bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of a Health Behavior Change Model—Based HIV/STI Prevention Intervention on Condom Use Among Heterosexual Couples: A Randomized Trial
Authors: Harvey S. Marie , Kraft Joan Marie , West Stephen G. , Taylor Aaron B. , Pappas-DeLuca Katina A. , Beckman Linda J.
Published: September 2008

This study examines an intervention for heterosexual couples to prevent human immunodeficiency virus/sexually transmitted infections. It also evaluates the effect of the intervention, which is based on current models of health behavior change, on intermediate outcomes (individual and relationship factors) and consistency of condom use. Eligible couples were administered a baseline interview and randomized to either a 3-session theory-based intervention or a 1-session standard of care comparison condition. Men and women completed 3-month interviews; only women completed 6-month interviews. No significant intervention effect on condom use was found among couples at 3 months ( n = 212) or among women ( n = 178) at 6 months. However, condom use increased significantly between baseline and 3 months and baseline and 6 months for participants in both treatment conditions. Intervention effects on condom use self-efficacy were found at 3 months and 6 months and on health-protective communication at 3 months. These findings provide valuable information for the design of future studies to help disentangle the effects of intervening with couples.
Communicative Reason and Intercultural Understanding
Authors: Czobor-Lupp Mihaela
Published: September 2008

Although Habermas sees intercultural understanding as a political task, his model of communicative rationality cannot satisfactorily explain how this could happen. One reason is the definition of the aesthetic, form-giving, moment of imagination, which reflects deeper epistemological and linguistic assumptions of discourse ethics. Despite sporadic attempts to recognize the role of rhetoric and poetry as an indispensable part of the communicative praxis, at the end of the day, Habermas sees language as fundamentally geared toward transparency and clarity, and not as endowed with poetic power and polyphonic creativity. My article aims to further develop, with the help of Vico and Bakhtin, the incipient thread in Habermas's discourse ethics that recognizes the importance of linguistic creativity and of imagination in communicative practice. This would help one to argue that, even when rational consensus and agreement cannot be achieved, dialogue is still not abandoned. This is the case because, through a larger definition of the dialogical, which adds to the discursive aspect, an aesthetic, rhetorical, and metaphorical dimension, it is possible to say that, even when conflicting, different voices and languages are still creatively and imaginatively interilluminating and hybridizing each other. Thus, they still transform each other, creating, at the same time, a prediscursive commonality, that can function as a necessary prerequisite for intercultural understanding.
young children's musical worlds
Authors: Lamont Alexandra
Published: September 2008

This study explores preschoolers' real life engagement with music in everyday life, examining the choices that they have over music listening and the engagement that they show in relation to music in different contexts. A total of 32 children from the United Kingdom aged 3.2—3.9 years participated with their families, nursery teachers and other caregivers. Experience sampling methodology was used to capture up to 21 episodes within a seven-day period. A total of 437 episodes were captured, and 81% had music exposure, either at the time of the call (38%) or during the two preceding hours (43%). Children's music was most frequently heard and chosen by the children themselves; pop music was also frequently heard but less often chosen by the children. The roles of choice, format, focus and style in understanding children's early music listening behaviours and motivations are carefully analysed.
teacher inquiries into gay and lesbian families in early childhood classrooms
Authors: Souto-Manning Mariana , Hermann-Wilmarth Jill
Published: September 2008

Gay and lesbian issues are often silenced in teacher education programs. Such silencing has serious consequences for teachers who feel unprepared to discuss such issues in their classrooms. Challenging the silence regarding gay and lesbian issues that often permeates early childhood classrooms, we share a teacher's critical inquiry into teaching gay and lesbian issues through teacher action research. We posit that while gay and lesbian issues need to be an intrinsic part of teacher education classes, practising teachers may create the opportunity to take steps toward addressing diversity, fully including gay and lesbian issues in their classrooms. We propose that the case presented may provide a practical possibility for teachers to find ways to fully include all students in their literacy practices.
NK cell–activating receptors require PKC-θ for sustained signaling, transcriptional activation, and IFN-γ secretion
Authors: Tassi Ilaria , Cella Marina , Presti Rachel , Colucci Angela , Gilfillan Susan , Littman Dan R. , Colonna Marco
Published: September 2008

Natural killer (NK) cell sense virally infected cells and tumor cells through multiple cell surface receptors. Many NK cell–activating receptors signal through immunoreceptor tyrosine–based activation motif (ITAM)–containing adapters, which trigger both cytotoxicy and secretion of interferon-gamma (IFN-γ). Within the ITAM pathway, distinct signaling intermediates are variably involved in cytotoxicity and/or IFN-γ secretion. In this study, we have evaluated the role of protein kinase C-θ (PKC-θ) in NK-cell secretion of lytic mediators and IFN-γ. We found that engagement of NK-cell receptors that signal through ITAMs results in prompt activation of PKC-θ. Analyses of NK cells from PKC-θ–deficient mice indicated that PKC-θ is absolutely required for ITAM-mediated IFN-γ secretion, whereas it has no marked influence on the release of cytolytic mediators. Moreover, we found that PKC-θ deficiency preferentially impairs sustained extracellular-regulated kinase signaling as well as activation of c-Jun N-terminal kinase and the transcription factors AP-1 and NFAT but does not affect activation of NF-κB. These results indicate that NK cell–activating receptors require PKC-θ to generate sustained intracellular signals that reach the nucleus and promote transcriptional activation, ultimately inducing IFN-γ production.
Mechanisms and pathologic significances in increase in serum interleukin-6 (IL-6) and soluble IL-6 receptor after administration of an anti–IL-6 receptor antibody, tocilizumab, in patients with rheumatoid arthritis and Castleman disease
Authors: Nishimoto Norihiro , Terao Kimio , Mima Toru , Nakahara Hideko , Takagi Nobuhiro , Kakehi Takahiro
Published: September 2008

