bluuebunny/crossref_metadata_2025 huggingface dataset:
Endothelial dysfunction in gestational hypertension induced by catechol‐O‐methyltransferase inhibition
Authors: Hernandez M. , Hernandez I. , Rodriguez F. , Pertegal M. , Bonacasa B. , Salom M. G. , Quesada T. , Fenoy F. J.
Published: October 2012

New Findings

What is the central question of this study?

Gestational hypertension is a major obstetric problem of placental origin, associated with reduced production of 2‐methoxyestradiol. In this study, we evaluated in rats the consequences of pharmacological inhibition of catechol‐O‐methyltransferase, the enzyme that produces 2‐methoxyestradiol from 2‐hydroxyestradiol.

What is the main finding and its importance?

The present study provides evidence that inhibition of catechol‐O‐methyltransferase in pregnant rats produces arterial hypertension and endothelial dysfunction due to reduced nitric oxide bioavailability. The results help us to understand gestational hypertension and support a possible new approach to early diagnosis and treatment of the disease.

The present study evaluated whether catechol‐O‐methyltransferase inhibition in pregnant rats results in increased blood pressure and vascular endothelial dysfunction as a consequence of decreased nitric oxide bioavailability. Pregnant Sprague–Dawley rats were given entacapone (a catechol‐O‐methyltransferase inhibitor) by gavage from the 10th to the 20th day of pregnancy. Blood pressure was measured by plethysmography in the tail artery. Vascular endothelial function and NO release were assessed both in the absence and in the presence of tempol. Systolic blood pressure increased significantly in pregnant rats treated with entacapone compared with untreated pregnant rats on days 14 (143 ± 4 versus 122 ± 3 mmHg) and 19 of gestation (129 ± 4 versus 115 ± 5 mmHg). Both conductance (aortic rings) and resistance vessels (mesenteric small arterial vessels) from entacapone‐treated pregnant rats showed diminished relaxation in response to acetylcholine compared with vessels from vehicle‐treated pregnant and virgin rats. In mesenteric arterioles, this endothelial dysfunction was abolished in the presence of l‐NAME, indicating that it was caused by reduced NO availability, and it also improved in the presence of tempol, suggesting increased oxidative stress in hypertensive pregnant rats. Endothelial release of nitric oxide induced by calcium ionophore (A23187) was significantly greater in aortas from vehicle‐treated pregnant rats than in aortas from pregnant rats given entacapone. This endothelial dysfunction seen in hypertensive rats was prevented by addition of tempol. The present study provides evidence that catechol‐O‐methyltransferase inhibition in pregnant rats produces arterial hypertension and endothelial dysfunction due to reduced nitric oxide bioavailability.
Resonances of a Forced Mathieu Equation With Reference to Wind Turbine Blades
Authors: Ramakrishnan Venkatanarayanan , Feeny Brian F.
Published: October 2012

A horizontal axis wind turbine blade in steady rotation endures cyclic transverse loading due to wind shear, tower shadowing and gravity, and a cyclic gravitational axial loading at the same fundamental frequency. These direct and parametric excitations motivate the consideration of a forced Mathieu equation. This equation with cubic nonlinearity is analyzed for resonances by using the method of multiple scales. Superharmonic and subharmonic resonances occur. The effect of various parameters on the response of the system is demonstrated using the amplitude-frequency curve. The order-two superharmonic resonance persists for the linear system. While the order-two subharmonic response level is dependent on the ratio of parametric excitation and damping, nonlinearity is essential for the order-two subharmonic resonance. Order-three resonances are present in the system as well and, to first order, they are similar to those of the Duffing equation.
Coal Ash Deposition on Nozzle Guide Vanes—Part II: Computational Modeling
Authors: Barker B. , Casaday B. , Shankara P. , Ameri A. , Bons J. P.
Published: October 2012

Coal ash deposition was numerically modeled on a GE-E3 high pressure turbine vane passage. A model was developed, in conjunction with FLUENT™ software, to track individual particles through the turbine passage. Two sticking models were used to predict the rates of deposition which were subsequently compared to experimental trends. The strengths and limitations of the two sticking models, the critical viscosity model and the critical velocity model, are discussed. The former model ties deposition exclusively to particle temperature while the latter considers both the particle temperature and velocity. Both incorporate some level of empiricism, though the critical viscosity model has the potential to be more readily adaptable to different ash compositions. Experimental results show that both numerical models are reasonably accurate in predicting the initial stages of deposition. Beyond the initial stage of deposition, for which transient effects must be accounted.
Vibration Properties of High-Speed Planetary Gears With Gyroscopic Effects
Authors: Cooley Christopher G. , Parker Robert G.
Published: October 2012

This study investigates the modal property structure of high-speed planetary gears with gyroscopic effects. The vibration modes of these systems are complex-valued and speed-dependent. Equally-spaced and diametrically-opposed planet spacing are considered. Three mode types exist, and these are classified as planet, rotational, and translational modes. The properties of each mode type and that these three types are the only possible types are mathematically proven. Reduced eigenvalue problems are determined for each mode type. The eigenvalues for an example high-speed planetary gear are determined over a wide range of carrier speeds. Divergence and flutter instabilities are observed at extremely high speeds.
Rolling Bearing Localized Defect Evaluation by Multiscale Signature via Empirical Mode Decomposition
Authors: He Qingbo , Li Peng , Kong Fanrang
Published: October 2012

