bluuebunny/crossref_metadata_2025 huggingface dataset:
Epithelial neutrophil-activating peptide-78 recruits neutrophils into pleural effusion
Authors: Liu G-N. , Shi H-Z. , Xie Z-H. , Shen H-H. , Huang H-Q. , Deng J-M. , Liang Q-L. , Wu Y-B.
Published: December 2008

The aim of this study was to investigate the presence of epithelial neutrophil-activating peptide (ENA)-78 in pleural effusions, as well as the chemoattractant activity of pleural ENA-78 on neutrophils.

Pleural effusion and serum samples were collected from 75 patients who presented to the respiratory institute (19 with malignant pleural effusion, 21 with tuberculous pleural effusion, 18 with infectious pleural effusion and 17 with transudative pleural effusion). The concentrations of ENA-78, myeloperoxidase and neutrophil elastase were determined, and the chemoattractant activity of ENA-78 for neutrophils bothin vitroandin vivowas also observed.

The concentrations of ENA-78, myeloperoxidase and neutrophil elastase in infectious pleural effusion were significantly higher than those in malignant, tuberculous and transudative groups, respectively (all p<0.01). Infectious pleural fluid was chemotactic for neutrophilsin vitroand anti-ENA-78 antibody could partly inhibit these chemotactic effects. Intrapleural administration of ENA-78 produced a marked progressive influx of neutrophils into pleural space.

Compared with noninfectious pleural effusion, ENA-78 appeared to be increased in infectious pleural effusion. Our data suggested that ENA-78 was able to induce neutrophil infiltration into pleural space and might be responsible for pleural neutrophil degranulation.
Assessment of the feasibility of exon 45–55 multiexon skipping for duchenne muscular dystrophy
Authors: van Vliet Laura , de Winter Christa L , van Deutekom Judith CT , van Ommen Gert-Jan B , Aartsma-Rus Annemieke
Published: December 2008

Background

The specific skipping of an exon, induced by antisense oligonucleotides (AON) during splicing, has shown to be a promising therapeutic approach for Duchenne muscular dystrophy (DMD) patients. As different mutations require skipping of different exons, this approach is mutation dependent. The skipping of an entire stretch of exons (e.g. exons 45 to 55) has recently been suggested as an approach applicable to larger groups of patients. However, this multiexon skipping approach is technically challenging. The levels of intended multiexon skips are typically low and highly variable, and may be dependent on the order of intron removal. We hypothesized that the splicing order might favor the induction of multiexon 45–55 skipping.

Methods

We here tested the feasibility of inducing multiexon 45–55 in control and patient muscle cell cultures using various AON cocktails.

Results

In all experiments, the exon 45–55 skip frequencies were minimal and comparable to those observed in untreated cells.

Conclusion

We conclude that current state of the art does not sufficiently support clinical development of multiexon skipping for DMD.
Association of the germline TP53R337H mutation with breast cancer in southern Brazil
Authors: Assumpção Juliana G , Seidinger Ana Luíza , Mastellaro Maria José , Ribeiro Raul C , Zambetti Gerard P , Ganti Ramapriya , Srivastava Kumar , Shurtleff Sheila , Pei Deqing , Zeferino Luiz Carlos , Dufloth Rozany M , Brandalise Silvia Regina , Yunes José Andres
Published: December 2008

Background

The germline TP53-R337H mutation is strongly associated with pediatric adrenocortical tumors (ACT) in southern Brazil; it has low penetrance and limited tissue specificity in most families and therefore is not associated with Li-Fraumeni syndrome. However, other tumor types, mainly breast cancer, have been observed in carriers of several unrelated kindreds, raising the possibility that the R337H mutation may also contribute to breast tumorigenesis in a genetic background-specific context.

Methods

We conducted a case-control study to determine the prevalence of the R337H mutation by sequencing TP53 exon 10 in 123 women with breast cancer and 223 age- and sex-matched control subjects from southern Brazil. Fisher's test was used to compare the prevalence of the R337H.

Results

The R337H mutation was found in three patients but in none of the controls (p = 0.0442). Among the carriers, two had familial history of cancer meeting the Li-Fraumeni-like criteria. Remarkably, tumors in each of these three cases underwent loss of heterozygosity by eliminating the mutant TP53 allele rather than the wild-type allele. Polymorphisms were identified within the TP53 (R72P and Ins16) and MDM2 (SNP309) genes that may further diminish TP53 tumor suppressor activity.

Conclusion

These results demonstrate that the R337H mutation can significantly increase the risk of breast cancer in carriers, which likely depends on additional cooperating genetic factors. These findings are also important for understanding how low-penetrant mutant TP53 alleles can differentially influence tumor susceptibility.
Long-Term Smoking Cessation Outcomes Among Childhood Cancer Survivors in the Partnership for Health Study
Authors: Emmons Karen M. , Puleo Elaine , Mertens Ann , Gritz Ellen R. , Diller Lisa , Li Frederick P.
Published: December 2008

Purpose

Partnership for Health (PFH) was found to increase smoking cessation among smokers in the Childhood Cancer Survivors Study (CCSS) at the 8- and 12-month postbaseline follow-up. This report provides outcomes at 2 to 6 years postbaseline; the primary outcome is a four-category smoking status variable (quit at all follow-ups, quit at final follow-up only, smoker at all follow-ups, and smoker at final follow-up only); quit attempts among those who reported smoking at the final follow-up is a secondary outcome.

