bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of Genes Important for Growth of Asymptomatic Bacteriuria Escherichia coli in Urine
Authors: Vejborg Rebecca M. , de Evgrafov Mari R. , Phan Minh Duy , Totsika Makrina , Schembri Mark A. , Hancock Viktoria
Published: July 2012

Escherichia coli
is the most important etiological agent of urinary tract infections (UTIs). Unlike uropathogenic
E. coli
, which causes symptomatic infections, asymptomatic bacteriuria (ABU)
E. coli
strains typically lack essential virulence factors and colonize the bladder in the absence of symptoms. While ABU
E. coli
can persist in the bladder for long periods of time, little is known about the genetic determinants required for its growth and fitness in urine. To identify such genes, we have employed a transposon mutagenesis approach using the prototypic ABU
E. coli
strain 83972 and the clinical ABU
E. coli
strain VR89. Six genes involved in the biosynthesis of various amino acids and nucleobases were identified (
carB
,
argE
,
argC
,
purA
,
metE
, and
ilvC
), and site-specific mutants were subsequently constructed in
E. coli
83972 and
E. coli
VR89 for each of these genes. In all cases, these mutants exhibited reduced growth rates and final cell densities in human urine. The growth defects could be complemented in
trans
as well as by supplementation with the appropriate amino acid or nucleobase. When assessed
in vivo
in a mouse model,
E. coli
83972
carAB
and 83972
argC
showed a significantly reduced competitive advantage in the bladder and/or kidney during coinoculation experiments with the parent strain, whereas 83972
metE
and 83972
ilvC
did not. Taken together, our data have identified several biosynthesis pathways as new important fitness factors associated with the growth of ABU
E. coli
in human urine.
Anaplasma phagocytophilum Dihydrolipoamide Dehydrogenase 1 Affects Host-Derived Immunopathology during Microbial Colonization
Authors: Chen Gang , Severo Maiara S. , Sakhon Olivia S. , Choy Anthony , Herron Michael J. , Felsheim Roderick F. , Wiryawan Hilda , Liao Jiayu , Johns Jennifer L. , Munderloh Ulrike G. , Sutterwala Fayyaz S. , Kotsyfakis Michail , Pedra Joao H. F.
Published: July 2012

Anaplasma phagocytophilum
is a tick-borne rickettsial pathogen that provokes an acute inflammatory response during mammalian infection. The illness caused by
A. phagocytophilum
, human granulocytic anaplasmosis, occurs irrespective of pathogen load and results instead from host-derived immunopathology. Thus, characterizing
A. phagocytophilum
genes that affect the inflammatory process is critical for understanding disease etiology. By using an
A. phagocytophilum
Himar1 transposon mutant library, we showed that a single transposon insertion into the
A. phagocytophilum
dihydrolipoamide dehydrogenase 1 gene (
lpda1
[
APH
_
0065
]) affects inflammation during infection.
A. phagocytophilum
lacking
lpda1
revealed enlargement of the spleen, increased splenic extramedullary hematopoiesis, and altered clinicopathological abnormalities during mammalian colonization. Furthermore, LPDA1-derived immunopathology was independent of neutrophil infection and correlated with enhanced reactive oxygen species from NADPH oxidase and nuclear factor (NF)-κB signaling in macrophages. Taken together, these findings suggest the presence of different signaling pathways in neutrophils and macrophages during
A. phagocytophilum
invasion and highlight the importance of LPDA1 as an immunopathological molecule.
Biofilm-Infected Intracerebroventricular Shunts Elicit Inflammation within the Central Nervous System
Authors: Snowden Jessica N. , Beaver Matt , Smeltzer Mark S. , Kielian Tammy
Published: July 2012

Central nervous system catheter infections are a serious complication in the treatment of hydrocephalus. These infections are commonly caused by
Staphylococcus epidermidis
and
Staphylococcus aureus
, both known to form biofilms on the catheter surface. Our objective was to generate a novel murine model of central nervous system catheter-associated biofilm infection using a clinical
S. aureus
isolate and characterize the nature of the inflammatory response during biofilm growth. Silicone catheters were precoated with
S. aureus
to facilitate bacterial attachment, whereupon infected or sterile catheters were stereotactically inserted into the lateral ventricle of the brain in C57BL/6 mice and evaluated at regular intervals through day 21 postinsertion. Animals tolerated the procedure well, with no clinical signs of illness or bacterial growth seen in the control group. Bacterial titers associated with central nervous system catheters were significantly elevated compared to those from the surrounding parenchyma, consistent with biofilm formation and minimal planktonic spread of infection. Catheter-associated bacterial burdens progressively increased, with maximal colonization achieved at day 7 postinfection. Analysis of inflammatory infiltrates by fluorescence-activated cell sorting (FACS) revealed significant macrophage and neutrophil influx, which peaked at days 3 and 5 to 7, respectively. In contrast, there were no detectable immune infiltrates associated with tissues surrounding sterile catheters. Biofilm infection led to significant increases in chemokine (CXCL1 and CCL2) and proinflammatory cytokine (interleukin 17 [IL-17]) expression in tissues surrounding infected central nervous system catheters. Based on these results, we propose this approach is a valid animal model for further investigations of catheter-associated central nervous system shunt infections.
Hcp2, a Secreted Protein of the Phytopathogen Pseudomonas syringae pv. Tomato DC3000, Is Required for Fitness for Competition against Bacteria and Yeasts
Authors: Haapalainen Minna , Mosorin Hanna , Dorati Federico , Wu Ru-Fen , Roine Elina , Taira Suvi , Nissinen Riitta , Mattinen Laura , Jackson Robert , Pirhonen Minna , Lin Nai-Chun
Published: June 2012

