bluuebunny/crossref_metadata_2025 huggingface dataset:
Standard Measurement of Aircraft Gas Turbine Engine Exhaust Smoke
Authors: Champagne D. L.
Published: April 2015

A standard system (equipment and procedures) for measuring smoke emitted by aircraft turbine engines has been developed. It has been adopted by several Federal Government agencies. In this paper, the system is explained and its accuracy defined. An experimentally determined relationship between the system’s parameters and true smoke density (weight of solids per unit volume) is presented and theoretically examined. The definition of smoke plume visibility in terms of the system’s parameters is also developed. This work led to the conclusion that aircraft turbine engine exhaust smoke is composed of two groups of particles: the very small, which are primarily responsible for visible obscuration, and larger particles, which may constitute as much as half of the total by weight, but do not appreciably contribute to plume visibility.
The Computation of Transonic Flow Through Two-Dimensional Gas Turbine Cascades
Authors: McDonald P. W.
Published: April 2015

Steady transonic flow through two-dimensional gas turbine cascades is efficiently predicted using a time-dependent formulation of the equations of motion. An integral representation of the equations has been used in which subsonic and supersonic regions of the flow field receive identical treatment. Mild shock structures are permitted to develop naturally without prior knowledge of their exact strength or position. Although the solutions yield a complete definition of the flow field, the primary aim is to produce airfoil surface pressure distributions for the design of aerodynamically efficient turbine blade contours. In order to demonstrate the accuracy of this method, computed airfoil pressure distributions have been compared to experimental results.
Development of Borsic®-Aluminum Composite Fan Blades for Supersonic Turbofan Engines
Authors: Schulz W. J. , Mangiapane J. A. , Stargardter H.
Published: April 2015

The development of BORSIC®-Aluminum fan blades for elevated temperature application in gas-turbine power plants has been successfully demonstrated. These fan blades are over 40 percent lighter than the titanium blades currently in use. In addition, the high modulus of the reinforcement allows fan blades to be designed without partspan shrouds which will result in a 1 percent increase in fan efficiency. A full set of blades (36) fabricated by diffusion bonding were assembled in a rotor and tested in an aeromechanical rig with both a clean inlet and a distortion inlet at ambient inlet temperature as well as with a heated inlet to produce a blade temperature of 430 F. Total running time was 30.3 hrs, eight of which were at or above design speed. The rig ran for 0.5 hrs at design speed with a blade temperature of 430 F. No severe vibratory stresses were encountered with either a clean inlet or a 2E distortion screen.
Ray-based description of mode coupling by sound speed fluctuations in the ocean
Authors: Virovlyansky A. L.
Published: April 2015

A traditional approach to the analysis of mode coupling in a fluctuating underwater waveguide is based on solving the system of coupled equations for the second statistical moments of mode amplitudes derived in the Markov approximation [D. B. Creamer, J. Acoust. Soc. Am. 99, 2825–2838 (1996)]. In the present work, an alternative approach is considered. It is based on an analytic solution of the mode coupling equation derived in the high frequency approximation [A. L. Virovlyanskii and A. G. Kosterin, Sov. Phys. Acoust. 35, 138–142 (1987)]. This solution, representing the mode amplitude as a sum of contributions from two geometrical rays, is convenient for statistical averaging. It allows one to easily derive analytical expressions for any statistical moments of mode amplitudes. The applicability of this approach is demonstrated by comparing its predictions for a deep water acoustic waveguide with results of a full wave numerical simulation carried out using the method of wide angle parabolic equation.
Automatic identification of multiply diffracted waves and their ordered scattering paths
Authors: Löer Katrin , Meles Giovanni A. , Curtis Andrew
Published: April 2015

An automated algorithm uses recordings of acoustic energy across a spatially-distributed array to derive information about multiply scattered acoustic waves in heterogeneous media. The arrival time and scattering-order of each recorded diffracted acoustic wave, and the exact sequence of diffractors encountered by that wave, are estimated without requiring an explicit model of the medium through which the wave propagated. Individual diffractors are identified on the basis of their unique single-scattering relative travel-time curves (move-outs) across the array, and secondary (twice-scattered) waves are detected using semblance analysis along temporally offset primary move-outs. This information is sufficient to estimate travel times and scattering paths of all multiply diffracted waves of any order, and for these events to be identified in recorded data. The algorithm is applied to synthetic acoustic data sets from a variety of media, including different numbers of point-diffractors and a medium with strong heterogeneity and non-hyperbolic move-outs.
Effects of wide dynamic-range compression on the perceived clarity of individual musical instruments
Authors: Madsen Sara M. K. , Stone Michael A. , McKinney Martin F. , Fitz Kelly , Moore Brian C. J.
Published: April 2015

The effects of wide-dynamic-range compression (WDRC) on the ability of hearing-impaired subjects to hear out individual instruments or voices (called “sources”) in a mixture were explored. On each trial, the subjects were asked to judge the relative clarity of the target in two repetitions of the same music excerpt (mixture of sources) that were processed in different ways. The stimuli were processed via a five-channel simulated WDRC hearing aid, using individual insertion gains and compression ratios recommended by the CAM2 fitting procedure. Both fast- and slow-acting WDRC and a condition with linear amplification and frequency-response shaping were used. To investigate the role of cross-modulation (the partial correlation of the envelopes of different sources caused by the time-varying gain applied by the compressor), conditions were included where the sounds from different sources were compressed before being added together and where the sounds were added together before being compressed. The results showed no effect of cross-modulation, lower clarity with WDRC than with linear amplification, and no significant overall effect of compression speed, although some subjects consistently rated clarity as greater with slow compression. The deleterious effect of WDRC may be related to changes in temporal-envelope shape or reduced spectral contrast produced by WDRC.
Identification of high-pass filtered male, female, and child vowels: The use of high-frequency cues
Authors: Donai Jeremy J. , Paschall D. Dwayne
Published: April 2015

