bluuebunny/crossref_metadata_2025 huggingface dataset:
Mg2+ Enhances Voltage Sensor/Gate Coupling in BK Channels
Authors: Horrigan Frank T. , Ma Zhongming
Published: December 2007

BK (Slo1) potassium channels are activated by millimolar intracellular Mg2+ as well as micromolar Ca2+ and membrane depolarization. Mg2+ and Ca2+ act in an approximately additive manner at different binding sites to shift the conductance–voltage (GK-V) relation, suggesting that these ligands might work through functionally similar but independent mechanisms. However, we find that the mechanism of Mg2+ action is highly dependent on voltage sensor activation and therefore differs fundamentally from that of Ca2+. Evidence that Ca2+ acts independently of voltage sensor activation includes an ability to increase open probability (PO) at extreme negative voltages where voltage sensors are in the resting state; 2 μM Ca2+ increases PO more than 15-fold at −120 mV. However 10 mM Mg2+, which has an effect on the GK-V relation similar to 2 μM Ca2+, has no detectable effect on PO when voltage sensors are in the resting state. Gating currents are only slightly altered by Mg2+ when channels are closed, indicating that Mg2+ does not act merely to promote voltage sensor activation. Indeed, channel opening is facilitated in a voltage-independent manner by Mg2+ in a mutant (R210C) whose voltage sensors are constitutively activated. Thus, 10 mM Mg2+ increases PO only when voltage sensors are activated, effectively strengthening the allosteric coupling of voltage sensor activation to channel opening. Increasing Mg2+ from 10 to 100 mM, to occupy very low affinity binding sites, has additional effects on gating that more closely resemble those of Ca2+. The effects of Mg2+ on steady-state activation and IK kinetics are discussed in terms of an allosteric gating scheme and the state-dependent interactions between Mg2+ and voltage sensor that may underlie this mechanism.
Disuse-induced Preferential Loss of the Giant Protein Titin Depresses Muscle Performance via Abnormal Sarcomeric Organization
Authors: Udaka Jun , Ohmori Shintaro , Terui Takako , Ohtsuki Iwao , Ishiwata Shin'ichi , Kurihara Satoshi , Fukuda Norio
Published: December 2007

Persistent muscle weakness due to disuse-associated skeletal muscle atrophy limits the quality of life for patients with various diseases and individuals who are confined to bed. Fibers from disused muscle exhibit a marked reduction in active force production, which can exacerbate motor function, coupled with the well-known loss of muscle quantity. Despite recent understanding of the signaling pathways leading to the quantity loss, the molecular mechanisms of the depressed qualitative performance still remain elusive. Here we show that long-term disuse causes preferential loss of the giant sarcomere protein titin, associated with changes in physiologic muscle function. Ca2+ sensitivity of active force decreased following 6 wk of hindlimb immobilization in the soleus muscle of the rat, accompanied by a shift in the length-active force relationship to the shorter length side. Our analyses revealed marked changes in the disused sarcomere, with shortening of thick and thin filaments responsible for altered length dependence and expansion of interfilament lattice spacing leading to a reduction in Ca2+ sensitivity. These results provide a novel view that disuse-induced preferential titin loss results in altered muscle function via abnormal sarcomeric organization.
Extended Use of Urinary Catheters in Older Surgical Patients: A Patient Safety Problem?
Authors: Wald Heidi L. , Epstein Anne M. , Radcliff Tiffany A. , Kramer Andrew M.
Published: December 2007

Objectives.

To explore the relationship between the extended postoperative use of indwelling urinary catheters and outcomes for older patients who have undergone cardiac, vascular, gastrointestinal, or orthopedic surgery in skilled nursing facilities and to describe patient and hospital characteristics associated with the extended use of indwelling urinary catheters.

Design.

Retrospective cohort study.

Setting.

US acute care hospitals and skilled nursing facilities.

Patients.

A total of 170,791 Medicare patients aged 65 years or more who were admitted to skilled nursing facilities after discharge from a hospital with a primary diagnosis code indicating major cardiac, vascular, orthopedic, or gastrointestinal surgery in 2001.

Main Outcome Measures.

Patient-specific 30-day rate of rehospitalization for urinary tract infection (UTI) and 30-day mortality rate, as well as the risk of having an indwelling urinary catheter at the time of admission to a skilled nursing facility.

Results.

A total of 39,282 (23.0%) of the postoperative patients discharged to skilled nursing facilities had indwelling urinary catheters. After adjusting for patient characteristics, the patients with catheters had greater odds of rehospitalization for UTI and death within 30 days than patients who did not have catheters. The adjusted odds ratios (aORs) for UTI ranged from 1.34 for patients who underwent gastrointestinal surgery (P<.001) to 1.85 for patients who underwent cardiac surgery (P<.001); the aORs for death ranged from 1.25 for cardiac surgery (P= .01) to 1.48 for orthopedic surgery (P= .002) and for gastrointestinal surgery (P< .001). After controlling for patient characteristics, hospitalization in the northeastern or southern regions of the United States was associated with a lower likelihood of having an indwelling urinary catheter, compared with hospitalization in the western region (P= .002 vsP= .03).

Conclusions.

