bluuebunny/crossref_metadata_2025 huggingface dataset:
Close Approximation of Two Platelet Factor 4 Tetramers by Charge Neutralization Forms the Antigens Recognized by HIT Antibodies
Authors: Greinacher Andreas , Gopinadhan Manesh , Günther Jens-Uwe , Omer-Adam Mahmoud A. , Strobel Ulrike , Warkentin Theodore E. , Papastavrou Georg , Weitschies Werner , Helm Christiane A.
Published: July 2006

Objective—

Heparin-induced thrombocytopenia (HIT) is a prothrombotic drug reaction caused by antibodies that recognize positively charged platelet factor 4 (PF4), bound to the polyanion, heparin. The resulting immune complexes activate platelets. Unfractionated heparin (UFH) causes HIT more frequently than low-molecular-weight heparin (LMWH), whereas the smallest heparin-like molecule (the pentasaccharide, fondaparinux), induces anti-PF4/heparin antibodies as frequently as LMWH, but without exhibiting cross-reactivity with these antibodies. To better understand these findings, we analyzed the molecular structure of the complexes formed between PF4 and UFH, LMWH, or fondaparinux.

Methods and Results—

By atomic force microscopy and photon correlation spectroscopy, we show that with any of the 3 polyanions, but in the order, UFH>LMWH≫fondaparinux—PF4 forms clusters in which PF4 tetramers become closely apposed, and to which anti-PF4/heparin antibodies bind. By immunoassay, HIT antibodies bind strongly to PF4/H/PF4 complexes, but only weakly to single PF4/heparin molecules.

Conclusion—

HIT antigens are formed when charge neutralization by polyanion allows positively charged PF4 tetramers to undergo close approximation. Whereas such a model could explain why all 3 polyanions form antibodies with similar specificities, the striking differences in the relative size and amount of complexes formed likely correspond to the observed differences in immunogenicity (UFH>LMWH≈fondaparinux) and clinically relevant cross-reactivity (UFH>LMWH≫fondaparinux).
Glia Maturation Factor-γ Is Preferentially Expressed in Microvascular Endothelial and Inflammatory Cells and Modulates Actin Cytoskeleton Reorganization
Authors: Ikeda Koji , Kundu Ramendra K. , Ikeda Shoko , Kobara Miyuki , Matsubara Hiroaki , Quertermous Thomas
Published: July 2006

Actin cytoskeleton reorganization is a fundamental process for actin-based cellular functions such as cytokinesis, phagocytosis, and chemotaxis. Regulating actin cytoskeleton reorganization is therefore an attractive approach to control endothelial and inflammatory cells function and to treat cardiovascular diseases. Here, we identified glia maturation factor-γ (GMFG) as a novel factor in actin cytoskeleton reorganization and is expressed preferentially in microvascular endothelial and inflammatory cells. During mouse embryogenesis, GMFG was expressed predominantly in blood islands of the yolk sac, where endothelial and hematopoietic cells develop simultaneously. In endothelial cells, GMFG was colocalized with F-actin in membrane ruffles and was associated with F-actin assessed by actin co-sedimentation assay. Interestingly, GMFG was phosphorylated at N-terminal serine, and its phosphorylation was enhanced by coexpression of dominant active Rac1 and Cdc42. Furthermore, a pseudophosphorylated form of GMFG (GMFG-S2E) demonstrated higher association with F-actin. Stable expression of GMFG-S2E remarkably enhanced stimulus-responsive lamellipodia and subsequent membrane ruffle formation in HeLa cells presumably through its interaction with Arp2/3 complex. Expression of GMFG enhanced actin-based cellular functions such as migration and tube-formation in endothelial cells. Moreover, we found that GMFG expression was significantly increased in a cardiac ischemia/reperfusion model where inflammation and angiogenesis take place actively. Taken together, our findings define a novel pathway in the regulation of actin-based cellular functions. Regulating GMFG function may provide a novel approach to modulate the pathophysiology of cardiovascular diseases.
Aging Impairs the Beneficial Effect of Granulocyte Colony-Stimulating Factor and Stem Cell Factor on Post-Myocardial Infarction Remodeling
Authors: Lehrke Stephanie , Mazhari Ramesh , Durand Daniel J. , Zheng Meizi , Bedja Djahida , Zimmet Jeffrey M. , Schuleri Karl H. , Chi Andrew S. , Gabrielson Kathleen L. , Hare Joshua M.
Published: July 2006

Granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF) are potential new therapies to ameliorate post-myocardial infarction (post-MI) remodeling, as they enhance endogenous cardiac repair mechanisms and decrease cardiomyocyte apoptosis. Because both of these pathways undergo alterations with increasing age, we hypothesized that therapeutic efficacy of G-CSF and SCF is impaired in old versus young adult rats. MI was induced in 6- and 20-month-old rats by permanent ligation of the left coronary artery. In young animals, G-CSF/SCF therapy stabilized and reversed a decline in cardiac function, attenuated left ventricular dilation, decreased infarct size, and reduced cardiomyocyte hypertrophy. Remarkably, these effects on cardiac structure and function were absent in aged rodents. This could not be attributed to ineffective mobilization of bone marrow cells or decreased quantity of c-Kit
+
cells within the myocardium with aging. However, whereas the G-CSF/SCF cocktail reduced cardiac myocyte apoptosis in old as well as in young hearts, the degree of reduction was substantially less with age and the rate of cardiomyocyte apoptosis in old animals remained high despite cytokine treatment. These findings demonstrate that G-CSF/SCF lacks therapeutic efficacy in old animals by failing to offset periinfarct apoptosis and therefore raise important concerns regarding the efficacy of novel cytokine therapies in elderly individuals at greatest risk for adverse consequences of MI.
Peripheral Blood CD34
+
KDR
+
Endothelial Progenitor Cells Are Determinants of Subclinical Atherosclerosis in a Middle-Aged General Population
Authors: Fadini Gian Paolo , Coracina Anna , Baesso Ilenia , Agostini Carlo , Tiengo Antonio , Avogaro Angelo , Vigili de Kreutzenberg Saula
Published: July 2006