Vowels are characteristically described according to low-frequency resonance characteristics, which are presumed to provide the requisite information for identification. Classically, the study of vowel perception has focused on the lowest formant frequencies, typically F1, F2, and F3. Lehiste and Peterson [Phonetica 4, 161–177 (1959)] investigated identification accuracy of naturally produced male vowels composed of various amounts of low- and high-frequency content. Results showed near-chance identification performance for vowel segments containing only spectral information above 3.5 kHz. The authors concluded that high-frequency information was of minor importance for vowel identification. The current experiments report identification accuracy for high-pass filtered vowels produced by two male, two female, and two child talkers using both between- and within-subject designs. Identification performance was found to be significantly above chance for the majority of vowels even after high-pass filtering to remove spectral content below 3.0–3.5 kHz. Additionally, the filtered vowels having the highest fundamental frequency (child talkers) often had the highest identification accuracy scores. Linear discriminant function analysis mirrored perceptual performance when using spectral peak information between 3 and 12 kHz.
Oscillation regimes produced by an alto saxophone: Influence of the control parameters and the bore inharmonicity
Authors: Doc Jean-Baptiste , Vergez Christophe
Published: April 2015

The aim of this work is to highlight experimentally how inharmonicity of the bore resonance frequencies of an alto saxophone influences the nature of the oscillation regimes. A variable volume branching from the neck of an alto sax at an appropriate position allows one to change the frequency of the first resonance independently from the second. A blowing machine with artificial lips is used to make the saxophone play while controlling independently the control parameters: the blowing pressure and an embouchure parameter. Values of these parameters are estimated experimentally through the measurement of the nonlinear characteristics linking the mean air flow blown into the instrument to the static pressure difference across the reed. Experiments with different values of the control parameters as well as of the inharmonicity produce different kinds of oscillation regimes. These regimes are categorized through the analysis of the pressure signal inside the mouthpiece. The resulting maps demonstrate that the emergence of quasi-periodic regimes, and their extent, depend on the level of inharmonicity, but also on the values of the control parameters. Periodic regimes playable by choosing appropriate values of the control parameters also differ according to the level of inharmonicity, a higher inharmonicity facilitating the emergence of the third register.
Fuzzy information transmission analysis for continuous speech features
Authors: Oosthuizen Dirk J. J. , Hanekom Johan J.
Published: April 2015

Feature information transmission analysis (FITA) estimates information transmitted by an acoustic feature by assigning tokens to categories according to the feature under investigation and comparing within-category to between-category confusions. FITA was initially developed for categorical features (e.g., voicing) for which the category assignments arise from the feature definition. When used with continuous features (e.g., formants), it may happen that pairs of tokens in different categories are more similar than pairs of tokens in the same category. The estimated transmitted information may be sensitive to category boundary location and the selected number of categories. This paper proposes a fuzzy approach to FITA that provides a smoother transition between categories and compares its sensitivity to grouping parameters with that of the traditional approach. The fuzzy FITA was found to be sufficiently robust to boundary location to allow automation of category boundary selection. Traditional and fuzzy FITA were found to be sensitive to the number of categories. This is inherent to the mechanism of isolating a feature by dividing tokens into categories, so that transmitted information values calculated using different numbers of categories should not be compared. Four categories are recommended for continuous features when twelve tokens are used.
Gender typicality in children's speech: A comparison of boys with and without gender identity disorder
Authors: Munson Benjamin , Crocker Laura , Pierrehumbert Janet B. , Owen-Anderson Allison , Zucker Kenneth J.
Published: April 2015

This study examined whether boys with gender identity disorder (GID) produced less prototypically male speech than control boys without GID, a possibility that has been suggested by clinical observations. Two groups of listeners participated in tasks where they rated the gender typicality of single words (group 1) or sentences (group 2) produced by 15 5–13 year old boys with GID and 15 age-matched boys without GID. Detailed acoustic analyses of the stimuli were also conducted. Boys with GID were rated as less boy-like than boys without GID. In the experiment using sentence stimuli, these group differences were larger than in the experiment using single-word stimuli. Listeners' ratings were predicted by a variety of acoustic parameters, including ones that differ between the two groups and ones that are stereotypically associated with adult men's and women's speech. Future research should examine how these variants are acquired.
Structure in time-frequency binary masking errors and its impact on speech intelligibility
Authors: Kressner Abigail A. , Rozell Christopher J.
Published: April 2015

