bluuebunny/crossref_metadata_2025 huggingface dataset:
Genome-wide analysis of condensin binding in Caenorhabditis elegans
Authors: Kranz Anna-Lena , Jiao Chen-Yu , Winterkorn Lara Heermans , Albritton Sarah Elizabeth , Kramer Maxwell , Ercan Sevinç
Published: October 2013

Background

Condensins are multi-subunit protein complexes that are essential for chromosome condensation during mitosis and meiosis, and play key roles in transcription regulation during interphase. Metazoans contain two condensins, I and II, which perform different functions and localize to different chromosomal regions. Caenorhabditis elegans contains a third condensin, IDC, that is targeted to and represses transcription of the X chromosome for dosage compensation.

Results

To understand condensin binding and function, we performed ChIP-seq analysis of C. elegans condensins in mixed developmental stage embryos, which contain predominantly interphase nuclei. Condensins bind to a subset of active promoters, tRNA genes and putative enhancers. Expression analysis in kle-2-mutant larvae suggests that the primary effect of condensin II on transcription is repression. A DNA sequence motif, GCGC, is enriched at condensin II binding sites. A sequence extension of this core motif, AGGG, creates the condensin IDC motif. In addition to differences in recruitment that result in X-enrichment of condensin IDC and condensin II binding to all chromosomes, we provide evidence for a shared recruitment mechanism, as condensin IDC recruiter SDC-2 also recruits condensin II to the condensin IDC recruitment sites on the X. In addition, we found that condensin sites overlap extensively with the cohesin loader SCC-2, and that SDC-2 also recruits SCC-2 to the condensin IDC recruitment sites.

Conclusions

Our results provide the first genome-wide view of metazoan condensin II binding in interphase, define putative recruitment motifs, and illustrate shared loading mechanisms for condensin IDC and condensin II.
Time-lapse seismic signal analysis for enhanced oil recovery at Cranfield CO2 sequestration site, Cranfield field, Mississippi
Authors: Ditkof Julie , Caspari Eva , Pevzner Roman , Urosevic Milovan , Meckel Timothy A. , Hovorka Susan D.
Published: October 2013

The Cranfield field in southwest Mississippi has been under continuous [Formula: see text] injection by Denbury Onshore LLC since 2008. Two 3D seismic surveys were collected in 2007 and 2010. An initial 4D seismic response was characterized after three years of injection, where more than three million tons of [Formula: see text] remain in the subsurface. This interpretation showed coherent seismic amplitude anomalies in some areas that received large amounts of [Formula: see text] but not in others. To understand these effects better, we performed Gassmann substitution modeling at two wells: the 31F-2 observation well and the 28-1 injection well. We aimed to predict a postinjection saturation curve and acoustic impedance (AI) change through the reservoir. Seismic volumes were cross-equalized, well ties to seismic were performed, and AI inversions were subsequently carried out. Inversion results showed that the change in AI is higher than Gassmann substitution predicted for the 28-1 injection well. The time-lapse AI difference predicted by the inversion is similar in magnitude to the difference inferred from a time delay along a marker horizon below the reservoir.
Interpretation of full-azimuth broadband land data from Saudi Arabia and implications for improved inversion, reservoir characterization, and exploration
Authors: Wallick Brian P. , Giroldi Luis
Published: October 2013

Interpretation of conventional land seismic data over a Permian-age gas field in Eastern Saudi Arabia has proven difficult over time due to low signal-to-noise ratio and limited bandwidth in the seismic volume. In an effort to improve the signal and broaden the bandwidth, newly acquired seismic data over this field have employed point receiver technology, dense wavefield sampling, a full azimuth geometry, and a specially designed sweep with useful frequencies as low as three hertz. The resulting data display enhanced reflection continuity and improved resolution. With the extension of low frequencies and improved interpretability, acoustic impedance inversion results are more robust and allow greater flexibility in reservoir characterization and prediction. In addition, because inversion to acoustic impedance is no longer completely tied to a wells-only low-frequency model, there are positive implications for exploration.
Justifying the Proof Structure of Criminal Trials
Authors: Lippke Richard L.
Published: October 2013

During criminal trials, defendants enjoy a presumption of innocence, the burden of proof is on the government, and the standard of proof it must meet—beyond a reasonable doubt—is exacting. This ‘proof structure’ of trials is usually justified with an error distribution rationale. Yet there are well-known difficulties in establishing the optimal ratio of errors of false conviction to errors of false acquittals and with determining whether the proof structure enables us to obtain that ratio over a sufficiently lengthy run of cases. According to an alternative justification of the proof structure, individuals have a second-order moral right to demand rigorous, independent evaluations of the evidence that they have committed crimes before their primary moral rights are curtailed by legal punishment. The proof structure of criminal trials is one way to honour this right. Various objections to this defence of the proof structure are considered.
Coating processes for plastic optics
Authors: Schulz Ulrike
Published: October 2013