Background and Purpose—

Disruption of the endothelial layer is the first step in the atherogenic process. Experimental studies have shown that endothelial progenitor cells (EPCs) are involved in endothelial homeostasis and repair. Conversely, EPC depletion has been demonstrated in the setting of established atherosclerotic diseases. With this background, we evaluated whether variations in the number of EPCs are associated with subclinical atherosclerosis in healthy subjects.

Methods—

Carotid intima-media thickness (IMT), high-sensitive C-reactive protein (hsCRP), levels of circulating EPCs, and cardiovascular risk were compared in 137 healthy subjects. Six subpopulations of progenitor cells were determined by flow cytometry on the basis of the surface expression of CD34, CD133, and KDR antigens: CD34
+
, CD133
+
, CD34
+
CD133
+
, CD34
+
KDR
+
, CD133
+
KDR
+
, and CD34
+
CD133
+
KDR
+
.

Results—

Among different antigenic profiles of EPCs, only CD34
+
KDR
+
cells were significantly reduced in subjects with increased IMT. Specifically, CD34
+
KDR
+
cells were inversely correlated with IMT, even after adjustment for hsCRP and 10-year Framingham risk and independently of other cardiovascular parameters.

Conclusions—

Depletion of CD34
+
KDR
+
EPCs is an independent predictor of early subclinical atherosclerosis in healthy subjects and may provide additional information beyond classic risk factors and inflammatory markers.
Effect of the UK Incentive-Based Contract on the Management of Patients With Stroke in Primary Care
Authors: Simpson Colin R. , Hannaford Philip C. , Lefevre Karen , Williams David
Published: July 2006

Background and Purpose—

We wished to ascertain whether a new contract based on financial incentives for general practitioners has been associated with improved recording of quality indicators for patients with stroke and whether there was evidence of any difference in change between sex, age, and deprivation groups.

Methods—

In a serial cross-sectional study, patients from 310 general practices with a computer record of transient ischemic attack or stroke in Scotland were analyzed for their recording of quality indicators before and after the introduction of a new quality-based contract on March 31, 2004. Multivariate analyses were used to explore any differences in recording between age, sex, and deprivation groups.

Results—

Documentation of quality indicators increased over time, with absolute increases for individual indicators ranging from 32.3% to 52.1%. There was a large increase in the documentation of quality indicators among the oldest patients (>75 years) and the most affluent patients. This tended to attenuate age groups differences and to exacerbate differences between deprivation groups. Women tended to have larger increases in documentation than men; however, sex differences persisted, with women less likely than men to have smoking habits recorded (adjusted odds ratio, 0.87; 95% confidence interval, 0.81 to 0.95) or to receive antiplatelet or anticoagulant therapy (adjusted odds ratio, 0.93; 95% confidence interval, 0.86 to 0.99).

Conclusions—

The recording and management of quality indicators among patients with stroke increased substantially. However, inequitable care exists, which may have important implications for female, older, and more deprived subgroups in terms of stroke recurrence and mortality.
Distance Estimation in a Small-Scale Environment
Authors: Crompton Andrew , Brown Frank
Published: July 2006

In a test of cognitive distance perception participants estimated a walk in a picturesque village to be, on average, twice as long as an equal-length journey in a city. It is unlikely that any or all of the factors at present known to influence distance perception can account for such a large difference. A small correlation between estimate size and subject's height in the village but not the city suggests that distance estimates were based on different factors in the two places and that the scale of our interaction with our environment may influence our judgment of distance. It is hypothesized that small-scale places without cars may seem much larger than expected and that space may, so to speak, be made as if out of nothing by appropriate design.
Factors Influencing Owners' Reactions to Their Dogs' Fouling
Authors: Wells Deborah L.
Published: July 2006

This study explored what factors influence owners' reactions to their dogs'fouling in a bid to identify the demographic profile of the “typical” dog fouler. The behavior of 400 dog walkers was observed in eight public parks in Northern Ireland. Information was collected on the walkers' gender, age, socioeconomic status, use of leash, and reaction to their dogs' fouling. A weak majority (53.5%) of owners cleaned up their dogs'feces. All of the independent variables, except age, influenced owners' reactions to their pets' fouling. Fewer males (35.3%), those with a lower income (18.2%), and owners who allowed their dogs off the leash (26.2%) cleaned up their dogs'feces than females (58.2%), those with higher earnings (68.7%), and those who kept their pets on a leash (72.6%). Findings have implications for the design of antifouling campaigns, highlighting what sectors of the population need to be targeted by educational programs.
How Does Increasing Population and Diversity Affect Resident Satisfaction? A Small Community Case Study
Authors: Potter James , Cantarero Rodrigo
Published: July 2006