Methods

PFH was a randomized control trial with two conditions, peer phone counseling (PC) and self-help (SH), that involved smokers (n = 796) enrolled in the CCSS cohort.

Results

Long-term quit rates were higher in PC versus SH participants. Long-term smoking cessation outcomes were lower among those who were nicotine dependent, of lower educational levels, and among men, and were higher among those who used nicotine replacement therapy and who had higher levels of situational self-efficacy. There were no significant differences in relapse rates between conditions or in quit attempts among continued smokers.

Conclusion

Cessation rates continue to be significantly higher among participants in the PC condition versus SH, although the differences were not large. This article highlights differences in long-term engagement with smoking cessation among those who received the intervention.
Role of Androgen Deprivation Therapy for Node-Positive Prostate Cancer
Authors: Wong Yu-Ning , Freedland Stephen , Egleston Brian , Hudes Gary , Schwartz J. Sanford , Armstrong Katrina
Published: December 2008

Purpose

To determine the impact of adjuvant androgen deprivation therapy (ADT) for patients who have node-positive prostate cancer in the prostate-specific antigen (PSA) era.

Patients and Methods

We used linked Surveillance, Epidemiology and End Results-Medicare data to construct a cohort of men who underwent radical prostatectomy (RP) between 1991 and 1999 and who had positive regional lymph nodes. We classified men as receiving adjuvant ADT if they received ADT within 120 days of RP, and we compared them to the men who had not received adjuvant ADT. We used propensity scores to balance potential confounders of receiving adjuvant ADT (ie, tumor characteristics, extent of nodal disease, demographics, receipt of radiation therapy) and Cox proportional hazard methods to measure the impact of adjuvant ADT on overall survival (OS), stratified by propensity score quintile. We conducted a sensitivity analysis that used 90, 150, 180, and 365 days as the definition for adjuvant ADT.

Results

A total of 731 men were identified, 209 of whom received ADT within 120 days of RP. There was no statistically significant difference in OS between the adjuvant ADT and non-ADT group (HR, 0.97; 95% CI, 0.71 to 1.27). There was no statistically significant survival difference with 90, 150, 180, and 365 days as the adjuvant ADT definition.

Conclusion

Deferring immediate ADT in men with positive lymph nodes after RP may not significantly compromise survival. Because observational studies should be considered hypothesis-generating studies, these results should be validated in a prospective fashion in a similar patient population.
The International Neuroblastoma Risk Group (INRG) Staging System: An INRG Task Force Report
Authors: Monclair Tom , Brodeur Garrett M. , Ambros Peter F. , Brisse Hervé J. , Cecchetto Giovanni , Holmes Keith , Kaneko Michio , London Wendy B. , Matthay Katherine K. , Nuchtern Jed G. , von Schweinitz Dietrich , Simon Thorsten , Cohn Susan L. , Pearson Andrew D.J.
Published: December 2008

Purpose

The International Neuroblastoma Risk Group (INRG) classification system was developed to establish a consensus approach for pretreatment risk stratification. Because the International Neuroblastoma Staging System (INSS) is a postsurgical staging system, a new clinical staging system was required for the INRG pretreatment risk classification system.

Methods

To stage patients before any treatment, the INRG Task Force, consisting of neuroblastoma experts from Australia/New Zealand, China, Europe, Japan, and North America, developed a new INRG staging system (INRGSS) based on clinical criteria and image-defined risk factors (IDRFs). To investigate the impact of IDRFs on outcome, survival analyses were performed on 661 European patients with INSS stages 1, 2, or 3 disease for whom IDRFs were known.

Results

In the INGRSS, locoregional tumors are staged L1 or L2 based on the absence or presence of one or more of 20 IDRFs, respectively. Metastatic tumors are defined as stage M, except for stage MS, in which metastases are confined to the skin, liver, and/or bone marrow in children younger than 18 months of age. Within the 661-patient cohort, IDRFs were present (ie, stage L2) in 21% of patients with stage 1, 45% of patients with stage 2, and 94% of patients with stage 3 disease. Patients with INRGSS stage L2 disease had significantly lower 5-year event-free survival than those with INRGSS stage L1 disease (78% ± 4% v 90% ± 3%; P = .0010).

Conclusion

Use of the new staging (INRGSS) and risk classification (INRG) of neuroblastoma will greatly facilitate the comparison of risk-based clinical trials conducted in different regions of the world.
Prophylactic Cranial Irradiation in Extensive Disease Small-Cell Lung Cancer: Short-Term Health-Related Quality of Life and Patient Reported Symptoms—Results of an International Phase III Randomized Controlled Trial by the EORTC Radiation Oncology and Lung Cancer Groups
Authors: Slotman Berend J. , Mauer Murielle E. , Bottomley Andrew , Faivre-Finn Corinne , Kramer Gijs W.P.M. , Rankin Elaine M. , Snee Michael , Hatton Matthew , Postmus Pieter E. , Collette Laurence , Senan Suresh
Published: December 2008

Purpose

Prophylactic cranial irradiation (PCI) in patients with extensive-disease small-cell lung cancer (ED-SCLC) leads to significantly fewer symptomatic brain metastases and improved survival. Detailed effects of PCI on health-related quality of life (HRQOL) are reported here.

