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Certain Situations (certain + situation)
Selected AbstractsFretting fatigue behaviour of shot-peened Ti-6Al-4V at room and elevated temperaturesFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 9 2003H. LEE ABSTRACT Fretting fatigue behaviour of shot-peened titanium alloy, Ti-6Al-4V was investigated at room and elevated temperatures. Constant amplitude fretting fatigue tests were conducted over a wide range of maximum stresses, ,max= 333 to 666 MPa with a stress ratio of R= 0.1. Two infrared heaters, placed at the front and back of specimen, were used to heat and maintain temperature of the gage section of specimen at 260 °C. Residual stress measurements by X-ray diffraction method before and after fretting test showed that residual compressive stress was relaxed during fretting fatigue. Elevated temperature induced more residual stress relaxation, which, in turn, decreased fretting fatigue life significantly at 260 °C. Finite element analysis (FEA) showed that the longitudinal tensile stress, ,xx varied with the depth inside the specimen from contact surface during fretting fatigue and the largest ,xx could exist away from the contact surface in a certain situation. A critical plane based fatigue crack initiation model, modified shear stress range parameter (MSSR), was computed from FEA results to characterize fretting fatigue crack initiation behaviour. It showed that stress relaxation during test affected fretting fatigue life and location of crack initiation significantly. MSSR parameter also predicted crack initiation location, which matched with experimental observations and the number of cycles for crack initiation, which showed the appropriate trend with the experimental observations at both temperatures. [source] A Test of Alternative Measures of Disconfirmation,DECISION SCIENCES, Issue 1 2003Richard A. Spreng ABSTRACT Disconfirmation has been widely used in a number of research traditions, however there are many different operationalizations of this construct. Little research has investigated the relative effectiveness of these various methods. The research reported here examines five operationalizations of disconfirmation and their effect on satisfaction. These tests are carried out using two different comparison standards in two different settings. The results indicate some methods are better in certain situations and are inappropriate in others. Implications for both practical and theoretical research are discussed. [source] Combined therapy in the treatment of hypertensionFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 1 2010Carlos Escobar Abstract The majority of patients with hypertension need at least two antihypertensive agents to achieve blood pressure (BP) objectives. As current European guidelines for the treatment of arterial hypertension recommend, combined therapy is required when monotherapy fails and as a first-line treatment in certain situations, such as subjects at high or very high cardiovascular risk, markedly elevated BP values, or when lower targets are required (<130/80 mmHg). The advantages of combined therapy are well known and include an earlier and higher antihypertensive efficacy because of complementary mechanisms of action, and a lower incidence of side effects due to the possible compensatory responses and, in many cases, the lower doses used. In the present study, available evidence about the efficacy and tolerability of combined therapy for the treatment of hypertension is updated. [source] Improved association analyses of disease subtypes in case-parent triadsGENETIC EPIDEMIOLOGY, Issue 3 2006Michael P. Epstein Abstract The sampling of case-parent triads is an appealing strategy for conducting association analyses of complex diseases. In certain situations, one may have interest in using the triads to identify genetic variants that are associated with a specific subtype of disease, perhaps related to a characteristic cluster of symptoms. A straightforward strategy for conducting such a subtype analysis would be to analyze only those triads with the subtype of interest. While such a strategy is valid, we show that triads without the subtype of interest can provide additional genetic information that increases power to detect association with the subtype of interest. We incorporate this additional information using a likelihood-based framework that permits flexible modeling and estimation of allelic effects on disease subtypes and also allows for missing parental data. Using simulated data under a variety of genetic models, we show that our proposed association test consistently outperforms association tests that only analyze triads with the subtype of interest. We also apply our method to a triad study of attention-deficit hyperactivity disorder and identify a genetic variant in the dopamine transporter gene that is associated with a subtype characterized by extreme levels of both inattentive and hyperactive-impulsive symptoms. Genet. Epidemiol. 