bluuebunny/crossref_metadata_2025 huggingface dataset:
Endovascular Treatment of Visceral Artery Aneurysms
Authors: Carroccio Alfio , Jacobs Tikva S. , Faries Peter , Carroccio Alfio , Jacobs Tikva S. , Faries Peter , Ellozy Sharif H. , Teodorescu Victoria J. , Ting Windsor , Marin Michael L.
Published: October 2007

Visceral artery aneurysms, although uncommon, can present with life-threatening hemorrhage. The increasing use of imaging studies has allowed for earlier identification and intervention of these aneurysms, thus avoiding the high morbidity and mortality associated with rupture. The treatment options for visceral artery aneurysms range from conventional open surgical repair to minimally invasive techniques using covered stents or embolization materials. Anatomic features and patient selection determine which treatment option would result in the most durable treatment and outcome. This article reviews our experience with the endovascular treatment of visceral artery aneurysms.
Understanding prognostic benefits of exercise and antidepressant therapy for persons with depression and heart disease: the UPBEAT study — rationale, design, and methodological issues
Authors: Blumenthal James A , Sherwood Andrew , Rogers Sharon D. , Babyak Michael A. , Murali Doraiswamy P. , Watkins Lana , Hoffman Benson M. , O'Connell Cara , Johnson Julie J. , Patidar Seema M. , Waugh Robert , Hinderliter Alan
Published: October 2007

Background Depression is relatively common in patients with coronary heart disease (CHD) and is associated with worse prognosis. Recently there has been interest in evaluating the impact of treating depression on clinical outcomes. Anti-depressant medications have been shown to be safe and efficacious for many patients; exercise also may be effective for treating depression and may also improve cardiopulmonary functioning. However, methodological limitations of previous studies have raised questions about the value of exercise, and no study has compared the effects of exercise with standard anti-depressant medication in depressed cardiac patients.

Purpose UPBEAT is a randomized clinical trial (RCT) funded by NHLBI to evaluate the effects of sertraline or exercise compared to placebo on depression and biomarkers of cardiovascular risk in patients with CHD and elevated depressive symptoms.

Methods The UPBEAT study includes 200 stable CHD patients with scores on the Beck Depression Inventory (BDI) ≥9 randomized to 4 months of treatment with aerobic exercise, sertraline, or placebo. The primary outcomes include depressive symptoms determined by clinical ratings on the Hamilton Rating Scale for Depression (HAM-D) and measures of heart rate variability (HRV), baroreflex control (BRC), vascular function (i.e., flow-mediated dilation (FMD)), and measures of inflammation and platelet aggregation.

Results This article reviews the rationale and design of UPBEAT and addresses several key methodologic issues that were carefully considered in the development of this protocol: the use of a placebo control condition in depressed cardiac patients, study design, and selection of intermediate endpoints or biomarkers of cardiovascular risk.

Limitations This study is not powered to assess treatment group differences in CHD morbidity and mortality. Intermediate endpoints are not equivalent to `hard' clinical events and further studies are needed to determine the clinical significance of these biomarkers.

Conclusions The UPBEAT study is designed to assess the efficacy of exercise in treating depression in cardiac patients and evaluates the impact of treating depression on important biomarkers of cardiovascular risk. Clinical Trials 2007; 4: 548—559. http://ctj.sagepub.com
Predicting event times in clinical trials when randomization is masked and blocked
Authors: Donovan J. Mark , Elliott Michael R. , Heitjan Daniel F.
Published: October 2007

Background Timing for interim or final analysis of data in an event-based trial is often determined by the accrual of events during the study. Existing Bayesian methods may be used to predict the date of the landmark event using observed enrollment, event, and loss times when treatment arm information is masked.

Purpose For event-based trials with a blocked randomization, knowledge of blocks in which patients are enrolled can provide additional information to improve predictions versus models that only assume a known treatment allocation proportion. We therefore propose to incorporate blocking information into existing methods for prediction.

Methods We derive a latent variable (LV) extension of a mixture model used in Donovan JM, Elliott MR, Heitjan DF. Predicting Event Times in Clinical Trials When Treatment Arm is Masked. J Biopharmaceut Stat 2006; 16:343—56 to incorporate block randomization (constrained LV) for predicting the landmark event and compare this model with (a) methods where blocking information is ignored (unconstrained LV), and (b) methods assuming a single population (SP).

Results Comparison of the constrained and unconstrained LV models in our application shows that the constrained LV model has narrower prediction intervals. Simulation studies show that the constrained LV model can have better coverage probabilities for the prediction intervals than SP models if a treatment effect is present, and prediction intervals from the constrained LV model are narrower than those for the unconstrained LV model. These differences varied by block size and prediction time.

Limitations We have limited focus to the exponential model for events. Coverage for the LV models may be somewhat reduced if no treatment effect is present.

