bluuebunny/crossref_metadata_2025 huggingface dataset:
Tracking genomic instability within irradiated and bystander populations
Authors: Chapman Kim L , Kelly James W , Lee Ryonfa , Goodwin Edwin H , Kadhim Munira A
Published: July 2008

Over the past two decades, our understanding of radiation biology has undergone a fundamental shift in paradigms away from deterministic ‘hit-effect’ relationships and towards complex ongoing ‘cellular responses’. These responses include now familiar, but still poorly understood, phenomena associated with radiation exposure such as genomic instability and bystander effects. Although these responses share some common features (e.g. they occur at high frequency following very low doses, are heterogeneous in their induction and are observed at time points far removed from the initial radiation exposure), the precise relationship between genomic instability and bystander effects remains to be elucidated. This review will provide a synthesis of the known, and proposed, interrelationships among irradiated and bystander cellular responses to radiation. It also discusses our current experimental approach for gaining a clearer understanding of the relationship between damage induction and long-term effects in both irradiated and bystander cells.
Epidermal growth factor receptor inhibitors for radiotherapy: biological rationale and preclinical results
Authors: Zips Daniel , Krause Mechthild , Yaromina Ala , Dörfler Annegret , Eicheler Wolfgang , Schütze Christina , Gurtner Kristin , Baumann Michael
Published: July 2008

Blocking the epidermal growth factor receptor (EGFR) represents a role model for a successful biological targeting approach to improving outcomes after radiotherapy. This review summarizes data from several local tumour control experiments in which EGFR inhibitors were combined with radiation in FaDu human squamous cell carcinomas xenografted into nude mice. BIBX1382BS is an oral bioavailable inhibitor of the intracellular tyrosine kinase domain of EGFR. It was administered in different experimental settings: concurrent with fractionated radiotherapy, following completion of irradiation, and in the period between surgery and adjuvant irradiation. Despite beneficial effects on tumour growth, in none of these experimental settings did BIBX1382BS improve local tumour control. In contrast, cetuximab (Erbitux), an IgG1 monoclonal antibody against the extracellular ligand-binding domain of EGFR, improved local tumour control when given concurrently with radiation. Results from a series of local tumour control experiments designed to elucidate the underlying mechanisms of cetuximab suggest that multiple radiobiological mechanisms might contribute to the observed effects: decreased number of clonogenic tumour cells, increased cellular radiation sensitivity, decreased repopulation and improved reoxygenation of clonogenic tumour cells during the combined treatment. In summary, the data suggest that different classes of EGFR inhibitors may have a different potential to improve local tumour control after fractionated irradiation.
Amelioration of the pathological changes induced by radiotherapy in normal tissues
Authors: Rezvani Mohi
Published: July 2008

Damage to normal tissues remains the most important limiting factor in the treatment of cancer by radiotherapy. In order to deliver a radiation dose sufficient to eradicate a localised tumour, the normal tissues need to be protected. A number of pharmacological agents have been used experimentally, and some clinically, to alleviate radiation damage to normal tissues but at present there is no effective clinical treatment to protect normal tissues against radiation injury. This paper reviews the efficacy of pharmacological substances used after radiation exposure. The limited evidence available suggests that radiation insult, like many other tissue injuries, is amenable to pharmacological intervention. However, care must be taken in the administration of these substances for the management of different aspects of radiation damage because there appears to be a tissue-specific response to different pharmacological agents. Also, one must be aware of the limitations of results obtained from animal models, which do not necessarily correlate to benefits in the clinic; the conflicting results reported with some modifiers of radiation damage; and the toxicity of these substances and radiation doses used in published studies. Conflicting results may arise from differences in the pathophysiologic processes involved in the development of radiation lesions in different tissues, and in the markers used to assess the efficacy of treatment agents.
PEGylated nanostructured lipid carriers loaded with 10-hydroxycamptothecin: an efficient carrier with enhanced anti-tumour effects against lung cancer
Authors: Zhang Xinxin , Gan Yong , Gan Li , Nie Shufang , Pan Weisan
Published: July 2008

Most drugs do not have the pharmacokinetic features required for optimal pulmonary delivery. In this study, we developed PEGylated nanostructured lipid carriers (PEG-NLCs) to improve the delivery of anti-tumour agents to lung tumours. PEG-40 NLCs modified with PEG-40 stearate (molecular weight 2000 Da), PEG-100 NLCs modified with PEG-100 stearate (molecular weight 5000 Da) and NLCs without PEG modification were prepared by melt-emulsification and homogenization, and were loaded with 10-hydroxycamptothecin (HCPT). They were investigated in terms of physiological characteristics, biodistribution, cellular uptake, and anti-tumour effect in-vivo. PEG-NLCs exhibited regular morphology, with a spherical shape. The particle size (measured by laser diffraction) was approximately 100 nm. Encapsulation in PEG-NLCs protected the active lactone form of HCPT compared with HCPT solution after incubation with plasma. In biodistribution studies, PEG-NLCs, especially PEG-40 NLCs, had longer circulation time and decreased uptake by the reticuloendothelial system (RES) compared with unmodified NLCs. PEG-NLCs accumulated in the lungs after i.v. injection in mice. PEG-NLCs showed enhanced cellular uptake by human lung adenocarcinoma epithelial A549 cells. In-vivo experiments indicated that PEG-NLCs loaded with HCPT have superior efficacy against A549 lung cancer compared with HCPT solution and NLCs. These results suggest that PEG-NLCs is a promising delivery system for HCPT in the treatment of lung cancer.
Saying Good-Bye to the Direct Argument the Right Way
Authors: McKenna Michael
Published: July 2008

