bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seven new champion linear codes
Authors: Brown Gavin , Kasprzyk Alexander M. 
Published: May 2013

AbstractWe exhibit seven linear codes exceeding the current best known minimum distance $d$ for their dimension $k$ and block length $n$. Each code is defined over ${ \mathbb{F} }_{8} $, and their invariants $[n, k, d] $ are given by $[49, 13, 27] $, $[49, 14, 26] $, $[49, 16, 24] $, $[49, 17, 23] $, $[49, 19, 21] $, $[49, 25, 16] $ and $[49, 26, 15] $. Our method includes an exhaustive search of all monomial evaluation codes generated by points in the $[0, 5] \times [0, 5] $ lattice square.
Effects of the insertional and appositional forces of the canine diaphragm on the lower ribs
Authors: Wilson Theodore A. , De Troyer André 
Published: May 2013

Key points
Although the diaphragm causes a fall in pleural pressure, it expands the lower portion of the ribcage when it contracts.
This action is conventionally considered to be the result of two mechanisms, namely, the force applied by the muscle fibres on the ribs into which they insert (insertional force) and the transmission of abdominal pressure through the zone of apposition (appositional force).
In this study in anaesthetized dogs, we assessed the magnitude of the force exerted by the diaphragm on the lower ribs and the relative contributions of the insertional and appositional components.
The results show that, per unit pressure, the inspiratory effect of the diaphragmatic force on the lower ribs is equal to the expiratory effect of pleural pressure and that the insertional force contributes 60% of that inspiratory effect.
Abstract  The diaphragm has an inspiratory action on the lower ribs, and current conventional wisdom maintains that this action is the result of two mechanisms, namely, the force applied by the muscle fibres on the ribs into which they insert (insertional force) and the transmission of abdominal pressure through the zone of apposition (appositional force). The magnitude of the diaphragmatic force and the relative contributions of the insertional and appositional components, however, are unknown. To assess these forces, the inspiratory intercostal muscles in all interspaces were severed in anaesthetized dogs, so that the diaphragm was the only muscle active during inspiration, and the displacements of the lower ribs along the craniocaudal and laterolateral axes were measured during quiet breathing, during occluded breaths and during passive lung inflation. From these data, the isolated effects of pleural pressure and transdiaphragmatic pressure on rib displacement were determined. Then external forces were applied to the ribs in the cranial and the lateral direction to simulate, respectively, the effects of the insertional and appositional forces, and the rib trajectories for these external forces were used as the basis for a vector analysis to obtain the relative magnitudes of the insertional and appositional contributions to the rib displacement driven by transdiaphragmatic pressure. The results show that, per unit pressure, the inspiratory effect of the diaphragmatic force on the lower ribs is equal to the expiratory effect of pleural pressure, and that the insertional force contributes 60% of that inspiratory effect.
Doublet discharge stimulation increases sarcoplasmic reticulum Ca2+ release and improves performance during fatiguing contractions in mouse muscle fibres
Authors: Cheng Arthur J. , Place Nicolas , Bruton Joseph D. , Holmberg Hans‐Christer , Westerblad Håkan 
Published: May 2013

