921 resultados para Immediate loading
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Rectangular hollow section (RHS) members are components widely used in engineering applications because of their good-looking, good properties in engineering areas and inexpensive cost comparing to members with other sections. The increasing use of RHS in load bearing structures makes it necessary to analyze the fatigue behavior of the RHS members. In this thesis, concentration will be given to the fatigue behavior of the RHS members under variable amplitude pure torsional loading. For the RHS members, failure will normally occur in the corner region if the welded regions are under full penetration. This is because of the complicated stress components' distributions at the RHScorners, where all of three fracture mechanics modes will happen. Mode I is mainly caused by the residual stresses that caused by the manufacturing process. Modes II and III are caused by the applied torsional loading. Stress based Findleymodel is also used to analyze the stress components. Constant amplitude fatigue tests have been done as well as variable amplitude fatigue tests. The specimens under variable amplitude loading gave longer fatigue lives than those under constant amplitude loading. Results from tests show an S-N curvewith slope around 5.
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Background: To evaluate the safety of immediate sequential bilateral cataract extraction (ISBCE) with respect to indications, visual outcomes, complications, benefits and disadvantages. Methods: This is a retrospective review of all ISBCEs performed at Kantonsspital Winterthur, Switzerland, between April 2000 and September 2013. The case notes of 500 eyes of 250 patients were reviewed. Of these 500 eyes, 472 (94.4%) had a straight forward phacoemulsification with posterior chamber intraocular lens implantation; 21 (4.2%) had a planned extracapsular cataract extraction; 4 (0.8%) had an intracapsular cataract extraction and 3 (0.6%) had a combined phacoemulsification with trabeculectomy. Results: Over 66% of eyes achieved improved visual acuity (at least 3 Snellen lines) following ISBCE. Median preoperative best corrected visual acuity (BCVA) was 0.5 LogMAR; the interquartile range was [0.4, 1] LogMAR. At one week control the median BCVA was 0.3 LogMAR, IQR [0.1, 0.5] LogMAR. At one month the median BCVA was 0.15 LogMAR, IQR [0.05, 0.3] (p < 0.01). There were no sight-threatening intraoperative or postoperative complications observed. Conclusions: ISBCE is an effective and safe option with high degree of patient satisfaction. The relative benefits of ISBCE should be balanced against the theoretically enhanced risks.
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Abstract Background: To evaluate the predictability of refraction following immediate sequential bilateral cataract surgery (ISBCS) performed under general anaesthesia. Methods: This is a retrospective review of all ISBCS performed at Kantonsspital Winterthur, Switzerland, between April 2000 and September 2013. The case notes of 250 patients were reviewed. Patients having full refraction reported (110 patients/220 eyes) were included. 210 (95 %) eyes had a straight forward phacoemulsification with posterior chamber intraocular lens implantation, seven eyes had a planned extracapsular cataract extraction (ECCE); three eyes had an intracapsular cataract extraction. Results: Both eyes of 110 patients (64 women, 46 men) with a mean age of 79.0 years, standard deviation (SD) ±11.4 (range 26 to 97 years) were included. Median preoperative best corrected visual acuity (BCVA) was 0.5 LogMAR in the first eye, the interquartile range (IQR) was [0.4, 1.2]; 0.7 LogMAR in the second eye with IQR [0.4, 1.8]. At one month, the median BCVA was 0.2 LogMAR, IQR [0.1, 0.3] in the first eye, median BCVA was 0.1 LogMAR and IQR [0.0, 0.5] in the second eye. There were 3 eyes (3 %) that lost 3 lines or more in BCVA at one month (control vs. pre-operatively). In all three cases, poor visual acuity had been recorded pre-operatively (>1 LogMAR). Achieved refraction was within ±1.0 D of the target in 83 % of eyes. There were only 5 % (n = 6) of cases where if delayed sequential bilateral extraction had been performed could potentially intraocular lens (IOL) choice have been adjusted, in four of these cases, target refraction was within ±1.0 D in the second eye. Conclusions: ISBCS performed under general anaesthesia achieves target refraction in 83 % of eyes after consideration of complications, ocular co-morbidities and systemic restrictions. In the majority of cases where IOL power calculation could be considered, the achieved refraction of the second surgical eye was within ±1.0 D of intended refraction. This undermines the utility of IOL power adjustments in the second surgical eye. Keywords: Cataract, Cataract surgery, Immediate sequential bilateral cataract surgery
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The thesis discusses games and the gaming experience. It is divided into two main sections; the first examines games in general, while the second concentrates exclusively on electronic games. The text approaches games from two distinct directions by looking at both their spatiality and their narrativity at the same time. These two points of view are combined right from the beginning of the text as they are used in conceptualising the nature of the gaming experience. The purpose of the thesis is to investigate two closely related issues concerning both the field of game studies and the nature of games. In regard to studying games, the focus is placed on the juxtaposition of ludology and narratology, which acts as a framework for looking at gaming. In addition to aiming to find out whether or not it is possible to undermine the said state of affairs through the spatiality of games, the text looks at the interrelationships of games and their spaces as well as the role of narratives in those spaces. The thesis is characterised by discussing alternative points of view and its hypothetical nature. During the text, it becomes apparent that the relationship between games and narratives is strongly twofold: on one hand, the player continuously narrativizes the states the game is in while playing, while the narratives residing within the game space form their own partially separate narrative spaces, on the other. These spaces affect the conception the player has of the game states and the events taking place in the game space itself.