Transparent plastics have been used for optical applications with growing demand. This development is accompanied by a desire for extended surface functionalities. Most important optical surface function is antireflection (AR), which is performed mainly by applying plasma-assisted processes. Critical considerations for coating polymers include interaction with emission from plasma and thermal stress. State-of-the-art vacuum processes for coating on plastic, as well as new results of research and development in the fields of AR design and AR structures will be introduced and discussed.
Folding of peptides and proteins: role of disulfide bonds, recent developments
Authors: Hidaka Yuji , Shimamoto Shigeru
Published: October 2013

Disulfide-containing proteins are ideal models for studies of protein folding as the folding intermediates can be observed, trapped, and separated by HPLC during the folding reaction. However, regulating or analyzing the structures of folding intermediates of peptides and proteins continues to be a difficult problem. Recently, the development of several techniques in peptide chemistry and biotechnology has resulted in the availability of some powerful tools for studying protein folding in the context of the structural analysis of native, mutant proteins, and folding intermediates. In this review, recent developments in the field of disulfide-coupled peptide and protein folding are discussed, from the viewpoint of chemical and biotechnological methods, such as analytical methods for the detection of disulfide pairings, chemical methods for disulfide bond formation between the defined Cys residues, and applications of diselenide bonds for the regulation of disulfide-coupled peptide and protein folding.
Septin 9 amplification and isoform-specific expression in peritumoral and tumor breast tissue
Authors: Connolly Diana , Hoang Hien G. , Adler Esther , Tazearslan Cagdas , Simmons Nichelle , Bernard Vahni Vishala , Castaldi Maria , Oktay Maja H. , Montagna Cristina
Published: October 2013

Septins are a large family of GTP-binding proteins abnormally expressed in many solid tumors. Septin 9 (SEPT9) in particular has been found overexpressed in diverse human tumors including breast, head and neck, ovarian, endometrial, kidney, and pancreatic cancer. Although we previously reported SEPT9 amplification in breast cancer, we now show specifically that high-grade breast carcinomas, the subtype with worst clinical outcome, exhibit a significant increase in SEPT9 copy number when compared with other tumor grades. We also present, for the first time, a sensitive and quantitative measure of seven (SEPT9_v1 through SEPT9_v7) isoform variant mRNA levels in mammary epithelial cells. SEPT9_v1, SEPT9_v3, SEPT9_v6, and SEPT9_v7 isoforms were expressed at the highest levels followed by SEPT9_v2 and SEPT9_v5, whereas SEPT9_v4 was almost undetectable. Although most of the isoforms were upregulated in primary tumor tissues relative to the patient-matched peritumoral tissues, SEPT9_v4 remained the lowest expressing isoform. This comprehensive analysis of SEPT9 provides substantial evidence for increased SEPT9 expression as a consequence of genomic amplification and is the first study to profile SEPT9_v1 through SEPT9_v7 isoform-specific mRNA expression in tumor and nontumor tissues from patients with breast cancer.
Exact Nonparametric Confidence Bands for the Survivor Function
Authors: Matthews David
Published: October 2013

A method to produce exact simultaneous confidence bands for the empirical cumulative distribution function that was first described by Owen, and subsequently corrected by Jager and Wellner, is the starting point for deriving exact nonparametric confidence bands for the survivor function of any positive random variable. We invert a nonparametric likelihood test of uniformity, constructed from the Kaplan–Meier estimator of the survivor function, to obtain simultaneous lower and upper bands for the function of interest with specified global confidence level. The method involves calculating a null distribution and associated critical value for each observed sample configuration. However, Noe recursions and the Van Wijngaarden–Decker–Brent root-finding algorithm provide the necessary tools for efficient computation of these exact bounds. Various aspects of the effect of right censoring on these exact bands are investigated, using as illustrations two observational studies of survival experience among non-Hodgkin’s lymphoma patients and a much larger group of subjects with advanced lung cancer enrolled in trials within the North Central Cancer Treatment Group. Monte Carlo simulations confirm the merits of the proposed method of deriving simultaneous interval estimates of the survivor function across the entire range of the observed sample.

This research was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada. It was begun while the author was visiting the Department of Statistics, University of Auckland, and completed during a subsequent sojourn at the Medical Research Council Biostatistics Unit in Cambridge. The support of both institutions, in addition to that of NSERC and the University of Waterloo, is greatly appreciated.
Evaluation of in vitro aldose reductase inhibitory potential of alkaloidal fractions of Piper nigrum, Murraya koenigii, Argemone mexicana, and Nelumbo nucifera
Authors: Gupta Sakshi , Singh Nirmal , Jaggi Amteshwar Singh
Published: October 2013

Background: Aldose reductase is primarily involved in development of long-term diabetic complications due to increased polyol pathway activity. The synthetic aldose reductase inhibitors are not very successful clinically. Therefore, the natural sources may be exploited for safer and effective aldose reductase inhibitors.

Methods: In the present study, the aldose reductase inhibitory potential of hydroalcoholic and alkaloidal extracts of Piper nigrum, Murraya koenigii, Argemone mexicana, and Nelumbo nucifera was evaluated. The hydroalcoholic and alkaloidal extracts of the selected plants were prepared. The different concentrations of hydroalcoholic and alkaloidal extracts of these plants were evaluated for their goat lens aldose reductase inhibitory activity using dl-glyceraldehyde as substrate. The aldose reductase inhibitory potential of extracts was assessed in terms of their IC50 value.