Peter van Inwagen contends that nonresponsibility transfers across deterministic relations. Suppose it does. If the facts of the past and the laws of nature entail every truth about what one does, and no one is even in part morally responsible for the past and the laws, then no one is even in part morally responsible for what one does. This argument, the Direct Argument, has drawn various critics, who have attempted to produce counterexamples to its core inference principle. This article considers two notable efforts, one by John Martin Fischer and Mark Ravizza and another by David Widerker. It shows that neither is sufficient to reject the Direct Argument. The article then proceeds to challenge the argument in a novel fashion. Van Inwagen has not given us good reason to think that the principle in question has an adequate anchor in our inferential practices, especially in light of the dialectical context with the compatibilist. Hence, it is not the compatibilists' burden to produce counterexamples to it. Rather, it is van Inwagen's burden to produce relevant confirming instances of it.
Pattern formation in the vertebrate neural tube: a sonic hedgehog morphogen-regulated transcriptional network
Authors: Dessaud Eric , McMahon Andrew P. , Briscoe James
Published: July 2008

Neuronal subtype specification in the vertebrate neural tube is one of the best-studied examples of embryonic pattern formation. Distinct neuronal subtypes are generated in a precise spatial order from progenitor cells according to their location along the anterior-posterior and dorsal-ventral axes. Underpinning this organization is a complex network of multiple extrinsic and intrinsic factors. This review focuses on the molecular mechanisms and general strategies at play in ventral regions of the forming spinal cord, where sonic hedgehog-based morphogen signaling is a key determinant. We discuss recent advances in our understanding of these events and highlight unresolved questions.
The role of the antennae during courtship behaviour in the parasitic waspTrichopria drosophilae
Authors: Romani Roberto , Rosi Marzia Cristiana , Isidoro Nunzio , Bin Ferdinando
Published: July 2008

We have studied the courtship behaviour of Trichopria drosophilaePerkins (Hymenoptera: Diapriidae), a pupal parasitoid of the common fruit fly Drosophila melanogaster Meigen (Diptera: Drosophilidae), to understand the role of the antennae. Virgin pairs of the parasitoid perform an intense and stereotyped antennal courtship, which leads to copulation. During antennation, the two male fourth antennomeres come into contact with the two apical female antennomeres, and thus the secretion produced by the sex pheromone gland is spread onto the female receptors. By preventing the transfer of the courtship pheromone from male to female antennae, mating was inhibited. Moreover, selective ablation of single antennae demonstrated that the courtship pheromone acts on contact. When antennae of both sexes were partially removed (ablation at the same side, i.e. right or left) courtship was successful and copulation occurred. In contrast, in the case of antennal ablation at opposite sides, courtship failed despite the short distance between secretion and receptors. These results confirm the hypothesis that T. drosophilae male antennal glands are the release site of a contact courtship pheromone, playing a key role in mating behaviour. The occurrence of male antennal glands in Hymenoptera and other insect orders is discussed.
Nitric oxide induces aspects of egg-laying behavior in Aplysia
Authors: Miller Nimrod , Katzoff Ayelet , Susswein Abraham J.
Published: July 2008

Aplysia egg laying is a complex behavior requiring synchronized activity in many organs. Aspects of the behavior are synchronized viathe direct effects of peptide bag cell neurohormones and via stimuli arising during the behavior. Stimuli synchronizing egg laying were examined by treating A. fasciata with a nitric oxide (NO) donor. NO elicited normal appetitive and consummatory behaviors leading to the deposition of cordons containing egg capsules without eggs. The sites at which NO acts were investigated. The latency to egg deposition in response to a NO donor was shorter than that in response to other stimuli, consistent with NO acting at downstream sites from those affected by the other stimuli. The NO donor does not act on neurons in the head ganglia presynaptic to the bag cells or on the bag cells. Ligating the small hermaphroditic duct connecting the gonad to the accessory genital mass blocked egg laying in response to bag cell homogenates,but not in response to exogenous NO, indicating that NO does not act on the gonad. NO is released by transport of eggs along the small hermaphroditic duct, and NO directly acts on the accessory genital mass which packages eggs. NO also acts at a second site, independent of the effect on the accessory genital mass. A NO donor activates appetitive behaviors that normally precede egg laying even in A. californica that are unable to lay eggs.
The neuroethology of song cessation in response to gleaning bat calls in two species of katydids,Neoconocephalus ensigerandAmblycorypha oblongifolia
Authors: ter Hofstede Hannah M. , Fullard James H.
Published: July 2008