Conclusions Extra information provided by knowledge of blocking can be used to decrease prediction interval width versus the unconstrained LV model, while providing better coverage properties than the SP model if a treatment effect is present. Clinical Trials 2007; 4: 481—490. http://ctj.sagepub.com
The intermediate endpoint effect in logistic and probit regression
Authors: MacKinnon D.P. , Lockwood C.M. , Brown C.H. , Wang W. , Hoffman J.M.
Published: October 2007

Background An intermediate endpoint is hypothesized to be in the middle of the causal sequence relating an independent variable to a dependent variable. The intermediate variable is also called a surrogate or mediating variable and the corresponding effect is called the mediated, surrogate endpoint, or intermediate endpoint effect. Clinical studies are often designed to change an intermediate or surrogate endpoint and through this intermediate change influence the ultimate endpoint. In many intermediate endpoint clinical studies the dependent variable is binary, and logistic or probit regression is used.

Purpose The purpose of this study is to describe a limitation of a widely used approach to assessing intermediate endpoint effects and to propose an alternative method, based on products of coefficients, that yields more accurate results.

Methods The intermediate endpoint model for a binary outcome is described for a true binary outcome and for a dichotomization of a latent continuous outcome. Plots of true values and a simulation study are used to evaluate the different methods.

Results Distorted estimates of the intermediate endpoint effect and incorrect conclusions can result from the application of widely used methods to assess the intermediate endpoint effect. The same problem occurs for the proportion of an effect explained by an intermediate endpoint, which has been suggested as a useful measure for identifying intermediate endpoints. A solution to this problem is given based on the relationship between latent variable modeling and logistic or probit regression.

Limitations More complicated intermediate variable models are not addressed in the study, although the methods described in the article can be extended to these more complicated models.

Conclusions Researchers are encouraged to use an intermediate endpoint method based on the product of regression coefficients. A common method based on difference in coefficient methods can lead to distorted conclusions regarding the intermediate effect. Clinical Trials 2007; 4: 499—513. http://ctj.sagepub.com
Meta-analysis of longitudinal studies
Authors: Ishak K. Jack , Platt Robert W. , Joseph Lawrence , Hanley James A. , Caro J. Jaime
Published: October 2007

Background Longitudinal studies typically report estimates of the effect of a treatment or exposure at various times during the course of follow-up. Meta-analyses of these studies must account for correlations between effect estimates from the same study.

Purpose To describe and contrast alternative approaches to handling correlations inherent to longitudinal effect estimates in meta-analyses.

Methods. Linear mixed-effects models can account for correlations in a number of ways. We considered three alternatives: including study-specific random-effects, correlated time-specific random-effects or a general multivariate specification that also allows correlated within-study residuals. Data from a review of studies of the effect of deep-brain stimulation (DBS) in patients with Parkinson's disease are used to illustrate the application of these models. Results are contrasted with those from a naïve meta-analysis in which the correlations are ignored.

Results The data included 46 studies that yielded 82 estimates of the effect of DBS measured at 3, 6, 12 months or later after implantation of the stimulator. Models that accounted for correlations, particularly the full multivariate specification, provided better fit (lower AIC) and yielded slightly more precise effect estimates. This was in part due to a relatively extreme observation from a study that provided similar estimates at other times, which in the naïve approach exerts greater influence since it is treated as an independent observation.

Limitations Since the true values of the parameters are not known, it is impossible to confirm that estimates from the multivariate approach are necessarily more accurate.

Conclusion Standard meta-analytic models can be readily extended to account for correlations between effects in longitudinal studies. These models may provide better fit and possibly more precise summary effect estimates. Clinical Trials 2007; 4: 525—539. http://ctj.sagepub.com
Hormonal regulators of muscle and metabolism in aging (HORMA): design and conduct of a complex, double masked multicenter trial
Authors: Schroeder E. Todd , Castaneda-Sceppa Carmen , Ying Wang  , Binder Ellen F. , Kawakubo Miwa , Stewart Yolanda , Storer Thomas , Roubenoff Ronenn , Bhasin Shalender , Yarasheski Kevin E. , Sattler Fred R. , Azen Stanley P.
Published: October 2007

Background Older persons often lose muscle mass, strength, and physical function. This report describes the challenges of conducting a complex clinical investigation assessing the effects of anabolic hormones on body composition, physical function, and metabolism during aging.

Methods HORMA is a multicenter, randomized double masked study of 65—90-year-old community dwelling men with testosterone levels of 150—550 ng/dL and IGF-1 < 167 ng/dL. Subjects were randomized to transdermal testosterone (5 or 10 g/day) and rhGH (0, 3, or 5 μg/kg/day) for 16 weeks. Outcome measures included body composition by DEXA, MRI, and 2H2O dilution; muscle performance (strength, power, and fatigability), VO2peak, measures of physical function, synthesis/breakdown of myofibrillar proteins, other measures of metabolism, and quality of life.