Results: Amongst the hydroalcoholic extracts, the highest aldose reductase inhibitory activity was shown by P. nigrum (IC50 value 35.64±2.7 μg/mL) followed by M. koenigii (IC50 value 45.67±2.57 μg/mL), A. mexicana (IC50 value 56.66±1.30 μg/mL), and N. nucifera (IC50 value 59.78±1.32 μg/mL). Among the alkaloidal extracts, highest inhibitory activity was shown by A. mexicana (IC50 value 25.67±1.25 μg/mL), followed by N. nucifera (IC50 value 28.82±1.85 μg/mL), P. nigrum (IC50 value 30.21±1.63 μg/mL), and M. koenigii (IC50 value 35.66±1.64 μg/mL).

Conclusions: It may be concluded that the alkaloidal extracts of these plants possess potent aldose reductase inhibitory activity and may be therapeutically exploited in diabetes-related complications associated with increased activity of aldose reductase.
Methylglyoxal causes endothelial dysfunction: the role of endothelial nitric oxide synthase and AMP-activated protein kinase α
Authors: Turkseven Saadet , Ertuna Elif , Yetik-Anacak Gunay , Yasa Mukadder
Published: October 2013

Background: Methylglyoxal is a major precursor in the formation of advanced glycation end products and is associated with the pathogenesis of diabetes-related vascular complications. The aim of this study was to evaluate whether methylglyoxal induces endothelial dysfunction and to determine the contributors involved in this process.

Methods: Rat thoracic aortic rings were treated for 24 h with 100 μM methylglyoxal by using an organ culture method. A cumulative dose-response curve to acetylcholine was obtained to determine endothelium-dependent relaxation. The protein levels of endothelial nitric oxide synthase (eNOS) and its phosphorylated form at the serine 1177 site [p-eNOS (Ser1177)], heat shock protein 90 (Hsp90), AMP-activated protein kinase α (AMPKα) and its phosphorylated form at the threonine 172 site [p-AMPKα (Thr172)] were evaluated. Superoxide production was determined by lucigenin-chemiluminescence.

Results: Treatment with 100 μM methylglyoxal for 24 h decreased acetylcholine-induced vascular relaxation. The levels of eNOS and p-eNOS (Ser1177) were reduced while no effect on Hsp90 was observed. Levels of p-AMPKα (Thr172) were significantly decreased without any change in total AMPKα protein levels. Superoxide level was not affected by methylglyoxal treatment.

Conclusions: In rat aortic rings, methylglyoxal determines a reduction in endothelium-dependent relaxation. This effect seems to be mediated via a reduction in p-eNOS (Ser1177) and p-AMPKα (Thr172).
Multicore fibers for large capacity transmission
Authors: Saitoh Kunimasa , Matsuo Shoichiro
Published: October 2013

We experience Internet traffic growth of 100 times every 10 years. However, the capacity of existing standard single-mode fiber is approaching its fundamental limit regardless of significant realization of transmission technologies which allow for high spectral efficiencies. Space division multiplexing (SDM) based on multicore fibers (MCFs) has emerged as a solution to the problem of saturation of the capacity of optical transmission systems. This article presents the recent progress on the MCFs for future large capacity long-distance transmission systems. In MCFs, there is a tradeoff relationship between low crosstalk and high multiplicity, therefore the maximum number of cores and the core arrangement have to be carefully determined based on the required crosstalk level and core size. The state-of-the-art of fabricated MCFs and the transmission experiments using MCFs are reviewed. The current maximum capacity-distance product in MCF transmission is 368.2 (184.1+184.1) Pb/s/fiber km with the relative spatial efficiency of 4.7 compared with a standard single-mode fiber. In order to increase the spatial efficiency as well as the capacity-distance product further in MCFs, the possibility of heterogeneous MCFs and few-mode MCFs is also presented.
Linkage Relationships Among Multiple QTL for Horticultural Traits and Late Blight (P. infestans) Resistance on Chromosome 5 Introgressed from Wild TomatoSolanum habrochaites
Authors: Haggard J Erron , Johnson Emily B , St. Clair Dina A
Published: October 2013

When the allele of a wild species at a quantitative trait locus (QTL) conferring a desirable trait is introduced into cultivated species, undesirable effects on other traits may occur. These negative phenotypic effects may result from the presence of wild alleles at other closely linked loci that are transferred along with the desired QTL allele (i.e., linkage drag) and/or from pleiotropic effects of the desired allele. Previously, a QTL for resistance to Phytophthora infestans on chromosome 5 of Solanum habrochaites was mapped and introgressed into cultivated tomato (S. lycopersicum). Near-isogenic lines (NILs) were generated and used for fine-mapping of this resistance QTL, which revealed coincident or linked QTL with undesirable effects on yield, maturity, fruit size, and plant architecture traits. Subsequent higher-resolution mapping with chromosome 5 sub-NILs revealed the presence of multiple P. infestans resistance QTL within this 12.3 cM region. In our present study, these sub-NILs were also evaluated for 17 horticultural traits, including yield, maturity, fruit size and shape, fruit quality, and plant architecture traits in replicated field experiments over the course of two years. Each previously detected single horticultural trait QTL fractionated into two or more QTL. A total of 41 QTL were detected across all traits, with ∼30% exhibiting significant QTL × environment interactions. Colocation of QTL for multiple traits suggests either pleiotropy or tightly linked genes control these traits. The complex genetic architecture of horticultural and P. infestans resistance trait QTL within this S. habrochaites region of chromosome 5 presents challenges and opportunities for breeding efforts in cultivated tomato.
Rapid Degeneration of Noncoding DNA Regions SurroundingSlAP3X/YAfter Recombination Suppression in the Dioecious PlantSilene latifolia
Authors: Ishii Kotaro , Nishiyama Rie , Shibata Fukashi , Kazama Yusuke , Abe Tomoko , Kawano Shigeyuki
Published: October 2013