Patients and Methods

Patients (age, 18 to 75 years; WHO ≤ 2) with ED-SCLC, and any response to chemotherapy, were randomly assigned to either observation or PCI. Health-related quality of life (HRQOL) and patient-reported symptoms were secondary end points. The European Organisation for the Research and Treatment of Cancer core HRQOL tool (Quality of Life Questionnaire C30) and brain module (Quality of Life Questionnaire Brain Cancer Module) were used to collect self-reported patient data. Six HRQOL scales were selected as primary HRQOL end points: global health status; hair loss; fatigue; and role, cognitive and emotional functioning. Assessments were performed at random assignment, 6 weeks, 3 months, and then 3-monthly up to 1 year and 6-monthly thereafter.

Results

Compliance with the HRQOL assessment was 93.7% at baseline and dropped to 60% at 6 weeks. Short-term results up to 3 months showed that there was a negative impact of PCI on selected HRQOL scales. The largest mean difference between the two arms was observed for fatigue and hair loss. The impact of PCI on global health status as well as on functioning scores was more limited. For global health status, the observed mean difference was eight points on a scale 0 to 100 at 6 weeks (P = .018) and 3 months (P = .055).

Conclusion

PCI should be offered to all responding ED SCLC patients. Patients should be informed of the potential adverse effects from PCI. Clinicians should be alert to these; monitor their patients; and offer appropriate support, clinical, and psychosocial care.
Oral mTOR Inhibitor Everolimus in Patients With Gemcitabine-Refractory Metastatic Pancreatic Cancer
Authors: Wolpin Brian M. , Hezel Aram F. , Abrams Thomas , Blaszkowsky Lawrence S. , Meyerhardt Jeffrey A. , Chan Jennifer A. , Enzinger Peter C. , Allen Brittany , Clark Jeffrey W. , Ryan David P. , Fuchs Charles S.
Published: December 2008

Purpose

The PI3K/Akt/mTOR pathway is activated in the majority of pancreatic cancers, and inhibition of this pathway has antitumor effects in preclinical studies. We performed a multi-institutional, single-arm, phase II study of RAD001(everolimus), an oral inhibitor of mTOR, in patients who experienced treatment failure on first-line therapy with gemcitabine.

Patients and Methods

Thirty-three patients with gemcitabine-refractory, metastatic pancreatic cancer were treated continuously with RAD001 at 10 mg daily. Prior treatment with fluorouracil in the perioperative setting was allowed. Patients were observed for toxicity, treatment response, and survival.

Results

Treatment with single-agent RAD001 was well-tolerated; the most common adverse events were mild hyperglycemia and thrombocytopenia. No patients were removed from the study because of drug-related adverse events. No complete or partial treatment responses were noted, and only seven patients (21%) had stable disease at the first restaging scans performed at 2 months. Median progression-free survival and overall survival were 1.8 months and 4.5 months, respectively. One patient (3%) had a biochemical response, defined as ≥ 50% reduction in serum CA19-9.

Conclusion

Although well-tolerated, RAD001 administered as a single-agent had minimal clinical activity in patients with gemcitabine-refractory, metastatic pancreatic cancer. Future studies in metastatic pancreatic cancer should assess the combination of mTOR inhibitors with other agents and/or examine inhibitors of other components of the PI3K/Akt/mTOR pathway.
Interplay between Rab5 and PtdIns(4,5)P2 controls early endocytosis in theDrosophilagermline
Authors: Compagnon Julien , Gervais Louis , Roman Mabel San , Chamot-Bœuf Sophy , Guichet Antoine
Published: December 2008

Phosphoinositides have emerged as key regulators of membrane traffic through their control of the localization and activity of several effector proteins. Both Rab5 and phosphatidylinositol (4,5)-bisphosphate [PtdIns(4,5)P2] are involved in the early steps of the clathrin-dependent endocytic pathway, but little is known about how their functions are coordinated. We have studied the role of PtdIns(4,5)P2 and Rab5 in the Drosophila germline during oogenesis. We found that Rab5 is required for the maturation of early endocytic vesicles. We show that PtdIns(4,5)P2 is required for endocytic-vesicle formation, for Rab5 recruitment to endosomes and, consistently, for endocytosis. Furthermore, we reveal a previously undescribed role of Rab5 in releasing PtdIns(4,5)P2, PtdIns(4,5)P2-binding budding factors and F-actin from early endocytic vesicles. Finally, we show that overexpressing the PtdIns(4,5)P2-synthesizing enzyme Skittles leads to an endocytic defect that is similar to that seen in rab5 loss-of-function mutants. Hence, our results argue strongly in favor of the hypothesis that the Rab5-dependant release of PtdIns(4,5)P2 from endosomes that we discovered in this study is crucial for endocytosis to proceed.
BDNF splice variants from the second promoter cluster support cell survival of differentiated neuroblastoma upon cytotoxic stress
Authors: Baj Gabriele , Tongiorgi Enrico
Published: December 2008