When analyzing the secretome of the plant pathogenPseudomonas syringaepv. tomato DC3000, we identified hemolysin-coregulated protein (Hcp) as one of the secreted proteins. Hcp is assumed to be an extracellular component of the type VI secretion system (T6SS). Two copies ofhcpgenes are present in theP. syringaepv. tomato DC3000 genome,hcp1(PSPTO_2539) andhcp2(PSPTO_5435). We studied the expression patterns of thehcpgenes and tested the fitness ofhcpknockout mutants in host plant colonization and in intermicrobial competition. We found that thehcp2gene is expressed most actively at the stationary growth phase and that the Hcp2 protein is secreted via the T6SS and appears in the culture medium as covalently linked dimers. Expression ofhcp2is not inducedin plantaand does not contribute to virulence in or colonization of tomato orArabidopsisplants. Instead,hcp2is required for survival in competition with enterobacteria and yeasts, and its function is associated with the suppression of the growth of these competitors. This is the first report on bacterial T6SS-associated genes functioning in competition with yeast. Our results suggest that the T6SS ofP. syringaemay play an important role in bacterial fitness, allowing this plant pathogen to survive under conditions where it has to compete with other microorganisms for resources.
Transcriptional Cross Talk within themar-sox-robRegulon in Escherichia coli Is Limited to therobandmarRABOperons
Authors: Chubiz Lon M. , Glekas George D. , Rao Christopher V.
Published: June 2012

Bacteria possess multiple mechanisms to survive exposure to various chemical stresses and antimicrobial compounds. In the enteric bacteriumEscherichia coli, three homologous transcription factors—MarA, SoxS, and Rob—play a central role in coordinating this response. Three separate systems are known to regulate the expression and activities of MarA, SoxS, and Rob. However, a number of studies have shown that the three do not function in isolation but rather are coregulated through transcriptional cross talk. In this work, we systematically investigated the extent of transcriptional cross talk in themar-sox-robregulon. While the three transcription factors were found to have the potential to regulate each other's expression when ectopically expressed, the only significant interactions observed under physiological conditions were betweenmarandrobsystems. MarA, SoxS, and Rob all activate themarRABpromoter, more so when they are induced by their respective inducers: salicylate, paraquat, and decanoate. None of the three proteins affects thesoxSpromoter, though unexpectedly, it was mildly repressed by decanoate by an unknown mechanism. SoxS is the only one of the three proteins to repress therobpromoter. Surprisingly, salicylate somewhat activates transcription ofrob, while decanoate represses it a bit. Rob, in turn, activates not only its downstream promoters in response to salicylate but also themarRABpromoter. These results demonstrate that themarandrobsystems function together in response to salicylate.
Fatty Acid Biosynthesis in Pseudomonas aeruginosa Is Initiated by the FabY Class of β-Ketoacyl Acyl Carrier Protein Synthases
Authors: Yuan Yanqiu , Sachdeva Meena , Leeds Jennifer A. , Meredith Timothy C.
Published: June 2012

The prototypical type II fatty acid synthesis (FAS) pathway in bacteria utilizes two distinct classes of β-ketoacyl synthase (KAS) domains to assemble long-chain fatty acids, the KASIII domain for initiation and the KASI/II domain for elongation. The central role of FAS in bacterial viability and virulence has stimulated significant effort toward developing KAS inhibitors, particularly against the KASIII domain of the β-acetoacetyl-acyl carrier protein (ACP) synthase FabH. Herein, we show that the opportunistic pathogen
Pseudomonas aeruginosa
does not utilize a FabH ortholog but rather a new class of divergent KAS I/II enzymes to initiate the FAS pathway. When a
P. aeruginosa
cosmid library was used to rescue growth in a
fabH
downregulated strain of
Escherichia coli
, a single unannotated open reading frame, PA5174, complemented
fabH
depletion. While deletion of all four KASIII domain-encoding genes in the same
P. aeruginosa
strain resulted in a wild-type growth phenotype, deletion of PA5174 alone specifically attenuated growth due to a defect in
de novo
FAS. Siderophore secretion and quorum-sensing signaling, particularly in the
rhl
and
Pseudomonas
quinolone signal (PQS) systems, was significantly muted in the absence of PA5174. The defect could be repaired by intergeneric complementation with
E. coli fabH
. Characterization of recombinant PA5174 confirmed a preference for short-chain acyl coenzyme A (acyl-CoA) substrates, supporting the identification of PA5174 as the predominant enzyme catalyzing the condensation of acetyl coenzyme A with malonyl-ACP in
P. aeruginosa
. The identification of the functional role for PA5174 in FAS defines the new FabY class of β-ketoacyl synthase KASI/II domain condensation enzymes.
Mortality with congenital heart defects in England and Wales, 1959–2009: exploring technological change through period and birth cohort analysis
Authors: Knowles Rachel L , Bull Catherine , Wren Christopher , Dezateux Carol
Published: June 2012

Background

Technological advances in surgery, intensive care and medical support have led to substantial decrease in mortality for children with congenital heart defects (CHDs) over the last 50 years.

Methods

Using routinely-collected mortality and population data for England and Wales from 1959 to 2009, the authors investigated age, period and birth cohort trends in child mortality attributable to CHDs.

