bluuebunny/crossref_metadata_2025 huggingface dataset:
Ligand‐Stimulated VEGFR2 Signaling is Regulated by Co‐Ordinated Trafficking and Proteolysis
Authors: Bruns Alexander F. , Herbert Shane P. , Odell Adam F. , Jopling Helen M. , Hooper Nigel M. , Zachary Ian C. , Walker John H. , Ponnambalam Sreenivasan
Published: October 2009

Vascular endothelial growth factor A (VEGF‐A)‐induced signaling through VEGF receptor 2 (VEGFR2) regulates both physiological and pathological angiogenesis in mammals. However, the temporal and spatial mechanism underlying VEGFR2‐mediated intracellular signaling is not clear. Here, we define a pathway for VEGFR2 trafficking and proteolysis that regulates VEGF‐A‐stimulated signaling and endothelial cell migration. Ligand‐stimulated VEGFR2 activation and ubiquitination preceded proteolysis and cytoplasmic domain removal associated with endosomes. A soluble VEGFR2 cytoplasmic domain fragment displayed tyrosine phosphorylation and activation of downstream intracellular signaling. Perturbation of endocytosis by the depletion of either clathrin heavy chain or an ESCRT‐0 subunit caused differential effects on ligand‐stimulated VEGFR2 proteolysis and signaling. This novel VEGFR2 proteolysis was blocked by the inhibitors of 26S proteasome activity. Inhibition of proteasome activity prolonged VEGF‐A‐induced intracellular signaling to c‐Akt and endothelial nitric oxide synthase (eNOS). VEGF‐A‐stimulated endothelial cell migration was dependent on VEGFR2 and VEGFR tyrosine kinase activity. Inhibition of proteasome activity in this assay stimulated VEGF‐A‐mediated endothelial cell migration. VEGFR2 endocytosis, ubiquitination and proteolysis could also be stimulated by a protein kinase C‐dependent pathway. Thus, removal of the VEGFR2 carboxyl terminus linked to phosphorylation, ubiquitination and trafficking is necessary for VEGF‐stimulated endothelial signaling and cell migration.
ORIGINAL ARTICLE: The Role of Cytokine Expression in Different Subgroups of Subfertile Men
Authors: Seshadri Srividya , Bates Michelle , Vince Gill , Jones D. I. Lewis
Published: October 2009

Problem  The aim of this study was to evaluate the levels of seminal plasma cytokines interleukin 6 (IL‐6), interleukin 8 (IL‐8), interleukin 10 (IL‐10), interleukin 11 (IL‐11), interleukin 12 (IL‐12), tumour necrosis factor alpha (TNF‐α) and interferon gamma (IFN‐γ) in male subfertility.

Method of study  A total of 73 male partners of an infertile couple attending a regional andrology unit were recruited into this prospective study and subdivided into the various groups based on semen analysis. Concentrations of cytokines such as IL‐6, IL‐8, IL‐10, IL‐11, IL‐12, TNF‐α and IFN‐γ in the seminal plasma were determined using enzyme linked immunosorbent assay (ELISA).

Results  Significant higher concentrations (P < 0.05) of IL‐6 in the mild and severe oligospermic group, IL‐8 and IL‐10 in the asthenospermic group and IL‐6, IL‐10, TNF‐α and IFN‐γ in the obstructed azoospermic group were determined. IL‐10 concentrations correlated significantly with other cytokines in the obstructed azoospermic group and the asthenospermic group.

Conclusion  Our study confirms that cytokines rarely act in isolation, but rather in a network of other cytokines and may affect sperm function directly or indirectly. The presence of increased levels of cytokines in the obstructed azoospermic group suggests that the cytokines may not originate from the testis.
ORIGINAL ARTICLE: Multiple Cytokine Profile in Plasma and Amniotic Fluid in a Mouse Model of Pre‐Term Labor
Authors: Yang Qing , El‐Sayed Yasser , Rosenberg‐Hasson Yael , Hirschberg David L. , Nayak Nihar R. , Schilling James , Madan Ashima
Published: October 2009

Problem  The rate of pre‐term birth in the United States continues to rise despite several interventions. Induction of pro‐inflammatory cytokines and chemokines has been implicated in the activation of the cascade of events resulting in pre‐term labor. To date, no comprehensive panel of the cytokine profile in PTL has been published.

Method of study  To address cytokine profiles in pre‐term labor, levels of 19 plasma and amniotic fluid cytokines were measured using a multiplex immunoassay in an inflammation‐induced murine model of pre‐term labor.

Results  Pro‐inflammatory mediators, RANTES, KC, IL‐6, and IL‐12p40 were increased by 3 hr and remained high at 15 hr. Concentrations of KC, IL‐6, IL‐1β, and MIP‐1α were increased in the amniotic fluid at 15 hr. Plasma levels of anti‐inflammatory mediators IL‐10 and IL‐13 at 15 hr were unchanged and decreased respectively.