Results Major challenges included delay in startup caused by need for 7 institutional contracts, creating a 142-page manual of operations, orientation and training, creating a 121-page CRF; enrollment inefficiencies; scheduling 16 evaluations/ subject; overnight admissions for invasive procedures and isotope infusions; large data and image management and transfer; quality control at multiples sites; staff turnover; and replacement of a clinical testing site. Impediments were largely solved by implementation of a web-based data entry and eligibility verification; electronic scheduling for multiple study visits; availability of research team members to educate and reassure subjects; more frequent site visits to validate all source documents and reliability of data entry; and intensifying quality control in testing and imaging. The study exceeded the target goal of 108 (n = 112) completely evaluable cases. Two interim DSMB meetings confirmed the lack of excessive adverse events, lack of center effects, comparability of subjects, and that distribution of subjects and enrollment will not jeopardize outcomes or generalizability of results.

Conclusions Flexibility and rapidly solving evolving problems is critical when conducting highly complex multicenter metabolic studies. Clinical Trials 2007; 4: 560—570. http://ctj.sagepub.com
Bias reduction with an adjustment for participants' intent to dropout of a randomized controlled clinical trial
Authors: Leon Andrew C. , Demirtas Hakan , Hedeker Donald
Published: October 2007

Background Attrition, which is virtually ubiquitous in randomized controlled clinical trials, introduces problems of increased bias and reduced statistical power. Although likelihood-based statistical models such as mixed-effects models can accommodate incomplete data, the assumption of ignorable attrition is usually required for valid inferences.

Purpose In an effort to make the ignorability assumption more plausible, we consider the value of one readily obtained covariate that has been recommended by others, asking participants to rate their Intent to Attend the next assessment session.

Methods Here we present a simulation study that compares the bias and coverage in mixed-effects outcome analyses that do and do not include Intent to Attend as a covariate.

Results For the simulation specifications that we examined, the results are promising in the sense of reduced bias and greater precision. Specifically, if the time-varying Intent to Attend variable is associated with attrition, outcome and treatment group, bias is substantially reduced by including it in the outcome analyses.

Limitations Analyses that are adjusted in this way will only yield unbiased estimates of efficacy if attrition is ignorable based on the self-rated intentions.

Conclusions Accounting for participants' Intent to Attend the next assessment session will reduce attrition bias under conditions examined here. The item adds little burden and can be used both for data analyses and to identify participants at risk of attrition. Clinical Trials 2007; 4: 540—547. http://ctj.sagepub.com
Balanced two-stage designs for phase II clinical trials
Authors: Fei Ye  , Shyr Yu
Published: October 2007

Background Oncology phase II clinical trials are often designed using Simon's two-stage designs (optimal and `minimax') for independent observations. Simon's designs do not include the use of correlated observations, and do not balance the sample sizes of the two stages. In these designs, the sample sizes of the two stages can be highly unequal. In certain circumstances, an alternative design option that balances the sample sizes is desirable.

Purpose To develop a two-stage phase II design that balances the sample sizes of the first and the second stages, while controlling for type I and type II error rates.

Methods We simulated designs based on response rates under various null and alternative hypotheses, type I and type II error constraints, and the degree of correlation in the case of correlated data. For correlated data, Sargent's method is adopted to account for the loss of information due to intra-person correlation.

Results Design characteristics for different parameter settings were generated using balanced design method, separately for independent and correlated data. Results were evaluated and compared to the optimal and minimax design.

Limitations For correlated data, designs were produced only for trials with half of the participants having one observation and the other half having two. Also, the degree of intra-person correlation was fixed at three levels.

Conclusion The balanced design provides an additional choice for two-stage phase II trials when the investigators would like to monitor the trial near a study's halfway point. Meanwhile, its total sample sizes are comparable with Simon's designs. Clinical Trials 2007; 4: 514—524. http://ctj.sagepub.com
Neighbourhood policing and community safety
Authors: Hughes Gordon , Rowe Michael
Published: October 2007

`Community' continues to be at the heart of political and policy discourses surrounding policing, security and community safety. While recognizing that there are powerful retrogressive and repressive elements to such contemporary debates, it is argued here that this is an unstable and contestable policy terrain and that there are opportunities to develop notions of community that offer more progressive possibilities. This article examines policy developments relating to Neighbourhood Policing and Crime and Disorder Reduction Partnerships in Britain to explore these issues. The latter developments emphasize that community engagement and co-production are centrally important. However, it is clear that there are dangers that already identified tensions will persist. The need to meet performance targets will continue to detract from community-oriented work, unless the two coincide. Additionally cultural and institutional factors are likely to prove inimical to efforts to respond effectively to community needs. None of this ought to be taken as an argument in favour of jettisoning the idea of community, but it does mean that the participation of publics needs to be couched in broad, inclusive and often conflictual terms and understood that such efforts offer only limited guarantees in terms of establishing progressive agendas for community safety and neighbourhood policing.
`Protean times?'
Authors: Garland Jon , Chakraborti Neil
Published: October 2007

