bluuebunny/crossref_metadata_2025 huggingface dataset:
How China's Holdings of Foreign Reserves Affect the Value of the US Dollar in Europe and Asia
Authors: Leightner Jonathan E.
Published: May 2010

By January 2009, China held almost US$2tn in foreign reserves. The present paper estimates the marginal effect of China changing its holdings of foreign reserves on the value of the US dollar in Europe and Asia. Because using traditional techniques to find this estimate would be inappropriate due to severe problems resulting from omitted variables, the present paper uses a new approach, bidirectional‐reiterative truncated projected least squares, that has been proven to minimize problems associated with omitted variables. It is found that if China would sell 1 percent of its foreign reserves, then the value of the US dollar would fall by 0.44 percent. With such a large effect, China has an incentive to either not sell any of its US dollar reserves or sell all of its US dollar reserves.
Sub‐lethal Photodynamic Damage to ARPE‐19 Cells Transiently Inhibits Their Phagocytic Activity†
Authors: Olchawa Magdalena , Szewczyk Grzegorz , Zaręba Mariusz , Piłat Anna , Bzowska Małgorzata , Mikołajczyk Tomasz , Sarna Tadeusz
Published: May 2010

Efficient phagocytosis of photoreceptor outer segments (POS) membranes by retinal pigment epithelium (RPE) plays a key role in biological renewal of these highly peroxidizable structures. Here, we tested whether photodynamic treatment, mediated by merocyanine 540 (MC 540), rose Bengal or a zinc‐substituted chlorophyllide inhibited phagocytic activity of ARPE‐19 cells in vitro. Specific phagocytosis of fluorescein‐5‐isothiocyanate‐labeled POS isolated from cow retinas and nonspecific phagocytosis of fluorescent polystyrene beads were measured by flow cytometry. Photodynamic treatment, mediated by all three photosensitizers with sub‐threshold doses, induced significant inhibition of the cell‐specific phagocytosis. The nonspecific phagocytosis was inhibited by photodynamic treatment mediated only by MC 540. The inhibition of phagocytosis was a reversible phenomenon and after 24 h, the photodynamically treated cells exhibited phagocytic activity that was comparable with that of untreated cells. This study provides proof of principle that sub‐threshold photodynamic treatment of ARPE‐19 cells with appropriate photosensitizers is a convenient experimental approach for in vitro study of the effects of oxidative stress on specific phagocytic activity of RPE cells. We postulate that oxidative damage to key components of the cell phagocytic machinery may be responsible for severe impairment of its activity, which can lead to retinal degeneration.
Sequenced RAPD markers to detect hybridization in the barbary partridge (Alectoris barbara, Phasianidae)
Authors: BARBANERA FILIPPO , GUERRINI MONICA , BERTONCINI FRANCO , CAPPELLI FABIO , MUZZEDDU MARCO , DINI FERNANDO
Published: May 2010

In the Alectoris partridges (Phasianidae), hybridization occurs occasionally as a result of the natural breakdown of isolating mechanisms but more frequently as a result of human activity. No genetic record of hybridization is known for the barbary partridge (A. barbara). This species is distributed mostly in North Africa and, in Europe, on the island of Sardinia (Italy) and on Gibraltar. The risk of hybridization between barbary and red‐legged partridge (A. rufa: Iberian Peninsula, France, Italy) is high in Sardinia and in Spain. We developed two random amplified polymorphic DNA (RAPD) markers to detect A. barbara × A. rufa hybrid partridges. We tested them on 125 experimental hybrids, sequenced the relative species‐specific bands and found that the bands and their corresponding sequences were reliably transmitted through a number of generations (F1, F2, F3, BC1, BC2). Our markers represent a highly valuable tool for the preservation of the A. barbara genome from the pressing threat of A. rufa pollution.
Detecting an impact of predation on bird populations depends on the methods used to assess the predators
Authors: Nicoll Malcolm , Norris Ken
Published: May 2010

1. In recent decades there have been population declines of many UK bird species, which have become the focus of intense research and debate. Recently, as the populations of potential predators have increased there is concern that increased rates of predation may be contributing to the declines. In this review, we assess the methodologies behind the current published science on the impacts of predators on avian prey in the UK.

2. We identified suitable studies, classified these according to study design (experimental/observational) and assessed the quantity and quality of the data upon which any variation in predation rates was inferred. We then explored whether the underlying study methodology had implications for study outcome.

3. We reviewed 32 published studies and found that typically observational studies comprehensively monitored significantly fewer predator species than experimental studies. Data for a difference in predator abundance from targeted (i.e. bespoke) census techniques were available for less than half of the 32 predator species studied.

4. The probability of a study detecting an impact on prey abundance was strongly, positively related to the quality and quantity of data upon which the gradient in predation rates was inferred.

5. The findings suggest that if a study is based on good quality abundance data for a range of predator species then it is more likely to detect an effect than if it relies on opportunistic data for a smaller number of predators.