Conclusion  These results suggest that stimulation of several pro‐inflammatory cytokines occurs very early in the cascade of events and remains increased, whereas anti‐inflammatory cytokines are either unchanged or decreased until the onset of delivery in an inflammation‐induced mouse model of pre‐term labor.
Social and behavioral risk factors for maxillary incisor trauma in an adolescent Arab population
Authors: Årtun Jon , Al‐Azemi Rashed
Published: October 2009

Abstract –  Background/Aim: The majority of dental traumas are due to falls or blows during regular activity, personal interaction and play inside or outside the home, suggesting that behaviors associated with certain social conditions are risk factors. Our purpose was to explore that hypothesis.

Materials and Methods:  We examined a population‐based sample of 1583 13–14‐year‐old subjects in a classroom setting. Incisor trauma was scored according to the National Institute of Dental Research index, and overjet was measured to the nearest 0.5 mm. Presence of mesial migration and/or loss of first molars and/or open caries in permanent teeth were recorded and categorized as increased caries experience. Body mass index (BMI) was calculated from standardized measurements of height and weight, as weight in kg height−1 in m2. Obesity was scored if BMI exceeded 30. Information on participation in physical activities, family income, and number of siblings was collected through subject and family interview.

Results and Conclusions:  Univariate logistic regression detected reduced trauma risk among subjects of high income families (P = 0.009) and among subjects attending private schools (P = 0.026). Sports and physical activities were more prevalent in boys than in girls (P = 0.000) and associated with trauma in the sample as a whole (P = 0.001), but not separately in boys and girls. No effect was detected of obesity, number of siblings and increased caries experience. Univariate analyzes also detected increased trauma risk in boys (P = 0.000) and in subjects with increasing intervals of overjet (P = 0.000). Following use of multiple regressions with forward selection, only male gender, increasing overjet, and high family income were included in the final prediction model. Our findings suggest that behaviors associated with high family income and private school attendance reduce the risk of incisor trauma among adolescents in Kuwait, and that the gender difference in sports activities is an unlikely explanation for the gender difference in trauma.
MitoPark mice mirror the slow progression of key symptoms and L‐DOPA response in Parkinson's disease
Authors: Galter D. , Pernold K. , Yoshitake T. , Lindqvist E. , Hoffer B. , Kehr J. , Larsson N.‐G. , Olson L.
Published: October 2009

The MitoPark mouse, in which the mitochondrial transcription factor Tfam is selectively removed in midbrain dopamine (DA) neurons, is a genetic model for Parkinson's disease (PD) that replicates the slow and progressive development of key symptoms. To further validate this model, we have extended both behavioral and biochemical analyses in these animals. We found that vertical movements decline earlier and faster than horizontal movements, possibly modeling the early occurrence of axial, postural instability in PD. L‐DOPA induces different locomotor responses depending on the age: in young MitoPark mice the L‐DOPA‐induced motor activation is small; middle‐aged MitoPark mice respond in a dose‐dependent manner to L‐DOPA, whereas aged MitoPark mice display a double‐peaked locomotor response to a high dose of L‐DOPA that includes an intermittent period of very low motor activity, similar to the ‘on–off’ phenomenon in PD. To correlate behavior with biochemical data, we analyzed monoamine levels in three different brain areas that are highly innervated by the DA system: striatum, anterior cortex and olfactory bulb. DA levels declined earlier and faster in striatum than in cortex; only at the latest time‐point analyzed, DA levels were found to be significantly lower than control levels in the olfactory bulb. Interestingly, the ratio between homovanillic acid (HVA) and DA differed between regions over time. In striatum and olfactory bulb, the ratio increased steeply indicating increased DA turnover. In contrast, the ratio decreased over time in cortex, revealing important differences between DA cells in substantia nigra and the ventral tegmental area.
The D2 dopamine receptor gene variant C957T affects human fear conditioning and aversive priming
Authors: Huertas E. , Ponce G. , Koeneke M. A. , Poch C. , España‐Serrano L. , Palomo T. , Jiménez‐Arriero M. Á. , Hoenicka J.
Published: October 2009

Polymorphisms of DRD2 and ANKK1 have been associated with psychiatric syndromes where there is believed to be an underlying learning process deficit such as addiction, post‐traumatic stress disorder and psychopathy. We investigated the effects of the DRD2 C957T and ANKK1 TaqIA single nucleotide polymorphism (SNP), which have been associated with psychopathic traits in alcoholic patients, on fear conditioning and aversive priming in healthy volunteers. We found that the DRD2 C957T SNP, but not the ANKK1 TaqIA SNP, was associated with both differential conditioning of the skin conductance response and the aversive priming effect. There were no differences between the genotype groups with respect to the extinction of the skin‐conductance conditioned response. These results suggest that the C957T SNP could be related to learning differences associated with the risk of developing psychiatric disorders in individuals that are carriers of the C homozygous genotype. Our genetic data raise the possibility that the dopaminergic system functional variations determined by this SNP could affect fear learning.
Longitudinal correlates of the persistence of irregular eating from age 5 to 14 years
Authors: McDermott BM , Mamun AA , Najman JM , Williams GM , O’Callaghan MJ , Bor W
Published: October 2009

Aim:  To report the stability of parent‐perceived child irregular eating from 6 months to 14 years of age and to investigate a predictive model inclusive of child and parent factors.