Rural villages are often portrayed as problem-free, idyllic environments characterized by neighbourliness and cultural homogeneity. Drawing upon the growing body of research into issues of rural racism, this article challenges these prevailing notions by highlighting some of the problems associated with the increasing ethnic diversity of rural populations. The article begins by addressing the symbolic importance given to the English countryside by many of its white inhabitants, and assesses how this is related to romanticized feelings of national identity, `localism' and narrow invocations of village `communities'. It is argued that village space is not neutral but is instead racialized and contested, and that it is feelings of insecurity among white rural populations, exacerbated by the presence of a markedly different `other', that results in the marginalization of minority ethnic groups from mainstream community activities. It is also suggested that these groups are often subjected to racist victimization, which can go unrecognized by local agencies. This clearly has implications for policing diversity in the rural, and the article explores ways in which the public police (and other rural agencies) could begin to develop a more nuanced understanding of the diversification of rural space and the `othering' of outsider populations.
`Invisible minorities'
Authors: Moran Leslie J.
Published: October 2007

This article explores challenges that non-normative sexualities, in particular `lesbian' and `gay' generate for `community' and `neighbourhood' models and practices of policing. It pursues this objective by way of a series of reflections arising out of a number of encounters with lesbians and gay men, the police, policy makers and activists all of whom have been involved in an ongoing project of generating debate, building policies and changing the day-to-day operation of policing in England and Wales. These encounters occurred over a five-year period in several different geographical and institutional locations. The article concludes with a critique of two themes that connect these incidents: the use of the `minority model' lesbian and gay community and the use of `stranger danger' as the model of homophobic violence to explain that community's distinctive experience of violence.
Superplastic deformation of Ti3Al based alloy
Authors: Liu Y. Y. , Yao Z. K. , Guo H. Z. , Gao J.
Published: October 2007

Superplastic deformation behaviours of Ti3Al based alloy at high temperature have been investigated by using the non-constant strain rate electronic tensile testing apparatus. The results show that the effect of strain rate on the deformation ability of the alloy at high temperature is more significant than that of the temperature. When the alloy is deformed at lower temperature and higher strain rate, the large grain occurs necking and the small grain occurs sliding along grain boundary. Under the optimal superplastic deformation condition, the main superplastic deformation mechanism is the grain boundary sliding accompanying the dynamic recrystallisation process, which can supply the sliding and deformation sources for the deformed alloy. At higher temperature (1020°C), the superplastic deformation of the alloy consists of grain boundary sliding and the homogeneous extensions of the soft phase as well as the hard phase during the superplastic deformation.
Residual stress and thermal cycling of planar solid oxide fuel cells
Authors: Atkinson A. , Sun B.
Published: October 2007

The published literature relating to damage to planar solid oxide fuel cells caused by thermally induced stresses and thermal cycling is reviewed. This covers reported studies of thermal cycling performance and stresses induced by temperature gradients and differences in thermal expansion coefficients in typical planar SOFC configurations, namely electrolyte supported; anode supported and inert substrate supported cells. Generally good agreement is found between electrolyte residual stresses measured by X-ray diffraction or cell curvature and stresses calculated from simple thermo-elastic analysis. Finite element modelling of temperature distributions in cells and stacks in steady state operation are well advanced and capable of being extended to compute stress distributions. Failure criteria are then discussed for laminated cell structures based on critical energy release rate fracture mechanics models developed originally for coatings. However, in most cases the data required to apply the models quantitatively (such as elastic moduli of actual laminated material and fracture energies of materials and interfaces) are not available. Where data are available there are inconsistencies that require resolution. Seals are critical components in many planar solid oxide fuel cell configurations, but again there are discrepancies in experimental mechanical properties and the role of internal stresses in their fracture. In addition, there is as yet no firm evidence that thermal cycling damage involves any true materials fatigue process.
Critical study of microforging Au ball on Al coated silicon substrate using finite element method
Authors: Srikanth N.
Published: October 2007

Microforging of a gold ball on aluminium coated silicon substrate is an important process step during the interconnection of gold wires in microelectronics industry. Understanding the deformation mechanism helps to achieve the required deformed profile of the ball with maximum shear strength of the weld and minimum residual stress in the weld so as to avoid cratering of the silicon die. In the present paper, finite element based numerical modelling is well described to understand the stress and the deformation behaviour during such deformation process. In addition, experiments have been conducted to validate the numerical prediction in terms of the ball deformation. Numerical results show that maximum stress is induced at the SiO2 interface during the peak impact load application. Additionally the effect of additional ultrasonic energy during ball deformation and the growth of the intermetallics on the gold wirebond's integrity are discussed in detail.
Mechanical properties of diffusion bonded joints between titanium and stainless steel with nickel interlayer
Authors: Kundu S. , Chatterjee S.
Published: October 2007

