bluuebunny/crossref_metadata_2025 huggingface dataset:
GxySBA ABC Transporter of Agrobacterium tumefaciens and Its Role in Sugar Utilization and
vir
Gene Expression
Authors: Zhao Jinlei , Binns Andrew N.
Published: June 2014

Monosaccharides available in the extracellular milieu of
Agrobacterium tumefaciens
can be transported into the cytoplasm, or via the periplasmic sugar binding protein, ChvE, play a critical role in controlling virulence gene expression. The ChvE-MmsAB ABC transporter is involved in the utilization of a wide range of monosaccharide substrates but redundant transporters are likely given the ability of a
chvE-mmsAB
deletion strain to grow, albeit more slowly, in the presence of particular monosaccharides. In this study, a putative ABC transporter encoded by the
gxySBA
operon is identified and shown to be involved in the utilization of glucose, xylose, fucose, and arabinose, which are also substrates for the ChvE-MmsAB ABC transporter. Significantly, GxySBA is also shown to be the first characterized glucosamine ABC transporter. The divergently transcribed gene
gxyR
encodes a repressor of the
gxySBA
operon, the function of which can be relieved by a subset of the transported sugars, including glucose, xylose, and glucosamine, and this substrate-induced expression can be repressed by glycerol. Furthermore, deletion of the transporter can increase the sensitivity of the virulence gene expression system to certain sugars that regulate it. Collectively, the results reveal a remarkably diverse set of substrates for the GxySBA transporter and its contribution to the repression of sugar sensitivity by the virulence-controlling system, thereby facilitating the capacity of the bacterium to distinguish between the soil and plant environments.
Analysis of Salmonella enterica Serovar Typhimurium Variable-Number Tandem-Repeat Data for Public Health Investigation Based on Measured Mutation Rates and Whole-Genome Sequence Comparisons
Authors: Dimovski Karolina , Cao Hanwei , Wijburg Odilia L. C. , Strugnell Richard A. , Mantena Radha K. , Whipp Margaret , Hogg Geoff , Holt Kathryn E.
Published: June 2014

Variable-number tandem repeats (VNTRs) mutate rapidly and can be useful markers for genotyping. While multilocus VNTR analysis (MLVA) is increasingly used in the detection and investigation of food-borne outbreaks caused by
Salmonella enterica
serovar Typhimurium (
S
. Typhimurium) and other bacterial pathogens, MLVA data analysis usually relies on simple clustering approaches that may lead to incorrect interpretations. Here, we estimated the rates of copy number change at each of the five loci commonly used for
S
. Typhimurium MLVA, during
in vitro
and
in vivo
passage. We found that loci STTR5, STTR6, and STTR10 changed during passage but STTR3 and STTR9 did not. Relative rates of change were consistent across
in vitro
and
in vivo
growth and could be accurately estimated from diversity measures of natural variation observed during large outbreaks. Using a set of 203 isolates from a series of linked outbreaks and whole-genome sequencing of 12 representative isolates, we assessed the accuracy and utility of several alternative methods for analyzing and interpreting
S
. Typhimurium MLVA data. We show that eBURST analysis was accurate and informative. For construction of MLVA-based trees, a novel distance metric, based on the geometric model of VNTR evolution coupled with locus-specific weights, performed better than the commonly used simple or categorical distance metrics. The data suggest that, for the purpose of identifying potential transmission clusters for further investigation, isolates whose profiles differ at one of the rapidly changing STTR5, STTR6, and STTR10 loci should be collapsed into the same cluster.
Chemosensory Regulation of a HEAT-Repeat Protein Couples Aggregation and Sporulation in Myxococcus xanthus
Authors: Darnell Cynthia L. , Wilson Janet M. , Tiwari Nitija , Fuentes Ernesto J. , Kirby John R.
Published: June 2014

Chemosensory systems are complex, highly modified two-component systems (TCS) used by bacteria to control various biological functions ranging from motility to sporulation. Chemosensory systems and TCS both modulate phosphorelays comprised of histidine kinases and response regulators, some of which are single-domain response regulators (SD-RRs) such as CheY. In this study, we have identified and characterized the Che7 chemosensory system of
Myxococcus xanthus
, a common soil bacterium which displays multicellular development in response to stress. Both genetic and biochemical analyses indicate that the Che7 system regulates development via a direct interaction between the SD-RR CheY7 and a HEAT repeat domain-containing protein, Cpc7. Phosphorylation of the SD-RR affects the interaction with its target, and residues within the α4-β5-α5 fold of the REC domain govern this interaction. The identification of the Cpc7 interaction with CheY7 extends the diversity of known targets for SD-RRs in biological systems.
Accumulation of Phosphatidic Acid Increases Vancomycin Resistance in Escherichia coli
Authors: Sutterlin Holly A. , Zhang Sisi , Silhavy Thomas J.
Published: June 2014