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Partial-thickness tears of the supraspinatus tendon frequently occur at its insertion on the greater tubercule of the humerus, causing pain and reduced strength and range of motion. The goal of this work was to quantify the loss of loading capacity due to tendon tears at the insertion area. A finite element model of the supraspinatus tendon was developed using in vivo magnetic resonance images data. The tendon was represented by an anisotropic hyperelastic constitutive law identified with experimental measurements. A failure criterion was proposed and calibrated with experimental data. A partial-thickness tear was gradually increased, starting from the deep articular-sided fibres. For different values of tendon tear thickness, the tendon was mechanically loaded up to failure. The numerical model predicted a loss in loading capacity of the tendon as the tear thickness progressed. Tendon failure was more likely when the tendon tear exceeded 20%. The predictions of the model were consistent with experimental studies. Partial-thickness tears below 40% tear are sufficiently stable to persist physiotherapeutic exercises. Above 60% tear surgery should be considered to restore shoulder strength.
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OBJECTIVES: The aim of this study was to assess the safety of the concurrent administration of a clopidogrel and prasugrel loading dose in patients undergoing primary percutaneous coronary intervention. BACKGROUND: Prasugrel is one of the preferred P2Y12 platelet receptor antagonists for ST-segment elevation myocardial infarction patients. The use of prasugrel was evaluated clinically in clopidogrel-naive patients. METHODS: Between September 2009 and October 2012, a total of 2,023 STEMI patients were enrolled in the COMFORTABLE (Comparison of Biomatrix Versus Gazelle in ST-Elevation Myocardial Infarction [STEMI]) and the SPUM-ACS (Inflammation and Acute Coronary Syndromes) studies. Patients receiving a prasugrel loading dose were divided into 2 groups: 1) clopidogrel and a subsequent prasugrel loading dose; and 2) a prasugrel loading dose. The primary safety endpoint was Bleeding Academic Research Consortium types 3 to 5 bleeding in hospital at 30 days. RESULTS: Of 2,023 patients undergoing primary percutaneous coronary intervention, 427 (21.1%) received clopidogrel and a subsequent prasugrel loading dose, 447 (22.1%) received a prasugrel loading dose alone, and the remaining received clopidogrel only. At 30 days, the primary safety endpoint was observed in 1.9% of those receiving clopidogrel and a subsequent prasugrel loading dose and 3.4% of those receiving a prasugrel loading dose alone (adjusted hazard ratio [HR]: 0.57; 95% confidence interval [CI]: 0.25 to 1.30, p = 0.18). The HAS-BLED (hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile international normalized ratio, elderly, drugs/alcohol concomitantly) bleeding score tended to be higher in prasugrel-treated patients (p = 0.076). The primary safety endpoint results, however, remained unchanged after adjustment for these differences (clopidogrel and a subsequent prasugrel loading dose vs. prasugrel only; HR: 0.54 [95% CI: 0.23 to 1.27], p = 0.16). No differences in the composite of cardiac death, myocardial infarction, or stroke were observed at 30 days (adjusted HR: 0.66, 95% CI: 0.27 to 1.62, p = 0.36). CONCLUSIONS: This observational, nonrandomized study of ST-segment elevation myocardial infarction patients suggests that the administration of a loading dose of prasugrel in patients pre-treated with a loading dose of clopidogrel is not associated with an excess of major bleeding events. (Comparison of Biomatrix Versus Gazelle in ST-Elevation Myocardial Infarction [STEMI] [COMFORTABLE]; NCT00962416; and Inflammation and Acute Coronary Syndromes [SPUM-ACS]; NCT01000701).