This study examines the quality of life in Crete, Nebraska, with the specific purpose of identifying the factors that play the largest role in determining residential satisfaction. The survey asks a number of questions pertaining to different aspects of living in Crete. The survey is adapted from a survey previously used for a similar study in Schuyler, Nebraska. Focus groups are used to identify key issues in Crete and make adjustments to the questionnaire. Cronbach's alpha is used to test the reliability of the topical variables, and index variables are created, which are used in the subsequent analysis. Using residential satisfaction as the dependent variable, stepwise multiple linear regressions are performed independently for the total population, the new arrivals, and the long-time resident groups. The findings of this study indicate that stressors and sociocultural issues are the significant contributors to the overall community's residential satisfaction.
Alternative Fuels in Transportation
Authors: Kouroussis Denis , Karimi Shahram
Published: July 2006

The realization of dwindling fossil fuel supplies and their adverse environmental impacts has accelerated research and development activities in the domain of renewable energy sources and technologies. Global energy demand is expected to rise during the next few decades, and the majority of today's energy is based on fossil fuels. Alternative energy sources and technologies can play a vital role in lowering or eliminating our reliance on fossil fuels. However, such a transition will require a large investment and will not be reversible. The benefits of hydrogen and other liquid fuels as transportation fuels are not marginal, but the real urgency in greenhouse gas reductions and fossil fuel replacement should not be translated into an energy infrastructure based on unsustainable sources in the long run. It is wise to examine each option thoroughly and objectively now and discard those with little potential so our focus and effort may be placed elsewhere.
The Hedonic and Utilitarian Dimensions of Attendees' Attitudes Toward Festivals
Authors: Gursoy Dogan , Spangenberg Eric R. , Rutherford Denney G.
Published: July 2006

This study examined the attendees'attitudes toward festivals by utilizing a two-dimensional consumer attitude scale, the Hedonic/Utilitarian (HED/UT) Scale, developed by Voss, Spangenberg, and Grohmann. The HED/UT Scale was originally developed to measure the hedonic and utilitarian dimensions of consumer attitudes toward product categories and different brands within categories. Findings suggested the scale has good reliability and validity and can be used successfully to measure attendees' attitudes toward festivals or other events and services. Results indicated that people attend festivals and other social events for both hedonic and utilitarian reasons. However, their hedonic attitudes have a stronger impact on attending the festival and other special events than their utilitarian attitude. Marketing and theoretical implications are discussed.
Rituximab maintenance improves clinical outcome of relapsed/resistant follicular non-Hodgkin lymphoma in patients both with and without rituximab during induction: results of a prospective randomized phase 3 intergroup trial
Authors: van Oers Marinus H. J. , Klasa Richard , Marcus Robert E. , Wolf Max , Kimby Eva , Gascoyne Randy D. , Jack Andrew , van't Veer Mars , Vranovsky Andrej , Holte Harald , van Glabbeke Martine , Teodorovic Ivana , Rozewicz Cynthia , Hagenbeek Anton
Published: July 2006

We evaluated the role of rituximab (R) both in remission induction and maintenance treatment of relapsed/resistant follicular lymphoma (FL). A total of 465 patients were randomized to induction with 6 cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) (every 3 weeks) or R-CHOP (R: 375 mg/m2 intravenously, day 1). Those in complete remission (CR) or partial remission (PR) were randomized to maintenance with R (375 mg/m2 intravenously once every 3 months for a maximum of 2 years) or observation. R-CHOP induction yielded an increased overall response rate (CHOP, 72.3%; R-CHOP, 85.1%; P < .001) and CR rate (CHOP, 15.6%; R-CHOP, 29.5%; P < .001). Median progression-free survival (PFS) from first randomization was 20.2 months after CHOP versus 33.1 months after R-CHOP (hazard ratio [HR], 0.65; P < .001). Rituximab maintenance yielded a median PFS from second randomization of 51.5 months versus 14.9 months with observation (HR, 0.40; P < .001). Improved PFS was found both after induction with CHOP (HR, 0.30; P < .001) and R-CHOP (HR, 0.54; P = .004). R maintenance also improved overall survival from second randomization: 85% at 3 years versus 77% with observation (HR, 0.52; P = .011). This is the first trial showing that in relapsed/resistant FL rituximab maintenance considerably improves PFS not only after CHOP but also after R-CHOP induction.
Randomized Phase II Trial of Letrozole and Letrozole Plus Low-Dose Metronomic Oral Cyclophosphamide As Primary Systemic Treatment in Elderly Breast Cancer Patients
Authors: Bottini Alberto , Generali Daniele , Brizzi Maria Pia , Fox Stephen B. , Bersiga Alessandra , Bonardi Simone , Allevi Giovanni , Aguggini Sergio , Bodini Giuliana , Milani Manuela , Dionisio Rossana , Bernardi Claudio , Montruccoli Arianna , Bruzzi Paolo , Harris Adrian L. , Dogliotti Luigi , Berruti Alfredo
Published: July 2006

Purpose

To investigate the activity of letrozole plus/minus oral metronomic cyclophophamide as primary systemic treatment (PST) in elderly breast cancer patients.

Methods

One hundred fourteen consecutive elderly women with T2-4 N0-1 and estrogen receptor–positive breast cancer were randomly assigned to primary letrozole therapy (2.5 mg daily for 6 months) or a combination of letrozole plus oral cyclophosphamide (50 mg/daily for 6 months) in an open-labeled, randomized phase II trial. Tumor response was assessed clinically, and tumor Ki67 index and vascular endothelial growth factor (VEGF) -A levels were measured before and after treatment.

