bluuebunny/crossref_metadata_2025 huggingface dataset:
In Vitro
Activity of RX-P873 against Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii
Authors: Flamm Robert K. , Rhomberg Paul R. , Jones Ronald N. , Farrell David J.
Published: February 2015

RX-P873 is a novel antibiotic from the pyrrolocytosine series which exhibits high binding affinity for the bacterial ribosome and broad-spectrum antibiotic properties. The pyrrolocytosines have shown
in vitro
activity against multidrug-resistant Gram-negative and Gram-positive strains of bacteria known to cause complicated urinary tract, skin, and lung infections, as well as sepsis.
Enterobacteriaceae
(657),
Pseudomonas aeruginosa
(200), and
Acinetobacter baumannii
(202) isolates from North America and Europe collected in 2012 as part of a worldwide surveillance program were tested
in vitro
by broth microdilution using Clinical and Laboratory Standards Institute (CLSI) methodology. RX-P873 (MIC
90
, 0.5 μg/ml) was >32-fold more active than ceftazidime and inhibited 97.1% and 99.5% of
Enterobacteriaceae
isolates at MIC values of ≤1 and ≤4 μg/ml, respectively. There were only three isolates with an MIC value of >4 μg/ml (all were indole-positive
Protea
). RX-P873 (MIC
50/90
, 2/4 μg/ml) was highly active against
Pseudomonas aeruginosa
isolates, including isolates which were nonsusceptible to ceftazidime or meropenem. RX-P873 was 2-fold less active against
P. aeruginosa
than tobramycin (MIC
90
, 2 μg/ml; 91.0% susceptible) and colistin (MIC
90
, 2 μg/ml; 99.5% susceptible) and 2-fold more potent than amikacin (MIC
90
, 8 μg/ml; 93.5% susceptible) and meropenem (MIC
90
, 8 μg/ml; 76.0% susceptible). RX-P873, the most active agent against
Acinetobacter baumannii
(MIC
90
, 1 μg/ml), was 2-fold more active than colistin (MIC
90
, 2 μg/ml; 97.0% susceptible) and 4-fold more active than tigecycline (MIC
90
, 4 μg/ml). This novel agent merits further exploration of its potential against multidrug-resistant Gram-negative bacteria.
Search for Novel Candidate Mutations for Metronidazole Resistance in Helicobacter pylori Using Next-Generation Sequencing
Authors: Binh Tran Thanh , Suzuki Rumiko , Trang Tran Thi Huyen , Kwon Dong Hyeon , Yamaoka Yoshio
Published: February 2015

Metronidazole resistance is a key factor associated with
Helicobacter pylori
treatment failure. Although this resistance is mainly associated with mutations in the
rdxA
and
frxA
genes, the question of whether metronidazole resistance is caused by the inactivation of
frxA
alone is still debated. Furthermore, it is unclear whether there are other mutations involved in addition to the two genes that are associated with resistance. A metronidazole-resistant strain was cultured from the metronidazole-susceptible
H. pylori
strain 26695-1 by exposure to low concentrations of metronidazole. The genome sequences of both susceptible and resistant
H. pylori
strains were determined by Illumina next-generation sequencing, from which putative candidate resistance mutations were identified. Natural transformation was used to introduce PCR products containing candidate mutations into the susceptible parent strain 26695-1, and the metronidazole MIC was determined for each strain. Mutations in
frxA
(
hp0642
),
rdxA
(
hp0954
), and
rpsU
(
hp0562
) were confirmed by the Sanger method. The mutated sequence in
rdxA
was successfully transformed into strain 26695-1, and the transformants showed resistance to metronidazole. The transformants containing a single mutation in
rdxA
showed a low MIC (16 mg/liter), while those containing mutations in both
rdxA
and
frxA
showed a higher MIC (48 mg/liter). No transformants containing a single mutation in
frxA
or
rpsU
were obtained. Next-generation sequencing was used to identify mutations related to drug resistance. We confirmed that the mutations in
rdxA
are mainly associated with metronidazole resistance, and mutations in
frxA
are able to enhance
H. pylori
resistance only in the presence of
rdxA
mutations. Moreover, mutations in
rpsU
may play a role in metronidazole resistance.
Modification of the CpsA Protein Reveals a Role in Alteration of the Streptococcus agalactiae Cell Envelope
Authors: Rowe Hannah M. , Hanson Brett R. , Runft Donna L. , Lin Qian , Firestine Steve M. , Neely Melody N.
Published: February 2015

The bacterial cell envelope is a crucial first line of defense for a systemic pathogen, with production of capsular polysaccharides and maintenance of the peptidoglycan cell wall serving essential roles in survival in the host environment. The LytR-CpsA-Psr proteins are important for cell envelope maintenance in many Gram-positive species. In this study, we examined the role of the extracellular domain of the CpsA protein of the zoonotic pathogen group B
Streptococcus
in capsule production and cell wall integrity. CpsA has multiple functional domains, including a DNA-binding/transcriptional activation domain and a large extracellular domain. We demonstrated that episomal expression of extracellularly truncated CpsA causes a dominant-negative effect on capsule production when expressed in the wild-type strain. Regions of the extracellular domain essential to this phenotype were identified. The dominant-negative effect could be recapitulated by addition of purified CpsA protein or a short CpsA peptide to cultures of wild-type bacteria. Changes in cell wall morphology were also observed when the dominant-negative peptide was added to wild-type cultures. Fluorescently labeled CpsA peptide could be visualized bound at the mid-cell region near the division septae, suggesting a novel role for CpsA in cell division. Finally, expression of truncated CpsA also led to attenuation of virulence in zebrafish models of infection, to levels below that of a
cpsA
deletion strain, demonstrating the key role of the extracellular domain in virulence of GBS.
Essential Engagement of Toll-Like Receptor 2 in Initiation of Early Protective Th1 Response against Rough Variants of Mycobacterium abscessus
Authors: Kim Jong-Seok , Kang Min-Jung , Kim Woo Sik , Han Seung Jung , Kim Hong Min , Kim Ho Won , Kwon Kee Woong , Kim So Jeong , Cha Seung Bin , Eum Seok-Yong , Koh Won-Jung , Cho Sang-Nae , Park Jong-Hwan , Shin Sung Jae
Published: February 2015

