bluuebunny/crossref_metadata_2025 huggingface dataset:
Corrosion Protection Properties of Polyaniline–polypyrrole Composite Coatings on Al 2024
Authors: Shah K. , Zhu Y. , Iroh J.O. , Popoola O.
Published: May 2005

Polyaniline–polypyrrole composite coatings were deposited onto Al 2024 using an electrochemical process. The effect of incorporating inorganic fillers such as clay and yttria stabilised zirconia on the corrosion performance of the composite coating was studied. The coatings were analysed using infrared spectroscopy and scanning electron microscopy. The electrodeposition parameters such as feed monomer ratio, applied current density, and reaction time were systematically varied. Results showed that the composite coatings improved the corrosion resistance of the substrate.
Effect of weld metal copper content on HAZ cracking in austenitic stainless steel welded with Al brass
Authors: Lee H. W. , Sung J. H.
Published: May 2005

Austenitic stainless steel has good weldability but is sensitive to hot cracking such as solidification and liquation cracking. In the present study, specimens of dissimilar metals made from austenitic stainless steel and Al brass were welded by the GTAW process using four different filler metals. Cracks were detected in the heat affected zone of the stainless steel when welded with CuAl, CuSn and NiCu filler metals, but no cracks were detected when a Ni filler metal was used. The cracks propagated along the grain boundary in the heat affected zone near the fusion line to the base metal of 316L stainless steel. The cracks were located inside the weld bead with very fine hairline cracking. All cracks initiated at the fusion line and moved forward in the base metal. From energy dispersion spectroscopy (EDS), the Cu peak was detected only in the crack-opening area.
Modelling heat flow around tool probe in friction stir welding
Authors: Schmidt H. , Hattel J.
Published: May 2005

The objective of the present paper is to investigate the effect of including the tool probe in the numerical modelling of three-dimensional heat flow in friction stir welding (FSW). The heat flow close to the probe/matrix interface is investigated. In the models presented, the heat is forced to flow around the ‘probe hole’. In this manner, the material flow through the probe region, which often characterises other thermal models of FSW, is avoided. This necessitates controlling the convective heat flow by prescribing the velocity field in the narrow shear layer at the tool/matrix interface. As a consequence the sliding, sticking, or partial sliding/sticking condition can be modelled. Six cases are established, which are represented by three stages of refinement of the heat source model, combined with two different contact conditions, i.e. full sliding and full sticking.
Relationships between weld parameters, hardness distribution and temperature history in alloy 7050 friction stir welds
Authors: Reynolds A. P. , Tang W. , Khandkar Z. , Khan J. A. , Lindner K.
Published: May 2005

Aluminium alloy 7050 was friction stir welded using three different ratios of tool rotation rate to weld travel speed. Welds were made using travel speeds of between 0·85 and 5·1 mm s−1. Weld power and torque were recorded for each weld. An FEM simulation was used to calculate the time–temperature history for a subset of the welds. For each weld the hardness distribution with and without post-weld heat treatment was determined. The hardness distributions within the welds are rationalised based on the friction stir welding parameters and the resulting temperature histories. The analysis provides a basis for manipulation of weld parameters to achieve desired properties.
Determination of lower bound fracture toughness of a high strength low alloy steel welded joint
Authors: Gubeljak Nenad
Published: May 2005

The use of high strength low alloy steels for high performance structures (e.g. pressure vessels and pipelines) requires high strength consumables to produce an overmatched welded joint. This globally overmatched multipass welded joint contains two significantly different microstructures, as-welded and reheated. In this paper, the influence of weld metal microstructure on fracture behaviour is estimated in comparison with the fracture behaviour of composite microstructures (as-welded and reheated). The lower bound of fracture toughness for different microstructures was evaluated by using the modified Weibull distribution. The results, obtained using specimens with crack front through the thickness, indicated low fracture toughness, caused by strength mismatching interaction along the crack front. In the case of through thickness specimens, at least one local brittle microstructure is incorporated in the process zone at the vicinity of the crack tip. Hence, unstable fracture occurred with small, or without, stable crack propagation. Despite the fact that the differences between the impact toughness of a weld metal and the that of base metal are insignificant, the fracture toughness of a weld metal can be significantly lower.
Effect of rosuvastatin on outcomes in chronic haemodialysis patients – design and rationale of the AURORA study
Authors: Fellström Bengt , Zannad Faiez , Schmieder Roland , Holdaas Hallvard , Jardine Alan , Rose Helen , Wilpshaar Wim ,   the AURORA Study Group
Published: May 2005

Background

Patients with end-stage renal disease (ESRD) are at high risk of cardiovascular events. Multiple risk factors for atherosclerosis are present in ESRD and may contribute to the increased risk of cardiovascular mortality in this population. In contrast to patients with normal renal function, the benefits of modifying lipid levels on cardiovascular outcomes in patients with ESRD on haemodialysis have yet to be confirmed in large prospective randomised trials. A study to evaluate the Use of Rosuvastatin in subjects On Regular haemodialysis: an Assessment of survival and cardiovascular events (AURORA) will be the first large-scale international trial to assess the effects of statin therapy on cardiovascular morbidity and mortality in ESRD patients on chronic haemodialysis.