Results

Overall response rate was 71.9% (95% CI, 60.0 to 83.8) in the 57 patients randomly assigned to receive primary letrozole and 87.7% (95% CI, 78.6 to 96.2) in the 57 patients randomly assigned to receive letrozole plus cyclophosphamide. The difference in activity between treatment arms was predominantly confined to patients with ductal histology. There was a significantly greater suppression of Ki67 and VEGF-A expression in the letrozole/cyclophosphamide-treated group than in the letrozole-treated group, leading to lower Ki67 and VEGF expression at post-treatment residual histology (P = .03 and P = .002, respectively).

Conclusion

Both letrozole and letrozole plus cyclophosphamide treatments appeared active as PST in elderly breast cancer patients. Metronomic scheduling of cyclophosphamide may have an antiangiogenetic effect and the combination of letrozole plus cyclophosphamide warrants testing in a randomized phase III trial.
Prospective Study of FGFR3 Mutations As a Prognostic Factor in Nonmuscle Invasive Urothelial Bladder Carcinomas
Authors: Hernández Silvia , López-Knowles Elena , Lloreta Josep , Kogevinas Manolis , Amorós Alex , Tardón Adonina , Carrato Alfredo , Serra Consol , Malats Núria , Real Francisco X.
Published: July 2006

Purpose

To determine the frequency and the prognostic value of fibroblast growth factor receptor 3 (FGFR3) mutations in patients with nonmuscle invasive bladder tumors according to tumor stage and grade.

Patients and Methods

Seven hundred seventy-two patients with newly diagnosed bladder tumors were recruited. Tumors were reviewed by expert pathologists. Patients were prospectively followed-up (median, 62.6 months for disease-free patients) through review of hospital records and telephone interviews. The sequence of exons 7 and 10 of FGFR3 was analyzed by polymerase chain reaction and direct sequencing. We assessed the association of mutations with stage and grade. The predictive value of mutations for recurrence, progression, and mortality were assessed using Kaplan-Meier and Cox multivariable models.

Results

Mutations were more common among low malignant potential neoplasms (LMPN; 77%) and TaG1/TaG2 tumors (61%/58%) than among TaG3 tumors (34%) and T1G3 tumors (17%). The S249C, Y375C, S248C, and G372C mutations accounted for 91.5% of all sequence changes. The A393E substitution was associated with LMPN (P < .001). The F386L polymorphism was more frequent among patients with low-grade tumors (odds ratio, 6.97; 95%CI, 1.40 to 47.06; P = .009). In the multivariable analysis of all superficial tumors, mutations were associated with increased risk of recurrence. However, in the stratified analyses only patients with TaG1 tumors had a significantly higher risk of recurrence (hazard ratio, 2.12; 95%CI, 1.28 to 3.53; P = .004).

Conclusion

The findings of this large study strongly support the notion that FGFR3 mutations characterize a subgroup of bladder cancers with good prognosis; patients with mutant TaG1 tumors have a higher risk of recurrence; and the F386L variant is selectively associated with low-grade tumors.
Health Status Measurements at Diagnosis As Predictors of Survival Among Adults With Brain Tumors
Authors: McCarter Helen , Furlong William , Whitton Anthony C. , Feeny David , DePauw Sonja , Willan Andrew R. , Barr Ronald D.
Published: July 2006

Purpose

The intent of this study was to determine whether baseline measures of functional capacity and performance could be used to predict survival in adults following the diagnosis of brain tumors.

Patients and Methods

Comprehensive health status and health-related quality of life (HRQL) were measured using the Health Utilities Index (HUI; McMaster University, Hamilton, Canada) system by a self-assessment questionnaire in a survey of 100 consecutive patients. The Karnofsky Performance Score (KPS) and Folstein's Mini-Mental State Examination (MMSE) scores were measured by a physician blinded to the HUI results. The patients were observed for up to 5 years to recorded dates of death.

Results

An HUI questionnaire was completed for 93% of the patients and 69% died within 5 years of assessment. The HUI revealed a burden of morbidity and complexity of disability that far exceeded that reported for the general population. KPS and MMSE correlated strongly with each other (r = 0.52; P < .001). A decrease of 0.1 units in HUI Mark 2 (HUI2) self-care single-attribute utility score was associated with an increased hazard of death of 30% (P = .023) for patients with low-grade tumors (n=25). For patients with high-grade tumors (n=56), a 10 unit decrease in the KPS, a 5 unit decrease in MMSE, and a 0.1 decrease in HUI Mark 3 (HUI3) speech and dexterity single-attribute scores were associated with an increased hazard of death of 20% (P = .022), 26% (P = .015), 36% (P = .021), and 18% (P = .035), respectively.

Conclusion

Scores derived from the measurement of HRQL following diagnosis can predict survival in adults with brain tumors.
Phase III Trial Comparing 4-Day Chronomodulated Therapy Versus 2-Day Conventional Delivery of Fluorouracil, Leucovorin, and Oxaliplatin As First-Line Chemotherapy of Metastatic Colorectal Cancer: The European Organisation for Research and Treatment of Cancer Chronotherapy Group
Authors: Giacchetti Sylvie , Bjarnason Georg , Garufi Carlo , Genet Dominique , Iacobelli Stefano , Tampellini Marco , Smaaland Rune , Focan Christian , Coudert Bruno , Humblet Yves , Canon Jean Luc , Adenis Antoine , Re Giovanni Lo , Carvalho Carlos , Schueller Johannes , Anciaux Nicole , Lentz Marie-Ange , Baron Benoît , Gorlia Thierry , Lévi Francis
Published: July 2006

Purpose

In two previous randomized trials, the adjustment of chemotherapy delivery to circadian rhythms improved tolerability and anticancer activity compared with constant-rate infusion during 5 days in patients with metastatic colorectal cancer.