Although
Mycobacterium abscessus
(
M. abscessus
) is becoming more prevalent in patients without overt immunodeficiency, little is known about the factors that contribute to disease susceptibility. This study was undertaken to investigate how Toll-like receptor 2 (TLR2) functionally contributes to the generation of protective immunity against
M. abscessus
in a morphotype-specific manner. We found that
Tlr2
−/−
mice were extremely susceptible to an intravenous (i.v.) model of infection by
M. abscessus
rough variants, displaying uncontrolled infection in the lungs and a significantly lower survival rate than with wild-type (WT) mice. This uncontrolled infection resulted from failures in the following processes: (i) production of the crucial cytokines gamma interferon (IFN-γ), tumor necrosis factor alpha (TNF-α), and interleukin 12p70 (IL-12p70); (ii) early infiltration of neutrophils, monocytes, and dendritic cells (DCs) in the lungs of
Tlr2
−/−
mice; (iii) rapid influx of CD4
+
and CD8
+
T cells; and (iv) the expansion of memory/effector T cells. Notably, systemic administration of
M. abscessus
culture filtrate-treated syngeneic DCs from WT mice greatly strengthened immune priming
in vivo
, resulting in a dramatic reduction in bacterial growth and improved long-term survival in
Tlr2
−/−
mice, with a recovery of protective immunity. Our findings demonstrate that TLR2 is an essential contributor to instructive and effector immunity during
M. abscessus
infection in a morphotype-specific manner.
Characterization of a Novel Two-Component Regulatory System, HptRS, the Regulator for the Hexose Phosphate Transport System in Staphylococcus aureus
Authors: Park Joo Youn , Kim Jong Wan , Moon Bo Youn , Lee Juyeun , Fortin Ye Ji , Austin Frank W. , Yang Soo-Jin , Seo Keun Seok
Published: February 2015

Hexose phosphate is an important carbon source within the cytoplasm of host cells. Bacterial pathogens that invade, survive, and multiply within various host epithelial cells exploit hexose phosphates from the host cytoplasm through the
h
exose
p
hosphate
t
ransport (HPT) system to gain energy and synthesize cellular components. In
Escherichia coli
, the HPT system consists of a two-component regulatory system (UhpAB) and a phosphate sensor protein (UhpC) that tightly regulate expression of a hexose phosphate transporter (UhpT). Although growing evidence suggests that
Staphylococcus aureus
also can invade, survive, and multiply within various host epithelial cells, the genetic elements involved in the HPT system in
S. aureus
have not been characterized yet. In this study, we identified and characterized the HPT system in
S. aureus
that includes the
hptRS
(a novel two-component regulatory system), the
hptA
(a putative phosphate sensor), and the
uhpT
(a hexose phosphate transporter) genes. The
hptA
,
hptRS
, and
uhpT
markerless deletion mutants were generated by an allelic replacement method using a modified pMAD-CM-GFPuv vector system. We demonstrated that both
hptA
and
hptRS
are required to positively regulate transcription of
uhpT
in response to extracellular phosphates, such as glycerol-3-phosphate (G3P), glucose-6-phosphate (G6P), and fosfomycin. Mutational studies revealed that disruption of the
hptA
,
hptRS
, or
uhpT
gene impaired the growth of bacteria when the available carbon source was limited to G6P, impaired survival/multiplication within various types of host cells, and increased resistance to fosfomycin. The results of this study suggest that the HPT system plays an important role in adaptation of
S. aureus
within the host cells and could be an important target for developing novel antistaphylococcal therapies.
Comparative Genome Sequencing of Rickettsia rickettsii Strains That Differ in Virulence
Authors: Clark Tina R. , Noriea Nicholas F. , Bublitz DeAnna C. , Ellison Damon W. , Martens Craig , Lutter Erika I. , Hackstadt Ted
Published: February 2015

Rickettsia rickettsii
is an obligate intracellular pathogen that is the causative agent of Rocky Mountain spotted fever. Strains of
R. rickettsii
differ dramatically in virulence. In a guinea pig model of infection, the severity of disease as assessed by fever response varies from the most virulent, Sheila Smith, to Iowa, which causes no fever. To identify potential determinants of virulence in
R. rickettsii
, the genomes of two additional strains were sequenced for comparison to known sequences (comparative genome sequencing [CGS]).
R. rickettsii
Morgan and R strains were compared to the avirulent
R. rickettsii
Iowa and virulent
R. rickettsii
Sheila Smith strains. The Montana strains Sheila Smith and R were found to be highly similar while the eastern strains Iowa and Morgan were most similar to each other. A major surface antigen, rickettsial outer membrane protein A (rOmpA), is severely truncated in the Iowa strain. The region of
ompA
containing 13 tandem repeats was sequenced, revealing only seven shared SNPs (four nonsynonymous) for R and Morgan strains compared to Sheila Smith, with an additional 17 SNPs identified in Morgan. Another major surface antigen and autotransporter, rOmpB, exhibits a defect in processing in the Iowa strain such that the beta fragment is not cleaved. Sequence analysis of
ompB
reveals identical sequences between Iowa and Morgan strains and between the R and Sheila Smith strains. The number of SNPs and insertions/deletions between sequences of the two Montana strains and the two eastern strains is low, thus narrowing the field of possible virulence factors.
Genome-Based Analysis and Gene Dosage Studies Provide New Insight into 3-Hydroxy-4-Methylvalerate Biosynthesis in Ralstonia eutropha
Authors: Saika Azusa , Ushimaru Kazunori , Mizuno Shoji , Tsuge Takeharu
Published: February 2015

