bluuebunny/crossref_metadata_2025 huggingface dataset:
High affinity and low affinity heteromeric nicotinic acetylcholine receptors at central synapses
Authors: d’Incamps Boris Lamotte , Ascher Philippe
Published: May 2014

Most neuronal heteromeric nicotinic receptors seem able to adopt two different stochiometries depending on the ratio of α and β subunits. In recombinant receptors these two stoichiometries have been associated with different affinities to ACh, but it is not known which stoichiometry is present at nicotinic synapses in the nervous system. One possible clue to this identification is the speed of decay of the synaptic currents. In many ionotropic receptors this speed has been linked to the dissociation rate of the transmitter, which is itself related to its affinity. On this basis we propose that, at the synapse between motoneuron and Renshaw cells, the heteromeric nicotinic receptors are mostly low affinity receptors and suggest that, in contrast, the very slow decay of some synaptic currents recorded in other parts of the brain signs the presence of high affinity receptors rather than volume transmission.
Chronic intermittent hypoxia–hypercapnia blunts heart rate responses and alters neurotransmission to cardiac vagal neurons
Authors: Dyavanapalli Jhansi , Jameson Heather , Dergacheva Olga , Jain Vivek , Alhusayyen Mona , Mendelowitz David
Published: May 2014

Key points

Chronic intermittent hypoxia–hypercapnia (CIHH) in adult rats evoked hypertension and blunted the heart rate responses to acute hypoxia–hypercapnia (H–H).

CIHH induced an increase in spontaneous inhibitory and decreased excitatory neurotransmission to cardiac vagal neurons.

CIHH completely abolished acute H–H evoked inhibition of GABAergic while facilitating glycinergic neurotransmission to cardiac vagal neurons of nucleus ambiguus.

These changes with CIHH inhibit cardiac vagal neurons to result in diminished cardioprotective vagal activity to the heart, characteristic of obstructive sleep apnoea.

Patients with obstructive sleep apnoea experience chronic intermittent hypoxia–hypercapnia (CIHH) during sleep that elicit sympathetic overactivity and diminished parasympathetic activity to the heart, leading to hypertension and depressed baroreflex sensitivity. The parasympathetic control of heart rate arises from pre‐motor cardiac vagal neurons (CVNs) located in nucleus ambiguus (NA) and dorsal motor nucleus of the vagus (DMNX). The mechanisms underlying diminished vagal control of heart rate were investigated by studying the changes in blood pressure, heart rate, and neurotransmission to CVNs evoked by acute hypoxia–hypercapnia (H–H) and CIHH. In vivo telemetry recordings of blood pressure and heart rate were obtained in adult rats during 4 weeks of CIHH exposure. Retrogradely labelled CVNs were identified in an in vitro brainstem slice preparation obtained from adult rats exposed either to air or CIHH for 4 weeks. Postsynaptic inhibitory or excitatory currents were recorded using whole cell voltage clamp techniques. Rats exposed to CIHH had increases in blood pressure, leading to hypertension, and blunted heart rate responses to acute H–H. CIHH induced an increase in GABAergic and glycinergic neurotransmission to CVNs in NA and DMNX, respectively; and a reduction in glutamatergic neurotransmission to CVNs in both nuclei. CIHH blunted the bradycardia evoked by acute H–H and abolished the acute H–H evoked inhibition of GABAergic transmission while enhancing glycinergic neurotransmission to CVNs in NA. These changes with CIHH inhibit CVNs and vagal outflow to the heart, both in acute and chronic exposures to H–H, resulting in diminished levels of cardioprotective parasympathetic activity to the heart as seen in OSA patients.
Preparation and Investigation of p-GaAs/n-Cd1-xZnxS1-yTey Heterojunctions Deposited by Electrochemical Deposition
Authors: Mamedov Huseyn M. , Konya Zoltan , Muradov Mustafa B. , Kukovecz Akos , Kordas Krisztian , Hashim Daniel P. , Mamedov Vusal U.
Published: May 2014

Anisotype heterojunctions of p-GaAs/n-Cd1-xZnxS1-yTey have been fabricated by preparing n-type Cd1-xZnxS1-yTey thin films onto p-GaAs single crystal wafers using an electrochemical deposition method. The voltammetric behavior of the Cd1-xZnxS1-yTey thin films on GaAs substrates from aqueous solutions was studied. Electrical and photoelectrical properties of heterojunctions were studied depending on the Cd1-xZnxS1-yTey films composition (x = 0.1 ÷ 0.8; y = 0.2; 0.4; 0.9) and heat treatment (HT) regime in argon atmosphere (100–450 °С during 3–16 min). Under AM1.5 conditions, the open-circuit voltage, short-circuit current, fill factor, and efficiency of our best cell, was Voc = 584 mV, Jsc = 14.54 mA/cm2, FF = 0.6, and η = 6.7%, respectively.
A New Approach for Fabricating Low Cost DSSC by Using Carbon-Ink From Inkjet Printer and Its Improvement Efficiency by Depositing Metal Bridge Between Titanium Dioxide Particles
Authors: Saehana Sahrul , Darsikin  , Yuliza Elfi , Arifin Pepen , Khairurrijal  , Abdullah Mikrajuddin
Published: May 2014