Methods:  Of the 7223 singleton children in a birth cohort, 5122 children were re‐interviewed at 5 years and 4554 for the 14‐year analysis. Information was obtained from structured interviews including questions answered by parents of the child at birth, 6 months, 5 years and 14 years; and by teenagers at age 14 years and from physical measures of the child. The mother’s perception that the child was an irregular eater at age 14 years was the major outcome variable of interest.

Results:  Approximately 40% of irregular eaters at age 5 will still be irregular eaters at age 14 years. This was not related to maternal education or socio‐economic class. Significant at multivariate analysis were infant feeding problems and the children’s ability to regulate their sleep and mood. Significant maternal factors were greater age, not feeling positive about the baby and persistent maternal anxiety during the child’s early years.

Conclusion:  Irregular eating behaviour displays considerable continuity from childhood to mid‐adolescence. Independent contributions to this behavioural phenotype include child biological and psychological factors and maternal anxiety during the child’s early years.
OPENING PHILOSOPHY TO THE WORLD: DERRIDA AND EDUCATION IN PHILOSOPHY
Authors: Burik Steven
Published: October 2009

Abstract

In this essay, Steven Burik discusses Jacques Derrida's position with regard to the place of education in philosophy within the university system, and then relates these thoughts to comparative philosophy. Philosophers find themselves constantly having to defend philosophy and the importance of teaching philosophy against pressure from the powers that be. Burik contends that the argument Derrida set forth to “protect” philosophy entails a double bind: Derrida emphasized the value and importance of philosophical thinking while at the same time criticizing the limits of philosophy, both self‐mandated and externally imposed. Derrida's defense of philosophy was anything but a protection of the status quo, according to Burik. Derrida ultimately argued that the teaching of philosophy and philosophy itself should be inherently open to new developments. Burik relates Derrida's defense of philosophy and attack on mainstream philosophy to comparative philosophy, demonstrating that both argue for an expansion of thinking beyond the narrow Western confines of philosophy as “pure” reason or rationality by showing how alterity always inserts itself, and that both seek to give this alterity a valid place in educational systems.
PROLEGOMENA TO A NEW ACADEMIC RESPONSIBILITY: WHAT IT MEANS TO KNOW AND THE UNIVERSITY
Authors: Trifonas Peter
Published: October 2009

Abstract

In this essay, Peter Trifonas tries to show that there is no overcoming of the techno‐philosophical grounding of intellectual freedom and academic responsibility or research action within the speculum of an all‐seeing, all‐knowing university. Instead, he argues that through Derrida's notion of an open “community of the question,” deconstruction has the promise to infuse the university and its teaching body with the play of difference in interpretation and invention that will produce new forms of knowledge and an altered academic responsibility. This new academic responsibility born of a deconstruction of the university and its closed system of disciplinary logic is worked out as a performative intelligibility or an inkling of purpose “yet‐to‐come” (avenir). The call for an open community of research around questions and not disciplines displays the ethical undercurrent of a new kind of academic responsibility—a responsibility negotiated both within the extant community and between that community and those to whom the highly problematic “we” of “higher” education are more or less ultimately accountable: the State and the political constituency of public society.
Effect of siRNA terminal mismatches on TRBP and Dicer binding and silencing efficacy
Authors: Kini Hemant K. , Walton S. P.
Published: October 2009

To enhance silencing and avoid off‐target effects, siRNAs are often designed with an intentional bias to ensure that the end of the siRNA that contains the guide strand 5′ end is less stably hybridized relative to the end containing the passenger strand 5′ end. One means by which this is accomplished is to introduce a terminal mismatch, typically by changing the passenger strand sequence to impair its hybridization with the guide strand 5′ end. However, there are conflicting reports about the influence of terminal mismatches on the silencing efficacy of siRNAs. Here, the silencing efficiency of siRNAs with a terminal mismatch generated either by altering the guide strand (at the 5′ end, nucleotide 1) or the passenger strand (nucleotide 19 from the 5′ end) was examined. Subsequently, we studied the relationship between the silencing efficiency of the siRNAs and their binding to the RNA‐induced silencing complex loading complex proteins HIV transactivating response RNA‐binding protein and Dicer in H1299 cytoplasmic extracts. Binding of siRNA and the transactivating response RNA‐binding protein was significantly reduced by terminal mismatches, which largely agrees with the reduction in eventual silencing efficacy of the siRNAs. Single terminal mismatches led to a small increase in Dicer binding, as expected, but this did not lead to an improvement in silencing activity. These results demonstrate that introduction of mismatches to control siRNA asymmetry may not always improve target silencing, and that care should be taken when designing siRNAs using this technique.
Deciphering solar turbulence from sunspots records
Authors: Plunian F. , Sarson G. R. , Stepanov R.
Published: October 2009

It is generally believed that sunspots are the emergent part of magnetic flux tubes in the solar interior. These tubes are created at the base of the convection zone and rise to the surface due to their magnetic buoyancy. The motion of plasma in the convection zone being highly turbulent, the surface manifestation of sunspots may retain the signature of this turbulence, including its intermittency. From direct observations of sunspots, and indirect observations of the concentration of cosmogenic isotopes 14C in tree rings or 10Be in polar ice, power spectral densities in frequency are plotted. Two different frequency scalings emerge, depending on whether the Sun is quiescent or active. From direct observations we can also calculate scaling exponents. These testify to a strong intermittency, comparable with that observed in the solar wind.
Apical resorption in teeth with periapical lesions: Correlation between radiographic diagnosis and SEM examination
Authors: Vier‐Pelisser Fabiana Vieira , de Figueiredo José Antonio Poli , Reis Só Marcus Vinícius , Estivallet Lisiane , Eickhoff Sílvia Juliana
Published: October 2009