Key points
Motor neurons are frequently activated to give two action potentials at 200–300 Hz (doublets) at the onset of voluntary contractions. Doublets increase force and rate of force development.
During fatigue, decreased sarcoplasmic reticulum Ca2+ release and decreased myofibrillar Ca2+ sensitivity both contribute to the fatigue‐induced force loss. We studied whether electrically evoked doublets at contraction onset can counteract such fatigue‐induced changes. Experiments were performed using intact fast‐twitch and slow‐twitch single muscle fibres of mice.
In the unfatigued state, doublets induce increased sarcoplasmic reticulum Ca2+ release at the onset of contractions, which increases peak force and force–time integral. During fatigue induced by 150 repeated contractions, doublets markedly improve isometric force production during the first 25 contractions. At the end of fatigue, addition of doublets at contraction onset can temporarily increase force production.
Doublets are beneficial in that they improve contractile performance when added at any stage of strenuous activity, although the effect is largest in early fatigue stages.
Abstract  Double discharges (doublets) of motor neurones at the onset of contractions increase both force and rate of force development during voluntary submaximal contractions. The purpose of this study was to examine the role of doublet discharges on force and myoplasmic free [Ca2+] ([Ca2+]i) during repeated fatiguing contractions, using a stimulation protocol mimicking the in vivo activation pattern during running. Individual intact fibres from the flexor digitorum brevis muscle of mice were stimulated at 33°C to undergo 150 constant–frequency (five pulses at 70 Hz) or doublet (an initial, extra pulse at 200 Hz) contractions at 300 ms intervals. In the unfatigued state, doublet stimulation resulted in a transient (∼10 ms) approximate doubling of [Ca2+]i, which was accompanied by a greater force–time integral (∼70%) and peak force (∼40%) compared to constant frequency contractions. Moreover, doublets markedly increased force–time integral and peak force during the first 25 contractions of the fatiguing stimulation. In later stages of fatigue, addition of doublets increased force production but the increase in force production corresponded to only a minor portion of the fatigue‐induced reduction in force. In conclusion, double discharges at the onset of contractions effectively increase force production, especially in early stages of fatigue. This beneficial effect occurs without additional force loss in later stages of fatigue, indicating that the additional energy cost induced by doublet discharges to skeletal muscle is limited.
Maculatin 1.1 Disrupts Staphylococcus aureus Lipid Membranes via a Pore Mechanism
Authors: Sani M.-A. , Whitwell T. C. , Gehman J. D. , Robins-Browne R. M. , Pantarat N. , Attard T. J. , Reynolds E. C. , O'Brien-Simpson N. M. , Separovic F. 
Published: May 2013

ABSTRACT

Maculatin 1.1 (Mac1) showed potent activity against
Staphylococcus aureus
with an MIC of 7 μM. The mode of action of Mac1 was investigated by combining assays with
S. aureus
cells and lipid vesicles mimicking their membrane composition. A change in Mac1 conformation was monitored by circular dichroism from random coil to ca. 70% α-helix structure in contact with vesicles. Electron micrographs of
S. aureus
incubated with Mac1 showed rough and rippled cell surfaces. An uptake of 65% of small (FD, 4 kDa [FD-4]) and 35% of large (RD, 40 kDa [RD-40]) fluorescent dextrans by
S. aureus
was observed by flow cytometry and indicate that Mac1 formed a pore of finite size. In model membranes with both dyes encapsulated together, the full release of FD-4 occurred, but only 40% of RD-40 was reached, supporting the flow cytometry results, and indicating a pore size between 1.4 and 4.5 nm. Finally, solid-state nuclear magnetic resonance showed formation of an isotropic phase signifying highly mobile lipids such as encountered in a toroidal pore structure. Overall, Mac1 is a promising antimicrobial peptide with the potent capacity to form pores in
S. aureus
membranes.
Induction of Plasmid-Carried
qnrS1
in Escherichia coli by Naturally Occurring Quinolones and Quorum-Sensing Signal Molecules
Authors: Kwak Yee Gyung , Jacoby George A. , Hooper David C. 
Published: May 2013

ABSTRACT

Naturally occurring quinolone and quinolone-like compounds, such as quinine, 2-hydroxyquinoline, 4-hydroxyquinoline, and 2-heptyl-3-hydroxy-4(1H)-quinolone, increased expression of
qnrS1
in
Escherichia coli
2.3- to 11.2-fold, similar to the synthetic quinolone ciprofloxacin. In contrast, chromosomal
qnrVS1
of
Vibrio splendidus
was not induced by these compounds. Molecules associated with quorum sensing, such as
N
-3-hydroxybutyryl-homoserine lactone (HSL),
N
-hexanoyl-HSL, and
N
-3-(oxododecanoyl)-HSL, did not show an induction effect on either
qnrS1
or
qnrVS1
at the tested concentrations.
Coadministration of Atazanavir-Ritonavir and Zinc Sulfate: Impact on Hyperbilirubinemia and Pharmacokinetics
Authors: Moyle Graeme , Else Laura , Jackson Akil , Back David , Yapa Manisha H. , Seymour Natalia , Ringner-Nackter Lisa , Karolia Zeenat , Gazzard Brian , Boffito Marta 
Published: May 2013