The neurotrophin brain-derived neurotrophic factor (BDNF) is a key survival factor for neural cells. In particular, in neuroblastoma tumour cells, expression of the BDNF/TrkB autocrine signalling system promotes a more malignant phenotype and resistance to chemotherapy. The human BDNF gene contains two clusters of upstream exons encoding the 5′UTR (exon 1 to exon 3 and exon 4 to exon 9a), these are alternatively spliced to a common exon 9, which contains the coding region and the 3′UTR. At least 34 different BDNF mRNA transcripts can be generated, although their physiological role is still unknown. The purpose of this study is to determine which BDNF transcript is involved in cell survival of the human neuroblastoma cell lines SH-SY-5Y (single-copy MYCN) and SK-N-BE (amplified MYCN). Expression of human BDNF mRNAs encoding all possible isoforms was characterised in the two neuroblastoma cell lines. We then investigated whether selective silencing of the different BDNF mRNAs using specific siRNAs could reduce cell survival in response to serum deprivation or the anticancer drugs cisplatin, doxorubicin and etoposide. We found that three isoforms located in the second exon cluster are essential for neuroblastoma cell survival under cytotoxic stress. Notably, promoters of the second exon cluster, but not the first, are controlled by Ca2+-sensitive elements.
Different GPI-attachment signals affect the oligomerisation of GPI-anchored proteins and their apical sorting
Authors: Paladino Simona , Lebreton Stephanie , Tivodar Simona , Campana Vincenza , Tempre Rosaria , Zurzolo Chiara
Published: December 2008

To understand the mechanism involved in the apical sorting of glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) we fused to the C-terminus of GFP the GPI-anchor-attachment signal of the folate receptor (FR) or of the prion protein (PrP), two native GPI-anchored proteins that are sorted apically or basolaterally, respectively, in MDCK cells. We investigated the behaviour of the resulting fusion proteins GFP-FR and GFP-PrP by analysing three parameters: their association with DRMs, their oligomerisation and their apical sorting. Strikingly, we found that different GPI-attachment signals differently modulate the ability of the resulting GFP-fusion protein to oligomerise and to be apically sorted. This is probably owing to differences in the GPI anchor and/or in the surrounding lipid microenvironment. Accordingly, we show that addition of cholesterol to the cells is necessary and sufficient to drive the oligomerisation and consequent apical sorting of GFP-PrP, which under control conditions does not oligomerise and is basolaterally sorted.
Localization of Inv in a distinctive intraciliary compartment requires the C-terminal ninein-homolog-containing region
Authors: Shiba Dai , Yamaoka Yoshihisa , Hagiwara Haruo , Takamatsu Tetsuro , Hamada Hiroshi , Yokoyama Takahiko
Published: December 2008

The primary cilium is an antenna-like structure extending from the surface of most vertebrate cells. Loss or mutation of ciliary proteins can lead to polycystic kidney disease and other developmental abnormalities. inv mutant mice develop multiple renal cysts and are a model for human nephronophthisis type 2. The mouse Inv gene encodes a 1062-amino-acid protein that is localized in primary cilia. In this study, we show that the Inv protein (also known as inversin) is localized at a distinctive proximal segment of the primary cilium, using GFP-tagged Inv constructs and anti-Inv antibody. We named this segment the Inv compartment of the cilium. Further investigation of the Inv protein showed that 60 amino acids at its C-terminal, which contains ninein homologous sequences, are crucial for its localization to the Inv compartment. Fluorescence recovery after photobleaching analysis revealed that the Inv protein was dynamic within this compartment. These results suggest that localization of the Inv protein to the Inv compartment is actively regulated. The present study revealed that the primary cilium has a distinct molecular compartment in the body of the primary cilium with a specific confining and trafficking machinery that has not been detected previously by morphological examination.
Analytical and numerical investigation of the optimum pressure distribution along a low-pressure axial fan blade
Authors: Pascu M , Miclea M , Epple P , Delgado A , Durst F
Published: December 2008

In the field of axial flow turbomachines, the two-dimensional cascade model is often used experimentally or numerically to investigate fundamental flow characteristics and overall performance of the impeller. The core of the present work is a design method for axial fan cascades aiming to derive inversely the optimum blade shape based on the requirements of the impeller and not using any predefined aerofoil profiles.

While most design strategies based on the aerofoil theory assume constant total pressure at all streamlines, i.e. free-vortex flow, this paper investigates the possibility of varying the total pressure along the blade and based on that, an analytical expression of the outlet blade angle is determined. When computing the blade profile at a specified radius, critical parameters reflecting on the flow characteristics are observed and adjusted (i.e. sufficient lift and controlled deceleration of the flow on the contour) so that the resulting profile is derived for minimum losses.