Methods

More than 2,750 ESRD patients who have been receiving chronic haemodialysis treatment for at least 3 months have been randomised (1:1), irrespective of baseline lipid levels, to treatment with rosuvastatin 10 mg or placebo. The primary study endpoint is the time to a major cardiovascular event (first occurrence of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke). Secondary endpoints include all-cause mortality, major cardiovascular event-free survival time, time to cardiovascular death, time to non-cardiovascular death, cardiovascular interventions, tolerability of treatment and health economic costs per life-year saved. Study medication will be given until 620 subjects have experienced a major cardiovascular event.

Conclusion

Our hypothesis is that results from AURORA will establish the clinical efficacy and tolerability of rosuvastatin in patients with ESRD receiving chronic haemodialysis and guide the optimal management of this expanding population.
Text Detective: a rule-based system for gene annotation in biomedical texts
Authors: Tamames Javier
Published: May 2005

Background

The identification of mentions of gene or gene products in biomedical texts is a critical step in the development of text mining applications in biosciences. The complexity and ambiguity of gene nomenclature makes this a very difficult task.

Methods

Here we present a novel approach based on a combination of carefully designed rules and several lexicons of biological concepts, implemented in the Text Detective system. Text Detective is able to normalize the results of gene mentions found by offering the appropriate database reference.

Results

In BioCreAtIvE evaluation, Text Detective achieved results of 84% precision, 71% recall for task 1A, and 79% precision, 71% recall for mouse genes in task 1B.
Overview of BioCreAtIvE task 1B: normalized gene lists
Authors: Hirschman Lynette , Colosimo Marc , Morgan Alexander , Yeh Alexander
Published: May 2005

Background

Our goal in BioCreAtIve has been to assess the state of the art in text mining, with emphasis on applications that reflect real biological applications, e.g., the curation process for model organism databases. This paper summarizes the BioCreAtIvE task 1B, the "Normalized Gene List" task, which was inspired by the gene list supplied for each curated paper in a model organism database. The task was to produce the correct list of unique gene identifiers for the genes and gene products mentioned in sets of abstracts from three model organisms (Yeast, Fly, and Mouse).

Results

Eight groups fielded systems for three data sets (Yeast, Fly, and Mouse). For Yeast, the top scoring system (out of 15) achieved 0.92 F-measure (harmonic mean of precision and recall); for Mouse and Fly, the task was more difficult, due to larger numbers of genes, more ambiguity in the gene naming conventions (particularly for Fly), and complex gene names (for Mouse). For Fly, the top F-measure was 0.82 out of 11 systems and for Mouse, it was 0.79 out of 16 systems.

Conclusion

This assessment demonstrates that multiple groups were able to perform a real biological task across a range of organisms. The performance was dependent on the organism, and specifically on the naming conventions associated with each organism. These results hold out promise that the technology can provide partial automation of the curation process in the near future.
Learning Statistical Models for Annotating Proteins with Function Information using Biomedical Text
Authors: Ray Soumya , Craven Mark
Published: May 2005

Background

The BioCreative text mining evaluation investigated the application of text mining methods to the task of automatically extracting information from text in biomedical research articles. We participated in Task 2 of the evaluation. For this task, we built a system to automatically annotate a given protein with codes from the Gene Ontology (GO) using the text of an article from the biomedical literature as evidence.

Methods

Our system relies on simple statistical analyses of the full text article provided. We learn n-gram models for each GO code using statistical methods and use these models to hypothesize annotations. We also learn a set of Naïve Bayes models that identify textual clues of possible connections between the given protein and a hypothesized annotation. These models are used to filter and rank the predictions of the n-gram models.

Results

We report experiments evaluating the utility of various components of our system on a set of data held out during development, and experiments evaluating the utility of external data sources that we used to learn our models. Finally, we report our evaluation results from the BioCreative organizers.

Conclusion

We observe that, on the test data, our system performs quite well relative to the other systems submitted to the evaluation. From other experiments on the held-out data, we observe that (i) the Naïve Bayes models were effective in filtering and ranking the initially hypothesized annotations, and (ii) our learned models were significantly more accurate when external data sources were used during learning.
Protein annotation as term categorization in the gene ontology using word proximity networks
Authors: Verspoor Karin , Cohn Judith , Joslyn Cliff , Mniszewski Sue , Rechtsteiner Andreas , Rocha Luis M , Simas Tiago
Published: May 2005

Background

We participated in the BioCreAtIvE Task 2, which addressed the annotation of proteins into the Gene Ontology (GO) based on the text of a given document and the selection of evidence text from the document justifying that annotation. We approached the task utilizing several combinations of two distinct methods: an unsupervised algorithm for expanding words associated with GO nodes, and an annotation methodology which treats annotation as categorization of terms from a protein's document neighborhood into the GO.

Results

The evaluation results indicate that the method for expanding words associated with GO nodes is quite powerful; we were able to successfully select appropriate evidence text for a given annotation in 38% of Task 2.1 queries by building on this method. The term categorization methodology achieved a precision of 16% for annotation within the correct extended family in Task 2.2, though we show through subsequent analysis that this can be improved with a different parameter setting. Our architecture proved not to be very successful on the evidence text component of the task, in the configuration used to generate the submitted results.