Interleukin-6 (IL-6) plays pathologic roles in immune-inflammatory diseases such as rheumatoid arthritis (RA) and Castleman disease. By inhibiting IL-6 receptors (IL-6Rs), tocilizumab (a humanized anti–IL-6R antibody) ameliorates the symptoms of these diseases and normalizes acute-phase proteins, including C-reactive protein (CRP). We found that tocilizumab treatment increased serum levels of IL-6 and soluble IL-6R (sIL-6R). To investigate the pathologic significance of these increases, we analyzed the kinetics of serum IL-6 and sIL-6R and the proportion of sIL-6R saturated with tocilizumab after tocilizumab administration in patients with RA and Castleman disease and then compared the results with the CRP values. Serum IL-6 and sIL-6R markedly increased after tocilizumab administration in both RA and Castleman disease. As long as free tocilizumab was detectable, sIL-6R was saturated with tocilizumab and IL-6 signaling was completely inhibited. We concluded that it is likely that sIL-6R increased because its elimination half-life was prolonged by the formation of tocilizumab/sIL-6R immune complex, and that free serum IL-6 increased because IL-6R–mediated consumption of IL-6 was inhibited by the unavailability of tocilizumab-free IL-6R. We also concluded that the increased level of free IL-6 during tocilizumab treatment closely reflects the actual endogenous IL-6 production and true disease activity.
CD4+ T lymphocytes mediate in vivo clearance of plasmid DNA vaccine antigen expression and potentiate CD8+ T-cell immune responses
Authors: Geiben-Lynn Ralf , Greenland John R. , Frimpong-Boateng Kwesi , van Rooijen Nico , Hovav Avi-Hai , Letvin Norman L.
Published: September 2008

There is evidence that the limited immunogenicity of plasmid DNA vaccines is the result, at least in part, of the rapid clearance of vaccine antigen expression by antigen-specific immune responses. However, the cell types responsible for the clearance of plasmid DNA vaccine antigens are not known. Here we demonstrate that macrophages, NK cells, and CD8+ T cells did not significantly contribute to the DNA antigen clearance but CD4+ T cells played the crucial role in attenuating plasmid DNA vaccine antigen expression. Adoptive transfer experiments demonstrate that CD4+ T cells facilitated DNA vaccine antigen clearance in a Fas/FasL-dependent manner. Furthermore, we show that depletion of CD4+ T cells prevented the clearance of vaccine antigen and the appearance of a CD8+ T-cell immune response. Inoculation of major histocompatibility complex class II KO mice with the plasmid DNA led to persistent antigen expression and abolition of a CD8+ T-cell immune response. Importantly, the prolongation of antigen expression by disrupting the CD4+ T-cell Fas/FasL myocytes signaling led to a 3- to 5-fold increase of antigen-specific CD8+ T-cell responses. These data demonstrate a dominant role of CD4+ T cell–mediated cytotoxicity in plasmid DNA vaccine antigen clearance.
Evaluating score distributions in the revised Dutch version of the Childhood Health Assessment Questionnaire
Authors: Ouwerkerk Jessika W , van Pelt Philomine A , Takken Tim , Helders Paul JM , Net Janjaap van der
Published: September 2008

Objectives

Evaluating the original, and the revised version of the Dutch Childhood Health Assessment Questionnaire (CHAQ). To explore the effect of different score calculation methods and eight more challenging items as proposed by Lam et al. (2004) on the score distribution in a population of patients with Juvenile Idiopathic Arthritis (JIA).

Methods

Two convenience samples of 59 and 31 children with JIA were studied. Box-and-whisker plots and the Kolmogorov-Smirnov (K-S) one-sample test of normality were used, to explore the score distributions.

Results

The results of this study confirm a ceiling effect when using the original CHAQ-30 with either score calculation method. The original CHAQ with the added eight more challenging items and the "mean" score calculation method, as well as the revised CHAQ showed less ceiling effect.

