bluuebunny/crossref_metadata_2025 huggingface dataset:
Oblique reconstructions in tomosynthesis. II. Super‐resolution
Authors: Acciavatti Raymond J. , Maidment Andrew D. A.
Published: October 2013

Purpose:

In tomosynthesis, super‐resolution has been demonstrated using reconstruction planes parallel to the detector. Super‐resolution allows for subpixel resolution relative to the detector. The purpose of this work is to develop an analytical model that generalizes super‐resolution to oblique reconstruction planes.

Methods:

In a digital tomosynthesis system, a sinusoidal test object is modeled along oblique angles (i.e., “pitches”) relative to the plane of the detector in a 3D divergent‐beam acquisition geometry. To investigate the potential for super‐resolution, the input frequency is specified to be greater than the alias frequency of the detector. Reconstructions are evaluated in an oblique plane along the extent of the object using simple backprojection (SBP) and filtered backprojection (FBP). By comparing the amplitude of the reconstruction against the attenuation coefficient of the object at various frequencies, the modulation transfer function (MTF) is calculated to determine whether modulation is within detectable limits for super‐resolution. For experimental validation of super‐resolution, a goniometry stand was used to orient a bar pattern phantom along various pitches relative to the breast support in a commercial digital breast tomosynthesis system.

Results:

Using theoretical modeling, it is shown that a single projection image cannot resolve a sine input whose frequency exceeds the detector alias frequency. The high frequency input is correctly visualized in SBP or FBP reconstruction using a slice along the pitch of the object. The Fourier transform of this reconstructed slice is maximized at the input frequency as proof that the object is resolved. Consistent with the theoretical results, experimental images of a bar pattern phantom showed super‐resolution in oblique reconstructions. At various pitches, the highest frequency with detectable modulation was determined by visual inspection of the bar patterns. The dependency of the highest detectable frequency on pitch followed the same trend as the analytical model. It was demonstrated that super‐resolution is not achievable if the pitch of the object approaches 90°, corresponding to the case in which the test frequency is perpendicular to the breast support. Only low frequency objects are detectable at pitches close to 90°.

Conclusions:

This work provides a platform for investigating super‐resolution in oblique reconstructions for tomosynthesis. In breast imaging, this study should have applications in visualizing microcalcifications and other subtle signs of cancer.
Direct water and fat determination in two‐point Dixon imaging with flexible echo times
Authors: Rambow Olen , Hazle John , Clark John , Ma Jingfei
Published: October 2013

Purpose:

Identifying water and fat unambiguously in multipoint Dixon imaging often requires phase correction, which can be challenging and may fail. The purpose of this work is to present a geometric interpretation of the two‐point Dixon method with flexible echo times (TEs) and to investigate the conditions under which water and fat can be determined directly without phase correction.

Methods:

Geometrically, the equation for the magnitude of the acquired signal at a givenTE represents an ellipse in the water–fat plane centered at the origin. Determining water and fat in two‐point Dixon imaging thus amounts to finding the correct intercept between two ellipses from the signals at two TEs. At the right TE combinations, the physicality requirement that water and fat be non‐negative can be used to select a unique water and fat solution. Systematic computer simulations were conducted to examine the ranges of the TEs for which this approach is feasible and how different noise levels impact the feasibility. Phantom and in vivo experiments on a 1.5‐T whole‐body MRI scanner were used to validate the computer simulations.

Results:

In simulation and phantom experiments, nearly all pixels of pure water or pure fat were reliably identified based on the physicality requirement alone for a range of practically usefulTE combinations (e.g., around 3 ms/6 ms at 1.5 T) and at moderate to high SNR levels (≥25). At other TE combinations, finding the correct solution based on the physicality requirement alone was not feasible or became sensitive to noise. In vivo findings were in overall agreement with the simulation and phantom studies, although the percentage of pixels that were correctly determined was lower.

Conclusions:

The problem of direct water and fat determination without phase correction can be understood geometrically. Using the physicality requirement, it is possible to identify the differentTE combinations and imaging conditions under which water and fat imaging can be performed either completely without phase correction or by generating a first‐pass solution that can be used to improve the processing reliability of a phase‐correction based method.
Comparison of across-frequency integration strategies in a binaural detection model
Authors: Breebaart Jeroen
Published: October 2013

Breebaart et al. [J. Acoust. Soc. Am. 110, 1089–1104 (2001)] reported that the masker bandwidth dependence of detection thresholds for an out-of-phase signal and an in-phase noise masker (N0Sπ) can be explained by principles of integration of information across critical bands. In this paper, different methods for such across-frequency integration process are evaluated as a function of the bandwidth and notch width of the masker. The results indicate that an “optimal detector” model assuming independent internal noise in each critical band provides a better fit to experimental data than a best filter or a simple across-frequency integrator model. Furthermore, the exponent used to model peripheral compression influences the accuracy of predictions in notched conditions.
Rapid Detection and Identification of Nontuberculous Mycobacterial Pathogens in Fish by Using High-Resolution Melting Analysis
Authors: Phung Thu Nguyet , Caruso Domenico , Godreuil Sylvain , Keck Nicolas , Vallaeys Tatiana , Avarre Jean-Christophe
Published: October 2013