In Gram-negative bacteria, lipopolysaccharide (LPS) contributes to the robust permeability barrier of the outer membrane, preventing entry of toxic molecules such as antibiotics. Mutations in
lptD
, the beta-barrel component of the LPS transport and assembly machinery, compromise LPS assembly and result in increased antibiotic sensitivity. Here, we report rare vancomycin-resistant suppressors that improve barrier function of a subset of
lptD
mutations. We find that all seven suppressors analyzed mapped to the essential gene
cdsA
, which is responsible for the conversion of phosphatidic acid to CDP-diacylglycerol in phospholipid biosynthesis. These
cdsA
mutations cause a partial loss of function and, as expected, accumulate phosphatidic acid. We show that this suppression is not confined to mutations that cause defects in outer membrane biogenesis but rather that these
cdsA
mutations confer a general increase in vancomycin resistance, even in a wild-type cell. We use genetics and quadrupole time of flight (Q-TOF) liquid chromatography-mass spectrometry (LC-MS) to show that accumulation of phosphatidic acid by means other than
cdsA
mutations also increases resistance to vancomycin. We suggest that increased levels of phosphatidic acid change the physical properties of the outer membrane to impede entry of vancomycin into the periplasm, hindering access to its target, an intermediate required for the synthesis of the peptidoglycan cell wall.
Challenges of Using Molecular Serotyping for Surveillance of Pneumococcal Disease
Authors: Magomani Victoria , Wolter Nicole , Tempia Stefano , du Plessis Mignon , de Gouveia Linda , von Gottberg Anne
Published: June 2014

Recent advances in the molecular identification and serotyping of
Streptococcus pneumoniae
are useful for culture-negative samples; however, there are limitations associated with these methods. We aimed to assess the value of molecular assays for invasive pneumococcal disease (IPD) surveillance in South Africa from 2010 through 2012. Nonviable isolates and culture-negative clinical specimens were tested for the
lytA
gene and, if positive, were serotyped, using real-time PCRs. Multinomial regression analysis was used to determine the maximum
lytA
cycle threshold (

C
T

) value useful for predicting the ability to detect a serotype for the sample. The χ
2
test was used to compare the prevalence of serotypes between viable/nonviable isolates and culture-negative clinical specimens. Of 11,224 IPD cases reported, 1,091 (10%) were culture-negative samples and 981 (90%) of these were
lytA
positive. Samples with a

lytA C
T

value of ≥35 were significantly less likely to be serotyped. A serotype/group was determined for 87% (737/844) of samples with a

lytA C
T

value of <35, of which 60% (443/737) were identified as individual serotypes. The serotype prevalence did not differ significantly between isolates and culture-negative specimens. Although molecular serotyping added 7% (737/11,224) serotyping data, the inability to resolve 40% of samples to single serotypes remains a challenge for serotype-specific data analysis.
Hand and Nasal Carriage of Discordant Staphylococcus aureus Isolates among Urban Jail Detainees
Authors: David Michael Z. , Siegel Jane D. , Henderson Janet , Leos Greg , Lo Kaming , Iwuora Jerry , Taylor Alexis R. , Zychowski Diana L. , Porsa Esmaeil , Boyle-Vavra Susan , Daum Robert S.
Published: June 2014

In 928 Dallas County Jail detainees, nasal carriage of
Staphylococcus aureus
was found in 32.8% (26.5% methicillin-susceptible
Staphylococcus aureus
[MSSA] and 6.3% methicillin-resistant
S. aureus
[MRSA]), and hand carriage was found in 24.9% (20.7% MSSA and 4.1% MRSA). Among MRSA nasal carriers, 41% had hand MRSA carriage; 29% with hand MRSA carriage had no nasal
S. aureus
carriage. The prevalence of carriage was not associated with duration of the jail stay up to 180 days.
Staged off-pump coronary artery bypass grafting and radical nephrectomy in a patient with multivessel coronary artery disease and a renal tumour
Authors: Cetin Erdem , Ozyuksel Arda , Akay Ferruh
Published: June 2014

Coronary artery diseases and neoplastic disorders are the leading causes of morbidity and mortality in the elderly. Recently, controversial approaches have been raised about the treatment of cases with concomitant occurrence of coronary artery diseases and malignancies. The detrimental effects of cardiopulmonary bypass on neoplastic cells are always a challenge for such cases. We present a case of a large renal tumour associated with a recently symptomatic coronary artery disease which was successfully treated with staged off-pump coronary artery bypass grafting followed by radical nephrectomy. In such patients, off-pump revascularisation is favourable in order to decrease the risk of cancer spreading when compared to traditional on-pump cases. In our opinion, staged off-pump coronary arterial revascularisation followed by definitive surgical treatment for the malignancy is a safe and effective treatment modality in patients with coronary artery disease and oncological diseases.
Optical coherence tomography in a patient with congenital vitreous cyst
Authors: Dragnev Daniel , Shanmugalingam Sinnathamboo
Published: June 2014

A case of congenital vitreous cyst is presented. An optical coherence tomography scan has been performed, which has shown that the cyst is free floating and is multilobular. Its content was hyper-reflective.
Prevalence of dysglycemia in Calabar: a cross-sectional observational study among residents of Calabar, Nigeria
Authors: Enang O E , Otu A A , Essien O E , Okpara H , Fasanmade O A , Ohwovoriole A E , Searle J
Published: June 2014

Objective

Population data on dysglycemia are scarce in West Africa. This study aimed to determine the pattern of dysglycemia in Calabar city in South East Nigeria.

Design

This was a cross-sectional observational study.

Methods

1134 adults in Calabar were recruited. A multistage sampling method randomly selected 4 out of 22 wards, and 50 households from each ward. All adults within each household were recruited and an oral glucose tolerance test was performed. Dysglycemia was defined as any form of glucose intolerance, including: impaired fasting glucose (blood glucose level 110–125 mg/dL), impaired glucose tolerance (blood glucose level ≥140 mg/dL 2 h after consuming 75 g of glucose), or diabetes mellitus (DM), as defined by fasting glucose level ≥126 mg/dL, or a blood glucose level ≥200 mg/dL, 2 h after a 75 g glucose load.