6. We recommend that the findings from studies which use opportunistic data, for a limited number of predator species, should be treated with caution and that future studies employ bespoke census techniques to monitor predator abundance for an appropriate suite of predators.
An evidence‐based approach to equine parasite control: It ain't the 60s anymore
Authors: Kaplan R. M. , Nielsen M. K.
Published: May 2010

Most veterinarians continue to recommend anthelmintic treatment programmes for horses that derive from knowledge and concepts more than 40 years old. However, much has changed since these recommendations were first introduced and current approaches routinely fail to provide optimal or even adequate levels of parasite control. There are many reasons for this. Recent studies demonstrate that anthelmintic resistance in equine parasites is highly prevalent and multiple‐drug resistance is common in some countries, but few veterinarians take this into account when making treatment decisions or when recommending rotation of anthelmintics. Furthermore, the current approach of treating all horses at frequent intervals was designed specifically to control the highly pathogenic large strongyle,Strongylus vulgaris. But this parasite is now quite uncommon in managed horses in most of the world. Presently, the cyathostomins (small strongyles) are the principal parasitic pathogens of mature horses. The biology and pathogenesis of cyathostomins andS. vulgarisare very different and therefore require an entirely different approach. Furthermore, it is known that parasites are highly over‐dispersed in hosts, such that a small percentage of hosts harbour most of the parasites. The common practices of recommending the same treatment programme for all horses despite great differences in parasite burdens, recommending prophylactic treatment of all horses without indication of parasitic disease or knowing what species of parasites are infecting the horses, recommending use of drugs without knowledge of their efficacy and failing to perform diagnostic (faecal egg count) surveillance for estimating parasite burdens and determining treatment efficacy, are all incompatible with current standards of veterinary practice. Consequently, it is necessary that attitudes and approaches to parasite control in horses undergo a complete overhaul. This is best achieved by following an evidence‐based approach that takes into account all of these issues and is based on science, not tradition.
A new role for bicarbonate secretion in cervico‐uterine mucus release
Authors: Muchekehu Ruth W. , Quinton Paul M.
Published: May 2010

Cervical mucus thinning and release during the female reproductive cycle is thought to rely mainly on fluid secretion. However, we now find that mucus released from the murine reproductive tract critically depends upon concurrent bicarbonate (HCO3−) secretion. Prostaglandin E2(PGE2)‐ and carbachol‐stimulated mucus release was severely inhibited in the absence of serosal HCO3−, HCO3−transport, or functional cystic fibrosis transmembrane conductance regulator (CFTR). In contrast to mucus release, PGE2‐ and carbachol‐stimulated fluid secretion was not dependent on bicarbonate or on CFTR, but was completely blocked by niflumic acid. We found stimulated mucus release was severely impaired in the cystic fibrosis ΔF508 reproductive tract, even though stimulated fluid secretion was preserved. Thus, CFTR mutations and/or poor bicarbonate secretion may be associated with reduced female fertility associated with abnormal mucus and specifically, may account for the increased viscosity and lack of cyclical changes in cervical mucus long noted in women with cystic fibrosis.
Determinants of the induction of cortical plasticity by non‐invasive brain stimulation in healthy subjects
Authors: Ridding M. C. , Ziemann U.
Published: May 2010

The ability to induce cortical plasticity with non‐invasive brain stimulation (NBS) techniques has provided novel and exciting opportunities for examining the role of the human cortex during a variety of behaviours. Additionally, and importantly, the induction of lasting changes in cortical excitability can, under some conditions, reversibly modify behaviour and interact with normal learning. Such findings have driven a large number of recent studies examining whether by using such approaches it might be possible to induce functionally significant changes in patients with a large variety of neurological and psychiatric conditions including stroke, Parkinson's disease and depression. However, even in neurologically normal subjects the variability in the neurophysiological and behavioural response to such brain stimulation techniques is high. This variability at present limits the therapeutic usefulness of these techniques. The cause of this variability is multifactorial and to some degree still unknown. However, a number of factors that can influence the induction of plasticity have been identified. This review will summarise what is known about the causes of variability in healthy subjects and propose additional factors that are likely to be important determinants. A greater understanding of these determinants is critical for optimising the therapeutic applications of non‐invasive brain stimulation techniques.
Design of a Lab-Scale Rotary Cavity-Type Solar Reactor for Continuous Thermal Dissociation of Volatile Oxides Under Reduced Pressure
Authors: Chambon Marc , Abanades Stéphane , Flamant Gilles
Published: May 2010

A high-temperature lab-scale solar reactor prototype was designed, constructed and operated, allowing continuous ZnO thermal dissociation under controlled atmosphere at reduced pressure. It is based on a cavity-type rotating receiver absorbing solar radiation and composed of standard refractory materials. The reactant oxide powder is injected continuously inside the cavity and the produced particles (Zn) are recovered in a downstream ceramic filter. Dilution/quenching of the product gases with a neutral gas yields Zn nanoparticles by condensation. The solar thermal dissociation of ZnO was experimentally achieved, the reaction yields were quantified, and a first concept of solar reactor was qualified. The maximum yield of particles recovery in the filter was 21% and the dissociation yield was up to 87% (Zn weight content in the final powder) for a 5 NL/min neutral gas flow-rate (typical dilution ratio of 300).
Durability of Dye-Sensitized Solar Cells and Modules
Authors: Kitamura Takayuki , Okada Kenichi , Matsui Hiroshi , Tanabe Nobuo
Published: May 2010

It was investigated that the intrusion of water into the electrolyte was the most critical reason for the low stability of a dye-sensitized solar cell. To prevent the water intrusion, robust solar cells and submodules with a novel protection layer of metal circuit and tightly sealing package was developed. The excellent stability of the cell with ionic liquid electrolyte at high temperature conditions was also reveled. The resulting cell employing noble construction and ionic liquid electrolyte showed an extremely high stability to pass several endurance tests standardized in JIS for the stability of the photovoltaic submodule.
Development of Reactive Ceramics for Conversion of Concentrated Solar Heat Into Solar Hydrogen With Two-Step Water-Splitting Reaction
Authors: Kaneko H. , Taku S. , Naganuma Y. , Ishihara T. , Hasegawa N. , Tamaura Y.
Published: May 2010