Conclusion

The original CHAQ-38 with the "mean" score calculation method as well as the revised CHAQ are a possible alternative for future studies. However, there is a need for further prospective studies to improve the CHAQ and to support our findings.
Expression of CD74 is increased in neurofibrillary tangles in Alzheimer's disease
Authors: Bryan Kathryn J , Zhu Xiongwei , Harris Peggy L , Perry George , Castellani Rudy J , Smith Mark A , Casadesus Gemma
Published: September 2008

Alzheimer disease (AD) is a chronic neurodegenerative disease that is characterized by progressive memory loss. Pathological markers of AD include neurofibrillary tangles, accumulation of amyloid-β plaques, neuronal loss, and inflammation. The exact events that lead to the neuronal dysfunction and loss are not completely understood. However, pro-inflammatory cytokines, such as interleukin-1β, interleukin-6, and tumor necrosis factor α, are increased in AD, along with gene expression of major histocompatibility complex (MHC) class II molecules and macrophage migration inhibitory factor (MIF). MHC class II molecules are found in microglia of the brain, while MIF is found in both microglia and neurons of the hypothalamus, hippocampus, and cortex. MIF is not only a lymphocyte mediator but also a pituitary factor with endocrine properties and can mediate phosphorylation of the extracellular signal-regulated kinase-1/2 MAP kinases pathway. In this study, we looked at CD74, an integral membrane protein that acts as both a chaperone for MHC class II molecules as well as a receptor binding site for MIF. CD74 was recently found to be increased in microglia in AD cases compared to age-matched controls, but has not been reported in neurons. In our analysis, immunohistochemistry revealed a significant increase in CD74 primarily in neurofibrillary tangles, amyloid-β plaques, and microglia. This is the first finding to our knowledge that CD74 is increased in neurons of AD cases compared to age-matched control cases.
Expression and regulation of neurotrophins in the nondegenerate and degenerate human intervertebral disc
Authors: Purmessur Devina , Freemont Anthony J , Hoyland Judith A
Published: September 2008

Introduction

The neurotrophins nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) have been identified in the human intervertebral disc (IVD) and have been implicated in the mechanisms associated with nerve ingrowth and nociception in degeneration of the IVD. The aim of the current study was to investigate an association between neurotrophin expression in the IVD and the severity of disc degeneration, including the effect of disc-related proinflammatory cytokines on neurotrophin and neuropeptide expression in cells derived from the human IVD.

Methods

Immunohistochemical analysis was performed to examine the expression of NGF, BDNF and their high-affinity receptors Trk-A and Trk-B in human IVD samples, divided into three categories: non-degenerate, moderate degeneration and severe degeneration. In order to study the effect of disc-related cytokines on neurotrophin/neuropeptide gene expression, nucleus pulposus cells derived from non-degenerate and degenerate IVD samples were seeded in alginate and were stimulated with either IL-1β or TNFα for 48 hours. RNA was extracted, cDNA was synthesised and quantitative real-time PCR was performed to examine the expression of NGF, BDNF and substance P.

Results

Immunohistochemistry showed expression of NGF and BDNF in the native chondrocyte-like cells in all regions of the IVD and in all grades of degeneration. Interestingly only BDNF significantly increased with the severity of degeneration (P < 0.05). Similar expression was observed for Trk-A and Trk-B, although no association with disease severity was demonstrated. In cultured human nucleus pulposus cells, stimulation with IL-1β led to significant increases in NGF and BDNF gene expression (P < 0.05). Treatment with TNFα was associated with an upregulation of substance P expression only.

Conclusion

Our findings show that both the annulus fibrosus and nucleus pulposus cells of the IVD express the neurotrophins NGF and BDNF, factors that may influence and enhance innervation and pain in the degenerate IVD. Expression of Trk-A and Trk-B by cells of the nondegenerate and degenerate IVD suggests an autocrine role for neurotrophins in regulation of disc cell biology. Furthermore, modulation of neurotrophin expression by IL-1β and modulation of substance P expression by TNFα, coupled with their increased expression in the degenerate IVD, highlights novel roles for these cytokines in regulating nerve ingrowth in the degenerate IVD and associated back pain.
Biologic activity and safety of belimumab, a neutralizing anti-B-lymphocyte stimulator (BLyS) monoclonal antibody: a phase I trial in patients with systemic lupus erythematosus
Authors: Furie Richard , Stohl William , Ginzler Ellen M , Becker Michael , Mishra Nilamadhab , Chatham Winn , Merrill Joan T , Weinstein Arthur , McCune W Joseph , Zhong John , Cai Wendy , Freimuth William ,   the Belimumab Study Group
Published: September 2008

Introduction

This trial evaluated the safety, biologic activity, and pharmacokinetics of belimumab, a fully human monoclonal antibody that inhibits the biologic activity of the soluble form of the essential B-cell survival factor B-lymphocyte stimulator (BLyS) in patients with systemic lupus erythematosus (SLE).

Methods

Seventy patients with mild-to-moderate SLE were enrolled in a phase I, double-blind, randomized study and treated with placebo (n = 13) or belimumab (n = 57) at four different doses (1.0, 4.0, 10, and 20 mg/kg) as a single infusion or two infusions 21 days apart. Patients were followed for 84 to 105 days to assess adverse events, pharmacokinetics, peripheral blood B-cell counts, serology, and SLE disease activity. Data from the study were summarized using descriptive statistics. χ2 type tests were used to analyze discrete variables. The Kruskal-Wallis test, the Wilcoxon test, and the analysis of covariance were used to analyze the continuous variables, as appropriate. The analysis was performed on all randomized patients who received study agent.