We report the fabrication of a dye-sensitized solar cell (DSSC) using low-cost materials (carbon ink from an inkjet printer coated on glass as the counter electrode) and made by a combination of spray deposition and doctor blade methods. We noted that the efficiency of the DSSC with the carbon-coated electrode (1.13%) was comparable to that with a platinum-coated counter electrode (1.16%). We also proposed an equivalent circuit for this solar cell. The value of the charge-transfer resistance was determined both experimentally and analytically, and we found that both approaches produced the same results. Moreover, we improved the efficiency of DSSC based carbon by depositing copper nanoparticle into the space between Titanium Dioxide (TiOv2) nanoparticle using electroplating methods.
Design and Optimization of a Contact-Aided Compliant Mechanism for Passive Bending
Authors: Tummala Yashwanth , Wissa Aimy , Frecker Mary , Hubbard James E.
Published: May 2014

A contact-aided compliant mechanism (CCM) called a compliant spine (CS) is presented in this paper. It is flexible when bending in one direction and stiff when bending in the opposite direction, giving it a nonlinear bending stiffness. The fundamental element of this mechanism is a compliant joint (CJ), which consists of a compliant hinge (CH) and contact surfaces. The design of the compliant joint and the number of compliant joints in a compliant spine determine its stiffness. This paper presents the design and optimization of such a compliant spine. A multi-objective optimization problem with three objectives is formulated in order to perform the design optimization of the compliant spine. The goal of the optimization is to minimize the peak stress and mass while maximizing the deflection, subject to geometric and other constraints. Flapping wing unmanned air vehicles, also known as ornithopters, are used as a case study in this paper to test the accuracy of the design optimization procedure and to prove the efficacy of the compliant spine design. The optimal compliant spine designs obtained from the optimization procedure are fabricated, integrated into the ornithopter's wing leading edge spar, and flight tested. Results from the flight tests prove the ability of the compliant spine to produce an asymmetry in the ornithopter's wing kinematics during the up and down strokes.
In Situ and Ex Situ Studies on the Degradation of Pd/C Catalyst for Proton Exchange Membrane Fuel Cells
Authors: Tang Yongfu , Mu Shichun , Yu Shengxue , Zhao Yufeng , Wang Hongchao , Gao Faming
Published: May 2014

To investigate the degradation mechanism of the as-prepared Pd/C catalyst, in situ and ex situ accelerated stress tests were carried out via potential cycling. Durability tests of the single cells with Pd/C catalysts were performed through an interval constant current density mode. Electrochemical impedance spectroscopy (EIS) was applied to measure the impedance of the single cell during degradation tests. Results indicate that the degradation of Pd/C catalyst may be attributed to the phase transition of absorbed α-phase PdH to β-phase PdH, the dissolution of Pd metal, and the size increase of Pd nanoparticles. Moreover, the degradation of single cell may be predominantly ascribed to the degradation of catalyst, the deterioration of contact between electronic/ionic conductors, as well as the flooding of gas diffusion channels.
Fuzzy Logic Based Controller for a Grid-Connected Solid Oxide Fuel Cell Power Plant
Authors: Chatterjee Kalyan , Shankar Ravi , Kumar Amit
Published: May 2014

This paper describes a mathematical model of a solid oxide fuel cell (SOFC) power plant integrated in a multimachine power system. The utilization factor of a fuel stack maintains steady state by tuning the fuel valve in the fuel processor at a rate proportional to a current drawn from the fuel stack. A suitable fuzzy logic control is used for the overall system, its objective being controlling the current drawn by the power conditioning unit and meet a desirable output power demand. The proposed control scheme is verified through computer simulations.
Sensitive Detection of Xanthomonas oryzae Pathovars oryzae and oryzicola by Loop-Mediated Isothermal Amplification
Authors: Lang Jillian M. , Langlois Paul , Nguyen Marian Hanna R. , Triplett Lindsay R. , Purdie Laura , Holton Timothy A. , Djikeng Appolinaire , Vera Cruz Casiana M. , Verdier Valérie , Leach Jan E.
Published: May 2014

Molecular diagnostics for crop diseases can enhance food security by enabling the rapid identification of threatening pathogens and providing critical information for the deployment of disease management strategies. Loop-mediated isothermal amplification (LAMP) is a PCR-based tool that allows the rapid, highly specific amplification of target DNA sequences at a single temperature and is thus ideal for field-level diagnosis of plant diseases. We developed primers highly specific for two globally important rice pathogens,
Xanthomonas oryzae
pv. oryzae, the causal agent of bacterial blight (BB) disease, and
X. oryzae
pv. oryzicola, the causal agent of bacterial leaf streak disease (BLS), for use in reliable, sensitive LAMP assays. In addition to pathovar distinction, two assays that differentiate
X. oryzae
pv. oryzae by African or Asian lineage were developed. Using these LAMP primer sets, the presence of each pathogen was detected from DNA and bacterial cells, as well as leaf and seed samples. Thresholds of detection for all assays were consistently 10
4
to 10
5
CFU ml
−1
, while genomic DNA thresholds were between 1 pg and 10 fg. Use of the unique sequences combined with the LAMP assay provides a sensitive, accurate, rapid, simple, and inexpensive protocol to detect both BB and BLS pathogens.
Targeted Tandem Duplication of a Large Chromosomal Segment in Aspergillus oryzae
Authors: Takahashi Tadashi , Sato Atsushi , Ogawa Masahiro , Hanya Yoshiki , Oguma Tetsuya
Published: May 2014