Patients and Methods

For this multicenter randomized trial, it was hypothesized that a chronomodulated infusion of fluorouracil, leucovorin, and oxaliplatin for 4 days (chronoFLO4) would improve survival by 10% compared with conventional 2-day delivery of the same drugs (FOLFOX2). Patients were treated every 2 weeks with intrapatient dose escalation.

Results

Baseline characteristics were similar in both arms for the 564 patients (36 institutions, 10 countries). Median survival was 19.6 months (95% confidence limit [CL] = 18.2, 21.2) with chronoFLO4 and 18.7 months with FOLFOX2 (95% CL = 17.7, 21.0; P = .55). The main dose-limiting toxicities were diarrhea for chronoFLO4 and neutropenia for FOLFOX2. The analysis of survival predictors showed that sex was the single most important factor (P = .001). In women, the risk of an earlier death with chronoFLO4 was increased by 38% compared with FOLFOX2, with median survival times of 16.3 and 19.1 months (P = .03), respectively. In men, the risk of death was decreased by 25% with chronoFLO4 compared with FOLFOX2, with median survival times of 21.4 and 18.3 months (P = .02), respectively.

Conclusion

Both regimens achieved similar median survival times more than 18 months with an acceptable toxicity. The chronomodulated schedule produced a survival advantage over FOLFOX in men. The strong sex dependency of optimal scheduling of fluorouracil, leucovorin, and oxaliplatin calls for translational investigations of determinants related to the patient's molecular clock.
Relaxin Is Essential for Systemic Vasodilation and Increased Global Arterial Compliance during Early Pregnancy in Conscious Rats
Authors: Debrah Dan O. , Novak Jackie , Matthews Julianna E. , Ramirez Rolando J. , Shroff Sanjeev G. , Conrad Kirk P.
Published: July 2006

During early pregnancy, there are marked increases in cardiac output (CO) and global arterial compliance (AC), as well as decreases in systemic vascular resistance (SVR). We recently reported that administration of recombinant human relaxin to nonpregnant female rats elicits changes in systemic hemodynamics and arterial mechanical properties similar to those observed during normal pregnancy. In the present study, we directly tested whether endogenous relaxin mediates the cardiovascular adaptations of pregnancy by neutralizing circulating relaxin with monoclonal antibodies during early gestation. Relaxin neutralizing antibodies were administered daily, beginning on d 8 of rat gestation, to block the functional effects of circulating relaxin. Systemic hemodynamics and arterial properties were assessed between gestational d 11 and 15 using techniques we have previously reported. Pregnant rats administered the neutralizing antibodies failed to exhibit the gestational increases in stroke volume, CO, and global AC or decreases in SVR that were observed in control pregnant rats administered an irrelevant antibody against fluorescein or PBS. In fact, in the pregnant rats administered the relaxin neutralizing antibodies, cardiovascular parameters were not statistically different from those in virgin rats. Interestingly, small renal and first-order mesenteric arteries isolated from midterm pregnant rats administered either relaxin-neutralizing or control antibodies did not exhibit any changes in passive mechanical properties compared with virgin rats. These findings indicate that circulating relaxin mediates the transition of the systemic circulation from the virgin to the pregnant state in the gravid rat model, suggesting a potential role for aberrant relaxin regulation in abnormal pregnancies wherein these cardiovascular adaptations are inadequate or excessive.
Influence of Coating-Substrate Systems on Chip and Burr Formation in Precision Manufacturing
Authors: Leopold J , Neugebauer R , Löffler M , Schwenck M , Hänle P
Published: July 2006

Higher precision of manufactured parts and surfaces, reduction of processing time with simultaneous increase of tool life and fully automated production are the major aims of research and development in the field of cutting. In order to fulfil the high demands and, in addition, to ensure a high process reliability, new methods for theoretical investigations are required. However, the continuous development of new cutting tools with a complex microgeometry, covered with improved coatings and applied to manufacturing of advanced materials requires high-resolution simulation and non-linear methods. This paper deals with new investigations based on the finite element method (FEM). Burr formation has been investigated with finite element (FE) and also experimentally and the influence of coating-substrate systems will be pointed out.
Surface and Edge Quality Variation in Precision Machining of Single Crystal and Polycrystalline Materials
Authors: Min S , Lee D-E , de Grave A , De Oliveira Valente C M , Lin J , Dornfeld D A
Published: July 2006

The surface and edge quality of single-crystal and polycrystalline copper workpieces has been observed to vary significantly as a function of crystallographic orientation. On the precision scale, the chip formation process is influenced by the microstructure of the material, such as grain boundaries and grain orientation in polycrystalline materials, and crystallographic orientation in single-crystal materials. Such variation in the microstructure has a significant effect on the resulting surface, edge, and burr topography.
Contact Modelling in Resistance Welding. Part 1: Algorithms and Numerical Verification
Authors: Song Quanfeng , Zhang Wenqi , Bay Niels
Published: July 2006

