildings built from zeolite-rich tuffs worldwide.

  8. Femur-bending properties as influenced by gravity. V - Strength vs. calcium and gravity in rats exposed for 2 weeks

    Science.gov (United States)

    Wunder, Charles C.; Cook, Kenneth M.; Watkins, Stanley R.; Moressi, William J.

    1987-01-01

    The dependence of gravitationally related changes in femur bone strength on the comparable changes in calcium content was investigated in rats exposed to chronic simulations of altered gravity from the 28th to 42nd day of age. Zero G was simulated by harness suspension and 3 G by centrifugation. Bone strength (S) was determined by bending (using modified quasi-static cantilever bending methods and equipment described by Wunder et al., 1977 and 1979) and Ca content (C, by mass pct) determined by atomic absorption spectrometry; results were compared with data obtained on both normal and harnessed control animals at 1 G. Multiple regression showed significant dependence of S upon earth's gravity, independent from C, for which there was no significant coefficient of partial regression. It is suggested that the lack of S/C correlation might have been due to the fact that considerable fraction of the calcium in these young, developing bones has not yet crystallized into the hydroxyapatite which provides strength.

  9. Plasma immersion ion implantation on 15-5PH stainless steel: influence on fatigue strength and wear resistance

    Science.gov (United States)

    Bonora, R.; Cioffi, M. O. H.; Voorwald, H. J. C.

    2017-05-01

    Surface improvement in steels is of great interest for applications in industry. The aim of this investigation is to study the effect of nitrogen ion implantation on the axial fatigue strength and wear resistance of 15-5 PH stainless steel. It is well know that electroplated coatings, which are used to improve abrasive wear and corrosion properties, affects negatively the fatigue strength. It is also important to consider requirements to reduce the use of coated materials with electroplated chromium and cadmium, that produce waste, which is harmful to health and environment. The HVOF (High velocity oxygen fuel) process provides hardness, wear strength and higher fatigue resistance in comparison to electroplated chromium. Plasma immersion ion implantation has been used to enhance the hardness, wear, fatigue and corrosion properties of metals and alloys. In the present research the fatigue life increased twice for 15-5 PH three hours PIII treated in comparison to base material. From the abrasive wear tests a lower pin mass reduction was observed, associated to the superficial treatments. The improvement of fatigue and mechanical performance is attributed to a combination of nitrides phase structure and compressive residual stresses during the PIII treatment.

  10. Plasma immersion ion implantation on 15-5PH stainless steel: influence on fatigue strength and wear resistance

    International Nuclear Information System (INIS)

    Bonora, R; Cioffi, M O H; Voorwald, H J C

    2017-01-01

    Surface improvement in steels is of great interest for applications in industry. The aim of this investigation is to study the effect of nitrogen ion implantation on the axial fatigue strength and wear resistance of 15-5 PH stainless steel. It is well know that electroplated coatings, which are used to improve abrasive wear and corrosion properties, affects negatively the fatigue strength. It is also important to consider requirements to reduce the use of coated materials with electroplated chromium and cadmium, that produce waste, which is harmful to health and environment. The HVOF (High velocity oxygen fuel) process provides hardness, wear strength and higher fatigue resistance in comparison to electroplated chromium. Plasma immersion ion implantation has been used to enhance the hardness, wear, fatigue and corrosion properties of metals and alloys. In the present research the fatigue life increased twice for 15-5 PH three hours PIII treated in comparison to base material. From the abrasive wear tests a lower pin mass reduction was observed, associated to the superficial treatments. The improvement of fatigue and mechanical performance is attributed to a combination of nitrides phase structure and compressive residual stresses during the PIII treatment. (paper)

  11. Influence of Porous Spherical-Shaped Hydroxyapatite on Mechanical Strength and Bioactive Function of Conventional Glass Ionomer Cement

    Directory of Open Access Journals (Sweden)

    Szu-Yu Chiu

    2017-01-01

    Full Text Available Glass-ionomer-cement (GIC is helpful in Minimal Intervention Dentistry because it releases fluoride ions and is highly biocompatible. The aim of this study is to investigate the mechanisms by which hydroxyapatite (HAp improves the mechanical strength and bioactive functioning of GIC when these materials are combined to make apatite ionomer cement (AIC. A conventional GIC powder was mixed with porous, spherical-HAp particles (HApS, crystalline HAp (HAp200 or one of two types of cellulose. The micro-compressive strengths of the additive particles were measured, and various specimens were evaluated with regard to their compressive strengths (CS, fluoride release concentrations (fluoride electrode and multi-element release concentrations. The AIC was found to release higher concentrations of fluoride (1.2 times and strontium ions (1.5 times compared to the control GIC. It was detected the more release of calcium originated from HApS than HAp200 in AIC. The CS of the AIC incorporating an optimum level of HAp was also significantly higher than that of the GIC. These results suggest that adding HAp can increase the release concentration of ions required for remineralization while maintaining the CS of the GIC. This effect does not result from a physical phenomenon, but rather from chemical reactions between the HAp and polyacrylic acid of GIC.