Recombinant
Ralstonia eutropha
strain PHB
−
4 expressing the broad-substrate-specificity polyhydroxyalkanoate (PHA) synthase 1 from
Pseudomonas
sp. strain 61-3 (PhaC1
Ps
) synthesizes a PHA copolymer containing the branched side-chain unit 3-hydroxy-4-methylvalerate (3H4MV), which has a carbon backbone identical to that of leucine. Mutant strain 1F2 was derived from
R. eutropha
strain PHB
−
4 by chemical mutagenesis and shows higher levels of 3H4MV production than does the parent strain. In this study, to understand the mechanisms underlying the enhanced production of 3H4MV, whole-genome sequencing of strain 1F2 was performed, and the draft genome sequence was compared to that of parent strain PHB
−
4. This analysis uncovered four point mutations in the 1F2 genome. One point mutation was found in the
ilvH
gene at amino acid position 36 (A36T) of IlvH.
ilvH
encodes a subunit protein that regulates acetohydroxy acid synthase III (AHAS III). AHAS catalyzes the conversion of pyruvate to 2-acetolactate, which is the first reaction in the biosynthesis of branched amino acids such as leucine and valine. Thus, the A36T IlvH mutation may show AHAS tolerance to feedback inhibition by branched amino acids, thereby increasing carbon flux toward branched amino acid and 3H4MV biosynthesis. Furthermore, a gene dosage study and an isotope tracer study were conducted to investigate the 3H4MV biosynthesis pathway. Based on the observations in these studies, we propose a 3H4MV biosynthesis pathway in
R. eutropha
that involves a condensation reaction between isobutyryl coenzyme A (isobutyryl-CoA) and acetyl-CoA to form the 3H4MV carbon backbone.
devIIs an Evolutionarily Young Negative Regulator of Myxococcus xanthus Development
Authors: Rajagopalan Ramya , Wielgoss Sébastien , Lippert Gerardo , Velicer Gregory J. , Kroos Lee
Published: February 2015

During starvation-induced development ofMyxococcus xanthus, thousands of rod-shaped cells form mounds in which they differentiate into spores. Thedevlocus includes eight genes followed by clustered regularly interspaced short palindromic repeats (CRISPRs), comprising a CRISPR-Cas system (Cas stands for CRISPR associated) typically involved in RNA interference. Mutations indevSordevRof a lab reference strain permit mound formation but impair sporulation. We report that natural isolates ofM. xanthuscapable of normal development are highly polymorphic in the promoter region of thedevoperon. We show that thedevpromoter is predicted to be nonfunctional in most natural isolates and is dispensable for development of a laboratory reference strain. Moreover, deletion of thedevpromoter or the small gene immediately downstream of it, here designateddevI(developmentinhibitor), suppressed the sporulation defect ofdevSordevRmutants in the lab strain. Complementation experiments and the result of introducing a premature stop codon indevIsupport a model in which DevRS proteins negatively autoregulate expression ofdevI, whose 40-residue protein product DevI inhibits sporulation if overexpressed. DevI appears to act in a cell-autonomous manner since experiments with conditioned medium and with cell mixtures gave no indication of extracellular effects. Strikingly, we report thatdevIis entirely absent from mostM. xanthusnatural isolates and was only recently integrated into the developmental programs of some lineages. These results provide important new insights into both the evolutionary history of thedevoperon and its mechanistic role inM. xanthussporulation.

IMPORTANCECertain mutations in thedevCRISPR-Cas (clustered regularly interspaced short palindromic repeat-associated) system ofMyxococcus xanthusimpair sporulation. The link between development and a CRISPR-Cas system has been a mystery. Surprisingly, DNA sequencing of natural isolates revealed that many appear to lack a functionaldevpromoter, yet these strains sporulate normally. Deletion of thedevpromoter or the small gene downstream of it suppressed the sporulation defect of a lab strain with mutations indevgenes encoding Cas proteins. The results support a model in which the Cas proteins DevRS prevent overexpression of the small genedevI, which codes for an inhibitor of sporulation. Phylogenetic analysis of natural isolates suggests thatdevIand thedevpromoter were only recently acquired in some lineages.
Subtalar dislocation secondary to a low energy injury
Authors: McKeag Philip , Lyske Jonathan , Reaney Jonathan , Thompson Neville
Published: February 2015

An 18-year-old young man presented with an ankle injury, after landing on a supinated right foot following jumping while playing football. A plain X-ray revealed a medial subtalar dislocation. Despite obvious ankle deformity, the surrounding skin remained intact. Closed reduction of the subtalar joint was successfully performed under general anaesthesia in theatre. A CT of the ankle, after reduction, demonstrated a non-displaced fracture of the neck of the talus; no osteochondral defect was observed. This was successfully managed conservatively, with immobilisation of the ankle, in a non-weight bearing cast for 6 weeks. This case highlights that subtalar dislocation may follow a low-energy mechanism and that such injuries can be managed without open reduction.
The prevalence, incidence and severity of low back pain among international-level rowers
Authors: Newlands Craig , Reid Duncan , Parmar Priya
Published: February 2015

Background/aims

There is a paucity of prospective cohort studies investigating the incidence of low back pain (LBP) in rowing. We investigated (1) the prevalence and incidence of LBP among international-level rowers in New Zealand, (2) the relationship between training volume and LBP and (3) the effect of LBP on rowers’ ability to train and compete.