Solid state diffusion bonded joints of commercially pure titanium and 304 stainless steel using a 300 μm nickel interlayer were prepared at 850°C for 1·8–10·2 ks under 3 MPa load in vacuum. The diffusion bonds were characterised by light and scanning electron microscopy. The SEM–BSE images show the existence of different reaction layers in the diffusion zone. The composition of these layers was determined using an electroprobe microanalyser, indicating that TiNi3, TiNi and Ti2Ni are formed at the nickel/titanium interface and the stainless steel/nickel interface is free from intermetallics. The presence of intermetallics was confirmed by the X-ray diffraction technique. Nickel can inhibit the diffusion of Ti to the stainless steel side for all bonding times. A maximum tensile strength of ∼312 MPa (∼98% of Ti) and a shear strength of ∼236 MPa (∼81% of Ti) along with ∼9·1% ductility were obtained for diffusion couple processed for 7·2 ks. Observation of fracture surfaces by SEM using EDS demonstrates that failure takes place mainly through the nickel/titanium interface.
Effect of rare earth Yb addition on mechanical properties of Al–5·3Cu–0·8Mg–0·6Ag alloy
Authors: Xiao D. H. , Song M. , Chen K. H. , Huang B. Y.
Published: October 2007

The precipitation hardening response, microstructure and mechanical properties of three Al–5·3Cu–0·8Mg–0·6Ag based alloys containing 0, 0·15 and 0·25 wt-%Yb were investigated using optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy. It is shown that increasing Yb content from 0 to 0·25 wt-% increased the tensile strength at all test temperatures up to 300 °C. The high strength of the alloys with Yb is attributed to the high density and high thermal stability of fine Ω precipitates.
Synthesis of polypropylene wrapped carbon nanotubes composite via in situ graft method with maleic anhydride
Authors: Li W. H. , Chen X. H. , Li S. N. , Xu L. S. , Yang Z.
Published: October 2007

Wrapped carbon nanotubes with polypropylene were synthesised by in situ graft method and used as a reinforcement agent for commercial polypropylene. Scanning electron microscopy and transmission electron microscopy revealed that carbon nanotubes were wrapped by polypropylene and dispersed homogeneously in polypropylene matrix. Infrared spectroscopy results showed that there was covalently linkage between polypropylene and carbon nanotubes via maleic anhydride grafting. The linkage was further confirmed by Raman observation. Furthermore, the X-ray diffraction research revealed that the carbon nanotubes act as nucleating agent to promote crystallisation. Owing to the uniform dispersion of carbon nanotubes and covalent adhesion between polypropylene and carbon nanotubes, the thermal stability of polypropylene was improved.
Hydroxyapatite nanospindles by biomimetic synthesis with chitosan as template
Authors: He D. , Xiao X. F. , Liu F. , Liu R. F.
Published: October 2007

Based on the principles of biomineralisation, spindle shaped hydroxyapatites (HA) were synthesised through the biomimetic method with chitosan (CS) as template. The microstructure, chemical composition and thermal behaviour were characterised by means of X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and thermogravimetry differential thermal analysis (TGDTA) respectively. The results show that the spindle shaped nanoHA, 30–40 nm in length and 7–8 nm in width, were synthesised with 0·5 wt-%CS as template in 6% (v/v) hydrogen peroxide solution for 7 days. The crystallinity of samples increased with the aging time. TGDTA analyses show that the HA powders synthesised with CS as template contain CS molecules and have good thermal stability up to 800°C.
Formation of intermetallic compounds with Sn–Zn–Al solder on copper and electroless nickel–immersion gold substrates
Authors: Snugovsky L. , Snugovsky P. , Perovic D. D. , Rutter J. W.
Published: October 2007

A new solder alloy, intended to replace eutectic Sn–Pb, consists of the near eutectic alloy 93 wt-%Sn plus 7 wt-%Zn, with approximately 60 ppm Al added to prevent excessive oxidation of the Zn component. On solidification, this alloy forms a broken lamellar microstructure of Zn in Sn. This paper reports a study of the interaction of this alloy with two common substrate materials, copper and electroless nickel immersion gold (ENIG). Initial contact of the liquid solder on copper for 60 s at 215-230°C formed on the copper a 2 μm thick layer of a Cu–Zn intermetallic compound. After aging for 24 h at 150°C, this compound layer thickened to approximately 3·5 μm. In addition, two layers, each containing particles of a different Cu–Zn compound replacing the Zn, formed between the interface layer and the original solder. After 150 h at 150°C, the interface layer reached 4·5 μm in thickness and the two compound containing layers a total of 65 μm. These rapid microstructural changes correspond to both Cu and Zn being rapid diffusers in solid Sn. On an ENIG substrate, contact with the liquid solder for 60 s at 230°C formed a thin (0·2 μm) and somewhat irregular reaction layer, with a composition consisting of Au, Sn and Zn. Aging for a few hours produced no appreciable change. After 265 hours at 150°C, a continuous layer 0·2 μm thick, with composition now including Ni, was formed on the ENIG interface. After 500 h at 150°C, this thin layer remained and a 10 μm thick layer denuded in Zn had developed in the adjacent solder with accompanying formation of particles having the composition 90 wt-%Zn with Ni and Au on the thin interface layer. Aging to 1150 h produced a denuded zone 17 μm thick and continued growth of the Zn-rich particles. These observed reaction rates appear to correspond to diffusion rates of the order of self-diffusion of Sn at 150°C.
Intergranular liquation cracking in heat affected zone of a welded nickel based superalloy in as cast condition
Authors: Ojo O. A.
Published: October 2007