  12. The influence of older age on breast cancer treatment decisions and outcome

    International Nuclear Information System (INIS)

    Merchant, Thomas E.; McCormick, Beryl; Yahalom, Joachim; Borgen, Patrick

    1996-01-01

    Purpose: Information concerning the differences between older and younger women with breast cancer, treated with standard therapy, is lacking from many prospective series. The purpose of this study is to identify factors that influence treatment decisions and determine if women age 65 and older are treated differently than younger women. The outcomes of older women would then be compared to younger women to determine if treatment differences influence outcome. Methods and Materials: The records of 558 women with early invasive breast cancer who were treated with breast conserving surgery and radiation therapy were retrospectively reviewed. Four hundred thirty-two women under the age of 65 (range: 24-64) and 126 women age 65 and older (range: 65-85) were assessed for treatment differences including breast reexcision, extent of axillary dissection, extent of breast and nodal irradiation, and the use of chemotherapy or hormonal therapy. Differences in the treatment of the two groups were determined and the end points of local control, disease-free survival, and overall survival were compared. Median follow-up was 5.5 years. Results: The two treatment groups had identical pathologic TNM staging with the exception that 21% of the older age group and 5% of the younger age group did not undergo axillary dissection. Women age 65 and older were less likely to have a reexcision, extensive axillary dissection, chemotherapy, or nodal irradiation. They were more likely to receive hormonal therapy. Reexcision in older women was positively influenced by a family history of breast cancer and negatively influenced by a history of previous malignancy. None of the patients who were treated without an axillary dissection suffered a regional recurrence. Although local control was better in older patients, there were no differences in disease-free or overall survival for the two groups. Discussion: The findings of this study reveal that older patients have significant treatment

  13. Influence of field strength, coil type and image resolution on assessment of synovitis by unenhanced MRI - a comparison with contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Eshed, Iris [The Sheba Medical Center, Department of Diagnostic Imaging, Tel Hashomer (Israel); Tel Aviv University, Sackler School of Medicine, Tel Aviv (Israel); Krabbe, Simon; Axelsen, Mette; Pedersen, Susanne Juhl [Copenhagen University Hospital Glostrup, Copenhagen Center for Arthritis Research, Center for Rheumatology and Spine Diseases, Copenhagen (Denmark); Oestergaard, Mikkel [Copenhagen University Hospital Glostrup, Copenhagen Center for Arthritis Research, Center for Rheumatology and Spine Diseases, Copenhagen (Denmark); Copenhagen University Hospital Gentofte, Department of Rheumatology/C, Copenhagen (Denmark); Boeyesen, Pernille [Diakonhjemmet Hospital, Department of Rheumatology, Oslo (Norway); Moeller, Jakob M. [Copenhagen University Hospital at Herlev, Department of Radiology, Copenhagen (Denmark); Therkildsen, Flemming [Metropolitan University College, Copenhagen (Denmark); Madsen, Ole Rintek [Copenhagen University Hospital Gentofte, Department of Rheumatology/C, Copenhagen (Denmark)

    2015-04-01

    To explore if the reliability of synovitis assessment by unenhanced MRI is influenced by different MRI field-strengths, coil types and image resolutions in RA patients. Forty-one RA patients and 12 healthy controls underwent hand MRI (wrist and 2{sup nd}-5{sup th} metacarpophalangeal joints) at 4 different field-strengths (0.23 T/0.6 T/1.5 T/3.0 T) on the same day. Seven protocols using a STIR sequence with different field-strengths, coils (flex coils/dedicated phased-array extremity coils) and resolution were applied and scored blindly for synovitis (OMERACT-RAMRIS method). A 1.5 T post-contrast T1-weighted sequence was used as gold standard reference. Fair-good agreement (ICC=0.38-0.72) between the standard reference and the different STIR protocols (best agreement with extremity coil and small voxel size at 1.5 T). The accuracy for presence/absence of synovitis was very high per person (0.80-1.0), and moderate-high per joint (0.63-0.85), whereas exact agreements on scores were moderate (0.50-0.66). The intrareader agreement (15 patients and 3 controls) on presence/absence of synovitis was very high (0.87-1.0). Unenhanced MRI using STIR sequence is only moderately reliable for assessing hand synovitis in RA, when contrast-enhanced MRI is considered the gold standard reference. Contrast injection, field strength and coil type influence synovitis assessment, and should be considered before performing MRI in clinical trials and practice. (orig.)