This study correlated the radiographic findings and scanning electron microscopy (SEM) images of external apical resorption (EAR) in teeth with periapical lesions. Standard radiographs were taken from 45 teeth with periapical lesions before their extraction. Using a radiographic examination, the root apex of each tooth was classified according to the EAR into the following categories: radiographic external apical resorption (REAR) absent, superficial and deep. The apical root surface was also examined with SEM. Photomicrographs of EARs were classified as periforaminal (PEAR) and foraminal (FEAR) in three degrees: 0, 1 and 2. REAR was present in 72.5% of cases, of which 20% were deep. Based upon SEM analysis, PEAR and FEAR occurred in 75.6% and 66.7% of cases respectively; 51.2% and 59% respectively, of these teeth received a score of 2. Only 15.4% of the specimens were unaffected by EAR.

When teeth with periapical lesions were examined for EAR with both radiography and by SEM, there was no correlation between the findings.
Phumdi proliferation: a case study of Loktak lake, Manipur
Authors: Singh Abha Lakshmi , Khundrakpam Moirang Leima
Published: October 2009

Floating mats are locally known as phumdis. They are a heterogeneous mass of soil, vegetation and organic matter at various stages of decomposition. Phumdis play an important role in the ecological processes and functions of the lake ecosystem. The presence of phumdis is the characteristic feature of the Loktak lake, the largest freshwater wetland located in the north‐eastern part of India about 38 km from Imphal city of Manipur. Phumdis cover nearly 50% of the lake. In this paper, an attempt has been made to examine the changes in phumdi area, analyse the factors causing its proliferation and the resultant impacts on the environment. The study is based on remotely sensed data of 1989 and 2002. To examine the factors causing its proliferation, field surveys were conducted and data covered eight villages and 377 households. The results showed that the phumdi area has increased from 1989 to 2002. The main causes for phumdi proliferation were the construction of the Ithai Barrage Dam, increase in athaphum fishing, pollution, growth of settlements on phumdis, etc. It was the human pressure that has aided in the growth of phumdis.
Sensory acceptability of a reformulated reduced salt frozen ready meal
Authors: Mitchell Michelle , Brunton Nigel P. , Wilkinson Martin G.
Published: October 2009

This study investigated the effect of reducing salt levels and the addition of salt substitutes on the sensory acceptability of a frozen lasagne ready meal. Commercially produced lasagne with standard salt levels (1.05% NaCl) and lasagne with reduced salt levels (0.55% NaCl) was supplied by an industrial partner. Salt was added to the reduced salt meal via the meat sauce layers at levels to produce meals with salt concentrations of 0.55%, 0.65%, 0.75% and 0.85%. Paired comparison and triangle tests indicated that 0.3% of salt could be removed without a sensory difference being observed (P > 0.05). Salt substitutes were incorporated into the lowest salt lasagne ready meal at a concentration of 0.5%. Triangle, paired comparison and preference tests were carried out on these meals to determine acceptability. A consumer acceptability trail conducted with 175 consumers found that the low‐salt KCl meal was preferred over the control (P > 0.1).
Thrombotic Microangiopathies: Multimers, Metalloprotease, and Beyond
Authors: Moake Joel
Published: October 2009

The pathophysiology of various types of thrombotic microangiopathies is coming progressively into focus. Therapeutic advances are likely to follow at a quickening pace. This discussion focuses on thrombotic thrombocytopenic purpura (TTP), the hemolytic‐uremic syndrome (HUS), thrombotic microangiopathies associated with transplantation‐immunosuppression or anti‐angiogenesis therapy, and the preeclampsia/hemolysis‐elevated liver enzymes and low platelets syndrome (HELLP).
Sequence analysis of Vibrio cholerae orfU and zot from pre‐CTXΦ and CTXΦ reveals multiple origin of pre‐CTXΦ and CTXΦ
Authors: Mantri Chinmay K. , Mohapatra Saswat S. , Colwell Rita R. , Singh Durg V.
Published: October 2009

A multiplex PCR was developed to detect pre‐CTXΦ and CTXΦ in Vibrio cholerae. A total of 115 V. cholerae were tested, of which 42 V. cholerae O1 and 18 V. cholerae O139 contained CTXΦ. Six V. cholerae O139 contained only pre‐CTXΦ and three V. cholerae O1 and 23 V. cholerae O139 contained both pre‐CTXΦ and CTXΦ. None of the V. cholerae non‐O1 and non‐O139 that were tested had pre‐CTXΦ or CTXΦ. Results of Restriction Fragment Length Polymorphism (RFLP) analysis revealed the V. cholerae isolates possessed single or multiple copies of pre‐CTXΦ and CTXΦ, always proceeded by a tandemly arranged RS1 element. Comparative nucleotide sequence analyses of the core region genes, orfU and zot, of 15 V. cholerae showed pre‐CTXETΦ and CTXETΦ lineage with V. cholerae El Tor and pre‐CTXClassΦ, pre‐CTXCalcΦ, and CTXCalcΦ with classical V. cholerae O1 and O139. Two distinct types of ctxB were detected in V. cholerae O139. Multi‐locus Sequence Typing (MLST) of seven V. cholerae housekeeping genes indicated clonal origin, irrespective of the presence of pre‐CTXΦ and/or CTXΦ.
Impaction Bone Grafting of the Glenoid in Revision Shoulder Arthroplasty: Classification, Technical Description and Early Results
Authors: Page Richard S. , Haines John F. , Trail Ian
Published: October 2009