ABSTRACT

Atazanavir (ATV) causes an elevation of unconjugated hyperbilirubinemia (HBR) as a result of UDP glucuronyltransferase (UGT) 1A1 inhibition. Zinc sulfate (ZnSO
4
) reduces unconjugated hyperbilirubinemia in individuals with Gilbert's syndrome. We assessed the changes in total, conjugated, and unconjugated bilirubin and the effect on ATV pharmacokinetics (PK) after single and 14-day dosing of ZnSO
4
. HIV patients, stable on ATV/ritonavir (ATV/r)-containing regimens with a total bilirubin level of >25mmol/liter received 125 mg daily of ZnSO
4
as Solvazinc tablets for 14 days. ATV/r and bilirubin concentrations were measured pre-ATV/r dose and 2, 4, 6, 8, and 24 h post-ATV/r dose; before ZnSO
4
initiation (phase 1), after a single dose (phase 2) and after 14 days (phase 3). Changes in bilirubin and ATV/r concentrations in the absence or presence of ZnSO
4
were evaluated by geometric mean ratios (GMRs) and 90% confidence intervals (CIs; we used phase 1 as a reference). Sixteen male patients completed the study maintaining virologic suppression; ZnSO
4
was well tolerated. Statistically significant declines in total bilirubin
C
max
and AUC
0–24
of 16 and 17% were seen in phase2 and 20% in phase 3. Although there were no significant changes in conjugated bilirubin, unconjugated bilirubin
C
max
and AUC
0–24
of were lower (17 and 19%, phase 2; 20 and 23% during phase 3). The ATV GMRs (90% CI) for
C
trough
,
C
max
, and AUC
0–24
were 0.74 (0.62 to 0.89), 0.82 (0.70 to 0.97), and 0.78 (0.70 to 0.88). Intake of ZnSO
4
decreases total and unconjugated bilirubin and causes modest declines in ATV exposure. ZnSO
4
supplementation may be useful in management of ATV-related HBR in selected patients.
Efficacy of AiiM, an
N
-Acylhomoserine Lactonase, against Pseudomonas aeruginosa in a Mouse Model of Acute Pneumonia
Authors: Migiyama Yohei , Kaneko Yukihiro , Yanagihara Katsunori , Morohoshi Tomohiro , Morinaga Yoshitomo , Nakamura Shigeki , Miyazaki Taiga , Hasegawa Hiroo , Izumikawa Koichi , Kakeya Hiroshi , Kohrogi Hirotsugu , Kohno Shigeru 
Published: May 2013

ABSTRACT

Quorum sensing (QS) in
Pseudomonas aeruginosa
regulates the production of many virulence factors and plays an important role in the pathogenesis of
P. aeruginosa
infection.
N
-acyl homoserine lactones (AHL) are major QS signal molecules. Recently, a novel AHL-lactonase enzyme, AiiM, has been identified. The aim of this study was to evaluate the effect of AiiM on the virulence of
P. aeruginosa
in a mouse model of acute pneumonia. We developed a
P. aeruginosa
PAO1 strain harboring an AiiM-expressing plasmid. The production of several virulence factors by the AiiM-expressing strain was examined. Mice were intratracheally infected with an AiiM-expressing PAO1 strain. Lung histopathology, bacterial burden, and bronchoalveolar lavage (BAL) fluid were assessed at 24 h postinfection. AiiM expression in PAO1 reduced production of AHL-mediated virulence factors and attenuated cytotoxicity against human lung epithelial cells. In a mouse model of acute pneumonia, AiiM expression reduced lung injury and greatly improved the survival rates. The levels of proinflammatory cytokines and myeloperoxidase activity in BAL fluid were significantly lower in mice infected with AiiM-expressing PAO1. Thus, AiiM can strongly attenuate
P. aeruginosa
virulence in a mammalian model and is a potential candidate for use as a therapeutic agent against
P. aeruginosa
infection.
Antibiotic Administration Routes Significantly Influence the Levels of Antibiotic Resistance in Gut Microbiota
Authors: Zhang Lu , Huang Ying , Zhou Yang , Buckley Timothy , Wang Hua H. 
Published: May 2013