We describe here the first successful construction of a targeted tandem duplication of a large chromosomal segment in
Aspergillus oryzae
. The targeted tandem chromosomal duplication was achieved by using strains that had a 5′-deleted
pyrG
upstream of the region targeted for tandem chromosomal duplication and a 3′-deleted
pyrG
downstream of the target region. Consequently, strains bearing a 210-kb targeted tandem chromosomal duplication near the centromeric region of chromosome 8 and strains bearing a targeted tandem chromosomal duplication of a 700-kb region of chromosome 2 were successfully constructed. The strains bearing the tandem chromosomal duplication were efficiently obtained from the regenerated protoplast of the parental strains. However, the generation of the chromosomal duplication did not depend on the introduction of double-stranded breaks (DSBs) by I-SceI. The chromosomal duplications of these strains were stably maintained after five generations of culture under nonselective conditions. The strains bearing the tandem chromosomal duplication in the 700-kb region of chromosome 2 showed highly increased protease activity in solid-state culture, indicating that the duplication of large chromosomal segments could be a useful new breeding technology and gene analysis method.
Influence of DNA Extraction Method, 16S rRNA Targeted Hypervariable Regions, and Sample Origin on Microbial Diversity Detected by 454 Pyrosequencing in Marine Chemosynthetic Ecosystems
Authors: Cruaud Perrine , Vigneron Adrien , Lucchetti-Miganeh Céline , Ciron Pierre Emmanuel , Godfroy Anne , Cambon-Bonavita Marie-Anne
Published: May 2014

Next-generation sequencing (NGS) opens up exciting possibilities for improving our knowledge of environmental microbial diversity, allowing rapid and cost-effective identification of both cultivated and uncultivated microorganisms. However, library preparation, sequencing, and analysis of the results can provide inaccurate representations of the studied community compositions. Therefore, all these steps need to be taken into account carefully. Here we evaluated the effects of DNA extraction methods, targeted 16S rRNA hypervariable regions, and sample origins on the diverse microbes detected by 454 pyrosequencing in marine cold seep and hydrothermal vent sediments. To assign the reads with enough taxonomic precision, we built a database with about 2,500 sequences from
Archaea
and
Bacteria
from deep-sea marine sediments, affiliated according to reference publications in the field. Thanks to statistical and diversity analyses as well as inference of operational taxonomic unit (OTU) networks, we show that (i) while DNA extraction methods do not seem to affect the results for some samples, they can lead to dramatic changes for others; and (ii) the choice of amplification and sequencing primers also considerably affects the microbial community detected in the samples. Thereby, very different proportions of pyrosequencing reads were obtained for some microbial lineages, such as the archaeal ANME-1, ANME-2c, and MBG-D and deltaproteobacterial subgroups. This work clearly indicates that the results from sequencing-based analyses, such as pyrosequencing, should be interpreted very carefully. Therefore, the combination of NGS with complementary approaches, such as fluorescence
in situ
hybridization (FISH)/catalyzed reporter deposition (CARD)-FISH or quantitative PCR (Q-PCR), would be desirable to gain a more comprehensive picture of environmental microbial communities.
Characterization of a Nitrilase and a Nitrile Hydratase from Pseudomonas sp. Strain UW4 That Converts Indole-3-Acetonitrile to Indole-3-Acetic Acid
Authors: Duca Daiana , Rose David R. , Glick Bernard R.
Published: May 2014

Indole-3-acetic acid (IAA) is a fundamental phytohormone with the ability to control many aspects of plant growth and development.Pseudomonassp. strain UW4 is a rhizospheric plant growth-promoting bacterium that produces and secretes IAA. While several putative IAA biosynthetic genes have been reported in this bacterium, the pathways leading to the production of IAA in strain UW4 are unclear. Here, the presence of the indole-3-acetamide (IAM) and indole-3-acetaldoxime/indole-3-acetonitrile (IAOx/IAN) pathways of IAA biosynthesis is described, and the specific role of two of the enzymes (nitrilase and nitrile hydratase) that mediate these pathways is assessed. The genes encoding these two enzymes were expressed inEscherichia coli, and the enzymes were isolated and characterized. Substrate-feeding assays indicate that the nitrilase produces both IAM and IAA from the IAN substrate, while the nitrile hydratase only produces IAM. The two nitrile-hydrolyzing enzymes have very different temperature and pH optimums. Nitrilase prefers a temperature of 50°C and a pH of 6, while nitrile hydratase prefers 4°C and a pH of 7.5. Based on multiple sequence alignments and motif analyses, physicochemical properties and enzyme assays, it is concluded that the UW4 nitrilase has an aromatic substrate specificity. The nitrile hydratase is identified as an iron-type metalloenzyme that does not require the help of a P47K activator protein to be active. These data are interpreted in terms of a preliminary model for the biosynthesis of IAA in this bacterium.
Bifidobacterium longum subsp. longum Exo-β-1,3-Galactanase, an Enzyme for the Degradation of Type II Arabinogalactan
Authors: Fujita Kiyotaka , Sakaguchi Takenori , Sakamoto Ayami , Shimokawa Michiko , Kitahara Kanefumi
Published: May 2014

Type II arabinogalactan (AG-II) is a suitable carbohydrate source for
Bifidobacterium longum
subsp.
longum
, but the degradative enzymes have never been characterized. In this study, we characterized an exo-β-1,3-galactanase, BLLJ_1840, belonging to glycoside hydrolase family 43 from
B. longum
subsp.
longum
JCM1217. The recombinant BLLJ_1840 expressed in
Escherichia coli
hydrolyzed β-1,3-linked galactooligosaccharides but not β-1,4- and β-1,6-linked galactooligosaccharides. The enzyme also hydrolyzed larch wood arabinogalactan (LWAG), which comprises a β-1,3-linked galactan backbone with β-1,6-linked galactan side chains. The
k
cat
/