Silene latifolia is a dioecious plant with heteromorphic XY sex chromosomes. Previous studies of sex chromosome–linked genes have suggested a gradual divergence between the X-linked and the Y-linked genes in proportion to the distance from the pseudoautosomal region. However, such a comparison has yet to be made for the noncoding regions. To better characterize the nonrecombining region of the X and Y chromosomes, we sequenced bacterial artificial chromosome clones containing the sex chromosome–linked paralogs SlAP3X and SlAP3Y, including 115 kb and 73 kb of sequences, respectively, flanking these genes. The synonymous nucleotide divergence between SlAP3X and SlAP3Y indicated that recombination stopped approximately 3.4 million years ago. Sequence homology analysis revealed the presence of six long terminal repeat retrotransposon-like elements. Using the nucleotide divergence calculated between left and right long terminal repeat sequences, insertion dates were estimated to be 0.083–1.6 million years ago, implying that all elements detected were inserted after recombination stopped. A reciprocal sequence homology search facilitated the identification of four homologous noncoding DNA regions between the X and Y chromosomes, spanning 6.7% and 10.6% of the X chromosome–derived and Y chromosome–derived sequences, respectively, investigated. Genomic Southern blotting and fluorescence in situ hybridization showed that the noncoding DNA flanking SlAP3X/Y has homology to many regions throughout the genome, regardless of whether they were homologous between the X and Y chromosomes. This finding suggests that most noncoding DNA regions rapidly lose their counterparts because of the introduction of transposable elements and indels (insertion–deletions) after recombination has stopped.
Treatment outcome of primary testicular non-Hodgkin’s lymphoma
Authors: Iványi János László , Marton Éva , Plander Márk , Engert Zoltán Vendel , Tóth Csaba
Published: October 2013

Introduction: Primary testicular lymphoma constitutes a rare subgroup among extranodal non-Hodgkin’s lymphomas. Because of its aggressive clinical behaviour due to high grade histological features developing mainly in older population, patients with this disease usually have a poor prognosis. Orchidectomy followed by combination immunochemotherapy is a traditional treatment method with a rather inferior outcome. Aim: In this retrospective survey the authors analysed the clinical presentation, pathological features and treatment results of patients with primary testicular lymphoma diagnosed and treated in their haematology centre between 2000–2012 Method: During this period 334 patients with aggressive non-Hodgkin’s lymphomas were treated, of whom 8 patients (2.39%; age between 23 and 86 years; median, 60 years) underwent semicastration for primary testicular lymphoma (7 patients had diffuse, large B-cell lymphoma and one patient had Burkitt-like lymphoma). According to the Ann Arbor staging system a limited stage I-IIE was diagnosed in 7 patients and advanced stage was found in one patient. All but one patients were treated with rituximab added to CHOP regimen (6 or 8 cycles in every 21 or 28 days), whereas one patient received radiotherapy only. Central nervous system intrathecal prophylaxis was used in one case and no preventive irradiation of the contralateral testis was used. Results: With a median follow-up of 50 months complete remission was observed in 7 patients. However, two patients died (one due to progression and one in remission from pulmonary solid tumour). Complete remission rate proved to be 87.5%, disease-free survival was between 13 and 152 months (median 38 months) and overall survival rates were between 17 and 156 months (median 43 months). The 5-year disease-free and overall survival rates were 37.5 %. Conclusions: The relatively favourable treatment outcome could be mainly explained by the high number of patients with early-stage of the disease, early surgical removal of testicular lymphomas and the use if immunochemotherapy. This therapeutic regimen was effective to prevent localized and distant relapses. Despite omission of regular prophylaxis of the central nervous system, no relapse was detected. Orv. Hetil., 154 (42), 1666–1673.
Video-Assisted Palatopharyngeal Surgery: A Model for Improved Education and Training
Authors: Allori Alexander C. , Marcus Jeffrey R. , Daluvoy Sanjay , Bond Jennifer
Published: October 2013

Objective

The learning process for intraoral procedures is arguably more difficult than for other surgical procedures because of the assistant's severely limited visibility. Consequently, trainees may not be able to adequately see and follow all steps of the procedure, and attending surgeons may be less willing to entrust trainees with critical portions of the procedure. In this report, we propose a video-assisted approach to intraoral procedures that improves lighting, visibility, and potential for effective education and training.

Design

Technical report (idea/innovation).

Setting

Tertiary referral hospital.