Results

The incidences of adverse events and laboratory abnormalities were similar among the belimumab and placebo groups. Belimumab pharmacokinetics were linear across the 1.0 to 20 mg/kg dose range. Long terminal elimination half-life (8.5 to 14.1 days), slow clearance (7 ml/day per kg), and small volume of distribution (69 to 112 ml/kg) were consistent with a fully human antibody. Significant reductions in median percentages of CD20+ B cells were observed in patients treated with a single dose of belimumab versus placebo (day 42: P = 0.0042; and day 84: P = 0.0036) and in patients treated with two doses of belimumab versus placebo (day 105: P = 0.0305). SLE disease activity did not change after one or two doses of belimumab.

Conclusions

Belimumab was well tolerated and reduced peripheral B-cell levels in SLE patients. These data support further studies of belimumab in autoimmune disorders.

Trial Registration

NCT00657007 [clinicaltrials.gov].
Pressure support ventilation attenuates ventilator-induced protein modifications in the diaphragm
Authors: Futier Emmanuel , Constantin Jean-Michel , Combaret Lydie , Mosoni Laurent , Roszyk Laurence , Sapin Vincent , Attaix Didier , Jung Boris , Jaber Samir , Bazin Jean-Etienne
Published: September 2008

Introduction

Controlled mechanical ventilation (CMV) induces profound modifications of diaphragm protein metabolism, including muscle atrophy and severe ventilator-induced diaphragmatic dysfunction. Diaphragmatic modifications could be decreased by spontaneous breathing. We hypothesized that mechanical ventilation in pressure support ventilation (PSV), which preserves diaphragm muscle activity, would limit diaphragmatic protein catabolism.

Methods

Forty-two adult Sprague-Dawley rats were included in this prospective randomized animal study. After intraperitoneal anesthesia, animals were randomly assigned to the control group or to receive 6 or 18 hours of CMV or PSV. After sacrifice and incubation with 14C-phenylalanine, in vitro proteolysis and protein synthesis were measured on the costal region of the diaphragm. We also measured myofibrillar protein carbonyl levels and the activity of 20S proteasome and tripeptidylpeptidase II.

Results

Compared with control animals, diaphragmatic protein catabolism was significantly increased after 18 hours of CMV (33%, P = 0.0001) but not after 6 hours. CMV also decreased protein synthesis by 50% (P = 0.0012) after 6 hours and by 65% (P < 0.0001) after 18 hours of mechanical ventilation. Both 20S proteasome activity levels were increased by CMV. Compared with CMV, 6 and 18 hours of PSV showed no significant increase in proteolysis. PSV did not significantly increase protein synthesis versus controls. Both CMV and PSV increased protein carbonyl levels after 18 hours of mechanical ventilation from +63% (P < 0.001) and +82% (P < 0.0005), respectively.

Conclusions

PSV is efficient at reducing mechanical ventilation-induced proteolysis and inhibition of protein synthesis without modifications in the level of oxidative injury compared with continuous mechanical ventilation. PSV could be an interesting alternative to limit ventilator-induced diaphragmatic dysfunction.
Influence of enrollment sequence effect on observed outcomes in the ADDRESS and PROWESS studies of drotrecogin alfa (activated) in patients with severe sepsis
Authors: Laterre Pierre-François , Macias William L , Janes Jonathan , Williams Mark D , Nelson David R , Girbes Amand RJ , Dhainaut Jean-François , Abraham Edward
Published: September 2008

Introduction

We performed a study to determine whether an enrollment sequence effect noted in the PROWESS (recombinant human activated Protein C Worldwide Evaluation in Severe Sepsis) trial exists in the ADDRESS (Administration of Drotrecogin Alfa [Activated] [DrotAA] in Early Stage Severe Sepsis) trial.

Methods

We evaluated prospectively defined subgroups from two large phase 3 clinical trials: ADDRESS, which included 516 sites in 34 countries, and PROWESS, which included 164 sites in 11 countries. ADDRESS consisted of patients with severe sepsis at low risk of death not indicated for treatment with DrotAA. PROWESS consisted of patients with severe sepsis with one or more organ dysfunctions. DrotAA (24 μg/kg per hour) or placebo was infused for 96 hours.

Results

In ADDRESS and PROWESS, there was a statistically significant interaction between the DrotAA treatment effect and the sequence in which patients were enrolled. In both trials, higher mortality was associated with DrotAA use in the subgroup of patients enrolled first at study sites. Compared with placebo, PROWESS mortality was lower with DrotAA treatment for the second and subsequent patients enrolled, whereas in ADDRESS, mortality remained higher for the second patient enrolled but thereafter was lower for DrotAA-treated patients. Comparison of patients enrolled first with subsequent patients enrolled indicated that the characteristics of patients changed. Subsequently enrolled patients were treated earlier, were less likely to suffer nonserious bleeds (ADDRESS), and experienced fewer protocol violations (PROWESS).

Conclusions

Analyses suggest that an enrollment sequence effect was present in the ADDRESS and PROWESS trials. Analysis of this effect on outcomes suggests that it is most apparent in patients at lower risk of death. In PROWESS, this effect appeared to be associated with a reduction of the DrotAA treatment effect for the first patients enrolled at each site. In ADDRESS, this effect may have contributed to early termination of the study. The finding of an enrollment sequence effect in two separate trials suggests that trial designs, site selection and training, data collection and monitoring, and statistical analysis plans may need to be adjusted for these potentially confounding events.