The validation of this design strategy is given by the numerical results obtained when employed as an optimization tool for an industrial fan: 10–20 per cent absolute increase in the static efficiency of the optimized impeller.
Natural convection flow of a non-Newtonian power-law fluid from a slotted vertical surface with uniform surface heat flux
Authors: Gorla R S R , Hossain M A
Published: December 2008

In the present paper, the natural convection flow of an Ostwalde—de Waele type power-law non-Newtonian fluid past a uniformly heated vertical slotted surface has been investigated numerically. The equations governing the flow and heat transfer are reduced to local non-similarity form. The transformed boundary-layer equations are solved numerically using implicit finite-difference method for values of ξ in the interval [0, ∞]. Solutions for heat transfer rate obtained for the rigid surface compared well with those documented in the published literature. From the present analysis, it is observed that an increase in ξ leads to increasing the skin-friction as well as reduction in heat transfer at the surface. As the power-law index n increases, the friction factor as well as the surface heat transfer increases.
Alternative method to evaluate discharge coefficients. Part 2: Case study
Authors: Gault R I , Thornhill D J , Fleck R
Published: December 2008

The purpose of this article is to apply an alternative method whereby discharge coefficients can be estimated for the flow through a poppet valve at various lifts. Presented is the development of an operational quasi-steady flow rig. An engine cylinder head poppet valve was used as the case study. The requirement to directly measure mass flowrates using a standard conventional steady flow apparatus has been eliminated. Transient mass flowrates, pressures and temperatures of air during an inflow test for a poppet valve at various lifts were measured. Mass flowrates were also calculated from measured cylinder gas pressures and corrected for heat transfer. Using both methods to determine the mass flowrates, isentropic discharge coefficients were calculated and shown to compare within>4.0 per cent of steady flow data. A computational fluid dynamics (CFD) validation of the quasi-steady flow rig is also presented.
Flow structures downstream of the horizontal cylinder laid on a plane surface
Authors: Akoz M Sami
Published: December 2008

The complex vortical flow structure arises from the interaction between the flow and a pipeline on seabed, causing erosion scour around the pipeline, which is a threat to the stability of the structure. The viscous flow past a circular cylinder laid on a horizontal bed is analysed experimentally using the particle image velocimetry image technique to understand the vortical flow characteristics downstream of the cylinder. The experiments were conducted in a closed-loop water channel with Reynolds numbers, in the range of 1000 ≤ ReD ≤ 7000 based on the cylinder diameter. To provide a detailed evaluation of the properties of the flow structure behind the cylinder, instantaneous and time-averaged patterns of velocity vector field, corresponding vorticity contours, streamline topology, and Reynolds stress concentrations were presented. The point of the boundary layer detachment from the cylinder surface and the lengths of the primary and secondary downstream separation regions were determined as a function of Reynolds numbers. Instantaneous velocity fields clearly indicate the scour mechanism downstream of the horizontal cylinder.
Developments in turbomachinery internal air systems
Authors: Chew J W
Published: December 2008

Development of turbomachinery technology, including aircraft propulsion, has been an outstanding achievement of the last 50 years and, as illustrated by Ruffles in his paper ‘The future of aircraft propulsion’ (2000), further advances are expected in the future. Here, one particular aspect of turbomachinery technology, the internal air system is considered. An article by Dixon et al., published by the Institution of Mechanical Engineers in 2004, shows how computational modelling has become central to the design process and the importance of the internal air system in engine design. Bayley and Conway's 1964 paper, motivated by shortcomings in industrial design methods and understanding, was one of the first investigations of flow and heat transfer in rotating disc cavities typical of internal air systems. During the study, a theoretical or numerical treatment was considered intractable and so experiments were undertaken. These paved the way for an extensive research in this area. Today, the use of computational fluid dynamics (CFD) in industry for internal air flow prediction is commonplace. In this review, it is shown that the unshrouded disc cavity flow considered by Bayley and Conway is still challenging for modern CFD methods, and so the experimental data remain of interest to researchers in the field.
Some remarks on the paper ‘A unified tensor approach to the analysis of mechanical systems’ by A. A. Fogarasy and M. R. Smith
Authors: Altenbach H
Published: December 2008

The tensor calculus is a powerful mathematical tool in the analysis of mechanical problems (or generally, of problems in physics). The aim of Fogarasy and Smith's ‘A unified tensor approach to the analysis of mechanical systems’ is to demonstrate this fact considering a problem of dynamical analysis of mechanisms. Fogarasy and Smith are applying the traditional approach in tensor calculus, which comes originally from the mathematics. This implies the a priori introduction of coordinates, which is usual in the analysis of mechanisms. Later the tensor calculus is used for the discussion of the basic equations and their mathematical handling. In this sense, the results obtained by Fogarasy and Smith are mathematically correct, and the interested reader can now have many fruitful and stimulating ideas.
Optimization of dynamic parameters for a traction-type passenger elevator using a dynamic byte coding genetic algorithm
Authors: Mei D , Du X , Chen Z
Published: December 2008

To decrease the vibration and improve the dynamic performance of traction-type passenger elevators, an accurate vertical dynamic model with nine degrees of freedom for a gearless 2: 1 traction-type passenger elevator system is presented. Then, an optimization model of dynamic parameters for this type of passenger elevator is proposed based on the dynamic model. The optimization model takes the amplitude of vibration acceleration response of the elevator cage as the objective function. Various exciting forces and various working conditions can be considered by using corresponding weight coefficients in the objective function. To get higher efficiency and stronger robustness of optimized value, a dynamic byte coding genetic algorithm in solving the optimization model by combining the advantages of binary coding method with dynamic parameter encoding method is proposed, and the optimal solution is verified by sensitivity analysis. A practical engineering optimization for a 2: 1 traction-type passenger elevator system shows that the optimization model and method of dynamic parameters proposed in this article are effective.
A disc to air heat flux error and uncertainty analysis applied to a turbomachinery test rig design
Authors: Cooke A , Childs P , Sayma N , Long C A
Published: December 2008

This article describes a Monte Carlo simulation-based error and an uncertainty analysis for values of disc to air heat fluxes as part of the design of an experimental axial turbine test rig. This work is of interest for those who study heat transfer and measurement or the design and use of experimental test rigs.