Extended postoperative use of indwelling urinary catheters is associated with poor outcomes for older patients. The likelihood of having an indwelling urinary catheter at the time of discharge after major surgery is strongly associated with a hospital's geographic region, which reflects a variation in practice that deserves further study.
Randomized Controlled Trial and Meta-analysis of Oral Decontamination with 2% Chlorhexidine Solution for the Prevention of Ventilator-Associated Pneumonia
Authors: Tantipong Hutsaya , Morkchareonpong Chantana , Jaiyindee Songyod , Thamlikitkul Visanu
Published: December 2007

Objective.

To determine the effectiveness of oral decontamination with 2% chlorhexidine solution for the prevention of ventilator-associated pneumonia (VAP).

Design.

Randomized controlled trial and meta-analysis.

Setting.

A tertiary care university hospital in Bangkok, Thailand.

Participants.

Adult patients who received mechanical ventilation and who were hospitalized in intensive care units and general medical wards.

Methods.

The patients were randomized to receive oral decontamination with 2% chlorhexidine solution or normal saline solution 4 times per day until their endotracheal tubes were removed. The outcome measures were the development of VAP and oropharyngeal colonization with gram-negative bacilli. Meta-analysis was performed by combining the results of the present study with those from another randomized controlled trial that also used a 2% chlorhexidine formulation for oral decontamination.

Results.

The characteristics of the patients in the chlorhexidine group (n= 102) and the normal saline group (n= 105) were not significantly different. The incidence of VAP in the chlorhexidine group was 4.9% (5 of 102), and the incidence in the normal saline group was 11.4% (12 of 105) (P= .08). The rate of VAP in the chlorhexidine group was 7 episodes per 1,000 ventilator-days, and the rate in the normal saline group was 21 episodes per 1,000 ventilator-days (P= .04). Irritation of the oral mucosa was observed in 10 (9.8%) of the patients in the chlorhexidine group and in 1 (0.9%) of the patients in the normal saline group (P= .001). Oropharyngeal colonization with gram-negative bacilli was either reduced or delayed in the chlorhexidine group. Overall mortality of the patients did not differ significantly between the groups. Meta-analysis of 2 randomized controlled trials revealed an overall relative risk of VAP for patients in the chlorhexidine group of 0.53 (95% confidence interval, 0.31-0.90;P= .02).

Conclusion.

Oral decontamination with 2% chlorhexidine solution is an effective and safe method for preventing VAP in patients who receive mechanical ventilation.
UNIFORM DECAY PROPERTIES OF LINEAR VOLTERRA INTEGRO-DIFFERENTIAL EQUATIONS
Authors: CONTI MONICA , GATTI STEFANIA , PATA VITTORINO
Published: December 2007

We establish some new results concerning the exponential decay and the polynomial decay of the energy associated with a linear Volterra integro-differential equation of hyperbolic type in a Hilbert space, which is an abstract version of the equation [Formula: see text] describing the motion of linearly viscoelastic solids. We provide sufficient conditions for the decay to hold, without invoking differential inequalities involving the convolution kernel μ.
COMPOSITION FUNCTIONALS IN CALCULUS OF VARIATIONS: APPLICATION TO PRODUCTS AND QUOTIENTS
Authors: CASTILLO ENRIQUE , LUCEÑO ALBERTO , PEDREGAL PABLO
Published: December 2007

This paper deals with the problem of the Calculus of Variations for a functional which is the composition of a certain scalar function H with the integral of a vector valued field f, i.e. of the form [Formula: see text] where H : ℝn → ℝ and f : ℝ3 → ℝn. The integral of f is calculated here componentwise. We examine sufficient conditions for the existence of optimal solutions, and provide rules to obtain the necessary Euler–Lagrange, natural, transversality, Weierstrass–Erdmann and junction conditions for such a functional. Particular attention is paid to the cases of the product and the quotient as we take these as model situations. Finally, the theory is illustrated with a slope stability problem, and an example coming from Economics.
UNIFORM CONVERGENT MULTIGRID METHODS FOR ELLIPTIC PROBLEMS WITH STRONGLY DISCONTINUOUS COEFFICIENTS
Authors: XU JINCHAO , ZHU YUNRONG
Published: December 2007

This paper gives a solution to an open problem concerning the performance of various multilevel preconditioners for the linear finite element approximation of second-order elliptic boundary value problems with strongly discontinuous coefficients. By analyzing the eigenvalue distribution of the BPX preconditioner and multigrid V-cycle preconditioner, we prove that only a small number of eigenvalues may deteriorate with respect to the discontinuous jump or meshsize, and we prove that all the other eigenvalues are bounded below and above nearly uniformly with respect to the jump and meshsize. As a result, we prove that the convergence rate of the preconditioned conjugate gradient methods is uniform with respect to the large jump and meshsize. We also present some numerical experiments to demonstrate the theoretical results.
A RATE-INDEPENDENT MODEL FOR THE ISOTHERMAL QUASI-STATIC EVOLUTION OF SHAPE-MEMORY MATERIALS
Authors: AURICCHIO FERDINANDO , MIELKE ALEXANDER , STEFANELLI ULISSE
Published: December 2007

This paper addresses a three-dimensional model for isothermal stress-induced transformation in shape-memory polycrystalline materials. We treat the problem within the framework of the energetic formulation of rate-independent processes and investigate existence and continuous dependence issues at both the constitutive relation and quasi-static evolution level. Moreover, we focus on time and space approximation as well as on regularization and parameter asymptotics.
RELAXATION OF SOME TRANSVERSALLY ISOTROPIC ENERGIES AND APPLICATIONS TO SMECTIC A ELASTOMERS
Authors: ADAMS JAMES , CONTI SERGIO , DESIMONE ANTONIO , DOLZMANN GEORG
Published: December 2007