Results

The total number of deaths with CHDs at all ages between 1959 and 2009 was 61 903 (33 929 (55%) males). Absolute numbers of CHD-related deaths in children (under age 15 years) fell from 1460 in 1959 to 154 in 2009. Infants (aged under 1 year) comprised over 60% of all deaths due to CHD during the 5-year period 1959–1963, but this fell to 22% by 2004–2008. Age-standardised death rates have declined for both sexes but, despite narrowing sex differences, males continue to have higher death rates. Successive birth cohorts have experienced improved death rates in the first year of life; however, declining mortality across all age-groups has only been observed for birth cohorts originating after 1989. Poisson regression modelling predicts continuing generational decline in mortality.

Conclusions

Death rates attributable to CHDs have fallen dramatically with advances in paediatric cardiac surgery and intensive care, largely due to decreased mortality in infants aged under 1 year. Initially, mortality in later childhood rose as infant deaths fell, suggesting death was delayed beyond infancy. Children born within the last 20 years experienced lower mortality throughout childhood.
Osteomyelitis of zygoma in a schizophrenia patient
Authors: Tomonori Mizutani , Hiroki Adachi , Masayuki Hojo
Published: July 2012

A 43-year-old man with schizophrenia presented to our hospital with appetite loss and general fatigue lasting 1–2 months. His face was flared and swollen, and he shed tears of pus. He could answer any questions, but never complained of pain. We found dacryocystitis with subcutaneous abscess with contiguous osteomyelitis with culture-provenStapylococcus aureus, and diabetes mellitus (DM). Although DM neuropathy was mild, he did not complain of pain. We searched thoroughly for other abscesses sinceS aureusgrew in all four of his blood cultures. We re-examined his whole body by CT, which revealed multiple muscle abscesses in both legs. It is reviewed that schizophrenia patients are relatively insensitive to physical pain. Thus, we should keep in mind that they may have multiple, unpredictable and rare underlying diseases, such as our case. Careful and thorough examinations are essential for treatment in schizophrenia patients.
A review of ballast water management practices and challenges in harsh and arctic environments
Authors: Jing Liang , Chen Bing , Zhang Baiyu , Peng Hongxuan
Published: July 2012

Ballast water is carried by cruise ships, large tankers, and bulk cargo carriers to acquire the optimum operating depth of the propeller and to maintain maneuverability and stability. Recently, ballast water has been recognized as wastewater that is responsible for ocean pollution due to the worldwide transfer of non-indigenous species, pathogenic bacteria, and other pollutants via ballast water discharge. This poses serious environmental, ecological, and economic threats to both coastal communities and the marine environment. To address these negative impacts and concerns, the International Maritime Organization (IMO) has codified and adopted a series of guidelines to minimize pollution and adverse effects caused by ballast water. A number of treatment technologies have been developed and applied in field practices to remove solids, particulates, organic pollutants, and organisms from ballast water, showing certain advantages and limitations. Many other management practices, such as ballast water exchange (BWE), shipping routes optimization, treatment process modeling, and risk assessment are in high demand to aid onboard treatment systems. However, knowledge and technical gaps still exist regarding the implementation of ballast water management practices especially in the context of arctic and harsh environments under changing climatic conditions. Records indicate that most coastal regions in the north have been invaded by unwanted species via ballast water discharge in the past decades. The North Atlantic and the Arctic Oceans have much colder climates and more extreme weather conditions than low latitudes. The discharge of untreated or less treated ballast water could cause much more severe damage to the local environment and hence pose higher risks to ecosystems and even human health, particularly in the context of climate change. Based on a comprehensive literature review, this study proposed a risk-based fuzzy–stochastic–interval programming decision support system to help eliminate environmental, ecological, as well as health threats from the discharge of ballast water, particularly in the north where weather, space, timing, maintenance, and cost are major concerns.
Increasing biological realism of fisheries stock assessment: towards hierarchical Bayesian methods
Authors: Kuparinen Anna , Mäntyniemi Samu , Hutchings Jeffrey A. , Kuikka Sakari
Published: July 2012

Excessively high rates of fishing mortality have led to rapid declines of several commercially important fish stocks. To harvest fish stocks sustainably, fisheries management requires accurate information about population dynamics, but the generation of this information, known as fisheries stock assessment, traditionally relies on conservative and rather narrowly data-driven modelling approaches. To improve the information available for fisheries management, there is a demand to increase the biological realism of stock-assessment practices and to better incorporate the available biological knowledge and theory. Here, we explore the development of fisheries stock-assessment models with an aim to increasing their biological realism, and focus particular attention on the possibilities provided by the hierarchical Bayesian modelling framework and ways to develop this approach as a means of efficiently incorporating different sources of information to construct more biologically realistic stock-assessment models. The main message emerging from our review is that to be able to efficiently improve the biological realism of stock-assessment models, fisheries scientists must go beyond the traditional stock-assessment data and explore the resources available in other fields of biological research, such as ecology, life-history theory and evolutionary biology, in addition to utilizing data available from other stocks of the same or comparable species. The hierarchical Bayesian framework provides a way of formally integrating these sources of knowledge into the stock-assessment protocol and to accumulate information from multiple sources and over time.
Relativistic study of the energy-dependent Coulomb potential including Coulomb-like tensor interaction
Authors: Hamzavi M. , Ikhdair S.M.
Published: July 2012