Measured vibration signals from rolling element bearings with defects are generally nonstationary, and are multiscale in nature owing to contributions from events with different localization in time and frequency. This paper presents a novel approach to characterize the multiscale signature via empirical mode decomposition (EMD) for rolling bearing localized defect evaluation. Vibration signal measured from a rolling element bearing is first adaptively decomposed by the EMD to achieve a series of usable intrinsic mode functions (IMFs) carrying the bearing health information at multiple scales. Then the localized defect-induced IMF is selected from all the IMFs based on a variance regression approach. The multiscale signature, called multiscale slope feature, is finally estimated from the regression line fitted over logarithmic variances of the IMFs excluding the defect IMF. The presented feature reveals the pattern of energy transfer among multiple scales due to localized defects, representing an inherent self-similar signature of the bearing health information that is embedded on multiple analyzed scales. Experimental results verify the performance of the proposed multiscale feature, and further discussions are provided.
Determining the Power Flow in a Rectangular Plate Using a Generalized Two-Step Regressive Discrete Fourier Series
Authors: Vuye Cedric , Guillaume Patrick , Vanlanduit Steve , Presezniak Flavio , Steenackers Gunther
Published: October 2012

The evaluation of structural power flow (or structural intensity (SI)) in engineering structures is a field of increasing interest in connection with vibration analysis and noise control. In contrast to classical techniques such as modal analysis, the SI indicates the magnitude and direction of the vibratory energy traveling in the structures, which yields information about the positions of the sources/sinks, along with the energy transmission path. In this paper, a new algorithm is proposed to model operational deflection shapes (ODS). The model is a two-dimensional Fourier domain model that is estimated by using a weighted nonlinear least-squares method. From the wave number-frequency domain data thus obtained, the spatial derivatives that are necessary to determine the structural power flow are easily computed. The proposed method is less sensitive to measurement noise than traditional power flow estimation techniques. A numerical model of a simply supported plate excited by two shakers, phased to act as an energy source and sink, is used as a simulation case. Measurements are executed on a clamped plate excited by an electromagnetic shaker in combination with a damper.
Surface/Interface Effect on Dynamic Stress Around a Nanoinclusion in a Semi-Infinite Slab Under Shear Waves
Authors: Fang Xue-Qian , Zhang Le-Le , Liu Jin-Xi , Feng Wen-Jie
Published: October 2012

This work examines the surface/interface effect on the dynamic stress around a cylindrical nanoinclusion embedded in an elastic semi-infinite slab subjected to antiplane shear waves, and the nanosize effect is considered. The wave function expansion method is employed to express the wave fields in the nanosized structure. The traction free boundary conditions at the three edges of this structure are considered and satisfied by using the image method. The analytical and numerical solutions of the dynamic stress concentration factor around the nanoinclusion are presented. Analyses show that the three edges of the nanosized structure manifest different effects of the dynamic stress around the nanoinclusion. The size effect is also related to the interface properties, the wave frequency of incident waves, and the material properties ratio of the nanoinclusion to matrix. To show the accuracy of the results for certain given parameters, comparison with the existing results is also given.
Approximate Entropy Analysis of the Acoustic Emission From Defects in Rolling Element Bearings
Authors: He Yongyong , Zhang Xinming
Published: October 2012

This paper introduces approximate entropy (ApEn) to address a nonlinear feature parameter of acoustic emission (AE) signal for the defect detection of rolling element bearings. With respect to AE signal, parameter selection of ApEn calculation is investigated, and appropriate parameters are suggested. Finally, an experimental study is presented to investigate the influence of various running conditions, i.e., radial load, rotating speed and defect size, on ApEn calculation. The results demonstrate that ApEn provides an effective measure for AE analysis and can be used as an effective feature parameter of AE signal for the defect detection of rolling element bearings.
Detection of Cracks in Mistuned Bladed Disks Using Reduced-Order Models and Vibration Data
Authors: Jung Chulwoo , Saito Akira , Epureanu Bogdan I.
Published: October 2012

A novel methodology to detect the presence of a crack and to predict the nonlinear forced response of mistuned turbine engine rotors with a cracked blade and mistuning is developed. The combined effects of the crack and mistuning are modeled. First, a hybrid-interface method based on component mode synthesis is employed to develop reduced-order models (ROMs) of the tuned system with a cracked blade. Constraint modes are added to model the displacements due to the intermittent contact between the crack surfaces. The degrees of freedom (DOFs) on the crack surfaces are retained as active DOFs so that the physical forces due to the contact/interaction (in the three-dimensional space) can be accurately modeled. Next, the presence of mistuning in the tuned system with a cracked blade is modeled. Component mode mistuning is used to account for mistuning present in the uncracked blades while the cracked blade is considered as a reference (with no mistuning). Next, the resulting (reduced-order) nonlinear equations of motion are solved by applying an alternating frequency/time-domain method. Using these efficient ROMs in a forced response analysis, it is found that the new modeling approach provides significant computational cost savings, while ensuring good accuracy relative to full-order finite element analyses. Furthermore, the effects of the cracked blade on the mistuned system are investigated and used to detect statistically the presence of a crack and to identify which blade of a full bladed disk is cracked. In particular, it is shown that cracks can be distinguished from mistuning.
MprAB Regulates theespAOperon in Mycobacterium tuberculosis and Modulates ESX-1 Function and Host Cytokine Response
Authors: Pang Xiuhua , Samten Buka , Cao Guangxiang , Wang Xisheng , Tvinnereim Amy R. , Chen Xiu-Lan , Howard Susan T.
Published: October 2012