We determine the relaxation of some transversally-isotropic energy densities, i.e. functions W : ℝ3×3 → [0,∞] with the property W(QFR) = W(F) for all Q ∈ SO (3) and all R ∈ SO (3) such that Rn0 = n0, where n0 is a fixed unit vector. One physically relevant example is a model for smectic A elastomers. We discuss the implications of our result for the computation of macroscopic stress–strain curves for this material and compare with experiment.
A WORKFLOW FOR MUTATION EXTRACTION AND STRUCTURE ANNOTATION
Authors: KANAGASABAI RAJARAMAN , CHOO KHAR HENG , RANGANATHAN SHOBA , BAKER CHRISTOPHER J. O.
Published: December 2007

Rich information on point mutation studies is scattered across heterogeneous data sources. This paper presents an automated workflow for mining mutation annotations from full-text biomedical literature using natural language processing (NLP) techniques as well as for their subsequent reuse in protein structure annotation and visualization. This system, called mSTRAP (Mutation extraction and STRucture Annotation Pipeline), is designed for both information aggregation and subsequent brokerage of the mutation annotations. It facilitates the coordination of semantically related information from a series of text mining and sequence analysis steps into a formal OWL-DL ontology. The ontology is designed to support application-specific data management of sequence, structure, and literature annotations that are populated as instances of object and data type properties. mSTRAPviz is a subsystem that facilitates the brokerage of structure information and the associated mutations for visualization. For mutated sequences without any corresponding structure available in the Protein Data Bank (PDB), an automated pipeline for homology modeling is developed to generate the theoretical model. With mSTRAP, we demonstrate a workable system that can facilitate automation of the workflow for the retrieval, extraction, processing, and visualization of mutation annotations — tasks which are well known to be tedious, time-consuming, complex, and error-prone. The ontology and visualization tool are available at .
A STRUCTURAL BIOINFORMATICS APPROACH TO THE ANALYSIS OF NONSYNONYMOUS SINGLE NUCLEOTIDE POLYMORPHISMS (nsSNPs) AND THEIR RELATION TO DISEASE
Authors: WORTH CATHERINE L. , BICKERTON G. RICHARD J. , SCHREYER ADRIAN , FORMAN JULIA R. , CHENG TAMMY M. K. , LEE SEMIN , GONG SUNGSAM , BURKE DAVID F. , BLUNDELL TOM. L.
Published: December 2007

The prediction of the effects of nonsynonymous single nucleotide polymorphisms (nsSNPs) on function depends critically on exploiting all information available on the three-dimensional structures of proteins. We describe software and databases for the analysis of nsSNPs that allow a user to move from SNP to sequence to structure to function. In both structure prediction and the analysis of the effects of nsSNPs, we exploit information about protein evolution, in particular, that derived from investigations on the relation of sequence to structure gained from the study of amino acid substitutions in divergent evolution. The techniques developed in our laboratory have allowed fast and automated sequence-structure homology recognition to identify templates and to perform comparative modeling; as well as simple, robust, and generally applicable algorithms to assess the likely impact of amino acid substitutions on structure and interactions. We describe our strategy for approaching the relationship between SNPs and disease, and the results of benchmarking our approach — human proteins of known structure and recognized mutation.
TRANSCRIPT ANNOTATION PRIORITIZATION AND SCREENING SYSTEM (TrAPSS) FOR MUTATION SCREENING
Authors: O'LEARY BRIAN M. , DAVIS STEVEN G. , SMITH MICHAEL F. , BROWN BARTLEY , KEMP MATHEW B. , ALMABRAZI HAKEEM , GRUNDSTAD JASON A. , BURNS THOMAS , LEONTIEV VLADIMIR , ANDORF JEANEEN , CLARK ABBOT F. , SHEFFIELD VAL C. , CASAVANT THOMAS L. , SCHEETZ TODD E. , STONE EDWIN M. , BRAUN TERRY A.
Published: December 2007

When searching for disease-causing mutations with polymerase chain reaction (PCR)-based methods, candidate genes are usually screened in their entirety, exon by exon. Genomic resources (i.e. www.ncbi.nih.gov, www.ensembl.org, and genome.ucsc.edu) largely support this paradigm for mutation screening by making it easy to view and access sequence data associated with genes in their genomic context. However, the administrative burden of conducting mutation screening in potentially hundreds of genes and thousands of exons in thousands of patients is significant, even with the use of public genome resources. For example, the manual design of oligonucleotide primers for all exons of the 10 Leber's congenital amaurosis (LCA) genes (149 exons) represents a significant information management challenge. The Transcript Annotation Prioritization and Screening System (TrAPSS) is designed to accelerate mutation screening by (1) providing a gene-based local cache of candidate disease genes in a genomic context, (2) automating tasks associated with optimizing candidate disease gene screening and information management, and (3) providing the implementation of an algorithmic technique to utilize large amounts of heterogeneous genome annotation (e.g. conserved protein functional domains) so as to prioritize candidate genes.
RAPID PATTERN DEVELOPMENT FOR CONCEPT RECOGNITION SYSTEMS: APPLICATION TO POINT MUTATIONS
Authors: CAPORASO J. GREGORY , BAUMGARTNER WILLIAM A. , RANDOLPH DAVID A. , COHEN K. BRETONNEL , HUNTER LAWRENCE
Published: December 2007