K
m

ratio of dearabinosylated LWAG was 24-fold higher than that of β-1,3-galactan. BLLJ_1840 is a novel type of exo-β-1,3-galactanase with a higher affinity for the β-1,6-substituted β-1,3-galactan than for nonsubstituted β-1,3-galactan. BLLJ_1840 has 27% to 28% identities with other characterized exo-β-1,3-galactanases from bacteria and fungi. The homologous genes are conserved in several strains of
B. longum
subsp.
longum
and
B. longum
subsp.
infantis
but not in other bifidobacteria. Transcriptional analysis revealed that BLLJ_1840 is intensively induced with BLLJ_1841, an endo-β-1,6-galactanase candidate, in the presence of LWAG. This is the first report of exo-β-1,3-galactanase in bifidobacteria, which is an enzyme used for the acquisition of AG-II in
B. longum
subsp.
longum
.
Direct Interspecies Electron Transfer between Geobacter metallireducens and Methanosarcina barkeri
Authors: Rotaru Amelia-Elena , Shrestha Pravin Malla , Liu Fanghua , Markovaite Beatrice , Chen Shanshan , Nevin Kelly P. , Lovley Derek R.
Published: May 2014

Direct interspecies electron transfer (DIET) is potentially an effective form of syntrophy in methanogenic communities, but little is known about the diversity of methanogens capable of DIET. The ability of
Methanosarcina barkeri
to participate in DIET was evaluated in coculture with
Geobacter metallireducens
. Cocultures formed aggregates that shared electrons via DIET during the stoichiometric conversion of ethanol to methane. Cocultures could not be initiated with a pilin-deficient
G. metallireducens
strain, suggesting that long-range electron transfer along pili was important for DIET. Amendments of granular activated carbon permitted the pilin-deficient
G. metallireducens
isolates to share electrons with
M. barkeri
, demonstrating that this conductive material could substitute for pili in promoting DIET. When
M. barkeri
was grown in coculture with the H
2
-producing
Pelobacter carbinolicus
, incapable of DIET,
M. barkeri
utilized H
2
as an electron donor but metabolized little of the acetate that
P. carbinolicus
produced. This suggested that H
2
, but not electrons derived from DIET, inhibited acetate metabolism.
P. carbinolicus-M. barkeri
cocultures did not aggregate, demonstrating that, unlike DIET, close physical contact was not necessary for interspecies H
2
transfer.
M. barkeri
is the second methanogen found to accept electrons via DIET and the first methanogen known to be capable of using either H
2
or electrons derived from DIET for CO
2
reduction. Furthermore,
M. barkeri
is genetically tractable, making it a model organism for elucidating mechanisms by which methanogens make biological electrical connections with other cells.
Formate Oxidation-Driven Calcium Carbonate Precipitation by Methylocystis parvus OBBP
Authors: Ganendra Giovanni , De Muynck Willem , Ho Adrian , Arvaniti Eleni Charalampous , Hosseinkhani Baharak , Ramos Jose Angel , Rahier Hubert , Boon Nico
Published: May 2014

Microbially induced carbonate precipitation (MICP) applied in the construction industry poses several disadvantages such as ammonia release to the air and nitric acid production. An alternative MICP from calcium formate by
Methylocystis parvus
OBBP is presented here to overcome these disadvantages. To induce calcium carbonate precipitation,
M. parvus
was incubated at different calcium formate concentrations and starting culture densities. Up to 91.4% ± 1.6% of the initial calcium was precipitated in the methane-amended cultures compared to 35.1% ± 11.9% when methane was not added. Because the bacteria could only utilize methane for growth, higher culture densities and subsequently calcium removals were exhibited in the cultures when methane was added. A higher calcium carbonate precipitate yield was obtained when higher culture densities were used but not necessarily when more calcium formate was added. This was mainly due to salt inhibition of the bacterial activity at a high calcium formate concentration. A maximum 0.67 ± 0.03 g of CaCO
3
g of Ca(CHOOH)
2
−1
calcium carbonate precipitate yield was obtained when a culture of 10
9
cells ml
−1
and 5 g of calcium formate liter
−1
were used. Compared to the current strategy employing biogenic urea degradation as the basis for MICP, our approach presents significant improvements in the environmental sustainability of the application in the construction industry.
Handling Temperature Bursts Reaching 464°C: Different Microbial Strategies in the Sisters Peak Hydrothermal Chimney
Authors: Perner Mirjam , Gonnella Giorgio , Kurtz Stefan , LaRoche Julie
Published: May 2014

The active venting Sisters Peak (SP) chimney on the Mid-Atlantic Ridge holds the current temperature record for the hottest ever measured hydrothermal fluids (400°C, accompanied by sudden temperature bursts reaching 464°C). Given the unprecedented temperature regime, we investigated the biome of this chimney with a focus on special microbial adaptations for thermal tolerance. The SP metagenome reveals considerable differences in the taxonomic composition from those of other hydrothermal vent and subsurface samples; these could be better explained by temperature than by other available abiotic parameters. The most common species to which SP genes were assigned were thermophilicAciduliprofundumsp. strain MAR08-339 (11.8%),Hippea maritima(3.8%),Caldisericum exile(1.5%), andCaminibacter mediatlanticus(1.4%) as well as to the mesophilicNiastella koreensis(2.8%). A statistical analysis of associations between taxonomic and functional gene assignments revealed specific overrepresented functional categories: forAciduliprofundum, protein biosynthesis, nucleotide metabolism, and energy metabolism genes; forHippeaandCaminibacter, cell motility and/or DNA replication and repair system genes; and forNiastella, cell wall and membrane biogenesis genes. Cultured representatives of these organisms inhabit different thermal niches; i.e.,Aciduliprofundumhas an optimal growth temperature of 70°C,HippeaandCaminibacterhave optimal growth temperatures around 55°C, andNiastellagrows between 10 and 37°C. Therefore, we posit that the different enrichment profiles of functional categories reflect distinct microbial strategies to deal with the different impacts of the local sudden temperature bursts in disparate regions of the chimney.
The
adnAB
Locus, Encoding a Putative Helicase-Nuclease Activity, Is Essential in Streptomyces
Authors: Zhang Lingli , Nguyen Hoang Chuong , Chipot Ludovic , Piotrowski Emilie , Bertrand Claire , Thibessard Annabelle , Leblond Pierre
Published: May 2014