Conclusion

The initial results show promise for both of the methods we explored, and we are planning to integrate the methods more closely to achieve better results overall.
Exploring the boundaries: gene and protein identification in biomedical text
Authors: Finkel Jenny , Dingare Shipra , Manning Christopher D , Nissim Malvina , Alex Beatrice , Grover Claire
Published: May 2005

Background

Good automatic information extraction tools offer hope for automatic processing of the exploding biomedical literature, and successful named entity recognition is a key component for such tools.

Methods

We present a maximum-entropy based system incorporating a diverse set of features for identifying gene and protein names in biomedical abstracts.

Results

This system was entered in the BioCreative comparative evaluation and achieved a precision of 0.83 and recall of 0.84 in the "open" evaluation and a precision of 0.78 and recall of 0.85 in the "closed" evaluation.

Conclusion

Central contributions are rich use of features derived from the training data at multiple levels of granularity, a focus on correctly identifying entity boundaries, and the innovative use of several external knowledge sources including full MEDLINE abstracts and web searches.
Recognition of protein/gene names from text using an ensemble of classifiers
Authors: Zhou GuoDong , Shen Dan , Zhang Jie , Su Jian , Tan SoonHeng
Published: May 2005

This paper proposes an ensemble of classifiers for biomedical name recognition in which three classifiers, one Support Vector Machine and two discriminative Hidden Markov Models, are combined effectively using a simple majority voting strategy. In addition, we incorporate three post-processing modules, including an abbreviation resolution module, a protein/gene name refinement module and a simple dictionary matching module, into the system to further improve the performance. Evaluation shows that our system achieves the best performance from among 10 systems with a balanced F-measure of 82.58 on the closed evaluation of the BioCreative protein/gene name recognitiontask (Task 1A).
Gene/protein name recognition based on support vector machine using dictionary as features
Authors: Mitsumori Tomohiro , Fation Sevrani , Murata Masaki , Doi Kouichi , Doi Hirohumi
Published: May 2005

Background

Automated information extraction from biomedical literature is important because a vast amount of biomedical literature has been published. Recognition of the biomedical named entities is the first step in information extraction. We developed an automated recognition system based on the SVM algorithm and evaluated it in Task 1.A of BioCreAtIvE, a competition for automated gene/protein name recognition.

Results

In the work presented here, our recognition system uses the feature set of the word, the part-of-speech (POS), the orthography, the prefix, the suffix, and the preceding class. We call these features "internal resource features", i.e., features that can be found in the training data. Additionally, we consider the features of matching against dictionaries to be external resource features. We investigated and evaluated the effect of these features as well as the effect of tuning the parameters of the SVM algorithm. We found that the dictionary matching features contributed slightly to the improvement in the performance of the f-score. We attribute this to the possibility that the dictionary matching features might overlap with other features in the current multiple feature setting.

Conclusion

During SVM learning, each feature alone had a marginally positive effect on system performance. This supports the fact that the SVM algorithm is robust on the high dimensionality of the feature vector space and means that feature selection is not required.
Do orthologous gene phylogenies really support tree-thinking?
Authors: Bapteste E , Susko E , Leigh J , MacLeod D , Charlebois RL , Doolittle WF
Published: May 2005

Background

Since Darwin's Origin of Species, reconstructing the Tree of Life has been a goal of evolutionists, and tree-thinking has become a major concept of evolutionary biology. Practically, building the Tree of Life has proven to be tedious. Too few morphological characters are useful for conducting conclusive phylogenetic analyses at the highest taxonomic level. Consequently, molecular sequences (genes, proteins, and genomes) likely constitute the only useful characters for constructing a phylogeny of all life. For this reason, tree-makers expect a lot from gene comparisons. The simultaneous study of the largest number of molecular markers possible is sometimes considered to be one of the best solutions in reconstructing the genealogy of organisms. This conclusion is a direct consequence of tree-thinking: if gene inheritance conforms to a tree-like model of evolution, sampling more of these molecules will provide enough phylogenetic signal to build the Tree of Life. The selection of congruent markers is thus a fundamental step in simultaneous analysis of many genes.

Results

Heat map analyses were used to investigate the congruence of orthologues in four datasets (archaeal, bacterial, eukaryotic and alpha-proteobacterial). We conclude that we simply cannot determine if a large portion of the genes have a common history. In addition, none of these datasets can be considered free of lateral gene transfer.

Conclusion

Our phylogenetic analyses do not support tree-thinking. These results have important conceptual and practical implications. We argue that representations other than a tree should be investigated in this case because a non-critical concatenation of markers could be highly misleading.
An improved method for rapid generation of unmarked Pseudomonas aeruginosa deletion mutants
Authors: Choi Kyoung-Hee , Schweizer Herbert P
Published: May 2005

Background

Traditional gene replacement procedures are still time-consuming. They usually necessitate cloning of the gene to be mutated, insertional inactivation of the gene with an antibiotic resistance cassette and exchange of the plasmid-borne mutant allele with the bacterial chromosome. PCR and recombinational technologies can be exploited to substantially accelerate virtually all steps involved in the gene replacement process.