The primary biomedical literature is being generated at an unprecedented rate, and researchers cannot keep abreast of new developments in their fields. Biomedical natural language processing is being developed to address this issue, but building reliable systems often requires many expert-hours. We present an approach for automatically developing collections of regular expressions to drive high-performance concept recognition systems with minimal human interaction. We applied our approach to develop MutationFinder, a system for automatically extracting mentions of point mutations from the text. MutationFinder achieves performance equivalent to or better than manually developed mutation recognition systems, but the generation of its 759 patterns has required only 5.5 expert-hours. We also discuss the development and evaluation of our recently published high-quality, human-annotated gold standard corpus, which contains 1,515 complete point mutation mentions annotated in 813 abstracts. Both MutationFinder and the complete corpus are publicly available at .
APPLICATION OF AUTOMATIC MUTATION–GENE PAIR EXTRACTION TO DISEASES
Authors: ERDOGMUS MUGE , SEZERMAN OSMAN UGUR
Published: December 2007

To have a better understanding of the mechanisms of disease development, knowledge of mutations and the genes on which the mutations occur is of crucial importance. Information on disease-related mutations can be accessed through public databases or biomedical literature sources. However, information retrieval from such resources can be problematic because of two reasons: manually created databases are usually incomplete and not up to date, and reading through a vast amount of publicly available biomedical documents is very time-consuming. In this paper, we describe an automated system, MuGeX (Mutation Gene eXtractor), that automatically extracts mutation–gene pairs from Medline abstracts for a disease query. Our system is tested on a corpus that consists of 231 Medline abstracts. While recall for mutation detection alone is 85.9%, precision is 95.9%. For extraction of mutation–gene pairs, we focus on Alzheimer's disease. The recall for mutation–gene pair identification is estimated at 91.3%, and precision is estimated at 88.9%. With automatic extraction techniques, MuGeX overcomes the problems of information retrieval from public resources and reduces the time required to access relevant information, while preserving the accuracy of retrieved information.
SEARCHING AND MINING VISUALLY OBSERVED PHENOTYPES OF MAIZE MUTANTS
Authors: SHYU CHI-REN , HARNSOMBURANA JATURON , GREEN JASON , BARB ADRIAN S. , KAZIC TONI , SCHAEFFER MARY , COE ED
Published: December 2007

There are thousands of maize mutants, which are invaluable resources for plant research. Geneticists use them to study underlying mechanisms of biochemistry, cell biology, cell development, and cell physiology. To streamline the understanding of such complex processes, researchers need the most current versions of genetic and physical maps, tools with the ability to recognize novel phenotypes or classify known phenotypes, and an intimate knowledge of the biochemical processes generating physiological and phenotypic effects. They must also know how all of these factors change and differ among species, diverse alleles, germplasms, and environmental conditions. While there are robust databases, such as MaizeGDB, for some of these types of raw data, other crucial components are missing. Moreover, the management of visually observed mutant phenotypes is still in its infant stage, let alone the complex query methods that can draw upon high-level and aggregated information to answer the questions of geneticists. In this paper, we address the scientific challenge and propose to develop a robust framework for managing the knowledge of visually observed phenotypes, mining the correlation of visual characteristics with genetic maps, and discovering the knowledge relating to cross-species conservation of visual and genetic patterns. The ultimate goal of this research is to allow a geneticist to submit phenotypic and genomic information on a mutant to a knowledge base and ask, "What genes or environmental factors cause this visually observed phenotype?".
TOWARDS A SYSTEMATIC EVALUATION OF PROTEIN MUTATION EXTRACTION SYSTEMS
Authors: WITTE RENÉ , BAKER CHRISTOPHER J. O.
Published: December 2007

The development of text analysis systems targeting the extraction of information about mutations from research publications is an emergent topic in biomedical research. Current systems differ in both scope and approach, thus preventing a meaningful comparison of their performance and therefore possible synergies. To overcome this evaluation bottleneck, we developed a comprehensive framework for the systematic analysis of mutation extraction systems, precisely defining tasks and corresponding evaluation metrics, that will allow a comparison of existing and future applications.
Substrate Effect on Plasma Clean Efficiency in Plasma Enhanced Chemical Vapor Deposition System
Authors: JangJian Shiu-Ko , Wang Ying-Lang
Published: December 2007

The plasma clean in a plasma-enhanced chemical vapor deposition (PECVD) system plays an important role to ensure the same chamber condition after numerous film depositions. The periodic and applicable plasma clean in deposition chamber also increases wafer yield due to less defect produced during the deposition process. In this study, the plasma clean rate (PCR) of silicon oxide is investigated after the silicon nitride deposited on Cu and silicon oxide substrates by remote plasma system (RPS), respectively. The experimental results show that the PCR drastically decreases with Cu substrate compared to that with silicon oxide substrate after numerous silicon nitride depositions. To understand the substrate effect on PCR, the surface element analysis and bonding configuration are executed by X-ray photoelectron spectroscopy (XPS). The high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) is used to analyze microelement of metal ions on the surface of shower head in the PECVD chamber. According to Cu substrate, the results show that micro Cu ion and theCuOxbonding can be detected on the surface of shower head. The Cu ion contamination might grab the fluorine radicals produced byNF3ddissociation in the RPS and that induces the drastic decrease on PCR.
Remarks on Extensions of the Himmelberg Fixed Point Theorem
Authors: Komiya Hidetoshi , Park Sehie
Published: December 2007