The reactive ceramics suitable for the rotary-type solar reactor (proposed by Tokyo Institute of Technology, Tokyo) with two-step water-splitting reaction were developed. It is confirmed that O2 gas is evolved in the two-step water-splitting reaction with the reactive ceramics vigorously by rapid heating (α-O2-releasing reaction). The α-O2-releasing reaction is due to the formation of interstitial defect and the conversion of lattice oxygen into O2 gas at a nonequilibrium state. Reactive ceramics (NiFe2O4 and yttria stabilized zirconia (YSZ)-NiFe2O4 solid solution) can absorb solar thermal energy and convert thermal energy into chemical energy under high O2 partial pressure atmosphere in the α-O2-releasing reaction. Repetitive evolutions of O2 gas were observed in the two-step water-splitting reaction with YSZ-Fe3O4 solid solution and cerium based metal oxides (CeO2–NiO, CeO2–ZrO2, and CeO2–Ta2O5) at high O2 partial pressure. The CeO2–Ta2O5(Ce:Ta=90:10) released a large amount of O2 gas (3.95 cm3/g) in the α-O2 releasing reaction in the flow of air.
Design of dc/dc Converters for DMPPT PV Applications Based on the Concept of Energetic Efficiency
Authors: Adinolfi G. , Femia N. , Petrone G. , Spagnuolo G. , Vitelli M.
Published: May 2010

Distributed maximum power point tracking (DMPPT) is one of the most promising solutions to overcome the drawbacks associated with mismatching phenomena in photovoltaic (PV) applications. DMPPT is based on the adoption of a dc/dc converter dedicated to each PV module. The design of the power stage of such a converter is a challenging task because of the very high efficiency requirements and of the continuous changes of the operating point during the day, depending on the sun irradiation conditions. In this paper the guidelines for the design of dc-dc converters for DMPPT applications are presented and discussed.
Development of a Thermal Energy Storage System for Parabolic Trough Power Plants With Direct Steam Generation
Authors: Laing Doerte , Bauer Thomas , Lehmann Dorothea , Bahl Carsten
Published: May 2010

For future parabolic trough plants direct steam generation in the absorber pipes is a promising option for reducing the costs of solar thermal power generation. These new solar thermal power plants require innovative storage concepts, where the two-phase heat transfer fluid poses a major challenge. A three-part storage system is proposed where a phase change material (PCM) storage will be deployed for the two-phase evaporation, while concrete storage will be used for storing sensible heat, i.e., for preheating of water and superheating of steam. A pinch analysis helps to recognize interface constraints imposed by the solar field and the power block and describes a way to dimension the latent and sensible components. Laboratory test results of a PCM test module with ∼140 kgNaNO3, applying the sandwich concept for enhancement of heat transfer, are presented, proving the expected capacity and power density. The concrete storage material for sensible heat was improved to allow the operation up to 500°C for direct steam generation. A storage system with a total storage capacity of ∼1 MWh is described, combining a PCM module and a concrete module, which will be tested in 2009 under real steam conditions around 100 bars.
Identification of a Novel Transposon (Tn
6072
) and a Truncated Staphylococcal Cassette Chromosome
mec
Element in Methicillin-Resistant
Staphylococcus aureus
ST239
Authors: Chen Liang , Mediavilla José R. , Smyth Davida S. , Chavda Kalyan D. , Ionescu Ramona , Roberts Richard B. , Robinson D. Ashley , Kreiswirth Barry N.
Published: May 2010

A novel composite transposon (Tn
6072
) resembling staphylococcal cassette chromosome
mercury
(SCC
Hg
) was identified in a collection of sequence type (ST) 239 methicillin (meticillin)-resistant
Staphylococcus aureus
(MRSA) isolates from Romanian hospitals. Tn
6072
is homologous to the 5′ region of SCC
Hg
found in staphylococcal cassette chromosome
mec
(SCC
mec
) type III prototype strain 85/2082 but lacks the characteristic
mer
operon. SCC
Hg
has previously been reported to integrate downstream of
orfX
, at the same chromosomal location as SCC
mec
. Tn
6072
, by contrast, is demarcated by two IS
431
elements, flanked by 8-bp direct repeats, and inserted upstream of the origin of replication, within an open reading frame homologous to SAR2700 of
S. aureus
strain MRSA252. Analysis of a geographically and temporally diverse collection of 111 strains from the ST239 clonal group uncovered 11 additional strains harboring Tn
6072
, demonstrating a lineage-specific insertion pattern. Complete sequence analysis of the SCC
mec
regions of two representative Romanian strains (BK16704, BK16691) revealed two additional novel structures derived from a type III SCC
mec
background. BK16704 possesses an SCC
mec
3A.1.4 structure, with an IS
256
insertion downstream of the right chromosomal junction. In contrast, the SCC
mec
element of BK16691 is truncated downstream of the
mec
gene complex, with a 24-kb deletion encompassing the right chromosomal junction and an inverted downstream IS
256
element. This structure, tentatively named “ψSCC
mec
16691
,” confers methicillin resistance but lacks most of the J1/J2 region, including the
ccr
gene complex. Taken together, these findings provide evidence for the continuing evolution of SCC elements, as well as the ST239 clonal group.
In Vitro
and
In Vivo
Activities of Arachidonic Acid against
Schistosoma mansoni
and
Schistosoma haematobium
Authors: El Ridi Rashika , Aboueldahab Marwa , Tallima Hatem , Salah Mohamed , Mahana Noha , Fawzi Samia , Mohamed Shadia H. , Fahmy Omar M.
Published: May 2010