Finite element based numerical modelling programs for resistance welding are presently being improved as an important tool for development and optimization of complex joints. One of the remaining challenges in obtaining useful results is appropriate modelling of the contact between the parts. The contact problem in resistance welding includes not only mechanical contact but also thermal and electrical contact. In this paper such a contact model is developed for simulation of resistance spot and projection welding. The mechanical contact includes frictionless contact as well as contact with sticking and with sliding friction. The thermal and the electrical contact are modelled by introducing an artificial contact layer. After a description of the algorithms, several numerical examples are presented to validate the mechanical contact algorithm.
Contact Modelling in Resistance Welding. Part 2: Experimental Validation
Authors: Song Quanfeng , Zhang Wenqi , Bay Niels
Published: July 2006

Contact algorithms in resistance welding presented in the previous paper are experimentally validated in the present paper. In order to verify the mechanical contact algorithm, two types of experiment, i.e. sandwich upsetting of circular, cylindrical specimens and compression tests of discs with a solid ring projection towards a flat ring, are carried out at room temperature. The complete algorithm, involving not only the mechanical model but also the thermal and electrical models, is validated by projection welding experiments. The experimental results are in good agreement with the simulation prediction, showing the validity of the algorithm.
Integration of Tool Geometry in Prediction of Cutting Forces During Milling of Hard Materials
Authors: Bissey-Breton S , Poulachon G , Lapujoulade F
Published: July 2006

Knowledge of the cutting forces owing to a predictive model is very interesting with respect to the choice of a machine tool power, the cutting tools, the optimization of cutting conditions for a given machining operation or the control of the occurrence of vibrations. It could also be helpful in online wear monitoring during milling. As this technique is usually based on a limit level of the cutting forces, it could allow the number of long and expensive tests to be limited and the best tool geometry to obtain quasi-constant and low cutting forces, which lead to a reduced tool wear, and consequently, a better tool-life, to be found. The objective of this study is the prediction of the effects of the rake and helix angles on the cutting force variations, and to integrate it into a cutting relation. Tests were made on X38 CrMoV 5 (AISI H11) die and mould steel, with solid carbide milling cutters of various rake angles. A specific configuration has been used to create obliquity. Cutting forces were measured for various feed rates. The results have improved the cutting force model, making it possible to choose the optimal rake and helix angles in a particular machining operation.
Friction Stir Welding of AA6082-T6 T-joints: Process Engineering and Performance Measurement
Authors: Fratini L , Buffa G , Filice L , Gagliardi F
Published: July 2006

In the paper the authors present the results of a wide range of experiments on T-parts. First, friction stir welding process engineering has been developed with the aim of determining the specific process parameters that make up the soundness of the obtained T-parts. Then the performance of the obtained T-joints has been compared with T-joints obtained by metal inert gas welding and extruded T-parts. The parts have been tested utilizing a customized bending test with the aim of highlighting their behaviour both in elastic and plastic fields.
An Investigation of Tool Chip Contact Phenomena in High-Speed Turning Using Coated Tools
Authors: Mativenga P T , Abukhshim N A , Sheikh M A , Hon B K K
Published: July 2006

This paper focuses on the investigation of contact length and chip morphology in high-speed turning. In this study the performance of five different coatings: TiN, TiCN, TiAlN and CrTiAlN PVD coatings, and an advanced Dymon-IC hydrogenated amorphous carbonbased coating (a-C:H) deposited by plasma-enhanced chemical vapour deposition (PECVD) is investigated in high-speed machining (HSM) of AISI/SAE - 4140 high-strength alloy steel at cutting speeds ranging between 210 and 925 m/min. Modelling of chip contact length is revisited and the results of extensive machining tests supported by use of a high-speed camera are reported. The effects of coatings on the chip compression ratio, back flow angle, tool-chip contact length, frictional force, and tool wear are explored. The paper contributes towards a fundamental understanding of heat generation and partition in metal cutting using coated tools.
A knowledge-Based Infotronics Supervisory System for Intelligent Service Automation
Authors: Wang W M , Cheung C F , Lee W B , Kwok S K
Published: July 2006

With the effect of globalization, today's physical asset management (PAM) activities are becoming more and more complex and it is essential to make optimal use of knowledge of PAM. However, conventional methods of PAM relying on condition-based maintenance are inadequate to attain the multi-perspective of an enterprise for accomplishing knowledge management, proactive maintenance planning, and intelligent service automation in order to drive the continuous improvement of the enterprise. This paper presents a knowledge-based infotronics supervisory system (KISS) that integrates Infotronics, automatic supervision, and multi-agent and various artificial intelligence technologies to achieve these purposes. A prototype system has been built and evaluated through a trial implementation in a semiconductor industry.
Statistical Characteristic for Detecting Weld Penetration Defects in Gas-Metal Arc Welding
Authors: Wu C S , Jia C B
Published: July 2006

In robotic arc welding, many disturbances often result in weld defects, such as incomplete penetration and burn-through. The development of an intelligent monitoring system for weld defects in real time during the robotic arc welding process is of great significance. In this paper, robotics-based gas-metal arc welding experiments are carried out on the mild steel testpieces with ‘V’-type groove. Two disturbances are intentionally introduced to produce two kinds of weld penetration defect, i.e. incomplete penetration and burn-through. A through-the-arc sensing method is used to capture the transient values of the welding voltage and current. The raw data of the captured welding current and voltage are processed, and the statistical characteristic M10 is extracted to correlate the welding conditions to the weld penetration information. This lays the foundation for intelligent monitoring of weld quality in robotic arc welding.
Data Management in Small and Medium-Sized Enterprises Using Metadata Acquired by ‘Spyware’
Authors: Aitchison D R , Shaw A I
Published: July 2006