Homologous recombination is a crucial mechanism that repairs a wide range of DNA lesions, including the most deleterious ones, double-strand breaks (DSBs). This multistep process is initiated by the resection of the broken DNA ends by a multisubunit helicase-nuclease complex exemplified by
Escherichia coli
RecBCD,
Bacillus subtilis
AddAB, and newly discovered
Mycobacterium tuberculosis
AdnAB. Here we show that in
Streptomyces
, neither
recBCD
nor
addAB
homologues could be detected. The only putative helicase-nuclease-encoding genes identified were homologous to
M. tuberculosis
adnAB
genes. These genes are conserved as a single copy in all sequenced genomes of
Streptomyces
. The disruption of
adnAB
in
Streptomyces ambofaciens
and
Streptomyces coelicolor
could not be achieved unless an ectopic copy was provided, indicating that
adnAB
is essential for growth. Both
adnA
and
adnB
genes were shown to be inducible in response to DNA damage (mitomycin C) and to be independently transcribed. Introduction of
S. ambofaciens
adnAB
genes in an
E. coli
recB
mutant restored viability and resistance to UV light, suggesting that
Streptomyces
AdnAB could be a functional homologue of RecBCD and be involved in DNA damage resistance.
Control of Gene Expression at a Bacterial Leader RNA, the
agn43
Gene Encoding Outer Membrane Protein Ag43 of Escherichia coli
Authors: Wallecha Anu , Oreh Heather , van der Woude Marjan W. , deHaseth Pieter L.
Published: May 2014

The family of
agn
alleles in
Escherichia coli
pathovars encodes autotransporters that have been implicated in biofilm formation, autoaggregation, and attachment to cells. The alleles all have long leader RNAs preceding the Ag43 translation initiation codon. Here we present an analysis of the
agn43
leader RNA from
E. coli
K-12. We demonstrate the presence of a rho-independent transcription terminator just 28 bp upstream of the main translation start codon and show that it is functional
in vitro
. Our data indicate that an as-yet-unknown mechanism of antitermination of transcription must be operative in earlier phases of growth. However, as bacterial cell cultures mature, progressively fewer transcripts are able to bypass this terminator. In the K-12 leader sequence, two in-frame translation initiation codons have been identified, one upstream and the other downstream of the transcription terminator. For optimal
agn43
expression, both codons need to be present. Translation from the upstream start codon leads to increased downstream
agn43
expression. Our findings have revealed two novel modes of regulation of
agn43
expression in the leader RNA in addition to the previously well-characterized regulation of phase variation at the
agn43
promoter.
Modification of Streptococcus mutans Cnm by PgfS Contributes to Adhesion, Endothelial Cell Invasion, and Virulence
Authors: Avilés-Reyes Alejandro , Miller James H. , Simpson-Haidaris Patricia J. , Hagen Fred K. , Abranches Jacqueline , Lemos José A.
Published: May 2014

Expression of the surface protein Cnm has been directly implicated in the ability of certain strains of
Streptococcus mutans
to bind to collagen and to invade human coronary artery endothelial cells (HCAEC) and in the killing of
Galleria mellonella
. Sequencing analysis of Cnm
+
strains revealed that
cnm
is located between the core genes SMU.2067 and SMU.2069. Reverse transcription-PCR (RT-PCR) analysis showed that
cnm
is cotranscribed with SMU.2067, encoding a putative glycosyltransferase referred to here as PgfS (
p
rotein
g
lycosyltrans
f
erase of
s
treptococci). Notably, Cnm contains a threonine-rich domain predicted to undergo
O
-linked glycosylation. The previously shown abnormal migration pattern of Cnm, the presence of the threonine-rich domain, and the molecular linkage of
cnm
with
pgfS
lead us to hypothesize that PgfS modifies Cnm. A Δ
pgfS
strain showed defects in several traits associated with Cnm expression, including collagen binding, HCAEC invasion, and killing of
G. mellonella
. Western blot analysis revealed that Cnm from the Δ
pgfS
mutant migrated at a lower molecular weight than that from the parent strain. In addition, Cnm produced by Δ
pgfS
was highly susceptible to proteinase K degradation, in contrast to the high-molecular-weight Cnm version found in the parent strain. Lectin-binding analyses confirmed the glycosylated nature of Cnm and strongly suggested the presence of
N
-acetylglucosamine residues attached to Cnm. Based on these findings, the phenotypes observed in Δ
pgfS
are most likely associated with defects in Cnm glycosylation that affects protein function, stability, or both. In conclusion, this study demonstrates that Cnm is a glycoprotein and that posttranslational modification mediated by PgfS contributes to the virulence-associated phenotypes linked to Cnm.
Acute renal failure associated with albendazole therapy in a patient with trichinosis
Authors: Batzlaff Cassandra Marie , Pupaibool Jakrapun , Sohail M Rizwan
Published: May 2014