Mycobacterial infections in fish are commonly referred to as piscine mycobacteriosis, irrespectively of the specific identity of the causal organism. They usually cause a chronic disease and sometimes may result in high mortalities and severe economic losses. Nearly 20 species of
Mycobacterium
have been reported to infect fish. Among them,
Mycobacterium marinum
,
M. fortuitum
, and
M. chelonae
are generally considered the major agents responsible for fish mycobacteriosis. As no quick and inexpensive diagnostic test exists, we tested the potential of high-resolution melting analysis (HRMA) to rapidly identify and differentiate several
Mycobacterium
species involved in fish infections. By analyzing both the melting temperature and melting profile of the 16S-23S rRNA internal transcribed spacer (ITS), we were able to discriminate 12 different species simultaneously. Sensitivity tests conducted on purified
M. marinum
and
M. fortuitum
DNA revealed a limit of detection of 10 genome equivalents per reaction. The primers used in this procedure did not lead to any amplification signal with 16 control non-
Mycobacterium
species, thereby demonstrating their specificity for the genus
Mycobacterium
.
Characterization of Bacteriophages Cp1 and Cp2, the Strain-Typing Agents for Xanthomonas axonopodis pv. citri
Authors: Ahmad Abdelmonim Ali , Ogawa Megumi , Kawasaki Takeru , Fujie Makoto , Yamada Takashi
Published: October 2013

The strains of
Xanthomonas axonopodis
pv. citri, the causative agent of citrus canker, are historically classified based on bacteriophage (phage) sensitivity. Nearly all
X. axonopodis
pv. citri strains isolated from different regions in Japan are lysed by either phage Cp1 or Cp2; Cp1-sensitive (Cp1
s
) strains have been observed to be resistant to Cp2 (Cp2
r
) and
vice versa
. In this study, genomic and molecular characterization was performed for the typing agents Cp1 and Cp2. Morphologically, Cp1 belongs to the
Siphoviridae
. Genomic analysis revealed that its genome comprises 43,870-bp double-stranded DNA (dsDNA), with 10-bp 3′-extruding cohesive ends, and contains 48 open reading frames. The genomic organization was similar to that of
Xanthomonas
phage phiL7, but it lacked a group I intron in the DNA polymerase gene. Cp2 resembles morphologically
Escherichia coli
T7-like phages of
Podoviridae
. The 42,963-bp linear dsDNA genome of Cp2 contained terminal repeats. The Cp2 genomic sequence has 40 open reading frames, many of which did not show detectable homologs in the current databases. By proteomic analysis, a gene cluster encoding structural proteins corresponding to the class III module of T7-like phages was identified on the Cp2 genome. Therefore, Cp1 and Cp2 were found to belong to completely different virus groups. In addition, we found that Cp1 and Cp2 use different molecules on the host cell surface as phage receptors and that host selection of
X. axonopodis
pv. citri strains by Cp1 and Cp2 is not determined at the initial stage by binding to receptors.
The Novel BacterialN-Demethylase PdmAB Is Responsible for the Initial Step ofN,N-Dimethyl-Substituted Phenylurea Herbicide Degradation
Authors: Gu Tao , Zhou Chaoyang , Sørensen Sebastian R. , Zhang Ji , He Jian , Yu Peiwen , Yan Xin , Li Shunpeng
Published: October 2013

The environmental fate of phenylurea herbicides has received considerable attention in recent decades. The microbial metabolism ofN,N-dimethyl-substituted phenylurea herbicides can generally be initiated by mono-N-demethylation. In this study, the molecular basis for this process was revealed. ThepdmABgenes inSphingobiumsp. strain YBL2 were shown to be responsible for the initial mono-N-demethylation of commonly usedN,N-dimethyl-substituted phenylurea herbicides. PdmAB is the oxygenase component of a bacterial Rieske non-heme iron oxygenase (RO) system. The genespdmAB, encoding the α subunit PdmA and the β subunit PdmB, are organized in a transposable element flanked by two direct repeats of an insertion element resembling ISRh1. Furthermore, this transposable element is highly conserved among phenylurea herbicide-degrading sphingomonads originating from different areas of the world. However, there was no evidence of a gene for an electron carrier (a ferredoxin or a reductase) located in the immediate vicinity ofpdmAB. Without its cognate electron transport components, expression of PdmAB inEscherichia coli,Pseudomonas putida, and other sphingomonads resulted in a functional enzyme. Moreover, coexpression of a putative [3Fe-4S]-type ferredoxin fromSphingomonassp. strain RW1 greatly enhanced the catalytic activity of PdmAB inE. coli. These data suggested that PdmAB has a low specificity for electron transport components and that its optimal ferredoxin may be the [3Fe-4S] type. PdmA exhibited low homology to the α subunits of previously characterized ROs (less than 37% identity) and did not cluster with the RO group involved inO- orN-demethylation reactions, indicating that PdmAB is a distinct bacterial RON-demethylase.
A Novel Gene Involved in the Survival of Streptococcus mutans under Stress Conditions
Authors: Li Dan , Shibata Yukie , Takeshita Toru , Yamashita Yoshihisa
Published: October 2013