Data generated during a product development process are increasingly created and communicated using a digital format. Management of these data can be a key enabler of the design process; strategic, tactical, and operational management of the data can lead to shorter product development timeframes and hence competitive advantage in the marketplace. While larger companies have both the infrastructure and resources to implement sophisticated software to manage the myriad of data created, small and medium-sized enterprises (SMEs), owing to their inherent characteristics, lag in the adoption of data management tools. This paper describes research using so-called ‘Spyware’ software and reports how this software is used in a novel methodology to develop information management functions for SMEs.
A Cost-Effective Knowledge-Based Reasoning System for Design for Automation
Authors: Shehab E M , Abdalla H S
Published: July 2006

Design for assembly automation (DFAA) is an important part of the concurrent engineering strategy for reduction of product manufacturing costs and lead times. An intelligent knowledge-based system (KBS) for design for automation and early cost modelling within a concurrent engineering environment has been developed. This paper focuses upon the development of the design for an assembly automation system. The system framework encompasses an extensive knowledge-based reasoning system, a CAD system, a design analysis for automation module, a design improvement suggestion module, and a user interface. The development process of the system involved three main stages: creating the KBS, developing the design improvement module, and integrating the KBS with the CAD system. The developed system has the capability to: (a) select the most economic assembly technique for the product at an early design stage; (b) estimate the assembly time and cost for manual, automatic, and robotic assembly methods; and (c) analyse the product design for automation and provide the designers with design improvement suggestions of a product to simplify assembly operations without any compromise of the product functionality. The above capabilities of the system have been demonstrated and validated through a real case study.
Kelvin - Helmholtz and Streamwise Vortices in the Near Wake of a Single-Lobe Forced Mixer
Authors: Mao R H , Yu S C M , Chua L P
Published: July 2006

In the present experimental investigation, the characteristics of two types of vortices, namely the normal Kelvin-Helmholtz (K-H) and streamwise vortices, generated in the near wake of a lobed forced mixer were examined and evaluated at two velocity ratios (r = U1: U2 = 1:1 and 0.4:1). The lobed forced mixer has only one lobe and was designed to eliminate any possible interactions between the neighbouring vortices generated by the adjacent lobes. Hot-wire anemometer was used to study the K-H vortices via the spectrum analysis. Laser-Doppler anemometer was employed to examine the streamwise vortices. It was found that there were two main frequencies for the K-H vortex in the wake of the forced mixer ( fLM_C and fLM_L); both were higher than the case of plane-free shear layer ( fFP), i.e., fLM_C fLM_L fFP. where fLM_C represents the K-H vortex shedding frequency in the behind the semi-circle part of the trailing edge, whereas fLM_L represents the frequency in the near wake behind the parallel side-walls of the trailing edge. The velocity ratio appeared to have more important effects at point C than at point L. The Strouhal numbers ( StLM_C and StLM_L) reached constant values at the Reynolds number greater than 5 × 105. The K-H vorticities for the velocity ratio r= 0.4 was ∼30 and 110 per cent stronger than for case r= 1 for points L and C, respectively. The K-H vortices were also found to be more contributive to the production of the turbulent kinetic energy in the near wake of the single-lobe forced mixer than the streamwise vortices. The streamwise vortices at r= 0.4 accelerated the breakdown of the K-H vortices, which happened at about one wavelength earlier than r= 1. Finally, the effects of geometry parameters, including lobe height (or penetration angle) and wavelength, were examined.
Vorticity and Circulation Aspects of Twin Jets in Cross-Flow for an Oblique Nozzle Arrangement
Authors: Kolář V , Savory E , Takao H , Todoroki T , Okamoto S , Toy N
Published: July 2006

The ‘jet in cross-flow’ (JICF) phenomenon, in which a single jet issues normally into a cross-flow through a circular nozzle, is an aspect of many aerodynamic applications and is related to the effectiveness of both propulsion and control systems. In many instances, such applications involve two or more jets that may interact with each other as they develop in the downstream direction. By considering an oblique nozzle ground arrangement, the present experimental work extends the previous results that the authors have obtained for ‘twin JICF’ (TJICF) concerning two geometrically symmetric TJICF arrangements, namely tandem and side-by-side nozzle configurations. The work concentrates on the vorticity distribution and overall circulation associated with the dominant vortical structure of the TJICF, rather similar to that of the well-known contrarotating vortex pair of the single JICF.
Square Deployable Frames for Space Applications. Part 1: Theory
Authors: Chen Y , You Z
Published: July 2006

The Bennett linkage is a three-dimensional 4R overconstrained mechanism consisting of four rigid links connected by revolute hinges whose axes of rotation are neither parallel nor concurrent. In general, it cannot be folded up compactly. This paper investigates the existence of alternative forms of the linkage in order to achieve the most compact folding and maximum expansion so that the linkage can be used as basic building blocks of large deployable structures for aerospace applications. This study has resulted in the creation of an effective deployable element based on the Bennett linkage. A simple method to build the Bennett linkage in its alternative form has been introduced and verified. The corresponding networks have been obtained following a layout similar to that the original Bennett linkage, which the authors discovered previously. This approach can also be extended to other types of overconstrained linkages so that they can be used for building large deployable assemblies as well.
Preparation and Thermal Evolution of Sol–Gel Derived Zirconia and Ceria–Zirconia Precursors
Authors: Settu T , Gobinathan R
Published: July 2006