An inverse analysis of theoretical disc surface temperatures was performed for different thermocouple configurations to compare the errors and uncertainties resulting from each to establish whether there was any configuration that would return the lowest magnitudes of error and uncertainty and hence influence the location of the proposed instrumentation.

It is shown that great care needs to be taken when using an analysis of this kind together with temperature measurements having realistic and typical uncertainty values. This is because such an analysis is purely analytical, and any small fluctuations in the inputs, such as typical thermocouple uncertainties and noise, result in the process of an inverse analysis becoming unstable. This instability has two effects: (a) the returned values of heat flux have an inbuilt bias error and (b) the magnitudes of uncertainty can exceed>100 per cent.
An experimental and numerical study of the expansion forming of a thick-walled microgroove tube
Authors: Tang D , Peng Y , Li D
Published: December 2008

CO2 refrigerant-based air conditioning and refrigeration (ACR) is an increasing concern in many industrial sectors for its zero ozone depletion potential. One of the major requirements in its application is the forming technology of thick-walled tube according to the extremely high pressure working conditions of the ACR system. This article presents a study on the expansion process joining the thick-walled microgroove copper tube to aluminium fins. Experiments of the forming process have been carried out. Finite-element models are developed to investigate the deformation of overall and local structures. Evaluation of the joining quality along the longitude axis of the tube is first attempted. The agreement of the results on the contact surface profile confirms that the joint is far away from full contact in the axial section. Formation mechanism of the unexpected contact status lies in displacement of the contact points along the section of the fin collar, which is mainly related to the expanding ratio. To improve the forming quality, discussion on processing parameters and die geometry is conducted. Results show that the expanding ratio is the major factor influencing the thermal—mechanical performance of the joint and 2–6 per cent can be the comprehensively beneficial range for a thick-walled ACR tube; average contact pressure can reach 1.76 Mpa under proper set. The results are helpful for improving the energy efficiency ratio performance of the natural refrigerant-based system.
Design guide of bolt locations for bolted-joint plates considering dynamic characteristics
Authors: Yoo J , Hong S-J , Choi J S , Kang Y J
Published: December 2008

In this study, a simplified finite-element (FE) modelling method is proposed, which simulates the dynamic characteristics of a bolted-joint structure having a large interface area, by utilizing the concept of the cone-frusta method for the jointed parts and spring elements to represent the contact effects occurring in the interfaced area. A method for providing design guidelines for the selection of additional bolt locations is also proposed based on the natural frequencies and mode shapes of the bolted-joint plates. The natural frequency of a specific mode and its mode shape can be controlled by adjusting bolt locations and the number of bolts, considering the effects of the relative deformations in mode shapes, at the plate interfaces. The proposed modelling method and design guidelines are verified based on the experimental results and the FE analysis.
Continuum element method for analysing free-vibration behaviour of crankshafts
Authors: Tang B
Published: December 2008

The continuum element method for determining natural frequencies and mode shapes of the crankshaft is developed. The crankshaft is modelled into a series of space continuum beam elements. They include the effects of shear deformation and rotary inertia of the cross-section. An analytical expression for the dynamic stiffness matrix for each of the elements is derived. The overall dynamic stiffness matrix of the crankshaft is assembled in turn. The natural frequencies are calculated with the Wittrick—Williams algorithm. The mode shapes of the crankshaft are computed by the recursive Newton method. Two illustrative crankshafts are discussed to evaluate the performance of the method. Solutions calculated by the finite element method and experimental work are also enumerated for comparison. The results show that the current method is appropriate for free vibration analysis of the crankshaft.
Experimental study of a hydrodynamic vortex separator
Authors: Egarr D A , Faram M G , O'Doherty T , Syred N
Published: December 2008

A hydrodynamic vortex separator (HDVS) has been studied under laboratory conditions by using a specifically designed rig. Pressure tapping points placed at eight locations, six external and two internal, have revealed an even radial pressure distribution on the outer walls and central shaft. The ability of the HDVS to separate particulates has been studied. The particulates have been characterized by measurements of particle diameter and settling velocity, which have allowed efficiency cusps to be plotted against dimensionless groups used by other researchers. Owing to an unsatisfactory reduction of the data to a single curve by plotting the efficiency against dimensionless groups, an efficiency law has been determined based on the logistic equation and describes the separation efficiency in terms of the inlet flowrate, volume of the separator, and particle diameter and density.
Design of experiments-based stability and control derivative modelling
Authors: Omran A , Landman D , Newman B
Published: December 2008