A
Streptococcus mutans
mutant defective in aciduricity was constructed by random-insertion mutagenesis. Sequence analysis of the mutant revealed a mutation in
gidA
, which is known to be involved in tRNA modification in
Streptococcus pyogenes
. Complementation of
gidA
by
S. pyogenes
gidA
recovered the acid tolerance of
S. mutans
. Although the
gidA
-inactivated
S. pyogenes
mutant exhibited significantly reduced expression of multiple extracellular virulence proteins, the
S. mutans
mutant did not. On the other hand, the
gidA
mutant of
S. mutans
showed reduced ability to withstand exposure to other stress conditions (high osmotic pressure, high temperature, and bacitracin stress) besides an acidic environment. In addition, loss of GidA decreased the capacity for glucose-dependent biofilm formation by over 50%. This study revealed that
gidA
plays critical roles in the survival of
S. mutans
under stress conditions, including lower pH.
Genomic Overview and Biological Functions of Exopolysaccharide Biosynthesis in Bifidobacterium spp
Authors: Hidalgo-Cantabrana Claudio , Sánchez Borja , Milani Christian , Ventura Marco , Margolles Abelardo , Ruas-Madiedo Patricia
Published: October 2013

For many years, bacterial exopolysaccharides (EPS) have received considerable scientific attention, mainly due to their contribution to biofilm formation and, above all, because EPS are potential virulence factors. In recent times, interest in EPS research has enjoyed a welcome boost thanks to the discovery of their ability to mediate communication processes with their surrounding environment and to their contribution to host health maintenance. In this review, we provide a fresh perspective on the genetics and activity of these polymers in members of the
Bifidobacterium
genus, a common gut inhabitant of humans and animals that has been associated with several health-promoting effects. Bifidobacteria can use EPS to protect themselves against the harsh conditions of the gastrointestinal tract, thus improving their persistence in the host. Indeed, the relevant function of EPS for bifidobacteria is underlined by the fact that most genomes sequenced until now contain genes related to EPS biosynthesis. A high interspecies variability in the number of genes and structural organization is denoted among species/subspecies; thus,
eps
clusters in this genus do not display a consensus genetic architecture. Their different G+C content compared to that of the whole genome suggests that
eps
genes have been acquired by horizontal transfer. From the host perspective, EPS-producing bifidobacteria are able to trigger both innate and adaptive immune responses, and they are able to modulate the composition and activity of the gut microbiota. Thus, these polymers seem to be critical in understanding the physiology of bifidobacteria and their interaction with the host.
Interaction between the Microbial Community and Invading Escherichia coli O157:H7 in Soils from Vegetable Fields
Authors: Yao Zhiyuan , Wang Haizhen , Wu Laosheng , Wu Jianjun , Brookes Philip C. , Xu Jianming
Published: October 2013

The survival of
Escherichia coli
O157:H7 in soils can contaminate vegetables, fruits, drinking water, etc. However, data on the impact of
E. coli
O157:H7 on soil microbial communities are limited. In this study, we monitored the changes in the indigenous microbial community by using the phospholipid fatty acid (PLFA) method to investigate the interaction of the soil microbial community with
E. coli
O157:H7 in soils. Simple correlation analysis showed that the survival of
E. coli
O157:H7 in the test soils was negatively correlated with the ratio of Gram-negative (G
−
) to Gram-positive (G
+
) bacterial PLFAs (G
−
/G
+
ratio). In particular, levels of 14 PLFAs were negatively correlated with the survival time of
E. coli
O157:H7. The contents of actinomycetous and fungal PLFAs in the test soils declined significantly (
P
, <0.05) after 25 days of incubation with
E. coli
O157:H7. The G
−
/G
+
ratio declined slightly, while the ratio of bacterial to fungal PLFAs (B/F ratio) and the ratio of normal saturated PLFAs to monounsaturated PLFAs (S/M ratio) increased, after
E. coli
O157:H7 inoculation. Principal component analysis results further indicated that invasion by
E. coli
O157:H7 had some effects on the soil microbial community. Our data revealed that the toxicity of
E. coli
O157:H7 presents not only in its pathogenicity but also in its effect on soil microecology. Hence, close attention should be paid to the survival of
E. coli
O157:H7 and its potential for contaminating soils.
Contributions of Aspergillus fumigatus ATP-Binding Cassette Transporter Proteins to Drug Resistance and Virulence
Authors: Paul Sanjoy , Diekema Daniel , Moye-Rowley W. Scott
Published: October 2013

In yeast cells such as those of
Saccharomyces cerevisiae
, expression of ATP-binding cassette (ABC) transporter proteins has been found to be increased and correlates with a concomitant elevation in azole drug resistance. In this study, we investigated the roles of two
Aspergillus fumigatus
proteins that share high sequence similarity with
S. cerevisiae
Pdr5, an ABC transporter protein that is commonly overproduced in azole-resistant isolates in this yeast. The two
A. fumigatus
genes encoding the ABC transporters sharing the highest sequence similarity to
S. cerevisiae
Pdr5 are called
abcA
and
abcB
here. We constructed deletion alleles of these two different ABC transporter-encoding genes in three different strains of
A. fumigatus
. Loss of
abcB
invariably elicited increased azole susceptibility, while
abcA
disruption alleles had variable phenotypes. Specific antibodies were raised to both AbcA and AbcB proteins. These antisera allowed detection of AbcB in wild-type cells, while AbcA could be visualized only when overproduced from the
hspA
promoter in
A. fumigatus
. Overproduction of AbcA also yielded increased azole resistance. Green fluorescent protein fusions were used to provide evidence that both AbcA and AbcB are localized to the plasma membrane in
A. fumigatus
. Promoter fusions to firefly luciferase suggested that expression of both ABC transporter-encoding genes is inducible by azole challenge. Virulence assays implicated AbcB as a possible factor required for normal pathogenesis. This work provides important new insights into the physiological roles of ABC transporters in this major fungal pathogen.
Laccases Involved in 1,8-Dihydroxynaphthalene Melanin Biosynthesis in Aspergillus fumigatus Are Regulated by Developmental Factors and Copper Homeostasis
Authors: Upadhyay Srijana , Torres Guadalupe , Lin Xiaorong
Published: October 2013