The ESX-1 secretion system exports the immunomodulatory protein ESAT-6 and other proteins important in the pathogenesis ofMycobacterium tuberculosis. Components and substrates of ESX-1 are encoded at several loci, but the regulation of the encoding genes is only partially understood. In this study, we investigated the role of the MprAB two-component system in the regulation of ESX-1 activity. We determined that MprAB directly regulates theespAgene cluster, a locus necessary for ESX-1 function. Transcript mapping determined that the five genes in the cluster form an operon with two transcriptional start points, and several MprA binding sites were detected in theespApromoter. Expression analyses and promoter constructs indicated that MprAB represses theespAoperon. However, the MprAB mutant Rv-D981 secreted lower levels of EspA, ESAT-6, and the ESX-1 substrate EspB than control strains. Secretion of CFP10, which is normally cosecreted with ESAT-6, was similar in Rv-D981 and control strains, further demonstrating aberrant ESX-1 activity in the mutant. ESAT-6 induces proinflammatory cytokines, and macrophages infected with Rv-D981 elicited lower levels of interleukin 1β (IL-1β) and tumor necrosis factor alpha (TNF-α), consistent with the reduced levels of ESAT-6. These findings indicate that MprAB modulates ESX-1 function and reveal a new role for MprAB in host-pathogen interactions.
Solution Structure of Escherichia coli FeoA and Its Potential Role in Bacterial Ferrous Iron Transport
Authors: Lau Cheryl K. Y. , Ishida Hiroaki , Liu Zhihong , Vogel Hans J.
Published: October 2012

Iron is an indispensable nutrient for most organisms. Ferric iron (Fe
3+
) predominates under aerobic conditions, while during oxygen limitation ferrous (Fe
2+
) iron is usually present. The Feo system is a bacterial ferrous iron transport system first discovered in
Escherichia coli
K-12. It consists of three genes,
feoA
,
feoB
, and
feoC
(
yhgG
). FeoB is thought to be the main transmembrane transporter while FeoC is considered to be a transcriptional regulator. Using multidimensional nuclear magnetic resonance (NMR) spectroscopy, we have determined the solution structure of
E. coli
FeoA. The structure of FeoA reveals a Src-homology 3 (SH3)-like fold. The structure is composed of a β-barrel with two α-helices where one helix is positioned over the barrel. In comparison to the standard eukaryotic SH3 fold, FeoA has two additional α-helices. FeoA was further characterized by heteronuclear NMR dynamics measurements, which suggest that it is a monomeric, stable globular protein. Model-free analysis of the NMR relaxation results indicates that a slow conformational dynamic process is occurring in β-strand 4 that may be important for function.
31
P NMR-based GTPase activity measurements with the N-terminal domain of FeoB (NFeoB) indicate a higher GTP hydrolysis rate in the presence of potassium than with sodium. Further enzymatic assays with NFeoB suggest that FeoA may not act as a GTPase-activating protein as previously proposed. These findings, together with bioinformatics and structural analyses, suggest that FeoA may have a different role, possibly interacting with the cytoplasmic domain of the highly conserved core portion of the FeoB transmembrane region.
Antibacterial Activity of Alkyl Gallates against Xanthomonas citri subsp.
citri
Authors: Silva I. C. , Regasini L. O. , Petrônio M. S. , Silva D. H. S. , Bolzani V. S. , Belasque J. , Sacramento L. V. S. , Ferreira H.
Published: October 2012

The plant-pathogenic bacterium
Xanthomonas citri
subsp.
citri
is the causal agent of Asiatic citrus canker, a serious disease that affects all the cultivars of citrus in subtropical citrus-producing areas worldwide. There is no curative treatment for citrus canker; thus, the eradication of infected plants constitutes the only effective control of the spread of
X. citri
subsp.
citri
. Since the eradication program in the state of São Paulo, Brazil, is under threat, there is a clear risk of
X. citri
subsp.
citri
becoming endemic in the main orange-producing area in the world. Here we evaluated the potential use of alkyl gallates to prevent
X. citri
subsp.
citri
growth. These esters displayed a potent anti-
X. citri
subsp.
citri
activity similar to that of kanamycin (positive control), as evaluated by the resazurin microtiter assay (REMA). The treatment of
X. citri
subsp.
citri
cells with these compounds induced altered cell morphology, and investigations of the possible intracellular targets using
X. citri
subsp.
citri
strains labeled for the septum and centromere pointed to a common target involved in chromosome segregation and cell division. Finally, the artificial inoculation of citrus with
X. citri
subsp.
citri
cells pretreated with alkyl gallates showed that the bacterium loses the ability to colonize its host, which indicates the potential of these esters to protect citrus plants against
X. citri
subsp.
citri
infection.
Characterization of the Effects of an
rpoC
Mutation That Confers Resistance to the Fst Peptide Toxin-Antitoxin System Toxin
Authors: Brinkman Cassandra L. , Bumgarner Roger , Kittichotirat Weerayuth , Dunman Paul M. , Kuechenmeister Lisa J. , Weaver Keith E.
Published: October 2012