Although requiring prior knowledge makes the ideal binary mask an impractical algorithm, substantial increases in measured intelligibility make it a desirable benchmark. While this benchmark has been studied extensively, many questions remain about the factors that influence the intelligibility of binary-masked speech with non-ideal masks. To date, researchers have used primarily uniformly random, uncorrelated mask errors and independently presented error types (i.e., false positives and negatives) to characterize the influence of estimation errors on intelligibility. However, practical estimation algorithms produce masks that contain errors of both types and with non-trivial amounts of structure. This paper introduces an investigation framework for binary masks and presents listener studies that use this framework to illustrate how interactions between error types and structure affect intelligibility. First, this study demonstrates that clustering (i.e., a form of structure) of mask errors reduces intelligibility. Furthermore, while previous research has suggested that false positives are more detrimental to intelligibility than false negatives, this study indicates that false negatives can be equally detrimental to intelligibility when they contain structure or when both error types are present. Finally, this study shows that listeners tolerate fewer mask errors when both types of errors are present, especially when the errors contain structure.
Exact solution for a photoacoustic wave from a finite-length cylindrical source
Authors: Zalev Jason , Kolios Michael C.
Published: April 2015

In wide-field pulsed photoacoustics, a nearly instantaneous source of electromagnetic energy is applied uniformly to an absorbing medium to create an acoustic wave. In this work, an exact solution is derived for the photoacoustic wave originating from a finite-length solid cylindrical source in terms of known analytic functions involving elliptic integrals of canonical form. The solution is compared with the output of a finite-element simulation.
Fast characterization of two ultrasound longitudinal waves in cancellous bone using an adaptive beamforming technique
Authors: Taki Hirofumi , Nagatani Yoshiki , Matsukawa Mami , Mizuno Katsunori , Sato Toru
Published: April 2015

The received signal in through-transmission ultrasound measurements of cancellous bone consists of two longitudinal waves, called the fast and slow waves. Analysis of these fast and slow waves may reveal characteristics of the cancellous bone that would be good indicators of osteoporosis. Because the two waves often overlap, decomposition of the received signal is an important problem in the characterization of bone quality. This study proposes a fast and accurate decomposition method based on the frequency domain interferometry imaging method with a modified wave transfer function that uses a phase rotation parameter. The proposed method accurately characterized the fast and slow waves in the experimental study, and the residual intensity, which was normalized with respect to the received signal intensity, was less than −20 dB over the bone specimen thickness range from 6 to 15 mm. In the simulation study, the residual intensity was less than −20 dB over the specimen thickness range from 3 to 8 mm. Decomposition of a single received signal takes only 5 s using a laptop personal computer with a single central processing unit. The proposed method has great potential to provide accurate and rapid measurements of indicators of osteoporosis in cancellous bone.
A unified approach to an augmented Burgers equation for the propagation of sonic booms
Authors: Yamamoto Masafumi , Hashimoto Atsushi , Aoyama Takashi , Sakai Takeharu
Published: April 2015

Nonlinear propagation through a relaxing atmosphere of pressure disturbances extracted from a computational fluid dynamics (CFD) solution of the flow around a supersonic aircraft is simulated using an augmented Burgers equation. The effects of nonlinearity, geometrical spreading, atmospheric inhomogeneity, thermoviscous attenuation, and molecular vibration relaxation are taken into account. The augmented Burgers equation used for sonic boom propagation calculations is often solved by the operator splitting method, but numerical difficulties arise with this approach when dissipation is not effective. By re-examining the solution algorithms for the augmented Burgers equation, a stable method for handling the relaxation effect has been developed. This approach can handle the Burgers equation in a unified manner without operator splitting and, therefore, the resulting scheme is twice as fast as the original one. The approach is validated by comparing it with an analytical solution and a detailed CFD of dispersed plane wave propagation. In addition, a rise time prediction of low-boom supersonic aircraft is demonstrated.
Temporal proteomics of NGF-TrkA signaling identifies an inhibitory role for the E3 ligase Cbl-b in neuroblastoma cell differentiation
Authors: Emdal Kristina B. , Pedersen Anna-Kathrine , Bekker-Jensen Dorte B. , Tsafou Kalliopi P. , Horn Heiko , Lindner Sven , Schulte Johannes H. , Eggert Angelika , Jensen Lars J. , Francavilla Chiara , Olsen Jesper V.
Published: April 2015

Proteomic analysis of neurotrophin signaling identifies an inhibitory E3 ubiquitin ligase.
In vivo imaging of the spatiotemporal activity of the eIF2α-ATF4 signaling pathway: Insights into stress and related disorders
Authors: Chaveroux Cédric , Carraro Valérie , Canaple Laurence , Averous Julien , Maurin Anne-Catherine , Jousse Céline , Muranishi Yuki , Parry Laurent , Mesclon Florent , Gatti Evelina , Mallet Jacques , Ravassard Philippe , Pierre Philippe , Fafournoux Pierre , Bruhat Alain
Published: April 2015

A transgenic mouse model enables analysis of the involvement of a stress signaling pathway in liver fibrosis.
Intracellular pH gradient guides cells
Authors: VanHook Annalisa M.
Published: April 2015

An extracellular chemokine gradient drives formation of an intracellular pH gradient that guides directional cell migration.
Can a cough suppressant treat diabetes?
Authors: Prabakaran Sudhakaran
Published: April 2015

Inhibiting the glutamate receptor NMDAR in pancreatic β cells improves glucose tolerance in type 2 diabetes.
A genetic cause for severe influenza
Authors: Mueller Kristen L.
Published: April 2015

A mutation that reduces antiviral interferons underlies certain cases of severe influenza in children.
SARM1-driven axon degeneration
Authors: Ray L. Bryan
Published: April 2015

A critical role is elucidated for destruction of a metabolic cofactor in neuronal degeneration.
Immunotherapy according to GARP
Authors: Gough Nancy R.
Published: April 2015