Aspergillus fumigatus
produces heavily melanized infectious conidia. The conidial melanin is associated with fungal virulence and resistance to various environmental stresses. This 1,8-dihydroxynaphthalene (DHN) melanin is synthesized by enzymes encoded in a gene cluster in
A. fumigatus
, including two laccases, Abr1 and Abr2. Although this gene cluster is not conserved in all aspergilli, laccases are critical for melanization in all species examined. Here we show that the expression of
A. fumigatus
laccases Abr1/2 is upregulated upon hyphal competency and drastically increased during conidiation. The Abr1 protein is localized at the surface of stalks and conidiophores, but not in young hyphae, consistent with the gene expression pattern and its predicted role. The induction of Abr1/2 upon hyphal competency is controlled by BrlA, the master regulator of conidiophore development, and is responsive to the copper level in the medium. We identified a developmentally regulated putative copper transporter, CtpA, and found that CtpA is critical for conidial melanization under copper-limiting conditions. Accordingly, disruption of CtpA enhanced the induction of
abr1
and
abr2
, a response similar to that induced by copper starvation. Furthermore, nonpigmented
ctpA
Δ conidia elicited much stronger immune responses from the infected invertebrate host
Galleria mellonella
than the pigmented
ctpA
Δ or wild-type conidia. Such enhancement in eliciting
Galleria
immune responses was independent of the
ctpA
Δ conidial viability, as previously observed for the DHN melanin mutants. Taken together, our findings indicate that both copper homeostasis and developmental regulators control melanin biosynthesis, which affects conidial surface properties that shape the interaction between this pathogen and its host.
Lactobacillus reuteri-Specific Immunoregulatory Gene
rsiR
Modulates Histamine Production and Immunomodulation by Lactobacillus reuteri
Authors: Hemarajata P. , Gao C. , Pflughoeft K. J. , Thomas C. M. , Saulnier D. M. , Spinler J. K. , Versalovic J.
Published: October 2013

Human microbiome-derived strains of
Lactobacillus reuteri
potently suppress proinflammatory cytokines like human tumor necrosis factor (TNF) by converting the amino acid
l
-histidine to the biogenic amine histamine. Histamine suppresses mitogen-activated protein (MAP) kinase activation and cytokine production by signaling via histamine receptor type 2 (H
2
) on myeloid cells. Investigations of the gene expression profiles of immunomodulatory
L. reuteri
ATCC PTA 6475 highlighted numerous genes that were highly expressed during the stationary phase of growth, when TNF suppression is most potent. One such gene was found to be a regulator of genes involved in histidine-histamine metabolism by this probiotic species. During the course of these studies, this gene was renamed the
Lactobacillus reuteri
-specific immunoregulatory (
rsiR
) gene. The
rsiR
gene is essential for human TNF suppression by
L. reuteri
and expression of the histidine decarboxylase (
hdc
) gene cluster on the
L. reuteri
chromosome. Inactivation of
rsiR
resulted in diminished TNF suppression
in vitro
and reduced anti-inflammatory effects
in vivo
in a trinitrobenzene sulfonic acid (TNBS)-induced mouse model of acute colitis. A
L. reuteri
strain lacking an intact
rsiR
gene was unable to suppress colitis and resulted in greater concentrations of serum amyloid A (SAA) in the bloodstream of affected animals. The P

hdcAB

promoter region targeted by
rsiR
was defined by reporter gene experiments. These studies support the presence of a regulatory gene,
rsiR
, which modulates the expression of a gene cluster known to mediate immunoregulation by probiotics at the transcriptional level. These findings may point the way toward new strategies for controlling gene expression in probiotics by dietary interventions or microbiome manipulation.
Structure and Function of a Novel
ld
-Carboxypeptidase A Involved in Peptidoglycan Recycling
Authors: Das Debanu , Hervé Mireille , Elsliger Marc-André , Kadam Rameshwar U. , Grant Joanna C. , Chiu Hsiu-Ju , Knuth Mark W. , Klock Heath E. , Miller Mitchell D. , Godzik Adam , Lesley Scott A. , Deacon Ashley M. , Mengin-Lecreulx Dominique , Wilson Ian A.
Published: October 2013

Approximately 50% of cell wall peptidoglycan in Gram-negative bacteria is recycled with each generation. The primary substrates used for peptidoglycan biosynthesis and recycling in the cytoplasm are GlcNAc-MurNAc(anhydro)-tetrapeptide and its degradation product, the free tetrapeptide. This complex process involves ∼15 proteins, among which the cytoplasmic enzyme
ld
-carboxypeptidase A (LdcA) catabolizes the bond between the last two
l
- and
d
-amino acid residues in the tetrapeptide to form the tripeptide, which is then utilized as a substrate by murein peptide ligase (Mpl). LdcA has been proposed as an antibacterial target. The crystal structure of
Novosphingobium aromaticivorans
DSM 12444 LdcA (
Na
LdcA) was determined at 1.89-Å resolution. The enzyme was biochemically characterized and its interactions with the substrate modeled, identifying residues potentially involved in substrate binding. Unaccounted electron density at the dimer interface in the crystal suggested a potential site for disrupting protein-protein interactions should a dimer be required to perform its function in bacteria. Our analysis extends the identification of functional residues to several other homologs, which include enzymes from bacteria that are involved in hydrocarbon degradation and destruction of coral reefs. The
Na
LdcA crystal structure provides an alternate system for investigating the structure-function relationships of LdcA and increases the structural coverage of the protagonists in bacterial cell wall recycling.
What helps children to move more at school recess and lunchtime? Mid-intervention results from Transform-Us! cluster-randomised controlled trial
Authors: Yıldırım Mine , Arundell Lauren , Cerin Ester , Carson Valerie , Brown Helen , Crawford David , Hesketh Kylie D , Ridgers Nicola D , Te Velde Saskia J , Chinapaw Mai J M , Salmon Jo
Published: October 2013

Background

To investigate the interpersonal and physical environment mediators of the Transform-Us! mid-intervention effects on physical activity (PA) during recess and lunchtime.