Overexpression of the Fst toxin in
Enterococcus faecalis
strain OG1X leads to defects in chromosome segregation, cell division and, eventually, membrane integrity. The M7 mutant derivative of OG1X is resistant to most of these effects but shows a slight growth defect in the absence of Fst. Full-genome sequencing revealed two differences between M7 and its OG1X parent. First, OG1X contains a frameshift mutation that inactivates the
etaR
response regulator gene, while M7 is a wild-type revertant for
etaR
. Second, the M7 mutant contains a missense mutation in the
rpoC
gene, which encodes the β′ subunit of RNA polymerase. Mutagenesis experiments revealed that the
rpoC
mutation was primarily responsible for the resistance phenotype. Microarray analysis revealed that a number of transporters were induced in OG1X when Fst was overexpressed. These transporters were not induced in M7 in response to Fst, and further experiments indicated that this had a direct protective effect on the mutant cells. Therefore, exposure of cells to Fst appears to have a cascading effect, first causing membrane stress and then potentiation of these effects by overexpression of certain transporters.
Glycopeptide Sulfation Evades Resistance
Authors: Kalan Lindsay , Perry Julie , Koteva Kalinka , Thaker Maulik , Wright Gerard
Published: October 2012

The incidence of antibiotic resistance among pathogenic microorganisms is increasing at an alarming rate. Resistance against front-line therapeutics such as the glycopeptide antibiotic vancomycin has emerged and has spread to highly virulent pathogens, including
Staphylococcus aureus
. Glycopeptide antibiotics are natural products from the
Actinomycetes
that have a characteristic heptapeptide core. The chemical diversity of the class is achieved through glycosylation, halogenation, methylation, and acylation of the core, modifications that are implicated in improved solubility, stability, or activity of the molecule. Sulfation is yet another modification observed infrequently in glycopeptides, but its role is not known. Although glycopeptide sulfotransferases are found in the environmental metagenome and must therefore serve an evolutionary purpose, all previous studies have reported decreased antibiotic activity with sulfation. We report that sulfation of glycopeptides has little effect on the compound's ability to bind its target, the
d
-Ala-
d
-Ala peptidoglycan precursors of the bacterial cell wall. However, sulfation does impact glycopeptide dimerization, and importantly, sulfated glycopeptides are significantly less potent inducers of the resistance gene cluster
vanHAX
in actinomycetes. Our results begin to unravel the mystery of the biological role of glycopeptide sulfation and offer a potential new strategy for the development of new antibiotics that avoid resistance.
Characterization of the Functional Domains of the SloR Metalloregulatory Protein in Streptococcus mutans
Authors: Haswell Jeffrey R. , Pruitt Benjamin W. , Cornacchione Louis P. , Coe Christopher L. , Smith Evan G. , Spatafora Grace A.
Published: October 2012

Streptococcus mutans
is a commensal member of the healthy plaque biofilm and the primary causative agent of dental caries. The present study is an investigation of SloR, a 25-kDa metalloregulatory protein that modulates genes responsible for
S. mutans
-induced cariogenesis. Previous studies of SloR homologues in other bacterial pathogens have identified three domains critical to repressor functionality: an N-terminal DNA-binding domain, a central dimerization domain, and a C-terminal FeoA (previously SH3-like) domain. We used site-directed mutagenesis to identify critical amino acid residues within each of these domains of the SloR protein. Select residues were targeted for mutagenesis, and nonconservative amino acid substitutions were introduced by overlap extension PCR. Furthermore, three C-terminally truncated SloR variants were generated using conventional PCR. The repressor functionality and DNA-binding ability of each variant was assessed using CAT reporter gene assays, real-time semiquantitative reverse transcriptase (qRT)-PCR, and electrophoretic mobility shift assays. We identified 12 residues within SloR that cause significant derepression of
sloABC
promoter activity (
P
< 0.05) compared to the results for wild-type SloR. Derepression was particularly noteworthy in metal ion-binding site 1 mutants, consistent with the site's importance in gene repression by SloR. In addition, a hyperactive SloR(E169A/Q170A) mutant was identified as having significantly heightened repression of
sloABC
promoter activity, and experiments with C-terminal deletion mutants support involvement of the FeoA domain in SloR-mediated gene repression. Given these results, we describe the functional domains of the
S. mutans
SloR protein and propose that the hyperactive mutant could serve as a target for rational drug design aimed at repressing SloR-mediated virulence gene expression.
Perthes’ disease of the hip: socioeconomic inequalities and the urban environment
Authors: Perry Daniel C , Bruce Colin E , Pope Daniel , Dangerfield Peter , Platt Mary Jane , Hall Andrew J
Published: October 2012

Introduction

Perthes’ disease is a puzzling childhood hip disorder for which the aetiology is unknown. It is known to be associated with socioeconomic deprivation. Urban environments have also been implicated as a risk factor, however socioeconomic deprivation often occurs within urban environments and it is unclear if this association is the result of confounding. The objective of the current work was to gain a greater understanding of the influence of the urban/rural environment in Perthes’ disease.