The development of arachidonic acid (ARA) for treatment of schistosomiasis is an entirely novel approach based on a breakthrough discovery in schistosome biology revealing that activation of parasite tegument-bound neutral sphingomyelinase (nSMase) by unsaturated fatty acids, such as ARA, induces exposure of parasite surface membrane antigens to antibody binding and eventual attrition of developing schistosomula and adult worms. Here, we demonstrate that 5 mM ARA leads to irreversible killing of ex vivo 1-, 3-, 4-, 5-, and 6-week-old
Schistosoma mansoni
and 9-, 10-, and 12-week-old
Schistosoma haematobium
worms within 3 to 4 h, depending on the parasite age, even when the worms were maintained in up to 50% fetal calf serum. ARA-mediated worm attrition was prevented by nSMase inhibitors, such as CaCl
2
and GW4869. Scanning and transmission electron microscopy revealed that ARA-mediated worm killing was associated with spine destruction, membrane blebbing, and disorganization of the apical membrane structure. ARA-mediated
S. mansoni
and
S. haematobium
worm attrition was reproduced
in vivo
in a series of 6 independent experiments using BALB/c or C57BL/6 mice, indicating that ARA in a pure form (Sigma) or included in infant formula (Nestle) consistently led to 40 to 80% decrease in the total worm burden. Arachidonic acid is already marketed for human use in the United States and Canada for proper development of newborns and muscle growth of athletes; thus, ARA has potential as a safe and cost-effective addition to antischistosomal therapy.
A Novel Polymyxin Derivative That Lacks the Fatty Acid Tail and Carries Only Three Positive Charges Has Strong Synergism with Agents Excluded by the Intact Outer Membrane
Authors: Vaara Martti , Siikanen Osmo , Apajalahti Juha , Fox John , Frimodt-Møller Niels , He Hui , Poudyal Anima , Li Jian , Nation Roger L. , Vaara Timo
Published: May 2010

Polymyxins are cationic lipopeptides (five cationic charges) and the last resort for the treatment of serious Gram-negative infections caused by multiresistant strains. NAB741 has a cyclic peptide portion identical to that of polymyxin B but carries in the linear peptide portion a threonyl-d-serinyl residue (no cationic charges) instead of the diaminobutyryl-threonyl-diaminobutyryl residue (two cationic charges). At the N terminus of the peptide, NAB741 carries an acetyl group instead of a mixture of methyl octanoyl and methyl heptanoyl residues. NAB741 sensitizedEscherichia coli,Klebsiella pneumoniae,Enterobacter cloacae, andAcinetobacter baumanniito antibiotics against which the intact outer membrane is an effective permeability barrier. When tested by using Etest strips on plates containing increasing concentrations of NAB741, the fractional inhibition concentration index (FICI) of the combination of NAB741 with rifampin ranged from ≤0.111 to 0.158 and that with clarithromycin from ≤0.094 to 0.292. When tested by the checkerboard method, the corresponding FICI values againstE. coliATCC 25922 were ≤0.141 to ≤0.155 with rifampin and 0.094 with clarithromycin. In addition, at 4 μg/ml, NAB741 decreased the MICs of azithromycin, mupirocin, fusidic acid, and vancomycin forE. colistrains andE. cloacaeby factors ranging from 8 to 200. A sister peptide, NAB752, carrying a threonyl-aminobutyryl residue as the linear peptide portion, was inactive. Furthermore, NAB741 sensitizedE. colito the bactericidal activity of fresh guinea pig serum. The renal clearance of NAB741 was approximately 400-fold, 16-fold, and 8-fold higher than those measured for colistin, NAB7061, and NAB739, respectively.
Meropenem Dosing in Critically Ill Patients with Sepsis Receiving High-Volume Continuous Venovenous Hemofiltration
Authors: Bilgrami I. , Roberts J. A. , Wallis S. C. , Thomas J. , Davis J. , Fowler S. , Goldrick P. B. , Lipman J.
Published: May 2010

Use of high ultrafiltrate flow rates with continuous venovenous hemofiltration (CVVHF) in critically ill patients is an emerging setting, for which there are few data to guide drug dosing. The objectives of this study were, firstly, to investigate the pharmacokinetics of meropenem in critically ill patients with severe sepsis who are receiving high-volume CVVHF with high-volume exchanges (≥4 liters/h); secondly, to determine whether standard dosing regimens (1,000 mg intravenously [i.v.] every 8 h) are sufficient for treatment of less susceptible organisms such as
Burkholderia pseudomallei
(MIC, 4 mg/liter); and, finally, to compare the clearances observed in this study with data from previous studies using lower-volume exchanges (1 to 2 liters/h). We recruited 10 eligible patients and collected serial pre- and postfilter blood samples and ultrafiltrate and urine samples. A noncompartmental method was used to determine meropenem pharmacokinetics. The cohort had a median age of 56.6 years, a median weight of 70 kg, and a median APACHE II (acute physiology and chronic health evaluation) score of 25. The median (interquartile range) values for meropenem were as follows: terminal elimination half-life, 4.3 h (2.9 to 6.0); terminal volume of distribution, 0.2 liters/kg (0.2 to 0.3); trough concentration, 7.7 mg/liter (6.2 to 12.9); total clearance, 6.0 liters/h (5.2 to 6.2); hemofiltration clearance, 3.5 liters/h (3.4 to 3.9). In comparing the meropenem clearance here with those in previous studies, ultrafiltration flow rate was found to be the parameter that accounted for the differences in clearance of meropenem (
R
2
= 0.89). In conclusion, high-volume CVVHF causes significant clearance of meropenem, necessitating steady-state doses of 1,000 mg every 8 h to maintain sufficient concentrations to treat less susceptible organisms such as
B. pseudomallei
.
First Detection of CTX-M and SHV Extended-Spectrum β-Lactamases in
Escherichia coli
Urinary Tract Isolates from Dogs and Cats in the United States
Authors: O'Keefe Alexandra , Hutton Tabitha A. , Schifferli Dieter M. , Rankin Shelley C.
Published: May 2010