This article investigates modelling aircraft non-dimensional aerodynamic-propulsive coefficients by using a design of experiment technique based on a linear parameter variation model. A case study is conducted to estimate the stability and control derivatives from aircraft response behaviour in longitudinal motion. For demonstrating technique feasibility, a non-linear simulator for the F-16 was used to assess the proposed approach. A set of doublet elevator and throttle inputs is initially executed at different locations over the operational flight envelope. Then, the aircraft response is used in identifying the derivative variations with velocity, altitude, aircraft mass, and centre of gravity position. A sequential experiment using a factorial design and augmented face central axial points was employed to model the variation. The validity of the proposed method was evaluated by comparing the estimated and actual variation of the derivatives. The proposed approach is generally applicable for wind tunnel and flight tests.
Subsidence of uncemented stems in osteoporotic and non-osteoporotic cadaveric femora
Authors: Mears S C , Richards A M , Knight T A , Belkoff S M
Published: December 2008

The increased use of uncemented stems for hip arthroplasty and of fast-recovery protocols in elderly patients make initial stem stability and resistance to fracture critical factors in osteoporotic bone. In this paper, the subsidence and failure of two uncemented stem designs (M/L Taper and VerSys Fullcoat, Zimmer, Inc, Warsaw, Indiana, USA) in osteoporotic and non-osteoporotic cadaveric femora were compared under simulated walking conditions (axial compression and external rotation). Osteoporotic femora implanted with either stem design failed significantly more frequently than did non-osteoporotic femora. Femora implanted with the M/L stems (seven of ten by 1000 cycles) fractured earlier than did femora implanted with the Fullcoat stem (one of ten by 1000 cycles). The use of early weight-bearing protocols with uncemented stem designs in osteoporotic bone should be approached with caution.
Currently available medical engineering degrees in the UK. Part 2: Postgraduate degrees
Authors: Joyce T
Published: December 2008

This paper considers taught medical engineering MSc degrees, based on mechanical engineering, which are provided in the UK. Currently there are 19 institutions which provide such postgraduate degree programmes. These are the University of Aberdeen, University of Bath, University of Bradford, Brunel University, University of Dundee, University of Hull, Imperial College London, Keele University, King's College London, University of Leeds, University of Liverpool, University of Nottingham, University of Oxford, Queen Mary University of London, University of Southampton, University of Strathclyde, University of Surrey, University of Ulster, and University of Warwick. While most courses are delivered on a 1 year full-time basis, other delivery modes are also available. Relatively few modules are offered as distance learning or short courses. A wide range of modules are offered by the various universities for the different taught MSc degrees. Common modules include biomaterials and biomechanics. The medical-engineering-related modules offered by a number of universities are also made available to students on allied MSc programmes and undergraduate degrees in medical engineering.
A haptic unit designed for magnetic-resonance-guided biopsy
Authors: Tse Z T H , Elhawary H , Rea M , Young I , Davis B L , Lamperth M
Published: December 2008

The magnetic fields present in the magnetic resonance (MR) environment impose severe constraints on any mechatronic device present in its midst, requiring alternative actuators, sensors, and materials to those conventionally used in traditional system engineering. In addition the spatial constraints of closed-bore scanners require a physical separation between the radiologist and the imaged region of the patient. This configuration produces a loss of the sense of touch from the target anatomy for the clinician, which often provides useful information. To recover the force feedback from the tissue, an MR-compatible haptic unit, designed to be integrated with a five-degrees-of-freedom mechatronic system for MR-guided prostate biopsy, has been developed which incorporates position control and force feedback to the operator. The haptic unit is designed to be located inside the scanner isocentre with the master console in the control room. MR compatibility of the device has been demonstrated, showing a negligible degradation of the signal-to-noise ratio and virtually no geometric distortion. By combining information from the position encoder and force sensor, tissue stiffness measurement along the needle trajectory is demonstrated in a lamb liver to aid diagnosis of suspected cancerous tissue.
Stress shielding and stress concentration of contemporary epiphyseal hip prostheses
Authors: Cristofolini L , Juszczyk M , Taddei F , Field R E , Rushton N , Viceconti M
Published: December 2008

After the first early failures, proximal femoral epiphyseal replacement is becoming popular again. Prosthesis-to-bone load transfer is critical for two reasons: stress shielding is suspected of being responsible for a number of failures of early epiphyseal prostheses; stress concentration is probably responsible of the relevant number of early femoral neck fractures in resurfaced patients. The scope of this work was to experimentally investigate the load transfer of a commercial epiphyseal prosthesis (Birmingham Hip Replacement (BHR)) and an innovative prototype proximal epiphyseal replacement. To investigate bone surface strain, ten cadaveric femurs were instrumented with 15 triaxial strain gauges. In addition the cement layer of the prototype was instrumented with embedded gauges to estimate the strain in the adjacent trabecular bone. Six different loading configurations were investigated, with and without muscles. For the BHR prosthesis, significant stress shielding was observed on the posterior side of the head—neck region (the strain was halved); a pronounced stress concentration was observed on the anterior surface (up to five times in some specimens); BHR was quite sensitive to the different loading configurations. For the prototype, the largest stress shielding was observed in the neck region (lower than the BHR; alteration less than 20 per cent); some stress concentration was observed at the head region, close to the rim of the prosthesis (alteration less than 20 per cent); the different loading configurations had similar effects. Such large alterations with respect to the pre-operative conditions were found only in regions where the strain level was low. Conversely, alterations were moderate where the strain was higher. Thus, prosthesis-to-bone load transfer of both devices has been elucidated; the prototype preserved a stress distribution closer to the physiological condition.
Applying tactile sensing with piezoelectric materials for minimally invasive surgery and magnetic-resonance-guided interventions
Authors: Hamed A M , Tse Z T H , Young I , Davies B L , Lampérth M
Published: December 2008