ABSTRACT

This study examined the impact of oral exposure to antibiotic-resistant bacteria and antibiotic administration methods on antibiotic resistance (AR) gene pools and the profile of resistant bacteria in host gastrointestinal (GI) tracts using C57BL/6J mice with natural gut microbiota. Mice inoculated with a mixture of
tet
(M)-carrying
Enterococcus
spp. or
bla
CMY-2
-carrying
Escherichia coli
were treated with different doses of tetracycline hydrochloride (Tet) or ampicillin sodium (Amp) and delivered via either feed or intravenous (i.v.) injection. Quantitative PCR assessment of mouse fecal samples revealed that (i) AR gene pools were below the detection limit in mice without prior inoculation of AR gene carriers regardless of subsequent exposure to corresponding antibiotics; (ii) oral exposure to high doses of Tet and Amp in mice inoculated with AR gene carriers led to rapid enrichment of corresponding AR gene pools in feces; (iii) significantly less or delayed development of AR in the GI tract of the AR carrier-inoculated mice was observed when the same doses of antibiotics were administered via i.v. injection rather than oral administration; and (iv) antibiotic dosage, and maybe the excretion route, affected AR in the GI tract. The shift of dominant AR bacterial populations in the gut microbiota was consistent with the dynamics of AR gene pools. The emergence of endogenous resistant bacteria in the gut microbiota corresponding to drug exposure was also observed. Together, these data suggest that oral administration of antibiotics has a prominent effect on AR amplification and development in gut microbiota, which may be minimized by alternative drug administration approaches, as illustrated by i.v. injection in this study and proper drug selection.
Broad-Spectrum Antimalarial Activity of Peptido Sulfonyl Fluorides, a New Class of Proteasome Inhibitors
Authors: Tschan Serena , Brouwer Arwin J. , Werkhoven Paul R. , Jonker Anika M. , Wagner Lena , Knittel Sarah , Aminake Makoah Nigel , Pradel Gabriele , Joanny Fanny , Liskamp Rob M. J. , Mordmüller Benjamin 
Published: May 2013

ABSTRACT

Despite declining numbers of cases and deaths, malaria remains a major public health problem in many parts of the world. Today, case management relies heavily on a single class of antimalarial compounds: artemisinins. Hence, development of resistance against artemisinins may destroy current malaria control strategies. Beyond malaria control are elimination and eradication programs that will require drugs with good activity against acute infection but also with preventive and transmission-blocking properties. Consequently, new antimalarials are needed not only to ensure malaria control but also for elimination and eradication efforts. In this study, we introduce peptido sulfonyl fluorides (PSF) as a new class of compounds with antiplasmodial activity. We show that PSF target the plasmodial proteasome and act on all asexual stages of the intraerythrocytic cycle and on gametocytes. PSF showed activities at concentrations as low as 20 nM against multidrug-resistant and chloroquine-sensitive
Plasmodium falciparum
laboratory strains and clinical isolates from Gabon. Structural requirements for activity were identified, and cytotoxicity in human HeLa or HEK 293 cells was low. The lead PSF PW28 suppressed growth of
Plasmodium berghei
in vivo
but showed signs of toxicity in mice. Considering their modular structure and broad spectrum of activity against different stages of the plasmodial life cycle, proteasome inhibitors based on PSF have a great potential for further development as preclinical candidate compounds with improved species-specific activity and less toxicity.
Pseudomonas aeruginosa Uses Multiple Pathways To Acquire Iron during Chronic Infection in Cystic Fibrosis Lungs
Authors: Konings Anna F. , Martin Lois W. , Sharples Katrina J. , Roddam Louise F. , Latham Roger , Reid David W. , Lamont Iain L. 
Published: May 2013