A 72-year-old Caucasian woman presented with a 3-week history of confusion, cramping abdominal pain, nausea, vomiting, diarrhoea, fatigue and dehydration. By history, she reported consumption of raw pork and bacon that was salted and cured in brine, but not boiled or cooked. Laboratory testing was significant for an absolute eosinophil count of 3.09×109/L. She was found to have a positiveTrichinellaserology by ELISA testing. Based on history of raw pork consumption, symptoms, peripheral eosinophilia and positive serology, a diagnosis of trichinosis was made. Treatment was started with oral albendazole. Following initiation of therapy, the patient developed acute kidney injury presumably secondary to albendazole. Therapy was discontinued. Her serum creatinine returned to baseline over the following days. The decision was made to proceed with observation alone, as she did not tolerate treatment. At the 3-week follow-up, her gastrointestinal symptoms had improved and her eosinophilia had resolved.
Recurrent hypoglycaemia: a delayed presentation of Sheehan syndrome
Authors: Kumar Naresh , Singh Pratap , Kumar Jyoti , Dhanwal Dinesh Kumar
Published: May 2014

Sheehan syndrome is a rare but potentially serious complication of postpartum haemorrhage. The diagnosis can often be delayed by many years as symptoms may be subtle. We report the case of a 45-year-old woman who presented to the medical emergency unit with acute onset altered sensorium. On further evaluation she was found to have severe hypoglycaemia which was corrected by giving intravenous dextrose. On detailed clinical evaluation, she had a history of agalactia and amenorrhoea following her last pregnancy which was 15 years ago. She had a history of excessive postpartum bleeding during her last delivery. MRI of the brain showed empty sella and hormonal evaluation revealed adenohypophyseal insufficiency as evident from decreased levels of cortisol, thyroid-stimulating hormone, triiodothyronine, free thyroxine, follicle-stimulating hormone, luteinising hormone and prolactin. Based on clinical, radiological and laboratory parameters her final diagnosis was Sheehan syndrome with hypoglycaemia.
Endometrial adenocarcinoma in one horn of a didelphic uterus with vaginal duplication
Authors: Vázquez Vicente Daniel , Di Fiore Hugo Ariel , Garcia-Foncillas Jesús , Plaza Arranz Javier
Published: May 2014

A 59-year-old female patient presented with vaginal bleeding. A didelphic uterus with vaginal duplication was diagnosed on the basis of physical examination and radiology tests. Biopsy revealed an endometrial cancer in the left horn, while the right was atrophic. Laparoscopic hysterectomy, bilateral salphingo-oophorectomy, pelvic and para-aortic lymphadenectomy were performed. According to Federation International of Gynecology and Obstetrics (FIGO) staging the tumour was classified Ib. The adjuvant therapy was vaginal cuff brachytherapy. After 6 months, she has no evidence of the disease.
Clinical features of genetic Creutzfeldt-Jakob disease with V180I mutation in the prion protein gene
Authors: Qina Temu , Sanjo Nobuo , Hizume Masaki , Higuma Maya , Tomita Makoto , Atarashi Ryuichiro , Satoh Katsuya , Nozaki Ichiro , Hamaguchi Tsuyoshi , Nakamura Yosikazu , Kobayashi Atsushi , Kitamoto Tetsuyuki , Murayama Shigeo , Murai Hiroyuki , Yamada Masahito , Mizusawa Hidehiro
Published: May 2014

Objectives

Genetic Creutzfeldt-Jakob disease (CJD) due to V180I mutation in the prion protein gene (PRNP) is of great interest because of the differences from sporadic CJD and other genetic prion diseases in terms of clinical features, as well as pathological and biochemical findings. However, few systematic observations about the clinical features in patients with this unique mutation have been published. Therefore, the goal of this study was to relate this mutation to other forms of CJD from a clinical perspective.

Design

We analysed clinical symptoms, prion protein genetics, biomarkers in cerebrospinal fluid (CSF) and MRI of patients.

Participants

186 Japanese patients with the V180I mutation inPRNP.

Results

Our results indicate that the V180I mutation caused CJD at an older age, with a slower progression and a lower possibility of developing myoclonus, cerebellar, pyramidal signs and visual disturbance compared with classical sporadic CJD with methionine homozygosity at codon 129 ofPRNP. Cognitive impairment was the major symptom. Diffuse hyperintensity of the cerebral cortex in diffusion-weighted MRI might be helpful for diagnosis. Owing to the low positivity of PrPScin the CSF, genetic analysis was often required for a differential diagnosis from slowly progressive dementia.

Conclusions

We conclude that the V180I mutation inPRNPproduces a late-developing and slow-developing, less severe form of CJD, whose lesions are uniquely distributed compared with sporadic and other genetic forms of CJD.
Positive correlation between the expression of hEag1 and HIF-1α in breast cancers: an observational study
Authors: Lai Qingxuan , Wang Ting , Guo Qingqing , Zhang Yuxiang , Wang Youxin , Yuan Li , Ling Rui , He Yan , Wang Wei
Published: May 2014

Objectives

To explore the expression patterns of Eag1 (ether á go-go 1) and HIF-1α (hypoxia-inducible factor 1α) in a cohort of patients with breast cancer.

Setting

Department of general surgery in an upper first-class hospital in Xi'an, China.

Participants

A total of 112 female Han Chinese patients with a diagnosis of invasive ductal carcinoma were included. Patients with main internal diseases, such as cardiovascular, endocrine, gastroenterological, haematological, infectious diseases, etc, were excluded.

Primary and secondary outcome measures

Expression profiles of Eag1 and HIF-1α.