One hundred fifty canine and feline
Escherichia coli
isolates associated with urinary tract infections were screened for the presence of extended-spectrum β-lactamase (ESBL) genes. Out of 60 isolates suspected to be ESBL positive based on antimicrobial susceptibility testing, 11 ESBLs were identified, including one SHV-12 gene, one CTX-M-14 gene, and nine CTX-M-15 genes. This study provides the first report of CTX-M- and SHV-type ESBLs in dogs and cats in the United States.
Cysteamine, the Molecule Used To Treat Cystinosis, Potentiates the Antimalarial Efficacy of Artemisinin
Authors: Min-Oo Gundula , Fortin Anny , Poulin Jean-François , Gros Philippe
Published: May 2010

Malaria continues to be a major threat to global health. Artemisinin combination therapy (ACT) is the recommended treatment for clinical malaria; however, recent reports of parasite resistance to artemisinin in certain areas where malaria is endemic have stressed the need for developing more efficacious ACT. We report that cysteamine (Cys), the aminothiol used to treat nephropathic cystinosis in humans, strongly potentiates the efficacy of artemisinin against thePlasmodiumparasitein vivo. Using a mouse model of infection withPlasmodium chabaudiAS, we observe that Cys dosing used to treat cystinosis in humans can strongly potentiate (by 3- to 4-fold) the antimalarial properties of the artemisinin derivatives artesunate and dihydroartemisinin. Addition of Cys to suboptimal doses of artemisinin delays the appearance of blood parasitemia, strongly reduces the extent of parasite replication, and significantly improves survival in a model of lethalP. chabaudiinfection. Cys, the natural product of the enzyme pantetheinase, has a history of safe use for the clinical management of cystinosis. Our findings suggest that Cys could be included in novel ACTs to improve efficacy againstPlasmodiumparasite replication, including artemisinin-resistant isolates. Future work will include clinical evaluation of novel Cys-containing ACTs and elucidation of the mechanism underlying the potentiation effect of Cys.
Effect on Human Cells of Environmental
Vibrio parahaemolyticus
Strains Carrying Type III Secretion System 2
Authors: Caburlotto Greta , Lleò Maria M. , Hilton Tamara , Huq Anwar , Colwell Rita R. , Kaper James B.
Published: May 2010

Vibrio parahaemolyticus
is an inhabitant of estuarine and marine environments that causes seafood-borne gastroenteritis worldwide. Recently, a type 3 secretion system (T3SS2) able to secrete and translocate virulence factors into the eukaryotic cell has been identified in a pathogenicity island (VP-PAI) located on the smaller chromosome. These virulence-related genes have previously been detected only in clinical strains. Classical virulence genes for this species (
tdh
,
trh
) are rarely detected in environmental strains, which are usually considered to lack virulence potential. However, during screening of a collection of environmental
V. parahaemolyticus
isolates obtained in the North Adriatic Sea in Italy, a number of marine strains carrying virulence-related genes, including genes involved in the T3SS2, were detected. In this study, we investigated the pathogenic potential of these marine
V. parahaemolyticus
strains by studying their adherence ability, their cytotoxicity, their effect on zonula occludin protein 1 (ZO-1) of the tight junctions, and their effect on transepithelial resistance (TER) in infected Caco-2 cells. By performing a reverse transcription-PCR, we also tested the expression of the T3SS2 genes
vopT
and
vopB2
, encoding an effector and a translocon protein, respectively. Our results indicate that, similarly to clinical strains, marine
V. parahaemolyticus
strains carrying
vopT
and
vopB2
and that other genes included in the VP-PAI are capable of adhering to human cells and of causing cytoskeletal disruption and loss of membrane integrity in infected cells. On the basis of data presented here, environmental
V. parahaemolyticus
strains should be included in coastal water surveillance plans, as they may represent a risk for human health.
Intramolecular Interactions between the Protease and Structural Domains Are Important for the Functions of Serine Protease Autotransporters
Authors: Tsang Casey , Malik Huma , Nassman Deana , Huang Antony , Tariq Fayha , Oelschlaeger Peter , Stathopoulos Christos
Published: May 2010

Autotransporter (AT) is a protein secretion pathway found in Gram-negative bacteria featuring a multidomain polypeptide with a signal sequence, a passenger domain, and a translocator domain. An AT subfamily named serine protease ATs of the family
Enterobacteriaceae
(SPATEs) is characterized by the presence of a conserved serine protease motif in the passenger domain which contributes to bacterial pathogenesis. The goal of the current study is to determine the importance of the passenger domain conserved residues in the SPATE proteolytic and adhesive functions using the temperature-sensitive hemagglutinin (Tsh) protein as our model. To begin, mutations of 21 fully conserved residues in the four passenger domain conserved motifs were constructed by PCR-based site-directed mutagenesis. Seventeen mutants exhibited a wild-type secretion level; among these mutants, eight displayed reduced proteolytic activities in Tsh-specific oligopeptide and mucin cleavage assays. These eight mutants also demonstrated lower affinities to extracellular matrix proteins, collagen IV, and fibronectin. These eight conserved residues were analyzed by molecular graphics modeling to demonstrate their intramolecular interactions with the catalytic triad and other key residues. Additional mutations were made to confirm the above interactions in order to demonstrate their significance to the SPATE functions. Altogether our data suggest that certain conserved residues in the SPATE passenger domain are important for both the proteolytic and adhesive activities of SPATE by maintaining the proper protein structure via intramolecular interactions between the protease and β-helical domains. Here, we provide new insight into the structure-function relationship of the SPATEs and the functional roles of their conserved residues.
Staphylococcal Superantigen-Like Protein 5 Inhibits Matrix Metalloproteinase 9 from Human Neutrophils
Authors: Itoh Saotomo , Hamada Eri , Kamoshida Go , Takeshita Kana , Oku Teruaki , Tsuji Tsutomu
Published: May 2010