Results

We describe a method for rapid generation of unmarkedP. aeruginosadeletion mutants. Three partially overlapping DNA fragments are amplified and then spliced togetherin vitroby overlap extension PCR. The resulting DNA fragment is clonedin vitrointo the Gateway vector pDONR221 and then recombined into the Gateway-compatible gene replacement vector pEX18ApGW. The plasmid-borne deletions are next transferred to theP. aeruginosachromosome by homologous recombination. Unmarked deletion mutants are finally obtained by Flp-mediated excision of the antibiotic resistance marker. The method was applied to deletion of 25P. aeruginosagenes encoding transcriptional regulators of the GntR family.

Conclusion

While maintaining the key features of traditional gene replacement procedures, for example, suicide delivery vectors, antibiotic resistance selection and sucrose counterselection, the method described here is considerably faster due to streamlining of some of the key steps involved in the process, especially plasmid-borne mutant allele construction and its transfer into the target host. With appropriate modifications, the method should be applicable to other bacteria.
Personality disorders in substance abusers: Validation of the DIP-Q through principal components factor analysis and canonical correlation analysis
Authors: Hesse Morten
Published: May 2005

Background

Personality disorders are common in substance abusers. Self-report questionnaires that can aid in the assessment of personality disorders are commonly used in assessment, but are rarely validated.

Methods

The Danish DIP-Q as a measure of co-morbid personality disorders in substance abusers was validated through principal components factor analysis and canonical correlation analysis. A 4 components structure was constructed based on 238 protocols, representing antagonism, neuroticism, introversion and conscientiousness. The structure was compared with (a) a 4-factor solution from the DIP-Q in a sample of Swedish drug and alcohol abusers (N = 133), and (b) a consensus 4-components solution based on a meta-analysis of published correlation matrices of dimensional personality disorder scales.

Results

It was found that the 4-factor model of personality was congruent across the Danish and Swedish samples, and showed good congruence with the consensus model. A canonical correlation analysis was conducted on a subset of the Danish sample with staff ratings of pathology. Three factors that correlated highly between the two variable sets were found. These variables were highly similar to the three first factors from the principal components analysis, antagonism, neuroticism and introversion.

Conclusion

The findings support the validity of the DIP-Q as a measure of DSM-IV personality disorders in substance abusers.
A prospective cohort study of surgical treatment for back pain with degenerated discs; study protocol
Authors: Deyo Richard A , Mirza Sohail K , Heagerty Patrick J , Turner Judith A , Martin Brook I
Published: May 2005

Background

The diagnosis of discogenic back pain often leads to spinal fusion surgery and may partly explain the recent rapid increase in lumbar fusion operations in the United States. Little is known about how patients undergoing lumbar fusion compare in preoperative physical and psychological function to patients who have degenerative discs, but receive only non-surgical care.

Methods

Our group is implementing a multi-center prospective cohort study to compare patients with presumed discogenic pain who undergo lumbar fusion with those who have non-surgical care. We identify patients with predominant low back pain lasting at least six months, one or two-level disc degeneration confirmed by imaging, and a normal neurological exam. Patients are classified as surgical or non-surgical based on the treatment they receive during the six months following study enrollment.

Results

Three hundred patients discogenic low back pain will be followed in a prospective cohort study for two years. The primary outcome measure is the Modified Roland-Morris Disability Questionnaire at 24-months. We also evaluate several other dimensions of outcome, including pain, functional status, psychological distress, general well-being, and role disability.

Conclusion

The primary aim of this prospective cohort study is to better define the outcomes of lumbar fusion for discogenic back pain as it is practiced in the United States. We additionally aim to identify characteristics that result in better patient selection for surgery. Potential predictors include demographics, work and disability compensation status, initial symptom severity and duration, imaging results, functional status, and psychological distress.
Intermediate care: for better or worse? Process evaluation of an intermediate care model between a university hospital and a residential home
Authors: Plochg Thomas , Delnoij Diana MJ , van der Kruk Tineke F , Janmaat Tonnie ACM , Klazinga Niek S
Published: May 2005

Background

Intermediate care was developed in order to bridge acute, primary and social care, primarily for elderly persons with complex care needs. Such bridging initiatives are intended to reduce hospital stays and improve continuity of care. Although many models assume positive effects, it is often ambiguous what the benefits are and whether they can be transferred to other settings. This is due to the heterogeneity of intermediate care models and the variety of collaborating partners that set up such models. Quantitative evaluation captures only a limited series of generic structure, process and outcome parameters. More detailed information is needed to assess the dynamics of intermediate care delivery, and to find ways to improve the quality of care. Against this background, the functioning of a low intensity early discharge model of intermediate care set up in a residential home for patients released from an Amsterdam university hospital has been evaluated. The aim of this study was to produce knowledge for management to improve quality of care, and to provide more generalisable insights into the accumulated impact of such a model.

Methods

A process evaluation was carried out using quantitative and qualitative methods. Registration forms and patient questionnaires were used to quantify the patient population in the model. Statistical analysis encompassed T-tests and chi-squared test to assess significance. Semi-structured interviews were conducted with 21 staff members representing all disciplines working with the model. Interviews were transcribed and analysed using both 'open' and 'framework' approaches.