2006. © 2006 Wiley-Liss, Inc. [source] Altered immune response to CNS viral infection in mice with a conditional knock-down of macrophage-lineage cellsGLIA, Issue 2 2006Jessica Carmen Abstract Neuroadapted Sindbis Virus (NSV) is a neuronotropic virus that causes hindlimb paralysis in susceptible mice and rats. The authors and others have demonstrated that though death of infected motor neurons occurs, bystander death of uninfected neurons also occurs and both contribute to the paralysis that ensues following infection. The authors have previously shown that the treatment of NSV-infected mice with minocycline, an inhibitor that has many functions within the central nervous system (CNS), including inhibiting microglial activation, protects mice from paralysis and death. The authors, therefore, proposed that microglial activation may contribute to bystander death of motor neurons following NSV infection. Here, the authors tested the hypothesis using a conditional knock-out of activated macrophage-lineage cells, including endogenous CNS macrophage cells. Surprisingly, ablation of these cells resulted in more rapid death and similar weakness in the hind limbs of NSV-infected animals compared with that of control animals. Several key chemokines including IL-12 and monocyte chemoattractant protein-1 (MCP-1) did not become elevated in these animals, resulting in decreased infiltration of T lymphocytes into the CNS of the knock-down animals. Either because of the decreased macrophage activation directly or because of the reduced immune cell influx, viral replication persisted longer within the nervous system in knock-down mice than in wild type mice. The authors, therefore, conclude that although macrophage-lineage cells in the CNS may contribute to neurodegeneration in certain situations, they also serve a protective role, such as control of viral replication. © 2006 Wiley-Liss, Inc. [source] Are House Wren Troglodytes aedon eggs unusually strong?IBIS, Issue 2 2002Test of the predicted effect of intraspecific egg destruction As a result of opposing selective forces, the external strength of avian eggs should be near some size-specific optimum. However, in certain situations there should be selection on females to lay unusually strong eggs. According to one hypothesis, intraspecific egg destruction should favour increased egg strength as a means of defence against conspecific intruders. This hypothesis predicts that House Wrens Troglodytes aedon, a species well known for its tendency to destroy conspecific clutches, should be under selection for unusually strong eggs. However, the intensity of selection for strong eggs should also be modified by efficacy of nest defence against conspecific intruders in a given species (i.e. efficient nest defence by the breeding pair should weaken selection for unusually strong eggs). The goals of our study were: (1) to establish whether House Wren eggs are stronger than expected for their size; (2) to determine which structural mechanisms are responsible for their unusual strength; and (3) to test a hypothesis that, between wren species, the efficacy of nest defence and the intensity of egg-destroying behaviour affect the intensity of selection for unusually strong eggs. Our results demonstrated that: (1) House Wren eggs are 1.9 times stronger than expected for their size; (2) their unusual strength is achieved mostly by their unusually thick shells; and (3) eggs of the House Wren (extensive paternal nest defence; male egg-destroying behaviour suppressed during incubation) are significantly weaker structurally than eggs of the Marsh Wren Cistothorus palustris (reduced paternal nest defence; male egg-destroying behaviour present throughout incubation). These results are consistent with the hypothesis that the intraspecific egg-destroying behaviour and the efficacy of nest defence by the breeding adults have played a role in the evolution of strength of House Wren eggs. [source] Safety and risk of using pediatric donor livers in adult liver transplantationLIVER TRANSPLANTATION, Issue 1 2001Sukru Emre MD Pediatric donor (PD) livers have been allocated to adult transplant recipients in certain situations despite size discrepancies. We compared data on adults (age , 19 years) who underwent primary liver transplantation using livers from either PDs (age < 13 years; n = 70) or adult donors (ADs; age , 19 years; n = 1,051). We also investigated the risk factors and effect of prolonged cholestasis on survival in the PD group. In an attempt to determine the minimal graft volume requirement, we divided the PD group into 2 subgroups based on the ratio of donor liver weight (DLW) to estimated recipient liver weight (ERLW) at 2 different cutoff values: less than 0.4 (n = 5) versus 0.4 or greater (n = 56) and less than 0.5 (n = 21) versus 0.5 or greater (n = 40). The incidence of hepatic artery thrombosis (HAT) was significantly greater in the PD group (12.9%) compared with the AD group (3.8%; P = .0003). Multivariate analysis showed that preoperative prothrombin time of 16 seconds or greater (relative risk, 3.206; P = .0115) and absence of FK506 use as a primary immunosuppressant (relative risk, 4.477; P = .0078) were independent risk factors affecting 1-year graft survival in the PD group. In the PD group, transplant recipients who developed cholestasis (total bilirubin level , 5 mg/dL on postoperative day 7) had longer warm (WITs) and cold ischemic times (CITs). Transplant recipients with a DLW/ERLW less than 0.4 had a trend toward a greater incidence of HAT (40%; P < .06), septicemia (60%), and decreased 1- and 5-year graft survival rates (40% and 20%; P = .08 and .07 v DLW/ERLW of 0.4 or greater, respectively). In conclusion, the use of PD livers for adult recipients was associated with a greater risk for developing HAT. The outcome of small-for-size grafts is more likely to be adversely affected by longer WITs and CITs. The safe limit of graft volume appeared to be a DLW/ERLW of 0.4 or greater. [source] Iatrogenic complications and risks of nerve conduction studies and needle electromyographyMUSCLE AND NERVE, Issue 5 2003Amer Al-Shekhlee MD Abstract Electrodiagnostic procedures are routinely performed