Methods

Transform-Us! is a clustered randomised school-based intervention with four groups: sedentary behaviour intervention (SB-I), PA intervention (PA-I), combined PA+SB-I and control group. All children in grade 3 from 20 participating primary schools in Melbourne, Australia were eligible to complete annual evaluation assessments. The outcomes were the proportion of time spent in moderate-to-vigorous PA (MVPA) and light PA (LPA) during recess and lunchtime assessed by accelerometers. Potential mediators included: perceived social support from teachers; perceived availability of line markings; perceived accessibility of sports equipment; and perceived school play environment. Generalised linear models were used and mediation effects were estimated by product-of-coefficients (a·b) approach.

Results

268 children (8.2 years, 57% girls at baseline) provided complete data at both time points. A significant intervention effect on MVPA during recess in the SB-I and PA-I groups compared with the control group (proportional difference in MVPA time; 38% (95% CI 21% to 57%) and 40% (95% CI 20% to 62%), respectively) was found. The perceived school play environment was significantly positively associated with MVPA at recess among girls. An increase in perceived social support from teachers suppressed the PA+SB-I effect on light PA during recess (a·b= −0.03, 95% CI −0.06 to −0.00). No significant mediating effects on PA during recess and lunchtime were observed.

Conclusions

A positive perception of the school play environment was associated with higher MVPA during recess among girls. Future studies should conduct mediation analyses to explore underlying mechanisms of PA interventions.
‘Not another safety culture survey’: using the Canadian patient safety climate survey (Can-PSCS) to measure provider perceptions of PSC across health settings
Authors: Ginsburg Liane R , Tregunno Deborah , Norton Peter G , Mitchell Jonathan I , Howley Heather
Published: October 2013

Background

The importance of a strong safety culture for enhancing patient safety has been stated for over a decade in healthcare. However, this complex construct continues to face definitional and measurement challenges. Continuing improvements in the measurement of this construct are necessary for enhancing the utility of patient safety climate surveys (PSCS) in research and in practice. This study examines the revised Canadian PSCS (Can-PSCS) for use across a range of care settings.

Methods

Confirmatory factor analytical approaches are used to extensively test the Can-PSCS. Initial and cross-validation samples include 13 126 and 6324 direct care providers from 119 and 35 health settings across Canada, respectively.

Results

Results support a parsimonious model of direct care provider perceptions of patient safety climate (PSC) with 19 items in six dimensions: (1) organisational leadership support for safety; (2) incident follow-up; (3) supervisory leadership for safety; (4) unit learning culture; (5) enabling open communication I: judgement-free environment; (6) enabling open communication II: job repercussions of error. Results also support the validity of the Can-PSCS across a range of care settings.

Conclusions

The Can-PSCS has several advantages: (1) it is a theory-based instrument with a small number of actionable dimensions central to the construct of PSC; (2) it has robust psychometric properties; (3) it is validated for use across a range of care settings, therefore suitable for use in regionalised health delivery systems and can help to raise expectations about acceptable levels of PSC across the system; (4) it has been tested in a publicly funded universal health insurance system and may be suitable for similar international systems.
The ‘who are all these people?’ study
Authors: Gilligan Peadar , Joseph Danny , Bartlett Matthew , Morris Aoife , Mahajan Ajay , McHugh Karen , Hillary Fiona , O'Kelly Patrick
Published: October 2013

Background

Overcrowding of emergency departments (EDs) adversely affects the delivery of emergency care and results in increased patient mortality.

Objective and methods

To examine what contributes to the ED crowd and to specifically examine the patient associated population. The ED in which the research was performed is consistently one of the most overcrowded in Ireland.

Results

On average 66.7% of the patients in the ED during the study period were boarded awaiting a hospital bed following full processing by the ED staff and agreement by the on-call team that admission was required. The most overcrowded part of the department was the majors area. In this area 55.5% of those present were patients, visitors accounted for 16.6% of occupants, nursing staff 11%, on-call teams 7% and the ED doctors 6.3%.

Conclusions

Knowing who the people in the crowd are helps to guide management decisions about how the crowd might be reduced. Our department now has a strict accompanying person/visitor policy that limits the number of visitors to patients and limits visiting times for those relatives with a patient who is experiencing a prolonged stay in the ED.
No gender-related bias in acute musculoskeletal pain management in the emergency department
Authors: Uri Ofir , Elias Shlomo , Behrbalk Eyal , Halpern Pinchas
Published: October 2013

Introduction

Patients’ gender remains a contributor for bias in pain management. Implementation of standardised analgesic protocols has been shown to minimise bias in analgesic care. The purpose of this study was to assess whether gender-related bias in pain management exists in our emergency department (ED) setting, where a standardised pain management protocol based on patients’ subjective pain rating is routinely used.