Background

Glenoid component fixation remains an issue in the long-term survival of total shoulder arthroplasty. As a consequence revision of the glenoid component is becoming increasingly more common and reconstructive techniques to preserve and restore bone stock are becoming more important.

Methods

In this article we describe the combined technique of impaction grafting and glenoid component exchange together with a classification of the glenoid defect with a report on four sequential cases in patients with rheumatoid arthritis with an average age of 56 years. The minimum follow-up was 34 months (range 34 months to 62 months).

Results

Patients reported excellent pain relief and some improvement in motion and function. The complication rate remains low. Radiological assessment using tomograms showed good incorporation of the bone graft and minimal signs of glenoid loosening.

Conclusion

The results of this study confirm that at least in the short term impaction grafting techniques used to reconstitute the glenoid in revision surgery can be successful.
Physiotherapy in the Management of Tennis Elbow: A Review
Authors: Jones Val
Published: October 2009

What is already known on this topic

Tennis elbow is a chronic condition that can be challenging to treat. Physiotherapy is often a treatment of choice, but previous reviews have failed to draw any conclusions as to which is the most effective therapeutic modality in the management of this condition.

Key messages of this review

The best available evidence is for active exercise approaches, possibly supplemented by manual therapy and taping treatments. There is insufficient evidence to recommend the use of passive modalities such as electrotherapy or acupuncture at present. Physiotherapy is a cost effective form of treatment.
Arthroscopic Capsular Release: A Prospective Double-Blind Randomized Study Comparing Two Types of Rehabilitation Regime. A Pilot Study
Authors: Tan Chin Khoon , Guisasola Inigo , Singh Sameer , Penna Sreeram , Kemp Graham , Brownson Peter
Published: October 2009

Background

The aim of this study was to evaluate, prospectively, outcomes following arthroscopic capsular release on patients with a clinical diagnosis of frozen shoulder, comparing immediate mobilization (IM) vs immediate mobilization plus external rotation splintage at night for 10 nights (IM+EXT).

Methods

Patients with a clinical diagnosis of non-traumatic frozen shoulder seen in a single unit from May 2005 to December 2006 were considered for inclusion. Patients were assessed using the Constant score, Oxford shoulder questionnaire, and a visual analogue scale for pain (VAS pain). Patients were randomized to have immediate mobilization (IM) or immediate mobilization plus external rotation splintage at night for 10 nights (IM+EXT).

Results

Thirty patients were included and both groups showed significant improvement in all scores. Mean length of follow-up was 17 months. There was early (4 weeks post-operatively) significant improvement in shoulder function in both groups. The rehabilitation regime used did not affect the overall outcome.

Conclusions

Arthroscopic capsular release produces early symptom improvement in primary frozen shoulder. The use of an external rotation splint at night does not appear to improve outcome over simple early mobilization.
The UKUFF Trial and the NIHR Comprehensive Local Research Networks
Authors: Carr Andrew , Cooper Cushla
Published: October 2009

Research opportunities in the NHS have changed greatly over the last year or so. The UKUFF study demonstrates the advantages of these changes to orthopaedic research. Analysing the recruitment rates of each surgeon involved in the study found inconsistencies in recruitment patterns. As a result projected recruitment targets were suffering. The UKUFF team took advantage of the new research initiative and at the end of 2008 obtained the support offered by the new infrastructure at many participating sites. The recruitment total at the end of June 2009 showed that supported sites recruited almost double the number of patients compared to the unsupported sites. Surgeons involved in research need to access available resources to help them improve their participation in research. Being actively involved in specialist research like UKUFF can lead to further support for new studies instigated by shoulder surgeons.
A Generalized Method for Estimating Multiaxial Elastic-Plastic Notch Stresses and Strains, Part 2: Application and General Discussion
Authors: Hoffmann M. , Seeger T.
Published: October 2009

The approximation method presented in a previous paper is applied to a round bar with a circumferential notch under tensile load and to a thick-walled cylinder under internal pressure. By comparison with FE-results aspects of accuracy are discussed. Remarks to combined loading cases and to validity of an introduced lateral constraint assumption and Hencky’s equations close the paper.
Analysis of Upsetting With Profiling Dies
Authors: Vilotic Dragisa , Shabaik Aly H.
Published: October 2009