We investigated whether the use of primary or secondary behavioural defences is related to prey sensory thresholds using two species of North American katydids, Neoconocephalus ensiger and Amblycorypha oblongifolia. Male katydids produce intense calling songs to attract mates, and many gleaning bat species are known to use these calls to locate them as prey. Low duty cycle calling (i.e. sporadic calls) is a primary defence against gleaning bats (prevents attacks), and song cessation is a secondary defence (enables survival of an attack), for which these two species show behavioural differences. Echolocation calls of Myotis septentrionalis, a sympatric gleaning bat species, were broadcast to singing katydids and to neural preparations of these katydids to test if differences in behavioural response were related to differences in auditory sensitivity. We measured thresholds and firing patterns of the T-cell, an auditory interneuron involved in predator detection. We hypothesized that low duty cycle calling is the best defence for species not sensitive enough to mount a secondary defence in response to predator cues; therefore, we predicted that N. ensiger (high duty cycle song) would have lower behavioural and T-cell thresholds than A. oblongifolia (low duty cycle song). Although more N. ensiger ceased singing than A. oblongifolia, the number and maximum firing rate of T-cell action potentials did not differ between species for echolocation call sequences. We suggest that the T-cell has divergent functions within the Tettigoniidae,including predator and mate detection, and the function could be context dependent in some species.
Experimental reduction of ultraviolet wavelengths reflected from parasitic eggs affects rejection behaviour in the blackcapSylvia atricapilla
Authors: Honza Marcel , Polačiková Lenka
Published: July 2008

Hosts of brood parasites use a variety of cues relating to eggshell appearance of parasitic eggs, which facilitate their recognition and rejection. It has been documented that host visual perception of different colours including UV wavelengths plays an important role in this respect. In the study reported here, we aimed to test whether artificial reduction of the UV wavelengths reflected from parasitic eggshell affects rejection behaviour in the blackcap Sylvia atricapilla. To achieve this goal, we experimentally manipulated, with UV, part of spectra reflected from conspecific eggs and reduced it into the range of 320–350 nm. We used an ultraviolet light blocker, which did not influence the reflectance shape of other spectrum parts. We also used a group of experimental eggs coated in Vaseline, which had no effect on the spectral shape in the UV or visible ranges of the light spectrum. Additionally, we used a third experimental group of unmanipulated eggs as a control. The experimental eggs coated in the UV blocker were rejected at a higher rate than those coated in the Vaseline. Moreover, a binary logistic regression revealed that an artificial reduction of the UV wavelengths reflected from the parasitic egg significantly affected the probability of being rejected by the hosts. To our knowledge, this is the first experimental study to reveal that manipulation with UV wavelengths affects the recognition of parasitic eggs, indicating that the UV part of the spectrum has an important role in host recognition behaviour.
Caste differences in venom volatiles and their effect on alarm behaviour in the paper waspPolistes dominulus (Christ)
Authors: Bruschini Claudia , Cervo Rita , Protti Ilaria , Turillazzi Stefano
Published: July 2008

Foundresses and workers of Polistes paper wasps show slight morphological and physiological differences. However, after the emergence of the workers, the castes can be readily discriminated by their behaviour: the dominant foundress is the principal egg-layer, whereas workers perform different tasks linked to colony development. Previous studies have demonstrated in this genus that defence of the colony by the workers is more effectively carried out by a collective response elicited by venom volatiles used as alarm pheromones. In the present study, gas chromatography–mass spectrometry analyses of the venom volatiles of foundresses and workers of Polistes dominulus (Christ) show predominantly quantitative differences. Spiroacetals, mainly(E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, are significantly higher in the venom volatiles fraction of workers, whereas the amount of N-(3-methylbutyl)acetamide is almost double in foundresses. On the basis of the chemical results, behavioural assays were performed on fifteen field colonies to test the alarm response of the resident wasps to venom extracts from foundresses and workers. Our behavioural results suggest that worker venom has a stronger alarm effect on the colonies than that of the foundresses, which seems unable to elicit the complete alarm response ending with a final attack and sting. The venom volatiles of P. dominulusworkers serve mainly to alarm the colony whilst those of foundresses may also be linked to additional functions related to conspecific interactions.
Physiological and molecular mechanisms of osmoregulatory plasticity in killifish after seawater transfer
Authors: Scott Graham R. , Baker Daniel W. , Schulte Patricia M. , Wood Chris M.
Published: July 2008