The exact Dirac equation for the energy-dependent Coulomb (EDC) potential including a Coulomb-like tensor (CLT) potential has been studied in the presence of spin and pseudospin symmetries with arbitrary spin–orbit quantum number, κ. The energy eigenvalues and corresponding eigenfunctions are obtained in the framework of the asymptotic iteration method. Some numerical results are obtained in the presence and absence of EDC and CLT potentials.
Modulational instability of electron-acoustic waves in plasmas with superthermal electrons
Authors: Eslami Parvin , Mottaghizadeh Marzieh , Pakzad Hamid Reza
Published: July 2012

The propagation of electron-acoustic waves (EAWs) in plasmas composed of inertial cold electrons, hot superthermal electrons, and stationary ions is investigated. By means of the reduction perturbation technique, a nonlinear Schrödinger equation is derived and the modulation instability of EAW is analyzed, where the superthermal parameter is found to be of significant importance. It is shown that the presence of superthermal electrons enhances the critical wave number of the modulational instability of EAWs. Besides, due to the presence of the superthermal electrons, EAWs are stable on a vaster region. Moreover, the modulational instability growth rate is lower for a larger population of superthermal electrons. Further, it is shown that increasing values of the relative density ratio α = ne0/nc0 shifts the instability domain to lower values of wave number k.
Symmetries, conservation laws, reductions, and exact solutions for the Klein–Gordon equation in de Sitter space–times
Authors: Jamal S. , Kara A.H. , Bokhari Ashfaque H.
Published: July 2012

In this paper, we complement the analysis involving the “fundamental” solutions of the Klein–Gordon equation in de Sitter space–times given by Yagdjian and A. Galstian (Comm. Math. Phys. 285, 293 (2009); Discrete and Continuous Dynamical Systems S, 2(3), 483 (2009)). Using the symmetry generators, we classify and reduce the underlying equations and show how this process may lead to exact solutions by quadratures.
Dust-acoustic waves in strongly coupled dusty plasmas with nonextensive electrons and ions
Authors: El-Awady E.I. , Djebli M.
Published: July 2012

The nonlinear features of dust-acoustic waves in a strongly coupled unmagnetized dusty plasma containing electrons and ions following q-nonextensive distribution, and negatively charged mobile dust are investigated by using the reductive perturbation method. The effects of important parameters, such as the q-parameter, temperature, density, and velocity on the properties of solitary and shock waves are discussed. The conditions for the formation of solitary structures and monotonic and oscillatory shock structures are also found. The implications of our result in space and laboratory dusty plasmas are discussed.
Generators of local supersymmetry transformation from first-class constraints
Authors: McKeon D.G.C.
Published: July 2012

We show how the generator of local supersymmetry transformations can be found from fermionic first-class constraints. This is done by adapting the approaches of Henneaux, Teitelboim and Zanelli, and of Castellani that have been used to find the generator of gauge transformations from bosonic first-class constraints. We illustrate how a supersymmetric gauge generator can be found by considering a spinning particle. The invariances that we find are not those presented in the original discussion of the spinning particle.
RANDOMIZED SELF-STABILIZING LEADER ELECTION IN PREFERENCE-BASED ANONYMOUS TREES
Authors: FAJARDO-DELGADO DANIEL , FERNÁNDEZ-ZEPEDA JOSÉ ALBERTO , BOURGEOIS ANU G.
Published: July 2012

The performance of processors in a distributed system can be measured by parameters such as bandwidth, storage capacity, work capability, reliability, power limitations, years of usage, among others. Each processor defines its preference based on these parameters. The preference represents an indicator of the quality of service that a processor can provide. An algorithm that follows a preference-based approach uses the preference of the processors to make decisions. In this paper we introduce a randomized self-stabilizing leader election algorithm for preference-based anonymous trees. Our algorithm assures that the processor with the highest preference in the system is always selected as the leader; moreover, it is able to solve symmetric configurations where each preference is the same. We prove that our algorithm has an optimal average time complexity and we also performed simulations to illustrate the average performance of the algorithm.
LABEL-GUIDED GRAPH EXPLORATION WITH ADJUSTABLE RATIO OF LABELS
Authors: HU LIANG , ZHANG MENG , ZHANG YI , TANG JIJUN
Published: July 2012

The graph exploration problem is to visit all the nodes of a connected graph by a mobile entity, e.g., a robot. The robot has no a priori knowledge of the topology of the graph or of its size. Cohen et al. [3] introduced label guided graph exploration which allows the system designer to add short labels to the graph nodes in a preprocessing stage; these labels can guide the robot in the exploration of the graph. In this paper, we address the problem of adjustable 1-bit label guided graph exploration. We focus on the labeling schemes that not only enable a robot to explore the graph but also allow the system designer to adjust the ratio of the number of different labels. This flexibility is necessary when maintaining different labels may have different costs or when the ratio is pre-specified. We present 1-bit labeling (two colors, namely black and white) schemes for this problem along with a labeling algorithm for generating the required labels. Given an n-node graph and a rational number ρ, we can design a 1-bit labeling scheme such that n/b ≥ ρ where b is the number of nodes labeled black. The robot uses O(ρ log Δ) bits of memory for exploring all graphs of maximum degree Δ. The exploration is completed in time [Formula: see text]. Moreover, our labeling scheme can work on graphs containing loops and multiple edges, while that of Cohen et al. focuses on simple graphs.
MINIMUM FEEDBACK ARC SETS IN ROTATOR AND INCOMPLETE ROTATOR GRAPHS
Authors: KUO CHI-JUNG , HSU CHIUN-CHIEH , LIN HON-REN , CHEN DA-REN
Published: July 2012