Methods

Pain management measures (ie, analgesia administration, waiting time for analgesia, pain relief and patients’ satisfaction) were prospectively assessed in 328 patients (150 women and 178 men, average age 36±18 years) who were treated in our ED for acute musculoskeletal pain.

Results

Patients’ subjective pain rating on arrival were similar for men and women (59±24 mm vs 61±26 mm, respectively; p=0.47). Interestingly, physicians using the same scale assessed the women's pain level to be higher than that of men (75±25 mm vs 63±22 mm, respectively; p<0.001) and higher than that of women's subjective pain rating (75±25 mm vs 61±26 mm respectively; p<0.001). Nevertheless, the rates of analgesia administration, waiting time for analgesia, pain relief and patient satisfaction were similar for both genders. Physicians’ own gender did not affect analgesic care.

Conclusions

Our findings suggest that a standardised pain management protocol based on patients’ subjective pain rating may reduce gender-related bias in acute musculoskeletal pain management.
The association between on-scene blood pressure and early neurological deterioration in patients with spontaneous intracerebral haemorrhage
Authors: Fan Ju-Sing , Chen Yen-Chia , Huang Hsien-Hao , How Chorng-Kuang , Yen David Hung-Tsang , Huang Mu-Shun
Published: October 2013

Objective

To determine whether on-scene BP is associated with early neurological deterioration (END) in patients with spontaneous intracerebral haemorrhage (SICH).

Methods

This retrospective cohort study enrolled consecutive ambulance-transported adult SICH patients treated at our emergency department (ED) from January 2007 through December 2012. END was defined as a ≥2-point decrease in GCS within 24 h of ED arrival. The exact relationship between on-scene BP and END was assessed using multiple logistic regression analyses for adjusting age, gender, Charlson Index, aspirin use, smoking, elapsed time, consciousness level on ED arrival, haematoma size, intraventricular extension, midline shift and infratentorial ICH. We further calculated the −2 log-likelihood decrease for each regression model incorporated with the BP values measured at different times to compare model fitness.

Results

After adjusting for the covariates, on-scene systolic BP (by 10 mm Hg incremental: OR = 1.126, 95% CI 1.015 to 1.265), diastolic BP (by 10 mm Hg incremental: OR=1.146, 95% CI 1.019 to 1.303) and mean arterial pressure (MAP) (by 10 mm Hg incremental: OR=1.225, 95% CI 1.057 to 1.443) were significantly associated with END; adding on-scene MAP into the regression model yielded the highest model fitness increase. Adding on-scene BPs into the regression model yielded higher model fitness increase than adding ED and admission BPs.

Conclusions

Few on-scene BP indices were associated with neuroworsening within 24 h after ED arrival in non-comatose SICH patients. Compared with BP measured on ED arrival or admission, on-scene BP had a stronger correlation with END.
Reducing radiation dose while maintaining diagnostic image quality of cerebral three-dimensional digital subtraction angiography: an in vivo study in swine
Authors: Pearl Monica S , Torok Collin M , Messina Steven A , Radvany Martin , Rao Swati N , Ehtiati Tina , Thompson Carol B , Gailloud Philippe
Published: October 2013

Background

Three-dimensional digital subtraction angiography (3D-DSA) is a modern technique that allows for better appreciation of complex vascular lesions. This study evaluates the impact of various dose reduction strategies on 3D-DSA image quality.

Methods

The standard manufacturer 5 s 0.36 μGy/frame setting was modified to create lower dose 3D-DSA protocols by varying the acquisition time (5 or 3 s) and/or dose per frame (0.36, 0.24, 0.17, and 0.10 μGy/f). All protocols were evaluated in three swine. Four raters measured a segment of the external carotid artery on two-dimensional multiplanar reconstruction images. The raters were also presented with three-dimensional volume rendered images from all protocols in a blinded manner and asked to choose the superior image. A full model analysis of variance with repeated measure factors was performed to compare mean differences in measurements between protocols.

Results

Measurement differences between the standard and low dose protocols were not clinically significant (<0.5 mm). All raters demonstrated high inter-rater reliability. The 5 s protocols were considered as qualitatively superior to the 3 s protocols. Delivered system doses ranged from 43.8 to 6.5 mGy. The 5 s 0.10 μGy/frame protocols generated 65–68% less delivered dose compared with the 5 s 0.36 μGy/frame setting.

Conclusions

Low dose 3D-DSA protocols with preserved image quality are achievable, and can help reduce unnecessary radiation exposure to both patients and operators. The 5 s low dose protocols generated clinically acceptable and superior images compared with the 3 s protocols, suggesting a more important role for acquisition time than dose per frame to maintain image quality.
Enhanced external counterpulsation improves peripheral resistance artery blood flow in patients with coronary artery disease
Authors: Avery Joseph C. , Beck Darren T. , Casey Darren P. , Sardina Paloma D. , Braith Randy W.
Published: October 2013

Enhanced external counterpulsation (EECP) increases coronary artery perfusion and improves endothelium-dependent vasodilation in peripheral muscular conduit arteries. It is unknown whether vasodilatory capacity is improved in the peripheral resistance vasculature. Here we provide novel evidence from the first randomized, sham-controlled study that EECP increases peak limb blood flow and improves endothelium-dependent vasodilation in both calf and forearm resistance arteries in patients with coronary artery disease.
Oceanographic influences on patterns in North Pacific salmon abundance
Authors: Stachura Megan M. , Mantua Nathan J. , Scheuerell Mark D.
Published: October 2013