The microstructures of the as cast and the heat affected zone (HAZ) of tungsten inert gas welded IN738 superalloy were studied. A different secondary solidification microconstituent was observed in front of some of γ– γ′ eutectic in interdendritic regions of the as cast alloy, which is likely formed by an invariant eutectic type reaction during the terminal stage of the ingot solidification. On welding, the alloy in as cast condition, suffered extensive grain boundary liquation cracking in the HAZ regions while the fusion zone was free of exclusive centerline cracking. Subsolidus liquation reactions of terminal solidification microconstituent, MC type carbides and γ′ precipitate particles present in the preweld alloy in considerable volume fraction, were observed to be major causes of HAZ intergranular liquation and the attendant cracking. Good wetting behaviour of the grain boundary liquid film possibly aided by surface active boron atoms released by the liquation of the terminal solidification reaction product is suggested as an important factor contributing to high susceptibility of the alloy to HAZ cracking in the as cast condition.
The deformation, recrystallisation and texture of three magnesium alloy extrusions
Authors: Mackenzie L. W. F. , Davis B. , Humphreys F. J. , Lorimer G. W.
Published: October 2007

The deformation, recrystallisation and texture of three magnesium alloy extrusions, AZ31, WE43 and ZC71, have been investigated. The extruded microstructures were partially recrystallised; the nucleation of new grains was associated with boundaries, deformation features and second phase particles. The unrecrystallised grains were orientated with <1010> directions parallel to the extrusion axis. In AZ31 and ZC71 the recrystallised grains also exhibited a <2110> component, which evolved into the major component during annealing. In WE43 recrystallised grains were orientated with their basal planes at ∼45° to the extrusion axis; this texture component dominated the texture following annealing. The recrystallisation grain growth textures appear to be governed by growth selection where alloying elements change the grain boundary behaviour and orientation relationships for high mobility. The tensile and compressive strengths of the extrusions were affected by the texture.
Examination of breakdown stress in creep by viscous glide in Al–5·5 at.-%Mg solid solution alloy at high stress levels
Authors: Graiss G. , El-Rehim A. F. Abd
Published: October 2007

Creep tests on Al–5·5 at.-%Mg solid solution alloy show that the stress exponent n increases with increasing stress from 3·1 to 5·5. It is demonstrated that the transition to n≈5·5 is not consistent either with normal power law breakdown or with a transition to a region of viscous glide controlled by pipe diffusion, but the results are in good agreement with a breakdown of the dislocations from their solute atmospheres. The activation energies for creep at low and high stresses are 136 and 170 kJ mol−1 respectively.
Dependence of phase composition on dry sliding behaviour in nanocomposite TiBxNy thin films
Authors: Lu Y. H. , Wang J. P. , Shen Y. G.
Published: October 2007

TiBxNy thin films with different N contents were deposited using unbalanced magnetron sputtering at room temperature. Their structure, phase composition, hardness and dry sliding behaviour were investigated by X-ray diffraction, X-ray photoelectric microscopy, microindentation, pin on disc and scanning electron microscopy. The results indicated that the phase composition in TiBxNy thin films strongly depended on N content. Nanocrystalline (nc-) TiN was preferentially formed with incorporation of N into TiB0·65 till its mole fraction reached a maximum at ∼37 at.-%N. BN was promoted to be formed with further increasing N content. Both friction coefficient and wear rate strongly depended on phase composition rather than hardness. The friction coefficient was increased with increasing N content till its maximum, accompanying with the least amount of deformed wear debris, was achieved at the mole fraction maximum of nc-TiN. A decrease in friction coefficient was followed after formation of BN, accompanying with increasing amount of deformed wear debris. The wear rate showed an inverse trend. During wear procedure, adhesive and abrasive wears coexisted and wear debris was oxidised to form the debris comprising of various types of Ti and B oxides.
Dynamic adjustment of ferrite grains during dynamic strain induced transformation
Authors: Shokouhi A. , Hodgson P. D.
Published: October 2007

The dynamic adjustment of ferrite grains formed during ‘dynamic strain induced transformation (DSIT)’ is an important feature of this mechanism that has not been addressed previously. A novel experimental method was applied to follow the effect of deformation at different stages on ferrite formed initially through DSIT. It is shown that while the continuous dynamic recrystallisation (CDRX) appears to be an acceptable mechanism for re-refinement of coarser grain size (i.e. dα>2 dDSIT), it cannot explain the steady state grain size for finer ferrite grains (i.e. dα<2 dDSIT). Other potential mechanisms involved in this phenomenon are examined.
Correlation between substrate steel texture and coating texture of two industrially produced galvanised and galvannealed steels
Authors: Chakraborty A. , Ray R. K. , Bhattacharjee D.
Published: October 2007

The substrate steel texture appears to control the texture of galvanised and galvannealed coating on steels. The ratio of the volume fraction of {113} and {111} orientations of the substrate steel may be important in controlling the texture of the overlying coating.
Effects of synthesis technology route on mechanical properties and phases/microstructures of polyurethane elastomers
Authors: Zhang H. B. , Li W. , Kong X. , Yang X. J.
Published: October 2007