Monoclonal antibodies that inhibit human T
reg
function may be used therapeutically in cancer or infections.
Interfering with viral neuroinvasion
Authors: Smith Orla
Published: April 2015

Interferon-λ signaling tightens the blood-brain barrier, limiting West Nile virus infection of the central nervous system.
Genetic Analyses of Penicillin Binding Protein Determinants in Multidrug-Resistant Streptococcus pneumoniae Serogroup 19 CC320/271 Clone with High-Level Resistance to Third-Generation Cephalosporins
Authors: Ip Margaret , Ang Irene , Liyanapathirana Veranja , Ma Helen , Lai Raymond
Published: April 2015

We describe the dissemination of a multidrug-resistant (MDR) serogroup 19 pneumococcal clone of representative multilocus sequence type 271 (ST271) with high-level resistance to cefotaxime in Hong Kong and penicillin binding protein (
pbp
) genes and its relationships to Taiwan
19F
-14 and the prevalent multidrug-resistant 19A clone (MDR19A-ST320). A total of 472 nonduplicate isolates from 2006 and 2011 were analyzed. Significant increases in the rates of nonsusceptibility to penicillin (PEN) (MIC ≥ 4.0 μg/ml; 9.9 versus 23.3%;
P
= 0.0005), cefotaxime (CTX) (MIC ≥ 2.0 μg/ml; 12.2 versus 30.3%;
P
< 0.0001 [meningitis MIC ≥ 1.0 μg/ml; 30.2 versus 48.7%;
P
= 0.0001]), and erythromycin (ERY) (69.2 versus 84.0%;
P
= 0.0003) were noted when rates from 2006 and 2011 were compared. The CTX-resistant isolates with MICs of 8 μg/ml in 2011 were of serotype 19F, belonging to ST271. Analyses of the penicillin binding protein 2x (PBP2x) amino acid sequences in relation to the corresponding sequences of the R6 strain revealed M339F, E378A, M400T, and Y595F substitutions found within the ST271 clone but not present in Taiwan
19F
-14 or MDR19A. In addition, PBP2bs of ST271 strains and that of the Taiwan
19F
-14 clone were characterized by a unique amino acid substitution, E369D, while ST320 possessed the unique amino acid substitution K366N, as does that of MDR19A in the United States. We hypothesize that ST271 originated from the Taiwan
19F
-14 lineage, which had disseminated in Hong Kong in the early 2000s, and conferred higher-level β-lactam and cefotaxime resistance through acquisitions of 19 additional amino acid substitutions in PBP2b (amino acid [aa] positions 538 to 641) and altered PBP2x via recombination events. The serogroup 19 MDR CC320/271 clone warrants close monitoring to evaluate its effect after the switch to expanded conjugate vaccines.
Stability of the Antimalarial Drug Dihydroartemisinin under Physiologically Relevant Conditions: Implications for Clinical Treatment and Pharmacokinetic and
In Vitro
Assays
Authors: Parapini Silvia , Olliaro Piero , Navaratnam Visweswaran , Taramelli Donatella , Basilico Nicoletta
Published: April 2015

Artemisinins are peroxidic antimalarial drugs known to be very potent but highly chemically unstable; they degrade in the presence of ferrous iron, Fe(II)-heme, or biological reductants. Less documented is how this translates into chemical stability and antimalarial activity across a range of conditions applying to
in vitro
testing and clinical situations. Dihydroartemisinin (DHA) is studied here because it is an antimalarial drug on its own and the main metabolite of other artemisinins. The behaviors of DHA in phosphate-buffered saline, plasma, or erythrocyte lysate at different temperatures and pH ranges were examined. The antimalarial activity of the residual drug was evaluated using the chemosensitivity assay on
Plasmodium falciparum
, and the extent of decomposition of DHA was established through use of high-performance liquid chromatography with electrochemical detection analysis. The role of the Fe(II)-heme was investigated by blocking its reactivity using carbon monoxide (CO). A significant reduction in the antimalarial activity of DHA was seen after incubation in plasma and to a lesser extent in erythrocyte lysate. Activity was reduced by half after 3 h and almost completely abolished after 24 h. Serum-enriched media also affected DHA activity. Effects were temperature and pH dependent and paralleled the increased rate of decomposition of DHA from pH 7 upwards and in plasma. These results suggest that particular care should be taken in conducting and interpreting
in vitro
studies, prone as their results are to experimental and drug storage conditions. Disorders such as fever, hemolysis, or acidosis associated with malaria severity may contribute to artemisinin instability and reduce their clinical efficacy.
The SmeYZ Efflux Pump of Stenotrophomonas maltophilia Contributes to Drug Resistance, Virulence-Related Characteristics, and Virulence in Mice
Authors: Lin Yi-Tsung , Huang Yi-Wei , Chen Shiang-Jiuun , Chang Chia-Wei , Yang Tsuey-Ching
Published: April 2015