Methods

This was a prospective cohort study of 76 New Zealand representative rowers, including 46 men (mean age 22, SD=4) and 30 women (mean age 21, SD=4). Data were collected using an online questionnaire repeated monthly for 12 months.

Results

The prevalence of LBP ranged from 6% to 25% throughout the year. The incidence of episodes of LBP was 1.67 per 1000 exposure-hours. A total of 72 episodes of LBP were reported by 40 rowers (53%) during 12 months. Of these, 45% had an incidental effect on training. 29% minor, 18% moderate and 9% had a major effect as determined by the length of time the training was interrupted. There was a high correlation between new LBP and total training hours per month (r=0.83, p<0.01). A previous history of LBP was a risk factor in developing new LBP (OR 2.06, 95% CI 1.22 to 3.48, p=0.01). Age was also a risk factor, with the likelihood of developing LBP increasing for every year (OR 1.08, 95% CI 1.01 to 1.15, p=0.02).

Conclusions

LBP is common among New Zealand representative rowers. There is a high correlation between training load and the development of LBP.
Characterizing patterns of endothelialization following coil embolization: a whole-mount, dual immunostaining approach
Authors: Dai Daying , Ding Yong-Hong , Rezek Issa , Kallmes David F , Kadirvel Ramanathan
Published: February 2015

Background

The extent, rate, and source of endothelialization following coil embolization of saccular aneurysms remains poorly understood. We performed a whole tissue mount, dual immunohistochemical analysis of experimental aneurysms to characterize the state of endothelialization over time after platinum coil embolization.

Method and material

Elastase-induced rabbit aneurysms were created and treated with bare platinum coils. Samples were harvested at 4 and 8 weeks (n=6 for each). En face whole tissue mount staining with antibodies to CD31 and α-smooth muscle actin was used to identify endothelial cells and smooth muscle cells, respectively. Sytox green stain was used to demonstrate nuclear morphology for identification of inflammatory cells. The extent of endothelialization was measured in relation to the aneurysm neck–parent artery interface.

Results

At 4 weeks after coil embolization, very localized membranous tissue and neoendothelial cells were detected on the coil loops immediately adjacent to the parent artery–neck interface, but the remainder of the coil loops remained devoid of endothelial cells. At 8 weeks neoendothelial cells were more confluent over the coils than at 4 weeks, and extended up to 900 µm from the parent artery–neck interface. However, the surfaces of the coils farther away than this region harbored no endothelial cells. Scattered inflammatory cells, including neutrophils and monocytes, were seen on the coil surface at the neck central area, where the coil surface was bare at the 4 and 8 weeks’ follow-up.

Conclusions

Platinum coil embolization supports gradual but limited endothelialization, where endothelial cells migrate directly from the adjacent parent artery.
Republished: Successfully treated symptomatic fusiform basilar artery aneurysm in a patient with hindbrain malformation via inverted Y-stenting
Authors: Purakal Alixandra S , Ginat Daniel Thomas , Lee Seon-Kyu
Published: February 2015

A double overlapping reverse Y-stent approach to creating flow diversion using traditional open-cell stent technology was evaluated as a treatment option symptomatic fusiform basilar aneurysms. A 36-year-old man with a complex hindbrain malformation presented with acute ocular dysmotility due to a rapidly enlarging fusiform basilar artery aneurysm. The aneurysm was treated by insertion of two stents into the vertebrobasilar system in an inverted Y-configuration from the basilar tip to the V4 segments of the bilateral vertebral arteries, essentially creating flow diversion without using a dedicated flow diversion device. This resulted in immediate symptomatic improvement. The stents remained patent and the aneurysm was obliterated at 6 months follow-up. Furthermore, the patient remained free of associated symptoms at 10 months follow-up. Thus, the double stenting technique can be used instead of a flow diversion device to effectively create flow diversion, promote aneurysm sac thrombosis, and lead to resolution of symptoms in large fusiform basilar artery aneurysms.
Genetic diversity and population structure of pencil yam (Vigna lanceolata) (Phaseoleae, Fabaceae), a wild herbaceous legume endemic to Australia, revealed by microsatellite markers
Authors: Nubankoh Phakchana , Pimtong Sarocha , Somta Prakit , Dachapak Sujinna , Srinives Peerasak
Published: February 2015