In the present paper, the synthesis technology of polyurethane elastomers was studied with an aim at better controlling their phases/microstructures and properties. In particular, mechanical properties and glass transition temperatures as well as microphase separation of different polyurethane elastomers synthesised by four technology routes, with an emphasis on the effects of raw materials and their feeding sequences, were investigated using a universal testing machine, a differential scanning calorimetric (DSC) and a fourier transform infrared spectrometer (FITR). The results offered an ideal synthesis route: first diisocyanate was added into the dried polyether, then the two materials were fully reacted and finally the chain extender was added into the mixture products. The resulting polyurethane elastomer exhibited an excellent mechanical performance, a low glass transition temperature and a perfect microphase separation.
Use of brazing technique for manufacturing of high temperature fibre optical temperature and displacement transducer
Authors: Sandlin S. , Kosonen T. , Hokkanen A. , Heikinheimo L.
Published: October 2007

In contrast to the case of embedding sensing fibres in composites, very little has been published on embedding fibres in high melting point metallic alloys. In the present work a methodology is presented for manufacturing a fibre optical displacement transducer for high temperature applications. The transducer is based on in fibre Bragg gratings that are metal embedded in a transducer body made of Inconel 600 (a refractory alloy). The fibre embedding is carried out by vacuum brazing at a temperature of 900°C using a silver based brazing alloy. This technique solves many problems in constructing the transducer. During the brazing process the brazing alloy fuses with the metallic coating on the fibre. Because of this and as a consequence of the low thermal expansion of the silica the fibre will end up in axial and radial compression when the alloy around the fibre solidifies and cools down. In the present work cross-sections of embedded fibres are presented and the distribution of elements and phases in the joint is investigated in order to identify the reactions between the brazing alloy and the Ni coating on the optical fibre. Finally, the performance of the joint is illustrated by presenting some in situ optical measurement of Bragg wavelength shifts of the embedded in fibre Bragg gratings. The stress state in a two embedded fibre gratings is also estimated from the measured wavelength shifts.
Treatment and prevention of pain due to vaso-occlusive crises in adults with sickle cell disease: an educational void
Authors: Solomon Lawrence R.
Published: October 2007

Pain due to vaso-occlusive crisis is the major cause of hospital use in sickle cell disease. Although available guidelines provide recommendations for opioid administration in this setting, only 4 (21%) of 19 medical textbooks present treatment regimens that are consistent with them. Moreover, only 7 texts (37%) note that addiction is infrequent in this population, while 11 (92%) of 12 texts provide such reassurance for cancer-related pain (P < .005). Finally, hydroxyurea use to decrease the frequency of vaso-occlusive crises is completely defined only in 2 textbooks. Thus, most medical texts provide neither adequate information for the treatment or prevention of pain due to vaso-occlusive crisis in sickle cell disease nor reassurance of the unlikelihood of addiction in this population. In contrast, treatment recommendations for less common hematologic disorders are consistent with current standards in 53% to 84% of appropriate texts (P < .05). Limited knowledge regarding the principles and appropriateness of opioid therapy; a lack of evidence-based research on pain control; and misconceptions and prejudices about drug abuse and addiction contribute to this educational void. Thus, research and training on pain control in sickle cell disease are needed to parallel studies of environmental and genetic factors contributing to the known clinical heterogeneity of this disorder.
t(6;14)(p22;q32): a new recurrent IGH@ translocation involving ID4 in B-cell precursor acute lymphoblastic leukemia (BCP-ALL)
Authors: Russell Lisa J. , Akasaka Takashi , Majid Aneela , Sugimoto Kei-ji , Loraine Karran E. , Nagel Inga , Harder Lana , Claviez Alexander , Gesk Stefan , Moorman Anthony V. , Ross Fiona , Mazzullo Helen , Strefford Jonathan C. , Siebert Reiner , Dyer Martin J. S. , Harrison Christine J.
Published: October 2007

Translocations involving the immunoglobulin heavy chain locus (IGH@) at chromosome band 14q32 are common in mature B-cell neoplasms, but are rare in B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Here, we report the translocation, t(6;14)(p22;q32), involving IGH@ as a novel recurrent translocation in 13 BCP-ALL patients. Fluorescence in situ hybridization and long-distance inverse polymerase chain reaction (PCR) identified ID4 as the partner gene. Breakpoints were scattered over a 19kb region centromeric of ID4. Quantitative real-time PCR showed up-regulation of ID4 mRNA. All patients had deletions of CDKN2A and PAX5 located on the short arm of chromosome 9, frequently as a result of an isochromosome, i(9)(q10) (9/13, 69%). This study defines a new subgroup of BCP-ALL characterized by ID4 over-expression and CDKN2A and PAX5 deletions. Preliminary survival data suggest that this subgroup may be associated with a good response to therapy.
Cbfβ-SMMHC impairs differentiation of common lymphoid progenitors and reveals an essential role for RUNX in early B-cell development
Authors: Kuo Ya-Huei , Gerstein Rachel M. , Castilla Lucio H.
Published: October 2007