Results

Eag1 and HIF-1α were overexpressed in the tumour tissues compared with the pair-matched control tissues, p=0.002 and <0.001, respectively. The expression of Eag1 and HIF-1α was negatively correlated with tumour size, p=0.032 and p=0.025, respectively, and lymph node status (p=0.040, p=0.032, respectively). The coexpression of Eag1 and HIF-1α was correlated with tumour size (p=0.012), lymph node status (p=0.027) and tumour stage (p=0.036). HIF-1α has a strong correlation with hEag1 expression (κ=0.731, p<0.001).

Conclusions

HIF-1α expression has a strong correlation with hEag1 expression. We are the first to attempt to explore the correlation at the population level.
Improving the efficiency of discharge summary completion by linking to preexisiting patient information databases
Authors: Chan Samuel , P Maurice Andrew , W Pollard Clifford , J Ayre Stephen , L Walters Darren , E Ward Helen
Published: May 2014

The discharge summary (DS) is a document that contains the diagnosis, comorbidities, procedures, complications, and future treatment plan for a particular patient after an inpatient hospital stay. The DS is completed by junior medical staff and is delivered to the general practitioner (GP). DS completion is time consuming and tedious, and DSs are usually not completed within the recommended time frame after a patient is discharged. Time spent completing DSs correlate to junior doctor overtime, which costs the hospital money in overtime pay.

Information that is required in the DS is generally already entered into numerous electronic information systems in the hospital, including the “electronic patient journey board” which lists all the patients in a given ward with their clinical information. This information is constantly updated by all staff in the hospital. A program was developed that transferred this information directly into the patient DS. Ten junior doctors in two departments kept daily records for one week of the time spent compiling DSs, the time at work and the actual overtime claimed, before and after the introduction of the intervention.

The mean (± SD) time for DS compilation per week reduced by 2.8 (± 2.4) hours from 10.0 (±3.5) hours (p<0.01) and the mean overtime worked per week reduced by 2.8 (± 3.1) hours from 8.5 (± 4.4) hours (p<0.05). The mean overtime claimed reduced by 1.8 (± 2.8) hours from 5.3 (± 5.4) hours per week (p<0.05), resulting in reduction in mean overtime payment of $114.95 from $290.57 per doctor, per week. Extrapolating to the 60 ward based junior doctors, the potential annual savings for the hospital budget are over $350,000. Additionally, the number of DSs completed within 48 hours increased from 45% to 58%.

In summary, the transfer of electronic data from the electronic patient journey board to the discharge summary program has yielded improvements in DS completion rates and overtime worked by medical staff, resulting in significant reduction in overtime costs.
Improving the education and experience of foundation doctors in general surgery
Authors: Martel Gareth , Magee Cathy
Published: May 2014

Reduced working hours and fragmentation of the surgical firm has resulted in a gradual change in FY1 duties. Locally, FY1 doctors were no longer routinely seeing surgical emergency admissions, while FY1s informally reported reduced confidence in dealing with surgical emergencies. The goal of this project was to assess the current training of FY1 doctors within the unit, and to attempt to improve this by increasing exposure to surgical emergencies.

Two months into their four month surgical rotation, FY1s completed an anonymous online survey that focused on their confidence in dealing with emergency surgical admissions. Working practice was then changed by the creation of a formal emergency foundation year one (FY1) rota, and the introduction of a baton bleep. The expectation was that all emergency admissions would be clerked by an FY1 doctor. The cohort were asked to repeat the survey after implementation of change.

Across all areas assessed, the confidence and experience of the junior doctors was improved. Initially 70% of FY1s felt exposure to emergency surgical cases was inadequate, falling to 0% after the intervention. This was associated with a rise in the average number of acute cases clerked by each FY1 per week from 1.2 to 4.0. At baseline, only 30% of those surveyed felt that they were gaining the skills and experience necessary to prepare them for an FY2 job in general surgery, and after the intervention this increased to 100%.

The increased pressures of service provision within reduced working hours does not necessitate the exclusion FY1 doctors from the assessment and management of surgical emergencies. We have demonstrated that preserving this exposure is a priority in the training of junior doctors, resulting in more experienced and confident medical staff.
CSF xanthochromia: correlation with brain imaging and its usefulness as an out-of-hours test
Authors: Ahmed Farhan , Gibbons Stephen , El-Kadiki Alia
Published: May 2014

Background

Subarachnoid haemorrhage (SAH) is a spontaneous bleed into the subarachnoid space which is investigated by CT head and cerebrospinal fluid (CSF) xanthochromia. The aim of this study was to compare CSF xanthochromia with brain imaging and evaluate the need for out of hours (OOH) testing for CSF xanthochromia.

Method

Discharge summaries and brain imaging of patients with positive xanthochromia screen were reviewed over 12 months retrospectively. Timings of CSF xanthochromia and hospital discharge of 30 consecutive patients with negative xanthochromia screen were also examined.

Results

From 289 xanthochromia requests, 23 were positive but only 2 patients had an actual bleed. In 30 consecutive negative xanthochromia results, all brain imaging results suggested no bleed. Eight of these requests were performed OOH, and as a result, 1 patient was discharged early.