  14. Influence of field strength, coil type and image resolution on assessment of synovitis by unenhanced MRI - a comparison with contrast-enhanced MRI

    International Nuclear Information System (INIS)

    Eshed, Iris; Krabbe, Simon; Axelsen, Mette; Pedersen, Susanne Juhl; Oestergaard, Mikkel; Boeyesen, Pernille; Moeller, Jakob M.; Therkildsen, Flemming; Madsen, Ole Rintek

    2015-01-01

    To explore if the reliability of synovitis assessment by unenhanced MRI is influenced by different MRI field-strengths, coil types and image resolutions in RA patients. Forty-one RA patients and 12 healthy controls underwent hand MRI (wrist and 2 nd -5 th metacarpophalangeal joints) at 4 different field-strengths (0.23 T/0.6 T/1.5 T/3.0 T) on the same day. Seven protocols using a STIR sequence with different field-strengths, coils (flex coils/dedicated phased-array extremity coils) and resolution were applied and scored blindly for synovitis (OMERACT-RAMRIS method). A 1.5 T post-contrast T1-weighted sequence was used as gold standard reference. Fair-good agreement (ICC=0.38-0.72) between the standard reference and the different STIR protocols (best agreement with extremity coil and small voxel size at 1.5 T). The accuracy for presence/absence of synovitis was very high per person (0.80-1.0), and moderate-high per joint (0.63-0.85), whereas exact agreements on scores were moderate (0.50-0.66). The intrareader agreement (15 patients and 3 controls) on presence/absence of synovitis was very high (0.87-1.0). Unenhanced MRI using STIR sequence is only moderately reliable for assessing hand synovitis in RA, when contrast-enhanced MRI is considered the gold standard reference. Contrast injection, field strength and coil type influence synovitis assessment, and should be considered before performing MRI in clinical trials and practice. (orig.)

  15. The Influence of Learning Management Technology to Student’s Learning Outcome

    Directory of Open Access Journals (Sweden)

    Taufiq Lilo Adi Sucipto

    2017-02-01

    Full Text Available The study examines the influence of learning management systems to the implementation of flipped classroom model in a vocational school in Indonesia. The flipped classroom is a relatively new educational model that inverts students’ time to study on lectures and time spent on homework. Despite studies have been conducted on the model, few addressed the impact of the use of a learning management system to the performance of students involved in such learning model particularly within Indonesian educational systems context. A quasi-experiment approach was applied to an experiment class and another control class. Upon the analysis, the results emphasized previously held research outcomes. The use of Edmodo learning management systems enhances students’ performance in the experiment class, relative to those of the control class.     Except where otherwise noted, content on this site is licensed under a Creative Commons Attribution 4.0 International License.

  16. Influence of different luting protocols on shear bond strength of computer aided design/computer aided manufacturing resin nanoceramic material to dentin.

    Science.gov (United States)

    Poggio, Claudio; Pigozzo, Marco; Ceci, Matteo; Scribante, Andrea; Beltrami, Riccardo; Chiesa, Marco