Trial Registration

ADDRESS trial registration number: NCT00568737. PROWESS was completed before trial registration was required.
Functional expression of IgA receptor FcαRI on human platelets
Authors: Qian Kun , Xie Fenglong , Gibson Andrew W , Edberg Jeffrey C , Kimberly Robert P , Wu Jianming
Published: September 2008

FcαRI (CD89) is a human IgA FcR expressed on cells of myeloid lineage such as neutrophils, monocytes, tissue macrophages, eosinophils, and subpopulations of dendritic cells. FcαRI mediates cell activation through Src family kinases and downstream tyrosine-based phosphorylation pathways. However, the role of IgA and the expression and role of its cognate receptor FcαRI (CD89) in platelet activation are undefined. In the current study, we demonstrate that human platelets express FcαRI mRNAs and proteins. Furthermore, we show that the platelet FcαRI is associated with the FcR γ-chain, and cross-linking of FcαRI leads to Syk phosphorylation. Clustering of FcαRI induces pre-mRNA splicing and protein production of tissue factor and IL-1β, suggesting novel roles for human platelet FcαRI and serum IgA in thrombosis and inflammation.
Journal of Music Theoryunder Allen Forte's Editorship
Authors: Berry David Carson
Published: September 2008

This article addresses the role played by Allen Forte in establishing the Journal of Music Theory as a journal of record for the American discipline of music theory, as it emerged and evolved in the 1960s. The journal was founded at Yale University in 1957 by editor David Kraehenbuehl. When he left his position at both the university and the journal in 1960, the editorship passed to Allen Forte, who functioned in that capacity for the next seven years, making him not only the longest-serving editor in the journal's history, but also one at an especially crucial period, when conceptions of the field were beginning to crystallize and circulate in the forms recognizable today. This article explores, in turn, the path Forte took to the journal (and Yale); aspects of editorship, design, and production during his time; the personal imprint he made on the journal, in terms of his editorial agenda; and his departure from the editorship and the legacy he left behind. Quotations from the author's interviews with Forte are included.
Journal of Music Theoryover the Years
Authors: Goldenberg Yosef
Published: September 2008

Bibliometric tools and especially content analysis of all 393 articles published in Journal of Music Theory (up to issue 48/1) help to investigate the development of the content of this journal. The articles were classified according to their type, the theoretical aspect, the period of repertoire discussed, and major composers or theorists they were devoted to. Among the major findings, one can trace in a precise manner the centripetal process toward focus on Schenkerian and set theories (and the more recent opposite process), the almost total separation of discussions of tonal and posttonal music, the more recent inclusion of neo-Riemannian theory, the para-academic nature of some earlier areas of interest, the correlation between an established method and the repertoire discussed, the general solid focus on hard-core theory with very few glimpses to interdisciplinary studies, and the slow and partial change that involves metatheoretical approaches. Other aspects include the growth of the journal, its importance, and its editors and contributors.
Inventing a Melody with Harmony
Authors: Kielian-Gilbert Marianne
Published: September 2008

Intensely chromatic and tonally open, Bach's chorale prelude “Das alte Jahr vergangen ist,” BWV 614, suggests different contexts of reception “as-music-analysis.” I imagine a reception of the prelude as liturgical-musical contemplation and religious experience. I construe Fanny Mendelssohn Hensel's setting of Bach's “Das alte Jahr” in the concluding “Nachspiel” of her piano song cycle, Das Jahr, as suggesting interactions of public and private sonic worlds. I follow potential tonal-harmonic alternatives (after Schoenberg and Berg on the chorale) and implications of staging a motivic parsing through timbre and articulation (after Webern). These differently related interpretive and perceptual contexts shape experience and invoke orientations by which the music-structural aspects of a work can be construed and experienced. Bringing two or more contexts together stimulates new levels and types of connection, just as a melodic pattern continually recalibrates and interacts with potential harmonic and contrapuntal orientations. Changing or shifting emphases in one orientation respond to the demands or constraints of another; in particular, I track the tonal potential of interactions of prolongational, associative, or stretto-like musical figurations in the prelude. These “differences” in orientation become creative and expressive of newly available content, multiplying interactions of composition and text, reception and analysis.
Key Structure in “Das alte Jahr vergangen ist”
Authors: Temperley David
Published: September 2008

My discussion of Bach's chorale prelude “Das alte Jahr vergangen ist” centers on its key structure: the hierarchical arrangement of keys in the piece and the relationships between them. In the course of this discussion, I make a number of observations about the nature of key structure and the factors that govern our perception of it. I begin by considering one of Bach's four-part harmonizations of the chorale and then turn to the chorale prelude itself.
Size and shape of the resection surface geometry of the osteoarthritic knee in relation to total knee replacement design
Authors: Fitzpatrick C K , FitzPatrick D P , Auger D D
Published: September 2008