The resistance-nodulation-division (RND)-type efflux pump is one of the causes of the multidrug resistance of
Stenotrophomonas maltophilia
. The roles of the RND-type efflux pump in physiological functions and virulence, in addition to antibiotic extrusion, have attracted much attention. In this study, the contributions of the constitutively expressed SmeYZ efflux pump to drug resistance, virulence-related characteristics, and virulence were evaluated.
S. maltophilia
KJ is a clinical isolate of multidrug resistance. The
smeYZ
isogenic deletion mutant, KJΔYZ, was constructed by a gene replacement strategy. The antimicrobial susceptibility, virulence-related physiological characteristics, susceptibility to human serum and neutrophils, and
in vivo
virulence between KJ and KJΔYZ were comparatively assessed. The SmeYZ efflux pump contributed resistance to aminoglycosides and trimethoprim-sulfamethoxazole. Inactivation of
smeYZ
resulted in attenuation of oxidative stress susceptibility, swimming, flagella formation, biofilm formation, and secreted protease activity. Furthermore, loss of SmeYZ increased susceptibility to human serum and neutrophils and decreased
in vivo
virulence in a murine model. These findings suggest the possibility of attenuation of the resistance and virulence of
S. maltophilia
with inhibitors of the SmeYZ efflux pump.
The Efflux Pump SmeDEF Contributes to Trimethoprim-Sulfamethoxazole Resistance in Stenotrophomonas maltophilia
Authors: Sánchez María Blanca , Martínez José Luis
Published: April 2015

Trimethoprim-sulfamethoxazole (co-trimoxazole) is one of the antimicrobials of choice for the treatment of
Stenotrophomonas maltophilia
infections. The analysis of mutants either lacking or overexpressing the efflux pump SmeDEF shows that this efflux pump contributes to intrinsic and acquired co-trimoxazole resistance in
S. maltophilia
. Since SmeDEF can extrude a variety of antibiotics, selection with such antimicrobials, including quinolones, might also select for
S. maltophilia
co-trimoxazole resistance.
Meropenem and Chromacef Intermediates Observed in IMP-25 Metallo-β-Lactamase-Catalyzed Hydrolysis
Authors: Oelschlaeger Peter , Aitha Mahesh , Yang Hao , Kang Joon S. , Zhang Antonia L. , Liu Eleanor M. , Buynak John D. , Crowder Michael W.
Published: April 2015

Metallo-β-lactamases inactivate most β-lactam antibacterials, and much attention has been paid to their catalytic mechanism. One issue of controversy has been whether β-lactam hydrolysis generally proceeds through an anionic intermediate bound to the active-site Zn(II) ions or not. The formation of an intermediate has not been shown conclusively in imipenemase (IMP) enzymes to date. Here, we provide evidence that intermediates are formed during the hydrolysis of meropenem and chromacef catalyzed by the variant IMP-25 and, to a lesser degree, IMP-1.
New
In Vitro
Model To Study the Effect of Human Simulated Antibiotic Concentrations on Bacterial Biofilms
Authors: Haagensen Janus A. J. , Verotta Davide , Huang Liusheng , Spormann Alfred , Yang Katherine
Published: April 2015

A new
in vitro
pharmacokinetic/pharmacodynamic simulator for bacterial biofilms utilizing flow cell technology and confocal laser scanning microscopy is described. The device has the ability to simulate the changing antibiotic concentrations in humans associated with intravenous dosing on bacterial biofilms grown under continuous culture conditions. The free drug concentrations of a single 2-g meropenem intravenous bolus dose and first-order elimination utilizing a half-life of 0.895 h (elimination rate constant, 0.776 h
−1
) were simulated. The antibacterial activity of meropenem against biofilms of
Pseudomonas aeruginosa
PAO1 and three clinical strains isolated from patients with cystic fibrosis was investigated. Additionally, the effect of meropenem on PAO1 biofilms cultured for 24 h versus that on biofilms cultured for 72 h was examined. Using confocal laser scanning microscopy, rapid biofilm killing was observed in the first hour of the dosing interval for all biofilms. However, for PAO1 biofilms cultured for 72 h, only bacterial subpopulations at the periphery of the biofilm were affected, with subpopulations at the substratum remaining viable, even at the conclusion of the dosing interval. The described model is a novel method to investigate antimicrobial killing of bacterial biofilms using human simulated concentrations.
Dynamic Virus-Bacterium Interactions in a Porcine Precision-Cut Lung Slice Coinfection Model: Swine Influenza Virus Paves the Way for Streptococcus suis Infection in a Two-Step Process
Authors: Meng F. , Wu N. H. , Nerlich A. , Herrler G. , Valentin-Weigand P. , Seitz M.
Published: April 2015

Swine influenza virus (SIV) and
Streptococcus suis
are common pathogens of the respiratory tract in pigs, with both being associated with pneumonia. The interactions of both pathogens and their contribution to copathogenesis are only poorly understood. In the present study, we established a porcine precision-cut lung slice (PCLS) coinfection model and analyzed the effects of a primary SIV infection on secondary infection by
S. suis
at different time points. We found that SIV promoted adherence, colonization, and invasion of
S. suis
in a two-step process. First, in the initial stages, these effects were dependent on bacterial encapsulation, as shown by selective adherence of encapsulated, but not unencapsulated,
S. suis
to SIV-infected cells. Second, at a later stage of infection, SIV promoted
S. suis
adherence and invasion of deeper tissues by damaging ciliated epithelial cells. This effect was seen with a highly virulent SIV subtype H3N2 strain but not with a low-virulence subtype H1N1 strain, and it was independent of the bacterial capsule, since an unencapsulated
S. suis
mutant behaved in a way similar to that of the encapsulated wild-type strain. In conclusion, the PCLS coinfection model established here revealed novel insights into the dynamic interactions between SIV and
S. suis
during infection of the respiratory tract. It showed that at least two different mechanisms contribute to the beneficial effects of SIV for
S. suis
, including capsule-mediated bacterial attachment to SIV-infected cells and capsule-independent effects involving virus-mediated damage of ciliated epithelial cells.
Role of Spermidine in Overwintering of Cyanobacteria
Authors: Zhu Xiangzhi , Li Qiong , Yin Chuntao , Fang Xiantao , Xu Xudong
Published: April 2015