    2016-01-01

    The purpose of this study was to evaluate the influence of three different luting protocols on shear bond strength of computer aided design/computer aided manufacturing (CAD/CAM) resin nanoceramic (RNC) material to dentin. In this in vitro study, 30 disks were milled from RNC blocks (Lava Ultimate/3M ESPE) with CAD/CAM technology. The disks were subsequently cemented to the exposed dentin of 30 recently extracted bovine permanent mandibular incisors. The specimens were randomly assigned into 3 groups of 10 teeth each. In Group 1, disks were cemented using a total-etch protocol (Scotchbond™ Universal Etchant phosphoric acid + Scotchbond Universal Adhesive + RelyX™ Ultimate conventional resin cement); in Group 2, disks were cemented using a self-etch protocol (Scotchbond Universal Adhesive + RelyX™ Ultimate conventional resin cement); in Group 3, disks were cemented using a self-adhesive protocol (RelyX™ Unicem 2 Automix self-adhesive resin cement). All cemented specimens were placed in a universal testing machine (Instron Universal Testing Machine 3343) and submitted to a shear bond strength test to check the strength of adhesion between the two substrates, dentin, and RNC disks. Specimens were stressed at a crosshead speed of 1 mm/min. Data were analyzed with analysis of variance and post-hoc Tukey's test at a level of significance of 0.05. Post-hoc Tukey testing showed that the highest shear strength values (P adhesives) showed better shear strength values compared to self-adhesive resin cements. Furthermore, conventional resin cements used together with a self-etch adhesive reported the highest values of adhesion.

  17. The influence of lung function and muscular strength on the functional capacity of chronic obstructive pulmonary disease patients

    Directory of Open Access Journals (Sweden)

    Sérgio Leite Rodrigues

    2009-03-01

    Full Text Available Aim: To determine which variable (forced expiratory volume in 1 second (FEV1, partial pressure of oxygen in arterial blood (PaO2, nocturnal hypoxaemia and muscular strength of femoral quadriceps can predict the distance walked in the six-minute walk test (6MWT by COPD patients. Methods: A cross-sectional and observational study of thirty patients referred to a pulmonary rehabilita tion programme at a university hospital. Lung function was evaluated by spirometry, arterial blood gas analysis and nocturnal oximetry. Muscle function was evaluated by quadriceps strength and functional capacity by the 6MWT. Results: Bivariate regression analysis showed that quadriceps strength, was the only variable to correlate significantly with the distance walked in the 6MWT (p = 0.002, accounting for 38% of the 6MWT variance. The statistical relationship established for these variables was 1 kg of quadriceps strength equalled 5.9 metres walked in the 6MWT. Conclusions: Our results showed the importance of lower limb muscle strength in submaximal exercise testing. We conclude that femoral quadriceps muscle strength is the only one of the variables studied which can predict the distance COPD patients walk in the 6MWT. Resumo: Objectivo: Determinar que variável entre o volume expirado forçado no primeiro segundo (VEF1, a pressão parcial do oxigénio no sangue arterial (PaO2, a hipoxemia nocturna e a força muscular do quadricípite femoral pode predizer a distância percorrida no teste de caminhada de seis minutos (TC6 em doentes com DPOC. Doentes e métodos: Um estudo observacional do tipo transversal, envolvendo trinta doentes encaminhados a um programa de reabilitação pulmonar de um hospital universitário. A função pulmonar foi avaliada por espirometria, gasometria arterial e oximetria nocturna. A função muscular pela força muscular do quadricípite femoral e a avaliação da capacidade funcional pelo TC6

  18. Influence of sex on chronic obstructive pulmonary disease risk and treatment outcomes

    Directory of Open Access Journals (Sweden)

    Aryal S

    2014-10-01

    Full Text Available Shambhu Aryal,1 Enrique Diaz-Guzman,2 David M Mannino3 1Division of Pulmonary, Allergy and Critical Care Medicine, Duke University, Durham, NC, 2Division of Pulmonary, Allergy and Critical Care, University of Alabama, Birmingham, AL, 3Department of Preventive Medicine and Environmental Health, University of Kentucky, Lexington, KY, USA Abstract: Chronic obstructive pulmonary disease (COPD, one of the most common chronic diseases and a leading cause of death, has historically been considered a disease of men. However, there has been a rapid increase in the prevalence, morbidity, and mortality of COPD in women over the last two decades. This has largely been attributed to historical increases in tobacco consumption among women. But the influence of sex on COPD is complex and involves several other factors, including differential susceptibility to the effects of tobacco, anatomic, hormonal, and behavioral differences, and differential response to therapy. Interestingly, nonsmokers with COPD are more likely to be women. In addition, women with COPD are more likely to have a chronic bronchitis phenotype, suffer from less cardiovascular comorbidity, have more concomitant depression and osteoporosis, and have a better outcome with acute exacerbations. Women historically have had lower mortality with COPD, but this is changing as well. There are also differences in how men and women respond to different therapies. Despite the changing face of COPD, care providers continue to harbor a sex bias, leading to underdiagnosis and delayed diagnosis of COPD in women. In this review, we present the current knowledge on the influence of sex on COPD risk factors, epidemiology, diagnosis, comorbidities, treatment, and outcomes, and how this knowledge may be applied to improve clinical practices and advance research. Keywords: chronic obstructive lung disease, sex, smoking, comorbidity, sex bias