The stress analysis in the deformation zone in upsetting of a workhardening material by half-cylindrical die is presented. The load and average pressure as a function of die stroke were determined and compared to those obtained from experiments. The effect of friction and die radius were examined. Stress distributions for ideal-plastic material were also obtained and the results were compared to those for workhardening material.
Deformations and Stresses in Butt-Welding of Large Plates With Special Reference to the Mechanical Material Properties
Authors: Jonsson Mikael , Karlsson Lennart , Lindgren Lars-Erik
Published: October 2009

Simulation of automatic butt-welding of large plates was investigated. Two different steels were considered. The plates were tack-welded before the butt-welding. The simulation includes the tack-welding, the butt-welding and the cooling to room temperature. The simulations should lead to an understanding of the mechanics behind the change in gap width in front of the moving arc, which is of importance in automatic welding production. The residual stresses due to the butt-welding were also studied. The magnitude and the distribution of the residual stresses are important in design of welded structures. The change in gap width in front of the moving arc and the residual stresses depend on the material in the plates, the restraints of the plates, the size of the plates and the welding parameters. The most important welding parameters are the arc energy per unit length of the weld and the welding speed. The change in gap width depends also on the tack-welding procedure.
Stress Concentrations for Filled and Unfilled Closely Spaced Cylindrical Defects
Authors: Ihara T. , Shaw M. C.
Published: October 2009

All real materials contain defects which significantly reduce the fracture stress of brittle materials. It has been proposed by Griffith [3] that brittle fracture occurs when the maximum intensified tensile stress on the surface of a defect reaches a critical value. It has recently been found [1] that for many brittle materials of high quality, the nature and density of the defects are such that they may be modelled by isolated cylindrical voids. This study considers the stress intensification consequences of the close spacing of cylindrical defects that are filled with a material having a Young’s modulus different than that of the matrix.
Dynamic Emission of Dislocations From a Moving Crack
Authors: Zhao Rui-Huan , Li J. C. M.
Published: October 2009

The emission of dislocations from a propagating crack in the mode II or III situations is studied by computer simulation. While the crack is moving the steady state number of dislocations is smaller than the saturation number which could be emitted from a stationary crack and such a steady state number decreases with increasing crack velocity. The effect on the emission process of the applied stress, the lattice friction for dislocation motion and the critical stress intensity factor for dislocation emission is studied. The results include also the plastic zone size, the dislocation distribution, the dislocation-free zone, and the instantaneous crack velocity. The average crack velocity does not depend on the applied stress but depends only on the critical stress intensity factor for dislocation emission. When such a factor is zero as assumed in some theories, the crack does not move at all.
Plastic Deformation Behavior of Type 316 Stainless Steel Subject to Out-of-Phase Strain Cycles
Authors: Ohashi Y. , Tanaka E. , Ooka M.
Published: October 2009

To elucidate the plastic behavior of metals under out-of-phase strain cycles, a series of experiments was performed on square strain trajectories in a vector space of deviatoric strain by applying combined axial force and torque to thin-walled tubular specimens of type 316 stainless steel. It was confirmed that strain hardening under out-of-phase cycles is much more significant than that under simple cycles. Though the combined isotropic-kinematic hardening model based on the concept of a nonhardening strain region proposed by Ohno gave qualitatively better predictions than the kinematic hardening model by Oak Ridge National Laboratory, there was still a considerable discrepancy between the former theory and the experiment.
Limit Strains for Thin-Walled Tubes With Initial Thickness Inhomogeneity
Authors: Ragab A. R. , Khorshid S. A. , Takla R. M.
Published: October 2009

Limiting strains during tube bulging have been investigated for long tubes subjected to an internal pressure together with an external axial force. A strain instability criterion which takes into consideration the inevitable geometrical defects in the tube wall is developed. The results revealed that small eccentricities produce a substantial decrease in the amount of deformation sustained by the tube at instability conditions. Moreover, the sensitivity to such defects increases for tubes made of low strain-hardening materials. The developed strain instability criterion has been subjected to an experimental verification where commercially pure aluminium tubes have been bulged to fracture. Experimental results are found to be in good agreement with theory, thus justifying the validity of this instability criterion and the resulting limit strains.
In-Service Degradation of Toughness of Steam Turbine Rotors
Authors: Viswanathan R. , Bruemmer S. M.
Published: October 2009

The toughness of steam turbine rotors degrades with time of service exposure in the range of 340°–540°C. There is a need to estimate the toughness degradation that has occurred in order to assess the reliability, remaining life, and further operational parameters for the rotors. Since it is not possible to take large specimens from operating rotors to evaluate the rotor toughness, nondestructive or relatively nondestructive techniques involving removal of small samples are needed. To serve this need, several techniques such as composition based correlations, grain boundary analysis by Auger electron spectroscopy, analytical electron microscopy, and secondary ion mass spectroscopy, chemical and electrochemical etching, eddy current measurements and mechanical testing of miniature samples have been explored by the electric power industry. This paper presents an overview of the principal results emerging from the various on-going projects in this area.
Effect of Coal Liquefaction Solvents on Fatigue Crack Initiation in 2 1/4 Cr-1 Mo Steel and 316L Stainless Steel
Authors: Gross T. S. , Mathews V. K. , Kanga P. N.
Published: October 2009