A feedback vertex/arc set (abbreviated as FVS/FAS) of a graph is a subset of the vertices/arcs which contains at least one vertex/arc for every cycle of that graph. A minimum FVS/FAS is an FVS/FAS which contains the smallest number of vertices/arcs. Hsu et al. [11] first proposed an algorithm which can find a minimum FVS in a rotator graph. In this paper, we present a formula for finding an FAS for a rotator graph and prove that the FAS is minimum. This formula can be easily implemented by an efficient algorithm which obtains a minimum FAS in a rotator graph. Finally, we also present a concise formula for finding a minimum FAS in an incomplete rotator graph in this paper.
VERTEX ISOPERIMETRIC PARAMETER OF A COMPUTATION GRAPH
Authors: RANJAN DESH , ZUBAIR MOHAMMAD
Published: July 2012

Let G = (V,E) be a computation graph, which is a directed graph representing a straight line computation and S ⊂ V. We say a vertex v is an input vertex for S if there is an edge (v, u) such that v ∉ S and u ∈ S. We say a vertex u is an output vertex for S if there is an edge (u, v) such that u ∈ S and v ∉ S. A vertex is called a boundary vertex for a set S if it is either an input vertex or an output vertex for S. We consider the problem of determining the minimum value of boundary size of S over all sets of size M in an infinite directed grid. This problem is related to the vertex isoperimetric parameter of a graph, and is motivated by the need for deriving a lower bound for memory traffic for a computation graph representing a financial application. We first extend the notion of vertex isoperimetric parameter for undirected graphs to computation graphs, and then provide a complete solution for this problem for all M. In particular, we show that a set S of size M = 3k2 + 3k + 1 vertices of an infinite directed grid, the boundary size must be at least 6k + 3, and this is obtained when the vertices in S are arranged in a regular hexagonal shape with side k + 1.
CODE SIZE REDUCTION FOR ARRAY INTENSIVE APPLICATIONS ON DIGITAL SIGNAL PROCESSORS
Authors: SALAMY HASSAN , RAMANUJAM J.
Published: July 2012

Optimizing the code size for applications that run on a digital signal processors (DSPs) is a crucial step in generating high-quality and efficient code. Most modern DSP provide multiple address registers and dedicated address generation units that provide address generation in parallel to instruction execution. There is no address computation overhead if the next address is within the auto-modify range of the address register. Many DSP algorithms have an iterative pattern of references to array elements within loops. Thus, a careful assignment of array references to address registers (called the address register allocation or ARA problem) reduces the number of explicit address arithmetic instructions as well as the execution cycles. In this paper, we present an optimal integer linear programming formulation for the address register allocation problem which incorporates code restructuring techniques. In addition, we have developed a Genetic Algorithm solution for the ARA problem that allows us to get near-optimal solutions in a reasonable amount of time for large embedded applications. Results on several benchmarks show the effectiveness of our techniques compared to other techniques in the literature.
A SURVEY OF ALGORITHMS AND ARCHITECTURES FOR H.264 SUB-PIXEL MOTION ESTIMATION
Authors: FATEMI MOHAMMAD REZA HOSSEINY , ATES HASAN F. , SALLEH ROSLI
Published: July 2012

This paper reviews recent state-of-the-art H.264 sub-pixel motion estimation (SME) algorithms and architectures. First, H.264 SME is analyzed and the impact of its functionalities on coding performance is investigated. Then, design space of SME algorithms is explored representing design problems, approaches, and recent advanced algorithms. Besides, design challenges and strategies of SME hardware architectures are discussed and promising architectures are surveyed. Further perspectives and future prospects are also presented to highlight emerging trends and outlook of SME designs.
A HIGH PRECISION CMOS VOLTAGE REFERENCE WITHOUT RESISTORS
Authors: ZHU ZHANGMING , WEI WEI , LIU LIANXI , YANG YINTANG
Published: July 2012

With the application of the voltage divider to the traditional bandgap reference without resistors, a high precision CMOS voltage reference without resistors has been proposed. The temperature coefficient has improved because the divider introduces the temperature compensation. The output reference voltage is 410.39 mV at the room temperature. The temperature coefficient of the voltage reference is 3.02 ppm/°C in the range from -20°C to 120°C. Moreover, the power supply rejection ratio of the voltage reference is -52.6 dB and the power consumption is 5.61 μW.
DOUBLE ZERO-POLE CANCELLATION FOR BANDWIDTH EXTENSION OF TRANSIMPEDANCE AMPLIFIERS
Authors: GHASEMI OMIDREZA
Published: July 2012

In this paper, double zero-pole cancellation for BandWidth (BW) extension of Transimpedance Amplifiers has been introduced. The effect of parasitic capacitances of the MOS transistor has been reduced using the mentioned approach. The process of zero-pole cancellation to extend the BW of the amplifier has been explained. To demonstrate the feasibility of the technique the transimpedance amplifier has been simulated in a well-known CMOS technology (i.e., 90 nm STMicroelectronics). It achieves 3 dB bandwidths of more than 46 GHz in the presence of 50 fF photodiode capacitance and 5 fF loading capacitance while only dissipating 4.06 mW.
AN INTEGRAL REGION CHOICE PROBLEM ON KNOT PROJECTION
Authors: AHARA KAZUSHI , SUZUKI MASAAKI
Published: July 2012