Patients

Children with cleft palate and velopharyngeal insufficiency requiring surgery.

Interventions

Video-assisted palatoplasty, sphincteroplasty, and pharyngoplasty.

Main Outcome Measures

Qualitative and semiquantitative educational outcomes, including learner perception regarding “real-time” (video-assisted surgery) and “non–real-time” (video-library–based) surgical education.

Results

Trainees were strongly in favor of the video-assisted modality in “real-time” surgical training. Senior trainees identified more opportunities in which they had been safely entrusted to perform critical portions of the procedure, corresponding with satisfaction with the learning process scores, and they showed greater comfort/confidence scores related to performing the procedure under supervision and alone.

Conclusions

Adoption of the video-assisted approach can be expected to markedly improve the learning curve for surgeons in training. This is now standard practice at our institution. We are presently conducting a full educational technology assessment to better characterize the effect on knowledge acquisition and technical improvement.
When is a parasite not a parasite? Effects of larval tick burdens on white‐footed mouse survival
Authors: Hersh Michelle H. , LaDeau Shannon L. , Previtali M. Andrea , Ostfeld Richard S.
Published: October 2013

Many animal species can carry considerable burdens of ectoparasites: parasites living on the outside of a host's body. Ectoparasite infestation can decrease host survival, but the magnitude and even direction of survival effects can vary depending on the type of ectoparasite and the nature and duration of the association. When ectoparasites also serve as vectors of pathogens, the effects of ectoparasite infestation on host survival have the potential to alter disease dynamics by regulating host populations and stabilizing transmission. We quantified the impact of larval Ixodes scapularis tick burdens on both within‐season and overwinter survival of white‐footed mice (Peromyscus leucopus) using a hierarchical Bayesian capture‐mark‐recapture model. I. scapularis and P. leucopus are, respectively, vectors and competent reservoirs for the causative agents of Lyme disease, anaplasmosis, and babesiosis. Using a data set of 5587 individual mouse capture histories over sixteen years, we found little evidence for any effect of tick burdens on either within‐season or overwinter mouse survival probabilities. In male mice, tick burdens were positively correlated with within‐season survival probabilities. Mean maximum tick burdens were also positively correlated with population rates of change during the concurrent breeding season. The apparent indifference of mice to high tick burdens may contribute to their effectiveness as reservoir hosts for several human zoonotic pathogens.
The Pathophysiology of Primary Hip Osteoarthritis may Originate from Bone Alterations
Authors: Kamimura Mikio , Nakamura Yukio , Ikegami Shota , Mukaiyama Keijiro , Uchiyama Shigeharu , Kato Hiroyuki
Published: October 2013

Objectives:

The aim of this study was to investigate whether bone alterations detected by hip magnetic resonance imaging (MRI) were associated with subsequent primary hip OA.

Methods:

We enrolled 7 patients with hip joint pain from their first visit, at which hip joints were classified as grade 0 or I on the Kellgren-Lawrence grading scale. Plain radiographs and magnetic resonance imaging (MRI) were performed on all cases, and pain was assessed with the Denis pain scale. Average age, height, weight, body mass index, bone mineral density (L1-4), central edge angle, Sharp’s angle, and acetabular hip index were calculated.

Results:

Within two months of the onset of pain, 4 of the 7 cases showed broad bone signal changes, while 3 cases showed local signal changes in the proximal femur on hip MRI. Three to 6 months after the onset of pain, in all patients whose pain was much improved, plain radiographs showed progression to further-stage OA.

Conclusion:

Our findings suggest that bone abnormalities in the proximal femur might be involved in the pathogenesis of primary hip OA.
Tourism climatic index in the valorisation of climate in tourist centers of Montenegro
Authors: Joksimovic Marko , Gajic Mirjana , Golic Rajko
Published: October 2013

Climate is one of the main factors for the development of recreational forms
of tourism in Montenegro. It affects the temporal arrangement and spatial
distribution of tourists throughout the year. It determines the context of
the environment in which the activities of tourists take place and represents
the tourism resources. It is important for the planning and construction of
tourism facilities and infrastructure, as well as the organization of tourism
activities. This paper presents the tourism climatic index as a bioclimatic
indicator for determining the conditions suitable for recreational tourism
throughout the year. Research results according to the case study indicate
the comparative advantages and also the lack of climate as the resource in
tourism of Montenegro. There is an apparent underutilization of periods with
climate conditions that work in favour of recreational forms of tourism. The
uneven spatial and temporal arrangement of suitable climatic conditions in
the tourist centres is the factor of the formation of seasonality of tourism
trends. However, the results of linear correlation of tourism climatic index
and monthly visits point to the incompatibility of potentials with capacity
utilization.
Natural radioactivity in imported ceramic tiles used in Serbia
Authors: Jankovic Marija , Rajacic Milica , Rakic Tamara , Todorovic Dragana
Published: October 2013