Polyamines are found in all groups of cyanobacteria, but their role in environmental adaptation has been barely investigated. In
Synechocystis
sp. strain PCC 6803, inactivation of spermidine synthesis genes significantly reduced the survivability under chill (5°C)-light stress, and the survivability could be restored by addition of spermidine. To analyze the effects of spermidine on gene expression at 5°C,
lacZ
was expressed from the promoter of carboxy(nor)spermidine decarboxylase gene (
CASDC
) in
Synechocystis
.
Synechocystis
6803::P

CASDC

-
lacZ
pretreated at 15°C showed a high level of LacZ activity for a long period of time at 5°C; without the pretreatment or with protein synthesis inhibited at 5°C, the enzyme activity gradually decreased. In a spermidine-minus mutant harboring P

CASDC

-
lacZ
,
lacZ
showed an expression pattern as if protein synthesis were inhibited at 5°C, even though the stability of its mRNA increased. Four other genes, including
rpoA
that encodes the α subunit of RNA polymerase, showed similar expression patterns. The chill-light stress led to a rapid increase of protein carbonylation in
Synechocystis
. The protein carbonylation then quickly returned to the background level in the wild type but continued to slowly increase in the spermidine-minus mutant. Our results indicate that spermidine promotes gene expression and replacement of damaged proteins in cyanobacteria under the chill-light stress in winter.

IMPORTANCE
Outbreak of cyanobacterial blooms in freshwater lakes is a worldwide environmental problem. In the annual cycle of bloom-forming cyanobacteria, overwintering is the least understood stage. Survival of
Synechocystis
sp. strain PCC 6803 under long-term chill (5°C)-light stress has been established as a model for molecular studies on overwintering of cyanobacteria. Here, we show that spermidine, the most common polyamine in cyanobacteria, promotes the survivability of
Synechocystis
under long-term chill-light stress and that the physiological function is based on its effects on gene expression and recovery from protein damage. This is the first report on the role of polyamines in survival of overwintering cyanobacteria. We also analyzed spermidine synthesis pathways in cyanobacteria on the basis of bioinformatic and experimental data.
Interaction between Streptococcus spp. and Veillonella tobetsuensis in the Early Stages of Oral Biofilm Formation
Authors: Mashima Izumi , Nakazawa Futoshi
Published: April 2015

Dental plaque is a multispecies oral biofilm, the development of which is initiated by adherence of the pioneerStreptococcusspp. OralVeillonellaspp., includingV. atypica,V. denticariosi,V. dispar,V. parvula,V. rogosae, andV. tobetsuensis, are known as early colonizers in oral biofilm formation. These species have been reported to coaggregate withStreptococcusspp. in a metabolic cooperation-dependent manner to form biofilms in human oral cavities, especially in the early stages of biofilm formation. However, in our previous study,Streptococcus gordoniishowed biofilm formation to the greatest extent in the presence ofV. tobetsuensis, without coaggregation between species. These results suggest thatV. tobetsuensisproduces signaling molecules that promote the proliferation ofS. gordoniiin biofilm formation. It is well known in many bacterial species that the quorum-sensing (QS) system regulates diverse functions such as biofilm formation. However, little is known about the QS system with autoinducers (AIs) with respect toVeillonella and Streptococcusspp. Recently, autoinducer 1 (AI-1) and AI-2 were detected and identified in the culture supernatants ofV. tobetsuensisas strong signaling molecules in biofilm formation withS. gordonii. In particular, the supernatant fromV. tobetsuensisshowed the highest AI-2 activity among 6 oralVeillonellaspecies, indicating that AIs, mainly AI-2, produced byV. tobetsuensismay be important factors and may facilitate biofilm formation ofS. gordonii. Clarifying the mechanism that underlies the QS system betweenS. gordoniiandV. tobetsuensismay lead to the development of novel methods for the prevention of oral infectious diseases caused by oral biofilms.
Role and Function of LitR, an Adenosyl B
12
-Bound Light-Sensitive Regulator of Bacillus megaterium QM B1551, in Regulation of Carotenoid Production
Authors: Takano Hideaki , Mise Kou , Hagiwara Kenta , Hirata Naoya , Watanabe Shoko , Toriyabe Minami , Shiratori-Takano Hatsumi , Ueda Kenji
Published: April 2015

The LitR/CarH family of proteins is a light-sensitive MerR family of transcriptional regulators that contain an adenosyl B
12
(coenzyme B
12
or AdoB
12
)-binding domain at the C terminus. The genes encoding these proteins are found in phylogenetically diverse bacterial genera; however, the biochemical properties of these proteins from Gram-positive bacteria remain poorly understood. We performed genetic and biochemical analyses of a homolog of the LitR protein from
Bacillus megaterium
QM B1551, a Gram-positive endospore-forming soil bacterium. Carotenoid production was induced by illumination in this bacterium.
In vivo
analysis demonstrated that LitR plays a central role in light-inducible carotenoid production and serves as a negative regulator of the light-inducible transcription of
crt
and
litR
itself. Biochemical evidence showed that LitR in complex with AdoB
12
binds to the promoter regions of
litR
and the
crt
operon in a light-sensitive manner.
In vitro
transcription experiments demonstrated that AdoB
12
-LitR inhibited the specific transcription of the
crt
promoter generated by a σ
A
-containing RNA polymerase holoenzyme under dark conditions. Collectively, these data indicate that the AdoB
12
-LitR complex serves as a photoreceptor with DNA-binding activity in
B. megaterium
QM B1551 and that its function as a transcriptional repressor is fundamental to the light-induced carotenoid production.