We have explored the molecular and physiological responses of the euryhaline killifish Fundulus heteroclitus to transfer from brackish water (10% seawater) to 100% seawater for 12 h, 3 days or 7 days. Plasma[Na+] and [Cl–] were unchanged after transfer, and plasma cortisol underwent a transient increase. Na+/K+-ATPase activity increased 1.5-fold in the gills and opercular epithelium at 7 days (significant in gills only), responses that were preceded by three- to fourfold increases in Na+/K+-ATPase α1a mRNA expression. Expression of Na+/K+/2Cl– cotransporter 1, cystic fibrosis transmembrane conductance regulator (CFTR)Cl– channel, Na+/H+-exchanger 3(significant in opercular epithelium only) and carbonic anhydrase II mRNA also increased two- to fourfold after transfer. Drinking rate increased over twofold after 12 h and remained elevated for at least 7 days. Surprisingly,net rates of water and ion absorption measured in vitro across isolated intestines decreased ∼50%, possibly due to reduced salt demands from the diet in seawater, but water absorption capacity still exceeded the drinking rate. Changes in bulk water absorption were well correlated with net ion absorption, and indicated that slightly hyperosmotic solutions (⩾298 mmol l–1) were transported. There were no reductions in unidirectional influx of Na+ from luminal to serosal fluid or intestinal Na+/K+-ATPase activity after transfer. Overall, our results indicate that gill and opercular epithelia function similarly at a molecular level in seawater, in contrast to their divergent function in freshwater, and reveal unexpected changes in intestinal function. As such they provide further insight into the mechanisms of euryhalinity in killifish.
Sexual dimorphism in auditory mechanics: tympanal vibrations ofCicada orni
Authors: Sueur Jérôme , Windmill James F. C. , Robert Daniel
Published: July 2008

In cicadas, the tympanum is anatomically intricate and employs complex vibrations as a mechanism for auditory frequency analysis. Using microscanning laser Doppler vibrometry, the tympanal mechanics of Cicada orni can be characterized in controlled acoustical conditions. The tympanum of C. orni moves following a simple drum-like motion, rather than the travelling wave found in a previous study of Cicadatra atra. There is a clear sexual dimorphism in the tympanal mechanics. The large male tympanum is unexpectedly insensitive to the dominant frequency of its own calling song,possibly a reflection of its dual purpose as a sound emitter and receiver. The small female tympanum appears to be mechanically sensitive to the dominant frequency of the male calling song and to high-frequency sound, a capacity never suspected before in these insects. This sexual dimorphism probably results from a set of selective pressures acting in divergent directions,which are linked to the different role of the sexes in sound reception and production. These discoveries serve to indicate that there is far more to be learnt about the development of the cicada ear, its biomechanics and evolution, and the cicada's acoustic behaviour.
In vivostrains in the femur of river cooter turtles(Pseudemys concinna) during terrestrial locomotion: tests of force-platform models of loading mechanics
Authors: Butcher Michael T. , Espinoza Nora R. , Cirilo Stephanie R. , Blob Richard W.
Published: July 2008

Previous analyses of ground reaction force (GRF) and kinematic data from river cooter turtles (Pseudemys concinna) during terrestrial walking led to three primary conclusions about the mechanics of limb bone loading in this lineage: (1) the femur was loaded in a combination of axial compression,bending and torsion, similar to previously studied non-avian reptiles, (2)femoral shear stresses were high despite the possession of a reduced tail in turtles that does not drag on the ground and (3) stress-based calculations of femoral safety factors indicated high values in bending and torsion, similar to other reptiles and suggesting that substantial `overbuilding' of limb bones could be an ancestral feature of tetrapods. Because force-platform analyses produce indirect estimates of bone loading, we sought to validate these conclusions by surgically implanting strain gauges on turtle femora to directly measure in vivo strains during terrestrial walking. Strain analyses verified axial compression and bending as well as high torsion in turtle femora, with peak axial strains comparable to those of other non-avian reptiles at similar walking speeds but higher peak shear strains approaching 2000 μϵ. Planar strain analyses showed patterns of neutral axis (NA)of femoral bending orientations and shifting generally consistent with our previous force-platform analyses of bone stresses, tending to place the anterior and dorsal aspects of the femur in tension and verifying an unexpected pattern from our force studies that differs from patterns in other non-avian reptiles. Calculated femoral safety factors were 3.8 in torsion and ranged from 4.4 to 6.9 in bending. Although these safety factors in bending were lower than values derived from our stress-based calculations, they are similar to strain-based safety factors calculated for other non-avian reptiles in terrestrial locomotion and are still high compared with safety factors calculated for limb bones of birds and mammals. These findings are consistent with conclusions drawn from our previous models of limb bone stresses in turtles and suggest that not only are turtle limb bones `overbuilt' in terms of resisting the loads that they experience during locomotion but also, across tetrapod lineages, elevated torsion and high limb bone safety factors may be primitive features of limb bone design.
Virtual prototyping of flexible soldering cells for electronic manufacture
Authors: Vera D A , Conway P P , Monfared R P , West A A
Published: July 2008

A new generation of soldering facility for small to medium-sized European electronics enterprises has been designed, prototyped, and investigated in a collaborative effort by a number of European manufacturers and research groups. The prototyped soldering cell was designed to improve the agility of small electronics manufacturers to cope with the growing demand for lower-volume batches of highly mixed product varieties.