  19. Mucosal Perforation During Laparoscopic Heller Myotomy Has No Influence on Final Treatment Outcome.

    Science.gov (United States)

    Salvador, Renato; Spadotto, Lorenzo; Capovilla, Giovanni; Voltarel, Guerrino; Pesenti, Elisa; Longo, Cristina; Cavallin, Francesco; Nicoletti, Loredana; Ruol, Alberto; Valmasoni, Michele; Merigliano, Stefano; Costantini, Mario

    2016-12-01

    The aims of the study were (a) to examine the final outcome in patients experiencing accidental mucosal perforation during laparoscopic Heller myotomy with Dor fundoplication (LHD) and (b) to evaluate whether perforation episodes might influence the way in which surgeons subsequently approached the LHD procedure. We studied all consecutive patients that underwent LHD between 1992 and 2015. Patients were divided into two main groups: those who experienced an intraoperative mucosal perforation (group P) and those whose LHD was uneventful (group NP). Two additional groups were compared: group A, which consisted of patients operated by a given surgeon immediately before a perforation episode occurred, and group B, which included those operated immediately afterwards. Eight hundred seventy-five patients underwent LHD; a mucosal perforation was detected in 25 patients (2.9 %), which was found unrelated to patients' symptom's score and age, radiological stage, manometric pattern, or the surgeon's experience. The median postoperative symptom score was similar for the two groups as the failure rate: 92 failures in group NP (10.8 %) and 4 in group P (16 %) (p = 0.34); moreover, symptoms recurred in 2 patients of group A (10 %) and 3 patients of group B (15 %) (p = 0.9). Accidental perforation during LHD is infrequent and impossible to predict on the grounds of preoperative therapy or the surgeon's personal experience. Despite a longer surgical procedure and hospital stay, the outcome of LHD is much the same as for patients undergoing uneventful myotomy. A recent mucosal perforation does not influence the surgeon's subsequent performance.

  20. The influence of caregiver depression on adolescent mental health outcomes: findings from refugee settlements in Uganda.

    Science.gov (United States)

    Meyer, Sarah R; Steinhaus, Mara; Bangirana, Clare; Onyango-Mangen, Patrick; Stark, Lindsay

    2017-12-19

    Family-level predictors, including caregiver depression, are considered important influences on adolescent mental health. Adolescent depression and anxiety in refugee settings is known to be a significant public health concern, yet there is very limited literature from humanitarian settings focusing on the relationship between caregiver mental health and adolescent mental health. In the context of a larger study on child protection outcomes in refugee settings, researchers explored the relationship between caregiver depression and adolescent mental health in two refugee settlements, Kiryandongo and Adjumani, in Uganda. Adolescents between 13 and 17 and their caregivers participated in a household survey, which included measures of adolescent anxiety and depression, and caregiver depression. Analysis was conducted using multiple logistic regression models, and results were reported for the full sample and for each site separately. In Kiryandongo, a one-unit increase in a caregiver's depression score tripled the odds that the adolescent would have high levels of anxiety symptoms (AOR: 3.0, 95% CI: 1.4, 6.1), while in Adjumani, caregiver depression did not remain significant in the final model. Caregiver depression, gender and exposure to violence were all associated with higher symptoms of adolescent depression in both sites and the full sample, for example, a one unit increase in caregiver depression more than tripled the odds of higher levels of symptoms of adolescent depression (AOR: 3.6, 95% CI: 2.0, 6.2). Caregiver depression is a consistently significantly associated with adverse mental health outcomes for adolescents in this study. Adolescent well-being is significantly affected by caregiver mental health in this refugee context. Child protection interventions in humanitarian contexts do not adequately address the influence of caregivers' mental health, and there are opportunities to integrate child protection programming with prevention and treatment of

  1. Quality-of-Life Outcomes of Patients following Patellofemoral Stabilization Surgery: The Influence of Trochlear Dysplasia.