Blunt notch fatigue crack initiation tests were carried out on 2.25 Cr – 1 Mo steel and 316L stainless steel in room temperature air and in the process solvent from the Wilsonville, Alabama coal liquefaction pilot plant at 100°C. The crack initiation lifetime in the coal liquids at 100°C was an order of magnitude greater than the crack initiation lifetime in air for the 2.25 Cr–1 Mo steel. The crack initiation lifetime in the coal liquids for the 316L stainless steel was increased a factor of five over the crack initiation lifetime in air. The improvement in crack initiation lifetime was attributed to the coal liquids shielding the materials from atmospheric embrittlement. The coal liquids did not show any tendency to form sulfide corrosion products at 100°C.
The Effect of Foam Filling Upon the Energy Absorption of Spot Welded Sheet Metal Tubes
Authors: Thornton P. H. , Amberger C. J.
Published: October 2009

The effect of shell material properties and foam density on the energy absorption of spot welded, square section sheet steel tubes was studied. It was found that as the sheet material tensile strength increased, the effectiveness of the foam in increasing the energy absorption capability diminished. The observed changes in energy absorption could be predicted reasonably accurately by a simple model which correlated shell material property, section geometry, and foam density.
Susceptibility of a Dual Phase Steel to Hydrogen Embrittlement
Authors: Sudarshan T. S. , Pruitt N. C. , Louthan M. R. , Place T. A.
Published: October 2009

Dual phase steels are used in many applications for which electroplating is required. Hydrogen absorption and consequent loss of strength and ductility is therefore possible. Tensile tests and subsequent fractographic analysis of charged and uncharged specimens of a dual phase steel showed that hydrogen absorption resulted in deterioration of tensile properties. The deterioration was attributed to weakening of interfaces between ferrite and other constituents.
Low Cycle Fatigue Crack Growth Behavior at Elevated Temperature Under the Combined Strain-Wave-Shape Cycling in Type 304 Stainless Steel
Authors: Okazaki M. , Hattori I. , Ikeda T. , Koizumi T.
Published: October 2009

The low-cycle fatigue crack growth behavior of Type 304 stainless steel, when the slow-fast type strain cycles were introduced into the repeat of fast-fast type strain cycle either in a periodical type (denoted as Type-I sequence) or in a block type (denoted as Type-II sequence), was investigated at the temperature of 873 K. It was found that an inertia accelerating phenomenon of crack growth rate occurred during the repeat of fast-fast type strain cycle, which followed the slow-fast type strain cycles introduced. It was also found that the above inertia accelerating phenomenon led to the significantly shorter fatigue crack propagation life than that evaluated from the linear damage summation rule, especially in the Type-I sequence. The observations of the longitudinal section through the specimen and the distribution of Vickers hardness suggested that a creep affected zone would be produced at the crack tip by the introduction of slow-fast type strain cycles, and it would cause the inertia acceleration of crack growth rate. In this work, the creep affected zone size, Rc was defined by the size of the region where the inertia acceleration of crack growth rate occurred. There was a linear relationship between Rc thus defined and the range of creep J-integral, which was produced just when the introduction of slow-fast type strain cycles was finished. Furthermore, based on the results thus obtained, the predicting method of crack growth rates both in the Type-I sequence and in the Type-II sequence was discussed.
Comments on “The Science and Applications of Acoustics” [Springer-Verlag (2000, 2006)]
Authors: Cunefare Kenneth A.
Published: October 2009

Raichel’s “The Science and Applications of Acoustics” (Springer-Verlag, Berlin, 2000) has extensive material that appears to have been extracted from four other texts without proper attribution. The material so used extends to figures, detailed structure of entire sections and developments, and phrasing of individual passages. While in some instances like material between the texts has been paraphrased to some extent, in others it appears almost unaltered.
Ranking vocal fold model parameters by their influence on modal frequencies
Authors: Cook Douglas D. , Nauman Eric , Mongeau Luc
Published: October 2009

The purpose of this study was to identify, using computational models, the vocal fold parameters which are most influential in determining the vibratory characteristics of the vocal folds. The sensitivities of vocal folds modal frequencies to variations model parameters were used to determine the most influential parameters. A detailed finite element model of the human vocal fold was created. The model was defined by eight geometric and six material parameters. The model included transitional boundary regions to idealize the complex physiological structure of real human subjects. Parameters were simultaneously varied over ranges representative of actual human vocal folds. Three separate statistical analysis techniques were used to identify the most and least sensitive model parameters with respect to modal frequency. The results from all three methods consistently suggest that a set of five parameters are most influential in determining the vibratory characteristics of the vocal folds.
Acoustic-articulatory mapping in vowels by locally weighted regression
Authors: McGowan Richard S. , Berger Michael A.
Published: October 2009