In this paper we propose a region choice problem for a knot projection. This problem is an integral extension of Shimizu's 'region crossing change unknotting operation.' We show that there exists a solution of the region choice problem for all knot projections.
THE PERFORMANCES OF TiN-TiB2 COATING PREPARED BY REACTIVE PLASMA SPRAYING
Authors: MA JING , HU JIANWEN , YAN DONGQING , MAO ZHENGPING
Published: July 2012

Reactive plasma sprayed coatings were prepared on carbon steel substrates with Ti and B4C as starting materials. Two kinds of gases ( Ar and N2 ) were used as feeding gases for powders, respectively. 10 wt.% Cr was added in the powders as binder to increase the bond strength of the coating. The phases, microstructure, micro-hardness and corrosion polarization behavior in 3.5 wt.% NaCl solution of the two coatings were studied. The results show that TiN-TiB2 coatings were prepared under both conditions. The two coatings have typically laminated structure. However, the coating prepared with Ar as feeding gas has higher porosity and some unmelted Cr particles. It also contains certain content of titanium oxides. The microhardness of coating prepared with Ar as feeding gas is lower due to its higher porosity, unmelted Cr particles and some amounts of TiO2 . The corrosion resistance of TiN-TiB2 coating prepared with Ar as feeding gas in 3.5 wt.% NaCl solution is worse than that of the coating prepared with N2 as feeding gas. Yet the corrosion resistance of reactive plasma sprayed TiN-TiB2 coating is improved greatly compared with that of carbon steel. The thermodynamic analysis of reactive plasma spraying process is also discussed.
INFLUENCE OF INTERFACE AND POLARIZATION ON MAGNETOELECTRIC COUPLING IN Ni-LEAD ZIRCONIUM TITANATE-Ni TRILAYERS DERIVED BY ELECTROLESS DEPOSITION
Authors: BI K. , WANG Y. G.
Published: July 2012

Magnetoelectric (ME) coupling in layered structures of magnetostrictive and piezoelectric phases are mediated by mechanical deformation and depends strongly on the interface conditions. Ni -lead zirconium titanate- Ni trilayers with neither electrodes nor bonding layers have been derived by electroless deposition. The structure of the electroless deposited Ni layer was characterized by X-ray diffraction. The cross-section of the Ni/PZT layers was investigated using scanning electron microscopy. The value of ME voltage coefficient (αE,31) increases as the interface roughness increases. The maximum of αE,31 for the Ni/PZT/Ni trilayers polarized after electroless deposition is higher than that for the Ni/PZT/Ni trilayers polarized before electroless deposition. It is essential to optimize the interface and the polarization to obtain higher ME voltage coefficient.
DISSOCIATION OF B2H6 AND ADSORPTION OF THE FRAGMENTS OF B2H6 ON THE STEPPED Ge(100) SURFACE
Authors: TÜRKMENOĞLU MUSTAFA , KATIRCIOĞLU ŞENAY
Published: July 2012

In this work, the p-type doping of the S A type stepped Ge(100) surface by a diborane ( B 2 H 6) gas flow has been simulated by the possible dissociation and adsorption models. The most probable dissociation model of B 2 H 6 and adsorption models of the fragments of B 2 H 6 on the stepped Ge(100) surface have been determined by the local minimum total energy and/or binding energy calculations based on the Density functional (B3LYP/6-3g) and Hartree–Fock (HF/STO-3g) theories, respectively. The present calculations have shown that, the step region (for both up and down terraces) of the stepped Ge(100) surface has the most attractive sites for BH3 molecules determined to be the first dissociation fragments of B 2 H 6 by an external energy of ~ 1.3 eV. It has been found that, at the first step of the adsorption, BH3 can dissociate to BH2 and BH fragments on the stepped Ge(100) surface. While BH3 and BH2 products prefer to be attached to a single surface Ge atom, BH is bridged between two adjacent surface Ge atoms. According to the present optimization calculations, the p-type doping process of the stepped Ge(100) surface has started with the adsorption of BH3 on the electron deficient site (buckled down) of the Ge dimer bond close to the step edge and ended with the substitutional occupation of the Ge site in the layers of the surface by B atom. The beginning of the p-type doping of the stepped Ge(100) surface has been illustrated by the electronic states of B appeared in the optical energy gap of Ge very close to the edge of the HOMO.
A DECISION SUPPORT SYSTEM FOR EXPOSITION TIMETABLING USING ANT COLONY OPTIMIZATION
Authors: LEE HSIN-YUN
Published: July 2012

The exposition industry has developed rapidly in recent years. For exposition centers, exposition timetabling is a complicated problem. The timetables arranged by the administrators usually result in an imbalanced usage percentage between showgrounds and a low total usage percentage for all showgrounds. In this paper, we developed a decision support system that considers the characteristics of exposition timetabling. The proposed system applies ant colony optimization for determining the near-optimal timetable of expositions. The ants are grouped into teams representing multi-layer ant paths for priority ranking. This improvement allows us to classify candidate expositions with different time preferences. The showground timetabling of an exposition center is used to validate the proposed system. The timetable proposed by the decision support system ensures a higher efficiency and a higher total usage percentage of the showgrounds than the timetable proposed by a human expert.
The (Common) Sense of KM
Authors: Koenig Michael E. D. , Jank David A.
Published: July 2012