Medical technologies have undergone significant development to overcome the problems inherent in minimally invasive surgery such as inhibited manual dexterity, reduced visual information, and lack of direct touch feedback to make it easier for surgeons to operate. A minimally invasive tool incorporating haptic feedback is being developed to increase the effectiveness of diagnostic procedures by providing force feedback. Magnetic resonance imaging guidance is possible to allow tool localization; however, this engenders the requirement of magnetic resonance compatibility on the device. This paper describes the work done towards developing a sensing device using piezoelectric sensor elements to locate subsurface inclusions in soft substrates, with its magnetic resonance compatibility tested in a 1.5 T scanner. Results show that the position of a hard inclusion can be determined.
Development of a three-degrees-of-freedom moveable platform for providing postural perturbations
Authors: Chen C-L , Lee J-Y , Horng R-F , Lou S-Z , Su F-C
Published: December 2008

The purpose of this study was to design and develop a three-degrees-of-freedom moveable platform to provide postural perturbations for balance assessment and training. The platform consists of three motion mechanisms, which can provide forward—backward translation, upward—downward tilt, and clockwise—counterclockwise rotation. This platform can move in any of its degrees of freedom separately or simultaneously. The precision and accuracy of the platform movement were examined by calculating the standard deviations in repeated trials and comparing the real amplitude and velocity of the movement with the preset values. All the standard deviations in repeated trials were small in that the variation coefficients were less than 2 per cent, except that in the highest-velocity test, and all the mean differences were less than 1 mm for translational and 1° for tilt or rotational perturbations. The results demonstrated that the platform is a reliable and valid instrument for providing postural perturbations. The preliminary investigation of the kinematic postural responses to translational and tilt perturbation showed that this platform is a useful apparatus for balance research. Potential applications of this platform include investigation of the postural responses to yaw rotation or any combination of its degrees of freedom and studying the effects of perturbation-based balance-training programmes provided by this platform.
Using qualitative spatial reasoning in the conceptual design stage of a mechanical system
Authors: Feng H , Shao C , Xu Y
Published: December 2008

A qualitative approach is introduced to reason the spatial configuration of mechanisms in the conceptual design phase. Using the qualitative vector of fuzzy information, position vector, and qualitative constraint matrix, a reasoning structure for the spatial configuration of the mechanism is presented based on qualitative sign algebra. Assuming that complex mechanisms are composed of combinations of basic components, the reasoning structure is applied to reason about the spatial configuration of a complex mechanism. An analysis of the kinetics of the system is performed by reasoning with the vectors of basic components. An analysis of dynamic performance is presented.
Motion control and navigation of multiple mobile robots for obstacle avoidance and target seeking: A rule-based neuro-fuzzy technique
Authors: Pradhan S K , Parhi D R , Panda A K
Published: December 2008

This paper describes a rule-based neuro-fuzzy technique for the navigation of 1000 robots in a cluttered environment. The planning and coordination between the mobile robots is extremely difficult. In the present analysis rule-based and rule-based neuro-fuzzy techniques are used to navigate multiple mobile robots in unknown and partially known environments. The aim of the robots is to reach a predefined goal. Based upon a reference motion, direction, distances between the robots and obstacles, and distances between the robots and targets, different types of rules are defined heuristically and refined later to find the steering angle. The control system combines a repelling influence related to the distance between robots and nearby obstacles and an attracting influence between the robots and targets. Then a hybrid rule-based neuro-fuzzy technique is analysed to find the steering angle of the robots. Simulation and experimental results show that the proposed rule-based neuro-fuzzy technique shows a better navigation performance in complex and unknown environments than the simple rule-based technique.
The effect of niobium on the adhesive wear resistance of ferritic stainless steel
Authors: Aksoy M , Yilmaz S O , Evin E
Published: December 2008

The effects of Nb and homogenization heat treatment on the adhesive wear resistance of AISI 430 ferritic stainless steels containing 18 wt% Cr were investigated. The samples were cast as having additionally 0.5, 1.0, 1.5, and 3 wt% Nb. The samples were hot forged in the form of bars having 20 mm in diameters, and the samples were homogenized. The dry sliding wear tests were performed against AISI 1050 steel in a block-on-ring apparatus under the loads of 40, 60, and 80 N, respectively. The relations between wear rate, sliding distance, surface hardness, notch toughness, grain boundary energies, and friction coefficient were detected, and these relations were searched through metallographic investigations. Finally, it was seen that homogenization heat treatment reduced the total wear rate. The least wear rate was obtained from the homogenized sample having 0.5 wt% Nb in which niobium demonstrated a tendency to stabilize the cubic MX-type precipitates. A compatible relation between surface hardness, notch toughness, grain boundary energies, friction coefficient, and total wear rate was detected for homogenized samples.