Recently, Jafari and Sehgal obtained an extension of the Himmelberg fixed point theorem based on the Kakutani fixed-point theorem. We give generalizations of the extension to almost convex sets instead of convex sets. We also give generalizations for a large class "Equation missing" of better admissible multimaps instead of the Kakutani maps. Our arguments are based on the KKM principle and some of previous results due to the second author.
Localization and Tracking of Passive RFID Tags Based on Direction Estimation
Authors: Zhang Yimin , Amin Moeness G. , Kaushik Shashank
Published: December 2007

Radio frequency identification (RFID) is poised for growth as businesses and governments explore applications implementing RFID. The RFID technology will continue to evolve to meet new demands for human and target location and tracking. In particular, there are increasing needs to locate and track multiple RFID-tagged items that are closely spaced. As a result, localization and tracking techniques with higher accuracy yet low implementation complexity are required. This paper examines the applicability of direction-of-arrival (DOA) estimation methods to the localization and tracking problems of passive RFID tags. Different scenarios of stationary and moving targets are considered. It is shown through performance analysis and simulation results that simple DOA estimation methods can be used to provide satisfactory localization performance.
The Structural Engineering Strategy for Photonic Material Research and Device Development
Authors: Lu Yalin
Published: December 2007

A new structural engineering strategy is introduced for optimizing the fabrication of arrayed nanorod materials, optimizing superlattice structures for realizing a strong coupling, and directly developing nanophotonic devices. The strategy can be regarded as “combinatorial” because of the high efficiency in optimizing structures. In this article, this strategy was applied to grow ZnO nanorod arrays, and to develop a new multifunctional photodetector using such nanorod arrays, which is able to simultaneously detect power, energy, and polarization of an incident ultraviolet radiation. The strategy was also used to study the extraordinary dielectric behavior of relaxor ferroelectric lead titanate doped lead magnesium niobate heterophase superlattices in the terahertz frequencies, in order to investigate their dielectric polariton physics and the potential to be integrated with tunable surface resonant plasmonics devices.
The Protecting Effects and Mechanisms of Baicalin and Octreotide on Heart Injury in Rats with SAP
Authors: Xiping Zhang , Hua Tian , Hanqing Chen , Li Chen , Zhiwei Wang , Keyi Wang , Wei Yan , Yun Li , Qingyu Li , Qing He , Fei Wang
Published: December 2007

Purpose.To observe the protecting effects and mechanisms of Baicalin and Octreotide on heart injury in rats with severe acute pancreatitis (SAP).Methods.The SAP rat models were randomly divided into the model group, Baicalin-treated group, Octreotide treated group, and sham operation group. The contents of some inflammatory indexes in blood were determined. The rat mortality, pathological changes of heart, the changes ofNF-κB, P-Selectin, Bax, Bcl-2, and Caspase-3 protein expression levels as well as apoptotic index were observed in all groups, respectively, at 3 hours, 6 hours, and 12 hours after operation.Results.The survival rate of model group was less than treated groups at 12 hours, difference was significant. The contents of some inflammatory indexes of the treated groups were lower than those of the model group to various degrees at different time points. The pathological myocardial changes under light microscope were milder in treated groups than in model group. The changes ofNF-κB, P-Selectin, Bax, Bcl-2, and Caspase-3 protein expression levels in all groups were different. There was only a case of myocardial cell apoptosis in an Octreotide-treated group at 6 hours.Conclusion.Baicalin and Octreotide have protecting effects on heart injury of rats with SAP.
A Perron-Frobenius Theorem for Positive Quasipolynomial Matrices Associated with Homogeneous Difference Equations
Authors: Anh Bui The , Thanh D. D. X.
Published: December 2007

We extend the classical Perron-Frobenius theorem for positive quasipolynomial matrices associated with homogeneous difference equations. Finally, the result obtained is applied to derive necessary and sufficient conditions for the stability of positive system.
Joint Optimization in UMTS-Based Video Transmission
Authors: Zsiros Attila , Fülöp Attila , Jeney Gábor
Published: December 2007

A software platform is exposed, which was developed to enable demonstration and capacity testing. The platform simulates a joint optimized wireless video transmission. The development succeeded within the frame of the IST-PHOENIX project and is based on the system optimization model of the project. One of the constitutive parts of the model, the wireless network segment, is changed to a detailed, standard UTRA network simulation module. This paper consists of (1) a brief description of the projects simulation chain, (2) brief description of the UTRAN system, and (3) the integration of the two segments. The role of the UTRAN part in the joint optimization is described, with the configuration and control of this element. Finally, some simulation results are shown. In the conclusion, we show how our simulation results translate into real-world performance gains.
Cellular Signaling and Potential New Treatment Targets in Diabetic Retinopathy
Authors: Khan Zia A. , Chakrabarti Subrata
Published: December 2007