In 2002, Tom Wilson argued about knowledge management (KM) "that the bandwagon lacks wheels". In the same issue of the same journal, Leonard Ponzi and Michael Koenig posited that KM was perhaps "in the process of establishing itself as a new aspect of management". Who was correct? This article examines bibliographic evidence to conclude that the latter interpretation was correct, that KM has firmly established itself as a major, and to the extent that permanence can be established in this rapidly changing world, permanent component of management. It then argues that the reasons for KM's permanence all fundamentally derive from the common sense of KM.
Tacit Knowledge Sharing During ERP Acquisition: An Exploratory Multi-Site Case Study
Authors: Palanisamy Ramaraj
Published: July 2012

Organisations that implement Enterprise Resources Planning (ERP) software packages are making a big commitment in terms of both time and money. Realising the ERP benefits, some organisations have successfully implemented while others have struggled, settled for minimum returns, and abandoned the system. To mitigate the risks, a knowledge sharing framework is suggested to be put in place during ERP acquisition. Based on findings in an explorative case study of three Canadian organisations that have gone through ERP acquisition phases, this study examines tacit knowledge sharing in ERP acquisition planning process, information search process, selection, evaluation, choice, and negotiations. The lessons learned and knowledge sharing activities are given by presenting a cross-comparison of the case studies.
AN EFFICIENT TECHNIQUE FOR SOLVING THE BLASZAK–MARCINIAK LATTICE BY COMBINING HOMOTOPY PERTURBATION AND PADÉ TECHNIQUES
Authors: YILDIRIM AHMET , KOÇAK HÜSEYIN
Published: July 2012

We combined the Homotopy perturbation method (HPM) and Padé techniques to solve the well-known Blaszak–Marciniak lattice. Blaszak–Marciniak lattice has rich mathematical structures and many important applications in physics, engineering and mathematics. Generally, the truncated series solution of HPM is adequate only in a small region when the exact solution is not reached. We overcame this limitation by using the Padé techniques, which have the advantage in turning the polynomials approximation into a rational function, are applied to the series solution to improve the accuracy and enlarge the convergence domain. Using this combined technique, the soliton solutions of the Blaszak–Marciniak lattice are constructed with better accuracy and better convergence than by using the HPM alone. An example of computed calculation is followed by comparative plots of the solutions obtained through the (HPM) and (HPM-Padé) methods. Graphics are gathered for discussion of convergence. The same protocol is applied to Blaszak–Marciniak four-field lattice.
THE EFFECT OF CERAMIC IN COMBINATION OF TWO SIGMOID FUNCTIONALLY GRADED ROTATING DISKS WITH VARIABLE THICKNESS
Authors: BAYAT M. , SAHARI B. B. , SALEEM M.
Published: July 2012

This paper presents elastic solutions of a disk made of functionally graded material (FGM) with variable thickness subjected to rotating load. The material properties are represented by combination of two sigmoid FGM (S-FGM) namely aluminum–ceramic–aluminum and the disk's different thickness profiles are assumed to be represented by power law distributions. Hollow disks are considered and the solutions for the displacements and stresses are given under appropriate boundary conditions. The effects of the material grading index n and the geometry of the disk on the displacements and stresses are investigated. The results are compared with the known results in the literature on metal–ceramic–metal FGMs. Also the solutions are compared S-FGM versus FGM and non FGM and variable thickness versus uniform thickness. It is found that a sigmoid functionally graded disk with concave thickness profile has smaller displacements and stresses compared with concave or linear thickness profile. It is also observed that an S-FGM rotating functionally graded disk with metal–ceramic–metal combination can be more efficient than the one with ceramic–metal or metal–ceramic.
INVESTIGATION OF SIZE EFFECTS ON STATIC RESPONSE OF SINGLE-WALLED CARBON NANOTUBES BASED ON STRAIN GRADIENT ELASTICITY
Authors: AKGÖZ B. , CİVALEK Ö.
Published: July 2012

This paper is concerned with the bending analysis of single-walled carbon nanotubes (CNT) based on modified couple stress and strain gradient elasticity theories and Euler–Bernoulli beam theory. The size effect is taken into consideration using the modified couple stress and strain gradient elasticity theories. The governing equations and boundary conditions are derived using the variational approach. Deflections of CNT are obtained and presented in graphical form. Results are presented to show the effect of small-scale effect on bending of CNT. It is the first time in the literature, analytical expression and their solutions for the bending analysis based on strain gradient elasticity and couple stress theories are given for CNT under uniformly distributed load and concentrated end load.
A NOVEL QUADRATIC EDGE-BASED SMOOTHED CONFORMING POINT INTERPOLATION METHOD (ES-CPIM) FOR ELASTICITY PROBLEMS
Authors: XU X. , LIU G. R. , GU Y. T.
Published: July 2012

This paper formulates an edge-based smoothed conforming point interpolation method (ES-CPIM) for solid mechanics using the triangular background cells. In the ES-CPIM, a technique for obtaining conforming PIM shape functions (CPIM) is used to create a continuous and piecewise quadratic displacement field over the whole problem domain. The smoothed strain field is then obtained through smoothing operation over each smoothing domain associated with edges of the triangular background cells. The generalized smoothed Galerkin weak form is then used to create the discretized system equations. Numerical studies have demonstrated that the ES-CPIM possesses the following good properties: (1) ES-CPIM creates conforming quadratic PIM shape functions, and can always pass the standard patch test; (2) ES-CPIM produces a quadratic displacement field without introducing any additional degrees of freedom; (3) The results of ES-CPIM are generally of very high accuracy.
Discotic liquid crystals of transition metal complexes 44: synthesis of hexaphenoxy-substituted phthalocyanine derivatives showing spontaneous perfect homeotropic alignment
Authors: Ariyoshi Masaaki , Sugibayashi-Kajita Makiko , Suzuki-Ichihara Ayumi , Kato Takayuki , Kamei Tenpei , Itoh Eiji , Ohta Kazuchika
Published: July 2012