in patients with a variety of neuromuscular disorders. These studies are generally well tolerated and rarely thought to be associated with any significant side effects. However, needle electromyography is an invasive procedure and under certain situations has the potential to be associated with iatrogenic complications, including bleeding, infection, nerve injury, pneumothorax, and other local trauma. Similar complications are possible if needles are used for either stimulating or recording. In addition, like all other electrical devices and monitoring equipment connected to patients, electrodiagnostic testing carries the risk of stray leakage currents that under certain circumstances can result in electrical injury, especially in patients in the intensive care setting. Similarly, certain precautions are required during nerve conduction studies (NCS) in patients with pacemakers and other similar cardiac devices. In this review, we address the known and theoretical complications of NCS and needle electrode examination, and the possible methods to avoid such hazards. Muscle Nerve 27: 517,526, 2003 [source] Comparing data mining methods on the VAERS database,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 9 2005David Banks PhD Abstract Purpose Data mining may enhance traditional surveillance of vaccine adverse events by identifying events that are reported more commonly after administering one vaccine than other vaccines. Data mining methods find signals as the proportion of times a condition or group of conditions is reported soon after the administration of a vaccine; thus it is a relative proportion compared across vaccines, and not an absolute rate for the condition. The Vaccine Adverse Event Reporting System (VAERS) contains approximately 150,000 reports of adverse events that are possibly associated with vaccine administration. Methods We studied four data mining techniques: empirical Bayes geometric mean (EBGM), lower-bound of the EBGM's 90% confidence interval (EB05), proportional reporting ratio (PRR), and screened PRR (SPRR). We applied these to the VAERS database and compared the agreement among methods and other performance properties, particularly focusing on the vaccine,event combinations with the highest numerical scores in the various methods. Results The vaccine,event combinations with the highest numerical scores varied substantially among the methods. Not all combinations representing known associations appeared in the top 100 vaccine,event pairs for all methods. Conclusions The four methods differ in their ranking of vaccine,COSTART pairs. A given method may be superior in certain situations but inferior in others. This paper examines the statistical relationships among the four estimators. Determining which method is best for public health will require additional analysis that focuses on the true alarm and false alarm rates using known vaccine,event associations. Evaluating the properties of these data mining methods will help determine the value of such methods in vaccine safety surveillance. Copyright © 2005 John Wiley & Sons, Ltd. [source] The "Three-Step Test" and the Wider Public Interest: Towards a More Inclusive InterpretationTHE JOURNAL OF WORLD INTELLECTUAL PROPERTY, Issue 6 2009Robin Wright Intellectual property law aims to protect the public interest in two often-contradictory ways: by granting exclusive rights to encourage creativity and by limiting those rights in certain situations for socially beneficial purposes. The Three-Step Test in international intellectual property treaties aims to ensure that limitations and exceptions to intellectual property rights do not inappropriately encroach upon the interests of rights holders. This article examines the interpretation of the Three-Step Test as included in the Agreement on Trade-Related Aspects of Intellectual Property Rights for copyright and patents by two World Trade Organization dispute-resolution panels and by other commentators. It looks at how these interpretations have dealt with the public policy motivations underlying limitations and exceptions to exclusive rights, and considers the ways in which the public policy intentions that underlie decisions by national legislators to adopt the limitations and exceptions to intellectual property rights can be considered in each step of the test. The conclusion reached is that the Three-Step Test contains the potential to allow both aspects of the public interest to be considered as part of an inclusive interpretation. [source] Responsibility Beyond Borders: State Responsibility for Extraterritorial Violations by Corporations of International Human Rights LawTHE MODERN LAW REVIEW, Issue 4 2007Robert McCorquodale States routinely provide support and assistance to their corporate nationals in their global trade and investment ventures. While states may not intend to allow corporate nationals to violate human rights in their extraterritorial operations, by their actions or omissions, states may facilitate, or otherwise contribute to, a situation in which such violations by a corporation occur. This article investigates the extent to which the extraterritorial activities of transnational corporations (TNCs) that violate international human rights law can give rise to home state responsibility. The analysis shows that home states of TNCs have obligations under international law in certain situations to regulate the extraterritorial activities of corporate nationals or the latter's foreign subsidiaries and can incur international responsibility where they fail to do so. [source] Anatomy of Complications