Dysfunction and death of microvascular cells and imbalance between the production and the degradation of extracellular matrix (ECM) proteins are a characteristic feature of diabetic retinopathy (DR). Glucose‐induced biochemical alterations in the vascular endothelial cells may activate a cascade of signaling pathways leading to increased production of ECM proteins and cellular dysfunction/death. Chronic diabetes leads to the activation of a number of signaling proteins including protein kinase C, protein kinase B, and mitogen‐activated protein kinases. These signaling cascades are activated in response to hyperglycemia‐induced oxidative stress, polyol pathway, and advanced glycation end product formation among others. The aberrant signaling pathways ultimately lead to activation of transcription factors such as nuclear factor‐κB and activating protein‐1. The activity of these transcription factors is also regulated by epigenetic mechanisms through transcriptional coactivator p300. These complex signaling pathways may be involved in glucose‐induced alterations of endothelial cell phenotype leading to the production of increased ECM proteins and vasoactive effector molecules causing functional and structural changes in the microvasculature. Understanding of such mechanistic pathways will help to develop future adjuvant therapies for diabetic retinopathy.
Follow up after Primary Treatment of Soft Tissue Sarcoma: A Survey of Current Practice in the United Kingdom
Authors: Gerrand C. H. , Billingham L. J. , Woll P. J. , Grimer R. J.
Published: December 2007

Despite the clinical and financial implications, there is little evidence about how patients who have been treated for soft tissue sarcoma should be followed up. The purpose of this study was to determine current practice in the United Kingdom. 192 clinicians treating patients with soft tissue sarcoma were surveyed with a postal questionnaire enquiring about frequency and method of follow up and how patients would be followed up in each of 3 clinical scenarios: a patient with a trunk or extremity tumour at low risk of relapse; a patient with a trunk or extremity tumour at high risk of relapse; and a patient with a retroperitoneal or abdominal tumour. 155 (81%) clinicians responded. Clinic visits and X-rays were the most frequently used methods of follow up. Chest CT scans, local site imaging, and blood tests were used infrequently. The intensity and methods of follow up varied with each of the clinical scenarios. There was a seven-to-twenty fold variation in cost between the least and the most expensive regimes. Respondents were generally supportive of the development of the clinical trial in this area.
On the Dielectric and Magnetic Properties of Nanocomposites
Authors: Hallouet B. , Wetzel B. , Pelster R.
Published: December 2007

We investigate nanocomposites, that is, dispersions of magnetite nanoparticles in an epoxy resin, by means of broadband dielectric and magnetic spectroscopy. The molecular dynamics of the polymer matrix is altered by the nanoparticles. Due to the formation of agglomerates neither permittivity nor permeability can be described with known effective medium models. We use the spectral representation (Bergman theorem) to show that a model-free evaluation of the low-frequency permeability of the nanoparticles can be achieved by combining dielectric and magnetic data. In addition, the ferromagnetic resonance is studied experimentally. It occurs near 3 GHz and is independent of the particle concentration.
Silicon Thin-Film Solar Cells
Authors: Beaucarne Guy
Published: December 2007

We review the field of thin-film silicon solar cells with an active layer thickness of a few micrometers. These technologies can potentially lead to low cost through lower material costs than conventional modules, but do not suffer from some critical drawbacks of other thin-film technologies, such as limited supply of basic materials or toxicity of the components. Amorphous Si technology is the oldest and best established thin-film silicon technology. Amorphous silicon is deposited at low temperature
with plasma-enhanced chemical vapor deposition (PECVD). In spite of the fundamental limitation of this material due to its disorder and metastability, the technology is now gaining industrial momentum thanks to the entry of equipment manufacturers with experience with large-area PECVD. Microcrystalline Si (also called nanocrystalline Si) is a material with crystallites in the nanometer range in an amorphous matrix, and which contains less defects than amorphous silicon. Its lower bandgap makes it particularly appropriate as active material for the bottom cell in tandem and triple junction devices. The combination of an amorphous silicon top cell and a microcrystalline bottom cell has yielded promising results, but much work is needed to implement it on large-area and to limit light-induced degradation. Finally thin-film polysilicon solar cells, with grain size in the micrometer range, has recently emerged as an alternative photovoltaic technology. The layers have a grain size ranging from 1 μm to several tens of microns, and are formed at a temperature ranging from 600 to more than 1000∘C. Solid Phase Crystallization has yielded the best results so far but there has recently been fast progress with seed layer approaches, particularly those using the aluminum-induced crystallization technique.
Resonant Excitation of Terahertz Surface Plasmons in Subwavelength Metal Holes
Authors: Zhang Weili , Azad Abul K. , Han Jiaguang
Published: December 2007

We present a review of experimental studies of resonant excitation of terahertz surface plasmons in two-dimensional arrays of subwavelength metal holes. Resonant transmission efficiency higher than unity was recently achieved when normalized to the area occupied by the holes. The effects of hole shape, hole dimensions, dielectric function of metals, polarization dependence, and array film thickness on resonant terahertz transmission in metal arrays were investigated by the state-of-the-art terahertz time-domain spectroscopy. In particular, extraordinary terahertz transmission was demonstrated in arrays of subwavelength holes made even from Pb, a generally poor metal, and having thickness of only one-third of skin depth. Terahertz surface plasmons have potential applications in terahertz imaging, biosensing, interconnects, and development of integrated plasmonic components for terahertz generation and detection.
Anisotropic Left-Handed and μ-Negative Slab Waveguides: Physics and Device Applications
Authors: Salehi Hamidreza , Chaudhuri Sujeet K. , Mansour Raafat R.
Published: December 2007