Ceramic tiles are one of the commonly used decorative building materials.
Body of ceramic tiles is a mixture of different raw materials including
clays, quartz materials and feldspat, and may be glazed or left unglazed. Due
to the presence of zircon in the glaze, ceramic tiles can show natural
radioactivity concentration significantly higher than the average values for
building materials. This study presents a summary of results obtained by a
survey which was consisted of measurements of activity concentrations of
natural radionuclides in imported ceramic tile samples used in Serbia using a
gamma spectrometer with HPGe detector. Based on the obtained concentrations,
gamma index, radium equivalent activity, the indoor absorbed dose rate and
the corresponding annual effective dose were evaluated to assess the
potential radiological hazard associated with these building materials.
Incremental Filling Technique and Composite Material—Part II: Shrinkage and Shrinkage Stresses
Authors: Bicalho AA , Valdívia ADCM , Barreto BCF , Tantbirojn D , Versluis A , Soares CJ
Published: October 2013

Objectives

Finite element analysis (FEA) was used to study polymerization shrinkage stress in molars restored with composites and to correlate those stresses with experimentally measured tooth deformation.

Methods

Three composites (Filtek LS, Aelite LS Posterior, Filtek Supreme) and three filling techniques (bulk, 2.0-mm increments, and 1.0-mm increments) for restoring a molar were simulated in a two-dimensional FEA. Polymerization shrinkage was modeled using post-gel shrinkage, which was measured using the strain gauge technique (n=10). Cuspal tooth deformation, measured at the buccal and lingual surfaces with strain gauges in a laboratory study, was used to validate the analysis. Residual shrinkage stresses were expressed in modified von Mises equivalent stresses. Linear Pearson correlations were determined between the laboratory and FEA results.

Results

Post-gel shrinkage values (in volume %) were: Filtek LS (0.11 ± 0.03) < Aelite LS Posterior (0.51 ± 0.02) < Filtek Supreme (0.62 ± 0.09). The 1.0-mm increment filling caused substantially higher stresses and strains in the cervical enamel region. Significant correlations were found between: elastic modulus and FEA strain, elastic modulus and FEA stress, post-gel shrinkage and FEA strain, post-gel shrinkage and FEA stress, FEA strain and cuspal deformation by strain gauge, and FEA stress and cuspal deformation by strain gauge (p<0.05).

Conclusions

Increasing the number of increments and high post-gel shrinkage and/or elastic modulus values caused higher stresses in the remaining tooth structure and tooth/restoration interface. Cuspal deformation measured with the strain gauge method validated the finite element analyses.
Bifurcation and control for a discrete-time prey–predator model with Holling-IV functional response
Authors: Chen Qiaoling , Teng Zhidong , Hu Zengyun
Published: October 2013

The dynamics of a discrete-time predator-prey model with Holling-IV functional response are investigated. It is shown that the model undergoes a flip bifurcation, a Hopf bifurcation and a saddle-node bifurcation by using the center manifold theorem and bifurcation theory. Numerical simulations not only exhibit our results with the theoretical analysis, but also show the complex dynamical behaviors, such as the period-3, 6, 9, 12, 20, 63, 70, 112 orbits, a cascade of period-doubling bifurcations in period-2, 4, 8, 16, quasi-periodic orbits, an attracting invariant circle, an inverse period-doubling bifurcation from the period-32 orbit leading to chaos and a boundary crisis, a sudden onset of chaos and a sudden disappearance of the chaotic dynamics, attracting chaotic sets and non-attracting sets. We also observe that when the prey is in chaotic dynamics the predator can tend to extinction or to a stable equilibrium. Specifically, we stabilize the chaotic orbits at an unstable fixed point by using OGY chaotic control.
An analytical and numerical approach to a bilateral contact problem with nonmonotone friction
Authors: Barboteu Mikaël , Bartosz Krzysztof , Kalita Piotr
Published: October 2013

We consider a mathematical model which describes the contact between a linearly elastic body and an obstacle, the so-called foundation. The process is static and the contact is bilateral, i.e., there is no loss of contact. The friction is modeled with a nonmotonone law. The purpose of this work is to provide an error estimate for the Galerkin method as well as to present and compare two numerical methods for solving the resulting nonsmooth and nonconvex frictional contact problem. The first approach is based on the nonconvex proximal bundle method, whereas the second one deals with the approximation of a nonconvex problem by a sequence of nonsmooth convex programming problems. Some numerical experiments are realized to compare the two numerical approaches.
A general transfer function representation for a class of hyperbolic distributed parameter systems
Authors: Bartecki Krzysztof
Published: October 2013

Results of transfer function analysis for a class of distributed parameter systems described by dissipative hyperbolic partial differential equations defined on a one-dimensional spatial domain are presented. For the case of two boundary inputs, the closed-form expressions for the individual elements of the 2×2 transfer function matrix are derived both in the exponential and in the hyperbolic form, based on the decoupled canonical representation of the system. Some important properties of the transfer functions considered are pointed out based on the existing results of semigroup theory. The influence of the location of the boundary inputs on the transfer function representation is demonstrated. The pole-zero as well as frequency response analyses are also performed. The discussion is illustrated with a practical example of a shell and tube heat exchanger operating in parallel- and countercurrent-flow modes.
Descriptor fractional linear systems with regular pencils
Authors: Kaczorek Tadeusz
Published: October 2013