Workshop: An educational strategy to improve performance in obstetricians and gynaecologistsAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 2 2003Ian Hammond Abstract Many specialist obstetricians and gynaecologists feel inadequately trained to deal with certain situations such as injury to bowel, bladder, ureter and major vessels, and value further training to prevent and manage these problems. We present the structure, objectives and rationale for a surgical skills workshop, which is an intensive practical learning experience aimed to improve the performance of obstetricians and gynaecologists. The overall objective of the workshop is improvement in the prevention and management of complications in obstetric and gynaecological surgery. Over 100 participants have completed the workshop so far. Pre-workshop preparation includes anatomical illustrations to guide reading and a training video describing surgical skills, ewe anatomy and hysterectomy in the ewe. There are four modules: anatomy includes an interactive lecture, cadaveric dissection and examination of prosections with specific learning tasks. Surgical skills involves the demonstration, practice and learning of techniques needed to deal with unexpected operative injury to bowel, bladder, ureter and major blood vessels. Live animal surgery on a ewe allows further supervised practice of the previously learned skills plus the repair of serious vascular injury. Case presentations allow each participant to present a complicated case in a facilitated group session with discussion and feedback from their peers. This session is controlled, non-threatening and a valuable interactive learning experience. Participant feedback suggests that this workshop format is useful and appears to improve the confidence, competence and performance of the participants. This workshop is presented as a template on which other educational activities can be developed. [source] Chop-Lump Tests for Vaccine TrialsBIOMETRICS, Issue 3 2009Dean Follmann Summary This article proposes new tests to compare the vaccine and placebo groups in randomized vaccine trials when a small fraction of volunteers become infected. A simple approach that is consistent with the intent-to-treat principle is to assign a score, say,W, equal to 0 for the uninfecteds and some postinfection outcome X,> 0 for the infecteds. One can then test the equality of this skewed distribution of,W,between the two groups. This burden of illness (BOI) test was introduced by Chang, Guess, and Heyse (1994,,Statistics in Medicine,13, 1807,1814). If infections are rare, the massive number of 0s in each group tends to dilute the vaccine effect and this test can have poor power, particularly if the,X's are not close to zero. Comparing,X,in just the infecteds is no longer a comparison of randomized groups and can produce misleading conclusions. Gilbert, Bosch, and Hudgens (2003,,Biometrics,59, 531,541) and Hudgens, Hoering, and Self (2003,,Statistics in Medicine,22, 2281,2298) introduced tests of the equality of,X,in a subgroup,the principal stratum of those "doomed" to be infected under either randomization assignment. This can be more powerful than the BOI approach, but requires unexaminable assumptions. We suggest new "chop-lump" Wilcoxon and,t -tests (CLW and CLT) that can be more powerful than the BOI tests in certain situations. When the number of volunteers in each group are equal, the chop-lump tests remove an equal number of zeros from both groups and then perform a test on the remaining,W's, which are mostly >0. A permutation approach provides a null distribution. We show that under local alternatives, the CLW test is always more powerful than the usual Wilcoxon test provided the true vaccine and placebo infection rates are the same. We also identify the crucial role of the "gap" between 0 and the,X's on power for the,t -tests. The chop-lump tests are compared to established tests via simulation for planned HIV and malaria vaccine trials. A reanalysis of the first phase III HIV vaccine trial is used to illustrate the method. [source] Semiparametric Estimation Exploiting Covariate Independence in Two-Phase Randomized TrialsBIOMETRICS, Issue 1 2009James Y. Dai Summary Recent results for case,control sampling suggest when the covariate distribution is constrained by gene-environment independence, semiparametric estimation exploiting such independence yields a great deal of efficiency gain. We consider the efficient estimation of the treatment,biomarker interaction in two-phase sampling nested within randomized clinical trials, incorporating the independence between a randomized treatment and the baseline markers. We develop a Newton,Raphson algorithm based on the profile likelihood to compute the semiparametric maximum likelihood estimate (SPMLE). Our algorithm accommodates both continuous phase-one outcomes and continuous phase-two biomarkers. The profile information matrix is computed explicitly via numerical differentiation. In certain situations where computing the SPMLE is slow, we propose a maximum estimated likelihood estimator (MELE), which is also capable of incorporating the covariate independence. This estimated likelihood approach uses a one-step empirical covariate distribution, thus is straightforward to maximize. It offers a closed-form variance estimate with limited increase in variance relative to the fully efficient SPMLE. Our results suggest exploiting the covariate independence in two-phase sampling increases the efficiency substantially, particularly for estimating treatment,biomarker interactions. [source] | ||||||||||||||||