    Science.gov (United States)

    Hiemstra, Laurie Anne; Kerslake, Sarah; Lafave, Mark R

    2017-11-01

    Trochlear dysplasia is a well-described risk factor for recurrent patellofemoral instability. Despite its clear association with the incidence of patellofemoral instability, it is unclear whether the presence of high-grade trochlear dysplasia influences clinical outcome after patellofemoral stabilization. The purpose of this study was to assess whether trochlear dysplasia influenced patient-reported, disease-specific outcomes in surgically treated patellar instability patients, when risk factors were addressed in accordance with the à la carte surgical approach to the treatment of patellofemoral instability. The study design is of a case series. A total of 318 patellar stabilization procedures were performed during the study period. Of these procedures, 260 had adequate lateral radiographs and complete Banff Patellar Instability Instrument (BPII) scores available for assessment. A Pearson r correlation was calculated between four characteristics of trochlear dysplasia, the BPII total and the BPII symptoms, and physical complaints scores, a mean of 24 months following patellofemoral stabilization. Independent t -tests were performed between stratified trochlear dysplasia groups (no/low grade and high grade) and all BPII measures. There was a statistically significant correlation between measures of trochlear dysplasia and quality-of-life physical symptoms scores, an average of 2 years following patellofemoral stabilization surgery. The BPII symptoms and physical complaints domain score, as well as the individual weakness and stiffness questions, correlated with the classification of trochlear dysplasia as well as the presence of a trochlear bump ( p  patellofemoral stabilization surgery. There was a significant correlation between patient-reported physical symptoms after surgery and high-grade trochlear dysplasia. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  2. The Influence of Violence Victimization on Sexual Health Behaviors and Outcomes.

    Science.gov (United States)

    Latimer, Jennifer; Fleckman, Julia; Wallace, Maeve; Rountree, Michele; Theall, Katherine

    2017-05-01

    This study examines the implications of a history of personal violence on health and health behaviors. A secondary analysis of cross-sectional data involving adults (n = 214) from a semirural area in southern Louisiana between October 2008 and December 2010 was conducted to ascertain the association between a personal history of violence victimization and indicators of sexual health behaviors and outcomes: communication with sexual partners about HIV status, consistent condom use, and sexually transmitted infection (STI). While violence victimization is widely accepted as a risk factor for high-risk sex behavior, the mechanisms underlying violence victimization's influence on sexual health outcomes remain unclear. Bivariate analyses demonstrated a significant positive association between experience of physical abuse and lifetime history of STI. Surprisingly, respondents reporting lifetime physical violence were more than two times more likely to ask sexual partners about HIV status [odds ratio (OR) for physical attack = 2.23, 95% confidence intervals (CI) = 1.00-4.97; OR for physical injury = 4.60, 95% CI = 1.79-11.85]. Consistent condom use was not significantly associated with violence exposure in adjusted models. There was no evidence that communication with sexual partners mediated the relationship between experiences of violence and condom use. The link between personal history of violence and condom use may be mediated through alternative pathways beyond communication.

  3. The influence of smoking and other risk factors on the outcome after radiochemotherapy for anal cancer

    International Nuclear Information System (INIS)

    Mai, Sabine Kathrin; Welzel, Grit; Haegele, Verena; Wenz, Frederik

    2007-01-01

    Smoking is an important risk factor for the development of cancer. Smoking during radiochemotherapy therapy may have a negative influence on prognosis. We evaluated the effect of smoking during radiochemotherapy on the outcome for patients with anal cancer. Sixty-eight patients (34 smokers, 34 non-smokers) treated by radiochemotherapy for anal cancer were analysed. The effect of smoking during radiochemotherapy and other risk factors (gender, T- and N category, tumor site, dose, therapy protocol) on disease-specific survival (DSS), local control (LC) and colostomy free survival (CFS) was evaluated. There was a significant difference in age and male:female ratio between the two groups. With a median follow up of 22 months (max. 119) DSS, LC, and CFS were 88%, 84% and 84%. A significant difference in local control between smokers (S) and non-smokers (NS) was found (S 74% vs. NS 94%, p = .03). For DSS and CFS a difference in terms of outcome between smokers and non-smokers was seen (DSS: S 82% vs. NS 96%, p = .19, CFS: S 75% vs. 91%, p = .15), which did not reach statistical significance. In multivariate analyses only gender had a significant association with LC and T category with CFS. The other risk factors did not reach statistical significance. Even though our evaluation reached statistical significance only in univariate analysis, we suggest, that the role of smoking during radiochemotherapy for anal cancer should not be ignored. The potential negative effect on prognosis should be explained to patients before therapy

  4. Inherited Variants in Wnt Pathway Genes Influence Outcomes of Prostate Cancer Patients Receiving Androgen Deprivation Therapy