Results

Despite high expectations, there were significant problems. A heterogeneous patient population, a relatively unqualified staff and cultural differences between both collaborating partners impeded implementation and had an impact on the functioning of the model.

Conclusion

We concluded that setting up a low intensity early discharge model of intermediate care between a university hospital and a residential home is less straightforward than was originally perceived by management, and that quality of care needs careful monitoring to ensure the change is for the better.
Quantification of HTLV-I proviral load in experimentally infected rabbits
Authors: Zhao Tong-Mao , Hague Bishop , Caudell David L , Simpson R Mark , Kindt Thomas J
Published: May 2005

Background

Levels of proviral load in HTLV-1 infected patients correlate with clinical outcome and are reasonably prognostic. Adaptation of proviral load measurement techniques is examined here for use in an experimental rabbit model of HTLV-1 infection. Initial efforts sought to correlate proviral load with route and dose of inoculation and with clinical outcome in this model. These methods contribute to our continuing goal of using the model to test treatments that alleviate virus infection.

Results

A real-time PCR assay was used to measure proviral load in blood and tissue samples from a series of rabbits infected using HTLV-1 inocula prepared as either cell-free virus particles, infected cells or blood, or by naked DNA injection. Proviral loads from asymptomatically infected rabbits showed levels corresponding to those reported for human patients with clinically silent HTLV-1 infections. Proviral load was comparably increased in 50% of experimentally infected rabbits that developed either spontaneous benign or malignant tumors while infected. Similarly elevated provirus was found in organs of rabbits with experimentally induced acute leukemia/lymphoma-like disease. Levels of provirus in organs taken at necropsy varied widely suggesting that reservoirs of infections exist in non-lymphoid organs not traditionally thought to be targets for HTLV-1.

Conclusion

Proviral load measurement is a valuable enhancement to the rabbit model for HTLV-1 infection providing a metric to monitor clinical status of the infected animals as well as a means for the testing of treatment to combat infection. In some cases proviral load in blood did not reflect organ proviral levels, revealing a limitation of this method for monitoring health status of HTLV-1 infected individuals.
Quality of Life Outcomes From a Randomized Phase III Trial of Cisplatin With or Without Topotecan in Advanced Carcinoma of the Cervix: A Gynecologic Oncology Group Study
Authors: Monk Bradley J. , Huang Helen Q. , Cella David , Long Harry J.
Published: May 2005

Purpose

To prospectively assess the impact of treatment with cisplatin alone or in combination with topotecan (CT) on quality of life (QOL) in patients with advanced or recurrent cervical cancer, and to explore the prognostic value of baseline QOL scores.

Patients and Methods

Patients entered on Gynecologic Oncology Group (GOG) Protocol 179 were expected to complete QOL assessments at four time points using Functional Assessment of Cancer Therapy–General (FACT-G), Cervix subscale (Cx subscale), FACT/GOG–Neurotoxicity subscale (NTX subscale), Brief Pain Inventory (BPI), and UNISCALE (UNI). Adjusting for patient age, baseline scores, and effects of time, we longitudinally examined treatment effect on QOL during and after chemotherapy.

Results

Among patients randomly allocated to receive cisplatin (n = 146) or CT (n = 147), there were no statistically significant differences in QOL up to 9 months after randomization despite more hematologic toxicity in the combination arm. QOL assessments were completed at rates of 98%, 85%, 68%, and 59%, respectively, for the four time points, with similar rates and reasons for nonparticipation between regimens. Baseline FACT-G (P = .0016) and BPI (P = .0001) scores were significantly associated with patient age; older patients had better QOL and less pain. Baseline UNI was positively correlated with FACT-G (r = 0.66; P < .001) and Cx subscale (r = 0.29; P < .001), and negatively related to BPI (r = −0.41; P < .0001). Baseline FACT-Cx (FACT-G + Cx subscale) was associated with survival.

Conclusion

Despite increased toxicity, CT did not significantly reduce patient QOL when compared with cisplatin alone. Patient-reported QOL measures may be an important prognostic tool in advanced cervix cancer.
Using ultrasound to understand vascular and mantle contributions to venous return in the cephalopodSepia officinalisL.
Authors: King Alison J. , Henderson Stephen M. , Schmidt Matthias H. , Cole Alison G. , Adamo Shelley A.
Published: May 2005