ABSTRACT

Pseudomonas aeruginosa
chronically infects the lungs of more than 80% of adult patients with cystic fibrosis (CF) and is a major contributor to the progression of disease pathology.
P. aeruginosa
requires iron for growth and has multiple iron uptake systems that have been studied in bacteria grown in laboratory culture. The purpose of this research was to determine which of these are active during infection in CF. RNA was extracted from 149 sputum samples obtained from 23 CF patients. Reverse transcription–quantitative real-time PCR (RT-qPCR) was used to measure the expression of
P. aeruginosa
genes encoding transport systems for the siderophores pyoverdine and pyochelin, for heme, and for ferrous ions. Expression of
P. aeruginosa
genes could be quantified in 89% of the sputum samples. Expression of genes associated with siderophore-mediated iron uptake was detected in most samples but was at low levels in some samples, indicating that other iron uptake mechanisms are active. Expression of genes encoding heme transport systems was also detected in most samples, indicating that heme uptake occurs during infection in CF.
feoB
expression was detected in all sputum samples, implying an important role for ferrous ion uptake by
P. aeruginosa
in CF. Our data show that multiple
P. aeruginosa
iron uptake mechanisms are active in chronic CF infection and that RT-qPCR of RNA extracted from sputum provides a powerful tool for investigating bacterial physiology during infection in CF.
Shiga Toxin 2 Reduces Complement Inhibitor CD59 Expression on Human Renal Tubular Epithelial and Glomerular Endothelial Cells
Authors: Ehrlenbach Silvia , Rosales Alejandra , Posch Wilfried , Wilflingseder Doris , Hermann Martin , Brockmeyer Jens , Karch Helge , Satchell Simon C. , Würzner Reinhard , Orth-Höller Dorothea 
Published: May 2013

ABSTRACTInfections with enterohemorrhagicEscherichia coli(EHEC) are a primary cause of hemolytic-uremic syndrome (HUS). Recently, Shiga toxin 2 (Stx2), the major virulence factor of EHEC, was reported to interact with complement, implying that the latter is involved in the pathogenesis of EHEC-induced HUS. The aim of the present study was to investigate the effect of Stx2 on the expression of membrane-bound complement regulators CD46, CD55, and CD59 on proximal tubular epithelial (HK-2) and glomerular endothelial (GEnC) cells derived from human kidney cells that are involved in HUS. Incubation with Stx2 did not influence the amount of CD46 or CD55 on the surface of HK-2 and GEnC cells, as determined by fluorescence-activated cell sorter analysis. In contrast, CD59 was significantly reduced by half on GEnC cells, but the reduction on HK-2 cells was less pronounced. With increasing amounts of Stx2, reduction of CD59 also reached significance in HK-2 cells. Enzyme-linked immunosorbent assay analyses showed that CD59 was not present in the supernatant of Stx2-treated cells, implying that CD59 reduction was not caused by cleavage from the cell surface. In fact, reverse transcription-quantitative PCR analyses showed downregulation of CD59 mRNA as the likely reason for CD59 cell surface reduction. In addition, a significant increase in terminal complement complex deposition on HK-2 cells was observed after treatment with Stx2, as a possible consequence of CD59 downregulation. In summary, Stx2 downregulates CD59 mRNA and protein levels on tubular epithelial and glomerular endothelial cells, and this downregulation likely contributes to complement activation and kidney destruction in EHEC-associated HUS.
The Mesoproterozoic Rayner Province in the Lambert Glacier area: its age, origin, isotopic structure and implications for Australia–Antarctica correlations
Authors: Mikhalsky E. V. , Sheraton J. W. , Kudriavtsev I. V. , Sergeev S. A. , Kovach V. P. , Kamenev I. A. , Laiba A. A. 
Published: May 2013