This study examines the resection surface geometry of the femur, tibia, and patella in relation to the design of total knee implants. Using a technique known as principal component analysis (PCA), the variation in the resection geometry of the knee was summarized. Of the total variation of the knee, 58 per cent was due to variation in size and 14 per cent was due to varying femoral intercondylar notch width. A PCA was performed on each bone separately and it was found that 60 per cent, 76 per cent and 71 per cent of variation was due to size for the femur, tibia, and patella respectively. Femoral and tibial size were highly correlated ( r = 0.95) while patellar size had poorer correlation with both femoral and tibial size ( r < 0.7). Simple linear dimensions (femoral epicondylar width or tibial mediolateral width) were reliable indicators of knee size. The effect of shape variation, which is generally not accounted for in implant design, was measured. The resected surfaces of each subject were compared with a model of the resection surfaces of the knee which varied in size but not shape. The maximum overhang and underhang of the model on the resection surfaces were measured. There was average maximum model overhang of 3.6 mm and underhang of 3.9 mm in the femur, 2.3 mm overhang and 1.9 mm underhang in the tibia, and 2.6 mm overhang and 2.5 mm underhang in the patella. The maximum coverage that an implant can be expected to provide for a population is quantified. Implant designs which include some shape as well as size variation improve on the implant fit.
Compliant layer bearings in artificial joints. Part 1: The effects of different manufacturing techniques on the interface strength between an elastomeric layer and a rigid substrate
Authors: Burgess I C , Jones E , Scholes S C , Unsworth A
Published: September 2008

The premise that elastomeric materials could be used as one or more of the articulating components in both hip and knee prostheses was postulated first by Unsworth and co-workers. It was thought that such materials might have the capacity to mimic natural joint behaviour more closely than the more rigid bearing surfaces commonly in use. A more natural joint function in artificial joints should promote better tribology, with full fluid-film lubrication being the goal. Early tests showed that this objective could potentially be achieved with a judicious choice of materials and carefully controlled manufacturing techniques. This paper (Part 1 of a two-part series) describes and explains the techniques used to verify the material selection as well as to determine the most appropriate manufacturing procedure to obtain a strong and robust interface between the support and bearing material of the prosthesis. Two polycarbonate urethane (PU) materials with different hardness values (Corethane 80A and Corethane 75D) gave sufficient interfacial strength when moulded under optimum conditions. Corethane 80A was used as the soft bearing material while Corethane 75D provided the rigid backing component. Peel tests revealed strong interface bonds, varying with processing conditions between 350 and 862 N. Fourier transform infrared spectroscopy and micro-thermal analysis showed that a fusion bond over 30 μm thick formed at the interface. The results of the range of tests and analyses, which have been used in this study, have provided sufficient evidence to validate the process used to manufacture these components.
Implantable hearing aids
Authors: Counter P
Published: September 2008

The aim of this article is to give readers a general overview of the concepts involved in the latest generation of implantable hearing aids. A section on ear biomechanics has also been included to familiarize readers with the basic concepts involved. These devices have been developed over the last 20 years, driven by problems with conventional hearing aids and by advances in the understanding of middle-ear mechanics. The use of technology borrowed from cochlear implants has enabled the first generation of fully implantable aids to be trialled. The author examines the theoretical advantages and disadvantages of implantable hearing aids over conventional aids and then reviews the technology and clinical results of a range of devices that have been trialled.
A modular rehabilitation system with enhanced functionality and safety to support improved recovery from injury and quality of life
Authors: Smith J D , West A A
Published: September 2008

The rehabilitation of the range of individuals covering medical patients to elite athletes is a costly and time-consuming process involving the knowledge of experienced physical therapists, medical practitioners, coaches, and dedicated training facilities. In order to improve the effectiveness and efficiency of the rehabilitation process, a modular variable-resistance rehabilitation device has been developed. The mechanical, electromechanical, and software systems identified during this research have been shown to provide a step change in exercise functionality, real-time patient monitoring, performance feedback, and safety. Using distributed network concepts, the physical therapist will be able to design and implement training regimes remotely, which can subsequently be downloaded to the localized resistance devices. The patient and/or athlete is able to complete the required exercises without personal supervision. The data from these sessions can be saved and accessed for assessment at a convenient time, thereby maximizing therapist productivity and optimizing the utilization of medical resources.
Analytical modelling of Kirschner wires in Ilizarov circular external fixators using a tensile model
Authors: Zamani A R , Oyadiji S O
Published: September 2008

Mechanical characteristics of orthopaedic fixators, such as the stiffness and stability, directly influence the mechanobiological environment in which the bone is healed. In circular external fixators, the transfixing Kirschner wires are the major contributors to the biomechanics involved. A comprehensive understanding of the mechanical behaviour of the wires is therefore the key to biomechanical analysis of the Ilizarov fixator. In this study, to model the behaviour of the wires, a purely theoretical approach has been adopted to obtain explicit equations for a solely tension-based model formulation. Mathematical modelling leads to new algebraic polynomials whose solutions are the exact maximum deflection, angle of deflection, and total (final) tension in the wire. The predictions are compared with published experimental and computational findings on the deflection and stiffness of the wires, and analytical explanations are provided for the previously observed behaviours. Parametric (practical) implications of this type of abstraction include the fact that the angle of deflection as well as the tension in the wire are independent of its length. The inverse proportionality of wire stiffness to its length is also deduced. The findings are applicable to tensile elements (ropes, chains, etc.), provided that the tensile deformation (elongation) can be deemed to be the dominant mode of deformation.
Detection of DNA by scraping the formalin-fixed paraffin-embedded tissue
Authors: Bukhari M H , Niazi S , Ghani R , Rathore Z , Basharat R , Chaudhry N A , Naeem S
Published: September 2008

