971 resultados para pull-up testing


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Variations in the interleukin 4 receptor A (IL4RA) gene have been reported to be associated with atopy, asthma, and allergy, which may occur less frequently in subjects with type 1 diabetes (T1D). Since atopy shows a humoral immune reactivity pattern, and T1D results from a cellular (T lymphocyte) response, we hypothesised that alleles predisposing to atopy could be protective for T1D and transmitted less often than the expected 50% from heterozygous parents to offspring with T1D. We genotyped seven exonic single nucleotide polymorphisms (SNPs) and the -3223 C>T SNP in the putative promoter region of IL4RA in up to 3475 T1D families, including 1244 Finnish T1D families. Only the -3223 C>T SNP showed evidence of negative association (P=0.014). There was some evidence for an interaction between -3233 C>T and the T1D locus IDDM2 in the insulin gene region (P=0.001 in the combined and P=0.02 in the Finnish data set). We, therefore, cannot rule out a genetic effect of IL4RA in T1D, but it is not a major one.

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This paper uses a case study of a largely religiously non-practising group, working class loyalists in Northern Ireland, to explore the relationship between religion and ethnicity in divided societies. It finds that loyalists often turn to religion habitually in times of insecurity to provide justification for conflict. But religion does not just prop up deeper ethnic identities. Religion has meaning and content itself that is sometimes tension with oppositional ethnic identities and, in some cases, can transform them totally. This produces a complex set of relationships in which religion and ethnicity push and pull against one another in the lives of individuals, neither dominating fully over the other.

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Synopsis: Bonded-in rod timber joints off er several advantages over conventional types of joint, including high local force transfer, very stiff connections, and improved ?re and aesthetic properties since the connection is completely hidden in the insulating timber members. More recently, the use of ?bre reinforced polymer (FRP) as a connecting rod, alternative to steel rods, in bonded-in rod connections for timber structures has been investigated. However, the investigation into the behaviour of such joints is limited, in particular, connections involving basalt ?bre reinforced polymers (BFRP) bars - which is the primary focus of this research. This paper presents an experimental programme conducted to investigate the behaviour of bonded-in BFRP bars loaded parallel to the grain of glulam members. Tensile pull-out tests were conducted to examine the effect of bonded length and bond stress-slip on the structural capacity of the connection. An analytical design expression for predicting pull-out capacity is proposed and the results have been compared with some established design equations. It was found that pull-out load increased approximately linearly with the bonded length, up to maximum which occurred at a bonded length of 15 times the hole diameter, and did not increase beyond this bonded length. The most signi?cant failure modes were failure at the timber/adhesive interface followed by pullout of the BFRP rod. Increased bonded lengths resulted in higher bond slip values compared to lower equivalent bonded lengths. The proposed design model gave the best predictions of pull-out capacity compared with other existing models.

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Groundwater drawn from fluvioglacial sand and gravel aquifers form the principal source of drinking water in many part of central Western Europe. High population densities and widespread organic agriculture in these same areas constitute hazards that may impact the microbiological quality of many potable supplies. Tracer testing comparing two similarly sized bacteria (E.coli and P. putida) and the smaller bacteriophage (H40/1) with the response of non-reactive solute tracer (uranine) at the decametre scale revealed that all tracers broke through up to 100 times more quickly than anticipated using conventional rules of thumb. All microbiological tracer responses were less disperse than the solute, although bacterial peak relative concentrations consistently exceeded those of the solute tracer at one sampling location reflecting exclusion processes influencing micro biological tracer migration. Relative recoveries of H40/1 and E.coli proved consistent at both monitoring wells, while responses of H40/1 and P.putida differed. Examination of exposures of the upper reaches of the aquifer in nearby sand and gravel quarries revealed the aquifer to consist of laterally extensive layers of open framework (OW) gravel enveloped in finer grained gravelly sand. Granulometric analysis of these deposits suggested that the OW gravel was up to two orders of magnitude more permeable than the surrounding deposits giving rise to the preferential flow paths. By contrast fine grained lenses of silty sand within the OW gravels are suspected to play an important role in the exclusion processes that permit solutes to access them but exclude larger micro organisms.