IMPORTANCE
Members of the LitR/CarH family are AdoB
12
-based photosensors involved in light-inducible carotenoid production in nonphototrophic Gram-negative bacteria. Our study revealed that
Bacillus
LitR in complex with AdoB
12
also serves as a transcriptional regulator with a photosensory function, which indicates that the LitR/CarH family is generally involved in the light-inducible carotenoid production of nonphototrophic bacteria.
Shigella sonneibacteraemia occurring in a young man with shigellosis
Authors: Huynh Andrew , McGrath Christian , Johnson Douglas , Burrell Louise M
Published: April 2015

A 34-year-old man presented with a 6-day history of diarrhoea, abdominal cramps and fever. Blood cultures were initially reported as positive forEscherichia coliusing matrix-assisted laser desorption/ionisation time of flight (MALDI-TOF) mass spectrometry. Contrast CT of the abdomen and pelvis revealed pancolitis and terminal ileal thickening. The patient was treated empirically with ampicillin, ciprofloxacin and metronidazole. Stool cultures were positive forShigella sonnei. Subsequent testing on the initial blood culture correctly identified the organism asS. sonnei. On further questioning, the patient reported unprotected men who have sex with men (MSM) 3 months previously. His symptoms resolved during his 3-day admission, and he was discharged on 14 days of ciprofloxacin. He remains well. This case highlights that shigellosis is increasingly seen in MSM, with no history of travel, and may result in bacteraemia. This case also highlights the benefits (rapid identification of organisms) and limitations (inability to distinguish betweenE. coliandShigellaspp) of new technologies such as MALDI-TOF.
An 8-Bit 0.333–2 GS/s Configurable Time-Interleaved SAR ADC in 65-nm CMOS
Authors: Li Dengquan , Zhang Liang , Zhu Zhangming , Yang Yintang
Published: April 2015

This paper presents an 8-bit configurable time-interleaved (TI) successive approximation register (SAR) analog-to-digital converter (ADC). By using a mode selection circuit, four modes of sampling rate are provided: Single channel at 333.3 MS/s, 2-channel at 666.7 MS/s, 3-channel at 1 GS/s and 6-channel at 2 GS/s. An on-chip delay-locked loop (DLL) uniformly generates six-phase clock with 20% duty cycle, and the timing errors are reduced to a tolerable range. In low sampling rate modes, the corresponding sampling switches and comparators in the idle sub-ADCs are shut down to save power consumption. Based on the 65-nm CMOS technology, the post-layout simulation results show that at 1.2 V supply, the proposed ADC consumes 8.6, 10.9, 13.1 and 19.9 mW under different modes. With an ENOB of 7.92, 7.34, 7.01 and 6.37 bit, this results in a FOM of 106.6, 100.9, 101.6 and 120.3 fJ/conversion-step respectively.
Oscillating shells in Anti-de Sitter space
Authors: Mas Javier , Serantes Alexandre
Published: April 2015

We study the dynamics of a spherically symmetric thin shell of perfect fluid embedded in d-dimensional Anti-de Sitter (AdS) spacetime. In global coordinates, besides collapsing solutions, oscillating solutions are found where the shell bounces back and forth between two radii. The parameter space where these oscillating solutions exist is scanned in arbitrary number of dimensions. As expected, AdS3 appears to be singled out.
EFFECT OF ANNEALING TEMPERATURE ON HARDNESS AND WEAR RESISTANCE OF ELECTROLESSNi–B–MoCOATINGS
Authors: SERIN IHSAN GÖKHAN , GÖKSENLI ALI
Published: April 2015

Formation of nickel–boron–molybdenum ( Ni – B – Mo ) coating on steel by electroless plating and evaluation of their morphology, hardness and tribological properties post heat treatment at different temperatures for 1 h is investigated. The 25 μm thick coating is uniform and adhesion between the substrate and coating is good. Ni – B – Mo coating was amorphous-like structure in their as-plated condition and by 400°C heat-treated coating, nickel fully crystallized and nickel borides and molybdenum carbide were formed. All coatings exhibited higher hardness than the substrate steel. Hardness values of all coatings up to 400°C did not change distinctively but decreased partly beyond 400°C. Friction coefficient reached lowest value post heat treatment at 300°C but later increased with increasing tempering temperature. Wear resistance was lowest in as-plated coating; however it reached the highest value at 300°C. Worn surface of the coatings showed the abrasive wear as the dominant wear mechanism. An additional adhesive wear mechanism was detected in coating tempered at 550°C. Moreover, our results confirmed that the molybdenum addition improved the thermal stability of the resulting coating. Therefore, Ni – B – Mo coating has potential for application in precision mould, optical parts mould or bipolar plates, where thermal stability is essential.
Large deviations for a fractional stochastic heat equation in spatial dimension ℝd driven by a spatially correlated noise
Authors: El Mellali Tarik , Mellouk Mohamed
Published: April 2015