Methods for finding solutions of the state equations of descriptor fractional discrete-time and continuous-time linear systems with regular pencils are proposed. The derivation of the solution formulas is based on the application of the Z transform, the Laplace transform and the convolution theorems. Procedures for computation of the transition matrices are proposed. The efficiency of the proposed methods is demonstrated on simple numerical examples.
Asynchronous distributed state estimation for continuous-time stochastic processes
Authors: Kowalczuk Zdzisław , Domżalski Mariusz
Published: October 2013

The problem of state estimation of a continuous-time stochastic process using an Asynchronous Distributed multi-sensor Estimation (ADE) system is considered. The state of a process of interest is estimated by a group of local estimators constituting the proposed ADE system. Each estimator is based, e.g., on a Kalman filter and performs single sensor filtration and fusion of its local results with the results from other/remote processors to compute possibly the best state estimates. In performing data fusion, however, two important issues need to be addressed namely, the problem of asynchronism of local processors and the issue of unknown correlation between asynchronous data in local processors. Both the problems, along with their solutions, are investigated in this paper. Possible applications and effectiveness of the proposed ADE approach are illustrated by simulated experiments, including a non-complete connection graph of such a distributed estimation system.
An unconditionally stable nonstandard finite difference method applied to a mathematical model of HIV infection
Authors: Obaid Hasim A. , Ouifki Rachid , Patidar Kailash C.
Published: October 2013

We formulate and analyze an unconditionally stable nonstandard finite difference method for a mathematical model of HIV transmission dynamics. The dynamics of this model are studied using the qualitative theory of dynamical systems. These qualitative features of the continuous model are preserved by the numerical method that we propose in this paper. This method also preserves the positivity of the solution, which is one of the essential requirements when modeling epidemic diseases. Robust numerical results confirming theoretical investigations are provided. Comparisons are also made with the other conventional approaches that are routinely used for such problems.
A comparison of Jacobian-based methods of inverse kinematics for serial robot manipulators
Authors: Dulęba Ignacy , Opałka Michał
Published: October 2013

The objective of this paper is to present and make a comparative study of several inverse kinematics methods for serial manipulators, based on the Jacobian matrix. Besides the well-known Jacobian transpose and Jacobian pseudo-inverse methods, three others, borrowed from numerical analysis, are presented. Among them, two approximation methods avoid the explicit manipulability matrix inversion, while the third one is a slightly modified version of the Levenberg-Marquardt method (mLM). Their comparison is based on the evaluation of a short distance approaching the goal point and on their computational complexity. As the reference method, the Jacobian pseudo-inverse is utilized. Simulation results reveal that the modified Levenberg-Marquardt method is promising, while the first order approximation method is reliable and requires mild computational costs. Some hints are formulated concerning the application of Jacobian-based methods in practice.
State estimation for a class of nonlinear systems
Authors: Schwaller Benoît , Ensminger Denis , Dresp-Langley Birgitta , Ragot José
Published: October 2013

We propose a new type of Proportional Integral (PI) state observer for a class of nonlinear systems in continuous time which ensures an asymptotic stable convergence of the state estimates. Approximations of nonlinearity are not necessary to obtain such results, but the functions must be, at least locally, of the Lipschitz type. The obtained state variables are exact and robust against noise. Naslin’s damping criterion permits synthesizing gains in an algebraically simple and efficient way. Both the speed and damping of the observer response are controlled in this way. Model simulations based on a Sprott strange attractor are discussed as an example.
Double fault distinguishability in linear systems
Authors: Kościelny Jan Maciej , Łabęda-Grudziak Zofia M.
Published: October 2013

This paper develops a new approach to double fault isolation in linear systems with the aid of directional residuals. The method of residual generation for computational as well as internal forms is applied. Isolation of double faults is based on the investigation of the coplanarity of the residual vector with the planes defined by the individual pairs of directional fault vectors. Additionally, the method of designing secondary residuals, which are structured and directional, is proposed. These transformations allow achieving various isolation properties. It is shown that double fault distinguishability can be improved by decomposing the observed residual vector along the response directions. The described methods are illustrated with a simple computational example.
Generalized reasoning about faults based on the diagnostic matrix
Authors: Bartyś Michał
Published: October 2013

This paper introduces a set of comprehensive general reasoning rules about single faults based on a diagnostic matrix. The reasoning scheme unifies inference about faults based on a conventional binary diagnostic matrix, a two- and three-valued fault isolation system as well as on their fuzzy counterparts. There are introduced and defined notions of alternative and dominant fault signatures, fuzzy fault signatures as well as a matrix of alternative signatures. This matrix is supposed to be used instead of the classic diagnostic one. It is also shown that dominant fault signatures are transformable into alternative ones. Finally, three variants of concise general reasoning rules of faults are given. Three examples illustrate key point issues of the paper. The first example refers to a medical diagnostic case. It shows an instance of dominant fault signatures and, in fact, proposes a rational approach for planning diagnostic tests. The other examples describe the fuzzy reasoning approach employing a matrix of fuzzy alternative signatures applicable for use with multi-valued fuzzy diagnostic signals. Future works are outlined in the summary section.
Residual generator fuzzy identification for automotive diesel engine fault diagnosis
Authors: Simani Silvio
Published: October 2013