Using ultrasound imaging, we investigated the roles of the potentially contractile veins and of the mantle (the powerful body wall that moves water over the gills, and also encloses the large veins and the hearts) in returning the blood of cuttlefish to its hearts. Ultrasound provided the first non-invasive observations of vascular function in an unanaesthetized,free-moving cephalopod. The large veins (anterior vena cava, lateral venae cavae and efferent branchial vessels) contracted in live, intact cuttlefish(Sepia officinalis L.). The anterior vena cava contracted at the same rate as the mantle, but it often expanded during mantle contraction. Furthermore, the anterior vena cava contracted peristaltically in vivo, suggesting that it actively aids venous return. The lateral venae cavae and efferent branchial vessels contracted at the same rate as the branchial and systemic hearts, but at a different rate from the mantle. A peristaltic wave appeared to travel along the lateral venae cavae to the branchial hearts, potentially aiding venous return. We found a muscular valve between the anterior and lateral venae cavae, which ensured that blood flowed only one way between these unsynchronized vessels. The mantle appears to have an unclear connection with cardiovascular function. We conclude that, when cuttlefish are at rest, the mantle does not compress any of the large veins that we imaged (including the anterior vena cava), and that peristaltic contractions of the large veins might be important in returning cephalopod blood to the hearts.
Scaling of suction-feeding kinematics and dynamics in the African catfish,Clarias gariepinus
Authors: Van Wassenbergh Sam , Aerts Peter , Herrel Anthony
Published: May 2005

Scaling effects on the kinematics of suction feeding in fish remain poorly understood, at least partly because of the inconsistency of the results of the existing experimental studies. Suction feeding is mechanically distinct from most other type of movements in that negative pressure inside the buccal cavity is thought to be the most important speed-limiting factor during suction. However, how buccal pressure changes with size and how this influences the speed of buccal expansion is unknown. In this paper, the effects of changes in body size on kinematics of suction feeding are studied in the catfish Clarias gariepinus. Video recordings of prey-capturing C. gariepinus ranging in total length from 111 to 923 mm were made,from which maximal displacements, velocities and accelerations of several elements of the cranial system were determined. By modelling the observed expanding head of C. gariepinus as a series of expanding hollow elliptical cylinders, buccal pressure and power requirement for the expansive phase of prey capture were calculated for an ontogenetic sequence of catfish. We found that angular velocities decrease approximately proportional with increasing cranial size, while linear velocities remain more or less constant. Although a decreasing (angular) speed of buccal expansion with increasing size could be predicted (based on calculations of power requirement and the expected mass-proportional scaling of available muscular power in C. gariepinus), the observed drop in (angular) speed during growth exceeds these predictions. The calculated muscle-mass-specific power output decreases significantly with size, suggesting a relatively lower suction effort in the larger catfish compared with the smaller catfish.
The role of myostatin and the calcineurin-signalling pathway in regulating muscle mass in response to exercise training in the rainbow troutOncorhynchus mykissWalbaum
Authors: Martin C. I. , Johnston I. A.
Published: May 2005

Rainbow trout Oncorhynchus mykiss Walbaum were exercised at 0.8 and 1.6 body lengths s-1 for 18 h a day over a 30 day period. Exercise resulted in a 24-30% increase in the average cross-sectional area of fast muscle fibres relative to tank-rested controls. The concentrations of growth factors and transcription factors hypothesised to play a role in regulating exercise-induced muscle fibre hypertrophy were measured. Exercise training resulted in a minor increase in calcineurin localisation in the nucleus. However, nuclear factor of T-cells 2 (NFAT2) nuclear localisation did not follow a pattern that was consistent with NFAT2-mediated transcriptional activity and changes in calcineurin signaling. The active peptide of myostatin, a negative regulator of muscle growth in mammals, was downregulated in exercise groups relative to tank-rested controls, but only by 6-7%. It was concluded that myostatin and calcineurin signaling do not play a major role in regulating exercise-induced muscle hypertrophy in trout.
Cardiac performance in the zebrafishbreakdancemutant
Authors: Kopp Renate , Schwerte Thorsten , Pelster Bernd
Published: May 2005

In the Tübingen screen a breakdance mutant of zebrafish(bre) was described as an arrhythmia, in which the ventricle beats only with every second atrial contraction (2:1 rhythm). Surprisingly, a careful analysis of the effect of the breakdance mutation on cardiac performance of the zebrafish during development between 3 d.p.f. and 14 d.p.f revealed that homozygous bre mutants did not always show the 2:1 rhythm. Cardiac activity was continuously recorded for a period of 20 min in each larva, and during this period we observed that heart rate randomly switched between the 2:1 rhythm and a 1:1 rhythm. Furthermore, at 28°C and at 31°C the expression of the 2:1 rhythm decreased with development. At 31°C this was in part due to a significantly reduced survival rate of mutants beyond 4 d.p.f. Besides development, temperature had a marked effect on the expression of the 2:1 rhythm, and during the first days of development the expression of the 2:1 rhythm was significantly higher at elevated incubation temperatures. By contrast, in the 2:1 beating heart ventricular contraction rate was about 80 beats min-1 throughout development irrespective of the temperature, and even in the 1:1 rhythm mutants showed a significant bradycardia at all three temperatures (25°C, 28°C or 31°C). Compared to wild-type animals, cardiac output was significantly lower in bre mutants. Pressure traces recorded in the ventricle of mutants revealed a prolonged relaxation phase, indicating that the second pacemaker current could not be conveyed to the ventricle (AV-block). This phenotype is comparable to the human Long QT Syndrome, an arrhythmia caused by a modification of an ion channel involved in cardiac repolarization. The bradycardia and the modified temperature sensitivity of heart rate suggested that the activity of the pacemaker cells was also affected by this mutation.
Interaction between facilitation and presynaptic inhibition at the crayfish neuromuscular junction
Authors: DeMill Colin M. , Delaney Kerry R.
Published: May 2005

Action potential-mediated calcium (Ca) entry into excitor nerve terminal boutons during presynaptic inhibition and the effects of co-activation of the inhibitor on the kinetics of muscle contraction were studied at crayfish claw opener muscle. Inhibition reduced postsynaptic excitatory junction potentials(EJPs) below the threshold to initiate contraction. Upon cessation of inhibition, EJP amplitudes immediately increased several-fold due to the build-up of presynaptic facilitation during inhibition. Consequently, muscle contraction was initiated more rapidly after a period of inhibitor-excitor coactivation.