Results

Mean values of fasting plasma glucose were 95 mg/dL (95% CI 92.1 to 97.5) for men and 96 mg/dL (95% CI 93.2 to 98.6) for women. The overall prevalence of dysglycemia was 24%. The prevalence of impaired fasting glucose was 9%, the prevalence of impaired glucose tolerance 20%, and the prevalence of undiagnosed DM 7%. All values were a few percentage points higher for men than women.

Conclusions

The prevalence of undiagnosed DM among residents of Calabar is similar to studies elsewhere in Nigeria but much higher than the previous national prevalence survey, with close to a quarter of the adults having dysglycemia and 7% having undiagnosed DM. This is a serious public health problem requiring a programme of mass education and case identification and management in all health facilities.

Trial registration number

CRS/MH/CR-HREC/020/Vol.8/43
Birth cohort study on the effects of desert dust exposure on children's health: protocol of an adjunct study of the Japan Environment & Children’s Study
Authors: Kanatani Kumiko T , Adachi Yuichi , Sugimoto Nobuo , Noma Hisashi , Onishi Kazunari , Hamazaki Kei , Takahashi Yoshimitsu , Ito Isao , Egawa Miho , Sato Keiko , Go Tohshin , Kurozawa Youichi , Inadera Hidekuni , Konishi Ikuo , Nakayama Takeo ,   Japan Environment & Children's Study Group
Published: June 2014

Introduction

Desert dust is estimated to constitute about 35% of aerosol in the troposphere. Desertification, climatic variability and global warming all can contribute to increased dust formation. This study aims to examine possible health effects of desert dust exposure on pregnant women and their children. The purpose of this report was to present the study protocol.

Methods and analysis

This 4-year birth cohort study began in 2011 as an adjunct study of the Japan Environment & Children’s Study (JECS) involving three regions: Kyoto, Toyama and Tottori. The JECS participants of the three regions above who also agreed to participate in this adjunct study were enrolled prior to delivery. Light Detecting and Ranging (LIDAR) with a polarisation analyser, which can distinguish mineral dust particles from other particles, is used for exposure measurements. Outcomes are allergic symptoms for mothers and development of asthma and other allergic or respiratory diseases for their children. Data are acquired in a timely manner by connecting local LIDAR equipment to an online questionnaire system. Participants answer the online questionnaire using mobile phones or personal computers.

Ethics and dissemination

The study protocol was approved by the ethics committees of Kyoto University, University of Toyama and Tottori University. All participants provided written informed consent. The results of this study will be published in peer-reviewed journals and disseminated to the scientific community and general public.

Trial Registration number

UMIN000010826.
Endoscopy management algorithms: role of cyanoacrylate glue injection and self-expanding metal stents in acute variceal haemorrhage
Authors: El Sayed G , Tarff S , O'Beirne J , Wright G
Published: June 2014

Mortality from acute variceal bleeding (AVB) has improved markedly over the last 2–3 decades due to increased specialisation and standardisation of medical and endoscopic practice culminating in the production of consensus guidance based on expert opinion. Nonetheless, despite greater exposure, training and endoscopic practices, 30-day mortality still remains high at around 30%. This is a reflection of the high morbidity with liver disease, and limited endoscopic experience and/or endoscopic techniques used by the majority of general endoscopists. Clinical necessity defines our drive for further endoscopic innovation to improve ‘best practice’ and, therefore, clinical outcomes accordingly. Sclerotherpy, variceal band ligation and/or rescue balloon tamponade have been entrenched in most treatment algorithms over the decades. However, in recent years and albeit limited to specialised liver centres, cyanoacrylate glue injection therapy (for oesophageal and gastric varices), and the placement of a self-expanding metallic stent for oesophageal varices have begun to offer improved endoscopic care in experienced hands. Yet even in specialised centres, their application is sporadic and operator dependent. Here, we discuss the evidence of these newer endoscopic approaches, and hope to propose their inclusion in endoscopic therapy algorithms for ‘best practice’ management of AVB in all appropriately supported endoscopy units.
Diagnostic and prognostic significance of CD200 expression and its stability in plasma cell myeloma
Authors: Douds Jonathan J , Long Daniel J , Kim Annette S , Li Shaoying
Published: June 2014

Aim

Previous studies showed that CD200 expression is a prognostic factor for plasma cell myeloma (PCM), but the prognostic effect is conflicting between studies. We studied CD200 protein expression and the stability of expression in PCM to clarify its potential utility in diagnosis, prognosis and monitoring of disease.

Method

CD200 expression was studied in 77 cases of PCM by immunohistochemistry on paraffin sections from decalcified bone marrow biopsies.

Result

There were 16 newly diagnosed cases and 61 post-treatment cases from 54 patients: 37 men and 17 women, with a median age of 62 years (range, 41–88 years). CD200 demonstrated moderate to strong membrane expression in positive cases. Fifty-six of 77 cases (73%) showed CD200 expression. Twenty of the 22 (91%) patients with serial specimens demonstrated stable CD200 expression (n=15) or lack of CD200 expression (n=5). One patient lost CD200 expression, while another one gained CD200 expression during treatment. The clinical, pathologic and cytogenetic features between the CD200+ group and the CD200− group were similar in most instances. However, CD200 expression was associated with lower serum β2-microglobulin (p=0.03). There was no significant difference in overall survival and progression-free survival between the CD200+ and CD200− patients (p>0.05).