A method for mapping between simultaneously measured articulatory and acoustic data is proposed. The method uses principal components analysis on the articulatory and acoustic variables, and mapping between the domains by locally weighted linear regression, or loess [Cleveland, W. S. (1979). J. Am. Stat. Assoc. 74, 829–836]. The latter method permits local variation in the slopes of the linear regression, assuming that the function being approximated is smooth. The methodology is applied to vowels of four speakers in the Wisconsin X-ray Microbeam Speech Production Database, with formant analysis. Results are examined in terms of (1) examples of forward (articulation-to-acoustics) mappings and inverse mappings, (2) distributions of local slopes and constants, (3) examples of correlations among slopes and constants, (4) root-mean-square error, and (5) sensitivity of formant frequencies to articulatory change. It is shown that the results are qualitatively correct and that loess performs better than global regression. The forward mappings show different root-mean-square error properties than the inverse mappings indicating that this method is better suited for the forward mappings than the inverse mappings, at least for the data chosen for the current study. Some preliminary results on sensitivity of the first two formant frequencies to the two most important articulatory principal components are presented.
On the consideration of motion effects in the computation of impulse response for underwater acoustics inversion
Authors: Josso Nicolas F. , Ioana Cornel , Mars Jérôme I. , Gervaise Cédric , Stéphan Yann
Published: October 2009

The estimation of the impulse response (IR) of a propagation channel may be of great interest for a large number of underwater applications: underwater communications, sonar detection and localization, marine mammal monitoring, etc. It quantifies the distortions of the transmitted signal in the underwater channel and enables geoacoustic inversion. The propagating signal is usually subject to additional and undesirable distortions due to the motion of the transmitter-channel-receiver configuration. This paper shows the effects of the motion while estimating the IR by matched filtering between the transmitted and the received signals. A methodology to compare IR estimation with and without motion is presented. Based on this comparison, a method for motion effect compensation is proposed in order to reduce motion-induced distortions. The proposed methodology is applied to real data sets collected in 2007 by the Service Hydrographique et Océanographique de la Marine in a shallow water environment, proving its interest for motion effect analysis. Motion compensated estimation of IRs is computed from sources transmitting broadband linear frequency modulations moving at up to 12knots in the shallow water environment of the Malta plateau, South of Sicilia.
On the correlation of non-isotropically distributed ballistic scalar diffuse waves
Authors: Weaver Richard , Froment Berenice , Campillo Michel
Published: October 2009

Theorems indicating that a fully equipartitioned random wave field will have correlations equivalent to the Green’s function that would be obtained in an active measurement are now legion. Studies with seismic waves, ocean acoustics, and laboratory ultrasound have confirmed them. So motivated, seismologists have evaluated apparent seismic travel times in correlations of ambient seismic noise and tomographically constructed impressive maps of seismic wave velocity. Inasmuch as the random seismic waves used in these evaluations are usually not fully equipartitioned, it seems right to ask why it works so well, or even if the results are trustworthy. The error, in apparent travel time, due to non-isotropic specific intensity is evaluated here in a limit of large receiver-receiver separation and for the case in which the source of the noise is in the far field of both receivers. It is shown that the effect is small, even for cases in which one might have considered the anisotropy to be significant, and even for station pairs separated by as little as one or two wavelengths. A formula is derived that permits estimations of error and corrections to apparent travel time. It is successfully compared to errors seen in synthetic waveforms.
Time domain visualization using acoustic holography implemented by temporal and spatial complex envelope
Authors: Park Choon-Su , Kim Yang-Hann
Published: October 2009

Spatial envelope was proposed to show the location of acoustic sources and overall radiation pattern by the authors [C.-S. Park and Y.-H. Kim, J. Acoust. Soc. Am. 125, 206–211 (2009)]. The envelope can provide sufficient information on where the sources are and how the energy propagates into space. This concept is certainly useful for time domain acoustic holography since one can utilize not only spatial envelope to envisage what one needs to know but also temporal envelope to reduce the number of data. A holographic process to obtain spatial envelope is therefore introduced and verified, and how much one can reduce the processing time by implementing envelopes is compared with the conventional holography.
A three dimensional parabolic equation method for sound propagation in moving inhomogeneous media
Authors: Cheng Rui , Morris Philip J. , Brentner Kenneth S.
Published: October 2009

In this paper, a formulation of the Helmholtz equation for three dimensional sound propagation in a moving inhomogeneous medium in cylindrical coordinates is derived. Based on this formulation, a three dimensional parabolic equation (PE) is constructed. This PE can be used to model sound propagation in an inhomogeneous arbitrary moving medium. The method is used here to simulate three dimensional outdoor sound propagation above a rigid flat ground surface. The numerical results for two simple wind cases are presented and compared with analytical results to validate the methodology. Examples of propagation problems with more complicated wind are then included to demonstrate the importance of including the wind velocity directly in the PE method.
Acoustic standing wave suppression using randomized phase-shift-keying excitations
Authors: Tang Sai Chun , Clement Gregory T.
Published: October 2009

Recent papers have demonstrated that acoustic standing waves can be inhibited by frequency-modulated spread-spectrum excitation. An alternative method is studied here that is designed to be more practical for implementation in phased arrays. The method operates using phase-shift-keying (PSK), which introduces phase shifts into the driving signal to break wave symmetry. Sequential and random binary-PSK (BPSK) and quadrature-PSK (QPSK) excitations are studied in water, using a carrier frequency of 250kHz and a time segment of 10cycles. The resulting acoustic field is measured with a transducer inside a plastic-walled chamber and compared with continuous wave excitation. Results indicate that both the random BPSK and QPSK methods can reduce time-averaged spatial intensity variation caused by standing waves by approximately six times.