Conclusions

CSF xanthochromia has a poor positive predictive value (8.7%) but has a good negative predictive value (100%) for SAH. Analysis of CSF xanthochromia OOH, in patients with negative CT head, did not speed up the discharge process from the hospital.
An Investigation on Quantum Dot Superlattice (QDSL) Diode
Authors: Chan Pik-Yiu , Lingalugari Murali , Heller Evan , Jain Faquir
Published: May 2014

A diode with a quantum dot superlattice on silicon has been reported. Step-wise features are shown in the diode output characteristic, which can be explained by the presence of mini-energy bands in the structure. The theory regarding quantum dot superlattice is also presented.
Designing Filtration Systems to Remove Heavy Metals from Water
Authors: Lombardo Andrew W. , Brigano Frank A.
Published: May 2014

The electronics industry uses high volumes of heavy metals in its production processes. Many of these heavy metals can end up in water and can be very difficult to remove due to the different forms that the heavy metal can exist in. Special design characteristics should be used to produce filters to remove heavy metals. In this study, we identify the different species of heavy metals and describe a method that has been tested for removing all types of species for heavy metals from water. This filtration technique utilizes multiple layers to ensure the removal of soluble, insoluble and complex species of heavy metals in water. The testing was done with a complex solution of lead according to NSF/American National Standards Institute (ANSI) standard 53 for the removal of lead at pH 8.5, using a combination of soluble, particulate and semi-insoluble lead. Filters were compared to standard, commercially available, gravity pitcher filters. The testing showed that the newly designed filter removed over 80 gallons of lead below the drinking water limit, compared to a standard filter which failed immediately. When trying to remove heavy metals from water, special care needs to be used in the design of the system to ensure the removal of all species of heavy metals.
Bekenstein–Hawking entropy in expanding universes from black hole theorems
Authors: Viaggiu Stefano
Published: May 2014

We show that the use of suitable theorems for black hole formation in Friedmann expanding universes leads to a modification of the Bekenstein–Hawking entropy. By adopting an argument similar to the original Bekenstein one, we write down the expression for the Bekenstein–Hawking entropy suitable for non-static isotropic expanding universes together with the equation of state of a black hole. This equation can be put in a form similar to the one of an ideal gas but with a factor depending on the Hubble radius. Moreover, we give some argument on a possible relation between our entropy expression and the Cardy–Verlinde one. Finally, we explore the possibility that primordial inflation is due to black hole evaporation in our context.
Numerical analysis of the terahertz multilayer metamaterials
Authors: Su Chao , He Xiaoyong , Li Rui , Cai Genwang , Fan Zhiqin , Wang Shijian
Published: May 2014

On the basis of transfer matrix method (TMM), the effective medium theories (EMT) which can be applied to the n-layer unit cell structures have been developed. By using this method, we have systematically investigated the influences of the structure parameters, operation frequency, and material gain on the dispersion properties and transmission of the metallic-dielectric stratified structure (MDSS) in the terahertz (THz) regime. The n-unit cell structures show much more freedom to study the MDSS. The results show that the dispersion relationship acquired from the EMT agrees well with those from the TMM when the value of kx is small. With the increase of the frequency, the n-layer unit cell MDSS can show more than one dip, and the dip positions can be changed by altering the doping concentration of the InSb layer. As the material gain increase, the transmission increases, and the full-width-half-maximum of the transmission spectrum decrease. This proposed method can also be applied to other spectral regions, such as microwave and infrared regimes. The results are beneficial to improve the performance of MDSSs devices and have great potential for many applications in fields of sub-wavelength image and superlens design.
Information leakage in quantum dialogue by using the two-qutrit entangled states
Authors: Gao Gan
Published: May 2014

In this paper [Mod. Phys. Lett. B23 (2009) 2993], Zhang and Zhan proposed a quantum dialogue protocol by using the two-qutrit entangled states. We study the security of the protocol and find that it is not secure. The eavesdropper can obtain half of secret messages without performing any attack. In other words, their quantum dialogue protocol has the drawback of information leakage.
Magnetic CoFe2O4/carbon nanotubes composites: fabrication, microstructure and magnetic response
Authors: Wang Panfeng , Xu Jingcai , Han Yanbing , Hong Bo , Jin Hongxiao , Jin Dingfeng , Peng Xiaoling , Li Jing , Ge Hongliang , Wang Xinqing
Published: May 2014

By combining the unique microstructure of carbon nanotubes (CNTs) with the good magnetism of CoFe 2 O 4 ferrites, CoFe 2 O 4/CNTs nanocomposites were prepared by the solvothermal method for the application of targeting therapy and tumor hyperthermia. X-ray diffraction (XRD), thermal gravity analysis (TGA), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM) were introduced to study the influence of the solvothermal temperature, time and the CNTs content on the microstructure and magnetic properties of CoFe 2 O 4/CNTs nanocomposites. The diameter of CoFe 2 O 4 nanoparticles coating on the surface of CNTs and the saturation magnetization (Ms) increased with the solvothermal temperature. CoFe 2 O 4/CNTs nanocomposites prepared at 180°C, 200°C and 220°C exhibited superparamagnetism at room temperature, while the samples prepared at 240°C and 260°C presented ferromagnetism. And the solvothermal time and CNTs content slightly affected the microstructure and magnetic properties, Ms and coercivity (Hc) increased slightly with the increasing solvothermal time and the decreasing CNTs content.
Antisymmetry breaking of discrete dipole gap solitons induced by a phase-slip defect
Authors: Zhang Xiangyu , Chai Jinglei , Ou Dezhao , Li Yongyao
Published: May 2014

In this paper, we study the antisymmetry breaking of discrete dipole soliton induced by a phase-slip one-dimensional discrete lattice, which contains on-site self-repulsive nonlinearity. This system can be realized in waveguide arrays system in optics or Bose–Einstein condensate in optical lattice. Different from the symmetry breaking occurring in the ground-state, antisymmetry breaking occurs in the first excited state, which contains antisymmetry. For this system, stable antisymmetric dipole soliton and anti-asymmetric are found, the symmetry transition between them is supercritical type. It is found that, increasing the total norm of the soliton or decreasing the coupled strength of the defect waveguide can lead to the antisymmetry breaking. Such kind of symmetry breaking can lead to the change of the tendency of some characters of the soliton.