Background. Pakistan is a developing country and most of the research laboratories have limited required infrastructures for the diagnosis of cancer at molecular level. The polymerase chain reaction (PCR) on formalin-fixed paraffin-embedded tissues is becoming a popular procedure in the research centres. The study was conducted to introduce two new methods of DNA extraction for the PCR from formalin-fixed paraffin-embedded sections of surgical pathology specimens. Materials and methods. Two methods of DNA detection were used. In method A the formalin-fixed tissues were grossed, proper sections were taken, processed in an automatic tissue processor, embedded in paraffin blocks, and microtomic sections were made. In method B, the procedure was the same until embedding in the paraffin blocks, after which the selected paraffin blocks were set on a black card paper (4 cm×4 cm) and 1 mg of pure scraped tissue was obtained using a scalpel, manually without using microtone. Results. DNA was successfully extracted but point mutation of p53 gene was not seen in SCP while it was determined in 96 and 93.75 per cent cases of SCC by method A and method B respectively. There was no statistical difference in the results by both methods ( P = 0.359). Conclusion. Scraping of the tissue for DNA detection was a simple method and may be performed in any laboratory. The reliability, reproducibility, and quality assurance of the present results are consistent with the already established techniques of DNA extraction for PCR.
Natural frequency analysis of tooth stability under various simulated types and degrees of alveolar vertical bone loss
Authors: Wang C-H , Liu H-W , Ou K-L , Teng N-C , Yu J-J , Huang H-M
Published: September 2008

The aim of this study was to test natural teeth stability under various simulated types and degrees of alveolar vertical bone loss, as well as to assess the role that the surrounding bone played for maintaining tooth stability. A three-dimensional finite element model of the human maxillary central incisor with surrounding tissue, including periodontal ligament, enamel, dentin, pulp, and alveolar bone, was established. One side and multiple vertical bone loss were simulated by means of decreasing the surrounding bone level apically from the cemento-enamel junction in 1 mm steps incrementally downward for 10 mm. Natural frequency values of the incisor model with various types and degrees of bone loss were then calculated. The results showed that, with one-sided bone resorption, the model with labial bone loss had the lowest natural frequency decreasing rates (8.2 per cent). On the other hand, in cases of multiple bone loss, vertical bone resorption at the mesial and distal sides had more negative effects on tooth stability compared to vertical bone losses on facial and lingual sides. These findings suggest that the natural frequency method may be a useful, auxiliary clinical tool for diagnosis of vertical periodontal diseases.
Use of the pulse transit time trend to relate tidal breathing and central respiratory events
Authors: Foo J Y A , Wilson S J , Lim C S
Published: September 2008

Central sleep apnoea (CSA) is a respiratory event where cessation of breathing effort and airflow occurs. Numerous lumped models have related the physical phenomena in the arterial tree to properties of the arterial wall. However, a limited model is available that describes pulse transit time (PTT) oscillations during CSA and tidal breathing. Data from 28 children (22 males; aged 6.2 ± 3.6 years) were obtained during overnight polysomnography. Using a lumped-element model, PTT fluctuations during both respiratory events were described and compared with actual experimental data. 222 valid CSA and 222 tidal breathing events were acquired and analysed. For the tidal breathing, undamped PTT oscillations of 3.89 s were predicted while actual data showed a mean value of 3.68 ± 0.83 s. Conversely, a damped PTT trend was observed during CSA as predicted by the model. The results attained showed that clustered CSA occurrences led to an increase of 7.23 ± 3.34 per cent in PTT baseline value while the model predicted 7.86 ± 2.63 per cent. The marginal increase in PTT baseline was expected since the blood pressure and heart rate decreased during such occurrences. The findings herein suggest that the described model has the potential to describe respiratory event characteristics of a sleeping child.
Objective functional assessment of total hip arthroplasty following two common surgical approaches: The posterior and direct lateral approaches
Authors: Whatling G M , Dabke H V , Holt C A , Jones L , Madete J , Alderman P M , Roberts P
Published: September 2008

Despite the high number of total hip arthroplasty (THA) procedures performed each year, there is no common consensus on the best surgical approach. Gait is known to improve following THA although it does not return to what is typically quantified as normal, and surgical approach is believed to be a contributing factor. The current study evaluates post-operative hip function and provides an objective assessment following two common surgical approaches: the McFarland—Osborne direct lateral and the southern posterior. Faced with the common problem of providing an objective comparison from the wealth of data collected using motion analysis techniques, the current study investigates the application of an objective classification tool to provide information on the effectiveness of each surgery and to differentiate between the characteristics of hip function following the two approaches. Seven inputs for the classifier were determined through statistical analysis of the biomechanical data. The posterior approach group exhibited greater characteristics of non-pathological gait and displayed a greater range of functional ability as compared with the lateral approach cohort. The classification tool has proved to be successful in characterizing non-pathological and THA function but was insufficient in distinguishing between the two surgical cohorts.
A biomechanical assessment of the coupling of torsion and tension in the human scapholunate ligament
Authors: Zdero R , Olsen M , Elfatori S , Skrinskas T , Schemitsch E , Whyne C , von Schroeder H
Published: September 2008