Pencil yam (Vigna lanceolata Benth.) (Phaseoleae, Fabaceae) is a herbaceous legume endemic to Australia. A previous morphological study suggested that pencil yam is a complex species of two or more related taxa with seven distinct morphological types (morphotypes) and, thus, taxonomic revision is necessary. In this study, we assessed genetic diversity and determined the genetic structure of a pencil yam collection of 62 accessions from seven morphotypes using 18 microsatellite (simple sequence repeat) markers with the aim to provide information for taxonomic study. In total, 138 alleles were detected with a mean of 7.67 alleles per locus. Polymorphism information content per marker varied between 0.06 and 0.90 with a mean of 0.61, while the overall gene diversity was 0.62. Bayesian clustering, principal coordinate, and neighbor-joining analyses consistently revealed that these accessions are grouped into two subpopulations with difference in number of alleles, allelic richness, and gene diversity. The population structure was not related to either morphotype or geographical origin. Gene diversity of V. lanceolata was higher than that of wild Vigna radiata (L.) Wilczek and wild Vigna umbellata (Thunb.) Ohwi & Ohashi, comparable with that of wild Vigna mungo (L.) Hepper, Vigna exilis Tateishi & Maxted, and Vigna grandiflora (Prain) Tateishi & Maxted, and lower than that of wild Vigna angularis (Willd.) Ohwi & Ohashi. These results indicated that the taxonomy of V. lanceolata should be revised and that its gene diversity was moderate compared with the other wild Vigna species.
Raman spectra measurements on DEPC liposome and cell membrane of living neuron under xenon pressure
Authors: Uchida Tsutomu , Nagayama Masafumi , Yamazaki Kenji , Gohara Kazutoshi , Sum Amadeu K.
Published: February 2015

The Raman spectra of liposomes were measured under xenon pressures and low temperatures to observe the spectra changes accompanying the gel to liquid crystalline phase transition of the liposomes. C–H stretching bonds of the lipids in the liposome were slightly red shifted at approximately 285 K and atmospheric pressure, which coincided well with the phase transition condition. This Raman peak shift was observed at lower temperatures and related linearly to the xenon pressures. The xenon pressure dependence on the phase transition temperature was in good agreement with the DSC measurements, and the red shifts of Raman peaks supported the molecular mechanism of interaction between xenon and phospholipid bilayers suggested by the MD simulations. The phase transition measurements under xenon pressure with the microscopic Raman spectroscopy were applied to cultured neuronal networks to observe the interaction of dissolved xenon with the cell membrane and the surrounding water.
Causal structure and birefringence in nonlinear electrodynamics
Authors: de Melo C. A. M. , Medeiros L. G. , Pompeia P. J.
Published: February 2015

We investigate the causal structure of general nonlinear electrodynamics and determine which Lagrangians generate an effective metric conformal to Minkowski. We also prove that there is only one analytic nonlinear electrodynamics not presenting birefringence.
Kinematics of ultra-high energy particle collisions near black holes in the magnetic field
Authors: Zaslavskii O. B.
Published: February 2015

There are different versions of collisions of two particles near black holes with unbound energy E cm in the center of mass frame. The so-called BSW effect arises when a slow fine-tuned "critical" particle hits a rapid "usual" one. We discuss a scenario of collision in the strong magnetic field for which explanation turns out to be different. Both particles are rapid but the nonzero angle between their velocities (which are both close to c, the speed of light) results in a relative velocity close to c and, hence, big E cm .
Damage Detection Based on Structural Responses Induced by Traffic Load: Methodology and Application
Authors: Sun Shouwang , Sun Limin , Chen Lin
Published: February 2015

In consideration of the important role that bridges play in transportation system, their safety, durability and serviceability have always been deeply concerned. Recently, many long-span bridges have been instrumented with Structural Health Monitoring Systems (SHMS) to provide bridge engineers with the information needed for decisions-making in management and maintenance. However, efficient use of monitoring data remains a challenge confronted before engineers. Recently, methodologies based on monitoring data while robust to random disturbance and sensitive to damage have received worldwide attention. In this context, this study proposes an innovative damage detection methodology based on structural responses induced by traffic load. First, vehicle-induced strain responses are found to be separable from the strain induced by operational loads, owing to their unique characteristics. This is achieved by a detailed investigation on the relationship between strain measurements and operational loads including temperature, wind as well as vehicles based on long-term monitoring data. From the vehicular load and pertinent strain response, the strain influence line (SIL) can be further identified. As a structural signature, SIL can be used to provide a reasonable assessment of the bridge health condition at least in the vicinity of strain monitoring point. Two damage indexes are therefore derived from the identified SIL, which are promising for damage evaluation because they are: (a) capable of revealing structural deterioration; (b) immune to influences of environmental changes; (c) adaptable to the random characteristic exhibited by long-term monitoring data. Besides, the SIL identification procedure and its theoretical basis are elaborated to respectively handle the case where the vehicle load is available or not, which is also applicable to identify the influence line of other measurements such as stresses. The proposed damage methodology is applied to the cable-stayed bridge spanning the main navigation channel of Shanghai Yangtze River Bridge, and the result shows its effectiveness.
Statistics of transitions for Markov chains with periodic forcing
Authors: Herrmann Samuel , Landon Damien
Published: February 2015

The influence of a time-periodic forcing on stochastic processes can essentially be emphasized in the large time behaviour of their paths. The statistics of transition in a simple Markov chain model permits to quantify this influence. In particular a functional Central Limit Theorem can be proven for the number of transitions between two states chosen in the whole finite state space of the Markov chain. An application to the stochastic resonance is presented.
Development of a 1 L/h Scale Liquid Hydrogen System
Authors: Garceau N. M. , Baik J. H. , Kim S. Y. , Oh I. H. , Karng S. W.
Published: February 2015