We identified three dominant patterns of temporal variation (1951–2002) in the abundance of 34 stock groups of wild North American and Asian pink salmon (Oncorhynchus gorbuscha), chum salmon (Oncorhynchus keta), and sockeye salmon (Oncorhynchus nerka) that were related to patterns of oceanographic variability. We identified these patterns using three different ordination methods and found consistent patterns across these methods. Alaskan salmon dominated the most prominent pattern, which exhibited a positive abundance shift in the mid-1970s. In general, warm (cold) periods in the Gulf of Alaska and eastern Bering Sea corresponded with high (low) abundance years for these stock groups. The second abundance pattern captured differences among Asian, northern North American, and southern North American population groups and was associated with an intense, large-scale Aleutian Low. To our knowledge, this is the first analysis that identifies regional patterns of covariation in salmon abundance around the entire North Pacific Rim, and it highlights the existence of basin-wide covariations in wild salmon abundance that are associated with spatially coherent and regionally distinct patterns in North Pacific climate.
Influence of Artificial Ageing of Gas Diffusion Layers on the Water Management of PEM Fuel Cells
Authors: Arlt Tobias , Klages Merle , Manke Ingo , Messerschmidt Matthias , Riesemeier Heinrich , Hilger André , Scholta Joachim , Banhart John
Published: October 2013

The influence of artificial ageing of gas diffusion layers (GDL) on the water management within the GDL was investigated in-situ by synchrotron X-ray radiography. One GDL was subjected to an accelerated ageing procedure in 30 % H2O2 solution while another GDL was pristine. The GDLs were first assembled in test cells, after which the water distribution during operation was investigated. Radiographic measurements were combined with temporally resolved electrical analyses. Significant differences in cell voltage and water accumulation were observed in the GDL operated at steady-state conditions. In the cell containing the aged GDL, a higher water volume was found especially at the anode side while the cell voltage was lower.
Poly(vinyl alcohol)/Sulfosuccinic Acid (PVA/SSA) as Proton-Conducting Membranes for Fuel Cells: Effect of Cross-Linking and Plasticizer Addition
Authors: Zhang Jing , Liu Lingling , Ma Chengyu , Liu Yuyu , Qiao Jinli
Published: October 2013

A new type of cross-linked polymer blend membranes consisting of poly(vinyl alcohol) (PVA), sulfosuccinic acid (SSA) and plasticizer polyethylene glycol (PEG) have been prepared and evaluated as proton-conducting polymer electrolytes. The proton conductivity (σ
H
+) and water uptake (WU) of the membranes were investigated based on such points of view as thermal cross-linking and chemical cross-linking procedure, plasticizer effect and the content of SSA. It is found that the proton-conductivity increased with increasing the content of SSA and, reached up to 0.047 S cm-1 at room temperature with a polymer composition PVA/SSA being 1:0.5 by mass. The cross-linking modification and plasticizer addition also played an important role in σ
H
+ and WU. The membranes were characterized by thermogravimetric analysis (TGA), and the TG results showed that the thermal stability of the resultant membranes are improved due to the chemical cross-linking and plasticizer modifications.
Effect of Cooling the Cathode Grid Tab Stack on the Thermal Characteristics of Lithium-Ion Pouch Cells under Various Discharge Rates of Constant Current
Authors: Bazinski Stephen , Wang Xia
Published: October 2013

The aluminum tab on the cathode of Lithium-Ion pouch cells has a higher electrical ohmic resistance than the copper tab on the anode side. More importantly, the cathode grid tabs form a joint with the cell’s electrode, which is a source of Joule heating that can exacerbate thermal gradients within the cell core thus affecting the cell performance. In this research, the heat generated at the cathode tab joint of a 14Ah Lithium ion phosphate pouch cell has been quantified and their effect on the cell’s thermal gradients was studied during 3C and 8C rates of discharge. It was found that a thermal management system that removes the cathode grid tab heat can lower the overall cell temperature. However, at a 3C rate discharge, the removal of cathode tab heat can induce a greater thermal gradient within the cell core.
Electrochemical Reduction of CO2 on Modified Cu Electrodes Resulting from Pre-Electroreduction Annealed Cu in Different Electrolytes
Authors: Jiang Ping , Qiao Jinli , Fan Mengyang , Ma Chengyu , Liu Jianshe
Published: October 2013

In this paper, the modiﬁed Cu electrodes were prepared by annealing Cu foil in air and then electrochemically reducing the resulting Cu oxide layers in different electrolytes. The CO2 reduction activities of these electrodes were found to be strongly dependent on the annealing temperature and annealing time. Therefore, the effects of both annealing condition and pre-electroreduction in different solutions on electroreduction of CO2 were investigated on modified Cu electrodes. The modified Cu, donated as Cu-a, Cu-b, Cu-c, which electrochemically reduced in H2SO4, H3PO4 and NaOH, respectively, performed a favorable current density for CO2 reduction at a lower overpotential, and the current density reached about 80 mA cm-2 when the modified Cu reduced in H3PO4 at -1.5V vs Ag /AgCl, while about 76 mA cm-2 and 46 mV cm-2, for modified Cu reduced in H2SO4 and NaOH, respectively. For annealing conditions, the Cu foil after annealed at 500oC for 6h gave the best catalytic activity toward CO2 reduction regardless of pr-electroreduction in different solutions. In all cases, the modified electrodes perform a stable current density during the electrolysis time.
Numerical Model of Platinum Dissolution in Polymer Exchange Membrane Fuel Cells with Slow Proton Transfer
Authors: Katayama Noboru , Kogoshi Sumio
Published: October 2013