Presynaptic inhibition reduced Ca entry into presynaptic excitor terminal boutons (range 0-50%, mean ± s.e.m.=20±1%, N=122 terminals; 12 preparations) and reduced the EJP amplitude (range 30-70%, mean± s.e.m.=51±2%, N=27 cells). The decline in the EJP was proportional to the reduction of Ca influx raised to the power of 2.8. Since presynaptic inhibition reduces the number of Ca channels opened by an action potential, our data suggest cooperativity between Ca channel microdomains to initiate vesicle fusion at this synapse.

The amount of inhibition of Ca influx into an excitor bouton was not correlated with either the distance to the closest inhibitor bouton or the main excitor branch, although slightly more inhibition was seen for excitor boutons on tertiary versus secondary branches. Unlike inhibitor axon stimulation, bath application of GABA caused inhibition of Ca influx that steadily increased from proximal to distal terminal boutons on a branch. We propose a model where presynaptic inhibition causes localized shunting of an actively propagated action potential in the vicinity of release sites, which can recover its amplitude outside the shunted region.
End-game guidance laws for dual-control missiles
Authors: Shima T , Golan O M
Published: May 2005

New guidance laws derived for a dual-control missile are studied. Their performance is compared with that of a conventional guidance system with flight control that distributes the commands among the two control channels. A Monte Carlo simulation study is performed where the target executes random evasive manoeuvres. The interceptor, represented by linear high-order manoeuvring dynamics with bounded forward and aft controls, acquires noisy measurements and uses a state estimator. Using the single-shot kill probability as a performance criterion, the superiority of the new guidance and control architecture is shown. It is also shown that the best performance is obtained by the bounded controls differential game guidance law. Sensitivity to the selection of the interceptor first-order time constant, a design parameter in the guidance law derivation, is also investigated.
Improved estimation is a prerequisite for successful terminal guidance
Authors: Shinar J , Turetsky V
Published: May 2005

Successful interception of manoeuvring anti-surface missiles that are expected in the future can be achieved only if the estimation errors against manoeuvring targets can be minimized. The paper raises new ideas for an improved estimation concept by separating the tasks of the estimation system and by explicit use of the time-to-go in the process. The outcome of the new approach is illustrated by results of Monte Carlo simulations in generic interception scenarios. The results indicate that if an eventual ‘jump’ in the commanded target acceleration is detected sufficiently rapidly, small estimation errors and consequently precise guidance can be obtained.
Non-linear missile guidance synthesis using control Lyapunov functions
Authors: Gurfil P
Published: May 2005

This paper derives a new non-linear guidance law aimed at interception of highly manoeuvring targets. The guidance law is developed based on the theory of control Lyapunov functions (CLFs), a methodology for universal stabilization of non-linear systems which is also inverse optimal with respect to some performance measure. The three-dimensional guidance dynamics are formulated in a fixed-line-of-sight coordinate system, yielding matching between the target and missile accelerations. Closed-form expressions for the CLF guidance commands are given. Simulation shows that the new guidance scheme significantly outperforms augmented proportional navigation in short-range engagements.
Synthesis of Tb3+-doped ZnO Nanowire Arrays Through a Facile Sol–Gel Template Approach
Authors: Yang Lei , Li Yan , Xiao Yanhe , Ye Changhui , Zhang Lide
Published: May 2005

Ordered Tb3+-doped zinc oxide nanowire arrays embedded in anodic alumina membranes (AAM) were fabricated by an improved sol–gel method. They have hexagonal wurtzite structure with uniform diameter of about 30 nm and the Tb3+ ions occupy Zn sites or interstitial sites in the crystal. The emission spectra of ZnO:Tb consist of four main lines at 488 nm, 543 nm, 586 nm, and 622 nm under 377 nm excitation, among which the electric dipole transition 5D4 → 7F5 (at 543 nm) is the strongest.
Synthesis of 2-Pyridylpyridines via Aza-Diels–Alder Reactions between 3-Pyridyl-1,2,4-triazines and Some Vinyl Alkanoates
Authors: Shintou Taichi , Ikeuchi Fumiaki , Kuwabara Hirokazu , Umihara Ken , Itoh Isamu
Published: May 2005

New synthetic procedure for 2,ω-bipyridines involving aza-Diels–Alder reaction between 3-(ω-pyridyl)-1,2,4-triazine and vinyl octanoate or decanoate as a dienophile is described.
Infection of the surgical site after arthroplasty of the hip
Authors: Ridgeway S. , Wilson J. , Charlet A. , Kafatos G. , Pearson A. , Coello R.
Published: May 2005

We wished to estimate the incidence of surgical-site infection (SSI) after total hip replacement (THR) and hemiarthroplasty and its strength of association with major risk factors. The SSI surveillance service prospectively gathered clinical, operative and infection data on inpatients from 102 hospitals in England during a four-year period.