A small-scale hydrogen liquefaction plant consists of cryocooler, cryostat, liquid nitrogen (LN2) precooling bath, two ortho–para (o–p) hydrogen converters, a heat pipe, multilayer insulations (MLI), sensors and auxiliary components. The liquefaction plant was designed as both a cryocooler-cooled liquefier and a long-term zero boil-off liquid storage reservoir. A Gifford–McMahon (GM) cryocooler was selected as a cold sink and purchased from Cryomech Inc. A vacuum-jacketed 200 L capacity cryostat was designed to provide highly efficient thermal protection to LH2 storage space. A heat pipe was uniquely designed and installed in the cryostat to enhance heat transfer between the cryocooler and hydrogen gas and liquid. A LN2-cooled precooling bath was designed to act as a precooler and an o–p hydrogen converter. MLT blankets with hydrogen getter under high vacuum in the cryostat minimize heat loss into LH2 storage. All the components were carefully assembled in dust, oil and solvent-free environment with extra caution of vacuum tightness followed by dry nitrogen and helium purge. After initial cool-down of the cryocooler under vacuum, 99.999% of 300 K hydrogen gas was introduced to the liquefaction plant. From a series of liquefaction tests with or without LN2 precooling, the hydrogen liquefaction plant successfully demonstrated 1.4 L/h of hydrogen liquefaction with LN2 precooling and two o–p hydrogen converters, and 0.7 L/h without LN2 precooling.
Verifying computations without reexecuting them
Authors: Walfish Michael , Blumberg Andrew J.
Published: February 2015

From theoretical possibility to near practicality.
Automated support for diagnosis and repair
Authors: Alrajeh Dalal , Kramer Jeff , Russo Alessandra , Uchitel Sebastian
Published: February 2015

Model checking and logic-based learning together deliver automated support, especially in adaptive and autonomous systems.
Model-based testing
Authors: Binder Robert V. , Legeard Bruno , Kramer Anne
Published: February 2015

MBT has positive effects on efficiency and effectiveness, even if it only partially fulfills high expectations.
Three paradoxes of building platforms
Authors: Zeng Ming
Published: February 2015

Insights into creating China's Taobao online marketplace ecosystem.
Too big to fail
Authors: Neville-Neil George V.
Published: February 2015

Visibility leads to debuggability.
Cornell College
Authors: Sowell Ross
Published: February 2015

In addition to holding an Hour of Code at our student union on campus, we also connected with the local Mount Vernon Middle School. We helped organize and facilitate Hour Of Code events throughout the week so that each of the ~400 students in grades 5-8 at the middle school had the opportunity to try an Hour Of Code. At the end of the week, we held an after-school program where interested middle school students established their own computing club. This allows us to keep some of the momentum going from the Hour of Code. Students from our Cornell College ACM Student Chapter will continue to serve as mentors for students in the middle school computing club and work with them at events throughout the year.
Modeling of Sodium Tetrahydroborate Power System for Fuel Cell Vehicle
Authors: Tomoda Keisuke , Katayama Noboru , Hoshi Nobukazu , Yoshizaki Atsuhiro , Hirata Keiichi
Published: February 2015

The authors have proposed and made a hydrogen generation system for FCHV, which can generate large amount of hydrogen by hydrolysis of powdery sodium tetrahydroborate (NaBH4). Until now, it has been verified STEP system can generate hydrogen continuously with the average flow rate of 50 L/min and a polymer electrolyte fuel cell (PEFC) fueled by the hydrogen generated from the system can generate 5 kW of electric power. In addition, STEP system was installed to a prototype vehicle, and it was verified that the vehicle could drive. However, the required amount of the hydrogen to supply to the fuel cell widely varies according to the output power of the fuel cell. Moreover, it is difficult to control the amount of the hydrogen generated by STEP system because hydrolysis is chemical reaction. Thus, it is necessary to simulate the chemical reaction in STEP system under various conditions in order to investigate a pressure control scheme. Therefore, in this research, simulation models of hydrogen generation have been developed. In addition, in order to verify the effectiveness of the simulation models, analytical data obtained from the models are compared with experimental results.
Study on Hydrogen Crossover at Different Current Densities in Polymer Electrolyte Membrane Fuel Cells
Authors: Jung Aeri , Han Kookil , Hong Bo Ki , Kim Min Soo
Published: February 2015

The crossover is an inevitable phenomenon caused by the porosity of the membrane. Through this, not only protons, but also gases such as hydrogen, oxygen and nitrogen can permeate to opposite side and this causes the severe durability problem. Despite of this importance of crossover, there have been some limits in research. Therefore, much research has been conducted for an open circuit condition. For this reason, in this study, the hydrogen crossover rate under various current densities is experimentally measured for different relative humidity conditions. To detect hydrogen crossover rate, mass spectrometer is used in this experiment. With the mass spectrometer, the hydrogen crossover rate is measured and analyzed for different relative humidity conditions at various current densities.
Purification of Hydrogen Containing Carbon Dioxide Using Metal Hydride
Authors: Katayama Noboru , Dowaki K , Hayase M
Published: February 2015

In this work, the influence of carbon dioxide concentration in the hydrogen on metal hydride has been investigated. LmNi4.73Mn0.12Al0.15 was employed as a sample material for its durability against inorganic compound and operating temperature and pressure. Mixture of hydrogen and carbon dioxide is supplied to the sample in a double-ended cylinder at a constant flow rate and a part of the supplied gas is released to avoid condensing of impurity at a smaller constant flow rate than inlet. The temperature is maintained at 30 °C. The experimental results show the sample is able to absorb hydrogen selectively at carbon dioxide concentrations less than 30 vol% and the mixture of the carbon dioxide concentration of 20 vol% is purified to less than 0.1%.
Development of Thermal Insulation for Residential Fuel Cells System Elucidation of the Heat Transfer Mechanism in Insulation
Authors: Sugiura Kimihiko , Matoba Masahiro , Imae Yoshihiko , Imae Kenji
Published: February 2015