Precursor powders of pure and 10 mol% ceria doped zirconia have been prepared by physical gelation of zirconium(IV) dichloride oxide, cerium nitrate, and oxalic acid using triple distilled water as solvent at room temperature (ca. 27 °C). Both the zirconium(IV) and doped zirconium(IV) oxalate oxide gels are transparent and are dried at 40 °C. The thermal evolution and crystallization behaviors of the amorphous gels have been investigated by TGA, DTA, and X-ray diffraction analysis. On calcination at 850 °C, zirconia precursor transformed to a monoclinic phase whereas only tetragonal phase has been observed for doped zirconia precursor. Estimation of the surface area and IR characterization have also been carried out for the prepared dried powders.
Efficient Hydroxyl Radical Production and Their Reactivity with Ethanol in the Presence of Photoexcited Semiconductors
Authors: Noda Hiroyuki , Oikawa Kazuo , Ohya-Nishiguchi Hiroaki , Kamada Hitoshi
Published: July 2006

ESR spin trapping technique has been applied to determine the quantum efficiency of the hydroxyl radical production from semiconductors such as anatase and rutile TiO2, WO3, and ZnO photoexcited with a 365 nm UV lamp in water and aqueous H2O2 solution. The quantum efficiency for anatase TiO2, rutile TiO2, and WO3 in H2O2 solution was 3—4 times larger than that in water. Its maximum values, 4.6% in water and 14.8% in 1 mmol dm−3 H2O2 solution were obtained from anatase TiO2. The reaction of the hydroxyl radical from photoexcited semiconductors with ethanol has been investigated in relation to the C-centered radical production in aqueous ethanol solution. The possible photocatalytic redox mechanisms are discussed concerning the reactions caused by photoinduced electron-hole pairs and produced radicals.
Vibronic Analysis of the ca. 400 nm Band of the Phenoxy Radical within the Approximation of the Weak Coupling Limit
Authors: Takahashi Junko , Shida Tadamasa
Published: July 2006

The effect of vibronic coupling on the absorption band at ca. 400 nm as well as on the Raman spectrum of the phenoxy radical (The IUPAC nomenclature recommends phenoxyl. However, in spectroscopic studies most authors prefer phenoxy to phenoxyl.) is examined by ab initio MO calculations within the framework of the adiabatic approximation. The vibronic coupling effect is represented in terms of the linear non-Condon term in the analysis of the absorption band and in terms of the B-term in the Raman study. The inclusion of the coupling effect improves theoretical spectra fits to experimental spectra.
Electric Conductivity Analysis of Micellar Solution of Sodium Dodecyl Sulfate
Authors: Moroi Yoshikiyo , Matsuoka Keisuke
Published: July 2006

Electric conductivities at 298.2 K of sodium dodecyl sulfate solution above the cmc were analyzed from the concentrations of counterion, surfactant ion, and micelle based upon the mass action model of monodisperse micelle formation, where the three micellization parameters (log Kn = 230, n = 64, and m = 46.7) were employed. The ionic conductivity of micelle was found to be inconsistent not only with the micellar size of the identical charge but also with the conductivity of the dynamic radius of micelle of the identical charge. The inconsistencies could be solved by the hopping reaction of counterions between micelles through the overlapping of ionic diffuse double layers around micelle that takes place when two micelles come close together. The hopping reaction was found to start when the distance between micelles becomes less than 5 times the Debye length.
Solvent Extraction of Lanthanoids(III) and Yttrium(III) with N-Alkylcarbonyl-N-(4-chlorophenyl)hydroxylamines
Authors: Saitoh Tohru , Okuyama Manabu , Minagawa Madoka , Kamidate Tamio , Watanabe Hiroto , Haraguchi Kensaku
Published: July 2006

We investigated the effect of halogen substitution of N-alkylcarbonyl-N-phenylhydroxylamines on the extraction of lanthanoids(III). A p-chloro substituent of a phenyl group increased the acidity of R-PHAs by 0.3—0.5 pKa units, and a bromo substituent on the α carbon of the acyl group increased it by 1.5 pKa units. In the former substitution, the separation factor for pairs of lanthanoids(III) and yttrium(III) remained unchanged, whereas in the latter the separation factor was considerably reduced. Hence, the chloro substitution at the phenyl group was a good choice for lowering pH values in the extraction of lanthanoids(III). The pH region was suitable for extracting lanthanoids(III) while preventing the formation of their hydroxo complexes.
Volume Changes on the Conversion from Quinquedentate EDTA Complexes of Co(III) and Cr(III) into Sexidentate Complexes
Authors: Yoshitani Kouzou
Published: July 2006

For the conversion from quinquedentate complexes, [Co(edtaH)(H2O)] and [Co(edta)(H2O)]−, into the sexidentate complex, [Co(edta)]−, the respective volume changes were measured from the density data at 25 °C. The volume change was determined as well for the proton dissociation of [Cr(edtaH)(H2O)]. A comparison of the volume changes in the Co(III) system with the corresponding Cr(III) system supports the recent view that edta forms a sexidentate complex with Cr(III) in the pH 3.5—6.5 range.