We study the properties of various anisotropic left-handed slab waveguides. The analysis is extended to anisotropic μ-negative slab waveguides. The possible existence of the plasmon modes in various anisotropic slab waveguide configurations is discussed. An FDTD program is developed to investigate
the potential device applications of these anisotropic structures. A new signal detector and a two-channel
harmonic separator multiplexer are designed employing the μ-negative slab waveguide.
Effect of Irradiation Parameters on Morphology of Polishing DF2 (AISI-O1) Surface by Nd:YAG Laser
Authors: Guo Wei
Published: December 2007

Pulse Nd:YAG laser was used to polish DF2 cold work steel. Influence of irradiation parameters on the 3D surface morphology was studied by 3D profilometer, scanning electron microscopy (SEM), and atomic force microscope (AFM). Results among the tests showed when DF2 specimens were irradiated with parameters of (i) laser input energy P=1 J, (ii) pulse feedrate=300 mm/min, (iii) pulse duration (PD) =3 milliseconds, and (iv) pulse frequencyf=20∼25 Hz, laser polishing of DF2 cold work steel seemed to be successful.
Legendre's Differential Equation and Its Hyers-Ulam Stability
Authors: Jung Soon-Mo
Published: December 2007

We solve the nonhomogeneous Legendre's differential equation and apply this result to obtaining a partial solution to the Hyers-Ulam stability problem for the Legendre's equation.
Stability of a Second Order of Accuracy Difference Scheme for Hyperbolic Equation in a Hilbert Space
Authors: Ashyralyev Allaberen , Koksal Mehmet Emir
Published: December 2007

The initial-value problem for hyperbolic equation
d2u(t)/dt2+A(t)u(t)=f(t)(0≤t≤T), u(0)=ϕ,u′(0)=ψ in a Hilbert space H with the self-adjoint positive definite operators A(t) is considered. The second order of accuracy difference scheme for the approximately solving this initial-value problem is presented. The stability estimates for the solution of this difference scheme are established.
SBT Approach towards Analog Electronic Circuit Fault Diagnosis
Authors: Manikandan V. , Devarajan N.
Published: December 2007

An approach for the fault diagnosis of single and multiple faults in linear analog electronic circuits is proposed in this paper. The simulation-before-test (SBT) diagnosis approach proposed in this write up basically consists of obtaining the frequency response of fault free/faulty circuit. The peak frequency and the peak amplitude from the error response are observed and processed suitably to extract distinct signatures for faulty and nonfaulty conditions under maximum tolerance conditions for other network components. The artificial neural network classifiers are then used for the classification of fault. Networks of reasonable dimensions are shown to be capable of robust diagnosis of analog circuits including effects due to tolerances. This is a unique contribution of this paper. Fault computation time is drastically reduced from the traditional analysis techniques. This results in a direct dollar savings at test time. A comparison of the proposed work with the previous works which also employ preprocessing techniques, reveals that our algorithm performs significantly better in fault diagnosis of analog circuits due to our proposed preprocessing techniques.
Peroxisome Proliferator-Activated Receptor-γ(PPAR-γ) Agonists Attenuate the Profibrotic Response Induced by TGF-β1 in Renal Interstitial Fibroblasts
Authors: Wang Weiming , Liu Feng , Chen Nan
Published: December 2007

Background.Studies have shown that peroxisome proliferator-activated receptor-γ(PPAR-γ) agonists could ameliorate renal fibrotic lesions in both diabetic nephropathy and nondiabetic chronic kidney diseases. In order to elucidate the antifibrotic mechanism of PPAR-γagonists, we investigated the effects of PPAR-γactivation on TGF-β1-induced renal interstitial fibroblasts.Methods.In rat renal interstitial fibroblasts (NRK/49F), the mRNA expression of TGF-β1-inducedα-smooth muscle actin (α-SMA), connective tissue growth factor (CTGF), fibronectin (FN) and collagen type III (Col III) were observed by reverse transcriptase-polymerase chain reaction (RT-PCR). The protein expressions of FN and Smads were observed by Western blot.Results.In NRK/49F, TGF-β1 enhanced CTGF, FN and Col III mRNA expression in a dose- and time-dependent manner.α-SMA, CTGF, FN and Col III mRNA and FN protein expression in 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2)-troglitazone- and ciglitazone-pretreated groups, respectively, were significantly decreased compared with the TGF-β1-stimulated group. TGF-β1 (5 ng/mL) enhanced p-Smad2/3 protein expression in a time-dependent manner. Compared with the TGF-β1-stimulated group, p-Smad2/3 protein induced by TGF-β1 in PPAR-γagonists-pretreated groups significantly decreased with no statistical difference amongst the three pretreated groups.Conclusion.PPAR-γagonists could inhibit TGF-β1-induced renal fibroblast activation, CTGF expression and ECM synthesis through abrogating the TGF-β1/Smads signaling pathway.
Transmission Properties of Metallic Grating with Subwavelength Slits in THz Frequency Region
Authors: Liang Dong , Xing Qirong , Tian Zhen , Wang Changlei , Zhang Weili , Gu Jianqiang , Li Yanfeng , Chai Lu , Wang Qingyue , Zheltikov Aleksei
Published: December 2007