Staphylococcal superantigen-like proteins (SSLs) constitute a family of exoproteins exhibiting structural similarities to superantigens and enterotoxins but no superantigenic activity. In this article, we present evidence that SSL5 specifically binds to matrix metalloproteinase 9 (MMP-9) and inhibits its enzymatic activity. When human neutrophil cell lysate was applied to recombinant His-tagged SSL5 conjugated to Sepharose, the bound fraction gave a major band of approximately 100 kDa in SDS-polyacrylamide gel electrophoresis. This protein was identified as the proform of MMP-9 (proMMP-9) by peptide mass fingerprinting analysis. The recombinant SSL5-Sepharose also bound to proMMP-9 secreted by interleukin 8 (IL-8)-stimulated neutrophils and HT1080 fibrosarcoma cells. Surface plasmon resonance analysis revealed that recombinant SSL5 bound to proMMP-9 with rather high affinity (dissociation constant [KD] = 1.9 nM). Recombinant SSL5 was found to effectively inhibit MMP-9-catalyzed hydrolysis of gelatin and a synthetic fluorogenic peptide in a noncompetitive manner (Ki= 0.097 nM), as assessed by zymography and the fluorescence quenching method. Finally, the transmigration of neutrophils across Matrigel basement membranes in response toN-formyl-methionyl-leucyl-phenylalanine (FMLP) was suppressed by the presence of recombinant SSL5. We discuss possible roles that SSL5 may play in immune evasion of staphylococci by inhibiting MMP and interfering with leukocyte trafficking.
The
Staphylococcus aureus
Epidermal Cell Differentiation Inhibitor Toxin Promotes Formation of Infection Foci in a Mouse Model of Bacteremia
Authors: Munro Patrick , Benchetrit Maxime , Nahori Marie-Anne , Stefani Caroline , Clément René , Michiels Jean-François , Landraud Luce , Dussurget Olivier , Lemichez Emmanuel
Published: May 2010

Inactivation of the host GTPase RhoA by staphylococcal epidermal cell differentiation inhibitor (EDIN) exotoxins triggers the formation of large transcellular tunnels, named macroapertures, in endothelial cells. We used bioluminescent strains of
Staphylococcus aureus
to monitor the formation of infection foci during the first 24 h of hematogenous bacterial dissemination. Clinically derived EDIN-expressing
S. aureus
strains S25 and Xen36 produced many disseminated foci. EDIN had no detectable impact on infection foci in terms of histopathology or the intensity of emitted light. Moreover, EDIN did not modify the course of bacterial clearance from the bloodstream. In contrast, we show that EDIN expression promotes a 5-fold increase in the number of infection foci produced by Xen36. This virulence activity of EDIN requires RhoA ADP-ribosyltranferase activity. These results suggest that EDIN is a risk factor for
S. aureus
dissemination through the vasculature by virtue of its ability to promote the formation of infection foci in deep-seated tissues.
The Oligosaccharide of Gonococcal Lipooligosaccharide Contains Several Epitopes That Are Recognized by Human Antibodies
Authors: Yamasaki Ryohei , Yabe Uichirou , Kataoka Chikako , Takeda Ushio , Asuka Shunpei
Published: May 2010

Recently, we isolated human IgG from normal human sera (NHS) using lipooligosaccharide (LOS) from gonococcal strain JW31R as an affinity ligand. We provided evidence that the oligosaccharide (OS) moiety of LOS was immunogenic in humans and that NHS contains functional antibodies that bind to the branched OS. The present study aimed to identify bactericidal antibodies that bind to partial core OS structures or their adjacent sites expressed in the 3,4-branched and 2,3:3,4-dibranched neisserial LOSs. Using 15253 LOS from serum-resistant gonococcal strain 15253 as an affinity ligand, we isolated IgG2 and found that this preparation contained at least three different species. (i) One IgG2 species recognized a cross-reactive epitope that is expressed on 3,4-branched and 2,3:3,4-dibranched neisserial LOSs. (ii) Another IgG2 species was specific for JW31R LOS from a pyocin-resistant gonococcal strain; this IgG-defined epitope was not shared with the aforementioned branched LOSs. (iii) The third IgG2 species bound to the “
Salmonella
minnesota
” Rb and Re mutant lipopolysaccharides (LPSs); this IgG2 recognizes a KDOα2-4KDO residue at the reducing end of the carbohydrate moiety of each LPS. The IgG2 was also found to be functional and facilitated the killing of strain 15253. The current results show that neisserial LOS contains several epitopes within its OS moiety that are recognized by human antibodies.
Diffusion of oligomers in latex systems — A route to low volatile organic compound (VOC) coatings
Authors: Fasano David M. , Fitzwater Susan J. , Lau Willie , Sheppard Aurelia C.
Published: May 2010

We synthesize specially designed latex polymer systems by an in situ emulsion polymerization process that yields latex particles with both a high molecular weight polymer phase and a low molecular weight oligomer phase. The oligomer functions as a plasticizer by lowering the glass transition temperature (Tg) of the polymer. A polymer system is prepared by blending soft latex and a hard latex where the hard mode consists of a hard, high molecular weight polymer and an oligomer, allowing for facile film formation at ambient conditions. Upon the soft and hard particles coming into contact during the film formation process, the oligomer preferentially diffuses from the hard polymer to the soft polymer, thus recovering the natural Tg of the hard polymer as described in a recent patent application. Oligomer diffusion allows a hard coalesced phase to be incorporated into a latex film without using a coalescing solvent, which would contribute to the volatile organic compound (VOC) content. A well-coalesced hard phase in a latex film contributes to a variety of desirable coatings properties, such as tack, print, block, and scrub resistance properties.
ESR analysis of the oxidation reactions of phosphorus-containing nitrone-type spin traps with gold(III) ion
Authors: Nakajima Akira , Matsuda Emiko , Ueda Yuto , Tajima Kunihiko
Published: May 2010