The core-binding factor (CBF)–associated leukemia fusion protein CBFβ-SMMHC impairs myeloid and lymphoid differentiation. By inhibiting RUNX function, the fusion oncoprotein predisposes specifically to acute myeloid leukemia in both patients and mouse models. We have shown that Cbfβ-SMMHC expression leads to a sustained reduction of circulating B lymphocytes in the mouse. In this study, we demonstrate that the activation of Cbfβ-SMMHC reduces pre–pro-B cells approximately 3-fold and pre-B cells more than 10-fold and that this differentiation block is cell-autonomous. The reduction of pre–pro-B cells coincided with an increase in apoptosis in this population. The number of common lymphoid progenitors (CLPs) were not affected; however, the expression of critical early B-cell factors Ebf1, Tcfe2a, and Pax5 was significantly reduced. In addition, Cbfβ-SMMHC reduced Rag1 and Rag2 expression and impaired V(D)J recombination in the CLPs. Furthermore, CLPs expressing Cbfβ-SMMHC also show inhibition of B cell–specific genes Cd79a, Igll1, VpreB1, and Blk. These results demonstrate that CBF/RUNX function is essential for the function of CLPs, the survival of pre–pro-B cells, and the establishment of a B lineage–specific transcriptional program. This study also provides a mechanistic basis for the myeloid-lineage bias of CBFβ-SMMHC–associated leukemia.
FLT3 D835/I836 mutations are associated with poor disease-free survival and a distinct gene-expression signature among younger adults with de novo cytogenetically normal acute myeloid leukemia lacking FLT3 internal tandem duplications
Authors: Whitman Susan P. , Ruppert Amy S. , Radmacher Michael D. , Mrózek Krzysztof , Paschka Peter , Langer Christian , Baldus Claudia D. , Wen Jing , Racke Frederick , Powell Bayard L. , Kolitz Jonathan E. , Larson Richard A. , Caligiuri Michael A. , Marcucci Guido , Bloomfield Clara D.
Published: October 2007

The prognostic relevance of FLT3 D835/I836 mutations (FLT3-TKD) in cytogenetically normal acute myeloid leukemia (CN-AML) remains to be established. After excluding patients with FLT3 internal tandem duplications, we compared treatment outcome of 16 de novo CN-AML patients with FLT3-TKD with that of 123 patients with wild-type FLT3 (FLT3-WT), less than 60 years of age and similarly treated on Cancer and Leukemia Group B protocols. All FLT3-TKD+ patients and 85% of FLT3-WT patients achieved a complete remission (P = .13). Disease-free survival (DFS) of FLT3-TKD+ patients was worse than DFS of FLT3-WT patients (P = .01; estimated 3-year DFS rates, 31% vs 60%, respectively). In a multivariable analysis, FLT3-TKD was associated with worse DFS (P = .02) independent of NPM1 status and percentage of bone marrow blasts. To gain further biologic insights, a gene-expression signature differentiating FLT3-TKD+ from FLT3-WT patients was identified. The signature (333 probe sets) included overexpression of VNN1, C3AR1, PTPN6, and multiple other genes involved in monocarboxylate transport activity, and underexpression of genes involved in signal transduction regulation. These associations with outcome, other prognostic markers, and the elucidated expression signature enhance our understanding of FLT3-TKD–associated biology and may lead to development of novel therapies that improve clinical outcome of CN-AML patients with FLT3-TKD.
Large scale clustering of protein sequences with FORCE -A layout based heuristic for weighted cluster editing
Authors: Wittkop Tobias , Baumbach Jan , Lobo Francisco P , Rahmann Sven
Published: October 2007

Background

Detecting groups of functionally related proteins from their amino acid sequence alone has been a long-standing challenge in computational genome research. Several clustering approaches, following different strategies, have been published to attack this problem. Today, new sequencing technologies provide huge amounts of sequence data that has to be efficiently clustered with constant or increased accuracy, at increased speed.

Results

We advocate that the model of weighted cluster editing, also known as transitive graph projection is well-suited to protein clustering. We present the FORCE heuristic that is based on transitive graph projection and clusters arbitrary sets of objects, given pairwise similarity measures. In particular, we apply FORCE to the problem of protein clustering and show that it outperforms the most popular existing clustering tools (Spectral clustering, TribeMCL, GeneRAGE, Hierarchical clustering, and Affinity Propagation). Furthermore, we show that FORCE is able to handle huge datasets by calculating clusters for all 192 187 prokaryotic protein sequences (66 organisms) obtained from the COG database. Finally, FORCE is integrated into the corynebacterial reference database CoryneRegNet.

Conclusion

FORCE is an applicable alternative to existing clustering algorithms. Its theoretical foundation, weighted cluster editing, can outperform other clustering paradigms on protein homology clustering. FORCE is open source and implemented in Java. The software, including the source code, the clustering results for COG and CoryneRegNet, and all evaluation datasets are available at http://gi.cebitec.uni-bielefeld.de/comet/force/.