The proposed flexible soldering cell comprises a number of advanced soldering ovens and a materials handling system. The present paper describes the design specifications and implementation of a three-dimensional virtual engineering environment developed to support system and production engineers during the design, test, and validation phases of various cell control and hardware configurations, by enabling the simulation of a virtual cell‘s response to a range of production scenarios.
Development of multi-axis numerical control program for mill—turn machine
Authors: She Chen-Hua , Hung Chih-Wei
Published: July 2008

A mill—turn machine combining a lathe and machining centre can perform turning and milling operations on the same machine. It can machine a workpiece in one set-up and eliminate errors that can be produced by moving the workpiece between turning and milling machines. Since the mill—turn machine has a complex configuration in which linear and rotary movements are non-orthogonal, generating the part program manually is almost impossible. This work develops an interface called a postprocessor that converts cutter location data generated by a general commercial computer-aided design (CAD)/computer-aided manufacturing (CAM) system into the numerical control (NC) data dedicated for the mill—turn machine. The form-shaping function matrix of the mill—turn machine, which describes the motion trajectory of tool points relative to the workpiece, is derived by the homogeneous coordinate transformation matrix. The complete analytical equations for NC data are obtained through a form-shaping function matrix and inverse kinematics. A window-based postprocessor system written in Borland C++ Builder and OpenGL was developed according to the proposed algorithm. Solid cutting simulation software is utilized to verify the effectiveness of the proposed algorithm.
Modelling and analysis of Airbus wingbox assembly
Authors: Saadat M , Sim R , Najafi F
Published: July 2008

The production of aircraft involves the assembly of large, complex, and deformable components using mechanical fasteners. Assembly problems associated with dimensional variations consistently occur during part-to-part assembly. An investigation of the prediction of the geometric deformation on the next joining location with respect to the present joining location is presented. The direct influence of bolt tightening on the next assembly point is studied using the finite element method (FEM). A case study of the displacement between each foot from the rib of the wingbox with actual data gathered at the Airbus assembly factory is conducted using the FEM and validated on an experimental research test rig. General results obtained from the study indicate that displacement of the next rib foot does occur when assembly of the current rib foot is performed. However, bolt tightening does not significantly contribute to the overall displacement of the rib feet.
Surface integrity and tool life when turning Inconel 718 using ultra-high pressure and flood coolant systems
Authors: Sharman A R C , Hughes J I , Ridgway K
Published: July 2008

The use of high-pressure cutting fluids has been shown to increase tool life or enable higher cutting speeds to be used when machining advanced aerospace materials such as Inconel 718. Cutting fluids act to provide cooling and to reduce friction between the tool and the chip. When supplied at high pressure, greater cooling and penetration of the fluid into the interface between the tool and the chip occur, when compared to conventional flood supply. Both these factors have the potential to alter the resulting surface integrity of the machined component. Following a brief review of the general machinability of Inconel 718, a series of experiments examining the effects of varying the cutting fluid supply pressure and direction of the jet are detailed when finish turning.

Surprisingly, no increase in tool life was observed when using up to 450 bar pressure. When the high-pressure jet was directed at the flank face, reduced flank wear occurred but the level of notching was not affected, resulting in a similar life. Effective chip-breaking occurred at 150 bar; below this, continuous tubular-type chips were produced. Cutting fluid pressure and direction had relatively little influence on the level of surface integrity obtained. However, the use of ultra-high-pressure coolant provided a clear reduction in the level of tensile residual stresses developed in the near-surface layer. The lowest level of residual stress was induced with 450 bar coolant supplied to the flank face. Flood coolant induced a higher tensile stress in the near-surface layer and a larger compressive stress zone beneath this layer.
Quantitative assessment of protection system reliability incorporating human errors
Authors: Etemadi A H , Fotuhi-Firuzabad M
Published: July 2008

The protection system plays a vital role in maintaining a high degree of service reliability in present-day power systems. Considerable work has been done to examine different aspects of protection systems and their associated reliability. All of the reliability predictive methods are based solely on equipment failures, neglecting the human component of the protection system. In this paper, a modified Markov model is presented that incorporates human errors in reliability evaluation of protective devices. Two main types of relay failure (failure to operate and inadvertent operation) are taken into account in the proposed model. The model also considers routine test inspections, the self-checking facility of digital relays, and also common cause failures of protective devices and protected components. Numerical studies show the influence of human errors on protection system reliability.
Generalizing event trees using Bayesian networks
Authors: Marsh D W R , Bearfield G
Published: July 2008