In this paper we study the Large Deviations Principle (LDP in abbreviation) for a class of Stochastic Partial Differential Equations (SPDEs) in the whole space [Formula: see text], with arbitrary dimension [Formula: see text], under random influence which is a Gaussian noise, white in time and correlated in space. The differential operator is a fractional derivative operator. We prove a Large deviations principle for our equation, using a weak convergence approach based on a variational representation of functionals of infinite-dimensional Brownian motion. This approach reduces the proof of LDP to establishing basic qualitative properties for controlled analogues of the original stochastic system.
Modeling the Relationship between Human Intelligence, Knowledge Management Practices, and Innovation Performance
Authors: Noordin M. F. , Karim Z. A.
Published: April 2015

Pioneers in knowledge management (KM) have well articulated the relationship between KM and innovation. In addition, there are many theoretical papers as well as empirical studies that examined the positive relationship between KM and innovation. However, these empirical studies analysed the relationship between KM and innovation at management or organisational level. There is a need to study this relationship at the knowledge workers level to see how they actually influence their organisational KM and innovation. This study aims to analyse the knowledge worker's intelligence, emotional, and spiritual potential towards KM and innovation as well as examine the relationship between knowledge workers, KM and innovation. Survey questionnaires are used to measure knowledge workers' intelligence quotient (IQ), emotional quotient (EQ), and spiritual quotient (SQ), their KM processes involvement, and perception on their innovation performance. Partial least square (PLS) analysis is used in the analyses to determine the relationship between human intelligence, KM processes and innovation performance. Results indicate that human EQ and SQ influenced KM and innovation but not IQ.
Topological basis realization for BMW algebra and Heisenberg XXZ spin chain model
Authors: Liu Bo , Xue Kang , Wang Gangcheng , Liu Ying , Sun Chunfang
Published: April 2015

In this paper, we study three-dimensional (3D) reduced Birman–Murakami–Wenzl (BMW) algebra based on topological basis theory. Several examples of BMW algebra representations are reviewed. We also discuss a special solution of BMW algebra, which can be used to construct Heisenberg XXZ model. The theory of topological basis provides a useful method to solve quantum spin chain models. It is also shown that the ground state of XXZ spin chain is superposition state of topological basis.
Growth Mechanism and Electrochemical Properties of Porous Hollow Tin Dioxide Nanospheres
Authors: Yang Youwen , Ma Dongming , Cheng Ting , Gao Yuanhao , Li Guanghai
Published: April 2015

Porous hollow SnO 2 nanospheres were prepared by means of enforced Sn 2+ hydrolysis method under hydrochloric acid medium. These hollow nanospheres with an average diameter of 220nm had a very thin shell thickness of about 40nm and were surrounded by elongated octahedral-like nanoparticles with the apex oriented outside. The experimental conditions, such as HCl content, reaction temperature and time directly dominated the morphology, structure and crystallinity of the obtained samples. A pre-oxidation-nucleation-growth mechanism and inside-out Ostwald-ripening method was proposed on the basis of the previous research and time-dependent experiments. Electrochemical tests showed that the porous hollow SnO 2 nanospheres exhibited improved cycling performance for anode materials of lithium-ion batteries, which retained a high reversible capacity of 540.0mAhg-1, and stable cyclic retention at 120th cycle.
FMR1 Deficiency Alters Self-Renewal and Proliferation of Mouse Embryonic Cells
Authors: Bale Shyam Sundhar , Saeidi Nima , Kidambi Srivatsan , Yarmush Martin L. , Casali Monica
Published: April 2015

The regulation of embryonic stem (ES) cell self-renewal and pluripotency is based upon highly orchestrated transcription factor networks. RNA inhibition has been demonstrated to affect ES cell function by altering gene expression levels that are critical to the maintenance and differentiation of ES cells. Fragile X mental retardation protein (FMRP) is a selective RNA-binding protein that can act as a translational repressor for bound mRNA and regulates the expression of a variety of gene transcripts in numerous adult cells. The absence of FMRP results in the most common form of inherited intellectual disability, Fragile X syndrome. In an effort to determine the role of FMRP during development, we silenced the FMRP gene (FMR1) using short hairpin RNA (shRNA). Prior to differentiation induction, we analyzed the phenotype of FMR1 knock down (FMR1-kd) mouse ES cells in their undifferentiated state. Herein, we report that FMR1-kd ES cells proliferate at a greater rate than wild-type ES cells resulting in a 25% reduction in doubling time. FMR1-kd ES cells were found to have an increased expression of three self-renewal genes (OCT-4, Sox2, Nanog) in the undifferentiated state. Moreover, FMR1-kd ES cells failed to downregulate OCT-4 during differentiation programs resulting in abnormal fate decisions in vitro. These results demonstrate an unexpected correlation between FMR1 expression and OCT-4 regulation suggesting that FMRP is involved in the silencing of OCT-4 during the commencement of differentiation programs.
Fully Binary Neural Network Model and Optimized Hardware Architectures for Associative Memories
Authors: Coussy Philippe , Chavet Cyrille , Wouafo Hugues Nono , Conde-Canencia Laura
Published: April 2015

Brain processes information through a complex hierarchical associative memory organization that is distributed across a complex neural network. The GBNN associative memory model has recently been proposed as a new class of recurrent clustered neural network that presents higher efficiency than the classical models. In this article, we propose computational simplifications and architectural optimizations of the original GBNN. This work leads to significant complexity and area reduction without affecting neither memorizing nor retrieving performance. The obtained results open new perspectives in the design of neuromorphic hardware to support large-scale general-purpose neural algorithms.