The fumed silica system insulation (CI) is widely adopted as thermal insulation of the residential fuel cells system called "ENE-FARM" in Japan because the insulation performance of 600°C or more is better than that of a conventional type. However, this fumed-silica system insulation is expensive because it puts out a lot of useless materials by the machining process. We aims to reduce the cost of insulation by which the insulation use an aerogel as main material, and be made by a filtered water metal mold forming method. This paper aims to elucidate the heat transfer mechanism of the newly developed insulation (NDI) and decide the optimum infrared reflection material and the additive rate, and finally propose the optimum density of the NDI. As a result, the NDI obtained the performance similar to the CI by adding 15%-25% of SiC as an infrared reflection material. The main of heat transfer of the NDI is thermal conduction.
Electrochemical Heat Engines
Authors: Gemmen Randall , Williams Mark Christopher , Richards George
Published: February 2015

This brief thermodynamic analysis theoretically explores the potential of using a solid-state electrochemical heat engine (EHE) to continually harvest waste heat from available thermal energy from natural and man-made sources. These EHE systems are composed of a fuel cell hybrid (FCH) and an electrolyer hybrid (EH) which is composed of fuel cells and heat engines, and electrolysers and heat engines, respectively. These systems electrochemically utilize reversible working reactions (WR) in a manner to produce electrical energy from thermal energy. Ultimately, EHE’s in this paper exploit the change in basic thermodynamic properties with temperature. This development introduces the thermodynamic methodology for analyzing and combining EHE’s.
Performance Envelope for Electrolyser Systems
Authors: Winkler Wolfgang , Suzuki Ai , Miyamoto Akira , Yokokawa Harumi , Williams Mark C
Published: February 2015

The performance envelope for an electrolyser system is developed and explored. The reversible HT- and NT-electrolyser performance can be described using reversible thermodynamics. The benefits of using the high temperature (HT) electrolyser are discussed. If we simplify the reversible process by replacing the reversible heat engines with a heat exchanger assembly we identify a demand of additional heat for evaporation if using a HTelectrolyzer by considering the system integration while NT-electrolyzer use electric work for supplying needed reaction heat.
Altered metabolism and resistance to obesity in long-lived mice producing reduced levels of IGF-I
Authors: Salmon Adam B. , Lerner Chad , Ikeno Yuji , Motch Perrine Susan M. , McCarter Roger , Sell Christian
Published: February 2015

The extension of lifespan due to reduced insulin-like growth factor 1 (IGF-I) signaling in mice has been proposed to be mediated through alterations in metabolism. Previously, we showed that mice homozygous for an insertion in the Igf1 allele have reduced levels of IGF-I, are smaller, and have an extension of maximum lifespan. Here, we tested whether this specific reduction of IGF-I alters glucose metabolism both on normal rodent chow and in response to high-fat feeding. We found that female IGF-I-deficient mice were lean on a standard rodent diet but paradoxically displayed an insulin-resistant phenotype. However, these mice gained significantly less weight than normal controls when placed on a high-fat diet. In control animals, insulin response was significantly impaired by high-fat feeding, whereas IGF-I-deficient mice showed a much smaller shift in insulin response after high-fat feeding. Gluconeogenesis was also elevated in the IGF-I-deficient mice relative to controls on both normal and high-fat diet. An analysis of metabolism and respiratory quotient over 24 h indicated that the IGF-I-deficient mice preferentially utilized fatty acids as an energy source when placed on a high-fat diet. These results indicate that reduction in the circulating and tissue IGF-I levels can produce a metabolic phenotype in female mice that increases peripheral insulin resistance but renders animals resistant to the deleterious effects of high-fat feeding.
Ameliorating Effects of Ethanol Extract ofFructus mumeon Scopolamine-Induced Memory Impairment in Mice
Authors: Kim Min-Soo , Jeon Won Kyung , Lee Kye Wan , Park Yu Hwa , Han Jung-Soo
Published: February 2015

We previously reported thatFructus mume(F. mume) extract shows protective effects on memory impairments and anti-inflammatory effects induced by chronic cerebral hypoperfusion. Neurodegeneration of basal cholinergic neurons is also observed in the brain with chronic cerebral hypoperfusion. Therefore, the present study was conducted to examine whetherF. mumeextracts enhance cognitive function via the action of cholinergic neuron using a scopolamine-induced animal model of memory impairments.F. mume(50, 100, or 200 mg/kg) was administered to C57BL/6 mice for 14 days (days 1–14) and memory impairment was induced by scopolamine (1 mg/kg), a muscarinic receptor antagonist for 7 days (days 8–14). Spatial memory was assessed using Morris water maze and hippocampal level of acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) was examined by ELISA and immunoblotting. Mice that received scopolamine alone showed impairments in acquisition and retention in Morris water maze task and increased activity of AChE in the hippocampus. Mice that receivedF. mumeand scopolamine showed no scopolamine-induced memory impairment and increased activity of AChE. In addition, treatments ofF. mumeincreased ChAT expression in the hippocampus. These results indicated thatF. mumemight enhance cognitive function via action of cholinergic neurons.
A Brief Analysis of Suicide Methods and Trends in Virginia from 2003 to 2012
Authors: Hassamal Sameer , Keyser-Marcus Lori , Crouse Breden Ericka , Hobron Kathrin , Bhattachan Atit , Pandurangi Ananda
Published: February 2015