Methods

This was a descriptive observational study using the Scottish Morbidity Record, based in Scotland, UK using data from 2000–2010. A total of 443 patients with a discharge diagnosis of Perthes’ disease were included. Socioeconomic deprivation was determined using the Scottish Index of Multiple Deprivation, and exposure to the ‘urban environment’ was recorded based on the Scottish Urban–Rural Classification.

Results

There was a strong association with socioeconomic deprivation, with rates among the most deprived quintile more than twice those of the most affluent (RR 2.1 (95% CI 1.5 to 2.9)). Urban areas had a greater rate of Perthes’ disease discharges (RR 1.8 (95% CI 1.1 to 3.2)), though this was a reflection of greater deprivation in urban areas. Stratification for socioeconomic deprivation revealed similar discharge rates in urban and rural environments, suggesting that the aetiological determinants were not independently associated with urban environments.

Conclusions

The occurrence of Perthes’ disease within urban environments is high, yet this appears to be a reflection of higher socioeconomic deprivation exposure. Disease rates appear equivalent in similarly deprived urban and non-urban areas, suggesting that the determinant is not a consequence of the urban environment.
Adnexal torsion in third trimester of pregnancy
Authors: Passarinho Rita Marquez , Afonso Énio , Reis Luís , Santos Silva Isabel
Published: October 2012

The authors report an unusual case of adnexal torsion in a patient in the third trimester of pregnancy. A 32-year-old woman, gravida 1, para 0, in the 32nd week of gestation initially presented with clinical signs of acute appendicitis. On laparotomy, it was identified that a necrotic mass of the right adnexa and performed a unilateral salpingo-oophorectomy. The postoperative period was uneventful. In the 37th week of gestation, the labour was induced by fetal intrauterine growth restriction. She delivered vaginally, a healthy baby, with 2085 g and an Apgar score of 9 and 10 at the first and fifth minute, respectively.
Painful ophthalmoplegia with simultaneous orbital myositis, optic and oculomotor nerve inflammation and trigeminal nucleus involvement in a patient with herpes zoster ophthalmicus
Authors: Paraskevas Georgios P , Anagnostou Evangelos , Vassilopoulou Sofia , Spengos Konstantinos
Published: October 2012

Viral infection is a rare cause of painful ophthalmoplegia. We report on a 67-year-old patient who developed painful double vision after a vesicular skin rash on the left forehead. MRI disclosed simultaneous inflammatory lesions in all extraocular muscles, the second and third cranial nerve, as well as pathological signal intensity along the spinal trigeminal tract and nucleus within the medulla oblongata and the pons. Cerebrospinal fluid and serum tests for varicella zoster were positive. The patient was treated effectively with intravenous acyclovir and methylprednisolone. Simultaneous lesions in various neighbouring neural structures may be characteristic for the highly neurotropic behaviour of the herpesviridae and should be considered as a cause of painful ophthalmoplegia that can be depicted by appropriate imaging.
Adverse events related to intravenous antibiotic therapy: a prospective observational study in the treatment of infective endocarditis
Authors: De Paula Débora Holanda Gonçalves , Tura Bernardo Rangel , Lamas Cristiane da Cruz
Published: October 2012

Objective

The goal of this prospective observational study was to identify adverse events (AEs) related to the use of intravenous access sites used for infective endocarditis (IE) treatment in a tertiary care hospital.

Design

This is an observational, analytical and prospective study on AEs resulting from the use of intravenous access sites in patients under antimicrobial treatment for IE. Patients enrolled in the International Collaboration on Endocarditis (ICE) study had their peripheral, short-term central catheters (CVC) and peripherally inserted central catheters (PICC) monitored for AEs.

Setting

Tertiary care hospital for cardiac surgery in Rio de Janeiro, Brazil.

Patients

Patients over 14 years of age, hospitalised in 2009 and 2010 with possible or definite criteria for IE by the modified Duke criteria were included.

Main outcome measures

AEs related to intravenous catheters: erythema and infiltration, fever, obstruction, externalisation and blood stream infection.

Results

Thirty-seven episodes of IE in 35 patients were studied. Mean patient age was 44.32±15.2 years; 22 (63%) were men. The number of vascular catheters studied were 253, 148 of which were peripheral, 85 CVC (21 of which for haemodialysis) and 20 PICC. The most frequent AEs were ‘erythema’ and ‘infiltration’ for peripheral catheters, ‘fever’ for CVCs and ‘obstruction’ and ‘externalisation’ for PICCs. The number of catheter-days was 360 for peripheral catheters, 1.156 for CVC and 420 for PICC. Kaplan-Meier curves for CVC and PICC showed statistical difference for obstruction (p<0.001) in PICCs. More bacteraemia occurred in CVC compared with PICC.