    Directory of Open Access Journals (Sweden)

    Jiun-Hung Geng

    2016-11-01

    Full Text Available Aberrant Wnt signaling has been associated with many types of cancer. However, the association of inherited Wnt pathway variants with clinical outcomes in prostate cancer patients receiving androgen deprivation therapy (ADT has not been determined. Here, we comprehensively studied the contribution of common single nucleotide polymorphisms (SNPs in Wnt pathway genes to the clinical outcomes of 465 advanced prostate cancer patients treated with ADT. Two SNPs, adenomatous polyposis coli (APC rs2707765 and rs497844, were significantly (p ≤ 0.009 and q ≤ 0.043 associated with both prostate cancer progression and all-cause mortality, even after multivariate analyses and multiple testing correction. Patients with a greater number of favorable alleles had a longer time to disease progression and better overall survival during ADT (p for trend ≤ 0.003. Additional, cDNA array and in silico analyses of prostate cancer tissue suggested that rs2707765 affects APC expression, which in turn is correlated with tumor aggressiveness and patient prognosis. This study identifies the influence of inherited variants in the Wnt pathway on the efficacy of ADT and highlights a preclinical rationale for using APC as a prognostic marker in advanced prostate cancer.

  5. The interrupted learner: How distractions during live and video lectures influence learning outcomes.

    Science.gov (United States)

    Zureick, Andrew H; Burk-Rafel, Jesse; Purkiss, Joel A; Hortsch, Michael

    2017-11-27

    New instructional technologies have been increasingly incorporated into the medical school learning environment, including lecture video recordings as a substitute for live lecture attendance. The literature presents varying conclusions regarding how this alternative experience impacts students' academic success. Previously, a multi-year study of the first-year medical histology component at the University of Michigan found that live lecture attendance was positively correlated with learning success, while lecture video use was negatively correlated. Here, three cohorts of first-year medical students (N = 439 respondents, 86.6% response rate) were surveyed in greater detail regarding lecture attendance and video usage, focusing on study behaviors that may influence histology learning outcomes. Students who reported always attending lectures or viewing lecture videos had higher average histology scores than students who employed an inconsistent strategy (i.e., mixing live attendance and video lectures). Several behaviors were negatively associated with histology performance. Students who engaged in "non-lecture activities" (e.g., social media use), students who reported being interrupted while watching the lecture video, or feeling sleepy/losing focus had lower scores than their counterparts not engaging in these behaviors. This study suggests that interruptions and distractions during medical learning activities-whether live or recorded-can have an important impact on learning outcomes. Anat Sci Educ 00: 000-000. © 2017 American Association of Anatomists. © 2017 American Association of Anatomists.

  6. INFLUENCE OF THE SAGITTAL BALANCE ON THE CLINICAL OUTCOME IN SPINAL FUSION

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    Marcela Almeida Campos Coutinho

    2016-03-01

    Full Text Available ABSTRACT Objective: Evaluates which radiographic parameters of the sagittal and spinopelvic balance influence the clinical and functional outcomes of a sample of patients undergoing spinal fusion. Methods: We studied 32 patients who underwent spinal fusion. Radiographs of the total spine were obtained from all patients. The clinical and functional parameters studied were analysis of pain by visual analogic scale (VAS and Oswestry and SRS-30 questionnaires. We analyzed the correlation between the clinical and functional parameters and radiographic parameters of the sagittal and spinopelvic balance. Results: There was no significant correlation between parameters pelvic incidence (PI, pelvic tilt (PT, lumbar lordosis (LL and difference between PI and LL (PI-LL and clinical parameters (p > 0.05 and r <0.2. Significant correlation were identified only between Sagittal Vertical Axis (SVA and Satisfaction with Treatment domain of SRS-30 (r = 0.402 e p = 0.023 and between thoracic kyphosis (TK and the total SRS-30 (r = 0.419 and p = 0.017. Conclusions: According to the study results, it was not possible to precisely characterize the role of the parameters of the sagittal and spinopelvic balance in the post-operative analysis of the clinical outcome of spinal fusion. There was a significant correlation only between SVA and the Satisfaction with Treatment domain of SRS-30 and between TK and total SRS-30.