Bayesian networks comprise a probabilistic modelling technique representing influences between uncertain variables. Event trees are a popular technique for modelling the probability of occurrence of accidents in system safety analyses. In this paper it is shown how event trees can be generalized using Bayesian networks. This approach is applied to generalize an existing analysis of train derailment accidents at different track locations on a commuter railway. A number of separate event trees were used in the original analysis; it is shown how these can be replaced with a single generalized model. The generalized derailment model allows new locations to be analysed by selecting the state of the influencing factors appropriate to the location. Moreover, these factors are explicit in the generalized model, whereas the original event trees only included event probabilities that varied by location, with no explicit representation of the causes of these variations. The behaviour of the factors as parameters in an accident model is described, allowing more flexible system-wide risk analysis.
Genetic algorithms for signal grouping in sensor validation: A comparison of the filter and wrapper approaches
Authors: Baraldi P , Zio E , Gola G , Roverso D , Hoffmann M
Published: July 2008

Sensor validation is aimed at detecting anomalies in sensor operation and reconstructing the correct signals of failed sensors, e.g. by exploiting the information coming from other measured signals. In field applications, the number of signals to be monitored can often become too large to be handled by a single validation and reconstruction model. To overcome this problem, the signals can be subdivided into groups according to specific requirements and a number of validation and reconstruction models can be developed to handle the individual groups. In this paper, multi-objective genetic algorithms (MOGAs) are devised for finding groups of signals bearing the required characteristics for constructing signal validation and reconstruction models based on principal component analysis (PCA). Two approaches are considered for the MOGA search of the signal groups: the filter and wrapper approaches. The former assesses the merits of the groups only from the characteristics of their signals, whereas the latter looks for those groups optimal for building the models actually used to validate and reconstruct the signals. The two approaches are compared with respect to a real case study concerning the validation of 84 signals collected from a Swedish boiling water nuclear power plant.
Managing and predicting technological risk and human reliability: A new learning curve theory
Authors: Duffey R B , Saull J W
Published: July 2008

In the use of homotechnological systems (HTSs) over the last two centuries, literally millions and millions of data points have been amassed on human deaths, injuries, losses, damages, disasters, and tragedies. The technological risk needs to be reduced by predicting the human reliability. A fundamental theory based on the learning hypothesis has been developed to provide a sound prediction, which is consistent with the theory of error correction. The rate of reduction of the error rate with increasing experience is proportional to the rate at which errors are occurring. The risk probability for any outcome or error is derived in the form of a ‘human bathtub’ curve. The probability of an outcome as a function of accumulated experience is predicted. The measure of the risk is shown to be the information entropy, which is an objective measure of order observed in organizational learning curves, which arise from the unobserved disorder and statistical fluctuations of human reliability. Thus, the technological risk is inextricably coupled to, and interwoven with, the human reliability by a prediction methodology that is validated by data.
Wear detection of rolling element bearings using multiple-sensing technologies and mixture-model-based clustering method
Authors: Chen S L , Wood R J K , Wang L , Callan R , Powrie H E G
Published: July 2008

Online fault diagnostic technologies are fast emerging for detection of incipient faults on tribological components to avoid catastrophic failure. Vibration analysis has long been used to detect machine faults, but is sensitive to relatively severe conditions only. Electrostatic monitoring is a newly developed approach with the potential to detect precursor processes that indicate contact distress and wear. Recently, at the University of Southampton, both vibration and electrostatic sensors were implemented on a bearing testing rig to evaluate their effectiveness in detecting bearing faults. The results indicate that both types of sensor are sensitive to bearing deterioration shortly before complete failure. However, univariate plots of signals from both types of sensor only exhibit significant change when entering the severe wear stage. Therefore, multivariate techniques for detecting wear severity of components at different running stages need investigating. In this study, an unsupervised training method, called mixture-model-based clustering, that utilizes the expectation maximization (EM) algorithm is employed to develop further a wear detection technique. The choice and extraction of significant features from both vibration and electrostatic sensors are discussed as step one. The second step uses the clustering method to examine the behaviour of the extracted features during different running stages, and to quantify how good the sensors are at distinguishing wear severity. In the third step, a dynamic wear detection process is simulated. Clustering is applied to baseline data from a known healthy bearing and data from different wear stages to see if the data naturally group by wear condition. The result shows that the unsupervised clustering method is able not only to learn and detect wear conditions of the rolling element bearings with the developed statistical monitoring charts of occupation probability (OP) in the clusters and number of the trained clusters (NC), but also to obtain the advantage of detecting insignificant abnormalities that might be overlooked in the conventional plots.
A ternary decision diagram method to calculate the component contributions to the failure of systems undergoing phased missions
Authors: Andrews J D
Published: July 2008