The overall incidence of SSI was 2.23% for 16 291 THRs, 4.97% for 5769 hemiarthroplasty procedures, 3.68% for 2550 revision THRs and 7.6% for 198 revision hemiarthroplasties. Staphylococcus aureus was identified in 50% of SSIs; 59% of these isolates were methicillin-resistant (MRSA). In the single variable analysis of THRs, age, female gender, American Society of Anesthesiologists (ASA) score, body mass index, trauma, duration of operation and pre-operative stay were significantly associated with the risk of SSI (p < 0.05). For hemiarthroplasty, the ASA score and age were significant factors. In revision THRs male gender, ASA score, trauma, wound class, duration of operation and pre-operative stay were significant risk factors. The median time to detection of SSI was eight days for superficial incisional, 11 days for deep incisional and 11 days for joint/bone infections. For each procedure the mean length of stay doubled for patients with SSI. The multivariate analysis identified age group, trauma, duration of operation and ASA score as significant, independent risk factors for SSI. There was significant interhospital variation in the rates of SSI. MRSA was the most common pathogen to cause SSI in hip arthroplasty, especially in patients undergoing hemiarthroplasty, but coagulase-negative Staph. aureus may be more important in deep infections involving the joint.
Ten-year results of a press-fit, porous-coated acetabular component
Authors: Grobler G. P. , Learmonth I. D. , Bernstein B. P. , Dower B. J.
Published: May 2005

We retrospectively reviewed, ten years after surgery, 100 consecutive total hip replacements in which the Duraloc 300 cup had been used. Post-operative radiographs were analysed for placement of the cup and interface gaps and follow-up radiographs for lucent lines, osteolysis, wear and migration.

All the components were found to be stable with no evidence of loosening. The mean rate of wear was 0.12 mm/year. Three hips developed acetabular osteolysis at the level of the apex hole. Two have successfully undergone bone grafting without removal of the implants and one patient is awaiting surgery. The Duraloc 300 cup has a survival of 100% at ten years with no aseptic loosening and a low incidence of pelvic osteolysis.
The biomechanical effect of radial shortening on the radiocapitellar articulation
Authors: Diab M. , Poston J. M. , Huber P. , Tencer A. F.
Published: May 2005

Repeated trauma to the radial head may be one of the causative factors in the genesis of osteochondritis dissecans of the capitellum. We measured the force, contact area and pressure across the radiocapitellar articulation of the elbow before and after radial shortening osteotomy in five fresh-frozen cadaver upper limbs with loads of 45, 90 and 135 N, respectively. Measurements were made on pressure-sensitive film placed in the radiocapitellar articulation with the forearm in the supinated, neutral and pronated positions before and after radial shortening. Radial shortening significantly reduced the mean force and contact area across the radiocapitellar articulation in all positions of the forearm.
Techniques for improving stability in oblique fractures treated by circular fixation with particular reference to the sagittal plane
Authors: Metcalfe A. J. , Saleh M. , Yang L.
Published: May 2005

Biomechanical studies involving all-wire and hybrid types of circular frame have shown that oblique tibial fractures remain unstable when they are loaded. We have assessed a range of techniques for enhancing the fixation of these fractures. Eight models were constructed using Sawbones tibiae and standard Sheffield ring fixators, to which six additional fixation techniques were applied sequentially.

The major component of displacement was shear along the obliquity of the fracture. This was the most sensitive to any change in the method of fixation. All additional fixation systems were found to reduce shear movement significantly, the most effective being push-pull wires and arched wires with a three-hole bend. Less effective systems included an additional half pin and arched wires with a shallower arc. Angled pins were more effective at reducing shear than transverse pins.

The choice of additional fixation should be made after consideration of both the amount of stability required and the practicalities of applying the method to a particular fracture.
Accuracy of CT arthrography in the assessment of tears of the rotator cuff
Authors: Charousset C. , Bellaïche L. , Duranthon L. D. , Grimberg J.
Published: May 2005

CT arthrography and arthroscopy were used to assess tears of the rotator cuff in 259 shoulders. Tear size was determined in the frontal and sagittal planes according to the classification of the French Arthroscopy Society.

CT arthrography had a sensitivity of 99% and a specificity of 100% for the diagnosis of tears of supraspinatus. For infraspinatus these figures were 97.44% and 99.52%, respectively and, for subscapularis, 64.71% and 98.17%. For lesions of the long head of the biceps, the sensitivity was 45.76% and the specificity was 99.57%.

Our study showed an excellent correlation between CT arthrography and arthroscopy when assessing the extent of a rotator cuff tear. CT arthrography should, therefore, be an indispensable part of pre-operative assessment. It allows determination of whether a tear is reparable (retraction of the tendon and fatty degeneration of the corresponding muscle) and whether this is possible by arthroscopy (degree of tendon retraction and extension to subscapularis).