Abstract

Within the Rayner Province in the Lambert Glacier area, two Proterozoic lithotectonic zones are distinguished, which differ in age and lithology. In the Fisher Zone, a significant juvenile component (ε
Nd
(
t
)=+2 to +4) is represented by mafic, intermediate and felsic plutonic and volcanic rocks; the tectonomagmatic processes were concentrated at
c.
1400–1200 Ma. In the Beaver Zone, orthogneisses record multiple emplacement, metamorphism and ductile deformation at
c.
1150–930 Ma. New U–Pb SHRIMP-II zircon ages (
c.
1140 Ma and 1095 Ma – protolith emplacement;
c.
950–850 and
c.
540 Ma – metamorphism), chemical and Sm–Nd isotopic data indicate that both zones have their continuations in the eastern Amery Ice shelf coast. The Rayner Province has some geological features in common with the Albany-Fraser Orogen in Western Australia, suggesting that these regions evolved in similar tectonic environments at
c.
1400–1300 Ma, followed by steady closure, from east to west, of the ocean that separated the Mawson Continent from Western Australia.

Supplementary material:

Chemical compositions of rocks, a summary of trace element ratios, a summary of published U–Pb dates, field photo views, new U–Pb analyses by SIMS SHRIMP-II and new Sm–Nd data are available at
www.geolsoc.org.uk/SUP18621
Possible armalcolite pseudomorph-bearing garnet–sillimanite gneiss from Skallevikshalsen, Lützow-Holm Complex, East Antarctica: Implications for ultrahigh-temperature metamorphism
Authors: Kawasaki Toshisuke , Adachi Tatsuro , Nakano Nobuhiko , Osanai Yasuhito 
Published: May 2013

Abstract

A possible armalcolite pseudomorph has been identified in garnet–sillimanite gneiss from Skallevikshalsen, located
c.
30 km NE of Rundvågshetta, in a terrane with the highest metamorphic grade in the Lützow-Holm Complex, East Antarctica. It occurs as an Fe–Mg–Ti compositional domain consisting of ilmenite, rutile and pseudorutile, partially mantled by rutile within ilmenite. The domain yields an average
X
Mg
of 0.171±0.036 exceeding by 3 wt% TiO
2
from armalcolite stoichiometry, while the analysis closest to armalcolite stoichiometry has an
X
Mg
value close to 0.202. Host ilmenite with 0.4 mol% hematite is in contact with prismatic sillimanite, quartz, plagioclase and K-feldspar.

In run products of annealing experiments performed to investigate the origin of the pseudomorph, armalcolite–ilmenite reaction coronae were developed around relict rutile in rock fragments of quartz eclogite from the Higashi-Akaishi mass of the Sanbagawa belt, central Shikoku, Japan. The experiments were carried out at 1 atm and 960–1050 °C with wüstite–magnetite buffer and imply a minimum temperature of 1290 °C for armalcolite stability when extrapolated to Skallevikshalsen pressures of 1.0 GPa. Mineral chemistry thermobarometry for Skallevikshalsen yields a metamorphic path with
P
–
T
peak conditions of 0.88–1.1 GPa and 970–1050 °C, followed by retrograde metamorphism at 0.6 GPa and 780 °C, and finally metasomatic alteration at
c.
630 °C. This
P
–
T
path matches that for similar ultrahigh-temperature metamorphic rocks from Rundvågshetta and Sri Lanka, and is markedly lower in temperature than the unreasonable estimates based on armalcolite stability. This discrepancy is inferred to reflect chemical impurities in armalcolite that lower its minimum temperature stability by more than 200 °C.