Phosphorus-containing cyclic nitrones, such as DEPMPO, CYPMPO, and DPPMPO, were oxidized by hydrogen tetrachloroaurate(III) to DEPMPOX, CYPMPOX, and DPPMPOX with the precipitation of Au(0). The reaction was depressed by the addition of chloride or hydroxide ions. The peculiar pH dependency was observed in DEPMPOX, CYPMPOX, and DPPMPOX formation, which should be caused by the diethoxyphosphoryl group in DEPMPO, the 1,3-propoxy cyclophosphoryl group in CYPMPO, and the diphenylphosphinoyl group in DPPMPO. The oxidation of the nitrones proceeded through the ligand exchange of Cl– in AuCl4– with >N+–O– in nitrone and the nucleophilic addition of the water molecule to the C-2 position in the nitrones, the stepwise intra-molecular transfer of three electrons from the nitrones to Au(III), and the release of the resulting Au(0). The phosphoryl group in the nitrones suppressed the first ligand-exchange interaction by its electronegativity, while the group promoted the electron transfer from the nitrones to Au(III) by its inductive effect.
Feruloyl sucrose derivatives from Bistorta manshuriensis
Authors: Kim Ki Hyun , Chang Sang Wook , Lee Kang Ro
Published: May 2010

Bistorta manshuriensis is a well-known Korean medicinal plant traditionally used to treat diarrhea. Phytochemical investigation of the aerial parts of B. manshuriensis led to the isolation of two new feruloyl sucrose derivatives, bistoroside A (1) and bistoroside B (2), together with three known compounds, helonioside A (3), helonioside B (4), and smilaside L (5). The structures of the new compounds were elucidated as (3,6-di-O-Z-feruloyl)-β-D-fructofuranosyl-(1→2)-α-D-glucopyranoside (1) and (3,6-di-O-Z-feruloyl)-β-D-fructofuranosyl-(1→2)-(6′-O-acetyl)-α-D-glucopyranoside (2) on the basis of extensive analysis of 1D and 2D NMR (HMQC and HMBC), HR-FAB-MS, and chemical evidence.
An efficient and selective method for the preparation of triphenylmethyl ethers of alcohols and nucleosides
Authors: Zekri Negar , Alamdari Reza Fareghi
Published: May 2010

A very simple and efficient method is described for the protection of alcohols and nucleosides with benzyl monomethoxytrityl and benzyl dimethoxytrityl ethers in the presence of diethylazodicarboxylate and a catalytic amount of ceric triflate. High selectivity was observed for the tritylation of 5′-OH function of nucleosides.
Redox reactions of reactive oxygen species in aqueous solutions as the probe for scanning electrochemical microscopy of single live T24 cells
Authors: Zhao Xiaocui , Zhang Mengni , Long Yitao , Ding Zhifeng
Published: May 2010

The redox reactions of two main components of reactive oxygen species (ROS), superoxide and hydrogen peroxide, along with oxygen in aqueous solutions were investigated using a conventional electrochemical technique, differential pulse voltammetry (DPV). Superoxide undergoes oxidation at a Pt working electrode biased at 0.055 V versus Ag/AgCl, while hydrogen peroxide can be oxidized and reduced at 0.817 and –0.745 V, respectively. Oxygen in the solutions is reduced at the electrode with an applied potential of –0.455 V. Based on these results, hydrogen peroxide and superoxide released from live cells can be successfully monitored, identified, and mapped using scanning electrochemical microscopy (SECM) at different potentials. Single human bladder (T24) cells were imaged using a 5 μm diameter SECM probe biased at –0.400, –0.600, and –0.800 V. Oxygen reduction that seems an interference can be discriminated from that of hydrogen peroxide by means of SECM.
THE PSEUDO-INDEX OF HOROSPHERICAL FANO VARIETIES
Authors: PASQUIER BORIS
Published: May 2010

We prove a conjecture of Bonavero et al. on the pseudo-index of smooth Fano varieties, in the special case of horospherical varieties.
UNITARIES IN A SIMPLE C*-ALGEBRA OF TRACIAL RANK ONE
Authors: LIN HUAXIN
Published: May 2010

Let A be a unital separable simple infinite dimensional C*-algebra with tracial rank not more than one and with the tracial state space T(A) and let U(A) be the unitary group of A. Suppose that u ∈ U0(A), the connected component of U(A) containing the identity. We show that, for any ϵ > 0, there exists a self-adjoint element h ∈ As.a such that [Formula: see text] We also study the problem when u can be approximated by unitaries in A with finite spectrum.