Conclusions

The choice of intravenous access sites is critical in the treatment of IE. Close observation for AEs and stricter implementation of infection control measures and better manipulation of catheters are suggested.
Hydromechanical behaviour of a silty sand from a steep slope triggered by artificial rainfall: from unsaturated to saturated conditions
Authors: Casini Francesca , Serri Victor , Springman Sarah M.
Published: October 2012

This paper presents an experimental investigation aimed at studying the hydromechanical behaviour of a silty sand from a steep slope in Ruedlingen in the northeast of Switzerland, where a landslide-triggering experiment was carried out. The hydromechanical behaviour of the statically compacted Ruedlingen silty sand has been studied under saturated and unsaturated conditions, beginning with different initial void ratios and water contents. The specimens were prepared in the laboratory using static compaction, to reproduce the mean dry density and mean water content expected in natural unsaturated in situ conditions, thus promoting specimen homogeneity and test repeatability. The choice of compaction parameters was supported by a detailed physical and microstructural investigation to produce laboratory specimens with a similar microstructure to that of the natural soil. The aim of the work was to characterize the mechanical behaviour of the soil at different gravimetric water contents in a triaxial stress path apparatus and to link the mechanical behaviour with the soil-water retention curve obtained under suction-controlled conditions with different void ratios. Soil specimens with three different gravimetric water contents were exposed to conventional isotropically consolidated drained and undrained stress paths for the water phase and to stress paths simulating in situ anisotropic compression followed by a decrease of mean effective stress at constant axial load. The radial deformation of the unsaturated specimens was measured with a laser device installed in a triaxial stress path cell. Results have been interpreted using a Bishop stress approach, evaluating the suction through the water retention curve. A simple equation has been proposed to model the compressibility behaviour of the soil tested, which depends on the parameter χ and the stress ratio η. Possible unstable response along the stress path analysed has been investigated by means of second-order work and the validity of a unified framework has also been verified under unsaturated conditions.
EFFICIENT DATA STRUCTURE FOR REPRESENTING AND SIMPLIFYING SIMPLICIAL COMPLEXES IN HIGH DIMENSIONS
Authors: ATTALI DOMINIQUE , LIEUTIER ANDRÉ , SALINAS DAVID
Published: October 2012

We study the simplification of simplicial complexes by repeated edge contractions. First, we extend to arbitrary simplicial complexes the statement that edges satisfying the link condition can be contracted while preserving the homotopy type. Our primary interest is to simplify flag complexes such as Rips complexes for which it was proved recently that they can provide topologically correct reconstructions of shapes. Flag complexes (sometimes called clique complexes) enjoy the nice property of being completely determined by the graph of their edges. But, as we simplify a flag complex by repeated edge contractions, the property that it is a flag complex is likely to be lost. Our second contribution is to propose a new representation for simplicial complexes particularly well adapted for complexes close to flag complexes. The idea is to encode a simplicial complex K by the graph G of its edges together with the inclusion-minimal simplices in the set difference Flag (G)\ K. We call these minimal simplices blockers. We prove that the link condition translates nicely in terms of blockers and give formulae for updating our data structure after an edge contraction. Finally, we observe in some simple cases that few blockers appear during the simplification of Rips complexes, demonstrating the efficiency of our representation in this context.
INHIBITION EFFECT OF DODECYLAMINE ON CARBON STEEL CORROSION IN HYDROCHLORIC ACID SOLUTION
Authors: CHEN ZHENYU , HUANG LING , QIU YUBING , GUO XINGPENG
Published: October 2012

Dodecylamine spontaneously adsorbs on carbon steel via its polar group (-NH2) in hydrochloric acid solution. Furthermore, it forms a monolayer film on carbon steel surface. The inhibition mechanism of dodecylamine for carbon steel is geometric blocking effect. The adsorption of dodecylamine on carbon steel surface follows Arrhenius equation. The adsorption slightly increases activated energy, but greatly reduces pre-exponential factor value. Atomic force microscopy force curves indicate that at the area without adsorbed dodecylamine, no obvious adhere force occurs. At the area with adsorbed dodecylamine, however, an average 1.3 nN adhere force is observed.
ELECTROLESS DEPOSITION OF NICKEL ON LEAD ZIRCONIUM TITANATE CERAMICS: PREPARATION, MAGNETIC AND MAGNETOELECTRIC PROPERTIES
Authors: BI K. , HONG H. , WU W. , WANG Y. G.
Published: October 2012

The Ni layers with good soft magnetic properties have been successfully electroless deposited on PZT layers. To study the thermodynamics and kinetics of electroless Ni -deposition, the effect of bath parameters such as pH and temperature has been discussed. The structural, magnetic and magnetostrictive properties of Ni layers deposited at various pH and temperature are characterized by X-ray diffraction, transmission electron microscopy, vibrating sample magnetometer and standard strain-gauge technique. The grain size, deposition rate, magnetic properties and magnetostrictive properties of Ni layers and magnetoelectric effect of Ni /PZT/ Ni trilayers depend strongly on the thermodynamics and kinetics of electroless deposition processes. A maximum ME voltage coefficient of αE,31 = 5.8 V cm-1 Oe-1 is obtained at a frequency of about 101 kHz. These trilayers exhibit a promising potential in actuators, transducers and sensors.
PREDICATION FOR RELATIVE MOTION OF THE COLONOSCOPE IN COLONOSCOPY
Authors: CHENG WU BIN , MOSER MICHAEL A. J. , KANAGARATNAM SIVARUBAN , ZHANG WEN JUN
Published: October 2012