Conclusions

CD200 is expressed in a majority of PCM cases, and the expression is stable during the treatment process. Therefore, immunohistochemical expression of CD200 is a useful marker for the diagnosis and follow-up of PCM.
Delayed fatherhood
Authors: Lawson Gerald , Fletcher Richard
Published: June 2014

Birth data from developed countries indicates that the average paternal age is increasing. As the trend to older fatherhood has become established, concerns have been raised that this may be linked to adverse outcomes, such as pregnancy complications, congenital anomalies, and long-term health implications for the child. Since the sperm of older fathers may be impaired due to the general effects of ageing, their offspring may be at risk due to defects in sperm quality at conception. A literature search was performed to identify pregnancy complications, fetal anomalies and health issues for the child when the father is in an older age bracket. Evidence for impairment in the sperm and genetic material of older fathers was reviewed. With an older father, there is evidence of an increase in stillbirths and a slightly increased risk of autism, bipolar disorder and schizophrenia in the offspring later in life. The increased risk of achondroplasia has long been recognised. For the mother, there is an increased rate of Caesarean section. Investigations of other possible adverse outcomes have produced mixed findings. Further robust and longitudinal studies are needed to clarify these issues.
Antimicrobial susceptibility and genetic characterisation of oxytetracycline‐resistant Edwardsiella tarda isolated from diseased eels
Authors: Lo D. Y. , Lee Y. J. , Wang J. H. , Kuo H. C.
Published: June 2014

Edwardsiellosis is one of the most important bacterial diseases in eels. Edwardsiella tarda (E. tarda) isolates (n=94) from diseased eels were screened against the eight most commonly used antimicrobial agents in aquaculture in Taiwan. These isolates were highly susceptible to ampicillin, amoxicillin, florfenicol, oxolinic acid and flumequine. In total, 20 of the 94 (21.3 per cent) isolates tested were resistant to oxytetracycline (OTC). Among the 20 tetracycline‐resistant E. tarda isolates, tet (A) was the predominant resistance determinant and was detected in 100 per cent of the isolates, whereas 90 per cent of these isolates carried the tet (M) determinant. The efflux pump inhibitor omeprazole reduced the minimum inhibitory concentrations (MICs) of OTC for these isolates by twofold to eightfold, suggesting that an intact efflux pump, presumably encoded by tet (A), is required for high‐level tetracycline resistance. Real‐time PCR experiments showed that increased expression levels of tet (A) and tet (R) could contribute to OTC resistance. Southern blot hybridisation also confirmed that the 20 OTC‐resistant E. tarda isolates all carried the TetA determinant on a plasmid that is approximately 50 or 70 kb in size, and restriction fragment length polymorphisms (RFLP) showed that the tet (A) gene was located on an 8–10 kb Eco RI fragment in all of these plasmids. The same plasmid type and RFLP patterns were detected across different farms in the same region, but differences in their pulsed‐field gel electrophoresis (PFGE) patterns were observed. This suggests a possible role for horizontal spreading and local transmission of the plasmid in the OTC‐resistant E. tarda population of eels from two different geographic origins.
Performance of micropiled raft in sand subjected to vertical concentrated load: centrifuge modeling
Authors: Alnuaim A.M. , El Naggar H. , El Naggar M.H.
Published: June 2014

Initial applications of micropiles have involved retrofitting foundations of existing buildings. In these applications, the overall performance of the micropiles–raft (MPR) foundation system is similar to a piled raft foundation where the load is transmitted through both the raft and micropiles. However, there is no guidance available regarding the performance of MPR foundations. In this study, geotechnical centrifuge testing was conducted to investigate the behavior of MPR foundations in sand and evaluate their performance characteristics. The study investigated the effect of raft flexibility on a number of important design parameters, including raft total and differential settlements, raft contact pressure, raft bending moment, and load sharing between the raft and micropiles. In addition, the use of micropiles as settlement reducers was investigated. The results showed that the micropiles carried 42%–59% of the applied load for the MPR configuration considered, which resulted in redistribution of the raft contact pressure. It was found that the Poulos–Davis–Randolph (PDR) method can be used to evaluate the performance of MPR systems with relatively stiff rafts; however, it is not applicable for MPR with flexible raft. A correction factor was proposed to account for the raft flexibility in the PDR method.
Theoretical study of 11-thiocyanatoundecanoic acid phenylamide derivatives on corrosion inhibition efficiencies
Authors: Sagdinc Seda , Kara Yesim , Kayadibi Filiz
Published: June 2014

Ab initio Hartree–Fock (HF) and Density Functional Theory (DFT) B3LYP methods with the 6-311G(d,p) basis set were applied to the three 11-thiocyanatoundecanoic acid phenylamide derivatives as corrosion inhibitors. Inhibition efficiency obtained experimentally followed the following order: N-(4-methoxyphenyl)-11-thiocyanatoundecanamide (N3MPTUA) > N-phenyl-11-thiocyanatoundecanamide (NPTUA) > N-(3-nitrophenyl)-11-thiocyanatoundecanamide (N3NPTUA). The molecular parameters most relevant to their potential action as corrosion inhibitors have been calculated in the neutral and protonated forms: EHOMO, ELUMO, energy gap (ΔE), dipole moment (μD), electronegativity (χ), global hardness (η), and the fraction of electrons transferred from the inhibitor molecule to the metallic atom (ΔN). The results of most of the global reactivity descriptors show that the experimental and theoretical studies agree well, and confirm that N3MPTUA is a better inhibitor than NPTUA or N3NPTUA. In addition, the local reactivity, analyzed through Fukui functions, show that the oxygen and nitrogen atoms will be the main adsorption sites.
Proteome phenotyping of ΔrelAmutants inEnterococcus faecalisV583
Authors: Yan Xue , Budin-Verneuil Aurélie , Auffray Yanick , Pichereau Vianney
Published: June 2014