The way that many systems are utilized can be expressed in terms of missions which are split into a sequence of contiguous phases. Mission success is only achieved if each of the phases is successful, and each phase is required to achieve a different objective and use different elements of the system. The reliability analysis of a phased mission system will produce the probability of failure during each of the phases, together with the overall mission failure likelihood. In the event that the system performance does not meet with the acceptance requirement, weaknesses in the design are identified and improvements made to rectify the deficiencies. In conventional system assessments, importance measures can be predicted which provide a numerical indicator of the significance of the role that each component plays in the system failure. Through the development of appropriate importance measures, this paper provides ways of identifying the contribution made by each component failure to each phase failure and the overall mission failure. In addition, a means is given to update the system performance prediction as phases of the mission are successfully completed. The causes of phase failure are expressed as fault trees. The binary decision diagram (BDD) concept is extended to produce ternary decision diagrams (TDDs) to facilitate fast calculation of the importance measures.
Component reliability in fault-diagnosis decision making based on dynamic Bayesian networks
Authors: Weber P , Theilliol D , Aubrun C
Published: July 2008

The decision making in fault diagnosis methods generally relies on the analysis of fault signature vectors. The current paper presents a new approach of decision making for the signature vectors for various identical or similar faults. The main contribution of the paper consists in the fusion between the reliability and the evaluation of the residuals in order to increase the fault isolation efficiency. The decision making, formalized as a Bayesian network, is established with a priori knowledge on fault signatures, false alarm and missing detection probability, online component state estimation computed by a Bayesian fusion of the component reliability, and measurements. The effectiveness and performances of the method are illustrated on a heating water process corrupted by various faults.
Reliable fault diagnosis scheme for a spacecraft attitude control system
Authors: Patton R J , Uppal F J , Simani S , Polle B
Published: July 2008

This paper presents a scheme for fault detection and isolation (FDI) of on-board gyroscope sensors and thrusters for spacecraft attitude control, based on the example of the Mars Express (MEX) satellite. The main contribution of the paper is related to the design and the optimization of an FDI procedure based on robust observers or filters, used as estimators, which generate the FDI residual signals. When organized into an estimator bank, excellent fault isolation properties are achieved upon suitable design. The residual evaluation relies on decision logic, whose thresholds are properly selected and specified. The FDI strategy is applied to the non-linear simulation of the MEX system, and the FDI performance is evaluated subject to disturbance signals, model uncertainty, and measurement noise processes. The robustness and reliability properties of the robust residual generators are investigated and verified in simulation by selecting suitable performance criteria together with Monte Carlo analysis. The results obtained highlight a good trade-off between solution complexity and achieved performances. Comparisons with the existing fault diagnosis algorithms implemented on board the MEX spacecraft are finally reported. The proposed FDI design methodology constitutes a reliability approach for real application of FDI in future spacecraft.
Efficient Hydrogenation of Ethyl Lactate to 1,2-Propanediol over Ru–B/TiO2 in Aqueous Solution
Authors: Fan Guang-Yin , Zhang Ye , Zhou Ya-Fen , Li Rui-Xiang , Chen Hua , Li Xian-Jun
Published: July 2008

Catalyst Ru–B/TiO2 showed an excellently catalytic performance for the hydrogenation of ethyl lactate to 1,2-propanediol (1,2-PDO) under mild conditions (90 °C and 4.0 MPa H2) without any additive. Especially, the activity of the catalyst was greatly improved in aqueous solution. The conversion of ethyl lactate was up to 98% and the selectivity to 1,2-propanediol was over 95%.
One-pot Preparation of Core–Shell Structure Titania/Polyaniline Hybrid Materials: The Effect of Sodium Dodecyl Sulfate Surfactant
Authors: Han Youn-Gyu , Kusunose Takafumi , Sekino Tohru
Published: July 2008

Polyaniline (PANI)-coated titania (TiO2) have been prepared with ammonium persulfate (APS) as an oxidant in aqueous sodium dodecyl sulfate (SDS) micellar solution. The addition of a small amount of TiO2 nanoparticles greatly increased electrical conductivity from 5.89 to 14.2 S/cm. The effect of SDS for TiO2@PANI composites was studied in terms of morphology of the core–shell structure, dispersibility of TiO2 in composites, and electrical conductivity.
Preparation, Structure, and Spectral Properties of Cyclophanes Consisting of Oligothiophene Units
Authors: Tsuge Akihiko , Hara Takeshi , Moriguchi Tetsuji , Yamaji Minoru
Published: July 2008

Small-sized cyclophanes consisting of oligothiophene units as a component have been prepared. Correlation between the cyclophane structure and fluorescence spectral properties has been examined. It has been found that emission from intramolecular excimer-formation is confirmed for the cyclophanes having two or three thiophene units, but not for those having four or five thiophene units with the β-hexyl chain.
Synthesis of Oligosaccharides of Genistein and Quercetin as Potential Anti-inflammatory Agents
Authors: Shimoda Kei , Kobayashi Tatsunari , Akagi Masaaki , Hamada Hatsuyuki , Hamada Hiroki
Published: July 2008