Colonoscopy is common procedure frequently carried out. It is not without its problems, which include looping formation. Looping formation prevents the tip of the colonoscope itself from advancing, thus further probing induces a risk of perforation, significant patient discomfort, and failure of colonoscopy. During colonoscopy, the manipulated colonoscope for intubation in the colon goes through the friction between the colonoscope and the colon. Due to major frictional force, the sigmoidal colon forms looping with the scope during intubation. The interactive frictional force between the colon and the colonoscope is highly complex because of frictional contact between two deformable objects. In this paper, contact force computation was formulated into a linear complementarity problem (LCP) by linearizing Signorini's problem, which was adapted into non-interpenetration with unilateral constraints. Frictional force was computed by the mechanical compliance of finite element method (FEM) models with the consideration of dynamic friction between the colonoscope and the intestinal wall. Furthermore, we presented a mathematical model of the elongation of the colon that predicts the motion of scope relative to the intestinal wall in colonoscopy.
EVERY LONGEST HAMILTONIAN PATH IN EVEN n-GONS
Authors: NIEL BLANCA I.
Published: October 2012

We single out every longest path of n-1 order that solves each of the [Formula: see text] Longest Euclidean Hamiltonian Path Problems on the even nth root of the unity, by means of a geometric and arithmetic procedure. This identification is done regardless of planar rotations and orientation. In addition, the uniqueness of the Euclidean Hamiltonian cycle that resolves the Maximum Traveling Salesman Problem is shown.
Association Between Smoke-Free Legislation and Hospitalizations for Cardiac, Cerebrovascular, and Respiratory Diseases
Authors: Tan Crystal E. , Glantz Stanton A.
Published: October 2012

Background—

Secondhand smoke causes cardiovascular and respiratory disease. Smoke-free legislation is associated with a lower risk of hospitalization and death from these diseases.

Methods and Results—

Random-effects meta-analysis was conducted by law comprehensiveness to determine the relationship between smoke-free legislation and hospital admission or death from cardiac, cerebrovascular, and respiratory diseases. Studies were identified by using a systematic search for studies published before November 30, 2011 with the use of the Science Citation Index, Google Scholar, PubMed, and Embase and references in identified articles. Change in hospital admissions (or deaths) in the presence of a smoke-free law, duration of follow-up, and law comprehensiveness (workplaces only; workplaces and restaurants; or workplaces, restaurants, and bars) were recorded. Forty-five studies of 33 smoke-free laws with median follow-up of 24 months (range, 2–57 months) were included. Comprehensive smoke-free legislation was associated with significantly lower rates of hospital admissions (or deaths) for all 4 diagnostic groups: coronary events (relative risk, 0.848; 95% confidence interval 0.816–0.881), other heart disease (relative risk, 0.610; 95% confidence interval, 0.440–0.847), cerebrovascular accidents (relative risk, 0.840; 95% confidence interval, 0.753–0.936), and respiratory disease (relative risk, 0.760; 95% confidence interval, 0.682–0.846). The difference in risk following comprehensive smoke-free laws does not change with longer follow-up. More comprehensive laws were associated with larger changes in risk.

Conclusions—

Smoke-free legislation was associated with a lower risk of smoking-related cardiac, cerebrovascular, and respiratory diseases, with more comprehensive laws associated with greater changes in risk.
A Comparison of CMIP3 Simulations of Precipitation over North America with Observations: Daily Statistics and Circulation Features Accompanying Extreme Events
Authors: DeAngelis Anthony M. , Broccoli Anthony J. , Decker Steven G.
Published: October 2012

Climate model simulations of daily precipitation statistics from the third phase of the Coupled Model Intercomparison Project (CMIP3) were evaluated against precipitation observations from North America over the period 1979–99. The evaluation revealed that the models underestimate the intensity of heavy and extreme precipitation along the Pacific coast, southeastern United States, and southern Mexico, and these biases are robust among the models. The models also overestimate the intensity of light precipitation events over much of North America, resulting in fairly realistic mean precipitation in many places. In contrast, heavy precipitation is simulated realistically over northern and eastern Canada, as is the seasonal cycle of heavy precipitation over a majority of North America. An evaluation of the simulated atmospheric dynamics and thermodynamics associated with extreme precipitation events was also conducted using the North American Regional Reanalysis (NARR). The models were found to capture the large-scale physical mechanisms that generate extreme precipitation realistically, although they tend to overestimate the strength of the associated atmospheric circulation features. This suggests that climate model deficiencies such as insufficient spatial resolution, inadequate representation of convective precipitation, and overly smoothed topography may be more important for biases in simulated heavy precipitation than errors in the large-scale circulation during extreme events.
Remote Forcing versus Local Feedback of East Pacific Intraseasonal Variability during Boreal Summer
Authors: Rydbeck Adam V. , Maloney Eric D. , Xie Shang-Ping , Hafner Jan , Shaman Jeffrey
Published: October 2012

During boreal summer (June–October), interactions between intraseasonal variability in the Eastern Hemisphere and east Pacific warm pool are often described as a local amplification of the Madden–Julian oscillation (MJO), the dominant mode of tropical intraseasonal variability. The MJO in the Eastern Hemisphere emits eastward-propagating dry Kelvin waves that are a source of rapid communication with the east Pacific. However, the precise mechanism by and degree to which intraseasonal variability in the Eastern Hemisphere interacts with the east Pacific are not well understood. To quantify the relationship, sensitivity tests in two separate models are used: the National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM) and the International Pacific Research Center Regional Atmosphere Model (IRAM). Different methods are employed to isolate the east Pacific from outside intraseasonal signals in each model. When isolated from Kelvin wave fronts associated with the MJO, the CAM produces similar east Pacific intraseasonal variability to observations. In the CAM, the communication of intraseasonal signals by Kelvin waves does not appear necessary to the initiation and maintenance of east Pacific intraseasonal variability, suggesting that such events can be independent of the MJO. However, communication by MJO-initiated Kelvin waves provides a possible phase locking mechanism between hemispheres. When the east Pacific is isolated from all remote intraseasonal signals in the IRAM, intraseasonal events there are weak and incoherent. In the IRAM communication across the Pacific appears necessary to the representation of east Pacific intraseasonal variability. However, the IRAM contains an important bias in the climatological low-level winds that may suppress east Pacific intraseasonal events.
Estimate of Ocean Mixed Layer Deepening after a Typhoon Passage over the South China Sea by Using Satellite Data
Authors: Pan Jiayi , Sun Yujuan
Published: October 2012