The (p)ppGpp synthetase RelA contributes to stress adaptation and virulence in Enterococcus faecalis V583. A 2-dimensional electrophoresis proteomic analysis of 2 relA mutants, i.e., ΔrelA carrying a complete deletion of the relA gene, and ΔrelAsp that is deleted from only its 3′ extremity, showed that 31 proteins were deregulated in 1 or both of these mutants. Mass spectrometry identification of these proteins showed that 10 are related to translation, including 5 ribosomal proteins, 3 proteins involved in translation elongation, and 2 proteins in tRNA synthesis; 14 proteins are involved in diverse metabolisms and biosynthesis (8 in sugar and energy metabolisms, 2 in fatty acid biosynthesis, 2 in amino acid biosynthesis, and 2 in nucleotide metabolism). Five proteins were relevant to the adaptation to different environmental stresses, i.e., SodA and a Dps family protein, 2 cold-shock domain proteins, and Ef1744, which is a general stress protein that plays an important role in the response to ethanol stress. The potential role of these proteins in the development of stress phenotypes associated with these mutations is discussed.
Exercise and nutrition in myocardial matrix metabolism, remodeling, regeneration, epigenetics, microcirculation, and muscle
Authors: Tyagi Suresh C. , Joshua Irving G.
Published: June 2014

Remodeling and myocardial matrix metabolism contributes to cardiac endothelium–myocyte (perivascular fibrosis), myocyte–myocyte (interstitial fibrosis), and mitochondrion–myocyte (fusion and fission) coupling. Matrix metalloproteinases (MMPs), and tissue inhibitor of metalloproteinases (TIMPs) play differential roles in different tissues and diseases. For example, although present in the heart, MMP-3 is known as stromelysin (i.e., stromal tissue enzyme). Interestingly, TIMP-3 causes apoptosis. Exercise and nutrition are synergistic in the mitigation of diseases: exercise releases exosomes containing miRNAs. Nutrition/vitamins B6 and B12 regulate the metabolism of homocysteine (an epigenetic byproduct of DNA/RNA/protein methylation). Thus, epigenetic silencing is an important therapeutic target. The statistical analysis of cohorts may be less indicative for the treatment of a disease, particularly if the 2 twins are different in terms of responding to the medicine for the same disease, therefore, personalized medicine is the future of therapy.
DESIGN AND OPTIMIZATION OF A FULLY DIFFERENTIAL CMOS VARIABLE-GAIN LNA WITH DIFFERENTIAL EVOLUTION ALGORITHM FOR WLAN APPLICATIONS
Authors: ZIABAKHSH SOHEYL , ALAVI-RAD HOSEIN , AHANDANI MORTEZA ALINIA , YAGOUB MUSTAPHA C. E.
Published: June 2014

In this paper, we optimized the performance of a 2.4 GHz variable gain low-noise amplifier for WLAN applications which provides high dynamic range with relatively low power consumption. First, the differential evolution algorithm was used to optimize the width of input transistors, then the tunable on-chip switching stage method was applied to control the amplifier gain when the input signal increases. The optimization was performed in terms of gain, noise figure (NF), IIP3 and power dissipation. The LNA has achieved a variable gain from 16.55 to 20.45 dB with excellent NF between 1.63 and 1.74 dB. Furthermore, the proposed circuit achieves a third order input intercept point of 6.6 dBm. It consumes only 10 mW from a 1.5 V supply.
Chaotification of Impulsive Systems by Perturbations
Authors: Akhmet Marat , Fen Mehmet Onur
Published: June 2014

In this paper, we present a new method for chaos generation in nonautonomous impulsive systems. We prove the presence of chaos in the sense of Li–Yorke by implementing chaotic perturbations. An impulsive Duffing oscillator is used to show the effectiveness of our technique, and simulations that support the theoretical results are depicted. Moreover, a procedure to stabilize the unstable periodic solutions is proposed.
Clock-Driven Chaotic Pulse-Width Generators: An Overview and Demonstration of Power Supply Attack
Authors: Elwakil A. S.
Published: June 2014

This paper reviews pulse-excitation as a technique for inducing chaos and provides a review of circuits that have been designed based on this technique. A clock-driven chaotic van der Pol oscillator is also presented. Vulnerability of this class of chaos generators to power supply attacks is demonstrated.
Hidden Attractors and Dynamics of a General Autonomous van der Pol–Duffing Oscillator
Authors: Zhao Huitao , Lin Yiping , Dai Yunxian
Published: June 2014

In this paper, a general autonomous van der Pol–Duffing oscillator is studied. Several issues, such as periodic bifurcations and the dynamical structures of the system are investigated either analytically or numerically. Especially, a phenomenon of hidden attractors is noticed and an algorithm for the location of hidden attractors is given. The obtained results show that hidden attractors exist around chaotic attractors.
Bifurcation of Critical Periods from a Quartic Isochronous Center
Authors: Peng Linping , Feng Zhaosheng
Published: June 2014