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Gas-liquid processing in microreactors remains mostly restricted to the laboratory scale due to the complexity and expenditure needed for an adequate numbering-up with a uniform flow distribution. Here, the numbering-up is presented for multi-phase (gas-liquid) flow in microreactor suitable for a production capacity of kg/h. Based on the barrier channels concept, the barrier-based micro/milli reactor (BMMR) is designed and fabricated to deliver flow non-uniformity of less than 10%. The BMMR consists of eight parallel channels all operated in the Taylor flow regime and with a liquid flow rate up to 150. mL/min. The quality of the flow distribution is reported by studying two aspects. The first aspect is the influence of different viscosities, surface tensions and flow rates. The second aspect is the influence of modularity by testing three different reaction channels type: (1) square channels fabricated in a stainless steel plate, (2) square channels fabricated in a glass plate, and (3) circular channels (capillaries) made of stainless steel. Additionally, the BMMR is compared to that of a single channel regard the slug and bubble lengths and bubble generation frequency. The results pave the ground for bringing multi-phase flow in microreactor one step closer for large scale production via numbering-up. © 2012 Elsevier B.V.

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The behaviour of Basalt Fibre Reinforced Polymer (BFRP) loaded perpendicular to glulam timber elements was investigated. It was found that pull-out load increased approximately linearly with the bonded length up to maximum which occurred at a bonded length of 250 mm (~15 times the hole diameter) and did not increase beyond this bonded length. Failure mode of the samples was mostly shear fracture which was located at the cylindrical zone at the timber/adhesive interface. Increased bonded lengths resulted in corresponding decrease in interfacial bond stress. At 250 mm bonded length, the pull-out capacity of the proposed design model was about 2% lower than that of the tests. The results also showed that the bond stress of the theoretical model (at the ascending and descending branches) of the stress–slip curve was approximately 5–10% of that of the experiment.

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Abstract Objective To determine if high umbilical artery Doppler (UAD) pulsatility index (PI) is associated with cardio-vascular (CV) risk-factors in children at age 12 years. Methods We studied 195 children at age 12 years who had had in-utero UAD studies performed at 28 weeks gestation. The children were grouped according to whether their umbilical Doppler PI was high (indicating poor feto-placental circulation) or normal. At age 12 years we assessed CV risk factors, including anthropometric measures, blood pressure, pulse wave velocity (a measure of arterial compliance), cardio-respiratory fitness and homocysteine and cholesterol serum levels. Results Compared with children with a normal UAD PI (N=88), the children (N=107) with high UAD PI had higher resting pulse rate (p=0.04), higher pulse wave velocity (p=0.046), higher serum homocysteine levels (p=0.032) and reduced arterial compliance (7.58 v 8.50 m/sec, p=0.029) using univariate analysis. These differences were not present when adjusting for cofounders was modelled. Conclusion High PI on UAD testing in-utero may be associated with increased likelihood of some cardio-vascular risk factors at age 12-years but confounding variables may be as important. Our study raises possible long-term benefits of in-utero UAD measurements.

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Pretensioned concrete members are designed and manufactured by using at least two materials: concrete and prestressing reinforcement. Also, two main stages must be considered: prestress transfer and member loading. Hence, the behavior of these members depends strongly on the reinforcement-to-concrete bond performance and prestress losses. In this paper, a testing technique to measure the specific parameters related with the involved phenomena is presented. The testing technique is based on the analysis of series of specimens varying in embedment length to simulate several cross sections at only one end of a pretensioned concrete member. Each specimen is characterized by means of the sequential release of the prestress transfer (detensioning) and the pull-out (loading) operation. The test provides data on prestressing force, transmission length (initial and long-term), anchorage length (without and with slip), reinforcement slips, bond stresses, longitudinal concrete strains, concrete modulus of elasticity, and prestress losses (instantaneous and time-dependent).