Denote by CU(A) the closure of the subgroup of unitary group of U(A) generated by its commutators. It is known that CU(A) ⊂ U0(A). Denote by [Formula: see text] the affine function on T(A) defined by [Formula: see text]. We show that u can be approximated by unitaries in A with finite spectrum if and only if u ∈ CU(A) and [Formula: see text] for all n ≥ 1. Examples are given for which there are unitaries in CU(A) which cannot be approximated by unitaries with finite spectrum. Significantly these results are obtained in the absence of amenability.
ON BOUNDED WEAK AND PSEUDO-SOLUTIONS OF NONLINEAR DIFFERENTIAL EQUATIONS HAVING TRICHOTOMY WITH AND WITHOUT DELAY IN BANACH SPACES
Authors: GOMAA ADEL MAHMOUD
Published: May 2010

In the present work we consider E is a Banach space, E* is its dual space and L(E) is the space of continuous linear operators from E to itself. A function x: ℝ → E is said to be a pseudo-solution of the equation [Formula: see text] where A:ℝ → L(E) is strongly measurable and Bochner integrable function on every finite subinterval of ℝ with f:ℝ × E → E is only assumed to be weakly weakly sequentially continuous or Pettis-integrable and the linear equation [Formula: see text] has a trichotomy with constants α ≥ 1 and σ > 0, if x is absolutely continuous function and for each x* ∈ E* there exists a negligible set ℵx* such that for each t ∉ ℵx*, then we have [Formula: see text] We give an existence theorem for bounded weak and pseudo-solutions of the nonlinear differential equations [Formula: see text] Let T, r, d > 0, Br = {x > E: ‖x‖ ≤ r} and CE([-d,0]) be the Banach space of continuous functions from [-d,0] into E. Finally we prove an existence result for the differential equation with delay [Formula: see text] where fd : [a,b] × CE([-d,0]) → E is weakly weakly sequentially continuous function, [Formula: see text] is strongly measurable and Bochner integrable operator on [a,b] and θtx(s) = x(t + s) for all s ∈ [-d,0].
INSTABILITY IN THE PRESENCE OF AN INDEFINITE CONSERVATION LAW
Authors: BIRTEA PETRE
Published: May 2010

Consider a C1 vector field X on a finite-dimensional manifold M and xe an equilibrium point for the dynamics [Formula: see text]. We will prove that if I is a C2 constant of motion for X such that xe is also a critical point of I, then [Formula: see text] is a constant of motion for the linearized system [Formula: see text]. As a consequence we will give an instability result under the condition that [Formula: see text] is an indefinite quadratic form. If xe is not a critical point of I, then we obtain [Formula: see text] as a constant of motion for the linearized system.
GEOMETRIC REALIZATIONS OF KAEHLER AND OF PARA-KAEHLER CURVATURE MODELS
Authors: BROZOS-VÁZQUEZ M. , GILKEY P. , MERINO E.
Published: May 2010

We show that every Kaehler algebraic curvature tensor is geometrically realizable by a Kaehler manifold of constant scalar curvature. We also show that every para-Kaehler algebraic curvature tensor is geometrically realizable by a para-Kaehler manifold of constant scalar curvature.
WAVE PACKETS ON SPHERICAL SURFACE VIEWED FROM EXPECTATION VALUES OF CARTESIAN VARIABLES
Authors: ZHU X. M. , XU M. , LIU Q. H.
Published: May 2010

It is demonstrated that the Cartesian momenta and positions offer a proper description for the motion of particles constrained on the surface of a sphere. In classical limit, their mean values on the classical wave packet go over to classical quantities.
A fast algorithm and datalog inexpressibility for temporal reasoning
Authors: Bodirsky Manuel , Kára Jan
Published: May 2010

We introduce a new tractable temporal constraint language, which strictly contains the Ord-Horn language of Bürkert and Nebel and the class of AND/OR precedence constraints. The algorithm we present for this language decides whether a given set of constraints is consistent in time that is quadratic in the input size. We also prove that (unlike Ord-Horn) the constraint satisfaction problem of this language cannot be solved by Datalog or by establishing local consistency.
Deciding strategy properties of contract-signing protocols
Authors: Kähler Detlef , Küsters Ralf , Wilke Thomas
Published: May 2010

Research on the automatic analysis of cryptographic protocols has so far concentrated on reachability properties, such as secrecy and authentication. In this article, we prove that certain game-theoretic security properties, including balance for contract-signing protocols, can be decided in a Dolev-Yao style model with a bounded number of sessions. The decision algorithm that we develop is based on standard constraint-solving procedures, which, in the past, have successfully been employed in tools for reachability properties. Our result thus paves the way for extending these tools to deal with game-theoretic security properties.
Complexity of propositional proofs under a promise
Authors: Dershowitz Nachum , Tzameret Iddo
Published: May 2010

We study—within the framework of propositional proof complexity—the problem of certifying unsatisfiability of CNF formulas under the promise that any satisfiable formula has many satisfying assignments, where
many
stands for an explicitly specified function Λ in the number of variables
n
. To this end, we develop propositional proof systems under different measures of promises (i.e., different Λ) as extensions of resolution. This is done by augmenting resolution with axioms that, roughly, can eliminate sets of truth assignments defined by Boolean circuits. We then investigate the complexity of such systems, obtaining an exponential separation in the average case between resolution under different size promises:

(1) Resolution has polynomial-size refutations for all unsatisfiable 3CNF formulas when the promise is ϵ…2

n

, for any constant 0<ϵ<1.

(2) There are no subexponential size resolution refutations for random 3CNF formulas, when the promise is 2

Δ
n

, for any constant 0<δ<1 (and the number of clauses is
O
(
n
3/2-ϵ
), for 0<ϵ<1/2).

“
Goods Satisfactory or Money Refunded
”

—The Eaton Promise
Lower bounds for bounded depth Frege proofs via Pudlák-Buss games
Authors: Ben-Sasson Eli , Harsha Prahladh
Published: May 2010

We present a simple proof of the bounded-depth Frege proof lower bounds of Pitassi et al. [1993] and Krajíček et al. [1995] for the pigeonhole principle. Our method uses the interpretation of proofs as two player games given by Pudlák and Buss. Our lower bound is conceptually simpler than previous ones, and relies on tools and intuition that are well known in the context of computational complexity. This makes the lower bound of Pitassi et al. [1993] and Krajíček et al. [1995] accessible to the general computational complexity audience. We hope this new view will open new directions for research in proof complexity.