This paper is focused on the bifurcation of critical periods from a quartic rigidly isochronous center under any small quartic homogeneous perturbations. By studying the number of zeros of the first several terms in the expansion of the period function in ε, it shows that under any small quartic homogeneous perturbations, up to orders 1 and 2 in ε, there are at most two critical periods bifurcating from the periodic orbits of the unperturbed system respectively, and the upper bound can be reached. Up to order 3 in ε, there are at most six critical periods from the periodic orbits of the unperturbed system. Moreover, we consider a family of perturbed systems of this quartic rigidly isochronous center, and obtain that up to any order in ε, there are at most two critical periods bifurcating from the periodic orbits of the unperturbed one, and the upper bound is sharp.
Managing Ambiguity When Evaluating and Selecting New Ideas in Project Portfolio Management
Authors: Gutiérrez Ernesto
Published: June 2014

Evaluating and selecting new ideas are central activities in project portfolio management (PPM). PPM dominant approach assumes that both ideas and decision criteria are clearly defined at their evaluation. It does not take into consideration ambiguous situations in which ideas are not fully understood, or there are opposing opinions about their potential. We explore evaluation of ideas when PPM decision makers experience ambiguity. We found that decision makers allow ideas to be developed further, which helps them to understand purposes, reveal benefits and construct judgments. However, it also affects resource allocation because it requires resources that had already been assigned.
Ranks of Submatrices in a Solution to a Consistent System of Linear Quaternion Matrix Equations with Applications
Authors: Lin Chunyan
Published: June 2014

Suppose that A1X=C1, XB2=C2, A3XB3=C3 is a consistent system of matrix equations and partition its solution X into a 2 × 2 block form. In this paper, we give formulas for the maximal and minimal ranks of the submatrices in a solution X to the system. We also investigate the uniqueness and the independence of submatrices in a solution X. As applications, we give some properties of submatrices in generalized inverses of matrices. These extend some known results in the literature.
An Abstract Construction of Vertex Algebras
Authors: Zhang Wei
Published: June 2014

In this paper, we introduce an abstract method of constructing vertex algebras which satisfy the C1-cofiniteness condition. We give some examples to explain how to use this abstract method.
On a Question of the Theory of Partially Composition Formations
Authors: Tsarev A. A. , Vorob'ev N. N.
Published: June 2014

Let n > 0 and ω be a non-empty set of primes. It is proved that the lattice of all τ-closed n-multiply ω-composition formations is inductive. It gives a positive answer to a question of Skiba asked in 2001 at the Gomel Algebraic Seminar.
Least-norm and Extremal Ranks of the Least Square Solution to the Quaternion Matrix Equation AXB=C Subject to Two Equations
Authors: Bao Yubao
Published: June 2014

In this paper, we give the expression of the least square solution of the linear quaternion matrix equation AXB=C subject to a consistent system of quaternion matrix equations D1X=F1, XE2=F2, and derive the maximal and minimal ranks and the least-norm of the above mentioned solution. The finding of this paper extends some known results in the literature.
A Note on $\mathcal{D}_{n}$-Testability for Varieties of Bands
Authors: Liu Guoxin , Yan Hongqin , Wang Zhengpan
Published: June 2014

Assume that [Formula: see text] is the variety of bands, and the identities of [Formula: see text] involve n variables (n ≥ 2). In this paper, we show that [Formula: see text] is [Formula: see text]-testable and is not [Formula: see text]-testable.
On Weakly Normal Subgroups of a Finite Group
Authors: Xu Yong , Zhang Xinjian , Zhao Tao
Published: June 2014

A subgroup H of a group G is said to be weakly normal in G if Hg≤ NG(H) implies that g ∈ NG(H). In this paper, using the condition that the minimal subgroups or subgroups of prime square order of G are weakly normal in G, we get some results about formation.
Development of highly sensitive mechanoluminescent sensor aiming at small strain measurement
Authors: Fujio Yuki , Xu Chao-Nan , Nishibori Maiko , Teraoka Yasutake , Kamitani Kazutaka , Terasaki Nao , Ueno Naohiro
Published: June 2014

This paper was focused on the elasticoluminescence (ELS) characteristics, especially a response to small strain (below 1000 μst), of mechanoluminescence (ML) sensor using strontium aluminate doped with small amount of europium ( SrAl 2 O 4: Eu ) synthesized by different methods. By using nitrate decomposition method as a synthetic method of SrAl 2 O 4: Eu , the response to small strain of the ML sensor was enhanced in comparison with using a conventional solid-state reaction method. Based on SEM observation and thermoluminescence (ThL) measurement, we proposed a hypothesis that the sensing characteristic of small strain affect the plate-like shape of SrAl 2 O 4: Eu grain and/or shallower carrier trap levels formed by nitrate decomposition method.
Challenges to global mineral resource security and options for future supply
Authors: Lusty P. A. J. , Gunn A. G.
Published: June 2014

Minerals are vital to support economic growth and the functioning of modern society. Demand for minerals is increasing as global population expands and minerals are used in a greater range of applications, particularly associated with the deployment of new technologies. While concerns about future mineral scarcity have been expressed, these are generally unfounded and based on over-simplistic analysis. This paper considers recent debate around security of mineral supply and technical, geosciences-based options to improve utilization of the resource base and contribute to replenishing reserves. History suggests that increasing demand for minerals and higher prices will generally lead to technological and scientific innovation that results in new or alternative sources of supply. Recent assessments of global mineral endowment suggest that society should be optimistic about its ability to meet future demand for minerals, provided that there is continued innovation and investment in science and technology. Reducing energy consumption and breaking the current link between metal production and greenhouse gas emissions are among the greatest challenges to secure a sustainable mineral supply. However, widespread adoption of low-carbon mineral extraction technologies, underpinned by multidisciplinary research, and increased global utilization of low-carbon energy sources will allow these challenges to be met.
Evaluating the impact of a late-burial corrosion model on reservoir permeability and performance in a mature carbonate field using near-wellbore upscaling
Authors: Chandra Viswasanthi , Wright Paul , Barnett Andrew , Steele Richard , Milroy Paul , Corbett Patrick , Geiger Sebastian , Mangione Alessandro
Published: June 2014