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This paper investigates the pull-out behaviour (particularly the bearing resistance) of a steel grid reinforcement embedded in silty sand using laboratory tests and numerical analyses. It is demonstrated that the various common analytical equations for calculating the bearing component of pull-out resistance give a wide range of calculated values, up to about 200% disparity. The disparity will increase further if the issue of whether to use the peak or critical state friction angle is brought in. Furthermore, these equations suggest that the bearing resistance factor, N, is only a function of soil friction angle which is not consistent with some design guidelines. In this investigation, a series of large scale laboratory pull-out tests under different test pressures were conducted. The test results unambiguously confirmed that the N factor is a function of test pressure. A modified equation for calculating N is also proposed. To have more in-depth understanding of the pull-out behaviour, the tests were modelled numerically. The input parameters for the numerical analysis were obtained from laboratory triaxial tests. The analysis results were compared with the experimental results. Good agreement between experimental and numerical results was achieved if the strain-softening behaviour from peak strength to critical state condition was captured by the soil model used. © 2013 Elsevier Ltd.

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Implementation of both design for durability and performance-based standards and specifications are limited by the lack of rapid, simple, science-based test methods for characterizing the transport properties and deterioration resistance of concrete. To this end, this paper presents the background rationale and current developments in the application of electrical property measurements - conductivity in this instance - as a testing methodology to evaluate the relative performance of a range of concrete mixes. The technique can not only be used on standard specimens (e.g. cubes), but also lends itself to in-situ monitoring thereby allowing measurements to be obtained on the as-placed concrete. It is the latter which forms the focus of the current work. Conductivity measurements are presented for concretes with and without supplementary cementitious materials (SCM's) from demoulding up to 400-days. It is shown that electrical conductivity measurements display a continual decrease over the entire test period and attributed to the pore structure refinement due to hydration and pozzolanic reaction in those concretes containing blast furnace slag or fly ash. The term Formation Factor is introduced to rank concrete performance in terms of is resistance to chloride penetration.

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There is interest in determining levels of Mycobacterium avium subsp. paratuberculosis (MAP) contamination in milk. The optimal sample preparation for raw cows' milk to ensure accurate enumeration of viable MAP by the peptide-mediated magnetic separation (PMS)-phage assay was determined. Results indicated that milk samples should be refrigerated at 4 C after collection and MAP testing should commence within 24 h, or samples can be frozen at 70 C for up to one month without loss of MAP viability. Use of Bronopol is not advised as MAP viability is affected. The vast majority (>95%) of MAP in raw milk sedimented to the pellet upon centrifugation at 2500 g for 15 min, so this milk fraction should be tested. De-clumping of MAP cells was most effectively achieved by ultrasonication of the resuspended milk pellet on ice in a sonicator bath at 37 kHz for 4 min in ‘Pulse’ mode.

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Recent research has shown that higher ambient turbulence leads to better wake recovery, so turbines could be installed in closer proximity in real tidal flows than might be assumed from typical towing tank tests that do not take into account turbulent inflow conditions. The standard tools to assess flow velocities in field conditions are Doppler based sonar devices, such as Acoustic Doppler Profilers (ADPs) or Acoustic Doppler Velocimeters (ADVs). The use of these devices poses some challenges when assessing the wake of a tidal turbine. While ADPs allow the three-dimensional measurement of a velocity profile over a distance, the data is calculated as a mean of three diverging beams and with low temporal resolution. ADVs can measure with higher sampling frequency but only at a single point in the flow. During the MaRINET testing of the SCHOTTELSIT turbine at the QUB tidal test site in Portaferry, Northern Ireland, ADP and ADV measurements were successfully tested.Two methods were employed for measuring the wake: firstly, with a rigidly mounted ADP and secondly, with a submerged ADV which was streamed behind the turbine. This paper presents the experimental set-up and results and discusses limitations and challenges of the two methods used.