We have synthesized novel hexaphenoxy-substituted phthalocyanine derivatives, 2-(12-hydroxydodecyloxy)-3-methoxy-9,10,16,17,23,24-hexakis(3,4-di-n-alkoxyphenoxy)phthalocyaninato copper(II) (abbreviated as Cn(OC12OH)PcCu : n = 10, 12, 14), and investigated their columnar mesomorphism and homeotropic alignment property. These hexaphenoxy-substituted Pc derivatives could be successfully isolated and purified from the mixture products by polarity difference. It was revealed by using polarizing optical microscopic observations, differential scanning calorimetry and temperature-dependent X-ray diffraction studies that each of the hexaphenoxy-substituted Pc derivatives has plural mesophases, and that the tetragonal columnar (Coltet) mesophase shows spontaneous perfect homeotropic alignment between two non-surface-treated glass plates without any defects and polydomain boundaries.
PHASE TRANSITION, DIELECTRIC AND PIEZOELECTRIC PROPERTIES OF NaNbO3–Ba0.85Ca0.15(Ti0.9Zr0.1)O3 LEAD-FREE CERAMICS
Authors: LEI YUQING , WU HONG , LIN DUNMIN , ZHENG QIAOJI , WU XIAOCHUN , FAN XIMING
Published: July 2012

A new lead-free solid solution of (1–x) NaNbO 3-x Ba 0.85 Ca 0.15( Ti 0.9 Zr 0.1) O 3 was prepared by a traditional sintering method and its phase transition, dielectric and piezoelectric properties were studied. Ba 0.85 Ca 0.15( Ti 0.9 Zr 0.1) O 3 diffuses into NaNbO3 lattices to form a new solid solution with perovskite structure. The addition of Ba 0.85 Ca 0.15( Ti 0.9 Zr 0.1) O 3(x≥0.025) transforms NaNbO3 from antiferroelectric to ferroelectric. The diffusive ferroelectric–paraelectric phase transition is induced in the ceramics with high concentration of Ba 0.85 Ca 0.15( Ti 0.9 Zr 0.1) O 3. The ceramics with x = 0.05–0.125 possess large Pr values of 18.6–25.5 μC/cm2. A morphotropic phase boundary between tetragonal and orthorhombic phases is formed at 0.05 < x < 0.15, leading to a significant enhancement of piezoelectric properties. The ceramic with x = 0.125 situated near the morphotropic phase boundary exhibits the optimum piezoelectric properties: d33 = 151 pC/N and kp = 31.6%.
System Personality and Persuasion in Human-Computer Dialogue
Authors: Andrews Pierre Y.
Published: July 2012

The human-computer dialogue research field has been studying interaction with computers since the early stage of Artificial Intelligence, however, research has often focused on very practical tasks to be completed with the dialogues. A new trend in the field tries to implement persuasive techniques with automated interactive agents; unlike booking a train ticket, for example, such dialogues require the system to show more anthropomorphic qualities. The influences of such qualities in the effectiveness of persuasive dialogue is only starting to be studied. In this article we focus on one important perceived trait of the system: personality, and explore how it influences the persuasiveness of a dialogue system. We introduce a new persuasive dialogue system and combine it with a state of the art personality utterance generator. By doing so, we can control the system’s extraversion personality trait and observe its influence on the user’s perception of the dialogue and its output. In particular, we observe that the user’s extraversion influences their perception of the dialogue and its persuasiveness, and that the perceived personality of the system can affect its trustworthiness and persuasiveness. We believe that theses observations will help to set up guidelines to tailor dialogue systems to the user’s interaction expectations and improve the persuasive interventions.
Type checking annotation-based product lines
Authors: Kästner Christian , Apel Sven , Thüm Thomas , Saake Gunter
Published: July 2012

Software product line engineering is an efficient means of generating a family of program variants for a domain from a single code base. However, because of the potentially high number of possible program variants, it is difficult to test them all and ensure properties like type safety for the entire product line. We present a product-line-aware type system that can type check an entire software product line without generating each variant in isolation. Specifically, we extend the Featherweight Java calculus with feature annotations for product-line development and prove formally that all program variants generated from a well typed product line are well typed. Furthermore, we present a solution to the problem of typing mutually exclusive features. We discuss how results from our formalization helped implement our own product-line tool CIDE for full Java and report of our experience with detecting type errors in four existing software product line implementations.
A logical verification methodology for service-oriented computing
Authors: Fantechi Alessandro , Gnesi Stefania , Lapadula Alessandro , Mazzanti Franco , Pugliese Rosario , Tiezzi Francesco
Published: July 2012

We introduce a logical verification methodology for checking behavioral properties of service-oriented computing systems. Service properties are described by means of SocL, a branching-time temporal logic that we have specifically designed for expressing in an effective way distinctive aspects of services, such as, acceptance of a request, provision of a response, correlation among service requests and responses, etc. Our approach allows service properties to be expressed in such a way that they can be independent of service domains and specifications. We show an instantiation of our general methodology that uses the formal language COWS to conveniently specify services and the expressly developed software tool CMC to assist the user in the task of verifying SocL formulas over service specifications. We demonstrate the feasibility and effectiveness of our methodology by means of the specification and analysis of a case study in the automotive domain.