Field X comprises a giant Palaeogene limestone reservoir with a long production history. An original geomodel used for history matching employed a permeability transform derived directly from core data. However, the resulting permeability model required major modifications, such as horizontal and vertical permeability multipliers, in order to match the historic data. The rationale behind these multipliers is not well understood and not based on geological constraints. Our study employs an integrated near-wellbore upscaling workflow to identify and evaluate the geological heterogeneities that enhanced reservoir permeability. Key among these heterogeneities are mechanically weak zones of solution-enhanced porosity, leached stylolites and associated tension-gashes, which were developed during late-stage diagenetic corrosion. The results of this investigation confirmed the key role of diagenetic corrosion in enhancing the permeability of the reservoir. Insights gained from the available production history, in conjunction with petrophysical data analysis, substantiated the characterization of this solution-enhanced permeability. This study provided valuable insights into the means by which a satisfactory field-level history match for a giant carbonate reservoir can be achieved. Instead of applying artificial permeability multipliers that do not necessarily capture the impacts of geological heterogeneities, our method incorporates representations of fine-scale heterogeneities. Improving the characterization of permeability distribution in the field provided an updated and geologically consistent permeability model that could contribute to the ongoing development plans to maximize incremental oil recovery.
MOOCs on and off the Farm
Authors: Mitchell John C.
Published: June 2014

Whether MOOCs can provide a good education and broaden educational opportunities at lower cost is an ongoing discussion. In this article Stanford professor, John C. Mitchell, reflects on Stanford University's pioneering role in the MOOC movement, explains how to harness the power of digital technology, and offers predictions for the academic landscape.
Splitting Arabic Texts into Elementary Discourse Units
Authors: Keskes Iskandar , Zitoune Farah Benamara , Belguith Lamia Hadrich
Published: June 2014

In this article, we propose the first work that investigates the feasibility of Arabic discourse segmentation into elementary discourse units within the segmented discourse representation theory framework. We first describe our annotation scheme that defines a set of principles to guide the segmentation process. Two corpora have been annotated according to this scheme: elementary school textbooks and newspaper documents extracted from the syntactically annotated Arabic Treebank. Then, we propose a multiclass supervised learning approach that predicts nested units. Our approach uses a combination of punctuation, morphological, lexical, and shallow syntactic features. We investigate how each feature contributes to the learning process. We show that an extensive morphological analysis is crucial to achieve good results in both corpora. In addition, we show that adding chunks does not boost the performance of our system.
TALIP Perspectives, Guest Editorial Commentary
Authors: Rubin Victoria L.
Published: June 2014

In hopes of sparking a discussion, I argue for much needed research on automated deception detection in Asian languages. The task of discerning truthful texts from deceptive ones is challenging, but a logical sequel to opinion mining. I suggest that applied computational linguists pursue broader interdisciplinary research on cultural differences and pragmatic use of language in Asian cultures, before turning to detection methods based on a primarily Western (English-centric) worldview. Deception is fundamentally human, but how do various cultures interpret and judge deceptive behavior?
Curricular Technology Transfer for the 21st Century
Authors: Fox Armando
Published: June 2014

Is the MOOC honeymoon winding down? With many university faculty opposing the MOOC movement, the author argues taking the best of massive online courses access to high-quality materials and rapid feedback to students to implement SPOCs (small private online courses) will provide a more effective leverage of instructors' time and resources.
Daredevil
Authors: Constandache Ionut , Agarwal Sharad , Tashev Ivan , Choudhury Romit Roy
Published: June 2014

A variety of techniques have been used by prior work on the problem of smartphone location. In this paper, we propose a novel approach using sound source localization (SSL) with microphone arrays to determine where in a room a smartphone is located. In our system called Daredevil, smartphones emit sound at particular times and frequencies, which are received by microphone arrays. Using SSL that we modified for our purposes, we can calculate the angle between the center of each microphone array and the phone, and thereby triangulate the phone's position. In this early work, we demonstrate the feasibility of our approach and present initial results. Daredevil can locate smartphones in a room with an average precision of 3.19 feet. We identify a number of challenges in realizing the system in large deployments, and we hope this work will benefit researchers who pursue such techniques.
Intrinsic aerobic capacity impacts susceptibility to acute high-fat diet-induced hepatic steatosis
Authors: Matthew Morris E. , Jackman Matthew R. , Johnson Ginger C. , Liu Tzu-Wen , Lopez Jordan L. , Kearney Monica L. , Fletcher Justin A. , Meers Grace M. E. , Koch Lauren G. , Britton Stephen L. , Scott Rector R. , Ibdah Jamal A. , MacLean Paul S. , Thyfault John P.
Published: June 2014