The ocean responses to Typhoon Cimaron, which influenced the South China Sea (SCS) from 1 to 8 November 2006, are analyzed. Based on satellite-observed sea surface temperature (SST) and climatological temperature profiles in the SCS, mixed layer deepening, an important parameter characterizing turbulent mixing and upwelling driven by strong typhoon winds, is derived. Corresponding to the SST drop of 4.4°C on 3 November 2006, the mixed layer deepened by 104.5 m relative to the undisturbed depth of 43.2 m, which is consistent with a simulation result from a mixed layer model. Furthermore, baroclinic geostrophic velocity and vorticity are calculated from the surface temperature gradient caused by the typhoon. The negative vorticity, associated with the typhoon cooling, indicated an anticyclonic baroclinic circulation strongest at the base of the mixed layer and at the depth of 50 m, the geostrophic speed reached as high as 0.2 m s−1. Typhoon Cimaron proceeded slowly (1.7 m s−1) when it was making a southwestward turn on 3 November 2006, resulting in a subcritical condition with a Froude number (the ratio of typhoon translation speed to first baroclinic mode speed) of 0.6 around the maximum SST drop location and facilitating high SST cooling and mixed layer deepening because of the absence of inertial-gravity waves in the wake of the typhoon. Comparison of Argo buoy data with the climatological temperature suggests that the average uncertainty in the mixed layer deepening estimation caused by the difference between Argo and climatological temperature profiles is less than 10 m.
Influence of Bottom Topography on Integral Constraints in Zonal Flows with Parameterized Potential Vorticity Fluxes
Authors: Ivchenko V. O. , Sinha B. , Zalesny V. B. , Marsh R. , Blaker A. T.
Published: October 2012

An integral constraint for eddy fluxes of potential vorticity (PV), corresponding to global momentum conservation, is applied to two-layer zonal quasigeostrophic channel flow. This constraint must be satisfied for any type of parameterization of eddy PV fluxes. Bottom topography strongly influences the integral constraint compared to a flat bottom channel. An analytical solution for the mean flow solution has been found by using asymptotic expansion in a small parameter, which is the ratio of the Rossby radius to the meridional extent of the channel. Applying the integral constraint to this solution, one can find restrictions for eddy PV transfer coefficients that relate the eddy fluxes of PV to the mean flow. These restrictions strongly deviate from restrictions for the channel with flat bottom topography.
A Note on the Role of Mean Flows in Doppler-Shifted Frequencies
Authors: Gerkema Theo , Maas Leo R. M. , van Haren Hans
Published: October 2012

The purpose of this paper is to resolve a confusion that may arise from two quite distinct definitions of “Doppler shifts”: both are used in the oceanographic literature but they are sometimes conflated. One refers to the difference in frequencies measured by two observers, one at a fixed position and one moving with the mean flow—here referred to as “quasi-Doppler shifts.” The other definition is the one used in physics, where the frequency measured by an observer is compared to that of the source. In the latter sense, Doppler shifts occur only if the source and observer move with respect to each other; a steady mean flow alone cannot create a Doppler shift. This paper rehashes the classical theory to straighten out some misconceptions. It is also discussed how wave dispersion affects the classical relations and their application.
Three-Dimensional VHF Lightning Mapping System for Winter Thunderstorms
Authors: Nishihashi Masahide , Shimose Ken-ichi , Kusunoki Kenichi , Hayashi Syugo , Arai Ken-ichiro , Inoue Hanako Y. , Mashiko Wataru , Kusume Masako , Morishima Hiroyuki
Published: October 2012

A three-dimensional (3D) winter lightning mapping system employing very high frequency (VHF) broadband signals was developed for continuous remote observation in winter. VHF broadband pulses radiated by leader progression are received with three discone antennas arranged in a triangle (20–30 m) and recorded on a high-speed digital oscilloscope (1.25-GHz sampling) with GPS digital timing data. The two-dimensional (2D) mapping for azimuth and elevation of the VHF radiation sources was conducted by computing the arrival time differences of three pulses using a cross-correlation technique. From azimuth and elevation data from two sites extracted within a given time frame, 3D lightning mapping was performed using the triangulation scheme. An observation network for winter lightning was constructed within a comprehensive meteorological observation network in the Shonai area, which is located on the coast of the Japan Sea. This report includes the preliminary 2D and 3D mapping of winter lightning observed on 3 December 2010. The horizontal and vertical distributions of VHF radiation sources were consistent with the radar echo observed with X-band Doppler radar. These results indicate that the system can detect winter lightning discharges and perform 2D and 3D lightning mapping in detail.