Safety in dynamic processes is a concern of rising importance, especially if people would be endangered by serious system failure. Moreover, as the control devices which are now exploited to improve the overall performance of processes include both sophisticated control strategies and complex hardware (input-output sensors, actuators, components and processing units), there is an increased probability of faults. As a direct consequence of this, automatic supervision systems should be taken into account to diagnose malfunctions as early as possible. One of the most promising methods for solving this problem relies on the analytical redundancy approach, in which residual signals are generated. If a fault occurs, these residual signals are used to diagnose the malfunction. This paper is focused on fuzzy identification oriented to the design of a bank of fuzzy estimators for fault detection and isolation. The problem is treated in its different aspects covering the model structure, the parameter identification method, the residual generation technique, and the fault diagnosis strategy. The case study of a real diesel engine is considered in order to demonstrate the effectiveness the proposed methodology.
Sensitivity of computer support game algorithms of safe ship control
Authors: Lisowski Józef
Published: October 2013

The paper investigates the sensitivity of safe ship control to inaccurate data from the ARPA anti-collision radar system and to changes in the process control parameters. The system structure of safe ship control in collision situations and computer support programmes exploring information from the ARPA anti-collision radar are presented. Sensitivity characteristics of the multistage positional non-cooperative and cooperative game and kinematics optimization control algorithms are determined through examples of navigational situations with restricted visibility at sea.
Linear discriminant analysis with a generalization of the Moore–Penrose pseudoinverse
Authors: Górecki Tomasz , Łuczak Maciej
Published: October 2013

The Linear Discriminant Analysis (LDA) technique is an important and well-developed area of classification, and to date many linear (and also nonlinear) discrimination methods have been put forward. A complication in applying LDA to real data occurs when the number of features exceeds that of observations. In this case, the covariance estimates do not have full rank, and thus cannot be inverted. There are a number of ways to deal with this problem. In this paper, we propose improving LDA in this area, and we present a new approach which uses a generalization of the Moore-Penrose pseudoinverse to remove this weakness. Our new approach, in addition to managing the problem of inverting the covariance matrix, significantly improves the quality of classification, also on data sets where we can invert the covariance matrix. Experimental results on various data sets demonstrate that our improvements to LDA are efficient and our approach outperforms LDA.
Approximation of fractional positive stable continuous-time linear systems by fractional positive stable discrete-time systems
Authors: Kaczorek Tadeusz
Published: October 2013

Fractional positive asymptotically stable continuous-time linear systems are approximated by fractional positive asymptotically stable discrete-time systems using a linear Padé-type approximation. It is shown that the approximation preserves the positivity and asymptotic stability of the systems. An optional system approximation is also discussed.
A simple scheme for semi-recursive identification of Hammerstein system nonlinearity by Haar wavelets
Authors: Śliwiński Przemysław , Hasiewicz Zygmunt , Wachel Paweł
Published: October 2013

A simple semi-recursive routine for nonlinearity recovery in Hammerstein systems is proposed. The identification scheme is based on the Haar wavelet kernel and possesses a simple and compact form. The convergence of the algorithm is established and the asymptotic rate of convergence (independent of the input density smoothness) is shown for piecewise- Lipschitz nonlinearities. The numerical stability of the algorithm is verified. Simulation experiments for a small and moderate number of input-output data are presented and discussed to illustrate the applicability of the routine.
A biochemical multi-species quality model of a drinking water distribution system for simulation and design
Authors: Arminski Krzysztof , Zubowicz Tomasz , Brdys Mietek A.
Published: October 2013

Drinking Water Distribution Systems (DWDSs) play a key role in sustainable development of modern society. They are classified as critical infrastructure systems. This imposes a large set of highly demanding requirements on the DWDS operation and requires dedicated algorithms for on-line monitoring and control to tackle related problems. Requirements on DWDS availability restrict the usability of the real plant in the design phase. Thus, a proper model is crucial. Within this paper a DWDS multi-species quality model for simulation and design is derived. The model is composed of multiple highly inter-connected modules which are introduced to represent chemical and biological species and (above all) their interactions. The chemical part includes the processes of chloramine decay with additional bromine catalysis and reaction with nitrogen compounds. The biological part consists of both heterotrophic and chemo-autotrophic bacteria species. The heterotrophic bacteria are assumed to consume assimilable organic carbon. Autotrophs are ammonia oxidizing bacteria and nitrite oxidizing bacteria species which are responsible for nitrification processes. Moreover, Disinfection By-Products (DBPs) are also considered. Two numerical examples illustrate the derived model’s behaviour in normal and disturbance operational states.
Controlling a non-homogeneous Timoshenko beam with the aid of the torque
Authors: Sklyar Grigory M. , Szkibiel Grzegorz
Published: October 2013

Considered is the control and stabilizability of a slowly rotating non-homogeneous Timoshenko beam with the aid of a torque. It turns out that the beam is (approximately) controllable with the aid of the torque if and only if it is (approximately) controllable. However, the controllability problem appears to be a side-effect while studying the stabilizability. To build a stabilizing control one needs to go through the methods of correcting the operators with functionals so that they have finally the appropriate form and the results on C0-continuous semigroups may be applied.