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Background: Prospective investigations of the association between impaired orthostatic blood pressure (BP) regulation and cognitive decline in older adults are limited, and findings to-date have been mixed. The aim of this study was to determine whether impaired recovery of orthostatic BP was associated with change in cognitive function over a 2-year period, in a population based sample of community dwelling older adults. 

Methods: Data from the first two waves of the Irish Longitudinal Study on Ageing were analysed. Orthostatic BP was measured during a lying to standing orthostatic stress protocol at wave 1 using beat-to-beat digital plethysmography, and impaired recovery of BP at 40 s post stand was investigated. Cognitive function was assessed at wave 1 and wave 2 (2 years later) using the Mini-Mental State Exam (MMSE), verbal fluency and word recall tasks. 

Results: After adjustment for measured, potential confounders, and multiple imputation for missing data, the change in the number of errors between waves on the MMSE was 10 % higher [IRR (95 % CI) = 1.10 (0.96, 1.26)] in those with impaired recovery at 40 s. However, this was not statistically significant (p = 0.17). Impaired BP recovery was not associated with change in performance on any of the other cognitive measures. 

Conclusions: There was no clear evidence for an association between impaired recovery of orthostatic BP and change in cognition over a 2-year period in this nationally representative cohort of older adults. Longer follow-up and more detailed cognitive testing would be advantageous to further investigate the relationship between orthostatic BP and cognitive decline.

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Background: We aimed to test whether the three classical hypotheses of the interaction between posttraumatic symptomatology and substance use (high risk of trauma exposure, susceptibility for posttraumatic symptomatology, and self-medication of symptoms), may be useful in the understanding of substance use among burn patients. Methods: We analysed substance use data (nicotine, alcohol, cannabis, amphetamines, cocaine, opiates, and tranquilizers) and psychopathology measures among burn patients admitted to a Burns Unit and enrolled in a longitudinal observational study. Lifetime substance use information (n = 246) was incorporated to analyses aiming to test the high risk hypothesis. Only patients assessed for psychopathology in a six months follow-up (n = 183) were included in prospective analyses testing the susceptibility and self-medication hypotheses. Results: Regarding the high risk hypothesis, results show a higher proportion of heroin and tranquilizer users compared to the general population. Furthermore, in line with the susceptibility hypothesis, higher levels of symptomatology were found in lifetime alcohol, tobacco and drug users during recovery. The self-medication hypothesis could be tested partially due to the hospital stay “cleaning” effect, but severity of symptoms was linked to caffeine, nicotine, alcohol and cannabis use after discharge. Conclusions: We found that the three classical hypotheses could be used to understand the link between traumatic experiences and substance use explaining different patterns of burn patient’s risk for trauma exposure and emergence of symptomatology.

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PURPOSE: We report on the in vivo testing of a novel noninvasively adjustable glaucoma drainage device (AGDD), which features an adjustable outflow resistance, and assess the safety and efficiency of this implant. METHODS: Under general anesthesia, the AGDD was implanted on seven white New Zealand rabbits for a duration of 4 months under a scleral flap in a way analogous to the Ex-PRESS device and set in an operationally closed position. The IOP was measured on a regular basis on the operated and control eyes using a rebound tonometer. Once a month the AGDD was adjusted noninvasively from its fully closed to its fully open position and the resulting pressure drop was measured. The contralateral eye was not operated and served as control. After euthanization, the eyes were collected for histology evaluation. RESULTS: The mean preoperative IOP was 11.1 ± 2.4 mm Hg. The IOP was significantly lower for the operated eye (6.8 ± 2 mm Hg) compared to the nonoperated eye (13.1 ± 1.6 mm Hg) during the first 8 days after surgery. When opening the AGDD from its fully closed to fully open position, the IOP dropped significantly from 11.2 ± 2.9 to 4.8 ± 0.9 mm Hg (P < 0.05). CONCLUSIONS: Implanting the AGDD is a safe and uncomplicated surgical procedure. The fluidic resistance was noninvasively adjustable during the postoperative period with the AGDD between its fully closed and fully open positions.