Background.The objective is to analyze and compare Virginia suicide data from 2003 to 2012 to US suicide data.Methods.Suicide trends by method, age, gender, and race were obtained from Virginia’s Office of the Chief Medical Examiner’s annual reports.Results.Similar to US suicide rates, suicide rates in Virginia increased between 2003 and 2012 from 10.9/100,000 people to 12.9/100,000 people. The most common methods were firearm, asphyxia, and intentional drug overdose, respectively. The increase in asphyxia (r=0.77,P≤0.01) and decrease in CO poisoning (r=-0.89,P≤0.01) were significant. Unlike national trends, intentional drug overdoses decreased (r=-0.55,P=0.10). Handgun suicides increased (r=0.61,P=0.06) and are the most common method of firearm suicide. Hanging was the most common method of asphyxia. Helium suicides also increased (r=0.75,P=0.05). Middle age females and males comprise the largest percentage of suicide. Unlike national data, the increase in middle age male suicides occurred only in the 55–64-year-old age group (r=0.79,P≤0.01) and decreased in the 35–44-year-old age group (r=-0.60,P=0.07) and 10–14-year-old age group (r=-0.73,P=0.02). Suicide in all female age ranges remained stable. Caucasians represent the highest percentage of suicide.Conclusion.There has been a rise in suicide in Virginia and suicide rates and trends have closely resembled the national average albeit some differences. Suicide prevention needs to be enhanced.
A Novel Execution Mode Selection Scheme for Wireless Computing
Authors: Chen Jiadi , Wang Wenbo
Published: February 2015

Computation offloading is an effective way to alleviate the resource limited problem of mobile devices. However, the offloading is not an always advantageous strategy for under some circumstances the overhead in time and energy may turn out to be greater than the offloading savings. Therefore, an offloading decision scheme is in demand for mobile devices to decide whether to offload a computation task to the server or to execute it in a local processor. In this paper, the offloading decision problem is translated into a dynamic execution mode selection problem, the objective of which is to minimize the task execution delay and reduce the energy consumption of mobile devices. A novel execution mode adjustment mechanism is introduced to make the execution process more flexible for real-time environment variation. Numerical results indicate that the proposed scheme can significantly reduce the task execution delay in an energy-efficient way.
Non-Hodgkin Lymphoma in Children with Primary Immunodeficiencies: Clinical Manifestations, Diagnosis, and Management, Belarusian Experience
Authors: Fedorova Alina , Sharapova Svetlana , Mikhalevskaya Taisia , Aleshkevich Svetlana , Proleskovskaya Inna , Stsegantseva Maria , Belevtsev Mikhail , Aleinikova Olga
Published: February 2015

Introduction. Non-Hodgkin lymphoma (NHL) is the most frequent malignancy associated with primary immune deficiency disease (PID). We aimed to present the clinical characteristics and outcomes of Belarusian children with PID who developed NHL. Procedure. We reviewed 16 patients with PID and NHL. Eight patients had combined PID: 5—Nijmegen breakage syndrome, 1—Bloom syndrome, 1—Wiskott-Aldrich syndrome, and 1—Х-linked lymphoproliferative syndrome. Results. In 75% cases PID was diagnosed simultaneously or after the NHL was confirmed. PID-associated NHL accounted for 5.7% of all NHL and was characterized by younger median age (6.3 versus 10.0 years, P<0.05) and by prevalence of large-cell types (68.8% versus 24.5%, P<0.001). Children with combined PID had median age of 1.3 years; 5 of them developed EBV-associated diffuse large B-cell lymphoma with lung involvement. Five of 6 patients with chromosomal breakage syndrome developed T-NHL. Six patients died of infections; two died after tumor progression; one child had early relapse; two died of second NHL and one of secondary hemophagocytic syndrome. Overall, 4 children are alive and disease-free after a follow-up from 1.4 to 5.7 years. Conclusions. PID needs to be diagnosed early. Individualized chemotherapy, comprehensive supportive treatment, and hematopoietic stem cell transplantation may improve survival of children with PID and NHL.
Influence of Thermal Treatment on Mechanical and Morphological Characteristics of Polyamide 11/Cellulose Nanofiber Nanocomposites
Authors: Panaitescu Denis Mihaela , Gabor Raluca Augusta , Frone Adriana Nicoleta , Vasile Eugeniu
Published: February 2015

Nanocomposite films were prepared from polyamide 11 (PA11) and cellulose nanofibers (CN) by melt compounding and compression molding. The impact of thermal treatment on the morphology and mechanical behavior of PA11 and nanocomposite films was studied using dynamic mechanical analysis, tensile tests, X‐ray diffraction (XRD), and peak force (PF) QNM technique. Slightly higher storage modulus values were obtained for nanocomposites compared to the matrix before the treatment, but a noticeable increase was observed after the treatment. Although CN addition determined increased tensile strength and modulus both before and after the treatment, the increase was much more significant in the case of treated films. The best mechanical properties were shown by treated PA11 films containing 5 wt% CN, with 40% higher Young’s modulus and with 35% higher tensile strength compared to the matrix. Some of the changes pointed out by static and dynamic mechanical tests were explained by the morphological changes determined by the thermal treatment and emphasized by PF QNM and by the increase of XRD crystallinity. A transition from lamellar stack morphology to one involving spherulites was highlighted by AFM. Thermal treatment has proved a valuable method for improving the mechanical properties of PA11/CN composites.