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Automated Fiber Placement is being extensively used in the production of major composite components for the aircraft industry. This technology enables the production of tow-steered panels, which have been proven to greatly improve the structural efficiency of composites by means of in-plane stiffness variation and load redistribution. However, traditional straight-fiber architectures are still preferred. One of the reasons behind this is related to the uncertainties, as a result of process-induced defects, in the mechanical performance of the laminates. This experimental work investigates the effect of the fiber angle discontinuities between different tow courses in a ply on the un-notched and open-hole tensile strength of the laminate. The influence of several manufacturing parameters are studied in detail. The results reveal that 'ply staggering' and '0% gap coverage' is an effective combination in reducing the influence of defects in these laminates
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Marine environments are frequently exposed to oil spills as a result of transportation, oil drilling or fuel usage. Whereas large oil spills and their effects have been widely documented, more common and recurrent small spills typically escape attention. To fill this important gap in the assessment of oil-spill effects, we performed two independent supervised full sea releases of 5 m(3) of crude oil, complemented by on-board mesocosm studies and sampling of accidentally encountered slicks. Using rapid on-board biological assays, we detect high bioavailability and toxicity of dissolved and dispersed oil within 24 h after the spills, occurring fairly deep (8 m) below the slicks. Selective decline of marine plankton is observed, equally relevant for early stages of larger spills. Our results demonstrate that, contrary to common thinking, even small spills have immediate adverse biological effects and their recurrent nature is likely to affect marine ecosystem functioning.
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Porous silicon (PSi) is a promising material to be utilized in drug delivery formulations. The release rate of the drug compound can be controlled by changing the pore properties and surface chemistry of PSi. The loading of a poorly soluble drug into mesoporous silicon particles enhances its dissolution in the body. The drug loading is based on adsorption. The attainable maximum loaded amount depends on the properties of the drug compound and the PSi material, and on the process conditions. The loading solvent also essentially affects the adsorption process. The loading of indomethacin into PSi particles with varying surface modification was studied. Solvent mixtures were applied in the loading, and the loaded samples were analyzed with thermal analysis methods. The best degree of loading was obtained using a mixture of dichloromethane and methanol. The drug loads varied from 7.7 w-% to 26.8 w-%. A disturbing factor in the loading experiments was the tendency of indomethacin to form solvates with the solvents applied. In addition, the physical form and stability of indomethacin loaded in PSi and silica particles were studied using Raman spectroscopy. In the case of silica, the presence of crystalline drug as well as the polymorph form can be detected, but the method proved to be not applicable for PSi particles.
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Arkit: 1 arkintunnukseton lehti, D3 D4 E3.
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Arkit: 1 arkintunnukseton lehti, C-D2.
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A series of Group VIII metal catalysts was obtained for the semi-hydrogenation of styrene. Catalysts were characterized by Hydrogen Chemisorption, TPR and XPS. Palladium, rhodium and platinum low metal loading prepared catalysts presented high activity and selectivity (ca. 98%) during the semi-hydrogenation of styrene, being palladium the most active catalyst. The ruthenium catalyst also presented high selectivity (ca. 98%), but the lowest activity. For the palladium catalyst, the influence of the precursor salt and of the reduction temperature on the activity and selectivity were studied. The following activity series was obtained: PdN-423 > PdCl-673 > PdCl-373> PtCl-673 > RhCl-673 >> RuCl-673. As determined by XPS, differences in activity could be attributed, at least in part, to electronic effects.
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Arkit: 1 arkintunnukseton lehti, A-B4.
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This work describes the development and validation of a dissolution test for 60 mg of diltiazem hydrochloride in immediate release capsules. The best dissolution in vitro profile was achieved using potassium phosphate buffer at pH 6.8 as the dissolution medium and paddle as the apparatus at 50 rpm. The drug concentrations in the dissolution media were determined by UV spectrophotometry and HPLC and a statistical analysis revealed that there were significant differences between HPLC and spectrophotometry. This study illustrates the importance of an official method for the dissolution test, since there is no official monograph for diltiazem hydrochloride in capsules.