The slow proton transfer in the proton exchange membrane that causes a delay of membrane-phase potential changing against solid-phase one is taken into the numerical model and the difference between the experimental and simulation results is elucidated. The slow movement of proton transfer causes the higher cathode potential enough to induce the platinum dissolution and platinum oxide formation, which is 0.98 V and 1.188 V, respectively. The proton concentration is rapidly increased right after the potential rising and decrease to zero in 10 s. The calculation results show good agreement with the fact that the platinum degrade under the potential cycling condition of 10 s.
Measurement of the Diffusion Coefficient of Lithium in Tin Thin Films Including Phase Transformation Effects
Authors: Fok Eddie C W , Madden John D
Published: October 2013

In this work, use of the galvanostatic intermittent titration technique to extract lithium ion diffusion coefficients in tin thin films is studied. The measured results are first analyzed under the traditional solid solution assumptions. The change of phase in the electrode is then modeled using a moving boundary model, which more accurately predicts the potential transients during the galvanostatic pulse.
Fabrication and Electrochemical Performance of Unit Anode Supported Intermediate Temperature Solid Oxide Fuel Cells by Single Step Process
Authors: Sivasankaran Visweshwar , Combemale Lionel , Pera Marie-Cecile , Caboche Gilles
Published: October 2013

In this work micron sized particles of NiO, Gd0.1Ce0.9O1.9 (GDC10), and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF48) were used in the preparation of unit anode supported planar Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFC). The laboratories of ICB in Dijon and FC-LAB in Belfort France were aimed at preparation of large active area planar cells by low cost effective and efficient fabrication process with high performance and characterizing them in real time stack for use in APU application. The cells were prepared by novel single step and in expensive, process. These cells were characterized electrochemically to have I-V and I-P curves. The study of microstructure was carried on the cells. The initial results obtained were reported in this paper with still large possible room for optimization to further improve the performances of the cells. The maximum power density obtained was 466mW.cm-2 at 648°C. At 500°C 1.002V were obtained.
Characterization of Porous Thin-Film LSCF Cathode for Low-Temperature Operating µ-SOFC Prepared by Spray Pyrolysis Deposition
Authors: Sasaki Kazuya , Tomomichi Keita , Endo Yoichi , Kikai Kohei
Published: October 2013

We have successfully fabricated the porous thin film La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode by spray pyrolysis deposition (SPD) method. Main part of the film deposited at the substrate temperature of 350 oC was already perovskite structure and it became the single phase of the perovskite by the post annealing at the quite low temperature of 700 oC. When the cation concentration in the precursor solution was 0.5 mol/l and the substrate temperature during SPD process was 350 oC, the prepared film was became porous and consisted by hollow particles. Due to the large specific surface area of the film, the small cathode reaction resistance was achieved.
Titanium Oxide Anode in Inverse Structure for Dye Sensitized Solar Cell Applications by Electrophoretic Self-Assembly and Sol-Gel Processes
Authors: Louh Rong-Fuh , Huang Sean , Ho Danny
Published: October 2013

The aim of this study is to fabricate titanium oxide (TiO2) anode in inverse opal structure for dye sensitized solar cell (DSSC) applications via combined electrophoretic self-assembly (EPSA) and sol-gel processes. The polystyrene (PS) microspheres of 270 nm size were produced by emulsion-free polymerization. A stable colloid of PS microspheres in water-ethanol solvent was used to manufacture the 3-D photonic crystal template with periodic ordered opal structure onto the surface of indium tin oxide (ITO) coated glass substrate by EPSA. The titanium tetraisopropoxide (TTIP) sol precursor in mixture of ethanol and ethanol glycol was impregnated to fill up the voids inside PS template. The polycondensation of TiO2 was completed by absorption of ambient moisture. Further annealing at 450oC for 1 hr of samples was carried out for removal of PS microspheres and formation of TiO2 photonic crystal. The microstructure, composition, and crystalline phase analysis of obtained TiO2 in inverse opal structure were examined by SEM, EDS, and XRD.
Semiconductors as Selective Redox Electrodes
Authors: Usgaocar Ashwin R , Wang Lisheng , Hong Zhen , Madden John D. W.
Published: October 2013

Electrodes that selectively exchange charge with only certain redox couples in a mixture could improve the performance of photogalvanic and bio-photovoltaic cells described in the literature. One avenue to achieve selectivity is through the use of semiconducting rather than metallic electrodes to exploit the presence of the bandgap to control reaction rates. In this paper, Fluorine doped Tin oxide (F:SnO2), Copper(II) oxide (CuO) and Nickel oxide (NiO) electrodes are investigated as a means to achieving selective redox reactions. The reactions of methyl viologen, ferricyanide/ferrocyanide and ferric/ferrous couples on the three semiconducting electrodes were studied using cyclic voltammetry and sampled current voltammetry. The rate of electron transfer between the electrodes and the redox couples depended on the difference between the semiconductor majority carrier band edge and the standard redox potential of the redox couple. Most noticeably, the rate constant of methyl viologen on F:SnO2 was two orders of magnitude higher than that for the ferric/ferrous ion. Similar results were obtained with the NiO electrode while electrochemical instability hampered the tests of the CuO electrode.