Aerobic capacity/fitness significantly impacts susceptibility for fatty liver and diabetes, but the mechanisms remain unknown. Herein, we utilized rats selectively bred for high (HCR) and low (LCR) intrinsic aerobic capacity to examine the mechanisms by which aerobic capacity impacts metabolic vulnerability for fatty liver following a 3-day high-fat diet (HFD). Indirect calorimetry assessment of energy metabolism combined with radiolabeled dietary food was employed to examine systemic metabolism in combination with ex vivo measurements of hepatic lipid oxidation. The LCR, but not HCR, displayed increased hepatic lipid accumulation in response to the HFD despite both groups increasing energy intake. However, LCR rats had a greater increase in energy intake and demonstrated greater daily weight gain and percent body fat due to HFD compared with HCR. Additionally, total energy expenditure was higher in the larger LCR. However, controlling for the difference in body weight, the LCR has lower resting energy expenditure compared with HCR. Importantly, respiratory quotient was significantly higher during the HFD in the LCR compared with HCR, suggesting reduced whole body lipid utilization in the LCR. This was confirmed by the observed lower whole body dietary fatty acid oxidation in LCR compared with HCR. Furthermore, LCR liver homogenate and isolated mitochondria showed lower complete fatty acid oxidation compared with HCR. We conclude that rats bred for low intrinsic aerobic capacity show greater susceptibility for dietary-induced hepatic steatosis, which is associated with a lower energy expenditure and reduced whole body and hepatic mitochondrial lipid oxidation.
Quantification of Photocyanine in Human Serum by High-Performance Liquid Chromatography-Tandem Mass Spectrometry and Its Application in a Pharmacokinetic Study
Authors: Bi Bing-Tian , Zou Ben-Yan , Deng Li-Ting , Zhan Jing , Liao Hai , Feng Kun-Yao , Li Su
Published: June 2014

Photocyanine is a novel anticancer drug. Its pharmacokinetic study in cancer patients is therefore very important for choosing doses, and dosing intervals in clinical application. A rapid, selective and sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed and validated for the determination of photocyanine in patient serum. Sample preparation involved one-step protein precipitation by adding methanol and N,N-dimethyl formamide to 0.1 mL serum. The detection was performed on a triple quadrupole tandem mass spectrometer operating in multiple reaction-monitoring (MRM) mode. Each sample was chromatographed within 7 min. Linear calibration curves were obtained for photocyanine at a concentration range of 20–2000 ng/mL (r>0.995), with the lower limit of quantification (LLOQ) being 20 ng/mL. The intrabatch accuracy ranged from 101.98% to 107.54%, and the interbatch accuracy varied from 100.52% to 105.62%. Stability tests showed that photocyanine was stable throughout the analytical procedure. This study is the first to utilize the HPLC-MS/MS method for the pharmacokinetic study of photocyanine in six cancer patients who had received a single dose of photocyanine (0.1 mg/kg) administered intravenously.
Metformin against Cancer Stem Cells through the Modulation of Energy Metabolism: Special Considerations on Ovarian Cancer
Authors: Kim Tae Hun , Suh Dong Hoon , Kim Mi-Kyung , Song Yong Sang
Published: June 2014

Ovarian cancer is the most lethal gynecologic malignancy among women worldwide and is presumed to result from the presence of ovarian cancer stem cells. To overcome the limitation of current anticancer agents, another anticancer strategy is necessary to effectively target cancer stem cells in ovarian cancer. In many types of malignancies, including ovarian cancer, metformin, one of the most popular antidiabetic drugs, has been demonstrated to exhibit chemopreventive and anticancer efficacy with respect to incidence and overall survival rates. Thus, the metabolic reprogramming of cancer and cancer stem cells driven by genetic alterations during carcinogenesis and cancer progression could be therapeutically targeted. In this review, the potential efficacy and anticancer mechanisms of metformin against ovarian cancer stem cells will be discussed.
Using the ACS Approach to Solve Continuous Mathematical Problems in Engineering
Authors: Wu Min-Thai , Hong Tzung-Pei , Lee Chung-Nan
Published: June 2014

Ant colony system (ACS) has been widely applied for solving discrete domain problems in recent years. In particular, they are efficient and effective in finding nearly optimal solutions to discrete search spaces. Because of the restriction of ant‐based algorithms, when the solution space of a problem to be solved is continuous, it is not so appropriate to use the original ACS to solve it. However, engineering mathematics in the real applications are always applied in the continuous domain. This paper thus proposes an extended ACS approach based on binary‐coding to provide a standard process for solving problems with continuous variables. It first encodes solution space for continuous domain into a discrete binary‐coding space (searching map), and a modified ACS can be applied to find the solution. Each selected edge in a complete path represents a part of a candidate solution. Different from the previous ant‐based algorithms for continuous domain, the proposed binary coding ACS (BCACS) could retain the original operators and keep the benefits and characteristics of the traditional ACS. Besides, the proposed approach is easy to implement and could be applied in different kinds of problems in addition to mathematical problems. Several constrained functions are also evaluated to demonstrate the performance of the proposed algorithm.
Quality Scalability Compression on Single‐Loop Solution in HEVC
Authors: Zhang Mengmeng , Lu Hongyun , Liu Zhi
Published: June 2014

This paper proposes a quality scalable extension design for the upcoming high efficiency video coding (HEVC) standard. In the proposed design, the single‐loop decoder solution is extended into the proposed scalable scenario. A novel interlayer intra/interprediction is added to reduce the amount of bits representation by exploiting the correlation between coding layers. The experimental results indicate that the average Bjøntegaard delta rate decrease of 20.50% can be gained compared with the simulcast encoding. The proposed technique achieved 47.98% Bjøntegaard delta rate reduction compared with the scalable video coding extension of the H.264/AVC. Consequently, significant rate savings confirm that the proposed method achieves better performance.