  7. GOAL PROFILES, MENTAL TOUGHNESS AND ITS INFLUENCE ON PERFORMANCE OUTCOMES AMONG WUSHU ATHLETES

    Directory of Open Access Journals (Sweden)

    Garry Kuan

    2007-10-01

    Full Text Available This study examined the association between goal orientations and mental toughness and its influence on performance outcomes in competition. Wushu athletes (n = 40 competing in Intervarsity championships in Malaysia completed Task and Ego Orientations in Sport Questionnaire (TEOSQ and Psychological Performance Inventory (PPI. Using cluster analysis techniques including hierarchical methods and the non-hierarchical method (k-means cluster to examine goal profiles, a three cluster solution emerged viz. cluster 1 - high task and moderate ego (HT/ME, cluster 2 - moderate task and low ego (MT/LE and, cluster 3 - moderate task and moderate ego (MT/ME. Analysis of the fundamental areas of mental toughness based on goal profiles revealed that athletes in cluster 1 scored significantly higher on negative energy control than athletes in cluster 2. Further, athletes in cluster 1 also scored significantly higher on positive energy control than athletes in cluster 3. Chi-square (χ2 test revealed no significant differences among athletes with different goal profiles on performance outcomes in the competition. However, significant differences were observed between athletes (medallist and non medallist in self- confidence (p = 0.001 and negative energy control (p = 0.042. Medallist's scored significantly higher on self-confidence (mean = 21.82 ± 2.72 and negative energy control (mean = 19.59 ± 2.32 than the non-medallists (self confidence-mean = 18.76 ± 2.49; negative energy control mean = 18.14 ± 1.91.

  8. Tibial Sesamoid Position Influence on Functional Outcome and Satisfaction After Hallux Valgus Surgery.

    Science.gov (United States)

    Chen, Jerry Yongqiang; Rikhraj, Kiran; Gatot, Cheryl; Lee, Justine Yun Yu; Singh Rikhraj, Inderjeet

    2016-11-01

    During hallux valgus surgery, the abnormal position of the first metatarsal bone relative to the sesamoids is addressed. Our study aimed to investigate the influence of postoperative tibial sesamoid position (TSP) on functional outcome and patient satisfaction after hallux valgus surgery. Between February 2007 and November 2011, 250 patients who underwent hallux valgus surgery at our tertiary hospital were followed for 2 years after surgery. They were categorized into 2 groups based on Hardy and Clapham's TSP classification, recorded on postoperative weight-bearing anteroposterior (AP) radiographs: (1) normal (grades I-IV) and (2) outliers (grades V-VII). The mode TSP improved from grade VII preoperatively to grade IV postoperatively (P Hallux Metatarsophalangeal-Interphalangeal Scale was 6 (95% CI 2, 11) points higher in the normal group (P = .009). Patients in the outlier group were also more likely to be dissatisfied with the surgery performed when compared to the normal group (OR 3.881, 95% CI 1.689, 8.920, P = .001). We recommend correcting the TSP to grade of IV or less to improve functional outcome and satisfaction after hallux valgus surgery. Level III, retrospective comparative series. © The Author(s) 2016.

  9. [The influence of patient-controlled epidural analgesia on labor progress and neonatal outcome].

    Science.gov (United States)

    Rzepka, Rafał; Zukowski, Maciej; Michalczyk, Michał; Nikodemski, Tomasz; Torbé, Andrzej; Kwiatkowski, Sebastian; Mikołajek-Bedner, Wioletta; Czajka, Ryszard

    2012-02-01

    The aim of the study was to check the influence of patient control epidural analgesia on labor progress and neonatal outcome. 144 parturients were included into the clinical trial. In 73 cases patient control epidural analgesia was used and in 71 cases pethidine (meperidine) solution was given intravenously. Apgar score, umbilical artery pH, pain intensity the time of the first, second and third stage of labor the rate of episiotomy and uterine postpartum abrasions and the rate of caesarean sections and vaginal operative delivery were compared. The time of the second stage of labor was significantly longer in the study group (40.99 vs 26.49 min, p- neonatal outcome was comparable in both groups. There were no differences in the time of the first and the second stage of labor in primiparas and multiparas analyzed separately. Visual Analogue Score was lower in the study group (Ch(2)-12,48, p-0.25), especially in the subgroups of primiparas and multiparas. Patient control epidural analgesia does not affect the time of the first and second stage of labor, oxytocin augmentation of labor may be the reason of that. This method is a more effective way of relieving labor pain. An increase of operative delivery is not observed after patient control epidural analgesia on condition that low doses and concentrations of analgesic drugs are used.

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