The mechanical behaviour of human scapholunate ligaments is not well described in the literature with regard to torsion. In this study, intact scapholunate specimens were mechanically tested in torsion to determine whether a simultaneous tensile load was generated. Human intact scapholunate specimens ( n = 19) were harvested. The scaphoid and lunate bones were potted in square chambers using epoxy cement, while the interposing ligament remained exposed. Each specimen was mounted rigidly in a specially designed test jig and remained at a fixed axial length during all tests. Specimens were subjected to a torsional load regime that included cyclic preconditioning, ramp-up, stress relaxation, ramp-down, rest, and torsion to failure. Torque and axial tension were monitored simultaneously. The relationship between torsion and tension was determined. Graphs of torque versus tension were generated, from which outcome measures were extracted. Tests demonstrated a clear relationship between applied torsion and the resulting generation of tension for the ligament during ramp-up (torsion-to-tension ratio, 38.86 ± 29.00 mm; linearity coefficient R2 = 0.89 ± 0.15; n = 19), stress relaxation (torsion-to-tension ratio, 23.43 ± 15.84 mm; R2 = 0.90 ± 0.09; n = 16), and failure tests (torsion-to-tension ratio, 38.81 ± 26.39 mm; R2 = 0.77 ± 0.20; n = 16). No statistically significant differences were detected between the torsion-to-tension ratios ( p = 0.13) or between the linearity ( R2) of the best-fit lines ( p > 0.085). A strongly coupled linear relationship between torsion and tension for the scapholunate ligament was exhibited in all test phases. This may suggest interplay between these two parameters in the stabilization of the ligament during normal motion and for injury cascades.
Effects of diluents on knock rating of gaseous fuels
Authors: Bade Shrestha S O , Rodrigues R
Published: September 2008

Concerns on energy security, emissions, and the recent hike in the price of fossil fuels have prompted the rapidly growing interest in the use of various alternative and renewable fuels, including low heating value fuels such as land-filled gases, biogases, coal bed methane gases, and others. Generally, the low heating value (btu) fuels contain substantial amounts of diluents such as carbon dioxide, nitrogen, water vapour, and other trace gases in the fuel composition. The present contribution describes the results of the investigation of knock in a single-cylinder variable compression ratio (CR) spark-ignition engine fuelled with gaseous fuels, such as natural gas, methane, and hydrogen, in the presence of different amounts of diluents, specifically carbon dioxide and nitrogen, in the fuel mixture in order to represent closely the general composition of land filled and biogases in practice. The knock characteristics of the fuels were quantitatively evaluated in terms of the methane number using various methods. Generally, the addition of either diluent carbon dioxide or nitrogen in the fuel mixtures augmented the knock resistance characteristics extending the engine operational limits. With every 10 per cent increase of carbon dioxide in the fuel mixture, the CR was increased by one point, whereas for a 25 per cent of nitrogen content in the fuel mixture, the CR was augmented by a half point in the operating conditions considered.
Shape optimization of an axial compressor blade by multi-objective genetic algorithm
Authors: Samad A , Kim K-Y
Published: September 2008

In this study, a multi-objective optimization of an axial compressor rotor blade has been performed through genetic algorithm with total pressure and adiabatic efficiency as objective functions. The non-dominated sorting of genetic algorithm-II has been implemented and confidence check has been performed at k-means clustered points among all the Pareto-optimal solutions. Reynolds-averaged Navier—Stokes equations are solved to obtain the objective function and flow field inside the compressor annulus. The objective functions are used to generate Pareto-optimal front. The design variables are selected from blade lean and thickness through the Bezier polynomial formulation. By this optimization, maximum efficiency and total pressure are increased by 1.76 and 0.41 per cent, respectively, when two extreme clustered points are considered as optimal designs.
Three-dimensional computational fluid dynamics model of a tubular-shaped ambient air-breathing proton exchange membrane fuel cell
Authors: Al-Baghdadi M A R S
Published: September 2008

The development of physically representative models that allow reliable simulation of the processes under realistic conditions is essential for the development and optimization of fuel cells, the introduction of cheaper materials and fabrication techniques, and the design and development of novel architectures. A three-dimensional, multi-phase, non-isothermal computational fluid dynamics model of a novel, simple to construct, tubular, proton exchange membrane (PEM) fuel cell which works in still or slowly moving air has been developed. The novel tubular geometry enables optimum air access to the cathode without the need for pumps, fans, or similar devices. This comprehensive model accounts for the major transport phenomena such as convective and diffusive heat and mass transfer, electrode kinetics, transport and phase-change mechanism of water, and potential fields in a tubular-shaped air-breathing PEM fuel cell. The model explains many interacting, complex electrochemical, and transport phenomena that cannot be studied experimentally. Three-dimensional results of the species profiles, temperature distribution, potential distribution, and local current density distribution are presented and analysed, with the focus on the physical insight and fundamental understanding. These results provide a solid basis for optimizing the geometry of the PEM fuel cell stack running in a passive mode.