This paper presents a fully experimental and theoretical study on transmission properties of a deep metallic grating with subwavelength slits in THz frequency region by using THz time domain spectroscopy (THz-TDS). The grating exposed top-polarized incident wave exhibits enhanced nonresonant transmission in the long-wavelength region where the incident wavelength is larger than the grating period. Wood anomalies are observed when the wavelength is comparable to the grating period. Strict theory is given to explain the experimental results and the two are in good agreement. It is proposed that the Wood dips may be considered a criterion and a tool to judge and control the uniformity or fabricating accuracy of the grating period.
Mediators of Pruritus in Psoriasis
Authors: Reich Adam , Szepietowski Jacek C.
Published: December 2007

The pathogenesis of pruritus in psoriasis remains unclear. Many possible mediators were implicated to transmit or modulate this sensation in psoriasis, but none has been clearly proven to be a causative agent of itching. The most often discussed theory mentioned the importance of impaired innervations and neuropeptides imbalance in psoriatic skin. Other possible causes of itching might be increased expression of interleukin 2 or vascular abnormalities. Recent data indicated that pruritus could be also evoked by opioid system, prostanoids, interleukin 31, serotonin, or proteases. Whether these mechanisms are also involved in pruritus accompanying psoriasis requires further investigation. Limited knowledge of pruritus origin in psoriasis is responsible for the lack of the effective antipruritic treatments for psoriatics. Here, we summarize the current knowledge about the pathogenesis of pruritus in psoriasis and point out possible directions of future studies aiming the pathogenesis of this symptom in psoriasis.
Plutonium Isotopes Concentration in Seawater along the Algerian Coast
Authors: Benkrid M. , Noureddine A.
Published: December 2007

The International Atomic Energy Agency has organised in the framework of the regional project RAF/7/004, in collaboration with “Commissariat à l'Energie Atomique” (COMENA) and “Institut des Sciences de la Mer et de l'Aménagement du Littoral” (ISMAL), during August 2001, a scientific campaign along the Algerian coast, on board of the research vessel M.S. Benyahia of ISMAL is. Three stations, at the centre, east and west, were selected to collect five seawater samples for each water column reaching a maximum depth of 2000 m, using a stainless-steel water sampler of a volume of 250 litres. After recording the marine environment parameters (temperature and conductivity), seawater samples were conditioned and preconcentrated to precipitate plutonium isotopes usingMnCl2in the form ofMnO2in order to proceed to plutonium extraction by radiochemical separation and prepare the source by coprecipitation using neodymium fluoride (NdF3) by vacuum filtration and an evaluation of the activity by alpha spectrometry. Concentration results in units ofμBq/l of plutonium isotopes were obtained in the range of 6.7±1.00 to 25.5±3.70 forP239+240uand 0.21±0.04 to 0.77±0.15 forP238u. Distribution of Pu through the plot of its profile was studied and the concentration was estimated. The obtained results were compared toC137sand those found by other authors in the same Mediterranean area.
Protecting Effects of Dexamethasone on Thymus of Rats with Severe Acute Pancreatitis
Authors: Xiping Zhang , Li Chen , Miao Lin , Hua Tian
Published: December 2007

Purpose. To study the protecting effects of dexamethasone on thymus of rats with severe acute pancreatitis (SAP).Methods. The SAP rats were randomly assigned to the model group and dexamethasone-treated group, the other normal healthy rats were assigned to the sham operation group. The rat survival, thymus pathological changes, apoptotic index, as well as expression levels of NF-κB, P-selectin, Bax, Bcl-2, and Caspase-3 protein of all groups were observed, respectively, at 3 hours, 6 hours, and 12 hours. The contents of amylase and endotoxin in plasma as well as the contents of TNF-α,PLA2, and NO in serum were determined.Results. There was no marked difference between the model group and treated group in survival. The contents of different indexes in blood of treated group were lower than those of the model group to various degrees at different time points. The thymus pathological score was lower in treated group than in model group at 12 hours.The treated group in Caspase-3 protein expression of thymus significantly exceeded the model group at 12 hours. The apoptotic index was significantly higher in treated group than in model group.Conclusion. Dexamethasone has protecting effects on thymus of SAP rats.
Least Squares Fitting of Piecewise Algebraic Curves
Authors: Zhu Chun-Gang , Wang Ren-Hong
Published: December 2007

A piecewise algebraic curve is defined as the zero contour of a bivariate spline. In this paper, we present a new method for fittingC1piecewise algebraic curves of degree 2 over type-2 triangulation to the given scattered data. By simultaneously approximating points, associated normals and tangents, and points constraints, the energy term is also considered in the method. Moreover, some examples are presented.
Gas-Phase Photocatalytic Oxidation of Dimethylamine: The Reaction Pathway and Kinetics
Authors: Kachina Anna , Preis Sergei , Kallas Juha
Published: December 2007

Gas-phase photocatalytic oxidation (PCO) and thermal catalytic oxidation (TCO) of dimethylamine (DMA) on titanium dioxide was studied in a continuous flow simple tubular reactor. Volatile PCO products of DMA included ammonia, formamide, carbon dioxide, and water. Ammonia was further oxidized in minor amounts to nitrous oxide and nitrogen dioxide. Effective at 573 K, TCO resulted in the formation of ammonia, hydrogen cyanide, carbon monoxide, carbon dioxide, and water. The PCO kinetic data fit well to the monomolecular Langmuir-Hinshelwood model, whereas TCO kinetic behaviour matched the first-order process. No deactivation of the photocatalyst during the multiple long-run experiments was observed.