Genistein was glucosylated to its 7-O-β-d-glucoside by cultured cells of Ipomoea batatas, while cultured Marchantia polymorpha cells produced 4′-O-β-d-glucoside and 7-O-β-d-glucoside of genistein. On the other hand, quercetin was converted into its 3-O-β-d-glucoside by I. batatas, and M. polymorpha gave 3-O-β-d-glucoside and 7-O-β-d-glucoside of quercetin. These four glucosides were further glycosylated to the corresponding β-maltosides and β-maltotriosides by cyclodextrin glucanotransferase. Genistein 7-O-β-maltooligosaccharides, quercetin 3-O-β-glucoside, and quercetin 7-O-β-maltooligosaccharides showed potent inhibitory effects on histamine release from rat peritoneal mast cells.
Why Does near Infrared Transmittance Spectroscopy Discriminate Quark-Type Cheese Manufactured in the Presence or Absence of Aflatoxin M1 (AFM1)?
Authors: Cattaneo Tiziana Maria Piera , Cabassi Giovanni , Panarelli Elena Veronica , Giangiacomo Roberto
Published: July 2008

Many studies on milk have demonstrated that aflatoxin M1 (AFM1) binds to milk proteins and, in particular, to casein and that it was concentrated in the curd during the manufacture of cheese. Investigations on the affinity of AFM1 towards different proteins in milk are very limited, even if this aspect appears to be particularly important due to its influence in quantitative toxin recovery in cheese. The aim of this work was a better comprehension of why near infrared (NIR) transmittance spectral analysis in the range 850 – 1050 nm, could discriminate Quark type cheese manufactured using milk at different levels of AFM1 contamination (control < 50 ppt 100 ppt ppt and 200 ppt). Cheese-making was carried out at the experimental pilot plant of the Dairy Science Institute in Lodi under strictly controlled conditions. Each cheese production was repeated twice (six tests, 20 L each). Cheese samples were analysed for fat, protein, dry matter and AFM1 content at time 0 and during storage for 19 days (every three days) for a total of 42 samples. Capillary electrophoresis (CE) profiles and (NIR) transmittance spectra, were also collected. Spectra, corrected for scattering, were processed by multivariate curve resolution classical least squares using the estimation of individual constituents (fat, protein, water) for signal interpretation in the investigated region. Partial least squares regression (PLSR) results showed a good NIR transmittance discrimination power between contaminated and uncontaminated samples. Comparable results were obtained by applying PLSR to CE data using the peak area of αs1-I-casein as the variable. The regressors obtained by the two PLSR were very similar, with the highest significance at 950 nm. This work demonstrated that the indirect spectroscopic detection of AFM1 is strongly related to the cheese proteolytic trend.
At-Line Monitoring of the Leavening Process in Industrial Bread Making by near Infrared Spectroscopy
Authors: Ulrici Alessandro , Vigni Mario Li , Durante Caterina , Foca Giorgia , Belloni Paolo , Brettagna Barbara , De Marco Tommaso , Cocchi Marina
Published: July 2008

The potential of near infrared (NIR) spectroscopy to characterise doughs for industrial bread making, directly at the production plant, was investigated. Different stages of dough processing have been monitored at-line, employing a Fourier transform-NIR instrument equipped with an optical fibre. Parallel factors analysis has been used to study the spectral variation throughout the production line, with the aim of acquiring indications on the modifications the dough undergoes during the process. Moreover, wavelet interface for linear modelling analysis, which performs variable selection in the wavelet domain, has been employed to explore the possibility of monitoring the leavening step by identifying a relationship between the NIR signal and the leavening phase, considering the leavening time and the total titrable acidity of the dough. Results show that some aspects of the leavening process can be calibrated from the NIR spectra, thus corroborating the fact that the NIR signal is influenced by the modifications that occur along with the production process
Particle Size Optimisation in Development of near Infrared Microscopy Methodology to Build Spectral Libraries of Animal Feeds
Authors: del Valle Fernández-Ibáñez Maria , Soldado Ana , Vicente Fernando , Martínez-Fernández Adela , de la Roza-Delgado Begoña
Published: July 2008

Near infrared spectroscopy coupled to a microscope (NIRM) is a technique where the infrared beam is focused on each particle (< 50 μm) of a sample to collect NIR spectra. In this work, the experimental conditions (sample pre-treatment and instrumental) have been evaluated and compared for collecting spectral information in order to develop a strategy able to build large and robust spectral libraries to be transferred between NIRM instruments. To attempt this objective, we selected the most representative ingredients included in animal feeds: straw as low density forage, soybean as raw material and total mixed ration (TMR). Then, different mills, sieves and the number of spectra to be averaged were evaluated, selecting those that minimise noise and scanning time. The best results were obtained grinding through 1 mm sieve ingredients and TMR and collecting each particle spectra by scanning 70 individual spectra averaged as pre-treatment and instrumental conditions to obtain the most relevant information about each ingredient.